CH715589B1 - Escapement with rubbing rest. - Google Patents

Abstract

The invention relates to a rubbing rest escapement (100) comprising: – an pallet (2), – an escapement wheel (1) comprising: – a hub (3), comprising an axis of rotation around which the hub (3 ) is intended to rotate, – a plurality of arms (10) extending from the hub (3), wherein either the anchor (2) and/or one arm (10) of said plurality of arms comprises: a elastic portion, a rigid portion, intended to interact with the arm (10) respectively with the anchor (2), said elastic portion being arranged to flex during a phase of rest when the arm (10) comes into contact with the anchor ( 2), so as to facilitate starting of said exhaust. The escapement according to the invention is suitable for working with an oscillator having an oscillation amplitude of less than 10°, the lever of the escapement being linked to the oscillator.

Description

Technical area

The present invention relates to a rubbing rest escapement, for example a Graham escapement.

State of the art

[0002] As a general rule, an escapement comprises an escape wheel which cooperates with an oscillator (for example via an anchor), in order to maintain and count its oscillations. In a rubbing rest escapement, the escape wheel is in almost permanent contact with the oscillator or with an anchor linked to this oscillator. It advances only during the short moment of the impulse and that of the fall.

[0003] A rubbing rest escapement also comprises, in addition to the escape wheel, an escapement member linked to the oscillator. In what follows, this organ will be called an anchor. In a rubbing rest escapement, the lever remains constantly in contact with the escapement wheel during the resting or stopping phase, hence the name „rubbing rest“.

[0004] The oscillator can be a pendulum. In the case of a watch, for example a wristwatch, the oscillator is for example a balance-spring system.

[0005] The Graham escapement is a type of substantially recoil-free rubbing resting escapement. It cooperates with an anchor, linked to the oscillator (to the pendulum for example). The anchor comprises two vanes, each vane comprising a plane (or surface) of rest and a plane (or surface) of impulse.

[0006] Other examples of rubbing rest escapements include cylinder, comma, double comma, etc., escapements.

[0007] The Swiss lever escapement is not a rubbing rest escapement. It is a free escapement, as it only comes into contact with the oscillator during the lift angle to perform the release and impulse phases. The rest of the time, the oscillator is free. In addition, its anchor is faster compared to the anchor of a rubbing rest escapement, which oscillates at the same speed as the oscillator.

[0008] Today, the Swiss lever escapement is by far the most widely used. It happens, however, that for certain watches, other types of escapement are chosen.

[0009] One of the particularities of a rubbing rest escapement, in particular a Graham escapement, is linked to the fact that its lever can work on very small angular rotations, for example angular rotations having an amplitude of less than 10°, for example equal to 5° or 6°.

[0010] It is therefore an escapement which is suitable for working with a regulating member having weak oscillations. Such is the case, for example, of a regulating member in one piece, without mechanical connections, with flexible guidance, which replaces the known conventional balance-spring systems.

[0011] A non-limiting example of such a regulating member with low oscillation amplitudes is described in application EP3021174 filed by the applicant.

[0012] However, a rubbing rest escapement has the disadvantage of not being self-starting. In other words, it requires a fairly large impulse to start.

[0013]There is therefore a need for a self-starting rubbing rest escapement, or one in which starting is facilitated compared with known rubbing rest escapements.

Brief summary of the invention

[0014] An object of the present invention is therefore to provide a self-starting rubbing rest escapement, or one in which starting is facilitated compared with known rubbing rest escapements.

[0015] According to the invention, these objects are achieved in particular by means of the rubbing rest escapement according to claim 1, by means of the timepiece mechanism according to claim 11, by means of the timepiece movement according to claim 13 and by means of the watch according to claim 14.

[0016] According to the invention, the rubbing rest escapement comprises: – an anchor, and – an escape wheel comprising: – a hub; an axis of rotation around which the hub is intended to rotate, and - a plurality of arms extending from the hub.

According to the invention, the anchor and/or one arm of the plurality of arms comprises (comprises): an elastic portion, and a rigid portion, intended to interact with the arm respectively with the anchor.

[0018] In this context, an "elastic portion" is a flexible or deformable portion, which returns to its original state after being flexed or deformed.

[0019] In this context, a “rigid portion” is a portion which is not substantially flexible or deformable, and in any case less flexible or deformable than the elastic portion.

[0020]According to the invention, the elastic portion is arranged to flex when an arm of the escapement wheel comes into contact with the lever during a rest phase of the escapement at rest rubbing, so as to facilitate the start of the escapement at rubbing rest.

[0021] Thanks to this bending, the end of the arm of the escape wheel can be released from the anchor more easily compared to known solutions, which allows the escapement to start automatically at rest rubbing or else a start even during a small impulse given to the escapement at rest rubbing: for example, it suffices that the wearer of a wristwatch comprising the escapement according to the invention shakes his wrist slightly so that the escapement according to the invention begins to work.

[0022] In a first embodiment, the anchor is rigid, the arm of the escape wheel comprises an elastic blade and a rigid distal part. In this embodiment, the distal part comprises a protuberance, forming a tooth of the escape wheel intended to interact with the lever. In this embodiment, the blade is arranged to flex during the rest phase upon contact of the corresponding tooth with the anchor, so that the distance between the center of the escape wheel and one end of the tooth is reduced in relation to the same distance in correspondence of the other teeth (and/or in relation to the same distance in correspondence of this tooth before coming into contact with the anchor, that is to say before flex). In other words, the blade is arranged to flex during the rest phase when the corresponding tooth contacts the anchor, so that the radius of the escape wheel in correspondence of this tooth is reduced by with respect to the radius of the escape wheel in correspondence of the other teeth (and/or with respect to the radius of the escape wheel in correspondence of this tooth before coming into contact with the anchor, i.e. say before bending). The tooth thus approaches the center of the escape wheel, and moves away from the pallet, which limits its engagement with the pallet of the pallet and makes it easier to start the escapement after a stop.

[0023] In a second embodiment, the escape wheel is rigid and comprises at least one tooth while the anchor comprises a pallet with a body and a distal or extremal part. In this embodiment, the body of the pallet is arranged to flex during the rest phase upon contact between the distal part and the tooth of the escapement wheel, so that the distance between the center of the wheel escapement and one end of the distal part of the pallet of the anchor increases during bending, so as to facilitate the starting of the escapement. The distance between the center of the escape wheel and an end of the distal part of the pallet of the anchor increases compared to the same distance before the anchor made contact with the tooth of the escape wheel , i.e. before the lever flexes, and/or relative to the distance between the center of the escape wheel and one end of the distal part of the other pallet (in case both pallets have the same dimensions, which is generally the case).

The escapement according to the invention is well suited to be used in combination with an oscillator having an amplitude of oscillation of less than 10°.

The invention also relates to a timepiece mechanism comprising the escapement according to the invention and an oscillator having an amplitude of oscillation of less than 10°, the anchor of the escapement being linked to the oscillator.

[0026] In a preferred variant, the escapement and the oscillator of the watch mechanism according to the invention are part of a single one-piece piece, for example a plate cut from a silicon wafer (or "wafer") or from a other material. In a preferred embodiment, the escapement and the oscillator of the watch mechanism are manufactured using manufacturing techniques usually used for the manufacture of semiconductors or MEMS.

The present invention also relates to a movement comprising the escapement or the timepiece mechanism according to the invention.

The present invention also relates to a watch comprising the escapement or the mechanism or the movement according to the invention.

Brief description of figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: FIG. 1 illustrates a top view of part of an embodiment of an exhaust according to FIG. 'invention. FIG. 2A illustrates a top view of another part of an embodiment of the escapement according to the invention, in which the tooth of the escapement wheel cooperates with the rest surface of the pallet of the anchor, thus bending the stem of the arm to which it belongs. Figure 2B illustrates a top view of part of the embodiment of the escapement of Figure 1, in which the tooth of the escapement wheel cooperates with the resting surface of the pallet of the pallet, in thus bending the stem of the arm to which it belongs. Figure 3 illustrates another top view of part of the escapement embodiment of Figure 1, in which the tooth of the escapement wheel continues to cooperate with the resting surface of the pallet of the anchor. Figure 4 illustrates a top view of part of the embodiment of the escapement of Figure 1, in which the tooth of the escapement wheel cooperates with the impulse point of the pallet of the pallet. FIG. 5 illustrates another top view of part of the embodiment of the escapement of FIG. 1, in which the tooth which cooperated with the palette of the anchor has disengaged from this palette. FIG. 6 illustrates another top view of an embodiment of the timepiece mechanism according to the invention, comprising an escapement according to the invention and an oscillator.

Example(s) of embodiment(s) of the invention

[0030] Figure 1 illustrates a top view of an embodiment of a rubbing rest escapement 100 according to the invention. In this figure, the rubbing rest escapement 100 includes an anchor 2 (partially illustrated) and an escape wheel 1.

The escape wheel comprises a hub 3 intended to pivot around an axis of rotation 4. A plurality of arms 10 extend from the hub 3, for example radially.

In the illustrated variant, each arm 10 comprises a blade 11 and a distal part 12. In the illustrated variant, the distal part 12 comprises a first protuberance 120, forming a tooth of the escape wheel intended to interact with the anchor 2. The blade 11 comprises an end 111 in correspondence of the distal part 12 and a body 110 connecting the end 111 to the hub 3.

In the variant illustrated, the distal portion 12 is substantially T-shaped and comprises a first portion 124 and a second portion 121 substantially straight. The second portion comprises the first protrusion 120 and a second protrusion 122. The first portion 124 is substantially perpendicular to the second portion 121. In the variant illustrated, the first portion 124 is not strictly perpendicular to the second portion 121: indeed the free end of the first protuberance 120 is bent towards the hub 3, because it forms the impulse plane. In the variant (not shown) where the impulse plane is at the level of the pallets of the anchor, the first portion 124 can be strictly perpendicular to the second portion 121.

However, it should be understood that the presence of the second protuberance 122 is not essential for the operation of the escapement according to the invention. Its presence, however, makes it possible to make the distal part 12 symmetrical. In addition, the T-shape of the distal part 12 allows a reduction in its mass compared to other possible shapes.

In the variant illustrated, the first portion 124 of the end part 12 forms with the blade 11 an angle α close to but not identical to 180°, in particular for space constraints.

The anchor 2 comprises two vanes 20, only one of which is visible in FIG. 1. The vane comprises two surfaces, a first surface (rest or stop surface) 21 and a second surface 22. In the variant illustrated, the first surface (rest or stop surface 21) is substantially planar and the second surface 22 is curved. The two surfaces define a tip 25. In the illustrated embodiment, the contact between the extremal part 12 and the pallet during the pulse is punctual, in correspondence of the tip 25. The tip 25 therefore comprises a pulse point ; in the illustrated embodiment, the impulse surface is located on the extreme part 12 of the escape wheel, in particular on its first end 120 as discussed above.

In the variant of Figure 1, the escapement wheel 1 also comprises several stop elements 15, which also extend from the hub 3. In the variant illustrated, these stop elements are placed between two arms 10 adjacent. In a preferred variant, each abutment element 15 is rigid. Their main function is to limit the maximum amplitude of deformation of the blades 11, as will be seen below. Another function is that of limiting the movement of the arm 10 in the event of impact.

In the variant illustrated, each abutment element 15 has a substantially rectangular shape, with the distal end having a substantially curved first surface 125 and a substantially straight second surface 126, as best seen in Figure 2B. The presence of a curved surface 125 makes it possible to limit or eliminate the risk of breakage or damage to the blade 11 (or in general to the arm 10) during its contact between the abutment element 15, which in a variant is performed in correspondence of this curved surface 125.

In the variant illustrated in Figure 2A, each abutment element 15 has a substantially rectangular shape, with the distal end comprising only straight surfaces. These rectilinear surfaces define corners 124.

In a preferred variant, the length of each abutment element 15 is smaller than the length of the arm 10. In the variant illustrated in Figures 2A and 2B, the length of each abutment element 15 corresponds substantially to the length of blade 11.

In the variant illustrated in Figures 1 to 5, the escape wheel comprises several stop elements 15 each interposed between two arms 10.

In the variant in Figures 1 to 5, the blade 11 is elastic and the distal portion 12 is rigid. In a preferred variant, the blade 11 and the distal part 12 form a single one-piece piece. In this variant, the rigidity of the end part 12 is obtained by increasing its width, that is to say the dimension of the end part 12 which belongs to the plane of FIG. 1 and which is substantially perpendicular to the main dimension of the blade 11, that is to say its length. In a preferred variant, the width of the distal part 12 is approximately 10 times the width of the blade 11. In a preferred variant, the width of the distal part 12 is approximately 100 μm and the width of the blade 11 is about 10 µm. In a preferred variant, the distal part 12 and the blade 11 are cut from the same plate, for example and in a non-limiting way from a silicon plate. In a variant, the thickness of this plate and/or as a general rule the thickness of both the end part 12 and the blade 11 is of the order of magnitude of 100 μm. A surface treatment can be applied to the distal part, to improve its tribological properties. This surface treatment may be absent from the blades 11.

[0043] In another variant, the distal part 12 and the blade 11 are made of the same material, for example and in a non-limiting manner of metal, metallic glass, ceramic, etc.

In another variant, the distal part 12 and the blade 11 are made of the same material but form two separate parts, linked together by connection means, preferably non-removable connection means.

In another variant, the distal part 12 and the blade 11 are made of two different materials. They can form two separate parts, interconnected by connection means, preferably non-removable connection means. In a variant, they are made by a bi-material manufacturing process, for example and in a non-limiting manner by the manufacturing process described in the document published under the number WO2018197516 filed by the applicant.

[0046] Figure 2B illustrates a top view of a portion of the escapement embodiment 100 of Figure 1, wherein the tooth of the escapement wheel 121 contacts the rest surface 21 of the pallet 20 of the anchor, thus bending the blade 11 of the arm 10 to which it belongs.

Indeed, as can be seen by comparing Figure 1 with Figure 2B, the blade 11 is no longer substantially parallel to the stop element 15, but it is deformed. Following its bending/deformation, the radius of the arc of a circle C2 having as its center the center of rotation of the escape wheel and passing through the tooth 121, is reduced compared to the radius of the arc of a circle C1 having like the same center but passing through another tooth at the end of an unbent blade 11, for example a blade 11 adjacent to the bent blade.

In a preferred variant, the absolute value of the radius reduction, illustrated in FIGS. 2A and 2B by the reference d, belongs to the range 5 μm-15 μm.

In a preferred variant, this range is independent of the length of the arm 10.

This reduction d makes it possible to reduce the engagement of the tooth 121 with the pallet. It thus guarantees that a small shock given to the escapement 100 according to the invention is sufficient to start the operation of the escapement 100. In another variant, this reduction d allows the escapement 100 to be able to self-start.

If the escape wheel 1 includes abutment elements, the bending of the blade 11 is limited by the contact between the blade 11 and the abutment element 15.

In the example of Figure 2A, the blade presses in correspondence of its end 111 against the abutment element 15, in particular against a corner 124 of its end. In the example of Figure 2B, the blade 11 presses in correspondence of its body 110 against the abutment element 15, in particular against the curved surface 125 of the abutment element 15: in this way the risk of rupture or damage to the blade 11 during contact between the abutment element 15 and the arm 10 in correspondence of this curved surface 125 is reduced or even eliminated.

In a preferred variant, the distal part 12 never comes into contact with the abutment element 15. In a preferred variant, it is the blade 11, for example its distal end 111 or its body 110, which touches the abutment element 15. In another variation, the abutment element 15 comes into contact with the distal part 12. In yet another variation, the abutment element 15 comes into contact in a distributed manner with the blade 11 and the distal part 12.

The situation illustrated in Figures 2A and 2B corresponds to the moment in which the exhaust 100 according to the invention is stopped. This situation also corresponds to the moment of operation of the escapement 100 according to the invention, in which the tooth 120 cooperates with the rest surface 21 of the pallet 20 (rest phase).

[0055] During the rest phase, the cooperation between the lever 2 (which oscillates) and the escapement wheel 1 causes the tooth 120 to slide along the rest surface 21 until it is in correspondence of its tip 25, as shown in Figure 3.

Then, as illustrated in Figure 4, the distal portion 12, in particular its rectilinear portion 121, cooperates with the second surface 22 of the pallet 20. During this contact, the escape wheel advances in the direction indicated by arrow F1. During this advancement, the distal part 12 (rigid) accompanies the anchor 2. By resuming its undeformed position, the arm 10 provides an impulse to the anchor.

The tooth 120 is then released from the pallet 20, as illustrated in Figure 5. After this release, it resumes its shape and its initial dimensions (corresponding to those of Figure 1). In other words, it defines the same arc of circle C1 having as its center the center of rotation of the escape wheel and passing through the end of an unflexed blade 11.

After this release, the distal part 12 of the arm 10 whose blade 11 was bent oscillates around the end 111 freely in the directions indicated by the arrow F2 in Figure 5.

During its bending, the blade 11 stores energy (rest phase of the escapement 100). Part of this energy is then returned to the anchor 2 during the impulse phase (FIG. 4) and part is lost during the free oscillations of the distal part 12 once it is no longer in contact with the anchor (Figure 5, arrow F2).

FIG. 6 illustrates another top view of an embodiment of the watch mechanism 1000 according to the invention, comprising an escapement 100 according to the invention and an oscillator 200, for example a regulating member.

In this variant, the oscillator has an oscillation amplitude of less than 10°. In this variant, the oscillator 200 and the escapement 100 are cut from the same wafer, for example and without limitation a silicon plate.

The appended figures illustrate a first variant of the invention in which the arm 10 comprises a flexible portion (the blade 11) and a rigid portion (the distal part 12), while the anchor 2, and in particular its pallets, is (are) rigid.

[0063] The concept can however be symmetrized: in a second variant, the escape wheel 1 is rigid whereas the anchor 2 comprises a pallet comprising a body and a distal part, and in which - the body comprises an elastic portion , - The distal part of the paddle comprises a rigid portion.

[0064] In this variant, the body of the pallet is arranged to bend during the rest phase when the distal part comes into contact with the tooth of the escape wheel, so that the distance between the center of the escapement wheel and one end of the distal part of the pallet of the anchor increases during bending, so as to facilitate the starting of the escapement.

In this variant, the increase in this distance during bending belongs to the range of 5 μm-15 μm. The two variants can be combined, i.e. it is possible that both the anchor 2 and the arm 10 comprise: an elastic portion, a rigid portion, intended to interact with the arm 10 respectively with the anchor 2, the elastic portion being arranged to flex during a phase of rest when the arm 10 comes into contact with the anchor 2, so as to facilitate the starting of the 'exhaust.

Reference numbers used in the figures

[0066] 1 Escapement wheel 2 Anchor 3 Hub 4 Axis of rotation 10 Arm 11 Blade 12 Distal part 15 Stop element 20 Pallet 21 First surface (resting surface 22 Second surface 25 Tip (pulse point) 100 Exhaust 110 Blade body 111 Blade end 120 First protrusion (tooth) 121 Straight portion 122 Second protrusion 124 Corner of the abutment element 125 Curved surface of the abutment element 126 Straight surface of the abutment element 200 Oscillator 1000 Clockwork mechanism d Radius reduction C1 First arc C2 Second arc F1 Arrow F2 Arrow α Angle

Claims (14)

1. Exhaust (100) at friction rest comprising: – an anchor (2), – an escape wheel (1) comprising: – a hub (3); an axis of rotation around which the hub (3) is intended to rotate, – a plurality of arms (10) extending from the hub (3), and wherein the anchor (2) and/or one arm of said plurality of arms (10) comprises: – an elastic portion, – a rigid portion, intended to interact with the arm (10) respectively with the anchor (2), said elastic portion being arranged to flex during a rest phase when the arm (10) comes into contact with the anchor (2), so as to facilitate starting of said escapement. 2. Exhaust according to claim 1, wherein said anchor (2) is rigid, wherein the arm (10) comprises a blade (11) and a distal part (12), and wherein – said blade (11) comprises said elastic portion, – said distal part (12) comprises said rigid portion, said blade (119) being arranged to flex during said rest phase upon contact of the tooth (120) with the pallet (2), so that the radius of the escape wheel (1) in correspondence of said rigid portion (120) is reduced during its bending, so as to facilitate starting of said exhaust (100). 3. Escapement according to claim 1, wherein said escapement wheel (1) is rigid and comprises at least one tooth (120), wherein said anchor (2) comprises a pallet (20) comprising a body and a distal part , and in which – said body comprises said elastic portion, – said end part includes said rigid portion, said body being arranged to flex during said rest phase upon contact of the end portion with the tooth (120) of the escape wheel, such that the distance between the center of the escape wheel and one end of the distal part of the pallet of the anchor increases during bending, so as to facilitate starting of said escapement (100). 4. Exhaust according to claim 2, said reduction (d) of the radius of the escape wheel (1) being comprised in the range between 5 µm and 15 µm 5. Exhaust according to one of claims 2 and 4, said blade (10) storing energy during the rest phase during its bending, said energy being partly restored to the anchor (2) during a phase of 'impulse. 6. Exhaust according to one of claims 2,4 and 5, said distal portion (12) being substantially T-shaped. 7. Exhaust according to the preceding claim, said distal part comprising a substantially rectilinear portion (121) arranged to cooperate with a pulse point (25) of a pallet (20) of the anchor (2) during a phase of impulse. 8. Exhaust according to one of claims 2,4 and 7, comprising a stop element (15) between two arms (10) to limit said bending of said blade (11) during the rest phase. 9. Exhaust according to the preceding claim, comprising several abutment elements (15) each interposed between two arms (10). 10. Exhaust according to one of claims 8 and 9, said abutment element being arranged to come into contact with the blade (11) during the bending of said blade (11). 11. Clockwork mechanism comprising the escapement according to one of claims 1 to 10 and an oscillator having an oscillation amplitude of less than 10°, said lever (2) being linked to said oscillator. 12. Timepiece mechanism according to claim 11, said escapement and said oscillator being made by cutting from a single one-piece piece, for example from a plate, in particular from a silicon wafer. 13. Movement comprising the escapement according to one of claims 1 to 10 or the mechanism according to one of claims 11 to 12. 14. Watch comprising the escapement according to one of claims 1 to 10 or the mechanism according to one of claims 11 to 12 or the movement according to claim 13.