JPH09234729A - Undercut drill apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an undercut drill apparatus not obstructed in drilling work by a cut powder and adapted to a small diameter hole. SOLUTION: In an undercut drill apparatus having a drill shaft 20 and a drill blade member 40 and relatively moving both of them under rotation to form an expanded diameter part to a preliminarily bored concrete hole by the blade part 43 provided to the leading end of the drill blade member 40, a shaving part 25 is formed to the drill shaft 20 along the axis thereof and the cross section of the drill blade member is formed into a shape wherein a columnar member is cut along the axis thereof to join the blade member to the shaving part 25. The blade part 43 of the drill blade member 40 is fitted in the guide groove 27 formed to the head part 24 provided to the leading end part of the drill shaft 20 and provided with a bottom part having an inclined surface inclined toward the outer peripheral surface of the leading end of the head part and the drill shaft 20 and the drill blade member 40 are relatively moved to form an expanded diameter part expanded by the protruding quantity of the blade part 43 from the head part 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undercut drill device for forming an enlarged diameter portion having a diameter larger than the diameter of an already drilled hole, and more particularly to a drill device adapted for a small diameter hole.

[0002]

2. Description of the Related Art A hole for fixing a metal expansion anchor to concrete is generally formed to have a diameter substantially the same as that of the anchor. However, a diameter expansion portion having a diameter larger than the diameter of the hole formed is formed. It is known that when the anchor is fixed afterwards, the pull-out strength of the anchor increases, and therefore various undercut drills have been developed and put to practical use.

FIG. 5 shows an undercut drill according to the prior art. A is a device disclosed in Japanese Utility Model Laid-Open No. 61-50410, and B is a device disclosed in Japanese Utility Model Publication No. 4-14166. Is.

In the invention A, the tip of the wedge center 4 is formed on the overhanging jaw 5, and the cutting edge 8 is formed on the outer peripheral portion of the wedge center 4.
A pair of main bodies 7 each having a slidable body are slidable, and the shank 2 integrally provided with the wedge center 4 is connected to a rotary tool to rotate the entire drill to stretch the main body 7 when forming the expanded diameter portion. It is pushed out toward the protruding jaw 5. Cutting edge 8
When moving along the guide groove 9 of the overhanging jaw 5, the overhanging jaw 5
And an enlarged diameter portion is formed on the wall of the hole.

According to this invention, since the body 7 having the cutting blade is provided in a pair, there is an advantage that the work efficiency of the undercut is good, but the diameter of the drill itself cannot be made smaller than about 15 mm. Therefore, there is a problem that it cannot be applied to the undercut of small holes. This is because, since the body is composed of a pair, if the body is made thin to reduce the diameter of the drill, the concrete wall cannot be cut and the body itself breaks.

The device B is also an improved version of the device A, in which the elastic rod 1 provided with the cutting blade 3 is housed as a single unit in the hollow portion 5 of the body 4 and the tip of the body 4 is provided. An opening 6 is provided on the side wall of the part, and the inclined surface 5a is formed toward the opening 6. When the elastic rod 1 moves in the hollow portion 5 and reaches the inclined surface 5a, the cutting blade 3 projects outward from the outer peripheral surface of the main body 1 through the opening 6 and undercuts the wall surface of the hole.

In this invention, the single elastic rod 1 is used so that it can be fitted into a small diameter hole.
Has a diameter substantially the same as the hole diameter, and the elastic rod 1 having the cutting edge 3 slides in the hollow portion 5 without a gap. On the other hand, the cutting work inside the hole has no escape area for the cutting chips. Therefore, when concrete cutting chips are clogged between the elastic rod 1 and the hollow portion 5, the sliding operation of both is hindered and the cutting work cannot be performed. There are still problems such as being expected.

[0008]

DISCLOSURE OF THE INVENTION The present invention is designed so that a single blade body can be used to expand the diameter, and the cutting work is not hindered by the cutting chips, and the undercut is adapted to a small diameter hole. A cut drill device is provided.

[0009]

Means for solving the problem in the present invention is to have a drill shaft 20 and a drill blade 40, which are provided at the tip of the drill blade 40 by rotating and relatively moving them. A device for forming a diameter-expanded portion in a concrete hole that has been pre-drilled by the blade portion 43, in which the drill shaft 20 has a shaving portion 25 formed along the shaft,
The drill blade 40 is joined to the cutting portion 25 in a cross-sectional shape of a cylindrical body cut along the axis, is formed on the head 24 provided at the tip of the drill shaft 20, and the bottom is the outer peripheral surface of the tip of the head. The blade portion 43 of the drill blade body 40 is fitted into the guide groove 27 having an inclined surface inclined toward the
It is characterized in that a relative movement mechanism for relatively moving 0 and the drill blade 40 is provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 20 designates a drill shaft, and a connecting shaft 2 is provided on one side with a flange 21 as a boundary.
2, a guide shaft 23 is integrally formed on the other side, and the guide shaft 23 has a small diameter portion 23a formed in the middle thereof and a head portion 24 having a diameter larger than that of the small diameter portion 23a at the tip end portion. . Further, the guide shaft 23 includes the connecting shaft 22 to the head 24.
The shaving part 25 is formed to have a length reaching to and parallel to the axial direction. The scraping portion 25 forms an inclined surface 25a that is inclined toward the outer peripheral surface of the distal end portion of the head portion 24, whereby a guide side wall 26 having a triangular side surface is formed on the head portion 24. A guide groove 27 is formed in an inner portion sandwiched by the guide side walls 26.

In addition to the above, the drill shaft 20 is provided with a first elongated hole 28 that penetrates the flange 21 in the front-back direction of the flange 21 in a direction transverse to the shaft and extends in the axial direction, and the shaft is provided near the tip of the connecting shaft 23. A first pin hole 29 extending in the transverse direction is provided.

Reference numeral 30 denotes a drill main body, which is integrally formed with a shank 32 on one side with a flange 31 as a boundary, and on the other side with a cylinder 33 having a hole 34 reaching from the tip portion to the flange 31. , The hole 34 is the drill shaft 20.
It is for inserting the connecting shaft 22 and the flange 21. Therefore, the hole 34 is formed as a stepped hole having a large diameter 34a on the opening side. Further, the cylindrical body 33 is provided with a second pin hole 35 formed in a large diameter portion 34a near the opening, and penetrates a portion close to the flange 31 in a direction crossing the axis and along the axial direction. A second elongated hole 36 that extends is provided. A ring groove 37 is formed on the circumferential surface of the cylindrical body 33 where the second pin hole 35 is provided.

Reference numeral 40 denotes a drill blade, the cross section of which has a shape obtained by cutting a cylindrical body along the axis, and a trunk portion 41.
The connecting portion 42 having an arcuate portion larger than the trunk portion 41 is integrally formed on one side, and the leg portion 41a having an arcuate portion smaller than the trunk portion 41 is integrally formed on the other side. The drill blade body 40 is assembled by being joined to the scraping portion 25 of the drill shaft 20 described above, and has a circular cross-sectional shape when both are joined. Reference numeral 43 denotes a blade portion provided at the tip of the leg portion 41a, to which a cutting blade 44 is attached. Reference numeral 45 is a third pin hole provided in the connecting portion 42.

Reference numeral 50 denotes a cover cylinder, which is fitted to the cylinder 33 of the drill body 40 described above. A stepped spring seat 51 for mounting a coil spring, which will be described later, is formed on the inner side surface of the cover tubular body 50. Further, a fourth pin hole 52 is provided in the thick portion, and the fourth pin hole 52 is formed. A ring groove 53 is formed on the provided circumferential surface.

Reference numeral 60 denotes a first parallel pin, which is a drill blade 40.
And 61 for connecting the drill body 30 and the drill shaft 20, and 61 for connecting the cover cylinder 50, the drill body 30 and the drill shaft 20 to each other. 62 is a coil spring to be mounted in the cover tubular body 50;
3 is an O-ring fitted in the ring groove 37 of the drill body 30, and 64 is an O-ring fitted in the ring groove 53 of the cover cylinder 50.
Shows the ring.

The procedure of assembly and operation will be described with reference to FIGS. First, the cover cylinder 50 is placed inside and the coil spring 6
2 is accommodated and fitted in the cylinder 33 of the drill body 30.
Next, with the drill blade 40 joined to the scraping portion 25 of the drill shaft 20, the connecting shaft 22 and the connecting portion 42 are connected to the cylindrical body 3 described above.
The first parallel pin 60 is inserted from the second pin hole 35 into the hole 34 of No. 3, and the pin is inserted into the third pin hole 45 and the first pin.
The two are joined by passing through the long hole 28.

The drill blade 40 is slidable in the axial direction with respect to the drill shaft 20, but the drill blade 40 is at the most retracted position, that is, the drill blade 40 is in the direction of the shank 32 of the drill body 30. At the end of the moving direction, the blade portion 43
It is desirable that the tip end of is inserted into and engaged with the guide groove 27. An O-ring 63 is fitted in the ring groove 37 of the cylindrical body 33 so that the first parallel pin 60 does not fall off.

Next, the fourth pin hole 5 of the cover tubular body 50.
The second parallel pin 61 is inserted from 2 and the pin is passed through the second elongated hole 36 and the first pin hole 29 to connect the three members. Then, if the O-ring 64 is fitted into the ring groove 53 of the cover cylinder 50, the assembly of the drill device is completed.

In order to perform the drilling work using the drilling device thus assembled, the drilling device is inserted from the blade portion 43 into the hole 71 pre-drilled in the concrete skeleton 70, and the shank 32 is not shown. Attach the rotating tool and rotate (Fig. 4A). As a result, the drill device is rotationally driven. Further, in order to form the expanded diameter portion, the drill device is pushed toward the hole 71 of the concrete skeleton 70 (see FIG. 4).
B).

In FIG. 4A, when the drill body 30 is moved toward the tip of the drill, the second parallel pin 61 is fixed to the cover tubular body 50 and does not move, and the tubular body 33 is placed between the second elongated holes 36. Moves against the coil spring 62, and at the same time, the drill blade 40 moves along with the first parallel pin 60. At this time, the drill shaft 20 includes the drill body 30 and the drill blade body 4.
Although it moves relative to 0, as shown in FIG. 4B, substantially only the drill body 30 and the drill blade 40 move.

The blade portion 43 in the guide groove 27 provided in the head portion 24 of the drill shaft 20 has a blade portion 43 along the inclined surface 25a of the guide groove 27 as the drill blade 40 moves toward the tip of the drill. It projects outward from the center and cuts only the relevant part of the hole 71 already drilled. Since the blade portion 43 rotates together with the drill shaft in a state where the side surface portion is sandwiched between the guide side walls 26 of the guide groove 27, it is possible to perform work without so-called "backlash" during cutting, and stable drilling work is performed.

At the position where the drill body 30 is pushed in the most, the blade portion 43 projects from the head portion 24 in the maximum range, and the cutting blade 44 provided on the blade portion 43 forms the enlarged diameter portion 72 in the hole 71.

The part where the drill device is in contact with the hole 71 is the guide shaft 23 and the head 24 of the drill shaft 20 and the stem 41 of the drill blade 40, and the small diameter part 23a and the leg 41a are the holes 71. Since a gap is formed between the and, the drill work is not hindered by the chips generated during the diameter expansion work.

In addition to this, a drill blade body 40 having a blade portion 43
Since it is one, and the cross-sectional shape of both is joined to the drill shaft 20 to make it circular, it can be adapted to a small diameter hole.

[0025]

INDUSTRIAL APPLICABILITY The present invention has an effect that it can be applied to the work of expanding a small-diameter hole and that the cutting work is not hindered by cutting chips.

[Brief description of drawings]

FIG. 1 is a perspective view showing each component of a drill device.

FIG. 2 is a perspective view showing a state in which the whole is assembled and a part thereof is broken and before the work is started.

FIG. 3 is a perspective view showing the end of work in FIG.

FIG. 4 is a cross-sectional view showing a use state, where A is before starting work and B is at the end of work.

FIG. 5 is an explanatory view showing a conventional technique for both A and B.

[Explanation of symbols]

 20 drill shaft 21 flange 22 connection shaft 23 guide shaft 23a small diameter part 24 head 25 scraping part 25a inclined surface 26 guide side wall 27 guide groove 28 first long hole 29 first pin hole 30 drill blade 31 flange 32 shank 33 Cylindrical Body 34 Hole 35 First Pin Hole 36 Second Long Hole 37 Ring Groove 40 Drill Blade 41 Stem 41a Leg 42 Connecting Portion 43 Blade 44 Cutting Blade 45 Third Pin Hole 50 Cover Cylindrical 51 Spring Seat 52 Fourth pin hole 53 Ring groove 60 First parallel pin 61 Second parallel pin 62 Coil spring 63 O-ring 64 O-ring 70 Concrete skeleton 71 Hole 72 Expanded part

Claims (4)

[Claims] 1. A drill shaft (20) and a drill blade (40)
An apparatus for forming a diameter-expanded portion in a concrete hole previously drilled by a blade portion (43) provided at the tip of a drill blade body (40) by rotating the two and rotating them relative to each other. A cutting portion (25) is formed on the (20) along the axis, and a drill blade body (40) is joined to the cutting portion (25) in a cross section of a cylindrical body cut along the axis. Head (2 provided on the tip of the drill shaft (20)
The blade portion (43) of the drill blade body (40) is fitted into the guide groove (27) formed in 4) and having a bottom surface inclined toward the outer peripheral surface of the head end, and the drill is Axis (2
0) and a relative movement mechanism for relatively moving the drill blade (40). 2. A drill shaft (20) and a drill blade (40)
The undercut drill apparatus according to claim 1, wherein the two have a circular cross-sectional shape when they are joined. 3. The drill shaft (20) is a guide shaft (23).
And the head have the same diameter, and a small diameter part (23a)
The undercut drill device according to claim 1, wherein the undercut drill device is provided. 4. The drill blade (40) has a stem (41) and a blade (43) with the same radius of arc, and a leg (41a) with a small radius is provided in the middle of the two. The undercut drilling device according to claim 1 or 2, characterized in that.