Tire air pressure sensor switch with temperature responsive bimetallic fixed contact assembly

Claim 1

A tire pressure sensor comprising: housing means; a diaphragm disposed in said housing means so as to sealingly divide said housing means into first and second chambers, said first and second chambers respectively communicating with the inside of the tire and the atmosphere; a compression spring disposed in said second chamber for urging said diaphragm toward said first chamber; an actuating rod disposed in said first chamber and connected at its one end to said diaphragm so as to longitudinally move with said diaphragm when pressure change within the tire occurs; a snap-action spring blade fixed at the central portion thereof on a generally intermediate portion of said actuating rod and having a pair of movable contacts at the opposed positions thereof, said spring blade having first and second states of operation thereof and changing its states when it receives two opposite moments about the central portion thereof, said first state being a state in which said movable contacts are near to said diaphragm and said second state being a state in which said movable contacts are remote from said diaphragm; and a pair of bimetallic support members fixedly disposed in said first chamber so that said spring blade is interposed between said support members and said diaphragm, said support members being constructed to bend toward said second chamber when heated and being provided with a pair of stationary contacts respectively contacting with said movable contacts when said spring blade moves into said second state thereof.