Fail safe membrane switches

• US 20080202911A1
• Filed: 05/05/2006
• Published: 08/28/2008
• Est. Priority Date: 05/16/2005
• Status: Active Grant

• Current Assignee: Weber Precision Graphics
• Original Assignee: Weber Precision Graphics
• Inventors: Weber, Henry G., Estrada, Manuel, Rowe, John, Duhon, Edward W., Johnson, Jeffrey F.
• Granted Patent: US 7,645,956 B2
• Time in Patent Office: Days
• US Class Current: 200/5R
• CPC Class Codes: H01H 1/06 characterised by the shape or structure of the contact-making surface, e.g. grooved
• CPC Class Codes: H01H 2203/008 Wires
• CPC Class Codes: H01H 3/141 Cushion or mat switches

Abstract

Membrane switches have at least one trace with two leads, such that its integrity can be tested during deployment of the switch.

Claims

1. A membrane switch comprising:

first and second opposing traces that can be contacted together to form an electrical circuit; and

wherein at least one of the traces has two leads such that its integrity can be tested while the switch is deployed.

2. The switch of claim 1, wherein the first trace has the two leads, and the second trace includes two additional leads.

3. The switch of claim 1, wherein one of the two leads electrically connects to the first trace and the other of the two leads electrically connects to the second trace, and the two traces are electrically coupled.

4. The switch of claim 3, wherein the two traces are electrically coupled through at least one of a resistor and a diode.

5. The switch of claim 1, further comprising a third trace, that cooperates with the first and second traces to establish at least two separately detectable zones.

6. The switch of claim 2, wherein the third trace has two further leads that can be used to test integrity of the third trace during deployment of the switch.

7. The switch of claim 1, further comprising a plurality of spacers disposed adjacent one of the traces.

8. A floor mat comprising the switch of claim 1.

9. The floor mat of claim 8, having a dimension along at least one axis or diameter is at least 24 inches.

10. The floor mat of claim 8, having a dimension along at least one axis or diameter is at least 36 inches.

11. The floor mat of claim 8, having a dimension along at least one axis or diameter is at least 96 inches.

12. The switch of claim 1, further comprising closely spaced traces having circuits that are closed differentially as a function of pressure in an area near the traces.

13. A safety mat containing a failsafe membrane switch having a thickness of no more than ¼

^th inch.