Enhanced lubrication of the watch escapement
The escapement wheel with corner cuts on its teeth addresses the challenge of lubrication maintenance in timepieces, enhancing lubrication distribution and wear resistance, thus prolonging the mechanism's life.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ETA SA MFG HORLOGERE SUISSE
- Filing Date
- 2025-12-17
- Publication Date
- 2026-07-02
AI Technical Summary
Lubrication of the mechanism between the oscillator and the train in a timepiece is difficult to maintain over its lifetime, requiring precise distribution of lubricant without excess, especially for components like balance pivots, pawl forks, and escape wheel teeth.
The escapement wheel in the watch mechanism is designed with corner cuts on its teeth, varying in geometric orientation and shape, allowing for improved lubrication and distribution of lubricant, ensuring even wear and longevity.
The corner cuts on the escapement wheel teeth enhance lubrication, ensuring consistent lubrication and reducing wear, thereby extending the mechanism's lifespan with minimal additional machining costs.
Smart Images
Figure 2026110557000001_ABST
Abstract
Description
Technical Field
[0005] , ,
[0001] The present invention comprises at least one escape wheel arranged to pivot about an escape axis and engage with a pawl including an entry pawl stone and an exit pawl stone, or engage with a mechanism including an entry pawl stone and an exit pawl stone, or engage with a release for holding a lock, or engage with a notched cylinder including an entry lip and an exit lip, the escape wheel comprising a plurality of teeth extending substantially radially with respect to the escape axis on both sides of a median plane orthogonal to the escape axis, each tooth comprising a substantially radial locking surface and a substantially tangential impact surface extending between a point and a heel, the heel defining a back surface on the opposite side of the locking surface with respect to the tooth, and relates to a clock escape mechanism.
[0002] The present invention also relates to a timepiece, particularly a wristwatch, comprising such an escape mechanism.
[0003] The present invention relates to the field of escape mechanisms for timepieces.
Background Art
[0004] Lubrication of the mechanism between the oscillator and the train is difficult to ensure over the lifetime of a timepiece. The lubricant must be distributed in exactly the right amount, without the slightest excess that would necessarily contaminate the entire timepiece mechanism. This mainly involves moving the initial amount of lubricant deposited in the timepiece movement when it was first manufactured, and carefully distributing the lubricant across the contact surfaces, whether pivot surfaces or distribution surfaces. However, it is difficult to effectively lubricate the surfaces of the components involved in counting, balance pivots, pawl forks and lifts, and escape wheel teeth.
Summary of the Invention
Problems to be Solved by the Invention
[0005] An object of the present invention is to provide means for improving the lubrication of an escape mechanism.
Means for Solving the Problems
[0006] For this purpose, the present invention relates to the watch escapement mechanism described in claim 1.
[0007] The present invention also relates to a timekeeping device, particularly a wristwatch, equipped with such an escapement mechanism.
[0008] The purpose, advantages, and features will be better understood by referring to the attached drawings and reading the detailed description below. [Brief explanation of the drawing]
[0009] [Figure 1] This is a schematic perspective view of the escapement wheel in the escapement mechanism according to the present invention, wherein some or all of the teeth are provided with corner cuts in different directions on both sides of the midline surface of the tooth portion in order to improve lubrication. [Figure 2] This is an enlarged view of Figure 1, showing three different types of corner cuts. [Figure 3] This is another enlarged view of Figure 1, showing two types of corner cuts opposite the midline plane of the tooth, according to the first and second shapes. [Figure 4] This is a schematic plan view of a conventional example of teeth on an escapement wheel. [Figure 5] Figure 1 is an elevation view of the escapement wheel, and includes three different corner cut shapes: the first and second shapes shown in Figure 4, which are tangential to the impact surface on the outer circumference of the escapement wheel, and the third shape, which is substantially parallel to the pivot axis of the escapement wheel and is also seen in Figures 1 and 2. [Figure 6] This is an enlarged plan view of the corner cut related to the third shape. [Figure 7] This is a schematic cross-sectional view of a specific tooth profile through the pivot axis of the escapement wheel, where the impact surface of the tooth is edged by a corner cut according to a first shape, or according to a second shape, or according to both the first and second shapes, and the perpendicular position of the impact surface in the direction of the pivot axis differs for each tooth. [Figure 8]This figure shows an example of the periodic distribution of tooth positioning in Figure 7 across the outer circumference of the escapement wheel, involving a sequence of rising impact surfaces followed by a return to the lowest level for the next cycle. [Figure 9] Figure 7 shows an example of the periodic distribution of tooth positioning across the outer circumference of the escapement wheel, with a sequence of rising impact surfaces followed by a return to the lowest level for the next cycle, and Figure 8 is a cross-sectional view showing the distribution of the tooth impact surfaces. [Figure 10] This figure shows another modified example similar to Figure 8, which also has teeth similar to those in Figure 7, but with an alternating sequence of rising and falling teeth. [Figure 11] This figure shows yet another modification of the escapement wheel, in which the impact surface comprises substantially tangential slots defined by inclined surfaces, one of which conforms to a first shape and the other to a second shape. [Figure 12] This is a schematic front view of a timepiece, particularly a wristwatch, equipped with such an escapement mechanism. [Modes for carrying out the invention]
[0010] This invention aims to improve the lubrication of the contact between the escapement wheel and a reaction mechanism such as a pawl.
[0011] Accordingly, the present invention relates to a watch escapement mechanism 100 comprising at least one escapement wheel 1 mounted to pivot around an escapement axis DE and arranged to engage with a distribution mechanism downstream of the oscillator. This distribution mechanism may, but is not limited to, comprise a pawl with an entry lift and an exit lift. This distribution mechanism may comprise an entry pawl stone and an exit pawl stone, or a release that holds a lock, or a notched cylinder with an entry lip and an exit lip, or other features.
[0012] The doffing wheel 1 has a plurality of teeth 2 extending substantially radially with respect to the doffing shaft DE and on both sides of the median plane PM perpendicular to the doffing shaft DE. Each of these teeth 2 has a substantially radial locking surface 3 and a substantially tangential impact surface 4 extending between a point 5 and a heel 6, and the aforementioned heel 6 defines a back surface 7 on the opposite side of the locking surface 3 with respect to the body of the tooth 2. As seen in FIG. 4, the point 5 is in contact with the dresser on the nail.
[0013] According to the present invention, the doffing wheel 1 has at least two teeth 2, and each tooth 2 has at least one corner cut 20 connected to the impact surface 4 of the tooth 2. Each of the corner cuts 20 on at least two different teeth 2 has a different geometric spatial direction with respect to the respective impact surface 4 on the tooth 2 holding this corner cut 20.
[0014] The surface of each corner cut 20 forms an obtuse angle with the impact surface, and due to the corner cut, droplets or micro-droplets of lubricant can easily pass through and are enabled to remain on the tooth 2 for a long time.
[0015] The fact that the geometric orientations of the corner cuts 20 are different, or simply that they are arranged alternately, means that the teeth on the doffing wheel and the opposing lifter or nail do not always wear at the same place.
[0016] Therefore, a more random positioning of the corner cuts on the outer periphery of the doffing wheel is advantageous for the long-term durability of the mechanism.
[0017] More specifically, at least one tooth 2 has such a corner cut 20 with a substantially flat surface on an inclined surface intersecting the doffing shaft DE.
[0018] More specifically, at least one tooth 2 holding at least one corner cut 20 has a corner cut 20 according to a first shape 21 extending towards the first upper side 11 of the doffing wheel 1.
[0019] More specifically, at least one tooth 2 holding at least one corner cut 20 comprises a corner cut 20 according to a second shape 22 that extends towards the second lower side 12 of the retraction wheel 1.
[0020] More specifically, the retraction wheel 1 comprises both at least one tooth 2 holding at least one corner cut 20 according to a first shape 21 that extends towards the first upper side 11 of the retraction wheel 1 and at least one tooth 2 holding at least one of the aforementioned corner cuts 20 according to a second shape 22 that extends towards the second lower side 12 of the retraction wheel 1.
[0021] More specifically, at least one corner cut 20 on the first tooth 2 extends towards the first upper side 11 of the retraction wheel 1 according to the first shape 21 essentially on the first side of the median plane PM, and at least one corner cut on the second tooth 2 extends towards the second lower side 11 of the retraction wheel 1 according to the second shape 22 essentially on the second side of the median plane PM.
[0022] Even more specifically, at least one corner cut 20 on the first tooth 2 extends towards the first upper side 11 of the retraction wheel 1 completely according to the first shape 21 on the first side of the median plane PM, and at least one corner cut 20 on the second tooth 2 extends towards the second lower side 11 of the retraction wheel 1 completely according to the second shape 22 on the second side of the median plane PM.
[0023] More specifically, at least one tooth 2 comprises at least one corner cut 20 according to the first shape 21 or the second shape 22, the corner cut 20 is connected to the impact surface 4, is substantially circular, and defines a first edge 25 located in a plane perpendicular to the retraction axis DE.
[0024] More specifically, the aforementioned corner cut 20 protrudes in the direction of the escapement axis DE and extends over the height HC of the corner cut, which is included in 50% to 66% of the protrusion of the remaining height HR of the impact surface 4.
[0025] More specifically, at least one tooth 2 includes a corner cut 20 extending along a third shape 23. This third shape may extend on both sides of the median plane PM and have a substantially flat surface in a plane substantially parallel or substantially perpendicular to the escapement axis DE, or extend in the direction of the escapement axis DE over the entire tooth height HD of the tooth 2 having the corner cut 20, or extend in relation to the impact surface 4, be substantially straight, and define a second trailing edge 26 located in a plane substantially parallel or substantially perpendicular to the escapement axis DE. The geometric extension of this corner cut 23 may intersect with teeth 2 other than those having an obtuse corner cut 23 that forms an obtuse angle with the impact surface 4, or with teeth 2 having an acute corner cut 23. More specifically, the escapement wheel 1 comprises both at least one tooth 2 having an inwardly recessed acute-angled corner cut 23 whose geometric extension intersects with a tooth 2 that holds a corner cut 20, and at least one tooth 2 having an obtuse-angled corner cut 23 whose geometric extension intersects with a tooth 2 other than the tooth 2 that holds the corner cut 20.
[0026] More specifically, the corner cut 23 extends over a width LC of the corner cut that is smaller than the resulting width LR of the impact surface 4, in a flat projection in the direction of the escapement axis DE on a plane parallel to the median plane PM, and the resulting width LR must be large in order to have a sufficiently long second impact phase.
[0027] Figure 7 schematically shows a modification in which the tooth 2 has a specific profile and the impact surface 4 on the tooth 2 is edged by a corner cut according to a first shape 21 such as guide mark A, or according to a second shape 22 such as guide mark D, or according to both the first shape 21 and the second shape 22 such as guide marks B and C, the vertical position of the impact surface 4 in the direction of the pivot axis DE is variable according to the tooth type, thereby having impact surfaces 4 offset perpendicularly to each other from guide marks B and C.
[0028] Figures 8 and 9 show examples of the periodic distribution of the positioning of teeth A, B, C, and D in Figure 7, along with the sequence of rising impact surface 4 and subsequent return to the lowest level for the next cycle, across the outer circumference of the escapement wheel. Sections A, B, C, D, and E in Figure 9 show the position of impact surface 4 at each step compared to the tooth height HD.
[0029] Figure 10 shows another modified example similar to Figure 8, which also has teeth similar to those in Figure 7, but with an alternating sequence of rising and falling.
[0030] Figure 11 shows yet another modification of the escapement wheel, in which the impact surface comprises substantially tangential slots defined by inclined surfaces, one of which conforms to a first shape 21 and the other to a second shape 22. This is equivalent to two distinct impact surfaces. In particular, the slots can be varied in height and depth to improve lubrication.
[0031] More specifically, at least one tooth 2 is provided with a corner cut 20 having a flat surface.
[0032] More specifically, each tooth 2 having a corner cut 20 has a corner cut 20 with a flat surface.
[0033] More specifically, at least one tooth 2 is provided with a corner cut 20 having a concave surface.
[0034] More specifically, each tooth 2 having a corner cut 20 has a corner cut 20 with a concave surface.
[0035] More specifically, at least one tooth 2 is either micro-striped or has a corner cut 20 with at least one micro-cavity and a surface designed to retain lubricant.
[0036] More specifically, the escapement wheel 1 comprises a plate having a total thickness ET in the direction of the escapement axis DE, which is greater than the tooth height HD of each tooth 2 in the direction of the escapement axis DE.
[0037] More specifically, the shape of the corner cut 20 is aperiodic around the outer circumference of the escapement wheel 1.
[0038] More specifically, at least one tooth 2 is provided with at least one oil reservoir 30 in the vicinity of the aforementioned impact surface 4.
[0039] More specifically, at least one tooth 2 comprises at least one corner cut 20 connected to the aforementioned impact surface 4, and at least one oil reservoir 30 in the vicinity of the aforementioned corner cut 20.
[0040] More specifically, each corner cut has a surface finish of 0.05 micrometers Ra to 0.8 micrometers Ra.
[0041] More specifically, the escapement wheel 1 has an even number of teeth 2.
[0042] The present invention also relates to a timekeeping device 1000, particularly a wristwatch, equipped with such an escapement mechanism 100.
[0043] This invention is suitable for conventional machining of watch escapement wheels and ensures improved lifespan of the escapement mechanism with minimal additional machining costs. [Explanation of Symbols]
[0044] 1. Escapement wheel 2 teeth 3. Locking surface 4 Impact surface 5 points 6 heels 7 Back 11. Top of the first 12 Second lower side 20 Corner cut 21 First Shape 22 Second Shape 23 Third Shape 25 Circular edge 26 Trailing edge 30 Oil puddles 100 Watch escapement mechanism 1000 clock DE escapement axis PM median plane HC corner cut height HD tooth height HR remaining height ET total thickness
Claims
1. The escapement includes at least one escapement wheel (1) mounted to pivot around the escapement shaft (DE) and arranged to engage with a pawl including an entry pawl and an exit pawl, or with a mechanism including an entry pawl and an exit pawl, or with a release that holds a lock, or with a notched cylinder including an entry lip and an exit lip, wherein the escapement wheel (1) has a plurality of teeth (2) extending substantially radially with respect to the escapement shaft (DE) on both sides of a central plane (PM) perpendicular to the escapement shaft (DE), each having a substantially radial locking surface (3), and a point (5) and a heel (6) A watch escapement (100) comprising a substantially tangential impact surface (4) extending between the teeth (2) and the lock surface (3), wherein the heel defines a back surface (7) opposite to the lock surface (3) with respect to the teeth (2), the escapement wheel (1) comprising at least two teeth (2), each holding at least one corner cut (20) connected to the impact surface (4), and each of the corner cuts (20) on at least two different teeth (2) having a different geometric spatial orientation with respect to the respective impact surface (4) on the teeth (2) holding the corner cut (20).
2. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) has a corner cut (20) having a substantially flat surface on an inclined surface intersecting the escapement shaft (DE).
3. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) holding at least one of the corner cuts (20) has a corner cut (20) extending toward the first upper side (11) of the escapement wheel (1).
4. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) holding at least one of the corner cuts (20) has a corner cut (20) extending toward the second lower side (12) of the escapement wheel (1).
5. The watch escapement mechanism (100) according to claim 3 or 4, characterized in that the escapement wheel (1) comprises both at least one tooth (2) holding at least one corner cut (20) extending toward the first upper side (11) of the escapement wheel (1) and at least one tooth (2) holding at least one corner cut (20) extending toward the second lower side (12) of the escapement wheel (1).
6. The watch escapement mechanism (100) according to claim 5, characterized in that at least one of the corner cuts (20) on the first teeth (2) extends toward the first upper side (11) of the escapement wheel (1) essentially according to a first shape (21) on the first side of the median plane (PM), and at least one of the corner cuts (20) on the second teeth (2) extends toward the second lower side (12) of the escapement wheel (1) essentially according to a second shape (22) on the second side of the median plane (PM).
7. The watch escapement mechanism (100) according to claim 6, characterized in that at least one tooth (2) is connected to the impact surface (4) according to the first shape (21) or the second shape (22) and comprises at least one corner cut (20) defining a first substantially circular edge (25) located in a plane perpendicular to the escapement shaft (DE).
8. The watch escapement mechanism (100) according to claim 2, characterized in that the corner cut (20) protrudes in the direction of the escapement axis (DE) and extends over a height (HC) of the corner cut that is included in 50% to 66% of the protrusion of the remaining height (HR) of the impact surface (4).
9. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) extends according to a third shape (23) on both sides of the median plane (PM) and has a corner cut (20) having a substantially flat surface in a plane parallel to the escapement axis (DE).
10. The watch escapement mechanism (100) according to claim 9, wherein at least one of the teeth (2) has a corner cut (20) that extends in the direction of the escapement axis (DE) and the corner cut (20) in accordance with a third shape (23) over the entire tooth height (HD) of the tooth (2) having the corner cut (20).
11. The watch escapement mechanism (100) according to claim 9, characterized in that at least one tooth (2) is connected to the impact surface (4) according to the third shape (23) and comprises at least one corner cut (20) defining a second substantially linear trailing edge (26) located in a plane parallel to the escapement axis (DE).
12. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) has a corner cut (20) which includes at least one sloped surface including a gradient.
13. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) comprises the impact surface (4) including a substantially tangential slot defined by an inclined surface.
14. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) has the corner cut (20) including a flat surface.
15. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) has the corner cut (20) including a concave surface.
16. The watch escapement mechanism (100) according to claim 1, characterized in that at least one of the teeth (2) is minutely striped or has a corner cut (20) having at least one minute cavity and a surface designed to hold a lubricant.
17. The watch escapement mechanism (100) according to claim 1, characterized in that the escapement wheel (1) comprises a plate having a total thickness (ET) in the direction of the escapement axis (DE) that is greater than the tooth height (HD) of each of the teeth (2) in the direction of the escapement axis (DE).
18. The clock escapement mechanism (100) according to claim 1, characterized in that the shape of the corner cut (20) is aperiodic on the outer circumference of the escapement wheel (1).
19. The watch escapement mechanism (100) according to claim 1, characterized in that at least one tooth (2) is provided with at least one oil reservoir (30) in the vicinity of the impact surface (4).
20. The watch escapement mechanism (100) according to claim 19, characterized in that at least one tooth (2) comprises at least one corner cut (20) connected to the impact surface (4) and at least one oil reservoir (30) in the vicinity of the at least one corner cut (20).
21. The watch escapement mechanism (100) according to claim 1, characterized in that each of the corner cuts has a surface finish of 0.05 micrometers Ra to 0.8 micrometers Ra.
22. The watch escapement mechanism (100) according to claim 1, characterized in that the escapement wheel (1) has an even number of teeth (2).
23. A timekeeping device (1000) comprising at least one clock escapement mechanism (100) according to claim 1.