EP3492995A1 - Crown system for a timepiece - Google Patents

Abstract

A crown system (1) for a timepiece, comprising: - a tube (3) arranged to be fixed in a middle part of a timepiece and comprising a thread (7) intended to be accessible from outside the said caseband: - a ring (11) comprising a skirt (13) provided with a thread (9) arranged to cooperate with said thread (7), and a tubular central portion (15) arranged to slide inside said tube (3); - a rod (21) intended to be in kinematic connection with a mechanism that includes said timepiece, one end (21a) of said rod (21) being located inside said tubular central portion; (15) - a clutch (23) arranged to move between a disengaged state, wherein said rod (21) and said ring gear (11) are disengaged from each other when said thread (7) cooperates with said tapping (9), and an engaged state in which said rod (21) and said ring (11) are integral in rotation when said ring gear (11) is pulled axially with respect to said tube (3). According to the invention, the system (1) further comprises a locking device (27) arranged to block any rotation of said rod (21) when said clutch (23) is in its disengaged state.

Description

Technical area

The present invention relates to the field of watchmaking. It relates, more particularly, a screw crown system for a timepiece.

State of the art

In order to adjust the indicating members and / or to reassemble the motor member of a timepiece, a ring is typically provided on the outer wall of the middle part of the piece. This ring is associated with a rod, which passes through a corresponding opening in the middle part of the part, to form a kinematic connection between the ring and a device for adjusting and / or reassembly of the movement which is located at inside the case. This opening represents a passage for the infiltration of moisture and dust inside the housing, and requires one or more seals to compensate for this defect.

In order to avoid that the crown is rotated unexpectedly and / or to improve the sealing of the part, it is known to provide an arrangement by which the crown can be screwed to the middle part. A classic example of this kind of crown system is illustrated in the document CH251701 . In this variant, a tube is fixed in the middle, this tube having a thread which is located outside the middle part. The skirt of the crown has a tapping complementary to the thread, which allows to screw the crown on the tube. In doing so, the user can immobilize the crown by screwing it on the tube, which, at the same time, compresses an O-ring seal to improve its resistance to the pressure of the water during an immersion. A clutch is also provided, arranged to ensure that the mechanism controlled by the crown is disengaged from the crown when the latter is screwed or unscrewed.

To control said mechanism, it is sufficient to unscrew the crown and then pull it outwards to bring the clutch into its engaged state, which makes the crown integral in rotation with the rod.

After adjustment and / or reassembly, the crown is pushed towards the middle part, thus disengaging the clutch, and is subsequently screwed on the tube.

However, depending on the quality of manufacture and the state of wear of the system, it is still possible that the rod is unwantedly rotated by friction generated when the user screws or unscrews the crown, which can lead to disruption the position of the indicating organs.

The object of the invention is therefore to provide a crown system for a timepiece in which the aforementioned defects are at least partially overcome.

Disclosure of the invention

More specifically, the invention relates to a crown system for a timepiece, comprising a tube arranged to be fixed in a middle part of a timepiece, for example by driving, gluing, crimping, welding, or screwing. , and which also comprises a thread intended to be located outside said middle part. The system further comprises a ring comprising a skirt provided with a tapping arranged to cooperate with said thread, a tubular central part arranged to be able to slide inside said tube, as well as a rod whose end is at interior of said tubular central portion. This rod is intended to be in kinematic connection with a mechanism that includes said timepiece, in a known manner. Furthermore, a clutch is arranged to selectively bind said rod and said ring in rotation according to the axial position of said ring, the clutch being in disengaged state at least when said threading and said tapping cooperate, and in engaged state when the ring is pulled axially outwards.

According to the invention, the system further comprises a locking device arranged to block any rotation of said rod when said clutch is disengaged. Note that it is not excluded that the locking device is also blocked in certain circumstances even if the clutch is in its engaged state (see an example below).

By these means, said rod is actively blocked in rotation against any inadvertent angular displacement during screwing and unscrewing of the crown on the tube. Any unintentional adjustment of the mechanism by friction is thus avoided.

Advantageously, said rod may have a first axial position, in which said locking device is active (that is to say in a configuration where all rotation of the rod is blocked), and at least a second axial position, in which said locking device is unlocked. By bringing the rod into its second axial position, the user can exercise active control over the moment when the rod can be rotated in order, for example, to adjust an indicating member or to refit a mainspring.

Advantageously, the ring has a first axial position, in which said clutch is disengaged and said locking device is locked, a second axial position in which said clutch is engaged and said locking device is blocked, and a third axial position in which said clutch is engaged and said locking device is unlocked. These three positions ensure that the adjustment of the function of the watch movement is done only under a voluntary action on the part of the user. Any inadvertent adjustment is thus prevented.

Advantageously, said locking device can be arranged to make said rod and said tube, which is fixed by definition relative to the middle part, integral in rotation when the rod is in its first axial position. Since the locking device acts to bind the tube and the rod and can thus be located entirely inside the tube, the system can be made compact.

Advantageously, the locking device may comprise a first locking element integral in rotation with said rod and a second locking element integral in rotation with said tube. These locking elements may be, for example, a non-circular shape (polygonal, star, crenellations, etc.), and a corresponding complementary opening, conventional teeth, or singing teeth. This last possibility is particularly advantageous, especially when the singing teeth have each of triangular profile teeth, since the engagement between the teeth is thus facilitated when the crown is pushed back after use.

In another variant, the two locking elements each have a friction surface arranged to cooperate with each other so as to form a friction locking device arranged to block any relative rotation between the rod and the tube when (de) screwing the crown. No teeth are necessary for this lock, which promotes simple manufacture.

Advantageously, said second locking element can be carried by a ring attached to the tube, for example by driving, crimping, gluing, welding or the like. Simple and economical construction and assembly are possible.

Advantageously, said rod may comprise, at one of its ends, a shoulder arranged to cooperate with a ring fixed in said tubular central portion to axially move said rod. Once again, simple and economical construction and assembly are possible.

Advantageously, a first seal may be provided at the bottom of a groove separating said skirt and said tubular central portion, and a second seal may be provided between said tube and said tubular central portion. The tightness of the system is thus ensured independently of the axial position of the crown.

Advantageously, an elastic element may be housed in a bore formed between the bottom of said tubular central portion and the end of the rod, to ensure that said clutch engages positively when the ring is unscrewed from the tube.

Advantageously, the elastic element is a helical spring, which can also house a spring guide. The latter may include a flange against which the spring rests, and a boss arranged to abut against the end of the rod. The hump can ideally be rounded or pointed, and its point of contact with the rod is preferably on the axis of rotation of the rod. Alternatively, the hump can be on the end of the rod and lean against the spring guide, or a ball may be interposed between these two elements. In doing so, the transmission of parasitic couples between the crown and the rod during (de) screwing of the crown is minimized since the friction and their lever arm are minimized at the interface between the spring and the rod.

Finally, the invention relates to a timepiece comprising a crown system as defined above.

Brief description of the drawings

• Fig. 1 est une vue en coupe partielle d'un système de couronne selon l'invention, dans laquelle la couronne est dans une première position axiale, vissée sur le tube ;
• Fig. 2 est une vue similaire à la fig. 1, dans laquelle la couronne est dans une deuxième position axiale, dévissée mais pas tirée ;
• Fig. 3 est une vue similaire à la fig. 1, dans laquelle la couronne est dans une troisième position axiale, dévissée et tirée ;
• Fig. 4 est une vue semblable à la fig. 1, mais d'un deuxième mode de réalisation ;
• Fig. 5 est une vue semblable à la fig. 2, mais du deuxième mode de réalisation ; et
• Fig. 6 est une vue semblable à la fig. 3, mais du deuxième mode de réalisation.

Other details of the invention will appear more clearly on reading the description which follows, given with reference to the appended drawings in which:

• Fig. 1 is a partial sectional view of a crown system according to the invention, wherein the ring is in a first axial position, screwed onto the tube;
• Fig. 2 is a view similar to the Fig. 1 in which the ring is in a second axial position, unscrewed but not pulled;
• Fig. 3 is a view similar to the Fig. 1 in which the ring is in a third axial position, unscrewed and pulled;
• Fig. 4 is a view similar to the Fig. 1 but of a second embodiment;
• Fig. 5 is a view similar to the Fig. 2 but of the second embodiment; and
• Fig. 6 is a view similar to the Fig. 3 but of the second embodiment.

Embodiment of the invention

The Figures 1 to 3 represent a first embodiment of a crown system 1 according to the invention in partial section (left in the figures), and in section (right). The figure 1 illustrates said system 1 in a first state, screwed crown, the figure 2 in a second state, unscrewed crown but not removed, and the figure 3 corresponds to a third state, screwed crown and pulled outwards.

The system 1 comprises a tube 3, intended to be fixed in a passage provided in the wall of a middle part of a timepiece (not shown). To this end, the tube 3 comprises a threaded zone 5, arranged to cooperate with a complementary tapping provided in said passage. Alternatively, the tube 3 may have a smooth outer surface, so that the tube 3 can be driven, crimped, glued or welded in said passage.

The tube 3 is also provided with a thread 7 which, when the tube 3 is fixed to the middle part, is located outside the latter. It should be noted that the tube 3 may protrude from the outer surface of the middle part, or alternatively into a recess thereof.

This thread 7 cooperates with a tapping 9 that includes the crown 11. As in the document CH251701 mentioned above, the ring 11 comprises a skirt 13 surrounding a tubular central portion 15, an annular groove 16 lying between them. This annular groove 16 is shaped to surround the end of the tube 3 when the ring 11 is screwed into it. At the bottom of the groove 16 is a first seal 17, which is compressed between the ring 11 and the front face of the tube 3 when the system 1 is in the state of the figure 1 . The tubular central portion 15 may be integral with the ring 11, or may be an insert on the latter by driving, gluing, welding or the like.

The tubular central portion 15 of the ring 13 is adjusted to slide inside the tube 3, a second seal 19 being in a corresponding groove 20 formed in the inner wall of said tube, thereby sealing between the tubular central portion 15 and the inner wall of the tube 3 when the ring 11 is unscrewed.

The system 1 also comprises a rod 21 intended to be kinematically connected to a device for reassembly and / or adjustment of a function of a clockwork movement (not shown) by means of an additional tapping 21b or by any other appropriate means, in a known manner. This rod 21 is coaxial with the tube 3 and the tubular central portion 15 of the ring 11, and extends so that its end 21a takes place within the tubular central portion 15 slidably. This end 21a defines a shoulder 21c, whose function will appear more clearly below.

A clutch 23, which serves to selectively couple the ring 11 and the rod 21 in rotation, is provided between the tubular central portion 15 and the rod 21. Said clutch 23 is constituted firstly by a portion of rod located in the inside the tubular central portion 15, and which has a non-circular cross section 23a, and secondly by a correspondingly shaped opening provided in a ring 23b fixed in the free end of the tubular central portion 15 by gluing, welding, crimping, driving, or by any suitable method. Alternatively, the ring 23b can be integral with the tubular central portion 15, especially in the case where the latter is a separate piece attached to the crown 11. Said non-circular portion 21a and the opening may each have a shape polygonal (eg square), star, crenate, or the like. Alternatively, this clutch 23 may consist of edge teeth provided on the rod 21 and the ring 23b, or any other suitable means.

It should be noted that the opening provided in the ring 23b has a smaller diameter than that of the shoulder 21c so that the ring 23b can bear on the latter to allow a pull of the rod 21 to the outside.

The tubular central portion 15 also houses an elastic element 25 in the bore formed between its bottom and the end of the rod 21. In the illustrated embodiment, this elastic element 25 is a coil spring, but other shapes elastic elements are possible, such as an elastomer element.

This elastic member 25 serves to exert a force on the ring gear 11 so that the clutch 23 is kept in the engaged state (see FIG. Figures 2 and 3 ) when the ring 11 is not screwed on the tube 3, as will be described below. The force exerted by the elastic element 25 on the ring 11 also serves to return the rod 21 to its initial position when the ring 11 is screwed onto the tube 3.

The system 1 also comprises a locking device 27, comprising a first locking element 27a integral in rotation with the rod 21, as well as a second locking element 27b integral in rotation with the tube 3. The second locking element 27b being rotationally integral with said tube 3, which is in turn fixed to the middle part of the timepiece, the rod 21 is locked in rotation when the locking device 27 is active, and can not rotate unexpectedly. In the illustrated version, the locking elements 27a, 27b are formed by triangular shaped edge teeth. The toothing constituting the second locking element 27b is provided on a ring 29 surrounding the rod 21 and fixed in a corresponding seat formed in the inner end of the tube 3. This attachment can be performed for example by gluing, welding, driving, crimping or similar.

Said first toothing 27a is positioned on the rod 21 so that it meshes with the second toothing 27b when the ring 11 is screwed onto the tube (cf. figure 1 ), and is out of range of the second toothing 27b when the ring 11 is unscrewed and pulled outwards (see figure 3 ). The elastic element 25 exerts sufficient force on the end 21a of the rod 21 to hold the teeth 27a, 27b in engagement with each other when the ring 11 is being screwed or unscrewed, which prevents any inadvertent pivoting of the rod 21 because of friction between the latter and the ring 1.

Alternatively, the teeth 27a, 27b may be conventional edge teeth, or may be replaced respectively by a portion of the rod 21 of non-circular section and a corresponding opening in the ring 29, similarly to the clutch 23 above.

In the version shown, the system 1 as such has no means to prevent the entire crown 11 - rod 21 can be removed completely from the tube 3, which simplifies assembly. Indeed, the tube assembly 3 - ring 29 can be attached to a middle part, and then the entire crown 11 - rod 21 can be inserted. Subsequently, the rod 21 can be coupled to the movement, the latter having an arrangement to prevent the complete removal of the rod 21 and thus the ring 11 in a known manner.

However, if desired, it is possible to provide additional means to prevent the removal of the crown, such as a circlip or a pin projecting from the rod 21.

The operation of system 1 will now be described in connection with the sequence of Figures 1 to 3 .

In the figure 1 , the ring 11 is in its first axial position, screwed onto the tube 3. The clutch 23 is disengaged, and the ring 11 is not kinematically connected to the rod 21. The rod 21 is in its first axial position, so that the locking device 27 is engaged, the rod 21 thus being integral in rotation with the fixed tube 3 and prevented from rotating.

In order to control a function of the movement, such as a setting of an indicating member or to reassemble a mainspring, the user unscrews the ring 11 of the tube 3. In doing so, the clutch 23 remains disengaged, and the central tubular portion 15 slides on the end of the rod 21. The ring 11 can be unscrewed, without influencing the position of the rod 21. In doing so, the locking device ensures that the rod 21 remains secured in rotation of the fixed tube 3, and thus prevents inadvertent entrainment of said rod 21 by friction generated between the ring 11 and the rod 21. Such friction is generated in particular, but not exclusively, by the support of the elastic member 25 on the end 21a of the rod 21.

When the ring 11 is unscrewed, the elastic member 25 is free to move the latter relative to the rod 21 so that the clutch 23 is engaged. In doing so, the ring 11 is brought into kinematic connection with the rod 21. However, the latter remains in its first axial position, and the locking device 27 remains blocked. The ring 11, which is now in its second axial position, can not yet be rotated. This state is illustrated on the figure 2 .

If the user pulls the crown now outwards (that is to say upwards according to the orientation of the figures) so that the ring 11 adopts its third axial position, the ring 23b bears on the shoulder 21c of the end 21a of the rod 21, thus moving the latter axially in its second axial position. The first toothing 27a is thus moved out of reach of the second toothing 27b, which unlocks the device of locking. We thus arrive at the state illustrated on the figure 3 . It is also possible to provide several additional axial positions to control several mechanisms of the watch movement.

Since the locking device 27 is neutralized, the ring 11 can be turned, this rotation being transmitted to the clockwork movement via the rod 21.

When the user has completed the adjustment and / or reassembly, he pushes the crown 11 towards the tube 3, the elastic element 25 helping to push the rod 21 towards the middle part, so that the locking device 27 hangs again. The system components are thus again in the positions illustrated on the figure 2 , that is to say that the ring 11 is in its second axial position, and the rod 21 is in its first axial position.

By pushing the ring 11 now towards the tube 3, the clutch 23 disengages, and the user can thus screw the ring 11 on the tube 3. It thus returns to the situation illustrated on the figure 1 , the ring 11 and the rod 21 each adopting its first axial position.

The Figures 4 to 6 illustrate a second embodiment of a crown system 1 according to the invention, the states of the system shown in these figures respectively corresponding to those of the Figures 1 to 3 . In order to avoid overloading these figures, only the reference signs mentioned later are reproduced.

The variant of Figures 4 to 6 differs from that of Figures 1 to 3 in two main ways. First, the locking device 27 is frictional, and secondly, the transmission of force between the elastic member 25 and the end of the rod 21 has been changed.

Regarding the locking device 27, the latter comprises, instead of teeth, a first friction surface 27c which has a flat face of a shoulder 21d integral with the rod 21. This first friction surface 27c is opposite a second friction surface 27d which is integral with the tube 3. In the variant shown, the second friction surface 27d is formed on a planar inner face located at the bottom of the tube 3, but may also be provided on an additional piece reported on the tube 3 similarly to the second toothing of the variant of Figures 1 to 3 . Furthermore, the friction surfaces 27c, 27d are not necessarily flat and may be frustoconical, for example.

In doing so, the two friction surfaces 27c, 27d respectively constitute first and second locking elements, the restoring force applied by the elastic element 25 serving to maintain these two surfaces in positive contact, without slipping, against the friction generated during (de) screwing of the crown 11.

The friction surfaces 27c, 27d can be treated so as to increase the generated friction. For this purpose, it is possible to provide, for example, layers of high-roughness material such as layers comprising diamond powder, corundum or the like, patterns machined in their surfaces, microgranulated surfaces or the like.

In order to minimize the friction generated during the (de) screwing of the crown, the elastic element 25 does not rest directly on the end 21a of the rod 21. Sometimes, its end can be relatively sharp, which risks to increase said friction. For this purpose, a tubular spring guide 31 is housed inside the elastic element 25. This spring guide has at its inner end (that is to say the one closest to the rod 21) a flange 25a against which the resilient element 25 is supported. Adjacent to this rim 31a is a bump 31b of convex section, which bears against the end 21a of the rod 21 at a single point, substantially on its axis of rotation. The return force exerted by the spring 25 is thus transmitted to the rod 21 via the spring guide 31. The boss 31b may alternatively be pointed, and may alternatively be on the end 21a of the rod and press against the spring guide 31. Again alternatively, a ball may be interposed between the end 21a of the rod 21 and the spring guide 31 for the same purpose.

This arrangement substantially reduces the torque transmission by friction between the ring 11 and the rod 21 with respect to the variant of the Figures 1 to 3 , since the contact surface with the rod 21 as well as the lever arm of the torque that the elastic member 25 can exert on the rod 21 are minimized. Since the friction surfaces 27c, 27d are plated one to against the other under the effect of the spring 25 and have a contact zone which is of substantially greater extent than that between the boss 31b and the end 21a of the rod, it is impossible for the rod 21 can be rotated untimely. Indeed, the resistance torque generated by the friction between the surfaces 27c and 27d is necessarily substantially greater than that which can be applied between the boss 31b and the rod 21 when (de) screwing the ring 11, the normal force being substantially the same for both contact areas but the areas of the contact areas being different.

Although the invention has been particularly shown and described with reference to particular embodiments, other variants are possible without departing from the scope of the invention as defined in the claims.

Claims (16)

A crown system (1) for a timepiece, comprising: a tube (3) arranged to be fixed in a middle part of a timepiece and comprising a thread (7) intended to be accessible from outside said middle part; - A ring (11) comprising a skirt (13) provided with a thread (9) arranged to cooperate with said thread (7), and a tubular central portion (15) arranged to slide inside said tube (3). ); - A rod (21) intended to be in kinematic connection with a mechanism that includes said timepiece, an end (21a) of said rod (21) located within said tubular central portion (15); a clutch (23) arranged to move between a disengaged state, in which said rod (21) and said ring gear (11) are disengaged from one another when said threading (7) cooperates with said tapping (9), and an engaged state in which said rod (21) and said ring gear (11) are integral in rotation when said ring gear (11) is pulled axially with respect to said tube (3); characterized in that the system (1) further comprises a locking device (27) arranged to block any rotation of said rod (21) when said clutch (23) is in its disengaged state. System (1) according to claim 1, wherein said rod (1) has a first axial position, wherein said locking device (27) is active, and at least a second axial position, wherein said locking device (27) ) is neutralized. System (1) according to claim 2, wherein said ring gear (11) has a first axial position, in which said clutch (23) is disengaged and said locking device (27) is active, a second axial position in which said clutch (23) is engaged and said locking device is active, and a third axial position in which said clutch is engaged and said locking device is neutralized. System (1) according to one of claims 2 and 3, wherein said locking device (27) is arranged to make said rod (21) and said tube (3) integral in rotation when said rod (21) is in its first axial position. System (1) according to claim 4, wherein said locking device (27) comprises a first locking element (27a; 27c) integral in rotation with said rod (21) and a second locking element (27b; 27d). integral in rotation with said tube (3). System (1) according to claim 5, wherein said first locking element (27a) as well as said second locking element (27b) each comprise a toothing. System (1) according to claim 6, wherein said edge teeth each comprise teeth of triangular profile. System (1) according to one of claims 5-7, wherein said first locking element (27c) as well as said second locking element (27d) each comprise a friction surface arranged to cooperate with each other . System (1) according to one of claims 5-8, wherein said second locking member (27b) is carried by a ring (29) fixed to said tube (3). System (1) according to one of the preceding claims, wherein said rod (21) comprises, at one of its ends (21a), a shoulder (21c) arranged to cooperate with a ring (23b) fixed in said part tubular central (15) for axially displacing said rod (21). System (1) according to one of the preceding claims, wherein a first seal (17) is provided at the bottom of a groove (16) separating said skirt (13) and said tubular central portion (15), and a second seal (19) is provided between said tube (3) and said tubular core (15). System (1) according to one of the preceding claims, further comprising a resilient element (25) housed in a bore formed between the bottom of said tubular central portion (15) and the end (21a) of said rod (21) . System (1) according to the preceding claim, wherein said elastic element (25) is a helical spring. System (1) according to the preceding claim, further comprising a spring guide (31) housed at least partially in said elastic element (25), said spring guide (31) comprising a flange (31a) on which said spring resilient element (25), one of said spring guide (31) and the end (21a) of said rod (21) further comprising a boss arranged to abut the other of said spring guide ( 31) and the end (21a) of said rod (21). System (1) according to claim 13, further comprising a spring guide (31) housed at least partially in said elastic member (25), said spring guide (31) comprising a flange (31a) on which said spring elastic element (25), a ball being interposed between said spring guide (31) and the end (21a) of said rod (21) Timepiece comprising a system (1) according to one of the preceding claims.

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