Vandal-resistant telephone keypad switch
US4716262A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 1985 |
| Grant date | Dec 29, 1987 |
| Priority date | — |
| Expiry date | Nov 22, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2239/038
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A shielded electrical switch includes a pressure-actuated switch comprised of three layers, the top and bottom layer of which are electrically-conductive and the intermediate layer of which is a spacer layer containing apertures at the switch points. A sealing membrane is coupled over the layered switch, the membrane having thickened push-button supports overlying the switch points. The thickened push-button supports are spaced from the membrane via frustro-conical mounting portions on the membrane. This frustro-conical mounting gives the buttons the sufficient "feel" or resistance when depressed, and also insures that the switch-actuating portions of the membrane will make contact with the upper surface of the switch to insure that the switch points of the upper and lower layers of the switch will make contact via the intermediate layer. The membrane and the sealed, layered switch are, in turn, enclosed in an armored, sealed push-button enclosure. The entire assembly is thus a highly vandal-resistant, low-cost, push-button switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.