Frictional Hold of Various Sheave Configurations on Synthetic Ropes

摘要

Thirty eight test series were conducted using eleven different sheave configurations, two sizes of polyester rope, and one size of nylon rope. Tests were conducted with a taut line wrapped around a rotating sheave in both wet and dry conditions. Friction coefficients were measured continuously from static to slipping condition. The test variables include line tension, sheave diameter, line diameter, groove geometry, groove surface roughness, groove coating material and speed of sheave rotation. The coefficient of friction was found to decrease with decreasing groove surface roughness, decreasing sheave diameter, increasing enclosed angle of the groove and increasing line tension. The rougher surfaces rapidly destroyed the line and are not recommended for use with traction winches. The frictional hold decreased as the line was wearing against the sheave surface. For traction winch design, a V-groove steel sheave with a smooth surface is recommended for polyester 2-in-1 braid. The nylon lines have approximately 10% greater frictional hold than polyester lines. (Author)