Patent GB-491755-A (GB)
Title: Automatic impulse emitter for telephonic apparatus
IPC: H04M1/272
Filed: 1937-09-20
Abstract: 491,755. Impulse transmitters. VANHEERSWYNGHELS, J. Sept. 20, 1937, Nos. 25460 and 25461. Convention dates, Sept. 18, 1936 and Aug. 19, 1937. [Class 40 (iv)] In an impulse transmitter adapted to send a complete multi-digit number at one operation and in which the values of the digits are determined by masking varying numbers of contact elements arranged in rows of ten, one row for each digit, the corresponding elements in each row are connected together so that the whole contact field may be formed of ten continuous parallel bars, and the rows are rendered operative in succession by a movable contact assembly. The number may be selected by separate digit sliders 63, Fig. 1, or by inserting a card with appropriate rows of perforations corresponding to a complete number. Detailed construction and operation. The digit-determining bars 101 .. 110 lie on a celluloid sheet having six rows of ten perforations and the digit sliders 63 operate endless insulating ribbons 69 having slots which uncover a varying number of perforations in a row thus exposing the bars to a corresponding number of spring contacts 31. When a number card is used this is inserted in a slot in the apparatus and in the same way exposes a suitable number of perforations in each row. The number card has a trapezoidal form and fits a correspondingly-shaped guide to ensure correct positioning. To prevent interference between the two forms of selection, two switches 21, 22, Fig. 11, are provided, one opened by a card when inserted in a slot and the other closed through a gap in a further insulating ribbon 122 only when a slider 62 has been moved to its lowest position, Fig. 1, in which by a bar attached to chains 148 all the sliders 63 are held in their normal positions. After selection, lever 93 is depressed to wind a spring and to rotate through levers 159, 160 a shaft 155 on which is an arm 99 with a toothed sector engaging a pinion 100. The arm 99 moves with it by means of plate 162, a second arm 94 which drives a shaft 92 to move the carriage 30 for the spring contacts 31 to the starting position. On the return movement sector arm 99 drives an impulse-generating switch 129 and a control switch 128 the latter making one revolution for each digit. The impulse-transmitting circuit between terminals 17, 18 includes switch 21 or 22, switch 129, rail 25, carriage 30, rail 26, and contacts 24<1> and 24<2> of switch 125, the impulse-generating switch being shortcircuited over wiper arm 13 when it is moving over segment 11 between digits and when it engages with such of the contacts 1 .. 10 as are connected to bars at which the corresponding perforations are not masked and are therefore engaged by a contact 31. At the end of each digit, shaft 92 is released one step by means of an escapement to move the carriage 30 into the next digit position. During digit transmission, the instrument terminals 19, 20 are short-circuited over rails 25, 26, carriage 30, and switch 125. Switch 125 operated by knob 61 cuts the apparatus into or out of service as required. Modifications. (1) The segment 11 may be engaged by a second brush arm moving in a parallel plane and the contacts 1 .. 10 may be replaced by pairs of spring contacts directly engaged by the arm 13. The segment 11 and the second brush arm may be further replaced by a rotary cam and the same or a separate cam may be used for impulse generation. (2) The connection of the apparatus into circuit and the short-circuiting of the telephone instruments may be effected by springs controlled by movement of the carriage 30 from its normal position. (3) To permit the transmission of 5- or 6-digit numbers by means of perforated cards, the guide for the cards has a rectangular extension adapted to receive a corresponding extension C D E F, Fig. 13, on a 6-digit card, whilst 5-digit cards terminate at the dotted line B C F G. The Specification as open to inspection under Sect. 91 comprises also a further modification in which the number may be transmitted in two parts, the transmission of the second part being initiated by operation of a knob to release a stop in the gearing on the receipt of an audible signal, and the shortcircuiting of the instruments being suitably modified to permit the signal to be heard at the appropriate time. This subject-matter does not appear in the Specification as accepted.