JP3470766B2 - Ground drilling rig - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground excavator, and more particularly to a ground excavator suitably used for boring a soft ground. [0002] Conventionally, as a ground excavator, for example,
The structure shown in FIGS. 1 and 2 is known. The ground excavator shown by reference numeral 1 in these figures is constituted by a bit 2 for ground excavation, and a drill rod 3 attached to the tip of the bit 2 and inserted into the ground while rotating the bit 2. The bit 2 is formed by integrally attaching a plurality of chips 2b to the tip of a cylindrical body 2a. The drilling rod 3 is formed in a cylindrical shape like the bit 2, In the state where the bit 2 is attached, a continuous water supply hole 4 is formed inside. [0003] The ground excavator 1 rotates the bit 2 and the excavating rod 3 by appropriate driving means, and removes the bit 2 while sending water from the base end of the excavating rod 3 to the tip end of the bit 2. When the bit 2 is pushed into the ground, the ground is crushed by the bit 2, and the crushed rock fragments and the like are removed from the tip of the bit 2 by water fed from the water supply hole 4.
The excavation is performed while discharging to the surface through the outer peripheral surface of the excavation rod 3. [0004] By the way, in such a conventional excavator, slime generated by crushed rock fragments and water to be supplied at the outer peripheral portion of the tip of the bit 2 is as follows. There is a problem that clogging occurs between the inner surface of the hole and the bit 2, the water supply pressure rises rapidly, and this causes rock collapse of the inner surface of the hole. [0005] Also, as the excavation progresses, bit 2
Between the outer peripheral surface of the drilling rod and the inner surface of the drilled hole, the collapsed rock fragments clog and cause poor water supply,
Alternatively, the rock fragments and slime are turned into clay and bit 2
In addition, there arises a problem that the rotation of the excavating rod 3 is inferior. It is assumed that these problems not only reduce the excavation efficiency, but also make it impossible to discharge the slime in the excavation hole to the outside of the excavation hole, thereby making excavation itself impossible. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and prevents clogging of slime generated during excavation and ensures discharge of slime to the outside of a hole. The purpose is to make the rotation of the smooth. [0007] In order to achieve the above-mentioned object, a ground excavation apparatus according to the present invention comprises a ground excavation bit and a drill rod to which the ground excavation bit is attached. And projecting in the radial direction on the outer circumference of the bit and the drilling rod.
A plurality of arc-shaped raised portions forming a concentric circle with the outer peripheral surface are formed at intervals in the circumferential direction. According to the ground excavating apparatus of the present invention, the rock is crushed by the bit, and the crushed rock fragments are supplied to the bit by the water sent to the tip of the bit through the inside of the drill rod and the bit. It is carried upward along the outer circumference of the drill rod and discharged out of the hole. The rock or slime sent to the side of the bit and the drilling rod is transported upward while being stirred by the ridge provided on the outer periphery of the bit and the drilling rod. As a result, slime and rock fragments are prevented from being clogged and clayified, the bit and the drilling rod are smoothly rotated, water is reliably sent, and the slime is smoothly discharged out of the hole. An embodiment of the present invention will be described below with reference to FIGS. In FIG. 3, reference numeral 10 indicates a ground excavation apparatus according to the present embodiment.
Is a bit for ground excavation (hereinafter abbreviated as a bit) 11
And a drill rod 12 to which the bit 11 is attached. A plurality of raised portions 11a, 12a projecting in the radial direction are formed on the outer circumference of the bit 11 and the drill rod 12 at intervals in the circumferential direction. It has a schematic configuration. Next, the details of these will be described. As shown in FIG. 4, the tip of the bit 11 has an excavating tip 11b along the inner periphery thereof, and an excavating tip 11 projecting a predetermined length from the outer periphery. Of chips 11c are integrally mounted so as to be alternately positioned in the circumferential direction. In the present embodiment, the raised portions 11a are provided at three locations at predetermined intervals in the circumferential direction, as shown in FIG. When viewed as an angle around the rotation center of No. 11, the angle is set in a range of about 60 °. Further, the outer peripheral surface of each of the raised portions 11a is formed in an arc shape so as to form a concentric circle with the outer peripheral surface of the bit 11, and the chip 11c attached to the outer peripheral side has:
The chip 11 is provided at a position that is superimposed in the axial direction of the bit 11, and the outer peripheral surface of each raised portion 11 a is
It is retracted toward the center of the bit 11 from the outer peripheral surface of 1c. Further, as shown in FIG. 5, the raised portion 12a provided on the outer periphery of the
2 are provided at three locations at predetermined intervals in the circumferential direction, and the shape and height from the outer peripheral surface of the drilling rod 12 are different from those of the raised portion 1 provided on the bit 11.
1a. A water supply hole 13 similar to the conventional one is formed in the inside of the drilling rod 12 and the bit 11 so as to communicate with the whole length. Next, the operation of the embodiment constructed as described above will be described. The ground excavator 10 in the present embodiment includes a bit 11 and a drill rod 1 as in the prior art.
2 is rotated, and excavation is performed while sending pressurized water into the water supply hole 13 therein. [0015] The slime is generated at the tip of the bit 11 by rock pieces generated by the ground being crushed by the bit 11 and the supplied water, and the slime is generated by the water and is indicated by a chain line arrow in FIG. 3. Is transported upward along the outer peripheral surfaces of the bit 11 and the rod 12, and is discharged to the ground surface. In such a slime discharging operation,
The slime fed from the tip of the bit 11 to its side is agitated by the raised portions 11a and 12a which are rotated as shown by solid arrows in FIG.
The clay of the slime is prevented. As a result, at the time of excavation, an increase in rotational resistance to the bit 11 and the excavation rod 12 is suppressed, an increase in driving force required for excavation is suppressed, and an increase in flow path resistance in the slime discharge flow path is prevented. As a result, smooth transportation and discharge of slime and rock fragments are ensured. Moreover, since the slime is smoothly transported upward and discharged, not only is the water supply pressure properly adjusted, but also unnecessary pressure does not act on the excavated ground inner wall, thereby eliminating the inner wall. Is prevented from collapsing. As described above, according to the ground excavator 10 of the present invention, smooth slime conveyance and discharge can be ensured, and the water supply pressure for slime discharge can be controlled with high accuracy. As a result, an increase in excavation resistance due to the formation of clay is suppressed, and high-efficiency excavation is enabled, and rock collapse is suppressed, thereby improving excavation accuracy. Therefore, it is effectively used not only in the ordinary ground but also in excavation on soft ground. It should be noted that the shapes, dimensions, and the like of the components shown in the above-described embodiment are merely examples, and can be variously changed based on design requirements, for example, the shapes and installation positions of the raised portions 11a and 12a,
Alternatively, the number of installations and the like can be arbitrarily changed depending on the geology and the like of the ground to be applied. As described above, the ground excavation apparatus according to the present invention includes the ground excavation bit and the excavation rod to which the ground excavation bit is attached. Before projecting radially on the outer circumference of the rod
Concentric with the outer surface of the bit and drill rod
It is characterized by forming a plurality of arc-shaped raised portions at intervals in the circumferential direction, and has the following excellent effects. In the operation of discharging the slime generated during excavation, the slime sent from the tip of the bit to the side thereof is agitated by the raised portion, thereby preventing the slime from becoming clay. As a result, at the time of excavation, it is possible to suppress an increase in rotational resistance to the bit and the excavation rod, to reduce a driving force required for excavation, and to prevent an increase in flow path resistance in the slime discharge flow path. Thus, smooth conveyance and discharge of slime and rock fragments can be ensured. Moreover, the smooth discharge of the slime not only makes it possible to properly adjust the water supply pressure, but also prevents unnecessary pressure from acting on the excavated ground inner wall and causes its collapse. Can be prevented. Therefore, due to these synergistic effects, high-efficiency excavation can be performed, and rock collapse can be suppressed to improve excavation accuracy. Therefore, good excavation can be performed not only in the ordinary ground but also in the excavation on the soft ground.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional side view showing a conventional ground excavator. FIG. 2 is a front view showing a tip shape of a bit of a conventional ground excavator. FIG. 3 is a longitudinal sectional side view showing one embodiment of the present invention. FIG. 4 shows an embodiment of the present invention and is a front view of a bit. FIG. 5 shows an embodiment of the present invention, and is a plan view of a drilling rod viewed from an axial direction. [Description of Signs] 10 Ground excavation equipment 11 Bit 11a Raised portion 11b Tip 11c Tip 12 Drilling rod 12a Raised portion 13 Water hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E21B 10/02 E21B 17/22

Claims (1)

(57) [Claim 1] A ground drilling bit, and a drilling rod to which the ground drilling bit is attached, and protruding in the radial direction on the outer periphery of the bit and the drilling rod. Said
A circle forming a concentric circle with the outer peripheral surface of the bit and the drill rod
A ground excavation device comprising a plurality of arc-shaped raised portions formed at intervals in a circumferential direction.