JPS5856497B2 - perforation cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a perforation cutter for making holes in concrete walls, etc. for piping and wiring work for water, gas, electricity, etc.

[Prior art]

Conventionally, as a general method for drilling holes for piping and wiring in a concrete wall, etc., an electric or pneumatic core bit or the like is used to drill only from one side of the wall surface to penetrate the hole.

In this case, a large amount of retraction often occurs at the periphery on the other side of the hole, which poses a problem in construction.

In addition, as a method to prevent the above-mentioned intrusion, a hole is drilled halfway from one side of the wall surface, and then a plurality of small holes indicating the hole position are drilled from that hole to the other side, and these small holes are used as indicators to drill from the other side. Some drill holes are drilled through the hole, but in this case, the holes may be misaligned, and it takes a long time to drill the holes.

[Purpose of the invention]

The purpose of the present invention is to prevent the occurrence of retraction of the large hole edge to be opened, and to enable efficient drilling work without eccentricity of the opening shaft.

[Structure of the invention]

The structure of the present invention is such that a shank is connected to the rotating shaft of the drill body, and a cylindrical first cutter and a removable center drill protruding from the tip of the first cutter are attached to the shank. After partial drilling from one side, an auxiliary shank replaces the center drill and is detachably connected to the shank, and a first blade is attached to the auxiliary shank.
It has a second cutter facing the cutter.

With the above configuration, drilling is started from one side of the wall using the center drill for centering, and the S first cutter is used to drill halfway through the wall.After that, the center drill is replaced with the auxiliary shank, and the center drill is attached to the auxiliary shank. A small-diameter guide hole was drilled from the other side wall using the second cutter (while guiding the auxiliary shank).
The hole can be made with a cutter, and since the cutter blade starts drilling from the outside on both sides of the wall surface, it is possible to prevent the hole from being pulled in, and the hole to be drilled can be formed coaxially.

〔Example〕

Hereinafter, the present invention will be explained based on the embodiments shown in the drawings.

Figure 1 is a cross-sectional view showing the start of drilling 54 holes in a concrete wall. In the figure, 1 is the drill body, and 2 is the drill body 1.
(This yank is installed on the same axis, 3 is the same yank 2.
A cylindrical first cutter with an open end, which has a blade 3a at its tip and a chip groove 3b on its outer periphery, is fixed concentrically to the shank 2; This is a center drill for installation.

The center drill 4 is attached to the first cutter 3 when installed on the shank 2.
The size and shape should be such that it protrudes the required length from the tip.

With this first cutter 3 and center drill 4 attached,
The procedure for performing drilling work on the concrete wall 5 will be described below.

First, a center hole C is drilled into the concrete wall 5 by passing the tip of the center drill 4 through the other wall surface B at the center of the desired drilling position in the concrete wall 5 (see FIG. 1).

Further, by moving the center drill 4 forward along the center hole C, the blade 3a of the cutter 3 comes into contact with the wall surface Al, and then the cutter 3 starts drilling the target hole.

In this state, the cutter 3 moves forward with the center drill 4 guided by the center hole C, so that the cutter 3 can drill a hole centered on the center hole C without the drill body 1 wobbling.

At a desired position during the drilling, the drilling is temporarily interrupted, the drill body 1 is moved back, and the tip of the center drill 4 is separated from the concrete wall 5 (see FIG. 2).

Next, as shown in FIG. 3, remove only the center drill 4 from the shank 2, and attach the auxiliary shank 6 to the center drill
Install it instead.

The auxiliary shank 6 has an elongated outer diameter smaller than the diameter of the center hole drilled by the center drill 4, and has a G-thread screw 10 at its tip so that a presser nut 9 can be screwed onto it. be.

With the auxiliary shank 6 attached, the auxiliary shank 6 is inserted into the center hole from the wall A side and projected toward the wall B side.

Next, a second cutter 7 having substantially the same shape as the first cutter 3 is formed so that only the cutting edge direction of the blade 3a and the threading direction of the chip groove 3b on the outer periphery are opposite to the first cutter 3. 1 katsuta 3
It is slidably attached to the auxiliary shank 6 within a certain range so as to face the shank.

After installing the second cutter 7, the amount of movement of the auxiliary shank 6 to the left in FIG.
It is preferable to configure the blades of the second cutters 3 and 7 so that they do not come into contact with each other.

Note that 8 is extrapolated to the auxiliary yank 6 and the second cut 7 is
A spring 9 biases the second cutter 7 in the direction of the first cutter 3 via the same spring 8.

This spring 8 is connected to the second spring on the side remote from the drill body 1.
This is to absorb the vibration caused by drilling by the cutter 7 and to prevent the auxiliary yank 6 from shaking to improve drilling accuracy.

With the second hook 7 attached via the G auxiliary shank 6 as described above, when the drill body 1 is driven and pulled in the direction of the arrow in the figure as shown in FIG. 3, the auxiliary shank 6 is guided to the center hole C. While moving, remove the second cutter 7 from the wall B side.
starts drilling.

In this drilling by the second cutter 7, the auxiliary shank 6
is guided to the center hole C drilled during the drilling process by the first cutter 3, so the auxiliary shank 6 moves in the axial direction without being displaced.

Therefore, the second cutter 7 attached to the auxiliary shank 6
It is possible to open four holes so as to match the holes drilled by the first cutter 3.

By the above-mentioned drilling by the second cutter 7, the first cutter 3
By communicating with the hole opened in , it is possible to drill a hole in the concrete wall 5, and after the work is completed, the second cutter 7 can be pulled out by moving the drill body 1 further to the left in Fig. 3. .

〔effect〕

As described above, according to the present invention, since the cutter blade abuts both side wall surfaces from the outside, edge chipping does not occur.
By using the center hole, it is possible to provide coaxially aligned holes through the hole.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a state in which a center hole is opened by a drilling cutter according to the present invention, Fig. 2 is a cross-sectional view showing a state in which a hole is drilled by a first cutter, and Fig. 3 is a state in which drilling is started by a second cutter. FIG. 1 Nitrile body, 2: Shank, 3: No. 1 cutter, 3a
: blade, 3b: chip groove, 4: center drill, 5: concrete wall, 6: auxiliary shank, 7: second cutter, 7a: blade.

Claims (1)

[Claims] 1. A shank coaxially connected to the rotating shaft of the drill body, a cylindrical first cutter concentrically connected to the shank and having an open tip and a blade at the tip, and the above-mentioned cutter inside the first cutter. a center drill coaxially and removably connected to the shank and projecting and extending from the tip of the first cutter; a long auxiliary shank that replaces the center drill and is removably attached concentrically to the shank; and the auxiliary shank. and a cylindrical second cutter whose blade is attached to face the first cutter.