Browse Prior Art Database

Case Shift Mechanism

IP.com Disclosure Number: IPCOM000075844D
Original Publication Date: 1971-Nov-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Abell, WA: AUTHOR

Abstract

A typewriter, like that described in U. S. Patent 2,919,002, is provided with a shift mechanism contained within type element carrier 10 and driven by power from print shaft 11. Type element 12 is positioned to normally present characters selected from either hemisphere 13 or hemisphere 14, by rotative motion supplied to pulley 15. Sector gear 16 is pivoted to rocker 17 by pin 18 to drive gear 19 and type element 12 180 degrees relative to the pulley 15. Sector gear 16 normally stands out of mesh with gear 19 so as not to interfere with rotative character selection controlled intake 20. A bistable spring 21 retains gear 19 in either of two stable positions defined by studs 22 and 23, which are engaged by arm 24 carried by gear 19.

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Case Shift Mechanism

A typewriter, like that described in U. S. Patent 2,919,002, is provided with a shift mechanism contained within type element carrier 10 and driven by power from print shaft 11. Type element 12 is positioned to normally present characters selected from either hemisphere 13 or hemisphere 14, by rotative motion supplied to pulley 15. Sector gear 16 is pivoted to rocker 17 by pin 18 to drive gear 19 and type element 12 180 degrees relative to the pulley 15. Sector gear 16 normally stands out of mesh with gear 19 so as not to interfere with rotative character selection controlled intake 20. A bistable spring 21 retains gear 19 in either of two stable positions defined by studs 22 and 23, which are engaged by arm 24 carried by gear 19. Spring 21, when driven beyond its over center position, also completes positioning of gear 19.

Sector gear 16 is operated by bistable lever 25 connected thereto through rod 26, which lies along the pivot axis of the rocker 17. Lever 25 is pivoted to the carrier 10 by a pin 27. A slotted cam 28 is driven rotatively one revolution each print cycle of the typewriter. The cam 28 includes suitable crossover slots 29 and retaining slots 30. A pair of pneumatic actuators 31 and 32 are provided to urge a pin 33 from one slot 30 into the crossover slots 29, when a shift operation is desired.

Activation of actuator 31 drives pin 33 leftwardly to pivot sector gear 16 counterclockwise and throw spring 21 over center to select h...