Patent GB-555112-A (GB)
Title: Improvements in typewriting machines
IPC: B41J7/30
Filed: 1942-07-30
Abstract: 555,112. Typewriters. ROYAL TYPEWRITER CO., Inc. July 30, 1942, No. 10691. Convention date, Sept. 18, 1941. [Class 100 (iv)] Relay actions.-A power-driven toothed drum is mounted near the front frame wall and in front of and above the type rest and is engaged by actuators intermittently connected to the drum and coupled to the pivoted type bars and the key levers. The key levers 29 are pivoted on a sleeve 17 and carry auxiliary levers 30 on pivots 31, levers 30 being coupled by links 8, 11, 14 and levers 9, 12 with the type bars 4 provided with a head rest 7. Levers 12 have an upstanding arm 25 engaged by teeth 27a on a power-driven drum E carried on a shaft 28 mounted in the main frame A. This drum is released tooth by tooth by an escapement F having a plate 61 which is rocked by a rod 34 coupled to a universal bar assembly G and consisting of side arms 35 rocking on sleeve 17, the arms carrying resilient cushions 43 engaging adjustable eccentric stops 44. The arms 35 carry a pivoted cross-bar 37 engaged by ears 39 on the Key levers 29 and moved out of the path of the ears for manual operation of the type bars by a rock arm 143 on a shaft 136 within sleeve 17, this shaft when rotated also locking each lever 30 to its key lever 29. A modified' form of lever 12 with a spring pawl and adjustable stop is also described for rapid typing. The impact of the type bar 4 may be varied by an eccentric mounting of the shaft 28 of drum E, the adjustment being effected by a knob 104 on a screwed stem 99 so as to rock a bail 93 which carries the shaft 28 and is provided with stops 96, 97 engaging with a stop 98 fixed to frame A. The impact may also be varied by regulating the strength of the spring which drives the drum E and is wound by worm gear 84, shaft 86 and worm gear 88 from an electric motor H, the free end of the spring being attached to a collar carried by the drum and arranged to traverse a nut along the threaded end of the shaft, this nut engaging arms of a control switch so as to open and close the motor circuit. The switch is adjustable so as to vary the points at which the switch is actuated. If two type bars are operated together and collide, they may be released by moving drum E slightly in reverse by a spring pawl 125 pivoted on a handled bar 119. The escapement, Fig. 19, consists of a toothed wheel 45 secured to shaft 28 by a collar 46 which acts as a bearing for the drum. This wheel is engaged in turn by a roller 68 mounted on the plate 61 and by a dog 69 pivoted on a screw which is carried by plate 61 and engages the frame member 50 so as to limit the movement of plate 61 in one direction, a stop ear 77 being also provided on the plate. The dog 69 is engaged by a lever 70 pivoted at 71 to plate 61 and provided with a spring 72. Frame 50 is spring- pivoted at 51 to a bracket 52 carried by the main frame A. When plate 61 is rocked so that roller 68 frees one tooth of wheel 45, dog 69 rocks into the path of the next tooth and is then freed so as to allow the roller to engage that tooth by the return of the bar 35 and rod 34. Specifications 555,113, 555,114 and 555,115 are referred to.