Patent GB-428384-A (GB)
Title: Improvements in or relating to power operated typewriters
IPC: B41J11/24
Filed: 1933-11-13
Abstract: 428,384. Typewriters. BURROUGHS ADDING MACHINE CO., 6071, 2nd Boulevard, Detroit, Michigan, U.S.A. Nov. 13, 1933, No. 31584. Convention date, April 28. [Class 100 (iv)] Carriage - returning mechanism; margin stops.-The mechanism comprises a carriagereturning key or like member which throws in a clutch to couple the carriage to poweroperated mechanism, the clutch being automatically thrown out, irrespective of the position of the carriage-returning key, when the carriage is arrested; means for returning the carriage to paragraph position, these means being preferably controlled by manipulating the carriage-returning key ; means for cushioning the carriage after it has been disconnected from the returning-mechanism ; means for preventing the carriage from rebounding when arrested; and the provision, in connection with tapes for propelling the carriage in letter-spacing and return directions, of means for keeping taut the inactive tape. The carriage-returning mechanism may be associated with the power-operated linespacing and shift mechanisms described below. In the machine shown rear view in Fig. 2, the carriage-returning and other mechanisms are driven by a small motor 15 housed within typewriter framework of standard size, the employment of projecting or depending parts of the framework or of auxiliary casings being avoided. The framework may be constructed in the manner described in Specification 428,383, the motor being carried by a crosspiece 17 connected to side plates 1, 2, and a finished casing being provided for the side plates and back. The carriage 9 is propelled in letter-spacing and return directions by tapes 32, 45 respectively, wound on a drum 30 which is driven by a coiled spring for letterspacing and by the motor for return. The tape 32 passes over a pulley 33, and a pulley 35 carried by a spring-tensioned slide 36, and is connected to a hook 39 on a plate 40 mounted to slide on studs 41, Fig. 4, on the carriage. The tape 45 passes over a pulley 46 and is connected by a link 51 and spring 54 to the plate 40, the link having a slot 52 engaging a pin 53 on the plate. The spring-arrangements take up slack in the inactive tape. The pulley 46 is carried by an arm 47 pivoted at 34, a spring 49 normally holding the arm in contact with a stop 50. A worm 21 on the motor-shaft drives a shaft 23 provided with a loose pinion 55 which is geared through a pinion 56 to a pinion 57 on the drum 30. A clutch-member 89, Fig. 9, splined on the shaft 23, is movable into engagement with a clutch-member 90 on the pinion 55 by means of an arm 87 on a shaft 86 provided with an arm 85 in connection with a link 77 which is drawn downwards by a spring 78. The link is normally restrained by engagement of a lug 76 thereon with a shoulder 75 on a rocking arm 69. The carriage-returning key-lever 60 rocks a bell-crank 62 carrying a spring-urged dog 65 abutting on a stud 74 on a link 70 which is connected to the arm 69. A normally open contact 92 in circuit with the motor is carried by a spring-urged yoke 99 provided with an insulated end 98 abutting on a lug 97 on the link 70. On depression of the carriagereturning key CR, the link 70 is displaced, the motor is started, the lug 76 is released, the link 77 is drawn downwards, and the pinion 55 is clutched to the shaft 23. The lug 76 releases the dog 65 and holds the arm 69, and the carriage-returning key can be released, effective repeat-operation thereof being prevented. When the pinion 55 is clutched, the drum 30 is rotated by the motor, the tape 45 displaces the link 51, and when the end of the slot 52 engages the pin 53, the plate 40 also is displaced to operate linespacing mechanism described below. When the line-spacing pawl 121, Fig. 2, is arrested, the tape 45 causes the plate 40 to entrain and return the carriage. When the carriage has been returned to initial position, a lug 102, Fig. 10, on an adjustable margin-stop 100 engages a stop 103 and arrests the carriage, rebound being prevented by the tape. Thereupon, the tape 45 depresses slightly the pulley 46, a rocking arm 82 in engagement with the arm 47 raises the link 77, the pinion 55 is declutched, and the escapement mechanism holds the carriage. When the link 77 is raised, the link 70, arm 69, and dog 65 return to normal position. The stop 103 is carried by a releaselever 104. A time fuse 19, Fig. 2, protects the motor if the pinion 55 fails to de-clutch. A dashpot 161, Fig. 4, cushions the carriage and prevents the plate 40 from oscillating on the carriage and thereby effecting repeat operation of the line-spacing mechanism. The dashpot consists of a cylinder 161 mounted on a bracket 163 on the carriage, and a piston 164 connected to a bracket 165 on the plate 40. During the initial movement of the plate, the piston draws air through a ball-valve 167, and if the plate starts to oscillate, the ball-valve closes and the movement is damped. When the carriage is restored to control of the escape ment mechanism, the plate 40 is returned by means of the tape 32, the dashpot causing the plate to return slowly to normal position. If the carriage is obstructed during the return movement, for instance by the operator's hand, the pinion 55 is de-clutched in the above-described manner, and the motor is stopped. For arresting the carriage in an intermediate position, an adjustable paragraph-stop 110, Fig. 10, has a lug 111 for engaging a stop 113 on a lever 112 which is connected by a forked link 114, Fig. 9, and a spring 116 to the key-lever 60. The lugs 111, 102 are in different planes. When the carriage-returning is depressed and held, the stop 113 remains in raised position, and when engaged by the lug 111 initiates declutching of the pinion 55 and stopping of the motor. If the carriage-returning key is again depressed and released, the carriage returns to initial position. Line-spacing mechanism ; line-spacing key actions.-The mechanism is operated automatically when the carriage is returned, and can also be operated by means of the carriage returning key when the carriage has been arrested by the margin or paragraph stop. There may also be provided a key for effecting line-spacing when the carriage is in any position. The mechanism may include means for returning silently the line-spacing pawl. A ratchet-wheel 120, Figs. 2 and 16, on the platen shaft 125 co-operates with a pawl 121 which is pivoted at 122 to a loose disc 124, and is connected by a bell-crank 126, 127 to a frictiondisc 129. The disc 124 is connected by a link 135 to a bell-crank 137 having a pin 139 engaging the sliding plate 40. During initial movement of the plate, the disc 124 is displaced and the friction-disc 129, being slightly retarded, causes the pawl to engage an adjustable linespacing shield 130. On further movement of the disc, the pawl effects line-spacing and is then arrested by a stop 132. On return of the plate 40, the disc 124 is returned, and the pawl is returned silently, the frictiondisc causing the pawl to be rocked out of engagement with the ratchet-wheel and shield. Line-spacing can be also effected by depressing the carriage-returning key CR, Fig. 9, when the carriage has been arrested in initial position by the stop 100, Fig. 10. When the carriage has been arrested in intermediate position by the stop 101, line-spacing can be effected by depressing slowly, or depressing and holding the carriage - returning key. Depression of the carriage-returning key starts the motor and clutches the pinion 55, and immediately afterwards, the motor is stopped and the pinion is de-clutched. A key for effecting line-spacing in any position of the carriage is carried by a lever which engages the keylever 60 and is connected to a toothed rocking- arm adapted to engage a rack on the carriage. On depression of the line-spacing key, the carriage is locked by means of the rocking arm, and the line-spacing mechanism is operated. Relay platen-shift mechanism; shift-key actions.-Depression of the shift-key starts the motor, mechanism driven thereby shifts the platen, the motor is stopped, and the platen remains shifted until the shift-key is released, whereupon the motor is re-started and the platen is restored. In the mechanism shown in Fig. 2, the shift-rail 8 for the platen frame is carried by vertically movable links 173 mounted on bell-cranks 175 which are connected to balancing-springs and co-operate with detents 179 for holding the platen in normal of shift position. A double pawl 190, pivoted on one of the links, is formed with a shoulder 194 and a hook 192 for engaging a ratchet-wheel 196 on a shaft 26 which is geared to the shaft 23 driven by the motor 15. The pawl has pin-and-slot engagement with an arm 202 which is pivoted on a bell-crank 204 on the framework, a pin on the bell-crank being arranged in a fork on the arm. The shift-key lever 210 abuts on the bell-crank and is connected thereto by a spring 208. The motor circuit includes a stationary contact 220, and a movable contact 221 carried by a spring-urged yoke 223. A roller 224 on the yoke engages the end of a lever 226 which is pivoted at 227 to the shift-key lever and is connected by a link 229 to the adjacent bell-crank 175. During initial depression of the shift key, the lever 226 is depressed, the contact 221 is permitted to close, and the motor is started. During this period, the arm 202 is rocked idly, and the pawl is detained by an over-centre spring. On further depression of the shift-key, the arm 202, aided by the over-centre spring, rocks the pawl, the hook 192 is caused to engage the ratchetwheel, and the links 173 are raised to shift the platen. At the end of the movement, the lever 226 opens the contact 221, and the hook moves out of engagement with the ratchet-wheel. On release of the shift-key, the lever 226 permits the contact to close, the pawl is rocked to bring the shoulder 194 into engagement with the ratchet-wheel, and