Claims
- 1. A pressure actuated switching device, which comprises:
- a) a layer of compressible piezoresistive material;
- b) a base below said layer of piezoresistive material;
- c) at least two insulative spacer elements positioned between said piezoresistive material and said base, said spacer elements each having an upper layer of conductive material, and each insulative spacer element having at least one aperture, said apertures being aligned, configured, and dimensioned to form at least one void defined by stepped sides said void has a relatively large diameter opening adjacent the piezoresistive material and a relatively small diameter opening adjacent the base.
- 2. The device of claim 1 wherein said at least two spacer elements form a stack of spacer element layers having a conductive layer on an uppermost spacer element layer, said conductive layer being in electrical contact with said piezoresistive material.
- 3. The device of claim 2 wherein said piezoresistive material is a foam material resiliently movable in response to downwardly directed force applied thereto through said void and into successive contact with at least one other conductive layer.
- 4. The device of claim 3 wherein said at least one void is generally conical in shape.
- 5. The device of claim 1 further including an insulative flexible cover sheet disposed above said layer of piezoresistive material.
- 6. The device of claim 1 wherein said spacer elements are fabricated from a rigid material.
- 7. The device of claim 1 wherein said base comprises an insulative layer and a conductive material, said conductive material being joined to an upper surface of said insulative layer.
Parent Case Info
This is a divisional of application Ser. No. 08/429,683 filed Apr. 27, 1995 U.S. Pat. No. 5,695,859.
US Referenced Citations (47)
Foreign Referenced Citations (5)
Number |
Date |
Country |
0167341 |
Jan 1986 |
EPX |
0293734 |
Dec 1988 |
EPX |
1942565 |
Apr 1971 |
DEX |
2026894 |
Dec 1971 |
DEX |
2045527 |
Oct 1980 |
GBX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
429683 |
Apr 1995 |
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