APPARATUS FOR EXPANDING TUBES Russian patent published in 1998 - IPC

FIELD: expansion of tubes flush mounted in tube walls for additionally joining them with tube wall by welding along perimeter. SUBSTANCE: apparatus for tube expanding includes rod whose one end is connected with piston of power cylinder. Movable and stationary pistons are mounted on said rod. Said pistons have cone end surfaces with the same cone angle equal to 130-145 degrees. Elastic sleeve is also mounted on said rod. Between ends of said elastic sleeve and respective piston, slit insert and intermediate ring are arranged respectively. Surfaces of slit inserts reciprocal relative to surfaces of both pistons have the same cone angle equal to 130-145 degrees. Stationary piston is freely mounted on said rod and rigidly fixed in housing of power cylinder for preventing its axial motion at expanding process. Said piston has rest engaging with tube wall at placing in its operating position. EFFECT: improved design. 5 cl, 1 dwg