Abstract:
A device for fixing a bracelet on a watch case includes on at least one side of the watch case two blind perforations opening on the watch case peripheral wall and a globally U-shaped loop. The ends of the side branches of the U-shaped loop are designed to be engaged and fixed in an operative position in the blind perforations of the watch case.

Description:
BACKGROUND OF THE INVENTION 
     Most wristwatches have watch casings provided with lugs for the securement of a watch strap with the help of resilient bars or not. The need to provide lugs on the watch casing is a constraint on the shape of the watch casing, which is often considered unacceptable by designers. 
     Different devices for securing the watch strap have been proposed in which all the device is integrated into the watch casing. Such devices are complicated and cumbersome because they require often complicated machining of the watch case. 
     SUMMARY OF THE INVENTION 
     The present invention has for its object the provision of a device for securement of a watch strap on a watch casing, which overcomes the above drawbacks and which moreover will be simple, not cumbersome and particularly sturdy to be adapted for sport or dive watches. Another object of the present invention is to facilitate the mounting of a watch strap on a watch casing, whether this watch strap is flexible or rigid. 
     The accompanying drawings show schematically and by way of example two embodiments of the device for securing a watch strap on a watch casing according to the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a bottom plan view of a watch casing provided with the device according to the invention. 
     FIG. 2 is a fragmentary cross-section, on an enlarged scale, on the line A—A of FIG.  1 . 
     FIG. 3 shows in plan a first embodiment of wire loop forming part of the device. 
     FIG. 4 shows in plan a second embodiment of a wire loop forming,a part of the device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The illustrated watch casing of the watch strap securement device according to the invention comprises a casing  1 , a bezel  2  in which is fixed a crystal  3  and a bottom  4  also comprising a crystal  5 . Of course, the casing  1  could comprise an all-metal bottom in other embodiments. 
     The device for securing the watch strap on this watch casing comprises on the two sides of the casing  1 , here at  12 H and at  6 H, two blind holes  6 ,  7  provided in the watch casing and opening on the peripheral surface. These holes  6 ,  7  are parallel to each other and located in planes parallel to the plane of symmetry of the watch casing  12 H- 6 H located at an equal distance from this plane of symmetry. 
     In the illustrated example, the axis of the blind holes  6 ,  7  is inclined relative to the upper and lower surfaces of the casing  1 , the angle of inclination of these holes can vary as desired between about +60° and −60°. 
     The watch casing is also provided with screwthreaded holes  8 ,  9  opening on the lower surface of the casing  1  and whose axes intersect the blind holes  6 ,  7 . 
     In a first embodiment, the securement device of a watch strap on a watch case also comprises securement members for the watch strap constituted by generally U-shaped bent wires or rods  10 . These members or loops  10  each comprise an intermediate portion  11  adapted to receive the watch strap (not shown) and two ends  12  bent at about 90°. Each of these ends or branches  12  comprises on its lower surface, adjacent its end, a recess  13 . Between this recess  13  and the end of the leg  12 , the latter comprises a throat  15  receiving O-ring joint to guarantee stability of the assembly against vibrations. 
     The intermediate portion  11  of these loops  10  receives the watch strap, the latter can be bent about this intermediate portion or can comprise at its end a passage receiving this intermediate portion  11 . 
     Once the watch strap is threaded or fixed on this intermediate portion of the loop  10 , the ends of the legs  12  of the latter are each slipped into one of the blind holes  6 ,  7  to a position in which the recess  13  is located in prolongation of the tapped holes  8 ,  9 . 
     To complete the assembly, screws  14  are screwed into the tapped holes  8 ,  9  of the casing  1 , and their ends enter into the recesses  13  and the legs  12  of the attachment members  10  and fix the latter firmly in place on the casing  1 . The screws  14  are provided with O-ring joints  14   a,  to avoid their unscrewing under the influence of vibrations. 
     This securement device is very simple and very sturdy. Moreover, it requires only simple machining of the casing and can be incorporated into any kind of watch casing, no matter what its shape. 
     In the different modifications illustrated, the loop  10  comprises at the end of its legs  12  circular grooves  15  adapted to receive an anti-vibration joint  16 . 
     In the second embodiment shown in FIG. 4, the securement member of the watch strap or loop  10  is constituted by two elbowed rods or wires  17 ,  18  of L shape. The short legs  19  of these rods  17 ,  18  comprise as in the first embodiment a recess  13  and a groove  15 . A tube  21  permits interconnecting the free ends of the long legs  20  of these rods  17 ,  18  to create a complete securement member for the watch strap. Thanks to this embodiment in two parts of the loop  10 , first one part  17  can be fixed on the watch casing, then the portion of the watch strap comprising a passage can be slipped over the leg  20  provided with the tube  21  fixed to the casing. Then the leg  20  of the other portion  18  is slipped into the passage of the watch strap adapted to receive it. This portion  18  is introduced in such a way that the end of the leg  20  will be inserted into the free end of the tube  21 , then the free end of the leg  19  is fixed to the watch casing. 
     The tube  21  has a constriction in the middle of its length to ensure that it surrounds completely the ends of the two legs  20  in the service position and that it cannot slide too deeply on one of the legs  20 . 
     Each loop  10  can be formed from a wire or rod of stainless steel bent and machined to a diameter of 1 to 2 mm for example. It will be seen accordingly that the attachment of the watch strap to the watch is very secure. The mechanical securement is simple and sturdy. It is moreover easily disassembleable.