| 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). |
