Textiles: cloth finishing – Shrinking – Thread compacting
Reexamination Certificate
2000-10-20
2004-01-27
Vanatta, Amy B. (Department: 3765)
Textiles: cloth finishing
Shrinking
Thread compacting
C028S142000
Reexamination Certificate
active
06681461
ABSTRACT:
BACKGROUND OF THE INVENTION
DISCUSSION
The knitting industry uses, for manufacture of garments, various compacted knitted textile fabrics of different constructions generally accepted as having been shrink-proofed. For such compressive shrink-proofing, two-pass types of compactors have been in vogue, as disclosed in each of U.S. Pat. Nos. 4,689,862 and 5,655,275; which compactors are typical of machines used for knitted fabric made of natural and/or man-made fibers. Although these compactors produce generally acceptable shrink-proofing results, they are temperamental and require frequent re-adjusting of their compression zones.
U.S. Pat. No. 5,016,329 uses two stationary opposing blades to form a compression zone. A fabric being compacted is required to change direction abruptly on entering and exiting a compression zone. Applicant's GULL-WING brand compactor, disclosed in U.S. Pat. No. 5,012,562, employs a compression zone consisting of an apex (or nadir) of a stationary notched shoe and an opposing impact blade with the fabric being compacted required to make a “V” turn in passing through a compression zone. Common to the prior art compactors presently used for shrink-proofing knitted textile fabrics is a requirement for an abrupt change of direction of fabrics due to an organized obstruction in their respective compression zones. The abrupt change of direction contributes to jamming, for example, at the apex of the GULL-WING brand compactor. A single-pass in-line compression zone introduced in Applicant's present invention eliminates the abrupt change of direction to render the compactor of the present invention more operator-friendly, knit-friendly and produces trouble-free superior shrink-proofing on a wide variety of constructions of knitted textile fabrics and other fabrics having characteristics kindred to knitted textile fabrics.
THEORY
Compressive shrink-proofing of knitted textile fabrics, formed from interlocked loops of yarns made usually of natural fibers or man-made fibers had its origin in shrink-proofing of woven textile fabric webs. With increased popularity of knitted garments, compressive shrink-proofing of knitted textile fabrics evolved from prior experience obtained by working with flat woven textile fabric webs. Woven textile fabrics webs are rectilinear grids of threads having longitudinal warp threads interwoven by transverse fill threads. Emphasis in compaction for shrink-proofing of woven textile fabric webs naturally focused on a need for longitudinal compression. The woven textile fabrics were and are manufactured in such continuous webs which inevitably get stretched lengthwise while being woven, transported and processed. So it was and is logical, convenient and effective to shrink compressively the woven fabric webs in a longitudinal direction along their continuous webs. However, knitted textile fabrics, like randomly deposited fabrics made of natural or man-made fibers, are neither formed nor structured similarly to woven textile fabrics.
Knitted textile fabrics, for example, are composed of yarns, usually of natural fibers, formed in interlocking curvilinear loops which are arranged in stitch rows sometimes aligned perpendicularly to and sometimes skewed from perpendicular orientations relative to alignment of their continuous webs. The loops generally interlock with each other substantially at right angles (orthogonally) to their respective stitch rows. It is sometimes convenient to visualize stitch rows ideally as being straight and aligned transversely relative to a longitudinal path of the fabric, like soldiers marching on parade through their compactor. Yet such an ideal image of stitch rows through a compactor rarely finds its counterpart in the real world. Knitted textile fabrics frequently are not designed with straight transverse stitch rows. Handling and treatment of knitted textile fabrics, warp, bend, twist and otherwise distort their stitch rows. Further, the stitch rows themselves are formed as a progression of repeating series of curvilinear loops of yarn. So as far as compacting of knitted textile fabrics is concerned, terms such as “straight” or “aligned” stitch rows are wishful euphemisms.
A loop of yarn in a knitted fabric actually exhibits behavior characteristics quite different from those that logically might be expected from an ideal image of stitch rows. Applicant examined behavioral characteristics of actual knitted structures as they undergo compaction, so as to deal with on their own terms with the loops and stitch rows as they actually exist in the real world.
The knitted textile fabrics, when composed of natural fibers, typically are manufactured in the form of continuous tubes which are then flattened and compacted in a longitudinal direction analogous to compacting of woven textile fabrics. Alternately the knitted tubes may be split open, spread and subjected to longitudinal compacting as open webs. Knitted textile fabrics, with small loops or fine yarns making up the loops, require compaction as open webs. As has been noted herein, technology which evolved from compacting of woven textile fabric webs generally has achieved inconsistent success in treating knitted textile fabrics. Lack of consistent success has been common to compaction of knitted textile fabrics both as tubes and as open webs. Accordingly some people look upon compressive shrinking of knitted fabrics as an occult art.
In actual knitted textile fabrics we frequently can expect unreliable orientation (skewing) of stitch rows formed of interlocked yarn loops. An alignment of the loops has been recognized by Applicant to occur orthogonally each individual loop relative to its related skewed stitch row. Applicant's recognition, acceptance and accommodation of the skewed orientation of the stitch rows and inherent behavior of the loops relative to their respective stitch rows are at a crux of Applicant's successful, consistent and reliable compacting of knitted textile fabrics and other similar fabrics made of natural and/or man-made fibers. It followed that organizing apparatus and a related method for freeing the interlocked loops of yarn to move easily, as they naturally choose, toward each other orthogonally relative to their skewed stitch rows opened the door to Applicant's success.
Effective compressive shrink-proofing of knitted textile fabrics of natural fibers depends in part on expansion of heated and/or moistened yarn caused by partial unraveling of their fibers. Steam puffing and lubricating effects on nautral yarn loops of knitted textile fabrics are discussed in Applicant's U.S. Pat. No. 4,447,938 whose disclosure is included herein by reference. Another reality of compaction is that the fabric reduces in volume by mechanical pushing of the interlocked loops of yarn preferably toward each other. The present invention focuses on the mechanical pushing action.
The loops interlock generally at right angles (orthogonally) each relative to its related stitch row. With the stitch rows unreliably organized, and the yarn loops arranged orthogonally thereto, application of longitudinal compaction through a crimped, bent, kinked or otherwise obstructed compression zone was effective along a series of longitudinal vectors from a continuum of points along a curvilinear loop of yarn. Simultaneously, a series of companion transverse vectors of any or all of the same points could thereby be either wasted or they could contribute to counterproductive stretching. Accordingly a substantial portion of longitudinal compacting effort on knitted textile fabrics was self-defeating when performed through the crimped, bent, kinked or otherwise obstructed compression zones of the prior art. By eliminating abrupt direction change, due to obstruction, as the web of knitted fabric passes through the compression zone, Applicant frees the loops each to move according to its own natural preference, which he recognized to be orthogonally relative to its related stitch row, unaffected by likely skewed orientations of the stitch rows that
Baxley Charles E.
Vanatta Amy B.
LandOfFree
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