US 4,195,209 AGranted

Pressure responsive electrical switch and means of contact gap setting therefor

AssigneeEmerson Electric Co.

InventorKenneth P. Mlyniec

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Abstract

A pressure responsive switch for changing electrical state in response to a fluid pressure which equals or exceeds a desired pressure threshold level includes a cylindrical conductive casing. The casing defines a central, generally cylindrical cavity and at least one upper fluid inlet orifice. The casing further defines a lower opening communicating with the cavity. A non-conductive elastic membrane extends across the upper portion of the cavity beneath the fluid inlet orifice and is sealingly attached at its periphery to the interior of the casing. A conductive, pressure actuatable plunger in the upper portion of the cavity includes a pressure receiving surface directly beneath the membrane. An electrical connector is mounted by a bushing means centrally in the cavity. The connector is held out of electrical contact with a casing and has a first end extending out of the cavity through the lower opening in the conductive casing and a second end which is positioned in the cavity. A conductive spring means in the cavity provides an electrical path between the conductive casing and the plunger and applies a predetermined upward force to the plunger, urging the plunger out of contact with the second end of the connector. When the fluid admitted by the fluid inlet orifice reaches the desired pressure threshold level, the plunger will be moved downward by the fluid pressure against the force of the spring means, such that the plunger will contact the second end of the connector and provide an electrical path between the connector and the casing. The second end of the connector and the plunger thus define first and second switch contact means.

Claims7

Dependent claims

A pressure responsive switch for changing electrical switching state in response to a fluid pressure which equals or exceeds a desired pressure threshold level, comprising:

a cylindrical conductive casing having a central, generally cylindrical cavity and defining at least one upper fluid inlet orifice communicating with said cavity, said casing defining a position limiting boss extending downward adjacent said inlet orifice into said cavity, and said casing further defining a lower opening communicating with said cavity,
a nonconductive elastic membrane extending across the upper portion of said cavity beneath said fluid inlet orifice and said position limiting boss, and sealingly attached at its periphery to the interior of said casing,
a conductive, pressure actuatable plunger in the upper portion of said cavity including a pressure receiving surface directly beneath said membrane,
an electrical connector,
means mounting said electrical connector centrally in said cavity out of electrical contact with said casing such that a first end of said connector extends out of said cavity through said lower opening in said conductive casing and a second end of said connector is positioned in said cavity, and
means in said cavity providing an electrical path between said conductive casing and said plunger and applying a predetermined upward spring force to said plunger urging said plunger out of contact with said second end of said connector, the upward movement of said plunger and said membrane being limited by said position limiting boss,
whereby when the fluid admitted by said fluid inlet orifice reaches the desired pressure threshold level, said plunger is moved downward by the fluid pressure against said spring force such that said plunger contacts said second end of said connector and provide an electrical path between said connector and said casing.

4 more elements

Dependencies are inferred from the claim text.