Patent GB-152514-A (GB)
Title: Improvements in printing telegraph systems
IPC: H04L5/16
Filed: 1919-10-10
Abstract: 152,514. Western Electric Co., (Western Electric Co.). Oct. 10, 1919. Type-printing telegraphs.-In a type-printing telegraph system, each station is provided with a line switch so that a receiving operator may signal to the transmitting operator, by opening the line circuit, that he wishes to transmit and simultaneously stop the transmitter at the transmitting station. The apparatus at each station consists of a transmitting arrangement, Fig. 1, comprising a rotary distributor associated with a starting relay 26, a starting magnet 25, and a " break-in " relay 30, a break-in key BK, a line relay 27, an indicator 31, and a release key RK. When the starting magnet 15 is de-energized the starting relay 16 is energized when the arm 12 reaches the starting segment S over the following circuit; battery, lower back-contact of relay 30, upper winding of relay 16, contact 17, latch 15<a>, arm 12, segment 32 to earth. The operation of relay 16 closes a locking circuit for itself over upper contact of relay 33 and lower and front contact of relay 16 and also energizes the starting magnet 15 over the segment S, arm 12, and segment 32 to earth. The latch 15<a> releases the arm 12, and as soon as this arm leaves segment S the magnet 15 is de-energized to release the latch 15<a>. The energization of the relay 16 opens the line circuit L at the contact 16<a>, thereby de-energizing the line relays 27 of the various stations on the line. The de-energization of each relay 27 causes its associated starting relay 26 to be energized from battery over segment 36, arm 22, segment S', relay 26 to earth. The operation of relay 26 closes the circuit of the starting magnet 25 to release its latch 25<a> from the arm 22. The relay 26 is locked up over its lower contact. When the arm 22 leaves the segment S' the locking circuit of the relay 26 is broken, thereby de-energizing the magnet 25 and releasing the latch 25<a>. The transmitting arrangement at the station shown and the receiving arrangements at all the stations now operate to transmit and receive the selecting current impulses. When the arm 12 engages stop segment SP the relay 33 is energized to open the locking circuit of the relay 16, which releases its upper armature to close the line circuit L at the contact 16a to energize the line relays 27. The transmitter is now ready to transmit a second series of code impulses. The receiving distributors operate in synchronism with the transmitting distributor, and since the relays 28 are energized the lower windings of the relays 30 are not energized as the brush passes over the segment B and the relay 30 remains inoperative. If an operator at a receiving station wishes to " break in " he operates his key BK to open the line circuit L at contacts 28, thereby de-energizing the line relays 27 so that when the arms 22 engage the segments B the relays 30 are energized. Locking circuits for the relays 30 at all stations, except the one which wishes to " break in," are made over the contacts 29 and the signal lamps 31. The operation of the relay 30 opens at its lower contact the circuit of the starting relay 16 so that the arm 12 is retained by the latch 15<a>. The relays 30 are released by the operation of release keys RK. In the modification shown in Fig. 2, the operating winding of the " break-in " relay is completed over a segment B of the transmitting distributor in order that the " break-in " signal 31 at the transmitting station only is operated. When a " break-in " key BK at a receiving station is operated the relays 27 are de-energized so that when the arm 12 of the transmitting distributor 12 engages segment B the upper winding of the relay 30 is energized and the relay 30 locks up over a circuit containing the lamp 31. The operation of the relay 30 breaks the circuit, at its upper contact, of the starting relay 16 so that the arm 12 is arrested bv the latch 15<a>. In the further modification shown in Fig. 3 the circuit of the " break-in " relay 30 is controlled by a segment B of the transmitting distributor and a segment B<1> in the receiving distributor which is displaced' angularly relative to the segment B. The arms 12 and 22 of the distributors normally rotate in synchronism. When, however, a key BK is operated the arm 22 is not arrested momentarily at the end of each revolution, since the starting relay 26 is energized over the back contact of the relay 27 when the arm 12 engages the segment S. After a few revolutions the arm 22 engages its segment B<1>, while the arm 12 engages its segment B, thereby energizing the " break-in " relay 30.