Tool and method for separating balance spring after winding and heat treatment

Abstract

To provide a method for separating a balance spring, based on mechanically crushing the balance spring.SOLUTION: One aspect of the invention relates to a tool (100) for separating plates (123) of a balance spring (1, 2, 3) after winding. The tool has substantially parallel lower and upper rolling surfaces (4, 5) that are movable vertically or longitudinally relative to one another to deform the plate (123) by ovalization to cause the plate (123) to undergo a rolling movement between the rolling surfaces (4, 5). The invention further uses this tool (100) to separate the balance springs (1, 2, 3) from the plates and mechanically crush the balance springs within their elastic range, initiating the sequence of compressing and rolling the plate (123).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a tool for separating substantially cylindrical or annular balance spring plates after winding and heat treatment, the tool being configured to initiate or carry out separation of the balance spring.

[0002] The present invention further relates to a method for separating the balance spring from the plates after winding and heat treatment.

[0003] The present invention relates to the manufacture of balance springs for timepieces, in particular oscillator springs. [Background technology]

[0004] The oscillator balance spring is made by winding 3-6 metal blades to form a balance spring plate. This creates an Archimedes spiral with a regular pitch between each coil. The balance spring plate is then heat treated (set) to retain this spiral shape. This method increases the contact surface between the small metal plates and can complicate the separation step, since balance springs are known to "stick". This problem is particularly prevalent when the balance spring is made from a titanium-based alloy, but steel balance springs do not usually have separation problems.

[0005] The traditional method for separating balance springs involves placing them inside a small cardboard box and manually banging the box against a hard surface, while a more industrial method uses a tapping machine that utilizes a cam and spring to repeatedly impact the balance spring.

[0006] Another approach is to chemically generate a layer of a specific compound that significantly reduces adhesion between the blades and allows for good separation, but this method limits the possibilities to compensate for the thermal coefficient of the balance spring. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention proposes to develop an alternative method for separating the balance springs, based on mechanically crushing the balance springs before they pass through the tapping machine. [Means for solving the problem]

[0008] To this end, the invention relates to a tool for separating substantially cylindrical or annular balance spring plates after winding and heat treatment, the tool being adapted to initiate or carry out the separation of the balance spring.

[0009] According to the invention, the tool has a lower first rolling surface and an upper second rolling surface, said lower first rolling surface and said upper second rolling surface being parallel or substantially parallel to each other or to a base plane and movable relative to each other in a longitudinal direction parallel to said base plane on the one hand and in a vertical direction perpendicular to said base plane on the other hand, and configured to clamp said plate between a lower generatrix and an upper generatrix under the action of at least one actuator, said actuator being adapted to clamp said plate between said lower first generatrix and said upper second generatrix. the first lower rolling surface and the second upper rolling surface are adapted to move closer together to deform the plate by ovalisation, and the first lower rolling surface and the second upper rolling surface are adapted to undergo a rolling movement between the first lower rolling surface and the second upper rolling surface on a substantially cylindrical periphery of the plate under the action of at least one actuator, the actuator being adapted to induce relative longitudinal movement between the first lower rolling surface and the second upper rolling surface.

[0010] Another aspect of the invention relates to a method for separating the balance spring from the plates after winding and heat treatment.

[0011] According to the invention, such a tool is used to mechanically crush the plate within its elastic range, determining the minimum and maximum crushing rates of the substantially cylindrical circumferential surface of the plate, performing at least one rolling sequence on the plate in a compressed position, determining the minimum and maximum rotations per sequence, determining the minimum and maximum cumulative rotations for a set of sequences including a predetermined number of sequences, and placing one of the plates between the lower first rolling surface and the upper second rolling surface of the tool under the action of an operator or a robotized manipulator, and performing for each sequence a first step of compressing the plate by a predetermined vertical stroke, a second step of moving the lower first rolling surface and the upper second rolling surface relative to each other through a predetermined longitudinal stroke, and a third step of moving the lower first rolling surface and the upper second rolling surface apart in a spaced position in which the plate is not subjected to any compressive stress.

[0012] The objects, advantages and features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a side view of a balance spring plate including multiple balance springs wound on top of each other and staggered along their length after winding and heat treatment. [Diagram 2] FIG. 2 is a perspective view of a balance spring plate of FIG. 1. [Diagram 3] FIG. 2 shows a schematic side view of a tool according to the invention, which has an upper rolling surface and a lower rolling surface, both of which are supported on the outside of the balance spring plate of FIG. 1 through the upper and lower generatrix of said plate. [Figure 4] In a similar manner to FIG. 3, the same tool is shown diagrammatically with a mandrel for limiting radial movement of the plate. [Diagram 5] 4 shows diagrammatically the same tool in a similar form to FIG. 3, with the plates positioned edge-to-edge on the lower rolling surface and the upper rolling surface spaced-apart from the plates. [Figure 6] 5, the same tool is shown diagrammatically with the upper rolling surface adjacent the lower rolling surface and supported by the plate while compressing the plate, the plate being ovalized by the compression. [Figure 7] 5 shows, in a similar form to FIG. 6, the same tool, with the upper and lower rolling surfaces moving longitudinally relative to each other and supported by the plate while compressing it, the plate being ovalized by the compression. [Figure 8] 8 shows, in a similar form to FIG. 7, the same tool, with the upper rolling surface now clear of the plate, causing the plate to return to a substantially cylindrical shape. [Figure 9] FIG. 2 shows a schematic perspective view of the same tool, which has two side plates on either side of the plate to limit the transverse play of the plate. [Figure 10] FIG. 10 shows, in a similar manner to FIG. 9, the same tool with a mandrel similar to FIG. 4, which is guided relative to a side plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention relates to a method for mechanically squeezing the plates of a wound and anchored balance spring within its elastic range, by means of which the separation rate of the balance spring can be significantly improved.

[0015] The drawings show a specific, but non-limiting, example of the application of the invention to a balance spring plate 123. The invention relates to the separation of balance springs 1, 2, 3 that make up this balance spring plate 123. It can be understood that this example of three balance springs is purely illustrative and that the invention is applicable to any general balance spring plate.

[0016] It is important to note that the rolling by crushing involves the application of mechanical stress to the balance spring plates immediately after settling, which elastically deforms the balance spring plates, thereby contributing to the separation of the balance spring blades and facilitating the separation process. Therefore, it is important to note that rolling is not strictly a separation method, but a preliminary step that, if performed correctly, can significantly reduce the rejection rate in separation.

[0017] The plates of the wound and anchored balance spring are placed vertically, specifically end-to-end, in the vertical direction Z on a horizontal support in the plane XY. The tool 100 comprises a mechanical actuator, which crushes the plates by moving them in the vertical direction Z. This action generates compressive stresses at the poles of the balance spring plate 123 and tensile stresses at the equator. This tensile stress is locally utilized to contribute to pulling apart the blades of the balance springs 1, 2, 3. After the balance spring plate 123 has been crushed, the mechanical actuator generates a transverse displacement in the longitudinal direction X. This mechanical actuator can be the same one that initiates the crushing. This causes the balance spring plate 123 to rotate (hence the term "rolling") while maintaining the crushing in the vertical direction Z. This results in tensile stresses that continue to affect all parts of the blade as the balance spring plate 123 rolls. The blades also gradually slide against each other, which also contributes to the pulling-apart effect. After the longitudinal displacement is complete, the crushing ends and the balance spring returns to its initial shape. The tool then begins a reverse longitudinal displacement back to its initial position. This cycle is repeated multiple times to ensure that each section of the balance spring plate experiences multiple tensile stress stages.

[0018] This crushing and rolling process is controlled by several important parameters.

[0019] The crushing rate is an important parameter since it determines the intensity of the tensile stress that contributes to the blade separation. However, the crushing rate must not be too high in order to avoid plastic deformation of the balance spring plate 123. The crushing rate is preferably selected within the range of 1.5% to 5.6% of the diameter of the balance spring plate 123.

[0020] Thanks to the magnitude of the longitudinal displacement of the actuator, the extent of the area under tensile stress can be varied. To achieve effective rolling, it is important that all parts of the balance spring plate 123 are under tensile stress at some point in time. Typically, each cycle of lateral displacement causes a rotation of the balance spring plate in the range of 1 / 8 to 1 revolution.

[0021] The number of rolling cycles depends on both the longitudinal displacement of the actuator during each cycle and the length of the base of the rolling device. There is an optimum, since too few rolling cycles will have a very limited effect on improving the separation rate, while too many rolling cycles will mechanically lock the blades and prevent them from separating. The number of rotations varies within the range of 1 / 2 to 100, preferably 1 to 10, and more preferably 2 to 4.

[0022] The balance spring plate is inserted so that it rolls in the opposite direction to the Archimedes spiral, otherwise the ends of the blades at the periphery of the balance spring plate 123 may get caught on the base, causing plastic deformation of the balance spring.

[0023] It is advantageous to arrange a plate, in particular a plexiglass plate, whose role is to limit the displacement of the plate in the transverse direction Y, i.e. perpendicular to the rolling plane, while providing the necessary space for rolling with minimal friction in this direction. Such a plate also makes it possible to fix the blades to each other at regular intervals.

[0024] After the balance spring plate 123 has passed the tool 100 according to the invention constituting a rolling device, standard separation processes (cardboard box, tapping machine) can be successfully applied.

[0025] In particular, the invention is based on the use of a tool 100 for separating the substantially cylindrical or annular plates 123 of the balance springs 1, 2, 3 after winding and heat treatment. This tool 100 is intended to initiate or carry out the separation of the balance springs 1, 2, 3.

[0026] According to the invention, the tool 100 has a lower first rolling surface 4 and an upper second rolling surface 5 which are parallel or substantially parallel to each other and to a base plane XY and which can move relative to each other on the one hand in a longitudinal direction X parallel to the base plane XY and on the other hand in a vertical direction Z perpendicular to the base plane XY.

[0027] This first lower rolling surface 4 and this second upper rolling surface 5 are configured to clamp the plate 123 between a lower generatrix 1234 and an upper generatrix 1235 under the action of at least one actuator 6, 7, which is configured to bring the first lower rolling surface 4 and the second upper rolling surface 5 closer together and to deform the plate 123 by ovalization.

[0028] The first lower rolling surface 4 and the second upper rolling surface 5 are configured to cause the substantially cylindrical peripheral surface 10 of the plate 123 to undergo a rolling movement between the first lower rolling surface 4 and the second upper rolling surface 5 under the action of at least one actuator 6, 7 configured to impart a relative movement in the longitudinal direction X between the first lower rolling surface 4 and the second upper rolling surface 5.

[0029] In particular, the tool 100 comprises a control means 200 configured to initiate a vertical stroke in the vertical direction Z of the lower first rolling surface 4 relative to the upper second rolling surface 5 and to initiate a longitudinal stroke in the longitudinal direction X of the lower first rolling surface 4 relative to the upper second rolling surface 5.

[0030] In particular, the control means 200 is configured to initiate at least one sequence, which includes a first step of compressing the plate 123 by a predefined vertical stroke of the first actuator 6 after the plate 123 has been positioned between the lower first rolling surface 4 and the upper second rolling surface 5 by an operator or a robotized manipulator, a second step of moving the lower first rolling surface 4 and the upper second rolling surface 5 relative to each other through a predefined longitudinal stroke, and a third step of separating the lower first rolling surface 4 and the upper second rolling surface 5 from each other to a separated position in which the plate 123 is not subjected to any compressive stress.

[0031] In particular, said predetermined vertical stroke is within the range of 1.5% to 5.6% of the maximum diameter of the substantially cylindrical circumferential surface 10 of the plate 123 .

[0032] In particular, the predetermined longitudinal stroke is intended to impart a rotation of the plate 123 within the range of 1 / 8 turn to 1 turn.

[0033] In particular, the control means 200 is configured to initiate, in at least one sequence, a fourth step in which the lower first rolling surface 4 and the upper second rolling surface 5 are moved relative to each other to return them to the positions they occupied relative to each other in the first step.

[0034] In particular, the control means 200 is configured to initiate a number of such sequences resulting in cumulative rotations of the plate 123 within the range of 0.5 revolutions to 100 revolutions.

[0035] In particular, the control means 200 is configured to initiate a number of such sequences resulting in a cumulative rotation of the plate 123 within the range of 1 to 10 revolutions.

[0036] In particular, the control means 200 is configured to initiate a number of such sequences resulting in a cumulative rotation of the plate 123 within the range of 2-4 revolutions.

[0037] In particular, the tool 100 has at least one plate 400 with a transversely oriented flat surface for limiting the transverse stroke of the plate 123 in a transverse direction Y perpendicular to the longitudinal direction X and the vertical direction Z. In particular, the tool 100 has two such plates on either side of the plate 123, transversely spaced apart, for limiting the transverse stroke of the plate 123, at least one of which is optically transparent.

[0038] In particular, the tool 100 has a mandrel 300 that can be inserted into the plate 123 and that is configured to limit the stroke of the plate 123 when it is handled in the tool 100. In particular, the mandrel 300 is dimensioned such that for a given shape of the plate 123, a radial clearance occurs that is greater than a given vertical stroke, which is the maximum compression stroke initiated by the control means 200. In particular, this mandrel 300 is guided by recesses or trunnions in two such parallel plates 400.

[0039] In particular, the lower first rolling surface 4 is a surface of a rigid lower plate 40 and / or the upper second rolling surface 5 is a surface of a rigid upper plate 50 .

[0040] In a first alternative embodiment, the lower first rolling surface 4 and / or the upper second rolling surface 5 are flat surfaces.

[0041] In a second alternative embodiment, the lower first rolling surface 4 and / or the upper second rolling surface 5 have a corrugation. In particular, the corrugation is non-periodic.

[0042] In a second alternative embodiment, the orientation of the lower first rolling surface 4 and the upper second rolling surface 5 can be such that the inscribed planes on the plate 123 side are inclined at a predetermined angle that is less than 5°.

[0043] In particular, the tool 100 comprises a first actuator 6 configured to bring the lower first rolling surface 4 and the upper second rolling surface 5 closer together in the vertical direction Z, thereby deforming the plate 123 by ovalization.

[0044] In particular, the tool 100 comprises a second actuator 7 configured to impart a rolling movement to the substantially cylindrical peripheral surface 10 of the plate 123 on the lower first rolling surface 4 and the upper second rolling surface 5. In particular, the second actuator 7 is configured to initiate a relative movement in the longitudinal direction X between the lower first rolling surface 4 and the upper second rolling surface 5.

[0045] In particular, the second actuator 7 is combined with a first actuator 6, which is the only actuator included in the tool 100, and which is provided with switching means for separately initiating relative movement between the lower first rolling surface 4 and the upper second rolling surface 5 in the vertical direction Z or the longitudinal direction X.

[0046] In particular, the control means 200 is automated.

[0047] In particular, the control means 200 is manually operated.

[0048] The invention further relates to a method for separating the balance springs 1, 2, 3 from the plate 123 after winding and heat treatment.

[0049] According to the invention, such a tool 100 is used to mechanically crush a plate 123 within its elastic range, minimum and maximum crush rate values ​​are determined for the substantially cylindrical peripheral surface 10 of the plate 123, the plate 123 undergoes at least one rolling sequence in a compression position, minimum and maximum rotation values ​​are determined for each sequence, minimum and maximum cumulative rotation values ​​are determined for a group of sequences including a predetermined number of sequences, the plate 123 is placed between a first lower rolling surface 4 and a second upper rolling surface 5 of the tool 100 by the action of an operator or a robotized manipulator, and for each sequence the following steps are performed in sequence: That is, a first step is performed of compressing the plate 123 by a predetermined vertical stroke, a second step is performed of moving the lower first rolling surface 4 and the upper second rolling surface 5 relative to each other through a predetermined longitudinal stroke, and a third step is performed of separating the lower first rolling surface 4 and the upper second rolling surface 5 from each other to a separated position in which the plate 123 is not subjected to any compressive stress.

[0050] In particular, during said sequence the blades of the balance springs 1, 2, 3 are radially crushed at regular intervals. In another alternative embodiment, the blades of the balance springs 1, 2, 3 are radially crushed at irregular intervals between the lower first rolling surface 4 and the upper second rolling surface 5.

[0051] In particular, after carrying out multiple crushing operations by rolling according to this method, the balance springs 1, 2, 3 are mechanically separated by placing the plate 123 inside a cardboard box where it is impacted against a solid surface and / or by treating the plate 123 with a tapping machine which generates repeated impacts of the plate 123 against the balance springs 1, 2, 3.

[0052] In short, separation is assisted by crushing the material by rolling within its elastic range, a method that leaves no mark on the balance spring.

[0053] Thanks to this process of separating the balance springs using suitable tools, based on rolling crushing, it is possible to significantly increase the proportion of separated balance springs and therefore of working balance springs, relative to those made of titanium alloys. [Explanation of symbols]

[0054] 1, 2, 3 Balance spring 4 Lower first rolling surface 5 Upper second rolling surface 6, 7 Actuator 10 Circumferential surface 40 Lower Plate 50 Upper Plate 100 tools 123 Plate 200 Control Means 300 Mandrel 400 plates 1234, 1235 busbar

Claims

1. A tool (100) for separating a substantially cylindrical or annular plate (123) of a balance spring (1, 2, 3) after winding and heat treatment, comprising: said tool (100) being adapted to initiate or carry out the separation of said balance springs (1, 2, 3); The tool (100) has a lower first rolling surface (4) and an upper second rolling surface (5), said lower first rolling surface (4) and said upper second rolling surface (5) are parallel or substantially parallel to each other and to a base plane (XY) and can move relative to each other on the one hand in a longitudinal direction (X) parallel to said base plane (XY) and on the other hand in a vertical direction (Z) perpendicular to said base plane (XY), configured to clamp said plate (123) between a lower generatrix (1234) and an upper generatrix (1235) under the action of at least one actuator (6, 7), the actuators (6, 7) bring the lower first rolling surface (4) and the upper second rolling surface (5) closer together to deform the plate (123) by ovalization; said lower first rolling surface (4) and said upper second rolling surface (5) are configured to cause a substantially cylindrical peripheral surface (10) of said plate (123) to undergo a rolling movement between said lower first rolling surface (4) and said upper second rolling surface (5) under the action of at least one actuator (6, 7); The actuators (6, 7) are configured to impart relative movement of the lower first rolling surface (4) and the upper second rolling surface (5) in a longitudinal direction (X) therebetween. A tool (100) comprising:

2. The tool (100) comprises a control means (200) adapted to initiate a vertical stroke in a vertical direction (Z) of the lower first rolling surface (4) relative to the upper second rolling surface (5) and to initiate a longitudinal stroke in a longitudinal direction (X) of the lower first rolling surface (4) relative to the upper second rolling surface (5). The tool (100) of claim 1 .

3. The control means (200) a first step of compressing said plate (123) by a predefined vertical stroke of said first actuator (6) after said plate (123) has been placed between said lower first rolling surface (4) and said upper second rolling surface (5) by an operator or a robotized manipulator; a second step of moving the lower first rolling surface (4) and the upper second rolling surface (5) relative to each other through a predetermined longitudinal stroke; a third step of separating the lower first rolling surface (4) and the upper second rolling surface (5) from each other in a separated position in which the plate (123) is not subjected to any compressive stress; The method is configured to initiate at least one sequence including The tool (100) of claim 2.

4. The predetermined vertical stroke is within the range of 1.5% to 5.6% of the maximum diameter of the substantially cylindrical circumferential surface (10) of the plate (123). The tool (100) of claim 3.

5. The predetermined longitudinal stroke is configured to provide a rotation of the plate (123) in the range of 1 / 8 to 1 revolution. The tool (100) of claim 3.

6. The control means (200) are configured to initiate in said at least one sequence a fourth step of moving said lower first rolling surface (4) and said upper second rolling surface (5) relative to each other back to the positions they occupied relative to each other in said first step. The tool (100) of claim 3.

7. The control means (200) is configured to initiate a plurality of sequences resulting in cumulative rotations of the plate (123) within a range of 0.5 to 100 revolutions. The tool (100) of claim 3.

8. The control means (200) is configured to initiate a plurality of sequences resulting in cumulative rotations of the plate (123) within a range of 1 to 10 revolutions. The tool (100) of claim 7.

9. The control means (200) is configured to initiate a plurality of sequences resulting in cumulative rotations of the plate (123) in the range of 2 to 4 revolutions. The tool (100) of claim 8.

10. The tool (100) comprises at least one plate (400) with a flat surface oriented transversely in a transverse direction Y perpendicular to a longitudinal direction X and a vertical direction Z; The flat surface limits the transverse stroke of the plate (123). The tool (100) of claim 1 .

11. The tool (100) comprises two plates, transversely spaced apart on either side of the plate (123), for limiting the transverse stroke of the plate (123), at least one of which is optically transparent. The tool (100) of claim 10.

12. The tool (100) comprises a mandrel (300) insertable into the plate (123); The mandrel (300) is configured to limit the stroke of the plate (123) when handled in the tool (100). The tool (100) of claim 1 .

13. The mandrel (300) is dimensioned such that there is a radial clearance with respect to the plate (123) that is greater than the predetermined vertical stroke, which is the maximum compression stroke initiated by the control means (200). The tool (100) of claim 3.

14. The lower first rolling surface (4) is the surface of a rigid lower plate (40) and / or the upper second rolling surface (5) is the surface of a rigid upper plate (50). The tool (100) of claim 1 .

15. The lower first rolling surface (4) and / or the upper second rolling surface (5) are flat surfaces. The tool (100) of claim 1 .

16. The lower first rolling surface (4) and / or the upper second rolling surface (5) have corrugations. The tool (100) of claim 1 .

17. The corrugations are non-periodic The tool (100) of claim 16.

18. The orientation of the lower first rolling surface (4) and the upper second rolling surface (5) is such that the tangential planes on the sides of the plate (123) are inclined to each other at a predetermined angle of less than 5°. The tool (100) of claim 1 .

19. The tool (100) comprises a first actuator (6) configured to bring the lower first rolling surface (4) and the upper second rolling surface (5) closer together in a vertical direction (Z) to deform the plate (123) by ovalization. The tool (100) of claim 1 .

20. The tool (100) comprises a second actuator (7) configured to impart a rolling movement to the substantially cylindrical peripheral surface (10) of the plate (123) on the lower first rolling surface (4) and the upper second rolling surface (5). The tool (100) of claim 1 .

21. The second actuator (7) is configured to initiate relative movement in the longitudinal direction (X) between the lower first rolling surface (4) and the upper second rolling surface (5). The tool (100) of claim 20.

22. The second actuator (7) is combined with a first actuator (6), which is the only actuator included in the tool (100); The first actuator (6) comprises switching means for separately initiating a relative movement between the lower first rolling surface (4) and the upper second rolling surface (5) according to a vertical direction (Z) or a longitudinal direction (X). Tool (100) according to claims 19 and 20.

23. The control means (200) is automated. The tool (100) according to claim 2 and claim 1.

24. The control means (200) is manually operated. The tool (100) according to claim 2 and claim 1.

25. A method for separating a balance spring (1, 2, 3) from a plate (123) after winding and heat treatment, comprising the steps of: Providing a tool (100) according to claim 1 for mechanically crushing said plate (123) within its elastic range; Minimum and maximum crush rate values ​​are determined for the substantially cylindrical peripheral surface (10) of said plate (123); The plate (123) undergoes at least one rolling sequence in a compression position, A minimum and maximum rotation value is determined for each sequence, determining minimum and maximum cumulative rotation values ​​for a group of sequences that includes a predetermined number of sequences; said plate (123) being placed between said lower first rolling surface (4) and said upper second rolling surface (5) of said tool (100) by the action of an operator or a robotic manipulator; a first step of compressing said plate (123) with a predetermined vertical stroke; a second step of moving the lower first rolling surface (4) and the upper second rolling surface (5) relative to each other through a predetermined longitudinal stroke; a third step of separating the lower first rolling surface (4) and the upper second rolling surface (5) from each other in a separated position in which the plate (123) is not subjected to any compressive stress; for each sequence in turn.

26. During said sequence, the blades of the balance spring (1, 2, 3) are radially crushed at regular intervals between the lower first rolling surface (4) and the upper second rolling surface (5).

26. The method of claim 25.

27. After carrying out multiple rolling crushing operations according to the method, the balance springs (1, 2, 3) are mechanically separated from each other by placing the plate (123) in a cardboard box and impacting the cardboard box against a solid surface and / or by treating the plate (123) with a tapping machine which repeatedly impacts the balance springs (1, 2, 3) of the plate (123).

26. The method of claim 25.

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