WO2005082086A2 - Line having hybrid fibers treated with friction reducing material - Google Patents

Abstract

A treated, multi-fiber line is constructed of at least first and second line strand whch are impregnated or coated with a friction reducing material such as Teflon, graphite, boron nitride or moly-disulfide. The parachute line may be braided or may be constructed as a line strand core encased with a cladding of the friction reducing material around which the second line strand material is arranged. The line strands are preferably selcted from the line strands of Spectra and Aramid.

Description

LINE HAVING HYBRID FIBERS TREATED WITH FRICTION REDUCING MATERIAL

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is related to and claims the benefit of United States provisional patent application number 60/547,710 entitled "Parachute Lines Having Hybrid Fibers" filed February 25, 2004 and incorporated fully herein by reference.

BACKGROUND INFORMATION [0002] Field of the Invention

[0003] The present invention relates to construction of lines and more particularly, it relates to parachute, paraglider and other types of lines formed from different types of fibers and wherein the line is treated with a friction reducing material. [0004] Discussion of Related Art [0005] Parachute, paraglider and other high strength outdoor use lines have many conflicting requirements for effective use. The main considerations to be made in choosing a line are strength, elasticity and dimensional stability, drag, wear and safety. Aerodynamic Drag is affected by how thick the line has to be to achieve a necessary strength. Safety relates to how the line performs over time and is affected by use, including resistance to friction, abrasion and UV rays. Generally, parachute lines are formed from fibers which are maypole braided into a strong, thin rope. The general fiber types used are Dacron, Spectra, Vectran, and HMA.

[0006] Vectran, HMA and other ara id fibers are usually very dimensionally stable. They have a low elasticity and do not shrink due to frictional heat from the grom ets on parachute's slider during deployment. This makes the fiber very desirable for high performance canopies. However the material is damaged by UV rays and during use exhibits microfilament fractures that are difficult to see. Most parachutists due not replace the lines exactly on time as per the manufacturers recommendations and many parachutists do not even keep accurate logs of the number of jumps put on their canopy. Therefore it is not uncommon to see these lines catastrophically break in use, wherein serious injuries and deaths have occured.

[0007] Spectra is less dimensionally stable than the other fibers. However, it is the safest material to use as tends not to catastrophically fail. It changes dimensions before reaching the end of its usable life which effects the aerodynamic properties of the canopy, It also frays into an easy to spot fuzzy area when fractured, thus prompting the user to replace the lines before they reach a point where they might break.. The negative is that this change in line dimensions can occur long before the end of the usable life. Therefore there is a need for a line with the wear properties of spectra (UHMWPE) with the dimentional stability properties of fibers such as technora (HMA) [0008] There have been attempts in the paraglider industry to mix Spectra and Aramids to produce a line with the dimensional and temperature stability of the Aramid but with the safety of Spectra. Such trials were made by circular braiding one fiber type around a center core of the other. The tests were not successful since the fibers have differing elasticity, one fiber type would load and move more than the other forming a sawing action, which caused premature failure of the line.

[0009] SUMMARY The present invention is a line formed from different fibers in order to obtain the benefits of each without the problems seen in other hybrid lines. A hybrid line according to the present invention includes either core claded line, or a braided construction line using two or more types of fiber. According to an embodiment of the present invention, the hybrid line includes fibers of Spectra, Aramid, HMA or PBO. The hybrid line assembly or one or more of the individual fibers are coated, impregnated or otherwise treated with a friction reducing material such as low friction polymers and other equivalents, that prevents the sawing failure from movement of fibers having different elasticity's.

[0010] Tested coating or impregnation materials includeTefIon, boron nitride, moly-disulfide, graphite and other low friction polymers. Any type of coating or impregnation method may be used to treat the interface between the two types of fibers to help reduce the abraiding action between differing fiber types and to provide a low friction between the fibers. [0009] It is important to note that the present invention is not intended to be limited to a system or method which must satisfy one or more of any stated or implied objects or features of the invention. It is also important to note that the present invention is not limited to the preferred, exemplary, or primary embodiment (s) described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the allowed claims and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS [0010] These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein: [0011] FIG. 1 is a schematic drawing of the treated, multifiber line according to a first embodiment of the present invention showing a line having a core with a cladding; and [0012] FIG 2 is a schematic drawing of a braided treated, multifiber line according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] In the first embodiment of the treated, multifiber line 10, FIG. 1 according to the present invention, the line 10 is constructed of a central core strand material 12 around which is arranged a second strand material 16. Examples of uses for the treated, multifiber line of the present invention includes parachute lines, paraglider lines, and other commercial or recreational uses for lines including, rescue lines, rocker or mountain climbing lines, window washing lines, etc.

[0014] The first and second strand materials 12, 16, are made of different materials selected to provide the appropriate and desired dimensional stability, drag and elasticity. Examples of preferred line strand materials include spectra, aramid, HMA and PBO.

[0015] The central core strand material 12 consists of either loose, twisted, or circular braided fibers 13. The second strand material 16 typically consists of circular braided strands . [0016] Typically, the core strand material 12 will be of one type of material while the second or outer cladding 16 will be of a different type of material although this is not a limitation of the present invention as both the first and second strand materials 12, 16 may include multiple types of material . [0017] Because material like Spectra is more resistant to ultraviolet light, it is typically used as the cladding while materials like arimid are used as the core material. [0018] The treatment with a friction reducing material can be accomplished in one of several ways. For example, the individual fibers or individual strands used in the composite line may be individually coated or impregnated before being woven or braided. Alternatively, only one of the lines may be treated before being woven or braided. Lastly, the line itself may be treated once assembled. [0019] Methods of treatment include dipping the line or fibers in a bath of water or solvent containing the line strand friction reducing material in suspension, spraying the line or fibers, or vacuum deposition. In the case of dipping, it has been found that fine particulates of the friction reducing material suspended in a isopropyl alcohol base achieves a good result. In addition to the friction reducing material found in suspension in the base, other material such as emulsifying agents and binder materials may be added to assist in the process of coating or impregnating the line or fibers with the friction reducing material. [0020] Examples of friction reducing materials which provide the desired friction resistance include Teflon, boron nitride, graphite and moly-disulfide and other low friction polymers.

[0021] In another embodiment, the treated, multifiber parachute line 20, FIG. 2, includes a circular braided line made using multiple strands 12, 16 made of different materials. In the preferred embodiment, the circular braid consists of 16 carriers of fibers of two different types although this number of carriers is not a limitation of the present invention. The fibers are divided according to the line strength and other line characteristics desired. It is not necessary that the circular braid consists of one half of one type of fiber and one half of another type of fiber. The fibers criss-cross in a matrix before the hybrid line of the present invention. [0022] As mentioned with the core cladding line above, either or both of the first or second fibers may be coated or impregnated with a line friction reducing material prior to the braiding. Alternatively, the finished braided line may coated or impregnated after braiding has occurred. In addition, other processes such as a spray on or vacuum deposition technique may be used to provide the line friction reducing material to the braided line.

[0023] Accordingly, the present invention provides a novel, treated, multi-fiber parachute line which provides the benefits of a line having differing fiber strands yet which prevents the fiber strands from sawing or abrading against one another by means of an abrasion reducing impregnation material.

[0021] While the present invention has been described with a certain degree of particularity, it is obvious from the foregoing detailed description that one skilled in the art may make one or more modifications that are suggested by the above descriptions of the novel embodiments.

[0022] As mentioned above, the present invention is not intended to be limited to a system or method which must satisfy one or more of any stated or implied object or feature of the invention and should not be limited to the preferred, exemplary, or primary embodiment (s) described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the allowed claims and their equivalents.

Claims

CLAIMS The invention claimed is:

1. A treated, multiple fiber line comprising: a line including, in cross section, a first line strand of generally a first line strand material, and at least a second line strand generally of a second line strand material different from said first line strand material; and wherein at least one of said first line strand material, said second line strand material or said line is treated with a line strand friction reducing material.

2. The line of claim 1 wherein said first line strand material includes Spectra, and wherein said second line strand material includes an Aramid, hma or PBO.

3. The line of claim 1 wherein said line strand friction reducing material includes a low friction polymer.

4. The line of claim 1 wherein said line strand friction reducing material is selected from the group consisting of

Teflon, graphite, and boron nitride and moly-disulfide .

5. The line of claim 1 wherein said line is a braided line.

6. The line of claim 1 wherein said line includes a core of said first line strand material having a cladding of and generally surrounded by said at least a second line strand material .