The present invention relates to protective and safety anchoring systems used in the fields of climbing, sailing, rescue operations, etc. and more particularly to an improved climbing aid of the type known as a quickdraw or sling.
A quickdraw is a type of climbing equipment that comprises two carabiners that are connected by a sewn loop of webbing. While there are numerous variations on the basic quickdraw device that are available on the market, all are used to allow a climber to attach a climbing rope to a bolt or other protection while allowing the rope to run freely. In use, one of the carabiners of the quickdraw is clipped to a bolt (or other protection). The rope is then run through the other of the two carabiners.
Typically, woven nylon webbing is used to connect the two carabiners. The fabric is formed into a loop by circling a length of webbing over itself and so that the loop has a double layer of webbing. The ends of the length of webbing are overlapped and the loop is sewn together with stitching such as, traditionally, bar tacking, resulting in a closed loop having at least a portion of the webbing in a double, even triple layer. The bar tacking defines openings on both ends of the loop—the carabiners are attached to the loops.
The woven fabric used in quickdraws is strong and meets the applicable standards developed for equipment used in climbing. However, the webbing used in conventional quickdraws can wear over time, making routine inspection important.
Quickdraws are often used in indoor climbing gyms. In these uses, the quickdraw is often clipped onto the protection with a locking carabiner and the device is left in place on the climbing wall. Because the device remains on the wall for an indefinite period of time and is possibly subject of less frequent inspection, there is a need for a quickdraw that is strong and less prone to wear than conventional quickdraws.
The present invention is a quickdraw device in which the strength of the webbing has been increased by the specific manner in which the webbing is looped and sewn. Surprisingly, it has been discovered that by adding another layer to the fabric in the loop and by arranging the ends of the webbing in a specific arrangement, the fabric to fabric strength of the webbing is substantially increased. Thus, in the present invention the length of fabric in each loop is overlapped so that the entire loop is defined by four-layered webbing with double-layers of webbing where the carabiners contact the quickdraw, and where the opposite ends of the webbing do not overlap.
The invention will be better understood and its numerous objects and advantages will be apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings.
A prior art quickdraw 100 is shown in
In the prior art, the fabric loop 16 is defined by a length of webbing that has its opposite ends overlapped and sewn together to define the two carabiner-attachment loops through which the carabiners are attached. Notably, there is only a single layer of webbing in the loops where the carabiners attach to the fabric loop and three layers of webbing where the opposite ends of the webbing overlap.
A first embodiment of a quickdraw 10 according to the present invention is shown in
With continuing reference to
The fabric loop 16 is defined by a length of webbing that is formed in a loop such that the webbing is doubled over on itself until the ends 24 and 26 are almost even with each other but not overlapping. The loop 16 is pressed flat so that the splice—that is, the region of in the central portion 18 where the facing first and second ends 24 and 26 meet is near the center of the flattened loop—in central portion 18—and the webbing is four layers thick throughout the central portion 18. The thus-oriented webbing is then securely sewn through all four layers on both sides of the splice, leaving the openings 20, 22 at each end of the fabric loop 16 for attaching a carabiner, 12 and 14. The sewing is conventional: the webbing is sewn together longitudinally with conventional sewing techniques—the longitudinal stitching is not visible in the drawings to better illustrate the types of stitching that may be used to interconnect the layers of fabric. As noted above, bar tacks are one traditional type of stitching that may be used and in the drawings plural bar tacks 28 are sewn into the center portion 18 and the bar tacks define the openings 20 and 22. It is to be understood that instead of bar tacking computer driven pattern stitching may be used to stitch the layers together in center portion 18 and the stitching may be in any particular pattern that is programmed into the sewing machines. Even with computer driven patterns, the traditional “appearance” of bar tacking may be beneficial because consumers tend to recognize the traditional bar tacking patterns and thus have confidence in the product even though other, computer driven patterns are functionally and operationally superior in many cases. The longitudinal stitching is done prior to the bar tacking, and helps to keep the layers from separating, especially in the openings 20 and 22. This helps prevent inadvertent insertion of a carabiner through only one layer of webbing in the openings.
The fabric used to form loop 16 may be conventional woven nylon webbing that is used in climbing applications. The webbing may beneficially incorporate or comprise the high-strength ultra-high molecular weight polyethylene fibers.
A quickdraw 10 formed as shown in the drawings and as described above has unexpectedly high strength. The specific arrangement of the webbing to define a central portion 18 that has 4 layers of webbing is the reason for the surprisingly high strength of the quickdraw.
Turning to the embodiment of
The quickdraw 10 according to the present invention has been tested and results show that the breaking strength for the quickdraw as claimed herein is about 1.3 to 1.4 times greater than the breaking strength of a conventional quickdraw having a single wrap as shown in
The internationally accepted minimum breaking strength for a climbing sling such as a quickdraw 10 is 22 kn. A conventional quickdraw manufactured by the assignee of the present application (Metolius Mountain Products, Inc.) typically breaks at 26 to 27 kn; a 15% margin of extra strength is preferred for a safety margin. A quickdraw 10 according to the present invention, fabricated with the same webbing in the double wrap configuration as specified herein breaks at 36 to 37 kn. When a quickdraw fails in the field, it is typically because of age, wear, and abrasion. It is possible for a quickdraw to look old with some frayed fibers, but still be intact and appear to be reasonable to use, and yet be unsafe. The double wrap construction described herein and as shown in the drawings makes it much more difficult to have a situation where the sling looks usable but is actually unsafe.
Another advantage is that the double wrap sling according to the present invention will meet the 22 Kn standard if the outer wrap is completely destroyed by abrasion, cutting or UV light damage.
One more advantage of the quickdraw 10 according to the present invention is that with conventional quickdraw slings it is desirable to have a narrow sling profile at the end of the sling where the carabiner sits. Several prior art single wrap slings use a variable width webbing to accomplish this—the webbing is woven such that the main body of the quickdraw, for example at center portion 18, is 18 mm wide, then the webbing tapers down to 13 mm wide where it turns the corner where the carabiner attaches, then gets wider again for the main body. With the double wrap quickdraw 10 according to the invention described herein, this differential width webbing is not necessary and it is possible to use webbing that has the same width throughout the loop 16.
Reference is now made to the quickdraw 10 that is shown in
Returning to
While the present invention has been described in terms of preferred and illustrated embodiments, it will be appreciated by those of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims.
Number | Date | Country | |
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62356683 | Jun 2016 | US |