Provided is a device for manufacturing a bent pipe, the device being capable of reducing buckling. The device including: an inner core metal arranged inside a first pipe; and a bending mold to bend the first pipe. The inner core metal includes: an inner core metal body; a first inner movable portion coupled to the inner core metal body and swingable around a first rocking shaft orthogonal to a central axis of the inner core metal body; and a second inner movable portion coupled to the first inner movable portion and swingable around a second rocking shaft parallel to the first rocking shaft. The first inner movable portion has an enlarging diameter portion enlarged in diameter toward the second inner movable portion. The bending mold causes an inner surface of the first pipe to press the first inner movable portion and the second inner movable portion.

A device (10) is disclosed for bending hollow structural components (100), in particular pipes, having a mandrel shaft (40) for receiving a receiving element (20), wherein a row of at least two ball joints (30, 30) connected with each other can be inserted into the receiving element (20) at its end, wherein the row of ball joints (30, 30) is preferably lockable by a ball-and-socket joint (70) at an end located opposite the receiving element (20), wherein each ball joint (30, 30) of the row is circumferentially enclosed by a shingle (50, 50) and the ball-and-socket joint (70) is circumferentially enclosed by an end shingle (60) and the shingles (50, 60) overlap each other at least in portions.

A device (10) is disclosed for bending hollow structural components (100), in particular pipes, having a mandrel shaft (40) for receiving a receiving element (20), wherein a row of at least two ball joints (30, 30) connected with each other can be inserted into the receiving element (20) at its end, wherein the row of ball joints (30, 30) is preferably lockable by a ball-and-socket joint (70) at an end located opposite the receiving element (20), wherein each ball joint (30, 30) of the row is circumferentially enclosed by a shingle (50, 50) and the ball-and-socket joint (70) is circumferentially enclosed by an end shingle (60) and the shingles (50, 60) overlap each other at least in portions.

A clamp member and a counter pressure member are hingedly connected together about a rotary axis, and a fitting portion of a fitting protrusion that is positioned in a fitting recess is located at a foreside in an advancing direction of the pipe relative to a position where a bending operation of the pipe is initiated, and a mating portion at which a first groove part of the clamp member and a second groove part of a counter pressure member mate is located at a backside in the advancing direction of the pipe relative to the position where the bending operation of the pipe is initiated. The counter pressure member comprises a first member supported rotatably about the rotary axis, a second member detachably connected to the first member, and a third member detachably connected to the second member, which are connected together by a common connecting member (e.g., bolt).

A clamp member and a counter pressure member are hingedly connected together about a rotary axis, and a fitting portion of a fitting protrusion that is positioned in a fitting recess is located at a foreside in an advancing direction of the pipe relative to a position where a bending operation of the pipe is initiated, and a mating portion at which a first groove part of the clamp member and a second groove part of a counter pressure member mate is located at a backside in the advancing direction of the pipe relative to the position where the bending operation of the pipe is initiated. The counter pressure member comprises a first member supported rotatably about the rotary axis, a second member detachably connected to the first member, and a third member detachably connected to the second member, which are connected together by a common connecting member (e.g., bolt).

An apparatus for improving the quality of tube bending; adapted to be used in bending machines and comprises a substantially longitudinally extended mandrel, adapted to be inserted into a tube to be bent and having a rigid portion and a flexible portion arranged in series, the latter comprising a series of mandrel segments connected by articulated joints; the apparatus also comprises at least one motion-sensitive sensor, which is integral with at least one of the mandrel segments, and elements for processing the motion information acquired by the sensor.

An apparatus for improving the quality of tube bending; adapted to be used in bending machines and comprises a substantially longitudinally extended mandrel, adapted to be inserted into a tube to be bent and having a rigid portion and a flexible portion arranged in series, the latter comprising a series of mandrel segments connected by articulated joints; the apparatus also comprises at least one motion-sensitive sensor, which is integral with at least one of the mandrel segments, and elements for processing the motion information acquired by the sensor.

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 winkles 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 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 method and apparatus for bending a pipe to mitigate internal wrinkling, with particular benefit when bending a lined pipe upon spooling. Bending is performed continuously by advancing the pipe through a bending zone while an internal mandrel is held at the bending zone to resist wrinkling. In one variant, the mandrel comprises longitudinally-spaced pipeengaging elements and a tensile link between the elements allows relative movement between the elements. A holdback connection on one of the elements applies hold-back force to that element to be transmitted to the other element via the tensile link. In another variant, the mandrel comprises an elongate pipe-engaging body with a hold-back connection at one end of the body. The body is flexible to bend with the pipe and is shaped to engage an inner surface of the pipe along most of the length of the body.