Abstract: A tube expander includes an oil-discharging device for discharging a predetermined amount of oil into the tubes of a heat exchanger mounted on the tube expander which is movably mounted between tube-expanding mandrels of the tube expander and the heat exchanger. The oil-discharging device is provided with a plurality of oil-discharging nozzles each constructed of a pipe-shaped nozzle main body having an end expander bullet that can be inserted into a tube, an oil-discharging hole arranged between the nozzle main body and the expander bullet for discharging the oil, an annular sleeve mounted around the circumferential surface of the main body for reciprocal movement relative thereto, the annular sleeve having an end contact part for abutting against an opening end of the tube, the annular sleeve sealing the oil-discharging hole of the nozzle main body by means of a resilient member, and a stopper provided on an end of the expander bullet to receive the sleeve on the end of the expander bullet.

Abstract: The invention relates to an apparatus for automatically mounting and removing replacement pins for an attachment fixture to be mounted to a pipe expanding apparatus. The apparatus enables quick mounting and removal of replacement pins according to various different patterns formed in the attachment fixture and thus provides improved operating efficiency and improved productivity in connection with pattern changing.

Abstract: A pipe expanding apparatus comprising a reciprocating member to which a plurality of pipe expanding mandrels are attached to be capable of being inserted into a plurality of pipes to be expanded under pressure, a plurality of guide posts penetrating through the reciprocating member at desired locations for slidably guiding the reciprocating member, and extending and contacting apparatus which is mounted on a frame uprightly provided on a base, and is operated to reciprocate the reciprocating member for expanding the pipes. The extending and contracting apparatus is constituted by at least one pair of cylinders disposed at both lateral side ends of the reciprocating member, respectively, for inserting the mandrels attached to the reciprocating member into the pipes to be expanded under pressure when actuated.

Abstract: A structure for mounting mandrels in a tube expanding apparatus comprising a horizontal mounting plate fixed to the underside of a vertically movable slide and having a plurality of passage holes through which the mandrels suspendingly extend. The structure comprising a cylindrical holder non-fixedly provided on the mounting plate above each passage hole and having an internal gripping space for holding an upper region of each mandrel. The holder comprising a pair of cylinder halves movable toward and away from each other. A contractive rubber ring being fitted around the holder to force the cylinder halves toward each other into a joined state. The upper region of the mandrel being provided with a diametrically reduced, eccentric portion surrounded by an engaging groove. With one of the cylinder halves being internally formed with an arcuate projection which is selectively engageable with and disengageable from the engaging groove in response to the rotation of the mandrel relative to the holder.