cut resistant yarns suitable for knitting gloves and sleeves and methods of making the yarns are disclosed. The yarns are made up of a bundle of continuous filaments formed of a synthetic material, e.g., polyethylene, polypropylene, nylon or polyolefin, and a stretchable yarn, e.g., Spandex® or Lycra®. The yarns are made in such a manner that when completed the continuous filaments are substantially parallel to one another and to the longitudinal axis of the yarn so that items made from them will not twist or curl up, yet will provide good resistance to cutting.
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0. 17. A glove woven from a cut resistant, stretchable yarn, said yarn having a longitudinal axis, said yarn comprising:
a stretchable second yarn and a bundle of continuous filaments formed of a synthetic material, said stretchable second yarn being of substantially smaller denier than the bundle of filaments;
each of said continuous filaments of the bundle of continuous filaments having a longitudinal axis, said bundle being in a twisted condition wherein the bundle of filaments has a torque in a first rotational direction,
said bundle of continuous filaments being helically wound about the stretchable second yarn wherein said bundle of filaments has a torque in a second rotational direction establishing a force in said second rotational direction, said torque in said second rotational direction substantially canceling said torque in said first rotational direction,
whereupon said bundle of filaments assumes a condition wherein all of said filaments of said bundle have a substantially zero torque and are substantially parallel to one another and the stretchable second yarn twists about its longitudinal axis and moves to a position wherein it is helically disposed around the bundle of filaments.
0. 9. A cut resistant, stretchable yarn, said yarn having a longitudinal axis, said yarn comprising:
a stretchable second yarn and a bundle of continuous filaments formed of a synthetic material, said stretchable second yarn being of substantially smaller denier than the bundle of filaments;
each of said continuous filaments of the bundle of continuous filaments having a longitudinal axis, said bundle being in a twisted condition wherein the bundle of filaments has a torque in a first rotational direction;
said bundle of continuous filaments being helically wound about the stretchable second yarn wherein said bundle of filaments has a torque in a second rotational direction establishing a force in said second rotational direction in said bundle of filaments, said torque in said second rotational direction substantially canceling said torque in said first rotational direction,
whereupon said bundle of filaments assumes a condition wherein all of said filaments of said bundle have a substantially zero torque and are substantially parallel to one another and the stretchable second yarn twists about the longitudinal axis of the yarn and moves to a position wherein it is helically disposed around the bundle of filaments.
1. A cut resistant, stretchable yarn suitable for knitting gloves and sleeves, said yarn having a longitudinal axis and comprising a stretchable second yarn and a bundle of continuous filaments formed of a synthetic material, said stretchable second yarn being of substantially smaller denier than the bundle of filaments and being initially under tension to cause it to stretch, each of said continuous filaments of the bundle of continuous filaments having a longitudinal axis and, said bundle being in a twisted with respect to one another whereby condition wherein the bundle of filaments have has a torque in a first rotational direction applied to them, said bundle of continuous filaments being helically wound about the stretched stretchable second yarn to apply wherein said bundle of filaments has a torque in a second rotational direction to said filaments to cause them to untwist with respect to one another establishing a force in said second rotational direction, said torque in said second rotational direction substantially cancelling said torque in said first rotational direction, whereupon said bundle of filaments again assumes the a condition wherein all of said filaments of said bundle have a substantially zero torque and are substantially parallel to one another and to the longitudinal axis of the yam yarn and the stretchable yam second yarn twists about its the longitudinal axis of the yarn and moves to a position wherein it is helically disposed around the parallel bundle of filaments of said bundle.
0. 14. A method for making a cut resistant yarn suitable for knitting gloves and sleeves, said yarn having a longitudinal axis, said method comprising:
(A) providing a stretchable second yarn and a bundle of continuous filaments, each formed of a synthetic material, each of said continuous filaments of said bundle of continuous filaments having a longitudinal axis;
(B) twisting said bundle of filaments whereby the bundle of continuous filaments has a torque in a first rotational direction applied to it;
(C) tensioning the stretchable second yarn to cause it to stretch;
(D) winding said bundle of continuous filaments about the stretched stretchable second yarn to apply a torque in a second rotational direction to said bundle of continuous filaments to cause it to untwist in said second rotational direction, said torque in said second rotational direction substantially canceling said torque in said first rotational direction, and
(E) releasing said torque in the second rotational direction on said bundle of filaments and releasing said tension on said stretchable second yarn,
whereupon said bundle of continuous filaments assumes a condition wherein all of said filaments of said bundle are substantially parallel to one another and the stretchable yarn twists about its longitudinal axis and moves to a position wherein it is helically disposed around the parallel filaments of said bundle.
6. A method for making a cut resistant yarn suitable for knitting gloves and sleeves, said yarn having a longitudinal axis and, comprising:
(A) providing a stretchable second yarn and a bundle of continuous filaments, each formed of a synthetic material, each of said continuous filaments of said bundle of continuous filaments having a longitudinal axis;
(B) twisting said bundle of filaments with respect to one another whereby the bundle of filaments have has a torque in a first rotational direction applied to them it;
(C) tensioning the stretchable second yarn to cause it to stretch;
(D) winding said bundle of continuous filaments about the stretched stretchable second yarn to apply a torque in a second rotational direction to said bundle of continuous filaments to cause them it to untwist with respect to one another in said second rotational direction, said torque in said second rotational direction substantially cancelling said torque in said first rotational direction; and releasing said torque in the second rotational direction on said bundle of filaments and releasing said tension on said stretchable second yarn, whereupon said bundle of continuous filaments again assumes the a condition wherein all of said filaments of said bundle are substantially parallel to one another and to the longitudinal axis of the yarn and the stretchable second yarn twists about its longitudinal axis and moves to a position wherein it is helically disposed around the parallel filaments of said bundle.
2. The yarn of
3. The yarn of
4. The yarn of
5. The yarn of
7. The method of
8. The method of
0. 10. The yarn of claim 9 wherein said continuous filaments are formed from a material selected from the group comprising polyethylene, polypropylene, nylon and polyolefin.
0. 11. The yarn of claim 9 wherein said stretchable second yarn is formed from a material selected from the group comprising spandex and Lycra®.
0. 12. The yarn of claim 9 wherein said yarn comprises at least a portion of a glove or sleeve knitted from said yarn.
0. 13. The yarn of claim 9 wherein said bundle of filaments has a denier in the range of approximately 100 to approximately 1200 and wherein said stretchable second yarn has a denier in the range of approximately 40 to approximately 70.
0. 15. The method of claim 14 wherein said step including providing the bundle of continuous filaments includes providing a bundle of filaments formed from a material selected from the group comprising polyethylene, polypropylene, nylon and polyolefin.
0. 16. The method of claim 14 wherein said stretchable second yarn is formed from a material selected from the group comprising spandex and Lycra®.
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This application claims priority from provisional U.S. Patent Application No. 60/653,010, filed on Feb. 15, 2005.
“Not Applicable”
“Not Applicable”
1. Field of Invention
This invention relates generally to cut resistant yarns and more particularly to cut resistant yarn for gloves or sleeves.
2. Description of Related Art
Knitted “work” gloves formed of conventional materials, such as cotton or poly-cotton provide some measure of protection from injury and some cushioning for the hand of workers, but are notoriously deficient insofar as providing resistance to cutting. Thus, it is a common practice to knit work gloves of cut resistant yarns. Most cut resistant yarns are formed of filaments—i.e., they are a bundle of continuous filaments or fibers. The term filaments and fibers are used interchangeably herein, and may be given the same general meaning, e.g., microscopically, looking like a bundle of fishing lines.
Cut resistance is obtained by several factors. One factor can be deemed to be the tendency to produce “slippage.” In particular, when a blade or other sharp instrument passes over the yarn, it slides along the smooth surfaces of the fiber bundle, rather than catching on the yarn, which action would result in a tendency to cut the yarn. Tensile strength is another factor in establishing cut resistance. In this regard, the shear strength of the fiber is selected to be so strong that it prevents the fiber from breaking. The abrasive action of the fiber is also a factor, since the harder the fiber, the greater the tendency to dull the cutting edge, thereby reducing the tendency of the fiber to be cut. Another significant factor is what may be called “rolling.” This is the ability of the fibers of the yarn to twist or roll about their longitudinal axis as the blade moves across the yarn. Such rolling action enhances cut resistance by denying the cutting edge a stationary surface to cut.
Filament yarns, due to their structure, will not stretch. Stretchability is of considerable importance in order to readily knit a viable, low-cost glove. Consequently, the knitted glove industry, typically plies these yarns with an elastic or stretchable yarn such as Spandex® or Lycra® alongside the filament yarn and then wraps the stretchable yarn under tension in a helical pattern around the filament yarn, with the helix spacing of several twists of stretchable yarn per inch of the filament yarn (i.e., the fiber bundle). When the tension is relaxed, the resulting combined yarn is a stretchable filament yarn that can be knit into gloves or sleeves.
Unfortunately, the plying process forces the filament yarn to twist in the same direction as the stretchable yarn is plied (wound). When this happens two things occur. First, the ability of each fiber of the bundle to roll individually is restricted, thus reducing cut resistance of the combined yarn. Second, the combined yarn then develops a twist to it.
When gloves and arm sleeves are knitted, any yarn that is twisted, such as the combined yarn just described, will cause a torque. When this happens, glove fingers become twisted and arm sleeves begin to wrap around the arm, which can reduce cut resistance because it is now restricting the ability of the sleeve to stretch. The industry calls this torque in the yarn an “S.” To counteract S torque, it is a common practice in the industry to add another yarn twisted in the opposite direction as the stretchable yarn. This additional yarn is frequently referred to as the “Z” or “zed” yarn. The use of a Z yarn in the combined yarn allows the fingers of a glove knitted from the combined yarn to be flat and a sleeve knitted of it to relax. The Z yarn can be of lesser denier than the stretchable yarn and can be wrapped around the stretchable yarn in the opposite direction to counteract the twist. Alternatively, the Z yarn can be of the same denier as the stretchable yarn and can be run parallel to it and the two combined yarns knitted together so that the twist provided by both yarns counteract each other.
While the use of a Z yarn has the foregoing advantage, it is not without cost. In this regard the use of the additional reverse twisted Z yarn increases the cost of the resulting yarn due to the cost of the Z yarn itself. Moreover, if the Z yarn is counter-wrapped about the stretchable yarn, there is the additional manufacturing costs inherent in effecting that wrapping action. If the Z yarn is run parallel to the stretchable yarn and then the two are knitted together, the resulting glove or sleeve will be considerably thicker (which may be undesirable from the standpoint of flexibility). To keep costs down, it is a common practice to use low cost materials for the Z yarn. Unfortunately, such low cost materials are inferior in that they are not cut resistant. When these low cost Z yarns are added to a glove or sleeve, they tend to break down or cut more easily. When this happens the knitted product falls apart.
Thus, while the above yarns may be generally suitable for their intended purposes, they leave something to be desired from one or more of the following factors, ease of manufacture, effectiveness, reliability and cost.
This invention is directed to cut resistant, stretchable yarns and method of making them. The yarns are suitable for knitting gloves and sleeves. The yarns each have a longitudinal axis. Each yarn comprises a bundle of continuous filaments formed of a synthetic material and a stretchable yarn.
In accordance with one aspect of the invention each of the continuous filaments of the bundle of filaments has a longitudinal axis. The bundle of filaments is twisted in a first rotational direction with respect to the longitudinal axis of the yarn to apply a torque to the bundle in the first rotational direction. The stretchable yarn is wound under tension about the bundle of filaments in a helical pattern in a second and opposite rotational direction with respect to the longitudinal axis of the yarn to apply a torque to the bundle in the second rotational direction. The torque in the first direction substantially cancels the torque in the second direction, whereupon after the stretchable yarn has been made the longitudinal axes of the filaments of the bundle are substantially parallel to one another and to the longitudinal axis of yarn.
In accordance with another aspect of this invention the stretchable yarn is of substantially smaller denier than the bundle of filaments and is initially under tension to cause it to stretch. Each of the continuous filaments of the bundle of filaments has a longitudinal axis and is oriented initially parallel to the other filaments of the bundle. The bundle of filaments is helically wound about the stretched stretchable yarn to apply a torque in a first rotational direction to the filaments of the bundle to cause them to twist with respect to one another in the first rotational direction. The bundle of filaments and the stretchable yarn are thereafter twisted in a second and opposite rotational direction with respect to the longitudinal axis of the yarn to apply a torque to the bundle and to the stretchable yarn in the second rotational direction. The torque in the second direction substantially cancels the torque in the first direction, whereupon the bundle of filaments again assumes the condition wherein all of the filaments of the bundle are parallel to one another and to the longitudinal axis of the yarn and the stretchable yarn twists about its longitudinal axis and moves to a position wherein it is helically disposed around the parallel filaments of the bundle.
In accordance with still another aspect of this invention the continuous filaments of the bundle of filaments are pre-twisted with respect to one another whereby the filaments have a torque in a first rotational direction applied to them. This bundle of pre-twisted filaments is helically wound about the small denier stretchable yarn to apply a torque in a second rotational direction to those filaments to cause them to untwist with respect to one another in the second rotational direction, i.e., the torque in the second direction substantially cancels the torque in the first direction, whereupon the bundle of filaments again assumes the condition wherein all of the filaments of the bundle are parallel to one another and to the longitudinal axis of the yarn, and the stretchable yarn twists about its longitudinal axis and moves to a position wherein it is helically disposed around the parallel filaments of the bundle.
Other aspects of this invention entail methods of producing the cut resistant, stretchable yarns summarized above and of gloves and sleeves formed of such yarns.
The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:
Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown at 20 in
To that end, in
In
As will be appreciated by those skilled in the art, when the stretchable yarn 12 is placed under tension and then wound helically about the periphery of the bundle of filaments 4 it creates a torque on those filaments, whereupon when the resulting yarn is released, the filaments 4 twist and become effectively “locked-up.” In particular, as discussed above this twisting action restrains those filaments so that they are not able to roll individually about their respective longitudinal axes, thereby resulting in a yarn whose cut-resistance is reduced. Moreover, the resulting yarn 10 itself develops a twist to it, whereupon the fingers of gloves or the body of arm sleeves knitted of such a yarn will twist up. As also pointed out above, in order to prevent the tendency of gloves and sleeves knitted of such yarns from curling up, the yarn 10 is commonly wound with a Z yarn in the opposite rotational direction to counteract the torque applied by the stretchable yarn.
The counter-rotation of the filament bundle as the stretchable yarn is being applied (wound about the filaments) applies a torque that is in the opposite direction to the torque applied by the stretchable yarn as it is wound about the bundle. The two torques essentially cancel each other so that end result is that when the yarn 20 is completed and released from the equipment for making it the filaments 4 of the yarn 20 run parallel to one another and can roll individually about their own respective longitudinal axis. This later feature increases the cut resistance, while the former feature ensures that the resulting yarn itself isn't twisted. Accordingly, there is no need to make use of an oppositely wound Z yarn, as has typified prior art stretchable yarns.
Any suitable materials can be used for making the yarn 20. For example, the continuous filaments can be selected from the group comprising polyethylene, polypropylene, nylon and polyolefin. Those materials can have a denier in the range of approximately 100 to approximately 1200. The stretchable yarn can be selected from the group comprising Spandex® and Lycra® and can have a denier in the range of approximately 40 to approximately 70. One particularly suitable yarn for a glove, like that shown in
In
It should be pointed out at this juncture that the direction of twisting of the filaments as described above is merely exemplary. Thus, the filaments 4 of the bundle can be twisted about the stretched fiber 12 in the clockwise direction and then that bundle and the stretched stretchable fiber can be rotated as a unit in the counterclockwise direction by the apparatus 100 to result in a yarn exhibiting the same properties as the yarn 200 described above but whose appearance is slightly different, i.e., the direction of the spiral of the stretchable yarn being opposite to that shown in
In
It should be pointed out at this juncture that the direction of twisting of the filaments as described above is merely exemplary. Thus, the filaments 4 of the bundle can be pre-twisted in the counterclockwise direction R2 and then that twisted bundle can be wrapped about the stretched stretchable fiber 12 in the clockwise direction R1 to result in a yarn exhibiting the same properties as the yarn 300 described above but whose appearance is slightly different, i.e., the direction of the spiral of the stretchable yarn being opposite to that shown in
As should be appreciated by those skilled in the art the yarns of the subject invention are stretchable and cut resistant, yet do not have any substantial residual torque thereon which would tend to cause any item, e.g., a glove, arm sleeve, etc., to be knitted from such yarns to curl or otherwise twist. In accordance with the methods of this invention the formation of each of the yarns is achieved by creating some torque on the yarn which overcomes any other torque existing thereon, so that the continuous filaments of the bundle extend parallel to one another, thereby enabling them to roll somewhat with respect to one another. In particular, in accordance with the first embodiment the bundle of continuous filaments, is counter-twisted, while plying, i.e., helically winding, a stretchable yarn about the filament yarn. The result is a finished yarn whose individual filaments are able to twist and roll individually rather than as a complete yarn. Such action results in significantly improved cut resistance.
The method of making the yarn according to the second exemplary embodiment also results in a yarn that exhibits similar properties to the yarn of the first embodiment insofar as stretchability, resistance to cutting and tendency not to curl or otherwise twist. However, that yarn and its method of production are different. Thus, that method entails tensioning the stretchable yarn 12 to cause it to stretch, winding the bundle of continuous filaments 4 helically about the stretchable yarn to apply a torque in a first rotational direction to said filaments to cause them to twist with respect to one another in the first rotational direction, and twisting the bundle of continuous filaments and the stretchable yarn in a second and opposite rotational direction to apply a torque thereto in the second rotational direction. The torque in the second direction substantially cancels the torque in the first direction, so that when the yarn is released the fibers of the bundle of filaments again assumes the parallel condition, with the stretchable yarn twisted helically around those filaments.
The method of making the yarn according to the third exemplary embodiment also results in a yarn that exhibits similar properties to the yarn of the second embodiment insofar as stretchability, resistance to cutting and tendency not to curl or otherwise twist. However, the method of production of that yarn is slightly different than the method of making the yarn of the second embodiment. In particular, like the method of the second embodiment the stretchable yarn 12 is stretched and the filaments of the bundle of filaments are wound helically around the stretched stretchable yarn. However, unlike that method the filaments 4 of the bundle of filament are pre-twisted in one rotational direction so that when they are wound helically about the stretchable yarn 12 in the second and opposite rotational direction, that action causes them to untwist, i.e., a counter torque is produced offsetting the initial torque placed on those filaments when they are pre-twisted. This results in a yarn, which to all intents and purposes is the same as the yarn of the second embodiment.
As should be appreciated from the foregoing, the yarns of this invention do not require the use of a Z yarn. Thus, gloves, sleeves or another item made of that yarn can be knitted more economically. Moreover, such gloves, sleeves, etc., knitted of those yarns can provide better protection to the wearer, e.g., protection from accidental cutting, with a lighter weight product. This has the obvious advantage of adding to wearing comfort and enabling dexterity. In short the yarns of the subject invention result in knitted products that are more cost effective, have a higher cut resistance and will wear longer than the prior art items.
Without further elaboration the foregoing will so fully illustrate my invention that others, made by applying current or future knowledge, readily adapt the same for use under various conditions of service.
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