JPH09158500A - Single pipe supporting member made of aluminium alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a single pipe supporting member while maintaining strength performance by forming the single pipe supporting member using an aluminium alloy in such a way that both end part outer diameter of the single pipe supporting member is smaller than the average outer diameter while the wall thickness is thicker than the average wall thickness and that the center part outer diameter is larger than the average outer diameter while the wall thickness is thinner than the average wall thickness. SOLUTION: The pipe end part outer diameter of a single pipe supporting member made of an aluminium alloy is reduced to about 90% or less of the average outer diameter, and the thickness is thickened to 110% or more of the average wall thickness. The outer diameter of a center part is enlarged to about 110% or more of the average outer diameter, and the wall thickness is thinned to 90% or less of the average wall thickness. The change of the outer diameter and wall thickness from both end parts to the center part is to be smooth. Since the diameter of a single pipe is changed in the longitudinal direction, this single pipe supporting member is provided with strength not less than that of a single pipe supporting member formed of a steel pipe while making most of the merit of weight reduction through the use of aluminium material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe support material used in formwork support work for construction work.

[0002]

2. Description of the Related Art A pipe support material is one of the temporary structures installed in construction work. The pipe support material is used to support the formwork and support work from below, and a compressive load is applied in the axial direction during use. In addition to the screw structure pipe support material whose length can be adjusted by itself, there is a single pipe pipe support material whose length is adjusted using a jack type base metal, which is usually
Outer diameter φ48.6 mm, inner diameter φ43.6 mm, wall thickness t2.
A straight shaped steel tube of 5 mm carbon steel is used.

[0003]

When such a support material is used at a work site, an operator must carry the support material by himself, and it is desirable to reduce the weight of the support material as much as possible. There is. However, steel pipes currently used in single pipes are heavy, and even if the single pipe is shortened in consideration of workability, the number of joint parts will increase, so
Even if the cost is increased and the cross-sectional area is reduced to reduce the weight, there is a problem that the strength is insufficient and the standard is not satisfied.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to provide a lightweight and easy-to-handle aluminum alloy single pipe support material while maintaining strength performance. It is what

That is, according to the present invention, at both ends in the longitudinal direction, the outer diameter is smaller than the average outer diameter, and the wall thickness is thicker than the average wall thickness. Is thicker than the outer diameter of, and thinner than the average thickness,
Further, the aluminum alloy single pipe pipe support material is characterized in that the change in outer diameter and wall thickness from both ends to the center is smooth.

The single pipe support material of the present invention has strength performance equal to or higher than that of a steel pipe used as a standard single pipe, and is naturally lighter than a steel pipe.

When a compressive load is applied to the single pipe pipe support material and the strength limit point is exceeded, buckling occurs near the center of the pipe. The inventors of the present application have found that strength performance can be improved by making this buckling less likely. In order to have the buckling resistance of the extruded aluminum material to the same level as the steel pipe, it is necessary to increase the wall thickness or diameter of the pipe, but if the wall thickness is larger than that of the steel pipe, Since there is no merit of weight reduction, there is no choice but to increase the diameter.

However, if the straight material has a large diameter and thin cross section, the inner diameter of the end portion in the longitudinal direction must be larger than that of the conventional material. Then, a joint metal fitting and a jack type base metal fitting that are conventionally used by inserting a steel pipe into the pipe end cannot be used. Therefore, in the present invention, by changing the diameter of the single pipe in the longitudinal direction, the inner diameter of the pipe end is made equal to that of the conventional steel pipe while keeping the second moment of area of the center where the cross-section buckling is likely to occur large, and the aluminum profile A single-pipe pipe support material that fully utilizes the merit of weight reduction by use.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In consideration of extrudability, workability, strength, etc., the aluminum alloy used in the aluminum alloy single pipe pipe support material of the present invention is JIS A6.
063-T5, JIS A6061-T6 and the like are mentioned, but the invention is not particularly limited thereto.

The greatest feature of the present invention is that the shape of the tube end and the central part in the longitudinal direction is changed, but the outer diameter of the tube end is smaller than the average outer diameter. 90% or less of the average outer diameter is preferable, and the wall thickness of the pipe end portion is thicker than the average wall thickness, and more specifically, 110% or more of the average wall thickness is preferable. Further, the outer diameter of the central portion is thicker than the average outer diameter, specifically, 110% or more of the average outer diameter is preferable, and the wall thickness of the central portion is thinner than the average wall thickness. 90% or less of the wall thickness is preferable.

By making the shape of the single pipe pipe support material as described above, while keeping the inner diameter of the pipe end the same size as that of the conventional steel pipe, the cross section secondary in the center portion where the buckling easily occurs It is possible to increase the moment.
When the ratio of the second moment of area of the center to the second moment of area of the tube end (center / tube end) is 1.2 or more, the buckling strength is equal to or higher than that of the conventional steel pipe. It is desirable that the ratio of the secondary moments be 1.2 or more.

The reason why the change in the outer diameter and the thickness from the both ends to the central part is made smooth is that if it is not smooth, the stress is concentrated at the portion where the cross section changes stepwise and the buckling easily occurs. Because. By the way, as mentioned above, in order to form a shape in which the cross-section changes smoothly in the longitudinal direction, there is a method of expanding the central part by bulge molding from a raw pipe that matches the outer diameter of the pipe end, Although it is possible to reduce the diameter by shrink-molding a raw tube that matches the diameter toward both ends, any method may be used.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments.

The aluminum alloy used in the examples is JI.
SA6063-T5. The above-mentioned molten aluminum alloy was cast by a conventional method to obtain an ingot, which was extruded by a press and then subjected to artificial aging treatment to produce an aluminum alloy pipe. This tube is bulged to expand the central part of the tube,
The single-pipe pipe support material as shown in Fig.

As a conventional example, a straight steel pipe as shown in FIG. 7 was used, and as a comparative example, a straight aluminum pipe as shown in FIGS. 4 to 6 was used. No.1-7
As a compression test, the tube of No. 2 was subjected to a knife edge push test at both ends shown in FIG. Table 1 shows the results. Table 1 also shows the weight reduction rate and whether or not conventional connecting parts can be used.

[0016]

[Table 1]

Inventive Examples Nos. 1 and 2 each have a sectional second moment ratio of 1.2 or more, a compressive strength larger than that of the steel pipe, can use conventional connecting parts, and realize weight reduction. There is. On the other hand, in Comparative Example No. 4, the straight tube was thinned to be thin, and thus the compressive strength was insufficient. In No. 5, the straight tube was made to be large-diameter and thickened, the compressive strength was Although it is superior to the steel pipe, the weight becomes heavier than the steel pipe, and the weight reduction which is the object of the present invention is not realized.

[0018]

As described above in detail, according to the present invention, while having a compressive strength equal to or higher than that of the conventional single-pipe support material for steel pipe, it is lightweight and has good workability, and yet it is conventional. The above-mentioned connection parts can be used as they are, and industrially remarkable effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an aluminum alloy single pipe pipe support material of the present invention.

FIG. 2 is a perspective view showing an aluminum alloy single pipe support material of the present invention.

FIG. 3 is a perspective view showing an aluminum alloy single pipe support material of the present invention.

FIG. 4 is a perspective view showing a straight-shaped aluminum alloy single pipe support member.

FIG. 5 is a perspective view showing a straight-shaped aluminum alloy single pipe support member.

FIG. 6 is a perspective view showing a straight-shaped aluminum alloy single pipe support member.

FIG. 7 is a perspective view showing a conventional steel single pipe support member.

FIG. 8 is an explanatory view showing a both-end knife edge pushing test which is a compression test method.

Claims (1)

[Claims] 1. At both ends in the longitudinal direction, the outer diameter is smaller than the average outer diameter, and the wall thickness is thicker than the average wall thickness, and the outer diameter is larger than the average outer diameter in the central portion in the longitudinal direction. An aluminum alloy single pipe support material that is thicker and thinner than the average wall thickness, and that the change in outer diameter and wall thickness from both ends to the center is smooth.