HK1107305B - Drill, wall protector and drilling method - Google Patents

Description

Drill, wall surface protection member for drilling, and drilling method

Technical Field

The present invention relates to a drill having a high-hardness bit attached to a distal end of a drill main body, a wall surface protection member for protecting a wall surface when drilling with the drill, and a method of drilling a hole in a wall body using the drill.

Background

As shown in fig. 15 and 16, a drill for drilling a hole in a wall other than concrete is configured by attaching a high-hardness bit 2 to the tip of a drill main body (rod) 1 by brazing or the like, and the bit 2 is formed of cemented carbide or the like in a plate shape having a width dimension W larger than a diameter dimension (diameter dimension of a maximum diameter portion) D of the drill main body. Fig. 15 shows 3 a chuck part which is clamped and fixed to the drill drive sleeve.

The cutter head 2 is generally formed by providing a V-shaped cutting edge portion 5 that protrudes from the tip of the drill main body 1 and performs a cutting action at the tip of the base plate portion 4, and is attached to the drill main body 1 in a state where the V-shaped tip (cutting point) 5a of the cutting edge portion 5 is positioned on the axial center X of the drill main body 1.

Side blades 6, 7 are formed on both side edge portions of the blade portion 5, and the side blades 6, 7 uniformly project radially outward from the outer periphery of the body in the bit attached state.

The above-described drill bit structure is described in, for example, japanese patent application laid-open No. 2005-279853.

As shown in fig. 17 to 19, in such a conventional drill, only the straight hole B having the same diameter can be formed in the wall body a over the entire length. Fig. 17 to 19 show the following. To simplify the drawing, the drill body 1 is shown as a simple circular shaft.

Therefore, for example, as shown in fig. 18, when a process of inserting the anchor 7 into the drilled hole B, expanding and fixing the anchor 7, and fixing the fixing bolt 8 to the anchor 7 in the hole B to attach an instrument or a structure is performed, the fixing force of the anchor 7 to the hole B is not necessarily sufficient, and there is a problem that the attachment state of the object to be attached is unstable.

This problem is not limited to the so-called mechanical fixing method shown in the drawings, but may be improved by filling a hole with a synthetic resin-based adhesive to fix the anchor chemically.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a drill, a wall surface protecting member for drilling, and a drilling method, which can drill a hole capable of significantly improving the fixing force of an anchor.

According to one aspect of the present invention, a drill includes a drill body and a high-hardness bit attached to a distal end of the drill body, wherein a width dimension of the bit is larger than a diameter dimension of the drill body, and the bit is attached in an eccentric state in which a center line in a bit width direction is offset to left and right sides with respect to an axial center of the drill body.

Drawings

Fig. 1 is a side view of the tip portion of a drill tip according to embodiment 1 of the present invention.

Fig. 2 is a diagram for explaining the eccentric rotation of the drill.

Fig. 3 is a view showing a drilling process 1 performed by the drill.

Fig. 4 is a view showing the drilling step 2.

Fig. 5 is a diagram showing a drilling step 3.

Fig. 6 is a diagram showing a state in which drilling is completed.

Fig. 7 is a view showing a state where the anchor is fixed to the hole and the fixing bolt is attached.

Fig. 8 is a view showing a drilling step 1 performed by the drilling method according to embodiment 2 of the present invention.

Fig. 9 is a view showing the drilling step 2.

Fig. 10 is a diagram showing a state in which drilling is completed.

Fig. 11 is a side view of the tip of the drill according to embodiment 3 of the present invention.

Fig. 12 is a perspective view of the bit of the drill.

Fig. 13 is a diagram for explaining a drilling state of the drill.

Fig. 14 is a diagram showing the state of completion of drilling.

Fig. 15 is a perspective view of a conventional drill.

Fig. 16 is an enlarged view of the drill tip portion of the conventional drill.

Fig. 17 is a diagram showing a drilling state of a conventional drill.

Fig. 18 is a view showing a state where the anchor is fixed to the hole.

Fig. 19 is a view showing a state where the fixing bolt is attached to the anchor.

Detailed Description

An embodiment of the present invention will be described with reference to fig. 1 to 14.

Embodiment 1 (see FIGS. 1 to 7)

The basic configuration of the drill is the same as that of the conventional drill shown in fig. 15 to 19.

That is, this drill is configured by attaching a high-hardness tip 12 to the tip of a drill body 11 by brazing or the like, and the tip 12 is formed of cemented carbide or the like into a plate shape having a width dimension W larger than a diameter dimension (diameter dimension of the maximum diameter portion) D of the drill body.

The blade 12 is formed by providing a V-shaped cutting edge portion 14 that protrudes from the tip end of the drill main body 1 and performs a cutting action at the tip end of the base plate portion 13, and side edges 15 and 16 are formed at both side edge portions of the cutting edge portion 14.

In this drill, as a separate structure, the cutter head 12 is attached to the drill body 1 in an eccentric state in which the center line (a straight line passing through the cutting point 14a, which is the apex of the blade portion 14) Y is offset to the left and right with respect to the axial center X of the drill body 1. In the figure, α represents the eccentricity.

Therefore, in the drill with the tip attached, the side blades 15 and 16 are different in size from each other and project radially outward from the outer periphery of the main body.

In addition, it has been confirmed by the inventors that: for example, when drilling a hole for fixing a machine, if the eccentric amount α is set to about 1.0mm to 3.0mm by using a drill having a body diameter D of 16mm and a tip width W of 20mm, the anchor fixing force is sufficiently effective.

In the case of such a drill structure, as shown in fig. 2, the bit 12 rotates eccentrically during drilling and rotates while vibrating the eccentric amount α radially outward with respect to the body 11, so that a hole having a diameter equal to or larger than the bit width W can be drilled by the eccentric rotation.

The specific actions and effects of this point will be described below by taking as an example the working scheme implemented in the mechanical anchor. In fig. 2, 4, and 5, the drill body 11 is simplified to be shown in a simple circular shaft shape.

First, as shown in fig. 3, a straight predrilled hole C1 is cut into a wall body a by a conventional straight drill bit in a length slightly shorter than the depth of insertion of the anchor.

Next, as shown in fig. 4, the drill is inserted into the pre-drilled hole C1, and the cutter head 12 is rotated while being pressed against the bottom surface of the pre-drilled hole, thereby performing secondary cutting.

In the secondary cutting, due to the eccentric rotation of the cutter head 12 shown in fig. 2, a pilot hole C2 having a larger diameter than the pilot hole is continuously drilled in the bottom surface of the pilot hole C1 as shown in fig. 5, and a large pilot hole C having a larger bottom is drilled as a whole as shown in fig. 6.

In this case, if the cutter head 12 having the V-shaped blade portion 14 shown in this embodiment is used, the V-shaped apex (cutting point) 14a of the blade portion 14 comes into point contact with the hole bottom surface, so that the resistance to eccentric rotation is small, and therefore the cutter head is likely to eccentrically rotate. For this reason, the large bottomed hole C, E can be cut naturally and smoothly.

As shown in fig. 7, when the anchor 7 is inserted into the large bottom hole C and expanded, the anchor 7 is expanded to a diameter larger than the diameter of the predrilled hole C1, and is fixed by being pressed against the circumferential surface of the bottom hole.

Therefore, the anchor 7 can be fixed more firmly than when the anchor 7 is tightened only by the pressure of the anchor 7 against the circumferential surface in the straight hole B as shown in fig. 18.

As a result, as shown in fig. 7, when the fixing bolt 8 is screwed into the anchor 7 to attach the tool or the structural member, the stability of the attachment state can be significantly improved.

The effect of this is not limited to the above-described mechanical fixing, but the same effect can be obtained in the case of the chemical fixing in which the hole is filled with a synthetic resin-based adhesive material to fasten the anchor.

Embodiment 2 (see fig. 8 to 10)

Example 2 shows another method of drilling a large bottom hole. The structure of the drill itself is the same as that of embodiment 1.

In embodiment 1, a step of forming a pilot hole C2 by rotating a drill in a pre-cut pilot hole C1 is employed, whereas in embodiment 2, as shown in fig. 8, a straight hole E1 is directly cut by the drill, and then as shown in fig. 9, the entire drill is rotated while being vibrated radially outward (rotated so as to be inclined upward or downward or rightward or to be curved), and as shown in fig. 10, a method of continuously forming a pilot hole E2 is employed.

According to this method, since the bottomed hole E2 is drilled with a larger diameter than the straight hole E1, a large bottomed hole E substantially the same as that of embodiment 1 can be formed.

In this case, compared to embodiment 1, since the irregularities (not shown) caused by the eccentric rotation of the bit 12 are formed on the entire circumferential surface of the hole, it is advantageous to improve the anchor fixing force.

Embodiment 3 (see fig. 11 to 14)

Embodiment 3 shows another structure of the cutter head 12.

(I) The blade 12 is formed by providing a V-shaped blade portion 14 at the tip of the base plate portion 13,

(II) the cutter head 12 is mounted on the bit body 11 in an eccentric state,

(III) side blades 15 and 16 are provided on both side edge portions of the blade portion 14 in a state of protruding radially outward from the drill main body,

(IV) the projecting amounts of the both side blades 15, 16 are different due to the eccentricity of the cutting point 14 a.

The above items (I), (II), (III) and (IV) are the same as those in example 1.

In embodiment 3, the height h2 of the side edge 16 having the larger protrusion amount of the two side edges 15 and 16 is set to be smaller than (e.g., approximately half) the height h1 of the other side edge 15. Hereinafter, depending on the height, the side edge 15 is referred to as a large side edge, and the side edge 16 is referred to as a small side edge.

The inventors have demonstrated that: with this structure, as shown in fig. 13 and 14, the small side cutting edge is deeply cut into the hole peripheral surface, and therefore, a significant unevenness is formed on the hole peripheral surface. Therefore, the fastening force of the anchor can be further improved.

In this case, the inventors also confirmed that: as shown in the drawing, by forming the lower root portion of the small side blade 16, that is, the portion 16a for supporting the load into an arc shape, the load supporting force of the small side blade 16 can be increased, and the breakage thereof can be prevented as much as possible.

In addition, in the present embodiment, a method is adopted in which: a headed cylindrical wall surface protection member 17 is fitted to the drill bit body 11 in advance in a movable fit; at the stage when the hole E has been cut to some extent by the drill, the protective member 17 is inserted into the hole opening portion, and the cutting is continued with the opening edge portion covered with the head portion 17 a.

The protective member 17 is made of metal such as iron or aluminum, or hard plastic, and the outer diameter of the shaft portion is set to be substantially equal to the diameter of the hole E to be cut.

In this way, with respect to vibration of the drill at the time of cutting the hole (particularly, artificial vibration of the drill for cutting the pilot hole E2 in the method of embodiment 2), the opening edge portion of the hole C, E (the predrilled hole C1 or the straight hole E1) is protected by the head portion 17a of the protective member 17, and damage thereof can be prevented. Therefore, the cut hole E has a good appearance.

The present invention is also applicable to a drill using a cutter head having a blade which is not V-shaped but flat and a cutting point which is protruded at the center thereof. In this case, the same operation and effect as those of the above embodiment can be obtained.

As described above, the drill according to the present invention includes a drill main body and a high-hardness bit attached to a distal end of the drill main body, wherein the bit is attached in an eccentric state in which a center line in a bit width direction is offset to one side in the left-right direction with respect to an axial center of the drill main body, the width dimension of the bit being larger than a diameter dimension of the drill main body.

Further, it is preferable that: the cutter head is a blade portion having a V-shape at a tip of a base plate portion attached to the drill main body and a cutting point at a vertex thereof, and is attached to the drill main body in an eccentric state in which the cutting point is deviated to the left and right sides with respect to the axis of the drill main body.

Further, it is preferable that: the side blades are provided on both left and right side edge portions of the blade portion of the cutter head so as to project radially outward from the outer periphery of the drill body, and the side blades are disposed in a state in which the projecting amounts are different due to the eccentricity of the cutting point, so that the side blade having a large projecting amount out of the left and right side blades has a smaller height than the side blade on the other side.

Further, the lower root of the side blade having a small height is preferably formed in an arc shape.

The wall surface protecting member for drilling according to the present invention has a cylindrical portion for fitting in a movable fit manner on the outer periphery of the drill and a head portion for covering the opening edge of a hole cut by the drill.

In the drilling method of the present invention, after a straight pilot hole is cut in a wall body, the bottom surface of the pilot hole is cut by the drill, thereby forming a large bottomed hole having an enlarged bottom.

Another drilling method according to the present invention is a method of forming a large bottomed hole with an enlarged bottom by cutting a straight hole of a desired depth in a wall body with the drill and then continuously vibrating the entire drill radially outward.

In the above drilling method, it is preferable that: a cylindrical wall surface protecting member for drilling with a head is fitted to a drill in a movable fit state, and a large bottomed hole is cut in a state where an opening edge of a hole cut by the drill is covered with a head portion of the protecting member.

In the drill according to the present invention, the cutter head is attached in an eccentric state with respect to the drill main body, and therefore, the cutter head eccentrically rotates by the eccentric amount (rotates while vibrating outward with respect to the main body) at the time of drilling.

Therefore, when the drill bit is rotated in the previously opened straight pre-drilled hole, a large bottomed hole with an enlarged bottom can be drilled.

Alternatively, after a straight hole is cut by the drill, the entire drill is continuously vibrated radially outward to form a large-diameter pilot hole, and a similar large pilot hole can be drilled.

Therefore, when the mechanical fixing work or the chemical fixing work is performed, since the anchor can be firmly fixed by the large bottom hole, the stability of the installation state of the instrument, the structure, or the like can be improved.

Further, since the recesses and projections are formed on the entire circumferential surface of the hole by the eccentric rotation of the bit, the anchor fixing force can be improved.

In the present invention, the shape of the tool bit is not particularly limited, and a tool bit having a V-shaped blade portion is used, and the tool bit is attached in a state where the apex of the blade portion, that is, the cutting point is offset from the axis of the body, whereby the cutting point can be brought into point contact with the bottom surface of the hole, and the resistance to eccentric rotation can be reduced. Therefore, since the cutter head is easily eccentrically rotated, the large bottomed hole can be naturally and smoothly cut.

In addition, the inventors have confirmed that: the side blades are provided on both the left and right sides of the cutter head, and the side blade having a large projection amount from the drill body due to the eccentricity of the cutting point is set to have a smaller height than the side blade on the other side, so that the side blade cuts the circumferential surface of the hole deeply, thereby forming the unevenness of the circumferential surface of the hole remarkably. Therefore, the fixing force of the anchoring part can be further improved by adopting the invention.

In this case, it was also confirmed that: by forming the lower root portion of the side blade having a small height, that is, the portion supporting the load, in an arc shape, the load supporting force of the side blade can be increased, and the side blade can be prevented from being damaged as much as possible.

On the other hand, according to the wall surface protecting member for drilling and the drilling method, the hole opening edge portion of the wall surface can be protected from the vibration of the drill (particularly, the artificial vibration due to the cutting of the large bottomed hole) at the time of cutting the hole by the head portion of the protecting member, and the damage thereof can be prevented. Therefore, the cut hole has an excellent appearance.

Claims (7)

1. A drill bit is characterized in that the drill bit is provided with a drill bit body,

the drill comprises a drill body and a high-hardness cutter head mounted on the top end of the drill body; the cutter head is installed in an eccentric state in which a width dimension is larger than a diameter dimension of the drill main body and a center line in a cutter head width direction is deviated to a left side and a right side with respect to an axial center of the drill main body,

the cutter head is mounted to the drill main body in an eccentric state in which the cutting point is deviated to one side in the left-right direction with respect to the axis of the drill main body,

a blade unit having a blade portion, a cutting edge portion formed on the blade portion, and a side blade protruding radially outward from the outer periphery of the drill body, the side blade having a protruding amount different depending on the eccentricity of a cutting point; the side blade of the left and right side blades, which has the large projection amount, has a height smaller than that of the other side blade.

2. The drill bit of claim 1,

the lower root of the side blade with small height is formed into an arc shape.

3. A wall surface protecting member for drilling, characterized in that,

the drill bit has a cylindrical portion for fitting in a movable fit on the outer periphery of the drill bit according to claim 1 or 2, and a head portion for covering the opening edge of a hole cut by the drill bit.

4. A method for drilling a hole, characterized in that,

after cutting a straight pre-drilled hole in the wall, the bottom surface of the pre-drilled hole is cut by the drill according to claim 1 or 2, thereby forming a large bottomed hole with an enlarged bottom.

5. A method for drilling a hole, characterized in that,

after a straight hole of a desired depth is cut in a wall body by the drill according to claim 1 or 2, the entire drill is vibrated toward the outer peripheral side to cut the straight hole, thereby forming a large bottomed hole having an enlarged bottom.

6. The drilling method according to claim 4,

a cylindrical wall surface protecting member for drilling with a head is fitted to a drill in a movable fit state, and a large-bottomed hole is cut while an opening edge of a hole cut by the drill is covered with a head portion of the protecting member.

7. The drilling method according to claim 5,

a cylindrical wall surface protecting member for drilling with a head is fitted to a drill in a movable fit state, and a large-bottomed hole is cut while an opening edge of a hole cut by the drill is covered with a head portion of the protecting member.