JP7125081B2 - Aluminum single tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aluminum single pipe which is lighter than steel, prevents rolling in the circumferential direction, and is easy to handle.

2. Description of the Related Art There is a material called a “single pipe” (or “pipe”) used in construction and construction work. Single pipes are mainly used for scaffolding at construction sites, and general structural carbon steel pipes according to JISG3444 are adopted. exist. The reason why there are no types exceeding 6000 mm is that when the length is increased, distortion occurs over time due to its own weight when it is erected (standing).

A single pipe is a basic material that is commonly used, and because it is a basic material, there are many variations of other materials, and a certain strength is understood and guaranteed. For this reason, a considerable number of pipes are used at most sites, but since they are made of steel, it is difficult for workers to move a large number of single pipes during transportation to the site, or to handle them to build scaffolding. It was hard work.

Therefore, in Patent Document 1, at both ends in the longitudinal direction, the outer diameter is thinner than the average outer diameter and the wall thickness is thicker than the average wall thickness, and at the central portion in the longitudinal direction, the outer diameter is the average outer diameter. We propose an aluminum single tube that is thicker than the diameter, thinner than the average wall thickness, and has a smooth change in outer diameter and wall thickness from both ends to the center, and achieves strength performance. A lightweight and easy-to-handle single pipe is realized while maintaining the same.

However, Patent Document 1 has the problem that it easily rolls in the circumferential direction because it has a circular cross section, as with conventional steel single pipes, and furthermore, because the central portion in the axial direction bulges, for example, There was a problem that the packing style was not stable when transporting a large number of books, and the cargo easily collapsed.

JP-A-9-158500

The problem to be solved is that conventional single pipes tend to roll in the circumferential direction because they have a circular outer shape, and in Patent Document 1, the central portion in the axial direction bulges, so it is difficult to convey, for example, a large number of pipes. The point is that the shape of the cargo is not stable when it is packed, and it is easy for the cargo to collapse.

The aluminum single pipe of the present invention is a single pipe used at building and construction sites, is made of aluminum, has the same diameter as the standard outer diameter of a general structural carbon steel pipe standardized by JIS G3444, and is axially It has a constant cross-sectional shape, and has four flat portions in the axial direction with the thickness of the arc-shaped cross-section removed at 90° intervals on the outer circumference of the diametrically opposed position, and the outer diameter of the flat portion in the arc-shaped cross-section When adjusting the thickness reduction amount in the chord length range of 10 to 50% and the thickness other than the flat part, and using the diameter standard outer diameter of general structural carbon steel pipe standardized by JISG3444 as a standard As a cross-sectional area where the difference in the maximum bending moment Mmax is -50 kN cm or more, the strength within the allowable range for use with the same outer diameter type as the general structural carbon steel pipe is maintained, and the same outside as the general structural carbon steel pipe. It is characterized by being lighter than the diameter type.

The aluminum single pipe of the present invention is made of aluminum, so that it is lighter than conventional steel single pipes of the same size as the diameter standard outer diameter type of general structural carbon steel pipes standardized by JISG3444. In addition, it is possible to maintain the strength within the allowable range for the maximum bending moment in the same dimension as the diameter standard outer diameter type of general structure carbon steel pipe standardized by JISG3444. Further, in the present invention, rolling in the circumferential direction is suppressed by having a flat portion on at least one portion of the outer periphery. Furthermore, in the present invention, since the cross-sectional shape is constant in the axial direction, there is no difference in strength at the cutting point as in Patent Document 1, and the packing style is stable even when multiple items are transported together. It also has the advantage that cargo collapse is less likely to occur.

BRIEF DESCRIPTION OF THE DRAWINGS It is an aluminum single tube in the Example of this invention, (a) is an end view, (b) is a perspective view. FIG. 4 is an end view of an aluminum single tube in another embodiment of the present invention; FIG. 11 is an end view of an aluminum single tube in still another embodiment of the present invention;

In the present invention, the material is aluminum, the diameter is the same as the standard outer diameter of a general structural carbon steel pipe standardized by JISG3444, the cross-sectional shape is constant in the axial direction, and the four locations are spaced apart by 90° on the outer circumference of the diameter facing position. has a flat portion with an arcuate cross-sectional thickness removed in the axial direction, and the amount of thickness reduction in the chord length range of 10 to 50% of the outer diameter of the arcuate cross-section of the flat portion, the flat The cross-sectional area where the difference in the maximum bending moment Mmax is -50 kN cm or more when the diameter of the general structure carbon steel pipe standardized by JIS G3444 is used as the standard outer diameter by adjusting the wall thickness other than the part. , while maintaining the strength within the permissible range for use in the same outer diameter type as the general structure carbon steel pipe, the weight is made lighter than the same outer diameter type as the general structure carbon steel pipe.

The aluminum single pipe of the present invention is made of aluminum, but has the same diameter and standard outer diameter as the general structural carbon steel pipe standardized by JISG3444, has the required rigidity, and is lightweight. An aluminum alloy may be used as long as it satisfies the following conditions. The reason for using aluminum is, first, that it can be made lighter and is relatively inexpensive.

In addition, the aluminum single pipe of the present invention is based on the standard outer diameter (for example, 48.6 mm) of the general structure carbon steel pipe standardized by JISG3444, and the outer diameter dimension is the same as this (48.6 mm in this case). and The reason for this is that other conventional materials such as clamps can still be used.

In the aluminum single tube of the present invention, when the thickness of the flat portion having an arcuate cross section defined by a chord length shorter than 10% of the outer diameter is removed, the weight effect and rolling in the circumferential direction are reduced. On the other hand, if the wall thickness of the arc-shaped cross section defined by the chord length longer than 50% of the outer diameter is removed, it becomes a square tube instead of a single tube. Other materials may become unusable.

Furthermore, in the aluminum single pipe of the present invention, in the above configuration, the maximum bending moment Mmax when the diameter standard outer diameter of a general structural carbon steel pipe standardized by JISG3444 is used as a reference is within -50 kN cm. More specifically, the number of flat portions (2 to 4), the amount of thickness reduction for the flat portions, and the inner diameter (thickness of portions other than the flat portions) are adjusted so as to obtain the area.

By doing this, we can achieve the maximum weight of carbon steel pipes with the same outer diameter as general structural carbon steel pipes without impairing the effects of weight reduction, suppression of rolling in the circumferential direction, stability of packing, and flexibility in the use of other materials. It is possible to maintain strength within the allowable range for bending moment.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. The aluminum single tube 1 of the present invention is made of aluminum and has the same outer diameter as the standard outer diameter of 48.6 mm for a single tube of STK500, which is a general structural carbon steel tube standardized by JIS G3444, for example, in this embodiment. Sections defined by chord lengths of 38% (Fig. 1), 10% (Fig. 2), and 50% (Fig. 3) of the outer diameter at four points (two pairs) diametrically opposed positions separated by 90°. It has an arc-shaped flat portion 2 with the thickness removed in the axial direction.

In this embodiment, the maximum bending moment Mmax is within -50 kN cm when the cross-sectional area having four (two pairs) of flat portions 2 at diametrically opposed positions is based on STK500. I made it

The results of comparing STK500 and the aluminum single tube 1 of the present invention in terms of specifications, weight, and maximum bending moment Mmax will be described below. The aluminum single tube 1 of the present invention used in the following comparison was made from 6061 standardized by JISH4080.

(STK500)
Outer diameter: 48.6mm
Flat part: None Reference strength: 350 N/mm ²
Cross-sectional area: ^348.3mm2
Section modulus: ^3830mm3
Weight: 2.74kg/m
Maximum bending moment (Mmax): 134.0 kN cm

(Figure 1: Flat part 2 has a chord length that is 38% of the outer diameter)
Outer diameter: 48.6mm
Flat part: Yes (4 places)
Reference strength: 230 N/mm ²
Cross-sectional area: ^572.7mm2
Section modulus: ^6026.1mm3
Weight: 1.56kg/m
Maximum bending moment (Mmax): 138.6 kN cm
・Mmax difference from STK500: +4.6 kN. cm
・Weight difference from STK500: -1.18kg/m

(Figure 2: Flat part 2 has a chord length of 10% of the outer diameter)
Outer diameter: 48.6mm
Flat part: Yes (4 places)
Reference strength: 230 N/mm ²
Cross ^- sectional area: 659.9mm2
Section modulus: ^3800mm3
Weight: 0.86kg/m
Maximum bending moment (Mmax): 87.4 kN cm
・Mmax difference from STK500: -46.6kN・cm
・Weight difference from STK500: -1.88kg/m

(Figure 3: Flat part 2 has a chord length that is 50% of the outer diameter)
Outer diameter: 48.6mm
Flat part: Yes (4 places)
Reference strength: 230 N/mm ²
Cross-sectional area: ^820.0mm2
Section modulus: ^8300mm3
Weight: 2.21kg/m
Maximum bending moment (Mmax): 190.9kN cm
・Mmax difference from STK500: +56.8kN・cm
・Weight difference from STK500: -0.53kg/m

As described above, the aluminum single tube 1 of the present invention is made of aluminum and has a reduced thickness by partially removing the wall thickness on the outer diameter side. Rolling in the circumferential direction can be prevented. In addition, since the flat portion 2 is uniformly continuous in the axial direction, the packing style is stable when a plurality of pieces are transported together, and collapse of cargo is suppressed.

Furthermore, the aluminum single pipe 1 of the present invention has a cross-sectional area where the difference in the maximum bending moment Mmax is -50 kN cm or more when the diameter standard outer diameter of the general structure carbon steel pipe standardized by JIS G3444 is used as a reference. By adjusting the number of flat portions 2, the length of the chord, and the inner diameter, it is possible to maintain the above effect and the strength of a single pipe made of steel.

1 Aluminum single tube 2 Flat part

Claims (1)

A single pipe used at building and construction sites, the material is aluminum, the diameter is the same as the standard outer diameter of the general structure carbon steel pipe standardized by JISG3444, the cross-sectional shape is constant in the axial direction, and the diameter is opposite. It has flat portions in the axial direction where the thickness is removed and has an arcuate cross section at four locations spaced apart by 90° on the outer circumference, and the chord length is within a range of 10 to 50% of the outer diameter of the arcuate cross section of the flat portions. The difference in the maximum bending moment Mmax is -50 kN when the standard outside diameter of the general structure carbon steel pipe standardized by JISG3444 is used as the standard by adjusting the thickness reduction amount and the thickness other than the flat part.・It is characterized by maintaining the strength within the allowable range for use with the same outer diameter type as the general structural carbon steel pipe, and making it lighter than the general structural carbon steel pipe with the same outer diameter type. A single tube made of aluminum.

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