Patent GB-459732-A (GB)
Title: Impulse transmitter
IPC: H04M1/274
Filed: 1935-10-03
Abstract: 459,732. Impulse transmitters. INVENTOR TRUST SOC. ANON., 33, Boulevard Royal, Luxemburg. Oct. 3, 1935, No. 27292. Convention date, Oct. 12, 1934. [Class 40 (iv)] In an impulse transmitter designed to transmit certain multi-digit numbers in response to a single selecting-operation, the generation of impulses is controlled by a rotating member which moves through a complete cycle corresponding to a maximum of ten impulses for each digit and then returns to its original or an equivalent position, the actual number of impulses transmitted being determined by a feeler member which cooperates with a code member having teeth the lengths of which represent the successive digits of a wanted number. Two constructions are described, one serving only for calling the special numbers whilst the other enables a number dial to be used both for dialling single digits in the usual way and for calling by a single operation any one of twenty selected numbers. First construction, Figs. 1, 2. A rotary drum 1 carries internal radially-arranged code members 50 a selected one of which as indicated by a pointer 4 is moved into the path of a feeler 49. The mechanism is started by operating handle 16 to wind spring 15 which then drives through gearing 8, 6 a shaft 5 and this in turn drives through gearing 7, 17, 18, a cylinder 20 at a higher speed. As soon as the cylinder moves, an arm 28, carried on a spring-pressed block 29 and normally resting at the top of a stepped cam surface 25, is freed and the feeler 49 moves into engagement with the first tooth of the selected code member 50. When the arm 28 again engages the cam 25 it rides up it to normal and a number of impulses corresponding to the length of the operative tooth of the code member is transmitted by engagement of stepped teeth 21 with contacts 52, 53. After each rotation of cylinder 20, feeler 49 is moved into line with the next code tooth by a fork 38, Fig. 2, controlled by an arm 44 engaging with a stepped cam 46 on shaft 5. Second construction, Figs. 5, 6, 7, 9. For single digits, the impulse wheel 55 is driven during the return movement of finger plate 75 by engagement of ratchet 79 and pawl 85, the speed being controlled by a regulator 90 coupled to a gear 86 fast with the impulse wheel. The wheel is positively stopped in its normal position by a pair of linked pawls, one engaging a tooth of the wheel and the other, in the normal position of the finger plate, entering a recess in a ring 162. To transmit a complete number, selection is made as before by movement of the finger plate, each central sector of the dial, Fig. 5, bearing the name of a particular subscriber, and an additional ten selections being obtained by means of a semicircular hinged flap 135 controlling through a cam 133 an axial rod 130 whereby one or other of two sets of code members 120, 122 is selected. In this case, however, the finger-stop 94, which is integral with a spring box 95 and a gear 96, must be moved. A pawl engaging ring 112 fixed to box 95 then closes a switch 70, Fig. 6, preparing a short-circuit around the impulse springs 59, 60. The shaft 75 moves, through a one-way coupling 152, 153, a ratchet wheel 138 which, through slotted member 137 engaging projection 129, causes the appropriate code member to be selected. During the return movement of the finger stop, ratchet wheel 100 geared to 96 drives impulse wheel 55 and a cam member 64 through one revolution for each digit to be sent. A feeler member 74 and a contact-controlling member 65 are mounted on a spring-controlled sliding tube 71 so that the feeler is brought into engagement with a tooth of the code member 120, and the member 65 is held in a corresponding position whereby at a particular point in the rotation of wheel 55 and cam 64 it is tilted by the cam to close contacts 68, 69 and prevent the transmission of any further impulses. After each digit a pin 149 on cam 64 acts on pawls 147, 148 to release ratchet 138 (coupled by a pawl to ring 141) by an amount sufficient to bring the next tooth of the code member opposite the feeler. The cam member 64 may have two or more similar cam surfaces so that it only makes a portion of a revolution for each digit.