OBJET OF THE INVENTION
[0001] The present invention relates to a step-by-step activation system, with a choice
of stop intervals of variable lengths, applicable to program control devices, of the
sort used in automatic washing machines, dishwashers and tumble driers, which devices
comprise a block or set of fast cams which rotate continuously and assist contacts,
where provided, which govern periodic functions in such machines, for instance reversing
the direction of rotation of the washing drum, the said devices also having a block
or set of main or program cams, the various working phases of the machines being governed
through the said contacts, the block of fast cams being generally uniformly and steadily
activated whereas the main block is driven step by step, with stop intervals every
two step movements of variable lengths.
BACKGROUND OF THE INVENTION
[0002] It is a well-known fact that the larger the number of stop intervals obtainable,
the bigger the capacity to program a control device, which is why the systems generating
these are continually being improved, and a large number of varied solutions have
been put forth in time.
[0003] Reference could for instance be made to French patent 1,595,564 where the block of
program cams is designed with an integral ring gear activated by a pawl which makes
it move one step forward each time it engages with the ring gear. Whenever the program
so provides, a lock prevents the pawl from engaging with the ring gear integral with
the block of cams, remaining thus until a timer element or wheel determines otherwise.
The lock is part of a pivoting lever with a probe which works, assisted by the appropriate
elastic means, with a selector cam that is also integral with the block of program
cams. The timer element or wheel also has a surface that removes the lock from its
active position when the pre-set time is over.
[0004] Italian patent 21,953 A/67 relates to a system similar to the above, singular in
that the timer element or wheel is coaxial with the blocks of fast and program cams
and also has means to reset the timer element to zero each time the block of program
cams moves one or more steps forward, resetting being triggered by the element which
accurately positions the block of main cams angularly.
[0005] Reference can also be made to German patent 1,193,008 in which the ratchet that prevents
the timer wheel, which is continuously acted upon by elastic means, from returning
toward it each time it moves forward, is rendered inactive when the preset time is
over and held in such position until the pawl that makes it move forward step by step
is also separated from the ring gear, both actions therefore allowing the timer wheel
to be reset to zero, whereupon the anti-return ratchet is immediately released, becoming
active again.
[0006] The original arrangement and combination of the above and other known elements, such
as ring gears with various levels of cogs, swinging or overlapping timer wheels and
so on, have resulted in the aforesaid current choice of solutions.
[0007] Italian patent 1179717 thus relates to a device which yields two stop intervals for
the block of program cams with one of its constituent parts, one of which lasts no
more than the period of rotation of the block of fast cams, and the second one a fraction
of this latter, whereas another part allows the previous and longer interval to be
multiplied by whole multiples.
[0008] Operation relies upon an actuation pawl of periodic to-and-fro motion and means which
prevent it from acting on the ring gear in the block of program cams for the time
being. Such means in part comprise a timer element or wheel coaxial with the blocks
of cams, provided with the appropriate holding and release means for the said timer
wheel to be reset to zero, and a detent that, in co-ordination with the timer wheel
and where appropriate, prevents the actuation pawl from engaging the block of program
cams.
[0009] The disadvantage of the system is that the difference between both timings of length
equal to or a fraction of the period of rotation of the block of fast cams, and the
intervention or otherwise of the multiplier mechanism, depend, inter alia, on the
active area within reach of the actuation pawl having the high or low level cogs of
a two-level ring gear coupled to the block of program cams, wherefore the timing possibilities
are limited to the said four.
DESCRIPTION OF THE INVENTION
[0010] The activation system subject hereof is designed to achieve step-by-step activation
of a block of program cams with a choice of stop intervals of variable length, also
partially relying on a timer wheel coaxial with the cam blocks and a detent which
is particularly convenient and which on the one hand makes a timing of maximum length
possible for the period of rotation of the fast cams, and two fractions thereof, and
on the other, multiplication or otherwise of either of them by two multiplication
factors, thereby simply and reliably to obtain nine stop intervals of different lengths,
which means that use is very flexible, according to the needs that arise nowadays
in machines for which such system is designed.
[0011] The system essentially comprises a motor and a transmission that provide a block
of fast or reversing cams with motion, such cams rotating continuously at a steady
speed, and a cam wheel which rotates to produce a steady to-and-fro motion in an advancing
pawl. The system is also provided with a block of main or program cams, which moves
forward step by step each time the actuation pawl acts upon a ring gear with which
it is integral, and a timer system which acts following a pre-set program, temporarily
preventing the actuation pawl from moving the block of program cams forward each time
it undergoes a to-and-fro motion, the timing system comprising two subsystems that
may act separately or in combination, one such subsystem being designed to achieve
stop intervals lasting the same as the period of rotation of the block of fast cams
or fractions thereof, and the other subsystem being designed to multiply the length
of any of the foregoing intervals by a factor whose magnitude is defined by a timer
wheel or cam placed between the two blocks of cams, coaxially therewith, with freedom
of rotation.
[0012] Such timer wheel or cam has the usual elements required for normal operation, such
as activation and deactivation elements, elastic means urging it to start running,
holding means preventing it from being reset to zero during the pre-set time, and
means to position and keep such holding elements inactive to allow the timer wheel
to return to the starting point each time the block of program cams moves one or more
steps forward, and again position the same ready to act once reset to zero. It also
has a detent or like element which works with the timer wheel and is designed to obtain
a second factor multiplying the times from the first subsystem, on preventing the
actuation pawl from penetrating a first deep space in the timer wheel's time counter
ring gear, corresponding to the first multiplication factor, thereby preventing the
actuation pawl from engaging the ring gear of the block of program cams, when the
said deep space comes within reach of the pawl, the timer wheel having a surface which
displaces the masking element at the end of its longer pre-set time, beyond its active
position, leaving the system ready for the block of program cams to move one step
forward.
[0013] Attached to the masking element are the means allowing the second multiplication
subsystem to be activated and deactivated, and a probe which, with the assistance
of elastic means, follows a three-level selector cam profile located inside the block
of program cams, so that when the probe detects the level of greatest radius, the
said subsystem is inactive, at the middle level the timer wheel is active and the
lock inactive, which state corresponds to the first multiplication factor, whereas
at the level of smallest radius, both the timer wheel and the lock are active, which
state corresponds to the second multiplication factor.
[0014] The mechanisms of the activation, timing and positioning systems of the block of
program cams are all assembled on a support plate located between the two blocks of
cams.
[0015] In addition to this basic and conventional structure, the system subject hereof has,
as a feature of the invention, an actuation pawl that is provided with to-and-fro
motion by a cam wheel which rotates continuously, the said pawl being urged by suitable
elastic means towards the ring gears in the block of program cams and towards the
counting ring gear in the timer wheel, the said pawl also having means which lift
the same when it moves back, drawing it away from the aforesaid two ring gears.
[0016] With reference to another feature of the invention, the free end of the actuation
pawl can work with the free end of a swinging detent that can take up two positions,
one in which it stands in the way of the pawl, preventing it from engaging the aforesaid
ring gears each time it undergoes a to-and-fro motion, whilst in the other position
it remains at a distance, allowing the pawl to act freely.
[0017] The detent's position is in turn defined by a likewise swinging clearance lever with
three working positions. At the two end positions, it holds the detent out of the
reach of the actuation pawl, whereas in the middle position it stands in its way.
[0018] This clearance lever, located between both blocks of cams, has two probes which are
assisted by appropriate elastic means to connect with the same number of internal
cam profiles, both having three levels, one being a selector profile in the block
of program cams, and the other an activation profile, located in the block of reversing
cams.
[0019] With reference to another feature of the invention, each of the three levels of the
selector cam of the block of program cams governs a time of inactivity of the actuation
pawl of different length. Thus at the level of smaller radius, a length equal to the
period of oscillation of the actuation pawl, for instance 7.5 seconds, is obtained,
at the middle level the length can at most be equal to the period of rotation of the
block of fast cams, for instance 4 minutes, the duration at the level of greatest
radius being equal to a fraction of the latter, for instance 1/2, 1/3, 1/4 and so
on.
[0020] The profile located at the block of fast cams which rotates continuously with the
same must cause the detent to swing, making it hold or release the actuation pawl
at the appropriate times, as defined by the shape of the actual profile and by the
level of the selector cam at which the relevant probe can be found. Save where the
block of program cams is in a short timing position, in which case it is actually
its own selector cam profile which acts through its level of lower radius on the clearance
lever to cause direct release of the actuation pawl.
[0021] It is then possible for the actuation pawl to act, when the detent is released, on
the block of program cams, making it move one step forward, or otherwise a second
part of the system to intervene delaying such action. This second part or subsystem,
which has already been generically described, has the following peculiarities.
[0022] When the element or timer wheel is at rest, it lies beyond the reach of the actuation
pawl, in a stand-by position defined by a fixed abutment toward which it is urged
permanently by suitable elastic means, activation coming about when the anti-return
ratchet, in moving to engage the ring gear holding the timer wheel, acts on a surface
arranged as a ramp on the said wheel, causing the same to move angularly beyond the
reach of the actuation pawl, about to start its pre-set time.
[0023] A selector lever, whose probe is assisted by the relevant elastic means to follow
a three-level cam profile in a second selector cam disposed inside the block of program
cams, has a holding surface so that when the lever probe is at the level of greater
radius, it keeps the anti-return ratchet at a distance from the relevant ring gear
in the timer wheel, allowing it to reach the same once it is on either of the other
two levels.
[0024] With reference to another feature of the invention, the anti-return ratchet in the
timer wheel has an elastic arm whose free end works with a fixed abutment so that
when the holding ratchet moves away from its corresponding ring gear on the timer
wheel, each time the block of program cams moves one step forward, it holds the same
in such position for the time required for the actuation pawl, which is lifted as
it moves back, also to move away from its appropriate ring gear on the timer wheel,
both actions together permitting its being reset to zero. A peripheral protuberance
on the cam wheel acts shortly after on the elastic arm, moving it out of its holding
position and hence leaving the holding ratchet in the timer wheel free to act again.
[0025] Finally, and with reference to another feature of the invention, in activating, timing
and positioning, the block of program cams only has a single ring gear, all the cogs
being at the same level. The timer wheel ring gear, working with the foregoing, is
at a radially higher level and has, in specific positions, spaces of greater depth
that enable the actuation pawl to engage the said ring gear in the block of program
cams.
DESCRIPTION OF THE DRAWINGS
[0026] In order to provide a fuller description and contribute to the complete understanding
of the characteristics of this invention, a set of drawings is attached to the specification
which, while purely illustrative and not fully comprehensive, shows the following:
Figure 1.- Is a plan view of a timer switch provided with the activation system subject
hereof, with the detent activated.
Figure 2.- Is a section of the said timer switch.
Figures 3, 4 and 5.- Respectively show details of the three positions of the clearance
lever, duly connected to the detent with the actuation pawl, likewise showing the
program and fast cam profiles.
Figure 6.- Is a plan view of the timer switch, as in figure 1, but without the timer
cam in order for the mechanisms located under the same to be seen in greater detail.
Figures 7 to 13.- Finally show the various working positions of the timer cam together
with the selection lever and the anti-return ratchet, and their connection to the
actuation pawl catch and the ring gear in the block of program cams.
PREFERRED EMBODIMENT OF THE INVENTION
[0027] It can in light of these drawings be appreciated that a motor and a transmission
that are not shown in such figures generate, in a manner that is known per se, a steady
rotary movement supplied to a block of fast cams (1) and an eccentric cam (2). This
eccentric cam (2) in turn provides a steady to-and-fro motion to an actuation pawl
(3) having a catch (4), which engages, when the timing means so allow, a uniform ring
gear and cogs (5) located on a single level, integral with the block of program cams
(6), causing it to move forward step by step.
[0028] The actuation pawl has an extension whose end (7) can under certain operating circumstances
engage the end (8) of a swinging detent (9), the cogs (5) thus remaining beyond the
reach of the actuation pawl's catch (4), as may be observed in figures 1 and 5.
[0029] The detent (9) can in turn take up the positions shown in figures 3 and 4 and in
figure 5, thereby allowing the catch (4) to engage the cogs (5) in one such position
(figures 3 and 4) and preventing such engagement in the other position, shown in figure
5.
[0030] A spring (10) drives the actuation pawl (3) towards a position of engagement with
the cogs (5), and the detent (9) towards a position of engagement with the end (7)
of the actuation pawl.
[0031] The position of the detent (9) is defined by a spigot (11) thereof which feels a
cam profile (12) located on the free end of a likewise swinging clearance lever (13),
specifically swinging about the spin axis (14), the clearance lever being able to
take up three working positions, respectively shown in figures 3, 4 and 5.
[0032] The clearance lever (13), located between the blocks of fast (1) and program (6)
cams, as is clearly appreciated in figure 2, has two probes (15) and (16) with one
of these, number (15), following an internal cam profile (17) along three levels,
in the block of program cams (6), the other one, number (16) being related to an internal
cam profile (18) also along three levels, integral with the block of fast cams (1).
A spring (19) must keep the probes in touch with the respective aforesaid cam profiles.
[0033] The cam profiles are shown figuratively in figures (3), (4) and (5), for their movement
is obviously circular.
[0034] As shown in figure 3, when the probe (15) rests at the level of greatest radius (20)
on the cam profile (17) of the block of program cams, the clearance lever (14) will
act upon the detent (9) causing the end (8) thereof to move away from the actuating
pawl end (7) whenever the probe (16) is in an area of the cam profile of greater radius
(21) or smaller radius (22), such position corresponding to a timing equal to a fraction
of the period of rotation of the block of reversing cams, the denominator of the fraction
depending on the number of elevations and depressions present on the cam profile (18).
[0035] When the probe (15) is at the level of smaller radius (23) on the profile (17) in
the block of program cams, as shown in figure 4, this same profile positions, without
the assistance of the profile (18) in the block of fast cams, the system in the active
state, corresponding to a short timing, of length equal to that of the period of to-and-fro
motion of the forward pawl (3), for instance, and as aforesaid, 7.5 seconds.
[0036] In the working position shown in figure 5, the system will only be activated when
a protuberance (24) on the cam profile (18) in the block of fast cams, moves the probe
(16) carrying the clearance lever (13), and the latter the detent (9) to the position
shown in figure 4. In such event, and in the event of the cam profile (18) having
only one protuberance (24) on its periphery, the timing obtained will last as much
as the period of rotation of the block of fast cams.
[0037] When the above-described timing system allows the actuating pawl (3) to go near the
ring gear (5) in the block of program cams, it can either act on the same, causing
a step or angular movement equivalent to that existing between two adjacent cogs to
be advanced, or else a second part of the timing system function to multiply the length
of the timings by one or two of the pre-set factors.
[0038] This second part of the system comprises a selector lever (25), a timer lever (26)
and an anti-return ratchet (27) in the timer cam. The selector lever, shown in figures
1 and 6, is provided with a probe (28) to follow an internal cam profile (29) along
three levels, integral with the block of program cams (6).
[0039] When the selector lever's probe (28) is at the cam (29) level of greater radius,
the free end (30) of the selector lever, and the timer cam, is drawn away, as shown
in figures 7 and 8, thus allowing the catch (4) in the actuating pawl (3) to act upon
the cogs (5) in the block of program cams. In such position, a support surface (31)
of the selector lever (25), as shown in figure (6), prevents the anti-return ratchet
(27) from moving towards the holding cogs (32) in the timer cam (26), toward which
it is urged by a spring (33).
[0040] When the probe (28) in the selector lever moves into any of the other two levels
of smaller or medium radius on the cam profile (29), the support surface (31) is no
longer flush with the anti-return ratchet (27) allowing the latter to engage the holding
cogs of the timer cam. In order for this to take place it is also necessary for a
salient (34) on the eccentric cam to push the probe (35) in the elastic arm (36) of
the anti-return ratchet (27) in order to release the same from an abutment (37) provided
on the supporting plate (38), upon which they are assembled. When this happens, the
catch (40) in the anti-return ratchet acts, on falling upon a ramp (41) of the timer
cam (26), moving forward and carrying the system in the position shown in figure 9.
[0041] As shown in such figure 9, the first cog (39) in the timer cam is placed within reach
of the catch (4) in the actuating pawl, preventing it from reaching the ring gear
(5) in the block of program cams (6), since the ring gear (39) in the timer cam is
located at a level above the ring gear (5) in the block of program cams. The end (30)
of the selector lever (25) remains beyond the reach of the actuating cam (4). Under
these circumstances, the timer cam (26) moves forward step by step until a deeper
space (42) comes within its reach, as shown in figure 11, allowing the catch (4) to
penetrate to reach the ring gear (5) in the block of program cams, causing the latter
to move one step forward. Thus, operation corresponds to a position of the selection
lever (25) where its probe (28) is located on the middle level of the cam profile
(29) thereof, thereby to achieve a multiplication factor equal to the number of cogs
provided between the first cog (39) in the timer cam and the first deep space (42).
[0042] When the probe (28) in the selector lever (25) is located at the level of smaller
radius on the cam profile (29), the end (30) of the selector lever is positioned within
the scope of the catch (4), as shown in figure 12. The catch (4) then causes the timer
cam to move forward step by step, but the end (30) of the selector lever (25) prevents
it from entering the first deep space. The timer cam continues to move forward until
a drive surface (43) provided thereon acts on a spigot (44) integral with the selector
lever (25), displacing the end (3) thereof to a position beyond the reach of the catch
(4), as shown in figure 12. The catch (4) then enters the second deep space (45) in
the ring gear of the timer cam, causing the block of program cams (6) to move one
step forward. The second multiplying factor is thus obtained.
[0043] The timer cam (26) is provided with a spring (55) that tends to displace the same
towards a fixed rest position defined by a spigot (56) located on the selector lever
(25). The catch (40) of the anti-return ratchet (27) prevents the timer cam from moving
back whenever it moves one step forward.
[0044] A ratchet (46) helps the ring gear (5) in the block of program cams so that with
the assistance of a spring (47), the block of program cams is accurately in place
for a step to be advanced, manually or automatically.
[0045] Whenever one or more steps are advanced in the block of program cams (6), the end
(48) of the positioning ratchet (46) pushes a surface (49) of the anti-return ratchet
(27), causing it to swing about an axis (50), and carrying the end (51) of its elastic
arm (36) to the position relative to the abutment (37) shown in figure 6, the cogs
(32) of the timer cam hence being released from the holding action of the catch (40)
in the ratchet (27). Shortly after this, the actuating pawl profile (52) will, with
the assistance of a spigot (53) integral with the support (38), cause the catch (4)
in the actuating pawl to rise, moving away from the ring gear (54) driving the timer
cam, both actions allowing the timer cam to be free to return, by action of the spring
(55) to its stand-by position as defined by the abutment (56).
[0046] We feel that the device has now been sufficiently described for any expert in the
art to have grasped the full scope of the invention and the advantages it offers.
[0047] The materials, shape, size and layout of the elements may be altered provided that
this entails no modification of the essential features of the invention.
[0048] The terms used to describe the invention herein should be taken to have a broad rather
than a restrictive meaning.
1.- Step-by-step timer switch activation system for program control devices, of the sort
comprising a block of fast cams (1), permanently turning at a steady speed, and a
block of program cams (6) which are activated step by step by a pawl (3) which acts
upon a ring gear (5) integral with the block of cams and which an eccentric cam (2)
provides with a steady to-and-fro motion, the system having means to temporarily prevent
the forward catch from reaching the ring gear in the block of program cams, the said
timing means comprising two parts that can act together or on their own, one of them
yielding stop intervals of length equal to the period of rotation of the block of
fast cams and/or fractions thereof, and the other yielding one or more multiples of
at least one of the foregoing and in which the multiplication system comprises a timer
element or wheel and a detent or like element, both located between the two blocks
of cams, and wherein with both the timer wheel being in turn disposed coaxially with
both blocks of cams it is provided with elastic means that cause it to return to a
fixed point, which is where the pre-set time starts, whenever the block of program
cams moves one step forward once the pre-set time has begun, and means preventing
it from returning during the said pre-set time and wherein for resetting the element
holding the timing wheel to zero they are removed and held inactive until after resetting
to zero as aforesaid, whereupon resetting elements again place them in a position
to act, and wherein the detent is taken from its active position at the end of the
pre-set time by means of a surface that is integral with the timer wheel, essentially
characterised in that the same is also provided with a swinging detent (9) that can
take up two positions, in one such position standing in the way of the free end (7)
of the actuating pawl (3) and in the other staying away from the same, the positions
of the detent (9) being defined with the assistance of a likewise swinging clearance
lever (13), with three working positions, so that at the two end positions the detent
(9) is out of the way of the actuating pawl (3), and stands in its way when the former
is in the middle position, the clearance lever (13) having two probes (15) and (16)
related to the same number of internal cam profiles (17) and (18), both having three
levels, one located in the block of program cams (6) and the other in the block of
fast cams (1), activation of the timer wheel (26), which when at rest does in no case
stand in the way of the actuating pawl (3), coming about upon angular displacement
thereof caused by the respective displacement of the holding ratchet (27) to engage
the relevant ring gear (32) in the timer wheel (26), whenever the selector lever (25)
so allows, its probe (28) following an internal profile in a second selector cam (29)
having three levels, in the block of program cams (6), such selector lever (25) having
a surface (31) which, when the said lever (25) is at any of the three cam levels,
prevents displacement of the holding ratchet (27) towards the relevant ring gear (32)
in the timer wheel (26), allowing this when at either of the other two levels.
2.- Step-by-step timer switch activation system for program control devices, as in claim
1, characterised in that the detent (9) has an arm whose free end (8) is able to engage
the free end (47) of the actuating catch (3) and a spigot (11) which is related to
a profile (12) located on the free end of the clearance lever (13).
3.- Step-by-step timer switch activation system for program control devices, as in previous
claims, characterised in that the free end (7) of the actuating catch (3) has a recess
for coupling with the detent.
4.- Step-by-step timer switch activation system for program control devices, as in previous
claims, characterised in that elastic means (10) permanently urge the actuating catch
(3) and the detent (9) towards the position of engagement with each other.
5.- Step-by-step timer switch activation system for program control devices, as in previous
claims, characterised in that the clearance lever (13) has its free end shaped as
a cam profile (12) and has elastic means holding it in engagement with the cam profiles
in the block of fast cams (1) and/or block of program cams (6).
6.- Step-by-step timer switch activation system for program control devices, as in claim
1, characterised in that the timer wheel (26) has an external ring gear (39) with
spaces between cogs of two depths, the internal diameter of the shallower spaces being
somewhat larger than the external diameter of the ring gear integral with the block
of program cams and the internal diameter of the deeper spaces being equal to the
internal diameter of the latter's spaces, the said timer wheel also having an internal
holding ring gear (32) which has a ramp-like surface (41) at its threshold, at an
angle to the radius, and finally also having a surface (43) which acts when the pre-set
time is over upon the salient (44) on the selector lever (25), pushing the same.
7.- Step-by-step timer switch activation system for program control devices, as in claims
1 and 6, characterised in that the anti-return ratchet (27) arranged as a sort of
swinging lever and located on the side of the timer wheel (26) has a holding catch
(40) on one of the swinging arms, working with the internal ring gear in the timer
wheel (26), having an inclined surface (41) in the timer wheel (26), with a probe
or abutment likewise located on its free end and able to work with a supporting surface
(31) in the selector lever (25), with an elastic arm (36) which forms a single part
with the ratchet and which has two working positions in one of which its free end
abuts against a salient (37) in the supporting plate (38) upon which the ratchet is
mounted to swing, holding the catch (4) away from the relevant ring gear (32), whereas
in the other it rests upon a surface at a right or like angle to the foregoing, whereupon
it may swing freely, the natural tendency of the elastic arm being to move toward
the position at which it abuts, also having a probe (35) located on the elastic arm
(36) close to its free end, upon which it acts, displacing the same to release the
end of the arm from its abutting position, a salient (34) located on the periphery
of a cylindrical portion, concentric with the spin axis and integral with the eccentric
cam (2), while the second swinging arm has a surface (49) which works with the positioning
ratchet (46) in the block of program cams (6) or else one or two cogs connecting directly
with the ring gear (5) in the said block of cams, moreover applying elastic means
(33) to the said arm, tending to displace the ratchet towards its position of engagement
with the timer wheel (26).
8.- Step-by-step timer switch activation system for program control devices, as in claims
1, 6 and 7, characterised in that the selector lever (25) is provided with a probe
(28) which follows an internal selector cam (29), having three levels, in the block
of program cams (6), a supporting surface (31) which works with the anti-return ratchet
(27) probe that, when the lever at the cam level of greater radius, prevents the anti-return
ratchet from engaging the timer wheel, a lock that, when the lever (25) is at the
cam level of smaller radius, prevents the actuating pawl (3) from engaging the ring
gear that is integral with the block of program cams (6), an abutment (56) which works
with a surface (43) in the timer wheel (26) and displaces the lever, when the pre-set
time is over, beyond the position of the cam level of smaller radius, removing the
lock from its active position, and elastic means tending to hold the lever with its
probe against the cam profile.
9.- Step-by-step timer switch activation system for program control devices, as in claims
1, 6, 7 and 8, characterised in that the actuation pawl (3) has, between its housing
for the eccentric cam (2) and the drive catch (4), a hollow area (52) whose internal
profile works with a spigot (53) on the plate (38) supporting mechanisms, so that
when the pawl moves back, it draws the catch away from the ring gears upon which it
is to act, again drawing near as soon as it begins to move forward.
10.- Step-by-step timer switch activation system for program control devices, as in previous
claims, characterised in that the block of program cams (6) has two internal cam profiles
(21) and (22), each having three levels, adjacent to one another, and a single ring
gear (5) integral with the same, the cogs thereof all being flush with each other,
and in that the block of fast cams (1) also has an internal cam profile (18) with
three levels.
11.- Step-by-step timer switch activation system for program control devices, as in previous
claims, characterised in that the activation and timer elements as a whole, saving
the two blocks of cams, are mounted to form a stable assembly, upon a plastic supporting
plate (38) provided with shafts and guides and housings therefor, and the necessary
supports and points of attachment for the appropriate springs, such plate being located
between the blocks of fast (1) and program (6) cams.