Patent · US Expired

Key spring

US4793601A · kind A · utility

5Cited by

7References

4Claims

0Family size

Assignee

Alcatel N.V. · NL

Inventors

Peter Wild · Krefeld, DE
Johannes Rometsch · Rickenbach, CH
Werner Frey · Thalwil, CH
Karl Iseli · Wädenswil, CH

Key dates

Filing date	Sep 7, 1983
Grant date	Dec 27, 1988
Priority date	—
Expiry date	Sep 7, 2003

Classification

Technology area (CPC H)Electricity
CPC primaryH01H13/36
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

In order to save space and manufacturing costs a pull-off effect for the operation of a key should be achieved by using a single spring. Thus the spring must have an arc-like force vs. displacement characteristic having a maximum of force about on half-way of the key stroke. This is achieved by a meander-like shaped spring (1) of flat material having two end loops (2, 3) of equal height and one middle loop (4) of about twice this height, all these loops lying within the same plane. The mounted spring is pretensioned in two directions being perpendicular to each other and lying in said plane, the operating force being applied to the top (7) of the middle loop.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.