straight line winds with blocking by roles in arbitrary positions.

摘要

The rectilinear jack comprises a cage defining an inner chamber at an upper portion while a lower portion of the cage is thinned out in order to form an end lug with a hole for fixation of the cage. The upper portion of the cage is substantially of a lozenge shape for enclosing a cam with two noses placed substantially at 120 DEG with respect to each other. The cam displaces two substantially V-shaped parts bearing on inclined inner walls of the inner chamber while an open lower portion thereof contains trains of rollers kept in engagement with the above parts by a spring. The trains of rollers bear on an upper portion of a jack stem having at least one connection head.