JPH04294912A - Cutting-forming device to undercut innermost installation hole of extensively opening anchor - Google Patents

Abstract

PURPOSE:To undercut efficiently the innermost installation hole of an extensively opening anchor arranged in a concrete body in a truncated cone shape. CONSTITUTION:A cutter holder 6 is inserted/embedded into a socket part 3 of a device body 1 provided with a shaft part 4 connected to an electrically operated rotary machine tool so as to be movable in sliding only in the shaft direction, and is energized so as to be extruded freely by means of a spring 9. The cutter holder 6 has a guide shaft 11 projecting from a receiver seat (flange part) 10 arranged in its front part, and passes through from the rear edge of the cutter holder 6 to the front edge of the guide shaft 11, and has also a cutter installation hole 12 inclined against the shaft line. A cutter 22 is installed in the front edge part of a support bar 21 inserted into the cutter installation hole 12 so as to be movable in sliding freely. The rear edge of the support bar 21 is connected to the device body 1 through a connecting arm 24. When the device body 1 is push-moved to the flange 10 side against the spring 9, by being interlocked with this, the support bar 21 is extruded from the cutter installation hole 12, and the cutter 22 is projected from the front edge opening of the guide shaft 11 in the radial direction and in the shaft direction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting device that undercuts the inner depth of a mounting hole before fixing an expansion anchor to a concrete structure (wall, ceiling, floor, etc.).

0002

[Prior Art] Conventionally, when fixing an expansion anchor to 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 a hole into a truncated conical shape (for example, Japanese Patent Laid-Open No. 1-1
(See Publication No. 50008).

0003

[Problem to be Solved by the Invention] However, unless such an undercut is accurately provided at a predetermined position deep inside the mounting hole, the intended purpose cannot be fully achieved. All of the cutting equipment used to create this undercut has the problem of being incomplete and having low working efficiency.

The present invention has been made in view of the above-mentioned circumstances, and the present invention has been made by undercutting the inner depth of the mounting hole of an expansion anchor, which allows the undercutting of the mounting hole to be performed accurately, extremely easily, and efficiently. The purpose of the present invention is to provide an abrasion device that

[0005]

[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 rotary tool on the rear side of the bottom of the bottomed cylindrical body forming the socket portion. a cutter holder which is fitted into the socket so as to be slidable only in the axial direction and which is biased so as to be pushed out by a spring means built into the socket; It protrudes from the provided catch,
and a guide shaft provided coaxially with the cutter holder, a cutter mounting hole that penetrates from the rear end of the cutter holder to the front end of the guide shaft and is inclined with respect to the axis of the cutter holder, and the cutter mounting hole. a support rod that is slidably inserted into the support rod and has a cutter attached to its front end, and a connecting arm that has one end pivotally connected to the rear end of the support rod and the other end pivotally connected to the device main body. The guide shaft is inserted into a mounting hole provided in a concrete frame, and the apparatus main body is pushed against the spring means toward the seat with the seat in contact with the entrance end face of the mounting hole. When the cutter attachment hole is pushed, the support rod is pushed out along the cutter attachment hole via the connection arm, and the cutter protrudes radially from the front end opening of the cutter attachment hole. ing.

[0006] In order to smoothly rotate the cutter holder during the cutting operation, it is preferable to assemble a thrust bearing to the seat.

[0007]

[Operation] With the above configuration, when the shaft portion of the device main body is connected to the electric rotating tool and the guide shaft is inserted into the mounting hole provided in the concrete frame, the seat comes into contact with the end face of the mounting hole and is positioned. be done. Next, when the main body of the device is pushed toward the seat against the spring means, the support rod is pushed out along the cutter attachment hole via the connection arm, and the front end of the support rod is pushed out along the cutter attachment hole through the connection arm. The cutter attached to the cutter protrudes radially from the front end opening of the cutter attachment hole. In this posture, when the device body is rotated by an electric rotary tool and pushed toward the concrete body, the cutter, which rotates in conjunction with this, cuts and widens the wall surface of the mounting hole, forming a truncated conical shape. Remove the undercut.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

FIG. 1 shows a longitudinal sectional front view of a cutting device according to the present invention, and FIG. 2 shows the same in use. The device main body 1 has a bottomed cylindrical body 2 forming a socket part 3 and a shaft part 4 connected to the bottom rear side of the bottomed cylindrical body 2, and the shaft part 4 is connected to an electric rotary tool ( (see FIG. 2) to apply rotational force to the device main body 1. The socket portion 3 is formed into a hole having a hexagonal cross-sectional shape.

The cutter holder 6 is formed into a hexagonal column shape and is slidably inserted into the socket portion 3 only in the axial direction.
By engaging a locking pin 8 screwed onto the bottomed cylindrical body 2 of the cylindrical body 2, it is possible to slide in the axial direction within the range of the engagement groove 7. It is biased to push out. The engagement hole 7 and the stop pin 8 are provided at three locations on the outer periphery of the cutter holder 6 with a phase shift of 120 degrees, so that the cutter holder 6 can move smoothly in the axial direction with respect to the device body 1. It is set as. Further, a flange portion 10 serving as a seat is provided at the front end of the cutter holder 6, and a guide shaft 11 that protrudes from the flange portion 10 and is coaxial with the cutter holder 6 is formed integrally with the cutter holder 6. has been done. The guide shaft 11 has an outer diameter slightly smaller than the diameter of a mounting hole 32 (see FIG. 2) provided in a concrete frame 31 (described later), and its length is set in accordance with the undercut position deep inside the mounting hole 32. ing.

The cutter holder 6 is also provided with a cutter mounting hole 12 that is inclined with respect to the axis and extends from the rear end to the front end of the guide shaft 11 . The cutter mounting hole 12 is formed into a square hole 12a with a square cross section on the side of the holder 6 in the latter half in order to hold the cutter support rod 21, which will be described later, in a non-rotating state. On the side, there is a circular hole 12b with a smaller diameter than the square hole 12a.
The front end opening 12c is formed in the guide shaft 1.
It extends from the front end surface of 1 to the side surface.

A thrust bearing 13 is assembled to the flange portion 10 which is a seat of the cutter holder 6. The thrust bearing 13 is interposed between a bearing case 14 rotatably fitted into the base end of the guide shaft 11, a retainer 15 fixed to the inner bottom of the bearing case 14, and the retainer 15 and the flange 10. The bearing case 14 is connected to the flange portion 10 via a snap ring 17.
The cutter holder 6 has a structure in which the cutter holder 6 is locked and held, and is provided in order to reduce the rotational resistance of the cutter holder 6 during cutting operations, which will be described later. In addition, as shown in the figure, the bearing case 14
By providing a guide sleeve 18 that fits over the base end of the guide shaft 11, it is possible not only to effectively prevent the guide shaft 11 from being worn out during rotation in use, but also to prevent the thrust bearing 13 from being worn out.
can be rotated smoothly.

A plate-shaped cutter 22 made of a carbide tip is attached to the front end of the cutter support rod 21.
The lower edge 22a and side edge 23b of the cutter 22 function as cutting edges. On the other hand, a square shaft portion 23 that fits into the square hole 12a of the cutter mounting hole 12 is integrally provided at the rear end portion of the support rod 21. The support rod 21 is positioned such that the square shaft portion 23 is inserted into the square hole 12b and is prevented from rotating, and the cutter 22 at the front end is placed in the cutter holder 6 so that it can protrude from the front end opening 12c of the circular hole 12b. Can be assembled. On the other hand, one end of a connecting arm 24 is pivotally connected to the rear end of the square shaft portion 23 of the support rod 21 via a pin 25. The other end of the connecting arm 24 is located in a through hole 26 provided at the bottom of the bottomed cylindrical body 2, and is pivotally connected to the bottomed cylindrical body 2 via a pin 27. That is, the support rod 21 is connected to the bottomed cylindrical body 2 via the connecting arm 24, and as shown in FIG.
It is designed not to protrude from 2c.

The cutting apparatus having the above structure is used as shown in FIG.

First, the shaft portion 4 of the device body 1 is connected to the electric rotary tool 30, the guide shaft 11 is inserted into the mounting hole 32 drilled in advance in the concrete frame 31, and the bearing case 14 of the thrust bearing 13 is installed. By abutting and supporting the inlet end surface 33 of the hole 32, the front end of the guide shaft 11 is attached to the mounting hole 3.
2. Accurately position the area where the undercut is to be made.

Next, the electric rotary tool 30 is used to rotate the device body 1.
thrust bearing 1 against spring 9 while rotating
When the support rod 21 is pushed toward the third side, the support rod 21 is pushed out via the connecting arm 24, and the cutter 22 at the front end projects from the front end opening 20c of the mounting hole 12 in the radial and axial directions. When the cutter 22 is pushed toward the concrete frame 31 while rotating the apparatus main body 1 with the electric rotary tool 30 in the protruding state, the guide shaft 11 is rotated via the cutter holder 6, and the guide shaft 11 is rotated through the cutter holder 6. Axis 11
The cutter 22 rotates around the axis of the mounting hole 32.
The wall surface 32a is cut and expanded to form a truncated conical undercut portion 34. At this time, since the thrust bearing 13 is interposed between the cutter holder 6 and the inlet end face 33, the guide shaft 11 rotates smoothly.

Since the protrusion length of the cutter 22 is proportional to the pushing distance of the device main body 1, the protrusion amount of the cutter 22 is kept small at the beginning of the machining process, and the protrusion amount is gradually increased. The cutting resistance is very small, and the undercut portion 34 can be cut easily and quickly with precision.

After the predetermined undercut portion 34 is machined, when the pressing action of the device main body 1 is released, the cutter holder 6 is pushed back by the spring 9, and the support rod 21 is relatively connected to the device main body via the connecting arm 24. It will be pulled back to the 1st side. As a result, the cutter 22 retreats inward from the front end opening 22C, and the guide shaft 11 is pulled out from the mounting hole 32, completing the construction.

[0019]

As the present invention is constructed 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.

Furthermore, the device of the present invention can be installed by simply applying rotational force to the device body using an electric rotary tool, compared to conventional devices that require applying axial impact force and rotational force using an electric hammer drill or the like. This allows for extremely quiet cutting work. This is particularly advantageous when installing on existing buildings.

[Brief explanation of drawings]

FIG. 1 is a partially vertical front view of a cutting device according to the present invention.

FIG. 2 is a partially longitudinal front view showing the state of use.

[Explanation of symbols]

1　Device body 2 Bottomed cylindrical body 3 Socket part 4 Shaft part 6 Cutter holder 9 Spring 10 Flange part (catcher) 11 Guide shaft 12 Cutter mounting hole 12c Front end opening 13 Thrust bearing 21 Support rod 22 Cutter 24 Connecting arm 30 Electric rotary tools 31 Concrete frame 32 Mounting hole 34 Undercut part

Claims (3)

[Claims] 1. A device main body, which is provided with a shaft portion connected to an electric rotating tool on the rear side of the bottom of a bottomed cylindrical body forming a socket portion, and a device body that is fitted into the socket portion so as to be slidable only in the axial direction and a cutter holder that is biased to push out by a spring means built into the socket portion, and a guide shaft that protrudes from a catch provided at the front of the cutter holder and is coaxial with the cutter holder. , a cutter mounting hole that penetrates from the rear end of the cutter holder to the front end of the guide shaft and is inclined with respect to the axis of the cutter holder; and a cutter mounting hole that is slidably inserted into the cutter mounting hole;
and a support rod having a cutter attached to its front end, and a connecting arm having one end pivotally connected to the rear end of the support rod and the other end pivotally connected to the device main body, When inserted into a mounting hole provided in a concrete frame and pushing the device main body toward the seat against the spring means with the seat in contact with the entrance end face of the mounting hole, the device is interlocked with this. and the support rod is pushed out along the cutter attachment hole through the connecting arm, and the cutter is configured to protrude radially from a front end opening of the cutter attachment hole. A cutting device that undercuts the back. 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. The 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 cutter holder is hexagonal.