US3028511A - Method for correcting the anisochronism of a timepiece, and the timepiece obtained by the application of this method - Google Patents

Description

Aprll 3, 1962 A. BEYNER 3,028,511

METHOD FOR CORRECTING THE A OCHRONISM OF A TIMEPIECE, AND THE TIMEPI OBTAINED BY THE APPLICATION OF wars METHOD Filed May 15, 1959 mum/70g N gi ATTORNEY nitd States The present invention relates to a method of at least partially correcting the anisochronism of the electromagnetically maintained oscillating regulator member of a timepiece of the type forming the subject of Patent No. 2,946,940, Beyner et al., issued July 26, 1960, that is to say, a timepiece in which the regulator member is rigid with a magnet oscillating in the neighbourhood of a ring and producing by induction, in a pick-up winding, an im pulse signal controlling the feed of a driving winding, at

the rate of one driving impulse per oscillation of the bal- I ance wheel.

The invention also concerns the timepiece obtained by the application of this method.

The regulator member of a timepiece, whether it be electromagnetically or mechanically maintained, always has residual anisochronism, regardless of the measures applied to render it isochronous. ent invention is further to reduce this residual anisochronism, or even to eliminate it, by creating by means of an action on the device by which the regulator is maintained,

a directed cause of-anisochronism such as tocornpensate at least partially for the aforesaid residual anisochromsm.

The method according to the invention is characterised by the fact that the cause of directed anisochronism is created by disposing the ring and the oscillating magnet slightly eccen-trically in relation to one another.

The timepiece according to the present inventionis characterised by the fact that the ring and the oscillating magnet are disposed slightly eccentrically in relation to one another.

The accompanying drawings, in which only the parts necessary {or an understanding of the invention are shown, illustrate by way of example two constructional forms of the subject of the invention.

FIGURE 1 is a plan view of a detail of a first constructional form of a timepiece, and

FIGURE 2 is a plan View of a detail of a second constructional form of a timepiece.

In the first constructional form, the balance wheel of the timepiece consists of a magnetised bar 1 oscillating within a ring 2, in the plane of the latter. The magnet is subjected to the action of a regulating hair spring (not shown). The ring 2 has two lugs 2a, through which there extend fixing screws 3 engaging in the plate 4 of the movement frame. The ring is intended to divide the magnetic flux of the magnet 1 into two partial fluxes 5 and 6 The ring 2 supports a pick-up winding 7 and driving winding 8 of pancake type, situated in the air gap. During the travel of the north pole of the magnet past the pick-up winding 7, a current is induced in this winding and is transmitted through an amplifier circuit (not shown) to the driving winding 8. The operation thereof is described in detail in Patent No. 2,946,940, Beyner et al.

The ring 2 is open at 9, at a point diametrically opposite the pick-up winding 7. A cam 10 rigid with a slotted control head 11 is pivotally mounted on the frame of the movement, between the two ends 2a and 2b of the ring. A spring 12in the form of an open ring, fixed to the movement plate 4 by a screw 13, acts on these The object of the presends of the ring so as to maintain them against the cam 10. Owing to this arrangement, it is possible, by manipulating the control head 11, to open or close the ring to a variable extent, thus creating between the ring and the oscillating magnet an eccentricity by which the oscillations of the magnet are magnetically affected. The anisochronism thus introduced into the oscillating systern, and which is adjustable, can at least partially compensate for the causes of anisochronism present in any oscillating regulator (balance wheel-hair spring system) of a timepiece.

Thus, by turning the eccentric 10 in such manner as to reduce the width of the slot 9', the magnet 1 is moved towards the surfaces of the ring designated 14 and 15, whereby the small arcs of the oscillating magnet are advanced. On the other hand, when the width of the slot 9 is increased, the surfaces 14 and 15 of the ring are moved away from the magnet 1, whereby the small arcs of the magnet are retarded.

The width of the slots in thering may be adjusted by means other than the cam 16 described and illustrated. Thus, it is possible to use, for example, a wedge-shaped spacer member introduced between the'ends of the ring and shifted by means of an adjustment screw. 7

The slot 9 in the ring has, in addition, the effect of reducing one of the partial magnetic fluxes of the magnet in favour of the other when the magnet occupies a position differing from its position of equilibrium as illustrated in the drawing, whereby the quality of the signal induced in the pick-up winding 7 is improved (see Patent No. 2,946,940, Beyner et al. In order that this effect may be retained, the cam 10 and the spring 12 will consist of a non-magnetic material.

In the constructional form of FIGURE 2 the ring designated 1-6 is maintained in position on the plate of the diagrammatically illustrated movement 17 by four screws 18 disposed at with respect to one another and adapted to be screwed in studs 19 fixed to the plate and bearing radially against the ring. The balance wheel also consists of a. bipolar magnet, here designated 2-0, which rotates within the ring, in the plane of the latter. By screwing or unscrewing the screws 18 to a variable extent, it is possible to produce in all directions an eccentricity between the ring 16 and the magnet 20, which eccentricity is of adjustable value. This eccentricity and its direction create by magnetic means an anisochronism ot' the oscillating member, whereby it is possible, as in the first constructional form, to compensate for the anisochronism of the adjusting system of the timepiece.

The invention is not limited to the constructional forms described and illustrated. Thus, the oscillating magnet nee-d not itself constitute the regulating balance wheel, but may be distinct therefrom. The magnet and the balance wheel will then be rotatable withone another.

What I claim is:

1. In a timepiece having an electromagnetically maintained regulator of the oscillatory type inherently prone to anisochronism, which regulator com-prises an oscillatory permanent field magnet, and a ring of material of high magnetic permeability forming air gaps with the poles of the magnet and so forming flux paths with said magnet as to divide the flux of the magnet into a number of partial fluxes equal to the number of poles of the magnet, the feature that said ring and the oscillatory magnet are disposed slightly eccentrically in relation to each other so as to produce magnetically as the result of the eccentricity and oscillation of said magnet, anisochronism in the regulator at least partially compensating for the anisochronism to which the regulator is inherently prone.

2. In a timepiece having an electromagnetically maintained regulator of the oscillatory type inherently prone to anisochronism, which regulator. comprises an oscillatory permanent field magnet, and a ring of material of high magnetic permeability forming air gaps with the poles or" the magnet and so forming flux paths with sai magne as to divide the flux of the magnet into a number of partial fluxes equal to the number of poles of the magnet, the feature that said ring has a radial air gap between adjacent ends thereof and is so disposed in forming the airgap as to introduce eccentricity between itself and the oscillatory magnet for the magnet and ring to produce magnetically as the result of the eccentricity and oscillation of said magnet, anisochronism in the regulator at least partially compensating for the anisochronism toywhich the regulator is inherently prone.

3. In a timepiece having an elcctromagne-tically maintained regulator of the oscillatory type inherently prone to anisochronism, which regulator comprises an oscillatory permanent field magnet, and a ring of material of high magnetic permeability forming air gaps with the poles of the magnet and so forming flux paths with said magnet as to divide the flux of the magnet into a number of partial fluxes equal to the number of poles of the magnet, the feature that said ring has a radial air gap between adjacent ends thereof, and said regulator includes adjusting means engaging said adjacent ends of the ring for the positions occupied by said ends relative to each other to be altered to produce slight eccentricity between said ring and the oscillatory magnet and for said ring and magnet to create magnetically as the result of the eccentricity and oscillation of said magnet, anisochronism in the regulator at least partially compensating for the aniso- "chroni-sm to which the regulator is inherently prone.

4.-ln a timepiece having an eleotromagnetically maintained regulator of the oscillatory type inherently prone to anisochronism, which regulator comprises an oscillatory permanent field magnet and a ring of material of high magnetic permeability forming air gaps with the poles of the magnet and so forming flux paths with said magnet as to divide the flux of the magnet into a number of partial fluxes equal to the number of poles of the magnet. the feature that said ring has a radial air gap anisochronism in the regulator at least partially compensating for the anisochronism to which the regulator is inherently prone.

5. in a timepiece having an electromagnetically maintained regulator of the oscillatory type inherently prone to anisochronism, which regulator comprises an oscillatory permanent field magnet, and a ring of material of high magnetic permeability forming air gaps with the poles of the magnet and so forming'fiux paths with said magnet as to divide the flux of the magnet into a number of partial fluxes equal to the number of poles ofthe magnet, the feature that said ring has a radial air gap between adjacent ends thereof, said regulator includes a rotata-bly chronism in the regulator at least partially compensating for the anisochronism to which the regulator is inherently A,

prone.

6. In a timepiece having an electromagnetically maintained regulator of the oscillatory type inherently prone to anisochronism, which regulator comprises an oscillatory permanent field magnet, and a ring of material of high magnetic permeability forming air gaps with the poles of the magnet and so forming flux paths with said magnet as to divide the flux of the magnet into a number of partial fluxes equal to the number of poles of the contact with the circumference of the ring fordisplacing the ringin the plane of the ring to produce slight eccen tricity between said ring and the oscillatory magnet and bit for said ring and magnet to create magnetically as'the result of the eccentricity and oscillation of said magnet, anisochrom'smdn the regulator at least partially compensating for the anisochronism to which the regulator is inherently prone.

References Cited in the file of this patent UNITED STATES PATENTS 2,941,417 Junghans et al. June 21, 1960 2,945,940 Beyner et al. July 26, 1960 FOREIGN PATENTS 7 569,483 Canada Jan. 27, 1959

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