[0001] This invention pertains to the control of gripper arms in insertion machines.
[0002] More particularly the invention concerns an insertion machine comprising a plurality
of insert stations whereat supplies of insert material are at least temporarily stored;
an insert track which is indexed along said plurality of insert stations for the transport
of inserts deposited thereon; gripper arm means associated with a plurality of insert
stations, said gripper arm means each comprising a first jaw member; a second jaw
member, said second jaw member being selectively movable with respect to said first
jaw member for the engagement of insert material therebetween; means for selectively
actuating said first and second jaw members to a first position whereby insert material
is engageable between said jaw members and to a second position at which insert material
is released from between said jaw members and deposited on said insert track, and
means for controlling said plurality of actuating means whereby the actuation of each
of said gripper arms for the release of insert material is controllable.
[0003] Such a machine is described in U.S. Patent Specification US-A-2,325,455 (A.H.Williams).
The gripper arms of such machines typically each have fixed and movable jaw members.
The fixed jaw member is usually integral with the gripper arm while the movable jaw
is selectively operated so that articles, such as documents or inserts, can be engaged
between and released from the two jaws.
[0004] Prior art gripper arms have traditionally been mounted on two elongated shafts which
extend above and along an insert transport track or raceway. The first or upper shaft,
which oscillates once per machine cycle, has an upper portion of the gripper arm keyed
thereto so that the gripper arm oscillates toward and away from a corresponding insertion
supply station in timed relationship with the other operations occuring at the station.
The second shaft also oscillates once during each machine cycle to actuate the movable
jaw member into and out of engagement with the fixed jaw member in timed relationship
with the oscillation of the gripper arm about the first shaft and with the rest of
the machine. A cam keyed to the second shaft acts upon a connecting rod which in turn
moves the movable jaw member away from the fixed jaw member against the action of
a tension spring. The jaws are held apart in this manner until the gripper arm is
oscillated toward the corresponding insertion station whereat the movable jaw is positioned
above and the fixed jaw is positioned below an insert. The second shaft then oscillates
to close the movable jaw against the fixed jaw to engage and grip the insert. The
first shaft thereupon swings away from the insert station, pulling the selected insert
therefrom in a direction toward the insert track. Over the insert track the second
shaft is oscillated to move the movable jaw member away from the fixed jaw and thereby
release the insert, permitting the insert to fall onto the transport track.
[0005] Although only one gripper arm structure has been described above, it should be understood
that a plurality of gripper arms are provided with an insertion machine, each gripper
arm being positioned in relation to corresponding insert stations linearly arranged
along an insert track. Insertion machines of this type described above can operate
through a range of speeds. An operator may at a lower end of the operational speed
range "step" or "jog" the machine through a machine cycle at a very slow speed as
is useful in the case of setting up the machine with new material. At high operational
speeds the insertion machine may operate at a rate in the neighborhood of 10,000 cycles
per hour.
[0006] In setting up an insertion machine, the operator must be cognizant of the fact that
each insert must be released at a precise location along the insert track, usually
within 3.175 mm (l/8 inch)of a specified precise location. In this respect, each insert
must be released so that the insert contacts both of a pair of pusher pins that index
the insert down the insert track. The time delay associated with the actuation of
the movable jaw member thus becomes a factor in determining where on the insert track
the insert will be released.
[0007] If the delay time in actuating the movable jaw member is constant regardless of the
operational speed of the machine, significant error can occur in placement of the
insert on the insert track. For example, a delay of 20 to 25 milliseconds in actuating
the movable jaw member when the insertion machine is operating at 10,000 cycles per
hour results in the gripper arm travelling approximately one inch. Thus a give magnitude
of time delay in actuating the movable jaw member in the jog mode or at low speed
is not suitable for higher operational speeds and can, when the machine is operated
at higher speeds, result in significant misplacement of the insert on the insert track.
European Patent Specification EP-A-0174214 (published 12th March l986) addresses the
foregoing problem by providing a solenoid actuated gripper arm wherein the magnitude
of delay involved in actuating a movable jaw member is related to the operational
speed of the insertion machine in conjunction with which the gripper arm is employed.
[0008] The operational speed of an insertion machine is but one factor which is pertinent
to the timing of the actuation of gripper arm jaw members and hence the proper placement
of inserts on an insert track. Another factor affecting the timing of the release
of inserts at proper positions on the insert track is the size of the inserts. In
this regard, it is desirous that each gripper arm release its inserts so that each
insert will be contacted by both advancing pusher pins on the insert track. When the
size of inserts vary from insert station to insert station, and when all the gripper
arms associated with the insert stations along an insert track are actuated to release
their inserts at the same point in a machine cycle, an insert of an odd size may be
released and deposited on the insert track in a manner whereby it cannot contact both
of its pusher pins. The prior art manner of essentially simultaneously releasing inserts
from the various stations regardless of insert size can ultimately result in skewed
insert placement, which in turn can cause jamming on the insert track.
[0009] The insert tracks or raceways of many conventional insertion machines have side rails
or the like which extend on opposite sides of the insert track and substantially along
the length (i.e. the major dimension or direction of travel) of the insert track.
In many insertion machines the positioning of one or both of these side rails is adjustable
so that the distance separating the side rails can be selectively varied. In some
insertion machines, for example, the side rail nearest from the row of insert stations
can be moved through a displacement range of as much as four inches while the side
rail furtherest the row of insert stations can be moved through a displacement range
of as much as 19.05 mm (3/4 inch). The selective adjustment of the side rails advantageously
permits the insertion machine to accommodate on its insert track inserts of varying
size. For example, if the size of the inserts vary from insert station to insert station,
the side rails can be positionally adjusted sufficiently far apart so that the largest
of the inserts at the various insert stations can be accommodated on the insert track.
[0010] In order to accommodate the very large size inserts that might be present at one
of the insert stations, an operator typically first moves the side rail furtherest
from the row of insert stations to its maximum displacement. If the insert track is
still not wide enough the operator can then move the side rail nearest the row of
insert stations closer to the insert stations to further broaden the insert track.
While the selective positional adjustment of the side rails advantageously permits
the insertion machine to accommodate on its insert track inserts of varying and especially
large size, in a sense this adjustment capability is also a mixed blessing in that
it further complicates the precise positioning of inserts on the insert track.
[0011] The present invention is characterized in that the control means includes a plurality
of station presettable timing means whereby for each of said gripper arms there is
provided an independent time component which is related to a characteristic of insert
material at its associated insert station as indicated by a corresponding predetermined
input value.
SUMMARY OF THE PREFERRED EMBODIMENT OF THE INVENTION
[0012] An insertion machine has a plurality of gripper arms, each gripper arm including
jaw members between which inserts are engaged and from which engaged inserts are released
in precise placement upon a transport means. Each jaw is actuated by actuating means
acting through linkage means to perform the engagement and release operations. Upon
insert engagement the activation of the actuating means is controlled to be dependent
upon the operating speed of the insertion machine. Upon insert release the activation
of each actuating means is controlled so that release is delayed by three release
time delay components. A first release time delay component is occasioned by a master
presettable release delay means which delays the release operation actuating means
of all insert stations in accordance with a preset input value. A second release time
delay component is dependent upon the operating speed of the insertion machine. A
third release time delay component, which varies from insert station to insert station
depending on insert size, is occasioned by individual station presettable release
delay means which delays the release operation of actuating means for its insert station.
[0013] The first release time delay component is useful whenever an insert station has such
large inserts that a side rail nearest the row of insert stations is moved closer
to the insert stations to widen an insert track upon which inserts are to be deposited.
This first or master release delay component is implemented simultaneously for all
gripper jaws at all insert stations by selecting an appropriate value corresponding
to the delay component on a master release delay thumbwheel switch. The master release
delay thumbwheel switch presets a presettable down counter. During insert engagement
operation a master preset release delay circuit comprising the presettable down counter
and its associated thumbwheel switch has no appreciable impact, i.e. occasions no
delay component, but upon initiation of the insert release operation the master preset
release delay circuit overrides further operation until the expiration of a period
corresponding to its selected release delay component. The release delay component
implemented by the master preset release delay circuit essentially corresponds to
the period required by the presettable down counter to count down a number of encoder
pulses equal to the value to which the counter was selectively preset by the master
release delay thumbwheel switch.
[0014] The second release time delay component is implemented after the master preset release
delay circuit has had an opportunity to implement its release delay component. The
second release time delay component is essentially a function of the operating speed
of the insertion machine. To implement this machine speed dependent release delay
component a counter B counts trailing edges of encoder pulses and a counter A counts
clock pulses which occur after trailing edges of encoder pulses. When it is determined
that at the occurrence of a leading edge of an encoder pulse that the contents of
counters A and B are equal, a flip-flop changes state in order to signal the end of
the machine speed dependent release delay component. Similar operation occurs for
implementing a machine speed dependent engagement delay component. The machine speed
dependent delay components are uniformly applied to gripper jaw actuating means (solenoids)
at all insert stations.
[0015] The third release time delay component is implemented upon the expiration of the
machine speed dependent release delay component. The third or station preset release
delay component is implemented individually with respect to each insert station in
accordance with a selected value on each station's own station release delay thumbwheel
switch. The station thumbwheel switch and a presettable shift register comprise for
each station a station preset release delay circuit. The value selected on the station
thumbwheel switch presets the shift register in accordance with the desired duration
of the third release delay component. Implementation of this third release delay component
involves the shifting of the contents of the preset pulses until shifting is completed.
When a false signal appears at the output pin of the shift register, a driver transistor
ceases electrical conduction to deactivate the actuating solenoid. Deactivation of
the solenoid causes gripper jaw members to open whereby an insert is deposited on
the insert track.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing and other objects, features, and advantages of the invention will be
apparent from the following more particular description of the preferred embodiments
as illustrated in the accompanying drawings in which reference characters refer to
the same parts throughout the various views. The drawings are not necessarily to scale,
emphasis instead being placed upon illustrating the principles of the invention.
[0017] FIG. 1 is a diagrammatical view of portions of an insertion machine according to
an embodiment of the invention;
[0018] FIG. 1A is a rear view of a gripper arm according to an embodiment of the invention;
[0019] FIG. 1B is a side view taken along the line "C" of the gripper arm of Fig. 1A;
[0020] FIG. 2 is an exploded view of the gripper arm of another embodiment of the invention;
[0021] FIG. 3 is a diagram showing the relationship of Figs. 3A and 3B;
[0022] FIG. 3A and FIG. 3B are schematic diagrams depicting electrical circuitry included
in actuator control means according to an embodiment of the invention;
[0023] FIG. 4 is a diagram showing the relationship of Figs. 4A and 4B;
[0024] FIGS. 4A and 4B are timing diagrams depicting the electrical states of various electrical
components included in the actuation control means of Figs. 3A and 3B for an insertion
machine operating at about 4,000 cycles per hour;
[0025] FIGS. 5A and 5B are timing diagrams depicting the electrical states of various electrical
components in the actuator control means of Figs. 3A and 3B for machines operating
at about 4,000 cycles per hour and at about 8,000 cycles per hour, respectively;
[0026] FIG. 6 is a detailed view of a portion of the gripper arm of Fig. 1A;
[0027] FIG. 7A is a detailed rear view of a portion of the gripper arm of Fig. 1A;
[0028] FIG. 7B is a detailed view of a portion of the gripper arm of Fig. 12A cut along
the line "D";
[0029] FIG. 8 is a side sectional view showing first sensor means and second sensor means
mounted in relationship to main drive shaft means; and,
[0030] FIG. 9 is an end view of an actuator timing disc included in a second sensor means.
DETAILED DESCRIPTION OF THE DRAWINGS
[0031] Referring to Fig. 1, there is shown an insertion machine 10 which collects a plurality
of inserts into a pile and transports that pile to an inserting station IS; conveys
an open envelope to inserting station IS; and, then inserts the pile of inserts into
the envelope. During steps unillustrated in Fig. 1 the insertion machine 10 later
seals the envelope and processes the envelope for mailing. It will be appreciated
that the operation of machine 10 is timed in accordance with a machine cycle. In this
respect, an individual envelope requires several machine cycles to be processed. With
the exception of a few initial or start-up machine cycles, a pile of inserts is inserted
into an awaiting corresponding envelope at the end of each machine cycle.
[0032] In order for insertion machine 10 to collect a pile of inserts at inserting station
IS, there are provided therein a plurality of insert stack stations or hoppers S1,
S2, and S3 and a plurality of corresponding gripper arms 16₁, 16₂, and 16₃ each mounted
to a shaft 17 which extends over an insert raceway 18. Insert station S1, gripper
arm 16₁, and shaft 17 serve to withdraw one insert from the stack of inserts and drop
that insert onto raceway 18. More particularly, insert station S1 holds a stack of
inserts I₁ in a manner whereby the bottommost insert is separable from the rest of
the stack. Gripper arm 16₁ is connected to shaft 17 which oscillates once during a
portion of each machine cycle in order to rotate arm 16₁ toward and away from the
stack of inserts. While rotating toward the stack, the jaws of gripper arm 16₁ are
opened to allow the arm to engage the bottommost insert. When the shaft 17 stops moving
arm 16₁ toward the stack, the jaws are closed to engage the bottommost insert. Shaft
17 then rotates gripper arm 16₁ away from the stack, thereby withdrawing the insert
from the bottom of the stack. Gripper arm 16₁ then opens its jaws to release the insert
which falls onto insert raceway 18. Thus, insert station S1, gripper arm 16₁, and
shaft 17 cooperate to withdraw one insert from the stack and drop that insert onto
raceway 18.
[0033] Insert raceway 18 includes a plurality of pairs of pusher pins P which are mounted
on a pair of chains (not shown) which are periodically driven by machine 10. The chains
are driven once during a portion of each machine cycle and move the pusher pins P
to the next insert station. After the just-described dropping of an insert from station
S1 onto raceway 18, for example, pins P push the insert to the vicinity of the insert
station S2 and stop.
[0034] Insert raceway 18 is bordered by a first side rail SR1 which is furtherest from the
row of insert stations S1, S2, S3, and a second side rail SR2 which is nearest the
row of insert stations. The side rails SR1 and SR2 are selectively movable in the
direction of arrow SRA to selectively widen or narrow the insert raceway 18.
[0035] In view of the foregoing, it will be seen that insert station S1, gripper arm 16₁,
shaft 17, and raceway 18 cooperate to withdraw one insert from the stack and convey
that insert to station S2. It will be appreciated that for the embodiment shown one
insert from station S1 is conveyed to station S2 each machine cycle.
[0036] Insert station S2, gripper arm 16₂, and shaft 17 cooperate in a similar manner as
insert station S1, gripper arm 16₁, and shaft 17 and serve to withdraw one insert
from the stack of inserts at station S2 and drop that insert onto raceway 18. More
particularly, insert stack station S2 holds a stack of inserts I₂ in a manner whereby
the bottommost insert is separable from the rest of the stack. Gripper arm 16₂, which
is also connected to oscillating shaft 17, rotates toward the bottommost insert; grabs
that insert; rotates away from the stack; and, then releases the insert. This insert
falls onto insert raceway 18 which already contains an insert I₁. Pusher pins P of
raceway 18 advance this pile to the next insert station. Thus, during another machine
cycle, insert station S2, gripper arm 16₂, shaft 17, and raceway 18 cooperate to add
an insert I₂ to insert I₁ and convey the pile to station S3.
[0037] Insert station S3, gripper arm 16₃, and shaft 17 cooperate in a similar manner as
insert stations S1 and S2, gripper arms 16₁ and 16₂, and shaft 17 and serve to withdraw
one insert from the stack of inserts at station S3 and drop that insert onto raceway
18. Insert stack station S3 separates the bottommost insert from the rest of a stack
of inserts I3. Gripper arm 163 rotates toward the bottommost insert; grabs that insert;
rotates away from the stack; and, releases the insert onto inserts I₁ and I₂ on raceway
18. This thereby completes the pile of inserts. Raceway 18 then conveys the completed
pile to inserting station IS. Thus, during a third machine cycle, insert station S3,
gripper arms 16₃, shaft 17, and raceway 18 cooperate to add an insert I₃ to a pile
of inserts and convey the pile to inserting station IS.
[0038] In view of the foregoing, it will be seen that insert stack stations S1, S2, and
S3, respective gripper arms 16₁, 16₂, and 16₃, and insert raceway 18 cooperate to
collect a pile of inserts and convey that pile to inserting station IS in three machine
cycles.
[0039] As mentioned above, insertion machine 10 conveys an open envelope to inserting station
IS. To this end there are provided an envelope stack station ES; an envelope flap
opening station EO; a flap hold down bar 19; and, an envelope raceway 21. Envelope
stack station ES holds a stack of envelopes; separates the bottommost envelope from
the rest of the stack; and, feeds the envelope to a clamp C in envelope raceway 21.
Envelope raceway 21 includes clamp C which is mounted on a chain (not shown) which
is periodically driven by machine 10. The chain is driven once during a portion of
each machine cycle and moves the envelope to an envelope flap opening station EO.
At station EO, a sucker cup (not shown) rotates toward the closed flap of an envelope,
applies a vacuum to the flap and rotates away from the envelope in order to open the
flap of the envelope. The raceway 21 then moves the envelope to the inserting station
IS while the flap of the envelope is held down by bar 19.
[0040] When an envelope and a pile of inserts are at inserting station IS, insertion machine
10 inserts the pile of inserts into the opened envelope. To this end, there are provided
in machine 10, a pusher arm PA, and a vacuum bar VB. The vacuum bar VB lifts up the
back (top) side of the envelope and shaft 17 rotates and thereby moves pusher arm
PA toward the opened envelope. As a result, the pile of inserts will be pushed into
the envelope. Thus, pusher arm PA and vacuum bar VB cooperate to insert a pile of
inserts into an opened envelope at inserting station IS.
[0041] Although Fig. 1 shows an insertion machine with three insert stack stations S1, S2,
and S3, it should be understood that the number of insert stack stations is not critical
to the present invention and that in other embodiments fewer or more such insert stations
are employed along a suitable raceway.
[0042] During the operation of machine 10 it is highly desirable to provide an indication
when one of the gripper arms grips too few or too many inserts. Insertion machine
10 includes an improved double/miss detector which is relatively easy to calibrate
and adjust and which is described in EP-A-0174214 referred to above.
[0043] In addition, it should be appreciated that it is desirable to provide a reliable
gripper arm. Insertion machine 10 includes a reliable gripper arm which will now be
described.
GRIPPER ARM MECHANICAL STRUCTURE
[0044] Each gripper arm 16 according to an embodiment of the invention includes a housing
20; securing means 22 for securing the gripper arm to oscillating drive means such
as shaft 17; a first article-contacting or jaw member 24; a second article-contacting
or jaw member 26; jaw actuation means, such as solenoid actuation means 28; and, linkage
means 30. Figs. 1A and 1B (as well as Figs. 6, 7A, and 7B) show a gripper arm according
to one embodiment of the invention while Fig. 2 shows a gripper arm of a second embodiment
which is generally similar to the embodiment of Figs. 1 but which includes different
structure for its linkage means. Structural elements common to the embodiments of
Figs. 1A and 1B and Fig. 2 are assigned the same reference numerals for description
purposes hereinafter.
[0045] Gripper arm housing 20 has a distal end 32 and a proximal end 34. The means 22 for
securing the gripper arm to the oscillating drive shaft 17 includes (1) a semi-cylindrical
recess 36 at the top of the proximal end 34 of the gripper arm housing 20, and (2)
a clamp member 38. The recess surface 36 is contiguous with flanges 40 on either side
of the recess 36. The flanges are generally parallel to the major cylindrical axis
of the recess 36. The clamp member 38 mates with the proximal end 34 of the housing
20. The clamp 38 is formed with comparable flanges 42 which mate with the flanges
40 of housing 20. The clamp 38 has a cylindrical sector portion 44 which forms a semi-cylindrical
recess 46. Each of the flanges 40 and 42 have two threaded apertures therein appropriately
aligned to receive threaded fasteners 48. In this respect, flanges 40 have apertures
50 and flanges 42 have apertures 52. The fasteners 48 secure clamp 38 to the proximal
end 34 of the housing 20 so that the gripper arm is clamped onto the oscillating drive
shaft 17. Each threaded fastener 48 extends through the aligned apertures 50,52 and
the housing flanges 40 and the clamp flanges 42, respectively.
[0046] The gripper arm housing 20 comprises opposing side panels 54 which extend the height
of the gripper arm. The two side panels 54 define a space therebetween. At the proximal
end 34 of the gripper arm housing 20 the side panels 54 are parallel and separated
by a distance A as shown in Fig. 1A. At the mid-section of the gripper arm housing
the side panels 54 begin to converge to one another but separate before doing so and
continue in parallel manner to the distal end 34 of the housing 20. At the distal
end of the housing the side panels 54 are spaced apart at a distance B which is less
than distance A as shown in Fig. 1A.
[0047] In the region where the side panels 54 are separated by the distance A, a front panel
56 is integral with the side panels 54. In this region where the side panels 54 are
separated by the distance A, each side panel 54 has at its back a perpendicularly
extending flange 58. Each flange 58 has two threaded apertures 60 therethrough, as
well as a vertically extending channel 62 at the intersection of the plane which includes
the interior surface of the housing-side panel 54 and the plane which includes the
flange 58.
[0048] The gripper arm housing 20 also includes a backplate 64 which has a back member 66
and a base member 68 perpendicular thereto. The back member 66 has four apertures
70. Two of the apertures 70 are on each side of the back member 66, each aperture
70 being aligned with apertures 60 on the side panel flanges 58 when the back member
is assembled to housing 20. Threaded fasteners 72 extend through the apertures 70
of backplate 64 and through the aperture 60 of the side panel flanges 58 to secure
the backplate 64 to the gripper arm housing 20. The base member 68 of the backplate
64 is adapted for placement between the side panels 54 in an area where the side panels
begin to converge.
[0049] As described above, the side panels 54, front plate 56, back member surface 56, and
backplate base member 58 generally define a hollow volume 74. Volume 74 is not totally
confined, however, inasmuch as the base member 68 of the backplate 64 has an aperture
76 therein and the height of the back member 66 of backplate 64 is such as to leave
an essentially rectangular gap 78 above the backplate 64.
[0050] Volume 54 houses the jaw actuating means which, in the illustrated embodiment, is
solenoid means 28. The solenoid means 28 has an essentially cylindrical casing 80.
Solenoid casing 80 has a mounting plate 82 secured thereto. In the embodiment shown,
the mounting plate 82 has protrusions 84 thereon adapted to fit into the channel 62
of the side panel flanges 58. As shown in Fig. 2, electrical leads 86 extend from
the interior of the solenoid casing 80 and are included in a ribbon-type cable 90.
Although not shown as such in Fig. 1A, it should be understood that the ribbon cable
90 extends from the volume 74 out through the rectangular gap 78 on the back of the
gripper arm and is connected to appropriate circuitry including the type of circuit
shown in Figs. 3A and 3B. The circuitry to which the ribbon cable 90 is connected
resides on a circuit board or the like situated elsewhere on the particular machine
in conjunction with which the gripper arm of the invention operates.
[0051] The solenoid means 28 also comprises a plunger means 92. Near its base plunger means
92 has an annular groove about which C-clamp retainer 96 fits. The lower end of the
plunger 92 has a slot 98 therein through the diameter of the plunger 92. The plunger
92 also has an aperture 100 extending therethrough along a diameter of the plunger
92 which is transverse to the slot 98. The plunger aperture 100 is adapted to receive
a rollpin 102.
[0052] Turning now to the embodiment of Fig. 2, the linkage means 30' comprises a biasing
means and a connecting rod 120. The biasing means includes a cylindrically coiled
inner spring or extension spring 122 having coils formed generally in planes perpendicular
to the major axis of the cylinder. The inner spring 122 has first and second ends
formed in ring-like fashion, the end rings being formed in planes in which the axis
of the cylinder lies (that is, the planes of the end rings are generally perpendicular
to the planes of the coils included in inner spring 122). Ring 124 at the upper end
of the inner spring 122 is adapted to receive pin 102 therethrough when the ring 124
is inserted into the slot 98 of the plunger 92. Ring 126 at the lower end of the inner
spring 122 is adapted to receive a pin 128. Lower ring 126 receives pin 128 when the
lower ring 126 is inserted into a transverse slot 130 formed in a first end of end
cap 132. End cap 132 has an aperture 134 through the diameter thereof which intersects
the slot 130 in perpendicular fashion in a manner similar to the slot 98 in apertures
100 of the plunger 92.
[0053] End cap 132 has an annular shoulder 136 near its midsection so that an outer spring
138 can be confined between the shoulder 136 and the base member 68 of the backplate
64. Thus, the outer spring 138 is of greater diameter than the inner spring 122 fits
in concentric fashion over the inner spring 122. The outer spring 138, according to
one mode of the invention, preloads the inner expansion spring 122 by stretching spring
122 a desired distance so that spring 122 causes jaw 26 to exert a force of a desired
magnitude on inserts engaged between jaws 24 and 26.
[0054] As further seen in Fig. 2, the lower end of the end cap 132 receives a threaded top
140 of the connecting rod 120. The connecting rod 120 extends between planes in which
the side panels 54 are included downwardly toward the distal end 32 of the housing
20. The rod crooks outwardly to the side at point 142 as it extends downwardly, and
then bends inwardly to have a portion 144 in horizontal orientation at the lowest
extent of its travel. The lower end 144 of the rod is adapted to receive a lock member,
such as C-clamp retainer 146.
[0055] The distal end 32 of the gripper arm housing 30 has, in the Fig. 2 embodiment shown,
a first jaw member 24 which is formed integral with the housing 20 as a lower jaw
member. A rectangular recess 160 is formed in a surface of the jaw 24 which is oriented
to contact an article to be engaged by the gripper arm. The recess 160 is adapted
to receive a piece of high coefficient of friction material, such as a piece of urethane
162.
[0056] The second jaw member 26 as shown in Fig. 2 comprises a block 170 insertable in a
space defined by the separated lower ends of the side panels 54. The block 170 has
a protruding curved member 172 extending therefrom, the underneath surface of which
contacts articles to be engaged by the gripper arm. Block 170 also has two apertures
174 and 176 extending therethrough. The aperture 174 is adapted to receive a pivot
pin 178 so that the second jaw member 26 can pivot about the pin 178. The second aperture
176 is adapted to receive the horizontally extending lower end portion 144 of the
connecting rod 122.
[0057] The pivot pin 178 is received not only through aperture 174 in the jaw member 26,
but also through aligned apertures 180 in the distal end of the side panels 54. Thus,
when the second jaw member 26 is inserted in the space between the side panels 54
near the distal end 32 of the gripper arm housing 20, the apertures 174 and 180 are
aligned so that the pivot pin 178 can freely fit therethrough. The pivot pin 178 is
retained in position by a set screw 181 so that the pivot pin 178 rotates in bearing-like
end caps 182.
[0058] The embodiment of Figs. 1A and 1B differs slightly from the embodiment of Fig. 2,
in the configuration of the particular linkage means utilized. While the embodiment
of Figs. 1A and 1B, like that of Fig. 2, has an inner spring 122, the inner spring
122 of the embodiment of Figs. 1A and 1B is positioned in a cylindrical spacer or
housing 202. As in the Fig. 2 embodiment, the upper ring 124 of the inner spring 122
is secured by plunger pin 102 to the solenoid plunger 92. The top of the cylindrical
housing 202 abuts the lower end of the plunger 92.
[0059] The lower end of cylindrical housing 202 abuts a retaining ring 203. The retaining
ring 203 is carried in an annular recess on a clevis-type end cap 204. The pin 128
extends radially through the end cap 204 in a manner understood from the description
of the end cap 132 of Fig. 2. End cap 204 axially receives a pin 205 which has an
upper exterior portion thereof threaded for engagement in an axial aperture of end
cap 204. An upper end of a cable 206 is connected to the lower end of pin 205. Cable
206 extends from the pin 205 to the distal end 32 of the gripper jaw. At its lower
end the cable 206 has a ball 208 fixedly attached thereto.
[0060] Located in the cylindrical housing 202 in the manner described above, the inner spring
122 of Figs. 1A and 1B is held so that it is generally extended about 0.25 inches
beyond its length at rest. The spring 122 is thus preloaded to have a desired spring
force.
[0061] For the embodiment of Figs. 1A and 1B, the upper jaw member 26 comprises a block
member 210 and a curved protrusion 212. The underside of the protrusion is used to
contact articles engaged by the gripper arm. The block member 210 has a narrow slit
214 at the back thereof through which the lower portion of cable 206 extends. At the
base of the slit 214 is an essentially square chamber 215. Chamber 215 houses ball
208. When cable 206 is pulled upwardly, the ball 208 thereon, having a greater diameter
than the width of the slit 214, bears against the top interior surface of the chamber
215, causing the upper jaw member 26 to pivot so that the upper jaw member 26 approaches
the lower jaw member 24 so that the jaw essentially closes.
[0062] The block member 210 of second jaw 26 also has three apertures 216, 218, and 220
extending therethrough. The central aperture (aperture 218) accommodates a pivot pin
222 about which the jaw member 26 pivots.
[0063] The embodiment of Figs. 1A and 1B further comprises means for biasing the jaw members
in an open position. The biasing means includes torsion spring 230 (seen in Figs.
7A and 7B). An intermediate portion of the torsion spring 230 has a helical shape
which is concentric with and fits over an exposed end of pivot pin 222, the end of
pin 222 protruding beyond a side panel (the left side panel as seen in Fig. 7B) of
the gripper arm. At its exposed, protruding end the pivot pin 222 has a head 232 formed
thereon. A disc 234 is secured on the pivot pin 222 just inside its head 232. The
helical portion of the torsion spring extends between the disc 234 and the left side
panel of the gripper arm. At one of its ends the torsion spring 230 departs from its
helical configuration and assumes a linear shape as it extends upwardly to a retaining
pin 236 against a side of which it bears (see Fig. 7B). At its other end the torsion
spring 230 extends through a square notch 238 formed on the circumference of the disc
234. The portion of the torsion spring 230 that extends through the disc 234 bears
against a corner 240 of the notch 238. Spring 230 bears against corner 240 to exert
a biasing force on the disc 234 and the pivot pin 222 whereby the upper jaw member
26 is normally held open in the absence of application of tension to the cable 206.
When cable 206 and ball 208 thereon are urged upwardly, however, ball 208 bears against
the upper interior surface of the chamber 215 and exerts a force on block 210 which
overcomes the biasing force of the torsion spring 230 so that block 210 pivots about
pin 222, thus causing jaw 26 to close.
[0064] Reference numerals on the order of 400 seen in Figs. 7A and 7B concern mistake detection
apparatus. The details of such mistake detection apparatus in conjunction with which
the gripper arm of the present invention operate are described in European Patent
Specification EP-A-0174214 referred to above.
GRIPPER ARM ACTUATION CONTROL MEANS STRUCTURE
[0065] Figs. 3A and 3B show the circuitry of control means for actuating a plurality of
gripper jaws according to an embodiment of the invention. As shown in Figs. 8 and
9, an encoder disc 260 and an actuator timing disc 262 are mounted to rotate on a
main drive shaft 263 of a machine, such as an insertion machine, in connection with
which the gripper arm 16 of the invention operates. The main drive shaft rotates once
per machine cycle and has various timing and drive means rigidly coupled thereto for
power transmission, such as the aforementioned oscillating drive means 17, for example.
The encoder disc 260 is a 64-tooth disc. The actuator timing disc 262 has its circumference
configured to allow the passage of light (in a direction perpendicular to the plane
of the disc) about a disc central angle 266 corresponding to portions of a machine
cycle during which the actuation means of the gripper arm is to be actuated so that
the second jaw is either in contacting relation with the first jaw or has an article
gripped between the first jaw and the second jaw.
[0066] Fig. 3A shows an encoder disc sensor 300 including the above-mentioned encoder disc
260 positioned to cause passage of light from an LED 302 to be periodically incident
on circumferential teeth of the encoder disc. If the light from LED 302 impinges on
a tooth of the disc, then the light is not transmitted to receiver 304. If a circumferential
space between the teeth on the encoder disc is aligned with a beam of light from LED
302, then the receiver 304 detects the light. An actuator timing disc sensor 306 also
includes the above-mentioned actuator timing disc 262 with an LED 308 and a photoreceiver
310 similarly arranged about the actuator timing disc.
[0067] The opto-interrupt receiver 304 is connected to an inverting driver 312. The output
terminal of driver 312 is connected through a 10K resistor to the two tied-together
input terminals of an encoder NAND gate 314. The output terminal of encoder NAND 314
is connected to line 315. Likewise, the opto-interrupt receiver 310 is connected to
the input terminal of an inverting driver 316. The output terminal of the inverting
driver 316 is similarly connected through a 10K resistor to the two tied-together
input terminals of an actuator timing NAND gate 318. The output terminal of actuator
timing NAND 318 is connected to line 319.
[0068] The means for controlling the actuation of a plurality of gripper jaws as shown in
Figs. 3A and 3B further includes oscillator or clock means (shown framed by the broken
line 320); master presettable release delay means (shown framed by the broken line
322); multivibrator means such as "D"-type flip-flop 323; counter means (shown framed
by the broken line 324); count comparison means (such as the 4-bit magnitude comparator
326); EOR gates 328 and 330; multivibrator means such as "D"-type flip-flop 332; an
encoder pulse bus 334; an actuator timing bus 336; and, a plurality of station presettable
release delay means (such as the three such delay means respectively framed by the
broken lines 338A, 338B, and 338C). In this respect, the station presettable release
delay means 338A is associated with the first insert station S1; the release delay
means 338B is associated with the second insert station S2; and, the release delay
means 338C is associated with the third insert station S3. Except for the fact that
the delay means 338B and 338C electrically connect to their corresponding solenoid
actuators and gripper arms 16₂ and 16₃, respectively, the circuit details of delay
means 338B and 338C are similar to the structure disclosed for station presettable
release delay means 338A and therefore are not fully shown.
[0069] The clock means 320 comprises a gatable oscillator multivibrator 340 which has pins
5, 7, 12, 8, and 9 grounded and pins 4 and 16 connected to +15 volts. Pins 1 and 3
of the multivibrator 340 are connected together through a .0047 farad capacitor while
pins 3 and 2 are connected through the series combination of a 100K resistor and a
50K trimpot. In the configuration shown, the multivibrator 340 is adapted to produce
pulses at its Q output terminal (pin 10) having a period of 3.2 milliseconds when
a false signal is applied on lines 315 and 341 to pin 4 (the A input).
[0070] The master presettable release delay means comprises a presettable down counter 342;
a master presettable release delay thumbwheel switch 344; and, an EOR gate 346. The
down counter 342 is of the type wherein the presence of a true signal (on lines 319
and 343) at the preset enable terminal (pin 1) allows the counter to store therein
the binary value seen at the preset data input terminals (pins 4, 12, 13, and 3).
These preset data input pins are each connected through a 4.7K resistor to the output
terminals of the master delay thumbwheel switch 344. Thumbwheel switch 344 has a dial
thereon which, when positioned in the 1 position causes a binary 1 to be stored in
presettable counter 342; when positioned in the 2 position causes a binary 2 to be
stored in the counter 342; and so forth for the 4 and 8 positions. The clock input
pin (pin 15) of the down counter 342 is connected by lines 315 and 341 to the output
terminal of the encoder NAND 314. Pins 5, 9, 10, and 8 of counter 342 are grounded;
pin 16 is connected to +15 volts. The carryout pin (CO) of down counter 342 is adapted
to produce a false signal when it is counted down from its preset value to zero.
[0071] The EOR 346 has its first input terminal connected to the CO terminal of down counter
342 and its other input terminal connected to a true level voltage. The output terminal
of the EOR 346 is connected to the clock input terminal (pin 11) of the flip-flop
323.
[0072] The set terminal of flip-flop 323 is connected by line 319 to the output terminal
of the actuator timing NAND 318. The D (data) and R (reset) pins of the flip-flop
323 are grounded. The Q output pin of the flip-flop 323 is connected by a line 350
to input terminals of the EOR gates 328 and 330.
[0073] The counter means 324 includes a dual synchronous decade counter shown framed by
the broken line 352 and a NAND gate 354. Counter 352 includes two counters -- Counter
A (also known as counter 352A) and Counter B (also known as counter 352B).
[0074] The clock input pin (pin 1) of counter 352A is connected by line 356 to the Q output
terminal of the multivibrator 340 whereby counter 352A receives clock pulses when
the signals on lines 315 and 341 are false (i.e. the encoder pulses are false). Output
pins Q1, Q2, and Q3 of counter 352A are connected to input pins A₀, A₁, and A₂ included
in a first input bank of the comparator 326. Output pin Q3 is also connected to the
two input terminals of NAND gate 354. The output terminal of NAND 354 is connected
to the clock enable pin (pin 2) of counter 352A. The reset terminal of counter 352A
is connected through line 358 (having diode 360 thereon) and line 315 to the output
terminal of the encoder NAND 314 whereby counter 352A is reset upon the reception
of leading edges of each encoder pulse.
[0075] The clock enable pin (pin 10) of counter 352B is connected through lines 341 and
315 to the output terminal of the encoder NAND 314. The clock input pin (pin 9) of
counter 352 is grounded. Output pins Q₁, Q₂ and Q₃ are connected to corresponding
input pins B₀, B₁, and B₂ in a second bank of the comparator 326. The reset pin (pin
15) of counter 352B (as well as the input pin B₃ of comparator 326) is connected by
line 362 to the output terminal of the EOR 328.
[0076] Output pin 5 of the comparator 326 is connected by line 364 to an input terminal
(pin 1) of the EOR 330. In being connected to pin 5, line 364 carries a true signal
only when the binary value presented at the first or "A" input bank of comparator
326 is greater than the binary value presented at the second or "B" input bank. Input
pin 2 of the EOR 330 is connected by line 350 to the Q output pin of the flip-flop
323.
[0077] The "D" terminal (pin 5) of the flip-flop 332 is connected to the output terminal
of the EOR 330. The clock input terminal (pin 3) of flip-flop 332 is connected by
the line 315 to the output terminal of the encoding NAND 314. The Q output terminal
(pin 1) of flip-flop 332 is connected through an inverting driver 366 to an LED 368.
The Q output pin (pin 2) of the flip-flop 332 is connected both to an input terminal
(pin 12) of the EOR 328 and to the input terminal of an inverting driver 370. The
output terminal of the inverting driver 370 is in turn connected by line 372 to the
actuator timing bus 336. The set and reset terminals of the flip-flop 332 are grounded.
[0078] The encoder pulse bus 334 shown in Fig. 3B is connected by line 374 and line 315
to the output terminal of the encoding NAND 314.
[0079] The station presettable release delay means 338A shown in Fig. 3B comprises inverting
drivers 379, 380, 381, 382, 383, and 384; NAND gate 385; presettable shift register
means (such as 64-bit presettable shift register 386); station thumbwheel switch 387;
and, an NPN driver transistor 388.
[0080] The input terminal of the driver 379 is connected to the actuator timing bus 336.
The output terminal of the driver 379 is connected to an input terminal of the driver
380, whose output terminal is connected both to the preset enable pin (the "A" pin
or pin 7) of the shift register 386 and to an input terminal of the driver 381. The
output terminal of the driver 381 is connected to the input terminal of the driver
383. The output terminal of the driver 383 is connected to a point 389 on a voltage
division network. In the voltage division network, a 2K resistor is connected between
point 389 and +24 volts; a 10K resistor is connected between point 389 and a point
390; and, a 3.3K resistor is connected between point 390 and ground. Point 390 of
the voltage division network is connected to the base of the driver transistor 388.
Driver transistor 388 is connected in a circuit by leads 86 to the gripper jaw actuating
means such as solenoid 28.
[0081] An input terminal of the inverting driver 384 is connected to the encoder pulse bus
334. The output terminal of the driver 384 is connected through a 10K resistor to
both input terminals of the NAND 385. The NAND 385 has its output terminal connected
to the clock input terminal (pin 4) of the shift register 386. The output terminal
Q (pin 10) of the shift register 386 is connected to the input terminal of the driver
382. The output terminal of the driver 382 is connected to the input terminal of the
driver 383, whose output terminal is connected to the voltage division network in
the manner before described.
[0082] Station delay thumbwheel switch 387 has four output terminals connected to four corresponding
input terminals of the shift register 386. Thumbwheel switch 387 has a dial thereon
which, when positioned to point to a 1 position, applies a binary 1 to the input terminals
of shift register 386. By moving the indicator dial to the 2 position a binary 2 is
applied to the input terminals of the shift register 386, and so forth with respect
to the 4 and 8 positions. When a true signal is applied at the preset enable pin (pin
7) of shift register 386 the value applied at the input terminals of shift register
386 as indicated by the dial position on thumbwheel switch 387 determines the length
of the shift register 386. When the true signal is removed from the preset enable
pin (pin 7) of shift register 386, the shift register 386 is shifted in response to
the receipt of clock pulses at pin 4. When the preset data has completely shifted
through the shift register 386, the output terminal Q goes from a true value to a
false value.
[0083] As mentioned before, the structure of the station presettable release delay means
338B and 338C for stations S2 and S3, respectively, are essentially identical to that
described with respect to station S1 (i.e. station presettable release delay means
338). However, it should be understood that the thumbwheel 387 for each station is
independently set in consideration of the physical characteristics (such as size)
of the particular insert material to be engaged at that station and then released
by the appropriate gripper arm 16 onto the insert track 18. For example, the thumbwheel
switch 387A is set at a position of binary 2; the thumbwheel switch 387B is set at
a position corresponding to binary 8; and, the thumbwheel switch 387 for station S3
is set at a position corresponding to a binary 1. In this example, station S2 contains
extremely large inserts; station S1 contains fairly large inserts but not as large
as those in station S1; and, station S3 contains inserts which are about average size
or perhaps just slightly larger than average.
OPERATION
[0084] The operation of the actuator control means and associated gripper arm are hereinafter
described. The first general phase of operation described hereinafter is the closing
of the plurality of gripper jaws to engage inserts between the gripper jaws so as
to pull the inserts from its stack at the insert stations. A second general phase
of operation described hereinafter is the opening of the plurality of gripper jaws
such as takes place when inserts are released for dropping onto the raceway 18.
[0085] For the most part the ensuing discussion of the operation of the control of the gripper
arms assumes that the normal operations of the insertion machine are currently on-going
although at a rather slow rate of about 4,000 machine cycles per hour, particularly
discussion had with reference to the timing diagrams of Figs. 4A and 4B. It should
be understood that the operation at the selected speed of 4,000 machine cycles per
hour is, except for matters of timing, quite similar to that which occurs at a faster
speed. In this respect, at an appropriate point in the discussion Figs. 5A and 5B
will be discussed to contrast the timing effects of the slower mode of operation (about
4,000 cycles per hour in Fig. 5A) and a faster mode (about 8,000 machine cycles in
Fig. 5B).
[0086] The ensuing discussion further assumes that insert station S1 has inserts I₁ therein
of a rather large size; that insert station S2 has inserts therein of an even larger
size; and, that insert station S3 has insert therein which are of about average size.
The inserts I₂ in insert station S2 are presumed to be so large in fact that the operator
has had to move side rail SR1 further away from the row of insert stations, to accommodate
the large insert. In view of the presence of such large inserts at station S2 and
the required adjustment of side rail SR1, the operator first presets the master delay
thumbwheel switch 344 to a greater value to reflect that the rail SR1 has been moved
further from the insert stations as shown in Fig. 1A. For our example the thumbwheel
switch dial is set to a binary 2 which, as hereinafter seen, means that a release
delay in two encoder pulses will occur for each of the insert stations included in
the insertion machine. Thus the operator is able to simultaneously institute a uniform
release delay for all insert stations to take into consideration the adjusted width
of the insert track 18. It will be appreciated that simultaneous adjustment using
means 322 provides considerable convenience when adjustments must be made for an insertion
machine having a large plurality of stations.
[0087] The operator then makes individual adjustments if necessary for each of the insert
stations S1 S2, and S3. In this respect, since very large inserts are stored in insert
station S2, the operator sets the thumbwheel 387D to its greatest setting (8) so that
the gripper jaw 16₂ will have an even further release delay of eight encoder pulses.
Since rather large inserts also at station S1 and a further release delay is necessary
for properly positioning the inserts on the insert track, the operator sets the dial
switch for thumbwheel 387A to the 2 position (meaning that the gripper jaw 16₁ is
to release its insert after a further delay of two encoder pulses). Since the inserts
I₃ in insert station S3 are of average size, the operator merely sets the dial of
thumbwheel switch 387C to the 1 position for only a one encoder pulse release delay.
Thus the operator is able to provide a release delay for each station based on each
station's insert size and which is not necessarily uniform from station to station.
Moreover, if at any time during operation the positioning of an insert on the insert
track 18 seems slightly off, the operator can use the appropriate thumbwheel switch
387 to fine tune the insert placement.
[0088] The operation of the timing control means of the embodiment of Figs. 3A and 3B for
an insertion machine having a plurality of insert stations and operating at a rather
slow mode of about 4,000 machine cycles per hour is understood with reference to Figs.
4A and 4B. In this respect, Figs. 4A and 4B are timing diagrams showing the electrical
states of various components included in the circuitry of Figs. 3A and 3B. In particular,
Figs. 4A and 4B show: (1) a machine operating speed dependent engagement delay component
(from time T = 2 to T = 18); (2) a master preset release delay component occasioned
by the setting of thumbwheel switch 344 (from time T = 59 to T = 69); (3) a machine
operating speed dependent release delay component (from time T = 69 to T = 84); and,
(4) a station preset release delay component occasioned by the setting of switch 387
at insert station S1 (from time T = 84 to T = 96).
[0089] During the operation of the insertion machine light from the LED 302 of the opto-interrupter
of encoder disc sensor 300 radiates through spaces between the teeth on the encoder
disc so as to be incident upon receiver 304, causing the receiver 304 to output a
true signal to the inverting driver 312. Inverting driver 312 inverts the true signal
to a false signal for application to the encoder NAND 314. A false signal applied
to both input terminals of the encoder NAND 314 causes a true signal to be placed
on lines 315 and 341.
[0090] When the teeth of the encoder disc interrupt the light from between the LED 302 and
the receiver 304, a false signal appears at the output of the encoding NAND 314 and
hence on lines 315 and 341. Thus, as the encoder disc rotates, a series of pulses
is produced. In the series of encoder pulses generated by the 64-tooth disc, the machine
main shaft rotates 5.625 degrees of the machine cycle (5.625 DMC) between the leading
edges of consecutive true signals. The grafts of encoder pulse trains generated in
this manner appear in Figs. 4A and 4B.
[0091] Whenever the encoder pulse signals on lines 315 and 341 are false, the clock 320
is activated to produce clock pulses on line 356 having a period of 3.2 milliseconds.
Whenever the encoder pulse goes true, clock 320 ceases its output of clock pulses.
As shown in Figs. 4A and 4B, at a machine operating speed of approximately 4,000 cycles
per second the clock 320 produces approximately three clock pulses while the encoder
pulses are false. In this respect, the greater the operating speed of the machine
the fewer the number of clock pulses occur per encoder pulse.
OPERATION CONTROLLING ENGAGEMENT ACTUATION OF GRIPPER JAWS
[0092] When the actuating timing disc 262 is in a position to permit light to pass from
LED 308 to receiver 310 actuator timing NAND 318 has a true output which is applied
to lines 319 and 343. The particular actuator timing disc discussed with reference
to Fig. 4A permits light to pass from LED 308 to photoreceiver 310 during the time
T = 2 to T = 59. It is during this approximate time frame (T = 2 to T = 59 when light
is passing from the LED 308 to the photoreceiver 310) that the insertion machine expects
the solenoids 28 associated with the various insert stations to be actuated to an
engaged position so that inserts may be engaged therebetween and extracted from the
insert stations. However, a delay dependent upon the operating speed of the machine
occurs between the time T = 2 and the actual engagement actuation of the solenoid
28. In this respect, as hereinafter shown, when the machine is operating at approximately
4,000 machine cycles per hour the speed dependent engagement delay occurs from time
T = 2 to T = 19, a delay of approximately three encoding pulses.
[0093] The speed dependent engagement delay occurs while counter 352B counts up a number
of encoder pulses equal to the number of clock pulses being clocked into counter 352A
during the false portion of each encoder pulse. If the pulse count in the counters
352A and 352B are equal when the leading edge of an encoding pulse is applied to the
clock 10 of flip-flop 332, the actuator bus 336 goes true to ultimately actuate each
of the solenoids 28 at the insert stations so that inserts are engaged to each of
the insert stations.
[0094] In the above regard, a true signal on line 319 ultimately removes the true signal
that otherwise is present at the reset pin of counter 352B, thereby enabling counter
352B to count up the trailing edges of encoder pulses appearing on line 341. In this
respect, the true signal on line 319 sets flip-flop 323 so that a true signal appears
at the Q output on line 350. The true signal on line 350 coupled with a true signal
from the Q output of flip-flop 332 causes the EOR 328 output to go false, thereby
removing the reset to counter 352B.
[0095] It is noted that the master resettable release delay means 322 has no impact upon
engagement actuation. In this respect, while the actuator timing disc permits light
to pass to indicate the desired timing of engagement, the true signal on lines 319
and 343 are applied to the preset enable pin of down counter 342. As long as the true
signal appears at the preset enable pin of counter 342, counter 342 does not count
down but is being preset with the binary value indicated on the master delay thumbwheel
switch 344. As long as the down counter 342 is being preset, the carryout terminal
of counter 342 is true, causing the output of EOR 346 to go false. With the false
output from EOR 346 flip-flop 323 does not clock out pulses.
[0096] The trailing edge of the next occurring encoder pulse after the output of actuator
timing NAND 318 goes true accomplishes two basic objectives. First, the trailing edge
of this next occurring encoder pulse increments counter 352B so that (as shown at
time T = 4) counter 352B has a "1" value therein. Second, the trailing edge of this
next occurring encoding pulse also activates clock 320 so that a series of clock pulses
is applied to the clock input pin of counter 352A as long as the signals on lines
315 and 341 are false.
[0097] The clock pulses produced by clock 320 are counted by counter 352A. As shown in Fig.
4A, the three clock pulses generated during the time period T = 3 to T = 6 are counted
by counter 352A so that, at the leading edge of the next encoder pulse, counter 352A
ultimately contains a "3" value. When counter 352A reached 2, however, the comparator
326 determines that the value in counter 352A exceeded the value in counter 352B and
thus applied a high signal on line 364. The true signal on line 364 caused the output
of EOR 330 to go false. When clocked in by the leading edge of the encoding pulse
occurring at time T = 6, the false output signal from EOR 330 failed to change the
output of flip-flop 332 so that the state of the actuator bus 336 also remains unchanged
(meaning that the solenoids 28 are not yet actuated, i.e. that the gripper jaws are
not yet in their engaged position).
[0098] At the trailing edge of the next encoder pulse (time T = 9) the counter 352B is incremented
to contain the value "2". Counter 352A again counts up clock pulses from clock 320.
At the time of the leading edge of the next encoding pulse (time T = 12) a true signal
is occurring on line 364 since comparator 326 determined that the value in counter
352A exceeds the value in counter 352B. The output of EOR 330 is false, meaning that
the states of flip-flop 332 and the solenoids remain unchanged.
[0099] The trailing edge of the next encoder pulse (at time T = 15) causes the counter 352B
to be incremented to the value "3". Counter 352A counts up three clock pulses in the
manner described before. Thus, at the leading edge of the next encoder pulse (time
T = 18) the comparator 326 determines that the value in counter 352A does not exceed
the value in counter 352B, and accordingly a false signal is appearing on line 364.
With the false signal on line 364 and a true signal on line 350, the EOR 330 produces
a true output which is clocked into flip-flop 332 by the occurrence of the leading
edge of the encoder pulse at time T = 18. This clocking in of the true signal from
EOR 330 causes output pin Q of flip-flop 332 to go false.
[0100] A false signal at output pin Q of flip-flop 332 basically accomplishes two things.
First, it applies a false signal to pin 12 of the EOR 328 which causes the output
of EOR 328 to go true. The true output from EOR 328 puts counter 352B in the reset
state and makes it further impossible for comparator 326 to find if the contents of
counter 352A exceed the value of counter 352B. Secondly, the false signal at output
pin Q of flip-flop 332 causes (by the action of inverter 370) a true signal to be
placed on line 372 and the actuator timing bus 336. As seen hereinafter, the true
signal on actuator timing bus 336 results in a substantially undelayed engaging actuation
of the jaw members of each of the gripper jaws 16 of the insertion machine.
[0101] In the above regard, the station presettable release delay means 338 have no significant
delay impact upon engaging actuation of the jaw members. The true signal on actuator
timing bus 336 results in a true signal being applied to the preset enable pin (pin
7 of the shift register 386) and to the input terminal of the inverter 381. While
the true signal is applied to pin 7 of the shift register 386 the register 386 is
preset with the binary value indicated by the dial on its respective thumbwheel switch
387. As long as the register 386 is being preset, the Q output terminal remains true.
During this time, however, the output terminal of driver 381 goes false, ultimately
causing the driver transistor 388 to conduct. As each of the driver transistors 388
associated with the respective insert stations conducts, the solenoids 28 at the respective
insert stations are actuated. The actuation of solenoid 28 creates a force on cable
206 to move cable 206 in an upwards direction, thereby closing a jaw 26 to engage
an insert between the jaws 24 and 26. The amount of force created by the solenoid
depends upon such factors as the force curve for the particular solenoid used and
its duty cycle. In this regard, the nature of the force curve for the embodiment under
discussion will be understood by reference to European Patent Specification EP-A-0174214
previously referred to.
OPERATION CONTROLLING RELEASING ACTUATION OF GRIPPER JAWS
[0102] At time T = 59 a pattern on the circumference of the actuator timing disc obstructs
the passage of light from the LED 308 to the receiver 310. This obstruction of light
basically occurs at points in the machine cycle in which it is desired for the second
jaw 26 to open with respect to the jaw 24 as a result of the actuator activation.
For reasons such as the operating speed of the machine and the different sizes of
the inserts at the insert stations, some delay is required between the point at which
the actuator timing disc begins to obstruct light and the actual deactivation of the
actuator means so that the gripper jaws 16 release inserts so that the inserts can
be deposited on the insert track. As discussed above, the release delay time can have
as many as three delay components. The first release delay component is determined
by the master presettable release delay means 322 which impacts all insert stations
to reflect the position of the side rail SR1 relative to the row of insert stations
(i.e. to reflect the width of the insert track). The second release delay component
is the machine operating speed dependent release delay which also impacts all insert
stations and which basically resembles the speed dependent engagement delay described
above. The third release delay component is individually determined for each insert
station by that insert station's presettable release delay means 338. Thus, while
the master preset release delay component and the speed dependent release delay component
are essentially the same for all insert stations, the station preset release delay
component varies from station to station. The magnitude of the station preset release
delay for each station is dependent upon the value selected on the station's thumbwheel
switch 387. In the example under discussion, thumbwheel switch 387A for insert station
S1 has been set to 2; thumbwheel switch 387B for the very large inserts at insert
station S2 has been set at 8; and, thumbwheel switch 387C for average size inserts
at insert station S3 has been set at 1.
[0103] When at time T = 59 the actuator timing disc begins to preclude the passage of light
from LED 308 to photoreceiver 310, the master preset release delay caused by means
322 first occurs, followed by the speed dependent release delay, followed by the station
preset release delay. Inasmuch as the binary input values from thumbwheel switch 387
indicates the number of encoder pulses which constitute the station preset release
delay, it is understood that the actual release of an insert from gripper jaw 16₁
of station S1 occurs two encoder pulses after the speed dependent release delay; the
release of inserts from gripper jaw 16₂ of station S2 occurs eight encoder pulses
after the speed dependent release delay; and, the release of inserts from the gripper
jaw 16₃ of station S3 occurs one encoder pulse after the speed dependent release delay.
[0104] As mentioned above, the first release delay component is the master presettable release
delay occasioned by means 322. In this respect, when at time T = 59 the actuator disc
precludes passage of light from LED 308 to photoreceiver 310, the output of the actuating
timing NAND 318 goes false, thereby applying a false signal on line 319 and 343. The
false signal on line 319 has no impact on the set terminal of flip-flop 323, and hence
no effect on the EOR 350, meaning that a true signal is applied to the reset pin of
counter 352B. The true signal at the reset pin of counter 352B precludes counter 352B
from counting and hence does not permit the counter means 324 and comparator means
326 to begin implementation of the operating speed dependent release delay component.
[0105] The false signal applied to the preset enable pin of the down counter 342 causes
the counter 342 to start counting down with the reception of leading edges of encoder
pulses at its clock input pin. In the example under discussion with the master delay
thumbwheel switch 344 set to a 2 value, the presettable down counter 342 is preset
so that its contents is "2". At the leading edge of the next occurring encoder pulse
(at time T = 60) the counter 342 is decremented from "2" to "1". The leading edge
of the very next encoder pulse (time T = 66) causes the counter 342 to decrement from
"1" to "0".
[0106] When the contents of counter 342 reaches "0" the signal at the carryout pin (pin
7) goes false, causing the output of EOR 346 to finally go true. The true going output
of EOR 346 enables flip-flop 323 to clock in a false signal which results in a false
signal being applied from output pin Q to line 350. It is thus seen that the master
preset switch release delay means has provided a release delay component from time
T = 59 to time T = 68 prior to the institution of any other release delay components.
[0107] A false signal on line 350 makes possible the generation of the operation speed dependent
release delay component. In this respect, the false signal on line 350 causes the
output of EOR 328 to go false, thereby removing the reset from counter 352B. Counter
352B can then start counting the trailing edges of encoding pulses, which it does
beginning at the time T = 68. As described with reference to the speed dependent engagement
delay, the trailing edges of the encoding pulses also activates the clock 320 so that
counter 352A can count clock pulses on line 356 as long as lines 315 and 341 are false.
In similar manner as described with reference to the speed dependent engagement delay,
the comparison means 326 puts a true signal on line 364 whenever the contents of counter
352A exceeds the contents of counter 352B. When upon the application of a leading
edge of an encoding pulse to the flip-flop 332 it is also determined that the contents
of counter 352A does not exceed the contents of counter 352B, the flip-flop 332 fires
a low pulse at the Q output terminal. As seen in Fig. 4B, this does not occur until
three encoder pulses after the counter 352B has started counting. That is, flip-flop
332 switches state at time T = 84 to produce a true signal at the Q output pin. Thus,
the counter means 352 and the comparator 326 working together cause a speed dependent
release delay which occurs from time T = 69 to time T = 84.
[0108] The change of state of the flip-flop 332 accomplishes two basic results. First, the
true signal at pin 2, coupled with the false signal on line 350, causes the output
signal of EOR 328 to go true. The true output of EOR 328 resets counter 352B and precludes
the comparator 326 from reaching a determination that the contents of counter 352A
is greater than the contents of counter 352B. Second, a change of state of the flip-flop
332 causes the driver 370 to put a false signal on line 372 and the actuating timing
bus 336.
[0109] The false signal on actuator timing bus 336 eventually activates the actuator means
at each of the insert stations, but not before the station presettable release delay
means 338 of the respective insert stations has had an opportunity to further delay
activation by the preset release delay component indicated on the corresponding station's
thumbwheel switch 387. As pointed out before, the delay occasioned by each station
presettable release delay means is independently input using the thumbwheel switches
387 for the respective stations. The operation of only one such station presettable
release delay means, particularly means 338A for station S1, is described in detail
hereinafter, the operation of the remaining delay means 338B and 338C being understood
from the discussion of the one station S1.
[0110] The false signal on actuator bus 336 results in a false signal being applied both
to the preset enable input pin (pin 7) of the presettable shift register 386 and to
the input terminal of the inverting driver 381. When pin 7 of the shift register 386
receives a low signal, the register 386, whose length was preset in accordance with
the value selected on thumbwheel switch 370A (in our example, a binary 2), begins
to shift as leading edges of encoder pulses are received at clock input pin 4. In
this respect, the encoder pulses are applied on lines 315, 374, bus 334, and by the
driver 384 and the NAND gate 385 to pin 4 of the presettable shift register 386.
[0111] With the reception of the leading edge of the next encoder pulse (occurring at time
T = 90) the shift register makes a first shift. Since the register 386 for means 338A
was preset to a length of binary 2, the register 386 still has some value and the
Q output pin remains true. At the reception of the leading edge of the next encoding
pulse (time T = 96), however, the shift register 386 has been completely shifted through
its length and the output pin Q accordingly goes false. The false-going output from
pin Q of register 386 causes the driver 382 to apply a true signal to driver 383.
A false output signal from the inverting driver 383 causes the driver transistor 388
not to conduct, whereby the solenoid 28 associated with gripper arm 16₁ for insert
station S1 is deactivated. Deactivation of the jaw actuator means that the plunger
92 is free to fall downwardly, as does the linkage 30. Downward action of the linkage
30 causes the second jaw member 26 to pivot about pivot pin 178 in a direction away
from the first jaw member 24.
[0112] From the foregoing it is seen that the third release delay component, the station
preset release delay component, occurs for station S1 from the time T = 84 to the
time T = 96. The station preset release delay for station S1 is of a duration corresponding
to the value selected on terminal switch 387A. For station S1 the station preset release
delay component corresponds to two encoder pulses as indicated by the dial setting
on thumbwheel switch 387A. Because the dial setting on thumbwheel switch 387B of station
S2 is significantly greater (8), gripper arm 16₁ associated with the station S2 releases
the much larger insert at station S2 after a significantly longer station preset release
delay. Gripper arm 16₃ associated with insert station 53, however, releases its average
size inserts at an earlier time (T = 90) in view of the dial setting at 1 on thumbwheel
switch 387C.
[0113] Fig. 5A is a timing diagram showing electrical values for only various ones of the
components shown for Figs. 4A and 4B and for only the time period T = 58 through T
= 100. Fig. 5A shows the release delay time components for an insertion machine operating
at the speed of about 4,000 machine cycles per hour, and particularly shows the release
delay time components for the gripper jaw 16₁ of station S1. Fig. 5B depicts the release
delay components for the gripper jaw 16₁ of the same machine when it is operating
at about 8,000 machine cycles per hour. Master delay thumbwheel switch 344 is set
at 2 and the station delay thumbwheel switch 387 is set at 2 in the operating modes
of both Figs. 5A and 5B. Accordingly, it is noted that the master preset release delay
component for both the slower and the faster modes are related to the setting of thumbwheel
switch 344 (i.e. two encoder pulses), and the station preset release delay component
of the both the slower and the faster modes are related to the setting of the station
delay thumbwheel switch 387 (i.e. two encoder pulses). The speed dependent release
delay component for the two modes differs. In the slower mode of Fig. 5A it is seen
that the speed dependent release delay component duration is about three encoding
pulses, whereas in the faster mode of Fig. 5B the speed dependent release delay component
duration is about two encoding pulses.
EPILOGUE
[0114] From the foregoing it is seen that an advantage of the invention is making the time
at which the jaw actuator is selectively activated and deactivated dependent upon
the speed in conjunction with which the gripper arm operates. Less delay for the deactivation
of the actuator is required at higher machine operating speeds than lower machine
operating speeds for the gripper arm 16 to carry out operations that result in precise
placement of an article engaged and released by a gripper arm. By making the time
of the deactivation of the jaw actuator dependent upon the speed of the machine, an
operator can set up a machine in a slow jog mode for a gripper arm to deposit an insert
at a precise location on transport means such as the insert track with confidence
that when the machine is operating at a higher speed essentially the same precise
placement of the article will occur.
[0115] From the foregoing it is also seen that the present invetion allows an operator to
control insert release time in order to provide appropriate release delay time components
to compensate for adjustment to insert track width and/or to compensate for insert
size. In the foregoing example, for instance, it has been presumed that inserts I₂
at station S2 were so large as to necessitate widening insert track 18 by adjustment
not only of side rail SR1. In other situations in which side rail SR1 need not be
moved to widen the track, the master delay thumbwheel switch 344 can be set to a 1
value so that a minimum preset release delay component occurs. The operator may make
appropriate compensation for insert size individually at stations requiring compensation
by selecting an appropriate value on the requiring station's thumbwheel switch 387
in order to occasion a station presettable release delay component. At any time including
during operation any station's individual station presettable release delay component
can be changed to fine tune placement of that station's inserts on the insert track
18.
[0116] While the invention has been particularly shown and described with reference to the
preferred embodiments thereof, it will be understood by those skilled in the art that
various alterations in form and detail may be made therein without departing from
the scope of the claims.
1. Beschickungsmaschine (10) mit einer Mehrzahl von Beschickungsstationen (S₁, S₂, S₃),
an denen Vorräte von Beschickungsmaterial (I₁, I₂, I₃) zumindest zeitweise gespeichert
sind, ferner mit einer Beschickungsbahn (18), welche längs der genannten Mehrzahl
von Beschickungsstationen intermittierend bewegt wird, um auf sie abgelegtes Beschickungsmaterial
zu transportieren, weiter mit Greiferarmen (16₁, 16₂, 16₂), welche einer Anzahl von
Beschickungsstationen zugeordnet sind und welche jeweils ein erstes Klauenelement
(24) und ein zweites Klauenelement (26), das selektiv gegenüber dem ersten Klauenelement
zum Greifen von Beschickungsmaterial dazwischen bewegbar ist, sowie Mittel (28) enthält,
um slektiv das erste und zweite Klauenelement in eine erste Stellung zu bewegen, in
der Beschickungsmaterial zwischen den Klauenelementen festgehalten wird, und in eine
zweite Stellung zu bewegen, in welcher das Beschickungsmaterial zwischen den Klauenelementen
freikommt und auf die Beschickungsbahn abgelegt wird, und mit Mitteln (300 - 390)
zur Steuerung der genannten Mehrzahl von Betätigungsmitteln derart, daß die Betätigung
jedes der Greiferarme zum Freigeben von Beschickungsmaterial steuerbar ist, wobei
die Beschickungsmaschine dadurch gekennzeichnet ist, daß die genannten Steuermittel
eine Mehrzahl von Station zu Station voreinstellbarer Zeitgebermittel (338A, 338B,
338C) enthält, so daß für jeden der Greiferarme eine unabhängige Zeitkomponente vorgesehen
werden kann, welche zu einer Eigenschaft des Beschickungsmaterials an der zugehörigen
Beschickungsstation entsprechend einer Anzeige eines zugehörigen vorgegebenen Eingabewertes
in Beziehung steht.
2. Beschickungsmaschine nach Anspruch 1, bei welcher die Mittel zur Steuerung der genannten
Mehrzahl von Betätigungsmitteln weiter voreinstellbare Haupt- Verzögerungsmittel (322)
enthalten, derart, daß für die genannte Anzahl von Greiferarmen eine gleichförmige
Zeit-Freigabekomponente entsprechend einem vorbestimmten Eingabewert vorgesehen ist.
3. Beschickungsmaschine nach Anspruch 1, bei welcher die Mittel zur Steuerung der genannten
Anzahl von Betätigungsmitteln weiter Einrichtungen zum Einschalten und Abschalten
der genannten Betätigungsmittel in Abhängigkeit von einem Maschinenzyklus enthalten,
gemäß welchem die Beschickungsmaschine arbeitet, wobei die Maschine mit einer veränderbaren
Geschwindigkeit von Maschinenzyklen je Zeiteinheit betrieben werden kann und wobei
die Einrichtungen zum Einschalten und Abschalten der Betätigungsmittel in Abhängigkeit
vom Maschinenzyklus folgende Teile enthalten:
erste Sensormittel (300) zur Bestimmung der Maschinenzyklusgeschwindigkeit und zur
Erzeugung entsprechender Kodierungsimpulse;
zweite Sensormittel (306) zur Bestimmung des Zeitpunktes, zu dem während jedem Maschinenzyklus
die besagten Betätigungsmittel einen Übergang von der selektiven Einschaltung oder
Ausschaltung durchführen sollen;
Taktgebermittel (320) zur Erzeugung von Taktimpulsen mit einer vorbestimmten Frequenz
und
Mittel zur Bestimmung, nachdem besagte zweite Sensormittel angezeigt haben, daß genannte
Betätigungsmittel einen Übergang durchführen sollen, eines Zeitpunktes, zu welchem
die Anzahl der Kodierungsimpulse eine bestimmte Beziehung zu der Anzahl von erzeugten
Taktimpulsen haben und zur Übermittlung der Bestimmung des geannten Zeitpunktes an
die Betätigungsmittel.
4. Beschickungsmaschine nach Anspruch 3, dadurch gekennzeichnet, daß die Mittel zur Bestimmung
des genannten Zeitpunktes weiter folgende Teile enthalten:
erste Zählermittel (352B) zur Zählung der Anzahl von Taktimpulsen, welche zwischen
aufeinanderfolgenden Kodierungsimpulsen auftreten,
zweite Zählermittel (353A) zur Zählung der Anzahl von Kodierungsimpulsen, welche nach
Angabe der genannten zweiten Sensormittel dahingehend auftreten, daß die genannten
Betätigungsmittel einen Übergang bewirken sollen,
Vergleichseinrichtungen (326) zum Vergleich der Zählung der ersten Zählermittel und
der Zählung der zweiten Zählermittel und zur Erzeugung eines Signales entsprechend
dem Vergleichsergebnis und
Multivibratormittel (332), welche an die Vergleichseinrichtungen angeschlossen sind
und so ausgebildet sind, daß sie ein Signal erzeugen, wenn immer die vorbestimmte
Beziehung festgestellt wird.
5. Verfahren zum Betrieb einer Beschickungsmaschine (10) einer Bauart, bei welcher eine
Beschickungsbahn (18) einstellbarer Breite intermittierend an einer Mehrzahl von Beschickungsstationen
(S₁, S₂, S₃ ) vorbeibewegt wird, wobei die Anzahl von Beschickungsstationen jeweils
Greiferarme (16₁, 16₂, 16₃) aufweist, die jeweils den Stationen zugeordnet sind, um
Beschickungsmaterial (I₁, I₂, I₃) an den Beschickungsstationen zu greifen und um das
besagte Beschickungsmaterial freizugeben, derart, daß dieses auf die Beschickungsbahn
gesetzt wird, wobei das Verfahren folgende Schritte enthält:
Feststellen des Zeitpunktes innerhalb eines Maschinenzyklus der Beschickungsmaschine,
zu welchem die genannte Anzahl von Greiferarmen Beschickungsmaterial, welches von
ihnen gehalten wird, freigeben sollen,
Betätigen der genannten Greiferarme zum Freigeben des Beschickungsmaterials zum Aufsetzen
auf die Beschickungsbahn zu einer Betätigungszeit, welche zu dem genannten festgestellten
Zeitpunkt des Maschinenzyklus in Beziehung steht,
Prüfung, für jede der genannten Beschickungsstationen, ob die Betätigung zu einer
ordnungsgemäßen Plazierung des Beschickungsmaterials auf der Beschickungsbahn führt,
wobei das Verfahren gekennzeichnet ist durch folgende Schritte:
Veränderung der Beziehung der genannten Betätigungszeit relativ zu dem Zeitpunkt des
Maschinenzyklus für einzelne der Beschickungsstationen, an denen das Aufsetzen des
Beschickungsmaterials auf die Beschickungsbahn nicht ordnungsgemäß war, derart, daß
die geänderte Beziehung zu einem richtigen Aufsetzen des Beschickungsmaterials an
den genannten einzelnen der Beschickungsstationen auf der Beschickungsbahn führt.
6. Verfahren nach Anspruch 5, weiter gekennzeichnet durch folgende Verfahrensschritte:
Laden der genannten Anzahl von Beschickungsstationen mit Beschickungsmaterial,
Einstellen der Breite der genannten Beschickungsbahn unter Berücksichtigung der Größe
des größten Beschickungsmaterials an den Beschickungsstationen,
Bestimmung für mindestens diejenige Beschickungsstation, an der die genannten größten
Beschickungsmaterialen gespeichert sind, ob eine bestehende Beziehung zwischen einer
Freigabebetätigungszeit für das Beschickungsmaterial und einer gemessenen Freigabezeit
zu einer ordnungsgemäßen Plazierung des genannten größten Beschickungsgutes auf der
Beschickungsbahn führt, wobei die gemessene Freigabezeit einem periodisch auftretenden
Zeitpunkt des Maschinenzyklus der Beschickungsmaschine entspricht und wobei
der genannte Verfahrenssschritt des Änderns der Beziehung der Betätigungszeit relativ
zu dem genannten Zeitpunkt des Maschinenzyklus darin besteht, daß die Beziehung der
Freigabebetätigungszeit relativ zur gemessenen Freigabezeit für mindestens die besagte
Beschickungsstation geändert wird, in der die größten der Beschickungsmittel gespeichert
sind, wodurch die geänderte Beziehung in der ordnungsgemäßen Plazierung mindestens
der größten der Beschickungsgegenstände auf der Beschickungsbahn resultiert.
7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß die genannte Beziehung der
Freigabebetätigungszeit relativ zur gemessenen Freigabebetätigungszeit für sämtliche
Beschickungsstationen gleichförmig verändert wird.
8. Verfahren nach Anspruch 7, gekennzeichnet durch weitere folgende Verfahrensschritte:
Bestimmen, für jede der genannten Beschickungsstationen, ob die genannte Änderung
der Beziehung der Freigabebetätigungszeit relativ zur gemessenen Freigabebetätigungszeit
zu einer ordnungsgemäßen Plazierung jedes des Beschickungsmaterials auf der Beschickungsbahn
führt und
weiteres Ändern der Beziehung der Freigabebetätigungszeit relativ zur genannten gemessenen
Freigabebetätigungszeit für einzelne der Beschickungsstationen derart, daß die weiter
geänderte Beziehung in einer besseren Plazierung des genannten Beschickungsmaterials
von den einzelnen der Beschickungsstationen auf die genannte Beschickungsbahn resultiert.