US3367193A - Timing switch - Google Patents

Description

L. ROSE TIMING SWITCH Feb. 6, 1968 5 Sheets-Sheet 1 Filed Oct. 23, 1965 726/ Zfs 7% INVENTOR. LEONARD ROSE jam 1% A.

ATTORNEY Feb. 6, 1968 L. ROSE 3,367,193

. TIMING SWITCH Filed Oct 23, 1965 5 Sheets-Sheet 2 INVENTOR. LEONARD ROSE fimw/ a;

ATTOR EY Feb. 6, 1968 L. ROSE 3,367,193 TIMING SWITCH I Filed Oct. 23, 1965 3 Sheets-Sheet 5 LEONARD ROSE ATTORNEY United States Patent 3,367,193 THVIING SWITCH Leonard Rose, Wantagh, N.Y., assignor to Consolidated Airborne Systems, Inc, New Hyde Park, N.Y. Filed Oct. 23, 1965, Ser. No. 502,941 Claims. (Cl. 74--3.5)

ABSTRACT OF THE DISCLOSURE Precision timing device employing a plurality of individually adjustable cams on a common motor-driven shaft. A selected cam triggers a switch controlling linkage.

This invention relates to switches in general and more particularly to a timing switch having a plurality of individually selectable time intervals of different predetermined durations.

While the present invention has utility in many different fields, the description will be directed particularly to the use of a timing switch in a microwave oven. In that particular application, it is necessary to provide a simple and easily operated switch that has a number of different preset time intervals which the user may select in order to meet various cooking requirements.

A typical use for a microwave oven is in connection with refrigerated vending machines. The customer purchases an item from the vending machine and then cooks it himself. It is essential that the instructions to the customer be simple. Typically, the instructions may read: To cook this food item, (a) open the oven door; (b) insert merchandise; (c) close the oven door; and (at) press button No. 5. In order for the automatic vending installation to be practical, the pressing of the button must turn on the oven and also initiate an accurate, reliable timing mechanism. Because a variety of items of different nature are likely to be vended from a single machine. a range of cooking times must be provided. Further, since the cooking cycle is so short in a microwave oven, being measured in seconds, the timing mechanism must be reasonably accurate. It is also important, in order for the vending operation to be commercially feasible, that the switch be compact, relatively low in cost, and capable of a long maintenance-free life. As will be evident from the ensuing description, the timing switch of this invention satisfies all these requirements.

The timer of this invention allows the presetting of six different time intervals and then permits selection of a contact closing time when one of six buttons is engaged. After the interval passes, the timer automatically and instantaneously resets itself whereby it is ready for another time selection.

This device is extremely useful where a number of different fixed intervals are to be repeated. The timer is characterized by lightweight and compact and rugged construction, and is capable of operation under the most adverse conditions such as a greasy atmosphere.

The timer consists of a synchronous speed motor which is mechanically coupled to a cam shaft when any button is engaged. Six cams are pre-arranged on this shaft, the angular position of each cam representing a unique time interval. Any interval from five seconds to three minutes can be set into the timer by angular adjustment of the cam. This is simply and quickly done by a drive mechanism on the cam. The mechanism is self-locking so that while the cam is easily positioned through a screw drive slot accessible in the front of the timer, the action of the cam against the latching bar will not cause the cam to move.

The pushing in of a button accomplishes the following functions:

(1) It couples the cam shaft to the motor to start the cams rotating;

(2) It closes a set of contacts in an enclosed snap action switch; and

(3) It selects the cam which represents the desired time interval.

When the time elapses, the cam releases the engaged arm, which in turn opens the switch contacts and declutches the cam shaft from the motor. A torque spring returns the cam shaft to its starting position, resetting the timer and allowing another timer cycle to be selected.

Accordingly, it is an object of the present invention to provide a low cost, maintenance-free timing switch hav ing a selectable plurality of different time durations.

Another object is to provide an accurate timing switch of the aforementioned type.

A further object is to provide a timing switch wherein the time intervals may be readily and accurately set and/ or changed by authorized personnel.

Yet another object is to provide a timing switch of a size suitable for installation in a relatively small size microwave oven.

An additional object is to provide adjustable self-locking timing earns.

These and other features, objects and advantages of the invention will, in part, be pointed out with particularity and will, in part, become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawing, which forms an integral part thereof.

In the various figures of the drawing like reference characters designate like parts.-

In the drawing:

FIG. 1 is a front elevational view of the timing switch comprising the present invention;

FIG. 2 is a bottom plan view of the present invention;

FIG. 3 is an end elevational view as seen from the lefthand side of FIG. 1;

FIG. 4 is a detailed plan view of several components of the present invention;

FIG. 5 is a fragmentary transverse elevational view, in section, illustrating the relationship of the cams used therein;

FIG. 6 is a fragmentary bottom plan view of the motorized drive section;

FIG. 7 is a fragmentary sectional detail view illustrating means to mount a typical combination cam and gear;

FIGS. 8, 9 and 10 sequentially illustrate in transverse elevational views the position of various components at different times of a typical timing cycle;

FIG. 11 is a perspective view of a stop member used with this invention; and

FIG. 12 is a sectional elevational view taken along line 1212 of FIG. 11.

Referring now to FIGS. 1, 2 and 3 of the drawing, it will be seen that switch 20 includes a chassis comprised of front and rear plates 22 and 24 and end plates 26 and 28 secured to inwardly turned flanges of the front and rear plates. A mounting bracket 30 is secured to end plate 26 and serves to support a synchronous timing motor 32. A one-third r.p.m. synchronous motor has been found to be satisfactory. Motor shaft 34 extends through the mounting bracket and supports a driving clutch plate 36 that is biased into an operating position by means of a compression spring 38.

Transverse cam shaft 40, having a square cross sectional central portion and cylindrical ends, is rotatably journaled in the chassis end plates in opposition to the motor shaft;

Shaft 40 rigidly supports a driven clutch plate 42 proximate the driving clutch plate 36. Mounted on the cam shaft intermediate the end walls of the chassis are, in the embodiment illustrated, six timing gears 44a'to 44f in- Patented Feb. 6, 1968 clusive. By way of example, the gears may be fabricated from nylon and include an integral lobe 46a to 46f, respectively, extending radially from the periphery thereof. In the embodiment illustrated, the gear is a lefthanded face worm gear having 39 teeth. It is to be understood, of course, that this is by way of illustration only and without intending to be limiting.

Referring now particularly to FIG. 7, a typical gear is shown mounted on hub member 48. Each gear, of course, has its own individual hub. The gear is free to rotate angularly but is prevented from axial movement relative to the'hub by means of a step 50 formed in the hub and arranged to bear against the transverse gear web and a retaining ring 52 secured to the hub. Mating worm pinions 54a to 54f are rotatably secured to, and retained within, an extension portion 56 on each of the hub members. The

advantage of the face worm gear and pinion set is that it is self-locking after adjustment-Each pinion is provided with a slotted end that faces the front of the housing, so that it is available for adjustment through cutout 22a in the chassis front plate. The combination gear and cam assemblies are keyed to the shaft by means of the square shaft configuration and square bore provided in each hub member. Thus, a finite relation among the cams may be established.

At the end of the cam shaft opposite to the clutch assembly there is provided a stop member 8 (FIG. 11 and FIG. 12) arranged for rotation with the cam shaft. The stop member is provided with two spaced parallel legs 60a-and 60b, each'having square-shaped coaxial bores 62 permitting the stop member to be keyed to the cam shaftnFurther, leg 60a is provided with a tab portion 64 arranged to abut a resiliently convered post 66 secured to and extending inwardly from end plate 28. Stop member 58 limits the angular movement of the cam shaft to slightly less than 360. As will be described hereinafter, when the motor is running and the clutch plates are engaged, the stop member turns with the shaft. When the time cycle is completed and the clutch plates disengaged, it is desired to bring the stop member, the cams and the cam shaft back to its original starting position. Accordingly, a coiled clock-type spring 68 is mounted on the outside of plate 28. The inner end of the spring is secured to the lefthand end of the transverse cam shaft 40, and the opposite end of the spring is secured to the outward extension of post 66. The spring is wound up as the cam shaft rotates during the timing interval and unwinds to return the components to the starting position as determined by the stop member 58 engaging post 66.

Externally positioned pushbuttons 70a to 70 are each secured to one end of slide bars 72a to 72f, respectively, which are journaled in front and rear chassis plates 22 and 24. Each slide bar is a substantially flat member having stepped portion 74. One end of compression spring 76 is seated against the stepped portion and the opposite end of the spring abuts the inner surface of plate 24. Thus means. are provided for returning the selected pushbutton to its original outward position after the respective time interval has passed. Each slide bar is also provided with a first camming follower 78 integral with its upper edge, a sloping second camming follower 80 integral with its lower edge, and a third U-shaped camming follower 82 pivotally mounted on a pin 83 disposed in the body portion of the slide bar. Follower 82 is defined by an upper leg 84a positioned above the slide bar and a lower leg 84b positioned below the slide bar. Torsion spring 85 is disposed about pin 83 and extends between the upper edge of slide bar 72 and the lower leg 84b of the third cam follower. v

A clutch bar 86 (FIG. 4)- is a substantially flat plate, having six notches defined by a sloped camming wall 90a to 90p and walls 90a to 91) disposed in a plane parallel to the slide bar. Each notch corresponds respectively to a pushbutton, to a slide bar and to a cam/ gear assembly. The clutclf bar is mounted in the end plates of the housing 1 is complete. The opposite end of the clutch bar is bent upwardly in a plane substantially at right angles to the main portion of the bar and terminates in a yoke portion 94. Bushing 96, which is secured to the transverse cam shaft, has an annular groove 98 arrangedto receive the yoke. Therefore, displacement of the clutch bar by the pushbutton and slide bar causes axial displacementof'the cam shaft and engagement of the two clutch plates.

Latching bar 100 is pivotally journaled along onelongitudinal edge on pins 102 in the end plates 26 and 28 of the chassis. The latching bar lies in a plane parallel to the clutch bar and directly below the slide bars.

When a pushbutton is depressed, its associated follower overrides the free end of the latching bar which is proivded with a lip portion 104 extendingalong the longitudinal edge thereof opposite to the pivoting edge. Follower 80, because of its angularly-disposed contacting surface, tends to pivot the latching bar when it is moved thereover and also looks step 81 against lip 104.,A single, snap action switch 106 is mounted on plate 28 such that its contact button 108 faces upwardly and is in normal engagement with latching bar 100. Pivoting of the latching bar causes depression of the contact button and energization of the utilization device.

MODE OF OPERATION Assuming that the product to be cooked requires 15 seconds, the user would depress button No. 2. In so doing camming follower 78 would engage the angularly disposed edge of the associated notch in the clutch bar. The inward movement of the pushbutton and slide bar will displace the clutch bar to the right, causing yoke member 94 to shift the driven clutch face 42 into engagement with the driving clutch plate 36 of the motor. It should be noted, of course, that it is only when the motor is running and the clutch plates are in engagement, that the transverse shaft will be rotated thereby. The depression of the particular pushbutton will also cause the second follower surface to engage the latching bar. Thus a single pushbutton motion will simultaneously energize the switch and actuate the cam shaft through the motor.

Concurrently with the depression. of the switch, the

fluence of the motor. It should be pointed out now that, theangular location of the cam lobe is determined by adjustment of the gear through the pinion. Knowing the rotational speed of the motor, it is a simple step to angularly position the cam lobe 46 by rotating the slotted pinion 54 such that the time it takes the lobe to travel from its starting point to engagement with third follower leg 84 is equal to the desired time interval. When the lobe engages third follower leg 84a, the follower 82 is pivoted against the force of torsion spring 85. The pivoting action causes leg 84b to bear against depressed lip 104 of latching bar such that follower 80 is thereby released. Spring 76 returns the pushbutton to its outer position. and spring 92 returns the clutch bar 86 to its original position. With the return of the latching bar, the clutch faces are disengaged and spring 68 returns the transverse shaft to its original starting position. The apparatusis now available for a second cycle.

FIG. 9 illustrates one particular application of the present invention. Closing of the switch contacts completes the circuit between the motor 32, the utilization.

also initiates the timing cycle. Since each pushbutton has its own adjustable cam, the timing cycle may be very accurately terminated.

The apparatus just described is com-pact, low in cost and sufiiciently accurate to meet the requirements of a microwave oven, for example. A single operation starts both the timer and the oven so that instructions for the use of the device may be given in the very simplest of terms. The apparatus may be operated for any one of a number of predetermined time intervals so that many cooking requirements will be satisfied. In addition, means are provided permitting authorized personnel to readily and accurately set or change the various time intervals available.

Having thus disclosed the best embodiment of the invention presently contemplated, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. In combination with a switch, selectable time interval switch actuation means comprising:

(a) a plurality of pushbuttons each related to a given predetermined time interval;

(b) interposer means for mechanically placing the switch means in an actuated condition;

(c) a latching means connected to each of said pushbuttons, said latching means being normally positioned in spaced relationship to said interposer means whereby when a given said pushbutton is depressed, its associated said latching means engages said interposer means; and

(d) means for automatically deactuating said switch and returning said depressed pushbutton to its initial position upon the completion of the time interval.

2. An actuating mechanism for a utilization device having a plurality of operating cycles of different time duration, said actuating mechanism comprising:

(a) a chassis;

(b) a plurality of externally manipulatable slide bars movably mounted in said chassis said slide bars having first and second camming surfaces;

(0) a cam shaft having a first clutch face coupled to said cam shaft having end portions rotatably journaled in said chassis, the axis of said shaft being transverse the direction of movement of said slide bars;

(d) a plurality of cams mounted on said shaft for rotation therewith, each of said cams having a lobe in operative association with one of said slide bars;

(e) a drive motor and a drive motor shaft driven thereby mounted on said chassis;

(f) a second clutch face carried by said drive motor shaft;

(g) a clutch bar slidably mounted in said chassis for movement in a direction parallel to the axis of said cam shaft, said clutch bar being in engagement with said cam shaft and positioned for engagement by the said slide bar first camming surface of a selected slide bar whereby said clutch bar is displaced and said first and second clutch faces are engaged;

(h) a latching bar pivotally mounted in said chassis, said latching bar being positioned for engagement by the said second camming surface of a selected said slide bar for displacement about an axis parallel to said cam shaft by the movement of any one of said slide bars, said latching bar being returned to its original position by the rotation and contact of said cam lobe with a third camming surface on said slide bar; and

(i) utilization device control means positioned proximate said latching bar and arranged for actuation thereby responsive to the movement thereof.

3. The apparatus in accordance with claim 2 including adjustment means to vary the angular location of the cam lobes with respect to each other.

4. The apparatus in accordance with claim 2 including a plurality of hub members mounted on said cam shaft for rotation therewith, a gear member integral with each of said cams, said gear members being axially restrained in said respective hub member and arranged for angular displacement with respect thereto, and a pinion rotatably mounted in each of said hub members and in meshing engagement with a respective said gear, adjustment means being included on each pinion for angular displacement thereof whereby each of said gears, said cams, and said cam lobes maybe angularly displaced.

5. The apparatus in accordance with claim 2 wherein said third camming surface is pivotally mounted on and resiliently biased with respect to said slide bar.

6. The apparatus in accordance with claim 4 wherein said hub members are keyed to said cam shaft.

7. The apparatus in accordance with claim 4 wherein the central portion of said cam shaft has a noncircular cross section and said hub member each have a mating aperture of similar shape whereby said hub members are keyed to said cam shaft.

8. The apparatus in accordance with claim 2 wherein said clutch bar includes a body portion having a plurality of notches along one edge thereof, each of said notches having a sloping wall in the path of said respective first camming means whereby movement of said slide bars in a direction transverse the length of said clutch bar will provide a camming action to thereby displace said clutch bar body portion, said clutch bar further including a leg member integrally joined at one end to said body portion, the opposite end of said leg member terminating in a yoke arranged to engage and displace said cam shaft upon movement of one of said slide bars.

9. The apparatus in accordance with claim 2 wherein said latching bar includes a lip portion extending along one edge thereof whereby movement of one of said slide bars in a direction transverse the length of said latching bar causes a portion of said second camming means to hook onto said lip whereby said slide bar is retained in the position to which it has been moved.

10. The apparatus in accordance with claim 2 including stop means integrally mounted on said cam shaft for rotation therewith, said chassis including a post member arranged to limit the rotation of said stop member at either end of the angular travel thereof, there being further included spring means arranged to return said cam shaft to its original position after completion of a time interval during which said cam shaft has rotated from one extreme position to another.

References Cited UNITED STATES PATENTS 3,015,003 12/1961 Simmons 74--3.5 X

MILTON KAUFMAN, Primary Examiner.

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