CH715864B1 - Blocking device for a watch movement. - Google Patents

Abstract

The invention relates to a blocking member (10) of a toothed wheel (20), the blocking member (10) being formed in one piece and comprising: a frame (101), a first rocker (102) comprising a first locking tooth (102d) of the toothed wheel (20), a first elastic return portion (103) connecting the first rocker (102) to the frame (101), characterized in that: the locking member (10) comprises at least: a second rocker (102) comprising a second locking tooth (102d) of the toothed wheel (20), a second elastic return portion (103) connecting the second rocker (102) to the frame (101), and in that the first rocker (102) and said at least one second rocker (102) are arranged to sequentially block the rotation of the toothed wheel (20).

Description

The present invention generally relates to a locking or clutch member for a timepiece movement, for example a timepiece movement of a watch.

[0002] Locking devices such as those described in documents WO011120180A1 or EP2037335A2 are known in the prior art, in which a locking member is arranged to block rotation of a toothed wheel in a first direction of rotation, and leave the toothed wheel free to rotate in a second direction of rotation. On the other hand, these systems have in particular the disadvantage of allowing a large displacement of the toothed wheel between two stop positions of the latter. As a result, the toothed wheel must advance a large angular value to reach a next stop position, and can move back a large angular value if it does not succeed, which generates significant "dead times". in the case where the blocking member is part of a winding device for example.

An object of the present invention is to respond to the drawbacks of the documents of the prior art mentioned above and in particular, first of all, to propose a blocking member and a blocking device which limits downtime or does not require the cogwheel (typically a ratchet or wolf-tooth wheel) to be rotated by a large angular value between two stop positions.

For this, a first aspect of the invention relates to a member for locking a toothed wheel of a watch movement, the toothed wheel preferably forming a ratchet, the locking member being formed in one piece and comprising: a chassis, a first lever comprising a first blocking tooth arranged to block a rotation of the toothed wheel according to a first direction of rotation, and to leave free the rotation of the toothed wheel according to a second direction of rotation, a first elastic return portion connecting the first rocker to the frame and forming means for positioning the first rocker on the frame, characterized in that: the blocking member comprises at least: a second rocker comprising a second blocking tooth arranged to block the rotation of the toothed wheel according to the first direction of rotation, and to leave free the rotation of the toothed wheel according to the second direction of rotation, a second elastic return portion connecting the second rocker to the frame and forming means for positioning the second rocker on the frame, and in that the first rocker and said at least one second rocker are arranged to sequentially block the rotation of the toothed wheel in the first direction of rotation.

The locking member of the above implementation comprises a plurality of latches, each connected to the frame in one piece or in one piece by a respective elastic return portion. Each elastic return portion also forms positioning means for positioning each respective rocker with respect to the frame, so as to sequentially block the toothed wheel. In other words, each of the plurality of flip-flops is offset (typically angularly) relative to the other flip-flops to lock the toothed wheel at an intermediate position relative to the other flip-flops. As a result, only one rocker locks the gear wheel at a time. This implementation makes it possible to limit a return travel of the toothed wheel between two stop positions and dead times. It is understood that such a unidirectional blocking member here can be part of a clutch device and just as well be called a clutch member, and in particular a one-way clutch member.

[0006] Advantageously, the blocking member comprises a plurality N of rockers each comprising a blocking tooth arranged to block the rotation of the toothed wheel according to the first direction of rotation, and to leave free the rotation of the toothed wheel, according to the second direction of rotation, and the toothed wheel has an angular pitch α, and two locking teeth of two adjacent rockers are separated by an angular distance δ defined by: δ = M. α + α / N, where M is an integer, the toothed wheel comprising a number of teeth Z, then preferably: M=Z/N.

[0007] According to the implementation above, the rockers are distributed in a regular manner so that each locks the toothed wheel sequentially with the smallest clearance or backtracking possible, always the same. Thus, in a winding or clutch function, the “blind spots” or “dead times” or even backward strokes are limited, so that the engagement is almost immediate.

[0008] Advantageously, each elastic return portion, forming the positioning means of each respective rocker, preferably leaves free (or preferentially free) at least one degree of freedom of each respective rocker, according to a rotation of an axis parallel to a axis of rotation of the cogwheel. In other words, each flip-flop can pivot to let the toothed wheel pivot in the second direction of rotation. It should be understood that each elastic return portion preferentially allows movement in pivoting, and has a much greater stiffness for the other degrees of freedom (a stiffness preferably 10 times or 100 times or 1000 times greater for the other degrees of freedom). In practice, only one displacement in rotation is allowed, the other displacements are negligible.

[0009] Advantageously, each elastic return portion, forming the positioning means of each respective rocker, defines a pivot axis of each respective rocker. Each rocker, formed in one piece with each respective elastic return portion and the frame, can pivot around an axis of rotation, defined by the elastic deformation of each elastic return portion.

[0010] Advantageously, each elastic return portion is arranged to: define a blocking position of each respective rocker, in which each rocker is arranged to block the rotation of the toothed wheel according to the first direction of rotation, allowing each respective rocker to pivot towards an exhaust position in which each rocker is arranged to allow free rotation of the toothed wheel in the second direction of rotation, exert an elastic return force on each respective rocker from the exhaust position to the blocking position.

[0011] Advantageously, each latch comprises: a first arm supporting the locking tooth, a second arm supporting a stop, arranged to come into mechanical stop with the frame, when the locking tooth blocks the rotation of the toothed wheel in the first direction of rotation. In particular, the first arm and the second arm are oriented with respect to each other to follow the periphery of the toothed wheel, and schematically each lever has a boomerang or "banana" shape. Furthermore, the abutment allows the rocker (in the locking position) to rest on the frame, which secures or locks the stop positions of the toothed wheel.

[0012] Advantageously, the stopper is separated by an angular distance from the locking tooth by an angular distance δ1 defined by: δ1 = M1 . α + k, in which M1 is an integer and α/3<k<2α/3 and ideally k=α/2. This implementation facilitates the disengagement of each latch, with limited bulk. Indeed, during a disengagement or escapement of the toothed wheel, the abutment can pivot towards a recess in the toothing of the toothed wheel, without however interfering with the latter.

[0013] Advantageously, each elastic return portion of each rocker comprises two flexible blades, each flexible blade has a width e and a thickness b respecting the following ratio: 2 < e/b < 20, and preferably: e/b=10. Such an implementation provides good elasticity and deformation, while remaining feasible.

[0014] Advantageously, the two flexible blades have a common portion so as to form a crosspiece. In other words, the flexible blades have a junction, which makes it possible to precisely define the position of the (virtual) axis of rotation or pivoting of the respective rocker.

[0015] Advantageously, the two flexible blades form a crosspiece of which two adjacent branches form an angle comprised in a range of values ranging from 10° to 170° and preferably from 30° to 120°.

[0016] Advantageously, each flexible blade has an angular stiffness k of between: 0.001 Nmm/° < k < 1 Nmm/°.

[0017] Advantageously, a first flexible strip connects the frame to the end of the first arm, and a second flexible strip connects the frame to the end of the second arm. This implementation makes it possible to maximize the lengths of the flexible strips.

[0018] Advantageously, the blocking member is made of silicon. Such a silicon part has many advantages: its manufacture, typically by etching, makes it possible to give complex shapes, the coefficients of friction are low, and the elastic resistance is high.

A second aspect of the invention relates to a locking device, comprising: a locking member according to the first aspect of the invention, a toothed wheel, preferably forming a ratchet.

[0020] Watch movement comprising at least one blocking member according to the first aspect of the invention.

Watch comprising at least one blocking member according to the first aspect of the invention.

Other characteristics and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the appended drawings, wherein : FIG. 1 represents a top view of a locking member according to the invention; FIG. 2 represents a perspective view of the blocking member of FIG. 1; FIG. 3 represents a top view of a subassembly formed by the locking member of FIG. 1, with a toothed wheel; FIG. 4 represents a perspective view of the subassembly of FIG. 3; - Figure 5 shows a top view of the subassembly of Figure 3, mounted on a pawl wheel; Figure 6 shows a perspective view of the sub-assembly mounted on a pawl wheel of Figure 5.

Figure 1 shows a top view of a locking member 10 according to the present invention, comprising three rockers 102, each connected to the same frame 101 by a portion of respective elastic return portion 103, integrally. Indeed, the locking member 10 is formed in one piece, which facilitates the assembly operations of a watch movement.

Advantageously, the blocking member 10 is formed in silicon, by a DRIE („Deep Reaction Ion Etching“) etching process, or even in Ni or NiP using a UV-LiGA lithography process („ Lithography, Galvanoformung, Abformung“). These methods make it possible to manufacture such a part of complex shape (the frame, the elastic return portions, the levers) in one piece, or in one piece with great precision.

In detail, each rocker 102 has a first arm with a locking tooth 102d and a second arm with a stop 102b. Each elastic return portion comprises two flexible blades 103f1 and 103f2, each of which has one end connected to the first or to the second arm, another end connected to the frame 101 and join to form a spider 103c.

This architecture makes it possible to define a pivot type joint between each rocker 102 and the frame 101. Indeed, each elastic return portion 103, via the crosspiece 103c formed by its flexible blades 103f1 and 103f2, defines an axis of rotation (Virtual and normal to the plane of FIG. 1) of each rocker 102 respectively, at the level of the spider 103c.

As shown in Figure 2 in perspective, each flexible blade 103f1 and 103f2 of each elastic return portion 103 has a width e and a thickness b respecting the following ratio: 2 < e/b < 20, and preferably: e/b = 10

Such an implementation provides good elasticity to each elastic return portion 103, as will be explained below. By way of example, each flexible blade 103f1, 103f2 has an angular stiffness k comprised between: 0.001 Nmm/° < k < 1 Nmm/°

[0029] Furthermore, the locking member 10 comprises a smooth hole 104 to allow fixing and positioning on another part of the watch movement by a driven pin, and two splined holes 105, to allow fixing by a driven pin / glued. We can of course consider other methods of fixing (by screwing, elastic interlocking, etc.)

Finally, as shown in Figure 1, the elastic return portions 103 each position their respective rocker 102 relative to the frame 101 in a stable locking position, or rest position.

As shown in Figure 3, the locking member 10 is arranged to cooperate with a toothed wheel 20 of angular pitch α. In particular, the blocking member 10 is arranged to block a rotation of the toothed wheel 20 according to a first direction of rotation (clockwise), and to leave free the rotation of the toothed wheel 20 according to a second direction of rotation (counterclockwise). hourly). In the case shown, the toothed wheel 20 is a ratchet, but it is possible to envisage other embodiments of the shape of the teeth, for example a toothed wheel.

Indeed, each 102d locking tooth of each rocker 102 can block the clockwise rotation of the toothed wheel 20, and in Figure 3 where the rockers 102 are numbered 102-1, 102-2, 102- 3 to distinguish them (but this numbering is arbitrary and is only used for figure 3), it is the locking tooth 102d-2 of the rocker 102-2 which prevents clockwise rotation of the toothed wheel 20.

[0033] With regard to the rocker 102-1, during the anti-clockwise rotation of the toothed wheel 20, the latter will "push" the locking tooth 102d-1 to rotate the rocker 102-1 in a clockwise direction. , around a theoretical axis passing through the spider 103c-1, to go into an exhaust position. The elastic return portion 103-1 will exert a return force on the rocker 102-1 to bring it back from the exhaust position to the blocking position.

Figure 3 also shows a particular arrangement of flip-flops 102-1, 102-2, 102-3. Indeed, the latter are angularly offset from each other by an angle δ defined according to: δ = M. α+α/N, in which M is an integer, N is the number of flip-flops and if the toothed wheel 20 comprises a number of teeth Z, then preferably: M=Z/N.

[0035] In the particular case of FIG. 3, δ=3. α + α / 3, which makes it possible to block the toothed wheel 20 every 1/3 of its pitch α. This limits the backlashes (clockwise) of the toothed wheel 20 during a winding or disengagement operation. In other words, each flip-flop 102-1, 102-2, 102-3 locks the toothed wheel sequentially and offset in time.

As regards the blocking position of each latch 102-1, 102-2, 102-3, each latch 102-1, 102-2, 102-3 comprises a stop 102b to secure and guarantee this locking position. blocking, for example during a shock which would generate too great a force on the toothed wheel 20 in the clockwise direction. In the case of the rocker 102-2 which blocks the toothed wheel 20 in FIG. 3, if a force exerted by the toothed wheel 20 causes a deformation of the elastic return portion 103-2, then the rocker 102-2 would pivot in the anti-clockwise direction and the stop 102b-2 would come into abutment on the frame 101, so that the toothed wheel 20 could not pivot any further clockwise.

Finally, Figure 3 shows the rocker 102-3 whose arm which supports the abutment is in contact or almost in contact with the toothed wheel 20, which guarantees that the locking tooth of this rocker 102-3 will enter well in abutment against the toothed wheel 20 (in this position of the lever 102-3 imposed by the contact or the near contact between the stop arm and the toothed wheel 20, the portion of the top of the locking tooth 102d-3 is on a diameter smaller than the outer diameter of the toothed wheel 20).

This function is guaranteed because the stopper is separated from the locking tooth by an angular distance δ1 defined by: δ1 = M1 . α + k, in which: M1 is an integer and α / 3 < k < 2α / 3 and ideally k = α / 2. In the particular case of figure 3, δ1 = 2 . α + α / 2

Figure 4 shows the subset of Figure 3 in perspective for clarity. In the case shown in FIG. 4, the toothed wheel 20 is blocked by the locking tooth 102d of the rocker 102 located approximately at 11 o'clock, and if the toothed wheel 20 pivots in the anti-clockwise direction by α/3, then it is the rocker 102 located at 6 o'clock which will engage with the toothed wheel to block any backtracking in the clockwise direction.

[0040] In the case of a winding mechanism, or a clutch mechanism, the toothed wheel 20 can only move back here by an angle α / 3 at most, instead of an angle α s' there is only one flip-flop or if the three flip-flops are not shifted. In the present case with three flip-flops 102 shifted sequentially, the recoil amplitude is divided by three, which reduces the dead time or blind spots accordingly.

[0041] Figures 5 and 6 show the front and in perspective the subset of Figures 3 and 4 cooperating with a pawl door wheel 30. It is possible to consider integrating this pawl door wheel 30 in a clutch or winding mechanism of watch. Typically, the pawl wheel 30 is integral with the toothed wheel 20, and the blocking member is itself integral with a bridge or a plate of the watch, so that it is possible to block the rotation of the wheel ratchet 30 in the clockwise direction, with little backlash of the ratchet wheel 30 between two stop positions (at most 1/3 of the angular pitch of the toothed wheel 20), so that dead times are reduced.

It will be understood that various modifications and/or improvements obvious to those skilled in the art can be made to the various embodiments of the invention described in the present description without departing from the scope of the invention defined by the appended claims. In particular, reference is made to three rockers, but the blocking member can comprise two, four or more rockers. In addition, the elastic return portion is formed mainly by two flexible strips, but one can envisage a single flexible strip, or a torsion bar for example.

Claims (16)

1. Locking member (10) of a toothed wheel (20) of a watch movement, the toothed wheel (20) preferably forming a ratchet, the locking member (10) being formed in one piece and comprising: – a chassis (101), – a first rocker (102) comprising a first locking tooth (102d) arranged to block a rotation of the toothed wheel (20) according to a first direction of rotation, and to leave free the rotation of the toothed wheel (20) according to a second rotating direction, – a first elastic return portion (103) connecting the first rocker (102) to the frame (101) and forming means for positioning the first rocker (102) on the frame (101), characterized in that: the locking member (10) comprises at least: – a second rocker (102) comprising a second locking tooth (102d) arranged to block the rotation of the toothed wheel (20) according to the first direction of rotation, and to leave free the rotation of the toothed wheel (20) according to the second rotating direction, – a second elastic return portion (103) connecting the second rocker (102) to the frame (101) and forming means for positioning the second rocker (102) on the frame (101), and in that the first rocker (102) and said at least one second rocker (102) are arranged to sequentially block the rotation of the toothed wheel (20) in the first direction of rotation. 2. Locking member (10) according to the preceding claim, comprising a plurality N of rockers (102) each comprising a locking tooth (102d) arranged to lock the rotation of the toothed wheel (20) in the first direction of rotation, and allowing the toothed wheel (20) to rotate freely, in the second direction of rotation, in which the toothed wheel (20) has an angular pitch α, and in which two locking teeth (102d) of two adjacent rockers (102) are separated by an angular distance δ defined by: δ = M. α + α / N, where M is an integer, the toothed wheel (20) comprising a number of teeth Z, then preferably: M=Z/N. 3. Locking member (10) according to one of the preceding claims, wherein each elastic return portion (103), forming the positioning means of each rocker (102) respectively, leaves free at least one degree of freedom of each rocker (102) respective, according to a rotation around an axis parallel to an axis of rotation of the toothed wheel (20). 4. Blocking member (10) according to one of claims 1 or 2, wherein each elastic return portion (103), forming the positioning means of each rocker (102) respectively, defines a pivot axis of each rocker (102) respectively. 5. Locking member (10) according to one of the preceding claims, wherein each elastic return portion (103) is arranged to: – define a blocking position of each rocker (102) respectively, in which each rocker (102) is arranged to block the rotation of the toothed wheel (20) according to the first direction of rotation, – allowing each respective rocker (102) to pivot towards an exhaust position in which each rocker (102) is arranged to allow free rotation of the toothed wheel (20) in the second direction of rotation, - Exert an elastic return force on each rocker (102) respectively from the exhaust position to the blocking position. 6. Blocking member (10) according to one of the preceding claims, wherein each rocker (102) comprises: – a first arm supporting the locking tooth (102d), - a second arm supporting a stop (102b), arranged to come into mechanical stop with the frame (101), when the locking tooth (102d) blocks the rotation of the toothed wheel (20) in the first direction of rotation. 7. Locking member (10) according to the preceding claim, and according to claim 2, wherein the abutment (102b) is separated from the locking tooth (102d) by an angular distance δ1 defined by: δ1 = M1 . α + k, in which : M1 is an integer and α / 3 < k < 2α / 3 and ideally k = α / 2. 8. Blocking member (10) according to one of the preceding claims, wherein each elastic return portion (103) of each rocker (102) comprises two flexible blades (102f1, 102f2), each flexible blade (102f1, 102f2) having a width e and a thickness b respecting the following ratio: 2 < e/b < 20, and preferably: e/b = 10 9. Locking member (10) according to the preceding claim, wherein the two flexible blades (102f1, 102f2) have a common portion so as to form a spider (103c). 10. Locking member (10) according to the preceding claim, in which the two flexible blades (102f1, 102f2) form a spider (103c) of which two adjacent branches form an angle comprised in a range of values ranging from 30° to 120° . 11. Locking member (10) according to one of claims 8 to 10, wherein each flexible blade (102f1, 102f2) has an angular stiffness k of between: 0.001 Nmm/° < k < 1 Nmm/° 12. Locking member (10) according to one of claims 8 to 11, and according to claim 6, wherein a first flexible blade (102f1, 102f2) connects the frame (101) to the end of the first arm, and a second flexible blade (102f1, 102f2) connects the frame (101) to the end of the second arm. 13. Blocking member (10) according to one of the preceding claims, formed of silicon. 14. Blocking device, comprising: a locking member (10) according to one of claims 1 to 13 and a toothed wheel (20), preferably forming a ratchet. 15. Watch movement comprising at least one locking member (10) according to one of claims 1 to 13. 16. Watch comprising at least one locking member (10) according to one of claims 1 to 13.