EP0843978B1 - Foldable fastener with means for adjusting the length of a bracelet - Google Patents

Abstract

A mechanism for adjusting the length of a bracelet to fit the wrist of the wearer consists of a buckle (40) which pivots about an axis (20) passing through one end of a clasp plate, and a tongue (30) which pivots about the same axis. The tongue or plate end has one or more stops (16) which limit the rotation of the tongue between a raised position at right angles to the plate and a lowered position in the same plane as the plate. In addition, the upper cross-member (46) of the buckle forms a stop for the upper free end of the plate. The buckle's pivot pin (20) is held in place by its ends above the free end of the plate, and the front face of the tongue has a stop (34) which lies at right angles to the pivot pin.

Description

The present invention relates to a folding clasp for flexible bracelet the length of one of the strands of which can be adjusted by means of a mechanism for be adapted to the size of the wearer's wrist. In such clasps, the strand adjustable is connected to a first folding blade by the mechanism using one of the strand adjustment holes, the other fixed strand being connected by a clip at the end of the base blade of the clasp, either directly or through a second blade folding. The blades, also called folding arms, are interconnected by axes of rotation in the manner of hinges.

A first type of mechanism includes a mounted base plate hinged at the end of its folding blade and a section cover transverse in inverted U extending beyond the base plate. The two edges of one hood ends are rotatably mounted on the side faces of the end base plate, the free edges of the other end of the cover lockable by detachable lateral means on the lateral faces from the base plate. The adjustable strand, passing between the base plate and the cover, is held by a protruding stud on the internal face of this base or of the cover when the latter is closed on the plate. Such mechanisms are described, by example, in documents US 1 619 138, CH 631 332, FR 2 699 796 or GB 2,278,148. However, once closed, such mechanisms may appear aesthetically too massive.

A second type of mechanism includes a loop, or loop, of internal cross section slightly greater than that of the strand and which is mounted pivoting on an axis located at the end of the folding blade. This axis can be held in cylinders attached to the end of the blade, the axis or the cylinders constituting, if desired, the lower cross member of the loop. A barb central locking the inside of the loop is also pivotally mounted on the same axis. Once the adjustable strand has passed through the loop, the barb is engaged in one strand adjustment holes, then locked in the loop. This kind of mechanism has the advantage of comprising fewer parts, of being more discreet, and of akin to a belt buckle of known use and a priori simple for the public. However, it is advisable that the barb can on the one hand be retracted during the introduction of the strand into the loop, and that it can also be retained in the buckle to properly hold the adjustable strand to the clasp once it closed and locked.

Document CH 665 536 discloses such a mechanism in which the barb can pivot freely towards the fixed strand, i.e. towards downstream with reference to the direction of insertion of the strand into the loop, for retraction ; but is held back in the transverse plane of the loop by the engagement of its upper end in a housing provided in the face internal of the upper cross member and open downstream. In other words, this upper loop cross member has a lower groove ending in a internal vertical rear wall preventing the barb from tilting further upstream.

GB 2,293,620 also discloses such a mechanism in which the barb can pivot forward. However, in this mechanism, the barb is retained in the front transverse plane of the loop by sound clipping upper end in a spherical cap housing formed in the face internal of the upper cross member of the buckle.

But then, if the length of the bracelet is initially set too large, the user may pull on the adjustable strand to advance it relative to the locked clasp that this user also holds. There is then a risk that the barb tilts forward enough to get out of the hole in the strand it holds momentarily by jamming, but that it subsequently releases without the wearer's knowledge due to vibrations. This risk of untimely exit of the barb out of the strand is even more important when the user just pulls obliquely on this strand to open the clasp. Nothing prevents the strand from moving back and out of the loop thereafter, which can be the cause of the loss of a valuable watch.

The object of the present invention is an improved adjustment mechanism strand in a folding clasp, this mechanism comprising a loop mounted pivoting along an axis of rotation transverse to the end of one of the blades of the clasp as well as a pin mounted pivoting along the same axis as the buckle and suitable to bar the middle of the loop passage. In particular, strand locking adjustable by this mechanism must be particularly solid and reliable whatever are the pull-ups likely to be applied on this strand. Preferably, this mechanism must be composed of a limited number of simple parts to be shaped to reduce the production costs accordingly. This mechanism must also be easy to use and aesthetically discreet.

According to the invention, these objects are achieved because the barb and / or the end of the blade have one or more stops limiting the rotation of this barb between a raised position orthogonal to the end of the blade and a lowered position in line with the blade, and the fact that the cross member upper part of the loop has an underlying front wall capable of come into abutment against the free end of the barb. By front wall is meant a wall on the downstream side of the loop, as seen in relation to the direction of insertion of the strand in the loop.

So when the barb, passing through an opening of the adjustable strand, is raised at the same time as the loop above the end of the folding blade, and that it is folded down and locked on its base blade, we see that strand is held in a particularly reliable way by the clasp. Indeed, if we pulls the strand upstream, the stops preventing rotation of the barb in this direction, the latter retains the strand securely. Conversely, during a traction downstream, it is the front wall which, retaining the end of the barb, retains the strand, even if you pull hard to open the clasp.

On the other hand, to modify the length of the bracelet, simply toggle the buckle and barb forward after opening the clasp, thereby bringing the strand adjustable perpendicular to the end of the blade, then lift effortlessly the barb by taking it out of the first hole to reinsert it in another hole, and fold everything back. The fact that an exit of the barb out of the strand is not possible only after opening the clasp on the one hand and tilting the pin buckle horizontally (so the strand vertically) on the other hand constitutes a large security against an involuntary loss of the watch or the jewel.

In other words, in this mechanism according to the invention, one has reversed the direction of closure of the barb relative to its loop in comparison with the prior art mechanisms mentioned above. This means that the wall of the loop intended to stop the barb can now be on the downstream side, where the traction is greatest when opening the clasp by simply pulling on the strand, the stops ensuring maintenance in the opposite direction.

According to a first embodiment, the axis of the loop is held by lateral shoulders or cylinders under the end of the blade, either in front, either under a notch in the end of the blade, and the barb is extended beyond its axis of rotation by a stop, or other protuberance, equivalent outgrowth.

Then, the front edge of the end of the blade facing the barb prevents it from turning upstream beyond its vertical position orthogonal to the blade, and the underside of the tip of the blade, against which comes to rest the protuberance-stop, prevents this barb from turning downstream beyond from its retracted position in the extension of the blade. For this mode of realization, it is enough to place the opening of passage of the axis to a fifth of the length of the barb from its lower end.

According to a second embodiment, the axis of the loop is held in front the end of the blade or in a notch formed in this end. Then front face of the barb is extended beyond its axis of rotation by a first stop, and its front face has a second stop substantially orthogonal, for example in the form of a protuberance, or a pawn.

Then, the first stop coming to rest against the underside of the tip of the blade prevents the barb from turning downstream beyond its position retracted into the extension of the blade, while the second stop coming leaning on the upper face of the end of the blade prevents it from turning in upstream beyond its orthogonal vertical position for strand locking. This mode However, it requires two stops to be made on the barb. The second stop can be used to facilitate the insertion of the barb in a adjustable strand opening.

According to a third preferred embodiment, the axis of the loop is held by lateral shoulders or cylinders above the end of the blade, and the front face of the barb has a stop, or heel, substantially orthogonal to the axis.

So the lower part of the front side of the barb takes directly support against the upper face of the end of the blade when this barb is in the retracted position, and the front stop of the barb comes to take pressing on the same upper face when this pin is in the raised position of buckle lock. In practice, this form of wedge barb turns out relatively simple to machine, and the rear stop is also a grip point for the user's nail when he wants to push the barb into a hole in the strand adjustable.

It should be noted that the clasp structures described previously lend themselves not only to metal fabrication of conventional manner, but also to mass production by molding of thermoplastic material.

Advantageously, the internal face of the upper cross member of the loop has a clipping recess at the free end of the barb just behind the wall frontal. Advantageously then, the barb is made of a material accepting a elastic deformation to facilitate its engagement in the hollow, therefore its clipping. This material can be a spring steel or a polymer.

This possibility of clipping the barb in the loop gives a part better rigidity to this mechanism in the locked state, and on the other hand frank and audible indication of the correct installation of the barb in the loop after the strand has been inserted.

According to an advantageous embodiment, the loop is formed of a U-shaped cover associated with an axis of rotation held by cylinders or side walls integral with the end of the folding blade.

This reduces the number of parts making up the mechanism, these parts being either available on the market or easy to machine.

Usefully, the loop with its frond wall and its clipping hollow or other complementary forms for locking the barb in the buckle are produced by an injection process of plastic or metal powder (MIM).

• la figure 1 est une vue en perspective d'un premier mode de réalisation d'un mécanisme de réglage de longueur de brin selon l'invention,
• la figure 2 est vue en coupe longitudinale du mécanisme de la figure 1 monté sur un fermoir dépliant,
• les figures 3a à 3k sont des vues en coupe longitudinale du mécanisme de la figure 1 lors de différentes étapes d'utilisation,
• la figure 4 est une vue en coupe longitudinale d'un second mode de réalisation d'un mécanisme selon l'invention, et
• la figure 5 est une vue en coupe longitudinale d'un troisième mode de réalisation d'un mécanisme selon l'invention.

The invention will be better understood from the study of embodiments taken without any limitation being implied and illustrated in the appended figures in which:

• FIG. 1 is a perspective view of a first embodiment of a strand length adjustment mechanism according to the invention,
• FIG. 2 is a view in longitudinal section of the mechanism of FIG. 1 mounted on a folding clasp,
• FIGS. 3a to 3k are views in longitudinal section of the mechanism of FIG. 1 during different stages of use,
• FIG. 4 is a view in longitudinal section of a second embodiment of a mechanism according to the invention, and
• Figure 5 is a longitudinal sectional view of a third embodiment of a mechanism according to the invention.

As illustrated in FIG. 2, a clasp for a flexible bracelet, namely leather, plastic or wire mesh, includes a folding top blade 1 articulated at one of its ends by a hinge 9 at the end corresponding to a base blade 2. The other end of the folding blade 1 can be hung and unhooked at will at the other end corresponding to base blade 2. For example and as illustrated, the end free front of this folding blade has a groove 12 in which comes engage a hook 13 secured to the upper face of the base blade. A such clasp allows to join in one of their ends the two strands 4, 5 of a bracelet, the other two ends being connected to a watch or a piece of jewelry. More specifically, a so-called fixed strand 4 is connected by a fastener to the free end of the base blade 2 (i.e. the end opposite to that of the hinge 9), while the other strand 5 said adjustable is connected to the free end of the folding blade 1 by a mechanism adjustment of the length of the bracelet including a buckle 40 associated with a pin 30.

As best seen in Figure 1, the free end 10 of the blade folding present, little behind the hooking groove 12, two lateral cylinders fastening 14 arranged above the upper surface 16, or base, of this end 10.

To these fixing cylinders is attached a pivoting loop 40 which, as illustrated, is formed by a U-shaped cover 42 comprising a cross-member upper 43 and two lateral branches 44 whose lower edges are articulated at the ends of a fixed axis of rotation 20 driven forcibly into the cylinders of attachment 14, this axis of rotation constituting the lower cross member of the loop 40. In particular, this axis 20 is engaged by end pieces of axis 22 of reduced diameter, on either side in the lower edges of the lateral branches 44. This reduction in diameter ensures that the U-shaped cover remains aligned with the axis.

More particularly according to the invention, the crosspiece 43 has a wall vertical 46 at its lower front edge, that is to say its downstream edge such that considered with respect to the direction of introduction of the adjustable strand, which in the case of the Figure 1, is done from right to left. The height of this front wall vertical 46 is between 1/10 and 1/3 of the height of the lateral branch 44.

Conversely, the upstream lower edge of the crosspiece 43 is under the shape of a horizontal or slightly oblique face 45 of small angle of attack, that is to say of the order of 2 to 20 degrees from the horizontal and oriented towards outside. The central part of this underside of crosspiece 43 has, in its middle, a clipping housing 47 separated from the oblique upstream face 45 by a entry bead 48. For example, this clipping housing can be produced by drilling. Alternatively, this housing 47 and this bead 48 are machined over the entire width of the cross member, that is to say from one side branch 44 to the other. Of preferably, all of this loop 40 is injection molded with metal according to a technique called MIM.

Associated with this loop 40, this adjustment mechanism comprises also a pin 30 mounted on the axis of rotation 20 between the two cylinders of lateral fixing 14. The height of this barb 30 is such that its end free top is designed to snap into the clip-on housing 47 after having exceeded the entry bead 48 following either a slight deformation towards the top of the cross-member 43, but preferably following a slight bending of this barb, the latter being made of a material having a relative elasticity.

More particularly according to the invention, this barb 30 has a heel stop 34 oriented upstream and located at the axis of rotation 20. This heel stop 34 forms, on either side of the barb 30, cylinders 32 of overlap of the axis of rotation 20. As illustrated, this heel stop 34 is provided to come to rest flat on the upper face 16, or base, of the end of the blade 10, when the barb 30 is oriented vertically, its free end being engaged in the housing 47 of the loop.

How to use the arm length adjustment mechanism 5 described previously in relation to FIGS. 1 and 2 will now be explained with reference to Figures 3a to 3k.

To open the mechanism in order to insert the adjustable strand, it is advisable first open the clasp, which allows the buckle to be switched only afterwards 40 and the barb 30 clipped forward in a downstream rotation (a), as illustrated on the Figure 3a. After a rotation (a) of a quarter turn, the front face of the barb 30 comes into abutment flat against the upper face 16 of the blade, this close to the groove 12. Then, by forcing on the loop 40, one can induce a rotation additional of this (b), which makes it possible to easily release the free end of the barb 30 out of the housing 47 of the loop as illustrated in FIG. 3b. he then simply raise the barb vertically, for example by acting with the nail on the heel stop 34 by exerting a pressure (c) as illustrated in FIG. 3c. The passage of the loop 40 being free, one can then insert the adjustable arm 5 according to a vertical translation (d).

Two methods allow the adjustable strand to be locked in the mechanism. According to the first method illustrated in Figures 3d to 3f, we begins by engaging the end of the barb 30 in one of the holes in the strand by rotating downstream with a rotation (e), for example by inserting the nail under the heel stop 34 which can thus be lifted. With reference to Figure 3e, it suffices then pull firmly on the strand (f) so that it drives the barb according to a always rotate downstream (g) until its end is clipped into the internal housing 47 of the loop. It then suffices to turn the strand and the buckle with its barb clipped a quarter turn upstream (h), which brings the stop 34 bearing on the upper face of the blade, this position illustrated by the Figure 3f allowing only then to close this clasp by engaging the groove 12 in the hook 13 of the base blade 2.

The second method, illustrated in Figures 3d to 3f, also consists in pre-engage the free end of the barb in one of the holes of the strand in a downstream rotation (e ') acting with the nail under the heel stop 34 according to Figure 3g. The next step, unlike the previous process, consists to raise the loop-pin-strand assembly by a first rotation (h) upstream until bringing the heel stop 34 of the barb 30 to bear on the upper face of the blade as illustrated in Figure 3h. So just force the rotation complementary upstream (H) of the loop, until bringing its cross upper above the barb itself blocked in rotation by the support of its stop, and this until the free end of this barb engages in the housing 47 as illustrated in FIG. 3i.

It should be noted that the user is informed of the correct engagement of the barb in the loop during the steps of Figures 3e and 3i when it hears a "click" noise and feels effective resistance.

When the clasp is locked as illustrated in Figure 2, we then notes that a traction exerted downstream on the strand 5 is compensated by the reaction of the front wall 46 of the loop 40 on the upper end of the barb 30. Conversely, an upstream traction exerted on the adjustable strand 5 inducing a torque of upstream rotation at the barb 30 is compensated by the support of the heel stop 34 on the upper face of the end of the blade 1, this support creating a resistive torque in reverse.

To change the length of the bracelet, first open the clasp then to switch back the adjustable strand and the buckle containing the barb towards the front according to a rotation (I) of FIG. 3j, the heel stop of the barb being found then vertically. So by holding the loop on the one hand, we exercise on the other hand a traction (m) on the upstream part of the strand, which causes a disengagement of the barb outside the loop by a rotation (n) according to Figure 3k. After having selected the new desired strand orifice, we close the mechanism according to one of the processes described with reference to Figures 3d-3f or 3g-3i.

The invention is not strictly limited to the embodiment described previously, but encompasses many variations.

According to a second embodiment illustrated in FIG. 4, the axis 20 of the barb 30 'can be located in the thickness of the end of the folding blade 1, the base of the barb then being housed in a middle notch 3 formed in this end of the blade. Then, the anterior (upstream) face of the barb 30 'is complete with a rear heel stop 34 'located slightly above the axis of rotation 20 to, as before, come to bear on the upper face of the end of the blade once this barb is raised vertically, i.e. orthogonally to this end. This 30 'barb also includes a second stop 35 extending the front face and capable of coming to bear against the underside of the end of the blade 1, once this barb has been tilted a quarter turn downstream and is therefore found directly in the extension of this blade. In this variant, it is just necessary to provide a drilling in the middle of the base blade 2, slightly upstream of its hook 13 for accommodate the stopper 35 when the clasp is locked as illustrated.

According to a third embodiment illustrated in FIG. 5, the axis 20 can be held below the end of the folding blade 1 on both sides by lateral shoulders 8 integral with the blade, the loop 40 still being articulated on this same axis 20. Then, the barb 30 "is offset downward relative to to its axis 20 to reveal a lower stop 35 ". This barb 30" vertically crosses a central notch 3 formed in the middle of the end of the folding blade 1. To accommodate this arrangement, there is then provided a opening 6 "in the middle of base blade 2 slightly upstream of its hook 12" associated with a rounded end 13 "of the folding blade 1. This arrangement is approximates to that described in document GB 2 293 620 apart from the fact that the barb has a bottom heel stop 35 "and the fact that the buckle 40 has here a vertical stop wall 46 front.

As can easily be understood, the 30 "barb is then retained in upstream rotation beyond its vertical position by its support against the edge front at the bottom of the notch 3. Furthermore, this barb 30 "is retained in rotation downstream beyond its horizontal position by the support of the bottom stop 35 "against the underside of the end of the folding blade 1.

The variant embodiments can be produced either in pieces of machined metal, either plastic injection molded parts. Although these mechanisms do not have more parts than those known previously, the mechanism according to the invention proves to be particularly rigid and reliable once closed.

Claims (8)

1. Folding clasp (1,2) for bracelets with a strand adjusting mechanism (5), this mechanism comprising a buckle (40) mounted pivotally round a transverse rotational shaft (20) at the end of one of the blades (1) of the clasp as well as a tongue (30) mounted pivotally round the same shaft (20) as the buckle, wherein the tongue and/or the end of the blade have one or more stops (16,34) limiting the rotation of this tongue between a raised position orthogonal to the end of the blade and a lowered position in the extension of the blade, and wherein the upper cross bar of the buckle has a subjacent front wall (46) capable of abutting against the free end of the tongue.
2. Clasp according to claim 1, wherein the shaft (20) of the buckle is held by lateral shoulders or cylinders (14) above the end (16) of the blade and wherein the anterior face of the tongue (30) has a substantially orthogonal stop (34) in the region of the shaft.
3. Clasp according to claim 1, wherein the shaft (20) of the buckle (40) is held in front of the end of the blade or in a notch (3) provided in this end, wherein the front face of the tongue (30) is extended beyond its rotational shaft by a first stop (35) and wherein its anterior face has a substantially orthogonal second stop (34').
4. Clasp according to claim 1, wherein the shaft (20) of the buckle (40) is held by lateral shoulders or cylinders (8) beneath the end of the blade (1) either in front of or beneath a notch (3) provided in the end of the blade and wherein the tongue (30") is extended beyond its rotational shaft by a stop (35").
5. Clasp according to any one of the preceding claims, wherein the internal face of the upper cross bar (43) of the buckle (40) has a depression (47) for latching the free end of the tongue (30) just behind the front wall (46).
6. Clasp according to any one of the preceding claims, wherein the buckle is formed by a U-shaped cap (42) associated with the rotational shaft (20).
7. Clasp according to claim 5 or 6, wherein the tongue is produced from an elastic material.
8. Clasp according to claim 5 or 6, wherein the buckle is produced by a method involving injection of plastics material or metal powder (MIM).

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