| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost sling having strength and expansion rate similar to those of normal products, and having a function for warning of its limit of use, using colors, based on the elongation and degradation of the product. SOLUTION: The sling is of a three-layered structure consisting of a surface layer part, a core layer part and a back layer part formed of threads made from the same material in the same color. Colored threads whose colors differ from the color of the threads constituting the layers are woven in between adjacent layers. |
