JP2002172425A - Apparatus and method for straightening cross section shape of steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for straightening a cross section shape of a steel pipe capable of inexpensively and easily straightening circularity in the location separated from the tip end portion of the steel pipe. SOLUTION: The apparatus for straightening the cross section shape of the steel pipe is characterized by the feature that a jack mechanism to straighten circularity of the steel pipe by inserting it into the steel pipe to expand the pipe from the inner side, a mechanism to fix the jack mechanism into the inside of the steel pipe, a mechanism to operate the jack mechanism from the outside of the steel pipe, and a traveling mechanism having a tire for running the inside of the steel pipe to shift and hold the jack mechanism to a desired position is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for correcting the roundness of a steel pipe section at a steel pipe joint of a pipe truss structure.

[0002]

2. Description of the Related Art Steel pipes are widely used as structural members. In a truss-like structure using steel pipes, in order to accurately secure a gap at a groove when welding steel pipes to each other, a joint is required. The section of the steel pipe must maintain sufficient roundness. However, in general, the roundness of a steel pipe may be reduced due to plastic deformation received before construction, and it is not easy to secure a gap at a groove portion. As a method of correcting the cross-sectional shape of a steel pipe, there is a method of mounting a rotating roll mechanism on the inner circumference and the outer circumference of the steel pipe, and performing correction by contracting and expanding the cross section of the steel pipe. Also, Japanese Patent Application Laid-Open No. 58-47
No. 527 discloses a method using a hydraulic pipe expander in which a plurality of pipe expansion piston rods pressing the inner wall surface of a steel pipe are uniformly pressed while maintaining synchronization.

[0003]

However, these straightening methods aim at straightening the entire length of the steel pipe or at the end of the steel pipe. Also, the equipment used is complicated,
It is expensive and its installation, positioning, and removal are complicated. On the other hand, when constructing a pipe truss-like structure, it is common to weld the joint at a location away from the end of the steel pipe. In such a case, it is necessary to correct the roundness of the cross section of the steel pipe at the joint portion in order to secure a groove gap for welding. In this case, the cross section of the steel pipe to be corrected is often an elliptical shape close to a perfect circle.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can correct the roundness at a position distant from the end of a steel pipe at low cost and easily at a construction site. It is an object of the present invention to provide an apparatus and a method that can perform the method.

[0005]

The features of the present invention for solving the above-mentioned problems are as follows. (1) A jack mechanism for correcting the roundness of a steel pipe by inserting it into a steel pipe and expanding the pipe from the inside, a mechanism for fixing the jack mechanism to the inner surface of the steel pipe, and operating the jack mechanism from outside the pipe. A device for correcting a cross-sectional shape of a steel pipe, comprising a mechanism. (2) The device for correcting a cross-sectional shape of a steel pipe according to the above (1), further comprising a running mechanism having a tire that runs along an inner surface of the steel pipe and moves and holds the jack mechanism to a desired position. (3) A method for correcting the cross-sectional shape of a steel pipe, wherein the method is performed using the correction device according to (1) or (2).

The means for solving the problems according to the present invention is as follows. That is, it is a device for correcting the roundness of a steel pipe by a widening jack system, and has a configuration in which a load transmission shaft provided with a jack mechanism at a tip portion can be inserted into the inside of the steel pipe along the center axis thereof, Check the length of the load transmission shaft from the pipe end so that the jack mechanism of the straightening device can be attached to the joint welding point in the main pipe of the steel pipe for constructing the truss-like structure, and insert it outside the pipe. By applying a torque to the rear end of the load transmitting shaft, the jack is operated, and the pipe is expanded in the short axis direction in the cross section of the elliptical steel pipe to be corrected. In addition, by fixing the entire device to the steel pipe by the spring mechanism provided in the jack mechanism, it is possible to construct the pipe truss structure with the straightening device attached after straightening. This can keep the correction device from moving. Furthermore, by having the tire traveling mechanism with the spring mechanism attached, it is possible to insert the straightening device at the correct position when mounting the straightening device on the section of the steel pipe to be straightened, and after straightening, the entire device is straightened by the spring mechanism in the tire. Fixed to steel pipe.

[0007] According to the present invention as described above, in the construction of a pipe truss structure, the roundness of the steel pipe section of the joint portion located at a position distant from the pipe end of the steel pipe is determined by one short axis in the cross section. Therefore, the straightening device is simple and inexpensive, and the straightening method is simple as compared with the conventional tube expanding system in all directions in the cross section.

[0008]

Embodiments of the present invention will be described below.

FIG. 1 is a side view of a pipe truss structure, in which the elliptical cross section 1 on the main pipe side is corrected for roundness at a joint portion. The cross section 1 to be corrected is located at a position away from the end of the steel pipe by a joint depth L.

FIG. 2 is a side view showing an embodiment of the straightening device according to claim 1 of the present invention, and FIG. 3 is a front view thereof.

The straightening device of this embodiment has a joint depth L
The load transmission shaft 4 is longer than the load transmission shaft 4 and is disposed along a central axis of the steel pipe. A link-shaped jack mechanism 3 which expands and contracts in the radial direction of the steel pipe by a torque, a jack head 6 attached to a tip end of the jack mechanism 3, and a steel pipe attached to the jack head 6 via a spring mechanism 8; And a correction head 5 pressed against the inner surface of the head.

A correction method using the correction device of this embodiment will be described below. First, the load transmitting shaft 4 is inserted until the penetration depth from the pipe end reaches the joint depth L so that the jack mechanism 3 reaches the cross section 1. Next, the direction of the apparatus is adjusted so that the correction head 5 is directed in the minor axis direction of the elliptical cross section 1 to be corrected. After the positioning is performed in this manner, a torque is applied to the rear end of the load transmitting shaft 4 so that the jack head 6 spreads outward with respect to the center 7 of the jack.
Since the jack head 6 and the straightening head 5 are connected by a spring mechanism 8, the spring mechanism 8 contracts when the straightening head 5 hits the inner diameter of the steel pipe. The head 6 and the straightening head 5 come into close contact with each other, and thereafter, the torque given to the rear end of the load transmitting shaft 4 is transmitted to the straightening head 5 as it is, and the straightening head 5 spreads outward with respect to the center 7 of the jack to expand the pipe. Done.

FIGS. 4 and 5 are a side view and a front view, respectively, showing a state in which the roundness correction of the steel pipe is completed in the embodiment of FIGS. After the straightening, the torque at the rear end of the load transmitting shaft 4 is released, so that the jack head 6 slightly returns in the direction of the center of the jack 7 and the degree of adhesion between the jack head 6 and the straightening head 5 is reduced. As a result, the correction head 5 remains fixed to the inner diameter of the steel pipe, and the entire correction device is fixed. In the case where the pipe truss structure is installed with the straightening device mounted after the straightening, after the structure is completed, the straightening device is left installed inside the steel pipe. Although various loads such as vibrations are applied to the structure, the straightening device is securely fixed to the steel pipe by the above mechanism.

FIG. 6 is a side view showing an embodiment of the straightening device according to claim 2 of the present invention, and FIG. 7 is a front view thereof.

The straightening device according to this embodiment has, in addition to the straightening device according to the first embodiment shown in FIGS. 2 and 3, a frame 12 for supporting the jack mechanism 3, and a spring mechanism 9 attached to the frame 12. And a tire 10 mounted through the tire.

The straightening method by the straightening device of this embodiment is the same as that of the straightening device according to claim 1 shown in FIGS. 2 and 3, but when the straightening device is inserted into the steel pipe, the tire 10 (8 pieces in this embodiment) are brought into contact with the inner surface of the steel pipe, so that the entire apparatus is centered around the pipe axis so that the distance from the jack center 7 to the center of the tire, that is, the tire mounting height H is constant. The positioning of the straightening device to the steel pipe to be straightened is easy.

[0017]

The effects of the present invention described above are as follows. That is, in the construction of the pipe truss structure,
In order to correct the roundness of the steel pipe cross section of the joint part located at a position away from the pipe end of the steel pipe by widening one short axis in the cross section, a conventional method in all directions in the cross section is used. The straightening device is simpler and less expensive than the tube expansion method, and the straightening method is simpler.

[Brief description of the drawings]

FIG. 1 is a side view of a pipe truss member and a joint portion according to an embodiment of the present invention.

FIG. 2 is a side view showing one embodiment of the straightening device according to claim 1 of the present invention.

FIG. 3 is a front view showing one embodiment of the straightening device according to claim 1 of the present invention.

FIG. 4 is a side view showing a state after the correction in FIG. 2;

FIG. 5 is a front view showing the state after the correction in FIG. 3;

FIG. 6 is a side view showing an embodiment of the straightening device according to claim 2 of the present invention.

FIG. 7 is a front view showing one embodiment of a straightening device according to claim 2 of the present invention.

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1 Cross section of steel pipe to be corrected 3 Jack mechanism section 4 Load transmission shaft 5 Straightening head 6 Jack head 7 Jack center 8 Spring mechanism 9 Spring mechanism 10 Tire 12 Frame H Tire mounting height L From pipe end of steel pipe section 1 to be corrected Distance (joint depth)

Claims (3)

[Claims] A jack mechanism for correcting the roundness of the steel pipe by inserting the steel pipe into the steel pipe and expanding the pipe from the inside;
A device for correcting a sectional shape of a steel pipe, comprising: a mechanism for fixing the jack mechanism to the inner surface of the steel pipe; and a mechanism for operating the jack mechanism from outside the pipe. 2. The apparatus for correcting a cross-sectional shape of a steel pipe according to claim 1, further comprising a running mechanism having a tire that runs along an inner surface of the steel pipe and moves and holds the jack mechanism to a desired position. 3. A method for correcting the cross-sectional shape of a steel pipe, wherein the method is performed by using the correction device according to claim 1 or 2.