JPH0444590A - Drilling device for undercutting innermost recess in fitting hole for widening anchor - Google Patents

Abstract

PURPOSE:To enable an undercut section to be drilled exactly and easily at the specified position of the innermost recess of a fitting hole by push-moving a drilling device main-body to project a cutting edge device fitted at a bearing rod front-end, in the radial direction, and by rotating the main body in this posture. CONSTITUTION:The shaft section 2 of a drilling device main-body 1 provided with a socket section 4 at a large diameter section 5 at a tip is connected to a motor rotary-tool 30, and a guide shaft 9 is inserted into a fitting hole 32 set on a concrete structural-body 31, and a bearing seat 8 is positioned. After that, when,the main body 1 resisting a first spring means 27 is push-moved to the side of the bearing seat 8, then a bearing rod 21 is projected resisting a second spring means 26, and a cutting edge device 23 fitted at its front end is projected in the radial direction from the front end opening 12a of a cutting edge device fitting hole 12. When the main body 1 is rotated by the motor rotary-tool 30 in this posture, then the wall surface of the fitting hole 32 is drilled to be widened with the cutting edge device 23, and a circular-truncated- cone-shaped undercut section 34 is formed to be drilled.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a cutting device that undercuts the inner depth of a mounting hole in advance when planting an expansion anchor in a concrete structure (wall, ceiling, floor, etc.). .

BACKGROUND ART Conventionally, when installing an expansion anchor in a mounting hole provided in a concrete structure, in order to facilitate expansion of the anchor and obtain high pull-out strength (holding force), It is known to undercut the inner depth of the cone in the shape of a truncated cone (see, for example, Japanese Patent Laid-Open No. 1-150008).

Problem to be Solved by the Invention However, unless such an undercut is precisely provided at a predetermined position deep inside the mounting hole, the intended purpose cannot be fully achieved. All of the cutting equipment used to make the cuts had the problem of being imperfect and having low work efficiency.

The present invention has been made in view of the above circumstances, and provides a cutting device for undercutting the innermost part of the mounting hole of an expansion anchor, which enables the undercutting of the mounting hole to be performed accurately, extremely easily, and efficiently. is intended to provide.

Means for Solving the Problems In order to achieve the above object, the cutting device of the present invention has a shaft portion connected to an electric rotating tool at one end, and a socket portion provided at the large diameter portion of the other end. A guide shaft of a predetermined length is provided at the front end of a main body and a base that is slidably inserted in the socket portion of the main body only in the axial direction through a catch, and the guide shaft is inclined with respect to the axis and is provided at the rear of the base. The tool mount includes a tool mount having a cutter mounting hole extending from the end to the front end of the guide shaft, and a support rod having a cutter attached to the front end, and the tool mount includes a first spring means built into the main body. is urged forward by
On the other hand, the support rod is slidably inserted into the cutter mounting hole so that its rear end protrudes from the base, and the cutter is moved into the mounting hole by a second spring means fitted into the cutter mounting hole. The guide shaft is inserted into a mounting hole provided in a concrete frame, and the main body is pushed into the first spring means with the seat in contact with the entrance end surface of the mounting hole. When the support rod is pushed against the second spring means, the cutter is moved radially from the front end opening of the cutter attachment hole. It was designed to stand out.

In order to smoothly rotate the tool mounting body during the cutting operation, it is preferable to assemble a thrust bearing to the seat.

Effect With the above configuration, when the shaft portion of the main body is connected to an electric rotating tool and the guide shaft is inserted into a mounting hole provided in a concrete frame, the seat is positioned by coming into contact with the end surface of the mounting hole. Next, when the main body is pushed toward the receiving seat against the first spring means, the support rod is protruded against the second spring means, and the support rod is attached to the front end of the support rod. The cutter protrudes radially from a front end opening of the cutter attachment hole. When the main body is rotated with an electric rotary tool in this posture, the cutting tool, which rotates in conjunction with this, cuts and widens the wall surface of the mounting hole, thereby cutting a truncated conical undercut portion.

Example Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a cutting device according to the invention.

Reference numeral 1 denotes a main body, which has a shaft portion 2 at one end that is connected to an electric rotary tool, and a socket portion 4 having a hexagonal cross section in a large diameter portion 3 at the other end. The bottom surface 4a of the socket portion 4 is provided with a narrow hole 5 extending along the axis.

Reference numeral 6 denotes a tool mounting body, which has a base 7 formed in a hexagonal column shape that is slidably inserted into the socket portion 4 of the main body 1 only in the axial direction, and a guide shaft is attached to the front end of the base 7 via a seat 8. 9 is provided protrudingly, and a shaft 10 to be inserted into the hole 5 is provided protrudingly from the rear end, and a notch 11 extending in the axial direction is provided on the side surface of the intermediate portion of the shaft 10.
is provided. The guide shaft 9 has an outer diameter slightly smaller than the diameter of a mounting hole 32 provided in a concrete frame 31, which will be described later, as shown in FIG. There is.

Further, the tool mounting body 6 is provided with a cutting tool mounting hole 12 that is inclined with respect to the axis and extends from the rear end of the base 7 to the front end of the guide shaft 9 . Front end opening 1 of the blade attachment tag 12
2a, as best shown in FIGS. 2 and 3,
It extends from the front end surface of the guide shaft 9 to the side surface. The inside of the cutter attachment hole 12 is a three-stage hole with different diameters and cross-sectional shapes, and the front end portion is formed as the through hole 13 with the smallest diameter.
The middle part has a larger diameter than the through hole 13 and has a spring seat 14 formed therein, and the rear end part has a non-circular hole 15 having a hexagonal cross section. The non-circular hole 15 is provided for positioning a cutting tool support rod 21, which will be described later, and holding it in a rotation-prevented state.

Furthermore, a thrust bearing 16 is assembled to the seat 8 of the base 7. As shown in FIG. 2, the thrust bearing 16 has a large number of needle rollers 18 arranged radially in a retainer 17, interposed between a catch seat 8 and a raceway ring 19, and the whole is covered with a bearing cover 20. The cover has a structure in which one edge 20a of the cover is bent and held in place by the catch seat 8, and is provided to reduce rotational resistance of the tool mount 6 during cutting operations, which will be described later. .

21 is the support rod of the cutting tool, and the bariman 22 (
A plate-shaped cutter 23 made of a carbide tip is fitted into the cutter 23 (see FIG. 3), and a rake angle (α) is provided on the lower surface 23a of the cutter 23, the side edge 23b of which serves as a cutting edge. On the other hand, the rear end portion of the support rod 21 is provided with a hexagonal shaft portion 24 and a shaft portion 25 that are fitted into the non-circular hole 15 of the cutting tool attachment hole 12.

As shown in FIG. 2, the support rod 21 is positioned by fitting the hexagonal shaft portion 24 into the non-circular hole 15 so that it is prevented from rotating, and also has a push spring (coil spring) 26 fitted into the mounting hole 12. , the shaft #25 protrudes outward from the base 7,
In addition, the cutting tool 23 is urged to retract into the through hole 13.

As shown in FIG. 1, the tool mounting body 6 incorporating the cutter support rod 21 as described above has the base 7 slidably inserted into the socket portion 4 of the main body 1 only in the axial direction, and the shaft 10 is inserted into the hole 5 and is assembled to the main body 1 while being biased forward (in the direction away from the main body 1) by the push spring (coil spring) 27 fitted in the hole 5, and A set screw 28 screwed onto the main body 1 is engaged with the notch 11 and can be slid in the axial direction within the range of the notch 11 with respect to the main body 1.

The abrasive device having the above configuration is used as shown in FIG.

First, the shaft portion 2 of the main body 1 is connected to the electric rotary tool 30, and the guide shaft 9 is inserted into the mounting hole 32 drilled in advance in the concrete frame 31. Then, the seat 8 of the inserted guide shaft 9 is supported in contact with the inlet end surface 33 of the mounting hole 32 via the thrust bearing 16, and the front end of the guide shaft 9 is placed in the deep part of the mounting hole 32 at a place to be undercut. accurately positioned.

Next, the main body 1 is pressed by the spring 27 via the electric rotary tool 30.
When pushed toward the catch seat 8 side against the
is pressed by the socket bottom surface 4a, and in conjunction with this, the support rod 21 is pushed out against the push spring 26, and the cutting tool 2 at the front end is pressed.
3 protrudes from the front end opening 20a of the mounting hole 12 in the radial and axial directions. When the main body l is rotated by the electric rotary tool 30 with the cutting tool 23 protruding in this way,
The guide shaft 9 is rotated via the base 7, and the cutting tool 23 rotating around the axis of the guide shaft 9 cuts and widens the wall surface 32a of the mounting hole 32, thereby forming an undercut portion 34 in the shape of a truncated cone.
Delete. At this time, since the thrust bearing 16 is interposed between the catch seat 8 and the inlet end face 33, the rotation of the guide shaft 9 is performed smoothly.

Since the amount of protrusion of the cutter 23 is proportional to the pushing distance of the main body 1,
At the beginning of the machining process, the amount of protrusion of the cutting tool 23 is kept small as shown in Fig. 5, and if the amount of protrusion is gradually increased, the cutting resistance is very small and accurate undercutting can be easily and quickly achieved. The cut portion 34 can be machined.

Effects of the Invention Since the present invention is configured as described above, it is possible to form an accurate undercut portion at a predetermined position deep inside a mounting hole provided in a concrete frame very easily and efficiently.

Additionally, since the device of the present invention can be installed by simply applying rotational force to the main body using an electric rotating tool, it is extremely quiet compared to conventional devices that require applying axial impact force and rotational force using an electric hammer drill, etc. work can be done. This is particularly advantageous when installing on existing buildings.

[Brief explanation of the drawing]

FIG. 1 is a partially vertical front view of the cutting device according to the present invention, and FIG.
The figure is an enlarged longitudinal cross-sectional view of the main part, Fig. 3 is a view taken along line 3-3 in Fig. 2, Fig. 4 is a partially longitudinal front view showing an example of the same use, and Figs. 5 and 6. The figure is an explanatory view showing the cutting process state. 1... Main body 2... Shaft part 3... Large diameter part 4... Socket part 6... Tool mounting body
7... Base 8... Seat 9... Guide shaft 12... Cutting tool mounting hole 12a... Front end opening 16
... Thrust bearing 21 ... Support rod 23 ... Cutting tool 26.27 ... Push spring 30 ... Electric rotating tool 31 ... Concrete frame 32 ... Mounting hole 34 ... Undercut part Figure 11 U O-・Ll at the end of the 11th month 5z・Ruda 1 to 2...Shaft part 4° ゛Noke・/ )-1-P 7・L Iku...$n Tsumugi 1za-f + Naojuku Kakuguchi zl・・・Emurai zl,,z'L n L+1'h Jf・Tato to Sifrit, 34゛ A〉Fnyfy-tlJj Figure j

Claims (3)

[Claims] (1) A main body having a shaft portion connected to an electric rotary tool at one end and a socket portion provided in a large diameter portion at the other end, and a base portion that is slidably inserted into the socket portion of the main body only in the axial direction. A tool having a guide shaft of a predetermined length protruding from the front end of the tool through a catch, and a cutting tool mounting hole that is inclined with respect to the axis and extends from the rear end of the base to the front end of the guide shaft. a mounting body; and a support rod having a cutting tool attached to its front end; the tool mounting body is biased forward by a first spring means built into the main body, and the support rod is inserted into the cutting tool mounting hole. a rear end portion of which is slidably inserted into the base portion and protrudes from the base portion, and is biased so that the cutter is retracted into the attachment hole by a second spring means fitted into the cutter attachment hole; The guide shaft is inserted into a mounting hole provided in a concrete frame, and the main body is pushed toward the seat against the first spring means with the seat in contact with the entrance end face of the mounting hole. When the anchor is moved, the support rod is pushed against the second spring means so that the cutting tool protrudes in the radial direction from the front end opening of the cutting tool mounting hole. A cutting device that undercuts the deep inside of the mounting hole. (2) A cutting device for undercutting a deep inside of an attachment hole of an expansion anchor according to claim 1, wherein a thrust bearing is assembled to the seat. (3) A cutting device for undercutting a deep inside of an attachment hole of an expansion anchor according to claim 1 or 2, wherein the cross-sectional shape of the socket portion of the main body and the base of the tool attachment body is hexagonal.