Title: Printer with non return to home rack shift selection mechanism

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Claims: We claim:

1. A printer having a type element mounted for rotation to present different characters to a print position, a pinion connected to said type element for rotation therewith, a drive device comprising a pair of rack members alternatively positionable to engage diametrically opposite portions of said pinion and means for driving an engaged rack member a measured distance wherein the improvement comprises:

a rack selection and positioning mechanism operatively connected to said racks and shiftable to a first rack select position and a second rack select position;

cyclically operable means for providing forces for moving said rack selection mechanism through an operating motion only at the beginning of each print operation;

first and second follower arms alternatively engageable with said cyclically operable means to shift said rack selection and positioning mechanism to said first or second rack selection positions at the beginning of each print cycle and effective to shift said racks to engage a selected one of said racks with said pinion if the other of said racks is engaged.

2. The printer of claim 1 wherein said rack select mechanism further comprises a single pivotable means comprising said follower arms and pivotable in timed relation to said cyclical means.

3. The printer of claim 1 wherein said cyclically operable means comprises a pair of cams.

4. The printer of claim 3 wherein said cams are axially separated by an interference means to permit pivoting of said pivotable means in timed relation with said cyclically operable means and to prevent pivoting of said pivotable means in timed relation to said cyclically operable means, said two timed relations being different portions of the time of said cyclical operations.

5. The printer of claim 4 further comprising a interlock means comprising an interference member moveable with said rack means and a stop member slideably engageable therewith to prevent shifting movement of said rack with respect to said pinion during rack translation.

Other info:

Inventors: McDaniel, Robert F. (Paris, KY, US)
Schaefer, John O. (Lexington, KY, US)

Application Number: 535406
Filing Date: 1974-12-23
Publication_date: 1976-04-06
Assignee: International Business Machines Corporation (Armonk, NY)
Primary Class(es): 400/161.5 400/161.4, 400/320
Other Classes:
US Patent Ref:

3352398	Nov, 1967	Crutcher et al.	197/16.
3559791	Feb, 1971	Waldenburger	197/55.
3572486	Mar, 1971	Hebel et al.	197/55.
3596745	Aug, 1971	Waldenburger	197/55.
3666070	May, 1972	Schaefer	197/18.
3738471	Jun, 1973	Werff et al.	197/16.
3876053	Apr, 1975	Giolitti et al.	197/18.

Other Refs:
Primary Examiner: Burr, Edgar S.
Assistant Examiner: Rader, R. T.
Attorney: Letson; Laurence R.