Patent Application
20220155728
The invention relates to an elastic holding member for fixing a timepiece component on support elements of different types such as a balance shaft or a stub axle.
The invention also relates to an elastic holding member-timepiece component assembly and assemblages comprising such an assembly and a support element.
Finally, the invention relates to a horological movement comprising at least one of these assemblages as well as to a timepiece comprising such a movement.
In the prior art, elastic holding members are known such as timepiece collets which participate in assemblages of spirals on shafts or balance axles of regulating members such as resonators of horological movements, by elastic clamping. Such spirals are conventionally each wound around a spiral axis while being provided with a collet at their inner end. This collet includes an opening, the inner face of which comprises holding parts which are arranged to cooperate with a shaft of revolution about said spiral axis, contributing to the centring of said spiral on such a shaft.
Before making such assemblages, it is common carry out measurements of the torque and/or stiffness of these spirals, in particular during an operation called classification operation. For this purpose, the collet of a given spiral is then driven on a stub axle of circular cross section which helps to ensure that it is held in an angular and vertical position. The diameter of this stub axle is defined according to the diameter of the opening of the spiral collet, so that holding this collet in angular and vertical position, when measuring the torque of the spiral, is obtained by clamping this collet on this stub axle. Such clamping, which results from the elastic deformation of the collet, has a value defined according to the diameter of the stub axle. Subsequently, once the classification operation has been completed, the spiral collet is then separated/released from the stub axle in order to be assembled by driving it onto the balance shaft so that the parts holding the balance collet cooperate with this balance shaft in order to ensure elastic clamping.
However, such a classification operation can be at the origin of “product defects” due to the fact that it happens that the collet breaks/crumbles during multiple and repetitive stresses related to its driving, release on/from the stub axle and then a “re-driving” on the balance shaft, or else during the operation of the resonator wherein it is comprised, in particular during the movement. Indeed, during the classification operation, the clamping carried out between the stub axle and the collet causes shearing forces which can damage this collet by causing micro-breaks at least at one edge of this collet. In other words, driving this collet, conventionally made of a very fragile material under mechanical stress such as silicon, on the stub axle can generate tensions in the material of this spiral and generate a risk of crumbling which can turn out to be very critical because inducing the starting point of rupture at the collet with a risk of breakage thereof which will be detected later when it is moved.
The purpose of the present invention is to alleviate all or part of the disadvantages mentioned above by providing an elastic holding member comprising several specific holding parts each provided to cooperate exclusively with a given type of support element and in particular with the peripheral wall of this support element when mounting this member on the latter.
To this end, the invention relates to an elastic holding member for fixing a timepiece component on support elements of different cross section, comprising an opening into which each support element can be inserted, the holding member including structural elements together forming the body of this holding member and helping to ensure mounting of each support element in said opening each of these structural elements comprising a first structural sub-element and a second structural sub-element, the first structural sub-element including a volume of material greater than the volume of material constituting the second structural sub-element, the holding member comprising a connecting portion ensuring the mounting of each of said support elements in the holding member, said portion being defined on an inner face of said first structural sub-element.
Thus in this holding member the same connecting portion of a first structural sub-element of each structural element of the holding member thanks to its features, is stressed both during the mounting of this member on the stub axle and when driving said member onto a support element such as the balance shaft, regardless of the geometric shape of the cross section of this support element. In addition, the connecting portions of the first structural sub-elements of such a holding member allow to assemble this member on the stub axle by carrying out a fitting and a coupling of this holding member with this stub axle, without this mounting requiring a driving operation as is the case in the prior art. This fitting provides for the positioning of this holding member in an angular and vertical position on the stub axle, in particular when measuring the torque of a spiral, without elastic clamping, that is to say without deformation of the structural elements, namely without deformation of this holding member. In other words, such a coupling between the holding member and the stub axle necessary for carrying out the classification operation, is obtained without elastic clamping, thanks in particular to the complementarity of their shape which thus allows cooperation between the latter when they are rotated when performing the classification operation, and also thanks to the distribution of the volume/amount of material between the first and second structural sub-elements of each structural element constituting this holding member. It is therefore understood that when performing a classification operation, the holding member is no longer stressed by shear forces which can damage it by causing micro-breaks in its structure.
In other embodiments:
The invention also relates to an elastic holding member-timepiece component assembly for a horological movement of a timepiece comprising a holding member.
Advantageously, this assembly is made in one piece.
The invention also relates to an assemblage comprising an elastic holding member-timepiece component assembly and a support element, in particular a stub axle, said assembly being held on said support element from a first holding part of said holding member, said first holding part being configured to cooperate with a peripheral wall of said support element.
In particular, the assemblage comprises an elastic holding member-timepiece component assembly and a support element, in particular a balance shaft, said assembly being held on said support element from a second holding part of said holding member, said second holding part being configured to cooperate with a peripheral wall of said support element.
The invention also relates to a horological movement comprising at least one such assemblage.
The invention also relates to a timepiece comprising such a horological movement.
Other features and advantages will emerge clearly from the description which is given below, in an indicative and non-limiting manner, with reference to the appended drawings, wherein:
It should be noted that with regard to the balance shaft 3b, it can also be called by its synonym the balance axle and is in particular designed to receive the collet.
This elastic holding member 1 is made of a material called “fragile” material, preferably a micromachinable material. Such material may comprise silicon, quartz, corundum, silicon and silicon dioxide, DLC, metallic glass, ceramic, other at least partially amorphous material, or the like.
In this embodiment, this holding member 1 can be comprised in an elastic holding member-timepiece component assembly 120 visible in
It will be noted that in a variant of this assembly 120, only the elastic holding member 1 can be made of such a material called “fragile” material, the timepiece component 2 then being made of another material.
This assembly 120 can form part of an assemblage 130a, 130b for the horological movement 110 or else for a device 140 for performing a classification operation, by being mounted on the support element 3a, 3b, here the balance shaft or the stub axle. Such a device 140 visible in
Such a holding member 1 comprises outer and inner structures 4a, 4b as well as an upper face and a lower face 12 which are preferably flat, both of which are respectively comprised in first and second planes P1 and P2. These outer and inner structures 4a, 4b called hereinafter outer and inner peripheral walls 4a, 4b respectively delimits the outer and inner contours of this holding member 1, the inner contour defining an opening 5 of this holding member. The outer and inner peripheral walls 4a, 4b define different shapes of the holding member 1. This holding member 1 has a thickness which extends from the upper face to the lower face 12. As mentioned above, this holding member 1 may correspond to any type of collet, comprising arms 6 each including an elastic sub-arm or rigid and elastic sub-arms 7a, 7b. These arms 6 are hereinafter called “structural elements 6” of this holding member 1. Such structural elements 6 together form the body of this holding member 1. Indeed, each structural element 6 comprises a portion of the outer and inner peripheral walls 4a, 4b as well as a portion of the upper and lower faces 12. These structural elements 6 are preferably solid. In other words, these structural elements 6 are preferably not hollow. Under these conditions, the rigid sub-arms 7a and the elastic sub-arms 7b are hereinafter called respectively first structural sub-elements 7a and second structural sub-elements 7b.
The outer peripheral wall 4a of such a holding member 1 may have any shape, for example being essentially triangular, circular or even a shape similar to that of a quadrilateral. As previously mentioned, the inner peripheral wall 4b of this holding member 1 participates in defining the opening 5 of this holding member 1 into which the support element 3a, 3b is intended to be inserted. This opening 5 defines a volume in the holding member 1 which is smaller than that of a connecting part of one end of the support element 3a, 3b which is intended to be arranged therein. It will be noted that this connecting part comprises all or part of the portions 10 defined on the peripheral wall 21 of the support element 3a, 3b and which are intended in particular to cooperate with specific and/or dedicated first and second holding parts 20a, 20b of the structural elements 6. These first and second holding parts 20a, 20b are each intended to ensure mounting of said holding member 1 on different support elements 3a, 3b here a balance shaft and a stub axle. As will be seen below, these first and second holding parts 20a, 20b each comprise at least one contact area 8a, 8b configured to cooperate with the corresponding support element 3a, 3b. Each contact area 8a, 8b of the first and second holding parts 20a, 20b is able to cooperate with a corresponding contact portion 10 of the corresponding support element 3a, 3b by being preferably in a contact configuration of the plano-convex type.
As regards the outer peripheral wall 4a, it is in particular intended to be connected to the timepiece component 2 by means of at least one attachment point 11 arranged in the outer peripheral wall of the holding member 1.
For a better understanding, the invention will be described below for a holding member 1 such as a collet illustrated in
This holding member 1 therefore comprises the first structural sub-elements 7a and second structural sub-elements 7b connecting the outer and inner peripheral walls 4a, 4b to one another. It will be noted that this holding member 1 comprises as many first structural sub-elements 7a as there are second structural sub-elements 7b. The first structural sub-elements 7a are here undeformable or almost undeformable and play a role of stiffening elements of the holding member 1. As regards the second structural sub-elements 7b, they have elasticity properties in particular in comparison of the first structural sub-elements 7a. Indeed, these second sub-elements 7b are able to deform mainly in tension but also in torsion. These first structural sub-elements 7a and these second structural sub-elements 7b are defined or even distributed successively and alternately in this holding member 1. In other words, these first structural sub-elements 7a are interconnected by said second structural sub-elements 7b. More specifically, each second structural sub-element 7b is connected at its two opposite ends at connection areas 9 to two different first structural sub-elements 7a. As already mentioned previously, such first and second structural sub-elements 7a, 7b comprise in a non-limiting and non-exhaustive manner:
It will be noted that the inner faces of the second structural sub-elements 7b are essentially flat and the inner faces of the first structural sub-elements 7a may be non-flat, for example being corrugated. In this context, the inner face of each first structural sub-element 7a comprises a connecting portion 19 provided with first and second holding parts 20a, 20b visible in
These first and second holding parts 20a, 20b which can also be called “mounting parts” or “assemblage parts” or else “connecting parts”, are comprised in a connecting portion 19 of each first structural sub-element 7a, said portion 19 being included in the inner face of the holding member 1 extending over all or part of the thickness of this holding member 1. In other words, each first and second retaining part 20a, 20b therefore extends over all or part of the thickness of the holding member 1.
The first and second holding parts 20a, 20b each comprise at least one area 8a, 8b of contact with the corresponding support element 3a, 3b. Each contact area 8a, 8b can be rounded or convex or else flat. The contact area 8a, 8b of each first and second holding parts 20a, 20b, is able to cooperate with the peripheral wall 21 of a connecting part of the support element 3a, 3b in particular with a corresponding contact portion 10 defined in this peripheral wall 21, by being in a contact configuration of the plano-convex type.
These first structural sub-elements and these second structural sub-elements 7a, 7b connect the outer and inner peripheral walls 4a, 4b of the holding member 1 to each other. In this holding member 1, these first and second structural and elastic sub-elements 7a, 7b essentially allow to achieve a coupling of the elastic clamping type of the support element 3a, 3b in the opening 5 made in this holding member 1 which is defined by the inner peripheral wall 4b of this holding member 1.
As already seen, these first structural sub-elements 7a therefore comprise only the contact areas 8a, 8b of the holding member 1 with the support element 3a, 3b which can be defined in all or part of the connecting portion 19 of each first structural sub-element 7a.
In this context, the first holding part 20a comprises at least one contact area 8a. This first holding part 20a is intended to cooperate with the peripheral wall 21 of the support element 3a, for example here the stub axle 3a. Such a support element 3a has a cross section different from that of another support element 3b such as the shaft 3b, the peripheral wall of which is intended to cooperate only with the second holding part 20b of each first structural sub-element 7a of the holding member 1. The difference(s) of this cross section may relate to the shape of this section, in particular its geometric shape, but not exclusively.
It will be noted that, the shape and/or the dimensions of this section are specifically defined so that said at least one contact area 8a is the only contact area 8a of the connecting portion 19 of each first structural sub-element 7a which is configured to cooperate exclusively with the peripheral wall 21 of this support element 3a.
Indeed, in the present embodiment and with reference to
Regarding the second holding part 20b, it also comprises at least one contact area 8b. This second holding part 20b is intended to cooperate with the peripheral wall 21 of a support element 3b such as the balance shaft 3b. Such a support element 3b has a cross section different from that of another support element 3a such as the stub axle 3a, the peripheral wall of which is intended to cooperate only with the first holding part 20a of each first structural sub-element 7a of the holding member 1. The difference(s) of this cross section may relate to the shape of this section but not exclusively.
It will be noted that, the shape and/or the dimensions of this section are specifically defined so that said at least one contact area 8b is the only contact area 8b of the connecting portion 19 of each first structural sub-element 7a which is configured to cooperate exclusively with the peripheral wall 21 of this support element 3b.
Indeed, in the present embodiment, with reference to
The contact areas 8b of the first structural sub-elements 7a are provided in particular to cooperate with the contact portions 10 according to a contact configuration of the plano-convex type in which configuration where the flat surface of each contact area 8b cooperates with the corresponding contact portion 10 of convex shape of the support element 3. It should be noted here that this convex shape of each contact portion 10 is assessed relative to the flat surface of each corresponding contact area 8b opposite which this portion 10 is arranged. It will be noted that this flat surface of each contact area 8b forms a plane tangent to the diameter of the support element. In other words, the flat surface is perpendicular to the diameter and therefore to the radius R1 of the support element.
In this configuration, the presence of two flat contact areas 8b in the connecting portion 19 of each first structural sub-element 7a allows to apply a contact pressure between the holding member 1 and the support element 3b when making a mechanical connection therebetween, while consequently reducing the intensity of the stresses at these contact areas 8b and the corresponding contact portions 10 of the support element 3b when assembling and/or fixing this holding member 1 with the support element 3b, which stresses are liable to damage the holding member 1 by the appearance of breaks/fractures or else cracks.
It will be noted that these two flat contact areas 8b are preferably distributed separately over the connecting portion 19 of each first structural sub-element 7a, between the two contact areas 8a of the first holding part 20a.
In a variant, the second holding part 20b comprises a single flat contact area 8b comprised on the connecting portion 19 of each first structural sub-element 7a, equidistantly from the two contact areas 8b of the first holding part 20a.
The holding member 1 then comprises twelve contact areas 8a, 8b, six of which referenced 8a are configured to cooperate exclusively with a support element 3a, for example of the stub axle 3a type in the context of classification operations, and six others with a support element 3b, for example of the balance shaft type, to achieve precise centring of the timepiece component 2, for example a spiral, in the horological movement 110. In this holding member 1, each first structural sub-element 7a has a volume or amount of material which is substantially greater or strictly greater than the volume or amount of material constituting each second structural sub-element 7b. It will indeed be noted that the outer and inner peripheral walls 4a, 4b are separated from one another in this holding member 1 by a variable distance E which then changes depending on whether these peripheral walls 4a, 4b are comprised, for example, in a first structural sub-element 7a or else a second structural sub-element 7b. Indeed, this distance E is a maximum distance E1 when it is defined between parts of the inner and outer peripheral walls comprised in each first structural sub-element 7a, that is to say the maximum distance E1 present between the inner and outer faces of this first structural sub-element 7a. In particular, for each first structural sub-element 7a, this maximum distance E1 is defined between a part of the outer peripheral wall of this first structural sub-element 7a and each contact area 8a dedicated to cooperating with the peripheral wall 21 of the support element 3b such as the stub axle, this contact area 8a being comprised in the inner face of the inner peripheral wall of this first structural sub-element 7a. It will also be noted that this maximum distance E1 is greater than a distance E3 defined between a part of the outer peripheral wall of the first structural sub-element 7a and each contact area 8b dedicated to cooperating with the peripheral wall 21 of the support element 3b such as the balance shaft 3b, this contact area 8b being comprised in the inner face of the inner peripheral wall 4b of this first structural sub-element 7a.
Moreover, this distance E is a minimum distance E2 when it is defined between parts of the outer and inner peripheral walls 4a, 4b comprised in the second structural sub-elements 7b, or the minimum distance E2 present between the inner and outer faces of this second structural sub-element 7b. Such a minimum distance E2 is constant or substantially constant over the entire length over which these second structural sub-elements 7b extend. This length is here parallel or substantially parallel to the outer and inner peripheral walls 4a, 4b comprised in these second structural sub-elements 7b. In addition, the distance E2 is in this holding member 1, less than the smallest distance defined in the first structural sub-element 7a. In other words, the distance E2 is the smallest distance that is defined between the outer and inner peripheral walls 4a, 4b of this holding member 1.
It is therefore understood here that each second structural sub-element 7b has a cross section which is smaller than a cross section of each first structural sub-element 7a. In other words, the cross section of each second structural sub-element 7b has an area which is less than an area of the cross section of each first structural sub-element 7a. Note that the cross section of the second structural sub-element 7b is constant or substantially constant throughout the body of this second structural sub-element 7b while the cross section of the first structural sub-element 7a is inconstant/variable throughout the body of this first structural sub-element 7a. In addition, it will be noted that:
Such a configuration of the first structural sub-elements and of the second structural sub-elements 7a, 7b allows the holding member 1 to store a greater amount of elastic energy for the same clamping compared with the holding members of the prior art. Such an amount of elastic energy stored in the holding member 1 then allows to obtain a greater holding torque of the holding member on the support element 3a, 3b in the assemblage 130a, 130b of the holding member-timepiece component assembly 120 with this support element 3a, 3b. In other words, such an excess of elastic energy stored in the holding member 1 therefore increases the holding torque and allows optimum elastic clamping. In addition, it should be noted that such a configuration of the holding member 1 allows to store elastic energy ratios which are 6 to 8 times greater than those of the holding members of the prior art.
It will be noted that the arrangement of the first structural sub-elements and these second structural sub-elements 7a, 7b in the holding member 1 allows, during an insertion with clamping, a deformation of each second structural sub-element 7b allowing to accommodate the deformation of the assembly of the holding member 1 with the geometry of the connecting part of the support element 3a, 3b on which it is assembled. In addition, the mode of deformation that each second structural sub-element 7b undergoes is a toroidal torsion coupled with a radial expansion.
With reference to
When it comes to the assemblage 130a of elastic holding member-timepiece component the assembly 120 with the support element 3a such as a stub axle 3a, this step 13 comprises a fitting sub-step 14a during which the collet is placed on this stub axle 3a in anticipation, for example, of performing the classification operation. This step 13 also comprises a sub-step 16a of coupling this holding member 1 with the support element 3a here the stub axle 3a. During this sub-step 16a, the coupling is carried out without elastic clamping, thanks to the complementarity of their shape which thus allows cooperation between the latter when they are rotated when performing the classification operation. It will be noted that this complementarity of their shape results in particular from the fact that this holding member 1 and the support element 3a have different shapes. In addition, during this mounting step 13 only the contact areas referenced 8a cooperate with the portions 10 of the peripheral wall 21 of the connecting part of the support element 3a.
When it comes to the assemblage 130b of the elastic holding member-timepiece component assembly 120 with the support element 3b such as a balance shaft 3b, this step 13 comprises a sub-step of elastic deformation 14b of the holding member 1 in particular of a central area of this holding member 1, the contour of which comprises said opening 5, which deformation resulting from the application of a contact force on the contact areas 8b of the first structural sub-elements 7a by the portions 10 of the peripheral wall 21 of the connecting part of the support element 3b.
As previously mentioned, this elastic deformation of the holding member 1 results from the application of the contact force on the contact areas 8b of the first structural sub-elements 7a by the portions 10 of the peripheral wall 21 of the support element 3b. Such a deformation sub-step 14b comprises a phase of displacement 15 of the first structural sub-elements 7a under the action of the contact force applied thereto. Such a displacement of the first structural sub-elements 7a is carried out in a direction comprised between a radial direction B1 relative to a central axis C which is common to the support element 3b and to the holding member 1, and a direction B2 combined with this central axis C. It will be noted that this direction B2 is perpendicular to the direction B1 and is oriented in a defined direction from the lower face 12 towards the upper face. The contact force is preferably perpendicular or substantially perpendicular to each contact area 8b.
It will be noted that in the context of the embodiment of the holding member 1 described and illustrated in
A first deformation otherwise called “torsional elastic deformation” of these second structural sub-elements 7b. During this torsional deformation, each second structural sub-element 7b is driven at its two ends in the same direction of rotation B4 by the first displacing structural sub-elements 7a to which such ends are connected. It will be noted that only part of the body of these second structural sub-elements 7b is torsionally deformable here the ends of these second structural sub-elements 7b. Such a first deformation contributes in particular to then causing a torsional deformation of each structural element 6. This first deformation allows to improve the insertion of the support element 3b into the opening 5 of the holding member 1 while helping to prevent any breakage of the holding member 1 and/or any appearance of a crack in this member 1 during its assemblage with the support element 3b.
A second deformation otherwise called “tension deformation” or else “elastic extension deformation” of the second structural sub-elements 7b. During this extension deformation, each second structural sub-element 7b is pulled at its two ends in the longitudinal direction B3 in opposite directions by the first displacing structural sub-elements 7a to which such ends are connected. Such a second deformation of the second structural sub-element 7b contributes in particular to the fact that each structural element 6 stores a large amount of elastic energy. In other words, the support element 1 also stores a large amount of elastic energy
This double elastic deformation of the second structural sub-elements 7b can be carried out simultaneously or substantially simultaneously, or alternatively successively or substantially successively. It will be noted in the context of the implementation of this phase 15, when this double elastic deformation is carried out successively or substantially successively, the first deformation is then carried out before the second deformation.
This mounting step 13 then comprises a sub-step 16b of fixing the holding member 1 on the support element 3b. Such a fixing sub-step 16b comprises a phase 17 of performing a radial elastic clamping of the holding member 1 on the support element 3b. It is therefore understood that in such a state of stress, the holding member 1 stores a large amount of elastic energy which contributes to giving it a substantial holding torque, in particular allowing optimum twisting by elastic clamping.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19167903.4 | Apr 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/059815 | 4/6/2020 | WO | 00 |
