GEAR FOR EXPANDING OF PIPES Russian patent published in 2000 - IPC

FIELD: drilling of holes; invention is designed for expanding of overlapping units made of profile pipes installed in hole. SUBSTANCE: proposed gear has body with central passage and recesses in outer surface where rollers are installed with the use of axles inclined with reference to axis of body. Recesses are so made in the form of longitudinal cylindrical grooves in body that larger part of side surface of rollers is enveloped by walls of grooves and axles of rollers are anchored fast and releasably in body with one ends and their other ends are provided with tail parts located in grooves. Surfaces of tail parts protruding from grooves form together with surface of nipple end of body untouched by grooves common conical surface that has nipple thread. It is advantageous to screw fixing rod in the form of bushing on to thread in recesses. EFFECT: increased operational reliability of gear. 3 cl, 3 dwg