Patent GB-432334-A (GB)
Title: Improvements in impulse transmitters for automatic telephone systems
IPC: H04M1/274
Filed: 1934-11-22
Abstract: 432,334. Impulse transmitters. SERVANTON, J., 72<ter>, Rue Villiers-de-L'Isle-Adam, and CONSAEL, J. M., 21, Rue Pierre-GuÚrin, both in Paris. Nov. 22, 1934, No. 33576. Convention date, Nov. 24, 1933. [Class 40 (iv)] In an impulse-transmitter in which a complete seven-digit number is sent during the movement of impulsing contacts relatively to a set of adjustable bars bearing digit - determining projections,' the movable member carries two sets of impulse contacts each associated with a different set of bars, the operative set being determined by a change-over key (57, Fig. 1) which switches over the connections from one contact set to the other. Each set of bars may comprise seven independently - slidable transverse tubular members 1 each bearing ten projections 7 of lengths corresponding to the ten possible values of a digit so that any desired combination of seven digits may be set up in the path of the corresponding contact-operating pawl 54. Alternatively and as shown, the bars of the second set are arranged parallel to the path of the movable member 27 on the surface of a cylinder 15, each bar bearing seven projections corresponding collectively to a particular subscriber's number. Each tubular bar 1 is set by a projecting handle 10 and is held set in a definite position by a spring 13 engaging a ball which enters recesses 14 in the guide tube 2. The cylinder 15 is set through gearing 20 by means of a pointer 24 which moves a block 22 along a helical screw 19 and is held set in a definite position by a roller 25 carried by a spring strip 26 slidably adjustable on the frame 6. The contact-operating pawls 54 are pivoted on opposite sides of the movable member 27 and are shaped so that they move ineffectively over the projections 7 during the forward movement of the member 27 produced through the gearing 33, 32 when the handle 34 is depressed. During the return movement produced by spring 35 under the control of a governor 37, at each engagement of a projection 7 by a pawl 54 an arm 56 moves a contact pair 50, 51 into the path of a cam 42 which thus produces a number of impulses corresponding to the length of the projection. The cam 42 is driven through gearing 41 comprising a pinion 45 engaging a rack 46 which extends parallel to the shaft 28 and passes freely at both ends through the frame members 5, 6 but is adjustably held by a screw 48 engaging a boss 47. In a modification, shaft 28 is provided with a longitudinal instead of a helical groove, and member 27 and also cam 42 are driven through bevel gearing as the result of the rotation of shaft 28. An adjustable stop 62 may be provided to limit the movement of handle 34 and therefore of member 27 when it is desired to send less than the maximum number of digits. Sector 33 attached to handle 34 controls off-normal contacts 59 through an arm 61 which may also control locking members which engage between bar projections 7 in order to prevent movement of the bars when impulse transmission is in progress. Impulse transmission may be made dependent on the removal of the receiver by providing a locking member 66, Fig. 2, engaging a toothed wheel 65. The complete-number bars 7 may be arranged in a single plane instead of around a cylinder, adjustment of the carrier being then effected by a pinion engaging a linear rack. The Specification as open to inspection under Sect. 91 comprises also another construction, Fig. 16 (Cancelled), in which the pawl-carrying member 107 has limited rotary movement on the screw shaft 108, by reason of projections 85, 87 engaging opposite sides of guide 86, so that during the forward movement pivoted roller 91 is clear of pivoted strip 92 but during the return movement, at each engagement of pawl 89 with a tooth 103, roller 91 by tilting strip 92 causes an impulse to be transmitted at contacts 97. This subject-matter does not appear in the Specification as accepted.