Effect of Groove Shape on the Frictional Hold of a Sheave on Polyester Rope

This paper discusses the effects of sheave groove shape, sheave diameter, and line tension on the frictional hold of polyester rope. A series of tests were conducted using five different sheaves, 5 and 9.2-cm-dia 2-in-1 polyester rope, under both wet and dry conditions. The frictional hold was determined from the difference in rope tension on opposite sides of a rotating sheave. The maximum tension on the high side was 245 kN. It was found that the coefficient of friction between polyester rope and smooth steel sheaves decreases with increase in rope tension for a given rope size. The 70-deg-V groove sheave shape demonstrated approximately 25 percent more frictional hold than the U-groove sheave shape. Holding capacity increases with sheave diameter. Large relative velocity exists between elastic lift line and sheave surface. Data will be used in a traction winch design.