US 3098369 A
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Description (OCR text may contain errors)
y 1963 A. BURLESON ETAL 3,098,369
COMPRESSIVE STOCKING Filed Dec. 1, 1961 INVENTORS %im)7511r/esan Mark N //0/)fle5 BY 61/154401, 644M United States Patent 3,098,369 COMPRESSIVE STOCKING Aaron Burleson and Mark Nicholas Holmes, Burlington,
N.C., assignors to Burlington Industries, Inc., Greensboro, N.C., a corporation of Delaware Filed Dec. 1, 1961, Ser. No. 156,459 4 Claims. (Cl. 66-178) This invention relates to knitted compressive or support garments, and in particular to circularly knit ladies con-n pressive stockings.
The invention involves circularly knit nylon fabric having bare, elastomeric polyurethane yarn knitted into alternate courses of the fabric, to provide strong and durable compressive garments exhibiting unique and desirable properties. The elastomeric polyurethane yarns utilized are non-foamed, being generally single strand but composed of either multi-filament or monofilamen-t yarns which are commercially available for example from E. I. du Pont de Nernours and Company under the names Fiber K and Lycra, from the US. Rubber Co. as Vy-rene, and from the Firestone Tire & Rubber Co. as Spandex.
A principal object of the present invention is the provision of novel tubular compressive fabrics and garments exhibiting superior two-way stretch, resulting from the incorporation therein of el-astomeric polyurethane yarn and the manner of its incorporation. Related objects are the provision of sheer ladies compressive stockings, having excellent hand and feel.
A further object of the invention is the provision of compressive garments adapted to be circularly knit at high speed, utilizing simple and conventional circular knitting machines and procedures. Specifically, the garments are particularly suited for two-feed and four-feed knitting.
Another object is to provide ladies compressive stockings having bare, elastomeric polyurethane yarn in corporated therein, in such manner that the elastomeric yarn does not detract from the appearance of the finished stockings. Further objects will be in part evident and in part pointed out hereinafter.
The invention and the novel features thereof may best be made clear from the following description and the accompanying drawings, in which:
FIGURE 1 is a diagrammatic side view of a compressive stocking embodying the invention, and
FIGURE 2 is an enlarged diagrammatic view of the leg fabric of the stocking of FIGURE 1, showing the fabric in stretched and idealized condition for the sake of clarity.
In the drawings, the stocking S illustrated in FIGURE 1 includes the usual welt 10, shadow welt 12, leg portion 14, heel 16, foot portion 18 and toe 20. The structure of the fabric may be readily understood from a detailed description of the knitting of the stock-ing.
By way of example, the stocking is knit on a conventional 400-needle circular knitting machine provided with two feeds. Except possibly for the heel 16 and toe 20, the entire stocking may be knit two-feed. Initially, the welt is knit with two ends of 40 denier filament crimped or texturized nylon yarn, and the shadow welt 12 is then similarly knit with two ends of 40 denier textur- -ized yarn. When the shadow welt is completed, the machine shifts into knitting of the body or leg portion 14. For this purpose, the feed at the main knitting station is changed to 40 denier raw pirn nylon yarn, and the feed at the auxiliary knitting station is changed to 20 denier filament raw pirn nylon yarn. A bare 70 denier elastomeric polyurethane yarn is supplied at the auxiliary knitting station with the 20 denier nylon yarn, and is knitted in therewith, The polyurethane yarn is tensioned and stretched approximately 225% as it is fed to the auxiliary knitting Patented July 23, 1963 station of the machine, so that a relaxed length of about 12 to 14 inches of polyurethane yarn, stretched to approximately 40 inches, is fed into each course along with 40 inches of nylon yarn.
The two-feed knitting above described proceeds through the leg portion until ankle tightening begins at the usual point. Ankle tightening may be elfected by increasing the tension on the respective nylon body yarns, thereby decreasing the length fed per course and the size of the knitted loops. In accordance with the present invention, however, the tension of the polyurethane yarn is not altered, but remains constant throughout the leg. This permits the use of a very simple feeding and tensioning device for the polyurethane yarn, which may be a feed wheel geared directly to the machine drive to provide a uniform 12 inches of relaxed yarn per course, and since this feed remains constant throughout the stocking, a simple mechanical arrangement is permitted.
At the completion of the leg portion 14, the machine shifts into the heel 16 in conventional fashion, and at the completion of the heel, the foot portion 18 may be knitted two-feed in the same manner as is the leg 14. As in the leg, the relaxed length of polyurethane yarn fed per course of the foot is uniform and the same as in the leg, whereby machine design and operation is greatly simplified. At the completion of the foot, two-feed knitting may be terminated and the toe 20 knitted single-feed in conventional fashion. It will be recognized that the heel 16 and toe 20 may be knitted either single-feed or twofeed, and may be knitted with a single yarn, or reinforced.
FIGURE 2 represents the leg and foot fabric, shown in stretched and idealized condition. As there shown, courses 22 and 2.4 are knit of the same 40 denier raw pirn nylon yarn, and the alternate courses are knit throughout of 20 denier raw pir-n nylon yarn 26 and the 70 denier polyurethane yarn 28.
In the knitting above described, the nylon yarn is knit to the size of a conventional stocking, and the polyurethane yarn greatly extended, so that on relaxation of the polyurethane yarn, the dimensions of the stocking are considerably less than those of a conventional stocking. The approximate shape of the stocking in as-knitted condition may be as illustrated in FIGURE 1 of the drawing, wherein the leg and foot portions are substantially cylindrical. When the stocking is placed on the log, it is necessarily stretched to conventional dimensions, and the combination of yarns gives excellent fitting properties and compressive support. The compressive effect of the fabric is uniform and elfective in the longitudinal as well as in the coursewise direction. In the as-knit condition, and also when the stocking is stretched on the leg, the polyurethane yarn is substantially embedded in the fabric, and the yarn exposed at the surface is predominantly nylon, whereby the appearance of the fabric approximates that of a nylon fabric. When stretched on the leg under wearing conditions, the density of each 40 denier nylon yarn course approximates the density of the alternate courses, including the 20 denier nylon yarn and the extended 70 denier polyurethane yarn.
The stocking may be boarded and finished in the form illustrated in FIGURE 1, or if desired it may be boarded and finished in more conventional form, wherein the upper section of the leg portion is Wider than the ankle section thereof. The polyurethane yarn being thermoplastic, the stocking is readily shaped in the usual boarding operation. The stocking exhibits excellent dyeing and finishing characteristics.
The above example may be varied, in order to produce a slightly heavier fabric, by knitting through the leg portion with 50 denier raw pirn yarn at one feed, and with 30 denier raw pirn yarn and 70 denier polyurethane yarn at the other feed. A similar stocking may be knitted on a 340-needle circular knitting machine, supplying 20 denier raw pirn yarn with 140 denier poly-urethane yarn to alternate courses, and 50 denier raw pirn yarn to the intervening courses. In some constructions, monofilament nylon yarn may be utilized, and thrown yarn containing twist may be utilized in place of raw pirn yarn. It will be appreciated that various modifications may be made in the invention described herein, without deviating from the scope and intent thereof as set forth in the appended claims.
We claim: 1. A knit compressive stocking knit throughout at least the leg portion thereof with nylon body yarn,
said portion having bare elastomeric polyurethane yarn knitted in alternate courses to give compressive support in the "longitudinal and coursewise directions, said polyurethane yarn being embedded in the fabric so that the yarn exposed at the surface is predominantly nylon, the body yarn in the same courses with the polyurethane yarn being lighter in weight than the body yarn in the intervening courses, whereby the appearance of the fabric approximates that of a nylon fabric. 2. A knit compressive stocking as set forth in claim 1 in which the relaxed length of the polyurethane yarn knitted into alternate courses is substantially constant throughout said leg portion.
3. A knit compressive garment knit throughout at least a portion thereof with nylon body yarn,
said portion having bare elastomeric polyurethane yarn knitted in alternate courses to give compressive support in the longitudinal and coursewise directions, said polyurethane yarn being embedded in the fabric so that the yarn exposed at the surface is predominantly nylon, the body yarn in the same courses with the polyurethane yarn being lighter in weight than the body yarn in the intervening courses, whereby the appearance of the fabric approximates that of a nylon fabric. 4. A knit compressive garment as set forth in claim 3 in which said polyurethane yarn is knitted in every stitch of alternate courses together with the body yarn.
References Cited in the file of this patent UNITED STATES PATENTS 2,396,166 Faucette Mar. 5, 1946 2,430,860 Cairns Nov. 18, 1947 2,949,023 Holmes Aug. 16, 1960 2,962,885 Knohl Dec. 6, 1960 3,016,726 Lawson Ian. 16, 1962