Patent GB-151302-A (GB)
Title: Improvements in and relating to electrically operated synchronizing clock systems
IPC: G04C11/04
Filed: 1919-03-20
Abstract: 151,302. White, A. E., (International Time Recording Co.). March 20, 1919. Electric clocks.-An independent (spring- driven) clock which may be such as is ordinarily employed for driving time-recording mechanisms is combined electrically with a standard or master clock so that its mainspring is wound thereby and its gain or loss is corrected. The distant clock may however be merely an indicator receiving impulses from the standard. The master clock, Fig. 1, has its anchor arbor 5 and its escape wheel arbor 8 furnished respectively with a finger 6 and an arm 9 to close momentarily, once a minute, a circuit 22, 23 wherein in the case of an impulsedriven distant clock an electro-magnetic key (not shown) in another circuit is provided to transmit the impulses to a ratchet-driven indicator. Synchronising; winding-apparatus; electric.-In the controlling-clock the circuit of a local battery is made and broken in one loop at each of two instants separated by an interval of about fifteen minutes and again in a parallel loop at each of two other separated instants. A wave-cam operated by an electro-magnetic ratchet in each loop closes a line circuit, and at the end of the interval opens it again. In each controlled clock it is arranged that the line-current passing in the first interval shall check a gain or allow recovery of a loss, and that the current passing in the second interval shall wind-up the mainspring. The current in the line circuit may be derived from an ordinary power or lighting plant. The master clock is enabled as above described to close once a minute a circuit 22, 23, Fig. 1, which may be otherwise complete, and this circuit is divided through two electro-magnets 24, 33 for driving ratchet wheels 25, 34, the driving-action being restricted to certain special instants in the hour by two pairs of normally parted contacts 16, 17 which are bridged only at these instants by conductive bits 18, 19, 20, 21 in the peripheries of hourly-rotating non- conducting-disks 14, 15. For the ratchet wheel 25 these instants are fifteen minutes before the hour and the even hour itself, while for the ratchet wheel 34 they are seventeen and twentyseven minutes after the hour. Cam wheels 26 and 35 attached to the ratchet-wheel 25, 34 act on pairs of normally-parted contacts 27, 36 ;n parallel portions 29, and 39, 38, 37 of the circuit 30, 28, 41, 31 to the controlled clock; accordingly, these portions are prepared for the passage of current during the last quarter of the hour and the selected ten minutes. The controlled clock, Fig. 2, driven by its own going barrel 43, contains planet-gearing between wheels 65, 72 which gear respectively with a fly 75 and the escape-wheel 68. The line-circuit 30, 31, divided into routes 93, 95 and 96 through electro-magnets contains pairs of normally parted contacts 90, 94, and 98 associated with cams 87, 88, and 89 on the centre or minutehand arbor 86. If the clock be fast, the cam 87 lets current pass before the termination of the fifteen minutes closure due to the disk 14 and cam 26 in the master clock, and the electro-magnet 83 accordingly applies a detent 84 to the balance 70 till the interval ends. The cam 88 acts on the contacts 94 during the third quarter of the hour, and should leave them parted again just when the fifteen minutes' closure aforementioned begins; but if the controlled clock be slow, current passes at the commencement of the closure and the electro-magnet 80 disengages a detent 82 from the fly 75, so letting the clock race till the minutehand reads a quarter to the hour and the camaction ceases. The electro-magnet 76 operates the winding-ratchet 49. when the disk 15 and cams 35, 89 allow current to pass; this occurs for ten minutes or less, and the current is broken into impulses by a star wheel 11 and a finger 7 respectively on the appropriate arbors of the master clock. If the distant clock is merely an indicator, the impulses obtained from the star wheel 11, not being required for winding, are utilized to operate the driving-ratchet of the indicator more rapidly, if required, to correct slowness, and the current for correcting gain obtained as previously described, is made to break the impulse circuit by means of an electro-magnet in the indicator if the latter be too fast, until the master clock breaks the circuit of this magnet on synchronism being reached. Instead of stopping and advancing an independent distant clock as in Fig. 2, the master clock may' regulate its pendulum or balance. In this case, an interrupter such as 11 is provided in the distant clock to affect both tracks 93, 95 so that one of the electro-magnets 83 or 80 may shift the regulator one way or the other. In another arrangement for synchronising, shown in Fig. 11, the master clock sends to line for predetermined periods a gradually-varying current by means of a rheostat 118 and a contact arm 117, mounted, for example, on the hour arbor, and in each controlled clock a similar arrangement 120, 119 provides a similarly-varying current in a local circuit for a corresponding period. These two varying currents are used to control a differential polarized relay 122, 123 in the controlled clock in such a manner that if the currents are in phase, which will be the case when the clocks are in synchronism, nothing happens, but if during the periods of flow one of the currents be out of phase with the other, the relay will be caused to direct a current through one or the other of the electro-magnets 131, 133 and operate the retarding or accelerating means in the controlled clock as before described, and thus establish synchronism.