EVALUATION OF A NOVEL TORQUE REDUCING DEVICE

摘要

A torque reducing device, designed and built outside this Laboratory, was submitted for test and evaluation. It consists essentially of two nuts contained in a common housing and engaged on a common screw, two sets of balls and a cam surface. Each nut rolls on a set of balls which in turn roll on a cam surface contained in the housing. When the housing or cam surface is advanced, as set of balls under one nut will roll up the cam surface and force the nut and the screw in an axial direction against the load. The principle of operation is basically that of a wedge with rolling friction. The nut forcing the screw to move against the load does not move relative to the screw; thus only rolling friction is involved. While this nut is carrying the load, the other nut is loose in its screw threads and is advanced along the screw by a small frictional force between the nut and the housing. Thus, there is an intermittent action; one nut carries the load and advances the screw along its axis but does not move relative to the screw, while the other nut advances on the screw while carrying no load.