Environmentally sealed piezoelectric sensing assembly for electrical switch

Claim 2

A sensing assembly for an electrical switch, said sensing assembly comprising: enclosure means defining a cavity and including support means defining a supporting ledge and a stop means; a flexible generally planar member resting at its edge portions upon said ledge in overlying, closely spaced relation to said stop means whereby said planar member is permitted flexure within the space between said planar member and said stop means, said stop means being engagable by said planar member to limit the degree of said flexure, and said space being in communication with said cavity; a generally planar piezoelectric element attached to one of the surfaces of said flexible member and characterized on deformation by generation of an electrical signal; electrical conductor means coupled to said piezoelectric element and extending into said cavity for carrying said signal; and resiliently deformable potting means filling said space and extending into said cavity to block entry of moisture into said space and said cavity, the resilient deformability of said potting means enabling flexure of said flexible member and said piezoelectric element for generating said signal.

Claim 3

A sensing assembly according to claim 1 wherein said piezoelectric element is attached to the exteriorly directed surface of said flexible member.

Claim 4

A sensing assembly according to claim 1 wherein said piezoelectric element is adhesively bonded to said exteriorly directed surface.

Claim 5

A sensing assembly according to claim 1 wherein said flexible member comprises a relatively thin element made of electrically conductive material bonded to said exteriorly directed surface by a thin, electrically transparent layer of adhesive material.

Claim 6

A sensing assembly according to claim 2 and including a layer of electrically insulating material located upon the exteriorly directed surfaces of said flexible member and said piezoelectric element.

Claim 7

A sensing assembly according to claim 1, and including electrical circuit means coupled to said electrical conductor means, and located in a portion of said cavity filled with said potting means.

Claim 8

A sensing assembly according to claim 1 wherein said support means comprises a wall having an opening affording said communication, and engagable by said flexible member for limiting said flexure.

Claim 9

A sensing assembly comprising: enclosure means defining a cavity and including a rigid wall having an exteriorly opening circular recess, the edge margins of said recess being formed to define a supporting ledge, said wall further having a flow passage providing communication between said recess and said cavity; a flexible generally planar member spanning said recess and resting at its edge portions upon said ledge; a generally planar piezoelectric element attached to one of the surfaces of said flexible member and characterized on deformation by generation of an electrical signal; electrical conductor means coupled to said piezoelectric element and extending into said cavity for carrying said signal; adhesive means bonding said piezoelectric element to the exteriorly directed surface of said flexible member; an electrically insulating member overlying the exteriorly directed surfaces of said piezoelectric element and said flexible member; electrical circuit means in said cavity and coupled to said electrical conductor means; and resiliently deformable potting means filling said recess to block entry of moisture into said recess, and also filling said flow passage and the portion of said cavity surrounding said electrical circuit means, the resilient deformability of said potting means enabling flexure of said flexible member and said piezoelectric element, upon application of external pressure, through deformational flow of said potting means in said recess from said recess, through said flow passage and into said cavity, said flow of said potting means being oppositely directed upon removal of said external pressure.

Claim 10

A sensing assembly comprising: enclosure means defining a cavity and including a rigid wall having an exteriorly opening circular recess, the edge margins of said recess being formed to define a supporting ledge, said wall further having a flow passage providing communication between said recess and said cavity; a flexible generally planar member spanning said recess and resting at its edge portions upon said ledge; a generally planar piezoelectric element attached to one of the surfaces of said flexible member and characterized on deformation by generation of an electrical signal; electrical conductor means coupled to said piezoelectric element and extending into said cavity for carrying said signal; adhesive means bonding said piezoelectric element to the exteriorly directed surface of said flexible member; an electrically insulating member overlying the exteriorly directed surfaces of said piezoelectric element and said flexible member; electrical circuit means in said cavity and coupled to said electrical conductor means; and resiliently deformable potting means filling said recess to block entry of moisture into said recess, and also filling said flow passage and the portion of said cavity surrounding said electrical circuit means, the resilient deformability of said potting means enabling flexure of said flexible member and said piezoelectric element, upon application of external pressure, through deformational flow of said potting means in said recess from said recess, through said flow passage and into said cavity, said flow of said potting means being oppositely directed upon removal of said external pressure.

Claim 11

A sensing assembly according to claim 8 wherein said potting means is a silicone dielectric gel.

Claim 12

An electrical switch according to claim 8 wherein said recess includes a base in spaced relation with said flexible member, and said flow passage extends through said base.

Claim 13

A sensing assembly according to claim 8 wherein said flexible member comprises a relatively thin element made of electrically conductive metal.

Claim 14

A sensing assembly according to claim 8 wherein said adhesive means comprises a layer of epoxy material sufficiently thin as to be electrically transparent.

Claim 15

A sensing assembly according to claim 8 wherein said electrical conductor means comprises a pair of electrical conductors coupled to opposite surfaces of said piezoelectric element.

Claim 16

A sensing assembly according to claim 9 wherein said rigid wall of said enclosure means includes an opening adjacent said recess and extending into said cavity, and said electrical conductors extend from said recess, through said opening and into said cavity, and wherein said potting means fills said opening to surround said electrical conductors.

Claim 17

A sensing assembly according to claim 8 and including an electrically insulating spacer overlying said flexible member and said piezoelectric element, and generally flush with the exteriorly directed surface of said rigid wall of said enclosure.

Claim 18

A sensing assembly according to claim 8 wherein said recess includes a base engageable by said flexible member for limiting the degree of deformation of said piezoelectric element.

Claim 19

Hot tub electrical switch means for operating electrically operated apparatus, and including a sensing assembly comprising: enclosure means defining a cavity and including support means defining a support ledge and a stop means; a flexible generally planar member resting at its edge portions upon said ledge in overlying, closely spaced relation to said stop means whereby said planar member is permitted flexure within the space between said planar member and said stop means, said stop means being engagable by said planar member to limit the degree of said flexure, and said space being in communication with said cavity; a generally planar piezoelectric element attached to one of the surfaces of said flexible member and characterized on deformation by generation of an electrical signal; electrical conductor means coupled to said piezoelectric element and extending into said cavity for carrying said signal; resiliently deformable potting means filling said space and extending into said cavity to block entry of moisture into said space and said cavity, the resilient deformability of said potting means enabling flexure of said flexible member and said piezoelectric element for generating said signal; and electrical circuit means coupled to said electrical conductor means and located in a portion of said cavity filled with said potting means, said circuit means being adapted for connection to pump apparatus for operating said pump appartus responsive to said generation of said electrical signal.

Claim 20

Hot tub electrical switch means for operating electrically operated apparatus, and including a sensing assembly comprising: enclosure means defining a cavity and including support means defining a support ledge and a stop means; a flexible generally planar member resting at its edge portions upon said ledge in overlying, closely spaced relation to said stop means whereby said planar member is permitted flexure within the space between said planar member and said stop means, said stop means being engagable by said planar member to limit the degree of said flexure, and said space being in communication with said cavity; a generally planar piezoelectric element attached to one of the surfaces of said flexible member and characterized on deformation by generation of an electrical signal; electrical conductor means coupled to said piezoelectric element and extending into said cavity for carrying said signal; resiliently deformable potting means filling said space and extending into said cavity to block entry of moisture into said space and said cavity, the resilient deformability of said potting means enabling flexure of said flexible member and said piezoelectric element for generating said signal; and electrical circuit means coupled to said electrical conductor means and located in a portion of said cavity filled with said potting means, said circuit means being adapted for connection to pump apparatus for operating said pump appartus responsive to said generation of said electrical signal.