Patent ID: 6149133
Filing Date: 2000-11-21
Classification: B66D,F16H

Abstract:
A sheave for advancing a rope looped around said sheave by application of rotational forces thereto comprisinga central hub and opposed, facing first and second surfaces arcuately outwardly extending from said hub to an outer perimeter,each of said opposed surfaces being provided with alternating primary ridges and valleys extending from said hub to said outer perimeter, the primary ridges of said first one of said surfaces being aligned with a valley of the opposed second surface,said valleys being tapered in width toward said hub of said sheave and having a generally flat floor surface, the center of each said valley having a secondary ridge projecting from said floor surface, said secondary ridges each being of a height extending above its associated valley floor surface that is substantially less than the height of said primary ridges, each of said secondary ridges being in at least approximate alignment with a primary ridge of said facing sheave surface.