JPH063113B2 - Expansion bit - Google Patents

Description

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

<Prior art> After propelling a small-diameter pilot pipe in advance from the starting shaft to the reaching shaft, a large-diameter expanding bit is attached to the tip of this pilot pipe, and the pilot pipe is directed from the reaching shaft to the starting shaft. There is a method of burying a propulsion pipe while excavating a larger diameter hole.

The hole-expanding bit used in the above-mentioned construction method is composed of a funnel-shaped hollow cylinder, and a large number of chips for excavation, which are excavating means, are projected on the surface in the excavating direction. It has a structure that can drill large-diameter holes.

<Problems to be solved by the present invention> The excavation technique for expanding holes described above, when the excavated ground is hard rock such as boulders and boulders, the chips are likely to be worn out easily and easily chipped, so excavation work is difficult. It will be very difficult.

Therefore, the excavation efficiency tends to decrease and the construction period tends to be prolonged.

In addition, when it is judged that the rock excavation is impossible, the planning line must be changed, which requires a lot of time and cost.

<Object of the Present Invention> The present invention has been made in view of the above problems, and an object of the present invention is to provide a hole-expanding bit capable of efficiently and reliably excavating an expanded hole even in hard rock.

<Structure of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings. First, a hole-expanding bit used for excavating an expanded hole will be described.

<A> Configuration of Hole-Expanding Bit An example of the hole-expanding bit 1 is shown in FIGS.

This hole-expanding bit 1 is composed of a bottomed main body 2, an excavating means and an earth removing means provided in the main body 2. The bottom surface 2 of the main body 2
1 is completely closed and formed, and an excavation front face 22 facing the other bottom face is provided with an intake port 23 for taking in excavated earth and sand.

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

Therefore, the hole-expanding bit 1 rotates integrally with the rotation of the pilot pipe 3.

<B> Drilling Means The conventional drilling means for a hole-expanding bit utilizes propulsive force, but the hole-expanding bit 1 employs a drilling device 4 capable of excavating with little use of propulsive force.

This drilling device 4 uses, for example, compressed air for the drill head 4
A well-known down-the-hole drill for excavating 1 by pistoning can be adopted.

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

At this time, the drill device 4 inserts the drill head 41 into the inlet 2
It is stored by exposing it on the front surface 22 of the excavation, avoiding 3.

Although the installation position and the number of installations of the drill device 4 differ depending on the drilling diameter of the drilling hole, the drilling bit 1 of the drilling bit 1 can be passed through the entire range of the drilling front surface 22 except at least the pilot pipe 3. Drill head 4 from the axis
Install by shifting the installation position of 1. Further, in order to supply compressed air to the drill device 4, the hollow shaft 51 of the screw auger 5 inserted in the pilot pipe 3 is used as a compressed air supply path, and an air swivel 52 is provided at the tip of the screw auger 5. It is attached so that compressed air can be continuously supplied when the screw auger 5 is rotated.

<C> Earth Exhaust Means The earth and sand excavated by the drill device 4 is taken into the main body 2 through the intake port 23, and then transferred to the proximal end side of the pilot pipe 3 by the screw auger 5 rotating in the main body 2 to remove the earth. To do.

A plurality of inlets 23 are appropriately opened at positions displaced from the axial center of the hole-expanding bit 1 so that all the excavated earth and sand can be taken in.

Next, a method of excavating the enlarged hole will be described.

(1) Excavation of the guide hole (Fig. 3) First, the guide hole is excavated according to the planned line.

To excavate the leading hole, for example, the rotary propulsion device 6 is installed on the side of the starting shaft A, and the multi-drill 7 and the leading conduit 8 are set to perform the excavation.

In the excavation work of the leading hole, even if there are boulders on the excavated ground, the boulders can be easily penetrated by the multi-drill 7, so that the excavation along the planned line can be performed.

The excavation work is advanced while sequentially connecting the pyrotechnic pipes 3 having the screw augers 5 therein, and the excavation shaft B is excavated.

(2) Attachment of hole-expanding bit After the guide hole penetrating to the reaching shaft B is opened, the pilot conduit 8 is removed from the tip of the pilot pipe 3 and the hole-expanding bit 1 is replaced.

(3) Excavation of the enlarged hole (Fig. 4) On the side of the starting shaft A, supply of compressed air is started from the base end of the screw auger 5, and at the same time, the rotary propulsion device 6 is operated,
While giving rotation to the pilot pipe 3, it is pulled back to the starting shaft A side.

As a result, as shown in FIG. 1, the drill device 4 incorporated in the hole expanding bit 1 strikes the ground to excavate.

The drill head 41 revolves in response to the rotation of the pilot pipe 3, and sequentially drills the unexcavated portion 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, these rocks are crushed with high efficiency by the impact of the drill head 41 and the enlarged hole is excavated.

As a result, an enlarged hole having an enlarged hole diameter is excavated around the leading hole.

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

In parallel with the excavation work of the hole-expanding bit 1, the laid main pipe such as the fume pipe 9 is propelled from the reaching shaft B to the starting shaft A.

While repeatedly collecting the pilot pipe 3, the enlarged hole is excavated until the starting shaft A is reached.

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

(A) Even if the rock is hard, it can be crushed with a drill device without fail, so that it is possible to excavate an enlarged hole.

(B) By selecting the number of drilling devices and the number of installation positions, it is possible to efficiently drill even the largest holes.

(C) The conventional hole-expanding bit requires a large propulsion force because it is an excavation method that uses propulsion force.

According to the present invention, since it is possible to excavate the enlarged hole by hitting the drill device, it is not necessary to give a particularly large propulsive force to the enlarged hole bit.

Therefore, it is possible to use a rotary propulsion machine having a smaller propulsion capacity than the conventional one.

[Brief description of drawings]

 Fig. 1: Explanatory view of vertical cross section of hole expanding bit Fig. 2: Cross sectional view of II-II in Fig. 1 Fig. 3: Explanatory drawing of pilot pipe propulsion Fig. 4: Excavation of large diameter hole Illustration

Claims (1)

[Claims] 1. A pilot pipe is propelled through the ground from the starting shaft to the reaching shaft, and then a perforated bit is attached to the penetrating end of the pilot pipe to propel it from the reaching shaft to the starting shaft. A hole-expanding bit that is used in the construction method and that has an outer diameter larger than the outer diameter of the pilot pipe, and that performs hole-expansion by propelling while rotating together with the pilot pipe. A plurality of drilling devices that are housed inside and are hammered toward the starting shaft, a plurality of drill heads attached to the drilling front face of the hole expanding bit at the tip of the starting shaft side of this drilling device, and a drilling device The rotation locus of each drill head centered on the axis of the hole-expanding bit, which is generated by the rotation of the hole-expanding bit, is formed by the rotation of the hole-expanding bit. Characterized by being configured to pass through, reaming bit