Self-encoding key switch and keyboard and keyboard system utilizing the same
US4172251A · kind A · utility
Inventor
Key dates
| Filing date | Apr 19, 1977 |
| Grant date | Oct 23, 1979 |
| Priority date | — |
| Expiry date | Apr 19, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2239/026
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A self-encoding key switch is formed of a body having a well for storing a pool of mercury, a plurality of contact chambers with encoding contacts therein and having channel portions communicating with the well of a size to resist flow of the mercury therethrough due to surface tension of the mercury, and a plunger movable into the well to force the mercury through the channel portions into the contact chambers to momentarily connect the encoding contacts thereby providing tactile feedback, self-encoding and N-key rollover. A keyboard system utilizes a plurality of the above-described self-encoding key switches along with a register, and a strobe contact is disposed in a contact chamber of each key switch such that the trailing edge of the signal from the strobe contact precedes the breaking of electrical connection between a supply contact in the body and the encoding contacts to trigger the register and enter coded data from the encoding contacts. A keyboard formed of a plurality of the above-described, self-encoding key switches is constructed with the bodies of each of the key switches formed of a single piece of plastic material mounted on a base member carrying electrical con…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.