Patent GB-485026-A (GB)
Title: Electric clockwork apparatus and method of synchronising same
IPC: G04C11/08
Filed: 1937-01-06
Abstract: 485,026. Electric clocks. COMPAGNIE INDUSTRIELLE DE MECANIQUE HORLOGERE. Jan. 6, 1937, No. 445. Convention date, Jan. 6, 1936. [Class 139] A clock has a synchronizing lever 22, actuated by the balance 9, which lever is automatically engaged and disengaged by a synchronizing member 26, eonstantly driven by a synchronous motor 2 winding the mainspring 3, according as the motor is in operation or stopped respectivelv. The member 26, which coacts with a fork 24<1>, 24<2> on lever 22, is mounted on the shaft 28 which is continuously driven by the motor 2. When current fails, the parts are in the position of Fig. 3, but with current energizing the motor 2, the magnetic field of a part 25 of the stator attracts the shaft 28 axially downwards, Fig. 3, against spring 29, so that the synchronizing member 26 coacts with the fork 241, 242 and directly controls the oscillations of the balance. The Specification as open to inspection under Sect. 91 comprises also the following modifications. The hands 1, Fig. 1. (Cancelled), are driven through train 4<1>, 4<2> by synchronous motor 2, which also winds up the spring 3. When current fails, the spring 3 drives the hands through a train 5<1>, 5<2> and a clutch 90 which latter may be in the form shown in Fig. 3 (Cancelled). Whilst the motor 2 is in action, the balance 9 driven by the spring 3 is intermittently locked and unlocked to prevent the auxiliary movement sticking due to thickening of the lubricating oil. For this, a spring 8 which holds and releases the balance 9 is mounted on a lever 6 which is rocked about its pivot 7 by a cam 10 constantly rotated by the motor 2. The lower end 8<1> of the lever is pulled to the right by the magnetic field. of the motor so that this field holds spring 8 against balance 9 and cam 10 rocks the lever 6 to release the balance. When current fails, the spring 11 brings lever 6 to the position shown. The clutch which permits drive by either the motor 2 or spring 3 consists of a sleeve 12, Fig. 3 (Cancelled), fastened to the hand arbor 91 and having ratchet teeth 131, 13<2> which coact with clutch members 15, 17 loose on arbor 91. A wheel 14 on clutch 15 is continuously driven by pinion 18 from the synchronous motor 2 so as to drive the arbor 91 and over-ride the clutch part 17. The latter is rigid with a part 16 having an arm 16<2> which is attracted by the polepiece 2<1> so that its part 16<1> is held away from a ratchet wheel 19 connected to the spring 3. When current fails, spring 16<3> rocks the part 16<1> into engagement with wheel 19, now driven by the mainspring, so that its teeth oscillate parts 16, 17 and drive the arbor 91. In another construction, Figs. 7 and 8 (both Cancelled) (not shown), the mainspring of the auxiliary movement is compressed, whilst the synchronous motor 2 is in operation, so that the auxiliary tends to drive the hands at supersynchronous speed ; this is, however, prevented by the motor 2 whilst the latter is running. This construction forms the subject-matter of Specification 488,065. In the construction shown in Fig. 9 (Cancelled) a threaded rod 50 is driven from the synchronous motor by gears 53, 52 and a nut 51 is driven by the mainspring through gears 54, 55 and rods 56<1>, 56<2> which rotate the nut 51 and allow it to slide along rod 50. If the drives from motor and spring are equal a forked arm 57, coacting with nut 51, is stationary. For any difference, arm 57 is rocked and its sector 58 causes a finger 46 either to press against the hairspring 9<1> or to adjust the regulator of the hairspring. In a modification, Fig. 10 (Cancelled) (not shown), the arrangement of Fig. 9 (Cancelled) is applied to a pendulum. The forked lever 57, Fig. 9 (Cancelled), may control, instead of the mechanical parts 58, 46 an electromagnet device for affecting the hairspring, Fig. 11 (Cancelled) (not shown). Fig. 12 (Cancelled) shows a direct electromagnetic action on the balance wheel 9. The latter has a. piece of magnetic metal 67 attracted by the coil 68 through which flows the motor current. The natural frequency of the balance is a multiple or submultiple of the frequency of the current. This device may also be applied to a pendulum, Fig. 14 (Cancelled) (not shown). The effect of the piece 67 may be increased by having, adjacent the coil 68, a permanent magnet 81<1>, Fig. 13 (Cancelled), the magnetic field of which corresponds to the lines of force developed by the alternating current. This magnet is on an arm 82 pivoted at 81 and held in the position shown, against a spring 84, by a coil 83 as long as the latter is traversed by the alternating current. When current fails, the spring 84 removes the magnet 81<1> so that it does not interfere with the normal action of the balance. Figs. 15 and 16 (both Cancelled) (not shown), illustrate a differential gear for driving the clock hands directly from the synchronous motor. This subject-matter does not appear in the Specification as accepted.