GB1222470A - Typewriter - Google Patents

Abstract

1,222,470. Typewriters. INTERNATIONAL BUSINESS MACHINES CORP. 27 Nov., 1969 [6 Dec., 1968], No. 57985/69. Heading B6F. Power operated impression and selection.-A power operated typewriter has a normally engaged releasable coupling in the drive to the impression mechanism, which coupling is disengaged after part rotation when a key other than a character key is operated, so that an impression does not occur. In the particular embodiment, a typewriter employing a truncated spherical type-head is described, a cam (19, Fig. 2) on a shaft 18 causing the type-head to swing for impression. The shaft 18 is driven by a continuously rotating power shaft 15 via a normally disengaged, selectively engageable 180-degree cycle clutch 14, intermediate gears 17, 17d and 17c, and the normally engaged releasable coupling 40. The clutch 14 additionally drives the filter shaft 21 via intermediate gears 17, 17a and 17b. Depression of a character key, e.g. 22, causes its respective code-combination bar or interposer 30 to be reciprocated by the filter shaft 21. Each character code combination bar 30 carries a tab 36 which displaces a print cycle select bail 35. Displacement of the bail 35 causes, via linkages 37, 37a, 37b and 37c, a pivoted bell-crank lever or stop 50 to move to the broken line position illustrated, Fig. 1, so that the coupling 40 completes a rotation and impression takes place. Depression of a non-character key, e.g. line feed key (29, Fig. 3), causes the associated codecombination bar (38) without a tab 36 to be reciprocated by the filter bar 21. This results in the stop 50 remaining in position, so that it contacts a control arm 51 of the coupling 40 after part rotation thereof, whereby the coupling is disengaged and no impression takes place. Line feed (Fig. 3).-The line feed mechanism (60) employs a feed pawl (61) that is engageable with a ratchet (62) connected with the platen (12). Clockwise rotation of a bellcrank (63) brings pawl (61) into engagement with the ratchet to drive it clockwise until the pawl encounters a fixed stop (64). Depression of line space key (29) causes its code combination bar or interposer (38) to move the pawl (61) via linkages and levers (65 to 68). Word spacing (Fig. 4) is under the control of an escapement mechanism (70) which includes a pawl (71) pivotally carried by a stud (73) on the carrier 13, Fig. 1. A torque bar (75), extending across the typewriter engages a downwardly extending tab (76) of the escapement pawl (71). A clock-spring (not illustrated) urges the carrier to the right, motion being resisted by the pawl. A cam (96) on the filter shaft 21 operates via a bell-crank lever (90) and tie rod (95), a trigger assembly (80) which pivots the torque bar (75) about its axis to lift the pawl (71) from the teeth of an escapement rack 77.