Browse Prior Art Database

Magnetic Key Mechanism

IP.com Disclosure Number: IPCOM000078359D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Sulich, M: AUTHOR [+2]

Abstract

Shown is a key mechanism which is capable of high-speed operation and in which the switching action always occurs at precisely the same location, and with the same feel for each operation. This key has special utility for manual key mechanisms used in terminals for data-processing systems, business machines and communication devices.

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Magnetic Key Mechanism

Shown is a key mechanism which is capable of high-speed operation and in which the switching action always occurs at precisely the same location, and with the same feel for each operation. This key has special utility for manual key mechanisms used in terminals for data-processing systems, business machines and communication devices.

Key mechanism 1 is mounted on a printed-circuit board 2. Key 1 and board 2 are parts of a keyboard assembly. Key 1 comprises an housing 3 and an internal operating mechanism, actuatable by manual pressure applied to button 4.

Button 4 is attached by pin 5 to the upper end of a reciprocating plunger, which comprises shaft 6 having an upper bearing 7 and a lower bearing 8 connected by pin 9. The plunger is normally subjected to an upward biasing force provided by coaxial permanent magnets 10 and 11. Bearings 7 and 8 slide within chamber 12 of the upper section of housing 3. The upward displacement of the plunger is limited by the engagement of stop 13 with the upper surface of bearing 7, while the downward displacement of the plunger is limited by the abutment of flange 14 on upper edge 15 of housing 3.

Bearing 7 and housing 3 are designed so that at the upper displacement position of the plunger, the magnetic center line 16 of magnet 10 is displaced a finite distance below the magnetic center line 17 of magnet 11. Thus a constant magnetic-biasing force exists, which holds the plunger in its upper position to mai...