US3110328A - Dobby chain bar and linkage - Google Patents

Description

Nov. 12, 1963 w. a. HARRIS DOBBY CHAIN BAR AND LINKAGE Filed Aug. 21, 1962 z'yf.

INVENTOR. warren. B. Hon-r- L5 BY C United States Patent $110,328 DQBBY CHAIN BAR AND LHNKAGE Warren B. Harris, 6 Summer St, Millhury, Mass. Filed Aug. 21, 1962, Ser. No. 218,323 1 Claim. (1. 139-334) controlling the cloth pattern. Each bar is usually provided with one or two rows of closely spaced holes into which threaded metal pegs are screwed. These pegs are removably mounted in the various holes as required by the cloth pattern. The standard linkage comprises, as shown in FIG. 4 of the drawings, an S-shaped wire mounted in a hole in each bar, and the free ends of the link either touch or are embedded only slightly in the bar structure. However, the bar in cross-section has the shape of a frustum so that there is but little material in the bar structure to support the link strongly and prevent it from moving in its setting when under stress, and thus either breaking or damaging the bar structure and so interfering with the loom operation. This is particularly true where the bar is made of wood which is readily split by any twisting of the S-shaped link from its initial position. If the bar is made of a molded plastic, the loop end of the S-shaped link it not adequately supported, since the straight run of the link must be between the adjacent bar holes, and the free end of the loop is necessarily located in that wedge shaped bar close to one of the holes; the link, therefore, cannot be embedded adequately in the plastic material.

The primary object of this invention is to overcome the above-specified problem and to provide a bar structure which will hold each link securely and immovably positioned and thereby form a longer lived and stronger dobby chain bar. Further objects will be apparent in the following disclosure.

Referring to the drawings illustrating a preferred embodiment of the invention and a prior art form:

PEG. 1 is a fragmentary perspective view of one end of the bar;

FIG. 2 is a plan view, partly broken away, of two of the bars connected together by a linkage;

FIG. 3 is an end view of one of the bars; and

FIG. 4 is a fragmentary plan view of the ends of two standard wooden bars of the prior art.

Referring first to FIG. 4, the standard wooden bar as heretofore made comprises a wedged-shaped bar of wood, which may also have been made of molded plastic. The linkage comprises an S-shaped wire 12 passed through an obliquely arranged hole 13 located between the two rows of staggered dobby pin holes 14. After a straight wire has been passed through the hole 13, its two free ends 15 are bent downward into contact with the wood. The ends are interconnected by a chain link 16 to make an endless chain structure. If the bar is made of a molded plastic, these ends may be slightly embedded therein, but as is obvious from inspection of the drawing, these free ends are necessarily close to an adjacent peg hole 14 and so are not adequately embedded and supported against any turning or twisting action, with a resultant impairment of the structure under any lateral stress.

In accordance with my invention, as shown in FIGS.

djihfiz Patented Nov. 12, 1963 "ice 1, 2, and 3 of the drawings, I form the dobby chain bar of a suitable molded thermo-plastic or thermosetting plastic resinoid, such as a vinyl resin, polyethylene, cellulose acetate, a phenol-formaldehyde condensation product or other suitable material of adequate strength and wearability which is capable of being cast or molded to the required narrow elongated wedge shape by heat and/or pressure. The linkages 20, located near the bar ends are preferably made of wire and have a substantially S-shaped configuration. These are preferably shaped initially in their final forms and thus do not require a separate manual operation for shaping the loop ends after assembling the linkage wire. These shaped pieces are properly mounted in the mold, after which the resinoid is cast or molded around the wire in position to hold the wire. The central portion 21 of the link is properly shaped for location between the adjacent dobby peg holes 22 formed in the bar so as not to interfere with removably mount ing a set of screw threaded pegs 23 in selected holes of the bar. Reference may be had to my prior patents for a showing of the structure of the pegs which are arranged to project from the wide top face of the bar. Each link terminates in two oppositely projecting loops similar to loop 12 of FIG. 4 to which intermediate links are connected. The bar is illustrated as having two rows of peg holes in a staggered arrangement, but for some uses only one row of holes is required. The pegs project outwardly from the wide face of the bar and the narrow face parallel to the top is free for riding in the cylinder groove.

As a simple and adequate structural feature for supporting the linkage wire, I propose to shape the bar adjacent each of the linkage wires 20 so as to provide a large linkage strengthening mass of the molded material which will embed a substantial proportion of the wire therein and hold it immovably positioned. To this end, I provide the bar with an enlarged portion 24, preferably of substantially rectangular cross section, as shown in FIG. 3, which builds up the otherwise wedged shaped bar only adjacent to the link wire 20. The major portion of the bar is shaped as a frustum of a narrow elongated wedge and its converging side faces 25 (FIG. 1) are shaped to interfit with grooves and teeth on the driving cylinder, and there is usually room on the latter for these enlarged portions 24 to pass around the cylinder. Or, if desired, the cylinder may be cut away adjacent these short portions 24 to provide clearance therefor.

It will be seen by inspection of FIG. 3 that each end of the link wire is shaped as a loop and that the free end 26 extends to a considerable distance into the substance of the rectangular portion 24 of the bar without interfering with the dobby peg hole 22. If the enlarged portion 24 were omitted, the wire end could project into the bar only to a slight extent below the surface 25. Because of the added substance in the bar portion 24, the looped end of the wire is held securely in position by the large 7 mass of that molded resinoid and it cannot twist from its initial position. The link wires 20 are suitably connected by the links 28 (FIG. 2) and the dobby bar chain is adequately strong to satisfy all of its required functions of controlling the cloth pattern.

The portion 24 which embeds the wire linkage is shown as rectangular in transverse cross section with its lateral dimension equal to the thickness of the bar between the wide top face 28 and the narrow bottom face 29 of the bar (FIG. 3). The Width of the portion 24 is the same as the breadth of the wide face 28 of the bar. The length of the portion 24 longitudinally of the bar is preferably only a little more than the external diameter of the loop of the wire but long enough to give adequate support to the wire loop and yet it is short enough so that it will not strike the cylinder teeth and interfere with the normal use of the frustum portion of the bar between the faces 25 which drive the dobby chain. A preferred shape of bar which is usually about 8 or 10 inches long has its wide face 23 about /8 inch wide and its narrow face about inch wide, and the wedge bar is about inch thick. The projection 24 has a length of about /2 inch, which embeds adequately a wire loop of about inch external diameter. However, these dimensions may be changed within the scope of this invention, and particularly the corners and edges may be rounded. It will be appreciated also that the shapes and types of bar and linkage materials employed rnay be varied, as deemed necessary.

According to this invention, the linkage has a central link portion fully embedded in the wedge shaped bar substance and two looped shaped ends projecting oppositely, and wherein the loop ends are firmly embedded in enlarged laterally projecting portions of the bar which are no wider than the Width of the top face of the bar and have the same thickness as the bar, whereby the loop may have its end firmly secured in place Without interfering with the adjacent dobby pegs. The link 20 is preshaped of a hard drawn steel wire of high tensile strength, as distinguished from Wire heretofore used which had to be soft or annealed so that it could be readily bent into the required end loop shape after it had been assembled in the bar. Because a dobby chain may have a very great length, this prior use of a soft steel link has often resulted in a chain loop straightening out and the chain breaking apart. My prefabricated steel link of high strength avoids this problem. Other advantages in this new construction Will be apparent.

It is to be understood that the above disclosure of a preferred embodiment is not to be interpreted as imposing limitations on the appended claim.

4 I claim: A dobby chain comprising a set of parallel cross bars and interconnecting linkages, each bar being a body of a molded resinoid having its major portion shaped as a frustum of a narrow elongated wedge having parallel wide and narrow faces, said bar having at least one row of spaced peg holes, and dobby pegs removably mounted in selected peg holes and projecting laterally from the wide face of the bar, said linkage including an S-shaped hard drawn steel wire link of high tensile strength having a central portion embedded between adjacent peg holes in the bar near each end thereof and two projecting end loops terminating in free ends, said bar having near each end a linkage strengthening projecting portion of substantially rectangular cross-section transversely of the bar whose side faces lie substantially in the planes of said parallel bar faces and its lateral dimensions are substantially equal to the cross sectional width and breadth of the bar,

' said link end loops projecting oppositely with said free ends permanently and deeply embedded in said strengthenin-g projecting portions of the resinoid body near to but not intersecting dob'by peg holes, and said strengthening portions extending longitudinally of the bar only sufficient to embed and support the loop ends firmly without interfering with the normal useof the bar.

References Cited in the file of this patent UNITED STATES PATENTS

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