US3537326A - Device for transforming oscillating movement into rotational movement in particular for timepieces - Google Patents

Description

3,537,326 ENT INTO .7 M. HETZEL' DEVICE FOR TRANSFORMING OSCILLATING MQVEM ROTATIONAL MOVEMENT IN PARTICULAR FOR TIMEPIECES Filed July 5, 1968 INVENTOR: MAX HETZEL By; 6? M;

Attorney United States Patent Oflice 3,537,326 Patented Nov. 3, 1970 3,537,326 DEVICE FOR TRANSFORMING OSCILLATING MOVEMENT INTO ROTATIONAL MOVEMENT IN PARTICULAR FOR TIMEPIECES Max Hetzel, Bienne, Switzerland, assignor to Centre Electronique Horloger S.A., Neuchatel, Switzerland, a company of Switzerland Filed July 5, 1968, Ser. No. 742,833 Int. Cl. F16h 27/00 US. Cl. 74-142 7 Claims ABSTRACT OF THE DISCLOSURE This disclosure is concerned with a device for transforming oscillating movement into rotational movement of the type in which a gear is driven by at least one pawl, wherein the gear is at least partially made of a magnetic material of high coercivity, and has poles for magnetically driving a second wheel.

This invention is concerned with a device for transforming an oscillating movement into a rotational movement; and in particular, this application discloses an improvement over my copending application now issued as US. Pat. 3,451,280.

In an electromechanical watch which has a mechanical resonator driving the gear train of the watch through a device for transforming oscillating movement into rotational movement by means of at least one pawl driving a pawl wheel, it has already been proposed to replace the usual toothed pinion of the pawl wheel by a magnetic pinion magnetically driving the first wheel of the gear work.

This device for transforming movement has the advantage to be of a great simplicity, of eliminating to a large measure power losses due to friction and of constituting an excellent mechanical filter insulating the resonator from the gear train. In addition, its relative position to the magnetic pinion and to the driven wheel only require a precision which is far less than that of the gears of a mechanical gear work which makes possible a completely independent manufacture. On the one hand the manufacture includes the oscillator with its device for transforming movement comprising the pawl, the ratchet wheel and the polar wheel; and, on the other hand, the manufacture includes the gear work mounted on the plate and comprising the driven wheel, and the subsequent assembly without difiiculty of these two parts.

Starting with this driving method, the present invention has for its object a device for transforming an oscillating movement into a rotational movement in particular for timepieces and comprising a toothed wheel driven by at least one pawl, and characterized mainly by the fact that the said toothed wheel is at least partially of magnetic material at high coercivity, has poles and magnetically drives a second wheel.

The elimination of the pawl wheel combined with a magnetic pinion makes possible a simple construction, the reduction in height of the shaft carrying the magnetic toothed wheel which leads to a pawl modulus of diminished thickness. This construction also specially has for an advantage to decrease the inertia of the modulus driven by the pawl.

The accompanying drawing represents, by way of a nonlimiting example, one embodiment of the subject of the invention.

FIG. 1 shows a plan view thereof and FIG. 2 an elevational cross sectional view.

The device shown in the drawing is constituted by a toothed ring 1 with triangular teeth of magnetic material having very high coercivity, for example a platinumcobalt alloy having 6 poles alternating along its periphery. This ring is secured on a shaft 2 pivoted between two sets of stones 3, 4 and 5, 6 fixed in two bridges 7 and 8, for example, the bridges of a modulus secured on the opposite faces of a resonator 13, more exactly on its foot.

Wheel 1 is driven by pawl 9, pawl 10 being a return pawl. The pawls can also both be driving pawls.

Wheel 1 magnetically drives a wheel 11 of greater diameter whose pinion 12 meshes with the next wheel of the gear work. Wheel 11 is magnetized in order to have alternate poles along its circumference, the spacing of these poles being approximately equal to the spacing of the poles of wheel 1.

In order to reduce to the minimum the inertia of wheel 1, whose regular movement is a source of perturbations and loss of power, its diameter is very small, in this case equal to 0.5 mm. For a thickness of 0.1 mm, there is thus obtained, for a wheel of cobalt-platinum, a moment of inertia of the order of 10-7 gr. cm The number of teeth is reduced in consequence to 36.

Wheel 11 is smooth, but it also can have projecting poles. It can also be constituted by a ring of high coercivity magnetic material such as a cobalt-platinum alloy mounted on a core of nonferromagnetic material, such as brass, which economizes magnetic material. In a less expensive modification, wheel 11 can be made of a ferronickel alloy or even of soft iron.

The pierced stone 3 and the counter-pivot stone 4 are additionally transparent in order to facilitate observation of the beaks of the pawls in order to check their position and the adjustment of their phases.

What is claimed is:

1. A device for transforming oscillating movement into rotational movement, especially for timepieces, comprising at least one pawl, a toothed wheel driven by said pawl, said toothed wheel being at least partially of magnetic material at high coercivity and having a plurality of circumferentially spaced poles, and a second wheel magnetically driven by said toothed wheel.

2. Device according to claim 1, wherein said toothed wheel consists of a ring mounted on a shaft, said ring having a diameter approximately twice that of said shaft.

3. Device according to claim 1, wherein said second wheel is toothed and made of soft iron.

4. Device according to claim 1, wherein said second wheel is a polar wheel.

5. Device according to claim 2, having a second toothed wheel constituted at least in part by a ferro-magnetic material.

6. Device according to claim 4, having a second wheel constituted by a high coercivity magnetic ring mounted on a nonmagnetic core.

7. A device for transforming oscillating movement into rotational movement, especially for timepieces, comprising a toothed wheel driven by at least one pawl; said toothed wheel is formed at least partially of magnetic material at high coercivity, has a plurality of poles for magnetically driving a second wheel, and is mounted on a shaft; a transparent bearing in which at least one of the extremities of said shaft is mounted, said bearing being of sufficient dimensions for observing the cooperation of said pawl with said toothed wheel.

RICHARD B. WILKINSON, Primary Examiner E. C. SIMMONS, Assistant Examiner US. Cl. X.R.

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