JP3952266B2 - Double pipe drilling tools - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double-pipe excavation tool, and more particularly, to a double-pipe excavation tool for installing a steel pipe when earth retaining is performed by a pipe roof construction method or a long tip receiving method.
[0002]
[Prior art]
In tunnel excavation and the like, it is known to implement a long tip receiving method or a pipe roof method, which is an example of a soil retaining method, in order to prevent collapse of a weak ground in front and above the face.
In these methods, a plurality of holes are opened toward the diagonally upper part of the weak ground in front of the face, and a steel pipe such as an injection pipe with a porous surface is inserted into each hole, and a solidifying agent is placed in the steel pipe. By injecting, the solidification agent is infiltrated into the surrounding ground from the porosity formed on the surface of the steel pipe to reinforce the weak ground planned to be excavated. Yes.
As a method for arranging the steel pipes in the ground, a known double-pipe excavation tool for drilling the ground, bedrock or the like as shown in FIG. 8 is used.
This tool has a ring bit c attached to the tip of an outer tube a arranged in the ground via a top joint b, an inner bit e attached to the tip of an inner tube d arranged in the outer tube a, Excavation is performed by transmitting the rotational force and striking force of d to the inner bit e and the ring bit c.
After excavating to a predetermined depth, the inner pipe d is pulled out together with the inner bit e, and the ring bit c, the top joint b, and the outer pipe d are left in the ground.
Here, the striking force of the inner tube d is transmitted to the outer tube a by the striking surface e2 of the striking member e1 of the inner bit e striking the receiving surface b1 of the top joint b.
Due to this striking force, a propulsive force to the ground of the outer tube a continuous rearward is generated.
[0003]
[Problems to be solved by the invention]
However, the conventional method has the following problems.
<A> Since the engagement surface of the inner bit and the ring bit is uneven engagement due to a level difference, the striking area is small and the engagement surface is easily worn by the striking force, and the striking force and rotational force of the inner bit is a ring. May not be transmitted to the bit.
<B> Since the excavating tool incorporates a striking member e1 that protrudes outward from the outer periphery of the inner bit e, the tool diameter is increased.
Therefore, the use is limited such that a small diameter steel pipe cannot be used as an outer pipe.
[0004]
OBJECT OF THE INVENTION
The present invention has been made to solve the above problems, and an object of the present invention is to provide a double-pipe excavation tool that reliably transmits the striking force and rotational force of the inner bit to the ring bit. To do.
Another object of the present invention is to provide a compact double-pipe excavation tool.
The present invention is intended to achieve at least one of the above objects.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the double-pipe excavation tool of the present invention is provided with a drilling means at the tip of the inner and outer double pipes to perform excavation by the rotational force and impact force of the inner pipe, In a double-pipe excavation tool configured to transmit force to the outer pipe side ,
An inner bit that is attached to the tip of the inner tube and transmits the rotational force and striking force of the inner tube ;
Having an inner portion engaging surface provided on the outer peripheral surface of the inner bit, and mounted around the outer peripheral surface of the inner bit, and a ring portion engaging surface for rotating together engaged with the inner portion engaging surface With a ring bit ,
A top joint through which the outer pipe is connected and the inner bit is inserted;
A locking portion interposed between the ring bit and the top joint ,
The locking portion has a female screw formed near the rear of the inner peripheral surface of the ring bit, a large diameter portion formed in front of the female screw, and a male screw formed near the front of the outer peripheral surface of the top joint. And a small-diameter portion formed behind the male screw,
After the male screw and the female screw are screwed together, the outer pipe is inserted through the top joint by the ring bit with the male screw entering the large diameter portion and the female screw entering the small diameter portion. It is characterized by being towed.
[0006]
Further, the double-pipe excavation tool of the present invention is characterized in that the inner portion engaging surface and the ring portion engaging surface are formed as tapered surfaces that are in surface contact with each other.
[0007]
Further , a male screw is formed at the rear end portion of the outer peripheral surface of the inner bit, and a female screw that is screwed to the male screw is formed at the tip portion of the inner peripheral surface of the outer tube,
An elastic material is inserted into a fitting gap formed when the male screw and the female screw are screwed together .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
<A> Double-pipe excavation tool As shown in FIG. 1, the double-pipe excavation tool 1 is constructed by providing excavation means 2 at the tips of the outer pipe 40 and the inner pipe 50, and the excavation means 2 provides a hole in the ground. The outer tube 40 is inserted into this hole while excavating the pipe.
The inner pipe 50 is for transmitting rotational force and striking force to the excavating means 2.
The excavating means 2 includes an inner bit 30 attached to the distal end portion of the inner pipe 50 and a ring bit 10 that is attached to and engaged with the outer peripheral surface of the inner bit 30.
The rotational force and striking force of the inner pipe 50 are transmitted to the inner bit 30, and the rotational force and striking force are also transmitted from the inner bit 30 to the ring bit 10.
The striking force transmitted to the ring bit 10 is transmitted to the outer tube 40 through the top joint 20 and gives a propulsive force to the outer tube 40.
[0012]
<B> Top Joint The top joint 20 is a pipe body having substantially the same diameter as the outer pipe 40, and the outer pipe 40 is connected to one end (rear side) by welding 7 or the like.
Further, a locking portion 4 that locks with the ring bit 10 is provided at the other end (front) of the top joint 20.
The locking portion 4 is for transmitting the striking force transmitted to the ring bit 10 to the top joint 20.
[0013]
For example, the locking portion 4 has a locking surface 21 protruding from the outer peripheral surface of the top joint 20, and a locking surface 13 protruding from the inner peripheral surface of the ring bit 10. The screws 22 and 14 are cut, the screws 22 and 14 are unscrewed, and the screw end surfaces 23 and 15 facing each other are brought into contact with each other.
When the screws 22 and 14 are formed on the locking surface 21 of the top joint 20 and the locking surface 13 of the ring bit 10, first the outer peripheral surface and the inner peripheral surface are cut deeper than the valleys of the screws 22 and 14 (see FIG. 5 (a)).
Since the screws 22 and 14 are formed at the cut-off portions, the screw end surfaces 23 and 15 become narrow and narrow threads, and the threads of the screw end surfaces 23 and 15 are crushed by the impact force (see FIG. 5B). ).
Since the screw end faces 23 and 15 are crushed, the screws 22 and 14 are not screwed together, so there is an advantage that the ring bit 10 and the top joint 20 are not likely to come off.
Although the hitting force from the ring bit 10 is transmitted to the top joint 20 by the engaging portion 4, the rotational force is not transmitted.
For this reason, the screw end surface 15 of the ring bit 10 forms an impact surface, and the screw end surface 23 of the top joint 20 forms an impact surface.
An inner bit 30 is inserted through the inner diameter portion of the top joint 20.
[0014]
<Ha> Ring Bit The ring bit 10 is provided with the excavation bit 17 at the tip, and is locked to the tip of the top joint 20 by the locking portion 4 described above at the rear end.
When the ring bit 10 is fitted to the top joint 20, the screws 14 and 22 are disengaged and the gap 4 a is generated, so that the ring bit 10 can be slid in the axial direction. The striking force can be effectively transmitted to the top joint 20.
Moreover, the ring part engaging surface 11 for engaging with the outer peripheral surface of the inner bit 30 mentioned later and rotating is provided in the inner peripheral surface of the ring bit 10.
[0015]
<D> Inner Bit The inner bit 30 is provided with a plurality of excavation bits 36 on the front end surface, and has a female threaded portion 33 on the other end side, and opens a water supply passage 34 communicating therewith on the front end surface.
A male screw portion 51 provided at the tip of the inner tube 50 is screwed into the female screw portion 33, and the inner bit 30 is attached to the tip of the inner tube 50.
The water supply path 52 of the inner pipe 50 and the water supply path 34 of the inner bit 30 communicate with each other, and drilling water is supplied through these water supply paths 52 and 34.
An inner portion engaging surface 31 that engages with the ring portion engaging surface 11 of the ring bit 10 protrudes from the outer peripheral surface of the inner bit 30, and the rotational force and striking force of the inner bit 30 are transmitted to the ring bit 10. To do.
[0016]
<E> Engagement surface The inner portion engagement surface 31 of the inner bit 30 includes three tapered surfaces protruding from the outer peripheral surface of the inner bit 30 (see FIGS. 2 and 3).
As can be seen from FIGS. 2 and 3, one of the side surfaces of the inner portion engaging surface 31 (the rotation direction of the inner bit 30) is scraped off by an arc to form the inner portion engaging side surface 32.
The ring portion engaging surface 11 of the ring bit 10 is three tapered surfaces provided on the inner peripheral surface of the ring bit 10.
One of the side surfaces of the ring portion engaging surface 11 forms a ring portion engaging side surface 12 that engages with the inner portion engaging side surface 32 of the inner bit 30.
By engaging the ring bit 10 around the inner bit 30, the engaging portion 5 in which the engaging surfaces 11 and 31 and the engaging side surfaces 12 and 32 are engaged is formed.
The striking force of the inner bit 30 is transmitted to the ring bit 10 by the engagement of the engaging surfaces 11 and 31.
The rotational force of the inner bit 30 is transmitted to the ring bit 10 by the engagement of the engagement side surfaces 12 and 32.
By forming the engagement surfaces 11 and 31 into tapered surfaces, the engagement area is increased, and the striking force of the inner bit 30 is reliably transmitted to the ring bit 10.
[0017]
<F> Outer tube The outer tube 40 is a tubular body such as a steel tube or a vinyl chloride tube that is placed in the ground, and is formed into an elongated cylindrical shape.
The outer pipe 40 is formed, for example, to have a length of about 3 meters and an outer diameter of about 80 mm, and constitutes a part of a support material that prevents collapse of the weak ground in front of or above the face during tunnel excavation, A part of drain pipe such as ground water is constructed.
The size of the outer tube 40 is a matter of design and can be appropriately selected according to the purpose of use.
Further, when the outer pipe 40 is used as a drain pipe such as ground water, or when cement milk, a chemical solution, mortar or the like is injected into the ground from the outer pipe 40, the outer pipe 40 has a hole on its outer peripheral surface. Use a perforated tube with a hole.
In the embodiment shown in FIG. 1, the outer tube 40 and the top joint 20 are connected by welding 7.
[0018]
The connecting portion between the outer tube 40 and the top joint 20 may be screwed with an elastic material 6 interposed as shown in FIG.
That is, the male screw part 24 provided on the outer peripheral surface of the top joint 20 with the connection part 3, the female screw part 41 of the outer tube 40 screwed to the male screw part 24, and the fitting gap between these screw parts 24, 41 are interposed. The elastic material 6 is used.
The screw portions 24 and 41 have a fitting gap of approximately one mountain when screwed together, and the elastic material 5 made of urethane rubber, natural rubber or the like is wound into the fitting gap and inserted into the coil gap.
When the striking force transmitted to the ring bit 10 is transmitted to the connecting portion 3 via the top joint 20, the male screw portion 24 of the top joint 20 transmits the striking force to the female screw portion 41 of the outer tube 40. Since the elastic material 6 is coiled and inserted into the entire fitting gap between 24 and 41, the elastic material 6 serves as a buffer member, and the screw portions 24 and 41 are not damaged, and the shaft that attenuates the impact force There is an effect of transmitting the directional force to the outer tube 40.
A male screw portion is provided on the outer peripheral surface of the outer tube 40, a female screw portion that is screwed to the male screw portion is provided in the top joint 20, and the elastic material 6 is wound in a coil shape into a fitting gap between the male screw portion and the female screw portion. The connecting portion 3 may be configured by insertion.
Further, the shock absorbing capacity of the elastic material 6 is set to such an extent that a striking force necessary for propelling the outer tube 40 into the ground can be secured.
[0019]
Since the double-pipe excavation tool 1 is thus configured, the rotational force and the striking force of the inner pipe 50 are transmitted to the ring bit 10 via the inner bit 30 and only the striking force is transmitted to the ring bit 10. Is transmitted to the outer tube 40 through the receiving surface (screw end surface 23) of the top joint 20 and the connecting portion 3 between the top joint 20 and the outer tube 40.
The excavated earth and sand is conveyed by the mud passage 8 formed by communicating the inner space of the top joint 20 from the front end surface of the inner bit 30 and the gap between the inner pipe 50 and the outer pipe 40, and the outer pipe. 40 is discharged from the rear end.
[0020]
[Action]
Next, a case where the outer pipe is inserted into the ground by the double pipe excavation tool of the present embodiment will be described.
[0021]
<A> Set of outer pipe The screw 14 of the ring bit 10 is screwed into the screw 22 of the top joint 20 to which the outer pipe 40 is connected.
As described above, the top joint 20 and the ring bit 10 are unscrewed from the screws 22 and 14 to form the locking portions 4 (screw end surfaces 23 and 15). It is mounted so that the impact force is transmitted but the rotational force is not transmitted.
[0022]
<B> The outer pipe is inserted and excavated by the inner bit 30 and the ring bit 10 by the rotational force and striking force of the inner pipe 50.
The striking force of the inner bit 30 is transmitted to the ring bit 10 by the engagement of the engagement surfaces 11 and 31 as described above.
The rotational force of the inner bit 30 is transmitted to the ring bit 10 by the engagement of the engagement side surfaces 12 and 32.
The striking force transmitted to the ring bit 10 is transmitted to the top joint 20, and a propulsive force is generated to insert the continuous outer tube 40 into the ground behind the top joint 20.
When a plurality of outer pipes 40 are connected and inserted deeply into the ground as in the case of use for drain pipes such as groundwater, connecting screws or the like are formed at both ends of the outer pipe 40.
Before the entire length of the outer tube 40 is inserted, the outer tube 40 to be inserted next is connected to the rear end of the outer tube 40.
In this way, the outer pipes 40, 40 are connected to each other and excavated to a predetermined depth, and the long and continuous outer pipes 40, 40 are arranged in the ground.
According to the present invention, since the inner bit 30 and the ring bit 10 are engaged by the engagement surfaces 11 and 31 and the engagement side surfaces 12 and 32 each having a tapered surface, the engagement area is increased, and the inner bit is increased. 30 striking force and rotational force can be reliably transmitted to the ring bit 10.
As described above, according to the present invention, because the taper engagement has a large striking area, the striking force of the ring bit 10 is large, and the outer tube 40 can be pulled by the ring bit 10.
Since there is no striking member that projects from the outer periphery of the inner bit as in the prior art, the portion that occupies the inner diameter portion of the tool 1 increases, and the engaging portion 5 that configures the tool 1 compactly or transmits rotational force and striking force. Can be greatly increased.
Moreover, since a small diameter steel pipe etc. can be used as an outer pipe, a use expands.
[0023]
Second Embodiment of the Invention
A locking surface 43 may be formed at the distal end (ring bit 10 side) of the outer tube 40 and locked with the locking surface 13 of the ring bit 10 (see FIG. 7).
As in the case of the top joint 10 described above, a screw 44 is cut on the locking surface 43 of the outer tube 40 to form a screw end surface 45.
The screw 14 of the ring bit 10 is screwed onto the screw 44, the screws 44, 14 are unscrewed, and the screw end surfaces 45, 15 that are opposed to each other are brought into contact with each other, whereby the locking portion 4 is configured.
Although the striking force from the ring bit 10 is transmitted to the outer tube 40 by the locking portion 4, the rotational force is not transmitted.
For this reason, the screw end surface 15 of the ring bit 10 forms an impact surface, and the screw end surface 45 of the outer tube 40 forms an impact surface.
In the case of this example, since the top joint 20 can be omitted, the cost can be reduced.
In the case of this example, since the ring bit 10 directly pulls the outer tube 40, the outer tube can be effectively inserted into the ground.
[0024]
【The invention's effect】
Since the present invention is as described above, the following effects can be obtained.
<A> Since the inner bit and the ring bit are engaged by the engagement surface and the engagement side surface formed of a tapered surface, the engagement area is increased, and the impact force and rotational force of the inner bit are reliably ensured. Can be communicated to.
<B> Due to the taper engagement with a large striking area, the striking force of the ring bit is large, and the outer pipe can be pulled by the ring bit.
<C> Since there is no striking member that protrudes from the outer periphery of the inner bit as in the conventional case, the portion that occupies the inner diameter of the double-pipe type drilling tool increases, and the double-pipe type drilling tool can be configured compactly or rotated. The engaging portion for transmitting the force and the striking force can be made large.
[Brief description of the drawings]
1 is a cross-sectional view of a double-pipe excavation tool according to an embodiment of the present invention. FIG. 2 is a front view of an inner bit. FIG. 3 is a side view of an inner bit. FIG. 4 is a cross-sectional view of a ring bit. FIG. 6 is a cross-sectional view showing another embodiment. FIG. 7 is a cross-sectional view showing another embodiment. FIG. 8 is an explanatory view of the prior art.
DESCRIPTION OF SYMBOLS 1 .... Double pipe type excavation tool 2 .... Drilling means 3 ... Connection part 4 ... Locking part 5 ... Engagement part 7 ... Welding 10 ... -Ring bit 11 ... Ring part engaging surface 12 ... Ring part engaging side surface 13 ... Locking surface 20 ... Top joint 21 ... Locking surface 30 ... Inner bit 31 ... Inner part engaging surface 32 ... Inner part engaging side surface 40 ... Outer tube 41 ... Female thread 50 ... Inner tube

Claims (3)

Drilling means at the distal end of the inner and outer double pipe provided, performs drilling by rotation force and striking force of the inner tube, the double-pipe drilling tool configured to be able to transmit the striking force of the inner tube to the outer tube side,
An inner bit that is attached to the tip of the inner tube and transmits the rotational force and striking force of the inner tube ;
Having an inner portion engaging surface provided on the outer peripheral surface of the inner bit, and mounted around the outer peripheral surface of the inner bit, and a ring portion engaging surface for rotating together engaged with the inner portion engaging surface With a ring bit ,
A top joint through which the outer pipe is connected and the inner bit is inserted;
A locking portion interposed between the ring bit and the top joint ,
The locking portion includes a female screw formed near the rear of the inner peripheral surface of the ring bit, a large diameter portion formed in front of the female screw, and a male screw formed near the front of the outer peripheral surface of the top joint. And a small-diameter portion formed behind the male screw,
After the male screw and the female screw are screwed together, the outer tube is inserted through the top joint by the ring bit with the male screw entering the large-diameter portion and the female screw entering the small-diameter portion. A double-pipe excavation tool characterized by being towed.   2. The double-pipe excavation tool according to claim 1, wherein the inner portion engagement surface and the ring portion engagement surface are formed as tapered surfaces that are in surface contact with each other. A male screw is formed at the rear end portion of the outer peripheral surface of the inner bit, and a female screw that is screwed to the male screw is formed at the tip portion of the inner peripheral surface of the outer tube,
The double-pipe excavation tool according to claim 1 or 2, wherein an elastic material is inserted into a fitting gap formed when the male screw and the female screw are screwed together .

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