IL102564A - Fine jewelry rope chain and method of manufacture - Google Patents

Description

n*m>>!? ηυ>¾η DJ *TV ^in m¾n\y JEWELRY ROPE CHAIN AND METHOD OF MANUFACTURE FIELD OF THE INVENTION The present invention relates to the manufacture of fine jewelry diamond cut rope chains. Specifically the invention is concerned with hollow diamond cut faceted rope chains and to a method of manufacturing them.

BACKGROUND OF THE INVENTION Fine jewlery rope chains for necklaces and bracelets etc. have been known for a long time. The traditional rope chain, constructed from intertwined links soldered to one another has not changed basically over the past hundreds of years. Although rope chains are also manufactured by automatic machines, they are still being manufactured to a great extent by hand. In my earlier patents US 4,934,135 and 4,996,835, I disclosed and claimed rope chains and methods for preparing such rope chains having reduced weight and labour costs compared with conventional rope chains of the same chain diameter.

A particularly popular type of rope chain is commonly known as a diamond cut rope chain. Such a chain comprises flat facets on the outer perimeter of some of the chain links to provide a mirror finish surface which is very light reflective, making the chain sparkle. This diamond cut facet can easily be prepared on solid rope chains, i.e. chains made with solid links, by cutting or shaving a facet from the arced section of the link, as is well known in the art. In the case of hollow rope chains however, i.e. chains having hollow links, it is difficult to make diamond cut facets, since the outer plate of the hollow wire making up the chain link is very thin and can be as little as 0.005 mm thick, and any facet cut in the outer arced perimeter of the link would make a hole through this outer plate. A recent patent to Strobel, US 5,125,225, proposes a method for manufacturing diamond cut hollow rope chains by wrapping the rope chain about a lathe drum, freezing the drum and applying water to the chain, so as to freeze the chain in place, immobilising it, and advancing a blunt burnishing tool against the links of the chain by applying a plurality of incremental deformative thrusts of blunt force against some of the curved outer wall portions of the hollow links until this outer wall is deformed and pushed back towards the inner wall of the links, thus flattening portions of the outer walls. By rotating the lathe drum and advancing the blunt burnishing tool, additional links along the chain length receive flattened surfaces. By this method, not all of the chain links have the same flattened area. The amount of flattened area of any link will depend on the particular position of the link in the chain when the blunt burnishing tool strikes it. Those links whose outer edge is closer to the blunt tool will have a larger flat area pressed in, whereas those links of the chain that are further away from the blunt tool receive smaller increments of force and will therefore have smaller flattened areas. These flattened portions of the outer walls are then diamond cut to remove or shave off a very thin layer of metal to provide smooth and shiny facets without making any hole in the link. According to this patent, each hollow link undergoing the flattening process has one facet positioned approximately opposite the link gap, as illustrated in Figure 5 of said patent, similar to conventional diamond cut solid rope chains. Furthermore, the diamond cut rope chain according to the above patent retains the same overall chain diameter after undergoing the link deformation as before undergoing the process, although the diameter cross-section of the chain will be rectangular or hexagonal rather than round, depending on the number of facets formed therein.

SUMMARY OF THE INVENTION It is the object of the present invention to provide a faceted jewelry double helix rope chain made from tightly interfitting links of wire, each link having a small gap formed therein, characterised in that each link of the chain comprises two oppositely disposed facets of substantially equal size on the outer perimeter of said link, said facets being proximately normal to said gap, said rope chain having a substantially round diameter and furthermore having said two oppositely disposed substantially equal size facets of each link positioned on the crests of the double helix of the chain.

In a preferred embodiment of the invention, the rope chain is a hollow rope chain. The faceted rope chain of this invention will preferably undergo diamond cutting to provide a diamond cut hollow rope chain with sparkling mirror finish facets.

A faceted double helix rope chain according to this invention can be prepared by placing a double helix rope chain axially on a smooth surface, positioning a pressure plate parallel to said surface and on top of said rope chain and lowering said pressure plate under pressure in a controlled manner while applying horizontal motion to said pressure plate in a direction normal to the chain axis, thereby rolling the rope chain under pressure axially between the smooth surface and the pressure plate, flattening the outer link sections of all the cresting chain links of the double helix rope chain as it rotates and is compressed between the smooth surface and pressure plate. Thus, facets will be flattened simultaneously on all the chain link sections cresting the helix at the same time. By rotating the chain one complete turn, each link will rise to the crest twice and will therefore be faceted twice by the pressure plate on opposite sides. All links thus will receive two oppositely disposed flattened facets with one complete axial rotation of the chain.

In a preferred embodiment, the rope chain of this invention is a hollow rope chain. When making such a chain according to this invention, the chain may be of completely hollow wire or the hollow wire links may still have the soft metal or polymer core used in preparing hollow wire links, which cores can be removed subsequently by conventional means. When positioning the chain on the smooth surface, it is preferable that the chain be rendered inflexible. This can be achieved by not removing the forming wire used in assembling the rope chain with the links.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be discussed with reference to the drawings, in which - Figure 1 is a schematic view of a process for preparing the rope chain of the present invention; Figure 2 is a side elevation of a rope chain according to the present invention; Figure 3 is a view of the rope chain of Figure 3 along the axis as shown by the arrow in Figure ; Figure 4 is a plan view of an annular link in accordance with invention; and Figure 5 is an alternative elongated link in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to Figure 1 , the faceted jewelry rope chain of the invention can be prepared by taking a conventional rope chain 1 0 made according to the prior art while it is still held by the work wire 1 2 , which renders the chain 1 0 inflexible, and placing it on a smooth surface 1 4 lengthwise. A pressure plate 1 6 is then placed over the chain 1 0 , tightly squeezing chain 1 0 between the pressure plate 1 6 and smooth surface 1 4 . A predetermined force is applied to pressure plate 1 6 , while at the same time the plate is moved horizontally with respect to surface 1 4 , so as to roll the chain 1 6 between the surface 14 and pressure plate 16. The amount of pressure applied is predetermined, depending on the type of metal chain 10 is made of and whether it is solid, hollow or contains a soft core, and of course the desired surface area of the facet to be impressed on the chain, which is of course determined by the increment the pressure plate 16 is forced down on surface 14. On moving pressure plate 16 forward sufficiently to obtain one full rotation of chain 10, all the links in chain 10 will have impressed flat facets a, b, c, d, e and f along one crest of the double helix, as seen in chain 20 of Figure 2, and also facets a', b', c', d', e' and f on the other crest of the double helix, as illustrated in Figure 3.

All the individual links a-a ' , b-b', c-c ' , d-d', e-e ' and f-f have their originally arced outer surfaces flattened on opposite sides of the link, as shown in Figure 3, each link looking like Figure 4. It is quite obvious that the diameter of the faceted chain will be somewhat smaller than the diameter of the original chain prior to having facets compressed thereon. This, on the face of it, would appear to be undesirable. However, in the case of hollow rope chains, this proves to be a further advantage, as will now be explained.

In the manufacture of solid rope chains, particularly of very precious metals such as gold, the cost of materials is substantially higher than the labour cost, because of the significant weight of the gold per unit labour activity, i.e. looping one link into another and twisting it in its desired orientation. In the case of hollow gold rope chains, the cost of materials is significantly reduced. Since the hollow links are made from tubular material having metal wall thicknesses of about 0.05 mm, the reverse is the case, i.e. labour cost is high and the cost of materials is lower. The labour involved in making a smaller diameter rope chain is greater than that for making a larger diameter rope chain. This is because in a smaller diameter rope chain, more links have to be looped and twisted into their required orientation for the same length of chain than in the case of a larger diameter chain. Thus, by taking a conventional rope chain of the given diameter X and subjecting it to the process of this invention by impressing flattened facets on the crests of the links of the chain and reducing its overall diameter, one obtains a more expensive chain with minimal labour cost, since the pressing process according to this invention is primarily mechanical and can be automated and thus not labour intensive .

Furthermore, in accordance with the present invention, by utilising elongated links as shown in Figure 5 having their gaps on the short arc of the link, it is possible to obtain even further labour saving, because this link configuration requires fewer links per meter of chains of a given cross-section Y than does a corresponding chain made with round links of the same diameter Y.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure, which modifications do not constitute departures from the spirit and scope of the invention. - 9 -

Claims (10)

1. A faceted jewelry double helix rope chain made from tightly interfitting links of wire, each link having a small gap formed therein, characterised in that each link of the chain comprises two oppositely disposed facets of substantially equal size on the outer perimeter of said link, said facets being proximately normal to said gap, said rope having a substantially round diameter and furthermore having said two oppositely disposed substantially equal size facets of each link positioned on the crests of the double helix of the chain.

2. A jewelry rope chain in accordance with Claim 1, wherein said facets have been diamond cut or shaved to provide highly reflecting shiny surfaces.

3. A jewelry rope chain in accordance with Claims 1 and 2, having a cross-sectional diameter smaller than that of the chain from which it is made.

4. A jewelry rope chain as in Claims 1-3 wherein the chain links are hollow.

5. A jewelry rope chain as in Claims 1-4 wherein the chain links are elongated and their gaps are positioned in the shorter arc section of the link.

6. A process for making a fine jewelry rope chain having facets as in Claim 1 , comprising placing a rope chain in elongated orientation between two parallel plates and applying a predetermined amount of vertical pressure and horizontal motion to one of said plates, so that the said chain is compressed and made to rotate along its axis between said plates, thereby reducing the diameter of the chain and flattening the outer perimeter of the chain links cresting on the double helix.

7. A process as in Claim 6 wherein one of said plates remains stationary and vertical force and horizontal motion are applied to the other plate.

8. A process as in Claims 6 and 7 wherein the rope chain is a hollow rope chain.

9. A process as in Claims 7 and 8 wherein the flattened facets of the rope chain are diamond cut.

10. A process as in Claims 7-9 wherein the rope chain is made of elongated links having gaps positioned in the shorter arc section of the link. AGENT FOR APPLICANT