Electric resistance heating jig for heat treatment of tubes - has fixed and mobile arms with tongs on respective opposite sides of trolley

摘要

A housing has a drive unit for moving a trolley vertically along guides. On one side of the trolley is a fixed arm (I) carrying tong arms, and a pivot mounting for a lever actuated by a work cylinder, so a rod can force the tong arms apart. On the other side of the trolley is a mobile arm (II), which carries the same devices as arm (I). But arm (II) can be moved to permit the tongs to clamp tubes with different lengths. A tube is clamped in the jig, and electricity is fed through the tong arms to heat the tube to a desired temp. The tube is then cooled, esp. by lowering the trolley so the tube enters a tank contg. a quenching liq. Used for thin walled tubes, e.g. with max. outside dia. of 50 mm, where the tube is securely clamped so it does not distort during quenching.