Browse Prior Art Database

Add On Shift Lock Mechanism

IP.com Disclosure Number: IPCOM000049932D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Duranske, RG: AUTHOR [+2]

Abstract

Alphanumeric data entry keyboards are sometimes required to implement typewriter functions, such as case shift or font change operations. These are normally achieved by a shift key. As is often the case, it is necessary to lock the shift for a sequence of characters for this purpose.

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 53% of the total text.

Page 1 of 3

Add On Shift Lock Mechanism

Alphanumeric data entry keyboards are sometimes required to implement typewriter functions, such as case shift or font change operations. These are normally achieved by a shift key. As is often the case, it is necessary to lock the shift for a sequence of characters for this purpose.

An easily added shift lock key and mechanism is described here.

Fig. 1 illustrates an exploded view of the mechanism. A shift key 1 is normally provided on the keyboard (not shown). The shift lock mechanism employs a shift lock key 2 with latch elements 3, 4, 5 and
6. An interconnecting rod 7 connects two shift keys 1 and 13 to unlatch the shift lock mechanism, as will be described later.

A flat leaf or torsion spring 8A having a reaction arm 8A is mounted on the interconnecting rod 7 at the left hand shift key 1 position. The torsion spring 8A is made to provide torsion against latch element 3 in the counterclockwise direction tending to force element 3 into engagement with latch surface 6 in notch 4 in the key 2. The interconnecting rod 7 is mounted in pivots 10 and 11 which are affixed by retaining ring portions 9 as will be shown in Fig. 2. The ring portions 9 slip around the key stem and are held in place by a snap ring, as will be disclosed below.

A pawl release arm 12 is positioned to be contacted by the right hand shift key 13 and by the left hand shift key 1 to cause a clockwise torque to be applied to the latch mechanism to release the lock function.

Fig. 2 illustrates an enlarged partially cut-away section of the action at keys 1 and 2 from Fig. 1. Shown in dotted lines, keybuttons 1 and 2 take on position A when the latch is released. In normal operation, depression of either shift key 1 or 13 rocks the associated pawl 14 or 12, respectively, to disengage the latch mechanism. If the mechanism is not engaged, there is no interaction with these pawls. Button 1 disengages the latch when it is depressed. A simultaneous depression of both keys w...