US2981808A - Interval timer - Google Patents

Description

April 25, 1961 K. w. KLEIN INTERVAL TIMER Filed July 8, 1958 Pie.

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lhvehi'or- Kelrh W. Klein His ATforhej pro-3 z,9s1,ss

INTERVAL rut/ran Keith W. Klein, Hophinton, Mass, assignor to Genera! Electric Company, a corporation ct New Yo it Filed July lass, so. 747,253

6 Claims. (ill. 2@ti--38) This invention relates to timers and more particularly to timing mechanism for automatic household appliances.

it is an object of the invention to provide an improved timer with which to eilfect simultaneous operation of a switch and a signal and which includes an interlocking arrangement of components that prevents actuation of the signal until the switch is actuated.

A further object of the invention is the provision of an improved timer mechanism which holds contacts of a switch closed for manually preselected length of time and at the termination of the selected time automatically opens the switch contacts and actuates a signal simultaneously with the opening of the switch.

Another object is the provision of an additional manually selectable off position in which the switch contacts are open and the signal is shut off.

A further object is the provision of still another manually selectable manual or on-hold position of the mechanism in which the switch contacts are closed and the signal is shut off until manually changed.

Still another object is to provide a timer mechanism of the character described in which timing mechanism and signal are actuated by the same constantly operating motor.

A further object is the provision in mechanism of the character described of means for rendering the signal responsive to the motor and following completion of "ranually preselected time period only.

Gther objects will be in part obvious and are in part pointed out in the following description of an illustrative embodiment of the invention made with reference to the accompanying drawing in which:

l is a perspective view partly in phantom of timer, signal and switch mechanism and showing a switch held in the closed or on position with a vibrator held in a restrained or oit" position by a timer cam;

Fig. 2 is a vi w similar to Fig. 1 showing the switch open and the vibrator in an on position free of restraint; and

Fig. 3 is a perspective view similar to Figs. 1 and 2 showing the switch in the on-hold position unresponsive to the timer motor and the vibrator in the off position.

Referring to the drawing, the timer-responsive switch and signal mechanism there disclosed includes a base or frame plate ltl on which. the components of the mechanism are mounted. A normally open switch 11 is suitably secured to the plate iii and includes a pair of contact arms 12 and 13 which, as shown in Fig. 3, normally separate and hold open a pair of contact points 14 and 15.

The switch 11 may be selected for a variety of uses. Merely by way of illustration, the switch may control the current to a rotisserie oven, an attic fan or other household or kitchen appliance the operation of which is intended to be shut off automatically at the end of a presclectable time.

As shown in the drawing, a switch actuator 16 is slidably supported in a slot 57 in the plate and preferably States aten 2,981,808 Patented Apr. 25, 1961 further supported by other suitable bearing surfaces and members (not shown) on and carried by the plate.

The switch actuator 16 shown in the drawing is formed of rigid non-conductive sheet material and is adapted to press the switch arm 12 toward the arm 13 to close contacts 14- and 15 as shown in Figs. 1 and 3 responsive to a cam 17 which is secured to a shaft 18 that is rotatably journalled in the plate 10. The switch may be opened entirely by the bias of switch blade 12 toward cam 17 when the timer is turned to the off position.

The actuator 16 is resiliently pressed against the cam 17 by switch blade 12 and by pressure foot 19 of a bell crank lever 20 which is pivotally secured at 21 to the plate 10 and yieldably biased clockwise by a tension spring 22 suitably anchored to the plate and secured to the lever 20.

The cam 17 and cam shaft 18 are rotated by a timer generally designated 23, through a train of gears which are generally designated 24.

In the illustrated embodiment, the timer 23 includes a synchronous electric motor 25 which is suitably secured to the base plate 10. The motor 25 preferably is continually energized and rotates a drive pinion 26 at constant speed.

The drive from the pinion 26 to the cam shaft '18 is through the gear train 24 which in the embodiment illustrated as shown in Fig. 1 includes gear 27 and pinion 28; gear 29 and pinion 3d; and gear 31 and pinion 32, all of which are suitably journalled on the base plate 10.

The drive from the pinion 32 to the cam shaft 18 is ti rough gear 33 which, as shown in the drawing, may be die cast or otherwise formed as an integral part of me timer switch cam 17,

Preferably, the gear 31 and pinion 32 are journalled in the end of a lever 34 the other end of which is pivotally mounted on the axis of the pinion 30 so that the pinion 32 may be swung out of engagement with the gear 33 without disengaging the pinion 30 and the gear 31. A spring 35 yieldably biases the lever 34 counterclockwise so that the pinion 32 normally is in driving engagement with the gear 33. Thus the cam 17 and cam gear 33 may be manually rotated counterclockwise to any selected position and the gear 33 merely earns the pinion 32 temporarily out of mesh without straining the gear train 24 or the motor 25.

Similarly, in order to provide for clockwise rotation of the cam 17 manually without excessive strain on the gear train 24 and the motor 25, the drive from the gear 31 to the pinion 32 preferably is through a conventional friction slip clutch connection (not shown).

When the timer is set so that the switch actuator 16 is riding on the smooth surface portion 36 of the cam 17, the switch contacts 14, 15 are closed and the cam is set to a suitable time interval which is measured by the time that is required for the motor 25 to rotate the cam 17 counterclockwise to the open switch or off position shown in Fig. 2. In the position there shown, the pressure foot 19 of the spring tensioned bell crank lever 20 and the bias of switch blade 12 forces the actuator 16 inwardly into a recess 37 in the cam 17, thereby relieving the switch arm 12 from the restraint of the actuator 16 and opening the contacts 14, 15. i

In accordance with the present invention, a signal is activated immediately upon separation of the switch contacts 14 and 15. Preferably, the signal is created directly by the continually operated timer motor 25 and is responsive to the movement of the actuator 16 and the lever 29 to the open switch position shown in Fig. 2.

In the embodiment of the invention illustrated in the drawing, a signal vibrator blade 38 is secured at 39 to the base plate 10. The blade 38 includes a portion 40 which is disposed adjacent the pole pieces 41 of the motor 25 so that the blade 38 is audibly vibrated by the motor.

As shown in Fig. 1, an inclined cam portion 42 on the bell crank 20 engages and dampens the vibration of the blade 38 and effectively silences audible vibration when the switch contacts 14 and 15 are open and the bell crank 20 is cammed counterclockwise by engagement of the cam follower edge portion 44 of the bell crank 20 with a signal cam 43 that is secured on the timer shaft 18. The cam 43 includes a recess 45 into which, as shown in Fig. 2, the follower 44 moves and thereby releases the vibrator blade 38 from the restraint of the cam edge 42 so as to create an audible signal when the switch contacts 14 and 15 open. a r

The actuator 16 holds the cam 42 of bell crank 20 under the vibrator 38 until actuator 16 moves from surface 53 of the cam to surface 37, at which point actuator 16 is moved against surface 37 by the combined forces of pressure foot 19 and switch blade 12. f

Preferably the edges 46 and 47 of the cam recess 45 are inclined so as to readily and easily engage and cam the follower portion 44 of the lever 20 outwardly onto the outer surface 48 of the cam 43 when the shaft 18 is manually rotated to press the cam 42 against the blade 38 as shown in Fig. 1 and thereby silence the audible signal as well as reset the timer cam 17 and close the switch contacts 14 and 15.

Preferably means are provided for releasing the blade 38 quickly from the restraint of the cam 42 and for avoiding a gradual lessening of the dampening action of the cam 42 on the blade 38 such as would be effected were the follower edge 44 to travel into the cam recess 45 on the cam surface 47.

. Accordingly, the bell crank 20 is restrained in the counterclockwise or signal off position by the switch actuator 16 and the cam 17 through the pressure foot 19 until the follower edge 44 of the crank 44 is aligned with the deepest portion of the signal cam recess 45. Thereupon the switch actuator 16 is snapped into the recess 37 in the cam 17 and the follower edge 44 of the lever 20 into the recess 45 by the spring 22 so as to abruptly open the switch contacts 14 and 15 and release the signal blade 38 from the restraint of the cam 42 as shown in Fig. 2. Preferably the cam restraint on the actuator 16 immedi ately prior to the opening of the switch contacts is provided by a cam lever or extension 50 which is pivoted at 51 to the cam 17 and resiliently biased clockwise by a spring 52 to the position against the cam hub 17a shown in Fig. 1. Duter edge 53 of the lever 50 provides a smooth continuation of the cam surface 36 for restraining the cam follower portion 16a of the slidable journalled actuator 16. However, when the cam edge 53 is rotated past the follower 16a, the follower snaps inwardly and may pivot the lever 50 counterclockwise sufficiently so that edge 54 offers no resistance to abrupt inward movement of the actuator and fast no-arc opening of the switch contacts.

Preferably the surface 54 of lever 50 is undercut suf- I ficiently to allow cam follower 16a to move from cam surface 36 to 37 without interference with surface 54 or movement of lever 50. When the follower 16a engages cam surface 37 the friction pinion 32 operates in a section 33a (Fig. 3) of the cam gear 33 from which the teeth are removed so that the cam 17 is not further advanced by the motor 25 and must be reset manually.

The pivoted cam extension 50 also provides for ready manually clockwise reset rotation of the cam 17, theactuator 16 engaging and swinging the extension counterclockwise and riding readily out on the gentle slope of the recess 37 to the cam surface 36 when the cam 17 is manually rotated clockwise and reset. Concurrently the bell crank follower edge 44 rides out the signal cam edge 47 onto the cam edge 48 which holds the lever 20 in silencing engagement with the signal vibrator 38 as shown in Fig. 1. r

Manual rotation of the cam 17 to align the actuator 16 with a cam recess 55 locates the actuator in the open switch .position and forces the vibrator silencer 42 outwardly onto the signal cam edge 48 and into silencing engagement with the vibrator blade 38.

Further rotation of the cam 17 to align the actuator with cam recess 56 holds the switch contacts closed and the vibrator blade 38 engaged and silenced by the cam 42 In both of the last two cam recesses 55 and 56 as well as in the recess 37 the friction pinion 32 is operating' in the portion 33a of the gear 33 from which the teeth are removed so that the timer motor 25 does not move the cam 17 from these positions. It is only when the cam 17 is set so that the actuator 16 engages a selected time point on the cam surfaces 36 or 53 that the timer drives the cam for the selected time period to the open switch and signal sounding position.

The upper cam -17 may carry the load of the spring 22 and controls the position of the silencer crank 20 as well as the switch actuator 16 whenever the cam follower portion 161: of the actuator 16 is on the cam surface 36 or 53 and also whenever the follower 16a is in the cam recess 37 and the lower follower 44 is centered inthe recess 45 of the lower cam 43.

However, when the cam shaft 18 is manually rotated in either direction from this last position, either the cam surface 46 or 47 on the lower cam 43 picks up the load of the spring 22 and relieves the actuator 16 and the cam 17 of pressure from the pressure foot portion 19 of the lever 20. Consequently, the cam 17 is relieved of the heavy pressure which is entailed in stretching and loading the spring 22 when the lever 20 is moved counterclockwise to the signal silencing position shown in Fig. 3. The cam 17 assumes the spring load only after the spring is loaded and stretched and the actuator 16 is either on the cam surface 36 or in either of the recesses 55 or 56.

If desired, the cam surface 36 may be contoured so as to be relieved of the load of the spring 22 by the surface 48 of the lower cam 43 in which case the load preferably is transferred to the cam extension surface 53 when the follower 44 leaves the outer surface 48 of the lower cam 43.

From the foregoing it will be apparent that the present invention provides an improved timer, signal and switch mechanism the operation of which is integrated so that opening of a switch is automatically accompanied by sounding of a signal. The signal control lever 20 is dependent upon operation of the switch control actuator 16. The signal vibrator 38 is released by the lever 20 and sounds only when the actuator 16 is moved to the open switch position shown in Fig. 2.

Furthermore, the vibrator signal is energized whenever the timer is operating and is sounded whenever the switch is opened by operation of the timer motor.

Where the description of the illustrated embodiment of the invention refers to an open or a closed switch and to an active or an inactive signal, it will be understood that the opposite switch or signal conditions or both may be substituted in the same or different combinations as required by a particular appliance or other device which is to be controlled by an automatic timer switch and signal mechanism involving the present invention.

While the invention has been described with reference to a particular embodiment, it is to be understood that the embodiment is illustrative in character and that changes are contemplated within the scope of the appended claims without departing from the present invention.

I claim:

1. In a timer mechanism, a switch, a rotatable cam having a generally circular portion and a recessed portion, a timer motor for rotating said cam, a cam shaft for setting the angular position of the cam, a member interposed between the cam and said switch, said member being biased into slidable contact with said cam for operation by said circular portion and said recessed portion of said cam, a signal means operated by the timer motor, and a restraining lever for the signal means resiliently urged into contact with said member, said lever being responsive to operation of said member responsive to said cam.

2. In a timer mechanism, a switch, a cam shaft carrying a cam, a continually operated timer motor for driving said cam shaft to a terminal point, the angular position of the cam shaft being manually adjustable relative to said terminal point, a reciprocally journalled cam follower interposed between the cam and said switch, one portion of said reciprocal follower engaging the cam for operation thereby and another portion engaging the switch for operation thereof, said follower being movable between terminal positions, a signal means operatively connected permanently to the timer motor, a member operatively restraining the signal means and means including a lever spring biased into contact with said follower automatically operable to relieve said signal of said restraint when the follower moves to a terminal position.

3. In a control and signal mechanism for an electrical switch, a timer mechanism comprising a rotatable cam, a continually operated synchronous motor for rotating said cam, a shaft for manually setting said cam, a switch controlled by said cam through a follower, a vibrator signal blade arranged in the magnetic circuit of the synchronous motor, and a control member for the sounder blade arranged to engage the sounder blade when the follower is in one position and to release the sounder blade when the follower is in another position, said control member being restrained by said follower in the first of said positions and free of said follower in the second of said positions.

4. In a timer mechanism, a switch including an operating element biased in one direction to open position, a freely reciprocal actuator member engaging said operating element and a cam shaft and cam having a generally circular raised portion and a recessed portion, said cam being movable through successive positions in which the generally circular raised portion thereof causes the actuator to move said element against'its bias into the closed position of said switch, said cam being further movable to a position in which the biased element presses said actuator into said recess and opens said switch, an alternating current synchronous motor for operating said cam shaft, a vibrator signal in the magnetic field of said motor, a resiliently operated control member arranged to engage and release said blade, said actuator restraining said control member in engagement with said blade when the actuator holds said element in the closed switch position, and said actuator releasing said control member so as to release said blade when said actuator moves into said recess and said switch element moves to the open position of the switch.

5. In a timer mechanism, a switch including an operating element biased in one direction to an open position, a cam shaft, a first cam on said shaft having a generally circular portion and a recessed portion, a switch actuator engaged and biased by said element into engagement with said cam, said actuator being held by the generally circular raised portion thereof in a position to hold said element in closed position and movable into said recess when said element is biased to open position, an alternating current synchronous motor for operating said cam shaft, a vibrator signal blade arranged in the magnetic field of said motor, a resiliently biased control member operable to engage and release said blade, and a second cam on said cam shaft for moving said control member to engage said blade.

6. The timer mechanism recited in claim 5 and wherein said actuator restrains said control member in engagement with said blade and out of engagement with said second cam when said actuator engages the first cam and holds the switch element in closed position.

References Cited in the file of this patent UNITED STATES PATENTS 1,986,499 Browning Jan. 1, 1935 2,274,635 Rhodes Mar. 3, 1942 2,421,986 Bohman June 10, 1947 2,444,748 Parissi July 6, 1948 2,512,775 Parissi June 10, 1950 2,525,463 Spooner et a1. Oct. 10, 1950 2,752,592 Gallagher et al. June 26, 1956 2,768,332 Protzmann et a1. Oct. 23, 1956

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