JPH0118329Y2 - - Google Patents

Description

[Detailed description of the invention] This invention eliminates chips generated when cutting an enlarged hole with a diameter larger than the drill hole diameter, that is, an undercut, at a suitable location on the hole wall of a pre-drilled hole. The present invention relates to a diameter expanding hole cutting device that is retracted so as to prevent it from occurring.

When planting an anchor bolt in concrete that is to solidify, a blind end hole of a specified depth is drilled in the concrete, the base of the anchor bolt is inserted into this hole, and a slit is machined in the axial direction. Techniques such as enlarging the blind end cylindrical body and creating frictional resistance between it and the hole wall are adopted.

The pull-out strength of an anchor bolt planted in a concrete surface in this way is largely influenced by the bonding strength between the blind end cylinder and the hole wall. If you cut the hole wall into the hole to form an enlarged hole in advance,
The pull-out strength of anchor bolts can be significantly increased.

Therefore, the same applicant who created this invention inserted a wedge center into the main body so that it could rotate together with the main body on a common axis and be movable relative to the main body in the axial direction under the bias of a spring, and the wedge center was attached to the main body. The blade is moved along an overhanging jaw provided at the tip of the wedge center, and is configured to protrude outward from the overhanging jaw to cut the pre-drilled hole wall at an appropriate location to form an enlarged diameter hole. A device has been proposed.

For example, when using this device to cut an enlarged diameter hole at the bottom of a pre-drilled blind end hole, rotate the device with the lower end of the wedge center inserted into the hole in contact with the bottom of the hole, and press the main body against the spring. When the wedge is pressed into the hole, the cutting blade, which had been located inside the overhanging jaw at the base of the overhanging jaw of the wedge center, moves outward along the overhanging jaw due to the movement of the main body. It moves in an overhanging manner, cuts the hole wall, and eventually reaches the maximum overhang point of the overhanging jaw, protrudes outward from the overhanging jaw, and cuts an enlarged diameter hole in the hole wall. Later, when the pressing force of the main body is released, the cutting blade returns to its normal position at the base of the protruding jaw under the action of the spring in the reverse order of the movement described above, after which the device is withdrawn from the hole.

However, especially when drilling an enlarged hole at the bottom of a blind end hole using the diameter enlarged hole cutting device with the above configuration, the cutting operation position, that is, the cut generated by hole wall cutting at the hole bottom. Powder remains without being removed from the hole, which obstructs the movement of the cutting blade on the overhanging jaw.
In order to prevent the progress of cutting work and to pull out the device from the hole after work, the cutting blade must be returned to its normal position at the hole wall cutting position before the device can be pulled out. If chips remain and the cutting blade is buried in it, it will interfere with the return of the cutting blade on the overhanging jaw after diameter expansion cutting, making it difficult to pull out the device from the hole. There is also.

This idea was created in view of the above points, and after drilling an enlarged hole in the wall of a drilled hole that has been drilled in advance in a material to be drilled such as concrete, it is difficult to prevent chips remaining in the hole. Therefore, it is an object of the present invention to provide a diameter-expanding hole drilling device that facilitates the hole wall cutting work and the automatic return of the cutting blade to its normal position, thereby improving workability.

Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

In the figure, 1 is a main body having a shank 2 connected to a drive shaft at the upper end, 3 is a wedge center,
The lower end portion of this wedge center 3 forms an overhanging jaw 4 which is gradually inclined outward from the main body side and overhangs. Reference numeral 5 denotes a hollow portion provided in the main body 1 with its lower end opened, and the wedge center 3 has a compression spring 6 interposed in this hollow portion 5 so that the wedge center 3 can rotate together with a common axis.
Moreover, it is inserted so as to be relatively movable in the axial direction within a predetermined range. Reference numeral 7 denotes a pair of plate pieces having appropriate elasticity that are formed facing each other by cutting the main body 1 at the lower part of the main body, and a cutting blade 8 is attached to the tip of the plate pieces, and engages with a guide groove 9 provided on the overhanging jaw surface to enable movement on the overhanging jaw.

However, the cutting blade 8 is normally located at the base of the overhanging jaw of the wedge center 3, and due to the relative movement of the main body 1 and the wedge center 3 in the axial direction, the wedge center 3 moves against the spring 6 and moves into the hollow part 5 of the main body. By the movement of being drawn inward, the wedge center 3 is made to project outward from the overhanging jaws 4 along the overhanging jaws 4.

In the above structure, this invention provides a chip storage hole 10 that extends transversely to the overhanging jaw 4 of the wedge center 3, and temporarily stores chips generated by cutting the hole wall in the chip storage hole 10. The structure is such that it can be evacuated.

In the above embodiment, a chip collection hole 10 is provided that runs through the protruding jaw, and chips are evacuated. It may also be a department.

Next, the manner of use of the device of this invention having the above structure will be explained with reference to FIG.

As shown in Figure a, when cutting an enlarged diameter hole at the bottom of a pre-drilled blind end hole A, the lower end of the wedge center 3 inserted into the hole is brought into contact with the bottom of the hole.

From this state, when the main body 1 is rotated and pushed into the hole against the spring 6, the plate cutting blade 8, which was previously located at the base of the protruding jaw of the wedge center 3, While engaged with the guide groove 9 of the overhanging jaw 4, it moves outward along the guide groove 9 to start cutting the hole wall.
Finally, as shown in Figure b, the hole wall is cut to expand the diameter until the maximum overhang point of the overhanging jaw 4 is reached.
Delete.

Here, the chips C generated by the diameter expansion cutting of the hole wall are evacuated into the chip storage hole 10 provided in the overhanging jaw 4, and the work is continued, and the cutting blade 8 is removed from the overhanging jaw 4. After reaching the maximum extension point, when the pressing force on the main body 1 is released, the cutting blade 8 is moved in the reverse order of the above operation by the action of the spring 6 inside the body, as shown in Figure c. The device is returned to its normal position at the base of the overhanging jaw, and the device is then pulled out from hole A.

In this chip collection, the movement of the tip of the cutting blade reaches the maximum protrusion point of the protruding jaw, so the present enlarged hole drilling device is operated in the working direction in Fig. 3. Even when used for horizontal work in the orthogonal direction, as the cutting blade advances, the rotating tip of the cutting blade advances to the point where it opposes the opening of the chip pool, so the chips still flow into the chip pool. You will have to evacuate.

As explained above, according to the hole wall diameter expanding device of this invention, in order to plant an anchor bolt in concrete, etc., the hole wall of the hole previously drilled in the concrete surface is cut and the diameter expanded portion is cut. In achieving this,
Even if chips generated in the hole remain at the cutting work position, they are evacuated to the chip reservoir provided in the protruding jaw of the wedge center that guides the cutting blade in the hole. , it does not interfere with the progress of the hole wall cutting work, and even when the cutting blade moves on the overhanging jaw and returns to its normal position after finishing the cutting work, the chips get in the way and prevent the cutting blade from moving. It does not impede movement, and allows the work to be carried out smoothly from the start of the work to the end of the work, thereby improving work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the invention, FIG. 2 is a side view of a portion of the same essential parts, and FIGS. 3a, b, and c are explanatory views of the operation. 1... Main body, 2... Shank, 3... Wedge center, 4... Overhanging jaw, 5... Hollow part, 6... Compression spring, 7... Plate piece, 8... Cutting blade, 9... Guide Groove, 10...Chip collection section.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A wedge center is inserted into the main body so that the wedge center rotates together with the main body and the shaft is movable relative to the main body under the bias of a spring in the axial direction, and the wedge center is attached to the main body. The blade is moved to the tip of the wedge center along an overhanging jaw provided outwardly extending from the main body toward the tip of the tip, and is inserted into a pre-drilled hole so as to protrude outward from the overhanging jaw. A diameter expanding hole cutting device configured to cut a hole wall, in which the tip of the cutting blade moves up to the maximum protrusion point of the overhanging jaw, wherein the tip of the wedge center An enlarged diameter hole cutting device characterized in that a chip collecting portion is provided in the diameter enlarged hole drilling device. (2) The diameter enlarged hole drilling device according to claim 1, wherein the chip reservoir is formed by a hole extending transversely through the protruding jaw.