Browse Prior Art Database

Ribbon Feed Mechanism

IP.com Disclosure Number: IPCOM000090585D
Original Publication Date: 1969-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Caudill, AH: AUTHOR [+2]

Abstract

The feed increments of a typewriter ribbon feed, like that described in IBM Technical Disclosure Bulletin, Volume 5, No. 12, pages 17 and 18, are made more uniform by varying the effective feed stroke of pawl 10 in response to diameter change of ribbon 11. Ribbon cartridge 12 contains a pair of spools 13 and 14 on which ribbon 11 is alternately wound. Bulged spring 15 is carried by cartridge 12 and assumes either of the positions shown as described in U. S. Patent 3,356,202. Shield 16 is pivotally supported on stud 17 and is engageable by spring 15 through upturned bracket parts 18.

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Ribbon Feed Mechanism

The feed increments of a typewriter ribbon feed, like that described in IBM Technical Disclosure Bulletin, Volume 5, No. 12, pages 17 and 18, are made more uniform by varying the effective feed stroke of pawl 10 in response to diameter change of ribbon 11. Ribbon cartridge 12 contains a pair of spools 13 and 14 on which ribbon 11 is alternately wound. Bulged spring 15 is carried by cartridge 12 and assumes either of the positions shown as described in U. S. Patent 3,356,202. Shield 16 is pivotally supported on stud 17 and is engageable by spring 15 through upturned bracket parts 18.

When takeup spool 13 has a small diameter of ribbon 11 wound on it, oscillation of pawl 10 through bracket 19 rotates takeup spool 13 by an amount of two teeth on ratchet 20. As the diameter of spool 13 increases, the linear feed increases causing excess space between adjacent ribbon impressions. When the diameter of spool 13 increases sufficiently to throw spring 15 over center to its alternate position, spring 15 pivots shield 16 slightly counterclockwise to a position where one tooth of ratchet 20 is covered by arm 16a. Reciprocation of bracket 19 thus causes pawl 10 to engage only one tooth of takeup spool ratchet 20 and thus reduces the angular rotation to reduce the linear ribbon feed.

After all ribbon is exhausted from spool 13, bracket 19 is shifted to engage ratchet 21 associated with spool 14 and the ribbon is rewound on spool 14 in a manner identical t...