This application claims priority under 35 U.S.C. §119 of European Patent Application No. 06004821.2, filed on Mar. 9, 2006, the disclosure of which is hereby incorporated by reference thereto in its entirety.
1. Field of the Invention
The invention relates to a load bearing system that includes a load bearing textile strap.
More particularly, the invention is directed to such a strap for any application in which a load is required to be spread along a contacting surface. For example, such applications include those in which an object is to come in contact with a portion of a body of a person using such object, such as climbing harnesses, backpack shoulder straps, backpack hip belts, ski pole straps, medical slings, automobile seat belts, bag carrying straps, etc.
The invention is also directed to other categories of applications, such as, for example, industrial lifting slings. Indeed, in such applications, the load-spreading feature according to the invention, further described below, can be implemented to considerable advantage with regard to the load bearing system of the invention and the object with which it comes into contact.
2. Description of Background and Relevant Information
In current applications that use a load-bearing strap, a cushioning pad may be provided adjacent the strap, so that the cushioning pad is interposed between the strap and the user's body in order to avoid direct contact. The cushioning pad is sometimes wider than the load-bearing strap, but usually by only small amount if at all. Moreover, the cushioning pad being basically soft, it has a significant load-spreading effect only very close to the edges of the strap. Therefore, the load is not properly spread and may result in too much contact pressure on the body, causing undesirable effects.
In order to achieve better spreading of the load, it is known to use variable width textile straps. Such straps are woven in a specific way at predefined positions along their length, most of the time by modifying the weaving parameters in a specific section of the strap. Typically, such techniques allow the width of the strap to be increased at those specific predefined locations up to double the nominal width of the strap, but not more. Such techniques increase the production cost of the strap and they show no flexibility: once the strap is woven, the location, shape, and measurements of the portions of increased width cannot be adjusted to each specific application.
Such variable width straps do achieve a load spreading effect, but they are limited by the maximum width increasing ratio. Other constraints include having to weave a specific strap for each specific application.
In view of the current state of the art, an object of the invention is to provide a new construction for a load bearing system which achieves a desired load bearing effect in an easy, flexible, low-cost and effective way.
Toward this end, the invention provides for a load bearing system that includes a load bearing textile strap, the strap including a woven portion having warp yarns extending along a longitudinal direction of the strap interlaced with at least one weft yarn, the woven portion of the strap having a first width, the strap having a non-woven portion including only at least a part of the warp yarns, and, in the non-woven portion, the warp yarns being spread transversely so as to spread over a second width greater than the first width of the woven portion.
Other characteristics and advantages of the invention will be better understood upon reading the following description, with reference to the attached drawings showing, by way of non-limiting embodiments, how the invention can be embodied, and in which:
Because
The woven portion of the strap has a first width. Although the first width could vary along the length of the woven portion (as known in the prior art), the first width is substantially constant along the length of the non-woven portion.
According to one aspect of the invention, a strap 10 is provided having a portion in which the weft yarn is absent, that is, a non-woven portion 16.
In the example shown in
Such non-woven portion 16 could be made simply by interrupting the weaving process, namely by interrupting the interlacing of the weft yarn(s) with the warp yarns on the weaving loom, while allowing the warp yarns to advance through the loom. Therefore, after a first upstream woven portion 18 has been woven, the weaving process would be interrupted for a period of time corresponding to the time necessary for the desired length of the non-woven portion to advance through the loom. Then, the weaving process would resume in order to weave the adjacent downstream woven portion 20. A strap 10 with a built-in non-woven intermediate portion 16 could therefore be directly produced in such way.
In
A particular advantage of this process is that it is possible to use almost any standard strap, so that the strap can be sourced in great quantities for a variety of applications. Indeed, with a given standard strap, it is very easy to adjust the length and position of the non-woven portion(s) relative to the length and position of the woven portions, keeping full flexibility in the choice of the base strap depending on the application. To the contrary, a ready-made strap with built-in non-woven portions would not exhibit such flexibility.
The cutting of the weft yarn(s) may be done manually, as indicated in
As can be seen in
Various techniques can be used to maintain the warp yarns in the spread-apart configuration.
One such technique that can be employed is to make a series of transverse stitches to stitch the warp yarns 12 to a support surface. Such support surface can be any kind of textile material, or a laminate material, or a film, or other support surface.
According to one alternative aspect of the invention, however, the warp yarns 12 can be very effectively maintained in their spread-apart configuration by adhesive bonding.
Depending upon the materials making up the yarns, different adhesive bonding techniques can be used. It is within the scope of the invention that, if the materials are compatible, the yarns can be affixed on a support surface by welding, for example ultrasonic or radio-frequency welding. However, in most cases, the adhesive bonding can be achieved through the use of adhesive materials such as glues or glue-containing compounds. Many types of glues can be used, such as, for example, polyurethane based glues. Such glues can be in the form of self-standing films or in liquid form. They can be thermo-activated glues, e.g., hot-melt glues. A glue-containing compound, for example, can be made of two or more films of hot-melt adhesive, including films of different compositions to adapt to the specific materials of the warp yarns on one side and of a support surface on the other side. The gluing compound could also possibly have an interfacial layer between two adhesive films. The interfacial layer could, for example, be a fabric layer or a foam layer.
In the illustrated example, the adhesive bonding is achieved through the use of a self-standing film of thermo-activated polyurethane glue 22. The film is, for example, pre-cut to a desired shape (which here corresponds to the shape of the non-woven portion 16 of the strap 10 and its spread-apart warp yarns 12) and simply heat-pressed onto the strap. By means of such heat pressing, the glue flows very intimately around each yarn and secures each yarn very solidly. Indeed, in contrast with a tightly woven web, where the tight interlacing might prevent the glue from perfectly bonding to the fibers (unless a perfect match of temperature, glue flow rate and glue quantity is achieved), the spread-apart warp yarns can be relatively easily perfectly bonded. That is, as can be seen in
As shown in
In any case, in a particular aspect of the invention, the glue film(s) has (have) a length greater than the length of the non-woven portion in order to cover not only the non-woven portion 16, but also neighboring parts 17, 19 of the woven portions 18, 20. Indeed, the film of glue therefore not only maintains the warp yarns 12 in a spread-apart configuration, but also prevents the terminal transverse edges of the woven portions 18, 20 from fraying.
The strap therefore exhibits a load-spreading portion of having an increased second width compared to the first width of the woven portion. The load-spreading portion is made without compromising the amount of load that the strap can withstand since the warp yarns 12, which bear most of the load, are continuous through both woven portions 18, 20 and through the non-woven portion 16.
The strap and its load-spreading portion can be totally or partially encased in a flexible casing or envelope made, for example, of two sheets of textile material joined along their respective edges. The load-spreading portions of the strap can, in such an embodiment, be glued inside the casing.
Adjacent the load-spreading portion of the strap, according to another embodiment, a cushioning layer can be provided, such as a foam layer, for example. Such cushioning layer can be glued onto the load-spreading portion. In case the load-spreading portion is encased in a casing, the cushioning layer may be contained, for example, within the casing.
The embodiment described above has a non-woven portion in an intermediate location between two woven portions of the strap.
An embodiment like that of
In such an embodiment, it can be seen in
An exemplary application of the invention is shown in
A securing ring 40 is secured on the front part of the waist belt and a link strap 42 connects the two leg loops 34 while passing through the securing ring 40.
As can be seen in
The two leg loops 34 are constructed in a similar way with a load-bearing strap 10 which is closed on itself (here in a non-adjustable manner, for example through adequate stitching of the two woven extremities of the strap), the strap having a non-woven back portion 16 (also encased in a supple/flexible casing 46) intended to come in contact with the back of the user's thighs.
A climbing harness constructed as described above and shown in
The incorporation of the load bearing system in a climbing harness can be varied according to many different embodiments, within the scope of the invention. For example, only the waist belt or only the leg loops can be constructed using a load bearing system according to the invention.
The load bearing system according to the invention can also be incorporated into a backpack, such as for shoulder strap(s) and/or a hip belt thereof, including into a backpack such as in accordance with the disclosure of U.S. Patent Application Publication No. 2006/0283907, published on Dec. 21, 2006, and commonly owned herewith, the disclosure of which is hereby incorporated by reference thereto in its entirety. For example, the load bearing system according to the invention could be incorporated in an intermediate portions of the shoulder straps 26 and/or of the straps 38, 40 of the hip belt of that application.
Other applications of the invention are also contemplated, whereby the load-bearing system described herein can be incorporated into various articles, such as backpack shoulder straps and/or hip belts, industrial lifting slings, ski pole straps, gear slings, gun straps, musical instrument straps, medical slings, etc., and for any application in which a load bearing strap is currently used.
Number | Date | Country | Kind |
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06004821 | Mar 2006 | EP | regional |
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