GB749565A - Type bar action - Google Patents

Abstract

749,565. Typewriters. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 23, 1953 [Dec. 26, 1952], No. 35729/53. Class 100 (4). In a power-driven typewriter having type-bar action, normal depression of a key produces a single impression but further depression causes repeated impressions. Normal depression of a key lever 2 acts through an operating lug 30, key ear 31 or an actuating plate 6 to cause a cam 5 tc rotate about a stud 16 and engage with a power roll 20 so that a crank-arm 4 is driven. to actuate the type bar in the usual way. The positive drive of the crank arm 4 continues until a tail piece 21 on the cam 5 engages a control stop 22 and slides along its surface, thus stopping the positive drive so that the type-bar strikes under its own momentum. When the cam 5 disengages from the roll 20 a spring 17 restores it counterclockwise and the ear 31 engages the front edge 37 of the lug 30 to prevent further actuation of the type-bar, the plate 6 being forced to rotate and slide about a pin 23 against the action of a spring 25 which, however, restores the plate 6 as soon as the key bar 2 rises and the lug 30 disengages. The key bars 2 slide in slots 34 of a comb 33, Fig. 2. and their normal depression is stopped by an abutment member 44 sliding on rails 50, 51 and supported by a spring 42. Repeated actuations of a typebar for underscore, spacing or back-spacing, are effected by extra depression of the key-bar against the spring 42 thus positioning a repeat lug 52, Fig. 4, to engage the ear 31 before it contacts the lug 30 as the cam 5 restores, thus providing a force through the plate 6 to again rotate the cam 5 about the pin 16 and thus engage it with the roll 20 for repeated actuation of the type-bar. The repeated actuation continues until the key lever is released.