US2997884A - Switch actuating timer - Google Patents

Description

Aug. 29, 1961 c. M. J. JAUCH 2,997,884

SWITCH ACTUATING TIMER Filed Feb. 24, 1959 2 Sheets-Sheet 1 IN V EN TOR.

1961 c. M. J. JAUCH 2,997,884

SWITCH ACTUAT'ING TIMER Filed Feb. 24, 1959 2 Sheets-Sheet 2 INVENTOR.

. Z/hmey U i -ed States Patent? F 2,997,884 SWITCH ACTUATING TIMER Christian M. .l. .Iauch, Winsted, Conn., assignor to General Time Corporation, New York, N .Y., a corporation of Delaware Filed Feb. 24, 1959, Ser. No. 795,118 Claims. (Cl. 74-352) ing the invention can effectively control a refrigerator.

defrosting cycle lasting but a few minutes and whic occurs only once or 'twice a day.

It is also an object of the invention to provide a timer: as described above which utilizes a single, small cam tooperate a switch at an exactly timed moment for an exactly timed interval, even though the switch operating;

interval is only a small fractional part of a total timing cycle which is of substantial duration.

It is another object to provide a reliable timer having the above characteristics which is quite compact, and which is inexpensive to manufacture.

. Other objects and advantages of the invention will become apparent upon reading the following detailed de-' scription and upon reference to the drawings, in which: FIGURE 1 is an elevation of a timer embodying the present invention with portions broken away to expose the'underlying parts;

FIG. 2 is a section taken approximately along the line 22 of FIG. 1; and

: FIGS. 3, 4, 5 and 6 are fragmentary stop-motion views.

illustrating an operating sequence of the timer shown in FIG. 1.

. While the invention will be described in connection With a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Turning now to FIGS. 1 and 2, there is shown a switch actuating timer 15 embodying the invention and arranged to operate an electric switch 16. The timer includes a frame 17 which carries a housing 18, preferably formed of dielectric material, that encloses the components of the switch 16.

The switch includes a resilient, movable contact arm 21 that is fixed at one end to a terminal 22 mounted in the housing 18 and which supports a pair of opposed contacts 23, 24. The movable contact arm 21 cooperates with a pair of fixed contacts 25, 26 carried by terminals 27, 28, respectively, mounted in the switch housing.

The switch 16 is preferably of a snap-acting type and thus the contacts 23, 24 are mounted on a carrier 31 which is pivoted at 32 between a set of flange plates 33 formed integrally with the end of the resilient contact arm 21. A tensioned spring 34 is connected between the outer end of the contact arm 21 and the outer portion of the carrier 31, so that the arm 21 and the carrier. 31 form a resiliently overcentered toggle assembly. In this way, when the pivot point 32 of the carrier 31 is lowered through the longitudinal centerline of the spring 34, the carrier overcenters and snaps upwardly. When the pivot point 32 is raised through the centerline of the spring 34, the carrier 31 reverses and snaps downwardly.

2,997,884 Patented Aug. 29,

For actuating the switch 16, the movable contact arm 21 is provided with an operator 35 and is mounted so that the inherent resilience in the arm 21 biases the operator against the periphery of a rotatable cam 36. The

operator 35 takes the form of a pin which is secured between the flanges 33 formed on the end of the contact arm 31. The cam 36 is secured to a sleeve 37 which is freely rotatable on a shaft 38, and the cam is provided with an operating portion in the form of a drop-off notch 40.

As the cam 36 is rotated to bring the drop-01f notch 40 adjacent the switch operator 35, the resilience of the arm 21 swings the operator 35 into the notch so as to lower the contact carrier pivot point 32 through the centerline of the spring 34, thus causing the switch to snap into its alternate position. The notch 40 is provided with a cam edge 41 so that continued rotation of the cam 36will liftthe operator 35 and raise the carrier pivot point 32 through the centerline of the spring 34, thereby restoring the contacts to their original position.

In accordance with the present invention, the cam 36 is driven through a lost-motion connection at a predetermined speed, and an overdrive member is provided which engages the cam and drives it at a higher speed for a short interval within each cam cycle, during which interval the switch 16 is operated. In the illustrated embodiment, the lost-motion connection takes the form of a drive member 45 journaled coaxially with the cam 36 and having a surface 46 which engages an abutment lug 47 on the cam. Preferably, the drive member 45 is uniformly rotated by a: timing motor 48 mounted on the frame, 17 and having,

' an output shaft 49 extending from a speed reducing gear output shaft 49 and positioned to engage the lug 47 when.

assembly 50. A pinion51 is secured to the shaft 49 and drivingly engages a gear 52 secured to enlarged portion 53. of shaft 38 which also carries the drive member. 45

(see FIG. 2). Energizing the motor 48 rotates the mem her-45 steadily in a clockwise direction, as seen in the drawings, and engagement of the surface 46 with the lug 47 rotates the cam 36 along with the drive member 45.

In the preferred form of the invention, the overdrive member comprises an arm secured to the timing motor the latter is swung adjacent the output shaft. The timing motor 48 rotates both the drive member 45 and the overdrive arm 60, and the pinion 51 and the gear 52 are proportioned so that the overdrive arm rotates at a speed which is a multiple of the speed of the drive member 45.

In the illustrated practical embodiment, the arm 68 makes six revolutions for every revolution of the drive member 45. The overdrive arm 60 and the drive member 45 are also phased so that the drop-off notch 40 passes the switch operator 35 during the interval in which the arm 60 en'- gages the lug 47 to propel the cam 36.

To more readily understand the operation of the timer 15, the function of its various components during a timing cycle will be briefly reviewed. During most of the timing cycle the switch operator 35 rests on the periphery of the cam 36 so as to hold the pivot point 32 of the contact carrier 31 above the center line of the spring 34.

The spring thus holds the contacts 24, 26 closed and the contacts 23, 25 open. The cam 36 is driven slowly by the drive member 45 whose surface 46 engages the lug 47 mounted on the cam. In the typical illustrated embodiment, the drive member 45 rotates at an even speed of one revolution every twelve hours, and thus the cam 36 against the lug 47 so as to drive the cam 36 at the higher speed at which the overdrivearm rotates. While the arm 60 is driving the cam, the lug 47 simply pulls away from the surface 46 of the more slowly moving drive. member 45.

During the interval at which the cam 36 is. moving at the relatively higher speed imparted to it by the arm 60, the notch 40 is swung beneath the switch operator 35 so. that the operator drops into the notch. This. causes the. contact carrier 31 to overcenter and to close contacts 23, 25 while opening contacts 24, 26 (see FIG. 4). Con.- tinued movement of the cam 36, still at its relatively higher speed, causes the cam surface 41 to lift the operator 35 onto the periphery of the cam 36 and to restore the switch 16 to its original position with the contacts 23, 25 open and the contacts 24, 26 closed (see FIG. 5).

When the overdrive arm 60 swings past the lug 47 (see FIG. 5), the cam 36 remains stationary until the surface 46 of the drive member 45 catches up with the lug 47 and the member resumes rotation ofthe. cam 36 through its timing cycle (see FIG. 6).

It will thus be seen that the switch-controlling cam 36 rotates quite slowly through the majority of its relatively long timing cycle and then moves more rapidly during the interval in which the switch 16 is actually operated. The length of the interval during which the switch remains operated depends upon the circumferential length of the notch 40 and, in the illustrated embodiment, the notch operates the switch for a period of two minutes in each 12-hour cycle.

Since the cam is moving relatively rapidly when the switch operator 35 is lowered and then raised, it will be appreciated that the times at which the operator 35 is manipulated can be controlled quite exactly. This is because a more rapidly moving cam repeats more reliably at exactly desired intervals than would a very slowly moving cam. Those skilled in the art will also appreciate that since the cam 36 moves very slowly except while operating the switch 16, the diameter of the cam 36 and thus the overall size of the timer 15 can be kept at a minimum. The two-speed cam of the timer 15 thus makes possible quite a compact timing assembly despite the relatively long timing cycle involved.

It will also be observed that the timer 15 is made up of components which are quite similar to the elements found in conventional cam-controlled switches and therefore it will be appreciated that these components can be quite economically manufactured and assembled using conventional tools and techniques. As a result, the timer 15 may be inexpensively produced.

I claim as my invention:

1. A mechanism actuating timer comprising, in com.- bination, a mechanism operator, a cam positioned adjacent said operator and being mounted for movement through a cycle, said cam having an operating portion effective to operate said operator for a period during said cycle, a timing motor, a lost-motion connection coupling said motor and said cam for driving the latter through its cycle at a predetermined speed, an overdrive member coupled to said motor so as to be driven through a cycle at a rate which is a multiple of said cam. speed,.

said cam and said overdrive member having parts engageable for a short interval during each cam cycle during which said member drives the cam out of driving:

relation with said lost-motion connection and at a higher speed, said cam and said member being phased so that said operating portion actuates said operator during said higher speed interval.

2. A mechanism actuating timer comprising, in combination, a mechanism operator, a cam journaled adjacent said operator and having an operating portion eitective to actuate said operator for a period during each revolution of the cam, a timing motor, a drive member and an overdrive member each being rotated by said motor, the speed of said overdrive member being a multiple of the speed of said drive member, said cam having an abutment portion engageable by said drive member so that the cam is driven through a timing cycle, said overdrive member being positioned and phased relative to said drive member so as to engage said abutment portion once during each timing cycle and thus drive said cam at a higher speed for a timed interval, said cam operating portion being positioned to actuate said operator during said interval.

3. A mechanism actuating timer comprising, in combination, a mechanism operator, a cam movably mounted adjacent said operator and having an operating portion effective to actuate said operator for a period during each cycle of the cam, a drive member and an overdrive member each being driven through repeating cycles, the speed of said overdrive member being a multiple of the speed of said drive member, said cam having an abutment portion engageable by said drive member so that the cam is driven thereby through a timing cycle, said overdrive member being positioned and phased relative to said drive member so as to engage said abutment portion once during each timing cycle and thus drive said cam at a higher speed for a timed interval, said cam operating portion being positioned to actuate said operator during said interval.

4. A mechanism actuating timer comprising, in combination, a mechanism operator, a cam journaled adjacent said operator and having an operating portion eflective to actuate said operator for a period during each revolution of the cam, a drive member journaled coaxially of said cam, said cam having an abutment lug engageable by said drive member, means for uniformly rotating said drive member and thus driving said cam,

an overdrive arm journaled adjacent said cam and being uniformly rotated at a speed which is a multiple of the speed of said member, said drive member and said arm being phased so that the arm engages said lug and rotates the cam at a higher speed during each cam revolution, said cam operating portion being positioned to actuate said operator when the cam is moving at said higher speed.

5. A mechanism actuating timer comprising, in combination, a mechanism operator, a cam journaled adjacent said operator and having an operating portion effective to actuate said operator for a period during each revolution of the cam, a timing motor, a drive member journaled coaxially of said cam, said cam having an abutment lug engageable by said drive member, means coupling said motor and said drive member so as to uniformly rotate said drive member and thus drive said cam, an overdrive arm journaled adjacent said cam and being coupled to said motor so as to be uniformly rotated at a speed which is a multiple of the speed of said member, said drive member and said arm being phased so that the arm engages said lug and rotates the cam at a higher speed during each cam revolution, said cam operating portion being positioned to actuate said operator when the cam is moving at said higher speed.

References Cited in the file of this patent UNITED STATES PATENTS 2,424,116 Puerner July 15, 1947

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