Patent GB-184200-A (GB)
Abstract: 184,200. Baron, H., (Aldendorff, F.). Feb. 2, 1921. Automatic exchange systems.-Relates to systems in which quick-acting call-finders and numerical marking-sets respectively are temporarily employed to control the setting up of connections through slow-acting finders and connectors. In the three-digit system shown in Figs. 13, 14, and 15, each group of 100 lines is served by ten slow-acting finders VI, VII, Fig. 14, and by two or three quick-acting finders I, II, Fig. 13. A quick-acting finder I which has attached itself to a calling line controls an idle slow-acting finder VII, which it has previously appropriated by a hunting switch III, to make connection with the same line and is then released. The control circuits pass through wipers of a switch V, which is common to all the quickacting finders of the group and which attaches itself to an engaged finder. The quick-acting finders can therefore only control the slow-acting finders one at a time, and the possibility of wrong connections due to simultaneous calls is prevented. A group selector VIII, Fig. 14, responds to the first digit and extends the call to an idle connector IX with which an idle marking- set X has been associated by a hunting switch XI. Ten connectors and two or three marking, sets are provided for each group of 100 lines. The marking-set responds to the tens and units digits and applies marking-potential to tens and units guide wires to control successive hunting actions by which the connector is adjusted to the wanted line, after which the marking-set is restored and connected by the switch XI to another idle connector. A switch XII common to all the marking-sets of a group acts like the switch V to permit only one controlling operation at a time so as to prevent the possibility of wrong connections when two calls arrive in the group simultaneously. The finders, group selectors and connectors in this system are power-driven panel switches with ten sets of brushes. In the case of the quick-acting finders, all ten sets of brushes are in action simultaneously, but in the case of the slow-acting finders, group selectors and connectors, a particular set of brushes is picked out by a preliminary rotary movement of the selector shaft. In the two-digit system shown in Figs. 16 and 17, the slow-acting finders B and connectors C<1> are simple rotary switches and a different type of marking-set E is employed. The quick-acting finders D may be relay sets, which make connection instantaneously, but are represented as simple rotary switches. The connectors C<1> are brought on to wanted lines by a single uninterrupted hunting action. The switches G1, G2 serve the same purpose as the switches V, XII in the other system. A further modification of the method of controlling a connector C by a marking-set E is shown in Fig. 18. Construction of panel selectors.. A shaft U, Fig. 2, is rotated by a ratchet e to bring a finger such as g<1> under the lug i<1> of the carriage of a particular set of brushes, and is then raised by energizing a fixed coil O to engage a magnetic clutch P on a power shaft R with an iron strip j attached to the shaft U. The shaft is held in its raised position by a ratchet f, the detent D of which controls a contact for keeping the clutch energized until the detent slips under a ratchet tooth. The selector is restored by continuing the rotation of the shaft U until it regains its normal rotary position, whereupon the detent D drops into a vertical slot of the ratchet f and allows the shaft to fall. When the shaft performs its rotary movement by hunting, it is provided with a projection P1, Fig. 8, for successively closing ten pairs of contact springs. The brush carriages are provided with rollers n<1> which move between vertical guide rods. Stops on these guide rods support the carriages in their normal positions, and are staggered in such a way that the traverses of the different sets of brushes overlap, each set of brushes being capable of engaging twenty sets of terminals. When a brush carriage is lifted, a projection d1, Fig. 5, tilts the next carriage above into an inoperative position. The terminal bank comprises metal strips a<1>, b<1>, c<1>, &c. Fig. 3, clamped between layers of insulation and having lateral extensions turned over to form terminals a, b, c. The selector circuits are not ccnnected to the brushes A, B, C but to vertical strips a<3>, b<3>, c<3>, which are connected by the brushes to a selected set of terminals a, b, c. Operaticn of the quick-acting call-finders I, II, Fig. 13. The line relay 7 of a calling line energizes the power magnets P1, P5 of idle quickacting switches to raise the brushes A - - D, A1 - - D1, &c. All the brush-sets of each switch sweep over their terminals so that any calling line is found in not more than ten steps. To prevent two switches from reaching the calling line simultaneously, the brushes of each are arranged a step in advance of the next. When the brush C1 arrives on the terminal of the calling line, the cut-off relay 9 is energized in series with a test relay 45 individual to that set of brushes. The relay 45 locks itself through a part of its winding to the'wire 40, opens the circuits of the power magnet P1 and of the test relays, such as 50, individual to other sets of brushes, and energizes a relay 52. The relay 52 switches the calling line through wires 78, 79 to a relay 100, Fig. 14, in the trunk 82, 83 of the slowacting call finder VII, pre-selected by the switch III, and prepares circuits for controlling the finder VII. The de-energization of the line relay 7 de-energizes a relay 68, which completes at 70 a circuit for the restoring-magnet 73 of the unsuccessful finder II. Operation of the slow-acting call-finder VII, Fig. 14. A switch V, Fig. 13, common to the group of 100 calling, lines and having a set of terminals for each quick-acting finder, is set in rotation whenever a call arrives and is brought to rest on the terminals corresponding to the successful finder I by the energization of relay 90 over a contact of relay 52. The rotary magnet 155 of the finder VII is energized in a circuit 141, 110 closed by the relay 112 energized by relay 100. When the switch VII reaches the. correct rotary position for selecting a set of brushes A7 - - D7 corresponding to the brush-set A1 - - D1 of the finder I, the rotary circuit is opened by the energization of relay 144 in a circuit 20, Fig. 13, 35, 85, 144, 154, 161, 64, 18. This circuit, it will be seen, includes a contact. 64 of the relay 52 individual to the brush-set A1 - - D1 and wipers 18, 20 of the switch V which is in a position individual to the finder I. The relay 144 locks itself in a circuit 157, 109. and energizes the power magnet P2 to raise the selected set of brushes. When the brush D7 arrives on the terminal of the calling line, the power circuit is opened by the energization of relay 148 in a circuit 109, 146, 148, D7, 6, D1, 62, 19. It will be seen that this stopping circuit, like the stopping-circuit for the rotary motion, includes a wiper of the switch V, which has been adjusted to select circuits individual to the finder I, so that it is impossible, in the case of two simultaneous calls, for the switch VII to set itself to any position except that of the calling line discovered by the finder I. The relay 148 locks itself through its right-hand winding and brush C. in series with the cut-off relay 9. The calling line has now been extended to the trunk 82, 83 independently of the finder I. Release of the quick-acting finder I and operation of the switch III to connect it to a free connecting circuit. The relay 148 also closes a circuit over wire 84 to energize relay 37, which energizes a relay 26, which locks itself up and closes a circuit for hunting the switch III. When this switch arrives on the terminals of a free connecting circuit, a relay 140 is energized over contacts 111, 147, wire 81, and wiper 32 and closes a circuit over wire 80 and wiper 31 to energize a relay 27, which unlocks the relay 26, which marks the wire 80 with a non-selectable potential. Operation of the group selector VIII, Fig. 14. In response to the first interruption of the series representing the hundreds digit the line relay 100 removes a short-circuit from a relay 114, which becomes energized and remains energized as long as the impulses continue. Each interruption also momentarily short-circuits the release relay 112 but without effect. The impulses are repeated over contacts 121, 116 to the rotary magnet 172 in parallel with a self-locking relay 123, and on their termination the relapse of relay 114 completes a circuit for the power magnet P3. When the selected brushes A5, B5, C, reach an idle trunk 200, 201, 202 to which a marking- set X has been connected by a switch XI, a relay 125 is energized in a circuit through the brush C5, wire 202, lower winding of relay 250, wiper 244 of switch XI, and wiper 290 of switch XIII in its normal position. The relay 125 opens the power circuit, short-circuits part of its winding to mark the selected trunk non-selectable, and energizes relay 123, which locks and disconnects the line relay 100, connecting the upper trunk wire 83 to ground and the lower trunk wire 82 through the brush B5, wire 201, and wiper 243 to relay 269, which becomes energized and energizes a self-locking relay 268. Operation of the marking-set X, Fig. 15, by the tens and units impulses. During the tens impulses a relay 275 is energized in the same way as the relay 114, so that the impulses are repeated in a circuit 267, 273, 276 to a self-locking relay 282 and to the stepping-magnet 287 of the tens marking switch XIII, the circuit of this magnet being completed over the wiper 290. At the termination of the digit the relapse of the relay 275 energizes a self-locking relay 283, which locks itself up and transfers the impulse circuit through the wiper 28