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Clutched Planetary Ball Drive System for Inked Ribbons

IP.com Disclosure Number: IPCOM000088293D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 4 page(s) / 118K

Publishing Venue

IBM

Related People

Hart, RG: AUTHOR

Abstract

This drive system provides a self-contained bidirectional drive for inked ribbon R3 (Fig. 1) using a friction planetary drive T (Fig. 3) for a drive in one direction and using a similar friction drive for the engaged by a cam roller H for holding one cam or the other stationary to complete a power train through one or the other of the planetary drives.

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Clutched Planetary Ball Drive System for Inked Ribbons

This drive system provides a self-contained bidirectional drive for inked ribbon R3 (Fig. 1) using a friction planetary drive T (Fig. 3) for a drive in one direction and using a similar friction drive for the engaged by a cam roller H for holding one cam or the other stationary to complete a power train through one or the other of the planetary drives.

The system comprises a base plate P1 and a ribbon cartridge support P2 fixed on the plate P1 in spaced relation thereto. A pair of spindles Q1 and Q2 are fixed on plate P1 and extend through coaxially disposed openings in support P2. A planetary drive T is disposed on each of spindles Q1 and Q2 and each comprises an inner race G1, balls D1, an outer race C1 and fingers D2 (Fig. 2) extending between the races and between the balls D1. Drive gears B1 and B2 are disposed on spindles 0,1 and Q2, respectively, and an elastomeric material layer N is disposed between each of the gears B1 and B2 and the corresponding one of the outer races C1. Couplings E1 and E2, onto which ribbon spools R1 and R2 (Fig. 1) may be removably disposed, are provided on spindles Q1 and Q2, and each of the couplings E1 and E2 is integral with the fingers D2 extending between the balls D1 of the respective planetary drives. The cams F1 and F2 are respectively fixed to the inner races G1 of the respective planetary drives on the same spindles Q1 and Q2.

Gears B1 and B2 mesh together and thus rotate together. Gear B1 is driven through the intermediary of an idle gear A1 from a drive gear A2 driven from any suicable power source.

Cam roller H is fixed on the end of a swing arm K pivotally mounted on stud L, and an over-center spring J is effective on arm K for holding roller H either in contact with cam F1 or cam F2 and particularly with pointed protruding cam portions f with which cams F1 and F2 are formed.

Ribbon spools R1 and R2 are contained in a cartridge S (Fig. 1) adapted to seat on support plate P2, and ribbon R3 is adapted to move from one of the spools R1 and R2 to the other and then back again depending on which of cams F1 and F2 the roller H contacts.

Assuming that roller H is held in contact with cam F1 by spring J, cam roller H prevents cam F1 from rotating due to the obstructing effect of cam roller H with respect to the protruding portion f of cam F1. The illustrated inner race G1, being fixed to cam F1, is thus held from rotation, and outer race C1 is driven from gear B1 through the elastomeric layer N between gear B1 and race C1. Outer race C1 is quite thin, and there are only three of the balls D1; and layer N thus bends outer race C1 sufficiently so that balls D1 are forcefully held in contact with both inner race G1 and also with outer race C1. Therefore, since outer race C1 is driven from gear B1 and inner race G1 is held stationary by cam F1, balls D1 planetate between races G1 and C1 and thus drive coupling E1 by reason of the fingers D2...