Browse Prior Art Database

Escapement and Backspace Mechanism

IP.com Disclosure Number: IPCOM000093989D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Palmer, LE: AUTHOR

Abstract

A combination escapement and backspace mechanism is shown. Pawl 10 normally engages and holds a spring-biased rack 11 against movement in the forward escapement direction indicated by arrow 12. Pawl 10 has an elongated slot 13 which receives a stud 14 mounted on the end of pivoted lever 15.

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Escapement and Backspace Mechanism

A combination escapement and backspace mechanism is shown.

Pawl 10 normally engages and holds a spring-biased rack 11 against movement in the forward escapement direction indicated by arrow 12. Pawl 10 has an elongated slot 13 which receives a stud 14 mounted on the end of pivoted lever 15.

During a normal forward escapement operation, escapement trip lever 16 is pivoted counterclockwise to engage and pivot pawl 10 from the rack 11. Spring 17 moves pawl 10 forward by a distance equal to the length of slot 13. The rear end of pawl 10 moves from beneath the tab of trip lever 16. Pawl 10 is then pivoted back into engagement with rack 11 by spring 17. Rack 11 moves in the forward escapement direction under its spring bias until the forward edge of slot 13 engages stud 14.

In a backspace operation, backspace link 19 is pulled in the direction of arrow
20. This moves lever 15, pawl 10, and rack 11 as a unit to the right in the backspace direction by a distance greater than the standard escapement increment at a relatively low velocity. The pulling force on link 19 is released. Spring 21 moves lever 15 and pawl 10 back to the left against stop 22 at a relatively high velocity. Pawl 10 overrides one of the teeth on rack 11. This is because rack 11 and the apparatus associated with it are much heavier than pawl 10 and lever 15.

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