JPH0561045B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a drilling drill for drilling small holes in concrete structures such as walls and ceilings of buildings.

<Prior Art> When installing a decorative board or the like on the wall or ceiling of a building, a large number of small holes are bored in the wall or ceiling, and the decorative board or the like is supported by anchors installed in these small holes.

To drill the above-mentioned small holes, a drilling drill is attached to an electric drill machine, axial vibration and rotational motion are applied to the drill, and the holes are drilled by axial impact breaking and rotary cutting.

A conventional drilling drill is generally a twist drill, which has a shaft with two spiral grooves formed on its outer circumferential surface, a sharpened tip, and a cutting edge formed at the tip.

<Problems to be Solved by the Invention> When a small hole is drilled in a concrete wall, etc. using the above-mentioned twist drill, vibration and loud noise are generated, especially vibration and noise caused by impact fracture, and the cut concrete powder is thrown into the air. scatter. For this reason,
During renovation work for offices, stores, hotels, etc., intense noise and vibrations are transmitted to adjacent rooms near the construction site and rooms on the upper and lower floors, making it impossible to work in these rooms, and causing concrete powder to spread to workers, etc. harm the health of people.

In addition, with conventional drilling drills, it is difficult for the cutting blade to dig into the surface of a concrete wall, etc. at the start of drilling, and the drilling must be performed while applying vibration in the axial direction, so the tip of the drill easily swings, making it difficult for the cutting edge to dig into the surface of a concrete wall etc. It is difficult to drill holes, and the inner surface of the hole tends to be irregularly curved, making it impossible to make regular circular holes.

<Means for Solving the Problems> The present invention was proposed in view of the above, and a cylindrical cutting part is provided at the tip of a shank shaft in which an axial flow path is formed. , the tip surface is recessed to form an edge on the periphery, and a slit that opens across the tip surface and side surface is provided, a cutting edge is formed at the intersection of this slit and the tip surface, and the slit is inserted into the shank shaft. It is designed to communicate with the flow path.

<Function> The present invention has the above-described configuration, and by simply applying rotational motion without applying vibration in the axial direction, the edge formed on the periphery of the tip bites into the surface of the concrete wall, thereby reducing the deflection of the tip of the drill during drilling. In addition, the lubricating fluid supplied from the flow path of the shank shaft cools the cutting edge and flushes away cutting powder to enable smooth cutting, significantly reducing the generation of vibration and noise.

<Examples> The present invention will be described below based on examples shown in the drawings.

As shown in FIG. 1, the drilling drill 1 according to the present invention has a shank shaft 2 in the shape of a round metal bar, with a flow passage 3 formed through the center of the shank shaft 2 in the axial direction.
A mounting male screw portion 4 having a larger diameter than the shank shaft 2 is provided at one end, and a cylindrical cutting portion 5 having a larger diameter than the shank shaft 2 is provided at the other end of the shank shaft 2 concentrically with the shank shaft 2. It will be set up.

The cutting part 5 shown in FIGS. 1 to 3 is made of powdered sintered metal containing diamond powder, and has a sharp edge 6 on the periphery of the tip by recessing the tip surface into a curved shape at an angle of about 30 degrees. Form. Further, this cutting part 5 is provided with a slit 7 whose opening on the side surface runs along the length direction of the cutting part 5 and whose opening at the tip face runs along the radial direction of the cutting part 5. An arcuate cutting edge 8 is formed at a corner portion intersecting the tip surface. The radial length of the slit 7 is larger than the radial length of the cutting portion 5, as shown in FIG. Therefore, when the cutting portion 5 is fixed to the lower end of the shank shaft 2 by fixing means such as brazing, the slit 7 communicates with the flow path 3 of the shank shaft 2.

In order to drill a hole in a concrete wall or the like using the above-described drilling drill, the male mounting threaded portion 4 of the shank shaft 2 is screwed into the mounting portion 10 of the electric drill 9, as shown in FIG. The mounting portion 10 of the electric drill machine 9 is configured to allow the drilling drill 1 to rotate while supplying a lubricating liquid such as water to the channel 3 of the shank shaft 2 from a liquid supply pipe 11.

Therefore, when the drilling drill 1 is rotated while the tip of the drilling drill 1 is in contact with the surface of the concrete wall, the edge 6 digs into the surface of the concrete A and prevents the tip of the drilling drill 1 from swinging out.
A rotating cutting blade 8 progressively cuts and perforates the concrete wall. That is, the drilling drill 1 can drill holes only by rotational motion without having to vibrate in the axial direction unlike conventional products. Since a lubricating liquid such as water is supplied to the slit 7 of the cutting portion 5 from the flow path 3 of the shank shaft 2, this lubricating liquid cools the cutting blade 8. Therefore, the cutting blade 8 not only does not get heated, but also becomes less likely to wear out, and smooth cutting can be continued.

The concrete powder cut by the cutting blade 8 is washed away by the lubricating liquid flowing out from the slit 7, and is discharged onto the surface of the concrete A through the gap B between the inner surface of the hole and the shank shaft 2. Therefore, even if a large number of small holes are continuously drilled in a dry concrete wall or the like, concrete powder will not be scattered into the air. Note that the lubricating fluid and cutting powder discharged onto the surface of the concrete A may be sucked up by a vacuum.

In another embodiment of the cutting part 5 shown in FIG. 4, the slit 7' is formed to be inclined with respect to the length direction of the cutting part 5. When the slit 7' is inclined in this way, the cutting edge 8 formed at the intersection of the slit 7' and the tip end cuts into the concrete surface at an acute angle, so that more efficient cutting can be performed.

Note that the cutting portion 5 of the present invention may be made of the same material as the shank shaft 2. For example, in another embodiment shown in FIGS. 5 and 6, the shank shaft 2' and the cutting part 5' are integrally made of cemented carbide,
A spiral groove 12 is formed on the surface of the shank shaft 2' and the cutting part 5'.
12' is formed, and a slit 7' is formed in communication with the spiral groove 12'. If the shank shaft 2' and the cutting part 5' are made integrally in this way, the connecting part between the cutting part 5' and the shank shaft 2' will not be damaged, and if a spiral groove is formed, the slit 7' Since the lubricating liquid flowing out from the grooves is sent by the rotation of the spiral grooves 12 and 12', the lubricating liquid is efficiently discharged to the concrete surface together with the cutting powder.

Incidentally, when comparing the noise, vibration, and durability when a small hole with a diameter of 6 mm is drilled according to the present invention with that when a hole is drilled using a conventional drill, the following experimental results were obtained.

(1) Comparison of sound pressure levels As a result of measurement at a point 2 meters away, the conventional product
The noise level was 96 dB, but in the present invention, it was 83 dB, which was a reduction of about 13 dB in noise level.

(2) Comparison of noise acceleration levels Measured at a horizontal distance of 50 cm, the conventional product had a level of 111 dB, but the present invention had a level of 95 dB, a reduction of approximately 16 dB.

(3) Vibration level As a result of measuring the vibration level at the center of the floor directly above,
The conventional product had 59dB, but the present invention had 49dB.
This resulted in a reduction of approximately 10 dB. Note that, in general, vibration levels of 55 dB or less are not felt by the human body, so according to the present invention, there is almost no perceptible vibration.

(4) Durability The conventional product had a limit of about 120 holes, but with the present invention, about 600 holes could be opened without re-polishing.

<Effects of the Invention> As described above, according to the present invention, the edge formed on the periphery of the tip immediately bites into the surface of the concrete wall, thereby preventing the tip of the drill from swinging out at the start of drilling. Therefore, even if a large number of small holes are drilled, each small hole can be accurately drilled at a predetermined position.

In addition, the lubricant supplied from the flow path of the shank shaft can cool and moisturize the cutting edge, making it highly durable and capable of smooth cutting over a long period of time. does not scatter into the air.

Furthermore, in the present invention, sufficient cutting can be achieved by simply applying rotational motion, and unlike conventional products, there is no need to apply vibration in the axial direction to cause impact damage. Therefore, even if renovation work is carried out in offices, stores, hotels, or other places where quietness and cleanliness are required, noise and vibrations will not be transmitted to neighboring rooms or rooms on the upper or lower floors near the construction site, and tiles that can break easily will not be transmitted. It is also possible to drill holes in the vicinity of the holes.

Further, since it is not necessary to apply axial vibration only by applying rotational motion, the inner surface of the hole becomes a regular curved surface, and it is possible to open a hole that is closer to a perfect circle than in the past.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially cutaway front view, FIG. 2 is a bottom view, and FIG. 3 is a partially cutaway front view.
4 is a front view of another embodiment of the slit, FIG. 5 is a front view of another embodiment, and FIG. 6 is a sectional view of the embodiment shown in FIG. 5. . 1 is a drilling drill, 2 is a shank shaft, 3 is a flow path,
5 is a cutting part, 6 is an edge, 7 is a slit, 8 is a cutting blade, 9 is an electric drill machine, 11 is a liquid supply pipe, 12,
12' is a spiral groove.

Claims (1)

[Claims] 1 A cylindrical cutting part is provided at the tip of the shank shaft with an axial flow path formed inside, and this cutting part has a
The tip surface is recessed to form an edge on the periphery, and a slit that opens across the tip surface and side surface is provided, a cutting edge is formed at the intersection of this slit and the tip surface, and the slit is inserted into the flow of the shank shaft. A drilling drill for concrete structures, which is characterized by being connected to a road.