Browse Prior Art Database

Counterweight Space Bar Mechanism

IP.com Disclosure Number: IPCOM000089141D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Harris, RH: AUTHOR

Abstract

This article describes a space bar mechanism that is immune to actuation by external vibrations and that allows the use of a regular return spring in a key switch module which does not require a different force characteristic to overcome the greater mass of the elongated space bar. A number of previous space bar mechanisms have utilized torsional bars connected to each end of the space bar as a means of guiding the space bar and for supporting it so that actuation near either end would be transferred to the opposite end. In such systems the addition of these parts to an elongated key button that is already much heavier than a regular key button produces a system with considerably more mass than a regular key module can sustain.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Counterweight Space Bar Mechanism

This article describes a space bar mechanism that is immune to actuation by external vibrations and that allows the use of a regular return spring in a key switch module which does not require a different force characteristic to overcome the greater mass of the elongated space bar. A number of previous space bar mechanisms have utilized torsional bars connected to each end of the space bar as a means of guiding the space bar and for supporting it so that actuation near either end would be transferred to the opposite end. In such systems the addition of these parts to an elongated key button that is already much heavier than a regular key button produces a system with considerably more mass than a regular key module can sustain. The larger mass requires a larger than normal return spring in the key module to produce the same key force as regular smaller key button. The return force on the space bar must be increased further beyond this point to prevent space bar actuation that may result from external vibrations. The present article describes a space bar mechanism that is immune to such actuation by external vibration and that allows the use of a regular force return spring instead of a special heavy duty spring.

The figure, which illustrates the space bar mechanism for a key board, is a vertical section taken through the key mechanism to show its method of operation. Space bar key top 4 has inserts 3 which support it as it passes through guide holes 2A on portions 3A. Inserts 3 are flat pieces of metal or other suitable material seen in the figure in an edgewise view. An aperture 3D is punched or drilled through insert 3 and through which passes a projection 1D of a metal L-shaped member 1. L-shaped member 1 is supported in an aperture 2B in a support block which is part of the key module 2. The L-shaped member 1 forms a counter-weight to the mass of the key button 4 together with the guide members 3 and a portion of the L-shaped member 1,...