Patent GB-439354-A (GB)
Title: Improved means for operating impulse electric clock systems
IPC: G04C13/04
Filed: 1934-05-31
Abstract: 439,354. Electric clocks. F.B.M. GEAR SYNDICATE, Ltd., 15, Victoria Street, Westminster, and TENNISON, A. J., Kingswood, Littleheath Road, Selsdon, South Croydon. May 31, 1934, No. 16273. [Class 139] An impulse clock system of master and secondaries having integrating means for storing impulses missed by the secondaries and including a differential gear, is characterized by the combination with the differential of a plurality of cam discs 31, 34, which are advanced at different rates relatively to a single impulse controlling member 37 and assume a normal zero relationship when the secondaries are in phase with the master clock or are out of phase therewith by exactly twelve hours or a multiple of twelve hours so that after a lapse of impulses corresponding to more than twelve hours or more than a multiple of twelve hours, the cam discs are restored only until they resume the zero relationship for the first time. Pendulum 10 of the master clock is maintained in oscillation by electromagnet 14 and battery 13, the circuit being closed at contacts 15 by a trailing finger 16 on the pendulum. A pawl 42 on this pendulum rotates a count wheel 17 which drives the seconds hand and is rigid with a cam 18 : the latter closes contacts 19 once every half minute to energize a magnet 29 which rotates through one tooth a ratchet 27 rigid with a sun wheel 25 loose on shaft 20. Wheel 25 rotates in the direction of the arrow and carries with it planet wheels 24 on a carrier 23 rigid with shaft 20, so that the latter and a disc 31 rigid with it are rotated slightly. Disc 31 has a notch 35 and there is a notch 36 in a similar disc 34 which is geared to disc 31 so as to move slowly in the ratio 1 : 12. Before the above-mentioned movement a lever 37 lies in the registering notches 35, 36 to open the contacts 39. As soon as parts 25, 20, 31 and 34 move, lever 37 is lifted to the peripheries of the discs 31, 34, and contacts 39 energize a magnet 40 which, through its armature 40<a>, causes the left-hand end of a slide 41 to drop. The pawl 42 meets the notched end of slide 41 and pushes the latter to the right to close contacts 43. Current thereupon flows from the mains supply 44 to secondary clocks 45, in series or parallel, and to magnet 30. The latter rotates a ratchet 28 in the direction of the arrow together with sun wheel 26 rigid therewith. Wheels 28 and 26 have the same teeth as wheels 27 and 26 so that this restores planet carrier 23, shaft 20 and discs 31, 34 by the amount which they were previously moved in the opposite direction by wheel 25. Lever 37 drops into the reregistered notches 35, 36 and contacts 39 open. Upon current failure, or if the master is set forward (e.g. for " summer time ") parts 25, 23, 20, 31, 34 move one step at each closure of contacts 19, but the closures of contacts 39 and 43 have no effect on secondaries 45 and magnet 30. Disc 31 rotates once per hour and disc 34 once per twelve hours, whereby notches 35 and 36 move farther from arm 37 to accumulate the number of impulses which have not been sent to the secondaries. On the resumption of current, until the notches are both back at lever 37 for the first time, contacts 39 remain closed and magnet 40 energized so that every swing of pendulum 10 and its pawl 42 causes contacts 43 to send an impulse to clock 45 and magnet 30. In a modification, Figs. 4 and 5, the differential is embodied in the master clock the sun wheel 25 being driven directly from the pendulum instead of electrically by the magnet 29. The pendulum may be electrically or mechanically driven and directly or indirectly oscillates a shaft 52, Fig. 4, carrying pawls 53, 54 driving the count wheel 17. The notches 35, 36 in the discs 31, 34 coact with a bar 65 on a lever 66 pivoted at 67. When bar 65 is raised out of the notches its end 68 lifts the slide 41 into the path of pawl 54 so that contacts 43 are closed to give impulses in the secondary clock circuits. Shaft 55 of count wheel 17 carries a cam 59, Fig. 5, which through lug 60 on pawl arm 61 causes pawl 63 to drive the sun wheel 25. Specification 238,843, [Class 139], is referred to.