Patent GB-191225382-A (GB)
Title: Improvements in Printing Telegraph Systems.
IPC: H04L17/00
Filed: 1912-11-05
Granted: 1913-11-05
Abstract: 25,382. Western Electric Co., [Western Electric Co.]. Nov. 5. Electric type-wheel actions.-In a type-printing telegraph system using two line-wires, each key of the transmitter is arranged to energize two of a group of six relays, one of these relays sending a positive or negative current on one or both of the lines until the relay is cut off by a switching-relay, which, after an interval of no current, connects the second of the selected relays to line to send another current on one or both of the lines. At the receiving station, the impulses are received by a set of four polarized relays controlling the circuits of six sets of relay windings. The desired relay is included in both of the sets selected by the impulses and is accordingly energized. The typewheel shaft rotates until an arm on it engages with the armature of the energized relay, thus bringing the required letter to printing position. The type-wheel 142 is rotated from the shaft 141 which is driven by the spring 156. The shaft is normally held by the pawl 183 engaging with the ratchet 172, but, when the starting-relay 276 is energized by the first selecting impulse, a circuit is completed for the starting-magnet 179, which withdraws the pawl 183 and allows the shaft to rotate. The type-wheel is positioned by the arm 171 engaging with the end of the armature 148 of the selected type-magnet. When the second selecting-impulse ceases, a printing - circuit is made including relay 277, upper winding of relay 301, printing-magnet 282, arm 171, and armature 148 to ground. The magnet 282 causes the printing of the selected character, and the armature of the relay 277 breaks the selecting-circuits. The spring 156 is wound by the motor 166, the unwinding of the spring causing the yoke 164 to rotate and complete the circuit of the motor at the contacts 168, 169. Electric case-shift mechanism.-In order to bring the second row of characters on the type-wheel into printing position, the magnet 105 is energized, and for this purpose the relay 45 must be selected. In selecting this relay however another relay is energized, the armature of which short circuits the starting-relay 276 through the conductors 288, 289, thus preventing the release of the type-wheel shaft. When the armature of the relay 45 is attracted, a circuit is made from the battery 384 over the lower winding of relay 285 and armature of relay 45 to ground. When the relay 45 deenergizes, the current from the battery 384 passes over the relay 285, shift-magnet 105, and armatures of relays 46, 41 to ground. The armature 189 of the magnet 105 moves the type-wheel vertically, and the wheel is held in this position until the circuit of the magnet 105 is broken either at the armature of the relay 46, which is provided for changing case only, or of the magnet 41, which is provided to restore the whole apparatus tc a normal position. As only 30 relays can be selected, it is arranged that the same combinations of impulses that select the relay 46 for lowering the type-wheel shall select the Z type-magnet 302. The letter Z occurring on the upper row of type, the magnet 302 is selected only when the type-wheel is in the lower position, and the shift relay 285 being then de-energized, a circuit for the magnet 302 is obtained over the upper armature of the relay 285. Electric letter-spacing and carriage-returning mechanism.-(i) The circuit of the printing-magnet being completed over the upper winding of the relay 301 this relay attracts its armature, thus making a circuit over its lower winding for the spacing-magnet 111. The armature 216 of the magnet 111 carries a pawl 217, which engages with the ratchet-wheel 207. The drum 206 rotates with the ratchet-wheel 207 and by means of the cord 211 moves the paper-carriage 108 one step. The arm 219 on the armature 216 closes the contacts 220, thus short-circuiting and de-energizing the relay 301. To move the carriage for spacing between words the relay 43 is selected, thus energizing the relay 301 by a circuit over the lead 281, magnet 277, upper winding of relay 301, armatures of relays 43 and 41 to ground. The relay 301 attracts its armature, thus energizing the spacing-magnet as before. To return the paper-carriage, the reset relay 41 is energized, thus closing a circuit through battery 294 and reset magnet 112. The armature 221 of this magnet carries a pin 228 which moves the arm 209 out of engagement with the ratchet-wheel 207, thus allowing the drum 206 to return to a zero position under the action of its spring and to return the paper-carriage.