Timepiece movement comprising a pallet assembly pivotably mounted in the balance bridge
The new escapement mechanism addresses the issue of collisions and suboptimal cooperation in mechanical watches by arranging the balance wheel, escapement wheel, and anchor in a bent configuration, ensuring precise center distances and improved operational efficiency.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ETA SA MFG HORLOGERE SUISSE
- Filing Date
- 2025-12-05
- Publication Date
- 2026-06-25
AI Technical Summary
Existing escapement mechanisms in mechanical watches struggle to precisely define and maintain the center-to-center distance between the anchor and the balance wheel, which is crucial for ensuring optimal cooperation between the anchor and the balance wheel, leading to potential collisions and suboptimal cooperation.
A new escapement mechanism design where the balance wheel, escapement wheel, and anchor form a bend with an angle of less than 90°, allowing the stem to extend above the balance wheel, separating the fork and pallet arms vertically, and precise center-to-center distances are maintained between the anchor and balance wheel, and the anchor and escapement wheel.
This design prevents collisions and ensures optimal cooperation between the fork and ellipse of the balance wheel, maintaining precise oscillation frequencies and reducing the risk of mechanical interference.
Smart Images
Figure EP2025085628_25062026_PF_FP_ABST
Abstract
Description
CLOCK MOVEMENT COMPRISING AN ANCHOR MOUNTED ON A PIVOT IN THE BALANCE BRIDGE Technical field of the invention
[0001] The present invention relates to a clockwork movement comprising an anchor mounted pivotally in the balance bridge. Technological background
[0002] In most mechanical watches, the energy needed to rotate the hands (e.g., minute and hour indicator hands) is stored in a barrel and then released by a balance-spring system, which includes a flywheel called a balance wheel, associated with a spring in the form of a spirally wound ribbon, called a balance spring.
[0003] At one internal end, the spiral is fixed to a shaft that is rotating with the balance wheel; at one external end, the spiral is fixed to a stud mounted on a stud holder which is itself fixed to a bridge (or cock).
[0004] The balance wheel's rotation is maintained—and its oscillations counted—by an escapement mechanism comprising an anchor with a low-amplitude oscillating motion, equipped with two or three pallets that engage the teeth of an escape wheel. Thus engaged, the escape wheel is subjected to a step-by-step rotational movement whose frequency is determined by the anchor's oscillation frequency, itself synchronized with the balance wheel's oscillation frequency.
[0005] With a traditional escapement mechanism, the oscillation frequency is approximately 4 Hz, or about 28,800 vibrations per hour (A / h). One objective of skilled watchmakers is to ensure the isochronism and regularity of the oscillations (or constant rate) of the balance wheel and hairspring.
[0006] The anchor of the escapement mechanism is arranged to provide the mechanical link between the balance wheel and the escape wheel. Thus, the The anchor's placement is important to ensure proper cooperation with the other two components.
[0007] Generally, the anchor consists of a single-piece body comprising a fork that engages with an ellipse of the balance wheel and at least two arms, often each fitted with a pallet, that engage with the escapement mechanism. The anchor body is mounted on a stem with a pivot at each end. During assembly, the pivots are inserted into bearings arranged in bridges or the mainplate.
[0008] Today, the balance spring can be replaced by a flexible guide as the spring element to form a virtual pivot. Flexible guides with a virtual pivot significantly improve watch resonators. The simplest are crossed-leaf pivots, composed of two straight-leaf guide devices that intersect. These two leaves can be either three-dimensional in two different planes or two-dimensional in the same plane, in which case they are essentially welded at their point of intersection. However, there are also uncrossed-leaf guides of the RCC (Remote Center Compliance) type, which have straight leaves that do not intersect. Such a resonator is described in documents EP14199039 and EP16155039.
[0009] However, with such flexible guidance, the balance wheel has a much lower amplitude, the angle of rotation being about twenty degrees, whereas with a balance spring the angle of rotation is 330°, and the balance wheel oscillates with a frequency much higher than that of a balance wheel mounted on a balance spring.
[0010] Thus, new configurations of escapement mechanisms have been invented to be able to work with a flexible-guided regulating organ.
[0011] In most mechanical movements, the escape wheel stem, the pallet fork stem, and the balance wheel arbor are in the same plane. Viewed from above, the position of these three axes forms a straight line. We're talking about online time tracking. However, this setup is quite cumbersome.
[0012] In certain watch movement configurations, the positions of the three axes form a bend. In other words, the escapement wheel, the pallet fork, and the balance wheel are not aligned, but are arranged in a triangular fashion, each at the apex of the same triangle. Such an arrangement reduces the overall size of the watch movement.
[0013] Generally, the pallet fork and the pallets are positioned at the same level within the movement. Furthermore, because the pallet fork interacts with the balance wheel's ellipse and the pallets with the teeth of the escape wheel, the pallet fork and pallets must be spaced far apart to prevent collisions between the ellipse and the escape wheel teeth. This is why an in-line arrangement is typically used.
[0014] Thus, on the one hand, the relative position, particularly the center-to-center distance, between the anchor and the escape wheel must be precisely defined. On the other hand, the relative position, particularly the center-to-center distance, between the anchor and the balance wheel must also be precisely defined.
[0015] In addition, with a state-of-the-art spiral balance wheel, the anchor is in principle mounted between the mainplate and an anchor bridge positioned below the balance wheel, because the latter must be able to rotate above the anchor, due to its dimensions and high angle of rotation.
[0016] Thus, the anchor stem is short, making it more difficult to vertically separate the fork from the pallet arms, particularly to avoid the risk of collision between the fork and the escape wheel in an angled assembly.
[0017] Furthermore, it is more difficult to achieve optimal cooperation between the anchor and the balance wheel ellipse with an anchor bridge, because its assembly does not guarantee a precise center distance with the balance wheel. Summary of the invention
[0018] One aim of the present invention is to provide a movement comprising a new type of escapement mechanism, which avoids the aforementioned defects, in particular the impossibility of simultaneously managing the anchor-balance wheel center distance and the anchor-escapement wheel center distance, which would imply poor cooperation between the anchor and the balance wheel.
[0019] To this end, the invention relates to a clockwork movement, in particular for a watch, the clockwork movement comprising a mainplate, a balance wheel, a balance bridge, a flexible guide, the balance wheel being suspended by the flexible guide so as to be able to oscillate around a virtual axis between the mainplate and the balance bridge, the clockwork movement comprising an escapement mechanism having an anchor and an escape wheel, the anchor cooperating on the one hand with the balance wheel, and on the other hand with the escape wheel, the anchor having a rod mounted pivotally in the clockwork movement, the rod having a first pivot arranged at a first end of the rod, and a second pivot arranged at a second end of the rod, the first pivot being mounted pivotally in the balance bridge.
[0020] The invention is remarkable in that the balance wheel, the escapement wheel and the anchor are arranged so that the center of the escapement wheel, the balance shaft and the anchor rod form a bend having an angle of less than 90°, preferably less than 80°, or even less than 60°, when viewed from above.
[0021] Thus, the stem extends above the balance wheel, and can therefore be longer, so that the fork and pallet arms can be separated more vertically on two different levels, in particular to avoid the risk of collision between the fork and the escape wheel.
[0022] Furthermore, the distance between the first pivot of the anchor stem and the axis of rotation of the balance wheel is arranged at a predetermined distance from one another. on the other hand, to promote good cooperation between the fork and the ellipse of the pendulum.
[0023] Indeed, since the angle of rotation of the balance wheel with a flexible guide is smaller, the stem can extend above the balance wheel.
[0024] According to a particular embodiment of the invention, the second pivot is mounted pivotally in the plate.
[0025] According to a particular embodiment of the invention, the clock movement comprises an escapement bridge, the escape wheel being pivotally mounted in the plate on one side, and in the escapement bridge on the other.
[0026] According to a particular embodiment of the invention, the anchor comprises a fork intended to cooperate with an ellipse of the balance wheel, an entry arm and an exit arm each carrying a pallet intended to cooperate with the escapement wheel.
[0027] According to a particular embodiment of the invention, the balance bridge comprises a first bearing for the balance wheel and a second bearing for the anchor, the distance between the center of the first bearing and the center of the second bearing being predetermined to allow optimal cooperation between the fork of the anchor and the ellipse of the balance wheel.
[0028] According to a particular embodiment of the invention, the plate includes a third bearing for the balance wheel, a fourth bearing for the anchor rod, and a fifth bearing for the escapement wheel, the distance between the center of the fourth bearing and the center of the fifth bearing being predetermined to allow optimal cooperation between the arms of the anchor and the escapement wheel.
[0029] According to a particular embodiment of the invention, the escapement bridge includes a sixth bearing for a pivot of the escapement wheel.
[0030] According to a particular embodiment of the invention, the anchor is arranged on the stem in two separate parts, so that the fork is arranged on a first level and the arms are arranged on a second level, the two levels being separated along the axis of the stem by a non-zero distance allowing the fork to move at least partly above the escapement wheel.
[0031] According to a particular embodiment of the invention, the non-zero distance is between one quarter and three quarters of the length of the rod. Brief description of the figures
[0032] Other features and advantages of the invention will become more apparent upon reading the following description of a particular embodiment of the invention, given by way of simple illustrative and non-limiting example, and the accompanying figures, among which: - Figure 1 schematically represents a top view of a clockwork module comprising a regulating organ and an escapement mechanism, - Figure 2 schematically represents a side view of the clockwork module of Figure 1, and - Figure 3 schematically represents a cross-sectional view of a clockwork movement comprising the clockwork module of figures 1 and 2. Detailed description of the invention
[0033] In figures 1 and 2, the clock module 10 includes an escapement mechanism 50 associated with a regulating organ 60.
[0034] The regulating organ 60 comprises a balance wheel 35, and a flexible guide 32 imparting a rotary motion to the balance wheel 35, while the The escapement mechanism 50 includes an escapement mobile 30, as well as an anchor 21.
[0035] The balance wheel 35 has a bone-like shape with a longitudinal portion 36 and a lateral portion 37 in the form of an arc of a circle at each end of the longitudinal portion 36. The balance wheel 35 further includes stops concentric to the virtual axis of rotation mounted in the middle of the longitudinal portion 36 and adjustment screws 39 for the inertia of the balance wheel arranged in the lateral portions 37.
[0036] The balance wheel 35 is mounted on the flexible guide 32 to enable it to perform a rotary oscillatory motion 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, here two pairs of crossed flexible blades 37, arranged in series, and forming a double pivot to increase the angle of rotation of the rocker 35.
[0038] The anchor 21 is equipped with two arms 11, 12, the ends of which form two pallets cooperating with the teeth 18 of the first escapement wheel 30.
[0039] The arms 11, 12 of the anchor 21 cooperate with the escapement wheel 30, and interact alternately with the teeth 18 of the escapement wheel 30 to regulate the rate.
[0040] The anchor 21 also includes a longitudinal part 14 extending laterally, and is provided with a fork 22 at its end to cooperate with an ellipse 23 of a balance 35.
[0041] The anchor 21 comprises a stem 5 and is arranged in two parts. The fork 22 is arranged on a first level of the stem 5, while the arms 11 and 12 are arranged on a second level of the stem 5.
[0042] Thus, the two levels are separated along the axis of rod 5 by a predefined non-zero distance. Preferably, the distance is between one-quarter and three-quarters of the length of rod 5.
[0043] For example, the first level is arranged substantially at a lower end of the stem 5, while the second level is arranged substantially in the middle of the stem.
[0044] The escapement mechanism 50 further comprises a second clockwork mechanism, the second clockwork mechanism 20 meshing with the first escapement mechanism 30. The second clockwork mechanism 20 is, for example, a seconds wheel. The teeth 14 of the second clockwork wheel 20 mesh with a pinion 3 of the first escapement wheel 30.
[0045] The balance wheel 35 includes an ellipse 23 extending below the balance wheel 35 to cooperate with the fork 22 of the anchor 21. The ellipse 23 is mounted integrally with the balance wheel 35.
[0046] The center of the balance wheel 35, the escapement mechanism 30, and the anchor 21 are arranged on a line forming a bend. Unlike classic escapement mechanisms, where this line is essentially straight, and where the anchor is arranged on this line between the balance wheel and the escape wheel.
[0047] Thus, the balance wheel 35, the escapement mobile 30, and the anchor 21 are each arranged at the apex of a triangle.
[0048] The elbow has an angle of less than 90°, preferably less than 80°, or even less than 60°. Thus, the balance wheel 35, the escapement mobile 30 and the anchor 21 are arranged in a compact manner.
[0049] In figure 3, the clock module of figures 1 and 2 is arranged in a clock movement 1, specifically for a watch.
[0050] In addition to the clock module 10, the clock movement 1 includes a plate 2 and bridges to support the components of the clock module 10.
[0051] In particular, the clockwork mechanism 1 includes a balance bridge 4 arranged above the balance wheel 4. Thus, the balance wheel 4 oscillates between the plate 2 and the balance bridge 4. The balance bridge 4 includes, for example, an upper stop to hold the balance wheel 35 vertically.
[0052] The clockwork movement 1 also includes an escapement bridge 6 to maintain the axis of the escapement mobile 30 in pivoting position.
[0053] The escapement mobile 30 is mounted in pivot between the plate 2 and the escapement bridge 6.
[0054] The rod 5 includes a first pivot 8 arranged at a first end of the rod 5, and a second pivot 7 arranged at a second end of the rod 5.
[0055] According to the invention, the first pivot 8 is mounted in the balance bridge 4, and preferably, the second pivot 7 is mounted in the plate 2. Thus, the anchor 21 is mounted pivotally between the balance bridge 4 and the plate 2. And the stem 5 extends beyond the balance wheel 35.
[0056] To this end, the balance bridge 6 includes a first bearing 13 for the balance wheel 37, which acts as a stop in case of shock, and is concentric with the 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 optimal cooperation between the fork 22 of the anchor 21 and the ellipse 23 of the balance wheel 6.
[0057] The plate 2 includes a third bearing 16 for the balance wheel, a fourth bearing 17 for the anchor rod 5 21, and a fifth bearing 9 for the escapement wheel 30. The distance D2 between the center of the fourth bearing 17 and the center of the fifth bearing 19 is predetermined to allow optimal cooperation between the arms 11, 12 of the anchor 21 and the escapement wheel 30.
[0058] The escapement bridge 6 includes a sixth bearing 24 for a pivot of the escapement mobile 30.
[0059] Thanks to this arrangement of the anchor 21, the cooperation between the arms 11 and 12 of the anchor 21 and the escape wheel 30 on the one hand, and the cooperation between the fork 22 and the ellipse 23 on the other, is better ensured. Indeed, the stem 5 is not at risk of being too inclined relative to the plate 2.
[0060] Indeed, as the anchor 21 and the balance wheel 35 are arranged between the plate 2 and the balance bridge 4, the distance D1 of the center distance defined between the first pivot 8 of the balance wheel 35 and that of the anchor 21 on the balance bridge 4 is constant, and is not likely to vary during assembly.
[0061] Similarly, the distance D2 of the center distance defined between the first pivot 8 of the anchor and the pivot of the escapement mobile 30 on the plate 2 is constant, and does not vary during assembly.
[0062] Naturally, the invention is not limited to the embodiments described with reference to the figures, and variants could be envisaged without departing from the scope of the invention.
Claims
DEMANDS 1. Clockwork movement (1), particularly for a watch, the clockwork movement (1) comprising a mainplate (2), a balance wheel (35), a balance bridge (4), a flexible guide, the balance wheel (35) being suspended by the flexible guide so as to be able to oscillate about a virtual axis between the mainplate (2) and the balance bridge (4), the clockwork movement (1) comprising an escapement mechanism having an anchor (21) and an escape wheel (30), the anchor (21) cooperating on the one hand with the balance wheel (35), and on the other hand with the escape wheel (30), the anchor (21) having a stem (5) pivotally mounted in the clockwork movement (1), the stem (5) having a first pivot (8) arranged at a first end of the stem (5), and a second pivot (7) arranged at a second end of the stem (5), the first pivot (8) being pivotally mounted in the balance bridge (4), characterized in that the balance (4),The escapement wheel (35) and the anchor (21) are arranged so that the center of the escapement wheel (35), the center of the balance wheel (35) and the stem (5) of the anchor (21) form a bend having an angle of less than 90°, preferably less than 80°, or even less than 60°, viewed from above.
2. Clock movement according to claim 1, characterized in that the second pivot (7) of the rod (5) is pivotally mounted in the plate (2).
3. Clock movement according to claim 1 or 2, characterized in that it comprises an escapement bridge (6), the escape wheel (30) being pivotally mounted in the plate (2) on the one hand, and in the escapement bridge (6) on the other hand.
4. A clockwork movement according to any one of the preceding claims, characterized in that the anchor (21) comprises a fork (22) intended to cooperate with an ellipse (23) of the balance wheel (35), an input arm (11) and an output arm (12) each carrying a pallet intended to cooperate with the escapement mechanism (30).
5. A clockwork movement according to any one of the preceding claims, characterized in that the balance bridge (6) comprises a first bearing (13), substantially concentric to the virtual axis, for the balance wheel (38), 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) being predetermined to allow optimal cooperation between the fork (22) of the anchor (21) and the ellipse (23) of the balance wheel (6).
6. A clockwork movement according to any one of the preceding claims, characterized in that the plate (2) includes a third bearing (16) for the balance wheel, a fourth bearing (18) for the anchor rod (5) (21), and a fifth bearing (19) for the escapement wheel (30), the distance (D2) between the center of the fourth bearing (18) and the center of the fifth bearing (19) being predetermined to allow optimal cooperation between the arms (11, 12) of the anchor (21) and the escapement wheel (30).
7. Clock movement according to any one of the preceding claims, characterized in that the escape bridge (6) includes a sixth bearing (24) for a pivot of the escape wheel (30).
8. A clock movement according to any one of the preceding claims, characterized in that the anchor (21) is arranged on the stem (5) in two separate parts, so that the fork (22) is arranged on a first level and the arms (11, 12) are arranged on a second level, the two levels being separated along the axis of the stem (5) by a non-zero distance allowing the fork (22) to move at least partly above the escapement wheel (30).
9. Clock movement according to claim 8, characterized in that the non-zero distance is between one quarter and three quarters of the length of the rod (5).