JPH0324708Y2 - - Google Patents

Description

[Detailed explanation of the invention] a. Industrial application field This invention relates to an excavator.
This invention relates to an excavator equipped with a bit at the tip of a rod, which is used to enlarge the depth of a borehole.

b. Conventional technology As a technology for enlarging the deep part of boreholes such as blasting holes, crushing agent filling holes, anchor driving holes, etc. in tunnel excavation work and other civil engineering works, etc.
There are OJP construction methods, TKR construction methods, and construction methods that use high water pressure.

The OJP method uses a four-winged bottom expander that opens like an inverted umbrella to expand the deep part of a borehole.

In addition, in the TKR method, the deep part of the borehole is expanded using a widening bit that is widened by a hydraulic jack.

Furthermore, in the method of using high-pressure water, high-pressure water is vigorously jetted from the tip of the rod to enlarge the deep part of the borehole.

c. Problems that the invention aims to solve By the way, the conventional construction methods described above either require a complicated mechanical/hydraulic mechanism inside the bit, or require a special high-pressure generating mechanism separately outside.

Therefore, excavators that use the OJP method and TKR method have large bit diameters, and when using high-pressure water, installation space is required for drainage equipment and various external equipment associated with it. did.

Therefore, in order to solve the above problems, conventionally,
A bit is pivotally supported at the tip of the rod so that it can swing freely around an axis perpendicular to its rotating shaft, and as the rod rotates, the bit is tilted by the centrifugal force, thereby enlarging the deep part of the borehole. An excavator configured as follows has been proposed.

However, the bit of the above-mentioned excavator has generally been formed into a substantially plate shape so that a large excavation area can be obtained.

For this reason, a large-sized power generating device capable of generating large rotational power has become necessary for rotationally driving the bit. Therefore, there was a drawback that the excavator as a whole became larger.

In addition, when using the conventional excavator described above to excavate a hard rock layer using its approximately plate-shaped bit, the bit may be strained by the rock and excessive force may be applied to the bit, resulting in malfunction. There was a risk that it would break or break.

This invention was made in view of the above circumstances.
It is small, and it does not malfunction during excavation.
The purpose of the present invention is to provide an excavator that can be prevented from breaking.

d. Means for solving the problem In order to achieve the above object, in the present invention, a bit is pivotally supported at the tip of the rod so as to be able to swing freely about an axis perpendicular to the axis of rotation, and the bit is Accordingly, in an excavator configured to enlarge the deep part of a borehole by tilting the bit due to its centrifugal force, the tip of the bit is formed into a substantially conical shape, and a number of holes are formed on the circumferential surface of the drilling machine. It has a structure with protrusions.

e Example Hereinafter, an example of the excavator according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an exploded view of a bottom expander 1, which is a main part of an excavator according to this embodiment.

That is, the bottom expander 1
A rod 3 rotated by a drive means (not shown) installed outside the rod (see Figures 3 to 3), a pedestal 4 fixed to the rod, and a bit 5 pivotally supported by the pedestal. Consists of.

A male thread 3a is formed at the tip of the rod 3.

The threading direction of this male screw 3a is preferably the same direction as the rotational direction of the rod 3, but it may be in the opposite direction to the rotational direction of the rod so as not to make attachment and detachment of the pedestal 4 difficult.

A female thread 4a is formed at one end of the pedestal 4, and arms 4b and 4c are protruded from the other end of the pedestal, and a recess 4d is formed between these arms 4b and 4c.

A hole 4e is provided in a straight line to protrude from the arms 4b, 4c.

The bit 5 is integrally formed and has a support portion 5a at one end and a tip portion 5b at the other end.

A hole 5c is provided in a protruding manner in the support portion 5a. Note that 6 is a pin.

The bit body 5b is formed into a substantially conical shape and has a large number of protrusions 5d on its circumferential surface.

The male thread 3a of the rod 3 is screwed into the female thread 4a of the pedestal 4, the support part 5a of the bit 5 is fitted into the recess 4d of the pedestal, and the pin 6 is inserted through the holes 4e, 5c.

As a result, rod 3, pedestal 4 and bit 5
are integrated, and the bit 5 is inserted into the hole 4 of the pedestal 4.
It is installed so that it can swing freely around the axis e.

It should be noted that the device for rotationally driving the rod 3 is a well-known technique, so a detailed explanation thereof will be omitted.

Next, the operation of this embodiment will be explained with reference to FIGS. 2 to 4.

A borehole 2 is drilled in advance using an ordinary bit, and the bottom expander 1 according to the present embodiment is inserted and installed deep into the borehole 2, and the rod 3 is inserted while being pressed.
(See Figure 2).

Then, the bit 5 is urged toward the side circumferential wall 2a of the borehole 2 by the pressing force, and as the rod 3 rotates, the bit 5 begins to crush and excavate the side circumferential wall (see Fig. 3). .

In this case, in the excavator of this embodiment, the tip 5b of the bit 5 has a substantially conical shape, so that when digging a hard rock layer, the bit 5 may get stuck and an unreasonable force may be applied. However, due to the force applied to its circumferential surface, the bit 5 automatically swings to the opposite side to release the force, thereby minimizing malfunction or breakage. . Moreover, since there is no need for a large device that generates a large amount of power to rotate the bit 5, the entire excavator can be downsized.

By continuing to excavate in this way, the deep part of the borehole 2 is enlarged to form an enlarged bottom part 7 (see FIG. 4).

In addition, in order to perform excavation work more efficiently, an air outlet may be provided on the front surface of the pedestal 4 (on the side where the bit 5 is installed), or the pedestal 4 may be constructed of multiple pedestals. It is also possible to configure the pedestal so that it can be used in one or more stages depending on the excavation work.

f. Effect of the invention As explained above, according to the excavator according to the invention, the tip of the bit rotatably supported at the tip of the rod is formed into a substantially conical shape, and a number of bits are formed on the circumferential surface of the bit. Because the bit has a structure with protrusions, even if unreasonable force is applied to the bit due to it being hit by a rock when digging in a hard rock layer, the bit will not move due to the force applied to its circumferential surface. In order to automatically swing to the opposite side and release that force,
This prevents malfunction or breakage.

Moreover, since there is no need for a large device that generates a large amount of power to rotate the bit 5, the entire excavator can be downsized.

Furthermore, since the bit has a structure in which a large number of protrusions are provided on the circumferential surface of the bit, while maintaining the above-mentioned effects,
Excavation performance can be improved.

[Brief explanation of the drawing]

Figures 1 to 4 show the main parts of an embodiment of an excavator according to the present invention. Figure 1 is an exploded perspective view of the excavator, and Figures 2 to 4 sequentially show the operation of this embodiment. FIG. 1...bottom expander, 2...boring hole, 3...rod, 4...pedestal, 5...bit.

Claims (1)

[Scope of utility model registration request] A bit is pivotally supported at the tip of the rod so as to be able to swing freely around an axis perpendicular to the axis of rotation, and as the rod rotates, the bit is tilted by the centrifugal force, thereby enlarging the deep part of the borehole. In the excavator constructed as above, the tip of the bit is formed into a substantially conical shape, and a number of protrusions are provided on the circumferential surface of the bit.