Patent Description:
Document <CIT> discloses a quick release system according to the preamble of claim <NUM>.

Quick release systems for watch straps have enjoyed increasing popularity in recent years.

They allow the wearer of the watch to change the strap on a watch easily and without tools. In addition to changing the strap on the watch head, the tool-free change of the strap on the clasp is also desirable. A quick-change system on this enables the customer to use different straps, for example made of leather, rubber or textile, with the same clasp. This is particularly, but not exclusively, of interest for the area of "Haute Horlogerie". In the "Haute Horlogerie" complex and expensive folding clasps are widely used, some of them made of precious metal. Interchangeability of the strap on the clasp is therefore of particular importance in this area.

A common system for changing a strap on a folding clasp comprises a spring bar that has a protruding pin. By pulling the pin with the fingernail, the pin if the spring bar is pulled out of the counterpart, which releases the band. However, this system can hardly meet the requirements of "Haute Horlogerie". Plus, the use of a spring bar limits the implementation of a locking system.

In contrast to this, the present invention aims at a system, which meets high demands in term of functionality and ease of use.

It is an object of the invention to overcome these drawbacks in proposing a quick-release system which is easy to use and in which the locking element is subjected to little stress and which offers a high level of security. An invisible fastening in the assembled state and a low height requirement are also to be made possible.

Hence, the invention relates to a quick release system for an interchangeable watch strap comprising:.

According to other features of the invention:.

Thus, the invention offers a high level of operating comfort and can meet the requirements of demanding customers. The presented system can be used with different folding clasps, and it is conceivable to replace the connection element for the strap in an existing folding clasp with the present invention. An existing folding clasp can be converted into a folding clasp with a quick-change system with little effort.

Another advantage of the invention is that no mechanisms are necessary in the strap itself. Since straps, in particular made of leather, are wearing parts which should be changed at regular intervals for hygienic and aesthetic reasons, it is desirable to make them as simple as possible. This reduces the manufacturing effort and thus also the price of the strap and increases flexibility.

Other features and advantages of the present invention will appear more clearly upon reading the following detailed description, made with reference to the annexed drawings, given by way of non-limiting and in with:.

The invention will now be described in detail with reference to the attached drawings illustrating, by way of example, an embodiment of the invention.

The invention proposes to give the user the possibility of easily and securely changing the wristband fitted to his/her watch while keeping the same clasp with the least possible handling, and also proposes a watch with interchangeable wristband for the lowest possible differential production cost.

It must be possible to change the wristband without any tool and without delicate handling while allowing a fast change between a leather wristband and a linked metal wristband, for example, or also allowing the wristband to be matched to items of clothing and/or jewellery worn by the user or to the complexion of the user, in accordance with the circumstances of use of the watch. The interchangeable wristband also enables wristbands of different length to be exchanged instantaneously, which allows retailers and dealers to immediately supply their customers with perfectly suited watches.

The invention thus preferably relates to a quick release system for an interchangeable watch strap <NUM> on a clasp <NUM>.

According to the invention, the quick release system comprises:.

Advantageously, the first lateral end piece <NUM> has a milling contour that is complementary to the connector of the clasp <NUM>. Such assembly limits the movement of the first lateral end piece <NUM> in the plane of the end link. By plane of the end link, we consider a plane extending longitudinally along the end link <NUM>.

As shown on <FIG> and <FIG>, the first lateral end piece <NUM> comprises an first bar <NUM>, which is arranged to be connected to the strap <NUM>.

The mobile end piece <NUM> comprises a complementary bore to receive the free end <NUM> of the first bar <NUM>. The length of the first bar <NUM> is dimensioned so that the free end <NUM> is released when the mobile end piece <NUM> is pulled away from the body <NUM> in its unlocked position, thus enabling the mobile end piece <NUM> to rotate and enabling the user to remove the strap. In locked position, the free end <NUM> of the first bar <NUM> is fitted into the bore <NUM> and prevent the mobile end piece <NUM> from rotating around the retaining stem <NUM>.

The first lateral end piece <NUM> is connected radially to the clasp <NUM> by the second bar <NUM>. This second bar <NUM>, designed as a screw in the variant shown on figures, can move in an axial direction parallel to a longitudinal axis of said second bar <NUM>, within the first lateral end piece <NUM>.

The first end <NUM> of the second bar <NUM> comprises a head <NUM> and a body <NUM>, the head <NUM> having a diameter D1 larger than the diameter D2 of the body <NUM> of the second bar <NUM>.

As can be seen on <FIG>, the first lateral end piece <NUM> comprises a stepped bore <NUM> which goes through it and provides a stop for the first end <NUM> of the second bar <NUM>. The head <NUM> of the first end <NUM> of the second bar <NUM> is sliding into the stepped bore <NUM> of the first lateral end piece <NUM>, the stepped bore <NUM> comprising a first portion of a diameter D3 and a second portion of diameter D4. The diameter D3 of the first portion is larger than diameter D4, and the diameter D1 of the head <NUM> is slightly smaller than the diameter D3 of the first portion of the stepped bore <NUM> and slightly bigger than diameter D4 of the second portion of the stepped bore <NUM>, so that the second bar <NUM> can slide inside the stepped bore <NUM> and be stopped by the stepped bore <NUM>.

Advantageously, the length of the stepped bore <NUM> determines the stroke of the first end of the second bar <NUM> inside the stepped bore <NUM>.

According to the invention, the mobile end piece <NUM> is firmly connected to the second bar <NUM> via its second end <NUM> to the retaining stem <NUM>. In the variant shown, the retaining stem <NUM> is fixed to the second end <NUM> of the second bar <NUM> by means of a thread. However, other types of connection are also conceivable, for example a press connection. Thanks to this arrangement, the retaining stem <NUM> and the second bar <NUM>, and implicitly the mobile end piece <NUM>, are able to rotate in relation to the body <NUM> around the axis of the second bar <NUM>. Such an arrangement simplifies the maintenance operation when needed too, the operator only need to unscrew the mobile end piece from the second bar <NUM>.

Thanks to this arrangement, the mobile end piece <NUM> is limited in an axial direction parallel to a longitudinal axis of said second bar <NUM> or retaining stem <NUM> (which is the same) by the first end piece <NUM>, which at the same time limits the axial displacement of the second bar <NUM> in this direction. As a result, the mobile end piece <NUM> can only move in an axial direction parallel to a longitudinal axis of said second bar <NUM>. The mobile end piece <NUM> can also be rotated around the longitudinal axis of the second bar <NUM>.

The quick release system also comprises locking means formed by a locking pin <NUM> that is firmly connected to it and a push button <NUM>. The locking pin <NUM> comprises a head <NUM> and a cylindrical body <NUM>, the head <NUM> being larger than the body <NUM> and cooperating with a hole <NUM> formed in the push button. As shown on the figures, the locking pin <NUM> has a mushroom shape, the head <NUM> comprising a slope <NUM> and the body comprising a groove <NUM>.

According to the invention, the locking pin <NUM> is fixed on the body <NUM> between the second free end <NUM> of the first bar <NUM> and the second end <NUM> of the second bar <NUM>.

It is also possible to merge the locking pin <NUM> and the second free end <NUM> of the first bar <NUM> so it forms one and same element. Such an arrangement would be an easy task for a man skilled in the art and is not shown on the figures.

The push button <NUM> also has a slope <NUM> located just before the hole <NUM>, the hole <NUM> and the slope <NUM> being arranged to cooperate with the slope <NUM> of the locking pin <NUM> to ease the lock of the mobile end piece <NUM> onto the body <NUM>.

The mobile end piece <NUM> has a milling <NUM> in which the push button <NUM> is located. The push button <NUM> can move in a direction perpendicular to the plane of the end link <NUM> within this milling <NUM>. The mobile end piece <NUM> comprises at least one spring <NUM>, and preferably two springs <NUM>, cooperating with the push button <NUM> to maintain it in its locked position. The two springs <NUM> are located on each side of the push button <NUM>.

As shown on <FIG>, the mobile end piece <NUM> also comprises guiding means for the push button. The guiding means are formed by the mean of through holes <NUM> in the mobile end piece <NUM>, and into which two tenons <NUM> are inserted. Plus, the push button <NUM> has oblong holes <NUM> which, in conjunction with the two tenons <NUM>, limit the stroke of the push button <NUM> and maintain it inside the milling of the mobile end piece <NUM>.

In the locked position, the push button <NUM> is locked into the groove <NUM> of the locking pin <NUM> as can be seen in <FIG> or <FIG>, which prevents the push button <NUM> from moving in the direction of the longitudinal axis of the second bar <NUM>. Since the push button <NUM> is also limited by the milling <NUM> in the mobile end piece <NUM> in a direction perpendicular to the plane of the end link <NUM>, the movement of the mobile end piece <NUM> in this direction is consequently also prevented.

To unlock the mobile end piece <NUM>, the push button is pressed perpendicularly to the plane of the end link <NUM> to the bottom of the milling <NUM> in the mobile end piece <NUM>, the locking pin is released (<FIG>) and the mobile end piece <NUM> can be pulled in the longitudinal axis of the second bar <NUM> within its constraints (<FIG>).

When the mobile end piece is fully extended, it can be swivelled around the longitudinal axis of the second bar <NUM>. This releases first bar <NUM> and enables the strap to be exchanged (<FIG>).

Then to lock the mobile end piece <NUM>, the mobile end piece is rotated back until the first bar <NUM> is aligned with the hole <NUM> in the mobile end piece <NUM> again. After the alignment is done, the wearer pushes the mobile end piece <NUM> in the direction of the longitudinal axis of the second bar <NUM>. After a short distance, the slope <NUM> of the locking pin <NUM> comes into contact with the slope <NUM> of the push button <NUM> so the slope <NUM> of the push button <NUM> slides over the slope <NUM> of the locking pin <NUM>, causing the push button to move perpendicularly to the plane of the end link <NUM> inside the milling <NUM>.

When the edge of the push button <NUM> finally slides over the edge of the locking pin <NUM>, the push button <NUM> is pressed by the force of the springs <NUM> and thus engages in the groove <NUM> of the locking pin <NUM>. The mechanism is now in its locked position again.

The invention also relates to a wristband <NUM> comprising the quick release system according to the invention.

Claim 1:
Quick release system for an interchangeable watch strap on a clasp, the quick release system comprising:
- an end link (<NUM>) for securing the watch strap (<NUM>) on the clasp (<NUM>), the end link comprising a body (<NUM>) and two lateral end pieces (<NUM>,<NUM>) placed on each side of the body (<NUM>), characterized by first lateral end piece (<NUM>) being in one piece with the body (<NUM>) and the second lateral end piece, called mobile end piece (<NUM>), able to slide away from the body (<NUM>),
- a first bar (<NUM>) extending from the first end piece (<NUM>), and comprising a first end (<NUM>) being fixed to the first lateral end piece (<NUM>) and a second free end (<NUM>) cooperating with a bore (<NUM>) of the mobile end piece (<NUM>);
- a second bar (<NUM>) extending from the first end piece (<NUM>), comprising a first end (<NUM>) able to slide inside the first end piece (<NUM>), and a second end articulated to the mobile end piece (<NUM>);
- a retaining stem (<NUM>) arranged coaxial and fixed to the second bar (<NUM>), so that the mobile end piece (<NUM>) is moveable parallel to a longitudinal axis of said retaining stem (<NUM>), and so that the mobile end piece (<NUM>) can be moved from a locked position where the mobile end piece (<NUM>) is held against the body (<NUM>), to an unlocked position where the mobile end piece (<NUM>) is free,
- locking means to lock the mobile end piece (<NUM>) on the body (<NUM>), said locking means comprising a push button (<NUM>) sliding inside the movable end link (<NUM>), and a locking pin (<NUM>) fixed to the body (<NUM>) and cooperating with the push button (<NUM>) to allow said mobile end piece (<NUM>) to be locked to or to be unlocked from the body (<NUM>) of the end link (<NUM>).