Sewing – Method of sewing – Stitch forming
Reexamination Certificate
2004-02-11
2004-08-31
Nerbun, Peter (Department: 3765)
Sewing
Method of sewing
Stitch forming
C112S080230
Reexamination Certificate
active
06782838
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to a system and a method adapted to control bow or skew within a web of material to be processed. More particularly, the invention relates to a system and a method used to control any bow and/or skew that may be present within a backing material passed toward the needle bar of a tufting machine.
BACKGROUND OF THE INVENTION
As known, during the manufacture of carpet or other tufted work products, a primary backing material is supplied from a storage roll and continuously fed in a warp, i.e., a longitudinal or lengthwise, direction through a tufting machine. The tufting machine is provided with a reciprocating needle bar having a series of spaced tufting needles disposed thereon. The tufting needles are each threaded with the yarn to be tufted in the backing material, the needles being passed together through the backing material by the reciprocating motion of the needle bar as the backing material is moved or carried past the needle bar during machine operation to form tufts in the “face” of the backing material.
The backing material may comprise a woven, a non-woven, a knitted, or a needle punched fabric, as well a stitch bonded primary backing material. The backing material therefore comprises a plurality of yarns, fibers, or filaments extending both longitudinally in the warp direction and perpendicularly in a weft direction across the width of the backing material. As one skilled in the art appreciates, materials such as polypropylene, as well as polyesters, hemp, composites, blend, nylons, or cottons, can be used to form the backing material.
A problem that exists in the art, however, is that the backing material made within industry tolerances is often distorted, with the result that oftentimes the weft lines within the backing material will not be aligned with the needle bar of the tufting machine as the backing material is advanced toward the needle bar. Four specific alignment problems result from the backing material being misaligned with the needle bar of the tufting machine. These problems being a “bow,” or a “skew” in the weft-oriented tufts tufted in the backing material, or the tufted yarns being “hooked,” and/or extending along a wiggled weft line.
Bow exists within a tufted product when the weft yarns, fibers, or filaments in the backing material are not linear or straight, e.g., there is a curvature in the weft yarns relative to the needle bar. Skew, in comparison, exists when the-weft yarns are not parallel to the needle bar, for example the weft yarns may extend along a straight line, but the line otherwise forms an angle relative to the needle bar. Hook exists when the weft yarns are oriented in a curved, or extend along a non-parallel, line or lines relative to the needle bar along at least a portion of their length, and appears at the edge(s) of the backing material. Wiggle exists when the weft yarns change from any combination of a positive to a negative angle relative to the needle bar in a specific section of the backing material.
Accordingly, when the problems of bow and/or skew occur within the tufts formed in the backing material, the tufted yarns are not parallel to at least a portion of the length of the weft line in the backing material. Thus, when attempting to join two adjacent carpet sections together along their respective weft lines, for example in a large space such as a public concourse or a ballroom, a noticeable difference can be seen in the tufted and/or printed carpet patterns from section to section of the carpet, which results in an undesirable or unsightly appearance in the installed carpet.
Examples of known devices and systems which attempt to address the problems of bow and skew in tufted products are found in U.S. Pat. No. 4,255,050 to Beckstein et al., U.S. Pat. No. 4,261,498 to Short, U.S. Pat. No. 4,364,502 to Fentress, and U.S. Pat. No. 5,035,030 to Pellari. Additional patents which may be relevant to this problem are U.S. Pat. No. 4,656,360 to Maddox et al., U.S. Pat. No. 4,987,663 to Epple, and U.S. Pat. No. 5,416,593 to Vercruysse.
What is needed, therefore, but seemingly unavailable among the known devices, is an improved system and a method for controlling, i.e., for reducing or eliminating to the greatest extent possible, the bow and skew of a backing material fed through a tufting machine.
SUMMARY OF THE INVENTION
The present invention overcomes some of the design deficiencies of the known art by providing an improved system and a method for controlling the presence of any bow and/or skew within a backing material to be fed through a tufting machine. This is accomplished by providing such a system and method in association for use with a conventional tufting machine having a reciprocating needle bar disposed with respect to a tufting zone through which the backing material is fed, a cloth feed roll positioned upstream of the tufting zone for moving the backing material toward the tufting zone, and a roll of backing material from which the backing material is supplied. The backing material may be of woven or of non-woven construction, and will be comprised of a plurality of elongate warp yarns, fibers, or filaments extending longitudinally in the lengthwise direction of the backing material, and a plurality of weft yarns, fibers, or filaments extending substantially perpendicular to the warp yarns and in the cross-length direction of the backing material. The terms yarn, fiber, and filament are used interchangeably herein, and refer to the aforementioned warp and weft yarns, fibers, or filaments within a woven or a non-woven backing material, respectively.
In a first embodiment, the method of the invention includes aligning at least one elongate weft yarn marker disposed on the backing material with the needle bar so that the at least one weft yarn marker is parallel to the needle bar. The at least one weft yarn marker is disposed on or within the backing such that it is parallel to the weft yarns of the backing material. This method may also include the aspect of detecting whether the at least one weft yarn marker is parallel to the needle bar as the backing material is passed toward the tufting zone.
The method may also include detecting a plurality of closely spaced and substantially parallel weft yarn markers formed as a group of weft yarn markers on the backing material, and of detecting a series of weft yarn marker groups spaced in the lengthwise direction of the backing material. In an alternate embodiment, the method comprises detecting the at least one weft yarn marker as the backing material is being passed toward the tufting zone, and aligning the at least one weft yarn marker with the needle bar so that the at least one weft yarn marker is parallel to the needle bar. This may be done with an automated detection device, or by manually observing the at least one weft yarn marker with respect to the needle bar of the tufting machine.
Yet another embodiment of the method therefore comprises physically observing, i.e., manually or visually detecting, the at least one weft yarn marker with respect to the needle bar as the backing material is passed toward the tufting zone, and aligning, either automatically or manually, the at least one weft yarn marker with the needle bar so that the at least one weft yarn marker is substantially parallel to the needle bar.
The method further comprises positioning a bow roll intermediate the roll of backing material and the cloth feed roll and used to selectively increase and decrease the tension of at least a portion of the backing material; and alternately, to increase and decrease the tension of a central portion of the backing material in response to the detection of the at least one weft yarn not being substantially parallel to the needle bar in order to control any bow that may be present in the weft yarns of the backing material with respect thereto.
The method also comprises mounting the roll of backing material on at least one jack assembly, or on a pair of spaced jack assemblies positioned at the ends of
Segars Jeffrey W.
Vaughan William N.
Columbia Insurance Company
Needle & Rosenberg, PC.
Nerbun Peter
LandOfFree
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