Escapement of a timepiece movement, return element for an escapement of a timepiece, timepiece movement, and timepiece equipped with such a movement

Abstract

The invention relates in particular to a return element in the balance wheel (10) of a timepiece, replacing the spiral spring. This return element comprises a rake (21) provided with a toothed area (22) arranged to engage with a balance pinion (20). The rake (21) comprises an axis of rotation (24) enabling it to move between two extreme positions, called working positions, separated by a rest position. The return element also comprises two springs (26) arranged to urge the rake (21) towards its rest position. Each spring (26) is formed by an elastic blade (27) arranged to store energy and then restore it to the rake. The elastic blades operate alternately so that they are never operating simultaneously. The invention also relates to an escapement comprising such a return element, to a timepiece movement comprising this return element, and to a timepiece comprising such a movement.

Description

[Technical Field]

[0001] The present invention relates to the field of horology, and more particularly to the field of miniature mechanical horology. Its subject is to replace the spiral spring as a return member for the balance wheel by a component that is easier to manufacture, does not have the drawbacks of a hairspring, and can be adapted to existing escapement systems in miniature horological devices.

[0002] More particularly, the invention relates to an escapement for a clockwork movement, comprising a balance wheel, an escape wheel, a lever and a balance wheel return element, and further to a return element for a timepiece movement, comprising an escapement provided with a balance wheel, an escape wheel and a lever.

[0003] The invention further relates to a timepiece movement comprising an escapement provided with a balance wheel, an escape wheel, a lever and a balance wheel return member.

[0004] Finally, the invention relates to a timepiece equipped with a movement, escapement or return member as defined above. [Background technology]

[0005] Fixed horological devices, whether giant clocks, wall clocks or table clocks, have provided sufficient precision for centuries thanks to the pendulum, which derives its precision from gravity acting on a return element to return the pendulum to its dead point. Fixed timepieces take advantage of gravity, which is constant.

[0006] Early experiments for small horological devices were carried out with the addition of a crown escapement and a foliot balance as a return device. This system failed to provide satisfactory accuracy, and substantial improvements were only made after the invention of the spiral spring.

[0007] However, spiral springs are far more inefficient than gravity and their performance is far from constant. In addition to their very delicate manufacture, their most important drawbacks are the variations in vertical position and also the variations in the connection between contraction and relaxation of the rotation, which in technical terms are called the rise and fall angles. Despite all the research, a satisfactory solution to the disadvantages has not yet been found in terms of their form and materials.

[0008] Therefore, despite all the research into the escapement, and also into the balance wheel or other components, their arrangement and function, it is not possible to overcome the limitations of the hairspring.

[0009] Several improvements have been explored to replace the spiral spring in clockwork movements. Among them, Swiss Patent No. 34983 can be mentioned. In this patent, the clockwork movement includes a toothed rake acting on the balance pinion. The rake has a split rod that pivots on a shaft located at the end of the split rod, opposite the rake's teeth. The timepiece movement includes an elastic blade that is fixed to one end of a plate and has a protrusion near the other end. The protrusion is designed to slide in a slot in the split rod in the rake. The rake, split rod, and elastic blade work together to form the balance wheel's return member.

[0010] In this implementation, the elastic blade must be able to store energy when deformed by the movement of the rake. It must then return this energy to move the rake in the opposite direction, beyond its dead center or rest position. Maintenance of the movement and friction compensation are achieved by cooperation between the impulse surface of the escape wheel and the pallet of the lever.

[0011] The implementation described in the aforementioned patent presents several challenges. The resilient blade and split rod are not in the same plane. A protrusion protrudes from the resilient blade so that it can be placed in a slot in the split rod. Movement of the protrusion in the slot causes twisting of the resilient blade as well as friction, which results in significant energy loss.

[0012] Furthermore, the elastic blade must meet two contradictory constraints: on the one hand, its stiffness must be high enough to store a sufficient amount of energy while it is deforming under the influence of the balance wheel movement, and to release this energy when the elastic blade returns to its rest position. This amount of energy must also compensate for losses associated with the friction of the protrusions in the slots and with twisting of the elastic blade.

[0013] On the other hand, this stiffness must be low enough to allow the rake to move sufficiently and to allow an angular movement of the balance wheel of at least 300°.

[0014] A resilient blade that is too stiff can prevent large angular movements of the rake because it will tend to return the rake to its dead center after a relatively small angular movement. A resilient blade that is not stiff enough cannot store enough energy to allow the balance wheel to continue its movement.

[0015] Furthermore, if the elastic blade is too stiff, this movement cannot be initiated. In fact, this movement can only be initiated when the pallet of the lever reaches the impulse surface of the escape wheel. If the elastic blade is too stiff, this is not possible.

[0016] Using the systems described in the aforementioned patents, elastic blades already in existence or made with current materials and techniques cannot use the principles of the present invention, as their stiffness is too high to allow for sufficiently large movements of the balance wheel.

[0017] The stiffness of the spring depends in particular on its effective length, and a solution that would allow reducing the stiffness of the elastic blade would probably be to lengthen it. A typical spiral spring has 12 to 15 coils. In particular, in a portable timepiece, such as a typical wristwatch, it is not possible to accommodate an elastic blade that is long enough to obtain a functional return member.

[0018] The invention described in Swiss Patent No. 34983 attempts to solve the specific problems of spiral springs by creating a symmetrical return member that avoids the problems associated with the asymmetry of spiral springs, but the results obtained cannot be used in wristwatches of the wristwatch type.

[0019] Swiss Patent No. 19698 also describes in one of its embodiments a rake acting on a balance pinion. As in the above-mentioned Swiss Patent No. 34983, the rake is connected to an elastic rod, the deformation of which is supposed to allow the balance pinion to rotate.

[0020] The invention described in this patent has the same problems as those described in the aforementioned patent, which makes it impossible to put this invention into practice.

[0021] It would be advantageous to find a solution to provide a balance wheel actuating member with the purpose of replacing the spiral spring and its disadvantages, which is easier to manufacture than a hairspring, is symmetrical, allows starting of the timepiece movement, its size is compatible for use in conventionally sized wristwatches, and does not have the disadvantages of the implementation of the invention described in the prior art. [Prior art documents] [Patent documents]

[0022] [Patent Document 1] Swiss Patent No. 34983 [Patent Document 2] Swiss Patent Invention No. 19698 Summary of the Invention [Problem to be solved by the invention]

[0023] The disadvantages of the return members in the prior art are eliminated by the return member of the present invention.

[0024] The object of the present invention is to provide a return member which reacts equally to movement of the balance wheel in both directions, which is not obstructed in the vertical position, and which is not as fragile or delicate to handle as a spiral spring. [Means for solving the problem]

[0025] These objects are achieved by an escapement for a clockwork movement as defined in the preamble and characterized in that the balance wheel is integral with the balance wheel pinion, and that the return member of the balance wheel comprises a rake provided with toothed sections arranged to work with the balance wheel pinion. This rake comprises an axis allowing it to rotate between two extreme positions, called working positions, separated by a rest position. This return member further comprises a return mechanism comprising two springs arranged to urge the rake towards its rest position.

[0026] The object of the invention is also achieved by a return member as defined in the preamble, characterized in that it comprises a rake provided with a toothed section arranged to work with a balance pinion, the rake comprising a shaft allowing it to rotate between two extreme positions separated by a rest position, called working positions, and two springs arranged to urge the rake towards its rest position.

[0027] The object of the invention is further realized by a timepiece movement as defined in the preamble and characterized in that the balance wheel is integrated with the balance wheel pinion, and that the return member of the balance wheel comprises a rake provided with a toothed area arranged to work with the balance wheel pinion. This rake comprises an axis allowing it to rotate between two extreme positions, called working positions, separated by a rest position. This return member further comprises a return mechanism comprising two springs arranged to urge the rake towards its rest position.

[0028] Finally, the object of the invention is achieved by a timepiece comprising a movement, an escapement or a return member as defined above.

[0029] According to the invention, unlike a spiral spring, the return member is not fixed to the balance wheel, but the connection of the return member with the balance wheel is made by a mechanical gearing.

[0030] This return member comprises a toothed portion, hereafter called a rake, and a return mechanism including two springs made in the form of two elastic blades. The increased friction due to the gearing between the rake and the balance pinion is compensated according to the invention by reducing the disadvantages due to the spiral spring, its pressing against the stud, its indexing assembly, as well as the drawbacks explained at the beginning of this disclosure.

[0031] The escapement of the present invention comprises a rake provided with toothed sections which operates together with the balance pinion. The escapement of the present invention also comprises a return mechanism provided with two elastic blades. This rake pivots on its axis between two extreme positions, called working positions and corresponding to the maximum rotation of the balance wheel. These two extreme points are separated by a rest position.

[0032] When the rake is moved from its rest position, one of the elastic blades is deformed by the rake. This deformation has the effect of allowing the elastic blade to store energy. This energy is then used by the elastic blade to push the rake towards its rest position. Due to the configuration of the escapement, and in particular the lever, the energy supplied to the rake allows it to advance beyond its rest position. Once beyond this rest position, the elastic blade to which energy was provided no longer interacts with the rake. The other elastic blade similarly stores energy and then interacts to return the energy.

[0033] According to the invention, the return member has symmetry with respect to a plane passing through the axis of rotation of the balance wheel. Due to this symmetry, the force acting on the balance wheel when it moves in one direction of rotation is equal to the force acting on the balance wheel when it moves in the other direction of rotation. One of the disadvantages of the asymmetry of the hairspring is thereby eliminated.

[0034] The return member of the present invention is formed by two springs in the form of two elastic blades, or a return mechanism with spring blades acting on the rake. These elastic blades can be configured and positioned so that the rake can move only a small angle before one of the elastic blades acts on it and returns it to its rest position. This allows the watch movement to start and avoids the problem of it stopping on a stationary surface. The use of two elastic blades that are independent of each other and never operate simultaneously allows the rigidity of the return mechanism to be divided into two, which allows the blades to be of a sufficiently short length to allow installation in the case of a conventional-sized watch. This makes it possible to avoid the problems, particularly with the return member, described in Swiss Patents No. 34983 and 19698.

[0035] In the return member of the present invention, the two elastic strips are independent of each other, so that when one of the blades is deformed to store or return energy, the other elastic blade is stationary and does not interact with the rake, avoiding the problem of an elastic blade being too stiff, which can occur when two elastic blades act on the rake at the same time.

[0036] A rake consists of a section of a toothed wheel, which may usually have between 80 and 160 teeth. Assuming that the balance wheel performs a movement with an amplitude of 330° and that the balance wheel has 10 teeth, the angular movement is 37.125° for a rake corresponding to an 80-tooth wheel and 18.5625° for a rake corresponding to a 160-tooth wheel. The weak angular movement of the rake can be managed by a return mechanism, while allowing a large angular movement of the balance wheel.

[0037] The present invention and its advantages will be better understood with reference to the accompanying drawings and detailed description of specific embodiments. [Brief explanation of the drawings]

[0038] [Figure 1] Top view of a conventional Swiss lever escapement without a balance spring. [Figure 2] FIG. 2 is a side view of the escapement in FIG. 1. [Figure 3] FIG. 3 is a side view of the escapement of FIGS. 1 and 2 with the balance wheel shaft fitted with a pinion; [Figure 4] 4 is a top view of the part of the escapement in FIGS. 1 to 3 with the return member in a rest position according to a first embodiment of the invention; FIG. [Figure 5] 5 shows the return member of FIG. 4 in a rest position. [Figure 6] 5 shows the return member of FIG. 4 in an actuated position. [Figure 7] 10 is a top view of a variation of the return member of the present invention in a rest position. FIG. [Figure 7a]FIG. 8 is an enlarged view of a portion of FIG. [Figure 8] 8 is a top view of the return member of FIG. 7 in an actuated position. [Figure 9] 7 shows a return member similar to that of FIG. 6, which can effect adjustment of the position of the resilient blade. [Figure 10] 4A and 4B are diagrams illustrating deformations in a return member according to the invention in a rest position; [Figure 11] 11 shows the return member of FIG. 10 in an actuated position. [Figure 12] 10 shows another variant of the return member according to the invention in the rest position; FIG. [Figure 13] 10 shows another variant of the return member according to the invention in the rest position; FIG. [Figure 14] 10 shows another variant of the return member according to the invention in the rest position; FIG. [Figure 15] 15 shows the return member of FIG. 14 in an actuated position. [Figure 16] 16 shows a return member with an inner toothed rake and the same return mechanism as in FIGS. 14 and 15. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention relates in particular to escapements for clockwork movements. In the illustrated embodiment, the escapement comprises conventional and new components. The conventional components are depicted in FIGS. 1-3 as part of a Swiss lever escapement. This escapement comprises a balance wheel 10 pivoted on a balance wheel shaft 11, a lever 12 pivoted on a lever shaft 13, and an escape wheel 14 pivoted on an escape wheel shaft 15. The lever 12 further comprises a fork 16, which is actuated in a conventional manner, in particular by the balance wheel 10, and two anchors 17 acting on teeth 18 of the escape wheel 14. Unlike conventional escapements, this escapement does not include any spiral spring. It should be noted that a Swiss lever escapement is depicted here, and this escapement is the most commonly used in practice. However, the return member according to the present invention can also be used in any other escapement in which the balance wheel acts as the adjusting member.

[0040] The new parts include a return member 19 which replaces the spiral spring in its function.

[0041] The return device according to the invention can be integrated into an existing escapement or can form part of an escapement specially developed for this movement.

[0042] Referring specifically to FIG. 3, the balance wheel 10 used in the present invention comprises a balance wheel pinion 20 integral with the balance wheel shaft 11.

[0043] The return member 19 according to the invention comprises a rake 21 including a toothed section 22 and one or two arms 23. The rake 21 pivots about a rake axis 24 integral with the plate (not shown) of the clockwork movement. This rake can move on either side of its rest position between two extreme working positions in which the balance wheel 10 undergoes maximum clockwise or counterclockwise movement.

[0044] The return member 19 further comprises a return mechanism 25 including two springs 26, the operation of which will be explained below. These springs 26 consist of two elastic blades 27 in the illustrated embodiment.

[0045] In the embodiment illustrated in Figures 4 to 6, the rake 21 comprises two arms 23, one end of which is located at each end of the toothed section 22 and the other ends of which join near the axis of rotation 24 of the rake.

[0046] The rake 21 further comprises a rod 28 having one end close to the axis 24 of the rake and another end integral with a resilient blade 27.

[0047] The return member 19 can be mounted on a plate of the timepiece with two pins 30. These two pins 30 are arranged so that, depending on the position of the rake 21, the elastic blade 27 can rest against them.

[0048] In this embodiment, the rake 21, arm 23, rod 28, and resilient blade 27 are integrated and made in one piece.

[0049] Figures 4 and 5 illustrate the rake 21 in a rest position, and Figure 6 illustrates the rake 21 in an operating position.

[0050] When the balance wheel 10 is pivoted in one direction, for example in the operating position illustrated in FIG. 6, the balance wheel pinion 20 acts on the toothed section 22 of the rake 21, causing it to pivot in the opposite direction about the axis of rotation 24. This has the effect of deforming one of the elastic blades 27 relative to the corresponding pin 30 of the movement. This elastic blade 27 stores energy. The other elastic blade is free and does not interact with the rest of the movement or the other pin 30, and therefore does not oppose the rotation of the rake 21 or the balance wheel 10.

[0051] When the stress exerted by the elastic blade 27 is sufficient, after a certain angular movement of the rake 21, and therefore of the balance wheel 10, the blade returns energy, pivoting the rake in the other direction of rotation. This causes the balance wheel to rotate via the balance wheel pinion 20. Conventionally, the balance wheel 10 acts on the lever 12 to release the teeth 18 of the escape wheel 14. The impulse surface of the teeth on the escape wheel 14 acts on one of the anchors 17 of the lever 12 to supply energy to this lever, which transmits the energy to the balance wheel 10 via the fork 16. This energy is used by the balance wheel to pivot on the balance wheel axis 11, which causes the rake 21 to rotate on the axis 24, allowing the other elastic blade 27 of the return mechanism 25 to be loaded.

[0052] This alternating motion is similar to that produced by a hairspring, but unlike a hairspring, the elastic blades 27 are symmetrical with respect to each other when the rake is in its rest position, which implies that there is no difference in motion when the balance wheel 10 pivots clockwise or counterclockwise.

[0053] The pin 30 can be mounted eccentrically, thereby forming an adjusting element 29. This eccentricity makes it possible to modify the stiffness of the elastic blade 27 and thereby the amplitude of rotation of the rake 21 and of the balance wheel 10. More precisely, the two pins 30 of this adjusting element 29 can be moved, which makes it possible to adjust, within a certain margin, the distance between the elastic blade 27 and the axis of rotation 24 of the rake. This allows for a fine adjustment of the timepiece's progress. This fine adjustment of the timepiece's progress can be achieved via a screw balance wheel, as shown in the various drawings, or also by using an inertia block balance wheel.

[0054] 7 and 8, the return mechanism 25 is separate from and not integral with the rake 21. In this embodiment, the rake 21 pivots about its axis of rotation 24 and includes a single arm 23 connecting the rake's tooth section 22 to the axis of rotation 24.

[0055] The return mechanism 25 also comprises two elastic blades 27. These blades are generated independently of the rake 21. They are integrated into a support 32 fixed to the plate of the timepiece movement. Each of the elastic blades 27 works with one side of the rake arm 23. When the rake is moved in one direction, one of the elastic blades 27 leans against the corresponding side of the rake arm and deforms. This has the effect of allowing this elastic blade to store energy. The other elastic blade does not interact with the rake 21, so only the stiffness of one blade is involved, not both.

[0056] At the end of the movement of the rake 21, the resilient blade 27 returns energy and pushes the rake in the opposite direction, as explained above. The contact area between the resilient blade 27 and the rake arms 23 can be polished to minimize friction. The rake 21 and the resilient blade 27 are arranged in the same plane, and the resilient blades are only subjected to bending, not twisting, which allows energy to be stored and returned.

[0057] In the embodiment of FIG. 9, the resilient blade 27 is arranged on a movable support 33. The position of the movable support 33 can be adjusted on the plate of the watch movement. This adjustment is possible because the movable support 33 is provided with a toothed bar 34, and the plate is provided with an adjusting pinion 35. Rotation of the adjusting pinion 35 has the effect of moving the toothed bar 34 and therefore the position of the resilient blade 27. This makes it possible to modify the distance between the rake's rotation axis 24 and the contact point between the resilient blade 27 and the rake arm 23. This therefore modifies the force required to move the rake 21, which corresponds to an adjustment of the stiffness, or apparent stiffness, of the resilient blade 27.

[0058] Figures 10 and 11 illustrate a variant of the return member 19 according to the invention, in which the rake 21, the rake arm 23 and the resilient blade 27 of the return mechanism are made in one piece. In this embodiment, the timepiece comprises two pins 30, as described with reference to Figures 4 to 6. The two pins 30 are arranged so that the resilient blade 27 rests against them and can be deformed to store and return energy.

[0059] In this embodiment, the resilient blades 27 slide along the pins 30 and are not integral with them, so deformation in a bending mode occurs one blade at a time, and the two resilient blades do not deform simultaneously, buckle, or become too stiff to interfere with practical operation.

[0060] Figure 10 illustrates the rake 21 in a rest position, and Figure 11 illustrates the rake 21 in an active position. As can be seen particularly in Figure 11, only one blade at a time is active to store and return energy. In fact, only the resilient blade interacting with the pin 30 is active. The other resilient blade 27, shown on the left side of Figure 11, does not interact with the corresponding pin 30 and therefore is not involved in storing or returning energy at this stage in the rake's motion.

[0061] In the embodiment illustrated in Figures 12 to 15, the rake 21 is similar to that of Figures 7 to 9. The resilient blades 27 of the return mechanism 25 are not straight rods in the rest state, but form curves. Each end zone of the resilient blades 27 rests against one side of the arm 23 of the rake 21 and operates according to the same principle as described with reference to Figures 7 to 9.

[0062] This implementation has the advantage of making it possible to increase the length of the elastic blades 27 and therefore reduce their stiffness, without having to increase the size of the watch in which this return member is to be housed. The blades illustrated in Figures 12 and 13 differ in their width and in the position of contact between the elastic blade and the arm of the rake. The choice of a particular shape for the blades depends in particular on the space available in the movement.

[0063] In the embodiment illustrated in Figures 14 and 15, the elastic blade 27 forms folds in the form of bellows. This embodiment is interesting because it makes it possible to create a blade of long extension without requiring a large amount of available space in the case of the timepiece. In this respect, it approaches the extension of a spiral spring without the associated disadvantages.

[0064] The embodiment of Figures 12-15 is also interesting because the position of the contact point between the actuated spring blade 27 and the rake arm 23 moves with the movement of the rake 21. In particular, as can be seen by comparing Figures 14 and 15, which respectively show the rake 21 in its rest position and its actuated position, when the rake 21 is at or approaching its rest position, the contact point between one of the resilient blades 27 and the rake arm 23 is very close to the rake's axis of rotation 24. Therefore, the resilient blade 27 offers very little resistance to the rake 21, which allows for easy initiation of the movement without risk of jamming. As illustrated in Figure 15, when the rake 21 pivots, the shape of the resilient blade means that the contact point between the actuated resilient blade 27 and the rake arm 23 moves in the direction of the toothed section 22, away from the rake's axis of rotation 24. The opposing force of the elastic blade against the rake increases, which increases the energy that the elastic blade can store. Thus, the energy of the return mechanism 25 is not linear with the movement of the rake 21 and is very weak when the rake 21 is close to its rest position. This not only allows for easy starting of the movement, but also optimal storage and return of energy.

[0065] In the embodiment of Figure 16, the rake 21 is provided with internal toothing. The return mechanism 25 is identical to that of Figures 14 and 15. This is interesting because part of the rake is located on the other side of the balance shaft 11 relative to the rake's axis of rotation 24. This saves space and can be useful in small watch cases and / or when the space dedicated to the escapement is limited.

[0066] To enable the movement to start during lifting and to avoid problems with stopping on a stationary surface, it is advisable not to apply stress or weak stress to the arms 23 of the rake 21 when the rake 21 is in its rest position at dead center. This can be done in several ways. According to one method, the shape of the resilient blade 27 itself is provided for this purpose, as explained with reference to FIGS. 14 and 15. According to another variant, for example, illustrated in FIGS. 7 and 8, a slight gap can be provided between the resilient blade 27 and the rake arms 23 when the rake is at dead center. This gap is particularly visible in FIG. 7a, which shows, in greatly enlarged form, the contact zone between the resilient blade 27 and the rake arms 23, as illustrated in FIG. 7. In this way, when the rake is at dead center, no force is applied to the rake by the return mechanism 25. Force begins to be applied to the rake when it starts to move.

[0067] Alternatively, the timepiece movement may be provided with an adjustment element 29, such as an eccentric pin 30 illustrated in Figures 5 and 6, making it possible to position the elastic blade 27 in a suitable position, which can then be adjusted and corrected as required.

[0068] According to a preferred embodiment, stress can begin to be applied to the arm 23 of the rake 21 when the balance wheel 10 is pivoted by approximately 10°. Such a rotation makes it possible to position one of the lever's anchors on the impulse surface of one of the escapement teeth, which avoids blocking the movement and allows it to start.

[0069] The rake 21 is shown with two arms 23 in Figures 4-6 and a single arm in the other figures. A specific shape of the resilient blade is shown for each embodiment. Combinations of various embodiments are also possible. For example, it is possible to use the resilient blade illustrated in Figures 12-16 with a two-arm toothed rake as illustrated in Figures 4 and 6.

[0070] Similarly, adjustment elements such as eccentrics or movable supports can be added to the various illustrated embodiments.

Claims

1. An escapement for a clockwork movement, comprising a balance wheel (10) pivoted on an axis of rotation (11), an escape wheel (14), a lever (12), and a return member (19) for said balance wheel, said escapement comprising: The balance wheel (10) is integrated with the balance wheel pinion (20); The return member (19) of the balance wheel a rake (21) provided with a toothed section (22) arranged to work with said balance pinion (20) and with an axis (24) enabling it to rotate between two extreme positions, called working positions, separated by a rest position; and a return mechanism (25) consisting of two springs (26) arranged to urge the rake (21) towards its rest position, the springs (26) storing energy and including elastic blades (27) arranged to return energy to the rake (21); and only one of the resilient blades (27) stores energy and then returns energy to the rake (21) while the other resilient blade (27) is stationary; The escapement of a clockwork movement is characterized by:

2. 2. An escapement for a clockwork movement according to claim 1, characterized in that, when the rake is in its rest position, the spring (26) is arranged symmetrically with respect to a plane passing through the axis of rotation (11) of the balance wheel and the axis of rotation (24) of the rake.

3. A return element (19) for a timepiece movement, comprising an escapement provided with a balance wheel (10), an escape wheel (14) and a lever (12), a rake (21) provided with toothed sections (22) arranged to work with a balance pinion (20), said rake (21) including an axis (24) enabling it to rotate between two extreme positions, called working positions, separated by a rest position; two springs (26) arranged to urge the rake (21) towards its rest position, the springs (26) including elastic blades (27) arranged to store and return energy to the rake (21); only one of the resilient blades (27) stores energy and then returns energy to the rake (21) while the other resilient blade (27) is stationary; A return member characterized by:

4. 4. A return member according to claim 3, characterized in that, when the rake is in its rest position, the spring (26) is arranged symmetrically with respect to a plane passing through the axis of rotation (11) of the balance wheel and the axis of rotation (24) of the rake.

5. 4. A return member according to claim 3, characterized in that the rake (21) has an annular portion formed at one end of each arm (23) of the rake (21), and the toothed section (22) is provided inside the annular portion.

6. 4. A return member according to claim 3, characterized in that said resilient blade (27) is integrated with said toothed section.

7. 4. A return member according to claim 3, characterized in that the elastic blade (27) is arranged to rest against the arm (23) of the rake (21).

8. A timepiece movement comprising an escapement provided with a balance wheel (10), an escape wheel (14), a lever (12) and a return member (19) for said balance wheel, said timepiece movement comprising: The balance wheel (10) is integrated with a balance wheel pinion (20); The return member (19) of the balance wheel a rake (21) provided with a toothed section (22) arranged to work with said balance pinion (20), said rake (21) having an axle (24) enabling it to rotate between two extreme positions, called working positions, separated by a rest position; and a return mechanism (25) comprising two springs (26) arranged to urge the rake (21) towards its rest position and including an elastic blade (27) arranged to store and return energy to the rake (21); and only one of the resilient blades (27) stores energy and then returns energy to the rake (21) while the other resilient blade (27) is stationary; A timepiece movement characterized by:

9. 9. A timepiece movement according to claim 8, characterized in that it comprises at least two pins with which the elastic blades interact alternately during the movement of the rake around its axis of rotation (24).

10. A regulating element (29) of the escapement, An adjustment element for adjusting the distance between the elastic blade (27) and the rotation axis (24) of the rake.

9. A timepiece movement according to claim 8, characterized in that it comprises:

11. 11. A timepiece movement according to claim 10, characterized in that the adjusting element (29) of the escapement comprises at least two pins (30) movable on a plate of the timepiece movement and interacting with the spring (26).

12. A timepiece comprising a timepiece movement according to any one of claims 8 to 11.

Images