Means for avoiding accidental actuation of a critical function key
US4362408A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1980 |
| Grant date | Dec 7, 1982 |
| Priority date | — |
| Expiry date | Dec 1, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H13/50
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A keyboard having a plurality of keys thereon, with each key being moveable from a rest position along an actuation path having a makepoint therealong, whereby completion of an electrical circuit is effected by moving a key with a predetermined force along its actuation path to its associated said makepoint. Each of the keys has means for restoring it towards its rest position. At least one of the keys is designated as a special key and it has warning means associated therewith and positioned with respect to the special key and keyboard so as to increase the force (above the predetermined force) required to actuate the special key. The increase in force provides tactile feedback to an operator of the keyboard before the special key's associated makepoint is reached to thereby warn said operator that he is about to actuate the special key. The warning means is made of resilient material, has a general, washer-like shape, and is positioned under the key cap of the special key.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.