Brake apparatus to retard relative movement between two members

摘要

A brake apparatus is provided to retard the relative movement between two members. The apparatus comprises a housing positioned around the perimeter of a portion of one of the members. A collar is fixedly secured to the housing generally around the perimeter of a portion of one of the members. Clamping elements are fixedly secured to the collar and have a first surface positioned generally coaxial with at least one of the members. The clamping elements move radially to frictionally engage one of the members to apply a braking force. Each of the clamping elements have a ball in abutting rolling relationship with a second surface generally radially opposite the first surface. The balls urge each of their respective clamping elements into such frictional engagement upon axial movement of an actuating device having a third surface in rolling engagement with the ball. One of the second and the third surfaces has a preselected incline with respect to a longitudinal axis of one of the members.