Patent GB-522198-A (GB)
Title: Improvements in or relating to switches of the kind used in automatic telephone systems
IPC: H01H67/12
Filed: 1938-09-06
Abstract: 522,198. Automatic exchange switches. STANDARD TELEPHONES & CABLES, Ltd. (Deakin, G., and Bell Telephone Manufacturing Co. Soc. Anon.). Sept. 6, 1938, Nos. 26052/38 and 3307/39. [Class 40 (iv)] Power-driven switches' have wipers 29 which also engage feed strips passing through the wiper carriage and are provided with casings which co-operate with the panel to enclose the switch completely. The wipers are preferably spaced apartby a distance equal to twice the pitch of the terminal rows and wipe over the odd-numbered rows in one direction of travel and the even-numbered rows in the other. General arrangement. The casing 4 which makes a dust-tight joint with the panel face is held thereto by spring catches 10 which are released by pulling out handles 42, 43, the weight being taken by rods 3. The front cover 12 is transparent or has transparent windows. Connections to the switch are made by spring jack arrangements 7, 37. Shock-absorbing joints 11 or washers are provided between the panel and its supports which may consist of angle irons 117 braced by members 118 at intervals. A power shaft serves two bays of 40 switches each and is mounted on a separate angle member 119. The bays may be double-sided with one side hinged to swing out without disturbing the operation of the switches.  Wiper arrangements. The wipers consist of a slotted part 29 which engages the ends of the terminals and two spring arms 49 the ends of which partially embrace a feed strip 30. The wipers and feed' strips are carried by a part 28 which is spring urged away from the main part of the wiper carriage and engages the panel face by four shoes 33. It has limited transverse movement with respect to the main part so that different sets of terminals are traversed in the go and return movement. It is moved to the respective transverse positions by wedges 34 and is latched at 35. Alternatively the transverse movement may be omitted and a double set of feeders and wipers provided. As a further alternative a double set of feeders may be provided passing through the main part of the wiper carriage, the wipers engaging different ones during the go and return movements. Driving arrangements. The driving shaft which, as shown, is clutched to the power shaft in known manner by a flexible gear wheel has self-centring bearings provided jointly by the casing ends and cover and has a recessed or projecting double worm which acts to drive the wiper carriage, the main part of which co-operates with guide members 14, 15 on the casing walls, to and fro. It is preferably built up from separately moulded sections as described in Specification 522,242, [Group XXIV]. Alternatively a bevel wheel on the switch may be brought into engagement by a magnet with a bevel wheel on the power shaft, the former wheel engaging fixed rubber studs to stop the switch when disengaged from the power shaft. Co-ordinate switch. In a modification, Figs. 10, 11 (not shown), the subsidiary part of the wiper carriage has (say) 10 positions relatively to the main part and is driven to any one of these positions by a subsidiary driving member which is engaged only when the main part is in its home position.