JPH02308088A - Drill device - Google Patents

Abstract

PURPOSE:To prevent the falling-down of bit when a rod is pulled out by a method in which a sleeve to connect a preceding bit and an expandible(diameter) wing bit to a rod stem is pin-connected with the rod stem in an axially sliding manner. CONSTITUTION:A preceding bit 17 and an expandible(diameter) wing bit 21 are connected to a rod stem a sleeve 13. The rod stem 12 has a notch 26 in the axial direction and a gently sloped face on its end 26a. The sleeve 13 has a pin hole 29 through which a pin 28 is inserted to connect the sleeve 13 with the rod stem 12 in a sliding manner. During drilling work, the diameter of the bit 21 is expanded, and when the rod 6 is pulled out, the diameter of the bit 21 is contracted. The falling-down of the bit during the pull-out period of the rod 6 can thus be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drilling device used for driving reinforcing steel pipes into the ground after excavation during tunnel excavation using the NATM method or the like.

[Prior art 1] A tunnel construction in which a steel pipe having a plurality of holes in one circumferential wall is driven into the ground to reinforce the outer circumference of the tunnel after excavation, and a fixing material is injected into the ground through the holes of the steel pipe. There is a drilling method. Conventionally, a hole for inserting a steel pipe was drilled in advance, and then the steel pipe was separately inserted into the hole, but this method was inefficient because drilling the hole and inserting the steel pipe were performed separately, and the diameter of the hole to be drilled was too small. There were problems such as the inner wall of the hole would collapse immediately, making it difficult to insert the steel pipe.

In order to solve this problem, for example, as shown in FIG. (Second bit) 21', 21', and a wing bit 21 is provided in the drilling part as shown in Figure (a).
', 21' are extended outward to drill a hole, and at the same time, a steel pipe 10 attached to the outer periphery of the drilling rod 6' is inserted into the ground. This hole-drilling device is constructed so that the bits 21' and 21' are immersed in the sleeve 13' to reduce the diameter, and the drilling rod 6' is pulled out leaving only the steel pipe 10, and allows drilling and insertion of the steel pipe at the same time. A device has been proposed (#gansho 62
-112594).

[Problems to be Solved by the Invention] However, in the conventional drilling device described above, when the drilling rod is pulled out together with the preceding bit and the wing bit at the end of drilling, a member such as a hook plate 30 provided on the front side of the wing bit is removed. This was designed to prevent the wing bit from coming loose, but these parts were damaged due to the large impact force applied.

There was a risk that smooth extraction would not be possible.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration.

That is, the drilling device according to the present invention has a drilling rod attached to the rock drilling machine body, and a rod stem provided at the tip of the drilling rod, which is slidable in the axial direction and is not mutually rotatable. The rod stem includes a sleeve to be fitted, a leading bit attached to the front end of the sleeve, and a wing bit held so as to be expandable and contractable in the radial direction by the sleeve behind the leading bit, and the sleeve fits into the rod stem. A notch of a predetermined length is provided in the sleeve, and a pin hole is provided in the sleeve facing the notch in a direction perpendicular to the axial direction, and a part of the outer circumference is engaged with the notch in the pin hole. It is characterized by having a matching pin inserted through it.

[Function 1: A notch is provided in the sleeve fitting part of the rod stem provided at the tip of the drilling rod, and a pin inserted into the pin hole of the sleeve in a direction perpendicular to the shaft engages with this notch. Therefore, the sleeve holding the wing bit can move back and forth by a predetermined length, and is prevented from coming off by the pin.

[Example] Hereinafter, the example shown in FIGS. 1 to 4 will be described.

This drilling device t has an intermediate rod 6 connected to a shank rod 3 attached to a rock drill body 2 by a rod sleeve 5.
are joined, and a drilling portion 7 is provided at the tip of the intermediate rod. Further, a steel pipe 10 is held in a cylindrical pipe holder 9 attached to the bases of the shank rod 3 and the intermediate rod 6, and the front end of the steel pipe reaches immediately after the drilling part 7.

FIGS. 2(a) and 2(b) are cross-sectional views of the hail hole drilling section 7 in different states, and the drilling rod is constructed by screwing a rod stem 12 onto the tip of the intermediate rod 6. A sleeve 13 is fitted to the outer circumference of a sleeve fitting fi12a formed in a hexagonal cross section of the rod stem so as to be slidable in the axial direction and not to rotate with respect to the other. A mounting screw 1'5 is threaded into the front end of the sleeve 13, and a plurality of spherical blades 16. Leading bit 1 with...
7 is attached to this mounting screw 15. In addition, a pair of wing bit accommodating parts 19,19 consisting of groove-shaped notches in the axial direction are formed in the intermediate part of the sleeve 13, and a wing bit accommodating part 19,19 having a spherical blade 20 at the outer end is formed in this accommodating part. 21.21 is accommodated.

The wing pit 21 is formed in such a shape that a rear inner surface 21a is hollowed out, and the inner surface of the portion in front of this is a projecting surface 21b that projects inward. Further, a protrusion 23 that protrudes diagonally inward is provided at the front end, and a base 24 that fits into the dish-shaped recess 13a of the sleeve 13 is provided at the rear end.
is provided. As shown in FIG. 4, the protrusions 23.23 on the front side of the wing bits 21, 21 have a thickness of about half of the entire wing bit 21, and are provided offset to the left or right side. 21 into the housing part 1
9.19 When the bits are immersed, the protruding parts 23 of both bits
．． 23 are arranged to overlap in the thickness direction. Therefore, even if the protrusion 23 is provided, the wing bit 21
In addition, when the diameter of the wing bit is large or when the amount of extrusion of the wing bit is small, it is not necessary to overlap the protrusions in this way.

On the other hand, at the front end of the rod stem 12, a tongue-shaped guide protrusion 25 is provided toward the front, the top and bottom surfaces of which are tapered to correspond to the protrusion 23 of the wing bit. Furthermore, an elongated notch 26 is provided behind the guide protrusion 25 .

Further, a pin hole 29 is provided in the inner surface of the sleeve 13 so as to face the notch 26 . The pin hole 29 is formed in a direction perpendicular to the axial direction (orthogonal in the illustrated example), and a part of the inner circumferential surface is missing and opens toward the notch 26 . A pin 28 is inserted through the pin hole 29, and a portion of the outer peripheral surface of the pin is exposed and engaged with the notch 26.

Therefore, the sleeve 13 can move relative to the rod stem 12 by the length of the notch 26, but the sleeve 13 will not separate from the rod stem 12 unless the pin 28 is removed. The end portion 2'6a has a gentle slope.

It is designed to absorb impact energy well.

When drilling a hole, a steel pipe 10 is loosely fitted around the outer periphery of the intermediate rod 6, held by the pipe holder 9, and the rock drill body 2 is operated to press the hole portion 7 against the surface of the earth. At this time, water or air is discharged forward through the water holes 6a and 17a. A relatively small diameter hole is drilled by the leading pin 17, and then this hole is enlarged to a diameter greater than the outer diameter of the steel pipe 10 by the wing bit 21, 21 in its enlarged state. The diameter expansion of the wing bit 21.21 (7) is carried out by the rod stem 12 moving forward relative to this, and the guide protrusion 25 of the rod stem moves forward and comes into contact with the protrusion 23.23, This is done by pushing these up and down to spread them apart. At this time, the single wing bit 21.21 is fixed at the drilling position shown in FIG. 2(a). Further, the base 24 of the wing bit comes into contact with the end surface of the dish-shaped recess 13a of the sleeve 13, and the thrust and impact force of the drilling rod are transmitted, and the protruding surface 21b on the inside of the front part of the wing bit 21 contacts the end surface of the dish-shaped recess 13a of the sleeve 13. 1
2 and resists external force in the direction of diameter reduction. In addition,
Movement of the wing bit 21.21 in the centrifugal direction is restrained by a ring 22 that fits into the sleeve 13 on the back side of the leading bit 17 and a dish-shaped recess 13a of the sleeve.

When drilling is completed and the drilling rod is retracted.

The rod stem 12 moves relative to the sleeve 13 and the wing bit 21.21, the projecting surface 21b is no longer in contact with the outer surface of the rod stem 12, and the guide projection 25 is retracted behind the projection 23.23. For this reason,
There is no longer anything to resist the movement of the wing bit 21° 21 in the direction of diameter reduction.

The wing bit 21.21 sinks into the receptacle 19.19 when pushed inward, such as by the end of the steel pipe 10. In this way, since the wing bit 21.21 is in a reduced diameter state where it is recessed into the accommodation portion 19.19 of the sleeve 13, if the steel pipe 10 is removed from the pipe holder 9, the preceding bit 17° and the wing bit 21 ,21. The rod stem 12, sleeve 13, etc. can be pulled out to the outside through the inside of the steel pipe IO. That is, first, a small-diameter pilot hole is drilled with a leading bit 17 having a smaller diameter than the outer diameter of the steel pipe 10;
Continue using the wing bit 21.2 with a diameter larger than the outside diameter of the steel pipe.
In step 1, the pilot hole is expanded.During this step, a steel pipe 10 for burial is also inserted into the hole, and once the hole has been drilled to a predetermined depth,
The steel pipe 10 is removed from the pipe holder 9 and left in the drilled hole, and the leading bit, wing bit, drilling rod, etc. are pulled out through the inside of the steel pipe 10 to the outside.

A fixing material is injected into the remaining steel pipe.

In this drilling device, the guide protrusion 25 provided at the tip of the drilling rod presses the inward protrusion of the wing bit 21.21 outward from the inside to enlarge the diameter of the wing bit. The expansion/contraction operation is reliable and the strength is excellent. Moreover, since the sleeve 13 and the rod stem 12 are slidably engaged by the pins 28 that intersect in the axial direction, separation of the two is prevented. In addition, contrary to the illustrated example, the pin may be provided on the rod stem side and the notch portion may be formed on the sleeve side.

[Effects of the Invention] As explained above, in the drilling device according to the present invention, the sleeve for holding the bead and the rod stem provided at the tip of the drilling rod are aligned in a direction intersecting the axial direction. Since the inserted pin and the notch of a predetermined length in which the pin is slidably engaged are connected to be movable relative to each other, the bit does not come off when the drilling rod is pulled out.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing the state of use of a drilling device which is an embodiment of the present invention, Fig. 2(a) is a sectional view of the drilling part in the drilling part, and Fig. 2(b) is a drawing 3 is a sectional view taken along line A-A in FIG. 2(a), FIG. 4 is a sectional view taken along line B-B in FIG. 2(b), and FIG. 5(a). (b) is a sectional view of a conventional drilling device. l...Drilling device, 2...Drilling rock, 3...Shank rod, 6...Intermediate rod, 7...Drilling part,
lO...Steel pipe, 12...Rod stem, 13...
Sleeve, 17... Leading bit, 19... Wing bit accommodating portion, 21... Wing bit, 23...
Projection part, 25... Guide protrusion, 26... Notch part, 2
8...Pin.

Claims (1)

[Claims] (1) A drilling rod attached to the rock drilling machine body,
a sleeve that is slidable in the axial direction and is fitted to the outer periphery of the rod stem provided at the tip of the drilling rod, and that is non-rotatable with respect to the other; a leading bit that is attached to the front end of the sleeve;
a wing bit held by the sleeve so as to be expandable and retractable in the radial direction behind the leading bit; a notch of a predetermined length is provided in the sleeve fitting portion of the rod stem; A drilling device characterized in that a pin hole is provided in a direction perpendicular to the axial direction so as to face the hole, and a pin is inserted into the pin hole so that a part of the outer circumference engages with the notch.