Synthetic sling whose component parts have opposing lays
A sling for industrial lifting made of a load-bearing core and a cover. The cover protects the plurality of yarns that make-up the core. Each core yarn is made of a number of core threads twisted together. The core yarns are twisted together where the twist is in the same direction as the individual core strands and a different direction than the twist of the cover. The present invention describes the method of twisting the core yarns together by inserting core yarns substantially parallel into a cover that has a twist opposite of each core strand. As the core strands are inserted into the cover, the twists of the individual core yarns interact with the twist of the cove, resulting in the core yarns twisting together.
1. A method of making a synthetic sling comprising the steps of:
providing an elongated tubular cover manufactured from threads having a twist in a first direction; and
inserting a plurality of core strands into said cover wherein each core strand has a twist in a second direction opposing said twist direction of the threads forming the cover, such that the opposing twist direction force the core strands into a helically twisting arrangement that forms a load-bearing core.
2. The method of claim 1 where the twist of the core strands is in the Z direction, the twist of the threads that form the cover is in the S direction, and the overall helical twist of the load-bearing core is in the Z direction.
3. The method of claim 1 where the twist of the core strands is in the S direction, the twist of the threads that form the cover is in the Z direction, and the overall helical twist of the load-bearing core is in the S direction.
4. The method of claim 1 where the twisting of the core yarns together is caused by the interaction of the twist of each core strand and the twist of the threads used to manufacture the cover.
5. The method of claim 1 where the twisting of the core strands together is caused by the friction between the directional twist of each core strand and the opposing directional twist of the threads in the cover.