Stepped anchor for escapement mechanism
The anchor's unique positioning of the fork and arms at separate heights on the pivot axis addresses assembly and engagement challenges in escapement mechanisms, enhancing stability and efficiency while reducing space requirements.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ETA SA MFG HORLOGERE SUISSE
- Filing Date
- 2025-12-08
- Publication Date
- 2026-06-30
AI Technical Summary
Conventional escapement mechanisms in mechanical watches face challenges in simultaneously achieving precise positioning of the anchor with the escapement and balance wheel, leading to difficulties in assembly and engagement, particularly when using flexible guides with non-intersecting blades, which result in reduced amplitude and higher frequency vibrations.
The anchor is designed with the fork and arms positioned at separate heights along the pivot axis, allowing the balance wheel and escapement moving parts to be arranged at different heights, facilitating engagement and reducing space requirements, with specific distances defined between these positions.
This configuration ensures stable and efficient engagement between the anchor, balance wheel, and escapement parts, minimizing space usage and maintaining consistent oscillation frequency, thereby improving assembly and operational stability.
Smart Images
Figure 2026108568000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a stepped ankle for a watch escapement mechanism, further to an escapement mechanism, and to a watch movement comprising such an ankle.
Background Art
[0002] In most mechanical watches, the energy required to rotate the hands (e.g., the minute hand and the hour hand) is stored in a barrel and then distributed by a spring-loaded escapement system, which comprises a flywheel called a hairspring combined with a spring in the form of a strip wound around a spiral called a fusee.
[0003] The hairspring is attached at its inner end to a spindle that rotates with the escapement, and at its outer end to a hairspring holder that fits onto a hairspring hook attached to a fixed bar (or cock) itself.
[0004] An escapement mechanism comprising an ankle driven by a low-amplitude oscillating movement with two or three pallets engaging the teeth of the escapement movable member maintains the rotation of the escapement and counts the oscillations of the escapement. When engaged in this way, the escapement movable member is forced into a stepwise rotational movement at a frequency determined by the oscillation frequency of the ankle, which itself is set to the oscillation frequency of the spring-loaded escapement.
[0005] When using a conventional escapement mechanism, the oscillation frequency is about 4 Hz or approximately 28,800 oscillations per hour (A / h). Skilled watchmakers aim to ensure that the spring-loaded escapement oscillates continuously at equal intervals (meaning that the speed remains constant).
[0006] The ankle of the escapement mechanism is designed to provide mechanical coupling means between the escapement and the escapement movable member. Therefore, the positioning of the escapement is important to ensure that the escapement engages correctly with the other two components.
[0007] Generally, the anchor is formed by a single-piece body comprising a fork that engages with an ellipse on the balance wheel and at least two arms that engage with the escapement mechanism, often each fitted to a pallet stone. The body of the anchor fits on a central shaft, which has pivots at each end. During assembly, the pivots are inserted into bearings arranged within a rod or plate.
[0008] Today, the hairspring can be replaced by a flexible guide as a spring forming a virtual pivot. Flexible guides with a virtual pivot can significantly improve clock resonators. The simplest is a cross-blade pivot consisting of two guides with linear, intersecting blades. These two blades can be three-dimensional in two different planes, or two-dimensional in the same plane, and if two-dimensional, they are soldered together at the intersection. However, there are also RCC (Remote Center Compliance) guides with non-intersecting blades, which have linear blades that do not intersect. Such resonators are described in European Patent No. 14199039 and European Patent No. 16155039.
[0009] However, when using such a flexible guide, the balance wheel has a much smaller amplitude and a rotation angle of approximately 20°, whereas when using a hairspring, the rotation angle is 330°, and the balance wheel vibrates at a much higher frequency than the balance wheel fitted onto the hairspring.
[0010] Therefore, new escapement mechanism configurations that function with a speed control mechanism incorporating a flexible guide have been invented.
[0011] In most mechanical movements, the escapement gear axis, the anchor axis, and the spring-loaded balance axis are in the same plane. Viewed from above, the positions of these three axes form a straight line. This is known as a perfectly aligned center. However, this arrangement is rather cumbersome.
[0012] In certain watch movement configurations, the positions of the three axes form a curve. In other words, the escapement, anchor, and balance wheel are not aligned but arranged in a triangle, each at the vertices of the same triangle. Such an arrangement allows for a reduction in the size of the watch movement.
[0013] Generally, the anchor fork and pallet jewel on the anchor are positioned at the same height within the movement. Furthermore, since the fork engages with the ellipse on the balance wheel and the pallet jewel engages with the teeth on the escapement gear, the fork and pallet jewel must remain separated from each other so as not to collide at all between the ellipse and the teeth on the escapement gear. The above explains why a "center alignment" in a straight line is commonly used.
[0014] Therefore, on the one hand, the relative position between the anchor and the escapement gear, specifically the center distance, must be precisely defined. On the other hand, the relative position between the anchor and the balance wheel, specifically the center distance, must also be precisely defined.
[0015] Since the fork and the clincher generally belong to the same part (ankle) and engage at substantially the same height, it is difficult to satisfy both requirements simultaneously. [Prior art documents] [Patent Documents]
[0016] [Patent Document 1] European Patent No. 14199039 [Patent Document 2] European Patent No. 16155039 [Overview of the Initiative] [Problems that the invention aims to solve]
[0017] The present invention aims to provide an anchor for a new type of escapement mechanism, an anchor that avoids the aforementioned drawbacks, and more specifically, an anchor that facilitates the assembly of the anchor, as well as the engagement of the anchor with the escapement movable and balance wheel. [Means for solving the problem]
[0018] To achieve this objective, the present invention relates to an anchor for a watch escapement mechanism, comprising a fork designed to engage with an ellipse on a balance wheel, an inlet arm and an outlet arm designed to engage with an escapement movable part, and a pivot into which the anchor is fitted, wherein the anchor is arranged on the pivot in two separate locations such that the fork is arranged at a first height and the inlet arm and outlet arm are arranged at a second height, and the two heights are separated by a predetermined distance along the axis of the pivot.
[0019] The present invention is noteworthy in that the forks, inlet arm, and outlet arm are arranged on the central axis at two separate locations, so that the forks are positioned at a first height and the arms at a second height, with the two heights separated by a predetermined distance.
[0020] Thus, such an anchor allows the balance wheel and escapement moving parts to be arranged at different heights within the watch movement. For example, the escapement moving parts can be arranged above a plate at the bottom of the movement, and the balance wheel can be arranged at the top of the movement. A stepped anchor allows engagement with the balance wheel and escapement moving parts in such an arrangement, especially when the anchor, balance wheel, and escapement gears are configured to take up minimal space.
[0021] According to a particular embodiment of the present invention, the first height is arranged at the lower end of the axial axis.
[0022] According to a specific embodiment of the present invention, the predetermined distance is between one-fourth and three-fourths of the length of the spindle, preferably between one-third and two-thirds of the length of the spindle, or even within a range substantially equal to half of the length of the spindle.
[0023] According to a specific embodiment of the present invention, the second height is arranged substantially at the center of the spindle.
[0024] According to a specific embodiment of the present invention, the anchor comprises a fork designed to engage an ellipse on the temp, and an inlet arm and an outlet arm designed to engage a detent escapement movable member.
[0025] The present invention also relates to a detent escapement mechanism comprising a detent escapement movable member and such an anchor.
[0026] The present invention also relates to a timepiece movement comprising a plate, a temp, a temp receiver, a flexible guide, wherein the temp is suspended by the flexible guide, and such a detent escapement mechanism, and the anchor engages an ellipse on the temp on one hand and a detent escapement movable member on the other hand.
[0027] According to a specific embodiment of the present invention, the spindle on the anchor is fitted to pivot within the timepiece movement, and the spindle comprises a first pivot arranged at a first end of the spindle and a second pivot arranged at a second end of the spindle.
[0028] According to a specific embodiment of the present invention, the first pivot is fitted to pivot within the plate.
[0029] According to a specific embodiment of the present invention, the second pivot is fitted to pivot within the temp receiver.
[0030] [[ID=
[0031] Other features and advantages of the present invention will become more apparent by reading the following description of specific embodiments of the invention, which are provided simply as illustrative, non-limiting examples, and by looking at the accompanying drawings. [Brief explanation of the drawing]
[0032] [Figure 1] This is a schematic top view of a clock module equipped with a regulating mechanism and an escapement mechanism. [Figure 2] Figure 1 is a schematic side view of the clock module. [Figure 3] Figures 1 and 2 are schematic cross-sectional views of a watch movement with the watch module. [Figure 4] A schematic perspective view of the anchor according to the present invention is shown. [Modes for carrying out the invention]
[0033] In Figures 1 and 2, the clock module 10 includes an escapement mechanism 50 associated with a regulating mechanism 60.
[0034] The speed control mechanism 60 comprises a balance wheel 35 and a rotatable flexible guide 32 for the balance wheel 35, while the escapement mechanism 50 comprises an escapement movable part 30 and an anchor 21.
[0035] The balance wheel 35 is shaped like a bone, fitting into the longitudinal portion 36 and into the arc-shaped side portions 37 at each end of the longitudinal portion 36. The balance wheel 35 further comprises a stopper concentric with a virtual axis of rotation fitted in the center of the longitudinal portion 36, and screws 39 arranged within the side portions 37 for setting the balance wheel's inertia.
[0036] The balance wheel 35 is fitted onto the flexible guide 32, allowing it to perform rotational vibrations around a virtual axis of rotation. The flexible guide 32 is directly connected to the balance wheel 35.
[0037] The flexible guide 32 comprises at least two flexible blades 37 arranged in series, forming a double pivot that increases the rotation angle of the spool 35; in this example, it comprises two pairs of intersecting flexible blades 37.
[0038] Ankle 21 engages with two arms 11 and 12, and its ends form two pawl stones that engage with teeth 18 on the first escapementary animal 30.
[0039] Arms 11 and 12 on the ankle 21 engage with the escapemental animal 30 and alternately act with teeth 18 on the escapemental animal 30 to adjust the speed.
[0040] The ankle 21 also has a longitudinal portion 14 that extends laterally, which fits with the fork 22 at its end and engages with the ellipse 23 on the balance wheel 35.
[0041] The ankle 21 is substantially perpendicular to the longitudinal portion 14 and the fork 22 and includes a pivot 5 that can be fitted so as to rotate as it moves.
[0042] The anchor 21 comprises an elongated body 31 that extends radially, and the body 31 is arranged to engage with a stopper (not shown in the figure). The purpose of the stopper is to prevent the anchor 21 from rotating too much.
[0043] The elongated body 31 is positioned at essentially the same height as the entrance arm 11 and exit arm 12 on the ankle 21.
[0044] According to the present invention, the fork 22, as well as the inlet arm 11 and outlet arm 12, are arranged at two locations on the central axis 5. The fork 22 is arranged at a first height on the central axis 5, while the inlet arm 11 and outlet arm 12 are arranged at a second height on the central axis 5.
[0045] In this way, the two heights are separated by a predetermined distance D0 along the axis of the heart axis 5. Preferably, the predetermined distance D0 is between one-quarter and three-quarters of the length of the heart axis, preferably between one-third and three-thirds of the length of the heart axis, or even substantially half the length of the heart axis.
[0046] For example, the first height is positioned substantially at the lower end of the axial axis, while the second height is positioned substantially at the center of the axial axis.
[0047] Preferably, the axis 5 begins from the plate 2 and has a length substantially corresponding to the height of the watch movement.
[0048] The escapement mechanism 50 further comprises a second clockwork mechanism 20 which is engaged with the first escapement mechanism 30. For example, the second clockwork mechanism 20 is a seconds mechanism. The teeth 14 on the second clockwork mechanism 20 engage with the pinion 3 on the first escapement mechanism 30.
[0049] The balance wheel 35 includes an ellipse 23 that extends below the balance wheel 35 and engages with the fork 22 on the ankle 21. The ellipse 23 is attached to the balance wheel 35.
[0050] The centers of the perimeter 35, the escapementary animal 30, and the anchor 21 are aligned on a curved line. This is in contrast to conventional escapement mechanisms, in which this line is substantially straight, and the anchor is aligned on this line between the perimeter and the escapementary animal.
[0051] Therefore, the temporomandibular joint 35, the escapement mechanism 30, and the ankle 21 are arranged at the vertices of the triangle, respectively.
[0052] The curvature has an angle of less than 90°, preferably less than 70°, or even less than 60°. Thus, the temporomandibular joint 35, the escapemental animal 30, and the ankle 21 are arranged without taking up much space.
[0053] In Figure 3, the clock modules from Figures 1 and 2 are arranged in detail within the watch movement 1 for the watch.
[0054] In addition to the clock module 10, the clock movement 1 includes plates 2 and rods for supporting components within the clock module 10.
[0055] In detail, the watch movement 1 includes a balance bridge 4 arranged above the balance wheel 35. Thus, the balance wheel 35 oscillates between the plate 2 and the balance bridge 4. For example, the balance bridge 4 includes an upper stopper that prevents the balance wheel 35 from moving vertically.
[0056] The clock movement 1 also includes an escapement rod 6 that keeps the axis on the escapement mechanism 30 pivot.
[0057] The escaped animal 30 is fitted so as to pivot between the plate 2 and the escaped animal rod 6.
[0058] The core shaft 5 comprises a first pivot 7 arranged at the first end of the core shaft 5 and a second pivot 8 arranged at the second end of the core shaft 5.
[0059] The first pivot 7 is fitted to pivot on the plate 2, and the second pivot 8 is fitted to pivot within the balance spring 4. In this way, the anchor 21 is fitted to pivot between the balance spring 4 and the plate 2. The pivot 5 extends beyond the balance spring 35.
[0060] To achieve this objective, the balance support 4 includes a first bearing 13 that acts as a stopper for the balance wheel 35 in the event of an impact and is concentric with a virtual axis of rotation defined by the flexible guide 32, and a second bearing 15 for the anchor 21. The distance D1 between the center of the first bearing 13 and the center of the second bearing 15 is predetermined to allow for optimal engagement between the fork 22 on the anchor 21 and the ellipse 23 on the balance wheel 35.
[0061] Plate 2 comprises a third bearing 16 for the top 35, a fourth bearing 17 for the central shaft 5 on the anchor 21, and a fifth bearing 9 for the escapemental animal 30. The distance D2 between the center of the fourth bearing 17 and the center of the fifth bearing 9 is predetermined to allow for optimal engagement between the arms 11, 12 on the anchor 21 and the escapemental animal 30.
[0062] The escapement rod 6 is equipped with a sixth bearing 24 for pivoting on the escapementary animal 30.
[0063] This arrangement of the ankle 21 ensures, on the one hand, the engagement between the arms 11 and 12 on the ankle 21 and the escapemental animal 30, and on the other hand, the engagement between the fork 22 and the ellipse 23. In practice, the possibility of the axial axis 5 being too tilted relative to the plate 2 is very low.
[0064] Since the anchor 21 and the balance wheel 35 are positioned between the plate 2 and the balance wheel support 4, the distance D1, which is the center distance defined between the second pivot 8 on the balance wheel 35 and the pivot of the anchor 21 on the balance wheel support 4, is constant and is very unlikely to fluctuate during assembly.
[0065] Similarly, the distance D2, which is the central distance defined between the first pivot 7 on the ankle and the pivot on the escapemental movable 30 on the plate 2, is constant and does not fluctuate during assembly.
[0066] Naturally, the present invention is not limited to the embodiments described with reference to the drawings, and modified forms can be envisioned without departing from the scope of the present invention. [Explanation of Symbols]
[0067] 1. Watch movement 2 plates 3 pinion 4. Tempura receiver 5 core axis 6 escapement rod 7. The First Axis 8. The Second Axis 9. Fifth bearing 10 Clock Modules 11 Entrance Arm 12 Exit Arm 13. First bearing 14 Longitudinal portion 15. Second bearing 16. Third bearing 17. The fourth bearing 18 teeth 20 Second Clock-Moving Animal 21 Uncle 22 Forks 23 Ellipse 24. The sixth bearing 30 Escapericomorphs, First Escapericomorphs 31 Ankle's long, slender body 32 Flexible Guide 35 tempura 36 Longitudinal portion 37 Side section, flexible blade 39 screws 50 Escapement mechanism 60 Speed governor mechanism D0 predetermined distance D1 Distance between the center of the first bearing and the center of the second bearing D2 Distance between the center of the fourth bearing and the center of the fifth bearing
Claims
1. An anchor (21) for a watch escapement mechanism (50), comprising a fork (22) designed to engage with an ellipse (23) on a balance wheel (35), an inlet arm (11) and an outlet arm (12) designed to engage with an escapement movable part (30), and a spindle (5) into which the fork (22), the inlet arm (11), and the outlet arm (12) are fitted, wherein the fork (22), the inlet arm (11), and the outlet arm (12) are arranged on the spindle (5) at two separate locations, the fork (22) being arranged at a first height on the spindle (5), and the arms (11, 12) being arranged at a second height on the spindle (5), and the two heights being separated by a predetermined distance (D0) along the axis of the spindle (5).
2. The ankle according to claim 1, characterized in that the first height is arranged at the lower end of the central axis (5).
3. The ankle according to claim 1, characterized in that the predetermined distance (D0) is between one-quarter and three-quarters of the length of the core axis (5), preferably between one-third and three-thirds of the length of the core axis, or even more substantially half of the length of the core axis.
4. The ankle according to claim 1, characterized in that the second height is substantially aligned to the center of the central axis (5).
5. An escapement mechanism comprising an escapementable animal (30) and an anchor (21) as described in claim 1.
6. A watch movement comprising a plate (2), a balance wheel (35), a balance bridge (4), and a flexible guide (32), wherein the balance wheel (35) is suspended by the flexible guide (32), and as a result, the balance wheel (35) can oscillate about a virtual axis between the plate (2) and the balance bridge (4), wherein the watch movement comprises the escapement mechanism described in claim 5, and the anchor (21) engages with an ellipse (23) on the balance wheel (35) on the one hand and with the escapement mechanism (30) on the other hand.
7. The watch movement according to claim 6, wherein the pivot shaft (5) on the anchor (21) is fitted to pivot within the watch movement (1), and the pivot shaft (5) comprises a first pivot (7) arranged at the first end of the pivot shaft (5) and a second pivot (8) arranged at the second end of the pivot shaft (5).
8. The clock movement according to claim 7, characterized in that the first pivot (7) is fitted to the plate (2) so as to pivot.
9. The clock movement according to claim 7, characterized in that the second pivot (8) is fitted to pivot within the balance bridge (4).
10. The watch movement according to claim 6, characterized in that the balance wheel (4), the escapement mechanism (30), and the anchor (21) are arranged such that lines extending through the center of the escapement mechanism (30), the center of the balance wheel (35), and the axis (5) on the anchor (21) form a curve at an angle of less than 90°, preferably less than 70°, or even less than 60°.