US 2961738 A
Description (OCR text may contain errors)
,- v- 9,1960 1;. mum
TEXTILE PRODUCT "Filed Nov: 3,19
INVENTOR LELAND E THOMAS ATTORNEY tag? United States Patent TEXTILE PRODUCT Leland F. Thomas, Snow Hill, N.C., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Nov. 2, 1955, Ser. No. 544,446 '3 Claims. (Cl. 2s-s1 This invention relates to a method of joining tow in the textile industry. In processing tow, particularly that prepared from synthetic fibers, such as fibers spun from a nylon, a polyester, or polyacrylonitrile, discontinuities in the tow line may occur frequently when it becomes necessary to cut out lengths of tow which are below standard for some reason. Heretofore this has been done simply by tieing the two ends into a knot. When the yarn is later converted from tow into top, it is necessary to remove the knot before the tow passes into the converter or other type of cutter or breaker. The tow is made of up to several hundred thousand fine filaments, and the knot is usually very difiicult to untie. For this reason, it is customary practice to cut out the knot. Since the synthetic fiber is relatively expensive, the amount of waste in a year becomes an economic consideration of considerable moment.
Another disadvantage of the knots is the tow bundle is that twists and foldovers result from about 50% of the knots and, if these are not straightened out ahead of the converter, unevenly cut lengths in the top occur. The inconvenience and waste of time in straightening out the foldovers and twists also add to the manufacturing cost.
It is, therefore, an object of the present invention to provide a means for connecting tow line ends in which waste is substantially avoided when the tow is subsequently disconnected at the junction point.
Another object of the present invention is the provision of means for connecting tow line ends in which twists and foldovers in the tow line are substantially avoided.
Other objects will appear as the description of the invention proceeds.
These and other objects are accomplished by stitching the tow ends together preferably with a chain stitch which can readily be unravelled. In one embodiment of the invention, the two bundles of tow are laid evenly one upon the other with the ends pointing in the same direction and stitched together forming a projecting seam. In another embodiment, the two ends are overlapped and stitched through the overlapping area. The stitching is preferably accomplished by a two-thread chain stitch of dilferent colors; although, a single chain stitch is operable. The tow may be sewed as indicated above or a tape may be placed transversely on one or both sides of the tow ends and stitched along the tape. The arrangement of the tapes and stitching will be more readily understood by reference to the accompanying drawing.
In the drawing, Figure 1 represents a diagrammatic plan view of two ends of tow stitched together with a tape on each side.
Figure 2 is a section along the line 22 of Figure 1.
Figure 3 is a section similar to Figure 2 in which only one tape is used.
Figure 4 is a section similar to Figure 2 in which no tapes are used.
Figure 5 is a diagrammatic plan of two overlapping ends of tow which have been stitched without tapes.
Figure 6 is a section similar to Figure 4 but stitched with a single-thread chain stitch.
Patented Nov. 29, 1960 In all the figures, 1 represents the tow, 2 indicates the stitching, and 3 denotes the tape which is placed transversely to the tow near the ends. This tape may be a strip of any suitable paper, film, or fabric and if desired of a contrasting color so that the seam may be readily observed during the travel of the tow in the machine.
.As indicated above, the tow ends may be placed one upon the other and stitched to form a seam as shown in Figure 1, or the tow ends may be overlapped and stitched as shown in Figure 5. The stitching is done on a conventional sewing machine, such as class 157-3 Singer, which is normally used for sewing burlap, canvas, and similar woven fabrics. The stitch length should be rather long; i.e., from about 3 /2 to 8 stitches per inch. A clearance under the presser foot of about of an inch is satisfactory for most tow. It will be apparent, however, that these figures will vary depending on the denier and number of filaments in the tow being sewn. Likewise, the choice of the number of tapes, if any are used, is largely dependent on the same factors. When it is desired separate the tow ends again, the appropriate thread, usually the colored one, is pulled to unravel the stitching. If a lock stitch is used the stitching has to be cut or the section of tow bearing the stitching has to be cut out.
The present invention represents a distinct saving in the processing of tow, both in the saving in material and in time. In addition, it has been found that the strength of the seam is unexpectedly great. Even though the filaments of the tow run in a generally parallel direction without any twist or any cross filaments, the stitching holds and does not pull out under considerable tension. Groups of filaments may be pulled loose from the tapes with relative case but the strength of the bond across the entire tow bundle is more than sufiicient for all normal processing steps and the filaments do not pull loose from the seam when a force is applied to the entire bundle. Foldovers and twists in the two line are substantially eliminated by the present invention and when a chain stitch is used the seam is eliminated without waste.
It will be apparent that many widely different embodiments of this invention may be made without departing from the spirit and scope thereof, and therefore it is not intended to be limited except as indicated in the appended claims.
1. Two bundles of tow made up of a multitude of smooth synthetic substantially parallel filaments without significant twist or cross filaments, one end of one of the bundles overlapping an end of the other bundle and a series of thread stitches transversely disposed through the overlapping portions of each bundle, the said stitches being about 3 /2 to 8 per inch.
2. The product of claim 1 in which the stitches are chain stitches.
3. The product of claim 1 in which a reinforcing tape is stitched on at least one side of the tow bundles.
References Cited in the file of this patent UNITED STATES PATENTS 1,074,580 Tyrrell Sept. 3, 1913 1,105,309 Samuel July 28, 1914 1,198,810 Arbib Sept. 19, 1916 1,519,091 Lea Dec. 9, 1924 1,714,928 Sigoda May 28, 1929 2,605,603 Willis Aug. 5, 1952 2,648,891 Pollrnan Aug. 18, 1953 FOREIGN PATENTS 2,818 Great Britain of 1908 398,854 France June 16, 1909