Multi-contact push-button switch having plural prestressed contact members designed to provide plural circuit simultaneous switching inputs

• US 3,996,429 A
• Filed: 04/18/1975
• Issued: 12/07/1976
• Est. Priority Date: 04/18/1975
• Status: Expired due to Term

• Current Assignee: Northern Electric PLC (Berkshire Hathaway Incorporated)
• Original Assignee: Northern Electric PLC (Berkshire Hathaway Incorporated)
• Inventors: Chu, Pak-Jong, Reedyk, Cornelis Wilfred
• Primary Examiner(s): Scott, James R.
• Application Number:
  US05/569,359
• Time in Patent Office: 599 Days
• Field of Search: 200/1 R, 200/5 R, 200/5 A, 200/67 D, 200/67 DA, 200/67 DB, 200/159 R, 200/159 A, 200/159 B, 200/160, 200/241, 200/242, 200/243, 200/275, 200/340
• US Class Current: 200/5.00A
• CPC Class Codes: H01H 13/48 using buckling of disc springs
• CPC Class Codes: H01H 13/66 the operating member having only two positions
• CPC Class Codes: H01H 2203/054 for redundancy, e.g. several contact pairs in parallel

Abstract

A push-button switch has a spring contact plate and a circuit board in superposed position. The spring contact plate has one or more switch positions, each switch position comprising a prestressed domed portion surrounded by a common flat sheet portion. The spring contacts of each prestressed dome portion selectively engage peripheral contact areas on the circuit board followed by the central contact portion engaging subsequently with a further fixed central contact area on the circuit board. Accordingly, plural inputs of electronic logic circuits may be preselected prior to simultaneous activation upon subsequent closure of the central contacts at a given switch position. Release of the push button enables the domed portion to snap back to the stable position.

Claims

1. A multiple pushbutton switch comprising:

a flat spring plate having a plurality of integral switch positions thereon;

each switch position comprising a prestressed domed portion extending upwardly from said flat spring plate and completely surrounded by a flat portion of said flat spring plate, said flat portion circumferentially constraining said domed portion, said domed portion including a center portion and a plurality of radial webs connecting said center portion and said portion of said flat spring plate surrounding the domed portion and integral therewith, each radial web having an upwardly bent portion at its junction with said portion of said flat spring plate, said webs radially constrained by said flat portion of said spring plate;

a central contact on said center portion;

a plurality of cantilevered spring contact members extending from said center portion, a contact member between each pair of radial webs and extending a radial distance less than said radial webs;

each spring contact member extending radially outward from said center portion and downwardly therefrom and including a contact area at a radially outwards end thereof;

a circuit member positioned below and spaced from said flat spring plate and including contact areas on said circuit member beneath said spring contacts and a further contact area on said circuit member beneath each central contact;

a plurality of pushbuttons mounted above said flat spring plate, a button over each domed portion to apply a downward force on the related center portion each said domed portion, on application of said downward force, arranged to snap downward towards said circuit member and to bend each of said webs adjacent to and radially inward of said upwardly bent portion to produce a return force on said domed portion;

said contact areas on said spring contact members at each switch position extending below the related central contact, to make contact with said contact areas on said circuit board beneath said spring contacts before said central contact makes contact with said further contact area on said circuit board, on application of said downward force on said center portion.

2. A push button switch as claimed in claim 1, including a cover member extending over said spring contact plate and a plurality of apertures in said cover, an aperture for each push-button, and interengaging formations on said cover and each of said buttons to retain said push-buttons in position.

3. A push button switch as claimed in claim 2, for a binary coded signal system, each of said contact areas having a predetermined contact configuration to produce a predetermined binary code on depression of a related push-button.