Striped metal beads
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A jewelry bead has a rigid hollow body with an exterior wall of a first metal and embedments of a second metal whose color is different from that of the first metal. The embedments overlie one or more selected areas of the wall so as to define an all-metal substantially level color pattern on the outside of the bead.

Pratt, Ronald (Cumberland, RI, US)
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International Classes:
A44C11/00; A44C27/00; (IPC1-7): A44C17/02
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Primary Examiner:
Attorney, Agent or Firm:
1. A jewelry bead comprising a rigid continuous thin-walled hollow body having an uninterrupted convex exterior surface of a first metal, and a conforming uninterrupted interior surface of said first metal having the same contour as the exterior surface, and an embedment in selected areas of said exterior surface of a second metal whose color is different from that of the first metal so as to define an all-metal, substantially level color pattern on said exterior surface of the bead.

2. The bead defined in claim 1 wherein said body is spherical.

3. The bead defined in claim 1 wherein said bead has a pair of opposite poles, and said color pattern is composed of a circumferential series of alternating first and second metal stripes, each stripe having opposite ends located adjacent to said pair of poles.

4. The bead defined in claim 3 and further including means defining a pair of diametrically opposite holes extending through said wall at said poles.

5. The bead defined in claim 3 wherein each stripe is tapered, being narrower at said ends than in between said ends.

6. The bead defined in claim 1 wherein said bead has a pair of opposite poles and said color pattern is composed of a series of alternating, circular first and second metal stripes centered on an imaginary line extending between said pair of poles.

7. The bead defined in claim 6 wherein the stripes are progressively narrower closer to the pair of poles.

8. The bead defined in claim 1 wherein said body in its entirety is of said first metal.

9. The bead defined in claim 1 wherein said body includes a base metal substrate with an outer cladding of said first metal comprising said outer surface.

10. The bead defined in claim 1 wherein the first metal is gold or an alloy thereof and the second metal is silver or an alloy thereof.

11. The bead defined in claim 1 wherein the first and second metal areas have a shiny finish.

12. The bead defined in claim 1 wherein said second metal areas have a matte finish.

13. The bead defined in claim 1 wherein the wall thickness of said body is less than 0.200 inch.

14. The bead defined in claim 13 wherein said wall thickness is equal to or greater than 0.003 inch.



This application is a continuation of Ser. No. 10/769,942 filed Feb. 2, 2004, now ______, which is a division of Ser. No. 10/126,821, filed Apr. 19, 2002, now U.S. Pat. No. 6,739,052.


1. Field of the Invention

This invention relates to jewelry. It relates more particularly to striped metal beads for making beaded jewelry.

2. Background Information

Beaded jewelry consists of one or more beads strung on an elongated slender support, e.g. chain, wire, string, etc. to form necklaces, pendants, earrings and the like. When the beads are of a precious metal such as gold, silver, platinum or alloys thereof, the entire exterior surface of each bead is usually of the same metal, e.g. gold, silver, etc. Therefore, each bead has essentially the same color over its entire surface area. This is because, due to the small size and round shape of the bead, it is very difficult, if not impossible, to mask the surface of the bead in order to plate or otherwise apply a contrasting color metal to the surface of the bead. Resultantly in order to provide a bead with contrasting colors, a non-metal coating of enamel, ceramic or the like is often applied to the metal surface of the bead. However when such coated beads are strung to form a piece of jewelry, the coatings tend to chip or wear away in time due to frictional contact with adjacent beads and with the wearer's clothing, thereby spoiling the appearance of the jewelry item.

Therefore it would be desirable to be able to provide an all-metal bead which presents contrasting colors at its exterior surface.


Accordingly, it is an object of the present invention to provide beads for making belts, necklaces, bracelets, anklets and other jewelry articles, which beads have exterior surfaces consisting of different, contrasting color metals.

Another object of the invention is to provide a jewelry bead whose exterior surface comprises at least two different metals which define a substantially level pattern at said surface.

Yet another object of the invention is to provide a jewelry bead which presents alternating different color metal stripes at its exterior surface.

Other objects will, in part, be obvious and will, in part, appear hereinafter.

The invention accordingly comprises the article possessing the features, properties and relation of elements, which are exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.

Briefly, the all-metal jewelry bead incorporating the invention has an exterior surface comprising at least two different contrasting color metals arranged in a pattern which gives the bead a distinctive exterior design. When the bead is strung with similar beads to form a necklace, bracelet or the like, the plural colored metal beads combine to give the overall jewelry item a particular pleasing appearance. Furthermore, since the beads are made entirely of metal, their distinctive surface patterns do not tend to degrade over time.

As will be seen presently, the all-metal surface pattern on each bead is formed during the bead manufacturing process. Therefore, the pattern is incorporated right into the bead rather than being applied to the bead after the bead is formed. Using the method described herein, all-metal beads can be formed with a variety of different contrasting color surface patterns to suit the needs and desires of the purchasers of fine jewelry.


The invention description below refers to the accompanying drawings, of which:

FIGS. 1A and 1B are side elevational and top plan views, respectively, on a very large scale of a striped metal bead incorporating the invention;

FIGS. 2A to 2D illustrate the method of making the bead in FIGS. 1A and 1B, and

FIG. 3 is a view similar to FIG. 1A on a smaller scale, of a second bead embodiment.


Referring to FIGS. 1A and 1B of the drawings, the subject bead shown generally at 10 is usually provided with a pair of opposite holes 12a and 12b for stringing the bead. The bead may be formed as a sphere as shown or it may have other shapes such as oblate spheroid, polyhedron, etc. as is well known in the bead manufacturing art.

The illustrated bead 10 has an exterior wall comprising different contrasting color metal areas 16 and 18 which are arranged to give the bead a distinctive exterior surface pattern. In the illustrative bead 10, the bead areas 16 are of gold and the bead areas 18 are of silver and the areas are shaped and arranged to define alternating gold and silver stripes which extend between the bead holes 12a and 12b. As shown in FIGS. 1A and 1B, the stripe areas are widest at the bead equator and become progressively narrower towards holes 12a and 12b at the bead poles. The illustrated bead has six each of the striped areas 16, 18. As we shall see, the stripe shape and number are determined during the manufacturing process. Basically, the bead 10 has a stripe pattern similar to the one found on many beach balls. Typically, bead 10 may have an outer diameter of 1-25 mm, or even larger.

Refer now to FIGS. 2A to 2D which depict the various steps involved in making bead 10. Bead 10 originates from a relatively long, large diameter tube 20 having an outer surface or wall 20a and an inner surface 20b as shown in FIG. 2A. Typically, tube 20 has an outer diameter of 1 inch or more and a wall thickness of 0.010 to 0.200 inch; the length of the tube is optional. Tube 20 may be made entirely of a selected first metal such as gold or gold alloy. Alternatively, in order to reduce costs, tube 20 may be composed of a radially inner substrate of an inexpensive base metal such as brass or copper and a radially outer cladding of the more precious first metal, i.e., gold or gold alloy. In either event, the outer surface or wall 20a of tube 20 is of the selected first metal, i.e. gold or gold alloy, e.g. 10 karat or higher.

The first step in the process is to apply masks M to the outer surface 20a of tube 20. In the illustrated embodiment, the masks M are in the form of equally wide length-wise masking strips spaced evenly around the circumference of surface 20a.

As shown in FIG. 2B, the masked tube 20 is then subjected to a plating operation during which a second metal, e.g. silver, is plated or CVD-deposited onto the unmasked areas of the tube surface 20a thereby forming a plurality of second metal stripe areas 18′ of selected thickness distributed around the circumference of surface 20a. Thus, following the plating step and the removal of masks M, the exterior surface of tube 20 will consist of lengthwise areas 18′ of the second metal separated by lengthwise areas 16′ of the first metal, i.e. alternating silver and gold stripes.

Next, as shown in FIG. 2C, tube 20 is subjected to a conventional drawing operation during which the tube is passed through a series of drawing dies which simultaneously reduces the diameter and wall thickness of tube 20 to form a drawn-down tube 20′ having a diameter which is more or less the same as the desired diameter of bead 10 in which case the wall thickness will reduce to about 0.003 inch or larger, with commensurate thinning of areas 18′. The same drawing operation will cause a corresponding extension and reduction in width of the stripe areas 16′, 18′ thereby producing an elongated tube 20′ whose stripe areas may be as narrow as 0.010 inch for a 1 mm bead 10.

Next, in accordance with FIG. 2D, the reduced diameter tube 20′ is subjected to a forming operation. During this forming operation, while rotating tube 20′ about its longitudinal axis A, the tube is advanced past a succession of hammers or dies indicated schematically by the arrows H in that figure. The hammers H drive progressively closer to the rotary axis A so that tube 20 is progressively deformed radially inward at spaced-apart locations along the tube as indicated in FIG. 2D as viewed from left to right. In other words, the first hammer H makes a slight circular deformation in the otherwise straight tube 20′. The tube with that circular deformation then travels to the second hammer which makes a slightly deeper deformation at the same place in the tube. That slightly deeper deformation is then advanced to the third hammer which deepens the deformation even more until the tube is deformed or crimped to such an extent that the wall of the tube 20 is necked down to an extreme as shown at D in FIG. 2D. At that point, the diameter of tube 20′ has been reduced to an extent that it is almost pinched off so that an end segment of the tube forms a more or less spherical photoshell 10P which is connected to the rest of tube 20′ only at the small annular neck remaining at the depression D. Tube 20′ is then advanced passed a cutter C which cuts the tube at the annular depression D so that protoshell 10P is separated from the remainder of tube 20 thereby forming the all-metal striped bead 10 with holes 12a, 12b as shown in FIG. 2D. Thus, as tube 20′ is advanced through the forming machine, successive beads 10 are cut from the end of the tube until the tube is used up.

The particular shape of bead 10 are determined primarily by the shapes of the hammers or dies H and the cross-sectional shape of tube 20′. While the illustrated bead 10 is spherical, many other bead shapes are possible, e.g. cube, oblate spheroid, etc.

While the drawing-down of tube 20 are shown in FIG. 2C elongates and narrows the gold areas 16′ and the silver areas 18′ at the surface of tube 20, the forming or crimping of the reduced diameter tube 20′ as shown in FIG. 2D progressively narrows those stripes even more in the areas of the crimps so that when each bead 10 is separated from the remainder of tube 20′ by cutter C, that bead has the holes 12a, 12b at the bead poles and the alternating narrow and tapered gold and silver stripes 16, 18 extending between the holes as shown in FIGS. 1A and 1B. Furthermore, since the areas 16′, 18′ are drawn-down together, the areas 18′ are embedded right into the drawn-down tube 20′ wall so that there is no discernable change in wall thickness of the bead from stripe to stripe. In other words, the stripe patterns are substantially level all around the bead. After cleaning, the result is a bead 10 having alternating gold and silver stripes 16, 18 with a shiny finish.

If a bead 10 with no holes 12a, 12b is desired, e.g. for a brooch, earring, pin or the like, the holes 12a, 12b at the poles of the bead are hammered shut enabling a closed bead to be soldered or otherwise secured to a fixture or fastening device.

A particularly desirable contrasting color visual effect is produced if, following the formation of each all-metal striped bead 10, the bead is subjected momentarily to an acid bath, e.g. nitric acid, which etches the surfaces of the silver areas 18. This has at least two beneficial effects. First, it removes any residual silver that may have been deposited on the surfaces of the gold areas 16. Secondly, it gives the silver areas 18 a matte finish which contrasts sharply with the shiny or glossy finish of the gold areas 16 which are not affected by the acid bath.

While the illustrated bead 10 has a surface pattern composed of alternating different color metal stripes, it is also possible to produce beads with other surface patterns. For example, if the tube 20 of a first metal, e.g. gold, is plated with a lengthwise series of equally narrow circumferential rings of a second contrasting color metal, e.g. silver, after the tube is drawn and formed as indicated in FIGS. 2C and 2D, the resultant bead 22 shown in FIG. 3 will have at its surface alternating, circumferential gold and silver rings 24 and 26, respectively, which are narrowest midway between the holes 12a and 12b, i.e. at the bead equator, and which become progressively wider as they approach those holes. This is because the original narrow rings will become equally wide during the drawing process of FIG. 2C. Then, during the forming process of FIG. 2D, in the areas of the crimps, the rings will become progressively wider.

The illustrated plated tube 20′ for making the illustrated bead 10 has equally wide areas 16′,18′. Using appropriately dimensioned, shaped and placed masks M on tube 20, it is possible to provide a tube 20′ with different width areas 16′, 18′ or areas with non-straight, e.g. sinusoidal, zigzag, etc., shapes which will result in various, plural color patterns at the surface of the resultant bead.

Also, while the illustrated bead 10 has a surface pattern composed of gold and silver, it is also possible to use other different color metals, such as platinum, copper, etc. to produce other design effects wholly of metal at the surface of the bead. Furthermore, the original tube 20 can be plated with several different color metals by successive masking operations to produce beads with more elaborate all-metal surface designs or patterns.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained.

Also, certain changes may be made in the constructions set forth without departing from the scope of the invention. Therefore, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention described herein.