JPH09112175A - Casing excavation bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the reaming bit to be left in the bottom of a hole by permitting the reaming bit to be dismounted from the center bit after the excavation conducted by the use of a ring-shaped reaming bit. SOLUTION: The tip end of an inner tube 20 is put in screw contact with a center bit 30 and inserted into the outer tube 10, and a lock-shaped piece 44 of a ring-shaped reaming bit 40 is passed through the cut part 31 of an impact ring 31 of the ring-shaped reaming bit 40 in a state of the bit part 32 projecting from the outer tube, and then the projection 44b is permitted to engage with the recess 31b. In this state, the outer tube 10 and inner tube 20 are secured to the boring device, after that, the inner tube 20 is put into actions of rotation, advance, impacts or the like, and the outer tube 10 is advanced to be rotated leftward. At the point of boring to a predetermined depth, when the inner tube 20, i.e., the center bit 30 is rotated rightward, the center bit 30 rotates at the distance of the dismounting amount 34 of the center bit 30 so that the projection 44 of the lock-shaped piece 44 of the ring-shaped reaming bit 40 is dismounted from the recess 31b, as a result, when the center bit 30 is lifted up as it were, the ring-shaped reaming bit 40 is left in the bottom of the hole, and then the inner tube 20 and center bit 30 are lifted up therefrom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casing for drilling holes in a collapsible soft ground while accommodating an outer pipe as a casing pipe in a mine, civil engineering work, etc., and for drilling a hard rock ground therebelow. It is about digging bits.

[0002]

2. Description of the Related Art Drilling of soft ground to the extent that the drilling hole does not stand after the rock bit is attached to a boring machine or a rock drilling machine and the ground drilling hole is extracted is conventionally classified into the following two types.
Different types of drilling tools were used. One is a double pipe bit, the outer pipe is almost equal to the inner diameter of the pipe, a ring bit larger than the outer diameter of the outer pipe is screwed, and the inner pipe is screwed with a bit smaller than the inner diameter of the outer pipe. At the same time, the inner tube was pulled out after reaching a predetermined depth by rotating or striking and rotating to feed.

The other one is to install an over-burten bit or a retract bit (see Japanese Examined Patent Publication No. 3-21717 and Japanese Patent Laid-Open No. 4-41891) whose diameter expands or contracts depending on the rotating direction at the tip of the inner pipe. Inserted into the outer tube in this state, project the bit from the tip of the outer tube, drill a hole slightly larger than the outer tube, and after drilling, reverse the inner tube to reduce the bit diameter and It was the one to pull out the tube.

[0004]

However, although the double pipe bit is suitable for drilling soft ground, it has a compressive strength of 800.
Drilling of hard rock ground exceeding Kgf / cm ² causes an extremely low drilling speed, and further casing (outer pipe)
Requires an expensive thick-walled steel pipe to transmit the impact and rotation.

When the over-burten bit and retract bit are reversed after drilling to reduce the bit diameter,
Since the hole-expanding bit is free, there was a case where the bit diameter was not reduced by catching powder with the bit body.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a casing digging bit which eliminates the conventional drawbacks by constructing a ring-shaped hole-expanding bit after boring at the butt end. It is a thing.

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to an outer tube, and a diameter of the outer tube, which is slightly larger than the outer diameter of the outer tube. And a ring-shaped hole-expanding bit that extends downward from this, has a U-shaped cross section, and one of the tips extends in the circumferential direction to form a protrusion, and the proximal end is connected to the inner pipe, A center bit provided with a striking ring in which a bit portion at the tip projects from a through hole of the ring-shaped expanded hole bit, and a plurality of notches through which the extending portion of the key-shaped piece passes is arranged in the middle. The ring lower surface of the ring-shaped hole expanding bit comes into contact with the tip of the outer pipe, the extending portion of the key-like piece passes through the notch of the striking ring in the outer pipe, and the projection is recessed in the striking ring. It is characterized in that the notch is detachably locked.

Therefore, when the key-like piece of the ring-shaped hole-expanding bit is drilled while rotating in the direction in which it engages with the recessed portion of the striking ring of the center bit, torque is applied to the ring-shaped hole-expanding bit and when it rotates in the reverse direction. , The protrusion at the tip of the key-shaped piece comes out of the recessed part of the striking ring, so when the inner pipe is pulled out, the center bit is pulled out through the hole of the ring-shaped expanded hole bit and pulled up, so Remain.

Further, the center bit of the present invention is characterized in that a through hole and a plurality of water holes, which communicate with the through hole from the outer periphery near the tip of the bit portion, are bored in the shaft center.

Therefore, it is possible to make holes while discharging the cutting fluid from the center bit through the inner pipe, and discharge the generated dust powder to the ground from the gap between the inner and outer pipes through the dust discharge unit.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a state in which a ring-shaped hole-expanding bit is engaged with a center bit in an embodiment of the present invention, (a) is a plan view, and (b) is a view taken along the line BB of (a). , (C) is a cross-sectional view taken along the line CC of (b), and (d) is a cross-sectional view taken along the line A-A-A of (a).

FIG. 2 shows an embodiment of the present invention in which the center bit and the ring-shaped hole-expanding bit are disengaged, (a) being a plan view and (b) being (a). FIG. 6C is a sectional view taken along the line DD of FIG.

Reference numeral 10 denotes an outer pipe, and in this embodiment, a vinyl chloride pipe is used. Reference numeral 40 denotes a ring-shaped hole-expanding bit having an outer diameter slightly larger than that of the outer tube 10, a through hole 41 (d in FIG. 1) being bored in the axial center, and a cemented carbide button bit 42 on the upper surface. It is planted. Further, groove-like powder-removing parts 43 are provided at three locations on the outer periphery, and downwardly from this, there is formed a key-like piece 44 having a U-shaped cross section and one of the tips extending in the circumferential direction to form a projection 44b. It has been extended.

This key-like piece 44 is shown in FIG.
In the case of the boring shown in (b) and (c), the projection 44b protruding through the notch 31a of the striking ring 31 of the center bit 30 to one side of the tip has a recessed portion 31b of the striking ring 31.
Is engaged with. Then, the key-like piece 44 in the drilled hole comes into contact with the notch 31a of the center bit 30 rotating counterclockwise at the surface 31c, and receives the rotation torque from the center bit 30. Further, the feeding force to the center bit 30 is given to the lower surface 45 of the ring-shaped hole expanding bit 40 by the upper surface 31d of the striking ring 31. Although there is a gap 46 in FIGS. 1B and 1D, both surfaces 31d and 45 are in contact with each other during drilling, and the projection 44b of the key-shaped piece 44 is axially extended from the recess 31b of the striking ring 31. Have left.

The projections 44b and the recessed portions 31b are for preventing the ring-shaped widening bit 40 from falling, so that the projections 44b and the recessed portions do not drop even if the inner pipe 20 is pulled up during drilling or after assembly. It is configured so that it does not disengage with 31b. The center bit 30 has a bit portion 32 protruding through a through hole 41 at the center of the ring-shaped expanded hole bit 40, the base end being screwed to the inner pipe 20 with a screw 21, and the tip being a superalloy cross bit. Has become. Rotate the inner tube 20 from the ground,
Drilling is performed by feeding or striking, rotating, and feeding.

FIG. 2 is a view showing a state in which the ring-shaped hole expanding bit 40 is removed. When the inner tube 20 is pressed against the bottom of the hole and rotated clockwise, the state shown in FIG.
It is a position deviated from b.

A through hole 33 is formed in the center of the center bit 30.
A plurality of water holes 32a are formed in the through hole 33 from the outer periphery near the tip of the bit portion 32, and the inner pipe 20
The cutting water is supplied through the inner pipe 20 and the outer pipe 10 through the U-shaped extending portion 44a of the key-shaped piece 44 from the dust-removing portion 43.
It is discharged to the ground through the gap 11.

To operate using the casing digging bit of the present invention, the following is done. First, the center bit 30 is screwed onto the tip of the inner pipe 20, is inserted into the outer pipe 10, and the key-shaped piece 44 of the ring-shaped widening bit 40 is attached to the center bit 30 with the bit portion 32 protruding from the outer pipe 10. Through the notch 31a of the striking ring 31 of FIG.
1b (FIG. 1).

In this state, the outer pipe 10 and the inner pipe 20 are attached to a boring device or a rock drill, and the inner pipe 20 is rotated,
Feeding, striking, rotating, feeding, and feeding the outer tube 10. In the case of the structure shown in the figure, the inner tube 20 is rotated counterclockwise.
At this time, the center bit 30 and the ring-shaped hole expanding bit 40
The relationship with is as shown in (b) and (c) of FIG.
Since the surfaces 31c are in pressure contact with each other, the torque of the inner pipe 20, that is, the torque of the center bit 30 is reduced to the ring-shaped hole expanding bit 40.
Is transmitted to At this time, the upper surface 31 of the striking ring 31
Since d and the lower surface 45 of the ring-shaped hole expanding bit 40 are also in pressure contact with each other, the feeding force applied to the inner pipe 20 is also transmitted to the ring-shaped hole expanding bit 40 and the hole is drilled.

When the hole is drilled to a predetermined depth, the inner pipe 20
When the inner pipe 20, that is, the center bit 30 is rotated clockwise (in the direction of arrow e in FIG. 1 (c)) while pressing the bottom end of the hole, the center bit 30 removes the removal allowance 3 shown in FIG. 1 (c).
2 is rotated by a distance of 4 and the state shown in FIGS. 2B and 2C is reached, and the protrusion 44b of the key-like piece 44 of the ring-shaped hole expanding bit 40 is disengaged from the recessed portion 31b of the center bit 30.
When the inner pipe 20 is pulled up as it is, the ring-shaped hole-expanding bit 40 is left at the hole butt, and the inner pipe 20 and the center bit 30 are pulled up.

[0021]

According to the present invention described in detail above, the following effects can be obtained. (1) Since the outer pipe is not subject to rotation or impact, it has the strength of steel pipes as in the past, but it does not require expensive pipes and can be made of vinyl chloride pipes, so it is cheap.

(2) If the ring-shaped hole-expanding bit has an inexpensive structure, the center bit is merely pressed against the hole butt and reversed, so that the bit diameter does not decrease unlike the conventional over-burten bit or retract bit. There is no fear.

(3) Unlike the double pipe bit, the bit attached to the outer pipe does not drill, so that the drilling speed does not decrease even on hard rock ground.

[Brief description of the drawings]

FIG. 1 is a view showing a state where a ring-shaped hole-expanding bit is engaged with a center bit according to an embodiment of the present invention, (a) is a plan view, and (b) is a view taken along the line BB of (a). Figure, (c) is (b)
6 is a cross-sectional view taken along the line CC of FIG. 6A, and FIG. 9D is a cross-sectional view taken along the line AOA of FIG.

FIG. 2 is a view showing a state in which the center bit and the ring-shaped hole-expanding bit are disengaged from each other according to the embodiment of the present invention;
Is a plan view, (b) is a sectional view taken along the line DD of (a), and (c) is a sectional view taken along the line EE of (b).

[Explanation of symbols]

 10 Outer Tube 20 Inner Tube 30 Center Bit 31 Strike Ring 31a Notch 31b Recessed Notch 32 Bit Part 32a Water Hole 33 Through Hole 40 Ring-shaped Expanded Bit 41 Through Hole 43 Rolling Discharge Section 44 Key Piece 44a Extending Part 44b protrusion 45 lower surface

Claims (2)

[Claims] 1. An outer tube, and a through hole having a diameter slightly larger than the outer diameter of the outer tube, the through hole being bored in the axial center, and the powder discharge section on a plurality of grooves on the outer periphery and extending downward from this. A ring-shaped hole-expanding bit having a key-shaped piece with a U-shaped cross-section and one end of which extends in the circumferential direction to form a protrusion, and the base end of which is connected to the inner pipe, and the bit portion of the tip has the ring shape. A center bit provided with a striking ring having a plurality of notches protruding from the through hole of the expanded hole bit and through which the extending portion of the key-shaped piece passes, and the ring-shaped expanded hole. The lower surface of the ring of the bit contacts the tip of the outer pipe, the extending portion of the key-like piece passes through the notch of the striking ring in the outer pipe, and the projection is detachably engaged with the recess of the striking ring. A casing digging bit characterized by being stopped. 2. The casing according to claim 1, wherein the center bit has a through hole and a plurality of water holes communicating with the through hole from the outer periphery near the tip of the bit portion in the axial center. Dig bit.