Patent GB-187247-A (GB)
Title: Improved start-stop printing telegraph system and apparatus therefor
IPC: H04L17/00
Filed: 1921-04-07
Abstract: 187,247. Marks, E. C. R., (Morkrum Co.). April 7, 1921. Type-wheel actions, electric driving-mechanism.-Comprises a start-stop printing telegraph system using a starting element followed by a combination of successive selecting elements and a final spacing interval, in which a start-stop shaft in the receiver has its operative positions spaced at wider angles than those of the startstop transmitter shaft in order that the former shaft may be run at a somewhat greater speed than the latter so as to ensure synchronism by the completion of each revolution of the receiver shaft before the end of the corresponding revolution of the transmitter shaft. The transmitter and receiver shafts at any station are driven by the same motor through independent clutches and gearing so designed that the former runs at a less angular speed than the latter, in the ratio of 12 to 13. The five pins 135, Fig. 13, of the receiver (see below) are given correspondingly a wider angular spacing than the five cam-projections of the transmitter. The motor is contiolled by a ball governor which breaks the motor circuit at a predetermined speed. A shaft 98, Figs. 10, 11 and 12, is geared to a shaft 102, Fig. 11, provided with a start-stop clutch 106, 107, 108, the driven member 106 being of metal and co-operating with parts 107, 108, lined with wood. The receiver trip arm 114 is operated through toggle mechanism 124, Fig. 11, which is adapted to be tripped by the armature 118, Fig. 12 (not shown in Fig. @ of the line magnet 3. The shaft begins to revolve on the receipt of the starting element of each signal, which deenergizes the magnet 3 and allows the trip arm 114 to move to the left under the influence of the spring 68, Fig. 11, which operates the clutch. By the end of the revolution, the toggle 124 and trip arm 114 have been restored by the spring 129, so that rotation is stopped by the cooperation of roller 73 and cam 75. A shuttle 143, Fig. 12, revolves with the shaft 98 and also moves axially in accordance with the signal elements received. As this shuttle rotates, a roller 144 carried by it actuates, or fails to actuate, according to its axial position, a succession of five pins 135, Figs. 11, 12 and 13, which projec through holes in a fixed cam surface 142 so that their right-hand ends, Figs. 11 and 13, stand in hollows in the surface. The roller 144 can enter each hollow so as to actuate the appropriate pin if, when it is passing that pin, the shuttle 143 is permitted to move to the left under the influence of the spring 149. This occurs if the signal element being received at that moment is such as to energize the magnet 3, but if tile magnet is de-energized the finger 152, Fig. 12, on its armature 118 prevents the leftward movement of the shuttle and the corresponding pin 135 is not actuated. The rightward movement of the shuttle are effected by the raised portions of the cam 142, which are of such length as to allow considerable latitude in respect of synchronism between receiver and transmitter. For the purpose of phase correction, the angular setting of the shuttle on the shaft 98 can be adjusted and fixed by clamping screws 146, which attach to the shaft the sleeve 145 on which the shuttle rides. In modifications, the pins 135 may be actuated by an arm on a rotating shuttle moved axially by the direct action of the magnet arma ture; or a rocker pivoted on and rotating wich the shaft 98 may be set by a cam ring carried by the armature so that, when the armature is attracted, the rocker is caused to actuate the appropriate pin 135 by means of its bevelled end. In any case, the five pins 135 are successively actuated or not, according to the five signal elements received, and through five corresponding rockers 134 they actuate five plungers 131 so that the signal is registered by the combination of positions of these plungers, which are retained in their right or left hand positions by jockey springs 138 co-operating with collars 140. Finally, during the spacing interval at the end of a signal, the setting of the plungers 131 is transierred to the seekers 158 (see below), of the printer, ready to be printed during the next revolution. First these seekers, which have just effected the printing of the previous signal, are restored by a cam 170, Fig. 12, rotating with the shaft 98; then those of the plungers 131 which have been moved to the right, with their collars 140 against the rotating stop flange 172, are by the cam 173 swept further to the right. through a gap in the stop flange, so as to set the seekers 158; and finally the plungers 131 are restored by the flange 174 which sweeps them to the left, leaving the signal stored in the setting of the seekers 158. The plungers 131 are rotatably mounted in order to reduce the wear of the collars 140 due to their engagement with the cams 173, 174. The frame parts and the seekers, combiner discs, and certain other members are made of stamped sheet metal. The type-wheel 177, wheel 178 for actuating the printing arm, and combiner discs 153, 154 co-operating with the seekers 158, are all clamped to the start-stop shaft 98, and effect the printing of a letter during the revolution next after that in which the elements corresponding to this letter were received and registered upon the seekers 158. The seekers 158 have trunnions 150 which can slide in their bearings 160, 161, Fig. 12, so that, when selected plungers 131 are forced to the right by the cam 173 (see above), corresponding seekers are moved until their lower ends 158<a>, Fig. 10, are situated over the combiner disc 154, Figs. 11 and 12, the lower ends 158<a> of the remaining seekers being correspondingly situated over the other combiner disc 153. A flange 155 then separates the two sets of seekers, this flangs being suitably cut away to permit of their setting and return. The seekers are of sheet metal and have heads 162, Fig. 10, which engage one another so that they cannot rotate until each of the five lower ends 158<a> is opposite to a notch in the combiner disc over which it lies. When the right combination of notches passes under the seekers, the latter all turn momentarily in a clockwise direction upon their trunnions 159, but are immediately afterwards restored by the continued motion of the discs. They thus permit a momentary rotation about the pivot 167, Fig. 10, of a lever 165 having a head 163 cooperating with the seeker heads 162, and actuated by an adjustable spring 168. This lever acts through a link 190 of adjustable length and a rocker 189 to trip a detent 184 and actuate the printing arm 180 just as the required character on the revolving type-wheel reaches the printing point. Case-shift mechanism.-The type-wheel has two cases of type, which are effective according as the wheel occupies one or the other of two possible positions relative to the shaft 98. For this purpose, the type-wheel is fixed to a hub 205, Figs. 10 and 12, which is capable of two positions on the shaft 98 and is retained in one or other of these by the engagement of an arm 204<a>, which it carries, with a spring-held catch 207 mounted on the wheel 178. The shift is effected on receipt of one of two special signals which bring blank characters on the type-wheel to the printing point, and simultaneously permit the tooth 170 on the printing arm 180 to press in one or other of the two projections 209 of the member 208 pivoted at 208<a>. The rocking of this member moves an arm 204 carried by the hub 205 and so effects the shift. Platen-impression arrangements; letter-spacing mechanism.-The printing arm 180, Fig. 10, is pivoted at 181, and tends to turn counterclockwise under the influence of an adjustable spring 182, but is normally held back by the detent 184. When this detent is tripped, as described above, the arm 180 is released, and its tooth 179 engages one of the notches in the peti. phery of the wheel 178, Figs. 10, 11 and 12, which thereupon turns the arm counter-clockwise with force. The paper strip, which passes over a roller (not seen), pivoted at 193 on the arm 180, is thus pressed against the appropriate type on the type-wheel 177. At the end of the revolution, the arm 180 is restored, past blank portions in the notched wheel 178 and type-wheel 177, by a lever 198 actuated by a roller 199 on the former wheel. The feed of the paper strip is effected by the printing arm 180, Figs. 10 and 11, as in the Baudot apparatus, by means of a holding pawl 200 and a feeding pawl 200<1> co-operating with a ratchet 201 fixed to the feed roller 194, Fig. 11. Spacing is effected by means of a blank character on the type-wheel, and a space has to be signalled to effect the printing of the last character in a message. The location of the feed roller at the side of the printer instead of underneath it permits the characters to be read immediately after they have been printed.