JPH03135B2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for manufacturing an anchor bolt.

<Prior art> This type of anchor bolt, as shown in Fig. 6,
A shaft hole 41 and a shaft hole 41 are provided at the center of the axis of the bolt body 4.
A tapered hole 42 is formed at the tip of the tapered hole 42.
Correspondingly, an uneven strip 43 for preventing removal is formed on the outer periphery of the main body, and a split groove 44 is formed on the main body 4. After this anchor bolt is inserted into the stop hole 51 of the concrete foundation 5 from the uneven strip side, it is inserted into the shaft hole. When inserting and driving the bar 6 into the hole 41, the bar 6 pushes open the tapered hole 42, and the uneven strips 43 on the outer periphery bite into the inner surface of the stop hole 51.
Fix it.

<Problems to be Solved by the Invention> However, in the conventional anchor bolt described above, a pilot hole 41 is drilled in the center of the solid material having a round shaft.
1 is cut with a taper reamer to form a taper hole 42, and an uneven strip 43 and a split groove 44 are cut in the direction of the cylinder axis on the outer circumferential surface, and the reaming and cutting process requires a great deal of effort and production bad sex,
This is one of the reasons for the increase in costs.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a novel method for manufacturing anchor bolts that achieves cost reduction through mass production and improves accuracy.

<Means for Solving the Problems> To explain the means of the present invention for achieving the above object, the present invention is a method for manufacturing an anchor bolt, which includes a cylindrical molded hole, a hole continuously connected to the molded hole, and a method for manufacturing an anchor bolt. A cylindrical material is press-fitted into a forming die that has a tapered hole with an enlarged inner diameter extending toward the opening, and an uneven strip formed on the inner surface of the tapered hole, and a cylindrical part that fits the forming hole is formed at one end of the material, and a tapered part is formed at the other end. A tapered part that fits the inner surface of the hole, and a first part that forms uneven stripes on the outer peripheral surface of the tapered part.
The first step is to insert the material from the cylindrical side into the die, which has a forming hole with the same inner diameter as the cylindrical forming hole, forcefully pass through the tapered part, and return the cylindrical part on which the uneven stripes are formed to its original diameter. The two steps and the third step of forming grooves along the cylinder axis in the uneven stripes of the material are performed consecutively.

<Function> As described above, after press-fitting a cylindrical material into a forming die and forming a cylindrical portion at one end of the material, a tapered portion at the other end of the material, and uneven stripes for preventing slippage on the outer peripheral surface of the tapered portion, This material is forcibly passed through the forming hole of the die again, and after the tapered cylindrical part with the uneven stripes is returned to its original diameter, the split grooves are formed. This invention has the effect of achieving the purpose of the invention, such as labor saving in manufacturing operations, mechanical mass production, and cost reduction of anchor bolts.

<Example> This invention press-fits a cylindrical material into a forging forming die, enlarges the end of the material, forms an uneven strip on the outer peripheral surface, and forces the material to pass through the die hole again to have an uneven strip. This is to return the tapered cylindrical portion to its original outer diameter, and in the first step, the cylindrical forming hole 10, this forming hole 10
A cylindrical material 2 is press-fitted into a forming die 1 having a tapered hole 11 whose inner diameter is enlarged continuously toward the opening side and an uneven strip 12 formed on the inner surface of the tapered hole 11 (Fig. 1), and then forged. Through processing, a cylindrical portion 21 that fits the forming hole 10 is formed at one end of the material 2, a tapered portion 22 that fits the inner surface of the tapered hole 11 at the other end, and an uneven strip 23 is formed on the outer circumferential surface of the tapered portion 22. 2
figure).

Next, for the forming die 3 having a forming hole 31 having the same inner diameter as the cylindrical forming hole 10 (FIG. 3),
The material 2 is inserted from the cylindrical portion 21 side, forced to pass through the tapered portion 22, the cylindrical portion on which the uneven strips 23 are formed is returned to its original outer diameter, and the inner hole is formed into a tapered hole 24 (FIG. 4). .

In the next step, screws are machined at the end of material 2,
Anchor bolt 2a as shown in FIG. 5 is formed by cutting grooves on the other end.

<Effects of the Invention> As described above, this invention press-fits a cylindrical material into a molding die to form a cylindrical portion at one end of the material, a tapered portion at the other end of the material, and uneven stripes on the outer peripheral surface of the tapered portion. After that, this material is forced to pass through the forming hole of the forming die again, the tapered part having the uneven stripes is returned to its original outer diameter, and the split groove is formed in the cylindrical part. According to this method, all of the constituent parts can be processed by forging, which greatly simplifies the work, facilitates mechanical mass production, and reduces the cost of the anchor bolt. In addition, since mechanical mass production is possible, the accuracy of the anchor bolt is improved, and there are no defective bolts, which achieves the objectives of the invention.

[Brief explanation of the drawing]

Figures 1 to 4 are process diagrams showing the manufacturing method of the present invention;
FIG. 5 is a longitudinal sectional view of the anchor bolt, and FIG. 6 is a diagram showing a conventional example. 1... Molding die, 10... Cylindrical forming hole, 1
1... Tapered hole, 12... Uneven strip, 2... Material,
21... Cylindrical part, 22... Tapered part, 23... Concave and convex stripes, 3... Molding die, 31... Molding hole.

Claims (1)

[Scope of Claims] 1. A cylindrical material is press-fitted into a forming die that has a cylindrical forming hole, a tapered hole whose inner diameter is enlarged continuously to the opening side, and an uneven strip formed on the inner surface of the tapered hole. a cylindrical part that fits the forming hole at one end of the material, a tapered part that fits the inner surface of the tapered hole at the other end, and a first step of forming an uneven strip on the outer peripheral surface of the tapered part; and the cylindrical forming hole. A second process involves inserting the material from the cylindrical side into a die that has forming holes with the same inner diameter, forcing it to pass through the tapered part, and returning the cylindrical part with the uneven stripes to its original diameter. A method for manufacturing an anchor bolt, characterized by continuously performing a third step of forming a split groove along the cylinder axis direction in the part.