Browse Prior Art Database

Reversible Platen Indexing Mechanism

IP.com Disclosure Number: IPCOM000094674D
Original Publication Date: 1965-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Miles, GT: AUTHOR

Abstract

This apparatus permits typewriter platen 10 to be indexed i either direction. To incrementally rotate platen 10 clockwise and advance the paper, the typist depresses forward index keybutton 11. When reverse index keybutton 12 is actuated, the paper is removed as platen 10 rotates counterclockwise.

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Reversible Platen Indexing Mechanism

This apparatus permits typewriter platen 10 to be indexed i either direction. To incrementally rotate platen 10 clockwise and advance the paper, the typist depresses forward index keybutton 11. When reverse index keybutton 12 is actuated, the paper is removed as platen 10 rotates counterclockwise.

A Y-shaped index shift lever 14 is pivoted on index input member 15 and is normally biased up and to the right by spring 16. This extends from projecting pin 17 on lever 14 to stud 18 offset to one side of stationary guide plate 19. This has a window-like opening 20. The pull of spring 16 causes slot 21 in the right arm of 14 to engage pin 22 mounted on the right side of pawl driver 23. Driver 23 and pawl carrier 24 are pivotally mounted on pin 25 while index ratchet 26 is connected to platen 10. Double pawl 27 is pivoted to carrier 24 and is engaged by pin 28 projecting from the bottom of driver 23. Leaf spring 29 is carried by double pawl 27 and engages the rear side of ratchet 26 above the pivot point of pawl 27.

When the typist depresses keybutton 11, mechanism is engaged which results i member 15 being moved down as represented by arrow 30. The vertical movement of lever 14 is translated to clockwise movement of driver 23 due to the slot 21 and pi 22 connection. Pin 28 on driver 23 pivots member 27. The friction of spring 29 causes left pawl 31 to engage ratchet 26 and rotate platen 10. Fans type pawl shields 32 and 33 control t...