Patent GB-755978-A (GB)
Title: Typewriter
IPC: B41J7/64
Filed: 1954-01-15
Abstract: 755,978. Typewriters. INTERNATIONAL BUSINESS MACHINES CORPORATION. Jan. 15, 1954 [Jan. 19, 1953], No. 1232/54. Class 100 (4). Portable type-wheel machines. A portable typewriter comprises a type-member 4 and a print hammer 5 which are together letter-spaced across a stationary paper; the type-member 4 is moved longitudinally and rotatively relative to a " home " position to select a character by means of a plurality of permutation bars of which at least one is connected to the longitudinal selection means and at least one connected to the rotative selection means. The longitudinal selective movement is effected by the contact of the key-levers 33, Fig. 6, with cammed portions 31, 32 of permutation bars 29, 30, which in sliding one way or the other move pulley wheels 21, 22, 27, 28 and so shift a tape 12 connected to the type-member 4; rotative selective movement is simultaneously effected by permutation bars 53, 54, Fig. 10, pulleys 49-52 and a tape 43 which passes round a pulley wheel geared to a shaft 10 on which the type-member 4 is rotatably secured. Hammer-impression arrangements. A printing hammer 5, Fig. 8, mounted for reciprocation in a frame 61 which slides in step with the type-member for letter-spacing, is actuated by a spring when a pulley 101 mounted on the hammer 5 is released by the slackening of a tape 98. This tape extends from a fixed point 99, over fixed pulleys 100, 102 on the hammer frame, the pulley 101, guide pulley 103 and a pulley 104 mounted on a crank 107 connected to the armature of a solenoid 108. The hammer is actuated by the last part of the movement of a key lever which actuates a bail 88, Fig. 6, moves a link 113 and pivots a latch 109 and so allows the crank 107 and pulley 104 to move upwardly by the force of the hammer actuating spring 97. The hammer 5 is restored by pulling on the tape 98 which is done by the pulley 104 upon the operation of the solenoid 108 energized by the closing of contacts 112 on the return action of a key-lever 33. Letter-spacing. With each actuation of a key-lever or space-bar 145, Fig. 10, a ratchet wheel 78 is stepped by a double pawl mechanism to rotate drive pulleys 24, 59, to which the tapes 12, 60 moving the type-head 4 and hammer frame 61 respectively are attached. At the end of a line the type-head 4 and frame 61 are returned by a slide 132 and a tape 134 rotating pulleys 24, 59 in reverse direction. Aligning for impression. Rotational alignment is effected by a star wheel 162, Fig. 8, engaged by a rod 163 moved by lever 165 just before the latch 109 is released. Paper guiding arrangements. The paper 7 is guided by continuous plates 154, 155, Fig. 5 (not shown), towards a pair of feed rollers having an external feed handle. Type-wheels. The type-member 4 is interchangeable and comprises a prismatic element 126, Fig. 9, slidably secured to an interfitting base 38 having a key 124. The element is secured in position by a knurled nut. Ink-ribbon mechanism. An ink-ribbon extends between a spool 140 and a spool 141 which is driven by a tape drive. from drive pulleys during the time the type-member is being returned to the beginning of a line.