PATENT SPECIFICATION ‘DRAWINGS ATTACHED

No. 9078/57.

Index at acceptancez—Class 139, ASX.

International Classificationze—GMc.

COMPLETE SPECIFICATION

Improvements in or relating to a ‘Watch or Clock

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We, BULOVA WATCH COMPANY, INc., of75—20 Astoria Boulevard, Flushing 70, NewYork, United States of America, a Corpora-tion organised under the laws of the State ofNew York, United States of America, do. here-by declare the invention, for which we praythat a patent may be granted to us, and themethod by which it is to be performed, to beparticularly described in and by the followingstatement:—The present invention relates to a watch 01'

clock the timepiece mechanism of which isdriven by a vibrator, preferably of the tuning—fork type. The vibrator and the timepiece are[so interconnected with each other that the rateat Which the timepiece mechanism is drivenis proportional to the natural frequency ofoscillation of the vibrator.When the timepiece is first manufactured,

the vibrator is so constructed that its naturalfrequency is such as to cause the timepiecemechanism to be driven with an accuracy ofapproximately plus or minus three minutes perday, -i.e. while the vibrator Will drive the time—piece mechanism at a constant rate which isexactly proportional t0 the natural frequencyof the vibrator, this natural frequency willprobably -be such that the timepiece mechanismis driven either slightly too fast or slightly tooslowly, so that the timepiece Will gain or lose,‘a certain constant amount each day.

According to the present invention there isprovided a watch or clock having a timepiecemechanism and a tuning-fork type vibrator fordriving the timepiece mechanism, wherein thevibrator and the timepiece mechanism are sointerconnected with each other that the rate atwhich the timepiece mechanism is driven isproportional to the natural frequency of oscil-lation of the vibrator, means being providedfor varying the natural frequency 10f thevibrator,,lsaid means being associated with atleast one the of .said vibrator and comprisinga deformable element attached to said tine,

[Pn'ca 3:. 611.]

828-357Date of Application and filing Complete Specification: March 20, I 957.

Application made in United States of America on Oct. II, I956.

Complete Specification Published: Feb. I 7. I 960.

said element being capable of deformation intoany of a plurality of differing configurationsso» as to vary the disposition :of the centre ofgravity of said element with respect to the axisof oscillation of said tine.

Exempiatory embodiments of the presentinvention are diagrammatically illustrated inthe accompanying drawing, in which:

Fig. 1 is a schematic representation of avibrator for driving a timepiece mechanism,the natural frequency of oscillation of whichvibrator is adjustable; and

Fig. 2. is a fragmentary view of a furtherembodiment of a vibrator the natural fre-quency of which can .be varied.

Referring now to the drawing, and to Fig.1 thereof in particular, there is shown a tun—ing—fork type vibrator 1 having a base portion2 and a pair of tines 3 :and 4, the vibratorbeing soldered, welded or otherwise fixedlysecured to a member 5 which, in turn, is suit-ably fixed to the base plate of the timepiece,as, for example, by 'a pair of screws 5a, insuch a manner that the titles are freely oscillat-able about their‘respective axes -of oscillation31 and 41. 'A pawl 6 which has a natural frequency con-

siderably greater than, and preferably at leasttwice as great as, the maximum obtainablefrequency of the vibrator is attached to thetine 4, the other end of the pawl, which mayhe in the form of a leaf spring, being in en—gagement with a ratchet wheel 7. The ratchetwheel 7 is preferably so positioned that its axisof rotation is normal to the plane of oscillation-of the vibrator.Each of the tines carries at or near its free

end an electrical oscillating component in theform of a magnetic drum 8 which is com-posed of a cup-shaped member 8a and a batmagnet 8b made of a very stmng magneticmaterial such as Alrnico; Each of the drums isthus formed with an inner annular chamber8c.

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A pair of tubular carriers 9 project into thetwo chambers 8c, respectively, each of thesecarriers being at one of its ends either directlyor'indirectly secured to the base plate. One ofthe carriers carries a coil 10 and the othercarries a coil 11 which has approximately fiveto six times as many turns as the coil 10, thearrangement of the parts being such that eachcarrier 9 encompasses the respective bar 8bwith clearance and that each cup—shapedmember 8a encompasses the respective coilwith Clearance, so that the magnetic drums arefreely movable relative to the stationary car—riers and coils. Oscillation of the tines 3 and4 is therefore not impeded, and each of thecoils together with its magnetic drum forms anelectro-mechanical transducer.One terminal of the coil 10 is connected to

the base B of a transistor which is preferablyof the Germanium junction—type, and the otherterminal of the coil 10 is connected to oneterminal of a parallel circuit incorporating aresistor 12 and a capacitor 13. The otherterminal of this parallel circuit is connected tothe negative terminal 14 of a battery or othervoltage source the positive terminal 15 ofwhich is connected to the transistor emitter E.One terminal of the coil 11 is connected to thetransistor collector C and the other terminal ofthe coil 11 is connected to the negative term-inal 14.The above circuit is a self-regulating one in

that it will cause the tines to oscillate not onlyat their natural frequency, but also at a sub-stantially constant amplitude. In practice, theamplitude of oscillation of the tines will bemaintained between such maximum and mini—mum amplitudes that the length of the strokeof reciprocation of the pawl, in a directiontangent to the ratchet wheel at the point ofengagement between the pawl and the ratchetwheel, will be at least as great as the pitch Pof each ratchet tooth but not more than 21’,so that the vibrator Will cause the ratchet wheelto be rotated at 'a rotational speed directly pro—portional to the frequency of oscillation of thevibrator.

In order to increase the aceuraey obtainablefrom the timepiece, suitable means are pro-vided for varying or pre—setting the naturalfrequency xof the vibrator. According to thepresent invention, these means are in the formof a deformable element or elements carriedeither by one tine or by both, the position ofthe center of gravity of which element or ele-ments can be adjusted relative to the axis ofoscillation of the respective tine.In the embodiment illustrated in Fig. 1, the

adjusting means for adjusting the natural fre—quency of each tine are in the form of a de-formable wire or the like 16 which is attachedat one of it's ends to the magnetic drum 8, itbeing understood, however, that the wire 16may be attached to the tine directly. The wireis capable of assuming different configurations,

two of which are shown in dotted lines at 161and 1611 wherein the center of gravity ofthe wire is spaced different distances from theaxes of oscillation 31, 41 of the tines 3, 4,respectively.

It will be understood that inasmuch as thenatural frequency of a tuning fork typevibrator is the average of the natural fre-quencies of its tines, the effective natural fre-quency of the entire vibrator can be adjustedsimply by varying the natural frequency of oneof the tines. However, by providing individualfrequency adjusting means for each tine, thenatural frequency of the vibrator can be regu-lated while maintaining the natural frequenciesof the two tines equal to each other. In thisway, no energy transfer from one tine to theother takes place during oscillation so that theefficiency of the vibrator is very high.

Also, it has been found that the frequencyenergy consumption of the vibrator may bekept exceedingly small by positioning thedrums 8 in such a manner that their centersof gravity G, when the tines are at rest, arespaced from the plane of symmetry X—X ofthe Vibrator a distance DG which is substan-tially equal to the distance D0 which the axisof oscillation of each tine is spaced from thisplane of symmetry. The wires 16 are there-fore mounted on the drums 8 in such a mannerthat irrespective of the natural frequency atwhich the tines are adjusted to oscillate, thecenter of gravity of the combined mass con-stituted by each drum 8 and wire 16, whenthe tines are at rest, is still spaced the sameJd(istagéce Du from the plane ,of symmetry

The embod-iment illustrated in Fig. 2 differsfrom the above—described one only in that eachof the wire weight elements 16 is attached atboth of its ends to one of the drums 8, withdiferent configurations of the wire beingshown at 161 and 16“.WHAT WE CLAIM IS:—1. A watch or clock having a timepiece

mechanism and a tuning—fork type vibrator fordtivmg the timepiece mechanism, wherein theyibrator and the timepiece mechanism are sointerconnected with each other that the rate atwhich the timepiece mechanism is driven isproportional to the natural frequency of oscil-lation of the vibrator, means being providedfor varying the natural frequency of thevibrator, said means being associated with atleast one tine of said vibrator and comprisinga deformable element attached to said tine,said element being capable of deformation intoany of a plurality [of differing configurations soas to vary the disposition of the centre ofgravity of said element with respect to theaxi'sof oscillation of said tine. ,, 5"»

2. A watch or clockraccor'ding to claim 1,wherein said element‘is constituted by a de-formable wire.

3. A watch or clock according to either of

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the preceding claims, wherein both tines of thevibrator are associated with said elements.

4. A watch or clock according to claim 2,wherein both ends of said wire are rigidlycoupled to the associated tine.

5. A watch 01' clock according to any oneof claims 1 to 3, wherein both tines carry ator near their free ends electrical oscillatingcomponents the centre of gravity of each ofwhich, when the tines are at rest, is spacedfrom the plane of symmetry of the vibrator thesame distance which the axis of oscillation ofthe respective tine is spaced from the saidplane of symmetry, and wherein said deform-able elements are carried either by the elec—trical oscillating components or by the tinesthemselves in a region near the respective elec—

trical oscillating component and are so con-stmcted and arranged that the centre ofgravity of the combined mass constituted byeach electrical oscillating component anddefiormable element, will, when the tines are atrest, still be spaced the same distance fromsaid plane of symmetry irrespective of thenatural frequency at which the tine is adjustedto oscillate.

6. A watch or clock substantially as herein—before described with reference to the accom-panying drawings.

HASELTINE, LAKE & CO.,28, Southampton Buildings,

Chancery Lane, London, W.C.2,Agents for the Applicants.

Leamington Spa: Printed for Her Majesty’s Stationery Office, by the Courier Ptess.—1960.Published by The Patent Office, 25, Southampton Buildings, London, W.C.2, from Which

copies may be obtained.

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828,357 COMPLETE SPECiFICATlON

I SHEET This drawing is a reproduction ofthe Original on a reduced scale.

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