Textiles: knitting – Fabrics or articles – Warp
Reexamination Certificate
1998-08-14
2001-05-22
Worrell, Danny (Department: 3741)
Textiles: knitting
Fabrics or articles
Warp
Reexamination Certificate
active
06233978
ABSTRACT:
BACKGROUND OF INVENTION
The prison population in the U.S. is now approaching the 2 million mark. With growing prison overcrowding and resultant inmate tensions, the guards and correctional officers are increasingly exposed to stab attacks by violent criminals using a variety of home made thrusting weapons such as shanks, ice picks, knives, sharpened nails or other objects. As these attacks can inflict life-threatening wounds, many guards are now wearing protective suits designed to stop penetration of such weapons. The suits are made with multiple woven fabric layers using high performance, high tenacity yarns.
A typical fabric used is woven with one of the above yarns in a density of 70 picks×70 warp ends/inch. The fabric is coated with a special resin to resist and retard penetration of an ice pick point by preventing the weave components from shifting. About 27 layers or plies of fabric are combined to provide a protective, stab resistant shield placed inside the suit. The suits are tested using the current standard, which stipulates resistance to an impact valve of 81.1 foot-pounds using a 7 inch long pick in a diameter of 0.0163 inch with a 15:1 taper and steel hardness of 42 c, as per the State of California body armor specifications.
Circular weft knit fabrics have also been introduced into this field. They are made on interlock or double knit machines. These fabrics rely on heavy resin impregnation to stabilize or “freeze” the loop components in order to enhance resistance to penetration by a pick or other weapon.
One of the main disadvantages of woven fabrics in offering protection from thrust or stab weapons is the relative ease with which the weft and warp threads slide on each other as the weapon's point impinges on them, pushing them aside, and leading to effective penetration. All woven structures are held together by friction existing between its components and have to use various resins to immobilize them and preserve the fabric integrity as it is impacted by a thrusting point. This makes the fabric heavy, stiff and almost impenetrable to air, leading to wearer discomfort.
Circular knit fabrics, while more permeable to air than woven ones, are inherently unstable due to their residual elasticity, which must be eliminated with the application of a heavy resin coating. Furthermore, circular knit fabrics cannot be made very tight in order to produce a high thread density per unit area. This is because of their rather open loop structure.
For fabrics to be truly effective in resisting point penetrations, it is essential to have a high density of yarn crossings, firmly anchored in the matrix of its structure, and without relying on friction or resin impregnation. Warp knit fabrics satisfy these requirements better than wovens or circular knits.
SUMMARY OF THE INVENTION
A warp knit fabric for resisting point penetration of thrusting type weapons is provided. The fabric comprises a multiplicity of thread systems made from high performance yarns with a minimum tenacity of 7 gram/denier. Each of the thread systems are produced by bar guide movement having the formulation of: 1−0
−(n+1), wherein n is the spaces traversed by the guide bar.
In one embodiment, a multi-axial warp knit fabric is produced. One thread system comprises vertical warp inlays, while a second comprises horizontal weft inlays. Preferably, a series of diagonal inlay systems are also provided. Significantly, each thread system is disposed one on the other. A loop structure is provided for holding the thread systems together.
The advantages of using warp knits as a point penetration protective medium are as follows:
1) ability to engineer structures with a much higher thread density than possible with either wovens or circular knits.
2) positively locked or anchored structure members, not relying on friction or resin impregnation to preserve its integrity when impacted by a point.
3) facility to use multiple guide bars to produce very dense combination fabrics. Any warp knit structure is the result of two or more sub-structures generated by each guide bar and interknitted with each other as to render a compact, dense product.
4) the thread density may further be enhanced by a technique known as warp and weft insertion where straight lengths of threads are introduced into the structure in the horizontal and vertical directions.
5) warp knit fabrics, because of their system of loops, have a natural air permeability, superior to wovens, which have to be tightly constructed to prevent slippage of their components. The permeability of warp knits enables them to transmit perspiration vapor through the fabric and thus enhance wearing comfort.
6) warp knit fabrics are more pliable and flexible than wovens and tend to conform to the contours of the wearer's body.
Other advantages will be obvious or apparent from the following description.
REFERENCES:
patent: 4004295 (1977-01-01), Byrnes, Sr.
patent: 4518640 (1985-05-01), Wilkens
patent: 5415007 (1995-05-01), Eng
patent: 5822791 (1998-10-01), Baris
patent: 5858054 (1999-01-01), Rosen
patent: 5887453 (1999-03-01), Woods
Gehring, Jr. George G.
Reisfeld Aaron
Gehring Textiles, Inc.
Gottlieb Rackman & Reisman P.C.
Worrell Danny
LandOfFree
Pointed thrust weapons protective fabric system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pointed thrust weapons protective fabric system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pointed thrust weapons protective fabric system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2454182