HK1198880B - Bracelet clasp comprising a device for adjusting the usable length of the bracelet - Google Patents

Description

Chain shackle comprising an adjustment device for adjusting the usable length of the chain

Technical Field

The present invention relates to a bracelet clasp comprising a first free end and a second free end, wherein the clasp comprises a first and a second fastener of a bracelet to be formed integrally with the first and second free ends of the bracelet, respectively, wherein the fasteners are movable relative to each other between at least one open position and a closed position for wearing to close the bracelet and to determine the usable length of the bracelet, the fasteners being closer to each other in the closed position than in the open position. The clasp includes at least one locking member arranged to retain a fastener of a bracelet in a closed position and at least one control member for the locking member arranged to unlock the bracelet clasp and move from the closed position to the open position in response to a user action. Furthermore, the clasp according to the invention comprises an adjustment device for adjusting the usable length of the bracelet, comprising an adjustment member carrying said first fastening member of the bracelet and at least one latch able to have a default closed condition, in which said adjustment member is fixed, and an open condition, in which said adjustment member is free to slide in the length direction of the bracelet with respect to said second fastening member of the bracelet to change the usable length of the bracelet.

The invention also relates to a watch fitted with such a clasp.

Background

The problem with the need to provide an adjustment device for adjusting the usable length of the chain is well known.

On the one hand, in the case of a chain formed of links, the circumference of the user's wrist may have a difference between two configurations of the chain, which differ from each other by one link. This is also the case when the chain, made of leather, rubber or the like, has perforations which do not allow a sufficiently fine adjustment. It is therefore useful to provide an adjustment device that allows finer adjustments to be made to the chain length than removing or adding links to adjust the usable length of the chain.

On the other hand, it is also known that the value of the circumference of the wrist varies with the seasons, generally reaching a maximum in summer and a minimum in winter. It is therefore also preferred to provide a fine adjustment means for adjusting the usable length of the chain, so that the wearer of the chain can adjust the chain length to improve wearing comfort.

By way of example, patent application EP09131060a1 discloses a clasp with an unfolding buckle comprising a cover with a series of pairs of holes for receiving the ends of the connecting rods of a bracelet. To solve the above problem, two pairs of adjacent holes are spaced apart by a distance to define an adjustment pitch for the usable length of the chain.

However, the length adjustment of the respective chains is difficult, since the adjustment has to be carried out using a pointed tool. Not only does this require some dexterity, but if the person performing the adjustment is clumsy, there is a risk of damage to the lid.

To avoid this, alternative means are disclosed in, for example, patent EP0350785B1, which discloses a clasp similar to the above, but which instead includes means by which the usable length of the bracelet can be adjusted without tools. In fact, the clasp disclosed in this patent is of the type with an unfolding buckle comprising two strips hinged to each other by means of a pin passing through both of them, wherein each strip has at its free end a fastener of a bracelet. The first strip carries a hook for engagement in a hole arranged on the second strip, in order to cooperate there with a spring pin for locking the hook and thus the clasp in the closed condition. The second bar comprises two portions slidable with respect to each other within a predetermined range, which define an adjustment pitch of the usable length of the adjustment chain. A first of said two parts carries a hinge connecting it to the first bar, while the second part carries a locking spring pin. The hole in which the hook engages to lock the clasp has a length in the longitudinal direction of the bracelet that corresponds to the sliding range of the two parts of the second strip. The spring pin has a central portion defining two positions for the hook portion in the longitudinal direction of the chain, which correspond to two different available chain lengths. The control member, which in particular comprises a pusher, allows to actuate the spring pin to release the hook and open the clasp.

Therefore, the clasp described in this patent must be opened for length adjustment.

It should be noted that one disadvantage of this structure is that: the length adjustment of the bracelet is lost each time the clasp is opened. The wearer of the chain must therefore ensure that the hook part is inserted from the side of the middle part of the spring pin matching the required chain length.

As an alternative to avoid such drawbacks, adjustment devices comprising a dedicated locking member have also been proposed.

Patent application EP1378185a1 provides one such example. However, these devices generally have a complex and conspicuous design, since they may comprise at least one control for locking the clasp, at least one additional control for locking the adjustment device.

Disclosure of Invention

The main purposes of the invention are: the drawbacks of the known prior art clasps are overcome by proposing a clasp for a bracelet with an adjustment device that is easy to operate, having a simple structure for adjusting the usable length of the bracelet, including when the clasp is open, by preferably providing a firm adjustment.

On this basis, the invention relates more particularly to a clasp of the type described above, characterised in that the adjustment means are separate from the blocking element, the latch being arranged to be moved from the closed condition to the open condition by the user acting on a control element of said blocking element, so that said adjustment element can be moved independently of the open or closed condition of said clasp.

Due to this feature, the adjustment device according to the invention has a compact structure, since, although it is separate from the locking member of the clasp, it is actuated by a control member for unlocking the clasp, and this additionally allows adjusting the length of the bracelet even when the clasp is in its closed state.

In general, it may be advantageous to associate the unlocking of the clasp with a displacement of the control element having a first amplitude d1, and the unlocking of the adjustment element by the latch with a displacement of the control element having a second amplitude d2, wherein d1 is smaller than d 2.

Thus, the clasp may be unlocked without unlocking the adjustment member, which ensures that the required adjustment is still maintained during opening of the clasp, unlike the prior art clasps described above.

Furthermore, the adjustment piece preferably comprises a support structure carrying the first fastening piece of the chain and at least one finger arranged to cooperate with the latch, which latch comprises a disc portion which abuts the support structure and is provided with a slot in the radial direction of the chain. The slot has at least two notches that are capable of cooperating with the finger in the closed state of the latch to respectively define two different available lengths of chain, the finger being capable of sliding into the slot in the open state of the latch to move from one notch to the other and change the available length of chain.

According to a preferred variant, the supporting structure comprises an upper wall and a lower wall, the disc being arranged between the upper wall and the lower wall, the finger taking the form of a screw that fixes the upper wall and the lower wall to each other.

It may also be provided that the upper wall is formed by a cover comprising an upper surface carrying a side wall having two holes for receiving the ends of the fastening strips of the chain and at least one support surface against which the lower wall is held by the screws.

It may also be provided that the control comprises a pusher movable in a direction substantially perpendicular to the longitudinal direction of the chain in response to a user action, the latch being integral with the pusher.

In general, it may be provided that the bracelet clasp has an additional control, wherein the control is similar and symmetrical with respect to the longitudinal direction of the bracelet, the adjustment means comprising an additional latch associated with the additional control and an additional finger associated with the additional latch, wherein the latch is similar and symmetrical with respect to the longitudinal direction of the bracelet.

According to a preferred embodiment, the bracelet clasp is a clasp of the spread clasp type comprising at least two strips hinged to each other, wherein a first strip comprises two posts symmetrical with respect to the longitudinal direction of the bracelet, and said posts are inserted into complementary recesses of a second strip in order to place the bracelet clasp in a closed position by simply bringing the posts closer to each other against the force of an elastic return means, wherein the outer edge of each post cooperates with the inner edge of the corresponding recess to define a locking element of the bracelet clasp. It may thus advantageously be provided that each of said studs of the first bar carries one of said pushers and one of said latches. Each bar may be made in one piece with the corresponding pusher and latch.

In general, it may also be provided that the adjustment means comprise at least one elastic element which exerts a force on the latch in an effort to keep the latch in the closed state.

In this case, the adjustment means preferably comprise an intermediate member located in a fixed position with respect to the latch and having a bearing surface for the end of the elastic member.

The adjustment device further comprises a stud (studctch) associated with at least two complementary openings arranged to identify at least two configurations corresponding to two different available lengths of the chain. The pin may thus be carried by the intermediate member. In this case, the opening may be arranged on an upper wall of the adjusting device.

Drawings

Further characteristics and advantages of the invention will emerge more clearly from a reading of the following detailed description of a preferred embodiment, given by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1 is a simplified overall perspective view of a snap clasp according to a preferred embodiment of the present invention when closed;

FIG. 2 is a partially exploded perspective view of the clasp of FIG. 1 when open;

FIG. 3 is a simplified cross-sectional view of a design detail of the clasp of FIG. 1 in a first configuration;

FIG. 4 is a view similar to FIG. 3, showing the clasp in a second configuration;

FIG. 5 is an exploded perspective view of the snap hook according to the preferred embodiment of the present invention when closed;

FIG. 6 is a simplified cross-sectional view of a design detail of the clasp of FIG. 5; and

FIG. 7 is a longitudinal cross-sectional view of the clasp of FIG. 5.

Detailed Description

The clasp shown in a non-limiting manner in the attached drawings corresponds to a preferred embodiment of the invention. More specifically, the clasp 1 is a clasp of the type with an unfolding clasp and is used for a watch bracelet or bracelet.

As shown more particularly in fig. 1, clasp 1 comprises a first strip 2, first strip 2 being hinged on a second strip 4 by a spindle 6, spindle 6 here being constituted by a pin, shown in a non-limiting manner, riveted to strip 4. Each strip has an elongated shape in the longitudinal direction of the chain and is slightly curved to better fit the shape of the wearer's wrist.

The first strip 2 comprises two columns 8, which two columns 8 are arranged to contact each other at their ends on the side of the mandrel 6, each column having a cut-out so that the columns do not contact each other over most of their length.

Each post 8 carries, near its end remote from the arbour 6, an extension 10 which extends in a direction perpendicular to the longitudinal direction of the bracelet to form a pusher defining a control for opening the clasp, as shown in fig. 2.

Furthermore, the free end of the first bar 2 carries an adjustment device 12, which adjustment device 12 is used to adjust the available length of the bracelet to be attached to the clasp 1.

The adjustment device 12 includes a cover 14, the cover 14 having an upper wall 16, the upper wall 16 carrying a side wall 18. The side wall 18 is provided with two holes which allow to receive the ends of the fastening rods 20 of the chain in a conventional manner.

Fig. 2 shows an exploded perspective view of the clasp 1 when opened.

As can be seen clearly in fig. 2, the second bar 4 comprises two arms 22, the two arms 22 being connected together by a crosspiece 24 located in their central zone. The arm 22 extends through a curved portion 26, the curved portion 26 carrying a fastening plate 28 of the chain, the fastening plate 28 being offset with respect to the general direction of the arm 22 to define a passage for the chain.

The fastening plate 28 has a plurality of holes 30, said holes 30 being evenly spaced from each other to allow the placement of a round head threaded stud (pillarwrew) 32, the stud 32 being intended to engage in a hole in the bracelet to ensure that the bracelet is fixed to the clasp and a screw (not shown) is screwed into this stud 32. In addition, each curved portion 26 has a small protrusion 34 for improving the holding effect of the bracelet strand when the bracelet strand is positioned on the clasp 1. The cross-post 24 carries an optional post 36 or screw for engagement in another hole in the bracelet to further enhance the retention of the bracelet on the clasp. The threaded post 32 may be placed in one hole 30 or the other to define a distance between the post 32 and the post 36 corresponding to the overall number of hole pitches arranged on the chain.

The space between the arms 22 of the second strip 4 defines, in a known manner, a recess for housing the first strip 2 in the closed condition of the clasp 1.

Conventional locking means are provided to ensure that the clasp remains in the closed condition. The outer edge of the column 8 has a thickening 38 close to the pusher 10, said thickening 38 being intended to cooperate by friction with the inner edge of the second bar 4 at the recess. In particular, each inner edge of the second bar has a hollow (hold) 40, in which hollow 40 the respective thickened portion of the first bar 2 engages when the clasp is closed. The cut-out formed on each post 8 frees up a space that allows the posts 8 to approach each other against the force of the elastic return means when locking the clasp or when actuating the pusher 10 to release the thickened portion 38 from the hollow 40 to open the clasp.

The above-mentioned patent application EP09131060a1 discloses in detail a clasp of this type, to which the skilled person can refer if necessary.

Each pusher 10 extends through a latch 42 of an adjustment device for adjusting the usable length of the chain.

Each latch 42 comprises a plate 44 with a slot 46, the slot 46 being oriented in the longitudinal direction of the chain and having two notches 48 at its ends.

The latches are shaped to define a T-shaped opening therebetween for cooperating with the intermediate member 52 to ensure that the intermediate member 52 is retained relative to the latch 42.

The first function of the intermediate member 52 is to provide a bearing surface for a first end of the spring 54, a second end of the spring 54 resting on the corresponding plate 44, these springs being arranged to keep the latch 42 in the closed condition, as will be seen below in the detailed description of fig. 3 and 4.

The second function of the intermediate member is to act as a support to improve the structural stability of the adjustment device.

In fact, as is clear from fig. 2, the support structure of the adjustment device comprises a lower wall 56, the lower wall 56 being integrally connected to the upper wall 16 of the cover 14 by means of two screws 58. The upper wall 16 and the intermediate member 52 also provide respective bearing surfaces against which the lower wall 56 is disposed, thereby improving the stability of the respective assembly.

A screw 58 is disposed through slot 46 and through an appropriate slot 60 disposed in intermediate member 52.

The latch 42 is thus disposed between the lower wall 56 and the upper wall 16 and is held there by the cooperation of the slot 46 and the screw 58.

The method of operation of the adjustment device according to the invention will now be described with reference to fig. 3 and 4, which show similar simplified cross-sectional views along a middle plane with the adjustment device in a first configuration and a second configuration, respectively.

More specifically, fig. 3 corresponds to the long configuration of the clasp, i.e. the configuration in which the usable length of the bracelet is the greatest, while fig. 4 corresponds to the short configuration of the clasp, i.e. the configuration in which the usable length of the bracelet is the shortest.

In fig. 3 and 4, the upper half shows the first latch 42 in the closed state, while the lower half shows the second latch 42 in the open state.

When the pusher 10 is free, the shape of the column 8 in the rest condition, assisted by the action of the spring 54, keeps each latch 42 in the deployed position corresponding to the closed condition.

In this configuration, each screw 58 is located in one of the notches 48, the support structure cannot move in the longitudinal direction, or the chain cannot move relative to the latch 42.

When the pusher 10 is actuated, the latches 42 move closer to each other to move into their open state (lower half of fig. 3 and 4).

The notches 48 move during this operation, the screw 58 thus lying on the axis of the slot 46 and thus being able to slide along the slot to come into position opposite one notch 48 or the other as required. Thus, when the user actuates pusher 10 to place latch 42 in the open state, the user can then move lid 14 and move lid 14 in the longitudinal direction of the chain to change the available length of the chain. When the screw 58 is once again opposite one of the notches 48, the column 8 returns to the rest shape due to the simultaneous action of the elasticity and the spring 54, if the pusher 10 is not operated by the user. This action returns the latch 42 to the closed condition and thus locks the adjustment member including the cover 16 associated with the lower wall 56 and the screw 58.

Comparing fig. 3 and 4, it is evident that in the configuration of fig. 3, the length of the overlapping portion of the bracelet strand is less than in the configuration of fig. 4, assuming that the bracelet is assembled to the clasp 1, which means that the configuration of fig. 3 corresponds to a greater usable length of the bracelet than the configuration of fig. 4.

Furthermore, a comparison of the lower half of fig. 3 with the upper half shows: a first deformation amplitude d1 of the posts 8 allows the clasp 1 to be unlocked, while a second deformation amplitude d2 of the posts 8 greater than the first amplitude d1 is necessary to release the screws 58 and allow them to slide into the slots 46. Thus, it is possible to provide in a preferred manner by design the solution of opening the clasp 1 without changing the adjustment achieved by the adjustment device according to the invention.

Furthermore, this particular feature also allows the length of the clasp to be adjusted when it is open and then also advantageously maintains this adjustment.

Figures 5 to 7 show a variant of the clasp just described. For the sake of simplicity of illustration, elements which are identical to those of the embodiment which has just been described have the same reference numerals and only the different features are described in detail.

Fig. 5 shows an exploded perspective view of the snap hook 100 in its closed configuration, the snap hook 100 having the same general structure as the snap hook 1.

Clasp 100 differs from clasp 1 in the configuration of its adjustment means 112 for adjusting the usable length of the bracelet.

The adjustment device 112 comprises two latches 142 integral with the posts 108 of the first bar 102 of the clasp 100, wherein a pusher is also provided for opening the clasp and allowing the latches 142 to move from their closed state to their open state.

The intermediate member 152 is arranged between the lower 156 and upper 116 walls of the adjustment device and is held in the longitudinal direction of the chain by a thickened portion 162 arranged on each latch 142.

In addition to the functions already described with respect to the intermediate member 52, the intermediate member 152 carries a pin (studctch) 164 for ensuring the identification of the different possible adjustment configurations.

As best seen in fig. 5, the upper wall 116 has an opening 166 for cooperation with the post of the stud 164.

The arrangement of the adjustment device 112 can be seen more clearly in fig. 6, which shows a sectional view thereof along a middle plane.

The intermediate member 152 includes a small protrusion 168 defining two bearing surfaces for a first end of the spring 154, the spring 154 acting on the latches 142 to hold them in the closed state.

FIG. 7 illustrates a longitudinal cross-sectional view of the snap hook 100, thus better illustrating how the stud 164 cooperates with the upper wall 116 of the cover 114 to identify the possible different adjustment positions of the snap hook 100.

The clasp 100 is shown in its long configuration in FIG. 7. As is apparent from the above explanation, if the cover 114 is moved leftward in the drawing, the chain (not shown) is shortened.

As is clear from the present description, the clasp according to the invention comprises an adjustment device for adjusting the usable length of the bracelet, which is simple in structure and easy to operate, while preserving a compact aesthetic appearance and reducing the space requirements.

The above description is intended to describe a particular embodiment by way of non-limiting example, the invention is not limited to the use of some of the particular features just described, such as the shapes of the bars specifically shown and described or their cooperation for ensuring the locking clasp. In fact, for example, hook or spring-pin type locks may be used instead, such as described in patent EP0350785B1 mentioned above in relation to an adjustable clasp, consistent with the features of the present invention.

Those skilled in the art will not encounter any particular difficulty in modifying the content of the invention to suit their personal needs and in constructing clasps, particularly for timepieces, without departing from the scope of the invention. It is noted that, for example, those skilled in the art will not encounter any particular difficulty in adapting the teachings herein to the design of a deployment buckle having a different configuration than that shown and described.

Furthermore, the clasp according to the present invention is not limited to the use of two adjustment positions for the available length of the bracelet. Indeed, similarly, the skilled person will not encounter any particular difficulty in adapting the teachings herein to the construction of clasps having a greater number of possible adjustment positions.

Claims (14)

1. A clasp (1, 100) of the type comprising a first free end and a second free end, wherein the clasp comprises:

first and second fastener members (20, 32) of a chain, the fastener members (20, 32) being intended to be formed integrally with a first free end and a second free end of the chain, respectively, wherein the fastener members (20, 32) are movable relative to each other between at least one open position and a closed position for wearing, to close the chain and to determine the usable length of the chain, the fastener members (20, 32) being closer to each other in the closed position than in the open position,

at least one locking member (38, 40), said locking member (38, 40) being arranged to hold said fastener (20, 32) of the chain in a closed position,

at least one control member (10) for the locking member (20, 32), the control member (10) being arranged to unlock the bracelet clasp (1, 100) and move from the closed position to the open position in response to a user action, and

adjustment means (12, 112) for adjusting the usable length of the chain, the adjustment means (12, 112) comprising:

an adjustment member (14, 16, 56, 58), the adjustment member (14, 16, 56, 58) carrying the first fastener (20) of the chain, and

at least one latch (42, 142) capable of having a default closed condition in which the adjustment member (14, 16, 56, 58) is secured, and an open condition in which the adjustment member (14, 16, 56, 58) is free to slide in a chain length direction relative to the second fastener (32) of the chain to change a usable length of the chain,

wherein the adjustment device (12, 112) is separate from the lock (38, 40), the latch (42, 142) being arranged to be moved from a closed state to an open state by a user acting on the control member (10) of the lock (38, 40), so that the adjustment member (14, 16, 56, 58) can be moved independently of the open or closed state of the clasp,

characterized in that the adjustment piece comprises a support structure (14) carrying the first fastener (20) of the chain and at least one finger (58) arranged to cooperate with the latch (42, 142), wherein the latch (42, 142) comprises a disc portion (44), which disc portion (44) adjoins the support structure and is provided with a slot (46) in the radial direction of the chain, wherein the slot (46) has at least two notches (48) which can cooperate with the finger (58) in the closed state of the latch (42, 142) to define respectively two different usable lengths of the chain, the finger (58) being slidable into the slot (46) in the open state of the latch (42, 142) to move from one notch (48) to the other and change the usable length of the chain.

2. The snap hook (1, 100) according to claim 1, characterized in that the support structure comprises an upper wall (16) and a lower wall (56), the pan (44) being arranged between the upper and lower walls, the finger (58) taking the form of a screw that fixes the upper and lower walls (16, 56) to each other.

3. The clasp (1, 100) according to claim 2, wherein the upper wall (16) is formed by a cover (14), the cover (14) comprising an upper surface and at least one bearing surface, the upper surface carrying a side wall (18), the side wall (18) having two holes for receiving the ends of the fastening strips (20) of the chain, the lower wall (56) being held against the bearing surface by the screw (58).

4. The bracelet clasp (1, 100) according to claim 1, wherein the control comprises a pusher (10) movable in a direction substantially perpendicular to a longitudinal direction of the bracelet in response to a user action, the latch (42, 142) being integral with the pusher (10).

5. The bracelet clasp (1, 100) according to claim 4, characterized in that it has an additional control element (10), wherein the control elements (10) are similar and symmetrical about a longitudinal direction of the bracelet, the adjustment device (12, 112) comprising:

an additional latch (42, 142) associated with the additional control (10), wherein the latch (42, 142) is similar and symmetrical with respect to the longitudinal direction of the chain, and

an additional finger (58) associated with the additional latch (42, 142).

6. The bracelet clasp (1, 100) according to claim 5, of the unfolding clasp type, the bracelet clasp (1, 100) comprising at least two strips (2, 4) hinged together, wherein a first strip (2) comprises two posts (8) symmetrical with respect to the longitudinal direction of the bracelet, and said posts are inserted into substantially complementary recesses of a second strip (4) in order to put the bracelet clasp in a closed position by simply bringing the posts (8) closer to each other against the force of an elastic return device (54), wherein the outer edge of each post (8) cooperates with the inner edge of the corresponding recess to define a locking member (38, 40) of the bracelet clasp,

each of said posts (8) carrying one of said pushers (10) and one of said latches (42, 142).

7. The bracelet clasp (1, 100) according to claim 6, wherein each of the posts (8) is made in one piece with the pusher (10) and the corresponding latch (42, 142).

8. The snap clasp (1, 100) according to claim 1, characterized in that the adjustment device (12, 112) comprises at least one elastic element (54, 154), the elastic element (54, 154) exerting a force on the latch (42, 142) in an effort to keep the latch (42, 142) in the closed state.

9. The snap clasp (1, 100) according to claim 8, characterized in that the adjustment device (12, 112) comprises an intermediate member (52, 152), the intermediate member (52, 152) being located in a fixed position with respect to the latch (42, 142) and having a bearing surface for the end of the elastic member (54, 154).

10. The chain shackle (100) as claimed in claim 1, characterised in that the adjustment device (112) further comprises a stud (164), the stud (164) being associated with at least two substantially complementary openings (166) arranged to identify at least two configurations of the adjustment device (112) corresponding to two different available lengths of chain.

11. The shackle (100) as defined by claim 9, wherein the adjustment device (112) further comprises a stud (164), the stud (164) being associated with at least two substantially complementary openings (166) arranged to identify at least two configurations of the adjustment device (112) corresponding to two different available lengths of chain, the stud (164) being carried by the intermediate member (152).

12. The toggle (100) of claim 11, wherein the support structure includes an upper wall (16) and a lower wall (56), the disc portion (44) being disposed between the upper and lower walls, the finger portion (58) taking the form of a screw that secures the upper and lower walls (16, 56) to one another, the opening (166) being disposed on the upper wall of the adjustment device (112).

13. Clasp (100) according to claim 1, wherein the unlocking of the clasp (100) is associated with a displacement of the control member (10) having a first amplitude d1, the unlocking of the adjustment member (14, 16, 56, 58) by the latch (42) being associated with a displacement of the control member (10) having a second amplitude d2, wherein d1 is smaller than d 2.

14. A watch comprising a bracelet on which a bracelet clasp (1, 100) is mounted, the bracelet clasp (1, 100) being of the type comprising a first free end and a second free end, wherein the bracelet clasp comprises:

first and second fastener members (20, 32) of a chain, the fastener members (20, 32) being intended to be formed integrally with a first free end and a second free end of the chain, respectively, wherein the fastener members (20, 32) are movable relative to each other between at least one open position and a closed position for wearing, to close the chain and to determine the usable length of the chain, the fastener members (20, 32) being closer to each other in the closed position than in the open position,

at least one locking member (38, 40), said locking member (38, 40) being arranged to hold said fastener (20, 32) of the chain in a closed position,

at least one control member (10) for the locking member (20, 32), the control member (10) being arranged to unlock the bracelet clasp (1, 100) and move from the closed position to the open position in response to a user action, and

adjustment means (12, 112) for adjusting the usable length of the chain, the adjustment means (12, 112) comprising:

an adjustment member (14, 16, 56, 58), the adjustment member (14, 16, 56, 58) carrying the first fastener (20) of the chain, and

at least one latch (42, 142) capable of having a default closed condition in which the adjustment member (14, 16, 56, 58) is secured, and an open condition in which the adjustment member (14, 16, 56, 58) is free to slide in a chain length direction relative to the second fastener (32) of the chain to change a usable length of the chain,

wherein the adjustment device (12, 112) is separate from the lock (38, 40), the latch (42, 142) being arranged to be moved from a closed state to an open state by a user acting on the control member (10) of the lock (38, 40), so that the adjustment member (14, 16, 56, 58) can be moved independently of the open or closed state of the clasp,

characterized in that the adjustment piece comprises a support structure (14) carrying the first fastener (20) of the chain and at least one finger (58) arranged to cooperate with the latch (42, 142), wherein the latch (42, 142) comprises a disc portion (44), which disc portion (44) adjoins the support structure and is provided with a slot (46) in the radial direction of the chain, wherein the slot (46) has at least two notches (48) which can cooperate with the finger (58) in the closed state of the latch (42, 142) to define respectively two different usable lengths of the chain, the finger (58) being slidable into the slot (46) in the open state of the latch (42, 142) to move from one notch (48) to the other and change the usable length of the chain.