HK40002668B - Device for attaching a bracelet - Google Patents

Description

Device for attaching the chain

Technical Field

The present invention relates to the field of timepieces or jewellery. More particularly, the present invention relates to a method for attaching a strap or chain to an object, in particular a watch case.

Background Art

Typically, a leather or metal strap or chain is attached to the lugs of a watch case by means of a bar formed by a tube inside which are mounted two pistons that move in translation, and an elastic element placed between them and used to drive them towards the outside of the tube. The bar is mounted at one end of the chain in a housing provided for this purpose, and the pistons engage in blind holes formed opposite them in the lugs of the case.

To remove a strap or chain attached to the case in this way, a tool is required, designed to push the piston back into the tube against the stress exerted by the elastic element, thereby removing it from the hole. Watch owners do not always have such a tool, and using it is inconvenient. This is why chains equipped with this type of attachment are usually permanently fixed to the case.

There are also attachment devices that allow the chain to be removed from the housing without the use of tools. This device often consists of a rod of the type described above, onto which an element for actuating the pistons is mounted through the tube. The actuating element is, for example, a radial finger integral with one of the pistons, as described in Swiss Patent CH327838. The finger is slidably mounted through an axial slot formed in the tube, and its movement along the slot pushes one of the pistons within the tube.

CH614589 discloses a watch case having a device for attaching a strap to the case, wherein the central lug has a cylindrical channel split longitudinally over the entire length of the lug to allow a rod for attaching the strap to be inserted in. The rod is in the form of a cylinder having a flat portion over its entire length to allow the rod to pass when it is inserted into the channel and to hold the rod in place when it occupies a certain angular position.

Thus, the attachment devices described are often used with interchangeable chains or straps, allowing users to replace them as needed. However, they are not without drawbacks. In particular, they require significant structural modifications to the rod, such as openings in the tube or modifications to the piston. These changes result in significant additional manufacturing costs. These attachment devices also have protruding elements, namely actuating elements, that can snag or catch on or injure the wearer of the watch.

Summary of the Invention

The present invention overcomes the aforementioned drawbacks by proposing a device for attaching a chain or a strap to a watch case, said device comprising, on the one hand, a rod fixed to the watch case by means of at least one lug, and, on the other hand, an insert integral with the end of the chain, wherein said rod and insert are complementary so as to cooperate by fitting one inside the other to form a removable assembly device making the chains interchangeable.

According to the invention, the rod is formed by a cylindrical mandrel having at least one flat portion, the flat portion being arranged to cooperate by mating with at least one non-through housing formed in the insert, the non-through housing having a substantially rectangular opening for receiving the at least one flat portion of the rod, the rod comprising at least one control element for pivoting the rod from a first position A in which the flat portion of the rod can receive the insert to a second position B in which the insert is locked to the rod.

According to other advantageous variants of the invention:

- the control element comprises an axial retaining element formed by at least one shoulder at at least one end of the rod;

- said axial retaining element co-operates with a lateral stop surface of the watch case;

- said at least one shoulder comprises a groove arranged to cooperate with a tool;

- said shoulder comprises a guide mark indicating a first position A;

- the rod comprises a flat portion near each of its ends;

- the watch case comprises means for maintaining the position of the stick, said maintaining means comprising at least one ball catch arranged to cooperate with a cavity formed on the arbour of the stick;

- the watch case comprises a middle lug having a channel with a diameter corresponding to the diameter of the rod's arbors;

- the intermediate lug comprises a removable cover held on the case by means of screws;

- The insert has a C-shaped cross section.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will become more apparent from the following detailed description of an exemplary embodiment of the device for attaching a chain according to the invention, which example is given entirely by way of non-limiting illustration with reference to the accompanying drawings, in which:

- Figures 1a to 1d show respectively a perspective view and a cross-sectional view of a watch case equipped with an attachment device according to the invention;

- Figures 2a and 2b show the same watch case before its chain is attached;

- Figures 3a to 3c show the attachment device according to the invention during the chain attachment process;

- Figures 4a to 4c show the attachment device according to the invention during chain locking.

DETAILED DESCRIPTION

1a to 1d show details of a wristwatch and of a device for attaching a chain 2 to a watch case 1 according to a preferred embodiment of the invention. The device for attaching a chain 2 to a watch case 1 comprises, on the one hand, a rod 4 fixed to the watch case by means of at least one lug integral with the case, and, on the other hand, an insert integral with the end of the chain 2, wherein the rod 4 and the insert 20 complement each other so as to cooperate by fitting one inside the other, thereby forming a removable assembly device enabling the chains to be interchangeable.

As can be seen in Figures 1c and 1d, the watch case includes a central lug having a channel whose diameter corresponds to the diameter of the spindle of rod 4, allowing it to rotate freely within its housing. Central lug 10 is formed from two parts: a first part 11, formed integrally with the watch case and including a slot 110 arranged to receive rod 4; and a second part formed by a removable cover 12, which is retained on the first part, and thus on watch case 1, by means of screws 13. This arrangement allows rod 4 to be assembled and disassembled simply and quickly, without risk of damaging or distorting the rod.

Advantageously, watch case 1 includes means for maintaining the position of rod 4. As shown in FIG1 c , these maintaining means take the form of a pair of ball detents 14, each of which is arranged to cooperate with a first pair of cavities 42 and a second pair of cavities 42′ formed on arbour 40 of rod 4. Of course, a person skilled in the art will be able to adopt other alternatives to the ball detents, such as a spring or a jumper resting on a flat portion.

According to the invention, the rod 4 is formed by a cylindrical mandrel 40 having at least one flat portion 41 arranged to cooperate by fitting with at least one housing 21 formed in an insert 20 of a chain part 2 or link.

The accommodation portion 21 has a substantially rectangular opening 210 for receiving the flat portion 41 of the rod 4 , the height and length of the opening 210 corresponding to the height and length of the flat portion 41 of the rod 4 .

According to the preferred embodiment of the invention shown in the accompanying drawings, the rod 4 has two flat portions 41 arranged close to each end of the rod 4 , so that there is one flat portion 41 on each side of the intermediate lug, each flat portion 41 cooperating with an insert 20 .

Advantageously, the rod 4 has at least one control element for pivoting it from a first position A, in which the flat portion 41 of the rod 4 can receive the insert, to a second position B, in which the insert is locked to the rod 4 .

According to a particular embodiment of the invention, the rod 4 can be returned from position B to position A by elastic return means such as a jumper spring on the cam or a torsion spring on the rod.

As shown, the control element includes a shoulder 43 integral with each end of the rod 4, so that the rod 4 and the shoulder 43 form a single element. It is also conceivable that the shoulder 43 is assembled to the end of the rod 4 by means of an insertion tip that is mounted in the hollow portion of the rod 4. In this case, an internal projection is provided at the end of the rod 4 to cooperate with the insertion tip to snap the shoulder 43 into the rod 4. Other ways of securing the shoulder 43 are conceivable, such as adhesive bonding, welding/soldering, or press fitting. These shoulders serve as axial retaining elements for the rod 4 and the insert 20.

Thus, the rod 4 can consist of three parts, or it can be formed as just one piece, wherein the shoulder 43 is preformed at the end of the mandrel 40 and then the flat portion 41 and the cavities 42, 42' are milled directly into the mandrel 40. Furthermore, the cross-sections of the mandrel 40 and of the shoulder 43 of the rod 4 are preferably chosen to be cylindrical in order to facilitate the degree of freedom of rotation about the axis A-A.

Advantageously, the intermediate lug 10 acts as a radial retaining element, complementary to the groove 110, whose shape and depth complement those of the mandrel 40, so that once the rod 4 is set in position, it cannot come out of the groove 110. In Figures 1c and 1d, it can be noted that the intermediate lug 10 has two housings for receiving the ball catch 14, which is arranged to cooperate with the cavities 42, 42' of the rod 4, their respective dimensions and depths being configured so that when the ball catch 14 is engaged in the cavity 42 or 42' of the rod 4, the rod 4 no longer has any degree of freedom in the groove 110.

As can be seen in Figures 2a and 2b, the attachment device includes a housing 21 formed in the chain section insert 20. The housing 21 takes the form of an open housing formed by a cylindrical slot 211 disposed within the chain section insert 20. This cylindrical slot 211 has a rectangular opening 210 for inserting and retaining a cylindrical rod 4, which has two flat portions 41 to match the shape of the housing. Thus, as can be seen in the cross-sectional views of Figures 2b and 3b, the slot 211 has a C-shaped cross-section.

According to the preferred embodiment shown in Figures 1a to 1d, watch case 1 has a first vertical side wall, facing which is provided in the case middle part an undercut 101 for accommodating therein shoulder 43. Since shoulder 43 preferably has a cylindrical shape in this case, undercut 101 has a matching, hollowed-out cylindrical shape in watch case 1.

As shown in Figures 3a and 3b, to attach the chain 2 to the housing 1, the insert 20 (which corresponds to, for example, the end of a chain section) is inserted into the rod 4 by positioning the opening 210 of the receptacle 21 opposite the flat portion 41 of the rod 4 to accommodate the rod 4 within the receptacle 21. To facilitate the correct positioning of the flat portion 41, a guide mark 44 is provided on at least one of the shoulders 43 to indicate a first position A of the rod 4 for positioning the insert 20. Furthermore, the ball catch 14 is arranged to cooperate with the first cavity 42 of the spindle 40 once the guide mark 44 becomes visible to the user, thereby locking the spindle 40 in position A.

Once the insert 20 is in place on the rod 4, the user pivots the rod 4 about the axis A-A to position B by means of the shoulder until the flat portion 41 is angularly offset by at least 45°, more preferably 90°, about the axis A-A, so that the chain portion can no longer be displaced, as can be seen in FIG4 b . To retain the insert 20 in this position, the ball catch 14 now cooperates with a second pair of cavities 42 ′ that are angularly offset by the same amount about the axis A-A.

According to the invention, at least one of the shoulders 43 has a slot 45 arranged on its outer surface, that is to say the face visible to the wearer of the watch, to cooperate with a tool or the user's finger to facilitate the manipulation of shoulder 43 and the locking and/or unlocking of insert 20 on rod 4.

Advantageously, insert 20 matches the shape of intermediate lug 10 so as to limit play during assembly and provide a high-quality fit.

In the above embodiment, the insert is arranged on a chain or a belt made of leather, synthetic fabric, plastic, metal, ceramic or a composite material. Similarly, the rod 4 is preferably made of metal, but may also be made of plastic, ceramic or a composite material.

One result of these various aspects of the invention is that a secure chain attachment device is provided which allows for simple and quick chain changes.

Of course, the present invention is not limited to the described examples, but is subject to various variations and modifications that may occur to those skilled in the art.

Claims (14)

1. An attachment device for attaching a chain or strap (2) to a watch case (1), the attachment device comprising, on one hand, a bar (4) secured to the watch case (1) by means of at least one lug (10), and on the other hand, an insert (20) integral with the end of the chain, the bar (4) and the insert (20) being complementary so as to form a removable assembly capable of interchangeable chains by cooperating within the other through a fit between the two. The rod (4) is characterized in that it is formed by a cylindrical mandrel (40) having at least one planar portion (41) arranged to cooperate with at least one receiving portion (21) formed in at least one of the inserts (20), the at least one receiving portion (21) having a generally rectangular opening (210) for receiving the at least one planar portion (41), the rod (4) including at least one control element for pivoting the rod about an axis (A-A) from a first position (A) to a second position (B), in the first position (A) the insert (20) can be positioned on the mandrel (40) of the rod (4), in the second position (B) the insert is locked on the mandrel (40) of the rod, wherein the control element can be operated by a user's finger on an outer surface, and the rod can be returned from the second position (B) to the first position (A) by a resilient return device. 2. The attachment device according to claim 1, wherein the control element includes at least one shoulder (43) at at least one end of the rod (4), the at least one shoulder (43) forming an axial retaining element. 3. The attachment device according to claim 2, wherein the at least one shoulder (43) cooperates with at least one lateral stop surface of the watch case (1). 4. The attachment device according to claim 2, wherein the at least one shoulder (43) includes a slot (45) arranged to cooperate with the tool to pivot the rod (4) about an axis (A-A). 5. The attachment device according to claim 2, wherein the shoulder (43) includes a guide mark (44) indicating a first position (A) of the rod (4). 6. The attachment device according to claim 1, wherein the watch case (1) includes a holding device for maintaining the position of the bar, the holding device including at least one ball stop (14) arranged to cooperate with at least one cavity (42, 42') formed on the spindle (40) of the bar. 7. The attachment device according to claim 6, characterized in that the mandrel (40) has a first pair of cavities (42) arranged to cooperate with a pair of ball stops (14) when the rod is in the first position (A). 8. The attachment device according to claim 7, characterized in that the mandrel (40) has a second pair of cavities (42') arranged to cooperate with a pair of ball stops (14) when the rod is in the second position (B). 9. The attachment device according to claim 8, wherein the first pair of cavities (42) and the second pair of cavities (42’) are offset 45° about the axis (A-A). 10. The attachment device according to claim 8, wherein the first pair of cavities (42) and the second pair of cavities (42’) are offset 90° angularly about the axis (A-A). 11. The attachment device according to claim 1, wherein the watch case includes a central lug having a channel with a diameter corresponding to the diameter of the mandrel of the bar. 12. The attachment device according to claim 11, characterized in that the rod (4) has a planar portion (41) near each end of the rod, one planar portion (41) being disposed on one side of the intermediate lug (10). 13. The attachment device according to claim 11, characterized in that the intermediate lug (10) includes a removable cover (11) held on the watch case (1) by means of a screw (13). 14. The attachment device according to claim 1, characterized in that the receiving portion (21) takes the form of a groove (211) with an opening (210) and the receiving portion (21) has a C-shaped cross section.