Patent GB-191217858-A (GB)
Title: Improvements in Automatic Telephone Exchange Switches and Controlling Circuits therefor.
IPC: H01H67/12
Filed: 1912-08-01
Granted: 1913-06-26
Abstract: 17,858. Western Electric Co., [Western Electric Co.]. Aug. 1. Automatic and semi-automatic exchange systems.-A power-driven selector, of the type in which the terminals are arranged in a continuous row comprising several sections served by separate sets of brushes, is provided with means for mechanically selecting a set of brushes and for moving the selected set over the terminals of the corresponding section. The selection and actuation of the brushes is controlled by electro-magnets which bring into action high and low speed lifting-rollers. The invention comprises also an improvement in the controlling-circuits of a selector of this class. Construction of selector. The line terminals of a number of selectors are arranged in vertical rows on a flat panel, corresponding terminals in the different selectors being multipled together horizontally. The panel is divided into five horizontal sections, and each selector has 500 sets of terminals arranged in a single vertical strip, and five sets of brushes for serving the terminals in the different sections. The brushes 29, 30, 31, 32, Figs. 2 and 5, which are connected to the selector circuits by sliding contacts with rods 29', 30', 32', are mounted on carriers 28, which are slidable on an actuating-rod 25, and each brush-carrier has a pivoted finger 48 which can be engaged by a pin 47 on the rod 25 to lock the carrier to the rod. To effect this engagement, the rod 25 must be lifted to bring the pin 47 opposite the finger 48 and then twisted on its axis to introduce the pin into a groove 68, Fig. 14. The vertical distance between the pin 47 and finger 48 is different for the five sets of brushes, so that the selection of a set of brushes is determined by the distance through which the rod 25 is raised before being twisted. A particular set of brushes having been seized in this way, the rod 25 is again lifted to carry them over the corresponding section of terminals. This movement is effected at a higher speed, but when the required tens-group of terminals has been reached the speed is lowered again, and the driving power is finally cut off when the brushes are on the required set, the rod 25 being retained in its lifted position by a detent 39, Fig. 1, engaging a rack 44. For lifting the rod 25, its lower portion is swivelled at 65, Fig. 3, and can be tilted into engagement with either a high - speed roller 51 or a low-speed roller 52 by energizing the magnets 24, 23. The twisting of the rod 25 on its axis is effected by shift and release magnets 45, 46, Fig. 1, which rock an arm 42 embracing the rack 44. These magnets are built of steel, so that the arm 42 is retained by remanent magnetism in either position. The shift magnet 45 twists the rod 25 to lock the pin 47 in the finger 48, while the release magnet - 16 twists it back again so as to unlock these parts and to disengage the rack 44 from the pawl 39, enabling the rod 25 and the selected set of brushes to fall back to their normal position. The rod 25 carries an auxiliary set of brushes 58, 60, &c. which slide over a commutator plate 57 and serve in controlling the selective operations, as described below. Circuit arrangements. Figs. 15 and 16 show circuits for controlling a selector of the above construction by means of an operator's keyboard and sending-set, the system being of the kind in which ' reverting ' impulses are sent back in accordance with the movements of the selector. The circuits are controlled bv sequence switches 22, 110 of the sort described in Specification 20,839/09. The positions in which the sequence-switch contacts are closed are shown by the adjacent numerals, a colon indicating that the contact is closed throughout the intervening positions. Operator's keyboard and registers. The depression of the keys representing the wanted number causes the energization of motormagnets M, M<1>, M<2>, which rotate hundreds. tens, and units registers until their circuits are opened by the cut-off relays 12 &c., energized over contacts of the depressed keys. The starting-key 14 is then depressed to energize a relay 17, which moves the sender sequence switch 22 to its first position, thus energizing a relay 33 which moves the sequence switch 22 to its second position and closes a circuit through the relays 37 and 103. The relay 103 moves the selector sequence switch 110 to its first position. Hundreds selection. The low-speed clutch magnet 146 is now energized over the contact 141 and the front contact 106 of the relay 103, and lifts the shaft 177. As the brush 116 passes over the segments 122 of the commutator, the relay 37, Fig. 15, is intermittently shortcircuited by the grounding of the wire 101 over a circuit including the contacts 102, 123, the brushes 116, 121, and the contact 118, and the escapement 43, controlled by the relay 37 over the contact 41 allows the hundreds register to turn backwards towards normal. When the off-normal contact 130' is opened, the relay 33 de-energizes and advances the sequence switch 22 to its third position. in which the relay 33 is again energized over the contact 541. The relay 103, falling back at the same time as the relay 33, moves the selector sequence switch 110 to its second position and energizes the shift magnet 128 so that the shaft 177 is twisted and locks itself to the selected brushcarriage 179. The relay 103 is energized again over a circuit including the contact 133, the commutator brushes 134, 121, and the contact 118, and energizes the selector sequence switch 110 over the contacts 106, 108 to move it to its third position. The clutch magnet 146 remains energized in series with the relay 103 (over a circuit including the contacts 141, 139, the commutator brushes 121, 134, and the contact 133) until the brush 134 leaves the commutator segment 135, which occurs when the uppermost tooth of the rack 181 comes over the detent 180. The relay 103 and magnet 146 are then de-energized and the selector sequence switch is moved to its fourth position over the contacts 126, 131, and then on to its sixth position over the contacts 106, 108, the relay 103 being energized over the contact 140 Tens selection. The relays 103, 37 are now again energized in series, and the high-speed clutch magnet 150 is energized over the contacts 112'. 106 and lifts the shaft 177. As the tens brush 134 slides over the commutator, the relay 37 is intermittently short-circuited by the grounding of the wire 101 over a circuit including the contacts 102, 133, the brushes 134, 121, and the contacts 139, 106, and the escapement magnet 43', controlled by the relay 37 over the contact 422 allows the tens register to turn backwards towards normal. When the off - normal contact 228 is opened the relays 33. 37, 103 are de-energized, the magnet 150 is open-circuited, and the sequence switches 22, 110 are moved to their fourth and seventh positions respectively. Units selection. In the fourth position of the sender sequence switch, the relay 33 is reenergized over the contact 551 and again closes the circuit of the relays 37, 103. The selector sequence switch is moved to its eighth position over the contacts 108, 106 and the low-speed clutch magnet 146 is brought into circuit and lifts the shaft 177 till the selected brushes are on the terminals of the wanted line. The return to normal of the units register is controlled by the short-circuiting of the relay 37 through the units commutator brush 116, and results in the de-energization of the relays 33, 37, 103 and the advancement of the sender and selector sequence switches to their fifth and ninth positions respectively. It should be noted that the circuits for intermittently grounding the wire 101 during tens and units selection included the front contact of the relay 103. This prevents the relay from being re-energized in case the ' settling back ' of the shaft 177 when the power has been removed should bring the brush 134 or 116 back on to the commutator segment that it had just left. Release. The re-opening of the key 14 de-energizes the relay 17, which advances the sender sequence switch to normal and the selector sequence switch to its tenth position. The release magnet 182 is now energized and twists the shaft 177 so as to free the rack 181 from the detent 180 and to disengage the pin 178 from the brush carriage 179. The brush carriage and shaft drop back to their normal positions, the descent of the shaft being checked by the low-speed clutch-magnet 146, which is intermittently energized in series with a self-interrupting device 190. When the brush 134 comes on to the bottom segment of the commutator it closes a circuit through the sequence switch 110, which moves forward to normal.