×

Apparatus for selectively varying keyboard switching force

  • US 5,220,318 A
  • Filed: 08/20/1990
  • Issued: 06/15/1993
  • Est. Priority Date: 12/22/1988
  • Status: Expired due to Term
First Claim
Patent Images

1. A keyboard array including a plurality of switch assemblies, each switch assembly comprising a switch body, a member supporting the switch body to accommodate movement between first and second spatial positions, and apparatus for controlling the amount of force necessary to cause one of said switch assemblies to move from the first to the second spatial positions, said apparatus comprising:

  • spring means positioned between the switch body and the supporting member for exerting a first biasing force against the switch body toward said first position;

    magnetic permeable means on the switch body;

    a multi-turn coil for generating a magnetic field aligned to exert on said magnetic permeable means a second biasing force opposing said first biasing force; and

    power means for supplying an electrical current to said coil for generating said magnetic field to selectively vary said second biasing force, thereby controlling the amount of force necessary to cause the energized switch assembly to move from the first to the second spatial position.

View all claims
  • 4 Assignments
Timeline View
Assignment View
    ×
    ×