Buckling spring torsional snap actuator

• US 4,118,611 A
• Filed: 08/30/1977
• Issued: 10/03/1978
• Est. Priority Date: 08/30/1977
• Status: Expired due to Term

• Current Assignee: IBM Information Products Corp. (Ninestar Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Harris, Richard Hunter
• Primary Examiner(s): Norton, Donald F.
• Application Number:
  US05/829,039
• Time in Patent Office: 399 Days
• Field of Search: 200/67 R, 200/67 A
• US Class Current: 200/408
• CPC Class Codes: H01H 13/30 one end of spring transmitting movement to the contact member when the other end is moved by the operating part
• CPC Class Codes: H01H 2235/012 Euler spring

Abstract

A torsional or rocker switch actuator is described that uses the torsional moment of a buckling compression spring column to rock the actuator member on a pivot. A catastrophically buckling compression column spring is used and the reaction moment which occurs as the spring buckles is applied to rock an actuator back and forth between open and closed positions with cooperating contacts beneath the actuator. A non-teasible, snap action, tactile feedback, key mechanism of extreme mechanical simplicity and high reliability is achieved.

Claims

1. In an electrical key actuating mechanism having a key top, a housing having means for slidably receiving said key top for vertical motion thereof, a pivoting rocker type electrical actuating means in said housing opposite said key top, electrical means for actuation by said electrical actuating means, and also having a buckling compression spring means under precompression and mounted between said key top and said pivoting rocker type electrical actuating means, the improvements comprising:

lateral deflection offset spring mounting means within said housing bearing against said buckling compression spring and displacing the central portion thereof relative to its ends in a first chosen direction for promoting buckling of said buckling compression spring in said first chosen direction;

mounting means on said key top for pivotally mounting the proximal end of said buckling compression spring; and

mounting means on said rocker for mounting the distal end of said buckling compression spring with an edge of said spring colinear with said pivot of said rocker.

2. Apparatus as described in claim 1, wherein:

said lateral deflection offset spring mounting means comprises an angled mounting surface on said mounting means for said proximal end of said buckling spring, said angled mounting surface deflecting the portion of said spring at a point along said spring intermediate said distal and proximal ends laterally in said first chosen direction.

3. Apparatus as described in claim 2 and further comprising:

said angled mounting surface for said proximal end of said spring means pivotally supports the edge of said spring on the side thereof facing in said first chosen direction.

4. Apparatus as described in claim 3, wherein:

the pivot point of said pivoting rocker type electrical actuating means is colinear with an edge of said buckling compression spring means.