Push button assembly

April 25, 1961

2,981,816

ί.

R. T. COZART

PUSH BUTTON ASSEMBLY

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ATTORNEY?

April 25, 1961

2,981,816

R. T. COZART

PUSH BUTTON ASSEMBLY

Filed July 25, 1957 2 Sheets-Sheet 2

FIG . 3.

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F1C. 4 .

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INVENTOR

ROBERT T. COZART

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ATTORNEYS

United States Patent Office

2,981,816

Patented Apr. 25, 1961

2,981,816

PUSH BUTTON ASSEMBLY

Robert T. Cozart, 107-09 S. Willow Ave., Tampa 6, Fla.

Filed July 25,1957, Ser. No. 674,203

Claims. (Cl. 200—159)

This invention relates to a push button assembly and 15 more particularly to an assembly of unique button units.

Heretofore, the common push button assemblies have comprised a plurality of push buttons that are individually mounted and guided. Such push button assemblies, while operating adequately if properly made, are unduly costly ²θ to manufacture. The high cost of such assemblies results directly from the complexity of the push button units which normally include the buttons proper, actuating rods, guide tracks, return springs, and perhaps additional operating linkages and anti-friction bearings as well. Moreover, the number of such parts which must be included in any given assembly is directly proportional to the number of push buttons required, and it is readily apparent that when a large number of push buttons is necessary, the cost of manufacturing and assembling the component parts can become quite high.

To ensure proper and relatively trouble free operation, the push button assemblies of the prior art must be manufactured with relatively precise tolerances, and this, of course, further increases the cost and increases the possibility of improper operation and breakdown. Where prior push button assemblies are subjected to vigorous use, as in vending machine operation, the problem of maintenance of the assemblies often becomes substantial. It is necessary to spend an inordinate amount of time to tear down, repair, and re-assemble the push button units, even though the defective part may be nothing more than a simple coil return spring. Even simple repairs are costly because of the time expended by skilled personnel in going to and from the job. Moreover, because of the type of construction, the push button assemblies in existence prior to the present invention are easily affected by weather conditions. Corrosion and deterioration of the parts of such assemblies is not infrequent, particularly when the assemblies are used in relatively unprotected locations where they may be subjected to dust and rain or when they are used in high humidity climates.

Push button assemblies are often used to actuate mechanical linkages directly but frequently are employed to open and close switches in electrical circuits. Prior to the present invention, it has often been necessary to mount an individual switch on each push button unit or to mount the switches separately from the push button assembly. The inherent disadvantages of such constructions are self-evident,

Accordingly, it is a principal object of the present invention to provide an improved push button assembly of unique construction which overcomes the failings and deficiencies of the prior comparable assemblies'

A further object of the invention is to provide a push ₆₅button assembly that is much less susceptible to deterioration by weather conditions, including dust, rain, and high humidity.

Another object of the invention is to provide a push button assembly of extreme simplicity, both in its physical configuration and in its mode of operation.

An additional Object' of the invention iS' to provide a push button assembly which reduces the number of manufacturing steps and the cost of manufacture to a minimum.

Yet another object of the invention is to provide a push button assembly comprising unique push button units which require neither guides, tracks, complex operating linkages, nor individual return springs.

A still further object of the invention is to provide push button units which will operate properly notwithstanding the fact that the push buttons may be tilted as they are depressed rather than depressed rectilinearly.

Still another object of the invention is to provide a push button assembly which incorporates a switching network as an integral part.

Yet another object of the invention is to provide improved push buttons of unique construction.

An additional object of the invention is to provide push buttons which permit the display of indicia and which permit the indicia display to be readily changed.

These and other objects of the invention and the manner in which such objects are accomplished will become more readily apparent upon consideration of the following detailed description of an exemplary embodiment of the invention taken in conjunction with the accompanying drawings illustrating such embodiment and wherein:

Figure 1 is an exploded view of a typical section of a push button assembly constructed in accordance with the principles of the invention;

Figure 2 is a transverse sectional view of the assembly of the invention taken along the line 2—2 of Figure- 5 35 and illustrating the manner in which it is operated;

Figure 3 is a similar longitudinal sectional view of the assembly of the invention taken along line 3—3 of Figure 5;

Figure 4 is a perspective view of a typical section of an 35 assembly constructed in accordance with the teachings of the invention as seen from the bottom; and

Figure 5 is a plan view of the assembly.

Briefly stated, the push button assembly of the invention comprises a base plate, a layer of resilient material ⁴θ on one side of the base plate, and a plurality of push buttons on the layer side remote from the base plate. The push buttons pass through openings in a face plate which Overlies lateral projections on the push buttons, so as to prevent movement of the push buttons away from 45 the base plate beyond predetermined limits. The push buttons are provided with operating shafts which extend through aligned openings in the resilient layer and the base plate to engage the devices to be operated, which in the form described are constituted by electrical switches 5θ assembled on the side of the base plate opposite to the resilient layer. When the push buttons are depressed,, the resilient material beneath the push buttons is compressed, returning to its original shape when the push buttons are released. The construction is such that the 55 push buttons may be tilted when they are depressed and still operate the switches. The construction of the individual push buttons is such as to allow the insertion and removal of indicia sheets identifying the controlled devices.

5Q Referring to the drawings, reference numeral 10 designates a base plate which may be formed of a suitable sheet material, such as an aluminum alloy, and which may have a channel cross section as shown in Figure 1 to increase its structural rigidity. A sheet of resilient material forms a layer 12 on one side of the base plate; This layer is preferably formed of a material which retains its resiliency indefinitely, and in a practical form of the invention a sheet of foam rubber about one-half inch in thickness has been found suitable.

Push buttons 14 are located on the side of layer 12 ^u remote from the base plate 10, and in the form of the invention illustrated, two rows of push buttons are em2,981,816 ployed. Each push button may comprise a supporting plate 16 formed, for example, from a sheet of stainless steel, the sheet having upwardly converging side flanges 18. A block of transparent material 20 is detachably mounted on the supporting plate 16 between the side flanges 18 and has upwardly converging side walls which complement and engage the side flanges 18. Each push button has lateral projections 22 which may form an integral part of the supporting plate 16. An operating shaft 24 extends from the supporting plate below the block 20 and may be formed by soldering or otherwise attaching a metal pin to the supporting plate at the proper location.

The base plate 10 is provided with a plurality of holes 26 therethrough which are aligned with holes 28 in the resilient layer 12. These holes accommodate the operating shafts 24 of the push buttons, but the diameter of the holes is made substantially greater than the diameter of the shafts so that the shafts may have substantial lateral motion within the holes.

In the form shown, a face plate 30, which may be formed of the same metal stock as the base plate 10, lies upon the surface of the resilient layer 12 remote from the base plate 10. The face plate 30 is provided with a plurality of openings 32 through which the push buttons protrude as shown in Figures 2 and 3. The lateral projections 22 on the push buttons abut the under surface of the face plate as shown in Figure 3, and these projections in cooperation with the adjacent portions of the face plate constitute means to limit the movement of the push buttons away from the base plate 10. As shown in Figure 3, the face plate may be fixed to the base plate as by a plurality of screws 34. If the screws are not threaded into the face plate, but merely pass through apertures therein, the face plate may be depressed toward the base plate, but the resiliency of the layer 12 is sufficient to maintain the face plate in its proper position, and any slight motion of the face plate towards the base plate is of no consequence.

While the push button assembly of the invention may be utilized to actuate purely mechanical linkages, in the preferred form of the invention, the push button assembly is made integral with a switching system operated by the push buttons. As shown in Figure 4, the switches 36 may be of the leaf spring type having insulators 38 which support leaf springs 40, at the ends of which are mounted contacts 42. Stationary contacts 44 are supported on metal arms 46 secured to insulating strips 48. Insulators 38 and insulating strips 48 may be individually secured to the base plate in any suitable manner, as by riveting. Alternatively, the switch network may be manufactured as a separate assembly which may then be united with the base plate.

The switches illustrated are of the single pole double throw type, the moving contact 42 engaging one stationary contact 44 in a first position and another stationary Contact 44 in a second position. The push button operating shafts 24 engage one side of the leaf springs 4® and close the normally open contacts when the push buttons are depressed, compressing the resilient material in their path. The normally closed contacts are closed when the push buttons are released and returned to their normal positions by expansion of the resilient material. An insulating sleeve 52 may be placed over the operating shaft 24 of each push button, or the push buttons may be otherwise insulated from the switches, as by placing insulating strips on the leaf springs. Lead wires 50 from the switch contacts may be connected to a suitable wiring harness (not shown), the end of which may include a plug type connector, thereby making the push button and switch assembly completely independent of other mechanisms. For vending machines and similar uses it is preferred to wire the push buttons in a series supply circuit through the normally closed contacts (as shown in Figure 4) so that when any button is depressed to close its normally open contacts and complete a vending circuit, the supply circuit to the succeeding buttons is broken.

An important feature of the invention is the ability of the push buttons to operate the switches 36 even though the push buttons may be tilted when depressed, as when a corner of the push button is engaged by the fingers of the user, rather than the center of the push button. As shown in Figure 3, when a push button is tilted as it is depressed, the operating shaft 24 is likewise tilted, but the operating tolerance of the switches is made such that the switches will operate notwithstanding the tilt of the operating shafts. The lateral dimensions of the push buttons are correlated with the gapping of the switch contacts so that sufficient longitudinal movement of the operating shafts is obtained to ensure proper operation of the switches regardless of the point of the surface of the push buttons at which the depressing force is applied. The area of the leaf springs 40 beneath the operating shafts 24 must, of course, be great enough to accommodate the lateral movement of the operating shafts.

It is thus apparent that the push button units of the invention do not require guides or tracks to operate properly. The apertures in the face plate 30 are made large enough to allow adequate clearance for the tilting movement of the push buttons without binding but at the same time maintain the push buttons in their proper positions on the assembly.

The push button assembly of the invention is very simple to manufacture. It is only necessary to place the resilient layer 12 on the base plate, the push buttons 14 on the resilient layer, and to secure the face plate 30 over the push buttons. The holes in the various members are preferably preformed by conventional techniques. While the resilient layer 12 may be cemented or otherwise attached to the plates 10 and 30, this is unnecessary, since the resilient layer will be held in place through the cooperation of the plates 10 and 30 and the screws 34. The resilient layer is preferably slightly compressed between the plates 10 and 30.

The use of a single resilient layer as shown eliminates the need for individual return springs, reducing the manufacturing costs accordingly. The resilient layer operates properly without maintenance and is substantially insensitive to climatic conditions.

An indicia sheet may be placed under each of the transparent push button blocks 20 so as to identify the devices controlled by the push buttons. For example, when the push button assembly is utilized to dispense cigarettes, a picture of a pack of a particular brand of cigarettes may be placed under each of the respective push button blocks to identify the brands dispensed by operation of the push buttons. To change the indicia sheets once the push buttons are in place under the face plate 30, the blocks 20 may be pried up by a screwdriver or other tool, against the natural resiliency of the side flanges 18, and then forced back into place when the proper indicia sheets have been inserted.

While a preferred embodiment of the invention has been shown and described, it is evident that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims. For example, the construction of the individual push buttons could be varied by forming each of the push buttons entirely of plastic in a single molding operation. A decorative cover could be placed over the face plate. Accordingly, the foregoing embodiment of the invention is to be taken as illustrative rather than restrictive of the invention, and those modifications which come within the meaning and range of equivalency of the claims are included therein.