Browse Prior Art Database

Sparkless Switch

IP.com Disclosure Number: IPCOM000084714D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Gnanasambandan, JP: AUTHOR [+2]

Abstract

The switch is operated by a key 1 of a keyboard. Depression of the key 1 causes the tip 2 of an intermediate member 3 pivoted at 4 to move, since the tip 2 is located in a recess 5 in the shaft of the key. Member 3 is pivotally attached to a bar 6 by a pivot 7. Bar 6 can move longitudinally. The remote end of bar 6 is formed with an arm 8 which engages a shutter 9 pivoted at 10 and is formed with an aperture 11.

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Sparkless Switch

The switch is operated by a key 1 of a keyboard. Depression of the key 1 causes the tip 2 of an intermediate member 3 pivoted at 4 to move, since the tip 2 is located in a recess 5 in the shaft of the key. Member 3 is pivotally attached to a bar 6 by a pivot 7. Bar 6 can move longitudinally. The remote end of bar 6 is formed with an arm 8 which engages a shutter 9 pivoted at 10 and is formed with an aperture 11.

A light source 12 is located on one side of the shutter 9 and a photocell 13 is located on the other. Depression of key 1 causes longitudinal movement of bar 6 and rotation of shutter 9, so as to allow light from source 12 to reach the photocell 13 for a short instant to produce an electric signal.

The figure shows a plan view of shutter 9. The arm 8 engages with recess
14. A spring 15 has one end engaging an extension 16 of the shutter 9 and the other end anchored at 17. Spring 15 serves to provide a toggle action movement for shutter 9 so that its speed of movement is high, even if the speed of movement of key 1 is relatively slow.

Bar 6 is formed with a mechanical interlock preventing more than one key of the keyboard from being depressed and operating its associated switch at the same time.

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