GB234036A - Improvements in or relating to impulse transmitters for use in telephone or like systems - Google Patents

Abstract

234,036. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Obergfell, H. F.). May 15, 1924, [Convention date]. Impulse-transmitters of the dial type (shown disassembled in Fig. 1 and in rear view in Fig. 3) comprise the following features : -(1) The complete dial is secured to a telephone instrument by lugs 48, 48<1> on the impulse-spring bracket 80 which is in turn fixed to the base of the cup member 25 by screws 47, 47<1> so that the remainder of the instrument may be readily removed without interfering with the springs. (2) The main shaft 20 is mounted in a single bearing formed in a hub 27 and is held therein by the driving spring 82, Fig. 3, whilst. the finger plate 10 is fixed to a plata 18 on the shaft 20 by a screw 9, the plate 10 thus being removable without disturbing the shaft 20 and the impulse mechanism. The plate 18 carries a driving pawl 35 and is also provided with stops 72, 73 which limit the motion of the dial. (3) The number plate 15 fits into a ledge in the top of cup 25 and is held by spring arms 26, 26<1> hooking over a shoulder 81. (4) The instruction card 7 and celluloid disc 5 are held by a ring 1 carrying spring members 2, 3, 3<1> engaging corresponding holes in the finger plate 10, an inwardly-projecting spring member 4 engaging with notches 6, 8 to determine the relative positioning of discs 5, 7. (5) A plate 44 screwed to the cup member 25 is provided with two projections 29, 29<1> extending upwards through notches 74, 75, one or other projection forming the finger stop 11, whilst the remaining one is cut off, according as a pause between two series of impulses is or is not required. The plate 44 provides the upper bearing for the shaft 59 carrying the impulse cam 55, Fig. 3, the other end of the shaft being supported in an arched bracket 57. The plate 44 also carries a stop 33 co-operating with the stops 72, 73 to limit the motion of the dial. (6) A unit comprising a toothed wheel 24 geared to a worm wheel 71 on the shaft 59 and a ratchet 23 engaged during the return movement by the pawl 35 on the plate 18 is frictionally held between washers 21, 58 so as to prevent the impulse cam from running ahead of the finger plate 10. The return movement of the mechanism is braked just before the normal position is reached by the pawl 35 engaging a resilient stop 30 on the plate 44. (7) With the finger stop 11 in the position shown in Fig. 1, the shaft 20 carries an arm 53 which in the normal position and during the last half-revolution of the shaft 59 holds the impulse springs 39, 40 out of reach of the impulse cam 55, thus rendering the last half-revolution ineffective to generate an impulse. A further arm 51 controls the normally-open shunt springs 36 - - 38. Specifications 135,416 and 226,152 are referred to. The claims in the present Specification relate to the first five features enumerated above. Other features of the impulse transmitter described herein form the subject-matter of a divided Specification 237,290.