Deformable membrane keypad assembly for public telephones

Claim 1

In a telephone keypad assembly comprising a plurality of keypad pushbuttons, each of said pushbuttons including a cylindrical recess on an ainterior facing side, each of said pushbuttons including an annular surface positioned coaxially with said cylindrical recess, a housing unit with an openings region comprising a plurality of openings for osupport of individual ones of said keypad pushbuttons and including a sealing surface around a periphery of said openings region, and electrical contacts forming a part of a telephone electrical circuit in response to selective depression of one of said keypad pushbuttons, an improved sealing and circuit actuation membrane, comprising: an upper surface for mating with said interior facing side of said keypad pushbuttons and said sealing of said housing unit, and a lower surface; said upper surface defining a plurality of raised areas and including a peripheral edge portion for mating with said sealing surface of said housing unit; each of said raised areas defining a dome, a cylindrical collar disposed on top of said dome for mating with said annular surface of said pushbuttons, and a cylindrical alignment protrusion extending from said cylindrical collar for mating with said cylindrical recesses in said pushbuttons; said lower surface defining a plurality of well areas corresponding to said plurality of raised areas in said upper surface; each of said well areas including a contact actuator extending perpendicularly to said lower surface; each of said contact actuators having an electrically conductive material disposed at the distal end thereof for contacting said electrical contacts for completing said telephone electrical circuit when said pushbuttons are depressed; and said well areas and said raised areas forming biasing means for urging each of said raised areas away from said electrical contacts when said pushbuttons are released.