Patent GB-662167-A (GB)
Title: Improvements in or relating to cross-bar switches for automatic telephone systems
IPC: H01H67/26
Filed: 1949-02-28
Abstract: 662,167. Automatic exchange equipment. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Feb. 28, 1949 [March 3, 1948], No. 5385/49. Class 40 (iv). In a cross-bar switch of the type in which the fixed contact members consist of double wires 2 arranged in plane grids, Fig. 1, in one or more grids the wires in each pair are insulated from one another and have separate connections to a supply conductor. In one embodiment, Fig. 2 (not shown), the invention is applied to a switch of the type described in Specification 647,506. Fig. 3 shows the circuits for a switch in which subscribers' lines are connected to the sets of movable contact members (bridges) and out-going lines to the fixed contact wires. When a subscriber lifts his receiver, a relay (not shown) closes a corresponding contact, say 19, to energize the bar relay 49 associated with the first set of fixed contact wires. This couples the first selecting bar with an armature of a magnet 54, which operates after the bar relay 49 due to a condenser 45, and couples the catches for closing the contacts along the first set of fixed contact wires with the armatures of the bridge relays 28 to 31. The magnet 54 also closes a contact 55 to energize the relevant bridge relay 28 which completes the connection, locks itself at contact 36, and at contact 40 releases the bar relay 49 and the magnet 54. A grid of fixed contact wires 57 to 60, not carrying voice currents, in which the wires of each pair are insulated from one another, has one wire of each pair except the last connected to an auxiliary relay 64, 65, or 66, Fig. 3. Operation of the bridge relay 28 closes a contact 67 to short-circuit the first bar relay 49 and energize the associated auxiliary relay 64, which at contact 48 removes a short-circuit from the second bar relay 50 and at contact 71 prepares a circuit for the second auxiliary relay 65, so that a second calling subscriber is connected to the second set of fixed contact wires, and so on. In an alternative arrangement, Fig. 4 (not shown), the auxiliary relays 64 to 66 are connected to the movable contact members 67 to 69 and each of the bar relays 49 to 52 is connected to both members of its associated pair of fixed contact wires 57 to 60. At the end of the call, when the contact 19 is re-opened, the bridge relay 28 and all the auxiliary relays release so that any subsequent call will once more operate the first bar relay 49. In an exchange system, Fig. 5, each of four switches 73 to 76, as described above, has its outgoing lines divided into two groups such as 83, 84 and connected to the bridges of two further switches 77, 78. In switch 77 one grid. of fixed contact wires has the wires of each pair insulated from one another but connected to the adjacent pairs, Fig. 6. Then when all the sets of fixed contact wires are engaged, as shown, a circuit is completed for a relay 88 which shunts the bar relays, such as 49, 50, Fig. 3, of the channels in switches 73 to 76 leading to the switch 77, so that any subsequent call is routed to the second switch 78. Specification 197,185, [Class 40 (iv)], is referred to.