This application claims priority from European Patent Application No. 04028072.9 filed Nov. 26, 2004, the entire disclosure of which is incorporated herein by reference.
The present invention concerns a timepiece, more particularly a wristwatch comprising an interchangeable bezel, i.e. a bezel that can easily be replaced with precise positioning and without any risk of damaging the assembling means.
A certain number of devices that allow a bezel to be replaced by another for aesthetic or functional reasons, particularly in a wristwatch, are already known. For an aesthetic purpose, this for example allows the colour of the most visible part of the watch to be match with that of clothing, at little cost. For a functional purpose, the replacement of the bezel for example allows the indications carried by said bezel to be altered, or the movement to be acted upon in order to have a multi-function watch. EP Patent No. 0 603 353 discloses a watch wherein replacement of the bezel allows the current time display to pass to a “football” or “tennis” mode, the selected bezel then comprising indications relating to such sports and means for controlling the watch mechanism in accordance with the rules of said sports.
According to the known prior art, a removable bezel is set in place and held, or conversely replaced, using devices that can be classified in two large categories, if inconvenient devices, requiring for example screwing, are excluded.
A removable bezel can be fixed by resilient means, as is disclosed in GB Patent No. 286 107. These resilient means can be formed by an elastomeric ring of suitable shape as disclosed in Japanese Utility Model No 4134/78. It may also be a snap fit device as is disclosed in U.S. Pat. No. 5,005,161. In all these resilient assemblies it is difficult to find a good compromise between a device that is sufficiently flexible to allow a user to replace the bezel without any particular effort and a device that is sufficiently secure to prevent it being accidentally lost.
In order to overcome the aforementioned drawback, a certain number of designs propose fixing the bezel to the middle part by means of a so-called “bayonet” device. The device consists in providing in the bezel and in the top part of the middle part or back cover-middle part, complementary male and female means that engage in each other when a movement of rotation is imparted to the bezel. A security system for locking/unlocking the bezel is also generally provided. A design of this type is disclosed in U.S. Pat. No. 5,490,123, the security system being formed by a push-button located on a horn of the case. In EP Patent Application No. 1 249 741, the bayonet device comprises a locking system formed of sinks arranged in the middle part and housing a spring for pushing a ball into recesses made in the inner face of the bezel. These constructions also have the drawback of being relatively complex and having a certain fragility, particularly when the bayonet device is set in place with a rotational movement of the bezel that is too forced and capable of damaging the assembling elements.
It is thus an object of the present invention to overcome the drawbacks of the prior art by allowing a bezel to be easily replaced by another bezel, via a bayonet device, with precise positioning and without any risk of damaging the assembling means.
The invention therefore concerns a timepiece, which will be illustrated hereinafter by a wristwatch with an interchangeable bezel, able to be locked by means of a bayonet device provided on the top part of the middle part of a case closed by a back cover and containing a watch movement for an analogue or digital display of time or non time-related information. The timepiece is characterized in that the shoulder of the middle part is provided with a circular groove and at least two sinks opening partially into said groove. The bezel comprises at least two feet positioned on its inner face to engage in the sinks, said feet each comprising a notch open radially above the emergence of the sinks. These notches form the “male” part of the bayonet device. The “female” part is formed by a locking/unlocking ring placed in the groove, provided with an external rotational manipulation member one edge of which has a substantially equal thickness to the aperture of the notches in the feet, and which comprises recesses for passage of the feet. The other edge of the ring includes an annular gorge facing a gorge formed in a sleeve of the middle part, the two gorges housing a click spring of the ring in the groove, while leaving said ring able to move in rotation.
Thus in order to remove a bezel, one need only rotate the ring with the manipulation member to a position where the recesses in the edge of the ring are positioned exactly above the sinks and release the passage of the bezel feet. To fit a new bezel, the reverse operation has to be carried out, then the locking ring is rotated so that the edge is engaged in the notches of the feet.
To prevent the manipulation member being accidentally moved, the bottom of the groove formed in the shoulder of the middle part is provided with a click spring which cooperates with a boss formed at the base of the locking ring.
The number of feet, and respectively sinks, is at least two. In a preferred embodiment, they are four in number while being arranged in a rectangle, to allow only two possible choices for positioning the bezel, and the feet can either be integral with the bezel or be formed by staples passing through the thickness thereof.
Other features and advantages of the present invention will appear more clearly in the following description of an example embodiment, given by way of illustrative and non-limiting example, with reference to the annexed drawings, in which:
b shows a variant of the bezel;
The invention is described in more detail hereinafter taking, by way of example, a chronograph wristwatch shown in perspective in
As can be seen the watch shown comprises a case 10 formed of a middle part 12 closed by a back cover 13 and by a crystal 8 for housing a chronograph movement 7 (shown in
The construction of the bayonet device is explained now with reference first of all to
Case 10 comprises a middle part 12, in which a watch movement 7 and dial 27 are mounted, closed by a back cover 13 with the insertion of a sealing gasket. The upper shoulder 11 of middle part 12 comprises a circular groove 14, whose edge oriented towards the centre of dial 27 is extended by a sleeve 17. Shoulder 11 also comprises four vertical sinks 15 which open out partially into groove 14, i.e. having an aperture that intersects with an edge of groove 14, which is the outer edge in this example. Sleeve 17 of middle part 12 comprises an annular gorge 16 located above shoulder 11. it can also be seen that shoulder 11 has a recess 8 in an angular sector around 9 o'clock to allow manipulation member 21 to pass. Crystal 8 and sealing gasket 9 are obviously fitted onto the middle part flush with sleeve 17.
Interchangeable bezel 1, shown in
Referring more specifically to
b shows a simplified construction in which bezel 1 only includes two feet 2 integral with the body of bezel 1, i.e. without any staples.
Referring now also to
In order to hold the ring in one or other of the locked/unlocked positions, the wet friction assembly onto sleeve 17 of the middle part may be sufficient. It is however preferable to provide, as is visible in
The preceding description was made with reference to a preferred embodiment, but other alterations can be made by those skilled in the art without departing from the scope of the present invention. It is for example possible to design locking ring 20 with a “mirror image” section and to arrange manipulation member 21 on the back cover of case 10 while giving extension 28 a bent shape to pass through middle part 12 via a slot made in the bottom of groove 14, perpendicularly to the back cover.
Number | Date | Country | Kind |
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04028072.9 | Nov 2004 | EP | regional |