JPH0771181A - Boring device - Google Patents

Abstract

PURPOSE:To facilitate processing, suppress wear, and prolong lifetime by fitting a head system to be provided on a boring rod in a head sleeve to hold a bit with the aid of a key or spline, and restraining the idle rotation. CONSTITUTION:The boring rod 6 of a rock boring machine is fitted at the tip with a head stem 12. and a head sleeve 13 is fitted on the head stem 12 in such a way as slidable in axial direction and incapable of relative rotating. A preceding bit 17 is fited on the foremost extremity of this head sleeve 13, and a wing bit 21 is provided which is held with possibility of diametric enlargement and shrinkage. At the time of boring, the wing bit 21 is overhung outermore than the periphery of the preceding bit 17, and is set innermore than the bit periphery when the boring rod 6 is retreated. Therein the head stem 12 and head sleeve 13 are restrained so as not to rotate relatively with an axially stretching key 32 or spline in confronting the outside surface of the stem 12 and the inside surface of the sleeve 13. This enables the fit part 12a to be formed equipped with a circular section, and rattles of the fit part 12a can be lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for driving a steel pipe into soft ground to improve the ground and for driving a steel pipe for reinforcement into the ground after excavation in tunnel excavation by the NATM method or the like. The present invention relates to a drilling device.

[0002]

2. Description of the Related Art Conventionally, in order to reinforce the outer peripheral portion of a tunnel after excavation, a hole for inserting a steel bar is previously drilled, a fixing agent is injected into the hole, and then a steel bar is separately inserted. . In this method, the drilling and fixing agent injection and the steel bar insertion are performed separately, so the work efficiency is poor, and the inner wall of the hole collapses during drilling or immediately after drilling, and the fixing agent injection or steel bar insertion is not possible. There were problems such as difficulty.

In order to solve this, for example, as shown in FIG. 15, a leading bit (first bit) 54 provided on the front surface of the hole and a wing provided behind the leading bit. Bit (second bit) 55, 55
When drilling, the wing bits 55, 55 are projected outward to perform the drilling, and at the same time, the drilling rod 5
Insert the steel pipe 53 mounted on the outer periphery of 7 into the ground, and after finishing drilling, attach the wing bits 55, 55 to the head sleeve 5
A drilling device has been proposed in which the drilling rod 57 can be inserted at the same time by immersing it in the slit 13 of No. 9 to reduce its diameter and pulling out the drilling rod 57 leaving only the steel pipe 53 (Patent application 62-112594). In this device, the fitting portion of the head sleeve 59 and the head stem 60 is formed in a hexagonal cross section, and the head sleeve 5
9 and the head stem 60 are fitted so as to be slidable in the axial direction and non-rotatable.

[0004]

However, the drilling device having the above-mentioned structure does not cause any trouble when the ground to be drilled is relatively soft such as a sand layer or a clay layer, but the gravel layer, the boulder layer, and the bedrock. When the strength is high, such as, the rotational resistance transmitted to the wing bit, the head sleeve, and the head stem becomes large, and the impact on the hexagonal ridge portion of the head stem also becomes large, so that this portion was easily worn. Particularly, a fitting portion having a hexagonal cross section has rattling from the beginning in terms of processing accuracy, and the hexagonal ridge portion is easily worn.

As described above, when the hexagonal ridge portion of the fitting portion is worn, a positional deviation occurs in the rotational direction between the head stem and the head sleeve, so that the wing bit is twisted and the wing bit is damaged early. There was a problem of doing.

[0006]

In order to solve the above problems, the present invention has the following constitution. That is, the drilling device according to the present invention comprises a head sleeve fitted axially slidably and non-rotatably to the outer periphery of the head stem at the tip of the drilling rod attached to the drilling machine body, and the head sleeve. A wing bit that is mounted on the front end of the wing, and a wing bit that is held so as to be expandable and contractible in the radial direction with the rear side of the groove-shaped recess serving as the wing bit accommodating portion formed in the head sleeve as a base point In the drilling device, wherein the bit is extended outwardly from the outer diameter of the preceding bit when drilling, and is retracted inward from the outer diameter of the preceding bit when the drilling rod is retracted, The head stem and head sleeve
By a key or spline along the axial direction provided at the opposing portion of the head stem outer peripheral surface and the head sleeve inner peripheral surface,
It is characterized by being constrained so that they cannot rotate relative to each other.

[0007]

The mutual rotation between the head sleeve holding the wing bit and the head stem connected to the drilled rod is constrained by a key or spline, so that the fitting portion of both is formed in a circular cross section. Therefore, it is possible to reduce the amount of backlash in the fitting portion while facilitating the processing.

[0008]

EXAMPLES The examples shown in FIGS. 1 to 5 will be described below. This drilling device 1 comprises a drilling machine body 2
The intermediate rod (drilling rod) 6 is joined by the coupling sleeve 5 to the shank rod 3 attached to the
A hole portion 7 is provided at the tip of each of these hole rods. Further, the steel pipe 10 is held by the tubular pipe holder 9 mounted on the bases of the shank rod 3 and the intermediate rod 6,
The front end portion of the steel pipe reaches the portion immediately after the punched hole portion 7.

FIGS. 2 and 3 are sectional views of a hole portion 7 showing different states of the first embodiment using a key, in which the head stem 1 is provided at the tip portion of the intermediate rod 6.
2, a head sleeve 13 having a circular cross section is fitted to an outer peripheral portion of a head sleeve fitting portion 12a having a circular cross section of the head stem so as to be axially slidable and non-rotatable. A mounting screw 15 is threaded on the front end of the head sleeve 13, and a leading bit having a plurality of sharp cemented carbide blades (may be blades of other shapes) 16, ... 17 is attached to the mounting screw 15. Further, in the middle portion of the head sleeve 13, four wing bit accommodating portions 19, which are groove-shaped notches in the axial direction, ...
The wing bit 21 having the blade body 20 at the outer end is housed in the housing. The wing bit 21 is formed in a shape in which a rear inner surface 21a is scooped out, and an inner surface of a portion in front of the wing bit 21 is a protruding surface 21b protruding inward. Further, a projecting portion 23 is provided obliquely inward at the front end portion, and a projecting portion 22 and a step portion 24 for preventing coming off are provided at the rear end portion. The projection 23 on the front side of the wing bit 21 has a thickness of the wing bit 21.
About half of the whole, inclined surfaces of each α (about 90 degrees) are formed so as to be pointed inward. When the four wing bits 21 arranged at equal intervals around the axis are immersed in the accommodating portion 19, the protruding portions 23 of the four bits are adjacent to each other with a slight gap. It has become. Therefore, even if the protrusion 23 is provided, it does not interfere with the accommodation (reduction) of the wing bit 21. In addition, when the diameter of the wing bit is large or when the pushing amount 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 portion of the head stem 12, a tongue-shaped guide projection 25 is formed which projects toward the front corresponding to the projection portion 23 of the wing bit and whose upper and lower surfaces on the tip side are tapered. ing. Furthermore, this guide protrusion 2
The cutout portion 26 with which the step portion 24 is engaged is provided behind 5
Is provided.

Further, on the circular inner surface of the head sleeve 13, there are provided four key mounting grooves 30, ... Penetrating inward and outward at intervals between the wing bits 21, ... Has been. Further, the head stem 12 having a circular cross section is provided with key grooves 31, ... at positions facing the key mounting grooves 30, ... on the head sleeve side. A key 32 having a flange portion 32a is fitted in the key mounting groove 30, ... On the side of the head sleeve, and this key is slidably fitted in the key groove 31 of the head stem 12. There is. The relative rotation between the head sleeve 13 and the head stem 12 is restricted by these four keys. Supports 33, ... Which prevent the eccentricity of the steel pipe 10 are attached to the outer peripheral portion of the head sleeve 13.

At the time of drilling, the steel pipe 10 is loosely fitted to the outer peripheral portion of the intermediate rod 6 and held by the pipe holder 9, and the drilling machine main body 2 is operated, while the drilling portion 7 is grounded. Press on the surface. At this time, water or air is discharged forward through the water holes 6a and 17a. Leading bit 17
A relatively small diameter hole is drilled by the wing bit 21, ...
The diameter is larger than the outer diameter of. Wing bit 21,
The expansion of the diameter of the head stem 12 is performed by moving the head stem 12 forward relative to the head stem 12, and the guide protrusion 25 of the head stem moves forward to contact the protrusion 23, and pushes it upward and downward. Done. At this time, the wing bits 21, ... Are fixed at the drilling hole positions shown in FIG. Further, the step portion 24 contacts the rear end portion of the accommodating portion 19, the thrust force and the striking force of the drilling rod are transmitted, and the projecting surface 21b inside the front portion of the wing bit 21 contacts the outer surface of the head stem 12. Contact with each other to counteract the external force in the radial direction. The movement of the wing bits 21, ... In the centrifugal direction is restricted by the ring 35 fitted to the head sleeve 13 and the head sleeve on the back side of the preceding bit 17.

The rotational force transmitted from the punched rod 6 to the head stem 12 is transmitted to the head sleeve 13 via the keys 32, ..., And the leading bit 17 and the wing bit 2
Rotate 1.

When the drilling rod is retracted after the drilling is completed, the head stem 12 moves relative to the head sleeve 13 and the wing bits 21 ,.
Does not come into contact with the outer surface of the head stem 12, and the guide protrusion 25 is retracted rearward of the protrusions 23, 23.
For this reason, there is nothing that resists the movement of the wing bits 21, ... In the diameter reducing direction, and when the wing bits 21, ... Are pushed inward by the end portion or the like of the steel pipe 10, as shown in FIGS. Immerse in the storage unit 19, .... In this state, the leading bit 17, the wing bit 21, ..., The head stem 12, the head sleeve 13 and the like can be pulled out rearward through the inside of the steel pipe 10. That is, the pilot bit 17 having a smaller diameter than the outer diameter of the steel pipe 10 is first used to drill a small-diameter pilot hole, and subsequently the wing bit 21, which has a larger diameter than the outer diameter of the steel pipe, is used to open the pilot hole. During this time, the steel pipe 10 for burying is inserted into the hole together and when the drilling of a predetermined depth is completed, the steel pipe 10 is removed from the pipe holder 9 and left in the drilled hole, and the preceding bit, wing bit, The punch rod or the like is pulled out through the inside of the steel pipe 10. The fixing material is injected into the remaining steel pipe.

In this punching device, the guide projection 25 provided at the tip of the head stem pushes the inward projections of the wing bits 21, ... Therefore, the expansion / contraction operation is reliable and the strength is excellent. Further, since the fitting portion of the head stem and the head sleeve is formed to have a circular cross section, it is easy to improve the working accuracy of the working portion and reduce the rattling, and the life of the wing bit etc. can be greatly extended. Can be improved. As a result of the actual drilling test, the wing bit life of the conventional product was 200 to 300 m for the sand and clay layers, whereas it was 300 to 350 m for the product of the present invention. Also,
For the rubble and boulder layers, the conventional product had a length of 20 to 30 m, whereas the product of the present invention had a thickness of about 200 m.

Next, FIGS. 9 to 14 show an embodiment different from the above. In this embodiment, the mutual rotation of the head stem and the head sleeve is restrained by a spline instead of the key. That is, the head stem 4
2 is provided with a spline 45, and a head sleeve 43 is provided with a spline groove 46. Due to the fitting of the spline and the spline groove, the rotation of the drilling rod is transmitted to the preceding bit 17 and the wing bits 21, ... Through the head stem 42 and the head sleeve 43. Other parts are the same as in the above-mentioned embodiment.

[0017]

As described above, in the drilling device according to the present invention, the head stem attached to the drilling rod and the head sleeve holding the preceding bit and the wing bit are provided via the key or the spline. Since it fits and restrains idling, it is possible to form the fitting part of both with a circular cross section, easy to process, less wear due to rattling, and improving the life of wing bits etc. Is now possible.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a usage state of a punching device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a punched portion during punching.

FIG. 3 is a cross-sectional view of a drill hole portion at the time of pulling out.

4 is a sectional view taken along line AA in FIG.

5 is a sectional view taken along line BB in FIG.

FIG. 6 is a side view of a wing bit.

FIG. 7 is a plan view of a wing bit.

FIG. 8 is a front view of a wing bit.

FIG. 9 is a cross-sectional view of another embodiment when punching.

FIG. 10 is a cross-sectional view at the time of extraction.

11 is a cross-sectional view taken along line CC of FIG.

12 is a cross-sectional view taken along line DD in FIG.

FIG. 13 is a vertical sectional view of a head stem.

14 is a cross-sectional view taken along line EE in FIG.

FIG. 15 is a cross-sectional view of a conventional device.

[Explanation of symbols]

 1 Drilling device 2 Drilling machine 3 Shank rod 6 Intermediate rod 7 Drilling part 10 Steel pipe 12 Head stem 13 Head sleeve 17 Leading bit 19 Wing bit accommodating part 21 Wing bit 23 Protruding part 25 Guide protrusion 32 Key 45 Spline

Claims (1)

[Claims] 1. A head sleeve fitted to the outer periphery of a head stem at the tip of a drilling rod attached to a rock drill main body, the head sleeve being fitted axially slidably and non-rotatably, and mounted on the front end of the head sleeve. A leading bit and a wing bit that is held so as to be expandable and contractible in the radial direction with the rear side of the groove-shaped recess serving as the wing bit accommodating portion formed in the head sleeve serving as a base point,
In a drilling device configured to be projected outward from the outer diameter of the preceding bit during drilling, and to be drawn inward from the outer diameter of the preceding bit when the drilling rod is retracted, the head stem and A punching device, wherein the head sleeve and a head stem outer peripheral surface and a head sleeve inner peripheral surface are mutually non-rotatably restrained by a key or a spline provided in an opposed portion along the axial direction.