Two-stage temperature switch
AssigneeBehr-Thomson-Dehnstoffregler GmbH & Co.
InventorRoland Saur
Life of this patent
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Abstract
An electrical switch assembly including two separate, temperature-dependent electrical switches, one of the electrical switches being substantially mechanically acting and the second of the electrical switches being a non-mechanical, solid-state switch. The mechanical switch may be a bimetallic switch of various configurations or may consist of a snap or toggle switch actuated by the expansion of a suitable fluid, for example a wax mixture. The solid-state switch element may be a resistive element which inhibits the electrical conduction upon the occurrence of elevated or lowered temperature, depending on the type of material used. Various embodiments of the mechanical portion of the switch assembly are presented.
Claims14
An electrical switch assembly responsive to temperature of a coolant in a cooling system of an internal combustion engine, the assembly comprising:
- a housing against at least a portion of which the coolant is to come;
- an insulating contact pin plate closing off said housing;
- at least a first contact pin and a second contact pin extending through said contact pin plate;
- a first switch arranged in said housing, said first switch consisting of a temperature-dependent semiconductor element which is positioned between said housing and said contact pin plate, is in electrical series with said first contact pin in a first electrical circuit and is coupled thermally to said housing;
- a second switch arranged in said housing, said second switch consisting of a temperature-dependent mechanical switching element which is connected in series with said second contact pin in a second electrical circuit and is thermally coupled to said housing independently of said first switch, said first switch and said switching element being thermally coupled not in series but in parallel to said housing and wherein triggering temperature of said second switch is different from that of said first switch.
Dependencies are inferred from the claim text.