US3732708A

US3732708A - Knit pile carpet fabric

Info

Publication number: US3732708A
Application number: US00164526A
Authority: US
Inventors: J Troy
Original assignee: Fieldcrest Mills Inc
Current assignee: FIELD CREST CANNON Inc
Priority date: 1971-07-21
Filing date: 1971-07-21
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

Abstract

A warp knit pile fabric and method of making the same wherein a base fabric is formed from spaced rows of warpwise extending chain stitches interconnected by laid in weft yarns, and through which chain stitches pile yarns are looped in overlying relation to the laid in weft yarns. Ribbon-like strands of plastic film material are utilized for forming the weft yarns and/or the chain stitch yarns, with all such ribbon-like strands being provided by slitting respective sheets of plastic material concurrently with the knitting operation.

Description

United States Patent 1191 Troy 1 1 May 15, 1973 154] KNIT PILE CARPET FABRIC 3,503,106 3 1970 P611 et al ..28/72 3,626 989 12/1971 Herd 1...l39/1l [75] Inventor: James E. Troy, Eden,N.C. 3,645,299 2/1972 Eichler 1 139/11 [73] Assigneez Fieldcrest Mills Inc, Eden NC 3 ,110,905 11/1963 Rhodes "139/391 X 22 Filed: July 21 1971 FOREIGN PATENTS OR APPLICATIONS 21 App]. 164 52 1,041,544 5/1953 France ..66/202 Primary Examiner-James Kee Chi [52] US. Cl. ..66/191, 66/8656fib616/6l62/52g2, Atmmey Parrot, Be", Seltzen Park & Gibson [51] Int. Cl..H..D04b 9/14, D04b 21/02, DO lb 23/08 57] ABSTRACT [58] Field of Search ..66/190-l95 4 84 85 78/ CS 72 A warp knit p1le fabnc and method of making the s 5 1i f same wherein a base fabric is formed from spaced rows of warpwise extending chain stitches intercon- [56] References Cited nected by laid in weft yarns, and through which chain stitches pile yarns are looped in overlying relation to UNITED STATES PATENTS the laid in weft yarns Ribbon-like strands of plastic film material are utilized for forming the weft yarns j i and/or the chain stitch yarns, with all such ribbon-like 3:213:646 10/1965 Van F atten... .:I::::::::: ::::66/l91 Strands being Provided by slitting respective Sheets of 2,934,924 5 1960 Herrnstadt ..66/191 Plastic material Concurrently with the knitting p 2,968,085 1/1961 Matthews 1 66/191 X lion- 2,596,246 5/1952 Johnson et al ..28/1 CS 3,453,816 7/1969 Radoff ..66 202 x 4 Clams, 6 Drawing Figures F 1 K110111100 1,1 1 611111111 filllllilltllmw mittttlllltlnm 111111111111 lllllll 11111111111111111111 ("1111111111111119 illllll 1311213011014 01: 14M 1 T1NG 1' 1\ @1111111111911 9 slur WI a lltlllliilllllilllllln,

11111111111111 P 1 1 1W1] ,1111un1n11111111 11 1 \flMll'liilllllllllllllD. f lm mlillllllmm .1 I f1 6% "'7 mm 11153111 1111. I

SHEET 1 [1F 3 DIRECTION o1 Km mG bHZECTlON OFKN nnNG PATENIEDHAYI 5 I975 PATENTEU HAY] 973 SHEET 2 [IF 3 bREcmoM OF KNHTMGV blzecmon OF KN \TT] NG- KNIT PILE CARPET FABRIC The use of warp knit construction is well known in the manufacture of pile fabrics such as rugs and carpets, see for example Clark U. S. Pat. No. 3,140,592. Conventionally, warp knit pile fabrics have heretofore utilized jute yarns for the laid in weft yarns and cotton or rayon for the chain warp yarns. Such fabrics have oftentimes exhibited a buckling problem, as for example when wall-to-wall carpet formed thereof is installed, due to varying humidity conditions readily causing elongation, primarily of the laid in jute yarns. This problem is increasingly evident wherein the carpet is laid over a surface, such as concrete, that has not been provided with a suitable moisture barrier surface thereon.

Furthermore, during knitting, the attendant knots present in the jute yarns oftentimes causes the jute yarns to hang up in the guide tubes therefor, thus causing attendant stoppage of the knitting machine. Also, the presence of knots in the jute yarns create points of interference with the pile yarns, which also inherently have knots therein, further contributing to machine stoppage and/or defective pile fabric.

With the foregoing abbreviated background in mind, it is the primary object of this invention to provide a warp knit pile fabric construction which facilitates the knitting thereof and which fabric has built-in properties to overcome the aforementioned buckling problem.

This is accomplished by using ribbon-like strands of plastic film material for the laid in weft yarns and/or the warp chain yarns with such plastic film material being hydrophobic and being arranged so as to provide an enhanced moisture resistant backing to the knitted pile fabric. The laid in weft yarns are preferably of such width and are so arranged as to be in somewhat overlapping side by side relationship to maximize their coverage factor on the backside of the fabric. Contributing to the moisture resistance of the backside of the fabric, in the preferred form of the invention, are the ribbonlike strands of plastic film material also serving as the chain warp yarns.

For reasons to be pointed out in more detail later, it has been determined that the knitting operation is greatly facilitated with a much lower down time factor when rolls of plastic film material, slit concurrently with the knitting operation, are utilized as the source for the laid in weft yarns and chain warp yarns. It has been determined that one conventional roll of plastic film material about the size of a beam of yarn utilized heretofore, contains a length thereon equivalent to the length of many beams of conventional yarns. It has also been determined that it is a simple matter to splice in a new roll of film material when the previous roll is exhausted, merely by utilizing a pressure-sensitive tape to join the trailing and leading ends of the film material. Thus, with the instant invention, a knot-free base fabric can be readily made which, as indicated earlier, results in greater efficiency of the knitting machine and, at the same time, a product with enhanced advantages.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIG. 1 is an enlarged plan view ofthe pile face of one embodiment of the improved warp knit pile fabric provided with sinuous weft yarns of ribbon-like strands of plastic film material interconnecting spaced warpwise rows of chain stitches of fibrous yarns with pile yarns looped through the stitches;

FIG. 2 is an inverted plan view looking at the back of the fabric of FIG. 1, but showing a few additional rows of chain stitches broken away and omitting the pile yarns and portions of some of the ribbon-like strands of weft yarn for purposes of clarity;

FIG. 3 is a perspective view of the fabric of FIG. 1 omitting portions of both the pile yarns and the weft yarns in the right-hand portion thereof, and omitting portions of the pile yarns only in a medial portion thereof;

FIGS. 4 and 5 are views similar to the respective FIGS. 1 and 2 showinga second embodiment of the im-" proved warp knit fabric in which both the chain stitches and the weft yarns are formed from ribbonlike strands of plastic film material; and

FIG. 6 is a schematic view ofa warp knitting machine showing an arrangement for slitting sheets of plastic film material, being withdrawn from respective rolls thereof, into ribbon-like strands concurrently with the knitting operation.

Referring more specifically to the drawings, two embodiments ofthe improved warp knit pile fabric are shown in FIGS. 1, 2 and 3, and in FIGS. 4 and 5, respectively, which may be formed on a conventional warp knitting machine suitably modified to carry out the method of this invention, as will be later described. The warp knitting machine is shown schematically, designated at M in FIG. 6, and may be of the type generally disclosed in said Clark US Pat. No. 3,140,592, the disclosure of which is incorporated herein by reference.

The first embodiment of the improved warp knit pile fabric shown in FIGS. 1, 2 and 3 comprises a base fabric having a group of warp yarns 10 forming weftwise spaced, substantially parallel, warpwise extending rows of chain stitches 10a. In this particular embodiment, the chain stitch warp yarns may be of any conventional type, such as rayon or cotton yarns, for example. The base fabric also comprises a group of novel weft yarns l1 laid in the chain stitches with each weft yarn extending in a zig-zag or sinuous manner generally warpwise of the fabric and interconnecting adjacent warpwise rows of the chain stitches 10a. The weft yarns 11 are especially formed so as to facilitate knitting of the fabric and to provide a moisture resistant backing thereto. To this end, the weft yarns 11 are in the from of ribbonlike strands of hydrophobic plastic film material, and each ribbon-like strand of weft yarn 11 is relatively thin and is of a width much greater than its thickness. It is preferred that the ribbon-like strands of weft yarn 11 are each about 2 to 3 mils thick and have a width in the range of about to 1 l5 mils. It is also preferred that the ribbon-like strands forming the weft yarns II are made from polypropylene or polyester plastic material.

Each weft yarn I1 is laid in and interconnects a plurality of the rows of chain stitches 10a. Although each ribbon-like strand'of weft yarn 11 may extend between only three rows of chain stitches 100, as is the case with the conventional weft yarns of the conventional warp knit pile fabrics, such as that shown in FIG. 16 of said Clark patent, it is preferred that each ribbon-like weft yarn interconnects four or more adjacent rows of chain stitches so as to increase the stability of the pile fabric, especially during processing of the same following the knitting of the pile fabric. Such processing may include steaming, washing and/or dyeing the pile fabric. Also, a suitable backing material, such as high density foam rubber or latex, may each applied to the back of the pile fabric after knitting the same. It is apparent that bowing and/or skewing or other distortion of the warp knit pile fabric should be avoided during such processing, especially during the applying of any form of back-sizing material to the warp knit pile fabric, so that the spaced warpwise rows of interconnected chain stitches a will be disposed in perpendicular relation to the transverse rows of spaced apart chain stitches defined thereby. As best shown in FIG. 2, each ribbonlike strand of weft yarn 11 embraces four rows of chain stitches 10a. Although the ribbon-like strands of weft yarn are rolled upon themselves where they are looped partially around portions of the chain stitches, it is to be noted that each weftwise length or portion is laid in through four weftwise spaced stitches in a substantially flat condition so that the weftwise flat surfaces of each strand largely extend in a plane substantially parallel with the plane of the back of the base fabric.

Although each ribbon-like strand of weft yarn 11 em braces four adjacent rows of chain stitches 10a, the number of weft yarns 11 is the same as the number of warpwise rows of chain stitches, with the bights of adjacent weft yarns being looped around immediately adjacent portions of interconnected warpwise extending rows of chain stitches. Consequently, portions of four adjacent weft yarns 11 are disposed in overlapping substantially side by side relationship at and between immediately weftwise adjacent chain stitches; i.e., major portions of adjacent ribbon-like strands extend in side by side partially overlapping relationship and the ribbon-like strands of weft yarn cover more than 50 percent of the area between the spaced rows of chain stitches 10a.

As shown in FIGS. 1 and 3, pile yarns 12 are looped through the rows of chain stitches 10a, with the lower bights of the pile yarns being disposed above and being substantially shielded by the ribbon-like strands of weft yarn 11. A separate pile yarn 12 is provided for each warpwise row of interconnected chain stitches 10a, and each pile yarn 12 generally extends in a substantially warpwise direction. However, each pile yarn zig-zags back and forth between two immediately adjacent rows of chain stitches 10a so that a row of pile loops 12a is formed from a respective pile yarn 12 between each adjacent pair of warpwise rows of stitches 10a. Pile yarns 12 are usually relatively large bulky yarns as compared to the warp yarns 10, and the spacing between adjacent warpwise rows of chain stitches 10a, as well as the size of each stitch in each warpwise row are largely determined by the mass or size of the pile yarns 12. It is to be noted in FIG. I, in particular, that two lower bight portions of adjacent pile yarns 12 are looped through each chain stitch, The height or length of each pile loop 120 is determined by the height of pile wires or formers (not shown) over which the pile yarns 12 are looped during the knitting operation, as disclosed in said Clark patent. Although the pile loops 12a are shown in FIG. 3 as being of substantially the same height or length throughout the pile fabric, it is apparent that the loops may be of varying heights and that some or all of the loops may be severed to form cut pile tufts therefrom in selected areas of the pile fabric or throughout the pile fabric, as desired.

From the foregoing description, it can be seen that, by providing the base fabric ofthe warp knit pile fabric of the first embodiment with ribbon-like strands of hydrophobic plastic film material serving as the sinuous weft yarns ll laid in and interconnecting the warpwise rows of continuous chain stitches 10a, a moisture resistant backing is provided covering more than 50 percent ofthe area between the'warpwise rows ofchain stitches 10a, thus substantially eliminating the problems of elongation and consequent buckling of the fabric when installed as wall-to-wall carpet in areas subject to substantial humidity variation. In actual fabrics formed as in FIGS. 1, 2 and 3, it has been determined that up to percent of the area between the spaced warpwise rows of stitches has been covered by weft yarns ll of ribbon-like strands of hydrophobic plastic film material.

Referring now to FIGS. 4 and 5, a second embodiment of the fabric is shown, which is devised to further facilitate knitting the same and to further enhance the moisture resistance of the base fabric. Essentially, the fabric of FIGS. 4 and 5 is quite similar to the fabric of FIGS. 1, 2 and 3. Therefore, in order to avoid repetitive description, the elements of the fabric shown in FIGS. 4 and 5 will bear the same reference characters as similar elements of the fabric shown in FIGS. 1, 2 and 3, with the prime notation added. The second embodiment of the improved warp knit pile fabric shown in FIGS. 4 and 5 differs from the first embodiment in that, instead of the warpwise rows of interconnected chain stitches 10a being formed from a conventional type of yarn, as is the case with respect to the first embodiment the groups of warp yarns 10 are each in the form of a ribbon-like strand of hydrophobic plastic film material of substantially the same type as the ribbon-like strands forming the sinuous weft yarns 11'. In other words, the entire base fabric may be formed of ribbon-like strands of plastic film material with conventional pile yarns 12' being looped through the stitches 10a and to form the raised loops 12a. Although the bight portions of the stitches 10a formed of the ribbon-like strands of warp yarn l0, and'the adjacent portions of the strands which extend through the latter bight portions, are necessarily crowded together or rolled upon themselves, it will be observed in- FIGS. 4 and 5 that substantial portions of each stitch between their points of interlacement extend in substantially flat condition largely in a plane substantially parallel with the plane of the back of the base fabric. Thus the ribbon-like warp yarn strands 10 forming the stitches 10a, and theribbon-like weft yarns 11', cover at least about percent of the back of the base fabric to provide an enhanced moisture resistance thereto. In a typical fabric formed as in FIGS. 4 and 5, it has been determined that up to percent of the entire area of the back of the warp knit pile fabric has been covered by the ribbon-like strands of plastic material forming both the warp yarns l0" and the weft yarns 11.

Another advantage in providing weft yarns formed of ribbon-like strands of hydrophobic plastic film material in the base fabric of the warp knit pile fabric, which advantage is further enhanced by also providing chain stitch warp yarns 10 formed of ribbon-like strands of hydrophobic plastic material, is that the ribbon-like strands of hydrophobic plastic material shield the major portions of the lower bights of the

pile yarns

12 or 12, as the case may be, to substantially prevent any back sizing materials, such as latex or high density foam rubber, from penetrating through to the upper surfaces of the lower bights of the pile yarns during application of the back sizing material to the warp knit pile fabric as is desirable.

According to the method of this invention, the weft yarns 11 of the first embodiment of the fabric (FIGS. 1-3), and both the weft yarns l1 and the chain stitch warp yarns of the second embodiment of the fabric (FIGS. 4 and 5), are formed concurrently with the knitting of the fabric in each instance, thereby obviating the need for preparing and winding yarns onto bobbins, spools or beams before they can be fed to the knitting machine, and also obviating the necessity for piecing up the trailing ends of the corresponding yarns to the leading ends of yarns from a new beam or from individual yarn sources, as the case may be, whenever the supply therefor is exhausted as has been customary heretofore.

A suitable arrangement of equipment for carrying out the method of this invention is shown schematically in FIG. 6, such equipment being arranged, in this instance, for knitting the second embodiment of the fabric shown in FIGS. 4 and 5. As shown in FIG. 6, pile yarns 12' are drawn from a suitable source shown in the form of a beam 12b, and the pile yarns then may pass upwardly and in a substantially horizontal path through a suitable pile yarn tension means 12c. From tension means 12c, pile yarns 12' pass downwardly to the warp knitting machine M where they pass through the usual pile yarn guides associated with the knitting instrumentalities M, not shown in the present drawings but being fully disclosed in said Clark US. Pat. No. 3,140,592.

In order to form the ribbon-like strands of plastic material serving as the chain stitch warp yarns 10 and the sinuous weft yarns ll concurrently with the knitting operation, sheets of plastic film material 10b, 11b are withdrawn from respective rolls 10c, 11c and then pass through respective film slitting means 14, 15 which slit the respective sheets of plastic film material 10b, 11b into a plurality of parallel ribbon-like strands forming the respective warp yarns and weft yarns 10', 11'. The warp and weft yarns 10', 11 pass directly from the respective film slitting means l4, 15 to the warp knitting machine M while the warp knitting machine is in operation and is forming the warp knit pile fabric generally designated at F in FIG. 6. The fabric F may be taken up by any suitable take-up means 16. The width of the sheets 10b, 11b is about the same as the width of the fabric F being knit, and suitable means, not shown, may be provided for applying the desired amount of tension to the sheets 10b, 11b.

Each slitting means l4, 15 may include any suitable means for slitting the corresponding sheet of plastic film material into the desired widths of ribbon-likestrands, such as a plurality of thin parallel circular cutters or stationary blades spaced the desired distance apart from each other. Since film slitting means are well known, a detailed illustration and description of the film slitting means l4, 15 is deemed unnecessary.

In forming the warp knit pile fabric of FIGS. 1, 2 and 3, it is apparent that the method may be carried out utilizing apparatus such as that described with respect to FIG. 6 with the exception that a source of conventional yarns would be used in place of the sheet of plastic film material 10b, the roll 10c, the film slitting means 14 and the ribbon-like strands 10' of plastic film material.

It is thus seen that there is provided a method of making a warp knit pile fabric in which a base fabric is knit from a group of warp yarns and a group of weft yarns by forming spaced warpwise extending rows of interconnected chain stitches from the warp yarns while laying in the weft yarns to interconnect the rows of chain stitches, during which pile yarns are looped through the chain stitches above the laid in weft yarns with the pile yarns extending upwardly from the base fabric, and wherein at least one sheet of plastic film material, being withdrawn from a roll thereof, is slit into ribbon-like film strands concurrently with the knitting operation, while utilizing the ribbon-like film strands being formed as the source of supply for at least one of the groups of yarns forming the base fabric; i.e., the ribbon-like film strands being formed serve as the source of supply for either the weft yarns or the warp yarns or both the weft yarns and the warp yarns.

It is apparent that the method greatly facilitates the knitting of the pile fabric by eliminating the need for preparing and feeding conventional yarns to the warp knitting machine as the source of supply for the weft yarns and/or the warp yarns. Also, when a roll of the plastic film material is exhausted, it is a simple matter to replace the same with a new roll and to splice the leading end of the new roll to the trailing end of the sheet of plastic film material then approaching the corresponding film splitting means 14 or 15 by means of a strip of pressure-sensitve tape. In the event of individual strands 10' or 11 becoming parted unintentionally, they also may be spliced by utilizing pressure sensitive tape to join the trailing and leading ends of the ribbonlike strands, thus avoiding knots in the base fabric and resulting in greater efficiency of the warp knitting machine M.

In the drawings and specification, there have been set forth preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

l. A warp knit pile fabric comprising a base fabric having a group of warp yarns forming spaced rows of warpwise extending chain stitches and a group of weft yarns laid in the chain stitches with each weft yarn extending in a zig-zag manner and interconnecting adjacent rows of the chain stitches, and pile yarns looped through the chain stitches above said laid in weft yarns and extending upwardly from said base fabric; characterized' in that at least said group of weft yarns is formed of ribbon-like strands of plastic film material each about 2 to 3 mils thick and of a width within the range of about to l 15 mils with each of said ribbonlike strands interconnecting at least four adjacent rows of said chain stitches and with the strands being positioned with major portions of adjacent strands in side 3. A warp knit pile fabric according to claim 1- wherein said ribbon-like strands are of polypropylene plastic material.

4. A warp knit pile fabric according to claim 1 wherein said ribbon-like strands are of polyester plastic

Claims

1. A warp knit pile fabric comprising a base fabric having a group of warp yarns forming spaced rows of warpwise extending chain stitches and a group of weft yarns laid in the chain stitches with each weft yarn extending in a zig-zag manner and interconnecting adjacent rows of the chain stitches, and pile yarns looped through the chain stitches above said laid in weft yarns and extending upwardly from said base fabric; characterized in that at least said group of weft yarns is formed of ribbonlike strands of plastic film material each about 2 to 3 mils thick and of a width within the range of about 80 to 115 mils with each of said ribbon-like strands interconnecting at least four adjacent rows of said chain stitches and with the strands being positioned with major portions of adjacent strands in side by side partially overlapping relationship and covering more than 50 percent of the area between the spaced rows of chain stitches.

2. A warp knit pile fabric according to claim 1 wherein said group of warp yarns also are in the form of ribbon-like strands of plastic film material.

3. A warp knit pile fabric according to claim 1 wherein said ribbon-like strands are of polypropylene plastic material.

4. A warp knit pile fabric according to claim 1 wherein said ribbon-like strands are of polyester plastic material.