US3686734A - Method of manufacturing jewels of gold or platinum or their alloys - Google Patents

Abstract

A method of making jewelry from precious metals, such as gold, platinum, etc., and their alloys, comprises starting with a rectangular strip of wire mesh, (known in the trade as ''''milanese''''), adding additional wire coils of progressively shorter length to opposite margins, placing the loosely woven mesh into a shaping press to progressively compress the mesh into a circular or oval shape, coating one face with molding wax, electroplating the other side with copper, annealing and scouring the first surface, hammering the surface to crush the wires into a denser mass while retaining its circular, or oval, shape, reannealing and re-scouring the mesh, coating the hammered surface with wax, repeating the copper electroplating step on the back, placing the plated surface in contact with a die having the desired design, hammering the first face again while the coppered surface contacts the die and removing the copper by acid etching.

Description

United States Patent Labarte et al.

[54] METHOD OF MANUFACTURING JEWELS OF GOLD OR PLATINUM OR THEIR ALLOYS [72] Inventors: Maurice Labarte, 31 rue Paul Cezanne, La Rochette near Melun (Seine et Marne); Jacques Lenfant, 47 rue des Petits Champs, Paris ler, both of France [22] Filed: June 29, 1970 [21] Appl. No.: 50,811

[52] [1.8. Cl ..29/160.6, 63/3 [51] Int. Cl ..B21f 43/00, 323p 13/00 [58] Field of Search ..29/l60.6; 63/3, 9, 11

[56] References Cited UNITED STATES PATENTS 1,784,786 12/1930 Durand ..29/160.6 X 2,054,408 9/ 1936 Casey ..29/160.6 X 2,200,828 5/1940 Augenstein ..59/35 2,451,780 10/1948 Siska ..63/4 2,891,306 6/1959 Fontana ..29/160.6 X

[1 1 3,686,734 5: Aug. 29, 1972 Primary Examiner-John F. Campbell Assistant Examiner-Victor A. Di Palma AttorneyChristen & Sabol [57] ABSTRACT A method of making jewelry from precious metals, such as gold, platinum, etc., and their alloys, comprises sta'rting with a rectangular strip of wire mesh, (known in the trade as milanese), adding additional wire coils of progressively shorter length to opposite margins, placing the loosely woven mesh into a shaping press to progressively compress the mesh into a circular or oval shape, coating one face with molding wax, electroplating the other side with copper, annealing and securing the first surface, hammering the surface to crush the wires into a denser mass while retaining its circular, or oval, shape, re-annealing and rescouring the mesh, coating the hammered surface with wax, repeating the copper electroplating step on the back, placing the plated surface in contact with a die having the desired design, hammering the first face again while the coppered surface contacts the die and removing the copper by acid etching.

5 Claims, 7 Drawing Figures PATENTED E 2 9 7 SHEET 1 BF 2 PATENTEBA B 1912 3.686. 734

SHEET 2 OF 2 BACKGROUND OF THE INVENTION It is known to make pieces of jewelry having the general shape of a strip or tape of the metal texture called milanese.

To obtain this texture, coils made from very thin metal wire, of a diameter ranging for example from 0.5 to 0.6 mm, and called coiled wire in the trade, are wound with interlaced turns of coils. As in textile articles, these milanese strips or tapes comprise two selvedges consisting of turns constituting the marginal coiled wires.

Up to now no attempts have been made to use the milanese texture otherwise than in the conventional strip or tape form at least, so far as the applicants are aware, no successful attempts have been made with a view to make flat elements having a circular, oval or similar surface configuration and having a certain rigidity permitting the obtaining of bracelets, necklaces, etc.

SUMMARY OF THE INVENTION This invention provides a method consisting of the following successive operations:

Firstly, a square or rectangular sheet of conventional milanese is prepared; then, on either side of this sheet, coiled wires of gradually decreasing lengths are added in order to obtain a polygonal (for example octagonal) blank; the ends of each coiled wire are soldered to the last coil of the adjacent coiled wire; the blank is placed in a shaping press comprising a plurality of convergent movable jaws of which the minimum inner total contour corresponds to that of the element to obtained the mutual convergence of these jaws is produced with a view to reduce the blank to the desired contour; one face of the texture is coated with a thin layer of molding wax and an electrolytic copper plating or deposit is formed on the other face the element is then annealed and scoured while it is held in its new shape, the non copper-plated face is hammered by using a cylindrical punch having a flat, granite-like end face, by effecting successive small passes in order to crush the texture wires and fill up all the gaps thereof so as to obtain a solid surface possibly, a finishing phase may be performed thereafter by hammering with a cylindrical punch having a flat and polished end face then the element is annealed again and scoured, and the hammered surface is coated with wax, and the non-hammered surface is copper-plated another time while holding the element in and against die formed with the counterpart of the desired pattern, the other face is hammered by means of a flat-ended cylindrical punch; the face provided with the ornamental pattern is surfaced and the copper is eventually etched off with acid.

The elements thus obtained may be assembled for example by means of flat hinge means in order to make bracelets or necklaces.

It may be noted that these jewels are characterized by well-defined advantageous features in comparison with jewels consisting of assembled rigid solid plates.

In fact, without impairing its appearance, each apparently rigid element according to this invention is characterized by a certain flexibility enabling it to assume the desired convexity.

- 2 Other features and advantages of this invention will appear as the following description proceeds with reference to the attached drawing given by way of example, not of limitation, in order to afford a clearer understanding of this invention and of the manner in which the same may be carried out in practice.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagram illustrating the central sheet as obtained after the initial step of the method of this invention;

FIG. 2 is a diagram showing a polygonal-shaped blank, in this example a octagonal blank FIG. 3 is a fragmentary view of the blank of FIG. 2

FIG. 4 is a plan view of a shaping press FIG. 5 is a perspective view showing the device comprising a plurality of movable jaws for carrying out the method of this invention FIG. 6 is a-view of a typical decorative pattern obtained on an element according to the method of this invention, and

FIG. 7 is a perspective view of a bracelet obtained by juxtaposing flat-hinged elements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in these Figures, the method constituting the subject matter of this invention may be carried out by forming firstly a rectangular sheet N1 having its four corners denoted A, B, C, and D consisting of conventional milanese texture obtained by mutually winding or interlacing coiled wires Ca-Cb of precious metal (gold, platinum or their alloys)having a diameter, say, of 0.6 milimeter, formed for example on a 0.9 mm mandrel with a 1.15 mm spacer providing a turn pitch of 1.74 mm.

To obtain this hexagonal shape A, B, E, F, D, C, H and G, there are added, on either side of the endmost coiled wires Ca and Cu constituting the sides AC and BD, other coiled wires of gradually decreasing length, the last coiled wires constituting the selvedges GH, EF.

The ends of the coiled wires constituting either sides AB and CD or GA, I-IC, BE and DF are soldered at M on the turn of the interlaced coiled wire to the external bare surface of this turn.

In order to impart a certain flexibility to the texture and permit the compression thereof as will be explained presently, a very thin saw-cut as designated by the reference letter S in FIG. 3 is formed on each turn along the sides GA, BE, DF, and HG adjacent said solders M. Preferably, this saw-cut is applied only to every other turn.

In the case of sides BE and HC, the saw-cuts are visible on one face of the texture and in the case of sides AG end DF the saw-cuts are visible on the opposite side.

The ends K of the turns are sawn off so as to be level with solders M. The face of the octagonal blank Ebl which is selected to constitute the front side is protected by a thin coat of molding wax which is caused to penetrate into the texture by using a small fly-press.

The blank is then shaped, this operation being performed by using a shaping press Pr as illustrated in FIG. 4 this press comprises a number of actuators V (here four in number) having convergent pistons provided with jaws Z. It is clear that the convergent movements of actuators V will produce a distortion of the octagonal blank Eb] so as to impart its final shape Eb2 thereto (i.e. a circle in the example contemplated herein). The contraction of the texture in the corner zones of the octagon is facilited by the saw-cuts S. Of course, blanks having shapes other than circular, such as oval, etc, may be obtained by providing beforehand a blank of suitable configuration (for example that of an irregular polygon) and by utilizing, if necessary, a shaping press comprising a different number of actuators converging towards a common center or, possibly, towards a plurality of focuses.

Of course, during this constricting or contracting operation due consideration must be had for the texture shrinkage (about 4 to 5 percent in the case of a 35 millimeter disk).

Then a three-hour copper electroplating is performed in an acid copper bath with a 2 volt rectifier voltage and a cathode current density of 2 amperes per square decimeter, in order to form a copper deposit of about 0.05 mm on the back face.

The thus copper-plated elements are annealed (to remove the wax) and scoured (pickling).

The object of this copper-plating is to form between the coiled wires a metal deposit which will act as a spacer during the following steps.

The resulting blank Eb2 is protected on the copperplated side by means of a reinforced adhesive material (cotton or glass fiber) and belted edgewise by means of a flat copper wire (of say 0.7 X 2 mm). Having thus prepared the blank, the latter is disposed in the device illustrated in FIG. 5 with the copper-plated face protected by said adhesive material disposed beneath in the bottom of the cavity R machined to the desired shape and consisting of two jaws R1, R2 which are either both movable or one fixed and the other movable in relation to the other under the control of pressure setting screws W, said jaws being mounted in a base member U formed with adequate slideways.

On the bare face of the blank the hammering operation is then carried out by using a short-stroke eccentric press (for example a press giving a stroke of 5 to 7 mm) provided with a cylindrical punch having a fiat, granite-like end face. A first step consists in crushing the texture wires step by step by moving the tool on the press table in order to fill up all the cavities and form a perfectly solid surface. A second finishing step carried out on the same press but by means of a cylindrical punch having a flat and polished end face permits of obliterating the marks left by the breaking hammering operation performed by means of said granite-like punch end.

The blank is then removed from the device, annealed, scoured and covered on its edges and on the hammered surface with a thin layer of molding wax applied in the hot state. Then a second prolonged copperplating operation is carried out on the back face of the texture in order to deposit a relatively thick copper layer (of about 0.7 to 0.8 mm), this second electroplating operation lasting about hours. This complementary copper-plating operation introduces into the interstices of the back face, between the coiled wires, a copper deposit considerably thicker than the one formed during the first operation, and this copper will also constitute a spacer material between the wires.

Then the element is re-introduced into the device shown in FIG. 5, the bottom of this device receiving beforehand a die reproducing the desired ornamental pattern, for example the one shown at De in FIG. 6. The previously hammered side is placed in front of this die. Then another hammering operation is performed after the necessary care has been taken for preventing any distortion of the blank, notably after having placed a flat copper belt around it. This last hammering operation is performed by using a cylindrical punch having a flat end face, whereby the texture will penetrate all the details of the die, the duration of this hammering step depending on the desired relief. If polished portions are desired, for obtaining a contrast with respect to the granite-like surface portions, the face provided with the ornamental pattern is surfaced and then etched in a bath of hot nitric acid, and the copper is thus removed to restore one fraction of the initial flexibility and purity of the texture. This result is due to the two successive copper-plating operations having somewhat locked the interlaced coils during the hammering operations, so that when the copper is eventually removed the gaps between adjacent wires are substantially zero on the front or right side, and relatively wide on the back or reverse side.

The elements Pa (FIG. 6) thus obtained may of course be utilized either singly (for example for making ear-clips, buttons, etc), or in combination to constitute chains suitable for making necklaces, collars, belts, etc however, a most convenient combination of these elements is in the making of bracelets (FIG. 7) for as already explained in the foregoing each element Pa, due to its specific manufacturing method, has a certain stiffness associated nevertheless to a limited flexibility in one direction, whereby each element constituting a bracelet can be curved in two directions for accommodating the wrist configuration (i.e. the cross-sectional contour and taper thereof).

Although this invention has been described and illustrated with specific reference to certain forms of embodiment thereof, it will readily occur to those skilled in the art that various modifications and variations may be brought thereto without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed as new is:

1. Method of making jewelry of gold, platinum or their alloys, which comprises the steps of preparing a rectangular sheet of conventional milanese; adding coiled wires of gradually decreasing length on either side of this sheet in order to obtain a polygonal blank, soldering the ends of each coiled wire to the last coil of the adjacent coiled wire, placing the resulting blank in a shaping press comprising a plurality of convergent movable jaws of which the minimum inner overall contour corresponds to that of the element to be obtained after operating said press, subsequently causing said jaws to converge towards one another in order to contract the blank disposed therebetween to the desired contour, coating one face of the blank with a thin layer of molding wax, electroplating a copper deposit on the other face of said blank, annealing and scouring the element thus obtained, hammering the wax-coated face of the element while held in its new shape with a cylindrical punch having a flat, granite-like end face, by using successive small passes in order to crush the wires of the blank to fill up all the gaps thereof and obtain a solid surface, finishing the element by another hammering operation using a cylindrical punch having a flat and polished end face, re-annealing and re-scouring the element, coating the hammered surface thereof with wax, re-plating the non-hammered surface with copper, and while holding the element in and against a die formed with the counterpart of the desired pattern, again hammering the other face with a flat-ended cylindrical punch, and removing the copper by etching with acid.

2. The method set forth in claim 1, which includes the steps of making thin saw-cuts in the end turns of certain of the coiled wires added to the rectangular sheet of conventional milanese.

3. The method as set forth in claim 1, which includes the steps of removing the ends of the coiled wires projecting outwardly beyond the soldering.

4. The method as set forth in claim 1, which includes the step of forcing the thin layer of molding wax to penetrate the blank by means of a small fly-press.

5. The method as set forth in claim 1, which includes the step of applying a reinforced adhesive material to the copper-plated side of the blank and applying a marginal belt of flat copper wire to the blank prior to a hammering step.

Claims (5)

1. Method of making jewelry of gold, platinum or their alloys, which comprises the steps of preparing a rectangular sheet of conventional milanese; adding coiled wires of gradually decreasing length on either side of this sheet in order to obtain a polygonal blank, soldering the ends of each coiled wire to the last coil of the adjacent coiled wire, placing the resulting blank in a shaping press comprising a plurality of convergent movable jaws of which the minimum inner overall contour corresponds to that of the element to be obtained after operating said press, subsequently causing said jaws to converge towards one another in order to contract the blank disposed therebetween to the desired contour, coating one face of the blank with a thin layer of molding wax, electroplating a copper deposit on the other face of said blank, annealing and scouring the element thus obtained, hammering the wax-coated face of the element while held in its new shape with a cylindrical punch having a flat, granitelike end face, by using successive small passes in order to crush the wires of the blank to fill up all the gaps thereof and obtain a solid surface, finishing the element by another hammering operation using a cylindrical punch having a flat and polished end face, re-annealing and re-scouring the element, coating the hammered surface thereof with wax, re-plating the non-hammered surface with copper, and while holding the element in and against a die formed with the counterpart of the desired pattern, again hammering the other face with a flat-ended cylindrical punch, and removing the copper by etching with acid.

2. The method set forth in claim 1, which includes the steps of making thin saw-cuts in the end turns of certain of the coiled wires added to the rectangular sheet of conventional milanese.

3. The method as set forth in claim 1, which includes the steps of removing the ends of the coiled wires projecting outwardly beyond the soldering.

4. The method as set forth in claim 1, which includes the step of forcing the thin layer of molding wax to penetrate the blank by means of a small fly-press.

5. The method as set forth in claim 1, which includes the step of applying a reinforced adhesive material to the copper-plated side of the blank and applying a marginal belt of flat copper wire to the blank prior to a hammering step.

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