Browse Prior Art Database

Keyboard Erase Control

IP.com Disclosure Number: IPCOM000051794D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Schaefer, JO: AUTHOR

Abstract

This simple, low-cost mechanism provides keyboard control of the erase function on a fixed print mechanism typewriter. Also, since the control is on the keyboard, a sound shield, or hood, can be used without interfering with the operator erase function.

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Keyboard Erase Control

This simple, low-cost mechanism provides keyboard control of the erase function on a fixed print mechanism typewriter. Also, since the control is on the keyboard, a sound shield, or hood, can be used without interfering with the operator erase function.

One important feature of this mechanism is that a single keylever 10 provides backspace and erase control to the typewriter. This is accomplished by taking advantage of a limited, inherent longitudinal axis of rotation for all keylevers. It can be seen that depressing the backspace portion of the single keybutton 12 introduces a counterclockwise rotation of the keylever 10 along its longitudinal axis, while depressing the erase portion introduces clockwise rotation.

Referring to Fig. 1, there is shown the keylever 10 with extension 14. This extension 14 normally passes by the bellcrank extension 16 during backspace actuation. However, during erase actuation, the extension 14 swings leftwardly (as the keylever pivots clockwise on its longitudinal axis) to be in the path of bellcrank extension 16. Continued depression of the keylever causes the extension 14 to engage and pivot the bellcrank 18. This action, in turn, pushes the follower 20 leftwardly to position the extension 22 over the cam 24. During a subsequent print operation, the cam 24 is effective to rotate the follower 20 clockwise, causing the extension 26 to rotate the ribbon lift cradle 28 via tab 30.

Referring to the timing plot in...