JP2019105108A - Aluminum single pipe - Google Patents

Abstract

To improve a point that a conventional single pipe easily rolls in a circumferential direction since an outer shape is a circle and that single pipes with a swollen central part in an axial direction do not have a stable packing style and be easily collapsed.SOLUTION: An aluminum single pipe 1 of this invention is made of aluminum, has a same size as a diameter specified outer diameter of a carbon steel pipe with a general structure specified in JISG3444, and includes a flat portion 2 formed by removing a wall thickness with an arc-shaped cross section specified as a chord length of 10 to 50% of an outer diameter in an axial direction in at least one position of an outer periphery.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an aluminum single pipe which is lighter than steel and is easy to handle by preventing rolling in the circumferential direction.

  Materials used in construction and construction work include those called "single pipes" (or "pipes"). A single pipe is mainly used to assemble a scaffold in a construction site, and a general structure carbon steel pipe according to JIS G 3444 is adopted, the diameter standard is set to 48.6 mm in outer diameter, and the length is in a range of 360 to 6000 mm. Exists. The reason why there is no type exceeding 6000 mm is that when the length is increased, distortion occurs with time by weight when standing up.

  A single pipe is a basic material that is generally used, that the basic material is rich in variations of other materials, and that a certain strength can be grasped and guaranteed. Therefore, although a considerable number is used in most sites, it is made of steel, so it is for workers to handle to move a large number of single pipes or build a scaffold etc. by transportation to the site etc. It was hard work.

  Therefore, in Patent Document 1, the outer diameter is smaller than the average outer diameter at both end portions in the longitudinal direction and the thickness is larger than the average thickness at the central portion in the longitudinal direction. We propose a single aluminum tube that is thicker than the diameter, thinner than the average thickness, and smooth in outer diameter and thickness variation from both ends to the center, While maintaining it, a lightweight, easy-to-use single tube is realized.

  However, Patent Document 1 has a problem that it is easy to roll in the circumferential direction because the cross section is circular as in the case of a conventional single steel tube, and further, for example, because the central portion in the axial direction bulges. There was a problem that the packing style when transporting a large number of books was unstable and it was easy for the cargo to collapse.

JP-A-9-158500

  The problem to be solved is that, in the conventional single tube, the outer shape is circular, so it is easy to roll in the circumferential direction. In Patent Document 1, for example, a large number of tubes are transported because the central portion in the axial direction bulges. It is a point that the packing style at the time is unstable and it is easy to collapse.

  The aluminum single pipe of the present invention is made of aluminum and has the same dimensions as the diameter standard outer diameter of a general structure carbon steel pipe standardized to JIS G 3444, and at least one place on the outer periphery at 10 to 50% of the outer diameter It has the flat part which removed the thickness of a section circular arc shape specified by the chord length of a shaft in the direction of an axis.

  The aluminum single pipe of the present invention can be made lighter as compared with a conventional steel single pipe of the same outer diameter by using aluminum as the material. Further, according to the present invention, rolling in the circumferential direction is suppressed by having a flat portion at at least one place on the outer periphery. Furthermore, according to the present invention, since the cross-sectional shape is constant in the axial direction, the strength does not differ at the place where it is cut as in Patent Document 1, and the package appearance is stable even when transporting a plurality of pieces together. Also has the advantage of being less likely to cause a load collapse.

It is an aluminum single pipe in the Example of this invention, (a) is an end elevation, (b) is a perspective view. It is an end elevation of an aluminum single pipe in another example of the present invention. It is an end elevation of the aluminum single pipe | tube in the further another Example of this invention.

  In the present invention, in the prior art, because the outer shape is circular, it is easy to roll in the circumferential direction, and in Patent Document 1, the central part in the axial direction is bulging. Is not stable, and the flat part where the thickness of circular arc shaped cross section defined by the chord length of 10 to 50% with respect to the outer diameter is removed in the axial direction at the point where the load collapses easily It improved by having. Moreover, about the point where the conventional steel single pipe is heavy, the weight was reduced by using aluminum as the material.

  The aluminum single pipe of the present invention is made of aluminum but has the same dimensions as the diameter standard outer diameter of a general structure carbon steel pipe standardized according to JIS G 3444, and has the required rigidity and is lightweight An aluminum alloy may be used if it meets the requirements. And, the reason for adopting aluminum is that it can be reduced in weight and relatively inexpensive.

  The aluminum single pipe of the present invention is based on the diameter standard outer diameter (for example, 48.6 mm) of a general structure carbon steel pipe standardized according to JIS G 3444, and the outer diameter size is the same as this (in this case 48.6 mm) And The reason is that other conventional materials such as clamps can be used as they are.

  And, in the aluminum single pipe of the present invention, when the flat portion has a thickness of an arc-shaped cross section defined by a chord length shorter than 10% with respect to the outer diameter, the light weight effect and rolling in the circumferential direction In the case where the thickness of the arc-shaped cross section defined by the chord length longer than 50% with respect to the outer diameter is deleted, the tube becomes a square tube instead of a single tube, and the conventional one for single tube There is a possibility that other materials can not be used.

  Furthermore, in the above-described configuration, the aluminum single pipe of the present invention has a maximum bending moment Mmax which falls within -50 kN · cm, based on the diameter standard outer diameter of the general structure carbon steel pipe standardized in JIS G3444. Specifically, the number of flat portions (2 to 4), the amount of deletion of the thickness of the flat portions, and the inner diameter (thickness of layers other than flat portions) are adjusted so as to obtain the area.

  By doing this, the maximum in the same outer diameter type as the general structure carbon steel pipe is achieved without impairing the effects of the above-described weight reduction, circumferential rolling suppression, packing shape stability, and flexibility of use of other materials. Allowable strength of bending moment can be maintained.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The aluminum single pipe 1 of the present invention is made of aluminum, and has the same outside diameter as the diameter standard outside diameter 48.6 mm of a single pipe of STK 500, for example, a general structure carbon steel pipe standardized to JIS G3444. In the cross section defined by the chord length of 38% (Fig. 1), 10% (Fig. 2) and 50% (Fig. 3) with respect to the outer diameter at four points (two pairs) of diametrically opposed positions separated by 90 °. It has the flat part 2 which removed circular arc-like thickness in the axial direction.

  In the present embodiment, the maximum bending moment Mmax with respect to STK 500 falls within -50 kN cm when the cross-sectional area in the state of having four flat portions 2 (two pairs) at diametrically opposed positions is used as a reference. Thus, the inner diameter was fixed to, for example, 39.0 mm.

  Hereafter, the result of having compared STK500 and the specification of aluminum single pipe 1 of this invention, a weight, and the largest bending moment Mmax is demonstrated. The aluminum single pipe 1 of the present invention used in the following comparison was prepared from 6061 standardized by JISH 4080.

(STK500)
Outer diameter: 48.6 mm
Flat part: None Reference strength: 350 N / mm ²
Cross-sectional area: 348.3 mm ²
Section modulus: 3830 mm ³
Weight: 2.74 kg / m
Maximum bending moment (Mmax): 134.0 kN cm

(Figure 1: The flat part 2 has a chord length of 38% of the outer diameter)
Outer diameter: 48.6 mm
Flat part: With (4 places)
Reference strength: 230 N / mm ²
Cross-sectional area: 572.7 mm ²
Section modulus: 6026.1 mm ³
Weight: 1.56 kg / m
Maximum bending moment (Mmax): 138.6 kN cm
Mmax difference with STK 500: +4.6 kN. cm
・ Weight difference with STK 500: -1.18 kg / m

(Figure 2: Flat portion 2 has a chord length of 10% of the outer diameter)
Outer diameter: 48.6 mm
Flat part: With (4 places)
Reference strength: 230 N / mm ²
Cross-sectional area: 320.0 mm ²
Section modulus: 3800 mm ³
Weight: 0.86 kg / m
Maximum bending moment (Mmax): 87.4 kN cm
· Mmax difference with STK 500: -46.6 kN · cm
・ Weight difference with STK 500: -1.88 kg / m

(Figure 3: The flat part 2 has a chord length of 50% of the outer diameter)
Outer diameter: 48.6 mm
Flat part: With (4 places)
Reference strength: 230 N / mm ²
Cross sectional area: 820.0 mm ²
Section modulus: 8300 mm ³
Weight: 2.21 kg / m
Maximum bending moment (Mmax): 190.9 kN cm
・ Mmax difference with STK500: +56.8 kN · cm
-Weight difference with STK 500: -0.53 kg / m

  As described above, the aluminum single pipe 1 according to the present invention is made of aluminum and the partial thickness on the outer diameter side is removed, so that weight reduction is achieved, and the flat portion 2 is provided. It can prevent rolling in the circumferential direction. In addition, since the flat portion 2 is uniformly continuous in the axial direction, the package shape in the case of collectively carrying a plurality of pieces is stabilized, and the occurrence of a load collapse is suppressed.

  Furthermore, the single-tube aluminum tube 1 of the present invention has a cross-sectional area in which the difference in maximum bending moment Mmax is within −50 kN · cm or more based on the diameter standard outer diameter of the general structure carbon steel pipe standardized in JIS G3444. Thus, by adjusting the number of flat portions 2, the chord length, and the inner diameter, it is possible to maintain the strength as well as the above-mentioned effects similar to a single steel pipe.

1 Aluminum single pipe 2 Flat part

Claims (2)

  A single pipe used in construction and construction sites, made of aluminum and of the same size as the diameter standard outer diameter of a general structure carbon steel pipe standardized according to JIS G 3444, at least at one location on the outer periphery, 10 against the outer diameter An aluminum single pipe characterized by having a flat portion in the axial direction from which a thickness of a cross-sectional arc shape defined by a chord length of -50% is removed in the axial direction.   The aluminum according to claim 1, characterized in that the difference in maximum bending moment Mmax based on the diameter standard outer diameter of the general structure carbon steel pipe standardized in JIS G3444 is within -50 kN · cm or more. Single tube made.

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