Patent GB-539192-A (GB)
Title: Improvements relating to carriage-returning mechanism for typewriting machines
IPC: B41J11/24
Filed: 1940-02-27
Abstract: 539,192. Typewriters. ROYAL TYPEWRITER CO., Inc. Feb. 27, 1940, No. 3644. Convention date, March 9, 1939. [Class 100 (iv)] In carriage-returning mechanism comprising driving-connections and a disengageable clutch arranged between a motor and the carriage, disengagement of the clutch is facilitated by means of a brake which acts on the driving-connections on the motor side of the clutch, and serves to retard the motor. In the mechanism shown in Figs. 1, 8 and 12, a motor C is coupled to a shaft 48 provided with a pinion 52 engaging a pinion 72 which is loosely mounted on a stub-shaft 62 and is held in frictional engagement with a clutch-disc 69 by means of a spring-urged sleeve 68. A carriage-returning tape F, wound on a drum D, passes over a guide-pulley 24 and is connected to a lever 238 having pin-and-slot engagement with another lever 243 which is connected by a link 248 to a rock-arm 4 carrying the usual line-spacing pawl 3. An adjustable stop 250 limits movement of the lever 238. The drum D is provided with a coiled spring for taking up slack in the tape when the carriage is returned manually. The drum is provided with a clutch-disc 91 and is mounted on ballbearings on a sleeve 80 which can slide on the shaft 62. The sleeve 80 is connected to a rockarm 81 which is mounted on a shaft 117 and is urged by a spring '129 into engagement with a lug 120 on a spring-urged bell-crank 116 secured to the shaft and normally restrained by a pivoted latch 163. A latch-releasing-arm 150 having a notch engaging the latch is suspended from an arm 146 on a shaft 141 which is coupled to a shaft 136 provided with a carriagereturning key. The bell-crank 116 is coupled by a link 124 to a loose disc 55 arranged between a flange 53 on the shaft 48, and a brake-disc 56 which is constrained by a pin to rotate with the shaft. The disc 56 can be moved axially by means of an axially movable pin 57 to cause the disc 55 to be gripped by friction-surfaces 60. The pin 57 engages an arm 226 on a lever 220 abutting on another lever 217 which is connected by, a link 214 to a lever 206. A dog 212 on the lever 206 is arranged in the path of a bell-crank 190 having an arm 192 in the path of a projection 193 on the margin stop 10. The bell-crank 190 may be connected to the piston 199 of a dashpot H. On depression of the carriagereturning key, the latch 163 is released, a spring 132 depresses the bell-crank 116, an adjustable tappet 127 thereon depresses a plunger 112 and thereby closes the motor-switch, and the arm 81 moves the sleeve 80 axially to bring the clutch-disc 91 into engagement with the clutch-disc 69. Thereupon, the tape F rocks the lever 238 to effect line-spacing and then return the carriage, the latter part of the return movement being cushioned by the dashpot H. Finally, the bell-crank 190 depresses the dog 212, the disc 55 is coupled to the discs 53, 56, the motor is braked to reduce pressure between the clutch-discs 69, 91,. and the link 124 is lifted. Thereupon, the bell-crank 116 is raised and retained by the latch 163, the motor-switch opens, the clutch-disc 91 is disengaged, and the carriage is arrested. On slight rebound of the carriage, pressure of the bell-crank 190 on the' dog 212 is relieved, and the disc 55 is released. The arm 150 is formed with an incline which co-operates with an abutment to move the arm laterally and thereby permit the latch 163 to re-engage the, bell-crank 116 if the carriage-returning key is held down. If the carriage is obstructed, the coupling 68 slips. To permit of return of the carriage to over-margin position, the bell-crank 190 is moved out of the path of the projection 193 and the centre stop 12 is moved out of the path of the margin stop 10. For this purpose, the bell-crank 190 is moved axially on its shaft 188 by means of a forked lever 230 in connection with the usual link 18 for rocking the centrestop on depression of the margin-release or tabular key. When the carriage returns to overmargin position, an adjustable abutment 234a co-operates with the bell-crank 190 to stop the 'motor and disengage the clutch 69, 91. The carriage-returning mechanism can be rendered inoperative by moving a slide 165, Fig. 8, into the path of an arm 130 on the shaft 117. The slide is formed with a finger-piece 171, and a locking notch, for co-operation with a screw 169. A pivoted paper-finger 273, Fig. 1, is provided for preventing a narrow sheet from catching in the mechanism. Damage to the tape is prevented by a trough 269. A large part of the mechanism is mounted on a detachable frame 31 and bracket 175. To facilitate assembly, a block 44, Fig. 8, on the motor-shaft is formed with a recess for engaging a finger 46 on the shaft 48 of the pinion 52. 'The Specification as open to inspection under Sect. 91 describes also a manual line-spacing lever 263. This subject-matter, which does not appear in the Specification as accepted, now forms the subject-matter in Specification 539,222.