US20250268343A1

US20250268343A1 - Adjustable bracelet clasp

Info

Publication number: US20250268343A1
Application number: US19/044,794
Authority: US
Inventors: Philipp Tschumi; Gregory LORIOL
Original assignee: Compagnie des Montres Longines Francillon SA
Current assignee: Compagnie des Montres Longines Francillon SA
Priority date: 2024-02-23
Filing date: 2025-02-04
Publication date: 2025-08-28
Also published as: JP2025129131A; CN120531221A; EP4606253A1

Abstract

A clasp for a folding-clasp bracelet, the clasp including a cover to which at least a first blade and a second blade are attached, which blades are hinged together and to which blades a first bracelet strand is attached; a first locking mechanism for holding the blades in the closed position on the cover; an actuator including a first and a second push-pieces; a mechanism for adjusting the length of the bracelet, to which a second bracelet strand is attached. The length adjustment mechanism include an end piece sliding inside the cover, the sliding end piece having a toothed sector arranged to cooperate with a second locking mechanism controlled by a push-piece.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a bracelet clasp of the folding type, which allows the effective length of the bracelet to be adjusted.
The present invention further relates to a wristwatch provided with such a clasp.

PRIOR ART

The issue regarding the need to provide a device for adjusting the effective length of a bracelet is well known.
On the one hand, in the case of bracelets made up of links, it is possible for the wearer's wrist to have a circumference whose value lies between two configurations of the bracelet that differ from each other by one link only. There is thus an advantage to providing a device for adjusting the effective length of the bracelet, allowing the length of the bracelet to be adjusted more finely than by removing or adding a link.
We also know that the value of the wrist circumference varies with the seasons, with a maximum value typically being reached in summer and a minimum in winter. The circumference of the wrist can also vary depending on the time of day. Again, it is preferable to provide a device for finely adjusting the effective length of the bracelet, allowing the wearer of the bracelet to adjust this length to improve the comfort of the bracelet when worn.
For example, patent EP 0 350 785 B1 describes a clasp comprising a device for adjusting the effective length of the bracelet, which device can be operated without tools. The clasp described in this patent is of the folding type and comprises two blades hinged together by means of a rod passing through both of them, each of the blades carrying, at its free end, an attachment member for attachment to a bracelet. A first blade carries a hook intended to engage in a hole made in the second blade to cooperate with a bolt allowing the hook, and thus the clasp, to be locked in a closed state. The second blade comprises two parts capable of sliding relative to each other within a certain predefined range, defining a pitch for adjusting the effective length of the bracelet. A first of its two parts carries the hinge connecting it to the first blade, whereas the second part carries the locking bolt. The hole in which the hook engages to lock the clasp has a length, in the longitudinal direction of the bracelet, corresponding to the sliding range between the two parts of the second blade. The bolt has a central part defining two positions for the hook, in the longitudinal direction of the bracelet, corresponding to two different effective lengths of the bracelet. A control member comprising a push-piece actuates the bolt to release the hook and open the clasp.
One drawback of this structure is that the adjustment to the length of the bracelet is lost each time the clasp is opened. As a result, each time the clasp is closed, the wearer of the bracelet must ensure that the hook is inserted on the central portion side of the bolt corresponding to the desired length of the bracelet.
Alternatively, adjustment devices comprising a specific locking member have also been proposed to avoid drawbacks of this type.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the aforementioned and other drawbacks by providing a clasp for finely adjusting the length of a watch bracelet which, on the one hand, allows the adjustment of the length of the bracelet to be kept without the risk of inadvertently losing same and, on the other hand, provides for particularly simple and fast adjustment and handling.
To this end, the present invention relates to a clasp for a folding-clasp bracelet, the clasp comprising:

- a cover to which at least a first blade and a second blade are attached, which blades are hinged together and to which blades a first bracelet strand is attached;
- first locking means for holding the blades in the closed position on the cover;
- actuating means comprising a first and a second push-pieces;
- means for adjusting the length of the bracelet, to which a second bracelet strand is attached.

According to the invention, the length adjustment means comprise an end piece sliding in the cover, the sliding end piece having a toothed sector arranged to cooperate with second locking means controlled by a push-piece, the sliding end piece being arranged to move from a locked position to an unlocked position in which the end piece is completely disengaged from the cover.
According to other advantageous alternative embodiments of the invention:

- the locking means comprise a lever pivoting between a locked position and an unlocked position, the lever having a first end arranged to cooperate with one of the push-pieces and a second end having a toothed element arranged to cooperate with the toothed sector of the sliding end piece;
- the locking means comprise elastic return means for holding the lever in the locked position;
- the cover has an overall U-shaped cross-section and is provided with two wings facing each other, each of these wings having an opening to receive the first and second push-pieces;
- the push-pieces have a body and a head, the head of each push-piece resting inside one of the openings and one of the heads being arranged to cooperate with the first end of the lever;
- the body of the push-pieces carries the first locking means of the clasp, the length of the body of each push-piece being predefined in such a way that when the push-pieces are actuated simultaneously, the body of the push-pieces comes into contact and does not disengage the lever;
- the clasp comprises a plate integral with the cover to form a recess between the plate and the cover, the plate having two openings through which the first locking means pass;
- the cover comprises a cavity arranged to receive a spring, the spring cooperating with the sliding end piece;
- the sliding end piece has a machined shape complementary to the shape of the cavity;
- the clasp comprises stop means preventing the sliding end piece from dislodging from the cover;
- the toothed sector has a plurality of teeth, each tooth defining an indexed position of the sliding end piece;
- the toothed sector comprises teeth of asymmetrical shape, such that a first portion of the tooth is perpendicular to the direction of movement of the sliding end piece, and the second portion of the tooth has a slope;
- the toothed element of the lever has a shape complementary to the asymmetrical shape of the teeth of the toothed sector.

BRIEF DESCRIPTION OF THE FIGURES

Other features and advantages of the present invention will appear more clearly upon reading the following detailed description of one embodiment of the clasp for a watch bracelet or for a belt according to the invention, this example being provided for the purposes of illustration only and not intended to limit the scope of the invention, given with reference to the accompanying drawing, wherein:

- FIGS. 1 a and 1 b are exploded perspective views of the clasp according to the invention;
- FIG. 2 is a perspective view of the clasp of FIG. 1 in the assembled state;
- FIG. 3 is a perspective, bottom view of the clasp according to the invention, with the adjustment link in the engaged position;
- FIG. 4 is a cross-sectional view of the clasp according to the invention, with the fine adjustment link in the disengaged position.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described with reference to a watch bracelet. However, it goes without saying that this example is given for the purposes of illustration only and is non-limiting, and that the clasp according to the invention can also be used for a belt buckle for example.
FIGS. 1 a and 1 b are exploded perspective views of the clasp according to the invention, whereas FIG. 2 is a perspective view of the same clasp in the assembled state. The clasp 1 according to the invention comprises a cover 2, connected on a first side to a first bracelet strand (not shown), with the insertion of a folding-clasp fastening system 20 and first clasp locking means 30, 31, the structures whereof are known and will thus not be described further here, which folding-clasp fastening system can comprise two or three blades. The cover 2 is connected on a second side to a second bracelet strand (not shown), with a sliding end piece 10 for the fine adjustment of the length of the bracelet of the watch. The bracelet strands can be formed by a succession of links or by a strand made of leather, fabric or even an elastomer material.
As shown in FIG. 1 , the cover 2 has an overall U-shaped cross-section and is provided with two wings 12 facing one another, these wings 12 having an opening 14 on each of their faces for receiving a push-piece 4, 5. Moreover, a cavity 16 is made in the bottom of the cover 2 and defines a receptacle for a spring 18, the role whereof will be described in detail hereinbelow.
The sliding end piece 10 comprises guide means for slidingly guiding it in the cover 2, these guide means being formed by a groove 11 machined in the bottom of the cover 2 and cooperating with the cavity 16 to guide the end piece 10 in the cover 2, the groove and the cavity being coaxial.
The sliding end piece 10 comprises a catch 13 intended to slide in the groove 11 in the cover 2 and guide the end piece 10 as it moves translatably. The length of the groove 11 both defines the length of travel of the end piece 10 relative to the cover 2 and forms a stop for the end of travel of the end piece 10 when the catch 13 reaches the end of the groove 11. It can also be seen from the figures that the end piece 10 has a machining 17 complementary in shape to the cavity 16 to provide an additional guide means, which makes it possible to limit the play of the end piece 10 once it has been mounted inside the cover 2.
Thus, the sliding end piece 10 is able to slide in a longitudinal direction of the clasp 1 between a first position wherein the sliding end piece 10 is engaged in the cover 2 of the clasp 1, and at least one second position wherein the sliding end piece 10 is completely disengaged from the cover 2 of the clasp 1. The length available for adjusting the bracelet is determined by the travel of the sliding end piece 10.
The clasp 1 comprises length adjustment means formed by the sliding end piece 10 which moves in the cover 2. According to one embodiment of the invention, the fastener comprises a closure element in the form of a plate 3 integral with the cover 2 to form a recess between the plate 3 and the cover 2, the end piece sliding within this recess. Advantageously, the plate 3 has two openings 32, 33 through which the first locking means 30, 31 pass. Such a configuration thus prevents foreign bodies from becoming lodged in the cover and preventing the clasp from operating correctly.
The end piece 10 has a toothed sector 15 arranged to cooperate with second locking means controlled by one of the push-pieces 4, 5, so as to lock or unlock it in order to adjust the length of the clasp.
As can be seen in FIGS. 1 a, 1 b and 3, the second locking means take the form of a lever 6 pivoting between a locked position and an unlocked position. The lever 6 is pivotally mounted on a lug 63, the lever 6 having a first end 60 arranged to cooperate with one of the push-pieces 4, 5 and a second end 61 having a toothed element 62 arranged to cooperate with the toothed sector 15 of the sliding end piece 10.
The toothed element 62 is arranged to cooperate with the toothed sector 15 so as to lock the sliding end piece 10 in the adjustment position chosen by the wearer, the toothed sector 15 having at least two teeth 150, 151 to form at least two positions. A person skilled in the art will obviously have no particular difficulty in adding a plurality of teeth to form a plurality of length adjustment positions.
The toothed element 62 is formed in the first portion of the lever 6 by machining, for example, and has dimensions close to those of the teeth of the toothed sector.
The lever 6 is arranged to move from a first position, referred to as the rest position, wherein the toothed element 62 is engaged with a tooth of the toothed sector 15, to a second position wherein the toothed element 62 is released from its engagement with the toothed sector 15.
The locking means further comprise elastic return means for holding the lever 6 in the locked position. These elastic return means take the form of a torsion spring 7 articulated about the axis of rotation of the lever, a first portion 71 of the spring being attached to the cover and a second portion 72 constraining the lever 6 in its rest position.
According to the invention, the toothed sector 15 comprises teeth 150, 151, 152, 153 of asymmetrical shape, such that a first portion of each tooth is perpendicular to the direction of movement of the sliding end piece 10, and the second portion of each tooth has a slope.
The toothed element 62 of the lever 6 has a shape complementary to the asymmetrical shape of the teeth of the toothed sector, such that the sliding end piece 10 is blocked by the lever when the wearer pulls on the bracelet strand attached to the end piece without having to first unlock the lever. However, thanks to the geometry of the teeth, the wearer can shorten the length of the bracelet without having to unlock the sliding end piece 10.
As can be seen in FIG. 3 , the cover 2 comprises a cavity 16 of substantially parallelepipedal shape, in which the spring 18 is disposed, this spring being compressed between the bottom of the cavity 16 and the bottom of the machining 17 of the end piece 10. It is understood that when the sliding end piece 10 is assembled in the cover 2, the spring 18 is compressed between the cavity and the sliding end piece 10, which forces the end piece to disengage from the cover 2 when the lever 6 is unlocked by the wearer.
When the end piece 10 is unlocked when the wearer presses the push-piece, the lever 6 disengages from the toothed sector 15 and releases the end piece 10, which slides into the recess and is completely disengaged from the cover 2 under the action of the spring. Once the end piece is fully disengaged from the cover, the wearer can adjust the length of the clasp while keeping it on the wrist. The wording “is completely disengaged from the cover 2” is understood to mean that the end piece 10 reaches the furthest position allowed by the length of travel while remaining rigidly connected to the cover.
On each side of the cover 2, close to the end through which the end piece 10 slides, retaining means 19 are machined to limit the travel of the end piece 10 and prevent it from being completely extracted from the cover 2 once the clasp 1 has been assembled.
The push-pieces 4, 5 have a body 40, 50 and a head 41, 51, the head of each push-piece resting inside one of the openings in the cover 2 and one of the heads 41, 51 being arranged to cooperate with the first end 60 of the lever 6 in order to unlock the end piece 10. The push-pieces are held in their rest position by means of a pair of springs 8, each of the ends of the springs being housed in a blind hole formed in the head of the push-pieces.
The bodies 40, 50 of the push-pieces carry the first locking means 30, 31, in this case hooks arranged to cooperate with the blades of the folding clasp. Advantageously, the body of each push-piece 4, 5 has a predefined length so that when the push-pieces 4, 5 are actuated simultaneously by the wearer, the bodies of the push-pieces come into contact (or abutment) and do not disengage the lever 6. The length of the bodies of the push-pieces thus makes it possible to define the length of travel thereof in order to prevent the wearer from unintentionally modifying the adjustment when opening the clasp.
To adjust the clasp, the user presses the push-piece located near the lever 6, so that the head of the push-piece presses against the first end 60 of the lever 6 to pivot the latter and disengage the toothed element 62 from the toothed sector 15.
Once the toothed element 62 is disengaged, the sliding end piece 10 is free to move translatably until it abuts under the action of the spring 18, the end piece then being completely disengaged from the cover and the user can release the push-piece.
Finally, to adjust the desired bracelet length, the user handles the bracelet strand attached to the movable end piece 10 to partially retract the latter into the cover 2 in the desired position, the association of the toothed element 62 with the toothed sector 15 forming a disengageable click and allowing the user to feel the transition from one tooth to the next during adjustment.
It goes without saying that the present invention is not limited to the embodiment described above and that various simple alternatives and amendments could be considered by a person skilled in the art without leaving the scope of the invention as defined by the accompanying claims.

Claims

1. A clasp for a folding-clasp bracelet, the clasp comprising:

a cover to which at least a first blade and a second blade are attached, which blades are hinged together and to which blades a first bracelet strand is attached;

first locking means for holding the blades in the closed position on the cover;

actuating means comprising a first and a second push-pieces;

means for adjusting the length of the bracelet, to which a second bracelet strand is attached;

wherein the length adjustment means comprise an end piece sliding in a recess formed in the cover, the sliding end piece having a toothed sector arranged to cooperate with second locking means controlled by a push-piece, the end piece being arranged to move from a locked position to an unlocked position in which the sliding end piece is completely disengaged from the cover.

2. The clasp according to claim 1, wherein the locking means comprise a lever pivoting between a locked position and an unlocked position, the lever having a first end arranged to cooperate with one of the push-pieces and a second end having a toothed element arranged to cooperate with the toothed sector of the sliding end piece.

3. The clasp according to claim 1, wherein the locking means comprise elastic return means for holding the lever in the locked position.

4. The clasp according to claim 1, wherein the cover has an overall U-shaped cross-section and is provided with two wings facing each other, each of these wings having an opening to receive the first and second push-pieces.

5. The clasp according to claim 1, wherein the push-pieces have a body and a head, the head of each push-piece resting inside one of the openings and one of the heads being arranged to cooperate with the first end of the lever.

6. The clasp according to claim 1, wherein the body of the push-pieces carries the first locking means of the clasp, the length of the body of each push-piece being predefined in such a way that when the push-pieces are actuated simultaneously, the body of the push-pieces comes into contact and does not disengage the lever.

7. The clasp according to claim 1, wherein the clasp comprises a plate integral with the cover to form a recess between the plate and the cover, the plate having two openings through which the first locking means pass.

8. The clasp according to claim 1, wherein the cover comprises a cavity arranged to receive a spring, the spring cooperating with the sliding end piece.

9. The clasp according to claim 4, wherein the sliding end piece has a machining whose shape complements to the shape of the cavity.

10. The clasp according to claim 1, wherein the clasp comprises stop means preventing the sliding end piece from dislodging from the cover.

11. The clasp according to claim 1, wherein the toothed sector has a plurality of teeth, each tooth defining an indexed position of the sliding end piece.

12. The clasp according to claim 1, wherein the toothed sector comprises teeth of asymmetrical shape, such that a first portion of the tooth is perpendicular to the direction of movement of the sliding end piece, and the second portion of the tooth has a slope.

13. The clasp according to claim 11, wherein the toothed element of the lever has a shape complementary to the asymmetrical shape of the teeth of the toothed sector.