JP2003239672A - Cleaning swivel for rotary percussion double-pipe excavator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning swivel for use in a double-pipe excavating method employing a down-the-hole hammer, which can solve various problems. <P>SOLUTION: The cleaning swivel is formed of a top sub 2, an outer rod sub 3, an inner rod sub 4, and a swivel case 5. The top sub 2 is connected to a drill head and has an air channel 9 formed therein. The outer rod sub 3 is fixed to the top sub 2 and has a hydraulic cylinder chamber 15 formed therein at a location between its annular diaphragm portion 14 and the top sub 2. The inner rod sub 4 is inserted into the outer rod sub 3, and has its rear end and its intermediate portion slidably fitted into the air channel 9 and the annular diaphragm portion 14, respectively. The inner rod sub 4 is provided with a piston 14. The swivel case 5 has splines 18, 19 for transmitting torque from the outer rod sub 3 to the inner rod sub 4, and an annular air chamber 23, annular liquid chambers 24a, 24b, and an annular cuttings chamber 25 which are located inside a peripheral surface thereof. The swivel case 5 also has an air inflow port 26, liquid outlet ports 27a, 27b, and a cuttings exhaust port 28 which are located on the peripheral surface thereof and communicate with the annular air chamber, the annular liquid chambers and the annular cuttings chamber, respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning swivel for a double pipe excavator, and more particularly to a swivel joint suitable when a down-the-hole hammer is used together with a rotary percussion drill.

[0002]

2. Description of the Related Art The double pipe excavation method using a rotary percussion drill having a hydraulic drill head is generally used as a method under geological conditions with collapsible property because it can excavate while protecting the hole wall with an outer pipe (outer rod). ing. However, this method also has the following weak points.

After excavating a collapsible formation, if it hits a stable hard rock layer or a hard boulder, the excavation speed will decrease. In addition, a lightweight and compact rotary percussion drill is difficult to obtain sufficient drilling efficiency due to insufficient power. As the digging depth increases, the impact force of the hydraulic drill head is attenuated on the way.

In order to compensate for such a weak point, a down-the-hole hammer is attached to the tip of the inner pipe (inner rod) to supplementarily generate a striking force. In this case, the striking force by the hydraulic drill head is used. Is transmitted to the body of Down the Hole via the inner rod,
The following problems occur.

Generally, down-the-hole hammers on the market do not assume that the main body is hit by the hydraulic percussion, and have a strength problem. There is also a method of increasing the wall thickness of the main body to obtain this strength, but for example, if the wall thickness is increased on the outer diameter side, the clearance with the inner diameter of the outer rod becomes smaller, which may interfere with the discharge of the cuttings, or It will be necessary to combine it with another larger outer rod. Further, if the wall thickness is increased on the inner diameter side, the piston that generates the striking force also needs to be downsized, and the excavation capacity is reduced. Further, the hammer bit is hit by both the hydraulic drill head and the down-the-hole hammer, and it is very difficult to predict what kind of influence the hits having different frequencies will have, and it is impossible to predict the impact.

Therefore, in general, when it becomes difficult to excavate a double pipe by hydraulic percussion, the outer rod is left as a casing and the lower layer is switched to single excavation using only the down the hole hammer, and hydraulic percussion is not operated. The method is adopted.
However, in this case, the following problems occur.

Since the cleaning swivel which receives the cuttings discharged through the clearance between the outer rod and the inner rod and discharges in any direction by the hose or the like cannot be used, scattering of the cuttings is unavoidable. Since the bit diameter of down the hole hammer needs to be smaller than the inner diameter of the outer rod, an outer rod / outer bit larger than one size is required to secure the designed finished hole diameter.

If there is a formation in the middle of a predetermined depth that is difficult to excavate by hydraulic percussion, and there is a formation below which the hole wall needs to be protected by an outer rod, after the core is once removed with a down the hole hammer, the outer rod
The outer bit must be expanded. However, in this case, it is difficult to discharge the cuttings unless the inner rod / inner bit is set again.If the cuttings cannot be set, there is a possibility that the outer bits will be prematurely worn or have seizures. Is high. Even when the inner rod / inner bit is reset, the inner rod will be in a state of impulsive impact unless the core hole diameter by down-the-hole hammer is sufficiently smaller than that of the inner bit, which may cause drilling accidents such as screw loosening and rod cutting. .

[0009]

The present invention has been made based on the above technical background, and achieves the following objects. An object of the present invention is to provide a cleaning swivel for a double pipe excavating device capable of solving various problems in a rotary percussion type double pipe excavating method that also uses a down-the-hole hammer.

[0010]

The present invention employs the following means in order to achieve the above object. That is, the present invention is a cleaning swivel that connects between a drill head that generates a rotational force and a striking force, and a double pipe consisting of an inner pipe and an outer pipe, the rear end of which is connected to the drill head. A top sub having an air flow path consisting of an axial portion opening to the front end and a radial portion opening to the outer circumference, and a rear end fixed to the outer circumference of the front end of the top sub, and an annular shape formed on the inner circumference of the middle portion thereof. An outer rod sub having a hydraulic cylinder chamber defined between the partition wall and the top sub, and an outer rod sub axially movably inserted into the outer rod sub, and a rear end portion of the outer rod sub in the axial direction of the air passage. In the portion, an intermediate portion is slidably fitted to the annular partition wall portion, and an inner rod sub provided with a piston capable of sliding in the hydraulic cylinder chamber on the outer periphery, and the outer rod sub to the inner rod sub. Means for transmitting a rotational force to the narod sub, and relatively rotatably fitted to the outer peripheries of the top sub and the outer rod sub, and having an annular air chamber, two front and rear annular liquid chambers, and an annular cutting chamber on the inner periphery. And a swivel case having an air inlet, two liquid inlets and outlets, and a cuttings outlet that communicate with the annular air chamber, the two annular liquid chambers, and the annular cuttings chamber, respectively. The annular air chamber communicates with a radial portion of the air flow path, and the two front and rear annular liquid chambers communicate with the front and rear chambers of the cylinder chamber through communication holes provided in the outer rod sub, respectively. The cutting chamber communicates with a space between the outer rod sub and the inner rod sub through a communication hole provided in the outer rod sub. In rotary percussion double pipe drilling apparatus for cleaning swivel characterized and.

More specifically, a small diameter portion is formed at the rear end portion of the inner rod sub, and the small diameter portion is slidably fitted to the axial portion of the air passage. Further, the means for transmitting the rotational force from the outer rod sub to the inner rod sub is a spline which is formed on the inner circumference of the outer rod sub and the outer circumference of the inner rod sub and is fitted to each other.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is an axial sectional view showing an embodiment of a cleaning swivel (swivel joint) according to the present invention, FIG. 2 is an enlarged sectional view taken along the line AA of FIG. 1, FIG. 3 is an exploded sectional view, and FIG. 4 is a cleaning swivel. It is sectional drawing which shows the state connected to the hydraulic drill head.
The cleaning swivel 1 according to the present invention includes a top sub 2, an outer rod sub 3, an inner rod sub 4, and a swivel case 5.

A female screw 8 is provided at the rear end of the top sub 2, and is connected to a hydraulic drill head 6 via a shank rod 7 connected to this female screw 8 (see FIG. 4). In addition, the top sub 2 has an axial portion 9 open at its front end.
An air flow path 9 is formed by a and a radial portion 9b that is open to the outer circumference. A step portion 10 is provided on the axial portion 9a.
Are formed.

The outer rod sub 3 has its rear end fixed to the outer periphery of the front end of the top sub 2 via a screw 11. An outer rod (not shown) is connected to the front end of the outer rod sub 3 via an outer rod coupling 12. The outer rod sub 3 is formed with an annular partition wall portion 14 on the inner periphery of the middle portion thereof.
The hydraulic cylinder chamber 15 is defined between the top sub 2 and the top sub 2.

The inner rod sub 4 is the outer rod sub 3
It is inserted movably in the axial direction. A female screw 16 for connecting an inner rod (not shown) is provided at the front end of the inner rod sub 4. The middle portion of the inner rod sub 4 is slidably fitted in the annular partition wall portion 14. A small diameter portion 13 is formed at the rear end portion of the inner rod sub 4, and the small diameter portion 13 is slidably fitted in the axial portion 9a of the air flow passage 9. Further, a piston 17 slidable in the hydraulic cylinder chamber 15 is provided on the outer periphery of the inner rod sub 4, and the hydraulic cylinder chamber 15 is divided into a front chamber 15a and a rear chamber 15b by the piston 17. From the above description, it is understood that the inner rod sub 4 having the piston 17 functions as a piston rod.

As shown in FIG. 2, a female spline 18 is provided on the inner periphery of the portion of the outer rod sub 3 which defines the hydraulic cylinder chamber 15. On the other hand, a male spline 19 that fits into the female spline 18 is provided on the outer periphery of the inner rod sub 4. The height of the male spline 19 is lower than the depth of the female spline 18, and as a result, the circumferential gap formed between these male and female splines 18, 19 is the front chamber 15a of the hydraulic cylinder chamber 15, Will be the passage.

The swivel case 5 is fitted on the outer peripheries of the top sub 2 and the outer rod sub 3 so as to be relatively rotatable. A retainer ring 21 for holding the swivel case on the top sub 2 and the outer rod sub 3 is fixed to the rear end of the swivel case 5 with screws 20. Further, the swivel case 5 is provided with a swivel stopper 22 for preventing co-rotation (see FIG. 4).

An annular air chamber 2 is provided on the inner circumference of the swivel case 5.
3, two front and rear annular oil chambers spaced from each other in the axial direction
4a, 24b and an annular cutting chamber 25 are provided respectively. Further, the swivel case 5 has an outer periphery which communicates with an air inlet 26 which communicates with the annular air chamber 23, two hydraulic oil inlets and outlets 27a and 27b which respectively communicate with the two annular oil chambers 24a and 24b, and an annular cutting chamber 25. A cuttings discharge port 28 is provided.

The annular air chamber 26 communicates with the radial portion 9b of the air passage 9. Further, the two annular oil chambers 24a, 24b communicate with the front and rear chambers 15a, 15b of the hydraulic cylinder chamber 15 via the communication holes 29a, 29b provided in the outer rod sub 3, respectively. Further, the annular cutting chamber 25 communicates with a space 31 between the outer rod sub 3 and the inner rod sub 4 through a communication hole 30 provided in the outer rod sub 3.

Next, the operation of the above embodiment will be described. FIG. 5 is an axial sectional view showing a state of excavating together with a down the hole hammer. At the time of excavation, the outer casing 3 is connected to the outer rod sub 3 and the first casing 34 having the outer rod coupling 12, the outer rod 32, and the outer bit 33. The inner rod sub 4 includes an inner rod 35 and a starting rod 3 that form an inner pipe.
6 are connected respectively. Further, a hammer bit 38 is attached to the starting rod 36 via an adapter sub 37.
The down-the-hole hammer 39 having is connected.

This down-the-hole hammer 39 is well known, and a detailed description thereof will be omitted. However, a piston for operating the compressed air to give a striking force to the hammer bit 38 is built-in, and when the hammer bit 38 is pressed against the bottom of the drill hole, the hammer bit 38 is hit. Is started (state of FIG. 5A). When the hammer bit 38 is separated from the bottom of the drill hole and the hammer bit 38 descends from the down-the-hole hammer body by a bit stroke S2, almost all of the compressed air is ejected from the tip of the hammer bit 38, and this ejected air causes the bottom of the drill hole to be ejected. The structure is such that the cuttings remaining in the surroundings can be effectively eliminated (flushing) (state of FIG. 5B).

In order to obtain the excavated state shown in FIG. 5 (a), hydraulic oil of a predetermined pressure is supplied from the hydraulic oil inlet / outlet 27b shown in FIG. 1 to the hydraulic cylinder rear chamber 15b through the annular oil chamber 24b and the communication hole 29b. Supply. As a result, the inner rod sub 4
Moves in the axial direction, and the hammer bit 38 of the down the hole hammer 39 projects from the first casing 34.
At this time, that is, when the inner rod sub 4 advances to the stroke end, the splines 18 and 19 mesh with each other in the maximum area, and this position becomes the standard excavation position.

At the time of excavation, the rotating force and the striking force generated by the hydraulic drill head 6 are transmitted to the top sub 2 through the shank rod 7. The rotational force and the striking force transmitted to the top sub 2 are sequentially propagated to the outer rod sub 3, the outer rod coupling 12, the outer rod 32, and the first casing 34, and are transmitted to the outer bit 33.

On the other hand, with respect to the inner rod sub 4, the striking force is not transmitted from the top sub 2 because the inner rod sub 4 is at the forward position separated from the top sub 2. Only the rotational force is transmitted from the outer rod sub 3 to the inner rod sub 4 via the splines 18 and 19. The rotational force transmitted to the inner rod sub 4 sequentially propagates to the inner rod 35, the starting rod 36, the adapter sub 37, and the down the hole hammer 39, and is transmitted to the hammer bit 38.

During excavation, compressed air generated by an air compressor (not shown) is added with lubricating oil for down-the-hole hammer by a line oiler (not shown), and then the annular air is passed through the air inlet 26 of the swivel case 5. It flows into the chamber 23. At that time, a small amount of fresh water may be mixed into the compressed air by a water injection pump in rare cases for the purpose of preventing dust scattering.

The compressed air further flows into the air flow path 9 and is supplied to the down the hole hammer 39 through the insides of the inner rod sub 4, the inner rod 35, the starting rod 36 and the adapter sub 37. This compressed air operates a piston incorporated in the down the hole hammer 39 to give a hammering force to the hammer bit 38. At this time, compressed air is intermittently ejected from the tip of the hammer bit 38. The ejected air passes through the gap between the outer rod 32 and the inner rod 35 in the direction opposite to that at the time of air supply, and reaches the gap 31 between the outer rod sub 3 and the inner rod sub 4. Further, the jetted air is discharged to the outside from the cuttings outlet 28 through the communication hole 30 and the annular cutting chamber 25, and the airflow conveys and discharges the cuttings to the ground.

As shown in FIG. 1, the small diameter portion 13 of the inner rod sub 4 has such a length that it is always fitted and held in the axial portion 9a of the air flow passage 9 via the seal ring 40. Therefore, the inner rod sub 4 strokes (S in Fig. 1
Even when fully advanced (indicated by 1), the small diameter portion 13 does not slip out of the axial portion 9a.

To achieve the flushing state of FIG. 5 (b), hydraulic oil of a predetermined pressure is supplied from the hydraulic oil inlet / outlet 27a to the hydraulic cylinder front chamber 15a through the annular oil chamber 24a and the communication hole 29a. As a result, the inner rod sub 4 retracts, the hammer bit 38 of the down the hole hammer 39 separates from the bottom of the drill hole, the hammer bit 38 descends by the bit stroke S2, and the entire amount of compressed air is ejected. This jet of air effectively removes the cuttings remaining at the bottom of the drill hole, and the cuttings are transported and discharged to the ground through the same route as when excavating.

The annular partition wall portion 14 provided on the outer rod sub 3 has an axial length longer than the stroke amount of the inner rod sub 4. Therefore, even if the dust seal 41 provided on the inner rod sub 4 is worn and the inner rod sub 4 is retracted to the stroke end with cuttings and mud attached to the outer periphery of the inner rod sub 4, these will not be directly It is not drawn into the hydraulic cylinder front chamber 15a.

According to the above embodiment, the following operational effects are brought about. (1) Since the inner rod 35 is structured so as not to be directly hit by the hydraulic drill head at the forward position, which is the excavation position, the down-the-hole hammer attached to the tip of the inner rod is not hit and special reinforcement is required. do not need. (2) Since the hammer bit 38 receives only the striking force by the down-the-hole hammer, it is not necessary to consider the influence that is conventionally exerted by the striking force by the hydraulic drill head having a different frequency.

(3) Since the inner rod sub 4 can be moved forward and backward at any time by hydraulic pressure,
The flushing operation can be performed without stopping the impact of the hydraulic drill head on the outer rod sub. (4) By setting the stroke amount of the inner rod sub 4 to be sufficiently larger than the stroke required for flushing operation, it becomes possible to finely adjust the axial front-rear positional relationship between the outer bit and the hammer bit. You can excavate according to the conditions.

(5) The cleaning swivel according to the present invention has the same function as the cleaning swivel, which is always used in the double pipe excavation method using the rotary percussion drill, with respect to the discharge of cuttings. There is no scattering of cuttings. (6) In the conventional double pipe excavation method using the rotary percussion drill, the impact force of the hydraulic drill head is dispersed and transmitted to both the outer bit and the inner bit. On the other hand, when the cleaning swivel according to the present invention is used, the impact force of the hydraulic drill head is transmitted only to the outer bit, so that the excavation efficiency on the outer side is improved.

(7) The cleaning swivel according to the present invention can be used by replacing it with the cleaning swivel that is always used in the double pipe excavation method using the rotary percussion drill, and therefore the existing excavator can be used as it is. .

[0034]

As described above, according to the present invention, the impact force of the drill head is not transmitted to the inner pipe in the rotary percussion type double pipe excavation method in which the down-the-hole hammer is attached to the tip of the inner pipe for excavation. Therefore, various effects on the down the hole hammer can be avoided. Further, since the flushing operation can be performed without stopping the impact on the outer pipe, the excavation efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an axial sectional view showing an embodiment of a cleaning swivel according to the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is an exploded sectional view of the cleaning swivel.

FIG. 4 is a cross-sectional view showing a state in which a cleaning swivel is connected to a hydraulic drill head.

FIG. 5 is an axial cross-sectional view showing a state of excavating together with a down the hole hammer.

[Explanation of symbols]

1: Cleaning swivel 2: Top sub 3: Outer rod sub 4: Inner rod sub 5: swivel case 6: Hydraulic drill head 7: Shank rod 9: Air flow path 9a: Axial part 9b: Radial portion 12: Outer rod coupling 13: Small diameter part 14: Ring partition 15: Hydraulic cylinder chamber 15a: hydraulic cylinder front chamber 15b: hydraulic cylinder rear chamber 17: Piston 18: Female spline 19: Male spline 23: Annular air chamber 24a: annular oil chamber 24b: annular oil chamber 25: Circular cutting room 26: Annular air chamber 26: Air inlet 27a: hydraulic oil inlet / outlet 27b: hydraulic oil inlet / outlet 28: Cuttings outlet 29a: communication hole 29b: communication hole 30: Communication hole 31: Void 32: Outer rod 33: Outer bit 34: First casing 35: Inner rod 36: Starting rod 38: Hammer bit 39: Down the Hole Hammer

Claims (3)

[Claims] 1. A cleaning swivel for connecting between a drill head that generates a rotational force and a striking force, and a double pipe consisting of an inner pipe and an outer pipe, the rear end being connected to the drill head, and the front end. A top sub having an air flow path consisting of an axial portion opening to the outside and a radial portion opening to the outer periphery, and an annular partition wall formed on the inner periphery of the middle portion of which the rear end is fixed to the outer periphery of the front end And an outer rod sub having a hydraulic cylinder chamber defined between the top sub and the top sub, and an outer rod sub axially movably inserted into the outer rod sub, the rear end of which is an axial portion of the air passage. An inner rod sub in which an intermediate portion is slidably fitted in the annular partition wall, and a piston that is slidable in the hydraulic cylinder chamber is provided on the outer periphery, and an inner rod sub from the outer rod sub. Means for transmitting a rotational force to the sub-sub, rotatably fitted to the outer peripheries of the top sub and the outer rod sub, and having an annular air chamber, two front and rear annular liquid chambers and an annular cutting chamber on the inner periphery. And a swivel case having an air inlet, two liquid inlets and outlets, and a cuttings outlet that communicate with the annular air chamber, the two annular liquid chambers, and the annular cuttings chamber, respectively. The annular air chamber communicates with a radial portion of the air flow passage, and the two front and rear annular liquid chambers communicate with the front and rear chambers of the cylinder chamber through communication holes provided in the outer rod sub, respectively. The cutting chamber communicates with a space between the outer rod sub and the inner rod sub through a communication hole provided in the outer rod sub. Rotary percussion double tube drilling equipment for cleaning swivel to the butterflies. 2. A small diameter portion is formed at a rear end portion of the inner rod sub, and the small diameter portion is slidably fitted to an axial portion of the air flow passage. Cleaning swivel for rotary percussion type double pipe excavator as described. 3. The means for transmitting a rotational force from the outer rod sub to the inner rod sub is a spline formed on the inner circumference of the outer rod sub and the outer circumference of the inner rod sub, and fitted to each other. The cleaning swivel for a rotary percussion type double pipe excavator according to claim 1 or 2, wherein