Patent GB-143625-A (GB)
Title: Improvements in electric selective signalling
IPC: H04L25/42
Filed: 1919-02-26
Abstract: 143,625. Western Electric Co., (Western Electric Co.). Feb. 26, 1919. Type-printing t e l e - graphs. - The signal impulses of a type-printing telegraph system a r e stored in condensers which are successively connected to line by means of a rotary distributor. A keyboard or perforated-strip trans - mitter may be employed, and switching-means are provided to change from one transmitter to the other. When the keyboard transmitter is in use, a lock-out magnet is provided to prevent the repetition of the character impulses if a key is depressed for an interval longer than that of the rotation of the distributor arm. After the condensers have been selectively charged, they are disconnected from the transmitter, in order that a second key may be operated, or the strip advanced to close partly the charging - circuits of the condensers, while the previous character impulses are transmitted to line. A receiving- arrangement comprises two sets of condensers one of which is discharged through the selecting-magnets while the other is being charged. The impulses of succeeding characters are of opposite polarity to control the charging of the condenser sets. Transmitting. - To transmit by means of the perforated-strip transmitter S<1>, Fig. 1, the contacts 15 - - 23 are placed in the positions shown to close partly the charging- circuits of the condensers 30 - - 34. The perforated strip is fed between the contacts 10 - - 14 and a contact-plate connected to the charging- battery 53 through the contact 20. Assuming that the strip is perforated under the contacts 10 and 13, that the contact 49 on the arm 45 of the rotary distributor engages the contact segments 48 and 67, and that the switch 87 is closed, the magnet 44 is then energized as follows: battery 53, contact 21, switches 87, 43, magnet 44, switch 47, contact segment 48, contact 49, contact segment 67, to earth. The switches 25 - - 29 are closed to complete the charging-circuits of the condensers 30, 33, and the switch 68 is closed to energize the starting-relay 69 of the distributor. The tongue 72 of the relay 69 is attracted to complete the circuit of the starting-magnet 73, and the tongue 71 is attracted to break the circuit of the magnet 44 at the switch 47, and the relay 69 is locked up over lead a and contact 49 of the distributor until, with the release of the arm 45 by the energization of the magnet 73, the contact 49 leaves the segment 48. The magnet 73 is deenergized to release the latch 74, and the contact segment 65 is connected to the battery 70 through the tongue 72. The engagement of the contact 75 on the arm 45 with the contact segment 66 allows a condenser 88, previously charged, to discharge through the polarized line relay 51, thereby causing disengagement of the tongue 50 and contact 41. A further rotation of the arm 45 causes the condensers 30 - - 34 to be connected to the line relay 51 through the contact segments 60 - - 64. The charged condensers 30, 33 discharge through the relay 51 to cause the engagement of the tongue 50 and contact 41, while the uncharged condensers 31, 32, 34 are charged in the opposite direction from the battery 54 through the relay 51 to separate the tongue 50 and contact 41. Towards the end of rotation of the arm 45, the contact 49 completes the circuit of the magnet 24 from the battery 80 over the contact segment 79. The energization of the magnet 24 completes the discharging-circuits of the condensers 31, 32, 34 at the switches 36, 37, 39, and the charging- circuit of the condenser 88 at the switch 89. The engagement of the contact 75 and the contact segment 65 energizes the line relay 51 from the battery 70 over tongue 72 to close the line circuit at contacts 50, 41. The de-energization of the magnet 44 by the operation of the relay 69 allows the strip to be fed during the transmission of the previously-set-up signal elements, the tape feed being operated by a magnet 77 when the contact segments 67, 76 are bridged by the contact 49. To transmit by the keyboard S, the switches 15. - - 20 are placed in their lower positions, the switch 22 closed, and the switches 21, 23, 87 opened. When a key is depressed, the switches 55 - - 59 are closed selectively to close partly the charging-circuits of the condensers 30 - - 34, and the switch 82 is closed. The closure of the switch 82 energizes the overlap magnet 81 and magnet 44 from the battery 83 over the switches 43, 47 and the contact segments of the distributor. The magnet 47 and relay 69 operate in the manner previously described. While the key is depressed, the magnet 81 locks up over its armature 84, so that, when the distributor contact 49 engages the contact 79 to energize the magnet 24 and the lockout magnet 46, the latter is locked up over the contacts 84, 85 until the key is released, thereby breaking the locking-circuit. The energization of the magnet 46 opens the circuit of the magnet 44 and relay 69 at the switch 43, so that character elements set up by the depression of a key are not repeated if the key is held depressed, since the distributor cannot be started. Receiving. A receiving-apparatus is divided into two parts each of which comprises a set of five condensers adapted to be selectively charged by the operation of the polarized line relay 121. Fig. 2. The current impulses of one character are of one polarity, in order that the condensers 111 - - 115 may be selectively charged; while the current impulses of the succeeding character are of opposite polarity, in order that the condensers 116 - - 120 may be selectively charged. The charging-circuits of the condensers are controlled by brush contacts 124, 125 mounted, together with a brush contact 126, upon the arm of a rotary distributor, and the tongue 123 of the relay 121. A brush contact 127, mounted upon a second rotary arm 180 degrees behind the arm of the contacts 124, 125, 126, controls the discharging of the condensers through the selecting-magnets 150 - - 154. The discharging-circuits are also controlled by a set of polarized relays 140 - - 144 controlled by the brush contact 126, which also controls the circuit of the printing-magnet 155. If the current impulses of a character are such that the tongue 123 of the relay 121 engages its right-hand contact when the contact 124 bridges the sector A and the contacts 101, 103, 104, the condensers 111, 113, 114 will be charged as follows: positive pole of divided battery, segment 130, brush 125, segment 128, contacts 101, 103, 104, brush 124, segment A, tongue 123, to negative side of the divided battery. The engagement of brush 126 with segment 135 energizes the polarized relays 140 - - 144 to break the discharging-circuits of the condensers 111 - - 115 at the back contacts of these relays, and partly to complete the discharging-circuits of the condensers 116 - - 120 at their front contacts. The engagement of the brush contact 127 with the segments 129, D completes the discharging- circuits of the previous selectively charged condensers of the set 116 - - 120 through the selecting-magnets 150 - - 154, and the subsequent engagement of the brush 126 with the segments 132, 136 energizes the printing-magnet 155 from the battery 145. After a semi-revolution of the distributor arm, the contact 126 bridges the contact segments 133, 137 to cause the contact-arms of the relays 140 - - 144 to engage their back contacts, the contact 125 by bridging the segments 129, 131 partly closes the charging-circuits of the condensers 116 - - 120, which are selectively charged by the tongue 123 of the relay 121 engaging its left-hand contact, and the segments 128, D are bridged to complete the discharging-circuits of the condensers 111, 113, 114 through the selecting-magnets 150, 152, 153. A further rotation of the arm causes the brush 126 to bridge the contacts 134, 138 to energize the printing-magnet 155.