A Variable Diameter Chain Bending Mandrel

Abstract

The invention discloses a variable-diameter chain-type pipe bending mandrel. The variable-diameter chain-type pipe bending mandrel comprises a plurality of roller core heads, sleeving links and cotterpins, which are all mounted in a pipe fitting, wherein the adjacent roller core heads are hinged by the length-adjustable sleeving links to form a planar link mechanism of which hinge points are theroller core heads; two sleeving links are respectively arranged at two ends of each roller core head; and the sleeving links on two sides are hinged to roller core head shafts at two ends of the roller core heads and fixed on the roller core head shafts at the end parts of the two ends of the roller core heads through the cotter pins to be prevented from dropping off the roller core head shafts. The problem of collision between mandrel sections at a big bending angle is solved while the inner wall of the metal pipe fitting is supported. The variable-diameter chain-type pipe bending mandrel canbe used for bending forming of pipe fittings with different diameters at different curvatures. The inner walls of the pipe fittings are supported, thus solving the problem that sections are distortedand corrugated in the bending forming process of the metal pipe fittings.

Description

technical field [0001] The invention relates to a mandrel for bending pipes, in particular to a chain-type mandrel for bending pipes with variable diameter. Background technique [0002] The mandrel is an important part in the bending process of the pipe fittings. Its function is to support the pipe wall from the inside of the pipe fitting to prevent the distortion of the pipe section and the wrinkling of the pipe wall. Existing elbow mandrels include round head mandrels, spoon mandrels, pivot pin mandrels, flexible shaft mandrels, and ball-and-socket mandrels. The round head type and spoon type are rigid mandrels. Although they are simple in shape and easy to manufacture, they are not suitable for bending and forming of pipes with different diameters; The mandrel is better, but it can only be bent in one direction; the flexible shaft mandrel is a ring-shaped mandrel with a soft rope in the middle, which can bend 360 degrees, but the distance between the mandrels is difficu...

AI Technical Summary

Problems solved by technology

The round head type and spoon type are rigid mandrels. Although they are simple in shape and easy to manufacture, they are not suitable for bending and forming of pipes with different diameters; The mandrel is better, but it can only be bent in one direction; the flexible shaft mandrel is a ring-shaped mandrel with a soft rope in the middle, which can bend 360 degrees, but the distance between the mandrels is difficult to control. And uneven; the ball-and-socket mandrel is made of multi-section solid spherical mandrel joints connected by ball joints, which can be bent 360 degrees, and the distance between the two core heads is fixed, but each mandrel at a large bending angle Collisions between sections

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