Timepiece component to be attached to a shaft and its assembly process

Abstract

The invention relates to a watch component (1) selected from a toothed wheel, a display disc, and a cam comprising a passage (2) for receiving a shaft (10). The component (1) according to the invention includes a retaining element (6) and a locking arm (4) capable of moving between a rest position and a locked position in which it cooperates with said retaining element (6). During its movement from its rest position to its locked position, said locking arm (4) is designed to clamp the shaft (10) against the wall (3) of the passage (2) so as to secure it to said watch component and, once in its locked position, to maintain it in a clamped configuration. The invention also relates to a watch assembly comprising such a watch component (1) and a shaft (10) passing through said passage, said component and said shaft (10) being fixed to each other both axially and rotationally.The invention also relates to a method of assembling such a watch component (1) with a shaft (10) and a watch part comprising a watch assembly according to the invention.

Description

[0001] The present invention relates to a watch component chosen from a toothed wheel, a display disc (or indicator disc) and a cam, more precisely the fixing of such a watch component on a shaft. It also relates to a watch assembly comprising such a watch component fixed on a shaft, a watch device comprising such a watch assembly and at least one other watch component and a method of assembling such a watch component with a shaft.

[0002] Gear wheels or display discs are usually fixed to their shaft by traditional driving, that is, by plastic deformation of their opening. Alternatively, they can be fixed to their axis by gluing, riveting or brazing. These types of assemblies have the disadvantage of being irreversible.

[0003] European patent application EP 1 708 045 describes an alternative method for fixing a watch wheel to an axle using an elastic type of driving. The wheel described in this patent application has a circular central hole whose inner surface is bordered by elastic arms undergoing only elastic deformation when the axle is driven into the hole. This type of structure is not fully satisfactory because it only provides a weak hold. Devices for fixing watch components together, in particular a wheel on its axle, in which an intermediate piece is used for this purpose, as in document EP2743782, are also known. Other documents such as EP2977829 disclose devices for braking a wheel, the wheel comprising an elastic arm arranged to cooperate with notches in said wheel making it possible to adjust a clearance necessary for braking.

[0004] An aim of the present invention is to propose a watch component chosen from a toothed wheel, a display disc and a cam, intended to be fixed on a shaft so as to be integral in rotation and in translation with this shaft during its operation in a watch, said component at least partially overcoming the aforementioned drawbacks.

[0005] To this end, the present invention relates to a watch component chosen from a toothed wheel, a display disc and a cam comprising a passage intended to receive a shaft.

[0006] According to the invention, the watch component comprises a retaining element and a locking arm capable of moving between a rest position and a locked position in which it cooperates with said retaining element. When moving from its rest position to its locked position, the locking arm is intended to clamp the arbor against the wall of said passage so as to make it integral with said watch component and, once in its locked position, to maintain it in this state. Such a locking arm makes it possible to obtain a strong clamping force and therefore a good hold while retaining the possibility of detaching the watch component from the arbor.

[0007] The locking arm of the component according to the invention is intended to clamp the shaft against the wall of said passage either directly by pressing on the shaft, or indirectly by pressing on the wall of the passage intended to receive the shaft.

[0008] Advantageously, the passage is cylindrical. It is typically central.

[0009] According to a particular embodiment of the invention, the wall of said passage is configured to deform elastically in a plane perpendicular to the axis of the passage, and the locking arm is arranged so that, when it moves from its rest position to its locked position, it tightens said passage and, once in its locked position, it maintains it in a tightened configuration.

[0010] When moving from its rest position to its locked position, the locking arm typically presses on a portion, typically a bulge, of the outer surface of said wall.

[0011] Alternatively, when moving from its rest position to its locked position, the locking arm is intended to press directly on the shaft to clamp it against said wall.

[0012] The locking arm according to the invention is typically an elastic arm but it can also be a rigid arm articulated, typically by means of a pivot. Advantageously, this arm is arched. It typically extends substantially concentrically to the inner surface of the passage.

[0013] In the context of the present invention, the term "shaft" designates either a shaft itself or a barrel. Generally speaking, this term designates any cylindrical or truncated cone-shaped part or piece, solid or hollow, intended to pivot in a watch movement.

[0014] The watch component according to the invention is configured so that: depending on the dimensions, typically the diameter, of the shaft to which it is assembled, the insertion of the shaft into the passage: elastically deforms the wall of this passage so that it exerts an elastic restoring force on the shaft ensuring its axial and rotational retention with a relatively low translational holding force and rotational holding torque; or does not deform the wall of this passage.

[0015] The person skilled in the art will obviously choose the shaft to be assembled to the component according to the invention with dimensions such that the locking of the locking arm will make it possible to secure said component and said shaft, both in rotation and in translation during its operation in a timepiece.

[0016] The fact that, prior to locking the arm, the clamping force exerted on the shaft is low or zero has the advantage of allowing the adjustment of the relative position of the shaft with respect to the watch component according to the invention, angularly and / or axially, typically for their indexing, before locking their relative position by means of the locking arm. Having a low clamping force compared to a zero force before locking the locking arm allows for more precise adjustment. This also makes it possible to avoid the disturbance of the relative position of the shaft with respect to the watch component to which it is fixed at the time of locking the locking arm.

[0017] The invention also relates to a timepiece assembly comprising such a timepiece component and a shaft passing through said cylindrical passage, said component and said shaft being integral with each other both axially and in rotation. Preferably, the shaft of the assembly according to the invention is a barrel of a toothed wheel; its timepiece component is typically a display disc. In the timepiece assembly according to the invention, the locking arm is considered in the locked position.

[0018] A watchmaking device according to the invention comprises such a watchmaking assembly and at least one other watchmaking component crossed by said shaft in which the watchmaking component of said assembly ensures the axial maintenance of said at least one other watchmaking component on the shaft.

[0019] Finally, the invention relates to a method of assembling a watch component according to the invention with a shaft characterized in that it comprises the following steps: a. providing such a component and a shaft; b. positioning the shaft and said component so that the shaft is in the axis of said passage; c. moving one of the shaft or the component along said axis until the shaft is in said passage; d. moving the locking arm of the component from its rest position to its locked position.

[0020] This method typically comprises an additional step c' between steps c and d consisting of adjusting the relative position of the shaft with respect to the component by pivoting and / or sliding around and / or along said axis.

[0021] The invention also relates to a timepiece such as a wristwatch or a pocket watch comprising such a timepiece assembly.

[0022] Other characteristics and advantages of the present invention will appear on reading the following detailed description made with reference to the appended drawings in which: THE figures 1a et 1b represent, in top view, a display disk according to a first embodiment of the invention respectively in a rest position and in a locked position; the figures 2a et 2b represent, in top view, a part of a date display device comprising in particular a first display disc according to the first embodiment of the invention, such as that illustrated in figures 1a et 1b , mounted on the barrel of a pinion; the figures 3a et 3b are sectional views of the device illustrated respectively in figures 2a et 2b , along axis II; the figures 4a et 4b represent in top view, a part of a date display device comprising in particular a first display disc according to a second embodiment of the invention mounted on the barrel of a pinion.

[0023] THE figures 1a et 1b illustrate a display disc 1 according to a first embodiment of the invention. It typically carries a graduation (not shown) corresponding to the tens digits of a date display and is intended to be mounted on a shaft.

[0024] The display disc 1 comprises a central and cylindrical passage 2 of axis A, intended to receive said shaft. The wall 3 delimiting the cylindrical passage 2 is configured to be able to deform elastically in a plane perpendicular to the axis A while receiving the shaft and to be able to then exert an elastic clamping force on the shaft. This elastic deformation takes place over at least part of the circumference of said wall 3.

[0025] The display disc 1 further comprises a locking arm 4 and a retaining element 6. The locking arm 4 is able to move between a first position called the “rest position”, illustrated in figure 1a , and a second position called the “locked position,” shown in figure 1b , in which a hook 5 which it carries at its free end cooperates with the retaining element 6.

[0026] When moving from its rest position to its locked position, the locking arm 4 tightens the cylindrical passage 2 by pressure on the outer surface of its wall 3, in particular on a bulge 8 which it comprises. It tends to reduce the diameter of the cylindrical passage 2.

[0027] The section of the inner surface of the cylindrical passage 2 is C-shaped, it typically comprises two ends 3a and 3b intended to approach each other when locking the locking arm 4 to tighten the cylindrical passage 2. With reference to the figure 1a , when the locking arm 4 is in the rest position, the inner wall of the cylindrical passage 2 defines an arc of a circle with an angle α of approximately 340°. The inner surface of the cylindrical passage 2 may be smooth as shown in the figures or include hollows or bumps. In the illustrated case, in which the inner surface of the cylindrical passage 2 comprises a single arc of a circle, the angle α over which this arc of a circle extends is typically greater than 270°, preferably greater than 300°, more preferably greater than 330°.

[0028] Once in its locked position, the locking arm 4 holds the cylindrical passage 2 in a tightened configuration, as shown in figure 1b .

[0029] The locking arm 4 is a resilient arm. Alternatively, it could be rigid and articulated, typically by means of a pivot. This arm 4 is arched and extends concentrically to the inner surface of the cylindrical passage 2.

[0030] The locking arm 4 comprises, near its free end, a hole 7 intended to receive a tool facilitating the watchmaker's assembly operations.

[0031] THE figures 2a à 3b illustrate a part of a date display device 100 comprising a first display disc such as display disc 1, a toothed pinion 9 comprising a barrel 10 and a toothed wheel 11 whose barrel 12 is integral in rotation with a second display disc 13. The second display disc 13 typically carries a graduation (not shown) corresponding to the digits of the units of a date display. The barrel 12 comprises a cylindrical through-bore crossed by the barrel 10 of the toothed pinion 9. The barrel 10 is intended to pivot inside said bore.

[0032] In the figures 2a And 3a , the locking arm 4 of the first display disc 1 is in the rest position.

[0033] The device 100 is typically mounted as follows: the second display disc 13 is mounted on the barrel 12 of the toothed wheel 11 and secured to the latter. The barrel 10 is then inserted into the cylindrical bore passing through the toothed wheel 11 and then the first display disc 1 is mounted on the barrel 10. For this, its cylindrical passage 2 is aligned with the axis A of the barrel 10, then it is moved along this axis until the barrel 10 passes through the cylindrical passage 2. The wall 3 of the cylindrical passage 2 deforms elastically to allow the barrel 10 to pass. In this position, illustrated in figures 2a And 3a, the display disc 1 and the barrel 10 are fixed relative to each other. The elastic restoring force exerted by the wall 3 on the barrel 10 is however sufficiently weak so that the watchmaker can separate them in order to position them as desired (indexing in particular). Once the positioning has been achieved, the watchmaker typically inserts a tool into the hole 7 in order to lock the locking arm 4 by pulling the hook 5 behind the retaining element 6. The device thus obtained is illustrated in figures 2b And 3b In this device, the first display disc 1 and the pinion 9 form a set of two parts fixed relative to each other axially and in rotation and capable of remaining so during its use in a watch mechanism.

[0034] The first display disc 1 here plays the role of axially holding the display disc 13 and the unit wheel 11.

[0035] Alternatively, the device 100 could comprise a barrel 10 whose diameter to be inserted into the cylindrical passage 2 would be slightly smaller so that the wall 3 would not undergo any elastic deformation when the barrel 10 is inserted into the cylindrical passage 2. The barrel 10 would then be free to rotate and translate until the arm 4 is brought into the locking position.

[0036] As illustrated in figures 3a et 3b , the outer contour of the barrel 10 can advantageously comprise an inclined plane 14 to reinforce the axial retention of the first display disc 1 on the barrel 10.

[0037] In the example illustrated, the watchmaker who would like to separate the display disc 1 from the barrel 10 would only have to unlock the locking arm 4 by separating its hook 5 from the retaining element 6 and then exert a force along the axis A on the disc 1 or on the pinion 9 (or its barrel 10) to remove the barrel 10 from the cylindrical passage 2. The cylindrical passage 2 would then resume a configuration identical to that preceding its assembly with the pinion 9. It is said that the attachment of the disc 1 to the barrel 10 is reversible.

[0038] THE figures 4a et 4billustrate a part of a display device 200 comprising a first display disc 201 according to a second embodiment of the invention mounted on the barrel 210 of a pinion. Like the display disc 1, the display disc 201 comprises a central passage intended to receive the barrel 210. The members or parts of members bearing the references 201, 203, 204, 205, 206, 207, 210 correspond respectively to the members or parts of members bearing the references 1, 3, 4, 5, 6, 7, 10 of the device according to the first embodiment of the invention.

[0039] The display disc 201 differs from the display disc 1 according to the first embodiment of the invention in that its locking arm 204 is intended to act directly on the shaft 210 during locking. The inner central passage surface comprises two circular arcs, one of which is carried by the locking arm 204. The locking arm 204 in fact comprises a part 204a intended to bear against the shaft 210 when it passes from its rest position to its locked position.

[0040] A display disc (not shown) according to a third embodiment of the invention, differs from the disc according to the second embodiment of the invention in that the inner surface of its central passage is delimited by at least a first wall, the rigid inner contour of which is fixed relative to the body of the disc and intended to be in contact with the shaft when the locking arm is in the locked position and at least a second wall part, similar to the single wall according to the first embodiment of the invention, capable of deforming elastically and intended to be tightened against the shaft to fix it axially and in rotation relative to the disc when the locking arm is locked, and to be maintained in this tightened configuration by the locking arm when the latter is in the locked position.

[0041] Regardless of the embodiment considered, the passage intended to receive the shaft is typically part of a recess in which the locking arm is also located.

[0042] The watch component according to the present invention has many advantages over those of the prior art. It has a structure allowing it to be easily and securely fixed to a shaft. It is designed so that the adjustment of its relative position with respect to the shaft is as simple and precise as possible. It also allows reversible fixing.

[0043] It will be clear to those skilled in the art that the present invention is in no way limited to the embodiments presented above and illustrated in the figures. It is for example very well conceivable to produce a watch component according to the invention other than a display disc, for example a toothed wheel or a cam. In the case where the watch component according to the invention is a display disc or a toothed wheel, its passage intended to receive the shaft is preferably centered.

[0044] In variants, it is obvious that the shape of the organs, in particular the shape of the wall 3 bordering the cylindrical passage 2 or that of the locking arm 4 can vary infinitely as long as their functions are ensured.

Claims

1. Timepiece component (1) selected from a toothed wheel, a display disc and a cam, said timepiece component (1) comprising a passage (2) intended to receive an arbor (10), and being characterised in that it comprises a retaining element (6) and a locking arm (4) able to move between a rest position and a locked position in which it cooperates with said retaining element (6), and in that, during its movement from its rest position to its locked position, the locking arm (4) is intended to clamp the arbor (10) against the wall (3) of said passage (2) so as to fixedly attach it to said timepiece component (1) and, once in its locked position, to keep it in this state.

2. Timepiece component (1) as claimed in claim 1, characterised in that the passage (2) is cylindrical.

3. Timepiece component (1) as claimed in claim 1 or 2, characterised in that its wall (3) is configured to deform elastically in a plane perpendicular to the axis (A) of the passage (2), and in that its locking arm (4) is configured so that, during its movement from its rest position to its locked position, it narrows said passage (2) and, once in its locked position, it keeps it in a narrowed configuration.

4. Timepiece component (1) as claimed in any one of claims 1 to 3, characterised in that, during its passage from its rest position to its locked position, the locking arm (4) presses against a part of the outer surface of said wall (3).

5. Timepiece component (1) as claimed in claim 4, characterised in that said part of the outer surface of the wall (3) comprises a bulge (8).

6. Timepiece component (1) as claimed in claim 1 or 2, characterised in that, during its movement from its rest position to its locked position, the locking arm (4) is intended to press directly on the arbor (10) in order to clamp it against the wall (3).

7. Timepiece assembly comprising a timepiece component (1) as claimed in one of claims 1 to 6 and an arbor (10) passing through said passage (2), said component (1) and said arbor (10) being fixedly attached to each other both axially and in rotation.

8. Assembly as claimed in claim 7, characterised in that said arbor is a pipe (10) of a toothed wheel and in that said timepiece component is a display disc (1).

9. Timepiece device (100) characterised in that it comprises an assembly as claimed in claim 7 or 8 and at least one other timepiece component traversed by said arbor, the timepiece component (1) of said timepiece assembly ensuring that said at least one other timepiece component is held axially on said arbor (10).

10. Method of assembling a timepiece component (1) as claimed in one of claims 1 to 6 with an arbor (10), characterised in that it comprises the following steps: a. procuring a timepiece component (1) as claimed in one of claims 1 to 6 and an arbor (10); b. positioning the arbor (10) and the timepiece component (1) so that the arbor (10) is on the axis (A) of the passage (2); c. moving one of the arbor (10) or the timepiece component (1) along said axis (A) until the arbor (10) is located in the passage (2); d. moving the locking arm (4) of the timepiece component (1) from its rest position to its locked position.

11. Assembly method as claimed in claim 10, characterised in that it comprises an additional step c' between the steps c and d consisting of adjusting the relative position of the arbor (10) with respect to the timepiece component (1) by pivoting and / or sliding around and / or along the axis (A) of the passage (2).

12. Timepiece such as a wristwatch or pocket watch, characterised in that it comprises a timepiece assembly as claimed in claim 7 or 8.

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