CH714771A2 - Mechanical energy storage device, in particular for a timepiece, a watch movement and a timepiece including such a device. - Google Patents

Abstract

The invention relates to a mechanical energy storage device comprising an elastic structure (8a) and a pulley (15) on which is fixed a flexible link (15a) adapted to wind on the pulley, the flexible link s extending from the pulley to a free end secured to an anchoring portion (13) belonging to the elastic structure, the anchoring portion being at a maximum distance from the pulley when the elastic structure is in the rest position and the elastic structure being shaped so that the anchoring portion is movable in a translation direction (14) passing through the pulley. Such a device can act as a source of energy in a mechanical timepiece.

Description

CH 714 771 A2

Description

TECHNICAL FIELD The present description relates to mechanical energy storage devices in particular for timepieces, as well as to watch movements and to timepieces comprising such devices.

TECHNOLOGICAL BACKGROUND Mechanical energy storage devices are known comprising at least a first elastic structure and a control member that can be actuated to elastically deform the first elastic structure from a rest position in order to accumulate therein. mechanical energy.

In known mechanical energy storage devices, in particular in the watchmaking field, the elastic member may for example be a barrel spring.

The present description aims in particular to improve the mechanical storage devices of the prior art.

OBJECTS AND SUMMARY OF THE DESCRIPTION For this purpose, a mechanical energy storage device of the type in question is characterized in that the control member is a pulley rotatably mounted around an axis of rotation and on which is fixed a first flexible link adapted to wind on the pulley when said pulley is rotated in a first direction and to unwind from the pulley when said pulley rotates in a second direction opposite to the first direction, the first flexible link s extending from the pulley to a free end integral with an anchoring part belonging to the first elastic structure, said anchoring part of the first elastic structure being at a maximum distance from the pulley when said first elastic structure is rest position and the first elastic structure being shaped so that the anchoring part of the first elastic structure is movable in tr anslation in a direction of travel passing through the pulley.

Thanks to these provisions, the pulley can elastically deform the first elastic structure by accumulating mechanical energy therein when said pulley is driven in the first direction of rotation, and the first elastic structure can restore its mechanical energy by pulling on the first flexible link by unwinding from the pulley, which rotates the pulley in the second direction when said pulley is not driven in the first direction.

In particular, the following advantages can be obtained:

- unlike conventional barrel springs, the torque applied by the first elastic structure to the pulley can optionally be controlled by the design of the elastic structure and the shape of the pulley, possibly for this torque being substantially constant, possibly for this couple either Student;

- We can control the number of pulley turns represented by the maximum tension of the first elastic structure; for example, by using a very small diameter pulley, a large number of turns can be obtained;

- the energy storage device can be used directly in place of a barrel spring, without having to review the entire design of the timepiece;

- the energy storage device dissipates very little energy by friction, unlike a barrel spring.

In various embodiments of the mechanical energy storage device, one can optionally have recourse to one and / or the other of the following provisions:

- The first elastic structure comprises two rigid supports and two elastic arms arranged in a V shape open towards the pulley, the elastic arms extending diverging from said anchoring part of the first elastic structure to connected external ends respectively to said rigid supports of the first elastic structure;

said anchoring part of the first elastic structure is rigid, each elastic arm of the first elastic structure comprises a rigid intermediate part and first and second elastic branches, said rigid intermediate part being connected respectively to said anchoring part of the first elastic structure and to one of said rigid supports of the first elastic structure respectively by said first and second elastic branches;

- the first and second elastic branches are curved with a concavity turned away from the pulley;

- The anchoring part of the first elastic structure has bearing edges facing the first elastic branches of the first elastic structure, said bearing edges of the anchoring part being generally oriented towards the pulley and being arranged at beyond the first elastic branches of the first elastic structure with respect to the pulley;

each rigid intermediate part of the first elastic structure has a convex edge opposite the first corresponding elastic branch, the convex edge of said intermediate part being adapted to come into rolling bearing against the corresponding first elastic branch of the first elastic structure when the anchoring part is sufficiently displaced towards the pulley from the rest position, by applying the first elastic branch against the bearing edge of the anchoring part;

CH 714 771 A2

- The supports of the first elastic structure have support edges oriented towards the second elastic branches of the first elastic structure and opposite the pulley and towards the second elastic branches of the first elastic structure;

each rigid intermediate part of the first elastic structure has an external convex edge opposite the corresponding second elastic branch, the external convex edge of said intermediate part being adapted to come into rolling contact against the corresponding second elastic branch of the first elastic structure when the anchoring part is sufficiently displaced towards the pulley from the rest position, by applying said second elastic branch against the bearing edge of the corresponding support;

- The supports of the first elastic structure are resiliently movable relative to each other substantially perpendicular to the direction of movement;

- the first elastic structure extends in a plane perpendicular to the axis of rotation of the pulley;

- the first elastic structure is monolithic;

- The mechanical energy storage device further comprises a second elastic structure which is symmetrical with said first elastic structure with respect to the axis of rotation of the pulley, the mechanical energy storage device further comprising a second link flexible adapted to wind on the pulley when said pulley is rotated in the first direction and to unwind from the pulley when said pulley rotates in the second direction, the second flexible link extending from the pulley to a free end secured to an anchoring part belonging to the second elastic structure, said anchoring part of the second elastic structure being at a maximum distance from the pulley when said second elastic structure is in the rest position and the second elastic structure being shaped so that the anchoring part of the second elastic structure is movable in tr anslation in said direction of travel;

- the first and second flexible links are formed in one piece.

Furthermore, the invention also relates to a timepiece movement comprising the mechanical energy storage device as defined above.

Finally, the invention also relates to a timepiece comprising a timepiece movement as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages will appear during the following description, two embodiments, given by way of nonlimiting examples, with reference to the accompanying drawings.

In the drawings:

fig. 1 is a schematic view of a timepiece which may include a mechanical energy collection mechanism, FIG. 2 is a block diagram of the movement of the timepiece of FIG. 1, fig. 3 is a plan view of a first embodiment of the mechanical energy collection mechanism of the movement of FIG. 2, in the rest position, and FIG. 4 is a plan view of a second embodiment of the mechanical energy collection mechanism of the movement of FIG. 2, in the rest position.

MORE DETAILED DESCRIPTION In the various figures, the same references designate identical or similar elements.

[0014] FIG. 1 represents a timepiece 1 such as a watch, comprising:

- a housing 2,

- a watch movement 3 contained in the case 2,

-generally, a winder4,

- a dial 5,

- a glass 6 covering the dial 5,

a time indicator 7, comprising for example two hands 7a, 7b respectively for the hours and the minutes, placed between the glass 6 and the dial 5 and actuated by the watch movement 3.

As shown schematically in FIG. 2, the watch movement 3 can for example include:

- a device 14 for collecting mechanical energy,

a device 8 for storing mechanical energy, for example a barrel spring, supplied with mechanical energy by the winder 4 and / or a device for collecting mechanical energy (not shown) adapted to collect the energy of the movements of the person wearing the timepiece 1,

a mechanical transmission 9 driven by the device 8 for storing mechanical energy,

CH 714 771 A2

- the above-mentioned time indicator 7,

- an energy distribution member 10 (for example an escape wheel),

an anchor 11 adapted to sequentially retain and release the energy distribution member 10,

- A regulator 12, which is a mechanism comprising an oscillating inertial regulating member, controlling the anchor 11 to move it regularly so that the energy distribution member is moved step by step at constant time intervals.

The anchor 11 and the regulator 12 form a mechanism 13 which may possibly be a monolithic system formed in the same plate.

As shown in FIG. 3, the mechanical energy storage device 8 may comprise at least a first elastic structure 8a and a control member, in this case pulley 15 which can be actuated to elastically deform the first elastic structure 8a from a rest position so to accumulate mechanical energy. It will be noted that in the present description, the designation first or first does not imply that the device comprises any other element similar or identical to that called first or first.

The pulley 15 rotatably mounted about a rotation axis 16, on an integral part of the housing 2. It can be controlled by the winder 4 and / or by the aforementioned mechanical energy collection device.

The first elastic structure 8a can be a planar structure, extending along a plane perpendicular to the axis of rotation 16. The pulley 15 can extend in the same plane as the first elastic structure 8a.

The first elastic structure 8a can be monolithic, formed in the same plate (not referenced) whose moving parts are designed to move essentially in the plane of the plate.

The plate in question may be thin, for example about 0.05 to about 1 mm, depending on the nature of the material of the plate.

The plate may have transverse dimensions, in the plane of the plate (in particular width and length, or diameter), of between approximately 10 mm and 40 mm.

The plate can be made of any suitable rigid material. Examples of materials that can be used to make the plate include silicon, nickel, iron / nickel alloy, steel, titanium. In the case of silicon, the thickness of the plate 14a can for example be between 0.2 and 0.6 mm.

As understood here, the term “monolithic structure” is understood to mean a structure composed of elements which, by the nature or the form of their assembly, are integral with one another to the point that any deformation of a component leads to a distortion of other parts. The monolithic structure can advantageously be formed in a single piece of material, possibly treated to present an outer layer of a different nature from the rest of the material (for example an oxidized layer). As a variant, the monolithic structure may also include certain added parts (for example glued, welded or other) in the plane of the plate.

The various bodies formed in the plate, for example are obtained by making openings in the plate, obtained by any manufacturing process used in micromechanics, in particular the processes used for the manufacture of MEMS.

In the case of a silicon wafer, the wafer can be locally hollowed out, for example by deep reactive ion etching (DRIE - "Deep Reactive Ion Etching") or possibly by laser cutting for small series.

In the case of an iron / nickel plate, the plate could in particular be produced by the LIGA process, or by laser cutting.

In the case of a steel or titanium plate, the plate can be hollowed out, for example by wire EDM (WEDM).

The constituent parts of the mechanical energy storage mechanism 8 will now be described in more detail. Some of these parts are rigid and others (notably those called elastic branches or beams) are elastically deformable, essentially in bending. The difference between the rigid parts and the elastic parts is their stiffness in the plane of the plate, which is due to their shape and in particular to their slenderness. The slenderness can be measured in particular by the slenderness ratio (length / width ratio of the part concerned). For example, the rigid parts have a stiffness at least about 100 times higher in the plane of the plate, than the elastic parts. Typical dimensions for elastic connections, for example the elastic branches which will be described below, include lengths for example between 5 and 13 mm and widths for example between 0.01 mm (10 μm) and 0.04 mm (40 μm), in particular approximately 0.025 mm (25 μm). Given the widths of the elastic branches and the thickness of the plate, the slenderness ratio of these elastic tongues in longitudinal section (thickness / width) is between 5 and 60. The slenderness ratio in section (thickness / width) as large as possible is to be preferred to limit deformations out of plane.

On the pulley 15 is fixed a first flexible link 15a adapted to wind around the periphery of the pulley 15 when said pulley 15 is rotated in a first direction RI and to unwind from the pulley 15 when said pulley 15 rotates in a second direction R2 opposite to the first direction RL The first flexible link 15a can be a wire or a ribbon

CH 714 771 A2 made of any flexible and not very extensible material, for example Kevlar® or other. Alternatively, the first flexible link 15a could be a metal chain or the like. The first flexible link 15a can be fixed to the pulley 15 and to the anchoring part 13 by any known means, mechanical fixing, bonding or welding, or other.

The first flexible link 15a extends from the pulley 15 to a free end secured to an anchoring part 13 belonging to the first elastic structure 8a.

Said anchoring part 13 of the first elastic structure 8a is distant from the pulley 15 at most when said first elastic structure 8a is in the rest position and is closer to the pulley 15 when the first elastic structure is deformed at maximum, having stored the maximum mechanical potential energy.

The first elastic structure 8a is shaped so that the anchoring part 13 is movable in translation in a direction of movement 14 passing through the pulley 15 (possibly passing through the axis of rotation 16 of the pulley 15).

In the first embodiment shown in FIG. 3, the first elastic structure 8a comprises two rigid supports 20 and two elastic arms 17-19 arranged in a V shape open towards the pulley 15, the elastic arms 17-19 extending diverging from said anchoring part 13 up to 'at external ends connected respectively to said rigid supports 20.

The rigid supports 20 may be secured respectively to frame parts 21 mounted directly or indirectly on the housing 2 above. The rigid supports 20 and / or frame parts 21 can be either integral with the housing 2, or movable relative to the housing 2. In the latter case, the rigid supports 20 and / or frame parts 21 can optionally be connected together by elastic parts (not shown) allowing relative movement between the rigid supports 20 and / or frame parts 21 substantially perpendicular to the direction of movement 14.

Said anchoring part 13 can be rigid.

Each elastic arm 17-19 may comprise a rigid intermediate part 17 and first and second elastic branches 18, 19, said rigid intermediate part 17 being connected respectively to said anchoring part 13 and to one of said rigid supports 20 respectively by said first and second elastic branches 18, 19.

The first and second elastic branches 18, 19 can be curved with a concavity turned away from the pulley 15.

The anchoring portion 13 may include bearing edges 13a facing the first elastic branches 18, said bearing edges 13a being disposed beyond the first elastic branches 18 relative to the pulley 15. Said edges d the support 13a can be convex and have a convexity oriented towards the pulley 15.

Each rigid intermediate part 17 may include a first convex edge 17a opposite the first corresponding elastic branch 18, the first convex edge 17a of said intermediate part 17 and the corresponding bearing edge 13a of the anchoring part 13 being adapted to come into abutment on either side of the corresponding first elastic branch 18 of the first elastic structure 8a (advantageously in the vicinity of the same point of the first elastic branch 18) when the anchoring part 13 is sufficiently moved to pulley 15 from the rest position.

The supports 20 may have support edges 20a oriented towards the second elastic branches 19 and opposite to the pulley 15. Said support edges 20a may have a concavity oriented opposite the pulley 15 and towards the second elastic branches 19.

Each rigid intermediate portion 17 may include a second convex external edge 17b opposite the corresponding second elastic branch 19, the second convex edge 17b of said intermediate portion 17 being adapted to come into rolling contact against the corresponding second elastic branch 19 when the anchoring part 13 is sufficiently displaced towards the pulley 15 from the rest position, by applying the second elastic branch 19 against the bearing edge 20a of the corresponding support 20.

These provisions contribute to the fact that the first elastic structure 8a can store a particularly large mechanical energy, by applying to the pulley 15 a substantially constant torque when the convex edges 17a, 17b are in rolling support respectively against the first and second elastic branches 18, 19 themselves applied respectively against the bearing edges 20a, 20b, since the force applied by the deformations of the first and second elastic branches 18, 19 essentially depends on their initial deflection before rolling the convex edges 17a , 17b.

In the first embodiment shown in FIG. 3, the anchoring part 13 may comprise a nose 13b projecting towards the pulley 15, to which the first flexible link 15a is fixed, and a body 13c comprising the support edges 13a and extending diverging from the nose 13b opposite the pulley 15.

The first elastic branches 18 can be connected to the nose 13b, on either side of it.

The intermediate parts 17 of the elastic arms may have first and second longitudinal edges 17c, 17d, respectively towards the pulley 15 and opposite the pulley 15.

CH 714 771 A2 The first elastic branches 18 can be connected to the intermediate parts 17 at the internal longitudinal end of said intermediate parts, in the vicinity of the second longitudinal edges 17d.

The second elastic branches 19 can be connected to the intermediate parts 17 at the outer longitudinal end of said intermediate parts, in the vicinity of the first longitudinal edges 17c. The second elastic branches 19 can extend from the intermediate parts 17, in front of the external end of said intermediate parts 17 and opposite the pulley 15, up to respective ends connected to the supports 20.

Claims (13)

The mechanical energy storage device 8 may further comprise a second elastic structure 8b which is symmetrical with said first elastic structure 8a with respect to the axis of rotation 16 of the pulley 15, the storage device for mechanical energy 8 further comprising a second flexible link 15b adapted to wind on the pulley 15 when said pulley 15 is rotated in the first direction R1 and to unwind from the pulley 15 when said pulley rotates in the second direction R2 , the second flexible link 15b extending from the pulley 15 to a free end secured to an anchoring part 13 belonging to the second elastic structure 8b, said anchoring part 13 of the second elastic structure 8b being distant pulley 15 at most when said second elastic structure 8b is in the rest position and the second elastic structure 8b being shaped so that the anchoring part 13 of the second elastic structure 8b is movable in translation in said direction of movement 14. Optionally, the first and second flexible links 15a, 15b can be formed in one piece. claims 1. Mechanical energy storage device (8) comprising at least a first elastic structure (8a) and an actuatable control member for elastically deforming the first elastic structure (8a) from a rest position in order to there accumulate mechanical energy, characterized in that the control member is a pulley (15) rotatably mounted about an axis of rotation (16) and on which is fixed a first flexible link (15a) suitable for s' wind on the pulley (15) when said pulley (15) is rotated in a first direction (R1) and to unwind from the pulley (15) when said pulley (15) rotates in a second direction (R2) opposite to first direction (R1), the first flexible link (15a) extending from the pulley (15) to a free end secured to an anchoring part (13) belonging to the first elastic structure (8a), said anchoring part (13) of the first elastic structure ( 8a) being moved away from the pulley (15) as much as possible when said first elastic structure (8a) is in the rest position and the first elastic structure (8a) being shaped so that the anchoring part (13) of the first elastic structure (8a) is movable in translation in a direction of movement (14) passing through the pulley (15). 2. Mechanical energy storage device (8) according to claim 1, in which the first elastic structure (8a) comprises two rigid supports (20) and two elastic arms (17-19) arranged in a V shape open towards the pulley (15), the elastic arms (17-19) extending diverging from said anchoring part (13) of the first elastic structure to external ends connected respectively to said rigid supports (20) of the first elastic structure (8a). 3. Mechanical energy storage device (8) according to claim 2, in which said anchoring part (13) of the first elastic structure (8a) is rigid, each elastic arm (17-19) of the first structure elastic (8a) comprises a rigid intermediate part (17) and first and second elastic branches (18, 19), said rigid intermediate part (17) being connected respectively to said anchoring part (13) of the first elastic structure ( 8a) and to one of said rigid supports (20) of the first elastic structure (8a) respectively by said first and second elastic branches (18, 19). 4. Mechanical energy storage device (8) according to claim 3, in which the first and second elastic branches (18, 19) are curved with a concavity turned opposite the pulley (15). 5. A mechanical energy storage device (8) according to claim 4, in which the anchoring part (13) of the first elastic structure (8a) has bearing edges (13a) facing the first elastic branches (18) of the first elastic structure (8a), said bearing edges (13a) of the anchoring part (13) being generally oriented towards the pulley (15) and being arranged beyond the first elastic branches (18 ) of the first elastic structure (8a) relative to the pulley (15). 6. A mechanical energy storage device (8) according to claim 5, in which each rigid intermediate part (17) of the first elastic structure (8a) has a convex edge (17a) opposite the first elastic branch (18 ) corresponding, the convex edge (17a) of said intermediate part (17) being adapted to come into rolling bearing against the first elastic branch (18) corresponding to the first elastic structure (8a) when the anchoring part (13) is sufficiently displaced towards the pulley (15) from the rest position, by applying the first elastic branch (18) against the bearing edge (13a) of the anchoring part (13). 7. Mechanical energy storage device (8) according to any one of the preceding claims 4 to 6, in which the supports (20) of the first elastic structure (8a) have bearing edges (20a) oriented towards the CH 714 771 A2 second elastic branches (19) of the first elastic structure (8a) and opposite the pulley (15) and towards the second elastic branches (19) of the first elastic structure (8a). 8. A mechanical energy storage device (8) according to claim 7, in which each rigid intermediate part (17) of the first elastic structure (8a) has an external convex edge (17b) opposite the second elastic branch ( 19) corresponding, the outer convex edge (17b) of said intermediate part (17) being adapted to come into rolling bearing against the second elastic branch (19) corresponding to the first elastic structure (8a) when the anchoring part (13 ) is sufficiently displaced towards the pulley (15) from the rest position, by applying said second elastic branch (19) against the bearing edge (20a) of the corresponding support (20). 9. Mechanical energy storage device (8) according to any one of claims 4 to 8, in which the supports (20) of the first elastic structure (8a) are resiliently displaceable relative to each other substantially perpendicular to the direction of movement (14). 10. Mechanical energy storage device (8) according to any one of the preceding claims, in which the first elastic structure (8a) extends in a plane perpendicular to the axis of rotation (16) of the pulley ( 15). 11. Mechanical energy storage device (8) according to any one of the preceding claims, in which the first elastic structure (8a) is monolithic. 12. Mechanical energy storage device (8) according to any one of the preceding claims, further comprising a second elastic structure (8b) which is symmetrical with said first elastic structure (8a) relative to the axis of rotation. (16) of the pulley (15), the mechanical energy storage device (8) further comprising a second flexible link (15b) adapted to be wound on the pulley (15) when said pulley (15) is driven in rotation in the first direction (R1) and to unwind from the pulley (15) when said pulley rotates in the second direction (R2), the second flexible link (15b) extending from the pulley (15) to a free end integral with an anchoring part (13) belonging to the second elastic structure (8b), said anchoring part (13) of the second elastic structure (8b) being at a maximum from the pulley (15) when said second elastic structure (8b) is zero n rest position and the second elastic structure (8b) being shaped so that the anchoring part (13) of the second elastic structure (8b) is movable in translation in said direction of movement (14). 13. Mechanical energy storage device (8) according to claim 12, wherein the first and second flexible links (15a, 15b) are formed in one piece.