Key element for a contactless keyboard
US4791257A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 1983 |
| Grant date | Dec 13, 1988 |
| Priority date | — |
| Expiry date | Apr 14, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/972
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In order to have a large flexibility of application with simultaneously a reasonable number of different piece parts for a so called transformer keyboard the key element is subdivided. A base (1) usable for all applications includes elements for the protection against rotation (14) and for fixing (13) it on a printed circuit board (6) without screws and without soldering operations, further elements to guide (18) the stem (2) and to limit its stroke. The stem receives a ferromagnetic core (4) within its guidance (21). The shape and the size of wall portions (2', 22) change in accordance with the desired raster of the keyboard wherein the key element is used. A cap (3) carrying the marking has the same shape for all stems and is connected to the stem in a detatchable manner (27, 33). Due to their small height these key elements are especially suited in applications for data terminal keyboards with an ergonomically good design.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.