GB183438A - Improvements in or relating to telephone systems and apparatus for use therein - Google Patents

Abstract

183,438. Western Electric Co., Ltd., (Assignees of Goodrum, C. L., and Reynolds, J. N.). July 21, 1921, [Convention date]. Automatic exchange systems ; selectors.-Relates to systems in which incoming lines are connected through link circuits to idle outgoing trunks by cross-bar switches. The calling lines 37 - - 42 are divided into groups, the group 37, 38, 39 having access to link circuits L1, L2, while the group 40, 41, 42 has access to link circuits L3, L4, all the link circuits having access to the outgoing trunks 43, 56. Construction of switching- mechanism. Fig. 2 shows two sets of horizontal wires 1, 2, 3, 4 and two sets of vertical wires 5, 6, 7, 8, the latter having sets of spring wires such as 9, 11, 13, 15 and 10, 12, 14, 16, extending between the horizontal wires. The spring wires pass through slots in insulating-members 29, one of which is moved to make the desired contacts between the spring wires and the horizontal wires by the partial rotation of one vertical shaft 19, say, and one horizontal shaft 24, say, by the magnets 17, 22, respectively. The partial rotation of shaft 19 brings a series of spring arms 20, 21, &c. above a series of arms, such as 25, 26 secured to the horizontal shafts. The subsequent partial rotation of shaft 24 by magnet 22 thus causes the spring arm 21 to raise the insulating-member 29 to make connection between the wires 1 - - 4 and 10, 12; 14, 16. The spring arm 21 is held in a notch in the arm 26 so that the magnet 17 may de-energize, the connection being maintained bv magnet 22 only. Circuit connections. When a subscriber 39 removes his receiver, his line relay 44 energizes the vertical magnet 17 associated with the subgroup of lines 39, 42, &c. The magnet 17 rocks its shaft and energizes the vertical magnet 32 or 57 corresponding to the first idle outgoing trunk 43 or 56. Assuming that the trunk 43 is free, the magnet 31 (1) rocks its shaft, (2) locks up dependent on relay 51, (3) energizes the horizontal magnet 22 or 55 corresponding to the first idle link circuit L1 or L2, and (4) energizes a slow-release relay 46, which (1) opens the first energizing circuit of magnet 32, (2) extends the starting circuit to magnet 57, (3) closes a holding circuit for the horizontal magnet 22, and (4) energizes the subscriber's cut-off relay 45, thereby de-energizing the relay 44 and magnet 17. The relay 51 energizes over the calling line and opens the circuit of magnet 32, the connection being maintained by magnet 22 only under control of relays 51, 46. If subscribers 39, 42 in the same " vertical " sub-group call simultaneously, the line relay 59 of line 42 keeps the circuit of magnet 22 open until line 42 has been extended to an idle trunk. Similarly, if subscribers 38, 39 in the same " horizontal " sub-group call simultaneously, confusion due to the simultaneousenergization of magnets 17, 61, 62 is avoided by making the circuit of each magnet dependent on the non-energization of the magnet on its left.