GB545634A - Improvements in or relating to selecting switches for use in automatic telephone or like signalling systems - Google Patents

Abstract

545,634. Automatic exchange switches. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., BAKER, G. T. Dec. 4, 1940, No. 17271. [Class 40 (iv)] A selector for non-numerical or numerical use is given a step-by-step movement in which the motion is rapid between and slow over the contacts with the aid of a cam member and a constantly running shaft driven by an individual or common motor. In the arrangement shown in Fig. 1, the initial operation of the impulse relay 22 removes a catch 20 from a stud 18 on a cam 11 which is then turned by a spring 16 until another stud 23 engages the catch. The release of 22 by a selecting impulse frees this stud and the cam is then forced into engagement with a constantly running disc 10 of hard rubber and rotates until it is stopped by engagement of stud 18 or 23 with the catch 20 according as the impulse has not or has terminated. In rotating, the cam lifts pawl 24 to drive a ratchet-wheel 25. If the switch is to be used for hunting, stop 23 is omitted. In a modification, the pawl is driven by a cam-shaped driving member 10 independently of the roller 11. In a further modification, in which the ratchet-teeth are preferably as shown in Fig. 5, the driving pawl, which is reciprocated as a whole as in the previous arrangement, is provided with a pivoted driving end 33, Fig. 7, this end being controlled by a subsidiary cam 34 so as to engage the ratchet wheel during the driving stroke and to clear it during the return stroke. In another arrangement not described in detail a Geneva stop mechanism is used.