HK1223425B - Balance spring stud-holder - Google Patents

Description

Balance spring stud retainer

Technical Field

The invention relates to an assembly for holding or supporting a timepiece balance spring, comprising a balance spring stud and a stud holder, wherein the stud holder comprises:

-a base comprising a first stop member extending along a longitudinal axis of the base;

-means to fasten said stud-holder to the escapement.

Background

In mechanical watches, a regulating member comprising a sprung balance device is often used. Typically, the inner end of the balance spring is attached to a collet provided on the balance staff. In order to attach and position the outer end of the balance spring, it is known to use a stud holder containing the balance spring stud, which is combined with a clamping screw to clamp the stud against the portion of the balance spring engaged in the stud holder.

In such an assembly, the outer pile holder is typically attached to a pendulum plate, which is also used to attach one end of the pendulum shaft. In practice, during assembly and/or set-up time, it is difficult to perform operations using these various elements, since the access is limited and the components have very small dimensions. In addition, with this arrangement it is common for the balance spring clamping screw or balance spring stud retainer to become loose and/or lost in operations such as adjusting the effective length of the balance spring.

Disclosure of Invention

One purpose of the present invention is to overcome the drawbacks of the prior art by proposing an assembly for holding or supporting a timepiece balance spring, which allows simplified assembly or disassembly of the balance spring stud.

To this end, the invention relates to an assembly for holding or supporting a timepiece balance spring, comprising a balance spring stud and a stud holder, wherein the stud holder comprises:

-a base comprising a first stop member extending along its longitudinal axis;

and means for fastening the outer pile holder to the balance bridge,

characterised in that the external pile holder further comprises elastic means provided with a second stop member, said elastic means extending along the longitudinal axis of the base so that the second stop member is in a position facing the first stop member, the space between the first stop member and the second stop member forming a housing for the external pile, the elastic means naturally exerting a stress on the external pile when placed in the housing, the housing being expandable by deformation of the elastic means to release the external pile.

One advantage of the present invention is that it allows for simple assembly/disassembly of the outer pile.

In a first advantageous embodiment, the elastic means comprise at least one arm, the free end of which carries the second stop member.

In a second advantageous embodiment, the elastic means comprise two arms extending from said base, which are integral with each other and have a convex shape.

In a third advantageous embodiment, the two arms forming the elastic means are symmetrical with respect to the longitudinal axis of the base.

In a fourth advantageous embodiment, both arms comprise one notch.

In another advantageous embodiment, the external pile holder is made of a plastic material.

In another advantageous embodiment, the external pile holder is made of a metallic material.

In another advantageous embodiment, the outer pile holder is made of a single crystal material.

In another advantageous embodiment, the attachment means comprise a hole arranged in the balance bridge, said hole cooperating with the first hole of the outer pile holder, and a screw being inserted in both holes.

In another advantageous embodiment, the attachment means further comprise a projection arranged on the pendulum plate and a second hole arranged in the outer pile holder, said projection cooperating with said second hole.

In another advantageous embodiment, the attachment means further comprise a projection arranged on the outer pile holder and a second hole arranged in the pendulum plate, said projection cooperating with said second hole.

In a further advantageous embodiment, the attachment means further comprise a recess arranged on the pendulum plate and a projection arranged on the outer pile holder, said recess cooperating with said projection.

In another advantageous embodiment said first hole has a circular arc shape, allowing the outer pile holder to pivot angularly.

In another advantageous embodiment, the outer pile holder and the balance bridge are one piece.

Drawings

Objects, advantages and features of the invention will appear more clearly from the following detailed description of at least one embodiment of the invention, given by way of non-limiting example only and illustrated in the accompanying drawings, in which:

figures 1a-1d show schematic views of a first embodiment of a holding assembly according to the invention.

Figures 2a-2d show schematic views of a second embodiment of the retaining assembly according to the invention.

Figures 3a-3b show schematic views of a first alternative of the attachment device according to the invention.

Figures 4a-4c show schematic views of a second alternative of the attachment device according to the invention.

Figure 5 shows a schematic view of a variant of a second alternative of the attachment device according to the invention.

Figure 6 shows a schematic view of a third alternative of the attachment device according to the invention.

Figure 7 shows a schematic view of a fourth alternative of the attachment device according to the invention.

Figure 8 shows a schematic view of a variant of the invention.

Detailed Description

The invention proceeds from the following general idea: an assembly for holding or supporting a timepiece balance spring is provided that allows the balance spring stud to be more easily assembled/disassembled.

Figures 1a-1d show a schematic view of an assembly 1 for holding or supporting a balance spring stud according to a first embodiment. The holding assembly 1 comprises an outer pile holder 3, the outer pile holder 3 being arranged to be attached to a pendulum plate 5 by means of attachment means 7. The holding assembly also comprises a balance spring stud 9 attached to one coil of the balance spring.

The outer pile holder 3 comprises a base 30 having a longitudinal axis. The base 30 may have any shape. Extending from the base 30 is a first stop member 32. The first stop member takes the form of a protruding portion of the base 30.

Advantageously according to the invention, the outer pile holder 3 further comprises resilient means 34 for providing attachment of the outer pile 9 to the outer pile holder.

In a first embodiment, seen in fig. 1a, the elastic means comprise an arm 35. The arm 35 extends from the base 30 in a similar direction as the first stop member 32, i.e. in a similar direction as the longitudinal axis. The arm 35 has a rectilinear shape terminating in a curved portion and comprises a free end on which a second stop member 36 is arranged. The elastic arm 35 and the second stopper member 36 are formed such that: in the initial position, the second stop member 36 is in a position facing the first stop member 32 when the resilient arm 35 is in the rest mode, i.e. when no stress is applied to said resilient arm.

In this case, there is a space 4 between the first stop member 32 and the second stop member 36, which space forms a receptacle for the outer pile 9.

According to the invention, the elastic arms 35 are cleverly designed: when the outer pile 9 is placed in the receptacle 4 present between the first stop member 32 and the second stop member 36, said resilient arms 35 naturally exert a force on the outer pile 9, as seen in fig. 1 c.

Therefore, in order to assemble or disassemble the outer pile 9 on the outer pile holder 3, stress C must be applied to the arms 35. This stress C is applied to the elastic arms 35 to elastically deform said arms.

As seen in fig. 1b, this elastic deformation causes a displacement of the second stop member 36 relative to the first stop member 32. This displacement is intended to enlarge the accommodation. This enlargement of the receiving portion 4 allows the outer pile 9 to be placed therein or released therefrom. In case of dismantling of the outer pile 9, the displacement of the second stop member 36 relative to the first stop member 32 is intended to reduce the stress exerted on the outer pile 9.

This embodiment has the advantage of simplicity, since there are no screws or complicated operations. The spring arm only needs to be moved aside to release the outer peg 9 or to insert the outer peg 9 in the receptacle. In addition, the system allows the assembly or disassembly of the outer piles without shock.

In a variant of this first embodiment, the elastic arm 35 has a non-rectilinear shape. For example, the arms may be curved with a convex or concave profile, as seen in fig. 1 d.

In a second embodiment, seen in fig. 2a, the resilient means 340 comprises two resilient arms 350. Each resilient arm 350 includes a first end and a second end. The arms 350 extend from the base 300 via the first end in a similar direction as the first stop member 320 (i.e., in a similar direction as the longitudinal axis).

In this second embodiment, the two resilient arms 350 are connected at their second ends. At this connection point 351, the second stopper member 360 is arranged to face the first stopper member 320.

According to the invention, both said elastic arms 350 have ingeniously curved portions. The curved portion is preferably convex. This convex shape of the resilient arms 350 allows for simple assembly/disassembly of the outer pile 9. In fact, to assemble/disassemble the outer pile, a stress C' is applied to both elastic arms 350 simultaneously. The stress C' applied to each resilient arm 350 causes deformation of the arm 350. This deformation is intended to bring them closer together, as seen in fig. 2 b.

It can thus be observed that the deformation of the arm 350 causes a displacement of the second stop member 360. This displacement of the second stop member is characterized in that the second stop member 360 is moved away from the first stop member 320, thereby enlarging the receptacle 4 between the first stop member 320 and the second stop member 360.

The enlargement of the accommodation thus allows the outer pile 9 to be easily placed therein or removed therefrom.

When the operator wishes to assemble the outer pile, he exerts a stress C' on the two elastic arms 350. This stress or pressure C' may be applied using a tool, such as a clamp. The stress C' applied by the operator is intended to deform the arm 350, so that the second stop member 360 is displaced and enlarges the housing.

The operator then takes the outer pile 9 and places it adjacent the first stop member 320. The first stop member may be provided with a recess for immobilizing the outer pile 9. When the outer pile 9 is fixed to the first stop member 320, the operator releases the pressure C' exerted on the resilient arm 350, causing the displacement of the second stop member 360. This displacement is intended to move the second stop member 360 closer to the first stop member 320 until the second stop member 360 comes into contact with the outer pile 9, as seen in fig. 2C. The outer pile 9 is dimensioned larger than the receiving portion 4. Therefore, when the second stop member 360 is moved back to the initial position, i.e., the position where the elastic arm 350 does not work, the second stop member 360 cannot return to the exact initial position due to the large size of the outer pile 9.

The second stop member 360 thus exerts a force on said outer pile 9 to hold it between the first stop member 320 and the second stop member 360.

When the operator wishes to dismantle the outer pile 9, he exerts a stress, such as a pressure force C', on the resilient arms 350. This pressure results in a deformation of the resilient arms 350 and thus a displacement of the second stop member 360. This displacement increases the accommodation 4 and thus releases the outer pile 9 so that the operator can hold it.

In a variation of the second embodiment seen in 2d, each resilient arm comprises a recess 352 on its outer surface. These notches 352 serve as specific areas so that a tool for applying pressure on the resilient arms 352 can be placed thereon and not slip during assembly or disassembly.

For fastening the outer pile holder to the pendulum plate, attachment means 7 are provided.

In a first alternative seen in fig. 3a and 3b, the attachment means 7 comprises a hole 70, which may or may not be a through hole, the hole 70 being arranged on the balance bridge and being associated with a through hole 71 arranged on the outer pile holder. These two holes allow fastening the outer pile holder to the pendulum plate using screws 72. The single screw 72 for attaching the outer pile holder 3 to the balance bridge 5 may serve as a rotation axis. In fact, it is conceivable to allow angular adjustment of the outer pile holder by the operator turning the outer pile holder around the axis of the screw using this single attachment point.

In a second alternative seen in fig. 4a, the attachment means 7 comprise a hole 70, which may or may not be a through hole, arranged in the pendulum plate 5, and a first through hole 71 arranged in the outer pile holder 3. These two holes allow fastening the outer pile holder 3 to the balance bridge 5 using screws 72. The attachment means 7 further comprises a protrusion 74 and a second hole 75, said second hole 75 may or may not be a through hole. The projection 74 may be arranged on the outer pile holder 3 and the second hole 75 may be arranged in the pendulum plate, as seen in fig. 4a, or conversely as seen in fig. 4b and 4 c.

The pair of structures comprising the projection 74-the second hole 75 serves to stabilize the position of the external pile holder 3 with respect to the pendulum plate 5. In fact, the presence of the projection 74 inserted into the second hole 75 makes it possible to hinder the angular movement when the operator tightens the screw 72. In fact, if there is no projection 74, there is a risk of angular displacement of the outer pile holder 3 when the screw 72 is tightened to fasten the outer pile holder 3 to the pendulum plate 5.

In a variant of the second alternative seen in fig. 5, the first hole 71 arranged in the outer pile holder 3 takes the form of an elongated hole or slot, into which first hole 71 a screw 72 is inserted. The slot forms an arc to allow adjustment of the angular position of the outer pile holder 3. In this case, the projections 74 are used as pivot shafts, enabling the outer pile holder 3 to be pivoted to adjust its position once the screws are loosened.

In a third alternative seen in fig. 6, the attachment means 7 comprise a hole 70, which may or may not be a through hole, arranged in the pendulum plate 5, and a first through hole 71 arranged in the outer pile holder 3. These two holes allow fastening the outer pile holder to the pendulum plate using screws 72. The attachment means 7 further comprise guiding means for stabilizing the position of the outer pile holder and as a pivot axis for angular adjustment of said outer pile holder. To achieve this, the guiding means comprise a recess 76 arranged in the outer pile holder and a projection or protrusion 77 arranged on the balance bridge. The recess 76 and the projection 77 can cooperate with each other, the projection 77 being able to pass through the recess 76. The recess 76 has a circular arc shape. When the outer pile holder 3 is mounted on the balance bridge 5, the protrusions 77 are inserted into the recesses 76 to limit the movement of said outer pile holder 3 relative to the balance bridge 5.

The projection 77 may be dimensioned not to allow freedom of movement of the outer pile holder 3, or conversely it may be dimensioned to allow angular adjustment of the position of the outer pile holder. In the example where the protrusion 77 and the recess 76 have a circular arc shape, if the recess has a larger angle than the protrusion, the outer pile holder may be adjusted if the hole 70 is also circular arc shaped.

In a fourth alternative, the attachment means 7 comprise guiding means for the third alternative, namely a recess 76 arranged on the outer pile holder and a projection 77 arranged on the pendulum plate. The attachment means 7 further comprise a brake 78. The brake 78 seen in fig. 7 comprises flexible arms. The flexible arm extends from the base in a direction opposite the first stop member. The flexible arm acts on the pendulum plate so that it limits the rotation of the outer pile holder 3 by friction.

It will of course be understood that the stud holder 3 may be provided on the upper surface of the balance bridge 5, but may also be on the lower surface, i.e. the surface facing the balance spring. This arrangement on the lower surface allows the outer pile 9 to be moved closer to the pendulum shaft. This makes it possible to use a smaller diameter balance spring.

For manufacturing the outer pile holder 3, according to a first solution, a plurality of materials may be used, and the outer pile holder 3 may be made of a plastic material, such as polyurethane. The advantage of this material is that it can be easily shaped using moulding techniques and thus ensures good reproducibility. In addition, the material has good mechanical properties, which are easily deformable but still have good wear resistance.

According to the second aspect, a metal material may be used. The metal material is of two types: crystalline materials and amorphous materials.

The crystalline material may be a pure metal, such as iron or aluminium, or an alloy, such as brass or steel. These metallic materials have the first advantage of exhibiting good mechanical properties. In fact, metals have a high elastic limit to allow them to withstand high stresses before plastic deformation. For example, aluminum has an elastic limit of 180 to 240GPa, steel has an elastic limit of 235 to 1500GPa, depending on the type of steel, while plywood (glulam) has an elastic limit of 32 GPa.

In addition, these metal materials have an advantage of being easily formed. In fact, it can be shaped by casting or injection molding or by stamping (i.e. by press cutting).

Alternatively, LIGA techniques may be used, which include X-ray lithography followed by electroplating by electrolytic deposition, and finally a shaping step. The LIGA technique has the advantage of low cost and can be implemented quickly while ensuring good reproducibility and high precision production.

Amorphous metals, also referred to as metallic glasses, are materials having a disordered atomic-scale structure (amorphous structure). In fact, in the case of an amorphous material, by increasing the elastic limit σ E, the ratio of the elastic limit to the young's modulus σ E/E increases. The stress beyond which the material no longer returns to its original shape is thus also increased. This improvement in σ E/E ratio thus allows greater deformation. This makes it possible to optimize the dimensions of the outer pile holder and the resilient arms, depending on whether it is desired to change the pressure exerted by the second stop member on the outer pile holder.

Another advantage of these amorphous materials is that they offer new forming possibilities for forming parts into complex shapes with greater precision. In fact, amorphous metals have specific softening properties while remaining amorphous within a given temperature range [ Tg-Tx ] specific to each alloy (where Tx is the crystallization temperature and Tg is the glass transition temperature). These metals can be formed at relatively low stress and low temperature. This means that the fine geometry can be reproduced very accurately, since the viscosity of the alloy is greatly reduced and thus all the details of the die are absorbed.

Another approach involves the use of single crystal materials such as silicon. The material has friction resistance, high elastic limit and low density. This material is also attractive due to its diamagnetic properties and high corrosion resistance. Since the system according to the invention allows the outer piles 9 to be assembled/disassembled without impact, materials such as silicon may be used.

For the production of such components from silicon, the known LIGA method or DRIE method (deep back ion etching method) is used, which provides good reproducibility and high precision components.

In the third embodiment, the outer pile holder 3 and the balance bridge 5 are made in one piece, i.e. they form one and the same single component. In this respect, the pendulum plate 5 acts as a base 3, said base 3 comprising a first stop member from which extend one or more resilient arms 35,350 forming resilient means 34, 340.

This third embodiment eliminates the need for means 7 for attaching the external pile holder 3 to the pendulum plate 5. The risk of improper positioning during assembly of the external pile holder to the balance bridge is thus eliminated.

In addition, this third embodiment reduces cost because there is only one component instead of two, and the method has one step less.

It is clear that various variations and/or modifications and/or combinations obvious to a person skilled in the art may be made to the various embodiments described above without departing from the scope of the invention as defined in the appended claims.

For example, the first stop member may be configured to act as a stop member for the resilient arm. In fact, depending on the dimensions and the material forming the arms, there is a risk of breakage or elastic deformation. To solve this problem, the first stopper member 320a seen in fig. 8 is designed to extend in width so as to have a larger width than the base 300. This feature allows for limited displacement of the arm 350 when the stress C' is applied. Thus, deformation of the arms 350 is limited and the risk of breakage is reduced.

The outer pile, the first stop member and/or the second stop member may also be provided with a flat portion to prevent the outer pile from rotating around itself.

Claims (14)

1. A holding assembly for holding or supporting a timepiece balance spring, the holding assembly comprising a balance spring stud (9) and a stud holder (3), wherein the stud holder comprises:

-a base (30,300) comprising a first stop member (32, 320) extending along a longitudinal axis (L) of the base;

-attaching means (7) for attaching the outer pile holder to a pendulum plate (5),

characterized in that the outer pile holder further comprises a resilient means (34,340) provided with a second stop member (36, 360), the resilient means extending along the longitudinal axis of the base part such that the second stop member is in a position facing the first stop member, the space between the first and second stop members forming a receptacle (4) for the outer pile; said elastic means naturally exert a stress on the external pile when it is placed in the housing, said housing being able to expand to release the external pile by deformation of said elastic means, said elastic means (340) comprising two arms (350) extending from said base, said two arms being engaged with each other and having a convex shape, so that the application of a stress to said two arms bringing them closer causes the displacement of a second stop member (360) to expand said housing.

2. The holding assembly according to claim 1, wherein the two arms forming the elastic means are symmetrical with respect to the longitudinal axis of the base.

3. The retention assembly of claim 1, wherein the two arms each include a notch (352).

4. Holding assembly according to claim 1, wherein the external pile holder (3) is made of a plastic material.

5. Holding assembly according to claim 1, wherein the outer pile holder (3) is made of a metallic material.

6. Holding assembly according to claim 1, wherein the outer pile holder (3) is made of a single crystal material.

7. Holding assembly according to claim 1, wherein the attachment means (7) comprises a hole (70) arranged in the pendulum plate, which hole cooperates with a first hole (71) of the outer pile holder, a screw (72) being inserted in the hole (70) and the first hole (71).

8. The holding assembly according to claim 7, wherein the attachment means (7) further comprises a projection (74) arranged on the pendulum plate and a second hole (75) arranged in the external pile holder, the projection cooperating with the second hole.

9. The holding assembly according to claim 7, wherein the attachment means (7) further comprises a projection (74) arranged on the outer pile holder and a second hole (75) arranged in the pendulum plate, the projection cooperating with the second hole.

10. The holding assembly according to claim 7, wherein the attachment means (7) further comprises a protrusion (77) arranged on the pendulum plate and a recess (76) arranged in the external pile holder, the recess cooperating with the protrusion.

11. The holding assembly according to claim 10, wherein the protrusion (77) and the recess (76) have the same dimensions.

12. Holding assembly according to claim 10, wherein the first hole (71) has the shape of a circular arc, the recess (76) extending at a larger angle than the protrusion (77) to allow angular pivoting of the outer pile holder.

13. Holding assembly according to claim 10, wherein the first hole (71) has the shape of a circular arc, the recess (76) extending at a larger angle than the protrusion (77) to allow angular pivoting of the outer pile holder.

14. The retention assembly of claim 1, wherein the outer pile retainer and the balance bar are a unitary piece.