EP2339410B1 - Dynamometric device indicating the torque lead of a timepiece barrel - Google Patents

Description

The invention relates to the field of watch mechanisms driven by one or more springs wound by a winding crown or an automatic winding rotor, or the like.

More specifically, the invention relates to a watch torque torque reserve torque gauge device, which comprises a turntable, a barrel, and a barrel ratchet arranged to cooperate with a ratchet catch to maintain accumulated, in a spring that includes said barrel, the mechanical energy stored by the latter, said ratchet pawl pivotable about a ratchet pivot axis, between a meshing position in which at least one tooth of said pawl cooperates with said ratchet, and a disengagement position in which each tooth of said pawl fades before rotation of the ratchet during an arming maneuver of said barrel, said ratchet pawl being biased towards said ratchet under the action of a ratchet spring of ratchet.

A spiral spring, in particular a mainspring, is a mechanical member whose response is not linear as a function of time. The torque curve delivered as a function of the number of revolutions of the spring, is a hysteresis curve between the arming curve and the disarming curve, and whose variations are sudden at the end of arming and at the end of disarming, while they are closer to a linear response in an intermediate domain, distant from one or two turns of the end of arming, respectively from the end of disarming. It is therefore useful for the user to know, at the same time, the torque reserve of the barrel spring or springs that comprises its mechanism, and also the optimum zone, corresponding to the intermediate range mentioned above, during which the operation of the clock mechanism is the most regular and the most accurate. Of course, it is advisable to draw the attention of the user to avoid an excessive reassembly which can damage a spring at the end of arming.

The estimation of the power reserve is an old concern. We know from the document FR 321 499 , or, similarly, by the patent US 623,158 , a mechanism comprising a wheel corresponding to the theoretical running time. This wheel has a dowel at a point of its circumference, corresponding to the threshold chosen to reveal a winding signal using a linkage. Similar devices are known from patent documents FR 382 836 , DE 96 562 , DE 109 388 , or DE 319478 .

Other devices, such as those known from patent documents FR 942,026 , DE 132 789 , or DE G 77 11 670.2 , trigger the appearance of a mechanical signal according to the achievement of a given position by the outer turn of the mainspring. The document DE 14 02 862 also describes the drive by the mainspring after a theoretical unwinding time.

These devices based on the good theoretical operation of the clockwork mechanism and its mainspring are not sufficient, because they do not take into account a possible relaxation of the mainspring, nor a fouling of the gear, or any phenomenon likely to alter the progress of the mechanism.

The document DE 225 092 describes an improved indicator mounted on a pivoting arm about a pivot axis integral with the plate, the pivoting arm carrying the axis of the ratchet pawl. This pivoting arm has a nose driven by a tooth rotated by the barrel drum.

It therefore seemed preferable to be interested, no longer in a theoretical position of spring or wheel, or any similar device counting a theoretical time past, but a reserve of actual torque of the mainspring, which is sufficient to drive the clockwork mechanism, both for the required time, and especially with a sufficient level of accuracy. Indeed, it is known that the end-of-arming ranges, as well as the end of disarming, of the mainspring, are areas to be avoided, due to an over-solicitation of the mechanism in the first case, and of insufficient precision in both cases.

The patent DE 181 980 proposed an innovative solution to this problem by introducing into the mechanism a compensation spring. The ratchet of the barrel cooperates, in known manner, with a pawl mounted on a ratchet support. The latter is pivotally mounted about a pivot axis which is attached to the plate of the movement. A helical compensating spring is attached, on the one hand to the plate, and on the other hand to the pawl support, which supports an indicator or is directly connected to such an indicator. During the winding of the mainspring, the compensating spring is stretched under the effect of the pressure of the mainspring, and therefore the ratchet, on the pawl. The latter therefore subjects the ratchet support, which supports one end of the compensation spring, to a pivoting torque about its pivot axis. When disarming the barrel spring, the pressure of the ratchet on its pawl decreases, which gradually relaxes the compensation spring, to a winding alarm position, visualized by the indicator. This device is a clear progress over the achievements of the prior art, but has been little used, because of the weakness of the helical compensation spring and its lack of repeatability.

We also know documents EP 1 136 892 A1 and DE 20 2008 000035U1 torque gauge torque watch momentum torque indicator devices.

It is understood that there are, thus, some devices capable of providing a good indication of the power reserve, or, better, the torque reserve of the mainspring. However some bring a disruption to the operation of sensitive organs, for example those having a needle connected to the exhaust spring. In general, all the known devices are complex, and incorporate many additional components of unit cost sometimes high, and requiring a meticulous assembly time consuming. And most importantly, they consume a large volume that, therefore, is not available for other complications, which limits the possibilities and performance of the timepiece.

In short, the object of the invention is to propose a simple and compact device, with a very small number of components, giving with good reliability to the user the indication of the reserve of torque available at the level of the mainspring. The components must be at least as reliable as the other components of the timepiece, and their implementation must not weaken any of these.

For this purpose, the invention relates to a timepiece comprising a torque gauge torque watch moment reserve device as defined by claim 1.

• la figure 1 représente, de façon schématisée, partielle, et en vue en plan par rapport à un mécanisme horloger représenté de façon partielle, un dispositif indicateur selon l'invention dans une position de désarmage;
• la figure 2 représente, de façon analogue à la figure 1, le même dispositif dans une position d'armage intermédiaire ;
• la figure 3 représente, de façon analogue à la figure 1, le même dispositif dans une position d'armage maximum.

Other features and advantages of the invention will appear on reading the description which follows, with reference to the appended drawings in which:

• the figure 1 represents, schematically, partially, and in plan view with respect to a watch mechanism partially shown, an indicator device according to the invention in a disarming position;
• the figure 2 represents, in a similar way to figure 1 the same device in an intermediate arming position;
• the figure 3 represents, in a similar way to figure 1 , the same device in a maximum arming position.

The invention relates to the field of watch mechanisms driven by one or more springs wound by a winding crown or an automatic winding rotor, or the like.

The invention more particularly relates to a dynamometric device 100, designed as a torque reserve indicator. barrel of timepiece. This timepiece, not shown in detail in the figures, comprises, in known manner, at least one plate P, at least one barrel, and at least one barrel ratchet 2. This barrel ratchet 2 is arranged to cooperate by its teeth 2a with a ratchet pawl 3 to maintain accumulated in a barrel spring that includes the barrel mechanical energy transmitted to the spring during its arming. The barrel spring is conventionally armed or reassembled by a winding crown and / or by at least one winding rotor in the case of a self-winding movement. The ratchet pawl 3 is pivotally mounted about a ratchet pivot pin 10 fixed to a support 12. The pawl 3 is movable between a meshing position and a disengaging position. The engagement position of the pawl 3 is that in which at least one tooth 31 of the ratchet pawl 3, at an end opposite this pawl pivot pin 10, cooperates with one of the teeth 2a of the ratchet of the barrel 2 for the ratchet immobilize in the direction of disarming. The detent position of the pawl 3 is the one in which each tooth 31 that the ratchet pawl 3 erases in front of the toothing 2a and allows the rotation of the barrel ratchet 2 during a winding operation of the barrel. The ratchet pawl 3 is permanently biased towards the barrel ratchet 2 under the action of a ratchet spring 4. This ratchet catch spring 4 is preferably a flat leaf spring, having a fixed first end. 11 relative to a support, and a second free end of the opposite side. Preferably, a stop (not shown) limits the stroke of the ratchet pawle 3 opposite the barrel ratchet 2, and a stop (also not shown) limits the stroke of the free end of the ratchet spring 4 on the side of the barrel ratchet 2. Advantageously, these stops are combined and constituted by a single component fixed on the support 12.

According to the invention, the dynamometric device 100 comprises a spring blade 1, a first end of which is fixed rigidly to the plate P or at a fixed point relative to the latter, by at least one, preferably at least two points fastening 7, by screw, pin, or the like. The spring blade 1 preferably extends in a plane parallel to that of the barrel ratchet 2, and comprises, in its middle part, an elastic arm 8 capable of flexing under the action of the disarming torque of the mainspring spring like this will be explained in more detail below. The ratchet support 12, which supports the ratchet pivot pin 10, is constituted by the elastic arm 8 or is fixed thereto. Preferably, the support 12 constitutes the second end of the spring blade 1 which is opposite to the attachment points 7.

The dynamometric device comprises, preferably in the vicinity of this second end of the elastic arm 8, opposite to the first attachment end to the plate, a needle 6 designed able to visualize the torque reserve of the cylinder, in cooperation with a graphical scale or graduated which constitutes a barrel torque reserve indicator 5.

Preferably, the elastic arm 8 is substantially radial with respect to the axis of revolution of the barrel ratchet 2, its second end being directed outwards.

In order to easily view the user the preferred areas for a good operation of the timepiece, the indicator needle 6 is movable in front of the torque reserve indicator 5, which comprises a graphic or graduated scale that includes said platen or a bridge fixed thereto, and which successively displays the torque available at the outlet of the barrel during the disarming of the mainspring, here between two pins 50 and 51.

To further simplify the mechanism, the flat ratchet catch spring 4 is fixed, at its first fixed end 11, to a support which is constituted by the support 12 of the ratchet catch 3.

Preferably, the leaf spring 1 is integral and incorporates the elastic arm 8 and the ratchet support 12.

The elastic arm 8 is movable between an arming position where the resisting torque that it exerts on the ratchet is equal to the maximum torque exerted by the barrel spring which is fully armed, and a disarming position which corresponds to its equilibrium position where it exerts a zero torque on said ratchet and where the mainspring is completely disarmed. This arm 8 is flexible between these two positions, the stiffness of the arm can vary to allow to display the available torque on a more or less extended scale.

Preferably, the elastic arm 8 is fixed on a fixed bridge of the plate around a fixed point located in the vicinity of the axis of the barrel ratchet 2, and is deformed in a plane parallel to that of the barrel ratchet 2 under the action of a torque exerted by said mainspring.

The winding of the mainspring is effected in the direction of the arrow A, as is visible in the figures, namely in the counter-clockwise direction. It will be understood that, the more the barrel spring is being armed, the more torque there is in the barrel ratchet 2. This torque is exerted during the rotation of the barrel ratchet 2 in the clockwise direction in the case of the figures. on the toothing 31 of the ratchet catch 3. The latter may have only one tooth 31, and remain very economical, unlike many power reserve indication systems where the ratchet is a complex piece, comprising at least a toothed sector, and is much more expensive. The higher the torque exerted on the tooth 31 of the ratchet pawl 3, the more the spring blade 1, and in particular the elastic arm 8 which is its thinnest and most deformable part, bends under the effect of this torque. An approximate representation, on figures 2 and 3 , assimilates this deflection to an angular deflection, of an angle α, of the elastic arm 8, with respect to a position of equilibrium materialized by a radial direction D. The attachment points 7 preferably extend in another direction D orthogonal to the latter. In fact, it is understood that the deflection of the leaf spring 1, which occurs in the clockwise direction in the case of the figures, is distributed over its length. The effect of this deflection is a displacement of the needle 6 with respect to the torque reserve indicator 5.

The figures illustrate a preferred example in which the equilibrium position of the spring blade 1 is the disarming position, and where all other positions of the blade spring 1 are armed positions.

It will be understood that the torque reserve indication is thus, as a dynamometric reference with respect to a flat spring, which is extremely robust, inexpensive, and compact, and that the dynamometric device 100 according to the invention does not depend in any way on the winding mode, either by a winding crown or by an automatic winding rotor.

Claims (8)

1. Timepiece including a dynamometric device (100) indicating the remaining barrel torque in said timepiece, which includes a plate, a barrel and a barrel ratchet (2) arranged for cooperating with a ratchet click (3) to keep, in a spring located inside said barrel, the mechanical energy stored by the latter, said ratchet click (3) being able to pivot about a click pivot pin (10), between a meshed position wherein at least one tooth (31) of said ratchet click (3) cooperates with said barrel ratchet (2), and a disengaged position wherein each tooth (31) of said ratchet click (3) withdraws when the barrel ratchet (2) rotates, as said barrel is being wound, said ratchet click (3) being returned towards said barrel ratchet (2) under the action of a ratchet click spring (4), said device being characterized in that it includes a strip spring (1) including a resilient arm (8) a first end of which is rigidly secured to said plate or to a fixed point relative thereto, and in proximity to a second end of said resilient arm (8) opposite to said first end, an indicator member (6) for displaying the barrel torque reserve, in conjunction with a graphic or graduated scale characterized in that said click pivot pin (10) is mounted on a click support (12), which is formed by said resilient arm (8) or fixed thereto.
2. Timepiece according to claim 1, characterized in that said resilient arm (8) is substantially radial relative to the axis of revolution of said barrel ratchet (2).
3. Timepiece according to claim 1 or 2, characterized in that said click support (12) includes, opposite said resilient arm (8), an indicator hand (6) forming the mobile indicator member in front of a graphic or graduated scale (5) on said plate or a bridge secured thereto, and which displays the torque available at the barrel output.
4. Timepiece according to any of the preceding claims, characterized in that said ratchet click spring (4) is secured, at an end (11) opposite to the end resting on said ratchet click (3), to said click support (12).
5. Timepiece according to any of the preceding claims characterized in that said strip spring (1) is in a single piece and incorporates said resilient arm (8) and said click support (12).
6. Timepiece according to any of the preceding claims, characterized in that said resilient arm (8) is arranged to be mobile between a winding position where the resistant torque said arm exerts on said barrel ratchet (2) is equal to the maximum torque exerted by said mainspring when completely wound, and an unwinding position which is the position of equilibrium thereof where said arm exerts zero torque on said barrel ratchet (2) and where said mainspring is totally unwound.
7. Timepiece according to any of the preceding claims, characterized in that said resilient arm (8) is secured to a bridge integral with said plate about a fixed point located in proximity to the arbour of said barrel ratchet (2), and is arranged to be deformed in a parallel plane to that of said barrel ratchet (2) under the action of torque exerted by said mainspring.
8. Timepiece according to any of the preceding claims, characterized in that said ratchet click (3) includes a single tooth (31).

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