Fluid pressure operated electrical switch
AssigneeAisin Seiki Kabushiki Kaisha
InventorsHiromu Kuromitsu, Yoshiharu Adachi
Life of this patent
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Abstract
A fluid pressure operated electrical switch has a piston element subject to an operating fluid pressure on its acting end face for actuating an electrical switch. The switch employs a limiting member for limiting motion of the piston element to a predetermined extent in order to prevent the switch from being damaged due to overstroke of the piston element. The limiting member includes a flange at the rearmost end of the piston element and an annular shoulder in a bushing which is closely fitted within a port of a switch body for the operating fluid pressure. The piston element is loosely fit in the bushing with the flange in engagement within the shoulder of the bushing such that the flange and shoulder cooperate to provide limitation of the stroke of the piston element.
Claims5
A fluid pressure operated switch comprising:
- a hollow body;
- an electrical switch member operatively associated with the body;
- a plunger slidingly mounted in the body;
- switch engaging means carried by the switch member for operative engagement with the plunger at a front end portion of the plunger;
- a piston element slidingly mounted in the body in alignment with and engaging a rear end portion of the plunger;
- a compressed coil spring operatively associated with said rear end portion of the plunger for normally biasing the plunger toward abutting engagement with the front end portion of the piston element;
- sealing means mounted on the piston element for sealing the piston element within the body, said body having a port formed therein for admitting fluid under pressure and to which the piston element is exposed at an acting rear end face portion thereof;
- means for limiting motion of the piston element adjacent said rear end face portion of the piston element;
- and
- adjusting means in screw threaded engagement with the body for movably anchoring the coil spring at an end portion thereof adjacent said front end portion of the plunger wherein said means for limiting motion of the piston element further comprises a cage mounted in the port and having an internally extending annular seat disposed around the piston element, a ball movably housed in the cage, and a spring member for urging said ball toward engagement with said annular seat and toward abutment against the rear end portion of the piston element.
Dependencies are inferred from the claim text.