BACKGROUND OF THE INVENTION
[0001] This invention relates in a first aspect to an electric rotary power tool apparatus
holdable by hand during operation; in a second aspect to a kit comprising the novel
apparatus, and in a third aspect to novel switch means therefor.
[0002] The power tool apparatus according to the first invention aspect consists essentially
of
[0003] (A) a first building block comprising
(1) an apparatus casing consisting essentially of an elongated assembly having
a longitudinal axis and comprising
(1.1) an enveloping shell extending generally in the direction of the said longitudinal
axis, and having an open front end and an open rear end; and being of one piece;
(1.2) a first transverse wall extending across the interior of the shell in a
region thereof intermediate the said front end and the said rear end axially spaced
from both these ends so as to divide the shell interior into a forward chamber and
a rearward chamber; the first transverse wall has a throughhole therein and is integral
with the said shell;
(1.3) a second transverse wall across the open rear end of the shell and being
detachably mounted therein; the second transverse wall has an opening therein; and
(1.4) a speed-reducing unit which is mounted on the second transverse wall on
the side thereof facing toward the first transverse wall, and comprises a driven power-transmitting
shaft having a driven shaft front end adapted for fitting into the said throughhole
and protruding therefrom into the forward chamber of the shell;
[0004] (B) a second, rearward building block comprising
(2) a motor comprising, in turn,
(2.1) a motor housing having a central longitudinal axis substantially parallel
with the elongated assembly axis, and comprising a surrounding hull, a forward hull
end, a rearward hull end wall, and being adapted for having the front end thereof
rigidly connected with the second transverse wall on the outside of the latter;
(2.2) driving motor shaft means extending through the interior of the motor housing
and being rotatably supported in the opening of the second transverse wall; the driving
rotor shaft means have a forward shaft end extend into the rearward shell chamber
and are adapted for drivingly engaging the said speed-reducing unit therein; and
(3) insertable bearing-wall means adapted for being mounted transversely in rigid,
detachable connection, in the said open front end of the enveloping shell, and having
a central axial throughhole; these insertable bearing-wall means comprise
(3.1) shaft-bearing means in the axial throughhole in which a driven power-transmitting
shaft of the power tool apparatus can be supported.
[0005] An apparatus of the type described hereinbefore has been disclosed by V. Raso and
A. C. Eisenhart in their patent 3,434,366 granted March 25, 1969.
[0006] However, this known apparatus is not intended to be held by hand, especially during
operation, but is to be mounted stationary on a solid base 5 on supporting feet 156
(Fig. 1 of Patent 3,434,366).
[0007] If it were adapted to be used by hand it could be used for short tools such as sockets
for tightening and loosening nuts or for screwdrivers. However, no heavy duty work
could be done with such a power tool, when of reduced size to render it holdable by
hand,as the apparatus lacks power-enhancing means such as an impact clutch or the
like and could not support the same inside the forward housing of the frame or enveloping
sleeve which is only intended to house a gear reduction unit distributed over both
the forward and the rearward chamber which are formed in the frame of the Raso et
al reduction unit.
[0008] A known electrical switch adapted to be mounted on the end part of an electric motor
next adjacent the commutator thereof has been described in Patent 3,681,550 issued
on August 1st, 1972 to Perry and Brockelsby. In this known electrical switch, contactor
pins 66 extend from a rearward outer plate 62 corresponding to a cap member end wall,
infra, in a switch structure through an intermediary cap member 54 into a pivotable
brush mounting plate 40 in which there are housed four brushes 47 which are urged
with their contactable forward end faces against an insulating wafer 26 having four
openings 32 to 35 therein. As the brushes come to register with these openings owing
to rotation of the brush mounting plate relative to the wafer, the brushes will penetrate
through the openings and come into contact with a conically-shaped surface composed
of commutator segments. Flexible wire connections are provided within the brush mounting
plate and connect the brushes with the ends of the connector pins lodged in the brush
mounting plate.
[0009] This known switch is thus of rather complicated structure and suffers from a considerable
number of points where the various elements are subject to relatively rapid wear.
[0010] In the prior power-tool apparatus known to me, an exchange of impact means or the
like present in a forward chamber of the apparatus casing is only provided for by
making the forward part of the apparatus casing detachable from the rearward part
thereof housing the speed-reducing unit. After the forward apparatus part has been
detached, the impact clutch or the like power-transmitting means housed therein can
be withdrawn from the forward chamber only by way of the rearward end of the forward
part, or, depending on the structure of each casing, part or all of the speed-reducing
unit must be removed, before another type of power-transmitting unit can be inserted
in that forward chamber.
[0011] This is the case in the power tool apparatus described in my United States patent
4,505,170 dated March 19, 1985; in U.S. patent 4,368,784 to Wünsch et al, granted
on January 18, 1983; in German Offenlegungsschrift DE 30 07 630, applied for by Rodac
Pneumatic Tools, Carson, California, and publlished on March 12, 1981 (U.S. application
70149 filed on August 27, 1979); in German Offenlegungsschrift DE 30 15 423, applied
for by Robert Bosch GmbH, Stuttgart, Germany, and published on October 29, 1981; and
in Swiss patent 553,625 granted to Atlas Copco Aktiebolaget, Nacka, Sweden and published
on September 13, 1974.
OBJECTS AND SUMMARY OF THE INVENTION
[0012] It is a first object of this invention to provide a novel electric rotary power tool
apparatus which is holdable by hand, powerful enough for heavy duty work, and of
a configuration well balanced in hand, also when a heavy duty tool is attached via
suitable, known transmission means, to the driven shaft of the speed reducing unit.
[0013] It is another object of the invention to provide an electric rotary power tool apparatus
holdable by hand during operation, which permits the operator to rapidly exchange
tools while working with the apparatus.
[0014] It is a further object of the invention to provide a power tool apparatus holdable
by hand during operation and having a forward housing part integral with the remaining
housing thereof, into which power-transmitting means of different types, among them
also impact clutches and the like, can be inserted without separation of the forward
housing part, thereby facilitating rapid exchange of different types of insets, in
particular during heavy duty work being carried out with the apparatus.
[0015] It is yet another object of the invention to provide a kit comprising the novel electric
rotary power tool apparatus as well as a set of a great variety of light and heavy
duty tools which can be exchanged easily by the operator even when at such working
sites as scaffoldings of a high building.
[0016] It is still another object of the invention to provide a novel type of electric switch
particularly for switching direct electrical current, with a minimum of power loss
also when switching strong electrical currents having a potential of preferably from
8 to about 40 volts and an amperage sufficient for affording a power input into the
electric motor of at least about 180 watt, when idling, and at least 620 watt when
under load.
[0017] It is furthermore an object to provide an electrical switch adapted to be mounted
at the rear end of an electric motor next adjacent a commutator mounted on the rotor
shaft of the motor, which switch is distinguished by a reduced number of elements
of greatly simplified structure in which the number of points at which wear of parts
may occur as well as the rate of wear of such parts have been reduced considerably.
[0018] These objects are attained, as described hereinafter, in an apparatus of the initially
described kind, in which the rearward chamber of the enveloping shell is destined
to receive therein the entire speed-reducing unit which is adapted to fit in that
chamber; as well as by novel switch means described further below.
[0019] The transverse wall in the central region of the enveloping shell, which wall is
an integral part of the shell body, is destined to receive in its opening the driven
output shaft of the speed-reducing unit which latter is confined to the rearward
chamber of the enveloping shell. The forward chamber in this shell is destined to
receive therein
[0020] (C) a third, inset building block adapted for being practically completely inserted
therein by way of the open front end of the said forward shell chamber, and comprising,
besides the initially described shaft-bearing means,
(3.2) intermediary power-transmitting insert means comprising
(3.2.a) insert shaft means having a forward and a rearward shaft end, of which
the rearward shaft end is adapted for driving engagement with the driven shaft front
end protruding into the forward shell chamber; the insert shaft means are supported
for rotation in the shaft-bearing means in a region of the insert shaft means near
the forward shaft end thereof; and
(3.2.b) a connecting piece on the forward shaft end and forward of the shaft bearing
means;
(3.3) centering socket means adapted for protruding forward out of the enveloping
shell and being located spaced outwardly from said throughhole; and
(3.4) tool fastener-engaging means adapted to be located outside the shell and
spaced outwardly of the axial throughhole. These may, for instance, be boltholes.
[0021] As further important features of the invention,
(i) the length of the enveloping shell forward chamber from the integral first
transverse wall to the open shell front end must be sufficient for receiving in its
interior all parts of the third building block that are located rearward of the central
axial throughhole in the insertable bearing-wall means; and
(ii) the wall thickness and strength of the enveloping shell must be sufficient
for supporting, when held freely by hand during operation, in combination with the
first building block, the entire second, rearward building block comprising the
motor mounted on the second transverse wall, as well as the entire third, inset building
block even when comprising heavy duty impact clutch means or the like, as part of
the said intermediary power-transmitting insert means.
[0022] Of course, the open front end of the enveloping shell must be wide enough to permit
easy insertion of such power-transmitting units as impact clutches, fan means and
the like.
[0023] Preferably, the aforesaid speed-reducing unit comprises a gear train consisting essentially
of a plurality of gears and a number of transmission shafts each bearing at least
one gear, one of which gears is a pinion adapted for being mounted on the forward
shaft end of the driving rotor shaft means, and one of the transmission shafts is
comprised by the said driven power-transmitting shaft means; the transmission shafts
are supported in the first and second transverse walls, respectively. Optimal power
output is obtained when the ratio of the speed of the driving rotor shaft means to
the driven power-transmitting shaft means is from about 7:1 to about 12:1.
[0024] I have found the above-mentioned transmission ratio of from about 7:1 to 12:1 to
be critical, because below and above that ration, even though the resulting speed
of the driven shaft is about 1200 to 4000 r.p.m., the apparatus will fail to loosen
severely jammed or seized bolts or nuts of automobile wheels in an increasing number
of cases, the greater the difference from the above-stated range of ratioes. The choice
of the transmission ratio is dependent on the idling speed of the driven shaft of
the motor; thus, when that idling speed is 30 000 r.p.m., a transmission ratio of
12:1 is preferred. If a ratio of 7:1 were used, a flywheel effect might be produced
by the impact mass and an impact-generating unit would be no more effective and might
even be damaged.
[0025] The motor comprised by the rearward building block is preferably an electric motor
comprising
(2.3) a rotor mounted inside the motor housing on the driving rotor shaft means
for rotating the latter;
(2.4) stator means adapted for generating an electric field for cooperation with
said rotor; and
(2.5) commutator means comprising
(2.5.a) a commutator consisting essentially of collector segments and being mounted
on the driving rotor shaft means between the rotor and the said rearward motor housing
end wall;
(2.5.b.) first and second brush means mounted in the motor housing and biassed
toward the collector segments for electrically conductive contact therewith to deliver,
preferably direct, electric current to the rotor;
(2.5.c.) first and second fixed contactor means being electrically conductively
connected with the first and second brush means, respectively, and being mounted
stationary in the rearward building block and having terminal portions located outside
the rearward motor housing end wall; the fixed contactor terminal portions bearing
contactable surface regions located generally in a substantially planar contact zone;
and
(2.5.d.) electrically conductive lead means adapted for connecting the first and
second brush means, respectively with the first and second fixed contactor means,
sub stantially free from electrical power losses. This last-mentioned advantageous
feature is achieved by providing lead means of a sufficiently large cross sectional
area, and by avoiding at the junctions between the lead means and other conductive
elements all soldered joints, using instead clamping-in connections ensuring metal-on-metal
pressure contact.
[0026] In a preferred embodiment of the electric motor, the stator means comprise
a stator mounted in the interior of the motor housing and being a permanent magnet
of magnetic iron material, the permanent magnet comprising a north pole shoe and a
south pole shoe of substantially semicylindrical configuration and having each a thickness
of from about 5 to 6 mm, the pole shoes of the permanent magnet being concentrical
with the longitudinal rotor axis; and opposite longitudinal gaps having each a circumferential
width, in a radial plane, of about 33 mm and separating said two pole shoes from one
another; the length of the permanent magnet being from about 30 to 65 mm; and the
radial diameter of the assembled rotor and two pole shoes taken together being from
about 42 to 45 mm;
and the rotor consists essentially of
(i) a generally drum-shaped armature on the rotor shaft and having a substantially
cylindrical surface section coaxial with the longitudinal rotor axis and with an external
diameter of about 32 mm and a length of from about 26 to 55 mm, the armature having
12 axially extending cutout channels parallel with the longitudinal rotor axis and
opening out of the external surface section of the armature; the internal diameter
of said armature between the deepest ends of every two diametrically opposite cut-out
channels being from about 16 to 17 mm,
(ii) a wiring of electrically conductive wire having a diameter of each individual
wire cross section of from about 0.56 to 0.72 mm and comprising a plurality of wire
portions, each of the channels containing about 30 to 37 of the wire portions, and
(iii) the commutator comprises 12 collector segments and is mounted on the rotor
shaft; and the total length of wire amounts to from about 12 to about 24 meters.
[0027] All measures are taken to ensure a minimum of resistance losses in the paths of direct
electric current between the current source and the collector segments of the motor
armature. Thus, the cables used to connect the +pole and the -pole of the battery
with the corresponding connecting contactor elements of the switch preferably comprise
a parcel of fifty wires each being 0.25 mm thick, the parcel having a diameter of
2.5 mm, when a normal car battery is being used, while, in the case of a truck (lorry)
battery the parcel has a diameter of about 3 mm and consists of fifty wires each having
a thickness of 0.38 mm.
[0028] The electric motor is preferably devised to be fed an electric direct current from
an automobile battery having a nominal voltage of 12 volts and an operational voltage
of at least 10 volts, a power output of at least 250 watt;and the idling speed of
the motor at that voltage ranges from about 10 000 to 25 000 r.p.m., the transmission
ratio is 7:1 to 12:1 and the driven shaft has correspondingly an idling speed of above
1200 and up to 4000 r.p.m., and preferably a speed from about 1200 to 2200 r.p.m.
[0029] Most preferred is an idling speed of the motor of from 13 000 to 15 000 r.p.m.
[0030] It would have been expected that such high speed which means less strength of the
motor, would be too weak and therefore fail to loosen severely jammed or seized bolts
or nuts when a speed of 7000 r.p.m. would fail if the motor receives its direct current
from a 12 volt-automobile battery.
[0031] When the energy is supplied to the power tool apparatus according to this first invention
aspect from a 12 volt-automobile battery, then the speed of the driving motor shaft,
at the nominal voltage of 12 volts, should at least be 4000 r.p.m. under full load.
[0032] The amperage of the power source (preferably a car battery of 12 or 24 volts) delivered
to the tool apparatus ac cording to the invention under load should be at least 20
and preferably 125 up to 150 amperes, and from 180 amperes up to 300 to 400 amperes
for heavy duty work.
[0033] The rearward building block further preferably comprises
(4) an electrical switch means being adapted for switching a direct electrical
current having an electric potential of from 8 to about 40 volts and an amperage sufficient
for affording a power input of the electric motor of 180 watt, when idling, and, under
load, of 620 watt. These electrical switch means according to the invention comprise
(4.1) a supporting member having at least one electrically insulating face located
spaced from, and substantially parallel with, the above-mentioned substantially planar
contact zone, in which the contactable surface regions of the fixed contactors are
located; this insulating face is also located remote from the rearward motor housing
wall and the said planar contact zone. The contactable surface regions of the terminal
fixed contactor portions are preferably arranged about a common central switch axis
extending normal with regard to the contact zone; and
the supporting member is mounted in the rearward building block to be adapted
for pivoting displacement about the said central switch axis, between a neutral position
and at least one activating position.
[0034] The novel switch means further comprise
(4.2) socket throughholes extending through the supporting member and opening
out of the electrically insulating face thereof; they are preferably adapted for
receiving therein each a prong of an electrical plug having at least two prongs and
being electrically connectable to a source of electric current. The switch means further
comprise:
(4.3) at least two shiftable contactor elements being mounted on the electrically
insulating face of the supporting member so as to be electrically insulated from
each other, and each of the contactor elements is located so close to a different
one of the throughholes in the supporting member face as to make substantially loss-free
contact with a prong of a plug inserted in the respective throughhole; and wherein
each of said shiftable contact members has a shiftable contact face extending
in an arc about and on opposite sides of said central switch axis; and
(4.4) biassing means mounted in the rearward building block and being adapted
for biassing the shiftable contactor elements toward the fixed contactor means and
thereby urging the contact faces of the shiftable contactor elements into the substantially
planar contact zone; the contact faces which extend in the said arcs are separated
by gaps between them exposing non-conductive areas which the said biassing means urge
against the contactable surface regions of the terminal fixed contactor portions when
the supporting member is in neutral position, thereby preventing electric current
flow from said shiftable contact faces into the said contactable surface regions.
However, these non-conductive area gaps are sufficiently small for permitting current
flow, - when the supporting member is pivoted by a small angle about the central
switch axis and away from its neutral position,- from a source of electric energy
via the plug prongs and the shiftable contact faces into the contactable surface regions,
thereby energizing the electric motor.
[0035] In preferred embodiments of the apparatus, the rearward building block further comprises
(5) a cap member adapted for covering the rearward motor housing end wall as well
as a substantial portion of the surrounding hull of the motor housing on the outside,
and having a cap end wall extending substantially parallel with the rearward motor
housing end wall and having an inner wall surface, whereby an internal chamber is
left free between the inner cap wall surface and the rearward motor housing end
wall;
the supporting member of the electrical switch means is located in this embodiment
vis-á-vis the said inner face of the cap end wall, and cap throughholes are provided
which extend from outside the cap end wall to the inner face thereof facing the supporting
member.
[0036] Moreover, in this embodiment, the biassing means comprise first and second engagement
means, mounted on the out side of the rearward motor housing end wall and on the
insulating supporting member face, respectively; they cooperate with each other in
biassing the supporting member toward the rearward motor housing end wall and, when
said supporting member is in neutral position, they urge the non-conductive gap areas
against the contactable terminal portion surface regions, and, when the supporting
member is in an activating position, they urge the contact faces of the shiftable
contactor elements against the contactable surface regions in the substantially planar
contact zone.
[0037] The shiftable contactor elements when being arc-shaped preferably extend each over
an arc constituting a major portion of a half circle about the central switch axis,
and the arc-shaped contactor elements can have at least one end thereof beveled to
form a ramp facilitating sliding of the contact face thereon on to the respective
contactable surface region of the nearest fixed contactor terminal portion, when the
supporting member is pivoted through a small angle from the neutral to an activating
position.
[0038] Another advantageous embodiment of an electric switch according to the invention
is constituted by an on-off reversing switch comprising supporting means, spaced
from and pivotally mounted on an external face of the rear end wall of the motor housing
and having an inner and an outer face both extending substantially transversely to
the longitudinal rotor axis;
a pair of shiftable contactor means mounted in the supporting means and extending
from outside the outer face thereof through the cap member and protruding from the
inner face thereof toward the rear end wall of the motor housing, the supporting means
having passage means for the introduction of a pair of lead means from a plus pole
and a minus pole, respectively of an automobile battery or the like into the interspace
between the rear end wall and the inner face of the cap member, and into electrically
conductive engagement with a first and a second one, respectively, of the pair of
shiftable contactor means, the shiftable contactor means being so disposed in the
cap member as to be switched by corresponding turning of the cap member to adopt three
different positions, in a first "off" one of which, parts of the shiftable contactor
means at the inner face of the cover means are out of contact with both the first
and second stationary contactor means, while in a second position, a first one of
the shiftable contactor means makes contact with the first stationary contactor means
lodged in the rear motor housing end wall on the outside thereof, and the second
shiftable contactor means makes contact with the second stationary contactor means
also on the outside of the rear end wall, thereby activating the motor for rotating
the driving shaft in a given direction of rotation, and, in a third position, the
second one of the shiftable contactor means makes contact with the first sta tionary
contactor means, and the first shiftable contactor means makes contact with the second
stationary contactor means, thereby reversing the direction of rotation of the motor
and the driving shaft
[0039] It is furthermore preferred that the electrical switch means comprise restoring means
for returning the supporting member automatically from an activating position to its
neutral position; these restoring means comprise a shaft member whose cross sectional
area is of elongated configuration and has a larger diameter in a first direction
and a smaller diameter in a second direction at right angle to the said first direction,
and two elastically flexible blade members lie firmly and straight against opposite
flanks of the shaft member spaced from each other by the said smaller diameter when
the supporting member is in neutral position, and lying with biassing torque against
two other opposite flanks of the shaft member, spaced by the said larger diameter
from each other,when the supporting member is in an activating position: the resulting
torque biasses the shaft member toward return to its neutral position, one of the
two parts being constituted by the supporting member insulating face and the rearward
motor housing end wall bearing the shaft member, and the other part being constituted
by the two blade members.
[0040] In another embodiment of the switch according to the invention, the supporting member
can have a circumferential rim and can be mounted in the cap member pivotably about
the central switch axis; while the cap member is connected rigidly with the rearward
motor housing wall; and the supporting member can then comprise
(4.1.a) a switch-shifting member protruding tangentially from said supporting
member rim; and
the cap member can then be provided with a window registering with the switch-shifting
member through which window the switch-shifting member protrudes when the supporting
member is in neutral position; depression of the protruding end of the switch-shifting
member causing the supporting member to turn about the central switch axis and shift
from its neutral to an activating position.
[0041] In a kit containing the above-described novel power tool apparatus being holdable
by hand during operation, there can be provided, as a supplementary part of the rearward
building block
(6) a handle part having at least two opposite handle sidewalls and being firmly
connectable with the first building block, the handle part having a central longitudinal
axis extending transverse relative to the longitudinal building block assembly axis;
while the electrical switch means further comprise
(4.5) auxiliary stationary mounting means adapted for holding a third and fourth
fixed contactor means firmly in position therein relative to a central switch axis
extending normal to the mounting means; these auxiliary mounting means are mounted
in the said handle part on an inside face of one of the opposite handle sidewalls;
while a special supporting member is mounted, pivotably relative to the last-mentioned
central switch axis, on an inside face of the other handle sidewall, in cooperative
juxtaposition to the fixed contactor means on the stationary mounting means.
[0042] In yet another embodiment of the electrical switch according to the invention, the
special supporting member has a circumferential rim and comprises
(4.1.a) at least one switch-shifting member protruding tangentially from the supporting
member rim,
while the handle part has window means through which the switch-shifting member
is adapted to protrude at least when the supporting member is in neutral position;
depression of the protruding end of the switch-shifting member will cause the supporting
member to turn by a small angle about the last-mentioned central switch axis and will
thus be shifted from its neutral to an activating position.
[0043] A similar embodiment of the apparatus according to the invention can be built up
from a rearward building block which comprises, as part of the electrical switch means,
(4.6) stationary mounting means adapted for holding the first and second fixed
contactor means firmly in position therein relative to the first-mentioned central
switch axis, and being mounted firmly on the outside of the rearward motor housing
end wall;
while the first and second engagement means of the biassing means are aligned
with each other along the said central switch axis and are pivotably connected with
the cap member and the supporting member therein, and with the said stationary mounting
means, respectively;
and the said switch means comprise further
(4.7) restoring means being in engagement with the supporting member and comprising
arresting means adapted for being held in the stationary mounting means so as to cause
restoring bias applied to the supporting member when the latter is pivoted from neutral
position to an activating position;
and the said rearward building block further comprises, as part of the kit, separately,
(6) a handle unit having at least two opposite handle sidewalls and being firmly
connectable with the first building block, the handle part having a central longitudinal
axis between the handle sidewalls and extending transversely to the central longitudinal
motor housing axis; and
the opposite handle sidewalls have upper end portions adapted for freely supporting
the cap member in a manner such that the said cap member and the said supporting member
therein can be pivoted between neutral position and an activating position of the
supporting member;
and the handle unit contains further
(7) a second electrical switch having a second central switch axis and comprising
(7.1) a pair of third and fourth fixed contactor means,
(7.2) second stationary mounting means adapted for holding the third and fourth
fixed contactor means firmly in position therein relative to the second switch axis,
and being mounted in the handle part on an inside face of one of the said opposite
handle sidewalls; and
the third and fourth fixed contactor means have terminal portions protruding,
into an interspace between the opposite handle sidewalls from the second mounting
means, and bear fixed contactable third and fourth surface regions, respectively,
located generally in a second planar contact zone;
(7.3) electrically conductive cord means extending through the handle unit, having
two ends, one end of which cord means is connected to the third and fourth contactor
means; while, at the other end thereof, the cord means comprise plug means adapted
for being inserted through the cap member into contact with the contactable regions
of the first and second contactor means;
(7.4) secondary throughholes in the cap member for rendering the contactable regions
of the first and second contactor means accessible to contact by plug means inserted
in these secondary throughholes;
(7.5) a second supporting member having at least one electrically insulating face
located spaced from, and substantially parallel with the said second planar contact
zone;
(7.6) handle socket throughholes opening out of the handle unit and being adapted
for receiving in each throughhole plug-connecting means associated with an electrical
plug being connectable to a source of electric direct current;
(7.7) at least two shiftable handle contactor elements being mounted on the said
insulating face of the second supporting member so as to be electrically insulated
from each other, and close to the said handle socket throughholes so as to make substantially
loss-free contact with the plug-connecting means when the electrical plug mentioned
under (7.6), supra, is connected to the handle socket throughholes;
(7.8) second biassing means mounted in the handle unit and comprising first and
second engagement means mutually pivotably engaged and cooperating with each other
in biassing the second supporting member toward the second stationary mounting means,
while being pivotable relative to each other, together with the second supporting
member and the second stationary mounting means;
and the second supporting member have a peripheral rim and comprise
(7.5.a) at least one switch-shifting member tangentially protruding from the
rim of the second supporting member, while the handle unit has window means through
which the switch-shifting member is adapted to protrude when the second supporting
member is in neutral position; whereas depression of the protruding end of the switch-shifting
member will cause the supporting member to turn through a small angle about the second
central switch axis and will thereby shift from its neutral to an activating position;
and, lastly, the second switch comprises
(7.9) second restoring means being in engagement with the second supporting member
and comprising second arresting means being held in the second stationary mounting
means so as to cause restoring bias to be applied to the second supporting member
when the same is pivoted from its neutral position to an activated position.
[0044] In yet a different combination of the basic apparatus according to the invention
and a handle part,
the first and second engagement means of the biassing means are aligned with each
other along their common central switch axis and are pivotally connected with the
supporting member inside the cap member and with the rearward motor housing end wall,
respectively; and
the rearward building block comprises further
the handle part described hereinbefore under (6),
the opposite handle sidewalls having upper end portions adapted for freely supporting
the cap member for rotating motion of the latter relative to the sidewalls between
the rest position and an activating position of the supporting member; and the handle
part comprises
(6.1) pivoting means for causing a pivoting motion of the cap member from the
said rest position to an activating position of the supporting member therein,
which pivoting means are located in the handle part and extend into engagement
with the cap member in an underside region of the latter intermediate the handle sidewalls;
and
(6.2) pivot-actuating means lodged in the handle part and adapted for being depressed
from outside the handle part, thereby causing the cap member to pivot from the rest
position to an activated position of the supporting member;
and the electrical switch means further comprise
(4.7) restoring means for restoring the supporting member, and the cap member
together therewith, automatically from an activating position to the said neutral
position. The restoring means can be mounted in the handle part and can be in restoring
engagement with the pivoting means therein.
[0045] On the other hand, the restoring means can be in restoring engagement with the supporting
member and can comprise arresting means;
and the electrical switch means can further comprise
(4.6) stationary mounting means adapted for holding the first and second fixed
contactor means firmly in position therein relative to the central switch axis, and
being mounted on the outside of the rearward motor housing end wall; while
the arresting means are held in the stationary mounting means so as to cause
restoring bias of the restoring means exerted on the supporting member when the latter
is pivoted from its neutral position to an activating position.
[0046] In yet another embodiment of the apparatus according to the invention, the rearward
building block can further comprise
(5) a cap member as described hereinbefore under (5),
and the first and second fixed contactor means extending to the cap end wall,
(4.2) the socket throughholes extend through the cap end wall to the outside thereof
and register with the con tactable surface regions of the fixed contactor terminal
portions and are adapted for receiving prongs of an electrical plug having at least
two such prongs and being connectable to a source of electric current; whereby prongs
inserted into the socket throughholes can be connected conductively with the contactable
surface regions;
one of the first and second fixed contactor means has a circuit-breaking gap therein;
and
this embodiment of an electrical switch comprises a circuit making element mounted
in the cap member and being adapted for radial inward displacement by outside pressure
being applied thereto, so as to bridge the gap in the one fixed contactor means and
thereby to make circuit; the circuit-breaking element is biassed into undepressed,
circuit-breaking position.
[0047] Acording to the second aspect of the invention, a working kit suitable for hobby
work as well as constructional and the like heavy duty work, comprises
(I) an electric rotary power tool apparatus holdable by hand during operation
and consisting essentially of
(A) a first building block comprising
(1) an apparatus casing consisting essentially of an elongated assembly having
a longitudinal axis and comprising the parts defined under (1.1) through (1.4), supra,
the speed-reducing unit comprising the gear train as defined supra, which reduces
the speed of the pinion to that of the driven shaft in a ratio of from about 7:1 to
about 12:1; and
(B) a second, rearward building block comprising
(2) a direct current electric motor comprising the parts defined, supra, under
(2.1) through (2.5.c) as well as
(2.5.d) electrically conductive lead means adapted for connecting the first brush
means with the first fixed contactor, and the second brush means with the second
fixed contactor, and being adapted for carrying direct electrical current of the voltage
and amperage defined, supra, substantially free from electrical power losses;
(4) first electrical switch means being adapted for switching a direct electrical
current having the voltage and amperage defined, supra, and comprising the parts (4.1)
through (4.7) as defined, supra;
(5) a cap member adapted for covering at least a substantial portion of the surrounding
hull of the motor housing and having a cap end wall extending substantially parallel
with and spaced from the outside of the rearward housing end wall, an internal chamber
being left free between the rearward hull end wall and the inner face of the cap
end wall, through which internal chamber the first planar contact plane extends; and
the first supporting means being located inside the cap member vis-á-vis the cap end
wall;
those socket throughholes being associated with the two shiftable contactor elements
of this first switch means extending from outside the cap member and through the latter
and also through the first supporting member, and two other, additional throughholes
extending from outside the cap end wall and through the first supporting member thereon,
and opening out of the electrically insulating face thereof to register with the contactable
terminal regions of the first and second fixed contactors, respectively, when the
supporting member is in neutral position;
while the first and second engagement means of the first biassing means are pivotably
engaged with each other, whereby the first supporting member in the cap member can
be pivoted about the first central switch axis relative to the first mounting means
by at least a small angle; and, when the first supporting member is in activated position,
the biassing means urge the shiftable contactor elements against the con tactable
terminal regions of the first and second fixed contactors.
[0048] This kit according to the invention further comprises
(II) at least one of the following kit items:
(a) an electrical cable having two ends and comprising at one end thereof connecting
means for attachment to a source of direct electrical current, and at the other end
an electrical plug comprising prong-receiving holes therein being electrically conductively
connected, through the cable, with the connecting means, and prongs adapted for being
mounted fixedly in at least one of (i) the socket throughholes of the first supporting
member, and (ii) the prong-receiving holes of the plug;
(b) a handle part having at least two opposite handle sidewalls and being firmly
and detachably connectable with the first building block, which handle part has a
central longitudinal axis extending between the handle sidewalls and transversely
to the central longitudinal motor housing axis, when the handle part is attached to
the first building block;
and the opposite handle sidewalls are adapted for freely supporting the cap member
and the first supporting member therein to be pivotable about the first central switch
axis between the said neutral position and an activating position.
[0049] This handle part comprises
(7) second electrical switch means adapted for switching a direct electrical
current having the voltage and amper age defined, supra, and comprising, about a
second central switch axis, the parts (7.1) through (7.9), described supra; and one
end of the cord means comprises
(6.1) a handle cord plug conductively connected with the other end of the cord
means, through the latter; and
(6.2) lead prongs on the cord plug adapted to be inserted, respectively, into
the additional socket throughholes in the cap end wall and to make contact, through
the first supporting member, with the contactable terminal regions of the first and
second fixed contactors, respectively, while arresting the first supporting member
in neutral position;
and the second supporting member comprises actuating means extending to the outside
and having a depressable portion protruding to outside the handle part at least when
the second supporting member is in neutral position; while depression of the depressable
portion of the actuating means causes the supporting member to pivot about the said
second central switch axis from its neutral position to an activating position;
(c) a portable battery adapted for being carried on an operator's person, in combination
with battery cable means adapted for being connected to the portable battery, on the
one hand, and being adapted to be connected, on the other hand, with one of
(iii) the said two shiftable contactor elements of the first supporting member;
or
(iv) the shiftable handle contactor elements of the second supporting member;
(III) at least one of the following insert units all of which have the following
features in common:
(3) insertable bearing-wall means adapted for being mounted transversely, detachably
and in firm position in the open front end of the enveloping shell of the first building
block, the insert bearing-wall means having a central axis throughhole and comprising
(3.1) shaft-bearing means in the axial throughhole;
(3.2) an insertable power-transmitting intermediary unit comprising
(3.2.a) insertable shaft means having a forward shaft end and a rearward insertable
shaft end, the insertable shaft means being supportable for rotation in the shaft-bearing
means engaging a region of the insertable shaft means near the forward shaft end,
the rearward shaft end of the insertable shaft means being adapted, upon insertion
into the forward chamber of the enveloping shell, for drivingly engaging the driven
shaft front end protruding from the first transverse wall into the forward shell chamber;
(3.2.b) a square-head type connecting piece on the forward end of the insertable
shaft means, and being located forward of the shaft-bearing means;
(3.3) centering socket means adapted for protruding forwardly out of the enveloping
shell and being located spaced outwardly from the throughhole; and
(3.4) tool-fastening means adapted for being located outside the enveloping shell
and being spaced outwardly from the axial throughhole;
and these insert units are constituted by:
(8A) an insert unit consisting of the parts defined under (3) through (3.4), supra,
per se;
(8B) an insert unit comprising, besides the parts defined under (3) through (3.4),
supra,
(8.1) fan means mounted on the insertable shaft means in a region thereof being
located in the interior of the forward chamber, upon insertion of the unit therein;
and
(8.2) vent means provided in the transverse walls of the forward and rearward
chambers of the enveloping shell, as well as in the insertable bearing-wall means;
(8C) an insert unit comprising, besides the parts defined under (3) through (3.4),
supra, an impact-generating unit mounted on the insertable bearing-wall means and
on the insertable shaft means;
(8D) an insert unit comprising, besides the parts defined under (3) through (3.4),
supra, a hammer drill mounted on the insertable shaft means.
[0050] All of these insert units must fit with their parts rearward of their bearing-wall
means, defined above, into the forward chamber of the enveloping shell;
and the working kit according to the invention further comprises:
(IV) at least one of the following tools each of which comprises
(9) coupling means adapted for firm, detachable and centered coupling of the respective
tool with the centering socket means; and
(10) tool operating shaft means comprising a coupling shaft end adapted for being
drivingly connected with the polygonal-type connecting piece at the forward end of
the insertable shaft means, preferably with a square head piece; and is constituted
by
(IV.1) nut-loosening and tightening socket means;
(IV.2) screw driver means;
(IV.3) a drilling tool;
(IV.4) a blade saw tool;
(IV.5) an angle tool comprising at least one of sander and cutter means:
[0051] In order to provide a successful power tool apparatus according to this second invention
aspect, the working kit preferably comprises an insert unit as defined under (8C)
or (8D), supra, whose impact-generating unit comprises an impact mass separate from
the motor and associated preferably with the tool socket means, mentioned under (IV.D),
supra, for imparting impacts to the latter means.
[0052] This impact generating unit comprises an impact mass and preferably imparts impacts
to the tool socket means at a frequency equal to the number of revolutions per minute
carried out by the driven shaft.
[0053] A preferred impact-generating unit comprises an anvil having at least two anvil abutments,
a hammer drum and at least two hammers thereon, the drum and hammers weighing together
about 350 to 550 grams and having a radial diameter of about 50 to 55 mm; a hammer
shaft connected with the driven shaft, the hammer drum being axially displaceable
along the hammer shaft; and a drum spring supported in the impacting unit to urge
the hammer drum and hammers into a position in which the hammers are enabled to impact
upon the anvil abutments when the hammer shaft is rotated; the hammer drum spring
having a length, measured along the rotor axis, of about 35 to 45 mm, and the compressibility
of the hammer drum being 10 mm under a load of about 18 to 22 kg.
[0054] In order to prevent generation of excessively high reaction forces (which would
exceed the strength of the operator holding the apparatus), the impact mass is urged
by means of a spring against slightly sloped contact faces of the driven tool socket.
The strength of the spring and the taper of the contact faces assures a continuous
tightening or loosening of bolts and the like elements up to the moment when the reaction
forces cause the impact mass to slip over a first sloped contact face and abut against
the next following sloped contact face. The impact action only starts when the reaction
forces surpass 50 Newtonmeters.
[0055] Another suitable impact-generating unit which can be equipped with the features defined
hereinbefore under (3.3) and (3.4) as described under (8C) and (8D), supra, is the
impact unit described by Georgy A. Antipov et al in Patent 4,191,264, patented on
March 4, 1980. The shank 8 described in this patent is suitable for use as the square-head
type connecting piece defined under (3.2.b), supra.
[0056] Automobile batteries have usually a nominal voltage of 12 volts, for passenger cars
and 24 volts for trucks, lorries, buses, agricultural combustion engines and the
like. The electric motor can therefore also be fed with D.C. from a 24-volt battery
(operational voltage at least 20 and up to 28 volts).
[0057] In a further aspect of the invention, the electric motor is preferably dimensioned
so as to be driven by an electric direct current having an operational voltage below
20 volts and, in particular, of about 9.5 to 14.5 volts; the speed of the said electric
motor, at a nominal voltage of 12 volts, should preferably not exceed 15 000 r.p.m.
when idling.
[0058] Such power tool apparatus having an electric motor of the last-mentioned characteristics
is useful in particular for hobby work such as drilling, honing, super-finishing,
fine-grinding, milling and the like operations which serve to change the shape of
an article of metal or synthetic resin material in some desired way.
[0059] The power tool apparatus according to this aspect of the invention can be obtained
by removing the impact-generating unit from the apparatus, thus leaving an apparatus
comprising only the motor and the speed-reducing unit adapted for transmitting torque
at a reduced speed to the tool socket means. However, it has been found that all of
this hobby work can be carried out equally well with the impact-generating unit in
place in the forward chamber of the enveloping shell.
[0060] When the impact-generating unit is removed from the forward sleeve chamber, it must,
of course, be replaced by, for instance, the insert shaft means of Insert unit 8A.
[0061] According to the third aspect of the invention there are provided electrical switch
means which comprise
(1) first and second fixed contactor means adapted for being,at one end thereof,
electrically conductively connected to electrical lead means constituting a first
part of a path of electric current flow, these first and second contactor means having,
at their other end, each a terminal portion bearing a contactable surface region;
(2) stationary mounting means adapted for holding the first and second fixed contactor
means firmly in position in a mounting face thereof relative to a central switch
axis normal to the said mounting face;
(3) a pivotable supporting member having at least one electrically insulating
face, each such insulating face being spaced from a different contactable surface
region of the first and second fixed contactor means;
(4) socket throughholes extending through the supporting member and opening out
of an electrically insulating face thereof, and being adapted for receiving each a
prong of an electric plug located in the said path of electric current flow;
(5) at least two shiftable contactor elements being mounted on the said electrically
insulating face of the supporting member so as to be insulatedly spaced from each
other and adapted for making contact with a prong of the said plug when the latter
has been inserted in a corresponding one of the said throughholes;
(6) biassing means comprising first and second engagement means; with the first
engagement means being mounted on the stationary mounting means, and the second engagement
means being mounted on the supporting member and being engaged with one another in
a manner such that the supporting member is pivotable through at least a small angle
relative to the stationary mounting means between a neutral and at least one circuit-making
position, and, when the supporting member is in an activated position, the biassing
means urge the shiftable contactor means against the contactable surface regions
of the fixed contactor terminal portions; and
(7) a cap member comprising a cap end wall and a hull part upstanding axially
therefrom about an inner face of the cap end wall; the inner face of the cap end wall
being turned toward a face of the pivotable supporting member facing away from the
electrically insulating face thereof.
[0062] In another embodiment of "on-off" and reversing electrical switch means according
to the invention, the contactable surface regions of the stationary contactor means
are located in the sidewalls of the terminal portions thereof, and the pair of shiftable
contactor means are pin-shaped, each have a contact region and are mounted in the
supporting member and extend substantially axially relative to the central switch
axis from outside the outer face of the supporting member through the cap member and
protrude from the inner face of the supporting member toward the stationary mounting
means and into a substantially planar contact zone by a distance such as the extend
parallel with the stationary contactor terminal portions by a sufficient length for
the lateral contact regions of the shiftable contactor means to make contact with
the contactable sidewall regions of the terminal portions in axially extending contact
zones thereof, when the supporting member is angularly pivoted into either one of
two limit positions relative to the stationary mounting means, while breaking contact
when in at least one intermediary position between the limit positions;
the cap members having passage means for the introduction of a pair of lead means
extending from a source of electric energy, into the interspace between the stationary
mounting means and the inner face of the cap member end wall and into electrically
conductive engagement with the pair of shiftable contactor means.
[0063] It is particularly important for a particularly superior functioning of the novel
switch that the first engagement means of the biassing means are mounted on a front
face of the stationary mounting means which front face is turned toward the supporting
member, and that the second engagement means are mounted on the same face of the supporting
member that bears the shiftable contactor elements, and that, while one of the said
first and second engagement means protrudes from the respective face bearing the same
into an interspace between the front face of the stationary mounting means and the
contactor elements-bearing face of the supporting member, the other engamenet means
protrude from the other face far enough into the said interspace to be engagement
with the first mentioned engagement means so that the supporting member is pivotable
relatively to the mounting means.
[0064] The substantially planar contact zone in which the fronward ends of the fixed contactor
means are located, extends through the above-mentioned interspace preferably substantially
parallel with the said front face of the stationary mounting means; and the contact-making
regions of the shiftable contactor elements on the supporting member must be movable
into the said planar contact zone; or viceversa, i.e., the substantially planar contact
zone extends substantially parallel with the contactors-bearing face of the supporting
member, then the contactable regions of the fixed contactor means must enbxtend into
that contact zone.
[0065] In the last described embodiment of the switch means according to the invention,
the shiftable contactors can be switched by a corresponding turn of the cap member
to adopt at least three different positions; in a first "off" position, parts of the
shiftable contactor means at the inner face of the cap member are out of contact with
both the first and the second stationary contactor means, while in a second posi
tion, a first one of the shiftable contactor means makes contact with the first stationary
contactor means lodged in the stationary mounting means, and the second shiftable
contactor means makes contact with the second stationary contactor means also projecting
from the stationary mounting means, thereby being capable of activating a motor for
rotating a driving shaft thereof in a given direction of rotation, and, in a third
position, the second one of the shiftable contactor means makes contact with the
first stationary contactor means, and the first shiftable contactor means makes contact
with the second stationary contactor means, thereby being capable of reversing the
direction of rotation of the said motor and the said driving shaft, or of a corresponding
machine.
[0066] Of two regions of the stationary and shiftable contactor means to be brought into
contact in order to make circuit, which regions consist of the aforesaid lateral contact
region and the contactable sidewall region, a first one preferably comprises inwardly
crimped contact spring parts, and the other region is pin-shaped so as to be clampingly
engagable by the first region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] Further objects and advantages of the invention will become apparent from the following
more detailed description thereof in connection with the accompanying drawings in
which
Fig. 1 is an axial sectional view of a schematical representation of a preferred
embodiment of the electric rotary power tool apparatus according to the invention
composed of three building blocks;
Fig. 2 is an axial sectional view of a similar embodiment, but with a different third
building block, comprising a first embodiment of an impact unit;
Fig. 2a is a detailed axial sectional view of the impact unit shown schematically
in Fig. 2;
Fig. 2b is a cross sectional view of the same impact unit taken in a plane indicated
by IIB - IIB in Fig. 2A;
Fig. 3 is an axial sectional view of an embodiment similar to that shown in Fig. 1,
but with a fan mounted on an insert shaft as part of the third building block;
Fig. 4 illustrates, more in detail, a first embodiment of the motor unit constituting
the second rearward building block, in a lateral view and partially in axial section;
Fig. 5 is a cross sectional view of the same embodiment of the motor unit taken in
a plane indicated by V - V in Fig. 4;
Fig. 6 is a partially cross sectional rear view of the rearward end of the motor unit
embodiment shown in Fig. 4, comprising a first embodiment of switch means;
Fig. 7 is a partially cut-open perspective view of the motor unit constituting the
second building block, with a second embodiment of novel switch means therein;
Fig. 8 is a partially axially sectional view of the rear portion of the embodiment
of the motor unit and switch means shown in Fig. 7;
Fig. 9 is an axially sectional view of a third embodiment of the switch means according
to the invention, taken in a plane indicated by IX - IX in Fig. 10, infra; with the
parts in neutral circuit-breaking position;
Fig. 10 is a rearward end view, partially cut open, of the embodiment of the novel
switch means shown in Fig. 1;
Fig. 11 is a view similar to that of Fig. 9, but with the parts in an activating position;
Fig. 12 is a view similar to Fig. 10, but with the parts in an activating position;
Fig. 13 is a view similar to that of Fig. 11, showing, in axial section, a first embodiment
of biassing means in the same embodiment of the switch means as shown in Figures 9
to 11.
Fig. 14 is an axial-sectional view of a second embodiment of the biassing means in
the switch means according to the invention;
Fig. 15 is a cross-sectional view of the embodiment of switch means and biassing means
taken in a plane indicated by XV - XV in Fig. 14, with the parts in neutral position;
Fig. 16 is a view similar to that of Fig. 15, with the parts in an activating position;
Fig. 17 is an exploded view of the parts constituting a third embodiment of the biassing
means in the third embodiment of the switch means according to the invention;
Fig. 18 is a partly cut-away rear end view similar to that of Fig. 15, but with the
third embodiment of the biassing means shown in Fig. 17 in neutral position;
Fig. 19 is a view similar to Fig. 18, but with the parts in an activating position;
Fig. 20 is an axial-sectional view of a fourth embodiment of the switch means according
to the invention;
Fig. 21 is a cross sectional view, taken in a plane indicated by XXI - XXI in Fig.
20, with the parts in neutral position;
Fig. 22 is a view similar to that of Fig. 21, but with the parts in an activating
position;
Fig. 23 is a lateral view of an embodiment of a power tool apparatus according to
the invention held by an operator's hand activating an embodiment of the switch means
as shown in Figures 20 to 22;
Fig. 24 shows in axial-sectional view the same embodiment of the power tool apparatus
shown in Fig. 1, but without inserted shaft means of the third insert unit (8C) in
said building block, and, attached to the first building block, a first embodiment
of a handle unit according to the invention;
Fig. 25 is a partial cross sectional view of the handle unit taken in a plane indicated
by XXV - XXV in Fig. 24;
Fig. 26 is a rear end view of the upper rearward part of the handle unit shown in
Fig. 24;
Fig. 27 is a side view of the embodiment of the power tool apparatus shown in Fig.
1, but bearing a second embodiment of the handle unit attached thereto as well as
modified switch-actuating means therein;
Fig. 28 is a cross sectional view of the last-mentioned power tool apparatus and handle
unit, taken in a plane indicated by XXVIII - XXVIII in Fig. 30, infra;
Fig. 29 is a side view of the embodiment of the power tool apparatus shown in Fig.
1, but bearing a third embodiment of the handle unit and switch actuating means therein;
Fig. 30 is a cross-sectional view of the embodiment of the last-mentioned power tool
apparatus taken in a plane indicated by XXX - XXX in Fig. 22;
Fig. 31 is an axial sectional view of a fifth embodiment of switch means according
to the invention with the parts in neutral position;
Fig. 32 is a view similar to Fig. 31, but with the parts in an activating position;
Fig. 33 is a side view of a rearward portion of a power tool apparatus according ot
the invention held in an operator's hand, which hand actuates the switch means illustrated
in Figures 31 and 32;
Fig. 34 shows in a lateral, partially axially sectional view a drilling tool having
connecting means according to the invention;
Fig. 35 shows in a perspective view the connecting socket body being a part of the
connecting means shown in Fig. 34;
Fig. 36 shows in a perspective view a socket tool adapted for tightening and for
loosening nuts, having similar connecting means as shown in Fig. 34;
Fig. 37 shows in an axially sectional view an angle sander and cutting unit having
similar connecting means as are shown in Fig. 34;
Fig. 38 is a partially axially sectional view of a hedgerow-cutting tool having a
basic construction in common with the tool illustrated in Fig. 37, but with modified
connecting means;
Fig. 39 is a bottom view of the hedgerow-cutting tool per se as shown in Fig. 38;
Fig. 40 is a rear end view of the tool shown in Fig. 38;
Fig. 41 is a partially axially sectional view of a straight-blade saw unit equipped
with connecting means similar to those shown in Fig. 34;
Fig. 42 is a front view of the straight-blade saw unit shown in Fig. 41, after removal
of a protective shield; and
Fig. 43 shows items of a kit according to the invention, comprising the power tool
apparatus according to the invention, a sanding and cutting tool adapted for attachment
to the said apparatus and being similar to the tool shown in Fig. 37, as well as a
portable battery and an electric cord therefor.
DETAILED DESCRIPTION OF THE EMBODIMENTS SHOWN IN THE DRAWINGS
[0068] A first embodiment of the power tool apparatus according to the invention of particularly
uncomplicated structure is shown in Fig. 1. This embodiment is built from an enveloping
shell 1 having a central longitudinal axis CL and containing, integral with the shell
1, a transverse wall 2. This transverse wall 2 divides the shell interior into a rearward
chamber 3, having an open rear end 3a, and a forward chamber 4 having an open front
end 4a of the shell 1. In the rearward shell chamber 3 there is housed a speed-reducing
unit 13 which will be described more in detail below. The open shell rear end 3a
is closed by a second, transverse closing wall 6, which has an opening 6a. Likewise,
the first transverse wall 2 has an opening 2a therein.
[0069] Between the two transverse, upright walls 2 and 6 enclosing the rearward shell chamber
3, the speed-reducing unit 13 is mounted as described hereinafter.
[0070] A driving shaft 14 extends through the wall opening 6a into the rearward shell chamber
3, and bears at its end a pinion 73; and a driven shaft 7 of the speed-reducing unit
13 extends through the wall opening 2a into the forward shell chamber 4.
[0071] The shell 1 and the speed-reducing unit 13 therein constitute a first building block
of the power tool apparatus according to the invention. A second building block is
constituted by a motor unit 11, to be described in detail hereinafter, which unit
is mounted fixedly on the outside of the second transverse, closing wall 6.
[0072] A third building block comprises an insertable bearing-wall 8 which has a central
opening 8a in which there is fitted a bearing 9. This bearing 9 is preferably a bronze
bearing or constituted by a sintered bushing such as a carbide bearing or the like,
in which there is supported a power-transmitting unit 10 which, in the simple construction
of the embodiment of Fig. 1, is constituted solely by an intermediary shaft 5, one
end 7a of which is connected, for instance by a square head joint, for rotation with
the driven shaft 7 near the transverse wall 2, and which extends through the forward
shell chamber 3 and is supported in the bearing 9 in the bearing wall 8. From the
latter the intermediary shaft 5 protrudes with its square-head front end 5a to outside
the bearing-wall 8. The latter, the bearing 9 and the shaft 5 thus can be assembled
to constitute the entire third building block, and can be inserted into the forward
shell chamber 3 via the open front end 4a and can be guided in the bearing 9 so that
the rearward end 7a is brought automatically into engagement with the forward square-head
end of the driven shaft 7 which end extends out of the opening 2a into the forward
shell chamber 4.
[0073] It is thus easy for an operator of the power tool apparatus according to the invention,
for instance a construction worker doing heavy duty work e.g. on a several storeys-high
scaffolding, who holds the enveloping shell 1 and the motor unit 11 thereon with one
hand, to remove the entire inset unit comprising the bearing-wall 8, by detaching
the latter from the front end 4a of the shell 1 with his other hand, depositing it
in a kit box, taking out a different inset unit, which also comprises a bearing-wall
8, and reintroducing the new unit into the forward chamber 4 of the power tool apparatus
via the open front end 4a of the shell 1.
[0074] Fastening means holding the bearing wall 8 in the shell front end 4a are of conventional
snap-in, screw, or bolt-and-nut type and have been omitted from the figures of the
drawing for the sake of clarity. Such fastening means are also used for mounting the
motor unit on the transverse rear wall 6, and elsewhere in the apparatus as mentioned
further below.
[0075] In the embodiment shown in Fig. 2, parts identical with those of Fig. 1 bear the
same reference numerals. The inset building block 10 is constituted by an impact-generating
unit shown in more detail in Figures 2a and 2b.
[0076] There shall now be described in more detail the speed-reducing unit 13 and the impact-generating
unit 10.
[0077] The following terms used in this description as well as in the appended claims such
as "upper", "lower", "downward", etc. have reference to the respective positions as
shown in the drawings. Moreover, the terms "front" and "forward", "rear" and "rearward"
have reference to the apparatus as seen by the user holding it in hand, with the motor
unit at the rearward and the inset unit at the front end.
[0078] The preferred type of speed-reducing unit 13 shown in Fig. 1 comprises a train of
spur gears consisting of a small driving gear 73 mounted on the driving motor shaft
14 for rotation therewith. I have found it advantageous to use a gear having a diameter
of 14 mm and bearing twelve cogs or teeth. This gear 73 engages another larger spur
gear 74 which is mounted fixedly on a gear shaft 75 being rotatably mounted in upright
casing walls 2 and 6. The spur gear 74 has advantageously a diameter of 44 mm and
42 cogs. On the same shaft 75 there is fixedly mounted, on the side of the gear 74
turned away from the motor unit 11, a smaller spur gear 76 having a diameter of 18
mm and 16 cogs. This gear 76 which rotates, of course, at the same speed as the gear
74 engages a larger spur gear 77 which is mounted on a driven shaft 7 having a separable
forward extension 7a constituting the aforesaid intermediary shaft and being rotatably
supported in the frontal upright end wall 8 of the apparatus shell 1. The spur gear
77 has a diameter of 34 mm and bears 32 cogs. This results in a transmission ratio
of the speed of the driving shaft 14 to that of the driven shaft of 7:1. The speed
of the driven shaft is then 1957 r.p.m. if that of the driven shaft under full load
is 13700 r.p.m.
[0079] The desired objects of the invention are also fulfilled if the following gear trains
are used as speed- reducing unit 13; based on a full load motor speed of

or similar transmission ratioes within the stated range.
[0080] The speed ratio of 7:1 is particularly preferred because it permits greater flexibility
for use of the same apparatus as a hobby tool apparatus as shall be explained further
below. Speed ratios above 12:1 and below 7:1 have been found unsatisfactory, because
the driven shaft then either rotates too fast or too slow for the purpose set forth
above, as shall be explained below.
[0081] In its forward portion the driven shaft 7 bears forward of its ball, roller or sintered
metal bearing 7a in upright wall 2 an impact-generating unit 10. (Fig. 2a)
[0082] The impact-generating unit 10 comprises a claw coupling comprising two clutch halves
of which the rearward half 79 is firmly mounted, for instance by means of a key 78c,
on the driven shaft 78a, while the forward "hammer drum" 80 is mounted axially shiftable
on the same shaft and is urged away from the rearward half 79 of the coupling by means
of a strong axially acting pressure spring 81. The spring is housed in the hollow
interior formed by cavities 79b and 80b in the adjacent portions of the two clutch
halves 79 and 80 and has its one end supported against the inner face of the rear
end wall 79a of the clutch half 79 and the other spring end is supported against the
inner face of the forward end wall 80a of the clutch half 80.
[0083] The two clutch halves 79 and 80 remain in coupled engagement with each other at all
times so as to rotate in unison about the shaft 78a regardless of the position of
the clutch half or "hammer drum" 80 on this shaft; to this end claws 83 of the rearward
clutch half 79 engage claws 84 of the forward clutch half at all times.
[0084] Between the forward frontal face 82 of the forward clutch half 80 and the frontal
upright wall 8 there is mounted, with its shaft 89, an impact anvil 85 bearing on
its rearward disc face 85a (see Fig. 2a) a diametrically extending rib 86 having sloped
flanks 86a and 86b whose angles of inclination converge from the disc face 85a toward
the clutch half 80. These flanks 86a and 86b can be abutted against by two noses or
hammers 87 and 88 which protrude from the frontal face 82 of the clutch half 80 and
are urged by the spring 81 toward the face 85a of the impact anvil 85. Each of these
two noses also has sloped flanks 87a, 87b and 88a, 88b on its axially extending lateral
walls which sloped flanks abut against the sloped flanks 86a, 86b of the rib 86. The
nose flanks 87a, 87b and 88a, 88b have been indicated by dashed lines in Fig. 2b because
the cross sectional plate IIB-IIB extends through the untapered foot portions of the
hammers 87 and 88, respectively, and the angles of inclination of flanks in each of
these pairs converge toward the face 85a of the impact anvil 85.
[0085] The impact disc shaft 89 is supported in a pressed-in gland or a ball roller, or
sintered metal bush bearing 9 in the forward upright end wall 8 of the apparatus shell
1 and protrudes from the end wall 8 with a square head end 95. A tool socket, or for
instance, a wrench having a suitable cavity, for instance of hexagonal cross section
whose diameter corresponds to that of a screw, nut or bolt to be loosened or tightened,
can be firmly attached to the square head end 95 for rotation with the latter.
[0086] The rearward end of the disc shaft 89 ends flush with the top face of the disc rib
86 and contains a cavity 89a preferably extending into the shaft zone inside the bearing
9, in which cavity 89a there is loosely supported the forward free end of the driven
shaft 78a.
[0087] The operation of the impact unit 10 when loosening a screw nut or bolt having a right
hand thread is the following: The tool is placed over the screw nut or bolt. Initially,
the spring 81 shifts the loose clutch half 80 in forward direction and the noses 87
and 88 abut with their frontal faces against the rear disc face 85a. When the motor
unit 11 is switched on, the driven shaft 7 + 5 rotates in the direction of the arrow
L (Fig. 2b ) together with the clutch half 79.
[0088] As the claws 79b and 80b remain in engagement with one another even when the clutch
half 80 is shifted forward, the loosely mounted clutch half 80 is taken along and
rotates in unison with the clutch half 79. Thereby, the clutch half nose 87 abuts
with its leading sloped flank 87a (Fig. 2b ) against the sloped flank 86a of the disc
rib 86, whereby the former flank "climbs upward" on the latter, while the same occurs
also with leading flank 88a of the clutch half nose 88 abutting against the sloped
flank 86b of the rib 86. Thereby the loose hammer drum 80 is shifted slightly in rearward
direction, with corresponding compression of the impact drum spring 81 until the
hammers 87 and 88 can pass over the rib 86 of the impact disc 85. As rotation of
the clutch halves 79 and 80 continues, the spring 81 urges them apart again so that
the hammers 87 and 88 are shifted forward, together with their hammer drum 80, toward
the impact disc 85. At each revolution of the driven shaft 7 the hammers 87 and 88
hit against the disc rib 86 until the screw nut or bolt has become loose enough, under
these impacts occurring at a frequency of about 2000 per minute, to follow the rotary
movement of the tool on the shaft 89, taking along the impact anvil 85. As soon as
this occurs, the anvil 85 rotates in unison with the clutch halves 80 and 79, the
impacts cease, and the nut or bolt can be completely removed.
[0089] Operation in the opposite sense will lead to a tightening of the screw, nut or bolt
(arrow T in Fig. 2b). If the motor runs at significantly less speed, or the speed
reduction is greater than 12:1, e.g. if the motor speed under load drops to 10 000
r.p.m. or lower, for instance due to an automobile battery whose operational voltage
has dropped to 10 volts or lower, or if the speed reduction ratio is 14:1 instead
of 12:1, the corresponding lower number of impacts has been found insufficient to
loosen a severely jammed or seized screw. A drop in the impact frequency will also
prevent the hammers 87 and 88 from overcoming the bias of the spring 81.
[0090] Surprisingly, I have also found that a motor speed of, e.g. 35000 r.p.m., corresponding
to a driven shaft speed of 5000 r.p.m. when the speed reduction ratio is 7:1, or even
of 25 000 r.p.m., if the speed reduction ratio is 5:1 thus yielding a driven shaft
speed of about 5000 r.p.m., may also fail to loosen severely jammed screws. It appears
that the impact exerted on the disc shaft 89 and on the tool thereon, will then be
too weak, as the hammers 87 and 88 will skip over the disc rib 86 and will fail to
produce a strong, abrupt impact. Moreover, at higher speeds due to a transmission
ratio smaller than 7:1, the same load will impact too much braking power to the motor
and too much lever force will be lost in the gear transmission.
[0091] When operating the motor with a 24 volt-automobile battery, a motor speed of 27000
r.p.m. can be obtained. In this case the speed of the driven shaft 7 and the number
of impacts on the disc rib 86 will rise to almost 4000 revolutions or impacts per
minute, respectively. The same number of impacts can also be attained when the speed
of the driven shaft 86 is 2000 r.p.m. and there are four noses provided, equidistantly
distributed about the periphery of the frontal face 82 of the loose hammer drum 80.
Depending on the degree of jamming or seizing of the screw, nut or bolt to be loosened,
this higher number of impacts may work or fail.
[0092] Operations of the impact wrench shown in the embodiment of Figures 1 to 2b with
direct current from a 12 Volt battery (operational voltage 10.5 to 14 volts) affording
a motor speed of 13750 to 15000 r.p.m. and a transmission ratio of 7:1 affording
a speed of the driven shaft 7 of 2000 r.p.m. and the same number of impacts per minute
has been found to be most satisfactory.
[0093] In Fig. 3 there is shown, inserted in the same first building block as in Figures
1 and 2, a further embodiment of the third, i.e. the inset building block, which comprises
the intermediate shaft 5 as well as a fan 15. During operation, this fan 15 can generate
an air current through the entire interior of the enveloping shell 1; in this case
air passages 16 are provided axially through the walls 2, 6 and 8 of the apparatus
housing. Depending on the sense of rotation of the shaft 5, the fan 15 can blow air
on to a tool attached to the square-head 95 of the driven shaft 5, or it can blow
air into the motor unit 11 and cool the electrical motor therein.
[0094] The second rearward building block consists essentially of a motor unit 11 which
comprises a motor and switch means 12 therefor.
[0095] The motor in the rearward building block is preferably an electric motor, and, for
heavy duty work, when an automobile battery or portable nickel-cadmium battery are
available, and also when the operator uses a kit according to the invention, which
may contain the portable battery, an electric direct current motor has been found
to be more satisfactory than any other type. The motor data given hereinafter by
way of example are those of a motor which has proven to be most successful in heavy
duty work as well as in all kinds of lighter work.
[0096] The motor unit 11 is shown in more detail in Figs.4 and 5. The unit comprises an
electric D.C. motor which comprises a generally drum-shaped armature 20 composed of
forty lamellae 21, each consisting of about .65 mm thick sheet iron plates having
an external diameter D
e of 32 mm, which are arranged in parallel to form a package having an overall length
L of 26 mm (Fig. 4 ). Each lamella 21 has in its outer annular zone twelve radial
lamella cutouts 22, and the internal diameter D
i of the lamella between the deepest ends of two diametrically opposite cutouts 22
is 16.7 mm. The lamellae 21 in the stack thereof forming the armature 20 are superimposed
upon each other so that the cutouts register with one another and form twelve axially
extending channels 26 in the external surface of the armature 20. Each of these channels
houses portions, shown in cross section only in a single cutout 22 for the sake of
clarity, of a hard copper wire 23. This copper wire has a diameter of .56 mm. Windings
of this copper wire are wound about the armature in loops, so that 32 wire portions
fill each of the channels 26 , each loop consisting of two such portions and having
a length of about 60 to 70 mm, i.e. a bit more than double the length of the armature.
The wire windings are formed by pieces of wire having a length of about one meter,
so that each such piece of wire can be wound in about sixteen loops from the rear
end of the motor about the armature 20 through the channels 26 of the latter. The
two free ends of each piece of wire are soldered to different collector segments
24 of a commutator 25 which is mounted fixedly on a driving shaft 14 in common with
the armature 20 for rotation in unison therewith.
[0097] As there are twelve pieces of wire having a total of 24 free wire ends, twelve collector
segments 24 are provided in the commutator 25, the whole constituting a two-pole
drum-winding having a total length of twelve meters of wire of about 12 meters. The
total number of wire portions in the twelve channels which should be shown in Fig.
5 would be 384.
[0098] The driving shaft 14 is supported in roller or bronze bearings 31 which are mounted
respectively in the frontal end wall 32 and the rear end wall 33 of a motor housing
30. The latter is in turn held firmly in the upright wall 6 of the apparatus shell
1, as shown in Fig. 1.
[0099] The housing further comprises a cylindrical hull 34 which bears in its interior firmly
attached to its inside wall the north pole shoe 17 and the south pole shoe 18 of a
permanent magnet 19 of magnetic iron which have a length, in axial direction, of 31
mm and a radial thickness of 5.5 mm. The general arrangement of permanent magnet and
armature is well known and illustrated in Fig. 150 of chapter "Gleichstrommaschinen"
in "Elektrotechnik" by A. Däschler, a text-book published in 1968 by Verlag Aargauer
Tagblatt AG in Aarau, Switzerland. However, as indicated in Fig. 152 of the same publication,
the armature diameter is expected to be about 600 mm instead of the 32 mm of our novel
D.C. motor. While the D.C. motor, according to Fig. 152 of the Däschler-textbook affords
280 kilowatts (kW) at 1470 r.p.m., our motor affords under load 0.6 kW at about 3700
r.p.m.
[0100] Electric motors of electric power-operated impact wrenches which are presently available
in the market and are capable of loosening jammed or seized nuts or threaded bolts
of automobile wheels for the purpose of changing automobile tyres must derive their
power from an electric main, e.g. of 220 to 240 volts of A.C.
[0101] Several impact wrenches of this type have been described under the heading "Schlagschrauber"
in the publication "Bosch Elektrowerkzeuge, Programm 1980/81 in August 1980, by Robert
Bosch GmbH, D-7022 Leinfelden-Echterdingen, Germany. Depending on the size of the
bolts to be loosened, e.g. of 16 mm diameter for passenger car wheels, the motor operates
under full load with a speed of 1000 r.p.m., it has a power input of 320 Watt (about
1.5 Amp.) and a power output of 165 Watt and a tightening torque of 180 Newtonmeters
(Nm), the wrench has a weight of 3 kilograms.
[0102] For heavier bolts of 22 mm diameter, the wrench is equipped with a motor operating
at 725 r.p.m. under full load, with a power input of 420 Watt, (about 1.9 amperes)
a power output of 200 Watt, and a tightening torque of 300 Nm; the wrench weighs about
5.3 kg.
[0103] Screws having a diameter of 27 mm can be loosened with a wrench whose motor penetrates
at a speed of 540 r.p.m. under full load, with an input of 620 Watt (2.8 amperes),
an output of 360 Watt, and a tightening torque of 800 Nm; this wrench weighs 8.3 kg.
[0104] In contrast thereto, the above-described electric motor in our preferred embodiment
operates at a speed under full load of 2000 to 2800 r.p.m., with a power input of
about 300 to 450 Watt (25 to 40 amperes) and a power output of about 250 Watt, and
a loosening torque up to 800 Nm (25 amperes and higher); the apparatus has a weight
of maximally 3 kg, and even less, while it is fed by a D.C. of 12 volts (operational
voltage of about 10 to 14 volts) as supplied by a common automobile battery. When
connected to a heavy automobile battery of 24 volts, it operates under full load with
a speed of 4000 r.p.m.
[0105] A speed is measured under full load when the tool socket is momentarily blocked and
the impact mass hits upon the impact abutment in the impact unit. In this case the
speed of Motor A drops from the idling speed of 15 000 r.p.m. to a speed under full
load of 2800 r.p.m. corresponding to a speed of the driven shaft with continous impacts
of 400 r.p.m. when the Motor A is used in an impact wrench according to the invention
having a speed reduction ratio of 7:1, and to a speed of 235 r.p.m. when the impact
wrench has a speed reduction ratio of 235 r.p.m. The motor then draws a current of
about 75 amperes from the 12 volt battery, i.e. a power of about 800 watts, when loosening
exessively tightened bolts or nuts of automobile wheeles. The power input required
by the motor when the tool socket and the driven shaft idle and the motor shaft rotates
at a speed of 14 000 r.p.m., is about 18 watt, corresponding to about 7 amperes when
the battery has a potential of about 11.4 volts, when the speed reducing ratio in
the impact wrench is 12:1. When tis ratio is 7:1 the idling speed of the motor shaft
was found to be 12 600 r.p.m., the power consumtion was 74 watts, corresponding 6.4
amperes of current drawn from a battery having a potential of 11.56 volts.
[0106] Old batteries having no longer the full potential of 12 volts were used in order
to test the capabilites of the impact wrench according to the invention under less
than optimal conditions.
[0107] In the following table there are given data for two preferred embodiments A and B
of the electric motor to be used in the power tool apparatus of the invention:

[0108] The fully satisfactory results obtained with the preferred embodiment of the power
wrench according to the invention are particularly unexpected as it would have been
obvious to provide a slower motor of less full load speed and higher power input and
output the severer the jamming or seizing of the screw to be loosened (see the Bosch
motors described above).
[0109] I have discovered unexpectedly that the opposite is true and that a "weaker" motor
operating at higher speed under full load can do the same job successfully even though
it is fed with direct electric current of low voltage, e.g., 12 or 24 volts of an
automobile battery.
[0110] The small size, low weight and high speed of the above-described motor used in the
preferred impact wrench according to the invention is comparable only to those of
compressed air motors as they are known to be used in Atlas Copco wrenches (see the
publication "Schrauber" by Atlas Copco Aktiebolag, Nacka, Sweden, in November 1971).
However, these wrenches are destined only for screws having a diameter of about 5
to 8 mm, and are therefore unsuitable for tightening or loosening screws or bolts
of automobile wheels. The same is true for the Mitsubishi hobby impact tool apparatus,
in particular drills, driven by small motors as described hereinbefore.
[0111] In attaining the objects of the invention I have found the following features described
hereinafter to be also cri tical, i.e. the high speed of the weaker motor is only
one of several criteria I had to observe in achieving the above-stated main object.
[0112] Thus, I have found that the speed reduction ratio of the driving to the driven shaft
in the speed reducing unit is highly critical in order to achieve the object of loosening
severely jammed or seized screws, bolts or nuts of the type used for mounting autombile
wheels on their hubs. This speed reduction ratio should be in the range of from about
12:1 to about 7:1, the ratio of 7:1 being the preferred one when the apparatus is
operated with D.C. drawn from a 12 volt-automobile battery.
[0113] In order to obtain a particularly satisfactory operation of the embodiment of the
power tool apparatus shown in Figs. 1 to 3 , it has also been found very advantageous
to avoid voltage losses by providing novel on-off and reversing switch means 12.
[0114] A preferred embodiment of such switch means 12 is illustraded in Figures 4 and 6
. The leads 121 and 122 from the + pole and the - pole, respectively, of a 12 Volt-
or 24 Volt-automobile battery are connected to two contactor pins 41 and 42 which
are mounted inside a rotatable switch cap 40 on a pins-supporting disc 49, being electrically
insulated against the latter by insulating jacket 41a and 42a. The disc 49 is firmly
connected with the switch cap 40, for rotation therewith, by means of one or several
connecting flat-head screw bolts 72 inserted through a hole 72a in the cap bottom
wall 40a and screwed into a threaded bore 72b in the supporting disc 49. The disc
49 is rotatably mounted on a bridge member 43 which is fastened by means of screws
43a on the outside face of the rear end wall 33 of the motor housing 30. The bridge
member 43 has on its side facing away from the rear end wall 33 an outwardly projecting
raised central bridge portion 44 and a central bore 44a therein which registers with
the central bore 49a of the supporting disc 43 and opens at its forward end in the
cavity 43b in the face of the bridge portion 44 turned toward the motor housing rear
end wall 33. A setbolt 46 having a larger diameter bolt head 45, which rests in the
cavity 43b extends through the central bores 44a and 49a and protrudes from the rearward
face of the supporting disc 49 where it is fastened by means of a washer 47 and cotter
pin 48, thus serving as a shaft about which the pins-supporting disc 49 can be rotated
by turning the switch cap 40.
[0115] The pins-supporting disc 49 has a further axial bore 56 which opens out of the inward
face of the disc 49 where the latter abuts against the rearward face 44b of the raised
bridge portion 44. A resting ball 57 is lodged in the bore 56 and is urged into contact
with the rearward bridge portion face 44b by means of a pressure spring 58 also lodged
in the bore 56 and being supported at its other end on the underside of the washer
47.
[0116] Owing to the above-described arrangement, the switch cap 40 is held rotatably at
the rear end of the motor unit 11, with the cap side wall 40a enclosing the rearward
portion of the motor housing 30. Rotation of the cap 40 about the cap shaft 46 is
limited by the stop 67 mounted on the forward face of the pins-supporting disc 49
which abuts, in the position shown in Figures 4 and 6 against a first counter stop
68, in which position pins 41 and 42 are electrically conductive contact, respectively,
with two contactor blades 50 and 51 which the mounted, adjustably in axial direction,
in blade bearing means 52 and 53, respectively, which are of electrically insulating
material. The contactor blades 50 and 51 are in turn electrically conductively connected
via litze (leads) 50a and 51a with the commutator brushes 54 and 55, respectively.
These brushes 54 and 55 are held in brush holders 38 and 39 of electrically insulating
material and slide over the collector segments 24 of the electro motor.
[0117] Direct electric current is supplied to the motor 12 from leads 121 and 122 which
have their one ends connected to the +pole and -pole, respectively, of a direct electric
current source, in particular an automobile battery of 12 volts (Fig.43), while their
other ends are fastened, respectively, to the threaded rearward ends of the contactor
pins 41 and 42 by means of fastening nuts 69 and 69a.
[0118] In the position of the switch cap 40 illustrated in Figures 4 and 6 the collector
segments 24 thus receive direct electric current from lead 121 via contactor pin 41,
contactor blade 50 and collector brush 54, on the one hand, and from lead 122 via
contactor pin 42, contactor blade 51 and collector brush 55, while upon turning the
switch cap by 90° counterclockwise (when looking at the rear end 33 of the motor housing
30 in axial direction), i.e., in the sense indicated by the arrow CC in Fig. 6. When
the switch cap 40 has been turned through an angle of 90°, the bore 56 of the supporting
disc 49 registers with a small recess or indentation 59 in the rearward bridge portion
face 44b, which recess is large enough to receive half of the ball 57 therein, thus
providing a light arresting position for the switch cap 40, indicating that the switch
is in OFF-position.
[0119] By further rotating the switch cap 40 counterclockwise, the ball 57 is forced out
of the recess 59 against the bias of spring 58 until the stop 67 on the disc 49 abuts
against a second counter stop 68a thus assuming the position indicated by 67ʹ in Fig.
6.
[0120] This position of the switch cap 40, the position of the contactor pins 41 and 42
is exchanged, pin 41 now making contact with the contactor blade 51, while the pin
42 makes contact with the contactor blade 50. The motor thus receives direct electric
current flowing in the opposite direction from the leads 121 and 122 connected to
the automobile battery and will accordingly rotate in the opposite sense.
[0121] This means that, if the motor turned clockwise, corresponding to the sense of the
arrow T in Fig. 2b when the contactor pins and blades made contact in the first described
manner, then, with contact established in the last described manner, the motor of
unit 11 will reversed, i.e. it will rotate counterclockwise, in the sense of arrow
L in Fig. 2b.
[0122] The embodiment of an impact wrench apparatus shown in Figures 1 to 6 can be easily
converted to a hobby tool. This conversion is possible in two ways. According to one
mode of conversion, a connecting bolt 91 can be inserted through a transverse bore
92 in the rib 86 of the impact disc 85, which bolt 91 will protrude into a corresponding
bore 93 in at least one of the noses 87 and 88, thus eliminating the impact effect
and causing the impact disc 85 to rotate in unison with the clutch halves 79 and 80.
[0123] In the embodiment of the motor and the on-off and reversing switch means shown in
Figs. 7 and 8., like parts having identical functions are designated by like numerals
as in the preceding Figures.
[0124] This embodiment is characterized by a particularly simple, sturdy arrangement of
the current-conducting parts of the rear portion of the armature and of the switch
means. The cap member 140 has a closing wall 149 extending radially with regard to
the rotor axis, a lateral cylindrical wall 140a and, on the outer face 149a of the
closing wall 149, a peripheral, inwardly crimped rim 163 surrounding a cavity 161
the bottom of which is constitutes by the outer face 149a of the closing wall 149
and which cavity 161 is open toward the outside at the rear end of the power tool
apparatus.
[0125] The closing wall 149 bears on its inner face 149 b a central pin 146 having a larger
diameter head 145 which is snapped into a corresponding snap-in recess 144 in a socket
143, whereby the cap member 140 is supported for pivotal displacement on the rear
end wall 33 of the motor housing 30. The socket 143 protrudes axially from the rearward
face 33a of the motor housing end wall 33. In the rear end wall 33 there are mounted,
in diametrical arrangement with regard to the rotor axis, and in blade bearing sleeves
152 and 153, two contactor blades 150 and 151 which extend into the interior of the
motor housing 30 and are electrically conductively connected to the brushes 54 and
55, respectively.
[0126] In this embodiment, the use of litzes 50a and 51a has thus been eliminated, thereby
reducing the possibility of power losses. At their free ends the contactor blades
150 and 151 bear resilient, inwardly crimped contact spring parts 150a and 151a which
are contacted by contactor pins 141 and 142 which are snugly lodged in corresponding
bores or ducts 141a and 142a, respectively, in the closing wall 149 of the cap member
140 and protrude through this closing wall 149 axially into the interspace 133 between
the inner face 149b of the closing cap wall 149 and the rearward face 33a of the rearward
wall 33. The contactor pins 141 and 142 are firmly embedded in a plug body 169 and
protrude from the inner face 169a thereof, while leads 121 and 122, which are connectable
to the minus and plus terminals of an automobile battery, have their opposite ends
likewise embedded in the plug body 169 and have their insulation-free cable ends firmly
inserted in the contactor pins 141 and 142 respectively. The plug body 169 is inserted
firmly into the cavity 161 and abuts with its frontal face 169a against the outer
face 149a of the closing cap wall 149. The plug body 169 is held firmly in the cavity
161 by means of a laterally projecting annular flange part 162 about the frontal face
169a of the plug body 169, which flange 162 is snapped-in and held in position by
the inwardly projecting annular rim 163 of the cap member 140.
[0127] In the periphery of the motor housing rear end wall 33 there is provided a flat indentation
159 which is engaged by a spring tip 157 being mounted at the free end of a small
blade spring 158 which urges the tip 157 into engagement with the indentation 159.
[0128] This engagement of the spring tip 157 of the indentation 159 is shown in Figures
7 and 8 . In this position of all parts of the motor housing rear end wall and switch
means relative to each other, the motor will run in a determined sense of rotation,
when the leads 121 and 122 are pluged into the minus and plus pole, respectively,
of the automobile battery. Current will then flow from the lead 121 through the contactor
pin 141, the contactor blade 151 and the brush 54 to the collector segments 24 and
the windings 23 of the armature 20.
[0129] When the cap member 140 together with the plug body 169 therein and together with
the contactor pins 141 and 142 is pivoted about the axis of its central pivot 146
in the socket 143, the spring tip 157 leaves the indentation 159 and rotation of the
cap member 140 is continued until the spring tip 157 enters a next following indentation
160. This may be noticed by a click audible to the user. In this position, both contactor
pins 141 and 142 have broken contact with contactor blades 150 and 151, and no current
will flow from the automobile battery to the motor.
[0130] Upon further pivoting of the cap member 140 about the axis of its central pin 146
in the same sense of rotation, the spring tip 157 will slide on the peripheral surface
of the motor housing rear end wall 33 until it enters, preferably with a click into
a third indentation (not shown) in which the contactor pin 141 makes contact with
a contactor blade 151, while the contactor pin 142 makes contact with the contactor
blade 150. Thereby, current will flow from the negative pole of the automobile battery
to the brush 55 and from this brush into the windings 23 of the armature 20 and from
the brush 54 back to the plus pole of the battery wire lead 122 and the motor will
run in the reverse sense of rotation.
[0131] A third embodiment of the switch means according to the invention is illustrated
schematically in Figures 9 to 13.
[0132] On the rear end wall 33 of the motor housing there is mounted rigidly by conventional
fastening means (not shown) a stationary mounting or switch base member 60, of electrically
insulating material, which is cup-shaped having a cavity 60a from the center of the
bottom face 60b of which there projects axially a stem 61. Stationary contactors 50
and 51 are mounted in the base member 60 and connected by litzes 50a and 51a with
the motor brushes in the same manner as in the preceding switch embodiments.
[0133] A supporting member 26 which bears the shiftable contactor elements 35 and 36 is
pivotally mounted on the stem 61 which latter projects into a dome part 27 of the
supporting member 26 by way of a central dome opening. A screw 29 is inserted into
a threaded axial bore of the stem 61 and holds a biassing spring 64 in place on the
stem. This spring 64 urges the supporting member 26 toward the base member 60.
[0134] Preferably, the entire supporting member 26 or at least its annular inside face 26a
is of electrically insulating material. On this inside face 26a, there are mounted
the two shiftable contactor elements 35 and 36, each of which is of curved configuration,
covering an arc of about 120 degrees about a central switch axis CS which is normal
to the base member 60 and the supporting member 26.
[0135] A cap member 40 covers the entire switch and has a cap end wall 40a on which the
supporting member 26 is mounted fixedly. Turning the cap member by hand will therefore
also turn the supporting member 26 relative to the base member 60 about the pivot
constituted by the stem 61.
[0136] Such pivoting of the cap member 40 and the supporting member 26 therein about a small
angle of a few, e.g. 15 to 45 degrees to the left (arrow L) will cause a contact face
35a at the one end of the contactor member 35 to slide on to the frontal face 51b
of the fixed contactor 51, while the diagonally opposite contact face 36a will slide
on to the frontal face 50b of the fixed contactor 50. The biassing spring 28 pulls
the two faces 35a and 36a against the faces 51b and 50b, respectively, thereby causing
a secure electrical circuit to be made from a source of direct electrical current
via the plug 100 whose prongs 97 and 98 are inserted into throughholes 101 and 102
in the cap member 40 and throughholes 101a and 102a in the supporting member 26 which
throughholes register respectively with one another. The prongs 97 and 99 make electrical
contact with the corresponding cavities or bores 35a and 36a in the central regions
of arc-shaped contactor elements 35 and 36.
[0137] In order to facilitate sliding of the ends of contact elements 35 and 36 on to the
contact faces 50b and 51b, respectively, one or both of the contact faces of the shiftable
and fixed contactors can be slanted or have beveled or curbed edges, as indicated
in Fig. 14.
[0138] When the cap member 40 and supporting member 26 are pivoted together to the right
(arrow R in Figures 10 and 12), the contactor elements 35 and 36 will slide with their
opposite ends 35b and 36a, respectively, on to the contact faces 50b and 51b, and
the motor of the motor unit 11 will run in the opposite sense of rotation.
[0139] After contact has been made by the switch means 12 in the above-described manner
and the operator ceases turning the cap member 40, a restoring spring 28 (Figures
9 and 10), whose legs 28a and 28b abut against stops 62 and 63 which are integral
with the base member 60, will come into action. When the cap member 40 is pivoted
to the left, the spring leg 28a of the restoring coil spring 28 is held in place by
the stop 62 and the spring 28 is tensioned. When turning force on the cap member 40
ceases, the restoring spring 28 will pull the cap member 40 back from the activating
position shown in Fig. 12 to the neutral position shown in Fig. 10.
[0140] The above-described biassing and restoring spring means can also be replaced by other,
less expensive means. Thus, in Fig. 14, the biassing of the supporting member 26 toward
the base member 65 is achieved by a plate spring 104 which is lodged in an inner cavity
66a, opening toward the motor housing end wall 33, of the base member 65, and is fastened
at its center to the free end of a stem 99 of hexagonal, elongated cross sectional
area. This stem 99 projects from the center of the supporting member 26 and extends
through a recess 66b in the face of the base member 65, which is turned toward the
supporting member 26, and through a central throughhole 66 in a separating wall part
65a of the base member 65, which wall part 65a separates the cavity 66a from the recess
66b.
[0141] The hexagonal column representing the stem 99 comprises two opposite broad flanks,and
adjoining the two long edges of each of these broad flanks are two pairs of narrow
flanks of which each pair has a common edge. The distance between the two broad flanks
is considerably shorter than the distances between diagonally opposite narrow flanks.
Two elastically resilient blades 107 and 108, made for instance from pieces of flat
clock-spring steel, lie flat and straight against the two broad flanks of the stem
99. When the cap member 40 and together therewith the supporting member 26 and the
stem 99 thereon are turned by an angle of, for instance, 30°, as shown in Fig. 16,
the blades 107 and 108 are spread apart and when turning force is no longer applied
to the cap member 40, the steel blades 107 and 108 will restore the stem 99 and the
other parts connected therewith to the neutral position shown in Fig. 15.
[0142] In the embodiment of restoring means shown in Figures 17 to 19, the restoring elastically
resilient element is an elongated plate member 199 which is integral with the supporting
member 26. The plate member 199 is mounted at at the longitudinal edges of two elastically
deformable portions 201 and 202 thereof in a rigid cage 103 which is in turn mounted
stationary on the face 60b, turned toward the supporting member 26, of a base member
60.
[0143] Turning of the cap member 40 into an activating position will cause a deformation
of the plate member 199, as shown in Fig. 19, generating retoring bias therein while
release of the cap member will cause the plate member 199 to straighten out and to
return the entire assembly of the shiftable contactor elements 35 and 36, the supporting
member 26 and the cap member 40, to the neutral circuit-breaking position shown
in Fig. 18.
[0144] Instead of activating the switch means by having the supporting member 26 mounted
fast in the cap member 40 for rotation therewith, a cap member 110 can also be connected
rigidly with the rearward wall 6 of the first building block, and the supporting member
can be loosely surrounted by the cap member 110 and be mounted pivotably on the protruding
base member sleeve (61) as shown in Fig. 13.
[0145] In this case turning of the supporting member 26 and activation of the electrical
circuit is effected with the aid of a push button lever 109 which protrudes tangentially
from a window 112 in the stationary cap member 110 and is integral with the rim 111
of the supporting member 26 (see also Fig. 9). The lever 109 protrudes through a window
112 in the stationary cap member 110. This push-button equipped embodiment of the
switch means according to the invention is shown in Figures 20 to 23.
[0146] Figures 20 and 21 thereof show the switch means in neutral position, Fig. 22 shows
the push-button lever 109 in downwardly swivelled position, whereby the supporting
member has been turned by an angle of about 30 degrees, and Fig. 23 shows how the
operator can depress the lever 109 with the palm of his hand while holding the power
tool apparatus according to the invention.
[0147] In a kit according to the invention, there can be provided, as an auxiliary item,
a handle part, a preferred embodiment of which is designated by the reference number
120 in Fig. 24.
[0148] This handle part 120 can be fastened rigidly, e.g. by screw bolts 119, on the outside
of the rear end wall 6 of the first building block. A grip member 204 can also be
clamped on to the shell 1.
[0149] Between opposite sidewalls 123 and 124 (Fig. 25) there is mounted a switch of the
type illustrated in Figures 20 to 21. However, the base member 65 is mounted, with
its outer face 65b, not on the outside face of the motor housing end wall 33, but
instead on the inner surface of the sidewall 123, and the supporting member 226 is
pivotally mounted on the base member 65 in the same manner as illustrated in the
case of supporting member 26 in Fig. 14, with the outer face of the supporting member
226 extending parallel with, but slightly spaced from the inner surface of the opposite
sidewall 124 of the handle part 120.
[0150] The prongs 97 and 98 of the plug 100 can be inserted in corresponding sockets 114
and 115 at the downward end 116 of the handle part 120 which sockets are connected
via leads 117 and 118 with the shiftable connector elements 135 and 136.
[0151] The fixed contactors 155 and 156 are connected by means of electrical leads 125 and
126 which extend up to a rear extension 127 of the handle part 120 to surround the
rearward end of the cap member 40 and bear at their other ends prongs 197 and 198.
These prongs are inserted into the throughholes 105,105a and 106,106a in the cap member
40 and the supporting member 26, respectively, (Fig. 14) and are long enough to make
firm contact with the frontal contact faces 50b and 51b of the stationary contactors
50 and 51, thereby holding the cap member 40 and the supporting member 26 stationary
relative to the stationary base member 65.
[0152] The supporting member 226 bears tangentially disposed actuating levers 128 and 129
which protrude from the interior of the handle part 120 through windows 112a and
112b in a front wall 131 of the handle part 120.
[0153] Depression of one of the actuating levers energizes the motor in the housing 30 in
one sense of rotation, de pression of the other lever energizes the motor for rotation
in the opposite sense.
[0154] The reference numeral 200 designates a rotary cutting tool attached to the front
end of the power tool apparatus, which tool will be described further below in connection
with Fig. 37.
[0155] In Figures 27 to 30 there are illustrated two versions of a simple mechanism for
turning the cap member 40 when a different embodiment of the handle part is used,
and thereby activating the switch means 12 inside the cap member, while no secondary
switch means are provided in the handle part 130. This handle part does not comprise
a rearward extension 127.
[0156] In the actuating mechanism illustrated in Figures 27 and 28, the handle part 130
is attached firmly to the rear end wall 6 of the enveloping shell 1 of the first building
block and supports the second building block in a manner such that the cap member
40 can be turned by the operator relative to the shell 1 and handle part 130, in order
to actuate the switch means 12 comprising preferably the parts illustrated in Fig.
14.
[0157] The cap member 130 bears at its undersie a curved, peripherally extending rack 132
in which a pawl 134 is engaged. The pawl 134 is pivotally mounted on a pivot pin
137a fixed in the rearwall 131a of the handle part 130.
[0158] In the front wall 131, there is mounted an actuating peg 147 protruding via an opening
131a with its conically pointed end 147a inwardly into contact with the front side
of a rod-shaped extension 137 of the pawl 134. The flat opposite face 148 of the
peg 147 is mounted on the inside of a deformable circular membrane 138 whose periphery
is firmly attached to the outside of the front wall 131 of the handle part 130.
[0159] When an operator holding the handle part depresses with one finger the actuating
peg 147 inwardly and deflects it slightly either to the right or to the left, as desired,
the conical surface of the peg 147 about its conically pointed tip 147a will press
the pawl-rod 137 correspondingly to one side and the pawl 134 will cause the cap
member 40 to turn correspondingly and cause the switch means 12 to make circuit. In
Fig. 28 the actuating peg 147 has been slightly deflected to the right while depressing
it, so that the pawl 134 is also swivelled to the right and causes the cap member
40 to turn in the sense of the arrow L shown in Fig. 12.
[0160] Restoring means can be provided in the handle part 130 and comprise a restoring spring
28 similar to that shown in Fig. 13.
[0161] In the simpler actuating mechanism shown in Figures 29 and 30, the cap member 40
bears firmly attached on its underside a rod 139 which projects downwardly into the
in terior of the handle part 130. The same peg-and-membrane mechanism as used in
the embodiment of Figures 27 and 28 is also applied in this case. Restoring spring
means are provided in the same manner as in the switch means illustrated in Figures
9 to 13 or 14 to 19 and urge the cap member 40 toward neutral position.
[0162] Another, simplified embodiment of the switch means 12 is illustrated in Figures 31
to 33. In this embodiment, the cap member 40 is fixed on the motor housing 30, and
the fixed contactor 51 extends across an interspace 133a to the cap end wall 40a in
which a throughhole 206 leads to the contactor 51.
[0163] The contactor 50 has a circuit-breaking gap 71 therein, but is otherwise of similar
construction as the contactor 51, and can be connected electrically via a throughhole
205, when the prongs 97 and 98 of the plug 100 are inserted in these throughholes.
In order to make circuit as shown in Fig. 32, a contact pin 164 which is mounted in
a flexible membrane 166, must be depressed by the operator.
[0164] The entire interspace 133a can be filled by a base element 165 which is attached
firmly on the motor housing end wall and the cap end wall 40a.
[0165] In the following Figures 34 to 43, there are illustrated several tools suitable
for being affixed to the front end of the power tool apparatus according to the invention
described hereinbefore. In order to be acceptable as items in the kit according to
the invention, all of these tools require in their construction connecting means adapted
to the aforesaid apparatus front end. The common features of these connecting means
shall now be described in detail.
[0166] The front end of the power tool apparatus comprises the bearing-wall 8 which has
a main wall portion detachably, but rigidly mounted in the open front end 4a of the
enveloping shell 1, the above-mentioned central opening 8a and the bearing 9 in which
there is lodged the forward end of the power-transmitting inset unit 10 lodged in
the forward shell chamber 4, which inset unit comprises a forward shaft end 95, preferably
as a polygonal, in particular a square head end, which shaft end 95 protrudes from
the bearing 9 to the outside.
[0167] Moreover a centering body portion 94 projects forward of the shell front end 4a and
surrounds the bearing 9. The external annular face 96 extending in axial direction
about this forward body portion 94 constitues a cylindrical or slightly frustoconical
centering face.
[0168] Preferably, at the annular zone where the projecting portion 94 merges with the main
body of the bearing-wall 8, there is provided an annular groove 196.
[0169] Fastening means such as screw bolts insertable into corresponding bores in the forward
annular face 8b of the bearing-wall 8 radially outside the body portion 94 thereof,
or clamping means as illustrated in Fig. 42, infra, have been represented schematically
or omitted for the sake of clarity, as the art-skilled are familiar with them.
[0170] The corresponding bores in the connecting sockets of the tools described hereinafter
have been omitted likewise or indicated by dashed and dotted lines, e.g. in Fig. 2.
[0171] The connecting socket unit being a part of the drilling tool shown in Fig. 34 comprises
the connecting socket body 170 having a rearward face 170a and a central cavity 171
therein. The cavity sidewall 172 is cylindrical or slightly conically tapered to widen
outwardly and fit with good centering on to the correspondingly shaped annular face
96 of the bearing-wall body portion 94.
[0172] The socket body 170 has a central axial bore or throughhole 173 which opens to the
rear in the bottom 171a of the cavity 171 and forwardly in a recess 174a in the frontal
face 174 of the socket body 170.
[0173] Into this throughhole 173 there is introduced from the front a connecting shaft piece
175 having a central collar 176 which comes to rest in the recess 174a. At its rearward
end the shaft piece 175 has a rearwardly open cavity 177 of polygonal cross-sectional
area, which is adapted to fit over the polygonal head end 95 of the intermediary shaft
5. Preferably, the head end 95 is a square head end and the cross-sectional area of
the cavity 177 is then also a square one. It is important that the square or the like
polygonal shaft end 95 fits with play into the cavity 177. Thereby, no centering
problems will arise between the shaft 5 and the shaft member, as the socket body 170
is guided and centered by contact of the cavity sidewall 172 with the annular face
96 on the bearing-wall 8. Centering is further assured by corresponding tightening
of the screw bolts 178 and 179 which extend on both sides of the shaft piece 175 from
a shoulder 183 of the socket body 170 via bolt holes 184 and 185 in the latter toward
the rear and out of the rearward face 170a of the socket body 170 to enter corresponding
bores in the peripheral zone 180 of the frontal face 8b of the bearing-wall 8 (Fig.
1). Only the left-hand one, 181, of these bores is indicated in dashed outline in
Fig. 2. The ends of the screwbolts 178 and 179 protruding rearwardly from the bearing-wall
8 to the right and to the left of the impact unit 10 can be secured by nuts (not shown)
in a conventional manner.
[0174] The shaft piece 175 is supported rotatingly in the socket throughhole 173 by means
of a bronze bushing 182 and, with the flange 176 resting in the recess 174a, a locking
ring 187 and washer 188 fixed on the rearward shaft piece end secure the shaft piece
175 against axial displacement in the throughhole 173. In the case of the working
tool illustrated in Fig. 34 the forward end of the shaft piece which protrudes from
the collar 176 forward beyond the socket body 170, bears a square-head or the like
end 189 of poly gonal cross-sectional area. This head end can also have a transverse
bore 189a for purposes to be described further below.
[0175] A conventional drill chuck 190 having a socket 191 fitting, e.g. by a thread connection,
on to the head end 189 of the shaft piece 175 is shown in Fig. 34 holding clamped
in position and exchangeably a drill bit 192. The parts of the drill chuck are well
known and will not be described in detail.
[0176] A socket tool 203 serves for fastening or loosening bolts, by means of which, for
instance, automobile wheels are mounted on their hubs or removed. The socket tool
203 therefore comprises a forward part having a polygonal recess 207 of, for instance,
hexagonal cross-section when bolts having hexagonal heads are to be inserted therein,
while the rearward portion of the socket tool 203 has an axial polygonal recess 208
of, for instance square cross-section, when the intermediary shaft 5 of the power
tool apparatus according to the invention bears a square head end 95 (Figures 1 to
3).
[0177] The rotary tool unit illustrated in Fig. 37 is an angle sander or a cutting tool
and comprises a tool socket body which is almost identical with the connection socket
body 170 shown in Fig. 34. All identical parts of the two socket bodies 170 and 210
bear like reference numerals. The difference between the two socket bodies lies in
the external configuration of their central and forward portions.
[0178] The entire tool socket body 200 including its forward portion is of practically cylindrical
configuration, but has in its upper forward region a semi-annular recess 211 provided
to receive the rearward end of a closing shield 212 therein, while in its lower forward
region, a cut-away segment provides a vertical shoulder 213 and flat underside face
214 as well as a transverse groove 215 where the shoulder and underside face meet.
[0179] On the forward end 189ʹ of the shaft piece 175, which can be of circular in lieu
of polygonal cross section, there is mounted a bevel gear 216 whose stem part 217
is provided with a transverse bore 217a registering with the transverse bore 189a
of the forward shaft piece end 189ʹ and can be fixed thereon by means of a cotter
pin 218. It will be understood that by opening the shield 212, this bevel gear 216
is readily accessible and can be exchanged for another bevel gear of different toothing
or pitch to obtain a different transmission ratio and higher or lower speed of the
bevel gear 220. For instance, a speed of the intermediary shaft 5 and the shaft piece
175 of 2000 r.p.m. can be increased by a transmission ratio of 3:1 to a speed of 6000
r.p.m. and by a transmission ratio of 4:1 to a speed of 8000 r.p.m. of the vertical
shaft 222 and the tool 230 mounted thereon.
[0180] The bevel gear 220 is mounted on the upper end 221 of a vertical shaft 222 by means
of transverse bores 219 and 223 in the gear 220 and in the shaft upper end 221, respectively,
which bores register with each other and have a cotter pin 224 inserted therein. The
vertical shaft 222 bears an annular flange 225 integral therewith by means of which
it rests on ball bearings 227 and 228 in a tool-bearing body 229.
[0181] At its lower end 237 the shaft 222 has attached thereto in a conventional manner
a tool such as, in the instant case, a sander or rotary cutter 230.
[0182] At its upper end, the tool-bearing body 229 is provided with an extension constituting
a bracket arm 231 which is shaped to fit snugly into the angular space provided on
the connecting socket body 210 between the flat underside 214 and the vertical shoulder
213 and bears at the rearward end of its upper flat face a marginal, upwardly projecting
rim 231a which fits into the transverse groove 215. The bracket arm 231 is firmly
held in its position at the socket body 210 by means of a threaded bolt.
[0183] The rotary tool unit including the connecting socket body 210 is mounted firmly on
the bearing-wall 8 of the front end of the power tool according to the invention by
means of the threaded head bolts 178 and 179 (Fig. 35) whose hexagonal heads or nuts
are lodged in niches 212a of the closing shield 212 (only the left-hand niche - looking
at the shield from outside - is visible in Fig. 37) and are thus freely accessible.
The shield 212 can be snapped into place on the socket body 210 and the tool-bearing
body 229 and easily removed therefrom.
[0184] In the tool unit illustrated in Figures 38 to 40, the connecting socket body and
the angle cutter structure attached thereto are almost identical with those described
above relating to Fig. 37. Identical parts bear like reference numerals.
[0185] The means by which the tool unit of Figures 30-41 is attached to the bearing-wall
8 at the forward end of the power tool apparatus according to the invention are different
from those described hereinbefore and are illustrated in detail in Figures 38 and
39. In lieu of the threaded bolts 178 and 179 (Figures 34, 35 and 37), clamping means
are used which comprise a split, elastically outwardly biassed clamping ring 233 having
holes 234 in each eyelet 235 and a clamp bolt 236 inserted in the eyelet holes 234.
[0186] A hedge clipper 240 is attached to the lower end of the vertical shaft 222 of the
tool unit shown in Fig. 38. The clipper 240 comprises a stationary blade-bearing bar
241 and a movable blade-bearing bar 242. The stationary bar 241 is mounted on a reinforcing
rib 231a of the bracket arm 231 of the tool-bearing body 229 by means of an angle
piece 243 which is fastened to the bracket arm by a fastening screw connection 244
and is an integral upward extension of the stationary bar 241.
[0187] As can be seen in Figures 38 and 40, the lower end 237 of the vertical shaft 222
extends downwardly below the stationary bar 241, through a bore 238 thereof, and
bears an excenter disc 239 for rotation with the shaft 222. This excenter disc 239
is fitted into a slot 245a in an eyelet part 245 being at one end of the moveable
bar 242 on the underside 241a of the stationary bar 241. The latter bar bears rivet
studs 246 extending from its underside through elongated slots 247 in the moveable
bar 242 and holding the bar 242 in contact with the stationary bar 241 thereabove
by their lower enlarged rivet heads 248 while permitting a forward or backward axial
displacement of the moveable bar 242 in the slots 247 relative to the stationary
bar 241, thereby causing a shearing effect between the stationary bar blades 250 and
the moveable bar blades 251. The backward and forward displacement of the moveable
bar 242 is produced by the excenter disc 239 being rotated in the slot 245a by the
vertical shaft 222 and thereby pushing the bar 242 to the left in Fig. 40 upon the
shaft 222 rotating about 180°, and then pushing the bar 242 to the right, back to
the limit position shown in Fig. 40, during its rotation about the next following
180°.
[0188] Another cutting tool unit comprising a rotary blade can be obtained by the operator
using the kit according to the invention by detaching the tool socket 229 and the
bracket arm 231, the vertical shaft 222 and the bevel gear 220 from the unit by removing
the bolt 232, and then exchanging the large bevel gear for a large rotary blade on
a hub having the rearward stem part 216 and a transverse bore 217a therein which is
adapted to register with the transverse bore 189a in the shaft head end 189. The large
rotary blade can then be fastened on the shaft end 189 by means of a cotter pin 218.
[0189] A straight saw tool unit attachable to the power tool apparatus according to the
invention is illustrated in Figures 41 and 42. This saw tool unit comprises a tool
socket body 210 as described hereinbefore in relation to Fig. 37, all identical parts
bearing like reference numerals. However, the connecting shaft piece 175A therein
has a differently constructed portion forward of the central collar 176 thereof.
Instead of a polygonal forward head end 189 or 189ʹ it bears a crank pin 252 mounted
stationary and excentrically on the front face 186a of the shaft collar 176, or being
integral with the latter, and bearing articulatedly a crank 253 the upper end of
which engages the crank pin 252, while the lower crank end is connected articulatedly
by means of a crank joint 254 with the top end of a downwardly extending driving
rod 255 which is guided during reciprocating upward downward movement in an appropriate
bore in a guiding block 256. The guiding block 256 is mounted stationary on a base
plate 257 having a slot 258 therein, through which the straight saw blade 260 extends,
which is attached exchangeably at its upper end to the lower end of the driving rod
255 by conventional attachment means 259. A guide roller 261 mounted for rotation
in a forked holder 262 at the foot end of the guiding block 256 guides the saw blade
260 during its reciprocating movement.
[0190] In Fig. 43 there is illustrated a kit according to the invention comprising a minimum
of items. A power tool apparatus 300 according to the invention comprises the inset
building block illustrated in Figures 2, 2a and 2b, an angle sander 301 together with
a protecting shield 301a and a connecting piece 302, a portable battery 303 which
can be suspended from a belt worn by the operator, by means of a loop 303a, and a
connecting cord 304. The connecting cord is provided at one end with a smaller male
plug 304a for connection with the female plug 304b, on the battery 303, and at the
other end with a larger plug 100 destined to be inserted at the cap member 40 for
instance as illustrated in Fig. 9.
[0191] The battery 303 is preferably a nickel-cadmium battery delivering a direct current
of 12 volts. Such a battery weighs approximately 1300 g and will last long enough
to loosen 500 automobile wheel nuts each of a diameter of 10 mm, each with an energy
consumption of 64 Newton-meters.
1. An electric rotary power tool apparatus holdable by hand during operation and consisting
essentially of
(A) a first building block comprising
(1) an apparatus casing consisting essentially of an elongated assembly having
a longitudinal axis and comprising
(1.1) an enveloping shell extending generally in the direction of said longitudinal
axis, and having an open front end and an open rear end,and being of one piece;
(1.2) a first transverse wall extending across the interior of said shell in
a region thereof intermediate said front end and said rear end axially spaced from
both said ends so as to divide the shell interior into a forward chamber and a rearward
chamber; said first transverse wall having a throughhole therein and being integral
with said shell;
(1.3) a second transverse wall across said open rear end of said shell and being
detachably mounted therein; said second transverse wall having an opening therein,
and
(1.4) a speed-reducing unit mounted on said second transverse wall on the side
thereof facing toward said first transverse wall, and being adapted for fitting into
said rearward chamber in said enveloping shell; said speed-reducing unit comprising
a driven power-transmitting shaft having a driven shaft front end adapted for fitting
into said throughhole and protruding therefrom into said forward chamber;
(B) a second, rearward building block comprising
(2) a motor comprising
(2.1) a motor housing having a central longitudinal axis substantially parallel
with said elongated assembly axis, and comprising a surrounding hull, a forward hull
end, a rearward hull end wall, and being adapted for having said front end thereof
rigidly connected with said second transverse wall on the outside of the latter;
(2.2) driving motor shaft means extending through the interior of said motor
housing and being rotatably supported in said opening of said second transverse wall;
said driving rotor shaft means having a forward shaft end extending into said rearward
shell chamber and being adapted for drivingly engaging said speed-reducing unit therein;
(C) a third, inset building block adapted for being inserted in said forward
shell chamber through the open front end thereof, and comprising
(3) insertable bearing-wall means adapted for being mount-transversely in rigid,
detachable connection, in said open front end of said enveloping shell, and having
a central axial throughhole; said insert bearing-wall means comprising
(3.1) shaft-bearing means in said axial throughhole;
(3.2) intermediary power-transmitting insert means comprising
(3.2.a) insert shaft means having a forward and a rearward shaft end, said
rearward shaft end being adapted for driving engagement with said driven shaft front
end protruding into said forward shell chamber; said insert shaft means being supported
for rotation in said shaft-bearing means in a region of said insert shaft means near
said forward shaft end thereof; and
(3.2.b) a connecting piece on said forward shaft end and forward of said shaft
bearing means;
(3.3) centering socket means adapted for protruding forward out of said enveloping
shell and being located spaced outwardly from said throughhole; and
(3.4) tool fastener-engaging means adapted to be located outside said shell
and spaced outwardly of said axial throughhole;
the length of said enveloping shell forward chamber from said integral first
transverse wall to said open shell front end being sufficient for receiving all parts
of said third building block that are located rearward of said central axial throughhole
in said insertable bearing-wall means; and
the wall thickness and strength of said enveloping shell being sufficient for
supporting, when held freely by hand during operation, in combination with said first
building block, the entire second, rearward building block comprising said motor mounted
on said second transverse wall, as well as said entire third, inset building block
even when comprising heavy duty impact clutch means or the like, as part of said intermediary
power-transmitting insert means.
2. The apparatus of claim 1, wherein said speed-reducing unit comprises a gear train
consisting essentially of a plurality of gears and a number of transmission shafts
each bearing at least one gear, one of said gears being a pinion adapted for being
mounted on said forward shaft end of said driving rotor shaft means, and one of said
transmission shafts being comprised by said driven power-transmitting shaft means;
said transmission shafts being supported in said first and second transverse walls,
respectively.
3. The apparatus of claim 2, wherein said speed-reducing unit is adapted for reducing
the speed of said driving rotor shaft means to said driven power transmitting shaft
means in a ratio of from about 7:1 to about 12:1.
4. The apparatus of claim 1, wherein said motor comprised by said rearward building
block is an electric motor comprising
(2.3) a rotor mounted inside said motor housing on said driving rotor shaft
means for rotating the latter;
(2.4) stator means adapted for generating an electric field for cooperation
with said rotor; and
(2.5) commutator means comprising
(2.5.a.) a commutator consisting essentially of collector segments and being
mounted on said driving rotor shaft means between said rotor and said rearward motor
housing end wall;
(2.5.b.) first and second brush means mounted in said motor housing and biassed
toward said collector segments for electrically conductive contact therewith to deliver
electric current to said rotor;
(2.5.c.) first and second fixed contactor means being electrically conductively
connected with said first and second brush means, respectively, and being mounted
stationary in said rearward building block and having terminal portions located outside
said rearward motor housing end wall, said fixed contactor terminal portions bearing
contactable surface regions located generally in a substantially planar contact zone;
and
(2.5.d.) electrically conductive lead means adapted for connecting said first
and second brush means, respectively with said first and second fixed contactor means,
substantially free from electrical power losses.
5. The apparatus of claim 4, wherein said rearward building block further comprises
(4) an electrical switch means being adapted for switching a direct electrical
current comprising
(4.1) a supporting member having at least one electrically insulating face
located spaced from, and substantially parallel with, said substantially planar contact
zone, and also remote from said rearward motor housing wall and said contact zone;
said contactable surface regions of said terminal fixed contactor portions being
arranged about a common central switch axis extending normal with regard to said contact
zone;
said supporting member being mounted in said rearward building block to be adapted
for pivoting displacement about said central switch axis, between a neutral position
and at least one activating position;
(4.2) socket throughholes extending through said supporting member and opening
out of said electrically insulating face thereof, and being adapted for receiving
therein each a prong of an electrical plug having at least two prongs and being electrically
connectable to a source of electric current;
(4.3) at least two shiftable contactor elements being mounted on said electrically
insulating face of said supporting member so as to be electrically insulated from
each other, each of said contactor elements being located so close to a different
one of said throughholes in said supporting member face as to make substantially loss-free
contact with a prong of a plug inserted in the respective throughhole;
each of said shiftable contact members having a shiftable contact face extending
in an arc about and on opposite sides of said central switch axis;
(4.4) biassing means mounted in said rearward building block and being adapted
for biassing said shiftable contactor elements toward said fixed contactor means and
thereby urging said contact faces of said shiftable contactor elements into said substantially
planar contact zone;
said contact faces extending in said arcs being separated by gaps between them exposing
non-conductive areas which said biassing means urge against said contactable surface
regions of said terminal fixed contactor portions when said supporting member is
in neutral position, thereby preventing electric current flow from said shiftable
contact faces into said contactable surface regions; said non-conductive area gaps
being sufficiently small for permitting current flow, when said supporting member
is pivoted by a small angle about said central switch axis and away from said neutral
position, from a source of electric energy via said plug prongs and said shiftable
contact faces into said contactable surface regions, thereby energizing said electric
motor.
6. The apparatus of claim 5, wherein said rearward building block comprises
(5) a cap member adapted for covering said rearward motor housing end wall as
well as a substantial portion of said surrounding hull of said motor housing on the
outside, and having a cap end wall extending substantially parallel with said rearward
motor housing end wall and having an inner wall surface, an internal chamber being
left free between said inner wall surface and said rearward motor housing end wall;
said supporting member of said electrical switch means being located vis-à-vis
said inner face of said cap end wall and cap throughholes extending from outside said
cap end wall to said inner face thereof facing said supporting member; and
said biassing means comprise first and second engagement means, mounted on
the outside of said rearward motor housing end wall and on said insulating supporting
member face, respectively, and cooperating with each other in biassing said supporting
member toward said rearward motor housing end wall and, when said supporting member
is in neutral position, urging said non-conductive gap areas against said contactable
terminal portion surface regions, and, when said supporting member is in an activating
position, urging said contact faces of said shiftable contactor elements against said
contactable surface regions in said substantially planar contact zone.
7. The apparatus of claim 5, wherein said shiftable contactor elements are arc-shaped
and extend each over an arc constituting a major portion of a half circle about said
central switch axis, said arc-shaped contactor elements having at least one end thereof
beveled to form a ramp facilitating sliding of the contact face thereon on to the
respective contactable surface region of the nearest terminal fixed contactor portion,
when said supporting member is pivoted through a small angle from the neutral to an
activating position.
8. The apparatus of claim 5, wherein said electrical switch means comprise restoring
means for returning said supporting member automatically from an activating position
to its neutral position, said restoring means comprising a shaft member whose cross
sectional area of elongated configuration having a larger diameter in a first direction
and a smaller diameter in a second direction at right angle to said first direction,
and two elastically flexible blade members lying firmly and straight against opposite
flanks of said shaft member spaced from each other by said smaller diameter when said
supporting member is in neutral position, and lying with biassing torque against two
other opposite flanks of said shaft member, spaced by said larger diameter from each
other when said supporting member is in an activating position, said torque biassing
said shaft member to return to its neutral position, one of the two parts being constituted
by said supporting member insulating face and said rearward motor housing end wall
bearing said shaft member and the other part by said two blade members.
9. The apparatus of claim 6, wherein said supporting member has a circumferential
rim and is mounted in said cap member pivotably about said central switch axis; said
cap member being connected rigidly with said rearward motor housing wall; and said
supporting member comprises
(4.1.a) a switch-shifting member protruding tangentially from said supporting
member rim; and wherein
said cap member has a window registering with said switch-shifting member through
which window said switch-shifting member protrudes when said supporting member is
in neutral position; depression of the protruding end of said switch-shifting member
causing said supporting member to turn about said central switch axis and shift from
its neutral to an activating position.
10. The apparatus of claim 5, wherein said rearward building block comprises
(6) a handle part having at least two opposite handle sidewalls and being firmly
connectable with said first building block, said handle part having a central longitudinal
axis extending transverse relative to said longitudinal building block assembly axis;
said electrical switch means comprising
(4.5) stationary mounting means adapted for holding said first and second fixed
contactor means firmly in position therein relative to said central switch axis,
and being mounted in said handle part on an inside face of one of said opposite handle
sidewalls;
and said supporting member being mounted,pivotably relative to said central
switch axis, on an inside face of the other handle sidewall, in cooperative juxtaposition
to said fixed contactor means on said stationary mounting means.
11. The apparatus of claim 10, wherein said supporting member has a circumferential
rim and comprises
(4.1.a) at least one switch-shifting member protruding tangentially from said
supporting member rim,
said handle part having window means through which said switch-shifting member
is adapted to protrude when said supporting member is in neutral position; depression
of the protruding end of said switch-shifting member causing said supporting member
to turn by a small angle about said central switch axis and to shift from its neutral
to an activating position.
12. The apparatus of claim 6, wherein said electrical switch means comprise
(4.6) stationary mounting means adapted for holding said first and second fixed
contactor means firmly in position therein relative to said central switch axis, and
being mounted firmly on the outside of said rearward motor housing end wall;
said first and second engagement means of said biassing means are aligned with
each other along said central switch axis and are pivotably connected with said cap
member and said supporting member therein, and with said stationary mountingmeans,
respectively;
(4.7) restoring means being in engagement with said supporting member and comprising
arresting means adapted for being held in said stationary mounting means so as to
cause restoring bias applied to said supporting member when the latter is pivoted
from its rest position to an activating position; and wherein said rearward building
block further comprises
(6) a handle unit having at least two opposite handle sidewalls and being firmly
connectable with said first building block, said handle unit having a central longitudinal
axis extending between said handle sidewalls and transversely to said central longitudinal
motor housing axis;
said opposite handle sidewalls having upper end portions adapted for freely
supporting said cap member in a manner such that said cap member and said supporting
member therein can be pivoted between said neutral position and an activating position
of said supporting member;
said handle unit containing
(7) a second electrical switch having a second central switch axis and comprising
(7.1) a pair of third and fourth fixed contactor means,
(7.2) second stationary mounting means adapted for holding said third and fourth fixed
contactor means firmly in position therein relative to said second switch axis, and
being mounted in said handle unit on an inside face of one of said opposite handle
siidewalls;
said third and fourth fixed contactor means having terminal portions protruding
into an interspace between said opposite handle sidewalls from said second mounting
means, and bearing fixed third and fourth contactable surface regions, respectively,
located generally in a second planar contact zone;
(7.3) electrically conductive cord means extending through said handle unit,
having two ends one thereof being connect ed to said third and fourth contactor means;
said cord means comprising at the other end thereof plug means adapted for being
inserted through said cap member into contact with said contactable regions of said
first and second contactor means;
(7.4) secondary throughholes in said cap member for rendering said contactable
regions of said first and second contactor means accessible to contact by plug means
inserted in said secondary throughholes;
(7.5) a second supporting member having at least one electrically insulating
face located spaced from, and substantially parallel with said second planar contact
zone;
(7.6) handle socket throughholes opening out of said handle unit and being adapted
for receiving in each throughhole plug-connecting means associated with an electrical
plug being connectable to a source of electric direct current;
(7.7) at least two shiftable handle contactor elements being mounted on said
insulating face of said second supporting member so as to be electrically insulated
from each other, and close to said handle socket throughholes so as to make substantially
loss-free contact with said plug-connecting means when said electrical plug mentioned
under (7.6), supra, is connected to said handle socket throughholes;
(7.8) second biassing means mounted in said handle unit and comprising first
and second engagement means mutually pivotably engaged and cooperating with each
other in biassing said second supporting member toward said second stationary mounting
means, while being pivotable relative to each other, together with said second supporting
member and said second stationary mounting means;
said second supporting member having a peripheral rim and comprising
(7.5.a) at least one switch-shifting member tangentially protruding from said
rim of said second supporting member, said handle unit having window means through
which said switch-shifting member is adapted to protrude when said second supporting
member is in neutral position; depression of the protruding end of said switch-shifting
member causing said supporting member to turn about a small angle about said second
central switch axis and thereby to shift from its neutral to an activating position;
and
(7.9) second restoring means being in engagement with said second supporting
member and comprising second arresting means being held in said second stationary
mounting means so as to cause restoring bias to be applied to said second supporting
member when the same is pivoted from its neutral position to an activated position.
13. The apparatus of claim 6, wherein
said first and second engagement means of said biassing means are aligned with
each other along said central switch axis and are pivotally connected with said supporting
member inside said cap member and with said rearward motor housing end wall, respectively;
and
said rearward building block comprises
(6) a handle part having at least two opposite handle sidewalls and being firmly
connectable with said first building block, said handle part having a central longitudinal
axis extending between said sidewalls and transversely to said longitudinal building
block assembly axis;
said opposite handle sidewalls having upper end portions adapted for freely
supporting said cap member for rotating motion of the latter relative to said sidewalls
between said rest position and an activating position of said supporting member; and
said handle part comprising
(6.1) pivoting means for causing a pivoting motion of said cap member from said
rest position to an activating position of said suporting member therein,
said pivoting means being located in said handle and extending into engagement
with said cap member in an underside region of the latter intermediate said handle
sidewalls; and
(6.2) pivot-actuating means lodged in said handle part and adapted for being
depressed from outside said handle part, thereby causing said cap member to pivot
from said rest position to an activated position of said supporting member;
said electrical switch means further comprising
(4.7) restoring means for restoring said supporting member, and said cap member
together therewith, automatically from an activating position to said neutral position.
14. The apparatusof claim 13, wherein said restoring means are mounted in said handle
part and are in restoring engagement with said pivoting means therein.
15. The apparatus of claim 13, wherein said restoring means are in restoring engagement
with said supporting member and comprise arresting means;
and said electrical switch means further comprise
(4.6) stationary mounting means adapted for holding said first and second fixed
contactor means firmly in position therein relative to said central switch axis, and
being mounted on the outside of said rearward motor housing end wall;
said arresting means being held in said stationary mounting means so as to
cause restoring bias of said restoring means exerted on said supporting member when
the latter is pivoted from its neutral position to an activating position.
16. The apparatus of claim 4, wherein said rearward building block comprises
(5) a cap member adapted for covering said rearward motor housing end wall as
well as at least a substantial portion of said surrounding motor housing hull on the
outside thereof, said cap member having a cap end wall extending substantially parallel
with said rearward motor housing end wall;
said first and second fixed contactor means extending to said cap end wall,
(4.2) socket throughholes extending through said cap end wall to the outside
thereof and registering with said contactable surface regions of said fixed contactor
terminal portions and being adapted for receiving prongs of an electrical plug having
at least two such prongs and being connectable to a source of electric current; whereby
prongs inserted into said socket throughholes can be connected conductively with
said contactable surface regions;
one of said first and second fixed contactor means having a circuit-breaking
gap therein; and
said electrical switch comprises
(4.3) a circuit making element mounted in said cap member and being adapted
for radial inward displacement by outside pressure being applied thereto, so as to
bridge said gap in said one fixed contactor means and thereby make circuit; said
circuit-breaking element being biassed into undepressed, circuit-breaking position.
17. A working kit suitable for hobby work as well as constructional and the like
heavy duty work, comprising
(I) an electric rotary power tool apparatus holdable by hand during operation
and consisting essentially of
(A) a first building block comprising
(1) an apparatus casing consisting essentialy of an elongated assembly having
a longitudinal axis and comprising
(1.1) an enveloping shell extending generally in the direction of said longitudinal
assembly axis, and having an open front end and an open rear end;
(1.2) a first transverse wall being integral with said enveloping shell and
extending across the interior of said shell in a region thereof intermediate said
front end and said rear end and being axially spaced from both said shell ends so
as to divide the shell interior into a forward chamber and a rearward chamber; said
first transverse wall having a throughhole therein;
(1.3) a second transverse wall across said open rear end of said shell and being
detachably mounted therein; said second transverse wall having an opening therein;
and
(1.4) a speed-reducing unit mounted on said second transverse wall on the side
thereof facing toward said first transverse wall, and being adapted for fitting into
said rearward shell chamber; said speed-reducing unit comprising a driven power-transmitting
shaft having a front shaft end adapted for fitting through said first transverse wall
throughhole and protruding therefrom into said forward shell chamber;
said speed-reducing unit comprising a gear train consisting essentially of
a plurality of gears and a number of transmission shafts each bearing at least one
of said gears, one of said gears being a pinion, and one of said transmission shafts
being a driven power-transmitting shaft, said transmission shafts being rotatingly
supported in said first and second transverse walls, respectively; said gear train
being adapted to reducing the speed of said pinion to that of said driven shaft in
a ratio of from about 2:1 to about 12:1; and
(B) a second, rearward building block comprising
(2) a direct current electric motor comprising
(2.1) a motor housing comprising a surrounding hull, a forward hull end and
a rearward hull end wall, said motor housing being adapted for having said forward
hull end firmly connected with said second transverse wall on the outside thereof;
(2.2) driving rotor shaft means having a longitudinal axis being substantially
parallel with said longitudinal assembly axis and extending through the interior
of said motor housing, said driving rotor shaft means comprising a rotor shaft being
rotatably supported in said opening of said second transverse wall, and having a
forward shaft end extending into said rearward shell chamber and bearing said pinion
therein, for drivingly engaging said gear train;
(2.3) a rotor mounted inside said motor housing on said rotor shaft for rotating
the latter;
(2.4) permanent magnet stator means adapted for generating an electromagnetic
field in cooperation with said rotor adapted for excitation by a direct electric current
having a potential of about 8 to 30 volts and an amperage sufficient for affording
a power output of said motor, when idling, of at least 180 watt, and of at least about
620 watt under load;
(2.5) commutator means comprising
(2.5.a) a commutator consisting essentially of collector segments and being
mounted on said rotor shaft between said rotor and said rearward hull end wall;
(2.5.b) first and second brush means mounted in said motor housing and being
biassed toward said collector segments for electrically conductive contact therewith
and for delivering direct electric current to said rotor;
(2.5.c) first and second fixed contactors being electrically conductively connected
with said brush means and being mounted stationary in said rearward hull end wall
and having terminal contactor portions bearing contactable terminal regions thereon
located in an interspace,beyond said rearward motor hull end wall, in said rearward
building block, said contactable regions being located generally in a common planar
interspace contact zone;
(2.5.d) electrically conductive lead means adapted for connecting said first
brush means with said first fixed contactor, and said second brush means with said
second fixed contactor, and being adapted for carrying direct electrical current
of the voltage and amperage defined, supra, substantially free from electrical power
losses;
(4) first electrical switch means being adapted for switching a direct electrical
current having the voltage and amperage defined, supra, and comprising
(4.1) a first supporting member having at least one electrically insulating
face spaced from and substantially parallel with said planar interspace contact zone,
said contactable terminal regions being arranged about a first central switch
axis being normal to said electrically insulating face of said first supporting member;
said supporting member being adapted for pivoting displacement about said central
switch axis, between a neutral position thereof and at least one activating position;
(4.2) socket throughholes through said supporting member and being adapted for
receiving therein the prongs of an electrical plug being electrically connectable
to a source of direct electric current;
(4.3) at least two shiftable contactor elements being mounted on said electrically
insulating face of said first supporting member so as to be insulated from each other,
each of said contactor elements being associated with a different one of said socket
throughholes to make substantially loss-free contact with a prong of a plug inserted
in the respective throughhole; and each of said shiftable contact members having a
contact face of curved configuration about and on opposite sides of said first central
switch axis;
(4.4) first biassing means associated with said rearward hull end wall and comprising
first and second engagement means,
(4.6) first fixed mounting means adapted for holding said first and second fixed
contactors firmly in position therein relative to said first central switch axis,
and being mounted fixedly on the outside of said rearward motor hull end wall;
said first engagement means being mounted on said first fixed mounting means,
and said second engagement means being mounted on said first supporting member, said
first and second engagement means being engaged with one another in a manner such
that said supporting member is biassed toward said first planar contact face and said
first mounting means;
(4.7) restoring means for restoring said first supporting member automatically
from an activating position to said neutral position;
said rearward building block further comprising
(5) a cap member adapted for covering at least a substantial portion of said
surrounding hull of said motor housing and having a cap end wall extending substantially
parallel with and spaced from the outside of said rearward housing end wall, an internal
chamber being left free between said rearward hull end wall and the inner face of
said cap end wall, through which internal chamber said first planar contact plane
extends;
said first supporting means being located inside said cap member vis-à-vis said cap
end wall;
those socket throughholes being associated with said two shiftable contactor
elements extending from outside said cap member and through the latter and also through
said first supporting member, and two other, additional throughholes extending from
outside said cap end wall and through said first supporting member thereon, and opening
out of said electrically insulating face thereof to register with said contactable
terminal regions of said first and second fixed contactors, respectively, when said
supporting member is in neutral position;
said first and second engagement means of said first biassing means being pivotably
engaged with each other, whereby said first supporting member in said cap member can
be pivoted about said first central switch axis relative to said first mounting means
by at least a small angle; and, when said first supporting member is in activated
position, said biassing means urge said shiftable contactor elements against said
contactable terminal regions of said first and second fixed contactors;
(II) at least one of the following kit items:
(a) an electrical cable having two ends and comprising at one end thereof connecting
means for attachment to a source of direct electrical current, and at the other end
an electrical plug comprising prong-receiving holes therein being electrically trically
conductively connected, through said cable, with said connecting means, and prongs
adapted for being mounted fixedly in at least one of (i) said socket throughholes
of said first supporting member, and (ii) said prong-receiving holes of said plug;
(b) a handle part having at least two opposite handle sidewalls and being firmly
and detachably connectable with said first building block, said handle part having
a central longitudinal axis extending between said handle sidewalls and transversely
to said central longitudinal motor housing axis;
said opposite handle sidewalls adapted for freely supporting said cap member
and said first supporting member therein to be pivotable about said first central
switch axis between said neutral position and an activating position;
said handle part comprising
(7) second electrical switch means adapted for switching a direct electrical
current having the voltage and amperage defined, supra, and comprising, about a second
central switch axis,
(7.1) a pair of third and fourth fixed contactors;
(7.2) second fixed mounting means adapted for being mounted on an inside face
of one of said opposite handle sidewalls in said handle part and for holding said
third and fourth fixed contactors firmly in position relative to said second central
switch axis;
said third and fourths contactors protruding into an interspace between said
opposite handle sidewalls and bearing third and fourth contactable regions, respectively,
being located in a second planar contact zone;
(7.3) electrically conductive cord means extending through said handle part
and having two ends, said third and fourth fixed contactor means being conductively
connected with one end of said cord means; said ends of said cord means comprising
(6.1) a handle cord plug conductively connected with said other end of said
cord means, and
(6.2) lead prongs on said cord plug adapted to be inserted, respectively, into
said additional socket throughholes in said cap end wall and to make contact, through
said first supporting member, with said contactable terminal regions of said first
and second fixed contactors, respectively, while arresting said first supporting member
in neutral position;
said second electrical switch means further comprising
(7.5) a second supporting member having at least one electrically insulating
face extending thereon spaced from, and substantially parallel with, said second planar
contact zone;
(7.6) handle socket throughholes opening out of said handle part and being adapted
for receiving therein prongs of an electrical plug of said electrical cable;
(7.7) at least two shiftable handle contactor elements mounted on said insulating
face of said second supporting member, to be electrically insulated from each other,
each of said handle contactor elements being associated with a different one
of said handle socket throughholes to make substantially loss-free contact with connecting
plug means of said electrical cable when said plug is inserted into said handle socket
throughholes;
(7.8) second biassing means mounted in said handle part and comprising first
and second engagement means adapted for cooperating with each other in biassing said
second supporting member toward said second fixed mounting means, and being connected,
for pivotal movement relative to each other, with said second supporting member and
said second fixed mounting means, respectively;
said second supporting member comprising actuating means extending to the outside
and having a depressable portion protruding to outside said handle when said second
supporting member is in neutral position; depression of said depressable portion of
said actuating means causing said supporting member to pivot about said second central
switch axis from its neutral position to an activating position; and
(7.9) second restoring means being in engagement with said second supporting
member and said second fixed mounting means, respectively, and being adapted to cause
restoring bias applied to said second supporting member when the same is pivoted from
its neutral position to an activated position;
(c) a portable battery adapted for being carried on an operator's person, in
combination with battery cable means adapted for being connected to said portable
battery, on the one hand, and being adapted to be connected, on the other hand, with
one of
(iii) said two shiftable contactor elements of said first supporting member;
and
(iv) said shiftable handle contactor elements of said second supporting member;
(III) at least one of the following inset units comprising each the following
parts:
(3) insertable bearing-wall means adapted for being mounted transversely, detachably
and in firm position in said open front end of said enveloping shell of said first
building block, said insert bearing-wall means having a central axial throughhole
and comprising
(3.1) shaft-bearing means in said axial throughhole;
(3.2) an insertable power-transmitting intermediary unit comprising
(3.2.a) insertable shaft means having a forward shaft end and a rearward insertable
shaft end, said insertable shaft means being supportable for rotation in said shaft-bearing
means engaging a region of said insertable shaft means near said forward shaft end,
said rearward shaft end of said insertable shaft means being adapted, upon insertion
into said forward chamber of said enveloping shell, for drivingly engaging said driven
shaft front end protruding from said first transverse wall into said forward shell
chamber;
(3.2.b) a square-head type connecting piece on said forward end of said insertable
shaft means, and being located forward of said shaft-bearing means;
(3.3) centering socket means adapted for protruding forwardly out of said enveloping
shell and being located spaced outwardly from said throughhole; and
(3.4) tool-fastening means adapted for being located outside said enveloping
shell and being spaced outwardly from said axial throughhole;
said insert units being constituted by:
(8A) an insert unit consisting of the parts defined under (3) through (3.4),
supra, per se;
(8B) an insert unit comprising, besides the parts defined under (3) through
(3.4), supra,
(8.1) fan means mounted on said insertable shaft means in a region thereof,
being located in the interior of said forward shell chamber, upon insertion of said
unit therein; and
(8.2) vent means provided in said transverse walls of said forward and rearward
chambers of said enveloping shell, as well as in said insertable bearing-wall means;
(8C) an insert unit comprising, besides the parts defined under (3) through
(3.4), supra,
(8.3) an impact-generating unit mounted on said insertable bearing-wall means
and on said insertable shaft means;
(8D) an insert unit comprising, besides the parts defined under (3) through
(3.4), supra, a hammer drill mounted on said insertable shaft means;
all of said insert units fitting with the parts thereof rearward of said bearing-wall
means, into said forward chamber of said enveloping shell;
and said working kit further comprising:
(IV) at least one of the following tools each of which comprises
(9) coupling means adapted for firm, detachable and centered coupling of the
respective tool with said centering socket means; and
(10) tool operating shaft means comprising a coupling shaft end adapted for
being drivingly connected with said square head-type connecting piece at the forward
end of said insertable shaft means;
and is constituted by
(IV.1) nut-loosening and tightening socket means;
(IV.2) screw driver means;
(IV.3) a drilling tool;
(IV.4) a blade saw tool;
(IV.5) an angle tool comprising at least one of sander and cutter means.
18. Electrical direct current switch means comprising
(1) first and second fixed contactor means adapted for being at one end thereof,
electrically conductively connected to electrical lead means constituting a first
part of a path of electric current flow, said first and second contactor means having,
at their other end, each a terminal portion bearing a contactable surface region;
(2) stationary mounting means adapted for holding said first and second fixed
contactor means firmly in position in a mounting face thereof relative to a central
switch axis normal to said mounting face,
(3) a pivotable supporting member having at least one electrically insulating
face, each such insulating face being spaced from a different contactable surface
region of said first and second fixed contactor means;
(4) socket throughholes extending through said supporting member and opening
out of an electrically insulating face thereof, and being adapted for receiving each
a prong of an electric plug located in said path of electric current flow;
(5) at least two shiftable contactor elements being mounted on said electrically
insulating face so as to be insulatedly spaced from each other and adapted for making
contact with a prong of said plug having been inserted in a corresponding one of said
throughholes;
(6) biassing means comprising first and second engagement means; said first
engagement means being mounted on said stationary mounting means, and said second
engagement means being mounted on said supporting member being engaged with one another
in a manner such that said supporting member is pivotable through at least a small
angle relative to said stationary mounting means between a neutral and at least one
circuit-making position, and, when said supporting member is in an activated position,
said biassing means urge said shiftable contactor means against said contactable
surface regions of said fixed contactor terminal portions; and
(7) a cap member comprising a cap end wall and a hull part upstanding axially
therefrom about an inner face of said cap end wall; said inner face of said cap end
wall being turned toward a face of said pivotable supporting member facing away from
said electrically insulating face thereof.
19. The electrical switch means of claim 18, wherein said shiftable contactor elements
are arc-shaped and extend each over an arc constituting a major portion of a half
circle about said central switch axis, said arc-shaped contactor elements having
at least one end thereof beveled to form a ramp facilitating sliding of the contact
face thereon on to the respective contactable surface region of the nearest terminal
fixed contactor portion, when said supporting member is pivoted through a small angle
from the neutral to an activating position.
20. The electrical switch means of claim 18, wherein said contactable surface regions
of said stationary contactor means are located in the sidewalls of said terminal
portions thereof; and
said pair of shiftable contactor means are pin-shaped, each having a lateral
contact region and being mounted in said supporting member and extending substantially
axially relative to said central switch axis from outside said outer face thereof
and through said cap member and protruding from the inner face of said supporting
member toward said stationary mounting means and into said substantially planar contact
zone by a distance such as to extend parallel with said stationary contactor terminal
portions by a sufficient length for said lateral contact regions of said shiftable
contactor means to make contact with said contactable sidewall regions of said terminal
portions in axially extending contact zones thereof, when said supporting member is
angularly pivoted into either one of two limit positions relative to said stationary
mounting means, while breaking contact when in at least one intermediate positions
between said limit positions;
said cap member having passage means for the introduction of a pair of lead
means extending from a source of electric energy, into the interspace between said
stationary mounting means and said inner face of said cap member end wall, and into
electrically conductive engagement with said pair of shiftable contactor means.
21. The electrical switch means of claim 20, wherein said shiftable contactor means
are so disposed in said cap member as to be switched by corresponding turning of said
cap member to adopt at least three different positions, in a first "off" one of which,
parts of said shiftable contactor means at the inner face of said cap member are
out of contact with both said first and second stationary contactor means, while in
a second position, a first one of said shiftable contactor means makes contact with
said first stationary contactor means lodged in said stationary mounting means, and
the second shiftable contactor means makes contact with said second stationary contactor
means projecting from said stationary mounting means, thereby being capable of activating
a motor for rotating a driving shaft thereof in a given direction of rotation, and,
in a third position, the second one of said shiftable contactor means makes contact
with said first stationary contactor means, and the first shiftable contactor means
makes contact with said second stationary contactor means, thereby being capable of
reversing the direction of rotation of said motor and said driving shaft.
22. The electrical switch means of claim 20, wherein, of two regions consisting of
said lateral contact region and said contactable sidewall region a first one comprises
inwardly crimped contact spring parts and the other region is pin-shaped so as to
be clampingly engagable by the first region.