CABLE CONDUIT WITH RIDGED INNER WALL

摘要

An electrical conduit for wires or cables is formed by a tube extending along a longitudinal axis and having an inner wall formed with a plurality of longitudinally throughgoing ridges each formed by a plurality of longitudinally joined sections with every other section inclined oppositely relative to the axis to the intervening sections. In other words the ridges run alternately along a right-hand helix and then a left-hand helix. The sections may be of varying pitch and part circular in section. They can also be substantially identical in which case they are straight, meet at corners, and are all of the same pitch.