EP1701225A1 - Screwed crown for a timepiece - Google Patents

Abstract

The crown has a head (8) with a tubular central part surrounded by a lateral skirt (12), and a case with an end surface carrying a design. The head has a truncated surface portion that co-operates with a truncated surface portion of a wall of the case. An elastic annular insert enables integration of the case on the head by wedging the portions and the disintegration of the case to allow the case to turn freely with respect to the head.

Description

The present invention relates to screw crowns or screwed crowns for timepieces and more particularly to such crowns having a pattern or a logo on their end face and in which said pattern can be oriented at will.

Screwed crowns are commonly used to equip watches in order to improve the sealing of these at their winding or control rod. This type of crown has the particularity of being able to take a unscrewed position in which the watch can be reassembled, put on time etc. and a screwed position in which the ring is screwed and locked on a tube driven or screwed into the middle of the watch case to compress a seal, thus improving the seal of the watch. The screwed position is therefore that which corresponds to the normal position when the watch is worn and which is more or less always the same with the wear of the seal near.

The manufacture and assembly of these crowns screwed on watch cases are well known. However, the methods of mounting these crowns are poorly suited to screwed crowns bearing on their end face an inscription or a pattern, for example a logo, a trademark or a similar sign. Indeed, the known assembly methods do not generally allow to bring the crown in a specific orientation relative to the box after screwing, which affects the aesthetics of the box when an inscription is affixed to the face of the box. end of the crown. This situation is of course unacceptable when these crowns equip luxury and high quality products.

A solution for adjusting in a specific position or orientation. a crown after screwing it on the tube has already been proposed in the document EP 1 124 167 A1 . According to this document, a shape memory alloy ring is placed either between the middle and the tube, or between the ring and the tube. By acting on the deformation of the ring, in particular by decreasing its diameter by subjecting the watch to determined temperatures, a temporary clearance between the caseband and the tube respectively between the crown and the tube can be created, which allows an angular adjustment of the crown in its screwed position. A disadvantage of this solution is that shape memory alloys are not commonly available in the form of small bars, so that it is difficult and expensive to machine the rings in question in the small dimensions required for the applications concerned.

The main object of the present invention is to overcome the drawbacks of the abovementioned prior art by providing a simple and economical screw-type crown with a motif such as a logo or a mark and in which the position of the logo or the mark affixed to the end face of said ring can easily be adjusted in a position or orientation determined after screwing the ring on the tube.

To this end, the subject of the invention is a screwed crown for a timepiece, comprising a head having a central part provided with connection means to a winding stem and a threaded side skirt intended to be screwed onto a corresponding thread of the timepiece, said ring being characterized in that it further comprises a cover having an end face, for example carrying a pattern, and extended by a wall surrounding the head laterally, in that the inner surface of the said wall comprises a first frustoconical surface portion, in that the head has a second portion of frustoconical outer surface that can cooperate with said first frustoconical portion of the cover and in that it further comprises elastic means tending to make integral, in less rotation, the hood on the head by jamming of the first and second portions of frustoconical surfaces.

Thanks to these features, the orientation of the pattern carried by the cover can be easily adjusted in a desired angular position relative to the middle when the ring is in its screwed position, without the aid of a tool. To do this, it suffices to pull axially on the bonnet against the elastic means to separate or in other words take off the first and second portions of respective frustoconical surfaces of the cover and the head. Once these surfaces are separated, the cover becomes free to rotate relative to the head, so that the manufacturer and the user can orient it in the desired position, the head remaining in its screwed position on the tube. It is then sufficient to release the hood so that the elastic means recall the hood in a wedging position in which the first and second portions of frustoconical surfaces cooperate.

Note that the fastening of the hood on the head via a wedging of complementary frustoconical surfaces has the advantage of allowing a precise adjustment, in any position, the hood relative to the head.

In addition, this new construction has the advantage of being invisible to the user from outside the crown, thus not altering the aesthetics of the latter.

This crown structure also has the advantage of being able to adjust the hood orientation not only at the time of mounting the crown on the box but also later for example to take account of the flattening and / or the wear of the joint arranged between the tube and the crown.

• la figure 1 est une vue de face d'une couronne selon l'invention dans une position vissée, le motif porté par la face frontale de son capot étant orienté dans une position quelconque par rapport à la carrure,
• la figure 2 montre une vue en coupe de la couronne à vis selon l'invention suivant la ligne II-II de la figure 1 ;
• la figure 3 est une vue en coupe similaire à la figure 2, la couronne étant représentée dans une position dans laquelle son capot est désolidarisé de la tête en vu de l'orientation angulaire dans une position déterminée du motif porté par le capot, et
• la figure 4 est une vue similaire à la figure 1 dans laquelle le motif porté par la capot est orienté angulairement dans une position déterminée par rapport à la carrure.

Other features and advantages of the present invention will appear in the following description of a preferred embodiment, presented by way of non-limiting example with reference to the accompanying drawings, in which:

• FIG. 1 is a front view of a ring according to the invention in a screwed position, the pattern carried by the front face of its cap being oriented in any position relative to the middle part,
• Figure 2 shows a sectional view of the screw ring according to the invention along the line II-II of Figure 1;
• FIG. 3 is a view in section similar to FIG. 2, the ring being represented in a position in which its cover is detached from the head in view of the angular orientation in a given position of the pattern carried by the cover, and
• Figure 4 is a view similar to Figure 1 wherein the pattern carried by the cover is oriented angularly in a specific position relative to the middle part.

In Figures 1 and 2, there is shown a screwed crown designated by the general reference 1. In these figures, the ring 1 is shown in the screwed position on a threaded tube 2 driven into a middle 6 of a watch case.

The ring 1 comprises a first portion formed of a head 8 having a tubular central portion 10 surrounded by a lateral skirt 12. The central portion 10 thus delimits with the skirt 12 an annular space intended to receive the threaded portion of the tube 2. A this effect the skirt 12 is provided in its lower part with an internal thread cooperating with the thread 2a of the threaded tube 2. In a conventional manner, the central portion 10 is connected to a winding stem (not shown) of the watch movement . In the example illustrated, the central portion 10 is attached and fixed in a central housing 14 of the head 8 and comprises a sleeve 16 in which a piston 18 slides against a spring 20. The piston 16 is intended for be connected to the winding stem. Typically, the central portion 10 is fixed for example by welding, gluing, crimping or any other suitable means in the central housing 14 formed in the head 8. A flat gasket 22 is also interposed between the bottom of the annular space and the front face of the threaded tube 2.

According to the invention, the ring 1 further comprises a cover 24 which is assembled on the head 8 so that the cover 24 and the head 8 are usually integral in rotation and axially of one another. The assembly of the cover 24 on the head 8 is made so as to be detachable or reversible.

The cover 24 is provided with an end or front face 26 on which is affixed a pattern such as a logo or M mark visible from outside the crown. Note in this connection that in Figure 1, the pattern is oriented in any position relative to the middle and that it is notably not aligned with respect to the upper face 6a thereof when the crown is in screwed position on the tube 2.

In FIG. 2 it can be seen that the hood 24 has a side wall 28 which surrounds the head 8 and which thus delimits a cavity intended to receive the head 8. The inner surface of the wall 28 comprises a first frustoconical surface portion 28a and the head 8 has a second frustoconical surface portion 8a that can cooperate with the first frustoconical surface portion 28a to provide a detachable or reversible assembly of the cover 24 on the head 8. This assembly is of the type of wedging of a frustoconical surface on the other. Preferably, the apex angle of the frustoconical surface portions of the cover 24 and the head 8 is typically between 1 ° and 20 ° depending on the couple of materials used for the head and the hood and the surface condition portions of frustoconical surfaces. It should also be noted in this connection that the second frustoconical surface portion 8a of the head 8 is followed downwards, that is to say at the level of the skirt 12, by an external diameter reduction which defines a shoulder 8b of which the function will be described below.

The ring 1 further comprises elastic means 30 which tend to apply the frustoconical surface portions to one another. In the illustrated embodiment, the elastic means 30 comprise an elastic annular lining which laterally surrounds the skirt of the head and which bears against the shoulder 8b of the head 8. A ring 32, surrounding a lower part of the head 8 is screwed onto an internal thread of the cover 24 and thus holds the cover 24 on the head 8 while compressing the elastic packing 30 axially so as to apply the portions of frustoconical surfaces of the head and the hood one on the other. For this purpose, the lining 30 has an elasticity in particular in a direction parallel to the axis of rotation A of the ring. Typically the annular seal 30 may comprise a seal of natural or synthetic compressible material of the O-ring type. Preferably, the resilient means 30 will be adjusted so as, on the one hand, to ensure a sufficient jamming guaranteeing a rotationally and axially fastening of the cover 24 and the head 8 during the usual manipulations of the ring 1 and, on the other hand, easy disconnection of the cover 24 of the head 8 manually, that is to say without the aid of a tool, to make an adjustment of the angular position of the cover 24 on the head 8. Note in this connection that the desired clamping force can be typically controlled by adjusting the compression ratio of the annular seal 30 in position of the cover 24 by a suitable clamping of the ring 32 on the cover 24.

The structure of the ring 1 and in particular the cone adjustment of the cap on the head with elastic support thanks to the ring 32 and the seal thus allow a relative reversible axial displacement of the cap 24 and the head 8 along the longitudinal axis A to secure or disengage in rotation the cover 24 and the head 8.

The cover 24 is therefore movable between a first so-called "fixed" position, in which the cover 24 is connected in rotation by jamming on the head 8 and in which the elastic seal 30 is compressed to a first degree of compression (FIG. 2), and a second position called "non-integral" in which the cover 24 is free to rotate about the longitudinal axis A relative to the head 8 and wherein the seal is compressed to a second degree of compression, greater than the first (FIG. 3).

Thus, when the ring 1 is screwed in abutment on the driven tube 2, the cover 24 carrying the pattern M can be easily moved angularly in a desired position by proceeding as follows. From the so-called integral position shown in FIG. 2, the cover 24 is grasped between two fingers and is displaced axially in the direction of the arrow F so as to detach the portions of frustoconical surfaces from one another and to compress the elastic seal 30. At this time the cover 24 is in its so-called non-integral position (Figure 3). The hood 24 being held in this position it can be oriented by rotating in the direction of the arrow R in a desired angular position. Once the desired angular position is reached, simply release the cover 24 which is then returned to its integral position by the expansion of the seal 30. In doing so, the frustoconical surface portions of the cover and the head cooperate again. one with the other to axially and rotationally secure the hood to the head by wedging.

It should be noted that the use of a head-mounted hood allows the crown maker to have a stock of standard heads and to use these heads with hoods bearing different patterns or other items such as gemstones. or the like.

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the embodiment described herein without departing from the scope of the present invention defined by the appended claims. In particular, it will be possible to use a spring ring corrugated instead of the annular seal, since it has elasticity in compressibility along the axis A. According to a variant can also be provided that one or other of the frustoconical surfaces or both are rough for example striated. It will also be noted that the invention described above can be applied to the angular positioning of crowns having non-cylindrical outer shapes, for example square, oval or any other particular shape.

Claims (8)

Screwed crown for a timepiece, comprising a head having a central portion provided with connection means to a winding stem and a threaded side skirt intended to be screwed onto a corresponding thread of the timepiece, characterized in that it further comprises a cover having an end face and a wall laterally surrounding the head, in that the inner surface of said wall comprises a first frustoconical surface portion, in that the head has a second portion of outer frustoconical surface; which can cooperate with said first frustoconical portion of the cover and that it further comprises elastic means tending to make integral, at least in rotation, the cover on the head by wedging of the first and second portions of frustoconical surfaces. Screwed crown according to claim 1, characterized in that the means for securing by wedging of the frustoconical walls of the head and the cover are provided so that the jamming of the cover on the head is reversible. Screwed crown according to claim 2, characterized in that the fastening and the detachment in rotation of the cover and the head are formed by a relative axial displacement of the cover and the head along the axis of rotation of the ring. Screw-in crown according to claim 3, characterized in that it comprises a ring surrounding said head and screwed onto the cover and in that the elastic means comprise an elastic seal which extends between the ring and the head. Screw-in crown according to Claim 4, characterized in that the cover is movable between a first "fixed" position, in which the cover is secured in rotation by jamming on the head and the elastic seal compressed to a first degree of compression, and a second so-called "non-integral" position in which the hood is free to rotate about the longitudinal axis relative to the head and wherein the lining is compressed to a second degree of compression greater than the first degree of compression. Screw-in crown according to claim 4 or 5, characterized in that the elastic seal comprises an O-ring type seal. Screw-in crown according to one of the preceding claims, characterized in that the angle at the apex of the frustoconical walls of the cover and the head is between 1 ° and 20 °. Screw-in crown according to one of the preceding claims, characterized in that said end face bears a pattern.

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