GB432211A - Automatic impulse transmitters - Google Patents

Abstract

432,211. Impulse transmitters. HIRSCHFELDT, H., 11, Lyndhurst Gardens, Hampstead, London. Dec. 21, 1933, No. 35988. [Class 40 (iv)] In an impulse-transmitter in which a member 9 controlling the transmission of impulses at contacts 17 co-operates with a shaped member 15 representing a particular subscriber's complete number, the member 9 is brought intermittently into engagement with the member 15 instead of gliding continuously over it. In the arrangement shown, the rod 9 is reciprocated by a cam on a rotary shaft 2 which also carries a universally-mounted cam 3 controlling the impulse springs 17, the rod 9 being linked to the cam 3 in such a way that when the rod encounters a projection 14 impulses are transmitted but when a depression 16 is engaged the cam 3 is tilted and no longer engages the springs 17. The impulsing elements, Fig. 1, may be mounted in a block 22, Fig. 5, reciprocated by a clockwork-driven worm 23 controlled by a starting lever 27, the shaft 2 being geared to the worm for rotation during the return movement only by a pinion 29 and a pawl 30 engaging a longitudinal slot 28. The members 15 may be bars of L- or T-section, Fig. 8, provided with teeth 16 which may be bent up as required and are preferably arranged in two staggered rows. The bars may be arranged to form a hollow cylinder, Fig. 9, with the teeth projecting inwardly, the cylinder being rotatable by a handle 34 to bring any desired bar into operative position, this rotation being only possible when the starting lever 27 is at normal. A shoe 35 wide enough to bridge the gaps 16 but dropping into a longer depression when all the impulses have been sent controls a short-circuit around the telephone instruments.