Patent GB-491352-A (GB)
Title: Improvements in or relating to selecting and typing means for printing telegraphs
IPC: H04L17/26
Filed: 1937-08-20
Abstract: 491,352. Type-printing telegraphy. STANDARD TELEPHONES & CABLES, Ltd. (Adams, A. H.) Aug. 20, 1937, No. 22898. [Class 40 (iii)] [Also in Group XVI] In page-printing apparatus, a type carrier is mounted on a movable carriage and is selectively positioned, to present different types for printing, by a flexible non-extensible tape selective movement of which is effected by members carried on a stationary portion of the, apparatus. In one arrangement, the types are carried by movable or flexible radial members on a rotary carrier and printing is effected by a hammer in a position enabling the line and last character to be read, the tape being controlled by pulleys on levers set in accordance with the code. The types are in a single row and shift is effected by an additional rotation of the carrier through 180 by an additional pulley set by the shift code. In a modification, the types are arranged in rows in a rectangular frame which is given two co-ordinate movement by two tapes controlled by different elements of the code. Type-carrier and printing hammer. The body 10, Fig. 3, of the rotary carrier is mounted on a stud 6 in boss 9 of a frame 5 which also carries printing cam 112 and lever 109 and slides on transverse rails 4, the body 10 being connected to boss 9 by a torsion spring 17. The types 21 have radial stems 22 which are Z-shaped at their inner ends and engage slots in a disc 20, the stems being held between the disc and the face of the carrier by spring 26. The slots in the disc for alternate type stems are arranged on different radii to avoid weakening the disc which is positioned rotarily on the body by radial slots 19, Fig. 1, and pins 18. The printing cam 112 slides on a transverse, shaft 115 driven from the main shaft 85, Fig. 1, and the upper end of printing lever 109 has a pin and slot connection with the hammer 28 which is relatively heavy and carries beneath it a centring pin 16 adapted to pass through one of a circular series of holes in the carrier. The hammer is spring-controlled so that it rebounds on striking a type stem, and when a stem is struck the disc 20 carrying the stems is swung towards the platen 1 about a diametrically opposite point against the action of spring 26, the unstruck types being left behind mainly by inertia. The position of struck type is indicated at P in Fig. 1 and this permits visibility of the line so far printed. In the modified carrier shown in Fig. 16, the types 21 are carried by a thin steel fingered disc 11A fixed to the carrier body 10A, the fingers being pressed by hammer 28 against a yielding lever 20A so that the types are finally advanced perpendicularly to the paper. A further modification Fig. 13, is described in a subsequent paragraph. Type selection. The 5-unit code is used in the arrangement shown, but the apparatus may be adapted for other codes. The signal elements are distributed mechanically or electrically on the start-stop principle to five magnets 90, Fig. 8, which remain operated until released by opposing windings energized by a switch (not shown) on shaft 85. Each armature 92, carries a coiled spring 100 the free end of which is bent as shown at 101, Figs. 1 and 8, to lie beneath a U-shaped wire member 105 pivoted at the ends of the arms of the U on a channel section bar 66 with the bar of the U passing through slots in the sides of the channel bar 66. The U- bars controlled by the magnets are selectively lifted to engage the notched ends of levers 61 ... 65 controlling an aggregate motion device comprising a flexible tape 14 passing over pulleys operated by the arms. The tape 14 connected at one end to the type carrier passes over a case-shift pulley 29 adjusting pulley 30 and selectively operated pulleys 31 ... 35, its other end being connected to a drum 37 mounted on the carriage and rotated by a spring of approximately twice the power of, and in opposition to, the torsion spring 17 of the type carrier. A modification in which the tape is attached at its ends to diametrically opposite points on the carrier, dispensing with spring drum 37, is described with reference to Fig. 19 (not shown). The spindles of the pulleys 31 ... 35 engage slots in vertical plates fixed to the frame, the slots being of different heights to provide combinations of 1, 2, 4, 8 and 16 units of rotation of the type carrier. The pulley spindles are carried by arms having U -shaped ends 52 to provide the equivalent of a wide bearing on pivots 50 also carrying the levers 61 ... 65, extensions 67 of which operate on the pulley arms when bar 66 is moved to the right by cam 74 on the driving shaft. When the apparatus is normal, the spring drum 37 holds stop 40 against a fixed stop 41 and tape adjusting pulley 30 is adjusted by eccentric 69 so that the type carrier is in the datum position. The phases of the cam 74 and the printing cam 112 are such that cam 74 operates bar 66 and the selected levers to draw some of the tape off drum 37 while centring pin 16 still locks the type carrier. The carrier is then released by withdrawal of the pin 16 by the hammer and is rotated clockwise in Fig. 1 by the superior spring power of the drum 37 until stops 40, 41 come into engagement and the selected pulleys reach the limit of their movement whereupon the pin and hammer are moved forward again to centre the carrier and effect printing. When the bar 66 returns to the left, arms 61 ... 65 follow under the action of springs 76 but springs 81 retain the operated pulley arms in position to prevent slackness of the tape. The springs 81 however yield to the pull of the tape when a fresh selection is made and the type carrier released to take up a new position which may require forward or backward movement of the carrier, the tape being taken up under control of the torsion spring on the carrier in case backward movement is required. Shift and unshift. The shift and unshift bars 135, 136, Fig. 1, are released by pin 141 on bar 66 on moving to the right provided certain combinations of levers 61 ... 65 are operated. The shift bar (behind bar 136) is notched similarly to 136 except in the case of the first notch shown dotted at 145 which permits bar 135 to drop with lever 61 unoperated and the rest operated. Cam surface 158 forces a spring pin 157, carried by lever 148 of shift pulley 29, into a notch 159 in cam follower 150 whereupon pulley lever 148 is swung to the left. As shown, the shift code represents 30 units and pulley 29 is arranged to pull the tape to rotate the type carrier through 31 units. To avoid spinning the type wheel more than halfway in one cycle, it is arranged that the carrier is spun to and locked at 30 (due to normal action of the aggregate motion pulleys) in the cycle on which code shift is initiated, the full movement of pulley 29 occurring during the first portion of the next cycle. There are no types on the carrier at positions corresponding to special operation codes. The pulley lever 148 is held in shift position by a locking arm 162 pivoted to the unshift bar 136, the shift bar 135 being lifted by tumbler 140 on the return stroke of bar 66. By using a small numbered shift code, the above described overlap arrangements may be avoided. The unshift bar 136 released when all levers 61 ... 65 are operated, releases arm 162 and the shift pulley lever which is restored to the unshift position by the pull on the tape. Letter spacing, carriage return and line spacing ; Fig. 4. The carriage 5 is drawn across the platen by tape 166 and pawl and ratchet mechanism 172 actuated by cam 170 on the driving shaft, a gap 173 being formed in the ratchet wheel to prevent overdrive in the absence of a return signal. The return code bar 137 is released in a manner similar to the previously described shift bar, and through link 185 rotates cam lever 186 which depresses dog 183 whereupon the next stroke of the driving pawl 168 rotates cam plate 178 to release the holding pawl 171 and spring drum 175 returns the carriage. The cam plate 178 is held in its two positions of rest by a dead centre spring 179 operating through link 180. When the line starting position is reached, pin 190 on the ratchet wheel restores cam plate 178 to its normal position. The line-space code-bar 138 is connected by link 191, Fig. 1, to a bar 192 which is thereby brought down into engagement with a lever (not shown) oscillated by cam 119, bar 192 being thus reciprocated to step a ratchet drive operating on the platen. Modified type carriers and type selection; Figs. 13 and 15. The type carrier comprises a rectangular grid 300, Fig. 13, containing individually protrudible types 21, or a frame carrying a sheet 302, Fig. 15, of rubber with types 21B fixed therein struck and aligned by a socket ended hammer 28B, strips 301 being provided to prevent adjacent types from touching the paper. The frame 300 slides laterally on bars 304 the ends of which are bent back at rightangles and pivoted to the carriage some distance behind the plane of Fig. 13 to form a parallel motion linkage for vertical movement of frame 300. Two tapes 14<1>, 14<11> are connected to a point 306 on the carriage. Tape 14<11> passes over idler 307, 2 unit pulley 308, 1 unit pulley 309 and shift pulley 316 to a rod 317 sliding in the fixed frame and engaging a vertical slot in the type frame. Tape 14<1> passes over idler 307 4, 2 and 1 unit pulleys 310-312, idlers 313, 314, idler 315 on the carriage and is connected to a bar 304. Tape 14<11> is controlled by pulleys 308, 309 to set the type frame horizontally to one of four positions in the right-hand half of the frame, the shift pulley 316 providing for the left-hand half of the frame, whereas tape 14<1> and pulleys 310-312 set the type frame in one of 8 vertical positions. Vertical and horizontal restoring springs 323, 322 are provided. Ribbon feed. The ribbon 127 passes from spools on the fixed frame over guides 130 .. 133, Figs. 1 and 3, on the carriage so t