US2171995A - Method of forming twisted chain links - Google Patents

Description

p 1939- G. s. SCHMIDT, JR' I 2,171,995v

METHOD OF FORMING TWISTED CHAIN LINKS Filed July 2, 1936 )ATTORNEY Patented Sept. 5, 1939 UNITED STATES IVIETHOD OF liORllllIlNG TWISTED CHAIN LINKS George Small Schmidt, Jr., York, Pa.,

to American Chain 85 Cable Company,

assignor Inc.,

a corporation of New York Application July 2, 1936, Serial No. 88,547

'7 Claims.

The present invention relates to a novel method of forming twisted chain links such as curb links and the like.

I-Ieretofore, it has been the practice to make such links in the form of fiat closed loops and then to twist opposite ends of each link in opposite directions. In the ordinary curb link it is desirable to provide a twist of about 90 degrees. In other words, the plane of one end of the link is disposed substantially at right angles to the plane of the other end. There are other forms of links in which such relation of the opposite ends of the links must be carried to a greater angular degree. For example, in Letters Patent of the United States granted to John R. Reyburn, No. 2,053,047 dated September 1, 1936, there is disclosed a link particularly adapted for use in cross chains applied to traction wheels in which the angular relation of the opposite ends may be anywhere from 100 to 180 degrees, while the side elements of the link are widely spaced apart. In the ordinary process of forming curb links, as the opposite ends are relatively twisted the sides of the link are gradually drawn together and if the twisting is carried far enough the sides are brought into actual contact with each other.

An object of the present invention is to provide a method of and means for forming twisted chain links without causing the side elements of the link to move inwardly toward each other.

Another object of the present invention is to provide a method of forming a twisted link or a chain of such links without subjecting the opposite ends of the link to relative torsion.

With the above-named objects in view and such others that may appear hereinafter I shall now describe my improved method and a preferred embodiment of the means for carrying out said method and thereafter the novelty and scope of the invention will be set forth in the claims.

In the acompanying drawing;

Figure 1 is a plan View of a link before being subjected to my novel forming method;

Figs. 2, 3 and 4 show a chain of links formed by my process, illustrating the links in plan, side elevation and end elevation, respectively;

Fig. 5 is a plan view of part of the means for forming the links; and

Fig. 6 is a view in side elevation of the link forming means.

I have discovered that a so-called twisted link may be formed by a simple bending process without applying a torsional twist to opposite ends of the link, thus avoiding the crowding of the side elements of the link toward each other even though the relative angular relation of the opposite ends of the link be carried up to 180 degrees. I have found that if a link in the form of a flat oblong loop be bent transversely but on an axis that is disposed obliquely with respect to the major axis of the loop, the result will be a link which has the appearance of having been twistedexcept that the sides of the link will remain in widely spaced relation; also that the relative angularity of the opposite ends of the link may be varied in accordance with the obliquity of the axis of the bend with respect to the original major axis of the link.

In Figure l, I show a flat link I!) in the form of an elongated loop comprising a pair of parallel side elements H which are connected by a pair of semi-circular end elements l2. The major axis of the link before bending is indicated by the line A-A. In order to convert this flat link into a twisted link it is bent transversely about an axis B-B which is obliquely disposed with respect to the axis A-A. This causes a shift of the major axis in the bent link to the line C-C which is the line of pull of a chain of such links. In plan the link will have a substantially diamond shaped appearance, as shown in Fig. 2, with two opposite sides convex and the the other two sides concave. In the links illustrated in Figs. 2 to 4 inclusive, these sides are all approximately semi-circles and in side elevation as well as in end elevation the links have the projected form of the figure 3. The figure 8 is obviously longer in Fig. 3 than in Fig. 4 because the links are longer than they are wide but otherwise they are quite symmetrical.

Viewedendwise, that is, in the direction of the axis C -C, it will be observed that one end of the link lies in the plane DD, while the opposite end of the link lies in the plane E--E and in the particular link illustrated, these planes form an angle of approximately 120 degrees to each other. In other words, a structure is obtained which corresponds to a link whose opposite ends have been relatively twisted 120 degrees, with this important difference, however, that because of my method of forming the links the side elements are not drawn together but remain in widely spaced relation to each other. Obviously, the angularity of one end with respect to the other may be increased or decreased by correspondingly increasing or decreasing the depth of the bend. In the particular link illustrated, the axis B-B forms an angle of about degrees with the axis AA. If this angle is decreased there will be a smaller angular. departure of axis C-C from axis A-A and the bent link will be longer.

A convenient means of carrying out my forming method is illustrated in Figs. 5 and 6. I show at l5 a die having the shape of a substantially semi-cylindrical trough. However, the depth and form of the trough may be varied in accordance with the desired shape of the bent link. The die is formed with flat shoulders I6 and H disposed respectively at opposite sides of the trough and these shoulders have rounded edges where they merge into the trough. Projecting, from each shoulder is a pair of pins l8 which serve to position the link on the die. It will be observed that the position of the pins on the shoulder ll is advanced with respect to the po-.

sition of the pins on the shoulder 16 so that when a link IE] is bridged across the trough it will be positioned by these pins at the desired angle with respect to the die. In order to permit of form ing the links of a chain after they have been interlinked the die block is formed with a. recess 20 to receive the link that is to be bent next and a similar notch 2! is formed in the shoulder IT to receive a link that has already been bent. Cooperating with the die 15 is .a punch 22 which is in the form of a blade adapted to force the link downward between the shoulders into the trough of the die. This punch is provided with a cylindrically rounded lower end corresponding in general to the curvature of the trough and is also provided with slots 23 and 243 in opposite sides thereof to clear the links which may be lying in the recesses 2|] and 21 respectively. The punch and die are preferably operated in a punch press, although obviously my method could be carried out by any power or manual means for causing relative movement of the punch and die.

The term twisted link as used in the foregoing specification and also in the claims will be understood to refer to a link which has the appearance of having been twisted although actual twisting is avoided by my method. It will be understood that the side elements of a link formed by my process may be truly helical if the proper form of die and punch is used and in this respect the links would then differ from the ordinary curb link in which the side elements do not consist of parallel helices.

While I have described a preferred embodiment of the means for carrying out my process it will be understood that this is to be taken as illustrative and not limitative of my invention and that I reserve the right to make various changes in form, construction, and arrangement of parts without departing from the spirit and scope of my invention as defined in the following claims. It will also be understood that the form of the original fiat link is not limited by the showing in Fig. 1 and that while in said figure the side elements correspond in length substantially to the end elements so that after the link has been bent all of the curved parts "twisted link out of an oblong flat link which consists in bending the flat link into helically distorted U-form by applying a bending force thereto in a direction normal to the plane of the flat link at points on a line disposed obliquely with respect to the major axis of the fiat link.

3. The method of forming a link simulating a twisted link which consists in making an oblong flat loop, and bending this loop into helically distorted U-form by applying a bending force thereto in a direction normal to the plane of the fiat loop at points on a line disposed obliquely with respect to the major axis of the flat loop.

4. The method of forming a link simulating a twisted link out of an oblong flat link which consists in bending said fiat link cylindrically about the line of intersection of a plane extending parallel to the plane of said flat link .and a plane normal to the plane of said fiat link and intersecting the major axis of said fiat link.

5. The method of forming a link simulating a twisted link out of an elongated flat loop which consists in bendingthe side strands of said loop into helical paths about a common axis lying in a plane extending normal to said flat loop and intersecting the major axis of said flat loop.

6. The method of forming a link composed of a closed loop of metallic wire of substantially saddle form with substantially parallel arcuate side elements and substantially parallel arcuate end elements, all of said arcuate elements being of substantially the same radius but with the axis of the side elements forming an acute angle with the axis of the end elements, which consists in bending an elongated flat loop having'parallel side strands and semi-circular ends into a helically distorted U-form.

7. The method of forming a link composed of .a closed loop of metallic wire of substantially saddle like form with substantially parallel arcuate side elements and substantially parallel arcuate end elements, all of said elements being of substantially the same radius, which consists in bending an elongated flat loop having parallel side strands and semi-circular ends cylindrically about an axis lying in a plane parallel to the plane of the loop and extending at an angle with respect to the major axis of the flat loop.

GEORGE SMALL SCHMIDT, JR.

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