RU2352421C2 - Method of shaped tubes straightening and mandrel for its implementation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method includes shaped tube force clamp by profile jaws, its detorsion and bending in directions, opposite to torsion and bending defects. Additionally before detorsion and bending in shaped tube it is introduced expanding profile mandrel, which is wedged till cavity fill of shaped tube with tension. Mandrel contains core with located on it directional elements and end stop with facilities of its fixing, while mentioned directional elements and end stops are implemented with ability of wedging and cavity filling of shaped tube with tension. Directional elements are reflector located on core. Each of them is implemented in the form of hub, connected with it conical wall of external flange, replicating internal shape of tube and separated by grooves for parts according to edges amount of shaped tube. Hub is displaced relative to ends of external flanges to the side of conical wall top. And each end stop is implemented in the form of resting to hub directional element of sleeve with clamp, located on it with ability of movement and fixation truncated pyramid and contacting with edges of mentioned wedges pyramid with its tightening band springs.

EFFECT: flattening improvement.

2 cl, 9 dwg, 1 ex

Description

The invention relates to the field of metal forming, and more specifically to methods and devices for cold straightening profile pipes by bending and torsion, and can be most effectively used to correct defects in axis curvature and twisting of pipe faces, for example, a square profile.

A known method of straightening the pipe and the mandrel for its implementation (see AS USSR No. 452391, M.cl. B21D 3/02, decl. 04/14/71, publ. 05.12.74).

This method is performed by rolling in rollers of a thin-walled cylindrical pipe mounted on a continuous cylindrical mandrel with simultaneous flattening of the pipe.

The disadvantage of this method is the impossibility of using it for straightening thin-walled profile pipes, for example, square or hexagonal profiles, having an axis curvature and curl of the faces, due to the impossibility of rolling in the pipe with rotating rollers.

The disadvantage of this mandrel is the inability to use it for straightening profile pipes, since a cylindrical, solid mandrel does not completely fill the hole of the profile pipe, which will lead to a violation of the profile of the pipe when editing.

Of the known methods for editing profile pipes, the closest in technical essence is the editing method described in A.S. No. 352696, M. Cl. B21D 3/12 stated October 16, 69, publ. 09/29/72

This method of editing profile pipes includes clamping the pipe with profiled jaws and twisting it in the direction opposite to torsion defects. When the pipe is untwisted, elastic deformation is reported that exceeds the initial twist angle.

Of the known mandrels for straightening pipes, the closest in technical essence is the mandrel described in patent RU No. 2049576, class. B21D 9/03 claimed 10/12/92, publ. 12/10/95, which contains a core with guide elements and end stops placed on it with means for fixing them. Between the guide elements mounted discs with plates in the form of combs.

A disadvantage of the known straightening method is the impossibility of correcting thin-walled profile pipes of square and hexagonal sections due to a change in the profile of the pipe in the cross section under the influence of elastoplastic moments of torsion and bending.

A disadvantage of the known mandrel is the inability to use it for straightening profile pipes for the following reasons:

1) the number of plates in the form of combs should be more than two - equal to the number of faces of the profile pipe, in particular four combs for a square pipe, six for a hexagonal pipe,

2) a mandrel can be inserted into a twisted and bent profile pipe only with a large gap, the size of which during editing will change the dimensions of the pipe profile.

The objective of the present invention is to provide a method for editing profile pipes with faces having torsional and bending defects, and a mandrel for its implementation, which allows for editing thin-walled profile pipes, for example square, hexagonal sections, without violating the dimensions of the pipe profile in the cross section by eliminating the loss of stability pipe walls when editing.

The problem is achieved by the method of editing profile pipes with faces having torsion and bending defects, including clamping the pipe with profiled jaws, twisting and bending in the directions opposite to torsion and bending defects, in this case, an expanding profile mandrel is introduced into the pipe before being unwound and bent, which wedged to fill the cavity of the profile pipe with an interference fit.

A mandrel for straightening profile pipes with faces having torsional and bending defects, characterized in that it comprises a core with guide elements and end stops placed thereon with means for fixing them, said guide elements and end stops being able to wedge and fill the profile cavity interference fit pipes, guide elements are mirrored on the core, each of them is made in the form of a hub connected to it by the conical wall of the outer shelf, repeating the inner the profile of the pipe and divided by grooves into parts in accordance with the number of faces of the profile pipe, the hub is offset from the ends of the external shelves by 1-3 mm towards the top of the conical wall, and each end stop is made in the form of a sleeve resting on the hub of the guide element with a shoulder located on it with the ability to move and fix the truncated pyramid and wedges in contact with the faces of the specified pyramid with bracelet springs pulling them together.

Such a constructive implementation of the method of editing profile pipes with faces having torsional and bending defects, and the mandrel for implementing this method will allow editing of thin-walled profile pipes (square, hexagonal and other sections) without violating the pipe profile in the cross section.

This is achieved by the method of straightening profile pipes with faces having torsional and bending defects, which makes it possible to increase the stability of the walls of thin-walled profile pipes in cross section due to the tight filling of the pipe with an elastic dispatch before dressing, which makes it possible to unwind and bend in directions opposite to torsion defects and bending by an amount ensuring the exclusion of these defects and obtaining pipes of the required quality. The value of bending and torsion is determined empirically for each standard size of profile pipes.

The use of a mandrel for straightening profiled pipes with faces having torsion and bending defects will ensure the stability of the thin walls of the profiled pipe and eliminate the violation of the shape and size of the cross section of the pipes during editing.

The guide elements, assembled specularly on the core, when compressed from the ends by bushings with collars, fill the elastic internal cavity along the entire length of the pipe by moving their shelves with conical walls in cross section.

The end stops located on the core at the ends of the internal cavity of the profile pipe rigidly fill the end parts of this pipe by moving the truncated pyramid relative to the wedges pulled together by bracelet springs, and allow these end sections to be used to rigidly clamp the profile pipe in the dressing and application mechanisms of torsion and bending. The axial displacement of the wedges is limited by focusing them on the shelves of the guide elements.

To explain the invention, a specific embodiment of the invention is provided below with reference to the accompanying drawings, in which:

figure 1 shows a mandrel for editing profile pipes with faces having torsion and bending defects, a longitudinal section;

figure 2 is the same, view a in figure 1;

figure 3 is the same, a section bB in figure 1;

figure 4 is the same, a section bb in figure 1;

figure 5 is a guide element, front view;

figure 6 is the same, Whig G in figure 5;

Fig.7 is the same, view D in Fig.6;

in Fig.8 is the same, a cross-section EE in Fig.5;

figure 9 is the same, a section FJ in figure 5.

The method of editing profile pipes with faces having torsion and bending defects is as follows. Before editing, in the profile pipe, for example a square one, having an axis curvature and twisting of the faces above the permissible limits, an expandable profile mandrel is inserted. The mandrel is wedged to tighten the pipe cavity. The pipe is clamped with profile jaws. Editing the pipe is carried out by unwinding and bending it in the directions opposite to its defects while holding it at the places of installation of the end stops.

The mandrel for editing profile pipes with faces having torsion and bending defects comprises a core 1 with guide elements and end stops having fixation means placed thereon. Each guide element is made in the form of a hub 2 connected by a conical wall 3 with an external shelf 4, repeating the internal profile of the pipe. The outer shelf 4 is divided by grooves 5 into parts in accordance with the number of faces of the profile pipe. The hub 2 is offset from the ends of the outer shelves 4 by 1-3 mm towards the top of the conical wall 3, which acts as a Belleville spring.

The offset of the hub relative to the ends of the outer shelves is designed to sample the gaps between the shelves of the guide elements and the pipe.

With a shift of less than 1 mm, this gap is not enough to install the mandrel in the pipe and tighten it tightly.

When the hub is displaced relative to the ends of the outer shelves more than 3 mm, the guide element loses the properties of a Belleville spring when tightened and collapses.

The guiding elements are mounted mirror to each other and with a gap in the pipe.

Each end stop is made in the form of a sleeve 6 resting against the hub of the guide element of the sleeve, on which a truncated pyramid 7 is mounted with the possibility of movement and fixing, the wedges are in contact with their faces 8. The wedges 8 are equipped with bracelet springs that tighten them 9. The means for fixing the guide elements and end stops are made in the form of a spacer sleeve 10 and nuts 11, 12.

Example:

The assembled mandrel with loose nuts 11, 12 is freely inserted into the square pipe 13, which has axis curvature and twisting of the faces above the permissible limits, then the nuts 12, 11 are sequentially tightened. When tightening the nuts 12, the gaps “a” between the guide elements and the pipe 13 are selected, and when tightening the nuts 11 of the pyramid 7 with wedges 8, the end stops in the pipe 13 are wedged. Thus, the square pipe 13 with a certain interference is filled with guide elements and end stops.

Editing pipe 13 with a mandrel installed in it is performed on a bending and twisting machine (not shown). The pipe is fixed at the end stops in the calipers of this machine and untwisted in the directions opposite to the defects of bending and torsion by an amount determined experimentally by statistical means.

The proposed method for editing profile pipes with faces having torsional and bending defects, and a mandrel for its implementation allow editing of curved and twisted pipes while preserving the shape and dimensions of the cross-sectional profile of the pipe.

Claims (2)

1. A method of straightening profile pipes with faces having torsion and bending defects, including clamping the profile pipe with profiled jaws, twisting and bending in directions opposite to torsion and bending defects, wherein an expanding profile mandrel is introduced into the pipe before being untwisted and bent, which wedged to fill the cavity of the profile pipe with an interference fit. 2. A mandrel for straightening profiled pipes with faces having torsional and bending defects, characterized in that it comprises a core with guide elements and end stops placed thereon with fixation means, said guide elements and end stops being made with the possibility of wedging and filling cavities of the profile pipe with an interference fit, the guiding elements are mirrored on the core, each of them is made in the form of a hub connected to it by the conical wall of the outer shelf, repeating the inner the first profile of the pipe and divided by grooves into parts in accordance with the number of faces of the profile pipe, the hub is offset relative to the ends of the external shelves by 1-3 mm toward the top of the conical wall, and each end stop is made in the form of a sleeve resting on the hub of the guide element with a shoulder located on it with the ability to move and fix the truncated pyramid and wedges in contact with the faces of the specified pyramid with bracelet springs tightening them.

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