JPH1034406A - Boring tool and forming method of bottom expansion hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boring tool and the forming method of a bottom expansion hole by which the depth of the bottom expansion hole can be changed and also the space volume of the bottom expansion hole can be enlarged. SOLUTION: An edge supported 2 is inserted in a cylindrical tool main body 1 in which double spiral slits 1a, 1b are installed on a side surface part and a pair of edges 3 constituted turnably in the longitudinal direction of the tool main body 1 are installed on the tip of an edge supporter 2. The tip of a boring tool A is inserted into a prepared hole 4a and when the tool main body 1 is rotated and a guide pin 2g projected on a diagonal line on the side surface part of the edge supporter 2 is engaged with the spiral slits 1a, 1b of the tool main body 1 and the tool main body 1 is carried out a spiral motion and a slide operation for the edge supporter 2, a pair of edges 3 are opened and a dome shape bottom expansion hole 5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is required when a chemical anchor is fixed by injecting an expansion anchor or a chemical into a relatively soft member such as lightweight concrete such as ALC, wood, rubber, plastic or the like. The present invention relates to a boring tool for forming a widened bottom hole and a method of forming a widened bottom hole using the same.

[0002]

2. Description of the Related Art As a conventional boring tool for forming an enlarged bottom hole, the technology disclosed in Japanese Patent Application Laid-Open No. 4-360702 is shown in FIG.
This will be described with reference to (a) and (b). This tool is shown in FIG.
As shown in (a), a pair of blades 51 formed in a scissor shape is supported by a support shaft 54 in a small diameter portion 53 of an outer cylinder 52, and a hypotenuse 56 of a projection 55 formed at one end of the blade 51. Further, an operating member 58 provided at the tip of a support rod 57 fitted from the other end of the outer cylinder 52 is engaged.

[0003] Then, an electric drill or the like (not shown) is used in FIG.
(B) is connected to the connecting portion 57a at the base end of the support rod 57,
The outer cylinder 52 is inserted into the base hole 60 formed beforehand using an electric drill or the like until the distal end surface 61a of the contact member 61 contacts the surface 59a of the base 59. Then, by rotating the electric drill to push the support rod 57 while integrally rotating the support rod 57, the outer cylinder 52 and the blade 51, the action member 58 is formed on the hypotenuse of the projection 55 formed at one end of the blade 51. 6B, the tip of the blade 51 is opened, and a predetermined position of the base hole 60 is excavated to form a truncated cone-shaped enlarged portion 62, as shown in FIG. 6B.

[0004]

However, according to the above-mentioned prior art, a pair of blades 51 formed like scissors with the tip end surface 61a of the contact member 61 in contact with the surface 59a of the base 59.
Is opened to form a truncated cone-shaped enlarged portion 62, so that the depth position of the blade 51 when forming the enlarged portion 62 is constant, so that the depth of the enlarged portion 62 can be changed. Can not. In addition, since it is composed of many parts, the cost of parts is increased, and since the structure is complicated, it takes time to assemble the boring tool.

Further, since the enlarged portion 62 has a truncated cone shape,
There is a problem that the space volume of the enlarged portion 62 becomes relatively small, and a sufficient space cannot be secured when the chemical anchor is fixed by injecting the expansion anchor or the medicine.

[0006] The present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a boring tool and a method for forming a bottom-opening hole which can change the depth of the bottom-opening hole and can increase the space volume of the bottom-opening hole.

[0007]

A boring tool according to the present invention for achieving the above object has a grip portion of a rotating means at one end, and has a cylindrical shape from the other end to at least an intermediate portion. A tool body having a double helical slit in the cylindrical portion, a blade support fitted and slidably fitted to the cylindrical portion of the tool body with its tip protruding, and the blade support A pair of blades coaxially supported at the tip of the blade support, and a pair of guide pins guided by a slit of the tool body project diagonally from a side surface of the blade support. I do.

In the above configuration, the blade support fitted into the cylindrical portion of the tool body spirally moves along the spiral slit (progresses / retreats while rotating) due to the engagement between the guide pin and the spiral slit. A pair of blades rotatably supported by the tip of the blade support are slidable with respect to the tool body in accordance with the amount of protrusion of the blade support from the tool body end. The amount radially protruding from the side surface varies in an arc about the axis of the blade.

That is, when the protruding amount of the blade support from the tool main body is maximum, the blade is rotatable to the tool main body side and the opposite side (tip side) to the tool main body, and along the longitudinal direction of the blade support. When the blade support is protruded from the tool body at a minimum when the blade support is protruded from the tool body in a substantially linear manner, the blade is opened at right angles to the longitudinal direction of the tool body and opposite to the tool body (tip) Side) along the longitudinal direction of the blade support, and can be pivoted to a state where the blade support is closed substantially linearly and closed.

[0010] The method of forming a widened bottom hole according to the present invention is characterized in that:
A pilot hole is drilled in the workpiece to be boring, and the boring tool is inserted into the pilot hole in a state where the tips of the pair of blades are folded back toward the tool main body, and the tool main body is rotated by rotating means. And the blade is expanded to form a widened hole in the workpiece.

According to the above configuration, first, a pilot hole is formed in a workpiece to be boring, and then a grip portion at an end of the tool body is gripped by a rotating means such as an electric drill. Then, insert the above-mentioned boring tool into the prepared hole of the workpiece in a state where the protruding amount of the blade support from the tool main body is maximized, and the tips of the pair of blades are folded back toward the tool main body and overlapped and closed. Then, the tip of the blade support is brought into contact with the bottom of the pilot hole. Then, the tool body gripped by rotating means such as an electric drill is rotationally driven in a predetermined direction (the same direction as the spiral of the slit with respect to the traveling direction).

At the time of cutting, the frictional force received from the bottom of the prepared hole by the blade support having its tip abutting on the bottom of the prepared hole, or the blade is hooked and locked on the side wall surface of the prepared hole. Thus, a resistance acts on the blade, and the rotation of the blade support is suppressed. The rotation of the blade support is slower than the rotation of the tool body due to the frictional force and the resistance.

On the other hand, the guide pin protruding from the blade support is engaged with a spiral slit formed in the tool body, and the frictional force and the resistance force are transmitted from the guide pin to the spiral slit. Since the tool body is rotating while being pushed in, the guide pin moves along the spiral slit from the front end to the rear end of the spiral slit, and the frictional force is increased. And can escape the resistance.

By the above movement, the tool body slides with respect to the blade support while making a spiral motion in the direction of the blade (the traveling direction). At this time, the tip of the cylindrical portion of the tool body abuts and slides on the curved portion of the blade, and the blade rotates around an axis provided at the tip of the blade support to open the tool while drawing an arc. The blade is rotated later than the rotation of the main body, and the side wall of the prepared hole is excavated in an arc shape by the blade.

In particular, since the slit for engaging the guide pin is formed in a spiral shape, the resistance force applied to the blade during cutting can be smoothly released to the slit of the tool body via the guide pin of the blade support. And the blade can be opened smoothly.

When the amount of protrusion of the blade support from the tool body is minimized, the blade is opened perpendicular to the tool body, and the straight portion of the blade reaches the bottom of the pilot hole, A dome-shaped (hemispherical) expanded bottom hole is formed at the bottom of the pilot hole.

Here, by further pushing the tool body while rotating it against the workpiece, the depth of the dome-shaped enlarged hole is further increased by the straight portion of the blade opened perpendicular to the tool body. It can be extended to form a bell-shaped bottom hole.

After the predetermined bottom-extending hole is formed, when the rotation of the rotating means is stopped and the tool body is pulled out from the bottom-extending hole, the curved portion of the blade comes into contact with the inlet-side curved surface portion of the workpiece having the bottom-extending hole. By sliding, the blade is closed on the opposite side (tip side) of the tool body substantially linearly along the longitudinal direction of the blade support, and can be pulled out from the workpiece having the enlarged bottom hole.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a boring tool and a method for forming a bottom-extending hole according to the present invention will be specifically described with reference to the drawings. 1 is an explanatory side sectional view showing a configuration of a boring tool according to the present invention, FIG. 2 (a) is an explanatory side sectional view showing a configuration of a cylindrical tool body, and FIG. 2 (b) is a tool body. 2 (c) is a view for explaining the configuration of a double spiral slit provided on the side of the tool body, FIG. 3 (a) is a plan view showing the configuration of the blade support, FIG. 3B is a front view showing the configuration of the blade support, FIG. 4C is a front view showing the shape of the blade used as a pair, FIG. 4D is a side view showing the configuration of the guide pin, and FIG. ) Shows a state in which a prepared hole is formed in the workpiece, FIG. 4B shows a state in which the boring tool according to the present invention is inserted into the prepared hole, and FIG. FIG. 4D shows a state in which a dome-shaped bottom hole is formed by the boring tool, FIG. 4D shows a state in which the boring tool according to the present invention is pulled out from the bottom hole, and FIG. By extending the depth of the hole is a diagram showing a state of forming a bell-shaped 拡底 hole.

First, the configuration of a boring tool according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a view showing the entire configuration of a boring tool A according to the present invention, in which a cylindrical blade-shaped support body 2 is inserted into a tool body 1 having a cylindrical shape, with a tip end protruding and sliding. A pair of blades 3 are coaxially and rotatably supported at the tip of the blade support 2 so as to be freely fitted.

FIGS. 2 and 3 show the construction of each component constituting the boring tool A. FIG. As shown in FIGS. 1 and 2 (a) and 2 (b), the tool main body 1 is formed in a cylindrical shape over the entirety, and for example, has a total length of 100 mm, an outer diameter of 10 mm, and an inner diameter of 8 mm.
And made of a material such as stainless steel.

At a substantially central portion of the tool body 1, FIG.
As shown in (c), a pair of double spiral slits 1a, 1
b, and the spiral slits 1a, 1b are
It is formed in a clockwise spiral curve from right to left in FIG.

[0023] In the longitudinal direction of the tool body 1, a spiral slit 1a, the width L ₁ of 1b has been formed, FIG. 3
In the longitudinal direction of the blade 3 shown in (c) are formed corresponding to the length L _2, the length dimension in the longitudinal direction of the blade 3 L
₂ is set corresponding to the size of the outer diameter of the dome-shaped enlarged bottom hole 5 shown in FIG. In the present embodiment, it constitutes a longitudinal direction of the length dimension L ₂ of the blade 3 to 20 mm.

The blade support 2 shown in FIGS. 3 (a) and 3 (b)
The outer diameter corresponds to the inner diameter of the tool body 1 and is made of a material such as stainless steel in a cylindrical shape having an outer diameter slightly smaller than the inner diameter, and the blade support 2 is inserted into the tool body 1 and slides. It is free.

At the tip of the blade support 2, a blade receiving slit 2 a having a size corresponding to the length L ₂ of the blade 3 in the longitudinal direction and formed in the length direction of the blade support 2 is provided. Provided,
At the end of the blade receiving slit 2a on the blade support 2 body side,
An inclined surface 2b corresponding to the shape of the curved portion 3a of the blade 3 is formed.

A hole 2d is formed in the tip end of the pair of blade supports 2c separated by the blade accommodating slit 2a of the blade support 2 in the radial direction of the blade support 2, and is inserted into the hole 2d. The pair of blades 3 are coaxially rotatably supported by the fixing pins 2e (see FIG. 1).

At the rear end of the blade support 2, a hole 2 f is formed in the radial direction of the blade support 2, and diagonally from the outside of the side surface of the tool body 1 through the spiral slits 1 a and 1 b. A pair of guide pins 2g shown in FIG. 3D are fitted into the holes 2f, fixed and protruded. The guide pin 2g is
For example, it is formed of a 2.6 × 8 screw or the like, and can be screwed into the screw hole 2f and protruded.

As a result, the pair of guide pins 2g move along the helical slits 1a and 1b, so that the blade support 2 moves in a spiral motion with respect to the tool body 1 (progressing while rotating). fall back).

As shown in FIG. 3C, the pair of blades 3 rotatably supported on the blade support 2 has a curved portion 3a and a straight portion 3b, and the tip 3d has a curved portion 3a. The blade 3 has a sharpened shape, and a hole 3c is formed at the rear end of the blade 3. Then, two blades 3 are inserted in the blade accommodation slit 2a of the blade support 2.
By inserting the fixing pin 2e into the hole 3c of each blade 3 and the hole 2d of the blade supporting portion 2c through the fixing pin 2e, and fixing the fixing pin 2e to the blade supporting portion 2c. As shown in FIG. 1, a pair of blades 3 are rotatably supported on the blade support 2 in opposite directions.

Using the boring tool A constructed as described above, lightweight concrete such as an ALC panel, wood, rubber,
A method of forming the enlarged bottom hole 5 in the workpiece 4 made of a relatively soft member such as plastic will be described in detail with reference to FIGS.

First, as shown in FIG.
A prepared hole 4a having a predetermined depth is formed in the workpiece 4 with a 10 mm drill tooth 6 gripped by an electric drill.

The rear end of the tool body 1 of the boring tool A is a gripping portion 1c which is gripped by a chuck such as an electric drill as a rotating means. To grip.

On the other hand, in the pair of blades 3 of the boring tool A, the guide pins 2g are located at the distal end portions 1a1 and 1b1 of the spiral slits 1a and 1b, and the blade support 2 projects maximum from the tool body 1. In this state, the pair of blades 3 are rotatable about 360 ° with respect to the blade support 2, and the pair of blades 3 are in the state shown in FIG.
That is, the tip 3d of the pair of blades 3 is folded back toward the tool main body 1 side, overlapped and closed, and gripped by an electric drill in a state where the curved portion 3a of the blade 3 is in contact with the inclined surface 2b of the blade support 2. The boring tool A is inserted into the prepared hole 4a formed in the workpiece 4, and the tip 2 of the blade support 2c of the blade support 2 is inserted into the bottom surface 4b of the prepared hole 4a.
h.

Next, the tool body 1 gripped by a chuck of an electric drill (not shown) is directed from right to left in FIG. 4B (direction in which the boring tool A is pushed into the prepared hole 4a of the workpiece 4). Tool body 1 by turning it clockwise.
And the blade support 2 attempts to rotate clockwise in the traveling direction (from right to left in FIG. 4B).

At this time, the frictional force that the tip 2h of the blade support portion 2c of the blade support 2 receives from the bottom surface 4b of the pilot hole 4a, or
The rotation of the blade support 2 is suppressed by the resistance force by which the blade 3 is hooked and locked on the side wall surface 4c of the prepared hole 4a of the workpiece 4. The rotation of the blade support 2 is slower than the rotation of the tool body 1 due to these frictional forces and resistances.

The frictional force and the resistance force are transmitted from the guide pin 2g to the spiral slits 1a and 1b.
Is rotating while being pushed in, so the guide pin 2g
Are along the spiral slits 1a, 1b from the front end 1a1, 1b1 of the spiral slits 1a, 1b to the rear end 1a2.
, 1b2. By this spiral movement,
The frictional force and the resistance force can be released.

Then, the tool body 1 rotates clockwise with respect to the blade support 2 whose rotation has been suppressed in the traveling direction (from right to left in FIG. 4B), and the helical slits 1a,
By the engagement of the guide pin 1g and the guide pin 2g, the tool main body 1 performs a spiral motion with respect to the blade support 2 while rotating clockwise from right to left in FIG. 4B.

At this time, the tip 1d of the tool body 1 moves to the left in FIG. 4C with respect to the blade support 2 while abutting on the respective curved portions 3a of the pair of blades 3, whereby the pair of blades 3 is moved. 4c rotates clockwise from right to left in FIG. 4 (c) while rotating leftward as indicated by the arrow in FIG. 4 (c) around the fixing pin 2e to open an arc. The blade 3 cuts into the side wall surface 4c of the prepared hole 4a of the workpiece 4, and the rotation of the blade 3 and the blade support 2 receives a resistance force.

By this resistance, the blade support 2 and the tool body 1
Is suppressed, and the blade driving body 2 and the tool main body 1 are integrally formed, and the rotational driving force applied to the tool main body 1 is transmitted to the blade supporting body 2. And the tool body 1
The rotational driving force of the blade 3 overcomes the resistance force of the blade 3 to bite into the side wall surface 4c of the prepared hole 4a of the workpiece 4 to suppress the rotation of the blade 3 and the blade support 2, so that the blade 3 is covered. The side wall surface 4c of the prepared hole 4a of the workpiece 4 is cut, and the tool body 1 is cut as described above.
Slides in a spiral motion with respect to the blade support 2, and the pair of blades 3 is further opened.

During this series of operations, the side wall of the prepared hole 4a of the workpiece 4 is cut into an arc shape by a pair of blades 3 as shown in FIG. When the amount of protrusion from the tool 1 is minimized, the guide pin 2g is located at the rear end portions 1a2, 1b2 of the spiral slits 1a, 1b, and the pair of blades 3 open perpendicular to the tool body 1. At the same time, the straight portions 3b of the pair of blades 3 reach the bottom surface 4b of the prepared hole 4a, and the bottom portion of the prepared hole 4a has a dome shape (hemispherical shape).
Is formed (see FIG. 4C).

As described above, the guide pins 2g provided on the blade support 2 engage with the double helical slits 1a and 1b formed on the tool main body 1, and the tool main body 1 By making a helical motion and slidable, the resistance force applied to the blade 3 during the cutting of the widened hole 5 can be smoothly released, so that the blade 3 can be opened smoothly. I have.

That is, the resistance force applied to the blade 3 during the cutting of the enlarged bottom hole 5 is controlled by the guide pins 2g and the spiral slits 1a and 1b.
However, since the tool body 1 is rotating while being pushed in, the guide pin 2g is helically slit 1a, 1
b, the front end 1a of the spiral slits 1a, 1b
This moves from 1, 1b1 toward the rear end portions 1a2, 1b2, so that the above-mentioned resistance can be released.

In particular, since the slit engaged with the guide pin 2g is formed in a spiral shape, the resistance force applied to the blade 3 during cutting can be reduced by the slit of the tool body 1 through the guide pin 2g of the blade support 2. The blade 3 can be opened smoothly.

After forming the dome-shaped enlarged hole 5, the rotation of a rotating means (not shown) such as an electric drill is stopped, and the tool body 1 is pulled out from the enlarged hole. The curved portion 3a of the pair of blades 3 abuts and slides on the curved surface portion 4d on the inlet side of the workpiece 4 so that the pair of blades 3 move in the longitudinal direction of the blade support 2 on the side opposite to the tool body 1 (tip side). And can be pulled out from the workpiece 4 in which the enlarged bottom hole 5 is formed (see FIG. 4D).

Here, from the state of FIG. 4C, the tool main body 1 is further pushed into the workpiece 4 in the advancing direction (from right to left in FIG. 4C). The depth of the dome-shaped bottom-opening hole 5 is further extended by the straight portions 3b of the pair of blades 3 opened orthogonally to the blade 3 to extend the bell-shaped bottom-opening hole 7.
Can be formed (see FIG. 5).

In the above embodiment, the helical slits 1a and 1b formed on the side surface of the tool body 1 are shown in FIG.
From the right to the left (the boring tool A is inserted into the prepared hole 4a of the workpiece 4).
In the description above, the case is described in which a spiral curve is drawn in a clockwise direction toward the right direction.
A double spiral slit is formed on the side of the tool body 1 as shown in FIG.
4B, the tool main body 1 formed by drawing a counterclockwise spiral curve from the right to the left and held by a chuck of an electric drill (not shown) is moved leftward from the right to the left in FIG. By rotating the tool body 1 and the blade support 2 counterclockwise in the traveling direction (from right to left in FIG. 4B), the tool body 1 and the blade support 2 are rotated in the counterclockwise direction, and the bottom-opening holes 5, 7 are formed in substantially the same manner as described above. May be formed.

Further, in the above-described embodiment, an example in which the entire tool body is formed in a cylindrical shape has been described. However, as another configuration, one end of the tool body is formed in a column shape, and the grip portion of the rotating means is formed. And the other end of the tool main body to at least the intermediate portion may be formed in a tubular shape, and the tubular portion may be provided with the above-described double spiral slit.

[0048]

According to the present invention, a pre-hole having a predetermined depth is formed in a work material in advance, and the bottom-extending hole is formed by using the boring tool having the above-described structure. The depth of the bottom hole can be changed freely, and furthermore, the bottom hole can be formed in the shape of a dome or a bell, so that the space volume of the bottom hole can be made relatively large, and the expansion anchor or chemical can be injected to inject chemicals. Sufficient space can be secured when fixing the.

Also, since the components constituting the boring tool are relatively simple, the manufacturing cost of the boring tool can be reduced.

In addition, since the method of forming the bottom hole using the boring tool is relatively simple, the labor for forming the bottom hole can be reduced.

Further, the work piece is formed by engaging a guide pin provided on a blade support for supporting a pair of blades with a double helical slit provided in the tool body and performing a spiral movement. It is possible to smoothly release the resistance force applied to the blade when cutting the blade, and to smoothly open and close the pair of blades.

[Brief description of the drawings]

FIG. 1 is an explanatory side sectional view showing a configuration of a boring tool according to the present invention.

FIG. 2A is a side sectional explanatory view showing a configuration of a cylindrical tool body, FIG. 2B is a left sectional view of the tool body, and FIG.
FIG. 4 is a diagram illustrating a configuration of a double spiral slit provided on a side surface of a tool main body.

FIG. 3A is a plan view showing a configuration of a blade support, and FIG.
FIG. 3 is a front view showing a configuration of a blade support, FIG. 4C is a front view showing a shape of a pair of blades, and FIG. 4D is a side view showing a configuration of a guide pin.

4A is a diagram showing a state in which a prepared hole is formed in a workpiece, FIG. 4B is a diagram showing a state in which a boring tool according to the present invention is inserted into the prepared hole, and FIG. It is a figure which shows a mode that the dome-shaped enlarged hole is formed by the boring tool which concerns on this invention, and (d) is a figure which shows a mode that the boring tool which concerns on this invention is pulled out from an extended hole.

FIG. 5 is a view showing a state in which the depth of the bottom-hole is extended to form a bell-shaped bottom-hole.

FIG. 6 is a diagram showing a conventional example.

[Explanation of symbols]

 A: Boring tool 1: Tool body 1a, 1b: Spiral slit 1a1, 1b1: Front end 1a2, 1b2: Rear end 1c: Grip 1d: Front 2: Blade support 2a: Blade receiving slit 2b ... Slope surface 2c ... Blade support 2d ... Hole 2e ... Fixing pin 2f ... Hole 2g ... Guide pin 2h ... Tip 3 ... Blade 3a ... Curve portion 3b ... Linear portion 3c ... Hole 3d ... Tip 4 ... Work material 4a … Prepared hole 4b… bottom surface 4c… side wall surface 4d… entrance side curved surface part 5… bottom-opening hole 6… drill tooth 7… bottom-opening hole

Claims (2)

[Claims] A tool body having a grip portion of a rotating means at one end, a cylindrical shape from the other end to at least an intermediate portion, and a double helical slit provided in the cylindrical portion; A blade support fitted and slidably fitted with the tip protruding, and a pair of blades coaxially supported by the tip of the blade support; A boring tool comprising a pair of guide pins projecting diagonally from a side surface of a support body, the guide pins being guided by a slit of the tool body. 2. Drilling a pilot hole in a workpiece to be boring;
Insert the boring tool according to claim 1 into the pilot hole in a state where the tips of the pair of blades are folded back toward the tool body,
A method of forming a bottomed hole, wherein the tool body is rotated by rotating means, and the blade is expanded to form a bottomed hole in the workpiece.