Clock escapement

Abstract

Escape wheel (1; 1') comprising at least one escape tooth (10; 10'), at least one of the escape teeth comprising a transmission surface (11; 11') which comprises a first proximal contact surface (11a; 11a') and a second distal contact surface (11b; 11b') intended to come into contact with an escape blocker (2), the first proximal contact surface (11a; 11a') being dedicated exclusively to the mechanical transmission of torque from the escape wheel to the blocker and being arranged to act by linear contact with the blocker during the mechanical transmission of torque from the escape wheel to the blocker, the second distal contact surface being configured to come into contact with a resting surface (21b, 22b) of said blocker (2), the resting surface (21b, 22b) being concave.

Description

[0001] The invention relates to a watch escapement wheel. It also relates to a watch escapement system comprising such a wheel. It further relates to a watch movement comprising such a wheel or such an escapement system. It also relates to a timepiece, in particular a wristwatch, comprising such a wheel, system, or movement. Finally, it relates to a method of operating such a system, movement, or component.

[0002] Patent application WO2013182243 discloses an escapement comprising an escape wheel designed to cooperate with a locking mechanism made of two separate moving parts. During the impulse phases of the escapement system, the escape wheel and the locking moving part, which is in contact with the escape wheel, rotate in opposite directions. The drive of the locking mechanism by the escape wheel is said to be tangential. This method of operating an escapement system is advantageous because it requires little energy, as friction is low between the escape wheel and the two moving parts of the locking mechanism. Each tooth of the escape wheel comprises a transmission surface that includes a distal contact surface for engaging a locking moving part, and a proximal contact surface for engaging an impulse surface of the locking moving part. Both the proximal and impulse surfaces are planar.Thus, during an impulse phase of the escapement system, a transmission surface of a tooth of the escape wheel and a surface of the locking lug are at least partially in planar contact. Such a configuration is not optimal.

[0003] The aim of the invention is to provide an escape wheel and an escapement system that further improves upon prior art escapement systems. In particular, the invention proposes a simple escape wheel that minimizes energy losses through an optimized transmission surface for one escape wheel tooth.

[0004] According to a first aspect of the invention, an escape wheel according to the invention is defined by claim 1.

[0005] Different embodiments of the escape wheel are defined by dependent claims 2 to 9.

[0006] A watch escapement system according to the invention is defined by claim 10.

[0007] Different embodiments of the watch escapement system are defined by dependent claims 11 and 12.

[0008] A watch movement according to the invention is defined by claim 13.

[0009] A timepiece according to the invention is defined by claim 14.

[0010] A method of operation according to the invention is defined by claim 15.

[0011] According to a second aspect, the invention is defined by the following propositions. 1. Escape wheel (1; 1') comprising at least one escape tooth (10; 10'), at least one of the escape teeth comprising a transmission surface (11; 11') which comprises a first proximal contact surface (11a; 11a') and a second distal contact surface (11b; 11b') intended to come into contact with an escape blocker (2), the first proximal contact surface (11a; 11a') being dedicated exclusively to the mechanical transmission of torque from the escape wheel to the blocker and being arranged to act by linear contact with the blocker during the mechanical transmission of torque from the escape wheel to the blocker. 2. Escape wheel according to proposition 1, characterized in that the second distal contact surface is configured to come into contact with a pulse surface (21a, 22a) of a blocker (2) and to come into contact with a rest surface (21b, 22b) of said blocker (2). 3.4. Escape wheel according to one of propositions 1 and 2, characterized in that the second distal contact surface (11b) is convex and the first proximal contact surface (11a) is convex, the second distal surface and the first proximal surface being connected by at least one edge or at least one intermediate surface (11c) that is planar or concave. 5. Escape wheel according to proposition 3, characterized in that the intermediate surface comprises a portion of a third cylinder of revolution (R1c) or substantially comprises a portion of a third cylinder of revolution (R1c). 6. Escape wheel according to proposition 3 or 4, characterized in that the first proximal contact surface comprises a portion of a first cylinder of revolution (R1a) or substantially comprises a portion of a first cylinder of revolution (R1a) or comprises a portion of a cylinder whose directrix is ​​an involute of a circle. 7.Escape wheel according to any one of propositions 1 to 5, characterized in that the second distal contact surface comprises a portion of a second cylinder of revolution (R1b) or substantially comprises a portion of a second cylinder of revolution (R1b). 7. Escape wheel according to propositions 5 and 6, characterized in that the ratio of the radius of the first cylinder to the radius of the second cylinder is between 7 and 11, in particular between 8 and 10, preferably equal to 9 or substantially equal to 9. 8. Escape wheel according to any one of propositions 1 and 2, characterized in that the first proximal contact surface (11a') is formed in continuity with the second distal contact surface (11b'). 9.Escape wheel according to any one of propositions 1, 2, and 8, characterized in that the first proximal contact surface (11a') comprises at least one concave portion (113a'), in particular in that the first proximal contact surface (11a') comprises at least one first flat or substantially flat portion (111a', 112a'). 10. Watch escapement system (100), the system comprising an escape wheel according to any one of propositions 1 to 9. 11. Watch escapement system according to proposition 10, characterized in that the system is of the tangential type and / or in that the system comprises a stop (2) including two moving parts (21, 22) configured to mesh with each other. 12.A clockwork escapement system according to one of propositions 10 and 11, characterized in that the system comprises two moving parts (21, 22), each having an impulse surface (21a, 22a) including a portion of a cylinder whose directrix is ​​an involute of a circle, and / or each having a concave rest surface (21b, 22b), and / or in that the stopper and the escape wheel are arranged such that a pressure angle (α) formed by: a perpendicular (PC) to a line of centers (LC) of the escape wheel and the stopper, and a line of meshing (L1) at the point of contact between the convex proximal contact surface (11a) and an impulse surface (21a, 22a) of the stopper, is between 10° and 40°, inclusive, or even between 15° and 30°, 15° and 30° inclusive, for example, is equal to or substantially equal to 20°. 13.14. Timepiece (300), in particular wristwatch, comprising a timepiece (200) according to proposal 13 and / or a system according to one of proposals 10 to 12 and / or an escapement wheel according to one of proposals 1 to 9. 15.A method for operating an escapement system (100) comprising an escape wheel (1) and an escape wheel blocker (2), in particular a system according to any one of Propositions 10 to 12, the method comprising: a first step of applying a first mechanical action of a first proximal contact surface (11a; 11a') of an escape wheel tooth (10; 10') on an impulse surface of the blocker (21a, 22a), in particular a first step of applying a first mechanical action of a first convex proximal contact surface (11a) of an escape wheel tooth (10) on an impulse surface of the blocker (21a, 22a); and a second step of applying a second mechanical action of a convex distal contact surface (11b; 11b') of the tooth on the impulse surface of the blocker.

[0012] The attached figures represent, as examples, two ways of making a timepiece. There figure 1is a view of an embodiment of a timepiece comprising a first embodiment of an escape wheel, the escapement of the timepiece being in a first rest position. figure 2 is a detailed view of the figure 1 at the point of contact between a locking mechanism and an exhaust wheel. The figure 3 This is a view of the timepiece's embodiment, with the timepiece's escapement in the first impulse stage. figure 4 is a detailed view of the figure 3 at the point of contact between a locking mechanism and an exhaust wheel. The figure 5 This is a detailed view of the lock-exhaust wheel contact at a transition instant between the first pulse stage and a second pulse stage. figure 6 This is a view of the timepiece's embodiment, with the timepiece's escapement located in the second impulse stage. figures 7 and 8are detailed views of the figure 6 at the exhaust wheel lock contact point. The figure 9 This is a view of the timepiece's embodiment, with the timepiece's escapement in a second rest position. Figure 10 This is a detailed view of one embodiment of a tooth on an escape wheel. figure 11 is a view of a second embodiment of the escape wheel. The figure 12 is a view of a variant of the second embodiment of the escape wheel.

[0013] An embodiment of a 300 timepiece is described below with reference to figures 1 to 10A timepiece is, for example, a watch or a wristwatch. A timepiece may include a mechanical watch movement, particularly an automatic one. A timepiece may also include a complete watch assembly, such as a watch case designed to house the movement.

[0014] The watch movement includes an escapement system 100 interposed between an oscillator 3 and a finishing gear linking an energy accumulator, such as a barrel, to the escapement system.

[0015] The oscillator 3, or resonator, is, for example, of the balance-spring type. The oscillator, particularly the balance wheel, comprises, for example, a plate 32 and a pin 31 or a finger 31. The pin is, for example, designed to cooperate with a fork 21c formed on the stop in order to transmit impulses to the oscillator. The oscillator, particularly the balance wheel, is, for example, pivoted about an axis A on a frame of the movement.

[0016] The exhaust system is preferably of the tangential type.

[0017] The exhaust system includes a blocker 2 and an exhaust wheel 1.

[0018] Preferably, the locking device 2 comprises a first moving part 21 and a second moving part 22. For example, the first moving part is pivoted about an axis B on the motion frame. For example, the second moving part is pivoted about an axis C on the motion frame. Axes B and C are preferably distinct and parallel or substantially parallel to each other. Furthermore, axes B and C are preferably parallel or substantially parallel to axis A.

[0019] Advantageously, the first moving part 21 comprises a first set of teeth 21d and the second moving part 22 comprises a second set of teeth 22d, the first and second sets of teeth being arranged to mesh with each other. Preferably, the first and second sets of teeth are arranged such that the teeth have conjugate profiles that theoretically roll against each other without slipping. The locking mechanism 2 therefore comprises two moving parts 21, 22 configured to mesh with each other.

[0020] Each of the first and second moving parts includes a pulse surface 21a, 22a and a rest surface 21b, 22b.

[0021] Preferably, the impulse surface 21a of the first mobile 21 includes a portion of a cylinder whose directrix is ​​an involute of a circle or a circle and / or whose generatrices are parallel or substantially parallel to the axis B.

[0022] Preferably, the impulse surface 22a of the second mobile 22 includes a portion of a cylinder whose directrix is ​​an involute of a circle or a circle and / or whose generatrices are parallel or substantially parallel to the axis C.

[0023] By "cylinder", we mean, throughout this document, a geometric surface formed by a set of generating lines parallel to each other and resting on or intersecting a directrix curve.

[0024] The impulse surfaces preferably extend substantially radially relative to the axes of rotation of the moving parts.

[0025] The impulse surfaces are designed to receive oscillator drive forces applied by the teeth of the escape wheel driven by the energy accumulator via the finishing gear.

[0026] Preferably, the resting surface 21b of the first mobile 21 includes a concave portion, as shown in the figure 2 .

[0027] Preferably, the resting surface 22b of the second mobile 22 includes a concave portion.

[0028] The resting surfaces preferably extend substantially orthoradially relative to the axes of rotation of the moving parts.

[0029] The resting surfaces are designed to lock the escape wheel by acting on one of its teeth.

[0030] Preferably, such a resting or locking surface for the blocker is concave to provide protection in case of impact or rebound of the exhaust wheel. Even more preferably, such a locking surface 21b, 22b for the blocker 2 is formed by two flanks 210b, 220b, 211b, 221b configured as concave and forming an angle between 120° and 170°.

[0031] The oscillator drive fork 21c is for example made on the first moving part 21.

[0032] The escape wheel is mounted to rotate freely on the frame around an axis D. The axis D is, for example, parallel to the axes A, B and C.

[0033] The escape wheel may include one or more teeth 10, in particular two, four, five or six teeth or, for example, three teeth as in the embodiment shown.

[0034] At least one of the escape teeth 10 includes a transmission surface 11 which includes a first proximal contact surface 11a and a second distal contact surface 11b intended to come into contact with the blocker, the first proximal contact surface 11a being dedicated exclusively to the mechanical transmission of torque from the escape wheel to the blocker and being arranged to act by point contact with the blocker during the mechanical transmission of torque from the escape wheel to the blocker.

[0035] By "point contact between surfaces," we mean that there is a point contact between these surfaces in one or more planes perpendicular to axis D. Consequently, considering the thickness of the escape wheel and the stopper, there is in fact a linear contact between the wheel and the stopper; that is, there is contact along a line, or substantially along a line, between the wheel and the stopper. This linear contact is preferably rectilinear. It can, however, be curvilinear. Thus, the term "point contact" does not have a temporal meaning in this document.

[0036] Advantageously, the first proximal contact surface 11a extends over at least 20%, or even at least 30%, or even at least 40%, of the extent of the transmission surface 11. This extent is advantageously measured in a plane perpendicular to the axis D.

[0037] The contact surfaces 11a and 11b are designed to come into contact with the blocker; that is, all points on these surfaces are capable of making contact with the blocker. The proximal and distal surfaces constitute all or part of the transmission surface 11.

[0038] The transmission surface 11 extends from a first contact point P1 between the first proximal contact surface 11a and a pulse surface of the blocker initiating a pulse phase of the escape device to a second contact point P2 between the second distal contact surface 11b and said pulse surface of the blocker closing said pulse phase of the escape device.

[0039] By "pulse phase" is meant a phase in which the escape wheel transmits a driving torque to the oscillator 3 or resonator by means of a contact drive of the blocker 2. During a pulse phase, a transmission surface 11 of the wheel is thus in contact with a pulse surface 21a, 21b of the blocker 2.

[0040] The transmission surface 11 constitutes all or part of a tooth surface of the escape wheel extending radially or substantially radially with respect to axis D. "Distal surface" and "proximal surface" are understood to be surfaces arranged such that the distal surface is farther from axis D than the proximal surface. Preferably, the distance from axis D of any point on the distal surface is greater than the distance from axis D of any point on the proximal surface.

[0041] The proximal surface is optimized and is exclusively dedicated, during the impulse phases of the escapement system, to the mechanical transmission of torque from the escape wheel to the blocker. More specifically, the proximal surface is designed to cooperate exclusively, through point or linear contact, with impulse surfaces 21a, 22a of the blocker. Advantageously, the distal surface is also designed to cooperate with impulse surfaces 21a, 22a of the blocker. Furthermore, the distal surface is also designed to cooperate with blocking or resting surfaces 21b, 22b of the blocker during the rest positions of the escapement system. In such positions, a tooth 10 of the escape wheel bears against a predefined blocking surface 21b, 22b of the blocker 2.

[0042] Thus, the profile or transmission surface 11 of tooth 10 of the exhaust wheel 1 is designed to allow for the coexistence of a first function of torque transmission from the exhaust wheel to the locking mechanism and a second function of locking the exhaust wheel, while optimizing the first torque transmission function by minimizing, in particular as much as possible, the sliding contact between the exhaust wheel and the locking mechanism. The energy transmission from the exhaust wheel to the locking mechanism is thereby improved.

[0043] According to a first embodiment, the transmission surface 11 comprises a first convex proximal contact surface 11a and a second convex distal contact surface 11b, the proximal and distal surfaces being connected by at least one edge or at least one intermediate surface 11c.

[0044] According to a particular variant of the first embodiment as illustrated by the figures 1 to 10The proximal and distal surfaces are connected by a concave intermediate surface 11c. Alternatively, the intermediate surface 11c could be flat. Preferably, the intermediate surface 11c is not intended to come into contact with the impulse surfaces 21a, 22a of the blocker.

[0045] A "convex surface" refers to a tooth surface that forms a raised boss oriented in one direction, such as a projecting boss. A "concave surface" refers to a tooth surface that forms a raised boss oriented in a second direction, such as a concave boss.

[0046] In other words, according to the first embodiment, at least one of the escape teeth 10 comprises a proximal contact surface 11a and a distal contact surface 11b having a radius of curvature of the same sign, the distal and proximal surfaces being connected by at least one edge or at least one intermediate surface 11c: of zero radius of curvature; or whose sign is opposite to that of the radius of curvature of the proximal contact surfaces 11a and distal contact surfaces 11b; or planar; or whose radius of curvature is greater than 0.02 mm.

[0047] By "edge", we mean a line of intersection between two continuous surfaces.

[0048] The proximal contact surface is advantageously configured to come exclusively into contact with the impulse surface 21a, 22a of the blocker 2.

[0049] Advantageously, this proximal contact surface can include a portion of a first cylinder of revolution R1a parallel to the axis D as shown in the Figure 10 or may substantially include a portion of a first cylinder of revolution R1a parallel to the axis D or may include a portion of a cylinder whose directrix is ​​an involute of a circle and whose generatrices are parallel to the axis D.

[0050] The distal surface 11b of the profile 11 or of the transmission surface 11 of the tooth 10 of the escape wheel 1 may, due to its convexity, have a geometry complementary to that of the blocking surface 21b, 22b of the blocker 2. This complementarity is not necessarily strict. Indeed, the complementarity may simply result from the fact that the distal surface is convex and that the resting surface(s) are concave. The distal surface 11b of the profile 1, in the resting positions of the escapement system, is preferentially shaped so as to be positioned tangent to the blocking surface 21b, 22b of the blocker, in particular tangent to the two flanks 210b, 220b and 211b, 221b forming a concave blocking surface 21b, 22b of the blocker 2.

[0051] The distal contact surface is advantageously configured to come into contact with the impulse surfaces 21a, 22a of the blocker 2 and to come into contact with the rest surfaces 21b, 22b of the blocker 2.

[0052] Advantageously, the distal contact surface comprises a portion of a second cylinder of revolution R1b parallel to the axis D as shown in the Figure 10 or substantially includes a portion of a second cylinder of revolution R1b parallel to the axis D.

[0053] The ratio of the radius of the first cylinder to the radius of the second cylinder may be between 7 and 11, 7 and 9 inclusive, in particular between 8 and 10, 8 and 10 inclusive, preferably equal to 9 or substantially equal to 9.

[0054] The intermediate surface may, in turn, include a portion of a third cylinder of revolution R1c parallel to the axis D as shown in the Figure 10or substantially include a portion of a third cylinder of revolution R1c parallel to the axis D.

[0055] According to a second embodiment, the escape wheel 1' is partially represented on the Figures 11 and 12 It comprises a first proximal contact surface 11a' formed in continuity with a second distal contact surface 11b', or vice versa, so as to form a transmission surface 11' without an intermediate surface. In this embodiment, the proximal and distal surfaces constitute the transmission surface 11. Advantageously, such an embodiment allows for torque transmission without discontinuity of contact between the transmission surface of the escape wheel and the impulse surface of the locking mechanism. The direction of the planes tangent to the transmission surface therefore evolves continuously and without interruption along the transmission surface.

[0056] On the Figures 11 and 12, the elements having the same functions as those already represented in the previous figures bear the same references to which a " " has been added.

[0057] According to a particular variant of the second embodiment as illustrated by the figure 11 The proximal contact surface 11a' may include at least a first flat or substantially flat portion 111a', 112a' and at least a second concave portion 113a'. The distal contact surface 11b' is, however, convex.

[0058] Regardless of the embodiment considered, the individual teeth of the escape wheel may be identical. Alternatively, only one or some teeth of the escape wheel may be shaped as described above.

[0059] As depicted in an exaggerated manner on the figure 12Microscopic or nanoscopic discontinuities can be formed on the proximal and distal surfaces of the transmission surface, notably for the purpose of, for example, accommodating a lubricant. This does not change the planar, convex, or concave nature of these surfaces at the macroscopic scale.

[0060] An execution method of an operating process of an escapement system as previously mentioned, or of a clock movement as previously mentioned, or of a timepiece as previously mentioned, is described below with reference to figures 1 to 10 .

[0061] The oscillator and escapement system are initially assumed to be in the position of Figures 1 And 2 The oscillator pin is in a position of limited contact with the first locking mechanism. The oscillator rotates counterclockwise relative to axis A on the figure 1The first locking mobile is in the position of locking the escape wheel, the distal surface 11b being in contact with the resting surface 21b. The distal surface 11b of the profile 11 of the tooth 10 is here tangent to the flanks 210b, 211b of the locking surface 21b of said mobile 21.

[0062] The oscillator rotates counterclockwise relative to axis A on the figure 1 , via the pin 31 and the fork 21c, it drives the first mobile in a clockwise direction until it reaches the position shown on the figures 3 And 4 .

[0063] We then reach the positions of the oscillator and the escapement system illustrated by the figures 3 And 4 . These figures 3 And 4illustrate the beginning of the first stage of a drive phase, with the proximal surface 11a of the profile 11 of the tooth 10 of the wheel 1 initiating its cooperation by contact with the drive surface 21a of the first moving part 21 of the blocker 2 at a contact point P1. During this first stage, the proximal surface 11a of the profile 11 of the tooth 10 of the wheel 1 drives the first moving part 21 by cooperating through contact with the drive surface 21a of the first moving part 21. In the case where the proximal surface 11a and the drive surface 21a each have an involute tooth profile, the escape wheel and the first moving part theoretically roll against each other without slipping. During this cooperation by contact of the proximal surface 11a and the impulse surface 21a, the point of contact between the tooth 10 and the impulse surface 21a is located on an interlocking line or pressure line L1 shown on the figure 5Preferably, the pressure angle α formed by the perpendicular PC to the line of centers LC of the escape wheel 1 and the first moving part 21 (or passing through axes B and D) and the meshing line L1 is on the order of 20°. Of course, this angle can be between 10° and 40°. The figure 5 illustrates such a line of engagement L1 at the moment when the first stage of said impulse phase is completed, namely at the moment when the distal surface 11b of the profile 11 comes into contact with the impulse surface 21a of the first mobile 21.

[0064] Thus, the process includes a first step of applying a first mechanical action from the convex proximal contact surface 11a of a tooth 10 of the escape wheel to the impulse surface of the blocker 21a. This first step is a first impulse phase step. The first moving part of the blocker consequently applies a force, in particular a torque, or an impulse to the oscillator.

[0065] The first moving part 21 continues to rotate under the action of the tooth on the impulse surface 21a, thus reaching the positions of the oscillator and the escapement system illustrated by the figures 6 to 8 . These figures 6 to 8 illustrate a second stage of a pulse phase, the escape wheel 1 cooperating by contact with the first moving part 21 of the blocker 2. During this second stage, the distal surface 11b of the tooth profile 10 of the wheel 1 drives the first moving part 21 by cooperating with the pulse surface 21a of the first moving part 21. During the cooperation of surfaces 11b and 21a, the point of contact between the tooth 10 and the pulse surface 21a is located on a meshing line or pressure line L2. Preferably, the pressure angle β formed by the perpendicular PC to the line of centers LC of the escape wheel 1 and the first moving part 21 (or passing through axes B and D) is zero or substantially zero.

[0066] Thus, preferably, the angle γ (represented on the figure 8 (via a virtual extension of line L1 drawn in light gray and dotted) formed by lines L1 and L2 is on the order of the value of angle α. This angle can be between 10° and 40°. figure 8 illustrates such a line of engagement L2 at the moment when the second stage of said impulse phase is about to end while the distal surface 11b is in contact with the impulse surface 21a at a point P2, namely at the moment when the distal surface 11b of the profile 11 is about to cease cooperating with the impulse surface 21a of the mobile 21.

[0067] Thus, the method includes a second step of applying a second mechanical action from the distal contact surface 11b of the tooth to the impulse surface 21a of the blocker. This second step is a second impulse phase step. The first moving part of the blocker consequently applies a force, in particular a torque, or an impulse to the oscillator.

[0068] Preferably, the first step is maintained during a stroke of the blocker whose amplitude is equal to or greater than 30%, or even equal to or greater than 40%, or even equal to or greater than 50%, of the amplitude of the total stroke of the blocker during the impulse phase.

[0069] Preferably, the second step is maintained during a stroke of the blocker whose amplitude is equal to or greater than 30%, or even equal to or greater than 40%, or even equal to or greater than 50%, of the amplitude of the total stroke of the blocker during the impulse phase.

[0070] During the impulse phase of the escapement system, the escape wheel 1 transmits a torque to the blocker 2 so as to cause and maintain the oscillations of the oscillator 3 by means of the fork 21c of the blocker mobile 21 cooperating with the pin 31 of the plate 32 of the resonator 3. During the impulse phase of the escapement system, the escape wheel 1 transmits a driving torque to the oscillator 3 or resonator by means of a contact drive of the blocker 2.

[0071] At the end of the impulse phase, the tooth of the escape wheel leaves the impulse surface 21a (under the effect of the torque produced by the driving element) and comes to rest against the rest surface 22b of the second moving part 22 of the locking mechanism as shown in the figure 9 .

[0072] Thus, interaction steps similar to those described previously can occur between a tooth of the escape wheel and the second moving blocker.

[0073] Thus, the escape wheel 1 can cooperate in the same way with the second mobile 22 of the blocker 2, and in particular with the impulse surface 22a of the second mobile 22 during another impulse phase of the escape system.

[0074] The operation of the escapement system, movement, or timepiece may therefore include iterations of the following cycle: Rest of the escape wheel on the resting surface 21b of the first mobile 21; then Impulse of the escape wheel on the impulse surface 21a of the first mobile 21 comprising: ∘ First impulse stage of the proximal surface 11a of the escape wheel on the impulse surface 21a of the first mobile 21; then ∘ Second impulse stage of the distal surface 11b of the escape wheel on the impulse surface 21a of the first mobile 21; then Rest of the escape wheel on the resting surface 22b of the second mobile 22; then Disengagement of the pin 31 of the plate 32 of the oscillator 3 from the fork 21c of the first mobile 21; then Impulse of the escape wheel on the impulse surface 22a of the second mobile 22 comprising: ∘ First impulse step of the proximal surface 11a of the escape wheel on the impulse surface 22a of the second mobile 22;then ∘ Second impulse stage of the distal surface 11b of the escape wheel on the impulse surface 22a of the second mobile 22; then Disengagement of the pin 31 of the plate 32 of the oscillator 3 from the fork 21c of the first mobile 21. ;

[0075] Preferably, the first proximal surface of the transmission surface of an escape wheel tooth is shaped to generate point or line contact between said escape wheel and a locking lug during an impulse phase of the escape system. Preferably, this point or line contact is maintained throughout the entire first impulse phase or for a portion greater than 50%, or even 70%, or 90% of the first phase (this portion representing the stroke of the locking lug in point or line contact with the wheel over the total stroke of the locking lug during the entire first impulse phase).

[0076] Preferably, the location of the point or line contact moves on the first proximal surface and / or on the impulse surface of the blocker during the first impulse step.

[0077] Preferably, the impulse surfaces of the blocker are also arranged so as to ensure point or line contact between the escape wheel and the blocker, as described above.

[0078] This operation can also be implemented using an escape wheel as described in reference to Figures 11 and 12 .

[0079] The second mobile 22 can therefore cause and maintain the oscillations of the oscillator 3 by means of the first mobile 21, and in particular by means of the teeth 22d cooperating with the teeth 21d of the mobile 21, as taught in patent application WO2013182243.

[0080] Overall, the exhaust wheel and exhaust system function similarly to those disclosed in application WO2013182243.

[0081] However, as previously mentioned, the escape wheel described above is unique in that it features teeth with optimized mechanical transmission surfaces between the escape wheel and a locking mechanism that forms part of the watch escapement. This optimizes the transmission ratio between the moving parts and minimizes friction during escapement operation. Furthermore, the chosen geometries ensure that the torque transmitted from the escape wheel to the oscillator remains as constant as possible throughout the impulse phase.

Claims

1. Escape wheel (1; 1') comprising at least one escape tooth (10; 10'), at least one of the escape teeth comprising a transmission surface (11; 11') which comprises a first proximal contact surface (11a; 11a') and a second distal contact surface (11b; 11b') intended to come into contact with an escape blocker (2), the first proximal contact surface (11a; 11a') being dedicated exclusively to the mechanical transmission of torque from the escape wheel to the blocker and being arranged to act by linear contact with the blocker during the mechanical transmission of torque from the escape wheel to the blocker, the second distal contact surface being configured to come into contact with a resting surface (21b, 22b) of said blocker (2), the resting surface (21b, 22b) being concave.

2. Exhaust wheel according to the preceding claim, characterized in thatthe second distal contact surface is configured to come into contact with a pulse surface (21a, 22a) of a blocker (2).

3. Exhaust wheel according to any one of the preceding claims, characterized in that the second distal contact surface (11b) is convex and the first proximal contact surface (11a) is convex, the second distal surface and the first proximal surface being connected by at least one edge or at least one intermediate surface (11c) which is flat or concave.

4. Exhaust wheel according to the preceding claim, characterized in that the intermediate surface comprises a portion of a third cylinder of revolution (R1c) or substantially comprises a portion of a third cylinder of revolution (R1c).

5. Exhaust wheel according to claim 3 or 4, characterized in thatthe first proximal contact surface includes a portion of a first cylinder of revolution (R1a) or includes substantially a portion of a first cylinder of revolution (R1a) or includes a portion of a cylinder whose directrix is ​​an involute of a circle.

6. Exhaust wheel according to any one of the preceding claims, characterized in that the second distal contact surface comprises a portion of a second cylinder of revolution (R1b) or substantially comprises a portion of a second cylinder of revolution (R1b).

7. Exhaust wheel according to claims 5 and 6, characterized in that the ratio of the radius of the first cylinder to the radius of the second cylinder is between 7 and 11, in particular between 8 and 10, preferably equal to 9 or substantially equal to 9.

8. Exhaust wheel according to one of claims 1 and 2, characterized in thatthe first proximal contact surface (11a') is formed in continuity with the second distal contact surface (11b').

9. Exhaust wheel according to any one of claims 1, 2 and 8, characterized in that the first proximal contact surface (11a') includes at least one concave portion (113a'), in particular in that the first proximal contact surface (11a') includes at least a first flat or substantially flat portion (111a', 112a').

10. Clock escapement system (100), the system comprising an escape wheel according to any one of the preceding claims.

11. Clock escapement system according to the preceding claim, characterized in that the system is of the tangential and / or type in that the system includes a blocker (2) comprising two mobiles (21, 22) configured to mesh with each other.

12. A watch escapement system according to any one of claims 10 and 11, characterized in thatthe system comprises two moving parts (21, 22) each having a pulse surface (21a, 22a) including a portion of a cylinder whose directrix is ​​an involute of a circle and / or each having a concave rest surface (21b, 22b) and / or in that The blocker and the escape wheel are arranged so that a pressure angle (α) formed by: - ​​a perpendicular (PC) to a line of centers (LC) of the escape wheel and the blocker, and - a line of meshing (L1) at the level of a contact between the convex proximal contact surface (11a) and a pulse surface (21a, 22a) of the blocker, is between 10° and 40°, 10° and 40° inclusive, or is between 15° and 30°, 15° and 30° inclusive, for example is equal or substantially equal to 20°.

13. Watch movement (200) comprising a system according to any one of claims 10 to 12 and / or an escape wheel according to any one of claims 1 to 9.

14. Timepiece (300), in particular wristwatch, comprising a timepiece movement (200) according to the preceding claim and / or a system according to any one of claims 10 to 12 and / or an escape wheel according to any one of claims 1 to 9.

15. Method of operating an escapement system (100) comprising an escape wheel (1) and an escape wheel blocker (2), in particular a system according to any one of claims 10 to 12, the method comprising: - a first step of applying a first mechanical action of a first proximal contact surface (11a; 11a') of a tooth (10; 10') of the escape wheel on an impulse surface of the blocker (21a, 22a), in particular a first step of applying a first mechanical action of a first convex proximal contact surface (11a) of a tooth (10) of the escape wheel on an impulse surface of the blocker (21a, 22a); and - a second step of applying a second mechanical action of a convex distal contact surface (11b; 11b') of the tooth on the impulse surface of the blocker.

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