Browse Prior Art Database

Dual Pitch Homing System

IP.com Disclosure Number: IPCOM000077597D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Abell, WA: AUTHOR [+2]

Abstract

A pair of racks 20 and 21 cooperate with holding and transport pawl groups 22 and 23, respectively, as disclosed in Belgian Patent 767,627. Input motion to rack 21 is selectively controlled to produce proportional letter spacing, fixed ten-pitch spacing or fixed twelve-pitch spacing. To assure flush margins and columns in any mode, it is necessary to limit termination of long functions such as carrier return and tabulation to only those character locations corresponding to ten or twelve pitch. This is accomplished by providing rack 20 with ten teeth per inch, providing rack 21 with twelve teeth per inch, and providing the pawls of groups 22 and 23 with interpawl spacing of one-sixtieth of an inch.

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Dual Pitch Homing System

A pair of racks 20 and 21 cooperate with holding and transport pawl groups 22 and 23, respectively, as disclosed in Belgian Patent 767,627. Input motion to rack 21 is selectively controlled to produce proportional letter spacing, fixed ten- pitch spacing or fixed twelve-pitch spacing. To assure flush margins and columns in any mode, it is necessary to limit termination of long functions such as carrier return and tabulation to only those character locations corresponding to ten or twelve pitch. This is accomplished by providing rack 20 with ten teeth per inch, providing rack 21 with twelve teeth per inch, and providing the pawls of groups 22 and 23 with interpawl spacing of one-sixtieth of an inch.

A tab pawl 24 is operable to hold the print position at the end of either a line return or tabulation operation. pawl 24 is mounted for vertical sliding movement on its support rod 25 to be displaced by actuating lever 26 into alignment selectively with either the ten-pitch rack 20 or the twelve-pitch rack 21. A long function such as carrier return or tab is initiated by actuator 27 pivoting arm 28 to lift pawls 22, and 24 from the racks 20. Latch 29 holds the holding pawls 22 out of rack 20 independently of the tab pawl 24.

A tab operation is selected by also operating actuator 30 to permit latch 31 to trap arm 28 in its displaced position. Operations in the twelve-pitch mode are also accompanied by operation of actuator 32, to displace holdin...