Patent GB-236199-A (GB)
Title: Improvements in or relating to synchronizing clock systems
IPC: G04C13/03
Filed: 1925-06-15
Abstract: 236,199. International Time Recording Co. of New York, (Assignees of Bryce, J. W.). June 26, 1924, [Convention date]. Electric clocks; synchronizing hands. - In a synchronizing clock system the master clock sends normal regular impulses and fast regular impulses to the secondary clocks, and selective means are provided at the master clock for suppressing the normal impulses, the fast impulses, or both. The master clock, Fig. 1, carries on its minute arbor 10 cams 12, 13 which close contacts 14, Figs. 1 and 3, during the synchronizing period from approximately forty-four to fifty-nine minutes after the hour. A further cam 15 closes contacts 16 for a few seconds once each hour, these contacts then opening just before the contacts 14 open. The master clock also actuates a minute cam 18 for the minute impulse contacts 17 in the usual way, further quick-acting contacts 19 being operated by the escapement 11. A ratchet 22 on the minute arbor 20 of each secondary clock, Fig. 2, is advanced by a part each time the magnet 21 receives an impulse from the master clock and a synchronizing cam 23 on the same arbor coacts with contacts 25, 26 so that contacts 25 are closed from approximately twenty-nine minutes till fifty-nine minutes after the hour and contacts 26 are closed from fifty-nine minutes after the hour till twenty-nine minutes after the following hour. Current is supplied to lines 30, 31, Fig. 3, of which 31 is shown earthed at C for simplicity to fcrm a return with the secondary clocks. Assuming that the secondary clocks are not yet in the synchronizing period the normal regular impulses from contacts 17 are given through circuit 30, 32, 33, 34, 17, 35, 36, 37, and 31. Master relay coil 36 thereby attracts its armature 38 once per minute, causing current to flow from wires 30 and A through wires 39 and contacts 25 to the impulse magnets 21 of the secondary clocks. Minute impulses are also transmitted from wire 30 through 40, 41, 45 to wire B. At the beginning of the synchronizing period contacts 14 close completing a circuit 30, 32, 33, 42, 14, 43, 44, 31; relay 44 breaking the B circuit, at 45, so that during the synchronizing period normal minute impulses are transmitted over wire A only. Three secondary clocks X, Y, and Z are shown at correct time, fifteen minutes fast, and fifteen minutes slow respectively. For clocks X and Z the contacts 25 are closed and these clocks receive minute impulses in the usual manner. At clock Y, however, contacts 25 are open so that this clock remains stationary until the end of the synchronizing period. Just before the end of this period contacts 16 close completely a circuit 30, 32, 46, 16, 47, 19, 35, 36, 37, and 31; contacts 19 are closed in rapid succession, rapidly anergizing and de-energizing relay 36. Meanwhile contacts 25 at clocks X and Y are open but at Z are still closed, whereby clock Z receives rapid impulses until it agrees with the master clock, when its contact 25 open. Contacts 16 and 14 open, contact 45 is remade and normal conditions are resumed. To step up or slow down the entire system an amount exceeding that of the synchronizing period, for instance for a daylight saving correction a manual switch 49 is moved to neutral or to contact with line 48<1>. If the switch is at neutral all the secondary clocks are halted until they are nearly in agreement with the master clock, the switch being then returned and the clocks being synchronized at the next hour. If the switch is connected to wire 48<1> the fast impulses contact 19 is brought into circuit, stepping up the clocks rapidly.