Chain link, chain made therefrom and method of chain manufacture

A link and a chain formed therefrom, wherein the links comprise a shaft portion having first and second opposing ends defining therebetween a longitudinal axis for the link; an enlargement portion connected to the shaft portion at the first end, the enlargement portion having a width which is greater than a width of the shaft portion at the first end; and a mandorla shaped portion having first and second apertures therein, the mandorla shaped portion being connected to the shaft portion at the second end, and the apertures being shaped so as to prevent the enlargement portion from passing therethrough.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a novel chain link, chain made therefrom, 
and a method of chain manufacture. The link is particularly useful for the 
manufacture of jewelry chain, formed, for example into ornamental 
necklaces, bracelets, belts, etc. 
2. Description of the Prior Art 
Jewelry chains serve principally a decorative purpose, and are used in a 
variety of ways. For example, jewelry chains may be used for necklaces, 
bracelets, belts, etc. Typically, chains consist of a series of links 
looped together to form the chain. 
Various jewelry chains comprising plural loop-type links and methods of 
assembly have been proposed in the past. For example, in U.S. Pat. No. 
4,448,017 Stark provides a chain loop element comprising a wire ring 
crimped together to form a teardrop shape. One end of the teardrop shape 
has a loop, and the other end has two parallel wires. Plural links are 
joined together by passing the two parallel wires of one link through the 
loop portion of an adjacent link. An ornament, such as a bead, etc. is 
attached to the end of two parallel wires passed through the adjacent 
link, so as to secure the links together. Such links, and chains 
manufactured therefrom, are somewhat undesirable, since the ornaments used 
for securing the links together protrude from the chain and may tend to 
catch clothing, etc. of the user and/or others. In the event that the 
ornaments used comprise precious or semiprecious stones, their protrusion 
from the chain tends to expose them to undesirable abuse, possibly causing 
their loss. Additionally, due to the round nature of both the teardrop 
loop and the two parallel wires passing therethrough from the adjacent 
link, there is no way to adjust the bend and stretch characteristics of 
the chain to suit various uses. Furthermore, the crimping, or other means 
used to form the teardrop shape from the wire ring, is somewhat 
unattractive, and merely provides the operating function needed for 
completing the chain links. 
Accordingly, there is a need for a new link and chain made therefrom that 
allows adjustment of the bend and stretch characteristics of the chain so 
as to suit various uses, and which takes not only the functional 
characteristics of the chain into consideration, but is enhances the 
aesthetic qualities of the chain. 
SUMMARY OF THE INVENTION 
In accordance with he principles of the invention, a link for forming a 
chain comprises a shaft portion having first and second opposing ends 
defining therebetween a longitudinal axis for the link; an enlargement 
portion connected to the shaft portion at the first end, said enlargement 
portion having a width which is greater than a width of the shaft portion 
at the first end; and a mandorla shaped portion having first and second 
apertures therein, the mandorla shaped portion being connected to the 
shaft portion at the second end, and the apertures being shaped so as to 
prevent the enlargement portion from passing therethrough.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Initially, it is noted that although the illustrated preferred embodiment 
of the invention is in the context of a chain for jewelry purposes, the 
invention is equally applicable for making chain for use in areas other 
than jewelry, such as belts for machinery and gears. 
As shown in FIG. 1, the new link 2 comprises a shaft portion 4, a 
enlargement portion 8, and a dual-apertured mandorla shaped portion 6. 
Shaft portion 4 has one end connected to the enlargement portion, such as 
a ball 8, and its other end connected to the mandorla shaped portion 6. 
Portion 6 has first and second apertures 10 and 12, respectively, formed 
therein, due to the presence of a cross bar 14. Note, as will be explained 
in a moment, cross bar 14 is only connected to mandorla portion 6 at one 
of its inside edges. 
Link 2 may be formed by hand using pieces of round and half-round wire, but 
in the preferred embodiment, link 2 is formed using casting techniques. 
Casting techniques for forming links, especially those useful for jewelry, 
are well know to those of ordinary skill in the art, and therefore 
description of making the casting mold will be largely omitted. However, 
it is noted that when making the model for the casting a round wire was 
used for making shaft portion 4 and cross bar 14, and half-round wire was 
used for making the mandorla shaped portion 6. Alternatively, bezel wire 
having a "c" shaped cross-section could be used for making the model of 
the mandorla portion 6, so as to maintain the appearance of substantial 
size for the link, while reducing its weight and the amount of precious 
material used to make the link. The mandorla portion 6 and the ball 8 were 
then soldered to opposite ends of shaft 4 and the end of the mandorla 
portion 6. Next, the link tip 16 is cut so as to separate the tip of the 
link in half, along the horizontal axis 18. The link is then "opened" up 
using two pairs of pliers, each half of the mandorla portion 6 being held 
by one of the pliers. Pressure is then exerted so as to separate the two 
halves until they are as shown in FIG. 2. The link is opened until there 
is enough space between the free end of cross bar 14 and the inside wall 
of the other half mandorla portion 6, so as to permit the passing of a 
shaft portion 4 therethrough. This completes manufacture of the model to 
be used for manufacturing all subsequent links by casting. The casting can 
be accomplished in accordance with any of several well known techniques. 
The above mentioned link is the basic shape for the production of a chain. 
There are alterations that can be made to the shape of the link to 
facilitate various methods of manufacturing, and some of these methods 
will be discussed later at the end of this section. 
To assemble the chain, there is a repeating pattern of links that is 
established. Initially, a link 22 has it's shaft portion inserted into the 
first aperture 20a of a link 20. Next, the shaft portion 4 of a link 24 is 
inserted into the first aperture 22a of link 22, and then positioned so 
that links 20 and 24 are substantially parallel to one another and their 
mandorla and enlargement portions 6 and 8 are oriented in the same 
direction. Next, the shaft portion 4 of a link 26 is inserted through a 
first aperture 24a of link 24 and then through the second aperture 20b of 
link 20, and positioned so that links 22 and 26 are substantially parallel 
to one another and their mandorla and enlargement portions 6 and 8 are 
oriented in the same direction, and so that links 20, 22, 24 and 26, when 
so arranged, form a parallelogram shape. After each link has a shaft 
portion inserted in both its apertures, it can be closed using a pair of 
pliers, and then it's tip 16 is soldered. For forming a chain of any 
desired length, the parallelogram shaped pattern established by links 20, 
22, 24 and 26 is repeated with as many additional links as needed. 
A technique for attaching a clasp (not shown), to finish the chain for 
jewelry, is shown in FIG. 4. To attach the clasp, first, the chain must be 
made continuous by connecting its free ends together. This is accomplished 
by connecting the end of the chain with the balls 8 into the appropriate 
ones of apertures 10 and 12 in the other end of the chain. Then, the last 
three mandorla portions 6 can be soldered closed. Next, for a set of four 
adjacent links, the shafts 4 are connected to the apertures 10 and 12 
through which they pass, by e.g., soldering. This connects the four 
adjacent links together to form a unified base to receive the clasp. Next, 
the unified piece is cut in half along an axis 20. Then, on one end of the 
chain a clasp tongue is attached, and on the other side, enough metal is 
burred out on it's underside to accommodate the clasp box. The box is then 
soldered in place, a safety is attached, and then the finished necklace 
(or bracelet, etc) is cleaned, stamped and polished. Alternatively, 
instead of unifying four links, a model of these unified four links can be 
cast and used, thereby saving a lot of clasp assembly time. 
The size and shape of the shaft, the wires used to form the apertured 
mandorla portion and the diameter of the ball are all critical to the 
proper functioning of the chain. If the ball is too small, it will fall 
through the apertures and the chain would fall apart. If the diameter of 
the shaft is too large, it will inhibit the flexibility of the chain by 
making it "stiff". A large diameter for the wire forming the mandorla will 
decrease the open space, or width, in which the shaft portion moves. This 
decrease in moving space makes the shaft lock-up and prevents any further 
movement along the longitudinal axis of the chain. If a smaller diameter 
round wire is used for forming the mandorla, more moveable space is 
created therefore making the chain "looser" and giving more flexibility 
along the longitudinal axis. While control of the movement along the 
longitudinal axis is desired so that one can regulate this characteristic 
for the specific utility of the chain, for it's use as jewelry, there is a 
critical wire diameter size. This is due to the metals used in jewelry. 
Gold, silver and platinum are soft metals and can only take a certain 
amount of stress or impact before becoming deformed. Too small of a 
diameter will result in a very loose chain but more importantly, the wire 
will be too frail, and can be easily bent and deformed through normal use 
of the chain. Simply put, it will bend itself out of shape and will loose 
its regular repetitive pattern. Too large a diameter wire will result in a 
limited flexibility along the longitudinal axis, which inhibits its 
usability as a jewelry chain. If the chain is not flexible, then it will 
be uncomfortable and potentially dangerous to the wearer. 
The length of the shaft is also critical. If it is too short it will not 
have the length needed to allow the chain to have flexibility along an 
axis perpendicular to the longitudinal axis. Not only will the flexibility 
in the perpendicular axis be inhibited but flexibility along the 
longitudinal axis will be inhibited as well. This is due to the critical 
angles created in the parallelogram shaped pattern between the ball-shaft 
connection and the top inside aperture. By preventing the aperture from 
having the ability to slide further down the shaft, the ball-shaft 
connection is locked into the inner wedge of the aperture, thus decreasing 
the amount of movable space. This inhibits a lot of the movement of the 
chain on the perpendicular axis as well as the longitudinal axis. Just as 
the size of the diameter and length of the shaft is critical to 
manufacture a chain having certain desired characteristics, so to is the 
size of the aperture to the size of the shaft. If the aperture is large 
compared to the shaft diameter, then there will be greater mobility. If 
the aperture is too small there will be less mobility. The sizes of the 
shaft and the aperture are completely co-dependant. Any alteration of one 
of the critical sizes will affect the mobility of the chain and will 
require an alteration of all other critical sizes to return the link to 
it's desired mobility. For the purpose of jewelry, the chain must be 
flexible enough along it's longitudinal axis to wrap around a wrist and 
flexible enough along an axis perpendicular to the longitudinal axis, 
i.e., a top-bottom axis, to curve around a neck. Torsion of the chain is 
also controlled by the sizes of the shaft and the aperture. The larger the 
shaft size and/or the smaller the aperture size, the less torsion the 
chain will have. The smaller the shaft size and/or the larger the aperture 
size, the more torsion the chain will have. 
The ability to manipulate the size of different portions of the link, such 
as the diameter and length of the shaft, and the dimensions of the 
apertures, etc, allows for a desired change in the size of a portion of 
the link for producing a deliberate affect in the chain's characteristics, 
such as its flexibility, stretch, etc. For maintaining the remaining 
desirable characteristics of the chain, a corresponding change should be 
made in the size of the remaining portions to return the chain 
characteristics back to acceptable ranges. For example, to scale-up all 
the link dimensions to make a larger size link might make for a necklace 
which is too heavy to be worn as jewelry. To reduce the diameter of the 
shaft wire will allow for a smaller length of the shaft, a smaller 
aperture and therefore a smaller ball. This will reduce the mass (weight) 
of the link while maintaining its size. 
Representative dimensions for a "medium" sized link are as follows: 
Diameter of ball 8=3.25 mm; Diameter of shaft portion 4=1.45 mm; Length of 
shaft portion 4=6.5 mm; Length of mandorla portion 6=14.7 mm; Diameter of 
cross bar 14=1.28 mm; Length of cross bar 14=3.3 mm; Mandorla sides=high 
halfround wire 1.35 mm high and 2.37 mm wide; and the longitudinal 
dimension of apertures 10 and 12 is approximately 5 mm. 
Thus, what has been shown and described is a novel link for a chain, a 
chain made therefrom, and a method of chain manufacture which fulfills all 
the stated desires and objects therefore. Changes, modifications, 
variations and other uses and applications of the subject invention will 
become apparent to those skilled in the art after considering this 
specification and its accompanying drawings, which disclose preferred 
embodiments thereof. For example, although a rounded shape wire was used 
for making links 2, rectangular shaped wire could have been used. 
Additionallly, the mandorla shaped portion 6 could have been formed to 
have a more rectangular (instead of almond) shape, and instead of having a 
ball 8 at the end of shaft 4, a square shaped enlargement could have been 
used. 
Furthermore, although a preferred method of manufacturing has been 
described, alternate methods are also possible. for example: 
1) Make the same shaped model, however, instead of cutting it open at tip 
16 of the link, it's opened at the portion where the mandorla joins the 
shaft portion 4. The assembly would be the same as the embodiment 
described, however, instead of soldering together the tips 16 of mandorlas 
6, the portion near the shaft is soldered closed. 
2) Make the same shaped model, however, do not cut it at all. Instead, pry 
the link open enough to allow the passage of the ball through the 
apertures, and then crimp it closed. 
3) Take the same shaped model, however, the ball is cut off. Drill a hole 
completely through the ball. Then solder onto the end of the shaft a piece 
of wire with a slightly smaller diameter than the hole in the ball. The 
length of the wire should be a little bigger than the diameter of the 
ball. Do not make any cut into the mandorla side of the link. Then to 
assemble; slide the shafts through the apertures and slide the balls onto 
the small wire on the top of the shafts. Then solder the balls onto the 
shaft. 
All such changes, modifications, variations and other uses and applications 
which do not depart from the spirit and scope of the invention are deemed 
to be covered by the invention which is limited only by the claims which 
follow.