Abstract: A tube expander (10), for extrudably expanding the walls of a tube (12) is disclosed.The clamping force required on a tube (12) to prevent relative movement between the tube (12) and a tube expander (10), generally limits the amount of deformation completed during single stroke forming operations. The present invention provides a tube expander (10) for partially forming the tube (12) during insertion of the expander (10) into the tube (12) and fully forming the tube (12) during withdrawal of the expander (10). The tube expander (10) has an annular forming member (44) moveably mounted on a mandrel (22) for movement between a first position at which a plane (46) of the annular forming member (44) is at a skew angle with respect to a longitudinal axis (32) of the mandrel (22) and a second position at which the plane (46) of the annular forming member (44) is normal to the longitudinal axis (32).

Abstract: A method of connecting a tube (12) to a flange (120) is disclosed including placing the tube between first and second portions (14,16) of a holding apparatus (10), closing the portions and gripping the tube securely between the portions by operation of a first powered actuator (24), positioning a force-transmitting apparatus (20) including a punch (22) into axial alignment with the tube and flange, and forcing the punch axially into the tube and expanding the tube radially outwardly into interlocking engagement with the flange by operation of a second powered actuator (26) of the force-transmitting apparatus. The portions (14,16) are preferably pivotally closed to securely grip the tube, and the force-transmitting apparatus (20) is preferably an intergrated part of a computer controlled industrial robot (32).