JP2000317862A - Perforating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly perform stage switching operation by aligning the tip projection of a punch member with a working position marked on a work surface, striking the head of the punch member to carve a center hole in a working position, and performing perforation to the center hole. SOLUTION: On a work surface W where previously right-angled marking-off lines A are drawn, a work abutting surface of a guide main body 2 held by a worker's hands M is allowed to abut on the work surface W, and each vertex 7a formed in the center aligning part 4 is located to position on the marking-off lines A. With the guide main body 2 held, the head 1a of a punch member is struck by a hammer 18, the tip projection 1b is moved vertically to the work surface W, and a center hole is carved in the perforating center position. Further, perforation is performed to the center hole by a twist drill or the like. Thus, the manhour for perforation can be reduced and stage switching can be smoothly done.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling method, and more particularly to a drilling method capable of accurately determining a center position of a drilling process when a workpiece is drilled by using a lathe or a drilling machine.

[0002]

2. Description of the Related Art When drilling a work using a lathe or a drilling machine, it is necessary to accurately determine the center position of the drilling as a pre-process. Conventionally, for example, the following method has been adopted to determine the center position. First, a score line is drawn manually at the center position on the work surface, a center punch (center hole engraving tool) grasped by hand is set at the center position, and the center punch is hit with a hammer from above to perform punching. . Next, a conical center hole is formed in the punched position by a center drill set on a drilling machine. Thereafter, the center hole was finally drilled with a twist drill or the like set on a drilling machine.

[0003]

However, in the above prior art, a step of performing punching with a center punch,
The process of engraving the center hole with a center drill and the process of drilling with a twist drill
It requires a process. For this reason, for example, there is a problem that a large number of man-hours are required when performing a setup change.

[0004] Further, since there is an individual difference in the accuracy of the punching by the center punch, there is also a problem that the positions of the drilled holes tend to vary.

[0005] Therefore, an object of the present invention is to reduce the number of steps for drilling, so that, for example, a setup change can be performed smoothly. Another object of the present invention is to improve the accuracy of a punching position by improving the accuracy of punching.

[0006]

According to the present invention, there is provided a punching method for forming a center hole in a work surface with a tip projection, and a punch member perpendicular to the work surface. A center position formed in the center hole engraving jig using a center hole engraving jig provided with a guide body formed with a through hole through which the punch member slidably penetrates. The aligning portion aligns the tip projection of the punch member at the processing position marked on the work surface, strikes the head of the punch member, and engraves a center hole at the processing position. It is characterized by performing drilling.

According to the present invention, a hole is formed by a center hole forming jig. In addition, punching is performed and a center hole is formed directly. Therefore, unlike the conventional drilling method, there is no need to perform an independent operation of engraving the center hole.
Drilling can be performed in a form in which steps are omitted. Therefore, drilling can be performed in two steps.

At this time, it is desirable that the center hole be cut by using a punch having a tip angle of 60 ° or more and 90 ° or less.

A more desirable angle is 80 ° or less, and more preferably 70 ° or less.

[0010]

Embodiments of the present invention will be specifically described below with reference to the drawings. Before describing the drilling method according to the present invention, first, a center hole engraving jig suitable for the drilling method according to the present invention will be described. FIG. 1 is an exploded perspective view of a center hole engraving jig used in the center hole engraving method according to the present invention, and FIG. 2 is a side sectional view thereof. As shown in FIGS. 1 and 2, a center hole engraving jig J includes a punch member 1 for engraving a center hole on a work surface with a tip protrusion 1 b, and the punch member 1 is vertically attached to the work surface. Guide body 2 having a through hole 12 through which punch member 1 slidably penetrates for guiding
And a punch member 1 provided at the base end 5 of the guide body 2.
When the abutting portion 3 of the guide main body 2 is brought into contact with the elastic support portion 6 for urging and supporting the punch member 1 at a position spaced from the work surface by a predetermined distance, the punch member 1 is moved to the processing position marked on the work surface. Center positioning section 4 for positioning tip projection 1b
It is composed of

The punch member 1 is a columnar member having a large diameter so that the head 1a can be easily hit with a hammer, and a sharp tip projection 1b formed at a lower tip portion along the axis. A punch hole is engraved on the work surface. The angle of the tip protrusion 1b affects punching accuracy, which will be described later.

The guide body 2 has a cylindrical shape in which a cylindrical hole through which the cylindrical punch member 1 slides is formed, and this cylindrical hole forms a through hole 12. Further, a center alignment portion 4 for determining a center position is provided at the distal end contact portion 3 of the guide body 2, and an elastic support portion 6 such as a coil spring is connected to the base end portion 5 of the guide body 2. ing.

A cover 11 is provided on the upper end 17 of the elastic support 6.
To cover the upper end 5 of the guide body 2.
1 is slidably fitted. Between the lower end portion 15 of the elastic support portion 6 and the base end portion 5 of the guide body 2, a cushion member 16 for reducing the impact when hitting with a hammer or the like is interposed. In the cover 11, an insertion hole 11a for the punch member 1 is formed in the center of the upper surface of the guide body 2.

The punch member 1 is provided with an insertion hole 11 of the cover 11.
a and inserted into the center of the elastic support portion 6 and slidably inserted into the through hole 12 of the guide body 2. The elastic support portion 6 urges the punch member 1 upward and urges the punch member 1 so that the punch member 1 does not fall off the guide body 2.

Further, the intermediate portion 14 of the guide body 2 is formed to have a diameter such that it can be easily held by the hand, and is knurled to prevent slippage.

The through hole 12 formed in the guide body 2 is
It is composed of an upper hole 12a, an intermediate hole 12c, and a lower hole 12b. Of these, upper hole 12a and lower hole 12b
Is formed so as to have substantially the same diameter as the diameter of the punch member 1, and the intermediate portion 12c has a diameter slightly larger than the upper hole 12a and the lower hole 12b in order to reduce the frictional resistance of the punch member 1 in the vertical movement. Is formed. Also, the through holes 12
Are formed such that the center line thereof is perpendicular to the workpiece contact surface 9. Furthermore, the through hole 12 is
A tapered hole portion 13 is formed at the end of the hole in contact with (see FIG. 4) so that the punch member 1 can easily come and go.

Further, as shown in FIG. 3, the center alignment portion 4 has a pointed apex at an angular position where the periphery of the distal end of the guide body 2 is divided into four equal parts. The pointed apex can be used as the projection 7 so that the apex 7a is formed. Although not shown, it may be formed in a V-shaped concave portion so as to have a cut end.

In the present embodiment, the friction member 10 is formed on the front end contact portion 3 of the guide main body 2. However, a hard rubber or the like may be adhered, and a knurl is formed on the work contact surface 9. You may.

Next, a drilling method according to the present invention will be described with reference to FIGS. Here, a method for drilling using the center hole engraving member J described so far will be described. First, the work contact surface 9 of the guide body 2 gripped by the worker's hand M on the work surface W on which the right-angled score lines A, A are drawn in advance.
Is brought into contact with the work surface W. At the same time, the vertices 7a, 7a,.
Position it so that it is on top. After the positioning, the operator holds the guide body 2 while holding the hammer 18.
When the head 1a of the punch member 1 is hit, the tip protrusion 1b of the punch member 1 moves perpendicular to the work surface W.

In this manner, the center hole is formed at the center position of the work for boring. Drilling is performed on the center hole with a twist drill or the like attached to a drilling machine (not shown).

By the way, the accuracy at the time of making this hole is as follows.
It is affected by the tip angle θ of the tip projection 1b of the punch member 1 shown in FIG. Specifically, the smaller the tip angle θ, the higher the accuracy. The reason that the smaller the tip angle θ is, the higher the accuracy is. The smaller the tip angle θ is, the smaller the opening area of the center hole to be formed is.

On the other hand, if the tip angle θ is too small, the accuracy is improved, but the tip projection 1
b is likely to be destroyed, resulting in disadvantages such as necessity of replacement after several uses.
Therefore, an experiment described later was performed. As a result, the tip angle θ
Has been found to be between 60 ° and 90 °. That is, when the tip angle is less than 60 °, the tip projection 1b is easily damaged. Conversely, if the angle exceeds 90 °, the accuracy is reduced.

[0023]

Embodiments of the present invention will be described below. The inventor conducted the following experiment in order to confirm the accuracy of the drilling method according to the present invention. That is, in the center hole engraving jig J shown in FIG.
, The tip angle θ of the tip projection 1b at
An experiment was performed in which the center was drilled 0 times. The angles set at this time are 50 °, 60 °, 70 °, 80 °, 9
There are six types, 0 ° and 120 °. An experiment was also conducted on the conventional drilling method shown in the above-mentioned conventional technique. The results are shown in FIGS.

Considering the results shown in FIGS. 6 to 8, when the accuracy is judged based on the results of the conventional drilling method shown in FIG. 8B, the tip angle θ shown in FIG. Was 60 °, very good accuracy was shown. Hereinafter, the accuracy decreases as the tip angle θ increases, when the tip angle θ is 70 ° shown in FIG. 6B, 80 ° shown in FIG. 7A, and 90 ° shown in FIG. 7B. The result was In the case of 120 ° shown in FIG. 8A, the result was inferior in accuracy to the conventional processing method. When the experiment was performed with the tip angle θ set to 50 °, the tip projection 1b of the punch member 1 was broken in the middle, and it was impossible to continue the experiment thereafter. Is not listed.

From the above experimental results, the tip angle is 6
It has been found that it is preferable to set the angle in the range of 0 ° to 90 °.

[0026]

As described above, according to the present invention, the number of steps required for drilling is reduced, so that, for example, a change in setup can be smoothly performed. Moreover, since the accuracy of punching can be improved, the accuracy of the drilling position can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a center hole engraving jig used in a drilling method according to the present invention.

FIG. 2 is a side sectional view of a center hole engraving jig.

FIG. 3 is a bottom view of the center hole engraving jig.

FIG. 4 is an explanatory diagram of a drilling method according to the present invention.

FIG. 5 is an enlarged view of a tip protrusion of a punch member in a center hole engraving jig.

FIG. 6 is a diagram showing the results of an example of the drilling method according to the present invention.

FIG. 7 is a view showing the results of another embodiment of the drilling method according to the present invention.

FIG. 8 is a diagram showing the results of another embodiment of the drilling method according to the present invention and the results of a conventional drilling method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Punch member 1a Head 1b Tip projection 2 Guide body 3 Tip contact part 4 Center alignment part 12 Through hole J Center hole engraving jig W Work surface θ Tip angle (of tip projection)

Claims (2)

[Claims] 1. A punch member for engraving a center hole in a work surface with a tip projection, and a through hole through which the punch member slidably passes in order to guide the punch member in a direction perpendicular to the work surface. Using a center hole engraving jig provided with a guide body formed with a guide body, a center alignment portion formed on the center hole engraving jig is used to move the tip of the punch member to a processing position marked on a work surface. A boring method, comprising: aligning a projection; hitting a head of the punch member; and engraving a center hole at the processing position; and boring the center hole. 2. The drilling method according to claim 1, wherein a center hole is formed by using a tip end of the punch member having a tip angle of 60 ° or more and 90 ° or less.