EP0015242B1 - Piece of jewelry protected by a hard-metal screen - Google Patents

Description

US-A-3,242,664 describes a piece of jewelry protected by a hard metal shield, each part of the external surface of which, when worn, is particularly exposed to contact with foreign bodies, is constituted by a protective part. thin, made of sintered hard metal, which covers a corresponding part of a body of machinable material and which is fixed to this body. In the case of this previous proposal, the fixing of the protective parts was provided by welding.

This method of fixation, however, presents difficulties. By welding, for example, a sintered hard metal plate on a steel body, this plate is exposed to high tensions, due to the difference between the coefficients of thermal expansion. In addition, given the welding temperatures, located around 1000 ° C, it is not possible to give the hard metal part its final appearance before welding. This piece must be finished last. However, as the operations of termination, including polishing, are, in the manufacture of the piece of jewelry, the most laborious and the most delicate, therefore also those giving rise to the greatest number of pieces of scrap, they often cause delays Delivery. Finally, when the polishing of the hard metal part must be followed by a coloring of this part, it is also a question of masking the parts of the piece of jewelry which must not be colored, then of rediscover them after the treatment, which further complicates termination, while prolonging its development and increasing the risk of waste.

In practical versions, it has been to massive protective parts rather than thin plates that has been used so far for the shielding of jewelry pieces. In addition, in order to be able to completely finish the body of machinable material and the sintered hard metal shielding each for itself, we have thought of gluing them together.

Unfortunately, adhesives do not offer any guarantee. In some climates, they fall apart.

To achieve the fixing in question, mechanical locks were also used, even using "locks" made of rubber material (see US-A-3,643,423).

This method of attachment, however, requires quite precise particular shapes of the body of machinable material and of the protective part, which complicates the manufacture, in particular of the hard metal part, due to the relatively large shrinkage during sintering and the fact that it should be formed entirely before sintering, if we want to avoid laborious subsequent machining.

Even before the use of sintered hard metals in jewelry pieces, parts were already known comprising a body of easily machinable material, protected by a shield of harder material (see in particular the patents CH-A-181,293 and CH-A -236.616). In these cases, the shielding is however only carried out by a sheet of material which is still malleable, such as stainless steel, which can therefore be formed at will without difficulty, by folding or drawing, in order to cover the softer body with the part to be protected and to be fixed to the latter simply, by wrapping or in any other purely mechanical way (riveting, crimping).

The means used to attach such a shield to the body to be protected are however not applicable to a sintered hard metal shield.

To fix a plate on the body of a piece of jewelry, mechanical hooking is also known without intermediate "lock" (see patent FR-A-2 264 501). To block the dovetail tenon in the corresponding slide, this known attachment requires however an elastic deformation of the plate, which cannot be envisaged in the case of a sintered hard metal plate.

US-A-3,837,163 describes a piece of jewelry or watch strap made entirely of hard metal. However, this solution is not satisfactory like the previous ones due to the fact that under these conditions there is not any freedom to choose the shape of the part and what is more the hard metal is then in contact with the skin.

We also know that in the manufacture of tools, the attachment of a sintered hard metal plate to a body, for example made of steel, is commonly performed. This fixing is ensured by welding one of the faces of the hard metal plate on the body. However, if the wafer is relatively extended, at least in one dimension, this welding is not carried out directly on the steel. As already indicated above, the difference between the coefficients of thermal expansion of steel and hard metal gives rise in the hard metal plate, during cooling after welding, which takes place at a temperature of about 1000 ° C, internal tensions which expose it to the risk of rupture. This is why the attachment of the hard metal plate of the tools is carried out by interposing, between steel and hard metal, a plate of very malleable material, for example copper.

For aesthetic reasons, also and above all of corrosion, it is however not possible to use this method of attachment in pieces of jewelry. In addition, when the piece of jewelry is a wristwatch box, the part most exposed to insults is the area surrounding the glass, it may be advantageous to give the hard metal protective part the role of bezel, to fix the glass to it, or even to use it as a closing member of the box, therefore to make it removable and not permanent, its fixing to the body of the box is made of machinable material.

Taking into account all of the foregoing considerations, the invention aims to provide a piece of jewelry and in particular timepieces of the type defined at the beginning of this specification and which is devoid of all the drawbacks attached to the previous solutions. In particular, the object of the invention is to fix the hard metal part other than by direct welding to the body of the piece of jewelry, which therefore avoids all the difficulties caused by the differences in thermal behavior of the materials from which the component elements are made. the piece of jewelry.

Thus, according to a common inventive concept which can be implemented in different ways, the invention provides for replacing the means of fixing of the prior art materialized by a direct welding of the protective element on the body of the piece of jewelry, by fixing means which can be described as "mechanical" which surprisingly makes it possible to solve the problems posed in this kind of assembly which, since the proposal made in patent US-A-3,242,664 focused on direct welding, had not found a satisfactory solution. In this regard, it should be noted that, given the difficulties caused by the dispersion of the thermal expansion coefficients of the materials to be assembled, the welding technique recommended in this prior document has not found practical application, as is known the Applicant all the better since she is herself the holder of this patent.

According to a first embodiment, the invention therefore relates to a piece of jewelry protected by a hard metal shield, each part of the external surface of which, when worn, is particularly exposed to contact with foreign bodies , is constituted by a thin protective part, made of sintered hard metal, which covers a corresponding part of a body of machinable material and which is fixed to this body, characterized in that the fixing of the protective part is carried out so punctual, by at least one stud welded against the face of the protective part intended to be turned towards said body, this stud being retained in a hole in the body of machinable material at a point of said exposed part covered by the protective piece.

According to a second embodiment, the invention also relates to a piece of jewelry protected by a hard metal shield, each part of the external surface of which, when worn, is particularly exposed to contact with foreign bodies, consists of a thin protective part, made of sintered hard metal, which covers a corresponding part of a body of machinable material and which is fixed to this body, characterized in that the fixing of the protective part is carried out punctually , by at least one fixing stud in the form of a stud composed of a rod which passes through a bore in the protective part and is retained in a bore of said body and of a decorative head, integral with this rod, which holds the protective part pressed against the body of machinable material.

Thus, the shape which it is desired to give to the piece of jewelry is obtained following traditional operations, carried out on the workable material of the body of the piece of jewelry. The hard metal protective parts, which have an approximately constant thickness and which are then fixed to this body, no longer modify their shape; they just increase the volume somewhat. The body of machinable material and the hard metal shield can be made entirely for each other and fixed to each other at the last moment, just before delivery. As the fixing studs of the protective part cover only a very small part of the face of the latter, it is not difficult to find a suitable location for them.

In addition, in the first embodiment, they have the advantage of being able to be welded without risk against the face of the protective part intended to be pressed against the body of machinable material.

Since this welding is only punctual and therefore affects only a very small part of the hard metal protective part, the risk of rupture due to the internal tensions generated as a result of welding is completely eliminated. Furthermore, the stud or studs welded to the hard metal part, during its manufacture, in no way hamper the termination operations of this part, since they are located on a completely hidden face of the latter.

According to the second mode of implementation, the head of the studs, judiciously polished, can create the illusion of a precious stone set on the protective piece of hard metal.

As for the fixing of the studs to the body of the piece of jewelry, it can be achieved in many ways. It can be removable or permanent, mechanical or other (welding, bonding). In cases where the protective part has no reason to be removable, each of the studs can be retained permanently in a hole passing through the body by a rivet at its end.

In this regard, it should be noted that it is widely known to ensure the joining of parts by riveting. This is shown, for example, in the book "General technology and construction" Duroux and Faucard - Editions André Desvignes, 1969, pages 184 to 194. On page 185, the authors state under a) 3 °: "To avoid corrosion phenomena, rivets and rivets must be of the same metal ". As a result, according to the generally accepted conception, the idea of associating a piece of hard metal on one body in another metal by riveting would be immediately discarded by those skilled in the art. Furthermore, in the first paragraph on page 184 of the cited work, it is also stated that the function of the rivets is to make a connection between thin pieces. However, if the hard metal part used in the invention is generally thin, it is not the same for the body which is intended to receive it (watch case for example). This would be another reason for those skilled in the art to discard the rivets in the kind of assemblies discussed above. However, according to the above characteristic, and contrary to accepted ideas, the invention proposes to use the rivet which has been found to give complete satisfaction.

However, in certain cases, the removability of the protective part is essential. In these cases, the fixing of the studs to the body of machinable material can be advantageously carried out by retaining them in the corresponding hole of the body of machinable material by a screwed fixing member engaged in this body transversely to the hole so as to open therein to clamp the stud in place. Such a blockage is as simple as it is effective. The fixing members thus defined have, in fact, the advantage of being entirely camouflaged while nevertheless being easily accessible.

While it has not been possible until now to set precious or semi-precious stones in sintered hard metal, the invention makes it possible precisely to associate with a hard metal part such ornamental elements, the piece of hard metal then being arranged to receive the ornamental element.

The pieces of jewelry which it is advisable to protect by means of a sintered hard metal shield are mainly watch cases, more particularly wristwatches, metal bracelets, cuff links, brooches, pendants.

In the case of wristwatch boxes, it is essentially the upper face of the bezel which is exposed to contact with foreign bodies. On it practically depends the appearance of the watch. So just shield this side. When the box includes a bezel which completely surrounds the glass, the protective part can itself be this bezel by compressing a seal between it and the body of the box. It then has the advantage of being able to constitute the closing member of the box and therefore to avoid any joint on the bottom side, by giving the body of machinable material of the box the shape of a case back.

In the case where the piece of jewelry is a metal bracelet with elements articulated to each other, it is advantageous to use fixing studs formed by the ends bent at right angles to a thin elongated piece, the part of this piece extending between the ends being deformable in the longitudinal direction and being welded against a part of the protective part.

Although the weld here affects a much larger part of the face of the protective part than in the previous cases, the difference between the coefficients of thermal expansion of the protective part and of the part carrying the fixing studs is not likely generate dangerous tensions given the deformability of the latter.

• La Fig. 1 est une vue en plan de la première forme d'exécution, dont certaines parties sont arrachées.
• La Fig. 2 est une coupe selon la ligne II-II de la Fig. 1.
• La Fig. 3 est une vue en plan d'une partie de la seconde forme d'exécution.
• La Fig. 4 est une coupe partielle, analogue à celle de la Fig. 2, de cette seconde forme d'exécution.
• La Fig. 5 est une vue en plan à échelle réduite de la troisième forme d'exécution.
• La Fig. 6 est une vue en plan semblable à celle de la Fig. 5, représentant la quatrième forme d'exécution.
• Les Fig. 7 et 8 sont des coupes analogues à celle de la Fig. 2, représentant respectivement les cinquième et sixième forme d'exécution.
• La Fig. 9 est une coupe d'un élément de la septième forme d'exécution.
• La Fig. 10 est une vue en perspective explosée d'une partie de la huitième forme d'exécution, et
• la Fig. 11 est une coupe d'un élément de cette huitième forme d'exécution.

Eight embodiments of the piece of jewelry according to the invention are shown, by way of example, in the accompanying drawings.

• Fig. 1 is a plan view of the first embodiment, some parts of which are cut away.
• Fig. 2 is a section along line II-II of FIG. 1.
• Fig. 3 is a plan view of part of the second embodiment.
• Fig. 4 is a partial section, similar to that of FIG. 2, of this second embodiment.
• Fig. 5 is a plan view on a reduced scale of the third embodiment.
• Fig. 6 is a plan view similar to that of FIG. 5, representing the fourth embodiment.
• Figs. 7 and 8 are sections similar to that of FIG. 2, respectively representing the fifth and sixth embodiment.
• Fig. 9 is a section through an element of the seventh embodiment.
• Fig. 10 is an exploded perspective view of part of the eighth embodiment, and
• Fig. 11 is a section through an element of this eighth embodiment.

The first embodiment of the piece of jewelry according to the invention (Fig. 1 and 2) consists of a wristwatch case. This box includes a case back 1 and a bezel case 2, both made of steel. The movement 3 of the watch is fitted from the top into a housing 4 of circular shape of the case back 1. It is held in place in this housing by a projection 5 of the case back 1, on which the thread 6 of the plate of the movement 3. The dial 7 extends beyond the movement 3. It extends into a second housing 8, also of circular shape, of the case-back 1. The case-bezel 2 is fitted around a cylindrical seat 9 of the case-back -carrure 1. It carries the horns 10 for fixing the bracelet. She rests on a flange 11 of the backband 1 and is held in place by four screws 12.

The case described is closed in a leaktight manner by a flat sapphire crystal 13. The edges 14 of the glass are bevelled. The glass 13, rectangular, is held in place in a slide 15 formed in projections 16 of the middle part-bezel 2, located above the horns 10 and extending between them. The other two sides of the box are covered by the glass 13, which, at these locations, extends to the edge of the box.

The tightness of the closure of the case is ensured by an annular lining 17 that the glass 13 compresses at the bottom of a groove formed by the internal cylindrical wall 18 of the middle part-bezel 2, the upper face 19 of the base part 1 and a flange 20. The compressed gasket 17 also has the effect of preventing an inadvertent sliding of the glass 13 in the slide 15. For this reason, the glass 13 must be put in place in the slide 15 before tightening the screws 12, when closing the box.

It emerges from the preceding description and from the drawing that the only parts of the box liable to be damaged in contact with foreign bodies, are the upper faces 21 of the projections 16, which act as glasses. To preserve the appearance of the box, it suffices to protect these faces 21.

In the first embodiment, this protection is provided by a shield of sintered hard metal, consisting of two plates 22, resting on the faces 21. As the latter are flat, the plates 22 are flat. Their outline is trapezoidal and the two long sides are bevelled. Given the very simple shape of the plates 22, their manufacture does not encounter any difficulty. Their constant thickness is chosen so that these plates 22 are able to withstand alone the pressures or shocks of foreign bodies which they may accidentally undergo during use.

The shielding described, which is extremely rational because it is limited to the essential, could not, however, have been achieved with any guarantee without the solution described below to secure the hard metal plates 22 to the steel body, here constituted by the middle-bezel 2.

To keep plated on the faces 21 the hard metal protective parts, constituted by the plates 22, two studs 23 are welded against the underside of the plates 22, not affected by the termination operations, since it is hidden. The welding of the pads 23 is carried out after the sintering of the pads 22, but before subjecting the latter to the termination operations. The studs 23 are made of steel and they can be formed by bar turning. Although the contact surface between these pads and the pads 22 is reduced, the soldering provides ample fixing of the pads 23.

After welding the studs 23, the visible faces of the plates 22 are polished as in the case of known parts. They can also be coated with a colored layer. In the case of platelets in tungsten carbide, this coloring can, for example, be carried out by forming a layer of nitride on the surface of the wafers.

Below the face 21 and between the horns 10, the middle-bezel 2 has recesses 24 and holes 25, drilled in the face 21 and opening into these recesses. A recess 26, of larger diameter, is formed at the entrance of the holes 25 to receive the enlarged head 27 of the studs 23. In order to avoid any permanent tension in the plates 22, the depth of the recess 26 can be chosen very slightly less than the height of the head 27. In this way, it is the head 27 which will be pressed against the bottom of the recess 26 and not the plate 22 against the face 21, when the studs 23 are fully engaged in the holes 25.

When the plates 22 are in place, the ends of the studs 23 protrude into the recesses 24 of the middle part-bezel 2, which enables the studs 23 to be riveted and thus fix the plates 22 permanently to the middle part-bezel 2. This shore obviously does not subject the middle-bezel 2 and the plates 22 to any stress which would risk damaging these parts in any way. It can therefore be carried out lastly, which allows the middle part of the bezel 2 and the plates 22 to be completed each for itself. It is therefore not necessary to wait until the plates have been able to be fixed to the steel body of the box before undertaking the termination, risking then losing the whole box if, during polishing, one or the another of the plates proves to be unusable.

The drawing shows that the shape of the box is determined by the two parts 1, 2. The plates 22 simply have the effect of raising the parts of the box taking the place of glasses. As parts 1 and 2 are made of steel, their machining presents no difficulty. It goes without saying that these two parts 1, 2 could also be made of any other machinable material, brass, aluminum and even synthetic material.

To hide the lining 17 and the flange 20, a metallization layer 28 is deposited on the periphery of the glass 13, on its underside.

The second embodiment (Fig. 3 and 4) differs from the first only by the presence of stones 29, precious or semi-precious, housed in openings 30 of the plates 31 of hard metal. The walls of the openings 30 are slightly inclined so that the stones 29 are held in place by pinching between the edge of the openings 30 and the face 21 of the projection 16.

The piece of jewelry according to the third embodiment (Fig. 5) also consists of a wristwatch box. This includes a bezel which completely surrounds the glass 32. In this case, the hard metal protective part is constituted by a thin frame 33, which completely covers the bezel of the box. The fixing of this frame to the body of the box, made of easily machinable material, is ensured by four studs 34, welded against its underside.

The fourth embodiment (Fig. 6) differs essentially from the third only by the fact that the shielding is not constituted by a hard metal protection piece in one piece, but by a set of square plates 35, juxtaposed and fixed to the body of the box, made of easily machinable material, each by a pad 36. Although the pads 36 are cylindrical, like those of the previous embodiments, the pads 35 are not likely to rotate around their pad 36. Their juxtaposition keeps them in place.

If, in other embodiments, such a displacement was to be feared, by using only one stud to ensure the attachment of a protective piece of hard metal, it would suffice, to avoid this risk, to '' use a prismatic stud and engage it in a correspondingly shaped hole in the body of machinable material in the piece of jewelry.

The fifth embodiment (Fig. 7) also consists of a wristwatch case. This includes a steel back 37, which came from manufacturing with horns 38 for fixing a bracelet and a thin veil 39 joining the horns 38 located on the same side to each other. of the box. The backband 37 has various housings 40, 41, 42, 43, respectively for the movement 44 of the watch, for a thread 45 of the movement ensuring its axial position in the case, for the dial 46 and a flange 47, and for a seal 48 of circular profile, surrounding the flange and thus being trapped in a peripheral groove of the box.

The movement 44 and the dial 46 are enclosed in their respective housings by a bezel 49 made of hard metal, carrying a flat glass 50, made of tempered mineral or sapphire. The bezel 49 is also flat and barely a little thicker than the glass 50, so that a housing 51, acting as a notch of ice, can be arranged there. Thus, the glass 50 can be embedded inside the bezel 49, so that its upper edge is protected from scratches. According to the usual practice in the case of hard glasses, a sleeve 52, made of a softer material than the glass and the bezel, is interposed between these two parts. This sleeve forms a cushion compensating for the manufacturing tolerances of the glass and of the housing 51 as well as the difference between the coefficients of thermal expansion of these two parts; it also seals the joint between them.

To close the box described, the bezel 49 is pressed against the flat upper face 53 of the case back 37, compressing the lining 48 in the groove formed by the housing 43 and the flange 47. It is retained in this position by the heads 54 of four studs each having a rod 55 engaged in a bore 56 of the backband 37 and passing through holes 57 of the bezel 49. Locking screws 58, located between the horns 38, under the sails 39, retain the studs 54, 55 axially in place, removably.

As these studs 54, 55 are normally stressed only in the traction exerted on them by the lining 48 and incidentally in shearing due to possible transverse shocks, their rod 55 can have a relatively small diameter, less than a millimeter, especially if it is made of steel. Their head 54, which it suffices to make with a diameter just a little larger than that of the rod 55, therefore only constitutes a very small protuberance on the bezel. By giving a judicious shape to its polished upper face, it is possible to create the illusion of stones set in the bezel 49. By providing a conical entry to the holes 57, it would even be possible to drown the head of the studs in the bezel.

As the planar telescope 49 has an at least approximately constant thickness, its manufacture is relatively simple, whatever contour this telescope has. The risk of malformations due to shrinkage during sintering is also reduced. Since this bezel simply increases the thickness of the box and does not significantly modify the plastic, the latter is essentially determined by the case back 37, which constitutes the body of the box and which can be machined so usual.

Because it is pressed against the body 37, the bezel described also has a thickness sufficient to withstand not only the deformations, but especially the shocks under the effect of the stresses to which the box normally risks being subjected to use. . As it is mainly the upper side of the cases which is exposed to accidental contact with foreign bodies, when the watch is normally worn on the wrist, and it is above all this side which is then visible, the hard metal bezel 49, completely covering the upper face of the body 37 constitutes an adequate protective shield thereof, guaranteeing the durability of its initial appearance. As for the two diametrically opposite sails 39, each of which connects the two horns 38 located on the same side of the box, they no longer form part of the actual enclosure of the movement; rather, they are integrated into the bracelet, in particular if it is made of steel.

The sixth embodiment (Fig. 8) differs from the fifth only in the shape of the upper face of the box. Instead of having a flat upper face, the case back 37a has an inclined upper face 53a. The bezel 49a has on its side an inner section 59 with flat faces, carrying the glass 50 embedded in the notch of ice 51 and an outer section 60 with inclined faces. The holes 57a, passing through this outer part 60 of the bezel 49a, are perpendicular to its faces, just as the holes 56a in the body 37a are perpendicular to its upper face 53a, so that the rods 55 of the studs are engaged obliquely in the box. The locking screws 58 of the studs remain perpendicular to their rods 55.

In this case also, the telescope has an approximately constant thickness and, in the closed position, it is pressed against the body 37a with which it completely covers the upper face, leaving only the webs 39a joining the horns 38a, on each side of the box. The role of this telescope 49a is therefore exactly the same as that of the bezel 49 of the fifth embodiment.

The piece of jewelry according to the seventh embodiment (Fig. 9) consists of a metal bracelet, composed of a series of elements hinged to each other. Fig. 9 is a cross section of one of these elements. This includes a body 61 made of stainless steel, but which could also be made of any other machinable material. Hinges 62, to ensure the articulation of the element shown with the neighboring elements of the bracelet, are integral with the body 61. They could also have come from manufacturing in one piece with it.

When worn, it is the upper face 63 of this element which is exposed to the risk of accidentally coming into contact with foreign bodies. As it is practically the only visible face of the element represented, it suffices to protect this face with a hard metal shield. Since this face is flat, its protection can be ensured by a rectangular plate 64 made of hard metal. The fixing of this plate 64 to the body 61 is ensured by a pair of studs 65 welded against its lower face and riveted to the body 61, as has been described in detail with regard to the plates 22 of the first embodiment.

The last embodiment shown in the drawing (Fig. 10 and 11) differs essentially from the previous one only by the means ensuring the attachment of the protective plates 64 to the bodies 66 of the elements of the bracelet. In that case, the two studs 67 for fixing a wafer 64 have come from manufacture with an elongated rectangular piece 68, of steel, welded against the underside of the wafer 64. Transverse slots 69, extending alternately from one and on the other side of the part 68, make this part easily deformable in the longitudinal direction, so that it will not cause dangerous internal stresses in the wafer 64, during cooling after welding. The fixing pads 67 are formed at the ends of the part 68, which, for this purpose, are folded at right angles. They are therefore flat and made elastic each by a longitudinal slot 70, formed from their end. The two branches formed by this slot 70 are brought closer to each other when the corresponding stud is introduced into its hole 71 of the body 66 of the bracelet element. The fixing of the studs 67 to the body 66 is therefore ensured by elastic clamping, it is removable. So that the hard metal plates 64 rest on the upper face 72 of the body 66 of the elements of the bracelet, recesses 73 are formed in these upper faces 72 to serve as accommodation for the parts 68.

Instead of being flat or composed of flat faces, as in the eight embodiments described, the protective parts could also be curved, the main thing being their thickness, at least approximately constant and relatively small, which gives them a form which can be described as two-dimensional, as opposed to the three-dimensional forms of practice so far.

Claims (9)

1. Piece of jewellery protected by a hard metal shielding, each external surface part of which is particularly exposed to contact with external objects during the wearing and comprises a thin protecting piece (22; 31; 33; 35; 64) of sintered hard metal which covers a corresponding part of a body member (2; 61; 66) made out of a material suitable for machining and which is secured to the body member, characterized in that the anchoring of the protecting piece (22; 31; 33; 35; 64) is achieved in a punctual way by at least a plug (23; 34; 36; 65; 67) welded against the side of a protecting piece facing said body member (2; 61; 66), this plug being retained in a hole provided in the body member made out of a material suitable for machining at a place of said exposed part covered by the protecting piece.
2. Piece of jewellery protected by a hard metal shielding, each external surface part of which is particularly exposed to contact with external objects during the wearing and comprises a thin protecting piece (49; 49a) of sintered hard metal which covers a corresponding part of a body member (37; 37a) made out of a material suitable for machining and which is secured to the body member, characterized in that the anchoring of the protecting piece (49; 49a) is achieved in a punctual way, by at least a securing plug having a pin shape (54, 55) comprising a shaft (55) extending through a boring (57, 57a) of the protecting piece (49; 49a) and retained in a hole (56; 56a) of said body member (37; 37a) and a ornamental head (54) made integral with said shaft which maintains the protecting piece against the body member (37; 37a) made out of a material suitable for machining.
3. Piece of jewellery according to any one of claims 1 and 2, characterized in that each of said plugs (23, 65) is permanently fixed in a boring (25) extending through said body member (2, 61) by riveting of its end.
4. Piece of jewellery according to any one of claims 1 and 2, characterized in that each of said plugs (54, 55; 67) is removably held in the boring of said body member (37; 37a; 66) made out of a material suitable for machining.
5. Piece of jewellery according to claim 4, characterized in that each of said plugs (54, 55; 67) is held in the corresponding boring of said machinable body member (37; 37a; 66) by a screwed securing member, engaged in this body member transversaly to the boring so as to emerge in the latter to tighten the plug.
6. Piece of jewellery according to claims 1 to 4, characterized in that the securing plugs (67) are formed by the end portions bent at right angle of a thin elongated piece (68) and in that the part of said piece extending said end portions is stretchable in longitudinal direction and is welded against a part of the protecting piece (64).
7. Piece of jewellery according to any one of the preceding claims 1 and 3 to 6, characterized in that the protecting piece (31) has at least one opening (30) forming a recess for an ornamental element (29), this element being held against said body member (2) by the edge of said opening.
8. Watertight wrist-watchcase formed by a piece of jewellery according to any one of the preceding claims, characterized in that said protecting piece (49; 49a) is the bezel of this case, the bezel carrying the glass (50) and pressing a watertight gasket (48) between said bezel and said body member (37; 37a) made out of a material suitable for machining against the top side (53, 53a) of which said gasket is pressed.
9. Band comprising hinged elements, characterized in that each of the hinged elements is formed of a piece according to any one of claims 1 to 7.

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