JPS63203229A - Manufacture of hollow pin - Google Patents

Abstract

PURPOSE:To well form a long hollow pin by subjecting the stainless steel pipe in specific length whose one end is squeezed in a specific length in the diameter direction to a die charging in a projection shape and after forming it by its sinking in larger state than the pipe diameter by a punch, performing drawing on the pipe diameter. CONSTITUTION:The stainless steel pipe 1 cut in a specific length and one part end of the other pipes are squeezed in the diameter direction in the length of about 5-12mm. This squeezed part 2 is charged in a projection shape from the die tip and subjected to cold heading by a punch to the sink forming part 3 having larger diameter than the die hole diameter. Thereafter, this sink forming part 3 is subjected to drawing same as the pipe diameter by a die and punch. The stainless pipe 1, etc., being hard to work are subjected to drawing by smoothing the material flow at the sink forming stage and pushing in without any crack and breakdown. Consequently even a deep holed hollow pin can well be formed in a product.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an anchor bottle, a hollow bottle for the purpose of weight reduction, and a method for manufacturing a hollow bottle by enclosing a different wire material or the like in the internal cavity of the bottle.

Conventional Technology When producing anchor pins or hollow bottles for the purpose of weight reduction, conventionally, a solid wire was used as a material to be formed into a pin, and then holes were drilled into the pin.

There were also cases where the head was molded using a parf or tube as it was, and the lower end was threaded.

Problems to be Solved by the Invention In the conventional example, when drilling a hole from a solid object, if it is a high tensile material such as stainless steel (for example, 5t JS304), the depth is about 15 to 20 times the hole diameter. If the hole exceeds this point, it is impossible even for a skilled worker to drill the hole, and the hole may become bent, the drill may become worn out, or breakage may occur, and even if it is possible to successfully drill the hole, it will take a long time and be costly. There were some drawbacks, such as not being able to meet the demand, and not being suitable for mass production.

Also, even when using hollow materials such as pipes and pipes,
For high-tensile materials such as stainless steel (5US304 as mentioned above), it has been extremely difficult to forge the ends and close the hollow portions (solid portions).

The present invention aims to solve the above-mentioned conventional problems and to provide a method for manufacturing a hollow pin made of a pipe or pipe made of a high tensile strength material such as a stainless steel pipe.

Means for Solving the Problems In order to achieve the above object, the present invention includes a first step of diametrically crushing one end of a stainless steel pipe or other pipe cut to a predetermined length to a length of about 5 to 12 cm; The second step is to load the crushed portion so that it slightly protrudes from the tip of the die, and use a punch to form the depressed portion into a state larger than the outer diameter of the tube. The method for manufacturing a hollow pin includes a third step of drawing.

In the first step of the present invention, the cut end of the tube is crushed in the diametrical direction to a length of about 5 to 12+ am, and then the crushed portion is once depressed to a diameter larger than the outside diameter of the tube. After the second molding step, the depressed molded portion is drawn to have the same diameter as the outside diameter of the tube in the third step. By crushing the laid end in this way, even with high-tensile materials such as stainless steel, material flows smoothly during the next depression molding process, making it easy to press the end and preventing cracks and breakage. It is now possible to perform heading processing that does not occur.

The three processes of crushing, depression molding, and drawing can all be performed in the heading process, and even with materials such as stainless steel, the crushed part collapses into the hollow part of the tube as if to cover it, creating a shape in one direction. It has the characteristic that bending and unbalanced buckling phenomena do not occur.

Example material Stainless steel pipe (+) Hole diameter 3.1mm Length 97mm Outside diameter 6mar is used, and one end is 6H crushed part (2
) was first formed using a die and a punch to form a concave molded part (3) with a length of 7 mm and an outer diameter of 8 mm (Figure 1 C, 2), and then a die and a punch were used By using a punch and a punch to form a drawn part (4) to an outer diameter of 6mm (Fig. 1 E and F), a hollow pin (5) with a length of 83mm and a length of the end molded part of 5mm is formed. I got it. After that, the head of the hollow pin (6) was pressed into a product (7) with a neck length of 80+++a (
(See Figure 1 G, H, Figure 2 A-2).

As seen in Example L, hollow stainless steel pins with a neck length of 80 mm or more were easily and beautifully formed.

In particular, the compressed part in the first step can be easily formed by pressing with a normal die and punch if a length of about 5 to 12 mm is used, and the depressed molded part in the second step also allows the material to flow smoothly. A product with no cracks or damage was obtained. After drawing, it was found that it was easy to thread this part or cut it from the center.

Effects of the Invention In the present invention, all steps from the first step to the third step can be performed by heading, and even for high-tensile materials such as stainless steel pipes, the ends can be pressed without causing cracks or damage to the material. Can be done. Therefore, even a long hollow pin with a neck length of 80IIIn or more, which was considered impossible in the past, can now be produced extremely quickly and in large quantities because the end can be easily machined. In addition, conventional processing tools such as dies and punches can be used as they are, making them durable for long-term use.

The end of the steel pipe is about 5 to 12 mm long, and the solid part is pressed into a beautiful state with no cracks or the like for smooth material flow, and allows for easy post-processing such as thread cutting. Become,
This is a revolutionary method for manufacturing hollow pins that have excellent strength and can be used for long periods of time. As anchor pins and hollow pins, long ones with a neck length of 8C1+m or more, which was previously unthinkable with stainless steel, can be obtained in large quantities in a short time, and the length can be increased by sealing other sticky wires into the hollow cavity. It has great effects, such as being able to be applied to the manufacture of strong composite pins that do not buckle.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing the manufacturing process of the present invention, and FIG. 2 is a sectional view of the manufacturing process of a product with a molded head and the product.

Claims (1)

[Claims] (1) The first step is to crush one end of a stainless steel pipe or other pipe cut to a predetermined length in the diametrical direction to a length of about 5 to 12 mm, and then load the crushed part so that it slightly protrudes from the tip of the die, and then press the punch. A second step of forming the recess into a state larger than the outer diameter of the tube using a die, and a third step of drawing the recess formed portion to the same outer diameter as the tube using a die and a punch. Method for manufacturing hollow pins.