JPH0254084A - Earth drill - Google Patents

Abstract

PURPOSE:To simplify work and improve the efficiency of the work and shorten the term of construction by arranging spiral blades on the outer peripheral section of a shaft connected attachably or removably to the lower end of a kelly bar, and by arranging a plurality of bits saliently downward along the external edge of the lower end section of the blades. CONSTITUTION:On the outer peripheral section of a shaft 10 having a joint 9 for being connected to the lower end section of a kelly bar, a spiral blade 11 is firmly fitted to be set by approx. 2 pitch component, and on its lower section, another spiral blade 12 is set by approx. half a pitch component phase- shifted by 180 deg. from the blade 11. Besides, along the external edges 11a, 12a of the lower sections of the blades 11, 12, a plurality of bar-shaped bits 13 are saliently arranged directed downward, and an earth drill 14 is composed. When a bedrock or the like is found under excavation by earth drill construction, then a rotary bucket is removed and the eath drill 14 is connected to and excavation is promoted again, and by consistent work with the same excavator used by the earth drill construction, excavation is efficiently executed.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to the invention when excavating the ground for constructing cast-in-place piles underground. This invention relates to an earth drill that is used to remove hard obstacles, such as buildings, by rotating them in a drill-like manner.

(Conventional technology) One of the cast-in-place pile construction methods is the earth drill method in which the ground is excavated using a rotating packet. If there are hard obstacles such as
- Once the excavation with the rotating packet is stopped, the underground obstruction is removed by another conventional obstruction removal means (for example, impact crushing means, etc.).

(Problem to be solved by the invention) However, as mentioned above, in order to remove obstacles during the earth drilling method, it is necessary to temporarily remove the drilling equipment using rotating packets, making it impossible to perform the entire work. Therefore, there were problems in that it required a lot of work, was troublesome, and also took a long time.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, a spiral blade is provided on the outer periphery of a shaft that can be detachably connected to the lower end of the Kelly bar, and the spiral blade is The earth drill is constructed by providing a large number of bits projecting downward along the outer edge of the lower end.

(Function) In the present invention, since the earth drill is configured as described above, when a hard obstacle is encountered in the ground during excavation using the earth drill method, the excavator that previously rotated the rotary packet can At the same time, remove the rotating packet from the Kelly bar, connect the earth drill of the present invention to the Kelly bar, reinsert the Kelly bar into the drilling hole, and press it against the obstacle with a large thrust while rotating the earth drill at the lower end. .

In this way, the earth drill of the present invention has a spiral blade provided on the outer periphery of the shaft, and a large number of bits are provided to protrude downward along the outer edge of the lower end of the spiral blade. Hard obstacles are cut by an earth drill that rotates with a Kelly bar.

After cutting the obstacle, the excavator's kelly bar
The earth drill is removed from the lower end of the Kelly bar, and the rotary packet is connected to the lower end of the Kelly bar again and inserted into the excavated Omukai area to perform excavation work.

As described above, according to the present invention, even if there is a hard obstacle in the ground, a pile hole can be efficiently excavated by an integrated operation using an excavator used in the earth drilling method.

Therefore, according to the present invention, not only the work becomes easier and efficiency is improved, but also the construction period can be shortened.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Third
The figure shows an example of an excavator used in the earth drilling method.

In the figure, 1 is the ground, 2 is the excavator of the crawler crane 2, 3 is the crawler, 4 is a swivel base installed on the crawler 3 so that it can be rotated freely, 5 is a crane boom that is attached to the swivel base 4 so that it can be raised and lowered, and 6 is a crane boom attached to the swivel base 4. A Kelly bar 7 suspended from the tip of the crane boom 5 is a rotation drive device (hydraulic type) for the Kelly bar 6, and 8 is a connecting arm that connects this rotation drive device 7 and the swivel base 4.

FIG. 1 shows details of the earth drill of the present invention. In this embodiment, the joint 9 is formed into a hollow cylindrical shape so as to be able to fit with the lower end of the Kelly bar 6, and has a connecting hole 9a. , is fixed to the upper end of a round bar-shaped shaft 10, and the lower end portion 10a of this shaft 10 is formed to have a small diameter via an inclined stepped portion 10b.

Further, a spiral blade 11 is fixed to the outer circumference of the shaft 10 by about two pitches, and another spiral blade 12 is fixed to the lower part of this spiral blade 11 by about a hand pitch in an area corresponding to about half a pitch. It is fixedly provided on the outer circumference of the shaft 10 with a phase shift of 180 degrees from the spiral blade 11. In this case, as shown in FIG. 1(b), the outer edge 11 of the lower end of the spiral blade 11.
It is preferable that the shapes of a and 12a are approximately S-shaped.

In this embodiment, the spiral blades 11°12
A large number of rod-shaped bits 13 (see FIG. 2) are placed along the outer edges 11a, 12a of the lower end of the blade, with the pointed end 13a facing downward and the body 13b buried in the blade 11.12. The earth drill 14 is configured by arranging the drills at intervals.

In addition, the bit 13 is preferably one whose cutting edge is made of an ultra-hard material such as diamond, especially for hard rock.
For softer materials, those using Kennemetal (trade name made in the United States) are suitable.

In the present invention, since the earth drill 14 is configured as described above, when a hard obstacle is encountered in the ground during excavation using the earth drill method, the rotary packet (
The rotating packet is removed from the Kelly bar 6 of the excavator 2 which was rotating the earth drill 1 of the present invention.
4 to the lower end of the Kelly bar 6 as shown in Fig. 3, insert the Kelly bar 6 into the excavated hole la again, and press it against the obstacle with a large thrust while rotating the earth drill 14 at the lower end. .

In this way, the earth drill 14 of the present invention has a shaft 1
A spiral blade 11.12 is provided on the outer periphery of the spiral blade 1111.12, and a large number of bits 13 are provided to protrude downward along the outer edges 11a and 12a of the lower end of the spiral blade 1111.12. A hard obstacle is cut by the earth drill 14 which rotates together with the ground drill. After cutting the obstacle, the Kelly bar 6 of the excavator 2 is lifted out of the way, the earth drill 14 is removed from the lower end of the Kelly bar 6, and the rotary packet is connected to the lower end of the Kelly bar 6 again. The excavation work will be carried out by inserting it into the excavated Omukai area.

(Effects of the Invention) As described above, according to the present invention, even if there is a hard obstacle in the ground, it is possible to efficiently drill a pile hole through an integrated operation using an excavator used in the earth drilling method. can.

Therefore, according to the present invention, excellent effects can be obtained in that the work is simplified and efficiency is improved, and the construction period can also be shortened.

[Brief explanation of the drawing]

FIG. 1(a) is an elevational view of the earth drill of the present invention, and FIG. 1(b)
) is a bottom view of the bit, FIG. 2(a) is an elevational view of the bit, FIG. 2(b) is a plan view thereof, and FIG. 3 is an elevational view of an excavator equipped with the earth drill of the present invention. 1... Ground 5... Crane boom 9... Joints 11, 12... Spiral blades 14... Earth drill

Claims (1)

[Claims] 1. A spiral blade is provided on the outer periphery of a shaft that can be detachably connected to the lower end of the Kelly bar, and a number of bits are provided protruding downward along the outer edge of the lower end of the spiral blade. earth drill.