JPH01278911A - Manufacture of tapered tube - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost and to improve the productivity by folding both side ends of a metal strip whose width gradually decreases and winding the strip into a spiral shape and caulking the side ends. CONSTITUTION:A metal strip 10 is cut to form a stock 1 whose width gradually decreases in the longitudinal direction and the stock 1 is wound into a coil and then is rewound by a required length. Then, both side ends of the stock 1 are folded by a seaming machine 3 to form folded parts 12, 13 and the parts 12, 13 are joined together, and the stock 1 is spirally wound. The joined part of the parts 12, 13 is caulked by a caulking roll 6 synchronously driven with a forming roll 5. A space required by a device is reduced and complex electronic control is eliminated. By that, the manufacturing cost is reduced, the working speed is increased by elimination of welding, and the productivity of products is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of manufacturing a tapered pipe by spirally winding a metal strip material.

(b) Prior art In general, for structures that stand perpendicular to the horizon or cantilevered strength members, it is more rational to have a taper (part of a cone), both aesthetically and in terms of the strength of the member. One thing is well known. However, it has been difficult to industrially produce tapered shapes in large quantities at low cost compared to parallel cylindrical shapes.

Conventionally, tapered tubes used for telephone poles, lighting poles, flagpoles, signposts, etc. have been manufactured by the UO press method, swaging method, Birgarol method, or by combining short tubes using a roll bender.

However, although the thickness of the material was approximately 2.3 to 4.5 tram, the equipment was large-scale and productivity was low. Moreover, when the product dimensions change, it becomes necessary to change tools and jigs, making it unsuitable for small-scale production and expensive.

In order to improve this, a method has been proposed in which the material is wound spirally around a tapered mandrel and welded (Japanese Unexamined Patent Publication No.
2-77117]. However, this method required a mandrel as a main pipe, and caused thermal distortion and swelling due to welding, and could not meet the aesthetic demands of society.

(c) Problems to be Solved by the Invention The problem to be solved by the present invention is to provide a method for manufacturing a metal tapered pipe with high strength using inexpensive equipment without wasting material.

B) Means for Solving the Problem The method for manufacturing a tapered pipe of the present invention includes using a metal strip whose width gradually decreases along the longitudinal direction as a material, and bending the material along both longitudinal edges. The above-mentioned problems are solved by forming a portion of the material, spirally winding the material while connecting the bent portions of the material, and caulking the connecting portions together.

(e) Implementation example The method of the present invention will be explained with reference to FIG.

First, a metal strip whose width gradually decreases along the longitudinal direction is used as material 1 (A). A metal strip 10, such as a copper strip, is cut by a rotating knife, plasma, or the like.

After cutting, each material 1 is wound into a coil 11 (B).

Next, the coil 11 is placed on the coil lamp 2 and wound back to the required length (C).

Bent portions 12 are formed along both longitudinal edges of the rewound material 1.
．． 13 (D). This bent portion 12.13 is
It is formed by a seam folding machine 6 (FIG. 2).

The material 1 is wound spirally while connecting the bent portions of the material 1 to each other (E). The charging angle of the material 1 is adjusted by a charging angle adjuster 4 (FIG. 2). Material 1 is
It is wound spirally by forming rolls 5.

Caulk the connecting portions of bent portions 12 and 13 together (F). This caulking is performed by a caulking roll 6. The caulking roll 6 is driven in synchronization with the forming roll 5.

The formed tapered tube 20 is cut with both ends aligned with the tube axis to become a product (G).

Tapered tubes of the following sizes were actually manufactured using the method of the present invention. We were able to produce 60 pieces per hour. 5
This is a productivity equivalent to 6-6 times that of the conventional method.

tapered tube size Root diameter: 3001111 Tip diameter: 150 degrees Length: 81rL Steel plate thickness: 1.2+m Caulking protrusion: Extrudes on the inner surface of the tube, and the outer surface of the tube is smooth.

(to) Effect According to the method of the present invention, the following effects can be obtained.

■ The degree of taper is determined by the degree of change in the band width of the material, and once the tip diameter is determined, the feeding angle, forming roll, and product table can be automatically set, so complex electronic control is not required.

■ It is compact, requiring only 1/6 to 1/10 the space compared to conventional equipment.

■ Since no welding is involved, there is no need to worry about distortion due to heat effects, no welding cracks, and pre-surface-treated metal strips can be used, making it easier to apply heat than welding. There are also fewer speed restrictions.

■ Due to the seam-folding and caulking process, it has a flat strength that is more than 1.5 times that of a flat cylindrical tube of the same wall thickness, even though it uses thin-walled material, so it can be used as a pole as well. .

■ Processing using rotation, known as spiral winding, enables high-speed processing and high productivity, which is more than three times faster than conventional manufacturing methods.

■ Due to the size of the product, there are almost no replacement jigs and tools.

By reversing the upper and lower sides of the tube end folding roll, the caulking convex portion can be brought to both the inner and outer surfaces of the tube.

■ Metal strips can be cut rationally, so no material is wasted.

[Brief explanation of the drawing]

W, Figure 1 is an explanatory diagram of the steps of the method of the present invention. FIG. 2 is an explanatory diagram of an apparatus for carrying out the method of the present invention. 1: Material 2: Coil lamp 3: Edge folding machine 4: Feeding angle adjuster 5: Forming roll
6: Clamping roll 11: Coil 10: Metal band 20: Tapered tube.

Claims (1)

[Claims] The material is a metal strip whose width gradually decreases along the longitudinal direction, the bent portions are formed along both edges in the longitudinal direction of the material, and the bent portions of the material are connected to each other. A method for manufacturing a tapered pipe, which comprises spirally winding a material and caulking the connecting portions together.