| 摘要 |
A sheave assembly for use in a high performance pulley block has an inner race 14, a sheave 10 defining an outer race and a plurality of balls 13 arranged between the outer race of the sheave 10 and the inner race 14, so as rotatably to mount the sheave on the inner race. The inner race 14 is formed principally of a plastics material, but incorporates an annular insert 20 of metal, the outer surface of the insert extending parallel to the axis of the assembly, and defining an inner track for the balls 13. The axial width of the insert 20 is significantly less than, and typically 33% to 67% of, the diameter of the balls 13. |
