JPS6375294A - Pit expanding bit - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a hole-expanding bit for drilling a large-diameter hole in the ground such as hard rock, cobblestone layer, and gravel layer.

<Conventional technology> After a small-diameter pilot pipe is propelled in advance from the starting shaft to the destination shaft, a large-diameter hole-expanding bit is attached to the tip of this pilot pipe, and the pilot pipe is propelled from the reaching shaft side toward the starting shaft. There is a method of burying the propulsion pipe while excavating a larger diameter hole.

The hole-expanding bit used in the above-mentioned method consists of a hollow funnel-shaped cylindrical body, and a large number of drilling tips, which are the drilling means, are protruded from the surface facing the excavation direction. The structure allows drilling large diameter holes.

Problems to be Solved by the Present Invention> The above-described hole-expanding drilling technique is difficult to perform when the drilling ground is hard rock such as boulders or boulders because the tips are subject to severe wear and are easily damaged. It becomes very difficult.

As a result, excavation efficiency tends to decrease and construction periods tend to become longer.

Furthermore, if it is determined that rock excavation is impossible, there is a problem in that the planned line must be changed, which requires a great deal of time and expense.

OBJECTS OF THE INVENTION The present invention was made in view of the above-mentioned problems, and it is an object of the present invention to provide a hole expanding bit that can efficiently and reliably drill an expanded hole even in hard rock.

Structure of the Present Invention> Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a hole expansion bit used for drilling an enlarged hole will be described.

〉Configuration of hole expanding bit An example of the hole expanding bit 1 is shown in Fig. 1.2.

This hole-expanding bit 1 consists of a bottomed body 2, and excavation means and earth removal means installed inside the body 2.

The bottom surface 21 of the main body 2 is completely closed, and the excavation front surface 22 facing the other bottom surface is formed with an intake port 23 for taking in excavated earth and sand.

Then, the excavation front surface 22 of the main body 2 is fixed to the tip of the pilot pipe 3 with the excavation front surface 22 facing in the direction of excavation of the hole expansion.

Therefore, the hole expanding bit 1 rotates together with the rotation of the pilot tube 3.

Excavation>Drilling means The drilling means of conventional hole-drilling bits utilizes propulsive force, but the hole-drilling bit i employs a drill device 4 that can drill with almost no propulsive force.

This drill device 4 uses, for example, compressed air to drill the drill head 4.
A known down-the-hole drill that excavates by making a piston move can be used.

That is, a plurality of holes are arranged in the main body 2 parallel to the axis of the hole expanding bit 1.

At this time, the drill device 4 takes the drill head 41 into the inlet 2.
It is exposed and stored on the excavation front face 22 avoiding 3.

The installation position and number of drill devices 4 will vary depending on the drilling diameter of the hole to be drilled, but the number of drill devices 4 to be installed will vary depending on the drilling diameter of the hole to be drilled. Drill head 4 from the axis of 1
Install by shifting the installation position of step 1.

In order to supply compressed air to the drill device 4, the hollow shaft 5 of the screw auger 5 inserted into the pilot pipe 3 is
1 is used as a compressed air supply path, and an air swivel 52 is attached to the tip of the screw auger 5, so that compressed air can be continuously supplied when the screw auger 5 rotates.

<C> Soil removal means The earth and sand excavated by the drill device 4 are taken into the main body 2 through the intake port 23, and then transferred to the base end side of the pilot pipe 3 by the screw auger 5 rotating within the main body 2 and removed. do.

A plurality of intake ports 23 are provided at positions offset from the axis of the hole-expanding bit 1 so as to take in all the excavated earth and sand.

Next, a method for drilling an enlarged hole will be explained.

(1) Drilling of pilot hole (Figure 3) First, drill a pilot hole along the planned line.

To drill a pilot hole, for example, a rotary propulsion device 6 is installed on the starting shaft A side, a multi-drill 7 and a pilot pipe 8 are set, and drilling is performed.

In the drilling work of the pilot hole, even if there are boulders in the excavated ground, the multi-drill 7 can easily penetrate the boulders, so that the drilling can be carried out along the planned line.

The excavation work is proceeded while sequentially connecting the pilot pipe 3 containing the screw auger 5, and the excavation is carried out to the reaching shaft B.

(2) Attachment of the hole expansion bit: Once a pilot hole penetrating to the reaching shaft B is opened, the pilot pipe 8 is removed from the tip of the pilot tube 3 and the hole expansion bit 1 is replaced.

(3) Excavation of an enlarged hole (Fig. 4) In the starting shaft A914, start supplying compressed air from the base end of the screw auger 5, and at the same time operate the rotary propulsion device 6 to give rotation to the pilot pipe 3. Pull back to the starting shaft A side.

As a result, as shown in FIG. 1, the drilling device 4 built into the hole-expanding bit 1 hits the ground to perform drilling.

The drill head 41 rotates in response to the rotation of the pilot pipe 3 and sequentially excavates unexcavated portions around the pilot pipe 3.

The excavated earth and sand is transferred by the screw auger 5 in the pilot pipe 3 and discharged to the starting shaft A side.

Even if rocks such as boulders are present on the way, the blows of the drill head 41 crush these rocks with high efficiency to drill an enlarged hole.

As a result, an enlarged hole with an enlarged diameter is drilled around the pilot hole.

Since drilling with the hole-expanding bit 1 is performed by the drill device 4, a large propulsion force unlike the conventional drill is not required.

In parallel with the drilling work of the hole expansion bit 1, the laying main pipe such as the hump pipe 9 is propelled from the arrival shaft B toward the starting shaft A.

While repeating the recovery of the pilot pipe 3, an enlarged hole is drilled until it reaches the starting shaft.

Effects of the Present Invention> Since the present invention is as explained above, the following effects can be obtained.

(b) Even hard rock can be reliably crushed with a drilling device, so it is not impossible to drill an enlarged hole.

(b) By selecting the number and location of drill equipment, it is possible to drill holes, no matter how large, with high efficiency.

(c) Conventional hole-expanding bits use propulsive force for drilling, and therefore require large propulsive force.

In the present invention, since the enlarged hole can be drilled by the impact of the drilling device, there is no need to apply a particularly large driving force to the hole-expanding bit.

Therefore, a rotary propulsion machine with a smaller propulsion capacity than conventional ones can be used.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] A pilot pipe is propelled underground to penetrate from the starting shaft toward the reaching shaft, and then a hole expanding bit is attached to the penetrating end of the pilot pipe, and the pilot pipe is penetrated from the reaching shaft toward the starting shaft. A hole-expanding bit used in the propulsion method, which has an outer diameter larger than the outer diameter of the pilot pipe, and which propels and expands the hole while rotating integrally with the pilot pipe. Multiple drill devices housed inside the bit and hit toward the starting shaft; multiple drill heads attached to the front of the drilling bit of the hole expansion bit at the tip of the drill device on the starting shaft side; The rotation trajectory of each drill head about the axis of the hole-expanding bit, which is caused by the rotation of the hole-expanding bit, passes through the entire area of the front surface of the excavation except for the pilot pipe. A hole expanding bit, characterized in that it is configured to