GB256022A - Improvements in step-by-step switching apparatus for telephone systems - Google Patents

Abstract

256,022. Coventry Automatic Telephones, Ltd., and Puckette, C. C. June 29, 1925. Automatic exchange selectors.-The restoring spring of a single-motion rotary step-by-step selector is housed within a recess in the ratchet wheel, the arrangement being such that the tension of the spring can be readily adjused without disassembling. In the construction shown the wiper pairs 5 insulated by washers 42 and bush 43 are clamped by a nut 45 to the ratchet wheel 6 which is made hollow and contains the coiled restoring spring 38, the 'wipers ratchet wheel and spring thus forming a unit. The shaft 40 to which the other end of the spring 38 is fixed is clamped to the frame 1 by a nut 48 and the wiper unit is held on the shaft by a disc 46 and split pin 47. The disc 46 which has a D-shaped hole fitting a corresponding portion of the shaft 40 serves for adjusting the tension of the spring 38, this being effected by rotating the disc 46 and shaft 40 with the nut 48 loosened, the wipers 5 resting at this time in their normal position against a fixed stop. Current is supplied to the wipers by feeder wires resting in grooves in metal wheels 20.