Patent GB-1032800-A (GB)
Title: Clutch mechanism
IPC: B41J11/24
Filed: 1964-12-18
Abstract: 1,032,800. Typewriters &c. SPERRY RAND CORPORATION. Dec. 18, 1964 [Jan. 2, 1964], No. 51541/64. Heading B6F. [Also in Division F2] The carriage return drive system for an electric typewriter incorporates an opposed plate friction clutch 20 connected by a tape 66 to the carriage rack 28, the clutch being engaged to wind the tape on a reel 70 to effect return movement of the carriage, at. the end of which movement the clutch is automatically disengaged. Clutch constructicn.-A central plate 110 with friction facings is disposed between opposed driven plates 72, 124 connected by axial pins 130 carrying spacing springs 134, the plate 124 being engaged by a loading spring 152 compressed by a screwed flange 154 on an axially movable sleeve 126 mounted on the drive shaft 94. A drive plate 104 is secured to a hub member 100 which is pinned to the shaft 94, and carries a series of axial pins 106 engaging the central plate 110, the members being pressed into engagement by a spring 114 carried by hub member 100, and the driven plate 124 is secured to a flange 142 on sleeve by an axial pin 140, the spring 152 pressing the members together. The clutch is engaged by a yoke 164 and actuating lever 180 moving the sleeve 126 to the right, spring 152 overcoming springs 114, 134 to lock members 77, 110, 124 together, the springs 114, 134 releasing and separating the plates upon disengagement. In order to vary the spacing of plates 72, 124 to compensate for wear, the lower end of lever 180 is connected to yoke 164 by an adjustable eccentric pin 184, Fig. 5, and the plate 110 may be centred between plates 72, 124 by an adjustable screw 210 engaging the reduced end portion 92 of drive-shaft 94 by a ball bearing 214. Carriage-return mechanism.-The driven plate 72 is integral with the reel 70 which is fitted with a coiled winding spring 80 and carries the tape 66 which is attached to the rack 28 through a spring-loaded arm. -60. The rack engages a pinion 44 integral with an escapement wheel 46 operable to allow movement of the rack and carriage in the direction " B." Drive shaft 94 is connected by gearing 258, 260 to the power roller 244 driven by a pulley and belt 254, 256. The clutch control lever 180 is operable by toggle links 192, 198 through a bell-crank lever 216 connected to a key lever 250 through a power cam 242 and linkages 238, 236, 232, 230. Operation.-When the carriage is at the end of its travel in the driven direction " B " with tape 66 unwound from reel 70, or whenever the operator so elects, key lever 250 is depressed to engage cam 242 with power roller 244 to operate linkages 238-230 and thus rotate bell-crank 216 about its shaft 200 to actuate lever 180 and yoke 164 to engage clutch 20. Rotation of reel 70 rewinds tape 66 to return the carriage in the direction "A" to its initial position in which the end of a movable control-shaft 280 engages a second bell-crank 278 connected by a link 270 to bell-crank 216, which is thus operated to release lever 180, disengage clutch 20 and so break the drive. Bell-crank 216 may also be operated by an emergency stop lever 290, and a second tape 300 may be attached to rack 28 for operating the line spacing mechanism.