US2651169A - Clock synchronizing apparatus - Google Patents

Description

Sept. 8, 1953 R. H. BARROWS CLOCK SYNCHRONIZING APPARATUS I Filed Nov. 2:5, 1949 Patented Sept. 8, 1953 CLOCK SYNCHRONIZING APPARATUS Raymond H. Barrows, Johnson City, N. Y., assignor to International Business Machines Gorporation, New York, N. Y., a corporation of New York Application November 23, 1949, SerialNo. 129,017

(01. SSE-.34)

1 Claim.

This invention relates to apparatus for synchronizing clocks, and in particular, to apparatus wherein a master clock having an auxiliary spring type motor and conventional escapement mechanism is controlled from a remote point by anelectrical impulse to come into synchronization with another master clock from which impulses originate.

Ordinarily clock systems comprised of master clocks and so-called secondary clocks, which are controlled by the master clock, are dependent for originating corrections of time upon a settin of the master clock whereupon by devious means all of the secondary clocks are caused to fall into synchronization, such synchronizing being carried out at predetermined periods of time. One such system is explained and illustrated in U. Patent 1,878,931 to Larrabee. In some time systems the master clock may be spring driven, in others an electric synchronous motor may provide the drive, and in still others a combination of the two is used for initiating the driving of the master clock. An example of the lastdnentioned type of master clock driving mechanism is shown in U. S. Patent 2,424,119 to Best. A further application of a master clock in a time system such as has been previously referred to is shown in'a co-pending application, Serial No. 990 filed January '7, 1948, by Johnson and Geiger.

As explained in the co-pending application referred to above, it is obvious that in the case of an electrical power failure the synchronous motor, which normally provides power for driving the master clock mechanism, is brought to rest whereupon a cooperating spring motor takes over the drive and operates until the synchronous motor is again restored to its intended func-- tion. In some time systems two or more'master clocks, sometimes referred to as slave master clocks, are controlled'by a single master clock of exceedingly high accuracy. In these systems the so-called slave master clocks each control a plurality of secondary clocks and may themselves be corrected periodically from a single supervisory master clock controllin all of the satellite time systems. It is to such time-controlling devices that the present invention is particularly adapted.

The principal object of this invention is to provide a simple and efiective means for correcting clocks having spring driven motors by means of periodic electrical impulses.

Other objects of the invention will be pointed out in the following description and claims and 2 illustrated in the accompanying drawings, which disclose, by way of examples, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In Fig. l of the drawings a partial view of a clock mechanism is shown adapted to embody the present invention. The section of the clock shown in the drawing of Fig. 1 represents substantially the clock mechanism referred to in the co-pending application discussed above, as indicated by the corresponding reference characters. It is to be understood, however, that the present invention maybe embodied in any spring driven clock having an escapement similar to that shown in the-drawings.

Fig. 2 of the drawings is a detail view illustrating the precise manner of operation of the invention.

Now referring to Fig. 1 of the drawings a mounting plate 19 is arranged to be fastened in an appropriate manner to a face plate 20 (see Figures 1 and 2, application Serial No. 99-0, J anuary 7, 1948), so as to provide a support for a yoke I3 of an electromagnet l2. The electromagnet I2 is positioned above a balance wheel 18 in suchamanner that an iron slug H mount ed in the periphery of the balance wheel 18 is positioned radially at approximately degrees from the pole tip l2 of the magnet when the balance wheel .18 is at rest. Normally when the spring motor is driving the mechanism the balance wheel 18 oscillates upon a shaft l0 regulatedbya spring 82 under the control of a regulatingarm I82 having a bifurcated end I84 which traddles a regulating pin (not shown). It is to be understood that any conventional escapement mechanism may be employed for driving the balance Wheel '58; however, for purposes of clarificationthe marine escapement mechanism shown in the copending application of reference may be considered most suitable. In this connection a small gear 86 mounted upon a seconds shaft 84, which is journalled between the front plate 20 and a rear plate 22, meshes with a large gear 62, which is driven by the spring motor, in such a way that shaft 84 turns at a rate of 1 R. P. M. Acam I4 is also mounted on the shaft .84 to rotate with the gear v86. A pair of ontact straps H and I8. respectively, are mounted in an insulated plug which is supported between the front andrear plates 20 and 22, respectively. Contacts; are provided on the endsofthestraps l1 and 18 and abearing member l.5.is provided on the strap I8 to cooperate with the cam 14 so that asshaft 84 revolves the 3 contacts l6 will be made and broken for predetermined periods.

In operation the clock mechanism embodying the present invention is given sufficient potential energy by winding its main spring to drive the gear 62 and operate the balance Wheel 18 thereby rotating the shaft 8t at a predetermined rate of one revolution per minute. The regulating arm I82 is then adjusted so that the balance wheel is oscillates at a higher rate than is necessary to cause the clock mechanism to keep correct time; i. e., shaft 8 actually turns at a rate greater than 1 R. P. M., consequently the clock mechanism will gain time at a rate depending upon the advancement of the regulating arm I82. At regular predetermined intervals electrical impulses of predetermined duration are supplied from a suitable electrical source for energizing the electromagnet i2 which through its pole tip 12a (Fig. 2) will attract the slug H thereby stalling the balance wheel i8; consequently, as actual time progresses, the clock mechanism will remain inoperative for the duration of each electrical impulse due to the balance wheel i8 being held stationary, and a corresponding correction in time will be made to compensate for the time normally gained.

One manner in which the above time correcting operation can be carried out is by arranging the member I and the cam M so that contacts it Will be closed for the first 210 degrees of each revolution of the shaft 84 (corresponding in time to approximately the first 35 seconds of each minute) and opened for the remaining 150 degrees of each revolution of the shaft 8 1 (correspending in time to approximately the last seconds of each minute). The clock movement is then regulated by means of the fork 182 to run at a fast rate so that it gains approximately one quarter of a second per minute, and a source for providing electrical impulses is connected to the magnet E2, the contacts It being connected in series therewith. Since contacts l6 are closed from the zero or 60 seconds position to the seconds. position, an electrical impulse during this period will energize the magnet l2, which will therefore stop and retain the balance wheel 18 due to the magnetic attraction of the slug II and the pole tip [2a of magnet l2. During the period of rotation of shaft 84 from the 35 seconds position to the zero or 60 seconds position the contacts it will be open and the magnet [2 can not be energized.

Let it be assumed that an electrical impulse of 2 seconds duration is delivered to the magnet I2 via the series contacts l6 beginning the 58th second of each minute, and that such impulses are supplied regularly by a master clock such as disclosed in U. S. Patent 1,878,931. Also assume that the mechanism shown in Fig. l of the drawings is incorporated into a slave master clock having a spring motor drive, and that the clock is on time. Consequently when the 2 second impulse occurs, the shaft 84 of the slave clock will be at a position corresponding to the 58th second and contacts it will be open so that the magnet i2 is not energized and no time correction is made. If the slave master clock is 1 second fast, for example, the shaft 84 will be at a position corresponding to the 59th second when the 2 second impulse arrives (at the 58th second, actual correct time), and the contacts 16 will be open. However, the contacts [6 will close when shaft 8% revolves to a position corresponding to the 60th second, and since the electrical impulse at thattime (one second later) has a remaining duration of 1 second, the magnet I2 will be energized to attract the slug ii in the balance wheel 18, halting its oscillations for 1 second, the slave master clock will lose 1 second in time thereby being corrected to indicate the correct time. Similarly a full correction of the slave master clock is made when it is 2 seconds fast.

When the slave master clock is more than 2 seconds fast a correction will be made of the order of 2 seconds each minute until correct time is again indicated by the slave master clock. With the arrangement of cam l4 and member l5, described above, corrections up to 37 seconds fast in the slave master clock can be compensated.

It is obvious that no correction can be effected electrically if the slave master clock is slow, except by regulating the arm I82 to cause the spring motor under control of the balance wheel 18 to drive shaft 84 at a higher rate. For most practical purposes, however, a correction of a fraction of a second per minute is sufficient in the slave master clock so that the specific arrangement illustrated, by which the slave device gains a fraction of a second during the first part of each minute and is corrected to lose what has been gained at the end of each minute, is quite adequate.

The principal advantage in apparatus of the type herein described is in its simplicity, its adaption to existing equipment Without major redesign, and its smoothness of operation whereby the balance wheel of a spring clock is adjustedby magnetic force having no tendency to jam or damage the delicate escapement mechanism therewith associated.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claim.

What is claimed is:

In a secondary clock for use in a clock system wherein a spring-driven secondary clock is periodically brought into time agreement with a master clock by an electrical impulse transmitted by the master clock during the final portion of each of predetermined units of time, the combination of a spring-driven marine escapement mechanism in said secondary clock including a balance Wheel constructed and arranged to oscillate about a normal rest position at a frequency greater than that necessary to measure accurate time as defined by the master clock and composed principally of a non-magnetic material, a magnetic slug insert mounted in the periphery of said balance Wheel, a time shaft rotating under control of said escapement mechanism at a rate in excess of one revolution per said unit of time, electrical contacts, a cam on the said shaft constructed to close said electrical contacts during an initial portion of said unit of time as measured by the secondary clock, an electromagnet adjacent the periphery of said balance Wheel and so located as to attract when energized the said slug and arrest the oscillation of said balance Wheel at an angular position of the balance wheel other than said normal rest position, a circuit in which said contacts and said electromagnet are connected for receiving the electrical impulse from the master clock to energize said electromagnet when said cam closes said electrical contacts during said initial portion and when said initial portion concides with the transmission of the electrical impulse from the master clock.

RAYMOND H. BARROWS.

References Cited in the file Of this patent UNITED STATES PATENTS Number Number Name Date Von Orth July 10, 1894 Junghans May 16, 1939 Hansen Dec. 26, 1939 Mullan Apr. 30, 1940 Dicke July 8, 1941 FOREIGN PATENTS Country Date France Apr. 9, 1934 Germany Feb, 23, 1938

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