Patent GB-330726-A (GB)
Title: Electric timepieces, clocks and alarms with pendula or escapement mechanism
IPC: G04C21/20
Filed: 1929-05-13
Abstract: 330,726. Tisseyre, L. D. J., and Cotnareanu, I. May 13, 1929. Time-alarms.-An electric clock driven by a continuously running motor (Ferraris or Gramme types) has an alarm device (e.g. an electric bell) which is operated by a magnetic circuit or a coil of the motor. The disc or cylinder c of a Ferraris motor rotates between the poles of a magnet d having a ring e on one pole. The spindle f of the disc c through gears g drives a shaft h to which the mainspring is secured. If desired, the mainspring may be omitted, the disc c being geared directly to the clock train. The magnet d has a supplementary pole j with a coil m which, whilst d is energized, attracts the blade l of the alarm device k. The circuit of coil m is completed by a normally closed switch n. A stop s contacts with a cam p to close the circuit of magnet d. This cam p, which is adjustable frictionally by means of a pointer u, is rotated about shaft q once in twelve hours. When a dip r reaches the stop s, the latter meets an insulated part t, breaking the circuit of magnet d, and also opens the switch n. Blade l is therefore released and moves upwards to meet a contact o closing a circuit for magnet d. Thus pole j is energized and de-energized rapidly and the blade l vibrates against bell k. The alarm may be stopped by a switch v. Cam p may have a number of dips r. Contact o may be omitted if the frequency of vibration of blade l is the same as the frequency of the alternating current supply. If desired, the alarm device is operated by a separate magnetic circuit. In a modification the bell circuit is opened and closed by the mechanism of Fig. 3. Wheel 1 together with its face cam is pressed out by spring 2 against a pin 2a on a shaft q, about which shaft the wheel 1 is rotated by the clockwork. A groove 5 in the member 1 engages the forked end 6 of a lever 7 which is pivoted at 8 and carries the pivot 10 of a lever 9. Levers 7 and 9 pivot in planes at right angles. Lever 9 has a sector 11 with toothed or striated surface adapted to engage a pinion 12 driven by the clockwork. The other end 13 of this lever can push back a blade 14 (by bearing on a stop 16 thereon) so that it leaves contact 19 and meets contact 34. Wheel 1 rotates until the dip of the cam reaches pin 2<a>. Lever 7 then pivots in the direction 15 so that the end 13 presses on blade 14 and opens contacts 14, 19. This effects the actuation of the alarm bell. At the same time the sector 11 is engaged with wheel 12 so that lever 9 is rotated in direction A. After a time the end 13 is lowered sufficiently to pass under stop 16 and contacts 14, 19 again close, interrupting the alarm. Subsequently sector 11 passes up beyond reach of pinion 12 and the cam member 1 is pushed back as it continues to rotate by pin 2a whereupon levers 7 and 9 are restored to initial position. Before the alarm ceases automatically, it may be interrupted by depressing a button 20 rigid with lever 9. When the contacts 19, 14 are closed to stop the alarm the vibrations of alarm blade l may be stopped by a lug 22 on blade 14. To avoid daily repetition of the alarm the button 20 may be locked in groove 21. When the Ferraris motor is used to wind up the mainspring it is preferably operated intermittently by using contacts under the control of ratchet mechanism driven by the clockwork.