JP2001030230A - Drill for concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the clogging of an ejection hole for a coolant due to cut dust. SOLUTION: A drill 11 for concrete has a coolant supply hole 15 inside and has an almost cylindrical shank having the fore end closed by the fore end wall 19 and an almost columnar cutting member 25 fixed on the fore end wall of the shank. A slit 27 extending in one direction of the diameter is formed in the cutting member. One end 27 of the slit opens in the outer peripheral part on the side of one end of the diameter, while the other end 31 is positioned between the center 33 of the cutting member and the other end of the diameter and closed. The width of the slit increases gradually toward the open end part from the closed end part. A small hole 21 is provided in the fore end wall of the shank and one end thereof communicates with the coolant supply hole, while the other end faces the slit and opens therein in the vicinity of the closed end part of the slit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill for concrete, and more particularly to a drill suitable for drilling small holes in floors, walls, ceilings, etc. of concrete structures.

[0002]

2. Description of the Related Art Small holes may be drilled for various purposes in the walls and walls of concrete structures. In this case, a drill having a cutting member such as a diamond bit fixed to the tip of a shank is used. .

[0003] In such a drill, a coolant is supplied to a cutting member for the purpose of preventing scattering of dust generated at the time of drilling and suppressing a decrease in drilling ability by suppressing a rise in temperature of the drill. There is something.

Japanese Patent Application Laid-Open No. H11-10425 discloses an example of a type of concrete drill capable of supplying such a coolant. That is, FIG. 3 is a plan view seen from the tip side of the drill, and the drill 1 is composed of a substantially cylindrical diamond bit at the tip of a cylindrical shank 3 having a coolant supply hole 3a therein. It is formed by fixing the cutting member 5. The diamond bit 5 has a slit or notch 7 extending from the outer peripheral portion toward the center, one end being open at the outer peripheral portion, and the other end being closed. On the other hand, at the tip of the shank 3, one end communicates with the internal coolant supply hole, and the other end is provided with an ejection hole 9 opened to face the slit 7 near the outer peripheral portion of the diamond bit 5. A coolant is blown out from the holes 9 to cool the diamond bit 5, and the flow of the coolant is used to promote the discharge of the cutting chips of the concrete.

[0005] In the drill 1, since the ejection hole 9 is located near the outer peripheral portion of the diamond bit 5, as the drilling operation is performed, the closed end of the slit 7 indicated by the symbol A in the figure is removed. The chips entering the region between the ejection holes 9 are hard to move in the outer circumferential direction of the bit 5 in the slit 7 due to the direction of the flow of the coolant from the ejection holes 9, and the chips are located in this region. May easily accumulate, and eventually the jet holes themselves may be clogged. Such a problem,
This occurs not only in the case of drilling in concrete, but also in the case of drilling a waterproof sheet material constructed for the purpose of waterproofing on the roof.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and the present invention has been made to prevent clogging of a coolant ejection hole, to cool a cutting member, An object of the present invention is to provide a drill for concrete that can easily discharge cutting chips.

[0007]

In order to solve the above-mentioned problems, in a concrete drill according to the present invention, a cutting member extends in one diameter direction, and one end is opened at an outer peripheral portion on one end side of this diameter. The other end forms a closed slit between the center of the cutting member and the other end of the diameter. The width of the slit gradually increases from the other end toward the one end. A small hole is provided in the tip wall of the shank, one end of which communicates with the internal coolant supply hole, and the other end of which is open to the slit of the cutting member in the vicinity of the closed end.

In one embodiment, a bottomed slit is formed on the outer surface of the tip wall of the shank at a position corresponding to the slit of the cutting member and extends from the center toward the outer periphery. The slit deepens toward the outer periphery.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the scope of the present invention is not limited to the embodiments described below.

FIG. 1 is a view showing a concrete drill 11 according to a first embodiment of the present invention. FIG. 1A is a plan view, and FIG. It is.

In FIG. 1, reference numeral 13 denotes a substantially cylindrical shank. Inside the shank 13, there is formed a hole 15 extending in the axial direction with its base, that is, the lower end as viewed in FIG.
The hole 15 is formed in multiple stages so that the diameter is gradually reduced from the lower end side, and a female screw 17 is cut in the middle thereof. The drill 11 is attached to a rotating shaft of a drilling machine (not shown) via the female screw 17. Further, a coolant such as water is supplied from the drilling machine into the holes 15.

A cutting member 25, which is a diamond bit in the present embodiment, is fixed to the tip end surface of the shank 13, ie, the outer side surface of the tip end wall 19 closing the tip end of the hole 15, by an appropriate means such as adhesion. The diamond bit 25 is formed in a substantially cylindrical shape, and is positioned and attached to the shank 13 so as to be concentric with each other. As can be seen from the figure, the diameter of the diamond bit 25 is larger than the diameter of the shank 13.

The diamond bit 25 has a slit or notch 27 formed over the entire length in the height direction. The slit 27 is formed so as to extend along one diameter of the diamond bit 25, and one end of the slit 27 is an opening 29 opened at an outer peripheral portion on one end side of the diameter of the diamond bit 25. The other end of the slit 27 is a closed end 31 which is located between the center 33 of the diamond bit 25 and the outer periphery of the other end of the diameter. The shape of the slit 27 is symmetrical with respect to the diameter line, and the width in the direction across the diameter gradually increases from the closed end 31 toward the opening 29.

One end of the tip wall 19 of the shank 13 communicates with the hole 15, and the other end has an outer surface 19 a of the tip wall 19.
, A small hole 21 is formed which opens into the slit 27 of the diamond bit 25. Small hole 21
Is located between the center 33 of the diamond bit 25 and the closed end 31 of the slit 27, and in the present embodiment, is located close to the closed end 31. As is clear from the figure, the small holes 21 are located completely off the center 33. The small holes 21 are ejection holes from which the coolant sent into the holes 15 of the shank 13 is ejected when the drilling operation is performed by the drill 11.

When a drilling operation is performed on, for example, a concrete wall using the drill having the above-described configuration, the upper opening 27a of the slit 27 of the diamond bit 25 is closed by the concrete wall. The lower opening 27b of the slit 27 is closed by the tip wall 19a of the shank 13. In the diameter direction, one of the ends is the closed end portion 31, so that the coolant ejected from the small hole 21 has the center 3 as indicated by the symbol W in the figure.
3 and a violent flow toward the opening 29. Therefore, the concrete swarf entering the slit 27 has the slit 27 generated by the rotation of the drill 11.
In addition to the centrifugal force in the direction of the opening 29, the effect of the flow of the coolant toward the opening 29 acts, and the chips are reliably discharged to the outside of the slit 27 through the opening 29. . At this time, since the width of the slit 27 increases toward the opening 29, it is convenient for discharging chips. Of course, this coolant serves to cool the diamond bit and maintain its cutting ability.

FIG. 2 is a view showing a concrete drill 41 according to a second embodiment of the present invention.
(B) is a cross-sectional view taken along the line B in FIG. The difference between the drill 41 in this embodiment and the drill 11 in the first embodiment is that a recess or a slit 45 is provided on the outer side surface of the tip wall of the shank 43, and is common in other configurations. Therefore, the same reference numerals are given to those common members and configurations, and description thereof will be omitted.

In the tip wall 45 of the shank 43, the slit 27 of the diamond bit 25 is formed on the outer side.
The slit 47 is formed so as to be located below the space. That is, as shown in FIG.
The shank 43 is formed so as to be lower rightward from the central portion of the tip wall to the outer peripheral portion on the opening 29 side of the slit 27 of the diamond bit. In the present embodiment, the shape in the width direction conforms to the shape of the slit 27 of the diamond bit 25, and the width gradually increases toward the outer peripheral opening 47b. The inner end 47a of the slit 45 is located at a position slightly shifted from the center 33 toward the small hole 21.

In the above-described embodiment, the slits or dents 47 formed in the shank 43 increase the space through which the chips flow, make the chips easier to flow, and further prevent the chips from clogging. Increase. Further, the bottom surface of the slit 47 is inclined so as to gradually lower toward the outer peripheral side opening 47b, and the inner end 47
Since a is shifted from the center 33 to the small hole side, even if a thin concrete core is formed in the center portion during drilling, the core hits this inclined bottom surface of the slit 47 and easily breaks, It is easily discharged together with the swarf.

The shape of the slit or depression 47 is not limited to the one described above, but can be changed as needed. For example, the inner end 47a may have a certain depth. The bottom surface may be flat, but in consideration of the flow of cuttings, it is desirable to incline so as to descend toward the outer peripheral portion. The shape in the width direction does not necessarily need to match the shape of the slit of the diamond bit. Although the width may be uniform, a shape that gradually increases toward the outer peripheral portion is desirable in consideration of the flow of the cutting powder.

[0020]

As described above in detail, according to the drill for concrete according to the present invention, the chips are reliably discharged from the slits of the cutting member under the action of the flow of the coolant, and the coolant is ejected by the chips. Hole clogging can be prevented.

When a recess or a slit is provided on the outer surface of the tip wall of the shank corresponding to the slit of the cutting member, the space through which the chips flow is enlarged, and the effect of preventing the chips from being clogged is increased. You.

[Brief description of the drawings]

FIG. 1 is a view showing a concrete drill according to a first embodiment of the present invention.
It is sectional drawing by a B line.

FIG. 2 is a view showing a concrete drill according to a second embodiment.

FIG. 3 is a plan view showing a conventional example.

[Description of Signs] 11 Drill for concrete 13 Shank 15 Coolant supply hole 19 Tip wall 21 Small hole (ejection hole) 25 Cutting member (diamond bit) 27 Slit 29 Opening 31 Closed end

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mikio Sugai 4-1 Kioicho, Chiyoda-ku, Tokyo Asahi Dai-Yammond Industries Co., Ltd. F-term (reference) 3C069 AA04 BA09 BB01 BB02 CA10 DA06 DA07

Claims (3)

[Claims] 1. A substantially cylindrical shank having a coolant supply hole therein, the tip of which is closed by a tip wall, and a substantially columnar cutting member fixed on the tip wall of the shank. In the drill for concrete, the cutting member extends in one diameter direction, one end is opened at an outer peripheral portion on one end side of the diameter, and the other end is between the center of the cutting member and the other end of the diameter. A closed slit is formed, and the width of the slit gradually increases from the other end side toward the one end side, and one end communicates with the coolant supply hole on the tip end wall of the shank, and the other end has A drill for concrete, characterized in that a small hole is provided in the vicinity of the other end of the slit so as to face the slit. 2. The concrete drill according to claim 1, wherein the outer surface of the tip wall of the shank extends from a center to an outer periphery at a position corresponding to the slit of the cutting member. A drill for concrete, characterized in that a bottom slit is formed. 3. The concrete drill according to claim 2, wherein the slit of the shank is deeper toward an outer peripheral portion.