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Locking Spring Clip for Program Drum Snap Junction

IP.com Disclosure Number: IPCOM000079081D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Chrysler, WR: AUTHOR

Abstract

As indicated in Fig. 1, program drum 10, containing precisely oriented rows of optical sense openings 15, is arranged to be driven by motor 20. Shaft 22 of the motor has symmetrical dowel pin extensions 23a,23b, which form a snap fit coupling union with grooves 25a,25b (Fig. 1; 23b,25b hidden) in LEXAN* extension 28 of the drum.

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Locking Spring Clip for Program Drum Snap Junction

As indicated in Fig. 1, program drum 10, containing precisely oriented rows of optical sense openings 15, is arranged to be driven by motor 20. Shaft 22 of the motor has symmetrical dowel pin extensions 23a,23b, which form a snap fit coupling union with grooves 25a,25b (Fig. 1; 23b,25b hidden) in LEXAN* extension 28 of the drum.

A problem in this respect is that the snap fit must secure positioning of the drum to a tight schedule of tolerances. However the drum itself may be frequently coupled and decoupled in normal usage, resulting in a tendency for the grooves 25a,25b to quickly become deformed and enlarged beyond limits of acceptable positioning tolerance.

The problem is eliminated by the spring clip 30 (Fig. 2). Clip 30 formed of
0.036 spring steel music wire is snap fitted onto the motor shaft 22 at section 30a (see Fig. 1), and oriented so that loops 30b,30c fit over respective dowel pin extensions 23a,23b of shaft 22. Arm extensions 30d,30e on the wire are situated parallel to the dowel pins in a plane slightly offset from the plane perpendicular to shaft 22, Which also contains the axis of the dowel pins. Arms 30d,30e are therefore symmetrically captured in grooves 25a,25b; exerting spring forces counteracting the misaligning effects of groove wear. * Trademark of General Electric Company.

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