Patent GB-1021027-A (GB)
Title: Typewheel mechanism for printing telegraph apparatus
IPC: H04L17/24
Filed: 1962-12-04
Abstract: 1,021,027. Typewriters &c. TELETYPE CORPORATION. Dec. 4, 1962 [Dec. 14, 1961], No. 45732/62. Heading B6F. Type-wheel actions; type-wheel machines; permutation bar selector mechanism; auxiliary drive mechanism.-A transmitter-receiver telegraph apparatus comprises a type wheel 186, Fig. 2, which is mounted on a supporting shaft 190, Fig. 8, the shaft being rotatable and displaceable axially to bring a selected character into printing position and guided for axial movement by a surrounding cage 191-192, 194, 195 which is rotatable to impart the rotational movement to the shaft and within which cage the shaft is rockable to effect impression of the character selected. When the telegraph operates as a receiver it receives its impulses in a selector mechanism 31, Fig. 3, which actuates a selector magnet 91, whose armature 96 unblocks a start lever 99, and a pin 68 therein co-operating with a slot 67 of an arm 66 of a stop bail 64 urges a projection 103, on the arm 66 to enter an indentation 102 of a start cam 104, whereupon a second arm 65 of the stop bail 64 having an end portion 63 releases a stop projection 62 of a clutch latch lever 73 to effect the operation of a clutch 40 which connects the selector mechanism 31 to the main drive shaft 39 driven via gearing by a motor 37 (Fig. 20, not shown). Adjacent the start cam 104, Fig. 5, there are six selector cams 105, each co-operating with a selector cam lever 109, having a projection 110, Fig. 3, which on centring a low portion of the cam 105 will pivot the lever 109 counterclockwise about a post 93, to permit a push bar lever 114 to engage a shoulder 113 of the cam lever 109. Rotation of the cam 105 will push the push bar 114 downwardly to pivot a code transfer bar 117 anticlockwise about a pivot 95. If the apparatus is used as a transmitter manipulation of the various keys on the keyboard 32 (Fig. 1, not shown) will control the permutative setting of a series of contact springs 545 which in turn will control the supply of current to segments 546, Fig. 2, of the distributer mechanism 33. The distributer through its brush 547 will transmit its permutation code signals to the selector mechanism 31, which will control sequentially through the magnet coil 91, Fig. 3, the setting of the code transfer arms 117. The code transfer bars 117 are guided for vertical movement in a slotted guide plate 119 and have coded notches 135 and projections 136 for selectively controlling the actuation of six function code bars 137, provided adjacent their ends with angularly disposed slots 138 (Fig. 15, not shown), which slide upwardly and to the left under the action of springs 141, on reduced portions 139 formed on posts 120, Fig. 2. The six function code bars 137 (Fig. 15, not shown) in conjunction with slides 164, 165, 166, 183, 184, 185, Fig. 8, respectively control the following functions of the type wheel: 137-0 selection of numerals as distinct from letters on the type wheel; 137-1, 137-2, extent of angular displacement of the type wheel; 137-3 direction of rotation of the type wheel; 137-4, 137-5 axial displacement of the typewheel. The type wheel is mounted on a shaft 190, Fig. 8, which is fixed to a spider plate 191, slidably mounted on three posts 192 forming part of the cage which includes top and bottom plates 195, 194, attached to the posts. The cage is fixed to a bearing ring 193 rotatably mounted in a bearing 196 formed in a casting 145 and the bearing ring 193 is attached to an annular gear 197, which is meshing with a pair of racks 198, 199, Fig. 7. The shaft 190, Fig. 8, is articulated for pivotal movement in directions 284 to a push rod 200 pivotally connected to a lever 201, which is rocked by a main rocker 205 about a pivot post 202, to displace the type wheel axially so that any of the four rows of characters may be presented at a printing station opposite a platen 271, Fig. 2. The axial displacement of the type wheel is controlled by bell crank levers 235, 236, 237 which are selectively rocked anticlockwise by upward separate or joint movement of slides 185 and 184, cooperating with raised function code bars 137-5, 137-4 respectively to arrest the projection 243 of lever 201 against their lower vertical extensions. When all three bell crank levers are rocked anticlockwise simultaneously the type wheel moves to a fourth vertical position presenting the lowermost row of type characters opposite the platen 271. Upward movement of the slide 183 in conjunction with code transfer bar 137-3 pivots a direction controlling lever 239, Fig. 3, to pull downwardly a link 244, which will then engage a tab 247 of a pull bar 245 with a shoulder 249 of the rack 199, Fig. 7, and disengage a tab 248 from a shoulder 250 of the rack 198, to change the direction of rotation of the type wheel from a clockwise to an anticlockwise direction. Upward movement of slides 166, 165 in conjunction with their respective code transfer bars 137, which also lift a slide 167 by engaging its shoulders 270, 271, with their shoulders 269, 268, respectively, results in determining the extent of angular displacement of the type wheel by either of the racks 198, 199 so as to select one of the 16 type characters. The racks come to rest again at any of the slides 167 to 164. Upward movement of the slide 164 disengages the formed-over portions 170 of the slide 164 from the stops 171 on a stop plate 158, Fig. 7, so that the operative rack 198 or 199 displaces a floating guide member 161, for guiding the slides 164 to 167, to the right and a lip 172 engages the rear edge of a portion 160 under the action of a spring 175. This displacement results in the selection of numbers on the type wheel. The racks are restored to the position shown in Fig. 7, by a rack driving lever 206, following an impression. Hammer impression arrangements.-After the type wheel has been positioned a print hammer 293, Fig. 2, which is spring released drives the type wheel against the platen 271. The hammer is mounted on a supporting bail 294, having an integral latch plate 298 with a stud 299, which is engaged by an actuating link 303 pivotally attached to a post 304 mounted on the main rocker 205. When the rocker 205 is oscillated the link 303 will rock the bail 294 anticlockwise, which is latched by a latching edge 307 formed on a latch lever 308, the former entering a latching shoulder 306 on the latch plate 298. As the link 303 is retracted by the main rocker 205, when rocked anticlockwise, a hook 310 on the link 303 will engage the edge 307 to disengage the edge 307 from the shoulder 306 to permit the spring 300 (Fig. 19, not shown) to drive the hammer 293 into impression action. Before impression a printing suppression function code bar 134 will be permitted to rise upwardly thereby to raise its associated slide 182, so that' a projection 311 formed on it may raise a bifurcated bell crank lever 312 to rock a laterally extending latching portion 313 away from the bail 294 to prevent the former from engaging the shoulder 306 on the latching plate 298. When print suppression is called for, the suppression function code bar 134 is not raised and as the latch lever 308 is rocked away from the latch plate 298 the portion 313 engages the shoulder 306 as it is freed by the latching edge 307. Letter-spacing mechanism; type carriages; carriage guides and races.-The typewheel and cage are mounted on a carriage comprising a casting 145, Figs. 2 and 3, supported for transverse movement across the printer on a guide rod 146 and guide plate 147. The guide rod 146 co-operates with grooved guide rollers 151, 154 and flat guide rollers 152, 155 mounted in pairs on opposite sides of the casting 145. These rollers co-operate with a further pair of flat guide rollers 176, 157 which ride upon the edges of the guide plate 147. The casting 145 is attached to an endless toothed belt 460 for driving engagement with a toothed roller 462 mounted on the upper end of a shaft 463. A guide roller 464, Fig. 4, co-operates with the roller 462 to guide the belt 460. The lower end of the shaft 463 is provided with a ratchet wheel 466 driven step-by-step in a clockwise direction, Fig. 5, by a driving pawl 467 and retained in position by a detent pawl 468. Each time a character is printed a letter spacing movement occurs automatically due to the combination received in the selector mechanism 31, whereby the print suppression bar 134 in moving upwards and to the left engages an arm 487 on a lever 476 to rock the lever anticlockwise to move a shoulder 478, formed on the lever, part of the path of the downwardly extending arm 479 on the driving pawl 467. This permits the pawl 467 pivotally attached to a pivotal link 470 to move upwardly to follow resiliently an actuator roller 473, which when rocked downwardly will drive the pawl 467 and link 470 to effect a spacing operation of the type wheel carriage. When the selector mechanism receives a signal calling for a spacing operation other than that following the printing of a character the coding of the function code bars 137 and the print suppression - code bar 134 is such that only the function lever 339 is permitted to rise, whereupon a projection 498, Fig. 13, integral therewith releases a lip 409 formed on a spring urged bell crank lever 500, pivotally mounted on a shaft 413, Fig. 5, and the bell crank lever 500 displaces a link 502 articulated to a bell crank lever 475, to rock the latter in a clockwise direction to move the letter space blocking lever 476 and shoulder 478 thereon part of the path of the driving pawl 467. Carriage-return mechanism.-Upon receipt in the selector mechanism 31 of a carriage return signal when the carrigae is at an intermediate line position the point suppression code bar 134 will not be shifted and a carriage return function lever 337, Figs. 5 and 13, will be permitted to rise by the coding of the function code bars 137, whereupon a carria