GB2118821A - Snake chain - Google Patents

Abstract

A snake chain of improved durability containing less metal than a conventional snake chain, is formed from a plurality of metal blanks 5 linked together by means of metal linking elements 6 wherein each metal blank is provided with two holes 7 located opposite one another and each linking element is provided with two arms 8 and is substantially dumb- bell shaped. <IMAGE>

Description

SPECIFICATION Snake chain The present invention relates to snake chain and to an improved method of making it.

"Snake chain" is a term given to chain formed from individual stamped-out, substantially circular pieces of metal bent and held together by metal linking pieces in such a manner as to form a flexible continuous length of chain. Such chain is used for key chains, light switch chains and bags, necklaces, etc.

At present, such snake chains is formed from a plurality of circular blanks of metal which are provided with three holes spaced equidistantly from one another. The outer edge of each blank is bent at substantially 900 to the body of the blank to form a dish-shaped element. Each dish-shaped element is linked to another such element by means of a linking element which comprises a piece of metal provided with three equidistantly spaced arms, the arms of each linking element being bent at approximately 900 to the body of a linking element so that each arm can pass through one of the holes of a first dish-shaped element and then through one of the holes of a second dishshaped element, thereby linking two dish-shaped elements together.Thus, it can be seen that the arms of two linking elements pass through the holes of one dish-shaped element and the dishshaped elements are held together in a flexible manner since when the arms of the linking element have passed through the holes of the second dish-shaped element they are flared and cannot be easily removed.

We have sought to provide a snake chain which, although using less metal than is conventional, results in a snake chain which is more durable.

Accordingly the present invention provides a snake chain formed from a plurality of metal blanks linked together by means of linking elements wherein each metal blank is provided with two holes located opposite one another and each linking element is provided with two arms and is substantially dumb-bell shaped.

By using blanks and linking elements of the above configurations, it is possible not only to save at least 30% metal as compared with the conventional process but also to produce a snake chain which has increased durability compared with conventional snake chains.

Metal is saved by using the new process since there is less wastage when stamping out twoarmed linking elements as compared with threearmed linking elements from metal strips.

Furthermore, in conventional snake chains in which the linking element has three arms, when the finished snake chain is bent, any two of the arms will tend to impose a limit on the amount of bending that is possible; whereas when the snake chain of the present invention, which has only two arms opposite one another, is bent, its bending is either inhibited by both arms in which case virtually no bending takes place or it is uninhibited and can be bent into a band with a smaller radius than the band of the conventional snake chain.

Due to the inherent nature of the individual elements of the snake chain and to gravitational forces, the snake chain of the present invention will invariably settle into a position when no arms hinder the bending.

In an alternative embodiment, the metal blank may be provided with two subsidiary holes which are located opposite one another and further increase the amount of metal saved without deleteriously affecting the strength of the resultant chain.

The elements of the snake chain of the present invention are linked together in a similar manner to that set out above for known snake chains.

The present invention is further illustrated in the accompanying drawings, wherein: Figure 1 is a plan view of prior art elements for making snake chain; Figures 2a and 2b are plan views of alternative embodiments of elements for making snake chains in accordance with the present invention; Figure 3a is an exploded side view of prior art snake chain; Figure 3b is a side view of prior art snake chain; Figure 4a is an exploded side view of snake chain in accordance with the present invention; and Figure 4b is a side view of snake chain in accordance with the present invention.

As shown in Figure 1, the elements which are formed into prior art snake chain consists of a circular blank 1 and a linking element 2. The circular blank 1 is provided with three holes 3 through which arms 4 of the linking element 2 can pass.

Figures 2a and 2b show alternative embodiments of the elements which are formed into snake chain of the present invention and they consist of a circular blank 5 and a linking element 6. The circular blank 5 is provided with two holes 7 through which arms 8 of linking element 6 pass.

The circular blank 5 of Figure 2b is also provided with additional holes 9 which reduce the amount of metal needed to form the circular blank 5 without adversely affecting its strength.

Figures 3a and 3b show how the arms 4 of linking element 2, when bent, pass through the holes of two circular blanks 1 which have been bent to a dish-shaped configuration, to form prior art snake chain.

Similarly, Figures 4a and 4b show how the arms 8 of linking element 6, when bent, pass through the holes of two circular blanks 5, which have been bent to a dish-shaped configuration, to form snake chain of the present invention.

The snake chain of the present invention is assembled in the following manner. The circular blank 5 and the linking element 6 of Figures 2a and 2b are punched out from a brass strip. The circular blank 5 is then passed to a moulding machine in which it is pressed into the dishshaped configuration shown in Figures 4a and 4b and the linking element 6 is passed to a bending machine in which its arms 8 are bent to form a linking element 6 of the configuration shown in Figure 4a. The arms 8 of the so-shaped linking element 6 are then inserted through the holes 7 of the dish-shaped blank 5 to form a set.

The snake chain is formed by inserting the arms 8 of the linking element 6 of a first set through the holes 7 of the blank 5 of a second set; the arms 8 of the linking element 6 of the second set are then inserted through the holes 7 of the blank 5 of a third set. This process is repeated until the desired length of snake chain has been built up.

Finally, the thus formed snake chain is passed through a die set in which the diameter of the chain is decreased so that the holes 7 in the blank 5 become smaller and thus the arms 8 of the linking element become firmly secured.

Claims (7)

1. A snake chain formed from a plurality of metal blanks linked together by means of metal linking elements wherein each metal blank is provided with two holes located opposite one another and each linking element is provided with two arms and is substantially dumb-bell shaped.

2. A snake chain as claimed in Claim 1, wherein each metal blank is substantially circular.

3. A snake chain as claimed in Claim 1 or 2, wherein each metal blank is provided with two further holes located opposite one another to further reduce the amount of metal needed to form the blank.

4. A snake chain as claimed in Claim 1 substantially as herein described and with reference to the accompanying drawings.

5. A method of assembling a snake chain of the type claimed in Claim 1 comprising: (a) punching a plurality of metal blanks and metal linking elements from a metal strip so that each metal biank-has two holes located opposite one another and each linking element has two arms and is substantially dumb-bell shaped; (b) bending the outer edge of each blank at approximately 900 to the body of the blank to form a dish-shaped element; (c) bending the arms of each linking element at approximately 900 to the body of the linking element and passing the two arms of the linking element through the two holes respectively of a first dish-shaped element and through the two holes respectively of a second dish-shaped element thereby linking two dish-shaped elements together; (d) repeating steps (b) and (c) until the desired length of snake chain is formed; and (e) passing the thus formed snake chain through a die set to reduce its diameter so that the holes in each-dish-shaped element become smaller and the arms of each linking element become firmly secured.

6. A method as claimed in Claim 5 which is continuous.

7. A method as claimed in Claim 5, substantially as herein described and with reference to the accompanying drawings.