PRESSURE SENSITIVE MAT SWITCH CONSTRUCTION

• US 3,830,991 A
• Filed: 07/24/1973
• Issued: 08/20/1974
• Est. Priority Date: 07/24/1973
• Status: Expired due to Term

• Current Assignee: United Technologies Automotive, Inc. (Lear Corporation)
• Original Assignee: Gideon A. Durocher
• Inventors: Durocher, Gideon A.
• Primary Examiner(s): Smith, Jr., David
• Application Number:
  US05/382,138
• Time in Patent Office: 392 Days
• Field of Search: 200/86R,85R 340/272,278
• US Class Current: 200/86.00R
• CPC Class Codes: H01H 1/029 comprising conducting material dispersed in an elastic support or binding material
• CPC Class Codes: H01H 3/141 Cushion or mat switches

Abstract

A pressure sensitive switch useful in a mat of the kind adapted to operate a door in response to a person'"'"''"'"'s stepping on the mat comprises a switch assembly composed of a pair of sheet-like electrical conductors between which is interposed a sheet of resiliently compressible and expansible non-conductive material such as foamed rubber or plastic having a plurality of openings therethrough in each of which is accommodated a bridging member operable to establish a conductive path between the two conductors when the latter are moved relatively toward one another in response to the application to the mat of a compressive force. The switch assembly is enclosed within a nonconductive rubber or plastic sheath. Conductive wires connected to the two conductors of the switch assembly extend through the sheath for connection to a source of energy and to the actuating mechanism for the door to be operated. Means are provided for limiting the compressive force to which said bridging member may be subjected.

Claims

1. A pressure sensitive switch assembly comprising a resilient, compressible, non-conductive member having an opening therethrough;

electrical conductors spaced apart by said nonconductive member, the compressibility of said non-conductive member enabling relative movement of said conductors toward one another;

bridging means accommodated in said opening and operable in response to relative movement of said conductors toward one another to establish a conductive path between said conductors; and

means for limiting the compressive force to which said bridging means may be subjected irrespective of the extent to which said non-conductive member may be compressed.

2. An assembly according to claim 1 wherein said bridging means normally is non-conductive and is rendered conductive in response to compression thereof.

3. An assembly according to claim 1 wherein said bridging means normally is conductive and has a height less than the spacing between said conductors when said non-conductive member is in its uncompressed condition.

4. An assembly according to claim 1 wherein said limiting means comprises a relatively incompressible member encircling said bridging member.

5. An assembly according to claim 4 wherein said relatively incompressible member is interposed between said non-conductive member and one of said conductors.

6. An assembly according to claim 1 including a non-conductive sheath enclosing said assembly.

7. An assembly according to claim 6 wherein said sheath is composed of resilient material.

8. An assembly according to claim 1 including means for connecting at least one of said conductors to a source of electrical energy.

9. An assembly according to claim 1 wherein at least one of said conductors comprises a metallic screen.

10. An assembly according to claim 9 wherein said screen is adhesively secured to said non-conductive member.

11. An assembly according to claim 1 whereiN said bridging member comprises an elastomer throughout which is dispersed a plurality of electrically conductive particles.

12. An assembly according to claim 11 wherein the quantity of said particles is such that a sufficient number thereof are in engagement to establish a conductive path through said elastomer without the application of external compressive force to said elastomer.

13. An assembly according to claim 11 wherein the quantity of said particles is such that a conductive path may be established through said elastomer only upon the application of an external compressive force to said elastomer.

14. A pressure sensitive switch assembly comprising a pair of spaced apart sheet-like conductors;

a sheet-like, non-conductive, resilient, relatively compressible and expansible member interposed between said conductors and having a plurality of spaced apart openings therethrough, the compressibility of said non-conductive member enabling relative movement of said conductors toward one another;

a bridging member accommodated in each of said openings and operable in response to relative movement of said conductors toward one another to establish an electrically conductive path between said conductors; and

relatively incompressible limit means interposed between said conductors adjacent each of said bridging members for limiting the extent of movement of said conductors toward one another and consequently limiting the compressive force to which said bridging members may be subjected.

15. An assembly according to claim 14 wherein each of said limit means comprises an annulus encircling a bridging member.

16. An assembly according to claim 15 wherein each of said annuli is interposed between said non-conductive member and one of said conductors.

17. An assembly according to claim 14 including a resilient, non-conductive sheath enclosing said assembly.