Buckles – buttons – clasps – etc. – Drawstring – laced-fastener – or separate essential... – Having loop or sleeve shaped directing means
Reexamination Certificate
2000-02-02
2001-09-18
Brittain, James R. (Department: 3626)
Buckles, buttons, clasps, etc.
Drawstring, laced-fastener, or separate essential...
Having loop or sleeve shaped directing means
C024S2650WS
Reexamination Certificate
active
06289562
ABSTRACT:
This invention concerns an unfolding clasp for a bracelet, in particular an unfolding clasp for a watch bracelet or watchband.
BACKGROUND OF RELATED ART
Watch bracelets or watchbands are either of the open type or of the closed type. Understood by open-type is one whose two ends can be disunited. The ring formed by the watch and the bracelet can thus be opened to slip on the bracelet. Understood by closed-type is one whose two ends remain integral. Bracelets of the closed type generally comprise an unfolding clasp enabling the diameter to be increased of the ring formed by the bracelet and the watch, so that the hand can pass through. The present invention concerns just such an unfolding clasp for a bracelet or band, in particular one of the closed type.
Different types of unfolding clasps are known, all of which however generally comprise at least two mutually articulated plates as well as a closure. In is closed position, the plates are generally folded up, one on the other, or one next to the other, and are held in this position by an appropriate device. By actuating the closure, the user can release this device to unfold the articulated plates in such a way as to enlarge the opening of the bracelet. The patent documents FR 2 571 228, FR 2 577 120, CH 684 151, CH 678 002 and CH 635 237, for example, describe different types of unfolding clasps for bracelets or bands.
The unfolding of the clasp must be sufficient to allow, in opened position, passage of the hand through the opening of the bracelet, while sufficiently clasping the wrist when in closed position. The common unfolding clasps generally allow the circumference of the bracelet to be varied by about three to six centimeters.
Different constructions have been conceived, with a variable number of plates folding up in diverse ways, which allow such an unfolding to be obtained. The width and the thickness of the plates, however, must be sufficient to ensure reliable functioning of the unfolding clasp, even after a large number of manipulations. The number of articulations is limited, particularly by cost constraints. Moreover, generally desired is that the width of the closure in the closed position allows the closure to be hidden under the bracelet, whereas its thickness must be reduced for reasons of comfort and aesthetics. For all these reasons, the number of usable constructions is limited in actual fact, and all involve relatively long plates. For example, if the clasp is formed by two plates folding up one on the other, the length of the plates in closed position must be at least five centimeters to allow a spreading out of five centimeters in opened position. With three plates folding up in accordion fashion, one on the other, the length of the plates and the clasp in closed position is more than 2.5 centimeters, for example. It is difficult to go beyond three superimposed plates without increasing the thickness of the closure in an unacceptable way.
The length of the unfolding clasp in closed position thus has to be rather large. Consequently, the plates forming the clasp are generally curved to correspond approximately to the curvature of the wrist of the wearer of the watch. The adopted curvature must necessarily be a compromise corresponding to a common wrist size, and thus does not fit very thin wrists or the contrary, wrists wider than average. For this reason, many people are of the opinion that bracelets or bands with unfolding clasps are not very comfortable, and nevertheless prefer the less practical bracelets or bands of the open type.
Telescopic unfolding clasps or those of variable length have been proposed, for example, in CH 668 353 and EP 0 453 635. These devices are however of complex construction and fragile.
SUMMARY OF THE INVENTION
One object of the present invention is to propose an unfolding clasp for a bracelet or band which is improved over the prior art unfolding clasps, in particular a more comfortable unfolding clasp.
This object is attained by means of an unfolding clasp having the features of the characterising part of claim
1
, preferred embodiments being indicated moreover in the dependent claims.
More specifically, this object is achieved by means of an unfolding clasp comprising at least two plates articulated with respect to one another in such a way as to enable adjustment of the opening of the bracelet, wherein the said plates are made of a flexible material able to adopt the shape of the wrist of the wearer of the watch.
Therefore, instead of being made of a rigid material as the majority of prior art unfolding clasps, the unfolding clasp according to the invention is made of a flexible material, for example a plastic, composite or elastic metallic material.
The patent document EP 0 453 635, cited above, already takes an unfolding clasp of plastic material into account. Nevertheless, use of a flexible or elastic material is not mentioned anywhere. Any possible deformation is even prohibited by the large thickness of the unfolding clasp in closed position. Another non-flexible unfolding clasp is described in EP 0 199 708.
One skilled in the art will note that the deformability of the plates of the unfolding clasp facilitates at the same time the passage of the hand through the bracelet when the clasp is unfolded. The extension of the clasp needed for slipping on the bracelet can thus be reduced, which allows use of smaller plates and therefore also increases the comfort.
According to the invention, the plates of the unfolding clasp are deformable in the direction perpendicular to their own plane, so that the curvature of the closed clasp can fit the shape of the wrist. It is however preferable that the plates cannot be deformed in another direction in order too ensure a certain rigidity of the assembly and to prevent the plates of the clasp from going beyond the bracelet in closed position and from becoming visible when they are laterally deformed. According to the invention, the plates of the clasp are thus made of an anisotropic material, i.e. the deformation of the plates caused by a force applied perpendicular to the plane (x, z) containing the said plates is greater than the deformation of the plates caused by an identical force applied in any other direction. The plates can also be made of isotropic elements put together in such a way that the assembled clasp has anisotropic properties.
In a preferred variant of the invention, the plates of the bracelet are made of a composite material.
REFERENCES:
patent: 2394856 (1946-02-01), Hickman
patent: 4178751 (1979-12-01), Liautaud
patent: 4542561 (1985-09-01), Hysek
patent: 4545094 (1985-10-01), Fontana
patent: 4545095 (1985-10-01), Fontana
patent: 5331729 (1994-07-01), Mathieu
patent: 5579559 (1996-12-01), Ferrario
patent: 5689859 (1997-11-01), Cuche
patent: 635 237 A5 (1983-03-01), None
patent: 668 353 A5 (1988-12-01), None
patent: 678 002 A5 (1991-07-01), None
patent: 684 151 A5 (1994-07-01), None
patent: 0 199 708 A2 (1986-10-01), None
patent: 0 344 620 A1 (1989-12-01), None
patent: 0 453 635 A1 (1991-10-01), None
patent: 2 571 228 A1 (1986-04-01), None
patent: 2 577 120 A1 (1986-08-01), None
Linder Stephane
Lipe Thanas
Brittain James R.
Oliff & Berridg,e PLC
Tag Heuer SA
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