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

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.