INTERNAL CLAMPING APPARATUS

摘要

PROBLEM TO BE SOLVED: To achieve stable misalignment correction even when large diameter enlarging force is required like a butted part in the ends of a small diameter and thick wall-steel tube.

SOLUTION: An internal clamping apparatus is provided which is arranged inside the steel tubes P1, P2 and which diametrically enlarges and corrects the ends of steel tubes by imparting diameter-enlarging force from the inside to the butted ends of the steel tubes. The internal clamping apparatus includes: a pair of hydraulic cylinders 10 which are arranged in a casing so as to be opposed to each other and move their piston rods toward the butted part M at the ends of the steel tubes situated in the middle portion of the casing; a pair of wedge-shaped rods 11 which are provided in the movable parts of the cylinders and on each of which an inclined part is formed on the circumferential surface so as to reduce the diameter of the wedge-shaped rod toward the distal end; a plurality of plungers 12 each of which has an inclined sliding part 12A slid on the inclined part 11A of the wedge-shaped rod and is moved radially outward in the steel tubes by sliding of the sliding part 12A on the inclined part of the wedge-shaped rod; and a clamp shoe 13 which pressurizes the butted part from the insides of the ends of the steel tubes on which circumferential weld is performed.

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