Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Generally speaking, the present invention pertains to a timing
mechanism having a power drive means rotating first and second cam means
and a double pole switch means opening and closing in response to a
rotation of the cam means comprising coupling means coupling the power
drive means to the cam means; first and second movable spring blades
disposed in substantially parallel relation and having lengths which are
substantially equal, first and second electrical contacts one each
carried on each of the blades respectively near distal ends thereof and
facing each other, a third spring blade fixedly disposed between the
first and second spring blades and in substantial parallel relation
therewith, the third spring blade having a length shorter than the
lengths of the first and second spring blades so as to provide a gap
between the sarne at their distal ends, and third and fourth electrical
contacts carried on opposed surfaces of the third spring blade in oper-
ational position with the first and second electrical contacts; and
first and second actuator arms pivotly mounted in ends thereof to be
pivoted in response to the cam means, a distal end of one of the actu-
ator arms entering the gap and engaging the first and second spring
blades to open the first and second electrical contacts from said third
and fnurth electrical contacts, a distal end of the other actuator arm
entering the gap and engaging one of the first and second spring blades
to open one of said first and second electrical contacts from one of the
third and fourth electrical contacts.
One of the cam means includes a sharp contour to a step with
one of the actuator arms engaging the cam means to quickly drop at the
sharp drop contour to the step. The timing mechanism also includes,
in this embodiment, an audible sound means having a spring biased
striker pivotly carried on the actuator arm and engaging the audible
sound means, whereby the striker drops with the actuator arm and con-
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tinues dropping after the arm engages the step to strike the audible
sound means.
In another embodiment of the invention there is provided a
short pulsing cycle within a complete program of the timing mechanism.
~n this embodiment one of the actuator arms serves to provide the short
pulsing cycle and there is a manual selector means serving as a means to
disengage the second actuator arm from its cam means to render the
pulsing cycle inoperative for a predetermined period of time.
The present invention pertains to a timing mechanism and more
lo particularly to a timing mechanism which provides a short pulsing cycle
within a timing program and an alarm system to signal the end of a
program and wherein a double pole switching means is also provided.
Timing mechanisms have for sometime been used to control the
functions of various appliances such as washers, dryers and microwave
ovens. Depending upon the application, such timing mechanisms need to
provide various programs. For example, in the case of a timing mecha-
nism for a microwave oven there is a need to provide a short pulsing
cycle operable within the overall program. Such a system usually requires
a double pole switching arrangement and in most cases there shculd also
be a means to remove the pulsing cycle frorn the system if desired. In
addition, there is also sometimes a need to provide an alarm means in
conjunction with the timing mechanism to signal the end of a program.
OBJECTS OR FEATURES OF THE INVENTION
Accordingly, it is a feature of the present invention to
provide a timing mechanism having a means to provide a double pole
switching arrangement. Another feature of the invention is to provide
such a timing mechanism wherein a double pole switching arrangement is
provided by three parallel spring blades, each having electrical con-
tacts in operational alignment with each other and wherein actuator arms
responsive to separate cam means selectively engage the spring blades.
Another feature of the invention is the provision of such a timing
mechanism wherein two outside movable spring blades
extend in length beyond a fixed middle third blade to
provide a gap into which the actuator arms enter to engage
the blades. Another feature of the invention is the
provision of such a timing mechanism wherein the distal
end of one of the actuator arms enters the gap and
engages the outside spring blades to open and close
electrical contacts from the middle blade and wherein the
distal end of the other actuator arm enters the gap and
engages one of the outside blades to open its contact
from the electrical contacts of the middle third blade.
Yet another feature of the invention is the
provision of such a timing mechanism wherein there is
provided an audible sound means with a means to engage
the sound means. Another feature of the invention is
the provision of such a timing mechanism having a cam
means which includes a sharp drop contour to a step and
wherein an actuator means engages the cam means to
quickly drop at the sharp contour to the step and wherein
a spring biased striker is pivotly carried on the actuator
so that it will continue to drop after the actuator
engages the step to strike the audible sound means.
Yet another feature of the invention is the
provision of such a timing mechanism having a short
pulsing cycle operable within the complete program of the
timing mechanism. Still another feature of the invention
is the provision of such a timing mechanism wherein the
programs are provided by two actuator arms engaging
separate cam means and wherein there is a manual selector
means permitting one of the arms to become disengaged
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from its cam means. These and other features of the
invention will be apparent from the following description
taken in combination with the accompanying drawings.
According to a broad aspect of the present
invention there is provided a timing mechanism comprising
switch means including first electrical contacts control-
ling a complete program of the timing mechanism, and
second electrical contacts controlling a pulsing cycle
within the complete program. A first actuator means
engages a first cam means and the first electrical
contacts to open and close the contacts. A second
actuator means engages a second cam means and the second
electrical contacts to open and close same. A selector
means is provided to disengage the second actuator
means from the second cam means to render the pulsing
cycle inoperative. Power drive means is provided for
driving the first and second cam means.
DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a top view of a timing mechanism
employing the features of the invention.
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FIGURE 2 is an end view of the timing mechanism of FIGURE 1
with portions thereof broken away.
FIGURE 3 is an exploded view of the cam means of the timing
mechanism and a coupling means which couples the cam means to the motor
drive means of the timing mechanism.
FIGURE 4 is a view taken along the line 4-4 of FIGURE 1.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, there is shown a timing mechanism
10 employing the features of the invention. The elements of the timing
mechanism are enclosed in a cup-shaped housing member 12 with a cover
plate 14 enclosing the open end of the housing. A cam 16 is fixedly
carried on a shaft 18 which is rotatably journalled in the base 12' of
cup-shaped member 12. A second cam 20 is rotatably journalled on shaft
22 which is fixedly carried in base member 12' of the cup-shaped hous-
ing. Both of the cams are coupled to a suitable motor drive means 24,
which is schematically shown in FIGURE 4, through coupling means 26.
Coupling means 26 includes a series of gears and pinions 28, 29, 31, 33,
34, 35, 36, 37 and 38 and a clutch means 30. As more particularly shown
in FIGURE 3, the gears and pinions include two pairs of cooperating non-
circular gears such as scroll gears 33, 35, and 36, 38. Such scroll
gears provide for a non-linear speed of rotation to cam 16 such that the
rotation of the cam can be varied as desired. As shown cam 20 is
located upstream toward the motor from the scroll gears such that it is
driven at a constant speed.
A pair of actuator arms 40 and 42 are pivotly carried on a
post 44, the post being carried by housing member 12. Actuator arm 42
has a cam follower 46 which engages cam 20 while actuator arm 40 has a
cam follower 48 that engages cam 16. Thus, actuator arm 40 pivots in
accordance with the program of cam 16 while actuator arm 42 pivots in
accordance with cam 20. Both the actuator arms are spring biased toward
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their respective cam through a spring 45 which includes a pair of fingers
45' and 45" engaging actuator arms 42 and 40 respectively.
Referring to FIGURE 1, in accordance with one aspect of the
invention, a double pole switching means is provided with the combination
of actuator arms 40 and 42 and double pole switching means 50. Double
pole switching means 50 includes outer movable spring contact blades 52
and 54 and middle fixed contact blade 58 all of which are mounted in
terminal block 56. The terminal block is formed as part of housing
member 12. As shown, the blades are in substantial parallel relation to
each other and the outer blades 52 and 54 have lengths which are substan-
tially equal and longer than the fixed middle blade 58 to provide a gap
60 at the distal ends of the outer blades and at the end of the middle
blade. The outer blades 52 and 54 carry electrical contacts 52' and 54'
near their distal ends in line with and facing each other. The middle
contact blade 58 carries electrical contacts 58' and 58" at its distal
end in line with and facing the other two contacts. Each of the actua-
tor arms include V-shaped extensions 40' and 42' extending from the
distal ends of the actuator arms. When the actuator arms are pivoted in
accordance with their respective cams, the V-shaped extensions will
enter gap 60 to engage the outer spring contact blades 52 and 54 to
selectively open and close the electrical contacts. ~hen being used in
a microwave oven, for example, when the oven is working, all the contacts
will be closed. During this time the oven can be intermittently turned
off and on through cam 20 operating actuator arm 42 to open contacts 54'
and 58". At the end of the complete cycle cam 16 causes actuator arm 40
to drop to disengage contacts 52' and 58' to completely open all the
contacts.
Referring to FIGURES 2 and 3 a manual selector means 62 permits
actuator arm 42 to be disengaged from the system. Manual selector means
62 includes a handle 64 which is carried by the actuator arm 42 and
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extends through an elongated slot 66 so that the handle may be moved
lengthwise in the slot. Although not shown in the interest of simplicity
it should be understood that means would be provided to hold the handle
in a desired position.
Cam 16 has a very sharp drop contour 68 such that actuator arm
40 very quickly falls, the fall being terminated by step 16' of the
cam. The sharp drop contour is provided by a spring pawl 70 carried on
cam 16. The spring pawl is pivotly carried at one end by post 72 which
is carried on the cam and the pawl is slideably carried by its inner
surface 70' by being sprung over post 74 which is also carried by the
cam 16. The spring pawl has a lug 76 that has a very sharp edge 76'
to provide the sharp contour 68. The lug 76 pivots between a tab 80 and
rim 82 which extends around the periphery of the cam except for the
space provided by the step 16'. As viewed in FIGURE 1, when cam 16
rotates in a clockwise fashion cam follower 48 approaches the lug 76 and
then quickly drops when it reaches the straight edge 76'. When the cam
is manually reset by rotating cam 16 in a counter-clockwise direction
lug 76 will pivot a sufficient amount to expose the tapered edge 16" of
step 16' to permit the follower 48 to become disengaged from the lug.
Upon follower ~8 being relieved from the lug, the lug will return to its
original position due to the action of the spring pawl.
Referring to FIGURE 1, 2 and 3, in accordance with another
aspect of the invention there is provided an alarm to indicate the end
of a program cycle of the timing mechanism. Such alarm is provided by
an audible sound means 90 which includes a bell 92 that is carried on
the cover 14 and a striker 94. Striker 94 includes an L-shaped arm 96
pivotly carried on post 98 which extends through and is carried by
actuator arm 40. The L-shaped striker engages the bell. lhe striker is
spring biased at its one end through a coil 100 which is carried on a
post 102 extending from the striker and which extends into a channel 104
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that is carried by the actuator arm 40. Stop means 41 stops the drop of
the actuator arm. In the present embodiment, stop means 41 includes
step 16' of cam 16. ~hen actuator arm 40 drops at the end of a cycle at
the straight edge 76' and quickly stops at step 16' of cam 16 striker 96
continues to drop to engage or strike the bell 92 to indicate the end of
the cycle. ~hen the striker engages the bell 92 the pivoting of the
striker causes coil 102 to compress to then disengage the striker from
the bell.
This is a division of Canadian patent application
serial number 335,237 filed September 10, 1979 ^~Ith the
same title.
