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Publication numberUS1310786 A
Publication typeGrant
Publication dateJul 22, 1919
Filing dateNov 16, 1918
Priority dateNov 16, 1918
Publication numberUS 1310786 A, US 1310786A, US-A-1310786, US1310786 A, US1310786A
InventorsJames W Bryce
Original AssigneeInt Time Recording Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Synchronizing clock system.
US 1310786 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Patented July 22, 1919.




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Patented July 22, 1919.






Specification of Letters Patent.

Patented July 22, 1919.

Application filed November 16, 1918. Serial No. 262,755.

To all whom it may concern:

Be it known that I, JAMES W. Baron, a citizen of the United States, residing at Binghamton, in the county of Broome and State of New York, have invented certain new and useful Improvements in Synchronizing Clock Systems, of which the following is a full, clear, and exact description.

In an application for Letters Patent filed by me on May 21, 1918, Serial No. 235,813, I have shown and described a synchronizing clock system in which a master clock controls and maintains at all times in substantially perfect synchronism with itself a plurality of secondary clocks all connected with the circuit from the master clock. The underlying principle of operation of this system is that the master clock at predetermined intervals connects to the line a source of current for definite periods of substantial duration. Each secondary clock is equipped with means for retarding and means for accelerating its rate, and with two circuit controllers which at definite instants of time, as this is indicated by the hands of the secondary, close a path from the line through one or the other of the means which control the rate of the clock and maintains such parts closed for definite and predetermined intervals of substantial duration.

From this it follows that when either of these periods overlaps that during which current is sent from the master clock, as they will do only if the secondary clock be too fast or too slow, then the current sent or controlled by the master clock will actuate the rate controlling means, retarding the rate of the secondary, if it be too fast, or accelerating it if it be too slow, until the secondary is brought into exact synchronism with the master clock and no part of the said periods of closure in the two clocks occur simultaneously.

The present application is based u on an improvement on this system or met 0d of synchronizing, and involves the same general principle of operation, but effects it by substantially diflerent means. That is to say, the fundamental scheme is to provide a master clock which by means of a controlling medium such as electricity or any other suitable fluid may regulate or control any number of secondary clocks designed and constructed to be capable of keeping differential time, or in other words which may be stopped or slowed down, run at proper or normal rate, or be accelerated or speeded up as may be necessary for conditions of synchronism with the master clock assumed to keep true time. 7 According to my present invention, to state it in somewhat general terms, I proceed as follows: I equip the master clock with any suitable means that will send for any redetermined interval to line a current whic varies in strength or voltage in a definite and predetermined manner. I also provide each secondary clock with the same or a similar means for sending from a local source a current for the same interval which varies in strength or voltage in the same way, and with each of such secondary clocks, I employ a device such as a polarized relay which is energized by both of these currents. If the secondary is exactly on time the interval during which it sends this varying current coincides exactly with that during which the master clock sends its varying current to line, and the relay or whatever mechanism may be employed for the purpose, being oppositely magnetized by the two currents is so arranged that it responds to neither, but remains still. If, however, the secondary clock is not on time, for example if it be too fast, then its varying current will be out of phase or step with that on the line, and as a consequence the relay will be unbalanced and being polarized, will respond to that current which is the stronger, and throw in a device which stops or retards the secondary clock until the current which it sends exactly corres ends to that from the master clock. On t e other hand, should the secondary be too slow, then the line current will predominate and cause the relay to throw in an accelerating device which speeds up the secondary until the current conditions are again exactly balanced. In other words, in this system it is not the mere overlapping of periods of closure of circuits in the secondary and over the line that accomplishes the synchronism, but the departure from corresponding varying strength or voltage of two currents during overlapping periods that is effective for the same purpose.

This invention I have illustrated in the' accompanying drawings which are merely intended to illustrate the system in a practical and typical form without reference to the specific nature of the mechanism employed.

Figure 1 is a diagram of the system in its most approved and practical form.

Fig. 2 is a similar but greatly simplified illustrated diagram of the same improvement, and

Fig. 3 is a detailed sectional View of a differential gear used in connection with a secondary clock.

I have shown but one secondary clock, but it will be understood that any greater number may be employed in connection with the same controlling circuit. I may therefore refer to the simplified diagram of Fig. 2 for the purpose of describing this invention.

In this figure A represents a master clock of any approved construction and B one of the secondary clocks that are to be controlled thereby.

In the master clock as the means for sending a varying current to line I have shown a contact arm 1 which is mounted on one of the driven shafts of the clock, as, for example, the hour arbor, and which sweeps over the plates of a resistance coil or rheostat 2 in the circuit of any proper source'of current 3, and line. By this means the master clock sends to line for any desired interval a current which may be assumed to start its fiow at maximum and to gradually weaken to any desired point by the inclusion in the circuit of a gradually increasing resistance. The line is designated by the numerals 4=4.

In each secondary clock the same or any similar means is used, that is to say a contact arm 5 on the hour arbor, a resistance coil or rheostat 6 and a source of current 7 which are included in a local circuit 8, 8. The source of current may be the same as that which sends to line, or it may be any other, either of the same voltage or any other, provided that the variatlon in the current stren h or voltage be in the same direction an in exact proportion, as the neutralizing effects in such case may be secured by windings and other well known means.

In each secondary clock is a dillerential polarized relay comprising two coils 10 and 11 and an armature 12 pivoted to the permanent magnet 13 forming part of the magnetic circuit of the instrument. The connections of the coils, the former of which is in the line 4, 4, and the latter in the local circuit 8, 8, are such that the two currents neutralize each others eflects or are opposed. If therefore the two currents are equal or alike in their magnetizing efi'ects, the armature 12 is not moved, but if: the current in coil 10 be the stronger, then, say a north pole will be produced in the free end of the core, and the armature will be repelled. If,

however, the current in coil 1J1 preponderates, then the armature under the influence of a south. pole will be attracted.

Normally the local. circuit. 8, 8 is interrupted, but when a current flows over the line an electric-magnet 14 therein closes this circuit by its attraction upon an armature 15.

The driving train of the secondary clock contains a differential gear shown in Fig. 3, which device may be mounted on the minute arbor 16. This arbor carries a pinion 17 which is in mesh with the clock train, and on the same shaft is also mounted a bar or arm 18, on the opposite end or ends of which are carried the floating difi'erential gears 19 which mesh with gears 20 and 21 at right angles thereto, the former oi which is fast on a hub 22, loose ontheshatt 16 and carrying a gear 23 fixed tbsaid hub which is designed to mesh with the gear on the shaft of the escape wheel 24.

The other gear wheel 21 is mounted on a hub 25, loose on the shaft 16, and'carrying'a gear wheel 26, which meshes with a pinion 27 on a spindle carrying a fan 28.

Under the assumption that the secondary clock is exactly on time, the polarized relay will not be actuated; because the magnetizing eifects oi the currents in coils 1 0 and 1:1 will just balance, notwithstanding" that both currents are continuously varying in strength or voltage: But lee it be assumed that the secondary is ahead of time, then it sends its current through relay coil 11 ahead of the line current in coil 1 0,- or in general its strength will be greater than the line current. Under these circumstances the armature will be attracted toward the pole of the relay and onto a stop 29 which sends current through relay 30 that attracts an avmat ure 31 carrying a friction brake 32'that stops the balance wheel 38 and therefbre the clock, until the line current has reached the strength that neutralizes the action of the relay, whereupon the clock is started in syn chronism with the master clock.

Shouldmhe secondary clock be slow, the opposite eflect is produced. That is to say, the line current will preponderate, the armature 12 will be repelled against step 34- and current will be sent through relity 35 which operates to release the normally locked fan 28, thus permitting the clock to speed up until its current neutralizes that of the line, whereupon the fan is again locked and the clock continues to run under the corn trol of its escapement 33 In the practical use of this system it is desirable that some means be employed in the nature of a current. adjusting device on the synchronizing or line circuit to compensate for variations in line resistance caused by temperature changes, the addition or removal of secondary clocks and the like, and such a device is shown in Fig. 1.

In this figure a difierential polarized relay is used in connection with the master clock, one coil 36 of which is in the circuit of the source 3 while the other, 44, is in a branch to line through a brush 37 adapted to slide over the contacts of a resistance coil or rheosat 38.

The brush 37 is carried by the core 39 of the solenoids 40 and 41, the former connected to the other line wire through a stop 42 and the latter through a stop 43.

With this arrangement, if the resistance 1 is partially thrown in by the movement of the arm 1, it will reduce the current through coil 36 and the armature 45 will be attracted. This will cause it to close the circuit of solenoid 40 whereby the core 39 is moved to the left, throwing in resistance 38 until the current in coil 44 balances the effect of that in coil 36, when armature 45 will be released and move to its neutral position between the two contacts 42 and 43. This will, therefore, establish a current in the line and relay coil 10 of the secondary which is either equal to or some multiple of that established in the master clock circuit. It is the function of the solenoids 40 and 41 to maintain this condition and they thus change the current in the line in accordance with true time and also compensate for any changes in the line resistance.

It is manifest that the current, so far as synchronism is concerned, may be varied throughout the entire 24 hours or through any lesser period without departure from the invention. It is also obvious that instead of using a continuous current and varying its strength or voltage in the manner shown or in any other known way, I may use an alternating current and var its effoot by any variation of the power actor of the circuit in a manner now known to electricians. In case a varied alternating current be used, of course suitably responsive devices must be used in the system instead of the specific relays here shown.

Having now described my invention, what I claim is:

1. In a synchronizing clock system, the combination with a master clock, a circuit, one or more secondary clocks connected with said circuit and adapted to be maintained in synchronism with the master clock, and local circuits in said secondary clocks, of means in the master clock for sending to line for any predetermined intervals a current varying in a definite manner, means in the secondary clock or clocks for sending over the local circuit a corresponding current for the same interval, means actuated by the said two currents and normally neutralized thereby when the said two currents are in phase, and means controlled by the preponderating eflect of either of said currents when out of phase to retard or to accelerate the secondary clock or clocks.

2. In a synchronizing clock system, the combination with a master clock, one or more secondar clocks, a line circuit to the secondary 0100 {S and a local circuit in each secondary clock, of means in the master clock for sending to line a periodically varying current, means in each secondary clock for retarding or accelerating its rate, and means actuated oppositely by the said two currents and neutralized thereby when they are in phase, but rendered active by the preponderating strength of either to thereby actuate the retarding or the accelerating means whereby the efiects of the two currents will be equalized and the clocks brought into synchronism from any departure therefrom.

3. In a synchronizing system, the combination with a master clock and one or more secondary clocks, a line to the secondary clocks and a local circuit in each secondary clock, of means in the master clock for sending to line for any given interval a definitely varying current, means in each secondary clock for sendin over its local circuit for the same interva a corresponding current, means in each secondary clock for retardin or for accelerating its rate, a polarized difierential relay oppositely actuated by the said two currents, whereby when either of the said currents exerts a pre ponderating effect the relay will be actuated to throw in the retarding or the accelerating means and thereby reestablish the neutralizlng effects of the two currents and synchronize the secondary clock.

4. A synchronizing clock system havin in combination a master clock, a source 0 current, a line, a secondary clock, a source of local current, a local circuit therein, means driven by the master clock for varying the resistance between the source and the line, means in the secondary clock for similarly varying a resistance between the local source and the local circuit, the said two means being disposed to operate during the same intervals, a differential device energized by the said two currents, means for retardin and means for accelerating the rate of t e secondary clock controlled by the differential device and one or the other thrown into operation by the preponderating magnetizing efl'ect of either current to reestablish their neutralizing effect and synchronize the secondary with the master clock.

In testimony whereof I hereunto afiix my signature.


Come: 0! this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4368987 *Jun 25, 1980Jan 18, 1983The United States Of America As Represented By The Secretary Of The NavyConjugate-phase, remote-clock synchronizer
U.S. Classification368/56, 368/184, 968/508
International ClassificationG04C11/00
Cooperative ClassificationG04C11/005
European ClassificationG04C11/00C