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Pressure responsive electric switch, particularly an evaporator thermostat for refrigerators

  • US 4,196,326 A
  • Filed: 10/12/1978
  • Issued: 04/01/1980
  • Est. Priority Date: 10/17/1977
  • Status: Expired due to Term
First Claim
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1. A pressure responsive electric switch assembly, comprising, an actuating element mounted for displacement between first and second extreme positions, switch means actuated by said actuating element having on and off states corresponding to said positions, pressure responsive motor means responsive to applied pressures biasing said actuating element in the one direction, displacement control means for controlling the displacement of said actuating element during a constantly increasing motive pressure applied to said motor means to provide a substantially null displacement for a substantial intermediate pressure range between upper and lower pressure ranges, said displacement control means including first and second series connected spring means for biasing said actuating element in the off direction and a coupling member connecting said first and second spring means, anchor means for holding one end of said first spring means in a relatively fixed position, means attaching one end of said second spring means to said actuating element, stationary first abutment means for arresting movement of said coupling member after a predetermined displacement at a position corresponding to a predetermined lower pressure applied to said motor means, second abutment means attached to and carried by said actuating element for engagement with said coupling member when said applied pressure is lower than a predetermined higher pressure applied to said motor means, said first and second abutment means being effective to prevent said first and second spring means from deforming during said intermediate pressure range.

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