US 3309487 A
Abstract available in
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Description (OCR text may contain errors)
March 14, 1967 H. F. FISHER PUSH BUTTON ACTUATOR T Fil ed Jan. 15, 1966 3,309,487 PUSH BUTTQN ACTUATOR Harold Francis Fisher, West Newton, Mass, assignor to Ark-Les Switch Corporation, Watertowri, Mass, a corporation'of Massachusetts Filed Jan. 13, 1966, Ser. No. 520,507
' Claims. (Cl. 200172) The present invention rel atesi'to push button switches, and more particularly to an improved switch button suitable for use in a multiple push button switch.
It is a principal'object of the invention to" provide an improved switch push button suitable for use in a multiple pushbutton switch, which comprises a unitary' molded mass of an electrically insulating material having the 're- .quired qualities of strength, toughness, and resiliency, swhich will perform all thewfunctions normally required of such push buttons including the spring frictioned retention of said button in each of its alternative raised and depressed positions.
It is a further object of; the invention to provide an improved push 'button of this general description consisting of a unitary mass of. a molded plastic material having desired qualities of elec trical non-conductivity, durability, toughness, and resiliency, which has formed integrally therewith resilientlyformed darts which can be yieldably pushed aside to permit. the insertion and'assembly of the push button throughthe switch cover, .ar 1d which .will then act to lock'the push button in its assembled position. V I 1 Further objects, features and advantages of the inventign will appear from the following detailed description of the. embodiments shown taken in conjunction-with the accompanying drawing in which: i FIG. 1 is a perspective view of a multiple push button switch embodying therein the several features of the invention;
FIG. 2 is a perspective view of "one form of' my improved switch button, the cover aperture for the switch button being indicated in dotted lines;
FIG. 3 is a section taken on a line 33"0.f FIG. 2;
FIG. 4 is a, partialsection taken on a line 4-4 of FIG. 1; f
FIG. 5 is a=-view similar to FIG. 4, the push button being shown in its fully depressed position;
FIG. 6 is a detail plan section taken on a line 6-6 of FIG. 4;
FIGS. 7, 8 and 9 illustrate a modified form of push button in accordance with the invention, of which:
7 is a perspective view of the modified push button having darts for locking the push button in assembled position, the cover aperture :for the switch button being shown in dotted lines;
FIG. 8 a somewhat fragmentary view, partly in section, corresponding to FIG. 4, illustrating the modified push button in its assembled position in the switch; and
" .FIG. 9 is a detail sectional yiew taken on a line 9-9 r FIG. 8.
The improved push button which forms specifically the subject matter of the invention is particularly, but by no means exclusively, adapted for use in a switch of the general type which comprises a series of push buttons and a series of sliders underlying the push buttons by means of which the push buttons are rendered selectively opera- .tive to close associated switch contacts. A switch of this general type is illustrated in a United States Patent No. 2,652,470 dated Sept. 15, 1953, to H. W. Batcheller for Push Button. Each push button is supported in a guide- 'way to move between raised inoperative and depressed switch closing positions and consists generally of a shank having formed at its upper end a finger press surface and at its lower end a wedge shaped operating surface which extends transversely across the working edges of the several sliders. Longitudinal downward extensions of the push button at each end of the wedge shaped operating surface provide lateral support for the sliders and act also ice , as guide supports having sliding engagement with suitable guideways.
In the illustrated construction the switch assembly includes an elongated rectangular housing 10 of molded plastic and a cover 12. A series of trans-verse frames 13 are molded therein, attached respectively to the bottom and one side of the housing. Each said frame is formed with a rectaiigular cutout including a bottom. edge on which the sliders indicated at 14 are supported, and two side posts 16,18 having the facing edges thereof grooved to provide guideways 19 for the push buttons 20 hereinafter more fully to be described. The electrical connections controlled by the respective push buttons and sliders comprise a common connector 21 extending along one side of the bottom panel and a series of fixed terminals 22, one such terminal being mounted on the bottom panel of the housing 10 adjacent each of said frames and a series of cooperating switch arms 24 which extend transversely beneath the sliders in position to be pressed to an open position by engagement with an operating nub 26 on an associated slider 14.
The push button which forms more specifically the subject matter of the invention comprises a unitary mass of: an electrical non-conducting material, molded and shaped to provide a rectangular shank 30 having the upper end thereof formed as a finger press surface, andthe lower central portion thereof formed as a wedge shaped operating surface 34, which extends across the working edges of the several sliders 14. Four rectangularly shapedguide blocks or flanges 36 are provided extending downwardly from each corner of the shank. These guide blocks extend outwardly beyond the edges of the shank, acting as guides for engagement with the guideways 19. The inner facing edges of the guide blocks' 36provide side supports for the group of sliders 14, which are thus confined beneath the wedge shaped workingsurface of the push button. Between the two guide blocks 36 at each edge of the shank there is provided also a downwardly extending resilient friction guide arm 38 which is formed integrally with the1shank, projects downwardly beyond the guide b1ocks"36,' and is then hooked outwardly =and up for yielding frictional engagement with the f'back wall of the guideway 19. In the preferred construction illustrated, bump 40 formed midway of the length of the back wall of each said guideway causes the friction guide arm 38 to act as a detent to assist in holding the push button yieldably in each of its alternative retracted and operating positions. The push buttons 20 are additionally guided and supported by the sides of the slots in the cover 12 through which the push buttons are projected one such slot being indicated in FIG. 2 at 41 in dotted lines. The ends of slots 41 are extended sufficiently to receive the flanges 52, and are formed also with narrow cutouts 42 of sufficient depth to receive the friction guide arms 38 when compressed, allowing the push buttons to be assembled through the cover 12. The arms'38 are then permitted to spring outwardly thus locking the push buttons 20 in position.
The unitary push button above described in connection with FIGS. 1 to 6 inclusive of the drawings has the advantage that it is made up in one piece of a suitable plastic material which may, for example, be a molded polysulfone plastic material having the necessary qualities of strength, toughness, and resiliency for the performance of the substantial number of functions required of it.
single molded part results also in substantial savings in the cost of manufacture, and in a more satisfactory record of continuous long-lived performance. The arrangement of the depending guide blocks and intervening hook shaped resilient friction guide members provides a useful and effective structure for guiding and for yieldably supporting the push button in each of its raised and depressed operative positions.
FIGS. 7, 8, and 9 illustrate a modification of the invention consisting of a push button generally similar to the push button 20 above described but having an oversized head, and barbs arranged to permit the assembly of the push button through the cover. These barbs Will then be biased outwardly and will perform the specific function, otherwise required of the friction guide arms 38, of locking the push button in the assembled position. The modified push button, generally indicated at 44 in FIG. 7, comprises a shank 46 provided with an oversized head 48, and at its lower end with a transverse wedge shaped operating surface 50. The push button 44 is similar to the push button 20 described in connection with FIGS. 1 to 6 inclusive, in that there is provided at each corner of the shank a downwardly extending guide block 52, having outer edges in sliding engagement with guideways 19 and inwardly facing edges which provide guide supports for the group of sliders 14. Between the guide blocks 52 at each edge of the shank 46 there is provided, also, a downwardly extending, outwardly and upwardly hooked resilient friction guide arm 54 formed integrally with the shank in the same manner as the friction guide arms 38 of the push button 20 above described. In this modification of the invention also the slot 56 in the housing cover 58 is made long enough and is further notched at 59 to allow the guide blocks 52 and friction guide arms 54 to be forced downwardly through the slot 56 during assembly. Removal of the push button by the same route is, however, prevented by four darts 60, one of which is integrally attached to the face of each guide block 52. At their upper ends the darts 60 are sprung outwardly so that as the push button is pushed downwardly through its slot 56 to the assembled position the darts are first pressed inwardly into correspondingly notched portions 62 of the slots 56 indicated in dotted lines in FIG. 7, and are then released and moved outwardly into locking position with relation to the under side of the cover 58 as shown in FIG. 9.
While there are herein disclosed and described presently preferred embodiments of the invention, it will nevertheless be understood that the same is susceptible of modifications and changes by those skilled in the art, and
therefore, it is intended that the scope of the invention be limited only by the proper scope to be afforded the appended claims.
1. A push button for use in a push button switch having spaced guideways with friction surfaces along which said push button is adapted to be moved between raised and depressed positions, which comprises a molded unitary mass of a plastic material having required qualities of electrical non-conductivity, durability, toughness, and resiliency having a substantially rectangular shank, formed at one end with a finger press end surface, and at the other end With a cammed operating surface, and with guide appendages integrally attached to said shank and disposed adjacent to opposite edge faces of said shank, including outwardly biased resilient friction guide members for yieldably guiding engagement with said spaced guide and friction surfaces for yieldably guiding and supporting said push button in each of said raised and depressed positions.
2. The push button as defined in claim 1 in which the unitary mass of said push button is composed of a molded polysulfone plastic material.
3. The push button defined in claim 1, in which said appendaged friction guide members comprise arms forming resilient downward extensions of said shank from adjacent said edge faces of said shank, each said arm hooked outwardly and upwardly .for resilient guiding engagement with said spaced guide and friction surfaces.
4. The push button as defined in claim 1 in which said guide appendages comprise guide blocks extending downwardly from and outwardly from said edge faces to provide guide surfaces beyond the edge faces of the shank, and downwardly extending outwardly and upwardly hooked resilient friction guide arms formed integrally with the cammed end of said shank adjacent said edge faces of the shank and between adjacent guide blocks.
5. The push button as defined in claim 4 in which said block extensions have integrally formed with the front and rear faces thereof darts attached at their lower ends to said block extensions and formed at their upper ends as outwardly biased barbs.
References Cited by the Examiner UNITED STATES PATENTS 2,835,753 5/1958 Lewis 200 5 ROBERT K. SCHAEFER, Primary Examiner.
H. O. JONES, Assistant Examiner,