GB220728A - Improvements in or relating to line-spacing mechanism for power-operated typewriters - Google Patents

Abstract

220,728. Brougham, F. J., (Addograph Co.). May 25, 1923. Line - spacing mechanism; driving-mechanism. - In typewriters having a carriage supporting a platen roller and a pawl-and-ratchet line - spacing device therefor, a continuouslyrotating shaft, and mechanism for actuating the line-spacing device in any position of the carriage, are mounted on the main framework, and are adapted to be coupled on depressing a key. The platen roller 61 carries a ratchet-wheel 46 cooperating with the tooth 45 of a pawl 44 pivoted to an arm 43 on a rocking frame 40 pivoted on the carriage 57. A shaft 10, driven continuously by a motor 13, carries fast and loose friction-members 14, 15, the member 15 being controlled by a spring lever 17 which engages a lug on a lever 22 operated by a key-lever 24. A pinion 26 on the member 15 engages a sector'27 connected by a link 32 to an arm 33 on a rock-shaft 34. An arm 36 on the rock-shaft is provided with a roller 38. and an ear 42 engaging a flange on the cross bar 39 of the rocking frame 40. The sector 27 has ears 29 for engaging a rubber stop 30 supported by an arm 31 which can be bent for adjustment. On depressing momentarily the key-lever 24, the disc 15 is coupled, the sector 27 is rocked, and the line-spacing pawl is operated. The disc 15 slips if the key-lever is retained in the depressed position. A spring 54 connected to the arm 33 returns to the normal position the parts operated thereby. A stop 56 is provided for the keylever to limit the pressure on the lever 17. The pawl 44 is guided by a hook 49 formed on a plate 62, Fig. 4, secured to the platen frame 51. The tooth 45 of the pawl normally rests on a masking-plate 50 which is pivoted on the plate 62 and can be set in either of two positions to adjust the line-spacing movement. The masking-plate is retained by means of a spring finger 72 having a. projection 73 adapted to engage either of two holes in the plate 62. A stop 75 limits the movements of the masking-plate. When the pawl is operated, the tooth leaves the masking- plate and is drawn into engagement with the ratchet-wheel by a spring 80. The hook 49 is formed with an incline 76 for jamming the tooth at the end of the line-spacing movement. The platen frame 51 may be connected to the carriage 57 by means of parallel links 52 associated with shift mechanism, preferably that described in Specification 208,767, the member 14 being engaged on opposite faces by the friction-member 15, and a friction-member for operating the shift mechanism. The rocking frame 40 and the bottom links 52 are pivoted coaxially, and the links are parallel to a line drawn from the upper edge of the member 50 to the pivot 47 of the pawl 44, these arrangements preventing the line-spacing mechanism from being affected when the platen is shifted. The fast and loose frictionmembers 14, 15 on the shaft 10 consist of a coned fibre disc, and a metal disc having a coned slit flange 15<a>, Fig. 6, respectively, the disc 14 being scraped and cleaned by the edges of the slits.