JPH0647459A - Punch for perforating hollow square tube and perforating method - Google Patents

Abstract

PURPOSE:To easily perforate a circular or square hole in a hollow square tube by making a cross sectional outer circumference of a taper like U shaped point part whose width is reduced as near the top the same outer diameter with a circular column part continued thereto. CONSTITUTION:In a process A, the tip of a punch 10 begins to penetrate in a hollow square tube 20. When the punch 10 is lowered until a position B, a V-shaped taper tip part 13 penetrates while forming a refracting part 21 as if a wall surface of the tube 20 is enlarged in left and right directions. In the state of the process B, an almost square-shaped hole is perforated on the tube 20. Further, when the punch 10 is lowered to the position C, the circular column part 14 of an edge is penetrated in the hollow square tube 20, the circular hole is formed, and at the same time the bending part 21 remaining around the hole is dropped as a separated piece 22. If the lowering of the punch 10 is stopped at the state B, the almost square shape can be freely formed from a small width to a large width without using a core metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal working punch for punching a circular or square hole in a side surface of a hollow square pipe and a method for punching the punch, and particularly to a circular or square side surface of the hollow square pipe without using a cored bar. The present invention relates to a punch for making a hole and a processing method.

[0002]

2. Description of the Related Art It is frequently practiced to make a hole in the side surface of a hollow square pipe to connect the pipes or to insert other parts. For example, machining as shown in FIGS. The method is common. In FIG. 4, the hollow square pipe 6
To make a circular hole in 5 using a punch 64, upper and lower molds 61 and 62 are prepared, and a series of punches 6 are formed in the upper mold 61.
4 must be set, and the core metal 63 inserted in the hollow square pipe 65 and receiving the punch 64 must be set in the lower mold 62.

As shown in FIG. 5, in the state (A) before punching, the core metal 63 is provided with a hole 68 slightly larger than the outer diameter of the edge 66 at the lower end of the punch 64. When the punch 64 is lowered to the state of (B), the edge 66 penetrates the wall surface of the hollow pipe 65 to form the hole 70, and the punched metal piece 72 falls.

FIG. 6 shows a conventional method in which a square hole is formed in a hollow square pipe 85 by using a punch 84. Upper and lower molds are prepared and the lower mold is inserted into the hollow square pipe 85. The core metal 83 for receiving the punch 84 must be set. In the state (A) before punching in FIG. 6, the core metal 83 is provided with a concave groove 88 slightly larger than the outer shape of the edge 86 at the lower end of the punch 84. When the punch 84 is lowered to the state (B), the edge 86
Form a hole 90 through the wall surface of the hollow pipe 85, and the punched metal piece 92 falls.

In the conventional die structure, particularly when the square pipe is long and a plurality of holes are machined at the same time, extra man-hours are required for attaching and detaching the square pipe to the core metal of the die. Since this requires precision and man-hours for manufacturing the core metal,
There are drawbacks such as high cost. Furthermore, as shown in FIG.
When the outer diameter of the hole 70 to be drilled (the outer diameter of the edge 66) is close to the inner width of the hollow square pipe 65, it becomes impossible to make the hole 68 in the core metal 63,
The core will be damaged during processing. Furthermore, since the periphery of the holes 70, 90 is deformed and burrs are generated on the inner surface after processing, the work of pulling out the hollow square pipes 65, 85 from the cored bar is not easy due to catching in Paris, etc. However, there is a drawback in that a separate process is required.

[0006]

SUMMARY OF THE INVENTION A main object of the present invention is to process a circular or square hole in a hollow square pipe.
It is to simplify the processing process and speed up the work. Another object of the present invention is to eliminate the need for a cored bar when processing a circular or quadrangular hole in a hollow square pipe, thereby reducing the manufacturing cost and the number of processing steps.

[0007]

The above-mentioned object of the present invention is a punch for making a hole in the side surface of a hollow square pipe, and the width of the edge of the punch tip decreases as it goes forward. This is achieved by a hollow square pipe punch for punching, which is composed of a tapered V-shaped tip portion and a cylindrical portion which is continuous with the tapered V-shaped tip portion, and the cross-section outer circumference of the V-shaped tip portion has the same outer diameter as the cylindrical portion.

When the punch having the above structure is used,
When the punch penetrates the square pipe, the tapered V-shaped tip first penetrates, and the tapered edge part pushes the wall to the left and right, and the partial arcuate cutting surface and linear pushing A substantially rectangular hole consisting of a part and a part is formed.
Then, as the punch penetrates, the width of the partial arcuate cut surface increases, and when the cylindrical portion of the punch begins to penetrate the wall surface, a circular hole is formed next time. Since a series of these drilling operations are executed in an instant, if the distance for lowering the punch is reduced, the drilling operation will end with a substantially square hole, and if the distance for lowering the punch is increased, a circular hole will be created. The drilling work is completed in the formed state.

In these series of operations, it is not necessary to use a core bar having high precision and high rigidity as in the conventional case, and the mold can be a mold having a simple shape on the lower side. Thus, the cost of manufacturing the cored bar is reduced, the die is simplified, and the cost is reduced. The time required for inserting and removing the core bar is not required, and the work time is shortened and the efficiency is improved. Since the shearing press force required for making a hole can be made smaller than before by gradually shearing, the press to be used can have a small pressing force, and the cost can be further reduced.

The present invention, as another embodiment of the punch,
The edge of the punch tip is composed of a tapered V-shaped tip portion whose width decreases as it goes forward and a prismatic portion that is continuous with it. The depth dimension of the V-shaped tip portion is the same as the prismatic portion. We provide punches for drilling hollow square pipes.

When the punch for punching with such a structure is used,
When the punch penetrates into the square pipe, the tapered V-shaped tip portion penetrates first, and the tapered edge portion pushes the wall surface to the left and right, so that the parallel linear cutting surface and the linear pressing are performed. A square hole consisting of a part and a part is formed. Then, as the punch penetrates, the width of the parallel straight cut surface increases, and when the prismatic portion of the punch begins to penetrate the wall surface, a square hole is formed next time. Since a series of these drilling operations are executed in an instant, if the distance for lowering the punch is small, the drilling work will end with a small square hole, and if the distance for lowering the punch is large, a large square hole will be created. The drilling work is completed with the formation of the holes.

The present invention further provides a method of punching the side surface of the hollow square pipe by using the above-mentioned punch without inserting a core metal into the hollow square pipe.
By using this method, speeding up of the drilling process and reduction of working cost can be achieved. Other features and advantages of the present invention will be apparent from the following description with reference to the embodiments of the accompanying drawings.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a punch 10 for punching according to the present invention.
And a hollow square pipe 20 such as a steel pipe. The punch 10 is a shank 11 for holding with a chuck.
And the edge 12 at the tip. The edge 12 at the tip of the punch has a tapered V shape whose width decreases as it goes forward.
It is composed of a character-shaped tip portion 13 and a cylindrical portion 14 continuous with the tip portion 13. Square pipe 20 is a simple mold 25
Is set to.

FIG. 1A shows a punch 10 and a hollow square pipe 2.
0 shows the whole, and FIG. 1 (B) shows a bottom view of the punch 10 as seen from the lower side (W direction). 1 (C), (D) and (E) respectively show the cross-sectional shape of the punch, and the shank 11 has a circular cross section with a large outer diameter.
The cross section of the cylindrical portion 14 is a circle having a smaller outer diameter than that, and the cross section of the tip portion 13 is formed by parallel linear side surface portions 13A and 13B and partial arcuate cutting surfaces 13C and 13D.
The outer diameters of the arcuate cut surfaces 13C and 13D are continuously formed so as to be the same as the outer diameter of the cylindrical portion 14.

FIG. 2 shows a step of processing a hole using the punch 10 shown in FIG. In step A, punch 1
The 0 tip begins to penetrate the hollow square pipe 20. When the punch 10 is lowered to the position B, the tapered V-shaped tip portion 13 pushes the wall surface of the pipe 20 to the left and right, and the bent portion 21 is formed while penetrating. In the state of step B, the pipe 20 is provided with a substantially rectangular hole as shown in FIG.

When the punch 10 is further lowered to the position C, the cylindrical portion 14 of the edge penetrates the hollow square pipe 20 to form a circular hole as shown in FIG. The bent portion 21 remaining in the
And drop it. If the lowering of the punch 10 is stopped in the state shown in FIG. 2 (B), a substantially square hole can be freely formed from a small width to a large width, which has the advantage of widening the punch application range. To be

FIG. 3 shows another embodiment of the present invention, in which a punch can be used to make a square hole on the side surface of the hollow square pipe. The punch 30 is composed of a shank 31 for chucking and a tip edge 32, and the punch tip edge 32 is continuous with a tapered V-shaped tip portion 33 whose width is gradually reduced. And a prism portion 34. The square pipe 40 is set in a mold having a simple shape.

FIG. 3A shows a punch 30 and a hollow square pipe 4.
0 represents the whole, and FIG. 3B shows a bottom view of the punch 30 as viewed from the lower side (P direction). 3C, 3D and 3E respectively show the cross-sectional shape of the punch, and the shank 31 has a cross-section of a circle with a large outer diameter.
The prismatic portion 34 has a quadrangular cross section, and the pointed portion 33 has a cross section formed with parallel linear side surface portions 33A and 33B and parallel linear cutting surfaces 33C and 33D. V-shaped tip 3
The depth dimension of 3 is continuously formed so as to be the same as the depth dimension of the prismatic portion 34.

The step of forming a hole using the punch 30 of FIG. 3 is similar to the step shown in FIG. 2, and in the first step, the tip of the punch 30 begins to penetrate the hollow square pipe 40. When the punch 30 is lowered to the next position, the tapered V-shaped pointed portion 33 pushes the wall surface of the pipe 40 to the left and right, and penetrates while forming a bent portion. In this state, the pipe 40 is shown in FIG.
A square hole as shown by will be drilled.

When the punch 30 is further lowered to the next position, the prism portion 34 of the edge penetrates the hollow square pipe 40 to form a square hole as shown in FIG. The bent part that remained in step 1 is separated and dropped. If the lowering of the punch 40 is stopped in the same state as shown in FIG. 2 (B), a square hole can be freely formed from a small width to a large width.
The advantage is that the punch application range is expanded.

[0021]

As described in detail above, according to the present invention, it is possible to use a metal mold having a simple shape on the lower side without the need for a highly accurate and highly rigid cored bar. become.
Thus, the cost of manufacturing the cored bar is reduced, the die is simplified, and the cost is reduced. The time required for inserting and removing the core bar is not required, and the work time is shortened and the efficiency is improved. Since the shear press force required to make a hole is smaller than before, the press used can have a small pressing force, and the advantages such as cost reduction can be obtained. There are some remarkable effects.

[Brief description of drawings]

FIG. 1 is a perspective view showing a punching method using a punch according to the present invention and a sectional view of the punch. 1A is a perspective view, FIG. 1B is a bottom view seen from W, FIG. 1C is a horizontal sectional view taken along line X, FIG. 1D is a horizontal sectional view taken along line Y, and FIG. 1E is a horizontal sectional view taken along line Z. .

FIG. 2 is a schematic sectional view showing a drilling process according to the present invention. 2A, 2B, and 2C show each process.

FIG. 3 is a perspective view showing a punching method using a punch and a sectional view of the punch according to another embodiment of the present invention. Figure 3A
Is a perspective view, FIG. 3B is a bottom view seen from P, FIG. 3C is a horizontal sectional view taken along line Q, and FIG. 3D is a horizontal sectional view taken along line R.
E is a horizontal sectional view taken along the line S.

FIG. 4 is a perspective view showing a hole drilling method according to a conventional example.

FIG. 5 is a schematic vertical cross-sectional view showing a drilling method according to a conventional example. 5A shows a state before drilling, and FIG. 5B shows a state after drilling.

FIG. 6 is a schematic vertical cross-sectional view showing another conventional drilling method. FIG. 6A shows a state before drilling, and FIG. 6B shows a state after drilling.

[Explanation of symbols]

 10,30 Punch 11,31 Shank 12,32 Edge 13,33 V-shaped tip 14,34 Cylinder 20,40 Hollow square pipe

Claims (4)

[Claims] 1. A punch for making a hole in a side surface of a hollow square pipe, wherein an edge of the punch tip has a tapered V-shaped tip portion whose width decreases as it goes forward, and a cylindrical portion continuous with the V-shaped tip portion. A hollow square pipe punch for punching, wherein the V-shaped tip portion has a cross-section outer periphery having the same outer diameter as that of the cylindrical portion. 2. A method of punching a hole in a side surface of a hollow square pipe without inserting a core metal into the hollow square pipe, wherein a tip edge has a tapered shape whose width decreases as it goes forward. A punch for punching, which is composed of a V-shaped tip portion and a cylindrical portion which is continuous with the V-shaped tip portion, and whose cross-sectional outer circumference of the V-shaped tip portion has the same outer diameter as the cylindrical portion, is prepared, and the hollow square pipe is provided with a predetermined distance. A method for making a hole in a hollow square pipe, characterized in that a circular or substantially quadrangular hole is formed by penetrating only a punch. 3. A punch for making a hole in a side surface of a hollow square pipe, wherein an edge of the punch tip has a tapered V-shaped tip portion whose width decreases as it goes forward, and a prism portion continuous with the V-shaped tip portion. And a depth dimension of the V-shaped tip portion is the same as that of the prism portion. 4. A method of punching a hole in a side surface of a hollow square pipe without inserting a core metal into the hollow square pipe, wherein a tip edge has a tapered shape whose width decreases as it goes forward. Prepare a punch for punching, which is composed of a V-shaped tip portion and a prismatic portion continuous with the V-shaped tip portion, and the depth dimension of the V-shaped tip portion is the same depth dimension as the prismatic portion. A method for punching a hollow square pipe, characterized in that a square hole is bored by penetrating a punch.