Rolled tube fabrication method

Abstract

A rolled tube fabrication method of making a rolled tube by: cutting a surface-treated metal sheet material subject to the desired size, and then bending the two opposite lateral side edges of the surface-treated metal sheet material into a respective hooked portion, and then forcing the two hooked portions of the surface-treated metal sheet material to hook each other, and then roller-ramming the hooked area of the surface-treated metal sheet material so as to obtain a finished rolled tube.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to the fabrication of rolled tubes and, more particularly, to a simple, economic rolled tube fabrication method, which eliminates the process of welding.

[0003] 2. Description of the Related Art

[0004] Conventionally, a rolled tube is made, as shown in FIGS. 1 and 2, by rolling up a metal sheet material A into a tubular shape, and then sealing the abutted edges of the tubular metal sheet material with a welding apparatus, and then adhering the surface of the tube with a layer of covering or spray-painting/electroplating the surface of the tube with a layer of coating. This rolled tube fabrication method has numerous drawbacks as follows:

[0005] 1. Due to complicated processing procedure, the manufacturing cost of this method is high.

[0006] 2. Because the abutted edges of the tubular metal sheet material are welded together, the welded area must be cleaned or polished before the covering layer bonding, spray-painting or electroplating process, and the roundness control of the tube is difficult to maintain.

[0007] 3. The surface treatment can only be employed to the outer surface of the tube, and the inner surface of the tube cannot be well treated with a surface treatment.

[0008] 4. Because a welding process is necessary, the selected metal sheet material must have a certain wall thickness. If a thin metal sheet material is used, the flame of the welding apparatus used may cut through the wall of the metal sheet material during welding. Further, when a thin metal sheet material is used and rolled into a tube, the rolled tube can easily be deformed.

SUMMARY OF THE INVENTION

[0009] The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a rolled tube fabrication method, which eliminates the aforesaid drawbacks. It is another object of the present invention to provide a rolled tube fabrication method, which is practical and economic for making rolled tubes for use in blind fabrication. According to one aspect of the present invention, a surface-treated metal sheet material is used and cut subject to the desired size, and then the two distal side edges of the surface-treated metal sheet material are bent into a respective hooked portion, and then the two hooked portions of the surface-treated metal sheet material are respectively coated with a layer of glue and then hooked up, and then the hooked area of the surface-treated metal sheet material is roller-rammed, and thus a finished rolled tube is obtained. According to another aspect of the present invention, a bonding agent is applied to gaps in the hooked area before roller ramming. According to still another aspect of the present invention, the roller-rammed area of the rolled tube forms a rib that enhances the structural strength of the rolled tube.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a cross-sectional view of a rolled tube made according to the prior art.

[0011] FIG. 2 is a block diagram showing a rolled tube fabrication flow according to the prior art.

[0012] FIG. 3 is a cross-sectional view, hooked portions of the metal sheet material hooked together according to the present invention.

[0013] FIG. 4 is a block diagram showing a rolled tube fabrication flow according to the present invention.

[0014] FIG. 5A is a cross-sectional view of a finished rolled tube made according to the present invention.

[0015] FIG. 5B is an enlarged view of a part of FIG. 5A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] Referring to FIGS. 3, 4, 5A and 5B, a metal sheet material 10 is selected, and then a surface treatment is employed to the metal sheet material 10. The surface treatment can be any of a variety of conventional methods. For example, the two sides of the selected metal sheet material can be respectively bonded with a respective layer of covering material, spray-painted with a respective layer of coating, or electroplated. The surface treated metal sheet material is then cut subject to the desired size, and then the two distal side edges of the surface treated metal sheet material are respectively turned downwards and then backwards, or upwards and then backwards, forming a respective hooked portion, and then the hooked portions are respectively coated with a layer of glue, and then the surface treated metal sheet material is rolled into the shape of a tube for enabling the two hooked portions to be hooked together. Thus, a semi-finished tube is obtained (see FIG. 3). Thereafter, the connected hooked portions of the semi-finished tube are roller-rammed into a flat structure (see FIGS. 5A and 5B).

[0017] While only one embodiment of the present invention has been shown and described, it will be understood that various modifications could be made thereunto without departing from the spirit and scope of the invention disclosed.

Claims

What the invention claimed is:

1. A rolled tube fabrication method comprising the steps of a) selecting a surface-treated metal sheet material and cutting the selected surface-treated metal sheet material subject to a predetermined size; b) bending the selected surface-treated metal sheet material to form two hooked portions at two opposite lateral sides of the selected surface-treated metal sheet material; c) forcing the hooked portions of the selected surface-treated metal sheet material to hook up each other; and d) roller-ramming the hooked area of the hooked portions of the selected surface-treated metal sheet material.

2. The rolled tube fabrication method as claimed in claim 1, further comprising a sub-step of covering said hooked portions with a layer of glue before forcing said hooked portions to hook up each other.