GB366607A - Improvements relating to locking and interlocking arrangements for electric circuit closing devices - Google Patents

Abstract

366,607. Keyboard switches. SIEMENS BROS. & CO., Ltd., Caxton House, Tothill Street, and BROOME, J. H., 64, Heathwood Gardens, Charlton, both in London. Nov. 11, 1930, No. 33915. [Class 38 (v).] Interlocked switches.-An arrangement of interlocked key switches for use in signalling &c. systems combines an interlock of the chain or like nature whereby the depression of two keys simultaneously is prevented with a spring- controlled locking plate operative on the depression of any key to prevent the depression of any other key of the series, the locking plate being latched in its displaced position to retain the operated key depressed. The latching detent may be released by an associated electromagnet. As shown in Fig. 1, the keys 1 are mounted on operating rods 2 formed with extensions 4 adapted to co-operate with balls 42 and dumbbell-like spacers 42a so disposed within a tube 41 that on depression of any key the members 42, 42a are forced into close formation so preventing the depression of any other key. The operating rod 2 of each of the key switches has a lateral screw 12 extending into an acute-angled slot 11 formed in a sliding locking-plate 17, the action of the screw 12 on the lower portion of the slot 11 moving the plate 17 to the right against a return spring and causing it to be automatically latched in its displaced position by a pivoted spring- controlled detent 28 engaging a recess in the locking plate. Thus the operated key is retained in its depressed position and the unoperated keys are held positively from operation until the detent 28 is released by an extension 37 of the pivoted armature of a releasing electromagnet 34. Each of the keys, Fig. 3, carries an insulating coned member 3 for operating spring contact sets 15 at one or both sides of the spindle through rollers 16 carried by the movable contact springs and the lower portions 4 of the operating spindles are surrounded by springs 6 for retracting the key switches on their release. Further contact springs such as 45 may be operated by insulating projections attached to the latching detent 28 and to the locking bar 17.