Abstract:
A jewelry bead has a rigid hollow body with an exterior wall of a first metal and a covering of a second metal whose color is different from that of the first metal. The covering overlies one or more selected areas of the wall so as to define an all-metal substantially level color pattern on the bead. A method of making the jewelry bead is also disclosed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to jewelry. It relates more particularly to striped metal beads for making beaded jewelry and to a method of making the beads.  
           [0003]    2. Background Information  
           [0004]    Beaded jewelry consists of one or more of beads strung on an elongated slender support, e.g. chain, wire, string, etc. to form necklaces, pedants, 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&#39;s clothing, thereby spoiling the appearance of the jewelry item.  
           [0005]    Therefore it would be desirable to be able to provide an all-metal bead which presents contrasting colors at its exterior surface.  
         SUMMARY OF THE INVENTION  
         [0006]    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.  
           [0007]    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.  
           [0008]    Yet another object of the invention is to provide a jewelry bead which presents alternating different color metal stripes at its exterior surface.  
           [0009]    A further object of the invention is to provide a method of making an all-metal bead with a substantially level contrasting color pattern at its exterior surface.  
           [0010]    Other objects will, in part, be obvious and will, in part, appear hereinafter.  
           [0011]    The invention accordingly comprises the steps and the relation of one or more of such steps with respect to each of the others, and 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.  
           [0012]    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.  
           [0013]    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. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The invention description below refers to the accompanying drawings, of which:  
         [0015]    [0015]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;  
         [0016]    [0016]FIGS. 2A to  2 D illustrate the method of making the bead in FIGS. 1A and 1B, and  
         [0017]    [0017]FIG. 3 is a view similar to FIG. 1A on a smaller scale, of a second bead embodiment. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    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  12   a  and  12   b  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.  
         [0019]    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  12   a  and  12   b.  As shown in FIGS. 1A and 1B, the stripe areas are widest at the bead equator and become progressively narrower towards holes  12   a  and  12   b  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.  
         [0020]    Refer now to FIGS. 2A to  2 D 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  20   a  and an inner surface  20   b  are 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  20   a  of tube  20  is of the selected first metal, i.e. gold or gold alloy, e.g. 10 karat or higher.  
         [0021]    The first step in the process is to apply masks M to the outer surface  20   a  of tube  20 . In the illustrated embodiment, the masks M are in the form of equally wide lengthwise masking strips spaced evenly around the circumference of surface  20   a.    
         [0022]    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  20   a  thereby forming a plurality of second metal stripe areas  18 ′ of selected thickness distributed around the circumference of surface  20   a.  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.  
         [0023]    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 .  
         [0024]    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  10   p  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  10   p  is separated from the remainder of tube  20  thereby forming the all-metal striped bead  10  with holes  12   a,    12   b  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.  
         [0025]    The particular shape of bead  10  as 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.  
         [0026]    While the drawing-down of tube  20  is 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  12   a,    12   b  at the bead poles and the alternating narrow and tapered gold and silver stripes  16 ,  18  extending between the poles 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.  
         [0027]    If a bead  10  with no holes  12   a,    12   b  is desired, e.g. for a brooch, earring, pin or the like, the holes  12   a,    12   b  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.  
         [0028]    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.  
         [0029]    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  12   a  and  12   b,  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.  
         [0030]    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.  
         [0031]    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.  
         [0032]    It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained.  
         [0033]    Also, certain changes may be made in carrying out the above method and 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.  
         [0034]    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