EP1801667B1 - Gears for timepiece movement, mechanism and timepiece movement including said gears - Google Patents

Abstract

The gear has a drive gear (1) comprising a drive sector having identical epicyclical teeth (100) and a non-toothed positioning gear (101). The drive gear and a driven gear (2) gear with each other by their respective teeth when the gears are placed in respective predefined positions. The gear (2) comprises truncated teeth (201, 202) having free surfaces (210, 220) with shape complimentary to that of the gear (101) when the surfaces are disposed with respect to the gear (101). The teeth are arranged and numbered such that the tapered teeth of the gear (2) face the gear (2). An independent claim is also included for a driven gear for gearing a timepiece.

Description

Technical area

The present invention relates to the field of watchmaking. It relates, more particularly, to a gear intended to be implemented in a movement for a timepiece, of the type comprising a driving wheel and a toothed gear wheel capable of meshing with each other by their respective teeth. One of these two wheels can possibly take the form of a pinion. The driving wheel comprises at least a first toothed sector, driving, defining its teeth and at least a second non-toothed positioning sector, arranged at a constant intermediate level with reference to the height of the toothing.

In a preferred embodiment of the invention, the corresponding timepiece is of the type comprising a mechanism for displaying a large date, that is to say comprising respective means for displaying the units and dozens of separate dates.

State of the art

Such mechanisms are well known in the state of the art, such as the patent CH 310559 , issued October 31, 1955 on behalf of the Watchmaking Factory of Fontainemelon. This document describes a watch movement including means for displaying a large date as defined above. For this purpose, the movement comprises in particular three coaxial and rotationally fixed wheels, a first of which is driven by an element of the work-finishing train, a second driving being arranged to drive a display disc. units of the date while the third, also leading, is arranged to drive a display disk dozens of the date.

The first wheel has thirty-one teeth and is driven at the rate of one tooth per day.

The second wheel has thirty teeth of the same length and a tooth having a truncation extending to the bottom of the toothing to define an undirected sector, of length corresponding to a tooth. This wheel meshes with a pinion comprising ten teeth and secured to a disc bearing the numbers from 0 to 9. These different components of the mechanism are assembled in such a way that, when the displayed date changes from thirty-one to one month to the first the following month, the display disc units is not driven, because the toothed sector of the second wheel moves opposite the corresponding gear.

However, this mechanism has the disadvantage that, in the event of a violent impact, when the toothed sector faces the pinion, the pinion is able to turn freely, despite the typical presence of a jumper to define its angular positions. stable.

A technical solution to completely eliminate the risk of inadvertent jumping gear units is also known from the state of the art. This solution consists in providing a height of the toothed sector, intermediate with reference to the height of the toothing and, sufficient to prevent the rotation of the gear of the units of a complete step, a jumper ensuring the return of the pinion in its stable position after shock. Indeed, at the moment of impact, when the pinion rotates on itself, one of its teeth collides with the toothed sector of the drive wheel, by its tip, to limit its rotation.

Such a technical solution, although effective, has a significant disadvantage directly related to the collision mentioned above, which can lead, after successive shocks, to a deformation of one or more teeth of the driven wheel, or pinion, or even break. Of course, in such a case, the mechanism of display of the big date would be put out of service and would require a replacement of the pinion damaged by a watchmaker. In addition, if the user is slow to detect the malfunction of the display, in the case where at least one of the teeth of the pinion is broken, fragments of the latter could damage other parts of the watch movement.

Moreover, it is also known, for example from the document EP1351104 the possibility of using partially truncated teeth, to improve meshing or to obtain sequential workouts.

Disclosure of the invention

The main object of the present invention is to improve the reliability and longevity of the gears of the prior art, by proposing a technical solution making it possible to avoid accidental jumps of the display members in the event of impact, while improving the resistance mechanical gear wheel gearing involved.

To this end, the invention relates to such a gear, characterized in that the driven wheel comprises at least a first tooth truncated to have a shape substantially complementary to that of the positioning sector when it is arranged opposite the latter. Furthermore, the gearing is further characterized by the fact that the respective teeth of the driving and driven wheels are arranged and numbered in such a way that, when the toothed sector is arranged facing the driven wheel, the first truncated tooth of the latter faces him.

Thanks to these particular characteristics, the truncated tooth of the driven wheel allows rotation of the driving wheel without the first being driven while the positioning sector moves opposite the latter. In addition, the fact that the free portion of the truncated tooth is not pointed, like the head of a conventional tooth, makes it possible to limit the mechanical stresses it is likely to undergo in the event of an impact and therefore the risks of damage.

In a preferred embodiment, a gear of this type is used to display a date of the big date type, more specifically, the display of the value of the unit of that date. For this purpose, the driven wheel comprises a multiple m of ten teeth, including m first truncated teeth. The driving wheel, or wheel units, has a number of teeth equal to thirty-one times the multiple m minus (m + one) teeth, or 31 m - (m + 1), the periphery of the wheel corresponding to the length of a toothing of 31 m teeth.

Preferably, the multiple m is taken equal to two, which corresponds to fifty nine teeth for the unit wheel, the toothless sector having a length corresponding to three teeth, and twenty for the driven wheel, including two teeth truncated to present teeth. free surfaces of respective shapes substantially complementary to that of the positioning sector when they are arranged opposite the latter.

The present invention also relates to a watch movement in which such a gear is implemented, as well as a wheel meeting the characteristics of the driven wheel set out above.

Brief description of the drawings

Other features and advantages of the invention will emerge more clearly on reading the detailed description which follows, made with reference to the appended drawings presented by way of non-limiting examples and in which:

- the figure 1a is a schematic top view of a gear comprising a driving wheel and a driven wheel engaged with said driving wheel, according to a first preferred embodiment of the present invention, at a first given moment of its implementation;

- the figures 1b and 1 C respectively represent a schematic view from above of a detail of the gear of the figure 1a at a second and a third successive instants of implementation of the first embodiment, subsequent to the first instant of the figure 1a ;

- the figure 2 represents an elevational view of the wheels represented on the figure 1a when implemented in a date display mechanism of a large date type, and

- the figure 3 is an elevational view of a driving wheel and driven wheel according to a second preferred embodiment of the present invention.

Mode (s) of realization of the invention

The figures 1a , 1b and 1 C represent a schematic view of a preferred embodiment of a driving wheel 1 and a driven wheel 2, or pinion, engaged with each other, intended to equip a movement for a timepiece incorporating a date display of the large date type, at three successive times, during operation.

The driving wheel 1 comprises a drive sector, having an epicycloid-like toothing of fifty-nine identical teeth 100, and a non-toothed positioning sector 101 extending over a width corresponding to three teeth 100. The positioning sector 101 has a constant level with respect to the bottom of the toothing substantially corresponding to the height of the foot of the teeth 100. More specifically, the free portion 102 of the positioning sector has substantially the shape of an arc whose center is coincident with that of the wheel 1.

The driving wheel 1 comprises a central opening 3 intended to cooperate with a shaft or tenon (not shown) to ensure the maintenance and radial guidance.

In addition, a plurality of holes 4 is also provided in the driving wheel 1, in particular to ensure the positioning and fixing of the driving wheel on a wheel with thirty-one conventional teeth, as will be explained in connection with the detailed description of the figure 2 . The driven wheel, or pinion, 2 comprises a toothing having twenty teeth 200, two first teeth 201 and 202 are truncated at their respective heads. Second and third teeth, 203 and 204, are also truncated more significantly than the first teeth 201 and 202, their free portions being substantially rectilinear, by way of non-limiting example.

The driven wheel 2 comprises a central opening 5 intended to cooperate with a shaft or tenon (not shown) to ensure the maintenance and radial guidance.

In addition, a hole 6 is provided in the driven wheel, away from its central opening 5, which can be used to ensure its relative angular positioning with respect to a constituent element of the date display mechanism. In the configuration represented on the figure 1a , that the free portions 210 and 220 of the first truncated teeth 201 and 202 have curved shapes special. Indeed, these free portions are preferably shaped so as to substantially match the shape of the free portion 102 of the positioning sector 101.

Thus, from this configuration, if the driving wheel 1 rotates clockwise, the positioning sector 101 moves opposite the driven wheel 2 without coming into contact with the latter which is not driven. The driving of the driven wheel 2 resumes when the tooth 100 situated immediately after the positioning sector 101 comes into contact with the first tooth 202 of the driven wheel, after having passed opposite the tooth 204 without having interacted with it.

It appears from the figure 1a , that thanks to the particular shapes of the first teeth 201 and 202 of the driven wheel 2, the risk of inadvertent jumps of the latter is removed in the event of shock occurring while the positioning sector 101 is located opposite the driven wheel.

These teeth having free portions 210 and 220 of shapes complementary to that of the free portion 102 of the positioning sector 101, while being very close to the latter. The possible angular displacement of the driven wheel 2 in this situation is very small.

Indeed, we see that, in the configuration represented on the figure 1a if the driven wheel 2 were to turn counterclockwise due to a shock, the tooth 201 would immediately abut the positioning sector 101 to prevent it from turning. Conversely, if the driven wheel 2 were to rotate clockwise following a shock, the tooth 202, disposed opposite a recess 103 of the toothing adjacent to the positioning sector, would abut against the edge of the sector of positioning 101 to prevent it from turning. Thus, the portions of the driven wheel capable of colliding with the driving wheel 1 have a shape that makes it possible to limit the risks of damage compared to a conventional toothing with which the shocks are located at the level of the tooth tips, particularly fragile.

These characteristics give the gear, according to the present embodiment of the invention, significant qualities compared to the gears of the prior art, in terms of reliability and durability.

Note that according to the present embodiment, the driving wheel 1 which has fifty nine teeth is intended to be driven by a wheel thirty-one teeth advancing one step per day. Thus, at each step of the wheel with thirty-one teeth, commonly called thirty-one wheel, the driving wheel 1 takes a pitch of two teeth 100. Likewise, a step of the driven wheel 2 corresponds to an angular displacement of 200 teeth. For this reason, and according to the particular respective dimensions of the driving wheels 1 and 2 led of the figure 1a it is intended to truncate the teeth located on either side of the first two teeth 201 and 202. Thus, the second and third teeth 203 and 204 are truncated to be clear of the bearing surface of the driving gear 1, when the teeth 201 and 202 are arranged opposite the latter.

Before being in the configuration of the figure 1a during the preceding step, the last tooth 100 of the driving wheel, adjacent to the toothed sector 101, has moved in the anti-clockwise direction of this wheel, starting from the vicinity of the truncated tooth 201, passing in front of the second truncated tooth 203 without driving it. At the same time, the toothed sector 101 has moved in front of the first truncated teeth 201 and 202 without coming into contact with them until the first tooth 100 of the driving sector of the driving wheel 1 comes into contact with it. the first truncated tooth 202, as shown on the figure 1 at. This latter operation takes place without rotation of the driven wheel, because of the truncation formed on the third tooth 204 so that it is located out of reach of the toothing of the driving wheel.

As just stated above, at any moment of this displacement, the driven wheel 2 is secured in rotation, from the point of view of a possible impact that would tend to rotate it.

When the driving wheel 1 continues its rotation, under the effect of its connection with the thirty-one wheel, the first tooth 100 of the sector drive exerts a force on the first truncated tooth 202 causing the driven wheel 2 to rotate in a clockwise direction, as shown in FIG. figure 1 b.

The rotation of the driving wheel causes a displacement of the recess 103 relative to the driven wheel, which frees the passage, in rotation, for the first truncated tooth 201.

The third truncated tooth 204 is then positioned between the first and second teeth 100 of the drive sector, as shown in FIG. figure 1c before being driven by the second of these teeth 100 and that the wheels 1 and 2 mesh in a conventional manner with their teeth 100 and 200. In this figure, it can be seen that the truncated teeth 201 to 204 exhibit a sufficient height to allow their normal training by the teeth 100.

Furthermore, it appears that the level of the positioning sector, relative to the bottom of the teeth of the driving wheel, is such that the operation of the gear can be blocked if the positioning sector is located next to teeth 200 at one time or another cycles of rotation of the wheels 1 and 2.

Thus, it is necessary that the respective teeth of the driving and driven wheels are such that, when the toothed sector 101 of the drive wheel is arranged facing the driven wheel, the first truncated teeth 201 and 202 of the latter face him . In other words, it is necessary that the period of rotation of the driving wheel is equal to, or is a multiple of, the period of rotation of the driven wheel.

In the present case, the gearing being intended to be implemented in a date indication mechanism such as that shown in FIG. figure 2 , As an illustration, the driven wheel is mounted coaxially and secured to a disk 20 bearing the numbers from 0 to 9, defining ten steps for the rotational movement of the disk and, provided to display the unit of the value of the date.

The driven wheel 2 is furthermore integral with a star 21 which is coaxial with it and on which the end of a jumper 22 ensures the stability of certain predefined angular positions of the disc 20. The latter bearing ten digits, he must perform a complete turn on himself in ten steps. The star 21 comprises, for this reason, ten teeth between which it is expected that the end of the jumper comes to be housed to stabilize the ten angular positions thus defined. The driven wheel 2 must have a number of teeth 200 which is a multiple of ten for a number of whole steps of the driven wheel to correspond to a whole number of steps of the disc 20.

It also appears from the figure 2 that the disc 20 has a slot 23 for effecting a visual angular indexing on the angular position of the star 21 or the driven wheel 2. The fact that this indexing mark takes the form of a slot also makes it possible to use a tool adapted to adjust the angular position of the disc 20 by acting directly at the mark.

As mentioned above, the driving wheel 1 is mounted coaxially and secured to a wheel of thirty-one teeth 24, or thirty-one wheel, intended to be driven by a clockwork finishing work train, by the intermediate of a clockwork. The wheel of thirty-one makes a complete turn on itself in thirty-one days, advancing one step per day, usually at the end of the day. Because of its connection with the thirty-one wheel, the driving wheel also turns on itself in thirty-one days.

As it stands out better from the figure 1a , the driving sector of the driving wheel 1 has fifty nine teeth. This number indeed makes it possible to fulfill the condition, stated above, concerning the necessary multiplicity of the period of the driving wheel 1 relative to that of the driven wheel 2.

Thanks to these characteristics and, by providing a particular arrangement of the disk 20, known from the state of the art, the drive thereof occurs thirty times in thirty-one days, the driven wheel 2 is not driven by the driving wheel 1 during the passages of the thirty-first day of a given month to the first of the following month, due to the displacement without drive of the positioning sector facing the teeth of the driven wheel.

In addition, on the figure 2 , that the date indication mechanism comprises a second disk 25 indicating the value of the ten days of the date and carrying for this purpose the numbers from 0 to 3. A pinion 26 with eight teeth is mounted coaxially and secured to the disk 25 to ensure his training. The pinion is arranged to mesh with a tens wheel 27 mounted coaxial and integral with the thirty-one wheel 24. The tens drive wheel 27 has four teeth spaced so as to cause a rotation of a step two teeth of the disk 25 during the changes of ten of the date value, similarly to what is described in the prior art.

It may be noted that a second jumper 28 acts on the pinion 26, while a third jumper 29 acts on the thirty-one wheel 24, to ensure the positioning of their respective stable angular positions.

The entire mechanism that has just been described is intended to be mounted on a watch movement platen or on a complication module, in a conventional manner.

The figure 3 represents, in a perspective view, a second preferred embodiment of the present invention.

In this implementation, the driving sector of the driving wheel 31 has a tooth-like to edge, that is to say located outside the plane of the wheel board. The operating principle of this device is identical to that described in relation to the figures 1a , 1b and 1 C .

It can be seen that the positioning sector 32, toothless, of the driving wheel 31 has a free surface 33 situated at a constant intermediate level with reference to the height of the toothing, as well as in the first embodiment. Thus, this free surface 33 is flat, insofar as the bottom of the teeth of the drive sector describes a ring contained in a plane parallel to the plane of the wheel plank, while it described a ribbon in the previous mode .

As a result, the first truncated teeth 41 and 42 of the driven wheel 40 have planar free portions 410 and 420 so as to conform to the shape of the positioning sector 32 when it is arranged opposite them. As in the first embodiment, the driven wheel 40 includes second and third teeth 43 and 44 truncated to a degree allowing them to be located out of reach of the teeth of the driving wheel when the first and second teeth truncated 41 and 42 are positioned opposite the driving wheel.

The foregoing description attempts to describe particular embodiments by way of non-limiting illustration and the invention is not limited, for example, to the number of teeth of the wheels described, to the application mentioned in FIGS. date display mechanisms, or to wheels whose teeth only describe a single segment. In particular, it is possible to provide that the driving wheel comprises a plurality of drive sectors separated from one another by a plurality of positioning sectors, without departing from the scope of the present invention.

Moreover, the notion of wheel is to be interpreted in the broad sense. In particular, as mentioned above, at least one of the wheels may take the form of a pinion or a ring gear. In particular, it could also be provided that the driving wheel is a ring gear with internal teeth, the driven wheel then being located inside the driving wheel.

Likewise, the invention is not limited to the number of teeth contributing to the gearing of the two wheels and is applicable to a gear in which one, two or more teeth of each of the wheels are involved in the transmission of the movement. . Depending on the case, the skilled person will not encounter any particular difficulty to adapt the number of truncated teeth on each wheel, and the shape of their truncations. More specifically, the latter may for example be made in such a way that the free portions 210 and 220 of the teeth 201, 202 are flat. The relative heights of the toothing and the toothed sector have also been mentioned as non-limiting indicative and may be modified without departing from the scope of the present invention.

It should also be noted that the additional truncated teeth may be omitted depending on the number of teeth contributing to the gearing, the respective dimensions of the two wheels, or the spacing provided between the wheels according to their respective dimensions, therefore their penetration.

Claims (11)

1. A gear for a clockwork movement including a toothed driving gear (1, 31) and driven gear (2, 40) able to mesh with one another via their respective toothings, said driving gear including at least one first toothed driving sector, defining said toothing and at least one second non-toothed positioning sector (101, 32), arranged at a constant intermediate level relative to the height of said toothing,
   characterized in that said driven gear comprises at least one first truncated tooth (201, 202, 41, 42) to have a free surface (210, 220) with a shape substantially complementary to that of said positioning sector (101, 32) when it is arranged opposite the latter, and in that said respective toothings are arranged and numbered so that, when said non-toothed sector of said driving gear is arranged opposite said driven gear, said first truncated tooth (201, 202, 41, 42) of the latter faces it.
2. The gear according to claim 1, characterized in that
   said driving gear (1, 31) and said driven gear (2, 40) can mesh with each other by at least two teeth (100, 200, 201 to 204) of their respective toothings, when the latter are arranged in predefined respective positions, and
   in that said driven gear also comprises a second truncated tooth (203, 43) adjacent to and upstream of said first truncated tooth (201, 202, 41), relative to the direction of rotation of said driven gear, said second tooth being truncated so as to be situated out of reach of the toothing of said driving gear when said first and second truncated teeth are positioned in said predefined position.
3. The gear according to claim 2, characterized in that said driving gear (1, 31) and said driven gear (2, 40) can mesh with each other by at least three teeth of their respective toothings, when the latter are arranged in predefined respective positions, and
   in that said driven gear also comprises a first additional truncated tooth (202, 42) also adjacent to said first truncated tooth (201, 41) and having a free surface (220) with a shape substantially complementary to that of said positioning sector (101, 32) when it is arranged opposite the latter.
4. The gear according to claim 2 or 3, characterized in that said driven gear comprises a third truncated tooth (204, 44) arranged downstream of that (202, 42) of said other truncated teeth that is situated the furthest downstream, relative to the direction of rotation of said driven gear, said third tooth (204, 44) being truncated so as to be arranged out of reach of the toothing of said driving gear when said first truncated teeth (201, 202, 41, 42) are arranged in said predefined position.
5. The gear according to any one of the preceding claims, characterized in that said positioning sector (101) has a free surface, which can be arranged opposite said driven gear, which generally has the shape of a cylinder portion.
6. The gear according to any one of claims 1 to 4, characterized in that one of said toothings is a contrate toothing.
7. The gear according to claim 6, characterized in that said contrate toothing is that of said driving gear (31), and
   in that said positioning sector (32) has a free surface, which can be arranged opposite said driven gear (40), having a generally flat shape.
8. The gear according to any one of the preceding claims, intended to be implemented in a mechanism for displaying a date, characterized in that the toothing of said driven gear (2, 40) includes a multiple m of ten teeth (200, 201 to 204), while the toothing of said driven gear (1, 31) includes 31 m-(m+1) teeth (100).
9. A mechanism for indicating a date of the large date type intended to be driven by a clockwork movement going train, and comprising a gear according to any one of the preceding claims, a mobile organ (20) for indicating the unit of said date driven by said driven gear (2) as well as means (25, 26, 27) for indicating the tens of said date.
10. A timepiece movement comprising a going train arranged to drive a mechanism for indicating a date according to claim 9.
11. A timepiece comprising a movement according to claim 10 and at least one opening able to make the indication of the date of the major date type visible.

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