Patent GB-917138-A (GB)
Title: Automatic alarm devices
IPC: H04M1/274
Filed: 1958-08-06
Abstract: 917,138. Automatic exchange systems. HEDGES, A. E. May 1, 1959 [Aug. 6, 1958; Sept. 9, 1958; Oct. 21, 1958; Oct. 31, 1958; April 1, 1959], Nos. 25131/58, 28822/58, 33561/58, 34987/58 and 10951/59. Class 40 (4). In an automatic alarm device for use in conjunction with a telephone dial TD, Fig. 1, and of the type including a plunger C spaced from but having its axis parallel with a main shaft A and carried to revolve with the main shaft A whilst being movable into and out of the telephone dial TD, the plunger C is connected to a cam follower N2, Fig. 3, which runs around a cam track on a plate J1 to provide a retracted position of the plunger C but which, for the purpose of dialling a digit, leaves the cam track to move into a hole in the telephone dial TD. On closing an alarm switch, an electric motor K is started and rotates main shaft A, The main shaft A carries with it bracket L and plunger C. At the beginning of this rotation, bracket L engages a pin AN, Fig. 9, and rotates a link AL to move an arm AM off the telephone rest AG of the telephone set. A cap AO engaged on a switch AR moves the switch to connect the telephone set to the telephone line. During the first revolution of shaft A, an arm E, Fig. 1, carrying a pin E1 engages a toothed wheel F mounted on a shaft G and advances wheel F by one tooth pitch. During the second revolution of shaft A wheel F advances a further tooth pitch and a disc H carried by the shaft G is moved so that one of its projections H1, Fig. 6, engages a roller J6 carried by an arm J to move arm J about a pivot J8 and retract a closure member J3, Fig. 3, from an aperture J2 in the cam track. The roller N2 running on the cam track then passes through aperture J2 and plunger C is moved under the influence of spring 0 into hole 9 in the telephone dial. Further rotation of the shaft A causes the dial to be rotated until roller N2 engages a profile plate J4, pushes up a spring flap M and regains its position on the top of plate J1, thus withdrawing the plunger C from hole 9. The roller N2 passes over closure member J3 and runs around the cam track once, during the return of the dial. During succeeding revolutions of the shaft the two further projections H1 on disc H provide for digit 9 to be dialled twice more. Next, roller Pl, Figs. 1,.2, moves off cam face F1 (Fig. 5) on wheel F and (through lever P, link Q and profiled fork member U carrying a spindle V to which is secured a gramophone soundbox G1 gramophone needle G2 is lowered to engage a gramophone record on turntable D. The turntable is rotated by shaft A. The sound from the record is transmitted through tone arm Z to telephone microphone T. After the message has been transmitted, the roller P1 is raised by cam face F1 and the fork member U is moved upwardly to raise needle G2 from the record. The profile of the fork member U is such that spindle V is then slid under gravity from end U4 to end U5, thus returning needle G2 to its original position. The dialling and message are repeated until screw AC, rotated by wheel F, is moved axially @ engage dolly AU and switch off the motor K. A different part of the record disc is reproduced on operation of a solenoid Y which, when energized, changes the position of link W. When the solenoid is not energized the message relates to burglary and when the solenoid is energized the message relates to fire. Specification 917,139 is referred to.