Fluid pressure responsive electric switch

A fluid pressure responsive electric switch comprising:

• an elongated generally tubular base member having a longitudinal axis and having a sidewall extending between a first and a second end;
• a motion transfer guide member having a central bore mounted at the first end of the base member;
• a fluid pressure responsive sensor assembly, comprising a composite actuator member sandwiched between a disc housing member with a central aperture and a housing support member with a central aperture, the disc housing member, housing support member, and the composite actuator member all having outer circular peripheral portions being welded together and being generally in alignment with the guide member, the sensor assembly and the base member being joined together;
• and
• an electric switch disposed within the base member and a motion transfer pin slidably mounted in the guide member and extending through the aperture in the housing support member between the composite actuator member and the electric switch, said composite actuator member comprising at least one member of a chosen low coefficient of thermal expansion (CTE) material and at least one member of a chosen high coefficient of thermal expansion (CTE) material;
• wherein the composite actuator member comprises at least one snap-acting disc member of a low CTE material and at least one snap-acting disc member of a high CTE material and a membrane positioned between the at least one high CTE material snap-acting disc member and the at least one low CTE material snap-acting disc member.