Patent GB-139306-A (GB)
Title: Improvements in electric printing telegraph machines
IPC: H04L17/22
Filed: 1919-03-07
Abstract: 139,306. Western Electric Co., (Western Electric Co.). March 7, 1919. Electric c type - lever machines. - In a typeprinting telegraph, typelever mechanism is provided on a carriage traversed for letter spacing, and the selecting - mechanism includes stationary selecting- bars extending across the machine in which selection is dependent on sequences of current, for example combination of five impulses, positive or negative, and combination bars for character selection travelling with the type-carriage, the parts being dissociated between successive selections to permit the letter-spacing movement. The selecting-bars also co-operate with stationary combination bars for auxiliary selections such as carriage return, line-spacing, platen shift, and signalling to operator. The movements initiated by the selecting-mechanism are completed by a power shaft in conjunction with spring-actuated levers &c. The power shaft is driven by a spring intermittently wound by a motor, and is released for one revolution by an additional impulse following each group of selecting-impulses. The selecting and printing mechanisms are so related that while one character is being printed the next succeeding character is being selected. Type-lever actions.-Combination bars 40, Figs. 1 and 2, on the type-carriage 10 co-operate with selecting bars 20 - - 24 extending across the machine and normally held up by latches 25 - - 29 withdrawn by the selecting magnets 15 - - 19. The selecting bars do not drop immediately on withdrawal of the latches, but are held up by notched detent members 11 until these have been withdrawn during the rotation of the cam-shaft 48, initiated for one revolution by the additional impulse through a starting magnet 33. A universal bar 41 for restoring the combination bars 40 and holding them in retracted position, and a printing-bar 45 for operating the type-lever connexions, are actuated through extensions 56, 57 of bell-crank levers 58, 59 by a striker-bar 46, which is carried by arms 49, 50 pivoted on a rod 51, and is controlled by cams 47 on the shaft 48, through arms 53 pivoted on the rod 51 and connexions 54 between the arms 53 and members 52 adjustable on the arms 49, 50. When the universal bar 41 is advanced, all the combination bars 40 advance slightly, under the action uf springs 43. The selected bar advances still further until astride of the selecting-bars. An extension 60 on the selected bar then engages a pin 61 on the corresponding type-lever pull-bar 62, bringing this into the path of the printing-bar 45. When the selected pull-bar has been engaged by the printing-bar, the combination bars are restored by the universal bar 41 under the action of the springs 44, and the selecting-bar are restored by upward movement of the members 11 under the action of cams on the shaft 48. The additional impulse following the group of selecting-impulses energizes, in addition to the starting-magnet 33, Fig. 1, an overlap magnet 30, Fig. 4, which controls pivoted stop members 32 co-operating with projections 68 on the latches 25 - - 29. The latches are retained by the members 32 in their withdrawn positions until the magnet 30 is energized, and are then returned by their springs 70 until projections 71, Fig. 2, on them abut against the displaced selecting-bars, preferably immediately after the displacement, in which position the latches remain ready to respond to the next selection if required, or to move under the bars immediately these are restored to their normal position. Letter-spacing mechanism.-A letter-spacing rack 77, Figs. 1 and 2, is carried by arms 76 on a rock-shaft 75. A worm-wheel 84 on a shaft 14 co-operates with the rack 77, and is actuated by means of a ratchet-wheel 81 on the shaft 14 and a pawl 80 on an arm 79 connected to a lever 78 actuated by a cam 82 on the shaft 48. When auxiliary selections, described in the succeeding paragraphs, are being made, the pawl 80 is prevented from engaging the ratchet-wheel 81 by means of a cam surface 189 on an arm 186, which is normally free to be swung aside by the pawl, but is blocked against movement by a lever 185 when the auxiliary selecting-mechanism is in operation. Carriage-releasing arrangements. - Auxiliary combination bars 121 - - 125, Fig. 1, in stationary supports 126 co-operate with the selecting-bars 20 - - 24, a universal bar 133, and a striker-bar 130 associated with the cam-shaft 48. The bar 125 controls release of the letter-spacing rack 77 for return of the carriage by means of a tape 141 and spring. The bar 125 brings a pull-bar 134 connected to the rack 77 into the path of an arm of a bell-crank lever 136 actuated by a cam on the shaft 48. The rack is temporarily held in the depressed position by a locking-member 138 on the shaft 14, which is tripped by a member 142 on the carriage at the end of the return movement. While the rack 77 is depressed, operation of the type-levers is prevented by means of arms 190, Fig. 2, on the rock-shaft 75 on the rack 77, which break the engagement between the members 52, 54 of the connexions for actuating the striker bar 46. Line-spacing mechanism.-The combination bar 124, Fig. 1, controls the pawl 155 of the linespacing ratchet-wheel 148, through a pivoted member 149, a bell-crank lever 151 operated by a cam on the shaft 148, and a pull-bar 146 and connexions 152, 153, 154. Platen-shift mechanism.-The platen frame 167, Figs. 1 and 2, is guided by parallel-motion links 168, 169, and is shifted by means of an arm 165, a pull-bar 163, a cam-operated strikerbar 164, and a rock-shaft 161 provided with an arm 160 for engagement by the combination bar 122, and a second arm 162 for rocking the pullbar 163 into the path of the striker-bar. The pull-bar 163 is locked in the shifted position by means of a pawl engaged by the arm 160, and a member 171 which rotates under the action of a spring 172 until a pawl 173 on it strikes an extension 174 on a cam-operated lever, which is subsequently moved far enough to allow the pawl 173 to engage it, the shift movement having meanwhile been completed. The combination bar 123 controls the return of the platen to the normal position, by release of the pawl from the arm 160, permitting the arm 162 to rotate the member 171 and release the parts 173, 174. Alarms.-A bell, lamp, or other signal circuit is closed at the contacts 181, Fig. 1, by the combination bar 121. Ink-ribbon mechanism.-The ink-ribbon 85, Fig. 1, is vibrated by the letter-spacing cam 82, the arms 79 having an extension 86 engaging a crank arm 87 on a rock-shaft 88, which is provided with arms 89, 90 for raising guide pins 91, 92 depressed by springs 93, 94. Driving-mechanism.-The starting-magnet 33, Figs. 1, 5 and 6, controls a brake band 34 through a toggle 97 and a lever 99, the outer end of which is forked and has fulcrum points 100 resting against cams 110, 111 on the shaft 48. When the magnet 33 is energized, the toggle 97 is moved to the right and the lever 99 swings upward about the points 100, until an adjustable stop nut 193 abuts against the framework 12. The lever then turns about a new fulcrum 194, permitting the return of the toggle 97 under the action of a spring 113, and subsequent movement of the lever 99 about the fulcrum 114, under the action of the cams 110, 111, to tension the brake band and .stop the rotation of the shaft at the end of one revolution. The shaft 48 is driven by a spring 95, which is automatically and intermittently wound up by means of a motor 101 and gear 103, 104. The circuit of the motor is controlled at contacts 108, 109 by means of a nut 106 travelling on a sleeve 107 of the gear 104. Operation of the cam-shaft, except when selecting-impulses are being received, is prevented by a break in the circuit of the starting-magnet at the contacts 195, Fig. 4, closed by withdrawal of any one of the latches 25 - - 29.