Timepiece movement comprising an automatic winding mechanism

Abstract

The present invention relates to a timepiece movement (10) comprising in particular a frame (12, 12a, 12b), a gear train (11), a barrel (60), and an automatic winding mechanism for winding the barrel (60). The winding mechanism comprises a winding weight (14) mounted in an articulated manner on the frame (12a, 12b) by way of rotary arms (30a, 30b, 30c, 30d) so that the winding weight (14) can perform a circular translation movement. The winding mechanism further comprises transmission means arranged to transmit the movement of the winding weight (14) to the barrel (60). The winding weight (14) is connected to the rotary arms (30a, 30b, 30c, 30d) so as to constrain the circular translation movement of said weight (14) in a plane parallel to the general plane of the timepiece movement. The rotary arms (30a, 30b, 30c, 30d) are moreover free to pivot through 360°.

Description

Watch movement including an automatic winding mechanism Technical field

[0001] The present invention relates to the field of watchmaking and more particularly to a watch movement comprising an automatic winding mechanism. This mechanism comprises a winding mass arranged to perform a circular translational movement. State of the art

[0002] Automatic winding mechanisms most often use a semi-circular oscillating weight pivotally mounted in the center of the watch movement along an axis perpendicular to its general plane. A disadvantage of this type of oscillating weight lies in its location on the back of the watch case, hiding, at least in part, the watch movement. Such an arrangement is not always desirable, especially when the back is a sapphire crystal, in order to reveal an original visual aspect of the movement.

[0003] In order to solve this problem, CH706350 proposes a watch movement comprising a frame, various organs, including a barrel and gears mounted on the frame as well as an automatic winding mechanism for recharging the barrel. This winding mechanism comprises a winding mass and transmission means arranged to transmit the movement of the winding mass to the barrel to wind it. The winding mass is mounted articulated on at least two arms pivotally mounted on the frame. The winding mass is further arranged to perform a circular translation movement which can be complete around the frame in a plane perpendicular to the general plane of the watch movement.

[0004] It is therefore necessary to provide a significant volume in the watch case to allow the movements of the winding mass in the perpendicular plane mentioned above. This has an impact on the thickness of the watch case, which must be sufficient to ensure that the amplitude of the movements of the mass allows efficient winding of the barrel.

[0005] CH 157093 and CH 168493 disclose another example of a self-winding watch movement, comprising an unconventional oscillating weight. The winding mechanism comprises a frame comprising in particular a barrel and a winding weight. The latter is connected to the frame by several arms whose axis of rotation is parallel to the general plane of the watch movement. The distance between the winding weight and the frame varies depending on the position of the weight. It is therefore necessary, like CH706350, to provide sufficient volume in the watch case for the movement of the winding weight.

[0006] Furthermore, the plane in which the winding mass oscillates according to the aforementioned mechanisms is not optimal in relation to the most frequent general movements of a wearer's arm, which are swinging movements of the arm along the body. This has a significant impact on the winding efficiency of the barrel.

[0007] CH707942A2 relates to an automatic winding mechanism for a watch movement comprising two winding masses connected to a barrel in order to wind it by their rotational movement. The two winding masses have between them a rigid mechanical synchronization connection in the form of a connecting rod.

[0008] An aim of the present invention is therefore to propose a watch movement comprising an automatic winding mechanism which does not hide the movement while resolving, at least in part, the aforementioned problems of the prior art. Brief summary of the invention

[0009] This aim is achieved by a watch movement comprising in particular a frame, gear trains, a barrel and an automatic winding mechanism for winding the barrel. The winding mechanism comprises a winding mass mounted articulated on the frame by means of rotating arms so that the winding mass can perform a circular translational movement. The winding mechanism further comprises transmission means arranged to transmit the movement of the winding mass to the barrel. The winding mass is connected to the rotating arms so as to constrain the circular translational movement of the mass in a plane parallel to the general plane of the watch movement. The rotating arms are also free to pivot through 360°.

[0010] According to one embodiment, the watch movement further comprises an armature secured to the winding mass or forming a single piece with the mass. The rotating arms are pivotally connected to the armature. The rotating arms are further arranged to pivot in a plane located between the armature and the frame.

[0011] According to one embodiment, the winding mass comprises an unbalance.

[0012] According to one embodiment, the armature comprises at least a first and a second fixing part on which the rotating arms are connected, and at least a first and a second support each supporting a weight of the winding mass. The weights together form the unbalance of the winding mass. The fixing parts and the supports are each arranged alternately on the armature around a central part of the watch movement.

[0013] According to one embodiment, the weights are arranged on only one face of the frame.

[0014] According to one embodiment, the first and second fixing portions are each connected to the frame by two rotating arms.

[0015] According to one embodiment, the weights each comprise an external face intended to be mounted opposite a portion of the case middle of a watch case when the watch movement is mounted in the case, and an internal face opposite the external face. The internal face of at least one of the weights comprises a clearance to be able to partially envelop at least one member of the watch movement, in particular a gear train, when a circular translational movement is imparted to the winding weight.

[0016] According to one embodiment, at least one of the weights comprises a cutout for the passage of a control stem such as a time-setting stem.

[0017] According to one embodiment, the winding mass is articulated on the frame by means of three or four rotating arms.

[0018] According to one embodiment, the winding mass comprises three weights which are each arranged between two rotating arms.

[0019] According to one embodiment, the transmission means comprise a gear train engaged with the barrel ratchet. At least one of the rotating arms is secured to a transmission shaft comprising a transmission wheel engaged with the gear train and arranged to be driven in rotation by the rotation of said at least one rotating arm.

[0020] According to one embodiment, the transmission means comprise a pull lever and a push lever. The pull and push levers comprise at a first end a pawl configured to respectively pull and push a tooth of the barrel ratchet or of a wheel engaged with the barrel ratchet, alternately so that the barrel ratchet is actuated in rotation in a single direction. The pull and push levers each comprise a second end secured to one of the rotary arms.

[0021] According to one embodiment, at least one elastic member is integral with the winding mass. This elastic member is arranged to act on an actuable part of the traction lever and the push lever in order to constrain their respective pawl against the barrel ratchet or the wheel engaged with the ratchet.

[0022] Another aspect of the invention relates to a timepiece comprising the watch movement according to one of the aforementioned embodiments. Brief description of the figures

[0023] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: - figure 1 illustrates a perspective view of a watch movement comprising a winding mass according to one embodiment of the invention; - figure 2 illustrates a perspective view of the watch movement of figure 1 in another orientation, - figure 3 illustrates a view similar to figure 2 without the winding mass; - figures 4a and 4b illustrate a perspective view of the winding mass of figure 1 according to a first and a second orientation; - figure 5 illustrates a top view of the watch movement of figure 1 from the winding mass side; - figure 6 illustrates a sectional view of the watch movement of figure 5 according to AA; - figure 7 illustrates a perspective view of the kinematic chain connecting the winding mass to the barrel of the watch movement; - Figure 8 illustrates an enlarged view of the drive train of Figure 7; - figures 9a to 9d illustrate a sequence of circular translational movement of the winding mass; - figure 10a illustrates a simplified view of a watch movement comprising means for transmitting the movement of the mass to the barrel according to another embodiment, and - figure 10b illustrates a view similar to figure 10a without the winding mass. Examples of embodiments of the invention

[0024] With reference to figures 1 to 8, the watch movement 10 comprises a frame 12, 12a, 12b, various organs, including a barrel 60, gear trains 11 and an automatic winding mechanism for winding the barrel 60. The winding mechanism comprises a winding mass 14 connected to the frame 12 by several rotating arms, for example three or four rotating arms 30a, 30b, 30c, 30d so that a circular translational movement can be imparted to the winding mass 14 in a single plane whose orientation corresponds to that of the general plane of the watch movement. In the present application, the term “winding mass” means a mass having sufficient inertia to be able to fulfill its primary function which consists of being able to supply energy to the winding mechanism.

[0025] The circular translational movement of the winding mass 14 makes it possible to reduce the thickness of the watch movement compared to the existing circular translational automatic winding mechanisms mentioned above. This also makes it possible to optimize the winding of the barrel, in particular because this plane corresponds to that of the natural swing of the arm of a wearer of a wristwatch, when the latter moves while walking.

[0026] For this purpose, in view of figures 4a, 4b, the winding mass 14 comprises an armature 16 as well as two separate masses 18a, 18b, hereinafter referred to as weights, fixed to the armature 16 and together constituting an unbalance to optimize the initiation of the movement of the winding mass and therefore the winding of the barrel. The two weights 18a, 18b and the armature 16 may be in one piece according to a variant. The armature 16 has a substantially rectangular or square shape arranged around a central part of the watch movement 10 in order to make this central part visible through a transparent back of a watch case containing the movement. The transparent back may in particular be a sapphire crystal.

[0027] More particularly, the armature 16 comprises two fixing parts 16a, 16b arranged opposite each other and on either side of the central part of the watch movement as well as a first and a second support 16c, 16d on which the two weights 18a, 18b of the winding mass 14 are fixed. The two supports 16c, 16d preferably constitute, for the weights, support surfaces which extend opposite each other substantially perpendicular to the two fixing parts 16a, 16b. These each comprise two counterbores 17a, 17b at the orifice of two screw holes. Screws 22 are mounted in the screw holes with their end screwed into a hole in each rotating arm and their screw head countersunk in the counterbore 17 as shown in Figure 6. A bearing 23 is mounted between the screw body and the screw hole to ensure rotation of the armature 16 relative to the screws 22.

[0028] According to a non-illustrated embodiment, the winding mass may comprise three weights which are each arranged between two rotating arms which connect the armature to the frame of the watch movement. The armature may comprise for this purpose three fixing parts which are each connected to the frame by a rotating arm. These three fixing parts are arranged around a central part of the watch movement alternating with three supports on which the three weights are fixed. These can form a single piece with the three supports of the armature according to a variant. Although the shape of the armature is substantially rectangular according to the illustrated embodiment, it could have a substantially annular shape according to a variant.

[0029] According to another embodiment not illustrated, the winding mass may be free of unbalance. More particularly, the winding mass may consist of a block of uniform mass, for example in the form of a disc, and having a sufficient thickness to fulfill the function of winding mass. It is in fact the eccentric or offset movement, induced by the rotating arms, of the winding mass which gives it an unbalanced arrangement similar to an unbalance.

[0030] According to the example of Figure 7, three arms 30b, 30c, 30d of the four rotary arms can be mounted on simple pivots 32 while the fourth arm 30a is mounted on a transmission shaft according to the detailed description below. The four rotary arms are mounted on two bridges 12a, 12b (Figure 1) located on two opposite sides of the watch movement 10 so that these rotary arms are located close to the four corners of the watch movement as can be seen in Figure 3.

[0031] The axis of each pivot 32 extends perpendicular to the general plane of the watch movement so that the four rotating arms can pivot in a plane whose orientation is identical to the general plane of the watch movement in order to constrain the circular translation movements in this plane. Each rotary arm 30a, 30b, 30c, 30d is further arranged to be free to rotate through 360°, in particular in a plane located between the armature and the bridges 12a, 12b of the frame, in order to be able to impart to the winding mass 14 the sequence of the circular translation movement illustrated by figures 9a to 9d.

[0032] With reference to Figure 1, the height of the visible face of the two bridges 12a, 12b relative to the frame 12 corresponds substantially to the thickness of the two weights 18a, 18b of the winding mass 14 in order to form two hollow volumes arranged on either side of the central part of the movement. The two weights 18a, 18a can thus move inside these two volumes according to the circular translational movement of the winding mass 14.

[0033] The two weights 18a, 18b (figures 4a and 4b) each comprise an external face 19a intended to be mounted opposite a portion of the case middle of a watch case when the watch movement is mounted in the case, and an internal face 19b opposite the external face. The internal face 19b of at least one of the two weights 18a, 18b comprises a clearance 20 so that the winding mass 14 can partially and temporarily envelop a member of the watch movement without coming into contact with it, in particular one or more gear trains 11, when a circular translational movement is imparted to the winding mass 14.

[0034] Preferably, at least one of the weights 18a, 18b comprises a cutout 21 in order to form with the frame 12 an opening for the passage of a control stem, in particular a winding or time-setting stem 80.

[0035] With reference to Figures 6 to 8, the automatic winding mechanism further comprises transmission means for winding the barrel 60 according to the circular translational movement of the winding mass 14. For this purpose, a gear train is engaged with the ratchet 70 of the barrel 60 and comprises a transmission wheel 42 secured to a transmission shaft 41 mounted on two bearings 41a, 41b and on which the fourth rotary arm 30a is fixed. The transmission wheel 42 meshes with a conventional inverter 43 which comprises a first and a second clutch mobile 44, 45.

[0036] More particularly, the transmission wheel 42 is engaged with a clutch wheel 44a of the first clutch mobile 44. A clutch wheel 45a of the second clutch mobile 45 meshes with the clutch wheel 44a of the first mobile while the pinions 44b (only the pinion of the first clutch mobile is visible in FIG. 6) of the two clutch mobiles are engaged with a first mobile 46 of a reduction gear. The pinion of the first mobile 46 meshes with the wheel 47a of a second mobile 47 whose pinion 47b is engaged with the barrel ratchet 70 to actuate the rotation of the barrel shaft. The operation of this type of reverser is well known to those skilled in the art and will therefore not be written. It should be noted, however, that the first and second clutch mobiles can be of different types, for example ratchet, ball or spring.A wolf-toothed wheel 72 secured to the barrel shaft cooperates with a pawl 74 located at the end of a leaf spring 76.

[0037] According to another embodiment illustrated by figures 10a and 10b, the transmission means for winding the barrel according to the circular translational movement of the winding mass 14, comprise a traction lever 50, and a thrust lever 52. These two levers comprise at a first end a pawl 50a, 52a configured to respectively pull and push a tooth of the barrel ratchet 70 or a tooth of an intermediate wheel engaged with the ratchet according to a non-illustrated variant.

[0038] Two of the four rotating arms are connected to an actuable portion 50b, 52b located at a second end of the pull lever 50 and the push lever 52 by means of an axle 56 mounted through an opening 51, 53. This makes it possible to actuate the pull lever 50 and the push lever 52 so that their respective pawl 50a, 52a pulls and pushes a tooth of the barrel ratchet 70. The latter can thus be actuated in rotation in a single direction according to the circular translational movement of the winding mass 14.

[0039] The armature 16 of the winding mass 14 comprises on a lower face at least one elastic member 54 which in particular is for example in the form of two spring blades 54a, 54b arranged to act on the actuable part 50b, 52b of the traction lever 50 and of the thrust lever 52 to force their respective pawl 50a, 52a against the barrel ratchet 70.

[0040] The operation of these transmission means according to this second embodiment is similar to a Pellaton type system in which the eccentric is replaced by the two rotating arms. Reference list Watch movement 10 Cog 1 1 Building 12 First and second bridges 12a, 12b Winding weight 14 Frame 16 First and second fixing parts 16a, 16b 17 counterbores First and second mass supports 16c, 16d First weight 18a External face 19a Internal face 19b Clearance 20 Second weight 18b External face 19a Internal face 19b Cut 21 Screw 22 Level 23 Arms 30a, 30b, 30c, 30d Pivots 32 Means of transmission 40 Drive shaft 41 Levels 41 a, 41 b Transmission wheel 42 Inverter 43 First clutch mobile 44 Clutch wheel 44a I Pinion 44b first embodiment Second clutch mobile 45 45a clutch wheel First mobile 46 Second mobile 47 Wheel 47a Sprocket 47b 50 pull lever 50a ratchet Actionable part 50b Hole 51 Push lever 52 Ratchet 52a second embodiment Actionable part 52b Hole 53 Elastic organ 54 Leaf springs 54a, 54b Barrel 60 Rochet 70 Wolf Tooth Wheel 72 Ratchet 74 Leaf spring 76 80 time setting stem

Claims

Claims 1. A watch movement (10) comprising in particular a frame (12, 12a, 12b), gear trains (11), a barrel (60) and an automatic winding mechanism for winding the barrel (60), the winding mechanism comprising a winding mass (14) mounted articulated on the frame (12a, 12b) by means of rotating arms (30a, 30b, 30c, 30d) so that the winding mass (14) can perform a circular translational movement, the winding mechanism further comprising transmission means arranged to transmit the movement of the winding mass (14) to the barrel (60), characterized in that the winding mass (14) is connected to said rotating arms (30a, 30b, 30c, 30d) so as to constrain the circular translational movement of said mass (14) in a plane parallel to the general plane of the watch movement and in that said rotating arms (30a, 30b, 30c, 30d) are free to pivot through 360°.

2. Watch movement (10) according to claim 1, characterized in that it further comprises an armature (16) integral with the winding mass (14) or forming a single piece with said mass (14), and in that the rotary arms (30a, 30b, 30c, 30d) are pivotally connected to the armature (16), said rotary arms being arranged between said armature (16) and the frame (12a, 12b).

3. Watch movement according to claim 1 or 2, characterized in that the winding mass (14) comprises an unbalance (18a, 18b).

4. Watch movement according to claim 2, characterized in that the armature (16) comprises at least a first and a second fixing part (16a, 16b) on which the rotary arms are connected, and at least a first and a second support (16c, 16d) each supporting a weight (18a, 18b), said weights together forming the unbalance of the winding mass (14), said fixing parts (16a, 16b) and said supports (16c, 16d) each being arranged alternately on the armature (16) around a central part of the watch movement.

5. Watch movement according to the preceding claim, characterized in that the weights (18a, 18b) are arranged on a single face of the armature (16).

6. Watch movement according to claim 4 or 5, characterized in that said at least first and second fixing parts (16a, 16b) are each connected to the frame (12a, 12b) by two arms of said rotating arms.

7. Watch movement according to one of claims 4 to 6, characterized in that the weights (18a, 18b) each comprise an external face (19a) intended to be mounted opposite a portion of the middle of a watch case when the watch movement is mounted in said case, and an internal face (19b) opposite the external face, the internal face (19b) of at least one of the weights (18a, 18b) comprising a clearance (20) to be able to partially envelop at least one member of the watch movement, in particular a gear train (11), when a circular translational movement is imparted to the winding weight (14).

8. Clock movement according to one of claims 4 to 7, characterized in that at least one of the weights (18a, 18b) comprises a cutout (21) for the passage of a control stem such as a time-setting stem (80).

9. Watch movement according to one of the preceding claims, characterized in that the winding mass (14) is articulated on the frame (12a, 12b) by means of three or four rotating arms.

10. Watch movement according to one of the preceding claims, characterized in that the winding mass comprises three weights which are each arranged between two rotating arms.

11. Watch movement (10) according to one of the preceding claims, characterized in that the transmission means comprise a gear train engaged with the barrel ratchet (70), at least one of the rotary arms (30a, 30b, 30c, 30d) being integral with a transmission shaft (41) comprising a transmission wheel (42) engaged with the gear train and arranged to be driven in rotation by the rotation of said at least one rotary arm.

12. Watch movement (10) according to one of claims 1 to 10, characterized in that the transmission means comprise a pull lever (50), and a push lever (52), the pull and push levers (50, 52) comprising at a first end a pawl (50a, 52a) configured to respectively pull and push a tooth of the barrel ratchet (70) or of a wheel engaged with the barrel ratchet, alternately so that said ratchet (70) is actuated in rotation in a single direction, the pull and push levers (50, 52) each comprising a second end secured to one of said rotary arms (30a, 30b).

13. Watch movement (10) according to the preceding claim, characterized in that the winding mass (14) comprises at least one elastic member (54) acting on an actuable part (50b, 52b) of the traction lever (50) and of the push lever (52) to force their respective pawl (50a, 52a) against the barrel ratchet (70) or said wheel.

14. Timepiece comprising the watch movement according to one of the preceding claims.

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