Patent GB-370205-A (GB)
Title: Improvements in or relating to syncronized clock systems and secondary clocks therefor
IPC: G04C13/03
Filed: 1931-04-23
Abstract: 370,205. Electric clocks. INTERNATIONAL TIME RECORDING CO. OF NEW YORK, Endicott, New York, U.S.A.-(Assignees of Allen, R. C. ; 2005, Tracy Street, Endicott, New York, U.S.A.) April 23, 1931, No. 12059. Convention date, April 26, 1930. [Class 139.] Synchronizing.-In a clock system each secondary has an impulse magnet and an impulse accepting and rejecting device which permits or suppresses effective energization of the magnet according to the direction of flow of the impulses and according to the chronological condition of the secondary clock. At the master clock, Fig. 1, fed from A.C. mains 100 through a transformer 102, contacts 17 close once a minute, contacts 19 close once every two seconds, contacts 14 open from 44 minutes to 59 minutes 50 seconds after the hour, and contacts 16 close from 59 minutes 10 seconds to 59 minutes 40 seconds. At each secondary clock, Fig. 1a, a cam 23 (connected to the motionwork) opens contacts 25 and closes contacts 26 at the 59th minute and reverses this condition after the hour and before the 44th minute. At the master clock a rectifier 112, preferably of the dry-plate copper oxide type, transmits impulses of +ve polarity over line 118 to switch 120 and of -ve polarity over line 116. From the hour to 44 minutes past, contacts 17 close each minute to energize magnet 36 and close contacts 38 so that an impulse of +ve polarity is sent over line 118 and switch 120 to the line A for the secondaries, the system being a single wire one. At 44 minutes contacts 14 open, magnet 44 is de-energized and switch 120 drops to reverse its connections so that -ve impulses from line 116 are now sent to the secondaries. This continues until 59 minutes 10 seconds, when contacts 16 close for 30 seconds during which time contacts 19 energize magnet 36 once every two seconds to close contacts 38 and transmit rapid -ve impulses to line A. Just before the hour, contacts 14 are reclosed, magnet 44 is energized and switch 120 resorted to the position shown, and at the hour, contacts 17 cause the first +ve impulse to flow over line A. Each secondary has a copper-oxide rectifier 122-which may, however, be a one-way device such as a valve or asymmetrical conductor -which permits the substantial passage only of impulses of +ve polarity, as indicated by the arrow. For a secondary X showing correct time, +ve impulses from the hour till 44 minutes, and -ve impulses from 44 minutes until 59 minutes are received by the secondary over contacts 25 so that magnet 21 operates the ratchet drive for the clock hands. At the 59th minute of the secondary, contacts 25 open and 26 close. The rapid stepping-up -ve impulses cannot, however, pass through rectifier 122 and contacts 26 to affect magnet 21 but at the hour the first positive impulse restarts the clock on time. For a fast clock Y contacts 25 open as soon as the clock hand is at the 59th minute and stays thus until the first +ve impulse passes its rectifier. For a slow clock Z the rapid -ve impulses from contact 19 (from 59 minutes 10 secs. to 59 minutes 40 secs.) and over contacts 25 step the clock on until its hand is at 59th minute, whereupon its contacts 25 open. In a modified secondary clock contacts 26 are omitted and the rectifier is in parallel with contacts 25. At the right hand half of Fig. la is shown the arrangement for a remote three-wire clock system. At the remote point is an A.C. source 100A, transformer 102A and rectifier 112 A which send +ve and -ve impulses over the lines A<1>, B<1>, C<1>. Magnet 128 is energized to close 132 (to send +ve impulses over 136) when +ve or -ve impulses are on line A; but only -ve impulses from line A can flow through rectifier 124 to energize magnet 130 so that 134 closes to pass -ve impulses from 112A over line B<1>.