JP2001164863A - Drilling hole partial expansion device - Google Patents

Abstract

(57) [Problem] To provide a large-diameter enlarged portion for retaining in an excavation hole for fixing anchor bolts or the like using mortar in a bedrock or concrete placing portion. A rotating cylinder (1) having a fixed flange (2) sharing a rotation center axis at a lower end portion, and a fixed flange (2).
And a pair of semi-disc-shaped bit bodies 4 and 4 rotatably provided between the support flange 5 and the fixed flange 2.
The bit bodies 4, 4 are respectively turned around a pair of screw shafts 3, 3 which are fixed at symmetric positions of the fixed flange 2 with respect to the rotation center axis and support the support flange 5 so that their linear surfaces are in contact with each other. Mounted movably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for partially expanding an excavation hole, which is used to provide an enlarged hole diameter portion in a part of an excavation hole provided in a hard rock or a concrete casting portion.

[0002]

Conventionally, in order to attach a reinforcing bar, an anchor bolt, or the like to a hard rock or a concrete casting portion, first, a drilling machine equipped with a diamond bit is used to excavate an elongated vertical hole at a mounting location. And then
An operation of inserting an anchor bolt or the like into the pit, filling the mortar and solidifying the mortar, and fixing the anchor bolt or the like to the pit is performed. However, if a strong tensile force acts on the anchor bolts or the like fixed to the bedrock or concrete placing part as described above, the problem occurs in that the hole wall of the excavation hole is smooth and the mortar comes out together with the solidified mortar. There was often a need for a solution.

[0003] The present inventor has found that in order to prevent the mortar from being pulled out, a retaining hole for the mortar should be provided in the excavation hole. The present invention has been completed by paying attention to the fact that the mortar is filled and solidified in the excavation hole including the enlarged hole diameter portion, and the solidified mortar portion present in the enlarged hole diameter portion is prevented from falling off. It is an object of the present invention to provide a novel drilling hole partial diameter increasing device which can easily provide a drilling hole enlarged portion in a drilling hole. Another object of the present invention is to provide a device for partially expanding a drilling hole which is convenient and can be used in place of a diamond bit in the above-mentioned ordinary drilling machine, and has a simple structure and high durability. is there.

[0004]

In order to achieve the above object, a partial diameter expanding device for a drilling hole according to the present invention is characterized in that a rotary flange having a fixed central axis fixed at its lower end is fixed. A cylinder, a support flange disposed opposite to the fixed flange, and a pair of semi-disc-shaped bit bodies rotatably provided between the support flange and the fixed flange. The pair of bit bodies are rotatably mounted on a pair of screw shafts that are fixed to symmetric positions of the fixed flange with respect to the rotation center axis and support the support flange so that their linear surfaces are in contact with each other. Configuration.

According to this configuration, when the rotary cylinder is attached to the rotary shaft of the drilling machine, inserted into a drilled hole such as a rock which has already been drilled, and rotated, the pair of bit bodies are expanded by centrifugal force. As a result, the drilling operation in the direction orthogonal to the excavation hole is performed in the range of the width corresponding to the thickness of the bit body cutting edge. This drilling operation is completed when the bit body is fully expanded, and a part of the drilling hole (preferably below the drilling hole)
Is provided with a hole diameter enlarged portion corresponding to the distance between the two cutting edges when the bit body is fully expanded. In order to overcome the resistance of the hole wall and promote drilling work of the bit body to perform drilling work without hindrance, a tension spring is stretched between both bit bodies so that both bit bodies move in the expanding direction to each other. It is also possible to implement it so that it is always energized. In the case where a tension spring is provided, the bit bodies are pulled toward each other against the tension spring to form a disk, and then inserted into the borehole.

[0006]

Embodiments of the present invention will be described below. Reference numeral 1 denotes a rotary cylinder, the upper half of which is formed in a connection cylinder 1a provided with a female screw 1b capable of screwing with a rotation shaft of a normal drilling machine (a part is indicated by a virtual line). A fixed flange 2 is fixed to the lower end of the rotary cylinder 1 so as to share the rotation center axis with the rotary cylinder 1, and the fixed flange 2 is positioned symmetrically with respect to the rotation center axis. A pair of screw shafts 3 and 3 are fixed by screwing.

The screw shafts 3 and 3 have respective straight surface portions 4
a, a pair of semi-disc-shaped bit bodies 4,
4 is rotatably mounted and supports the supporting flange 5 corresponding to the fixed flange 2 in a state of being circumscribed to the bit bodies 4 and 4.
The support flange 5 has screw shafts 3 and 3
Are held by screwing holding nuts 6, 6 respectively. Then, the holding nuts 5, 5 are tightened so as not to hinder the turning operation of the bit bodies 4, 4, and the bit bodies 4, 4 are loosely clamped between the fixed flange 2 and the support flange 5.

[0008] The cutting edge formed by brazing diamond to approximately one-third of the arcuate surface portion 4b, with the arcuate surface portions 4b of the bit bodies 4, 4 facing each other from one end thereof. A part 7 is provided. Each of the linear surface portions 4a of the bit bodies 4, 4 is provided with an inclined groove 8 descending to the cutting edge portion 7 along the length direction of the linear surface portion 4a. Accommodates tension springs 9 hung on the bit bodies 4 and 4 at the deep side of the inclined groove 8, respectively. Numeral 11 denotes a hook portion (set screw or the like).

Due to the presence of the tension spring 9, the bit bodies 4, 4 are constantly urged toward the direction of expanding with the screw shafts 3, 3 as fulcrums (see FIG. 6). In cooperation with the centrifugal force acting on the body 4, the spreading operation of the bit body 4 can be promoted against the resistance of the hole wall. The outer diameters of the fixed flange 2, the support flange 5, and the bit bodies 4 and 4 (see FIG. 5) when formed in a disk shape are the same, and the rotation angle of the bit body 4 is the center of rotation. Is regulated by the length of a perpendicular line that falls on the linear surface portion 4a. In the figure, reference numerals 2a and 5a denote recesses provided in the fixed flange 2 and the support flange 5 for escaping the cutting edge 7, respectively, 2b a cooling water supply hole, and 12 a washer.

[0010]

The present invention is as described above, and it is possible to easily provide an enlarged diameter portion for retaining a mortar-attached anchor bolt or the like in a drilling hole. There is a handling advantage that a rotating mechanism can be used. In addition, the drilling function part is a simple structure in which a pair of semi-disc-shaped bit bodies are rotatably provided so that their straight surface portions are in contact with each other. Can be provided easily and inexpensively, and its practical value is extremely large.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention, in which a half part is shown in a cross section in a state where a bit body is closed.

FIG. 2 is a cross-sectional view of FIG. 3 taken along the line AA and viewed from the direction of the arrow.

FIG. 3 is a bottom view in which components on the bit body side are removed from those shown in FIG. 1;

FIG. 4 is an exploded perspective view of the bit body-side constituent member shown in FIG. 1;

FIG. 5 is a plan view in which the bit body shown in FIG. 1 is closed.

FIG. 6 is a plan view in which the bit body shown in FIG. 1 is expanded.

[Explanation of symbols]

 1 is a rotary cylinder 2 is a fixed flange 3 is a screw shaft 4 is a bit body 4a is a linear surface portion 5 is a support flange 6 is a holding nut 7 is a blade edge 8 is an inclined groove 9 is a tension spring

Claims (2)

[Claims] 1. A rotating cylinder having a fixed flange fixed to a lower end portion sharing a rotation center axis, a support flange disposed opposite to the fixed flange, and a support flange and the fixed flange. A pair of semi-disc-shaped bit bodies that are rotatably provided between the pair of bit bodies, and the pair of bit bodies are in contact with their linear surfaces so that the fixed flange is fixed to the rotation center axis. Characterized in that it is rotatably mounted on a pair of screw shafts fixed at symmetrical positions and supporting a support flange, respectively. 2. A part of a drilling hole according to claim 1, wherein the pair of bit bodies are urged toward each other in the expanding direction by extending a tension spring between the two bit bodies. Diameter expansion device.