GB1139060A - Ribbon feed mechanism - Google Patents

Abstract

1,139,060. Ink-ribbon mechanisms. INTERNATIONAL BUSINESS MACHINES CORP. 12 Dec., 1966 [30 Dec., 1965], No. 55460/66. Heading B6F. An ink ribbon mechanism for a proportional letter spacing typewriter making use of a single use carbon transfer ribbon 12 is provided with a drive which is actuated following typing of a letter to advance the ribbon by an amount corresponding to the width of the letter. The drive comprises a pinion 51 which is driven by the proportional escapement neck 58 through an angular position corresponding to the width of the last printed letter, the pinion 51 being associated with a slidable positioning clutch 37 including a toothed upper clutch member 48 and a serrated lower clutch member 39 which displaces a ribbon feed member 35 towards the feed member actuating finger 36 mounted pivotally on a pin 74 and having a depending lug 73 which engages an arm 72 of a clutch release member 68 when the finger 36 is actuated by cam 76 mounted on the shaft 77 driving a type head carriage through a one revolution clutch (not shown). Lug 73 rocks the cam release member 68 provided with a further arm 70 which through its pin rooks a latch member 64 out of engagement with a lug 66 of a bell-crank 59 which pivots upwardly about its pivot 62 to move its associated pin out of contact with the upper surface of clutch member 39 which is disengaged to permit the finger 36 to engage the angularly displaced ribbon feed member 35 and rotate the latter counterclockwise which drives a shaft 27 through a one-revolution coiled spring clutch 33. Shaft 27 imparts its rotation through gears 25, 24, 23 to a ribbon driving roller 18 which co-operates with a spring-biased roller 17 to advance the ribbon by the increment corresponding to the width of the last printed letter. Ribbon spools.-Carbon transfer ribbon 12 is supplied from a spool 13 which is mounted on a hub 15 of a support plate 14 and after passing through guides and ribbon driving rollers 17, 18 the ribbon is wound temporarily on the hub of a take-up spool 20 formed by a core 42 and bifurcated shanks 91 which are passed through diametrally opposed openings 93 at the roof of the core 92, the hub being larger when the ribbon 12 is wound. Retraction of shanks 91 reduces the diameter of the core and permits removal of waste ribbon by tilting the take-up spool upside down. Tensioning of the take-up spool 20 is effected by a gaiter spring 30 passed about a driving pulley of a larger diameter and a driven pulley 29 of a smaller diameter and fast with the bifurcated shanks, the gaiter spring slipping over the pulley 29 to keep the ribbon 12 under tension.