Browse Prior Art Database

88 Character Case Shift Mechanism

IP.com Disclosure Number: IPCOM000085521D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Abell, WA: AUTHOR

Abstract

A critical aspect of an 88-character barrel cam selection system is the shifting of the rack for a case shift operation at print point. This is the case due to the fact that 90 degree rotation of the head requires 5-1/2 units of barrel cam motion, where each unit is approximately 0.072. This means that the cam follower, which shifts the rack for case shift, must be coupled in with only 0.036 motion of the barrel cam due to the 1/2 unit. In order to provide enough clearance to insure that the rack would not try to switch when 5 units are selected, would mean that the follower would have a bite with the cam of from 0.020 to 0.025.

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88 Character Case Shift Mechanism

A critical aspect of an 88-character barrel cam selection system is the shifting of the rack for a case shift operation at print point. This is the case due to the fact that 90 degree rotation of the head requires 5-1/2 units of barrel cam motion, where each unit is approximately 0.072. This means that the cam follower, which shifts the rack for case shift, must be coupled in with only 0.036 motion of the barrel cam due to the 1/2 unit. In order to provide enough clearance to insure that the rack would not try to switch when 5 units are selected, would mean that the follower would have a bite with the cam of from
0.020 to 0.025.

A method which is the subject of this description would be to use the motion of the 5-1/2 unit pin to couple in the follower to the rack shift mechanism. This could be accomplished by a mechanism such as the one in the attached illustration.

The case shift follower 10 would engage a cam on the left end of the barrel cam 16 as soon as the cam translated an amount equivalent to 5 units of rotation. The rack 26 would not switch, however, because the case shift follower is not connected to the rack shift yoke 12.

When a case shift operation is desired, the 5-1/2 unit pin 14 would be dropped into the cam 16 to obtain the 90 degree rotation. It would also allow rotation of the coupling bell crank 18 and coupling lever 20, so that the coupling shaft 22 would be pushed into engagement with the coupling surface 24...