JP3088041B2 - Hole bottom expanding tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diameter expanding tool for expanding the bottom of a hole having a uniform diameter formed in concrete, stone or the like.

[0002]

2. Description of the Related Art When an anchor is driven into concrete or stone to fix it, it is general to increase the pull-out strength by expanding the bottom of a hole formed in advance in the hole.

FIG. 4 shows a conventional tool of this kind. That is, the tool 1 is a cylindrical housing 2 inserted into a hole H formed in advance in concrete or the like.
And a pair of large-diameter cutting blades 4, 4 supported at the tip of the housing so as to be pivotable about one pivot 3,
A diameter-enlarged cutting blade 4 having a cutting blade portion 5 at a first end which is a front end thereof, and mounted in the housing 2 so as to extend in the length direction with respect to the hole H, A drive shaft 6 for transmitting a rotational driving force to the large-diameter cutting blades 4, 4, and a pair of tips of the drive shafts which are inclined in opposite directions about a sharp edge 6 ′ extending to one diameter. Are formed and tapered, and each of the inclined surfaces 7 is a second end portion on the opposite side of the first end portion (tip) of each of the enlarged cutting blades 4 about the pivot 3. 8, 8 are engaged. When the drive shaft 6 is moved in the direction of the front end of the housing (in the direction of the arrow), the enlarged cutting blade 5 is pivotally moved in the opposite direction about the pivot 3 by the inclined surface 7 so as to spread. It has become.

[0004] A disadvantage of this tool is that it is not possible to obtain a sufficient expansion of the enlarged cutting blade 4, especially when the hole H into which it is to be inserted and therefore the tool has a small diameter. In order to sufficiently expand the diameter-enlarged cutting blade, if the length from the pivot 3 to the cutting blade 5 is made longer than the length from the pivot 3 to the second end on the opposite side, the drive A large thrust is required to push down the shaft 6, which makes the operation difficult.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tool which can solve the above-mentioned drawbacks of the conventional tool, is easy to operate, and can sufficiently expand the diameter. It is.

[0006]

That is, a tool according to the present invention is basically a hole bottom diameter expanding tool having the above-mentioned configuration, wherein a pair of inclined surfaces formed on a tip end surface of a drive shaft are provided. Are formed along one diameter at the tip end surface and inclined in opposite directions adjacent to each other over substantially the entire length of the same diameter.

In this tool, the second end of the diameter-enlarged cutting blade (the end opposite to the tip where the cutting blade is provided) is
Since the inclined surface extending over almost the entire length of the diameter of the drive shaft is moved from one end to the other end, the cutting blade portion at the tip is displaced and expanded in the diameter direction much more greatly than in the conventional one.

[0008]

An embodiment of the present invention will be described below with reference to FIG.
3 through FIG.

As shown in the figure, a tool 10 according to the present invention has a cylindrical housing 12 inserted into a hole H formed in a concrete or the like 11 and a tip (lower end) portion of the housing as described above. A pair of enlarged cutting blades 16, 16 pivotally supported about respective pivots (common pivots in the illustrated embodiment) 14, extending in the length direction with respect to the hole, and displaceable in the same direction. And a drive shaft 20 attached to the housing. The drive shaft 20 has a pair of mutually inclined slopes 24 that engage the upper ends 16 ′, 16 ′ of the enlarged cutting blades 16, 16. When the blade is moved toward the front end of the housing, the enlarged cutting blades 16 are pivotally opened in opposite directions about the pivot 14 by the action of the inclined surface. I have.

The housing 12 is formed in a cylindrical shape, and has an upper end for supporting the housing 12 so as to be rotatable inside the hole H when the tool is inserted into the hole H as shown in the figure. A rotation support device 30 is mounted. That is, this support device has an inner cylindrical member 32 fixed to the upper end of the housing 12 and an outer cylindrical member 36 rotatably mounted concentrically outside the inner cylindrical member via a bearing 34. The outer cylinder member 36 has a lower edge 36 ′ extending downward from the lower edge of the inner cylinder member 32 so that the outer cylinder member 36 comes into contact with the outer surface of the concrete C when the tool is inserted into the hole H. Has become. The holes 38 formed in the inner cylinder and the outer cylinder are for supplying cooling water when performing the diameter expanding operation.

[0011] The lower end of the housing is a closed end,
A diametrically extending groove 40 is formed in the center of the end, and the end is divided into left and right walls 12 ', 12' as viewed in FIG. The pivots 14 of the cutting blades 16, 16 are set.

The drive shaft 20 has a cylindrical stopper 42 set above the rotation supporting device, and a compression spring 44 set between the stopper and the inner cylindrical member 32. The spring 44 acts to lift the drive shaft 20 upward with respect to the housing 12 when the diameter expanding operation is not performed, and the stopper 42 has a lower end edge when the drive shaft is pressed down against the spring 44. Reference numeral 42 'abuts on the inner cylinder member (specifically, the bottom surface of the hole 32' of the inner cylinder member 32 into which the lower end edge is inserted) to prevent the drive shaft from being further pushed down. In the embodiment shown, the drive shaft 20 is provided with an elongated hole 46 extending transversely therethrough, through which a pin 48 is provided which extends through the housing 12 and extends therethrough. The drive shaft 20
Is transmitted to the housing via the pin 48.

The inclined surfaces 24, 24 of the drive shaft 20 are a feature of the present invention, and are opposed to each other on both sides except for one diameter portion 24 '(FIG. 3) at the distal end surface of the drive shaft. It is formed so as to be inclined. The upper ends of the enlarged cutting blades 16, 16 are engaged with the inclined surface at a position adjacent to the diameter portion 24 ′, so that when the drive shaft is pushed down from the position of FIGS. 1 and 3, The upper end is greatly displaced along one of the inclined surfaces 24, 24 from one side of the center of the drive shaft to the other side in the diameter direction beyond the center. In the embodiment shown, the inclined surface 2
4 and 24 are formed on the entire surface on both sides of the diameter portion 24 ', but what is actually required is only the portion where the upper ends 16' and 16 'of the cutting blades 16 and 16 engage. An inclined groove may be formed, and the bottom surface may be the inclined surface.

In the diameter increasing operation, the drive shaft is connected to a rotary drive device (not shown), and the rotary shaft is pressed down toward the bottom of the hole while being driven to rotate by the device. In this way, the inclined surfaces 24, 24 at the tip of the drive shaft are
The upper ends of 6, 16 are diametrically displaced from the position shown in FIG. 1 to the position shown in FIG. 3, whereby the cutting blade portion 22 at the lower end of the enlarged diameter cutting blade is pushed outward in the radial direction and rotated to rotate the side surface of the hole. And expand the diameter.

[0015]

The tool according to the present invention has the above-described configuration, and the inclined surfaces 24, 24 with which the cutting blades 16, 16 are engaged are formed over substantially the entire diameter of the drive shaft. Compared to a conventional tool which can be formed only within the radius of the drive shaft, the cutting blades 24, 2
Even if the length from the pivot 14 to the lower end of the fourth blade 4 is not excessively increased, the cutting blade portion 22 at the tip of the enlarged diameter cutting blade can be largely expanded in the hole side surface. Therefore, the operation is easier and the diameter can be greatly increased as compared with the conventional tool.

[Brief description of the drawings]

FIG. 1 is a cross-sectional front view of a state before a hole bottom expanding tool according to the present invention is inserted into a hole to be expanded and before a diameter expanding operation is performed.

FIG. 2 is a cross-sectional front view showing a state in which a diameter expanding operation of the tool is performed.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a sectional front view showing a main part of a conventional diameter expanding tool.

[Explanation of symbols]

12 --- Housing; 14 --- Axis; 16, 1
6 ---- Diameter cutting blade; 20 --- Drive shaft; 24, 24-
--- Slope.

Claims (1)

(57) [Claims] 1. A housing inserted into a pre-formed hole, and a pair of enlarged cutting blades supported at a tip portion of the housing so as to be pivotable about respective pivots. A diameter-enlarged cutting blade having a cutting blade portion at a first end, extending in the length direction with respect to the hole, displaceable in the same direction, and attached to the housing; A drive shaft for transmitting a rotational drive force to the cutting blade, the drive shaft having a second end at a tip thereof opposite to the first end with respect to the pivot of each of the enlarged cutting blades. Has a pair of inclined surfaces inclined in opposite directions to engage with each other, and is moved toward the front end direction of the housing, so that the action of the inclined surface allows the enlarged cutting blades to mutually move around the pivot. Pivot in opposite directions to oppose the cutting blades diametrically to each other In the hole bottom expanding tool adapted to be moved at a time, the inclined surface of the drive shaft is set at 1 in the tip end surface of the drive shaft.
Are formed so as to be inclined adjacent to each other and opposite to each other along one diameter and for almost the entire length of the same diameter
And the second end of each enlarged cutting blade engaging with each inclined surface.
The drive shaft is moved toward the front end of the housing.
When moving, each inclined surface is shifted from one end to the other end.
A hole bottom expanding tool characterized in that it can be moved together.