A shaping method for a double pipe includes: bending the double pipe with a specified curvature to form a bent portion in the double pipe; and arranging the bent portion on a first shaping die having a first shaping surface at a position biased inward or outward in a curvature radius direction of the bent portion relative to the first shaping surface, wherein the first shaping surface is configured to shape a first outer surface of both outer surfaces of the bent portion that are located on both sides of a plane including a central axis of the bent portion, and pressing the bent portion arranged on the first shaping die by a second shaping die having a second shaping surface configured to shape a second outer surface of the both outer surfaces of the bent portion.

A shaping method for a double pipe includes: bending the double pipe with a specified curvature to form a bent portion in the double pipe; and arranging the bent portion on a first shaping die having a first shaping surface at a position biased inward or outward in a curvature radius direction of the bent portion relative to the first shaping surface, wherein the first shaping surface is configured to shape a first outer surface of both outer surfaces of the bent portion that are located on both sides of a plane including a central axis of the bent portion, and pressing the bent portion arranged on the first shaping die by a second shaping die having a second shaping surface configured to shape a second outer surface of the both outer surfaces of the bent portion.

A mandrel 10 for producing a thin-walled bent tube having a bending portion with high strength and a small radius of curvature by rotary draw bending without either cracks in an outside of bend or wrinkles and buckling in an inside of bend occurring includes a shank 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L.sub.1/L.sub.2) between a dimension L.sub.1 from the mandrel ball center 17 to the first position 19 and a dimension L.sub.2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.

A mandrel 10 for producing a thin-walled bent tube having a bending portion with high strength and a small radius of curvature by rotary draw bending without either cracks in an outside of bend or wrinkles and buckling in an inside of bend occurring includes a shank 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L.sub.1/L.sub.2) between a dimension L.sub.1 from the mandrel ball center 17 to the first position 19 and a dimension L.sub.2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.

A bending head for an automatic bending machine includes a frame. A first rotationally driven bending roll is arranged in the frame. A bending arm is transversely arranged below the first bending roll and is coupled to a bi-directional drive, with an end of the bending arm rotatable about the longitudinal axis of the first bending roll. A rotatable second bending roll is mounted to an opposite end of the bending. A bending support is configured with the first and second bending rolls. The second bending roll is rotationally coupled to the first bending roll in a forced torque transmission manner for mutual counter-direction rotation of the first and second bending rolls. The bending rolls have axially symmetric reduced lateral circumferential sections. The bending roll controls an angle of mutual rotation of both of the first and second bending rolls.

A bending head for an automatic bending machine includes a frame. A first rotationally driven bending roll is arranged in the frame. A bending arm is transversely arranged below the first bending roll and is coupled to a bi-directional drive, with an end of the bending arm rotatable about the longitudinal axis of the first bending roll. A rotatable second bending roll is mounted to an opposite end of the bending. A bending support is configured with the first and second bending rolls. The second bending roll is rotationally coupled to the first bending roll in a forced torque transmission manner for mutual counter-direction rotation of the first and second bending rolls. The bending rolls have axially symmetric reduced lateral circumferential sections. The bending roll controls an angle of mutual rotation of both of the first and second bending rolls.

The invention relates to a mobile hydraulic tool with a drive piston hydraulically adjustable between a start position and an end position, a hydraulic tool housing having a cylindrical section guiding the drive piston, and a tractive tool unit or pressing tool unit releasably connectable to the drive piston and the hydraulic tool housing. In order to provide a mobile hydraulic tool in which the movement provided by the drive piston can be used to optionally drive a tractive tool unit and a pressing tool unit, the hydraulic tool housing is designed on one side for arranging the tractive tool unit connectable to the drive piston, and on the other side for arranging the pressing tool unit connectable to the drive piston.

A method of forming a hollow metal member may include stamping a metal blank to form half shell pieces that are configured to be approximately a half of a hollow metal member and stamping a another metal blank to form a half shell piece that is configured to be approximately the other half of the hollow metal member. The half shell pieces may be aligned to place the edges of the first and second half shell pieces in abutting contact. The half shell pieces may be welded together along seams that are defined at the abutting edges of the first and second half shell pieces. The attached half shell pieces may then be compacted to form the hollow metal member with reduced residual deformation from stamping and welding the half shell pieces.

Benders are disclosed relating to the convenient, accurate, and precise bending of tubing. Example benders include features such as a mandrel, adjustable mechanical stops, and scales having relatively high resolution along with significant distance from a central axis of the mandrel. Certain benders may include separate fine and coarse adjustments to bend angles and support mechanisms for controlling the bend plane angle.

Methods for forming thin wall tubing into a tightly-coiled helical duct comprise selecting a thin wall tube with an outside tube diameter and a wall thickness that is less than 15% of the outside tube diameter; and bending the thin wall tube to form the tightly-coiled helical duct so that an outside duct diameter of the tightly-coiled helical duct is less than four times the outside tube diameter.