JP2001121493A - Drilling tool and abutting part forming body therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely perform a drilling work by preventing a drilling blade from being when a drilled body is passed through without providing a chip receiving cover with a possibility of being a hindrance of a drilling work. SOLUTION: This drilling tool 1 for drilling a through-hole in a wall material by a pair of independently projecting drilling blades 7 rotating around a center shaft 4 is provided with an abutting flange 23 which is inserted into a cutting groove of the wall material cut by the drilling blades 7 at the time of a drilling, is abutted on an internal surface of the through-hole when the wall material is passed through and is capable of preventing the drilling blades 7 from colliding with the internal surface of the through hole and an abutting piece 24 abutting on a peripheral edge of the through-hole of the wall material to prevent excess pushing than required of the drilling blades 7 into the wall material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piercing tool for piercing a hole in a building wall material and the like, and to an abutting portion forming body thereof. The present invention relates to a piercing tool for preventing the occurrence of a piercing force and a contact portion forming body therefor.

[0002]

2. Description of the Related Art Conventionally, as a piercing tool for piercing a wall material or the like of a building, there is a piercing tool disclosed in Japanese Utility Model Laid-Open No. Hei 6-21811, which is shown in FIG.

[0003] In FIG. 10, a drilling tool 41 has a bar-shaped supporting member 43 attached orthogonally to a main shaft 42 having a center drill 42 a at the tip. The supporting member 43 has a pair of drilling blades 45. A blade body 44 is attached. The blade body 44 has a bolt 46 protruding therefrom, and can be moved along the support member 43 by loosening a nut 47.

[0004]

However, the piercing device 4
In 1, the positioning of the center drill 42 a that has been positioned is released when the drilling blade 45 rotating about the main shaft 42 passes through the body to be drilled such as the wall member 51, so that the momentum at the time of penetration is released. The perforation blade 45 collides with the inner surface 52a of the through hole 52 that has been bored by being swung in the lateral direction due to bounce or the like.
For this reason, the perforation blade 45 may be broken by this collision, which is dangerous.

[0005] In particular, as shown in FIG.
As described in Japanese Patent Application Laid-Open No. 10-42430 by the present applicant,
When the overlapping hole 55 such as a darma hole shown by a two-dot chain line is formed in the wall material 51, the first through hole 55a is formed first, and then the second through hole 55b is formed. In addition, since the drilling blade is easily displaced in the horizontal direction and collides with the inner surface of the existing first through-hole 55a, it is not possible to avoid the risk of breakage of the drilling blade and twisting of the operator's hand by driving the electric drill. .

According to the drilling tool disclosed in Japanese Patent Application Laid-Open No. H10-42430, the chip receiving cover is in pressure contact with the peripheral edge of the through hole 55 even after the drilling blade has penetrated the wall material. Since it is possible to prevent the piercing tool from moving laterally with respect to the through hole 55, it is possible to prevent the piercing blade from colliding with the inner surface of the first through hole 55a and breaking the piercing tool after the penetration. However, since this drill requires a chip receiving cover, the whole drill has a large size, and has a problem that the structure is complicated and the cost is high.

Further, the piercing device described in the above-mentioned Japanese Patent Application Laid-Open No. H10-42430 has no space where the chip receiving cover abuts on the peripheral portion of the through hole 55 to be pierced, and obstacles such as pillars are obstructed. The chip receiving cover projecting from the wall surface is
In the case where it cannot be abutted, the presence of the chip receiving cover often hinders the drilling operation.

Incidentally, Japanese Patent Application Laid-Open No. 6-91417 shown in FIG.
In the piercing tool 48 having the structure disclosed in Japanese Patent Application Laid-Open Publication No. H07-75, a plurality of piercing blades 50 are protruded along the opening edge of the cylindrical core body 49. Since the entire outer peripheral surface serves as a guide and travels straight without being displaced in the lateral direction, the above-described problem does not occur.

However, the perforation blade 50 is extremely expensive, and the replacement of the perforation blade 50 and the like must all be replaced together with the core body 49, which is troublesome and uneconomical. Further, when drilling through holes having different diameters, there is a disadvantage that a plurality of core bodies 49 must be prepared corresponding to the drilling diameter.

Therefore, the present invention provides a piercing tool that can safely work by preventing breakage of a piercing blade when a pierced object is penetrated, without providing a chip receiving cover that may hinder the piercing operation, and a contact tool therefor. It is an object to provide a part forming body.

[0011]

According to a first aspect of the present invention, there is provided a drilling tool wherein one or a plurality of independently protruding drilling blades which rotate about a center axis form a through-hole in a body to be drilled. Wherein the drilling blade is inserted into a cutting groove of the drilled body cut by the drilling blade at the time of drilling, and contacts the inner surface of the through hole when the drilled body penetrates, so that the drilling blade is inserted into the through hole. It is provided with an inner surface contact portion that can prevent collision with the inner surface.

According to a second aspect of the present invention, there is provided a piercing tool wherein one or a plurality of independently protruding piercing blades rotating about a center axis is used to pierce a through-hole in a body to be pierced. Sometimes, the drilling blade is inserted into the cutting groove of the drilled body cut by the drilling blade, and when the drilled body penetrates, the drilling blade comes into contact with the inner surface of the through hole and collides with the inner surface of the through hole. An inner surface contact portion that can be prevented, and a peripheral edge contact portion that contacts the peripheral edge of the through hole of the perforated body to prevent the drilling blade from being pushed into the perforated body by a certain amount or more. .

According to a third aspect of the present invention, there is provided a piercing tool.
Alternatively, at least one of the inner surface abutting portion and the peripheral edge abutting portion according to claim 2 is provided on a separate abutting portion forming body attached to the boring blade or the boring tool main body, and the abutting portion forming body is provided. But,
It is attached so that the position can be adjusted in the longitudinal direction of the center shaft.

According to a fourth aspect of the present invention, there is provided a piercing tool.
At least one of the inner surface abutting portion and the peripheral edge abutting portion according to any one of claims 3 to 3 is provided on a separate abutting portion forming body attached to a boring blade or a boring tool main body, The contact portion forming body includes a holding portion that holds the boring blade and prevents the tilting thereof.

According to a fifth aspect of the present invention, there is provided a piercing tool.
Alternatively, the contact portion forming body according to claim 4 includes a holding portion for holding the drilling blade.

According to a sixth aspect of the present invention, there is provided a piercing tool.
A plurality of perforation blades according to any one of claims 5 to 5,
They are connected to each other by the one contact portion forming body.

According to a seventh aspect of the present invention, there is provided a piercing tool.
The inner surface contact portion according to any one of claims 6 to 6 is formed on an arc-shaped plate that stands upright in the axial direction with the same radius of curvature as the cutting groove cut by the drilling blade.

The piercing tool according to the invention of claim 8 is the piercing tool according to claim 3.
The contact portion forming body according to any one of claims 7 to 7,
It is formed of a metal plate through which the center shaft passes.

According to the ninth aspect of the present invention, there is provided a piercing tool.
9. The center shaft according to any one of claims 8 to 8, which is urged forward and backward, and is pressed by the pierced body while being positioned on the pierced body, thereby penetrating the pierced body. It retreats without.

According to a tenth aspect of the present invention, there is provided an abutting portion forming body for a piercing tool, wherein one or a plurality of independently protruding piercing blades or a piercing tool body which rotates about the center axis of the piercing tool are axially positioned. Adjustably attached, inserted into the cutting groove of the pierced body cut by the piercing blade at the time of piercing, when the piercing body penetrates, it comes into contact with the inner surface of the through-hole, the piercing blade is the It is provided with an inner surface contact portion that can prevent collision with the inner surface.

According to an eleventh aspect of the present invention, there is provided an abutting portion forming body for a piercing tool, wherein one or a plurality of independently protruding piercing blades or a piercing tool body which rotates about a center axis of the piercing tool are axially positioned. Adjustably attached, inserted into the cutting groove of the pierced body cut by the piercing blade at the time of piercing, when the piercing body penetrates, it comes into contact with the inner surface of the through-hole, the piercing blade is the An inner surface abutting portion capable of preventing collision with an inner surface, and a peripheral edge abutting portion which abuts on a peripheral edge of the through hole of the perforated body to prevent the drilling blade from being pushed into the perforated body by a certain amount or more. It is provided with.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In the figure, a shank shaft 3 is inserted through a central through hole 2a of a piercing tool main body 2 integrally formed of a synthetic resin or the like, and a center shaft 4 is inserted into the shank shaft 3 from one end side. It is inserted and retracted in the axial direction. The shank shaft 3 is, as shown in FIG.
At one end, a mounting portion 3a is formed, which is removably inserted into a rotary driving body (not shown). The other end is open, and the coil spring 5 shown in FIG. A spring accommodating portion 3b is formed. Further, as shown in FIG.
A detent sleeve 3c for preventing the center shaft 4 from rotating around the axis is formed in the inner surface of the spring accommodating portion 3b in the axial direction. As shown in FIG. 7, the center shaft 4 is provided with a center drill 6 in a round hole 4a provided at the distal end.
The circular tube 4b is forcibly fitted to the rear end, and two corrugated spring pins 4c are pressed into the circular tube 4b in the radial direction. A part of the center shaft 4 is a spring housing 3 of the shank shaft 3.
In the state inserted into the inside of the shank shaft 3, one side surface of the circular tube 4 b can move in the axial direction against the biasing force of the spring 5 extending in the axial direction. The protrusion from the shank shaft 3 to the outside is prevented by abutting on one side surface of the C-shaped stop ring 4d fitted in the annular groove 3d formed in the groove.

As shown in FIGS. 1 to 3, a pair of rectangular parallelepiped blade holders 8 for holding one end of a drilling blade 7 are attached to the left and right sides of the bottom surface 2b formed on the drilling side of the drilling tool main body 2. Have been. The blade holder 8 has a long hole 8a passing therethrough.
A bolt 9 is inserted through the piercing tool main body 2.
By being screwed to a nut 10 embedded in the shaft, the motor is mounted to be movable by a predetermined distance in a direction perpendicular to the axis. This is such that the distance from the axis to the perforation blade 7, that is, the perforation radius can be changed and adjusted to correspond to the plurality of through holes 52 having different diameters. In this case, the distance from the axis to each of the drilling blades 7 is naturally adjusted to be the same.
A parallel groove 8b, which is slightly shallower than the plate thickness of the drilling blade 7, is formed in the outer surface of the blade holder 8 in the axial direction. At the approximate center of the outer surface of the blade holder 8, a locking projection 8c slightly protruding outward is provided, while one end of the drilling blade 7 is engaged with the locking projection 8c. A locking hole 7a for stopping is provided. Therefore, after the perforation blade 7 is fitted into the parallel groove 8b of the holding table 8 and the locking hole 7a of the perforation blade 7 is locked to the locking projection 8c of the blade holding table 8, the left and right edges are The screw 11 is fastened so that one end is held at a fixed position between the blade holder 8 and the head of the screw 11.

In the first aspect, the "independently protruding perforating blade" means a perforating blade whose one end is held by the blade holder 8 and is erected on the wall material 51 side. A perforation blade formed integrally with the core body 49 along the outer periphery of the distal end portion of the core body 49 such as the conventional perforation blade 50 shown in FIG.

8 and 9, a contact plate 21 formed by pressing a metal plate material is disposed on the center shaft 4 so as to be movable perpendicularly to the center shaft 4 passing therethrough. I have. The abutment plate 21 is a feature of the present invention, and has a substantially disk shape. At a position where a peripheral end of the abutment plate 21 is opposed, a pair of mounting flanges 22 are bent at right angles to the punch body 2 side. I have.

At a plurality of other portions at the peripheral end of the contact plate 21, contact flanges 23 bent at right angles to the through holes to be drilled are formed along the outer peripheral arc. It is formed. Therefore, the contact flange 23 also has a free end surface having an arc shape having the same radius of curvature as the outer periphery of the flat portion of the contact plate 21. The height of the contact flange 23 is determined by moving the contact plate 21 from the wall material 51.
Is formed smaller than the protruding length of the piercing blade 7 protruding in the direction of. The contact flange 23 corresponds to an inner surface contact portion in the claims.

Furthermore, a radially protruding portion is provided between the mounting flange 22 and the abutting flange 23 at the peripheral end of the abutting plate 21, and comes into planar contact with the peripheral edge of the through hole 52 at the time of drilling. A contact piece 24 is formed. The contact piece 24 is formed on an inclined surface slightly curved toward the punch body 2 with the outer end of the flat portion of the contact plate 21 as a base end. The contact piece 24 corresponds to a peripheral contact part in the claims.

At the center of the plane of the contact plate 21, an insertion hole 25 through which the center shaft 4 is inserted is formed, and a pair of mounting holes 26 are formed at a predetermined distance from the center of the plane. An attachment rod 27 having a screw hole on the contact end side is in contact with the back side surface of the mounting hole 26, and an attachment screw 28 is screwed into the screw hole from the other side surface of the contact plate 21. It is integrally attached to the contact plate 21.
The other end of the mounting rod 27 is movably inserted into a through hole 2 c provided in the piercing tool main body 2. The mounting rod 27
Together with the piercing blade 7 holds the contact plate 21 in parallel with the piercing tool main body 2 at a predetermined distance from the bottom surface 2b.

Further, a weld nut 29 is welded and attached to the surface of the mounting plate 22 on the center shaft 4 side of the mounting plate 22, and the perforated blade 7 is abutted on the outer surface of the mounting flange 22. The blade holding piece 30 is abutted from the outside thereof and two screws 31 are screwed into the weld nut 29 so that the mounting flange 22 and the blade holding piece 30 form a substantially intermediate portion in the longitudinal direction of the drilling blade 7. Is to be clamped. That is, speaking from the contact plate 21 side, the contact plate 21 loosens the screw 31 and moves in the axial direction, and one end of the contact plate 21 has an arbitrary height with respect to the perforated blade 7 attached to the blade holder 8. It has come to be supported by. Thus, the length of the perforation blade 7 protruding from the contact plate 21 toward the through hole 52 is arbitrarily adjusted according to the thickness of the wall material 51. In addition, it is possible to prevent the shaft from being bent or displaced laterally, particularly toward the inner side of the shaft when drilling.

The piercing blade 7 is provided with a through-hole 52 to be pierced.
The distance from the shaft center can be adjusted appropriately in accordance with the inner diameter of a plurality of holes, and a plurality of types of contact plates 21 arranged between the pair of punching blades 7 having different diameters are prepared accordingly.

Next, a description will be given of an operation of providing a through-hole using the punch having the above-described configuration according to the present embodiment.

First, although not shown, a magnet attached to the front surface of a wiring box disposed behind a wall is detected using a magnetic detector, and the center of a through hole 52 having a predetermined diameter to be drilled is detected. decide. Next, the bolt 9 of the blade holder 8 of the drilling tool 1 is loosened according to the size of the through hole 52, and the blade holder 8 is moved in the lateral direction to be held at a predetermined position.
The perforation blade 7 is attached to the outer surface of the blade holder 8 via the first blade holder 1. Then, the contact plate 21 that matches the interval between the pair of attached punching blades 7 is selected, and the mounting plate 22 is sandwiched between the mounting flange 22 and the blade holding piece 30 so that the contact plate 21 is punched. It is held at a predetermined distance from the bottom surface 2b of the main body 2. At this time, the distance separating the contact plate 21 from the bottom surface 2b is determined by the distance of the contact plate 21.
The length of the drilling blade 7 protruding from the through hole 52 to the through hole 52 side is adjusted to a size suitable for the thickness of the wall material.

When the distance between the pair of piercing blades 7 of the piercing tool 1 is adjusted in this way and the holding height of the contact plate 21 is adjusted, the center drill 6 of the piercing tool 1 is brought into contact with the center of the piercing tool. Touch and start drilling. Here, the center drill 6 of the center shaft 4 gradually receives a larger reaction force from the wall member 51 with the drilling, but the spring 5 that is biased in the axial direction is housed in the spring housing portion 3b of the shank shaft 3. Therefore, when a certain or more pressing force is applied, the spring retracts to the inner side of the spring accommodating portion 3b. Therefore, the center drill 6 does not pierce the wall material 51, and its tip stops partially embedded in the wall material.
The center shaft 4 is always stably held at a fixed position. Thus, the wiring box 53, cables, wiring equipment, and the like on the back of the wall are prevented from being damaged due to the center drill 6 punching out the wall material 51, and are protected.

Next, when the tip of the piercing blade 7 reaches the surface of the wall member 51, piercing is started by the piercing blade 7.
Then, when cutting proceeds to a certain depth of cut, FIG.
As shown in FIG. 7, the tip of the contact flange 23 of the contact plate 21 reaches the surface of the wall material 51 and thereafter fits into the narrow cutting groove 5 of the wall material 51 cut by the perforation blade 7.

At this time, since the piercing blade 7 is formed in a flat plate shape having a predetermined width, if it is rotated, the width of the cutting groove S is inevitably larger than the thickness of the piercing blade 7 by the amount of protrusion at both ends of the outer surface. Become. On the other hand, since the contact flange 23 is formed in an arc shape, the width of the track drawn by rotation always matches the plate thickness of the contact flange 23. That is, if this is shown in FIG. 5, the outer diameter R3 of the contact flange 23 is the radius R1 to both ends P1 of the outer surface of the drilling blade 7 forming the outer diameter of the cutting groove S.
In addition, the inner diameter R4 of the contact flange 23 is smaller than the radius R2 to the inner surface center portion P2 of the drilling blade 7 forming the inner diameter of the cutting groove S, that is, R1>R3>R4> R.
There is a relationship of 2. Therefore, since the contact flange 23 of the contact plate 21 is always located in the narrow cutting groove S cut by the drilling blade 7, the contact flange 23 is
Is strongly slid on the inner surface 52a of the through hole 52 and is inserted into the cutting groove S without receiving a large resistance.

As a result, immediately before the wall material 51 is cut and punched, the outer surface of the contact flange 23 is formed with a through hole 52.
Are merely in contact with the inner surface 52a or are separated by a very small gap. For this reason, even if the through hole 52 is punched out and the positioning of the center drill 6 is released, the perforation blade 7 is guided by the contact flange 23 of the contact plate 21 and moves through the through hole 52 without being shaken in the lateral direction. The piercing blade 7 moves straight and is prevented from colliding with the inner surface 52a of the through hole 52 in the lateral direction due to the moment of penetration. The free end sides of the pair of opposing punching blades 7 are located at substantially middle portions in the longitudinal direction.
It is connected and held by two contact plates 21.
From these facts, since the pair of perforation blades 7 do not break due to the impact at the time of collision, the risk of injury by the perforation blades 7 can be avoided. Further, the lateral movement of the drilling blade 7 is regulated by the contact plate 21, and the drilling blade 7 is held at a fixed position while being prevented from flexing to the side, particularly to the shaft side, at the time of drilling. Can be.

Immediately after punching the through hole 52, the abutment piece 24 of the abutment plate 21 abuts against a flat portion of the periphery of the through hole 52. Is prevented from fitting into the through hole 52. For this reason, the perforation blade 7 is fitted into the wiring box with the force of punching the wall material 51, and the distal end may damage or break the wiring box 53 or the cables and wiring equipment in the wiring box 53 at the tip. Is prevented.

Here, since the contact piece 24 is slightly curved toward the piercing tool main body 2 with the outer periphery as a boundary, only the bent portion of the contact piece 24 contacts the peripheral flat surface of the through hole after the penetration. The portion on the free end side of the contact hole is slightly separated from the peripheral flat portion of the through hole 52 toward the piercing tool main body 2. For this reason, if the contact piece 24 is completely flush with the disc portion of the contact plate 21 without slightly warping the punch body 2 side,
Since the entire contact piece 24 is strongly pressed against the plane portion of the peripheral edge of the through hole 52, a great amount of sliding resistance is received until the rotation is stopped after the penetration, but the contact piece 24 of the present application slightly perforates. Since it is curved toward the tool body 2 and the contact area between the contact piece 24 and the plane portion of the periphery of the through hole 52 is small, the sliding resistance generated with the rotation is small. Therefore, the load applied to the operator and the tool during the operation is reduced, and the operation can be performed safely and easily, and the tool is prevented from being damaged. In addition, the generation of scratches on the plane portion of the peripheral edge of the through hole 52 is prevented.

Here, the drilling tool 1 adjusts the mounting height of the contact plate 21 by loosening the screw 31, and minimizes the length of the projecting blade 7 from the contact plate 21 for cutting the wall material 51. By adjusting the length to the required length, it is possible to perforate a desired wall thickness.

As described above, the piercing tool according to the present embodiment comprises a pair of independently projecting piercing blades 7 that rotate about the center shaft 4.
Thereby, the through hole 52 is formed in the wall material 51,
The wall material 51 cut by the perforation blade 7 at the time of perforation
An inner surface abutment that can be inserted into the cutting groove S to abut the inner surface 52a of the through hole 52 when the wall material 51 penetrates and prevent the drilling blade 7 from colliding with the inner surface 52a of the through hole 52. Contact flange 23 as a part, and through-hole 5 of said wall material 51
Abutment piece 2 as an abutment portion for abutting against the peripheral edge of No. 2 to prevent the perforated blade 7 from being pushed into the wall material 51 by a certain amount or more.
4 is provided.

Accordingly, the wall material 5 which is the body to be drilled can be provided without providing a chip receiving cover which may be an obstacle to the drilling operation.
It is possible to prevent the drilling blade 7 from being damaged at the time of penetration of 1 and to perform the drilling operation safely.

Incidentally, the contact plate 21 as the contact portion forming body of the present embodiment is attached to the drilling blade 7 via the blade holding piece 30 by tightening the screw 31.
The invention is not limited to this, and various attachment means can be adopted. For example, the attachment rod 27 may be fixed to a fixed position of the piercing tool main body 2 so as to be directly attached to the piercing tool main body 2 via the attachment rod 27. When the contact plate 21 is attached to the piercing tool main body 2, the contact plate 21 is also attached to the piercing blade 7, or simply
It is also possible to adopt a structure that only holds the movable member in the axial direction. Even when the abutment plate 21 is merely movably held by the perforation blade 7, the perforation blade 7 is restricted from moving laterally by the abutment plate 21 and the blade holding piece 30 serving as a guide. Since bending to the side, especially to the shaft side, is prevented, the piercing blade 7 can be held at a fixed position, the dimensional accuracy of the through hole 52 can be improved, and the piercing blade 7 can be prevented from being broken.

In addition, the contact plate 21 of each of the above embodiments is used.
Is formed of a single plate and attached to the pair of perforation blades 7 to connect the perforation blades 7 to each other. However, the present invention is not limited to this. The abutment plate 21 may be individually attached for each of the seven. However, if the abutment plate 21 is formed of one piece and connects the perforation blade 7, the perforation blade 7 can be more firmly held at a fixed position.

The inner contact portion provided on the contact plate 21 is formed by an arc-shaped contact flange 23.
However, the present invention is not limited to this.
A pin-shaped body may be erected in the peripheral direction of the first member in the axial direction.

Further, in each of the above embodiments, the contact flange 23 as the inner surface contact portion and the contact piece 24 as the peripheral edge contact portion according to the present invention are provided separately from the punch body 2. Although provided on the plate 21, the inner surface contact portion and the peripheral edge contact portion described in the claims may be provided integrally with the punch body 2.

In addition, in the above embodiment, the present invention is applied to a piercing tool provided with a pair of piercing blades 7. However, the present invention is not limited to this, and three or more piercing blades 7 are provided and applied to this piercing tool. You can also.

[0048]

As described above, the piercing device of the present invention has a through hole formed in a body to be pierced by one or a plurality of independently protruding piercing blades rotating about a center axis. The drilling blade is inserted into the cutting groove of the drilled body cut by the drilling blade at the time of drilling, and when the drilled body penetrates, the drilling blade comes into contact with the inner surface of the through-hole and collides with the inner surface of the through-hole. This is provided with an inner surface abutting portion which can prevent the contact.
Therefore, it is possible to prevent the drilling blade from being damaged when the drilled body penetrates, and to perform the drilling operation safely without providing a chip receiving cover that may hinder the drilling operation.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a punch according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of the punch of FIG. 1;

FIG. 3 is a side view of the punch of FIG. 1;

FIG. 4 is a bottom view of the punch of FIG. 1;

FIG. 5 is an explanatory view showing a positional relationship of a contact flange in a cutting groove cut by the drilling blade of FIG. 4;

FIG. 6 is a partially cutaway front view of the shank shaft of FIG. 1;

FIG. 7 is a longitudinal sectional view of the center axis of FIG. 1;

FIG. 8 is a perspective view of the contact plate of FIG. 1;

FIG. 9 is a front view of the contact plate of FIG. 8;

FIG. 10 is a front view showing a conventional punch.

FIG. 11 is a front view showing a polymerization hole formed in a wall material.

FIG. 12 is a front view showing another conventional perforator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 drilling tool 2 drilling tool main body 4 center shaft 7 drilling blade 21 contact plate 22 mounting flange 23 contact flange 24 contact piece 29 weld nut 30 blade holding piece 31 screw 51 wall material 52 through hole 52a inner surface S cutting groove

Claims (11)

[Claims] 1. A piercing tool for piercing a hole in a body to be pierced by one or a plurality of independently protruding piercing blades rotating about a center axis, the piercing tool being cut by the piercing blade at the time of piercing. An inner surface contact portion which is inserted into a cutting groove of the body to be pierced and which can contact the inner surface of the through hole when the body to be pierced to prevent the piercing blade from colliding with the inner surface of the through hole. A piercing tool comprising: 2. A piercing tool for piercing a hole in a body to be pierced by one or a plurality of independently protruding piercing blades rotating about a center axis, wherein the piercing tool is cut by the piercing blade at the time of piercing. An inner surface contact portion that is inserted into the cutting groove of the body to be pierced and that can contact the inner surface of the through hole when the body to be pierced to prevent the piercing blade from colliding with the inner surface of the through hole; A piercing tool, comprising: a peripheral edge contact portion that abuts on a peripheral edge of a through hole of the body to be pierced to prevent the piercing blade from being pushed into the body to be pierced more than a predetermined amount. 3. At least one of the inner surface contact portion and the peripheral edge contact portion is provided on a separate contact portion forming body attached to the drilling blade or the piercing tool main body, and the contact portion forming body is provided. Is
The piercing tool according to claim 1 or 2, wherein the piercing tool is attached so as to be adjustable in the longitudinal direction of the center axis. 4. At least one of the inner surface abutting portion and the peripheral edge abutting portion is provided on a separate abutting portion forming body attached to the boring blade or the piercing tool main body, and the abutting portion forming body is provided. Is
4. A holding part for holding the drilling blade and preventing its tilting is provided.
A piercing tool according to the item. 5. The piercing device according to claim 3, wherein the contact portion forming body includes a holding portion for holding the piercing blade. 6. The piercing device according to claim 3, wherein the plurality of piercing blades are connected to each other by one contact portion forming body. 7. The inner surface abutting portion is formed in an arc-shaped plate that stands upright in the axial direction with the same radius of curvature as a cutting groove cut by the drilling blade. The piercing device according to any one of claims 6 to 10. 8. The perforator according to claim 3, wherein the contact portion forming body is formed of a metal plate through which the center shaft passes. 9. The center shaft is urged to move forward and backward,
9. The device according to claim 1, wherein the body is retracted without penetrating the body to be pierced by being pressed by the body to be pierced while being positioned on the body to be pierced. 10. The piercing device as described. 10. A piercing tool which is rotatably mounted on one or a plurality of independently protruding piercing blades or a piercing tool body which rotates about a center axis of the piercing tool in an axial direction, and is cut by the piercing blade at the time of piercing. An inner surface contact portion which is inserted into a cutting groove of the drilled body, and which can abut the inner surface of the through hole when the drilled body penetrates to prevent the drilling blade from colliding with the inner surface of the through hole. A contact part forming body for a piercing tool. 11. A piercing tool is mounted on one or more independently protruding piercing blades or piercing tool main bodies rotating about a center axis of the piercing tool so as to be axially adjustable in position in the axial direction, and is cut by the piercing blade at the time of piercing. An inner surface contact portion that is inserted into the cutting groove of the pierced body, and that can abut the inner surface of the through hole when the pierced body penetrates to prevent the piercing blade from colliding with the inner surface of the through hole. Forming a contact portion of the piercing tool, comprising: a peripheral contact portion that contacts the peripheral edge of the through-hole of the drilled body to prevent the drilling blade from being pushed into the drilled body by a certain amount or more. body.