IMPROVED LACES FOR USE WITH FOOTWEAR, SPORTS EQUIPMENT AND THE LIKE
Laces for footwear or sporting equipment comprised of yarns made from liquid crystal polymer (LCP) fibers. The laces may comprise 100% liquid crystal polymer, or may comprise between about 30% to 99% liquid crystal polymer fibers and a portion of other fibers. The laces may be solid braid construction.
The present invention relates to improved laces for use with footwear, sports equipment and the like.
BACKGROUND OF THE INVENTIONLaces for footwear, such as shoes and boots, and for sports equipment, such as skates, rollerblades, boxing gloves and sports padding, are typically made from conventional fibers—cotton, nylon or polyester. One problem with these prior art laces is that they wear out as a result of abrasion and break frequently, usually at inopportune moments and thus render the associated footwear or sports equipment inoperable. Laces made of aramid fiber, such as that sold under the trademark KEVLAR by DuPont, have recently been made available, but testing and experience has shown that these do not last even as long as those made of the traditional materials. Accordingly, it is desirable to use laces that are significantly stronger and resistant to wear and are less prone to breakage than the laces of the prior art.
SUMMARY OF THE INVENTIONThe above shortcomings may be addressed by providing, in accordance with the invention, laces for footwear or sporting equipment comprised of yarns made from liquid crystal polymer (LCP) fibers.
In another aspect, the present invention provides for the use LCP fiber in laces for footwear or sports equipment. In another aspect, the present invention provides methods of securing an item of footwear or sports equipment having eyelets therein for that purpose, the methods comprising providing laces comprised of LCP fiber, and threading the laces through the eyelets in a configuration that enables said item to be secured. In yet another aspect, the present invention provides methods of manufacturing laces for footwear, sporting equipment and the like, comprising providing yarns comprised of liquid crystal polymer (LCP) fibers and weaving said yarns into a braid suitable for use in laces.
In preferred embodiments of the present invention, the laces comprise of 100% high-modulus multifilament yarn that is made from melt-spun liquid crystal polymer (LCP), also known as aromatic polyester, such as that sold under the trademark VECTRAN.
In alternative embodiments, of the present invention, the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers. For example, in such alternate embodiments, the amount of LCP fibers in the laces by percentage of total fibers may be in an amount from a minimum of 30%, 40%, 50%, 60%, or 70% to a maximum of 50%, 60%, 70%, 80%, 90% or 99%, wherein a range may, for example, be selected from any of the foregoing minimum values in combination with any of the foregoing maximum values, or any value lesser than, greater than or in between, for example, 30% to 99%, 60% to 99% or 80% to 99%.
LCP fiber is a high-modulus fiber, meaning that it is stiffer in tension and does not stretch as much as conventional fibers. It was determined that LCP fiber is very resistant to abrasion, more than most conventional fibers. LCP fiber is also much stronger than the conventional fibers. As well, the greater tensile stiffness and strength of LCP fiber allows pulling the laces tighter. This is especially advantageous in sporting equipment where generally greater force is required to pull the parts of the equipment together.
The increased strength and reduced abrasion of laces made from LCP fiber result in fewer breaks, increased reliability and longer lifetime of the footwear or sporting equipment.
The greater tensile stiffness of laces made from LCP fiber means that these laces will stretch less as a person walks, runs, skates, etc. with the associated footwear or sports equipment. Repeated stretching and relaxing of conventional laces causes the laces to move through the eyelets in the footwear or equipment and abrade against the eyelets as well as against other parts of the footwear or equipment, or against the laces themselves. This abrasion leads to deterioration and breakage of the laces. It was determined that the laces made from LCP fiber do not stretch as much and thus are subjected to less abrasion and will last longer than the prior art laces.
The greater tensile stiffness of laces made from LCP fiber also means that after the LCP fiber laces are tied at a desired tightness, they will remain tied at that tightness. In contrast, conventional fiber laces stretch and loosen, and thus require frequent retightening.
These and other aspects, features and embodiments are set forth within this application. The present invention comprises a variety of aspects, features and embodiments; such multiple aspects, features and embodiments can be combined and permuted in any desired manner.
DETAILED DESCRIPTIONThe present invention provides laces for footwear or sporting equipment comprised of liquid crystal polymer (LCP) fibers. LCP fibers have much higher tension stiffness than conventional fibers used in laces. They are also significantly stronger than conventional fibers. An example of liquid crystal polymer (LCP), also known as aromatic polyester, is the product produced and sold under the trademark VECTRAN by Kuraray America.
It was surprisingly discovered in laboratory performance tests on laces made of LCP fiber and on commercially available laces made of polyester and aramid fibers (KEVLAR), that the LCP fiber laces lasted at least five times longer than the best polyester fiber laces, and about twenty times longer than the best aramid fiber laces.
The LCP fiber laces in the tests were solid braid construction. In solid braid construction, all of the strand carriers on the braider move in the same direction. A strand moves under another, moves to the side in the interior of the rope, comes back to the surface, and goes under again. All of the strands on the surface appear aligned with the axis. Below the surface, the strands cross over to one side, always in the same direction.
In these tests, the laces were cycled back and forth through metal eyelets, similar to those used in boots, shoes, and sporting equipment, with an applied load of 2 lb (i.e. 907 g) weight until the laces failed. The average cycles to failure for the LCP fiber laces was 201,989 cycles, and these LCP laces significantly outperformed the polyester and aramid fiber laces.
The average cycles to failure for the best brand of polyester fiber laces was 37,802 cycles. Other brands of polyester fiber laces performed only to averages of 10,593 cycles and 8,432 cycles. The best brand of all-aramid fiber laces survived an average of 9,518 cycles. Another brand of all-aramid fiber laces survived to an average of only 4,466 cycles. Another brand had only several strands of aramid mixed with polyester fiber, and it survived 6,775 cycles. Yet another brand which was called aramid but actually had no aramid fiber and was made entirely of polyester fibers, survived an average of 7,380 cycles.
Table 1 summarizes information on the sources and characteristics of the tested boot laces.
The construction of the shoe laces varied. Several, including the LCP fiber laces, were solid braid. Several were hollow braid sheath, with or without core. Several were flat braid. The PROCARE KEVLAR lace comprised a polyester hollow-braid sheath and a solid-braid multi-color polyester core. There was actually no KEVLAR yarn in this product. The gold KEVLAR was a flat-braid construction of KEVLAR strands. The black and gold KEVLAR was a flat-braid construction comprised of two gold KEVLAR strands and many black polyester strands.
The tests were conducted on a modification of the 4-station yarn-on-yarn abrasion test machine. That test machine is usually used to conduct yarn-on-yarn abrasion tests in accordance with industry standards. The modified test machine was provided with ¼ inch (6.35 mm) brass grommets, similar to those used in boots, inserted in holes drilled through aluminum angle bars. These bars were mounted on the four stations of the test machine. Each of the lace specimens was run through the brass grommet, and each lace specimen was pulled back and forth through the grommet under an applied load of 2 lb (907 g) with a stroke of 2 inches (50.8 mm) and at a rate of one cycle per second. Cycles for each specimen were counted by counters that shut off automatically when the lace failed or when it became so damaged that it would be unusable.
With reference to the figures,
These performance tests demonstrated that, surprisingly, the LCP fiber laces have a service life that is at least five times longer than the best polyester fiber laces and about twenty times longer than the best aramid fiber laces.
In these tests, the principal cause of wear and failure of the laces was determined to be internal abrasion resulting from fibers rubbing against each other when the lace flexed as it moved around the radius of the metal eyelet. Both polyester and LCP fiber yarns are very resistant to this type of internal wear. Aramid is much less resistant to this type of wear.
Each of the laces in these tests were subjected to the same 2 inch (50.8 mm) stroke around the radius of the metal eyelet. It was discovered that because LCP fiber laces exhibit virtually no stretch when compared to polyester and other conventional fiber laces, they would not move as much around the radius of the metal grommet, and they would suffer even less internal abrasion. Thus, when used in footware and sports equipment, the service life performance of the LCP fiber laces is expected to be even better relative to the polyester fiber laces than the five-times ratio demonstrated in these tests.
In the preferred embodiments of this invention, the laces are comprised 100% high-performance multifilament yarn that is melt spun from liquid crystal polymer (LCP), also known as aromatic polyester, such as that sold under the trademark VECTRAN.
In other embodiments of the present invention, the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers. For example, in such alternate embodiments, the amount of LCP fibers in the laces by percentage of total fibers may be in an amount from a minimum of 30%, 40%, 50%, 60%, or 70% to a maximum of 50%, 60%, 70%, 80%, 90% or 99%, wherein a range may, for example, be selected from any of the foregoing minimum values in combination with any of the foregoing maximum values, or any value lesser than, greater than or in between, for example, 30% to 99%, 60% to 99% or 80% to 99%.
Claims
1. Laces for footwear, sporting equipment and the like, the laces comprising high modulus fibers selected from the group consisting of liquid crystal polymer (LCP).
2. The laces as in claim 1 wherein the laces are comprised of 100% liquid crystal polymer (LCP).
3. The laces as in claim 1 wherein the laces are comprised of 100% high-performance multifilament yarn that is melt spun from liquid crystal polymer, such as that sold under the trademark VECTRAN.
4. The laces as in claim 2 wherein the laces are solid braid construction.
5. The laces as in claim 3 wherein the laces are solid braid construction.
6. The laces as in claim 1 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 30% to 99%.
7. The laces as in claim 1 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 60% to 99%.
8. The laces as in claim 1 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 80% to 99%.
9. (canceled)
10. A method of securing an item of footwear or sports equipment having eyelets therein for that purpose, the method comprising providing laces comprised of LCP fiber, and threading said laces through the eyelets in a configuration that enables said item to be secured.
11. The method of claim 10 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 30% to 99%.
12. The method of claim 10 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 60% to 99%.
13. The method of claim 10 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 80% to 99%.
14. A method of manufacturing laces for footwear, sporting equipment and the like, comprising providing yarns comprised of liquid crystal polymer (LCP) fibers and weaving said yarns into a braid suitable for use in laces.
15. The method of claim 14 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 30% to 99%.
16. The method of claim 14 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 60% to 99%.
17. The method of claim 14 wherein the laces comprise partially of liquid crystal polymer (LCP) fibers and partially of other fibers, and wherein the amount of LCP fibers in the laces by percentage of total fibers is between about 80% to 99%.
Type: Application
Filed: Sep 21, 2009
Publication Date: Oct 6, 2011
Inventor: Paul Abell (Langley)
Application Number: 13/119,943
International Classification: A43C 9/00 (20060101); A43C 5/00 (20060101); D04C 1/00 (20060101);
