Patent GB-365677-A (GB)
Title: Improvements in electric time systems
IPC: G04C13/03
Filed: 1930-11-01
Abstract: 365,677. Electric clocks. INTERNATIONAL TIME RECORDING CO. OF NEW YORK, Endicott, New York, U.S.A.-(Assignees of Harrison, L. S. ; 33, Center Street, South Orange, New Jersey, U.S.A.) Nov. 1, 1930, No. 32923. Convention date, Nov. 14, 1929. [Class 139.] In a clock system of the impulse type wherein each secondary is individually adjusted onwards or backwards at the synchronizing time according to its chronological condition, the synchronizing control has associated with it a pre-settable group controlling arrangement whereby the clocks as a whole may be accelerated and/or retarded by predetermined pre-set time amounts. The master clock consists of a chronometer which closes a single light contact once a minute, these impulses passing to a " master control unit " which in turn controls the various switches of the self-synchronizing system. In addition two manually pre-set mechanisms are provided for setting the entire system ahead and back. Clock cases.-A watertight case of non- corrosive material consists of a back-plate 20 (bolted to a wall by bolts 21) having a groove containing waterproof packing 22. The cover 25 is hinged at 24 to the back-plate, its edges engaging the packing 22 when a clamp 26 is fastened. This casing houses the master clock (dial 61), the " set ahead (30, 171, 154) and " set back " (29, 171, 154<1>) pre-set mechanisms, and the " master control unit (dial 28). In each case the glass covering the dial is held against a packing ring by clips. In the case of the master clock and " master control unit " dials the screws which hold these clips also grip an annular ring the inner end of which presses against the dial. To the lower end of the case 25 is attached a watertight box, for fuses 42 and cable lead-in 40, having an independent cover 43. Synchronizing.-The master movement 50 has a lever escapement and a magnet 51 which receives an impulse once a minute and winds the mainspring through armature 52, arm 53, and ratchet and pawl 56, 55. For a detailed description of this mechanism, Specification 236,199, [Class 139, Watches &c.], is referred to. A seconds hand 60 reads against a dial 61 and once each minute a contact 58 is closed by cam 59 to transmit the impulses. The invention involves a self-synchronizing system, such as described in Specification 236,199 having three transmission lines one of which is used for the rapid stepping-on impulses at the synchronizing time. The switches for selecting this line are actuated by the " master control unit," Fig. 12, the magnets 69 of which receive an impulse once a minute from the contacts 58, Fig. 2, of the master clock. Armature 70, through arm 74, pawl 80, and ratchet 81, drives a shaft 87 carrying minute hand 88 and geared to hour hand 89. Minute shaft 87 carries cams 92, 93 controlling contacts 94, 95 respectively, Figs. 12 and 15. Contacts 94 close at the break of the 58th minute impulse and open at the break of the 59th impulse. Closed contacts 94 cause the 59th impulse to initiate the rapid stepping-on impulses (described below), the mechanism for which consists of an electric motor 101, Fig. 2 ; this motor is normally arrested by a brake device which is disabled to free the motor when a magnet 119, Fig. 15, is energized. When running the motor drives cams 110, 113, thirty and three revolutions per minute respectively, cam 110 closing contacts 132 once a revolution and cam 113 closing contacts 130, 131 once each revolution. The " set ahead " and " set back " controls for pre-setting the advance or retard of the system are shown on the right and left of Fig. 7, the shaft 141 in each case being driven by electromagnetic ratchet and pawl mechanism identical with that described for the " master control unit," Fig. 12. Shaft 141 rotates once for 60 impulses and is geared to wheel 142 and a wheel 143 rotatable on a shaft 144, Fig. 10, to which is keyed a gear 147 normally engaging a locking member 148. Normally gear 143 meshes with wheel 142 and with a wheel 156 carrying a cam 159, but when shaft 144 is slid axially the parts are as in Fig. 10 and the handle 154 may be turned to adjust cam 159, the amount of adjustment being shown by a pointer 171 and scale 29 or 30, Fig. 1. Cam 159 has an indentation 160a, of which one side is radial and the other at an angle thereto, coacting with cam-wiper 160 on an arm 161 which carries one of a normally open pair of contacts 170, or 169. A lever 162 pivoted at 163 to cam 159 has one end in a limiting notch 165 and the other, bifurcated, end 166 embraces a button 167. When cam 159 is moved counterclockwise, wiper 160 is cammed out and contacts 170 closed. When cam 159 moves clockwise with lever 162, the wiper finally snaps down behind the point 162a of arm 162 and re-enters notch 160a to open contacts 170 abruptly. To set the system, say, 15 minutes ahead the shaft 144, Fig. 10, is moved axially pointer 171 (and therefore cam 159) is swung counterclockwise until it reads 15 minutes on scale 30 and the shaft restored, Thereafter, at the synchronizing period the system is advanced 15 minutes, as described below, and cam 159 concurrently returns clockwise by its ratchet and pawl drive, to reach its initial position at the end of 15 minutes. A manually-actuated key 182 is provided for advancing the system any desired amount. Fig. 15 shows the control circuits at the master clock and " master control unit," and two secondarv clocks 200. Specification [236,199, [Class 139, Watches &c.], is referred to for the construction of the secondaries and the self-synchronizing action thereof. Relays 205 and 208 are energized when contacts 170 (advance cam 159) are closed. Relay 214 is energized when contacts 169 (retard cam 159) are closed. Relay 205 closes contacts 206, 207 (normally open) ; relay 208 opens contacts 213 (normally closed) and closes contacts 209 .. 212 (all normally open) ; relay 214 opens contacts 216 (normally closed) and closes 215 (normally open). Coil 217 is energized once a minute from master clock contacts 58, closing contacts 223 to energize magnet 51 for winding the master clock mainspring and to energize magnet 69 (of the " master control unit " ratchet device) and magnet 224 (closing contacts 232). Magnet 69 rotates cams 93, 92 to close contacts 95 (at the break of the 60th minute impulse) and 94 (at the break of the 58th). At the secondaries, contacts 202 open at the hour and close at 15 minutes past the hour, and contacts 203 vice versa. With contacts 232, 95 closed, minute impulses over both A and B wires are transmitted to the secondaries. At normal synchronizing the slow clocks are stepped-on until they show the hour, contacts 202 open and contacts 203 close and connect the clocks to the B line, which is dead until contacts 95 are closed at the master hour to restart all clocks on time. When the 59th minute impulse occurs a circuit over contacts 223, 94 energizes motor 101 and brake release magnet 119. The impulse lasts for about two seconds during which contacts 94 close and the motor rotates cam 113 to close contacts 103, 131. The control of the motor is thus transferred from contact 94 to contact 131. Magnet 119 closes contacts 121, bringing into circuit contacts 132 which are closed 30 times a minute by cam 110 and send rapid impulses over wire 235 to line A, stepping-on the slow secondaries through contacts 202. This continues until cam 113 (3 revolutions per minute) has made one rotation and opens contacts 103 to break the motor circuit (94 being already open). At the next minute impulse, contacts 95 close to advance all secondaries on time, contacts 203 being closed to connect the clocks to the B line. Setting ahead. If the right-hand device, Fig. 7, has been set as above-described to advance the entire system, say 15 minutes, contacts 175 are open and 170 closed to energize relays 205, 208. When the shaft 144, Figs. 7 and 10, is restored inwardly after setting, contacts 175 are reclosed and energize armature 101 and magnet 119 through contacts 209. Contact 210 energizes magnet 247, closing contacts 248, 249 and opening 242. The two-second impulses over contact 132 now pass over contacts 248, 207 to the A and B lines and through the secondaries according as contacts 202 or 203 are closed. These two-second impulses also pass over 121, 250, 261, 212, 226, 227 to energize magnet 69 and advance the " master control unit " also. The " set-ahead " drive magnet 137 is also energized and restores the right-band device, Fig. 7, clockwise to initial position after 15 impulses, whereupon the above circuits are broken and the system resumes normal operation. Setting back. For this, the left-hand device of Fig. 7 stops the entire system for the desired period with the exception of the master clock. The cam 159 when set, closes contacts 169 to energize relay 214. This opens contacts 216 stopping all the secondaries and the " master control unit." Contacts 215 are closed to energize magnet 137<1> for stepping the " setback " device (left, Fig. 7) clockwise until at zero position contacts 169 open and the system resumes normal operation.