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Helical Spring Beam-Tension Device

IP.com Disclosure Number: IPCOM000047700D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Shadwick, DT: AUTHOR

Abstract

In ribbon cartridges, it is desirable to maintain a tension on the supply spool and on the exposed span of ribbon extending outside of the cartridge. Illustrated in the drawing is cartridge 10 providing extending arms 12 supporting a span of ribbon 14. The supply spool 16 is provided with a flange 18 which has formed in its periphery ratchet teeth 20. Pawl member 22 is pivotally supported on a pin-type structure 24 in the cartridge 10. Pawl member 22 includes the pawl 26 and lever arm 28 terminating in a ribbon-engaging guide member 30. Extending outwardly from the pawl assembly 22 is a short post 32 which has forced thereover one end of a coil spring 34.

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Helical Spring Beam-Tension Device

In ribbon cartridges, it is desirable to maintain a tension on the supply spool and on the exposed span of ribbon extending outside of the cartridge. Illustrated in the drawing is cartridge 10 providing extending arms 12 supporting a span of ribbon 14. The supply spool 16 is provided with a flange 18 which has formed in its periphery ratchet teeth 20. Pawl member 22 is pivotally supported on a pin- type structure 24 in the cartridge 10. Pawl member 22 includes the pawl 26 and lever arm 28 terminating in a ribbon-engaging guide member 30. Extending outwardly from the pawl assembly 22 is a short post 32 which has forced thereover one end of a coil spring 34. Coil spring 34 and post 32 are geometrically positioned such that coil spring 34 will be deflected laterally by the cartridge wall 36, thereby providing a spring bias to the pawl assembly 22. The spring bias will then act to engage pawl 26 with ratchet teeth 20, thereby preventing undesired unreeling of ribbon 14. As the tension in ribbon 14 builds in response to the conventional takeup mechanism (not shown), the ribbon will act to pull guide member 30 about the pivot post 24 in a clockwise direction, thereby extracting pawl 26 from ratchet teeth 20 and permitting flange 18 and supply spool 16 to rotate. As the supply spool rotates, ribbon will be fed, thus relieving the tension and allowing guide member 30 to return to its initial position engaging pawl 26 with ratchet teeth...