초록 ▼

An improved machine for forming a plurality of thin, spiral grooves in the inner surface of a metal pipe. A grooving plug is inserted and held in the metal pipe in such a manner that its axial position is constant and the metal pipe, while being moved longitudinally, is pressed by a plurality of bal

An improved machine for forming a plurality of thin, spiral grooves in the inner surface of a metal pipe. A grooving plug is inserted and held in the metal pipe in such a manner that its axial position is constant and the metal pipe, while being moved longitudinally, is pressed by a plurality of balls which rotate planetarily around the outer surface of the metal pipe at a position corresponding to the position of the grooving plug to continuously form a plurality of spiral grooves in the inner surface of the metal pipe. Thereafter, the metal pipe is finished through a die. The machine manufactures at a high rate metal pipe which has a smooth outer surface and a grooved inner surface.

대표청구항 ▼

A machine for grooving an inner surface of a moving metal pipe comprising: a tie rod insertable into said metal pipe; a grooving plug rotatably mounted on a front end of said tie rod; a floating plug fixedly secured to a rear end of said tie rod; a rotary head; a first die proposed at a position cor

A machine for grooving an inner surface of a moving metal pipe comprising: a tie rod insertable into said metal pipe; a grooving plug rotatably mounted on a front end of said tie rod; a floating plug fixedly secured to a rear end of said tie rod; a rotary head; a first die proposed at a position corresponding to a position of said floating plug, said first die being adapted to hold said grooving plug at a predetermined position in said rotary head; said rotary head being disposed downstream of said first die; a plurality of balls planetarily rotatably arranged in said rotary head to press a wall of said metal pipe against said grooving plug in said metal pipe so as to reduce a diameter of said metal pipe; and a second die arranged downstream of said rotary head, for finishing said metal pipe thus processed.