JP2008057293A - Double pipe-type excavation equipment and construction method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide double pipe-type excavation equipment which can surely continue the reciprocating motion of a piston of a down-the-hole drill even if soft ground is excavated, and a construction method for the double pipe-type excavation equipment. <P>SOLUTION: This double pipe-type excavation equipment 1 comprises: an excavator body (an ascending/descending block 60, a tilting block 70 and an excavation driving block 80) which is hoisted/lowered by being guided by a support 47; an excavation pipe 5, the upper end of which is connected to the excavation driving block 80, and the lower end of which is installed in the inner bit 10 of a double excavation bit 3 via the down-the-hole drill 100; and a casing 7, the upper end of which is connected to the excavation driving block 80 via a casing pull-back mechanism 200, and the lower end of which is installed in the outer bit 20 of the double excavation bit 3 via a casing shoe 6. Since the casing 7 is pulled back upward by the casing pull-back mechanism 200 when the double excavation bit 3 descends, the hitting motion of the down-the-hole drill 100 is continued. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a double-pipe excavator and a construction method thereof, and particularly to a double-pipe excavator equipped with a down-the-hole drill and a construction method thereof.

Conventionally, when drilling a stratum mixed with pebbles or hard strata such as hard strata, a down-the-hole drill is installed at the tip of the drill pipe (same as the drill rod), which gives striking force to the drill drill. It has been. In addition, excavation with a double-pipe excavator has been carried out when the wall of the excavation hole is easy to collapse or when a concrete-filled pile is installed.
And as a double-pipe excavator that can increase the excavation speed with a simple structure, a casing to which an outer bit (same as a ring bit) is connected, and an inner bit and a down-the-hole drill are connected to the casing. And a drilling force transmission means for transmitting a striking force applied to the inner bit to the outer bit is disclosed (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 8-312278 (page 3-4, FIG. 1)

  However, the down-the-hole drill included in the invention disclosed in Patent Document 1 has a piston disposed therein so as to be able to advance and retreat (lift up and down) in the axial direction. The compressed air flows into the chamber) or the rear chamber (rear chamber) and operates as follows, and thus has the following problems.

(A) In other words, when the piston is moving forward (down) to near the forward limit, the compressed air flows into the rear of the piston (the space before the rear chamber is formed) and passes through the piston through-hole (in the axial direction). It is ejected from the through hole of the drill bit into the drilling hole.
(Yes) Then, when the piston is slightly retracted (raised), compressed air flows into the front chamber, and the piston is retracted (raised) by the pressure.
(U) Then, when the piston is retracted (raised) to a predetermined position, the flow of compressed air into the front chamber stops, but the piston is retracted (raised) due to the expansion of the compressed air already flowing and the inertia of the piston. ) Continue.

(E) When a rear chamber is formed behind the piston, compressed air flows into the rear chamber, and the compressed air that flows in is further compressed to high pressure and stored by the rise of the piston. During this time, the compressed air in the front chamber is ejected from the drilling bit through the drilling hole.
(O) Eventually, the piston is pushed back by the compressed air (high pressure) in the rear chamber, and the piston retreats (ascends). At the same time, the piston rapidly expands due to the expansion of the compressed air in the rear chamber. Move forward (down). That is, the piston strikes the inner bit with a large amount of energy and moves forward (lowers) to near the forward limit.
Since the piston excavates the ground by striking the inner bit (same as striking the ground), it is normally rebounded by the ground reaction force at the time of striking. The piston continues to reciprocate.

However, in the down-the-hole drill, since (ii) is not executed for the following reasons, it is impossible to excavate the soft ground that is easy to excavate, and when the soft ground is reached during excavation, the excavation is continued. There was a problem that could not.
That is, in soft ground, even if the piston hits the inner bit (same as hitting the ground), since the ground reaction force at the time of hitting is small, the amount of retreat (lift) of the piston is insufficient. For this reason, the compressed air flows into the rear of the piston, passes through the through hole of the piston, and is only ejected from the through hole of the excavation bit into the drilling hole (the same as (a) above). (The above (I) is not executed). In particular, such a phenomenon is prominent when the friction between the outer surface of the casing and the inner surface of the excavation hole or the earth and sand collapsed into the excavation hole is large.

  The present invention has been made to solve such a problem, and even when excavating soft ground, a double-pipe excavation that can reliably continue the reciprocating motion of a piston of a down-the-hole drill. It aims at providing an apparatus and its construction method.

(1) The construction method of the double-pipe excavator according to the present invention is as follows:
An inner bit having a drilling blade;
A down-the-hole drill that imparts a striking force toward the excavation direction to the inner bit;
A drill pipe connected to the down-the-hole drill;
An outer bit having a drilling blade, to which a striking force applied to the inner bit is transmitted;
A casing connected to the outer bit;
In a double-pipe drilling rig having
Supplying compressed air to the down-the-hole drill to impart a striking force directed to the drilling direction to the inner bit and the outer bit;
Applying a pulling force in a direction opposite to the excavation direction to the outer bit;
It is characterized by having.

(2) The double-pipe excavator according to the present invention is
An inner bit having a drilling blade;
A down-the-hole drill that imparts a striking force toward the excavation direction to the inner bit;
A drill pipe having a lower end connected to the down-the-hole drill;
An outer bit having a drilling blade, to which a striking force applied to the inner bit is transmitted;
A casing having a lower end connected to the outer bit;
An elastic member connecting the upper end of the excavation pipe and the upper end of the casing;
It is characterized by having.

(3) An inner bit provided with a drilling blade;
A down-the-hole drill that imparts a striking force toward the excavation direction to the inner bit;
A drill pipe having a lower end connected to the down-the-hole drill,
An excavator body connected to the excavation pipe and supplying compressed air to the down-the-hole drill via the excavation pipe;
An outer bit having a drilling blade, to which a striking force applied to the inner bit is transmitted;
A casing having a lower end connected to the outer bit;
An elastic member that connects the excavator body and the upper end of the casing;
It is characterized by having.

(4) Further, in the above (2) or (3), the elastic member biases the casing in a direction opposite to the excavation direction.
(5) Furthermore, in (3) or (4), the excavator body rotates the inner bit via the excavation pipe together with the supply of the compressed air,
Rotation of the inner bit is transmitted to the outer bit together with the striking force,
The casing is rotatably connected to the outer bit in the circumferential direction.

(I) Since the construction method of the double-pipe excavator according to the present invention includes a step of applying a pulling force in the direction opposite to the excavation direction to the outer bit, the inner bit is pulled back by pulling back the outer bit. As a result, the piston of the down-the-hole drill is surely retracted (raised), so that the reciprocating motion of the piston is continued and the soft ground can be excavated.
(Ii) Moreover, since the double-pipe excavator according to the present invention has an elastic member that connects the upper end of the excavation pipe and the upper end of the casing, when the piston of the down-the-hole drill hits the inner bit, Since the elastic member is extended, excavation by the inner bit and the outer bit is performed. Further, after the impact, the elastic member returns to its original state, and therefore the inner bit is pulled back by the retreat (advance) of the casing (same as the outer bit). As a result, the piston of the down-the-hole drill is surely retracted (raised), so that the reciprocating motion of the piston continues, and the soft ground can be excavated.

  (Iii) Moreover, since it has the elastic member which connects an excavator main body and the upper end part of a casing, there exists the same effect as said (ii).

(Iv) Furthermore, since the elastic member urges the casing in the direction opposite to the excavation direction, the retreat (rise) of the piston of the down-the-hole drill after hitting is further ensured, so that the reciprocation of the piston continues, Excavation of soft ground becomes possible.
(V) Further, since the striking force and the rotation are transmitted to the inner bit and the outer bit, respectively, the excavation efficiency is improved and the construction is quickened. At this time, since the casing does not rotate, the excavator body only needs to supply power for rotating the inner bit and the outer bit, and does not require any extra power.

(Double pipe type drilling rig)
FIG. 1 schematically shows a double-pipe excavator according to an embodiment of the present invention, in which (a) is a front view and (b) is a side view. In FIG. 1, a double-pipe excavator 1 includes a substrate block 30 placed on the ground 2, a support block 40 that is detachably provided on the substrate block 30, and a support that is provided on the support block 40. A sheave block 50 installed at the tip of 47, an elevating block 60 that is guided up and down by a support 47 provided upright on the support block 40, a tilting block 70 that is tiltably installed on the elevating block 60, and a support block And a winch block 90 that is detachably installed at 40 (hereinafter, these may be collectively referred to as “device members”).

Then, the excavation drive block 80 is installed in the tilting block 70, the excavation hydraulic motor 84 constituting the excavation drive block 80 rotates the excavation pipe 5, and the compressed air receiving portion 86 constituting the excavation drive block 80 serves as the excavation pipe. Compressed air is supplied into 5.
The double excavation bit 3 includes an inner bit 10 that is directly connected to the excavation pipe 5 and an outer bit 20 that is detachably attached to the inner bit 10. The outer shoe 20 is provided with a casing shoe 6 that is rotatable in the circumferential direction and constrained in the axial direction. A casing 7 is connected to the casing shoe 6. Further, the casing 7 is pulled upward by the casing pulling mechanism 200 (this will be described in detail separately).
The present invention does not limit the raising / lowering mechanism of the tilting block 70, and the tilting block 70 may be guided directly to the column 47, that is, integrated with the lifting block 60, and the column 47 is publicly known. It may be a guide shell mast of the excavator.

(Drilling pipe)
FIG. 2 is a cross-sectional view in side view schematically showing a drill pipe in the double-pipe excavator according to the embodiment of the present invention. In FIG. 2, the down-the-hole drill 100 and the double excavation bit 3 are installed at the tip of the excavation pipe 5 (same as the drill rod).
The double excavation bit 3 includes an inner bit 10 connected to the down-the-hole drill 100 and an outer bit 20 detachably joined to the inner bit 10. The outer bit 20 has a casing through a casing shoe 6. 7 is connected rotatably in the circumferential direction.

(Down the hole drill)
The down-the-hole drill 100 is a known one, and includes a case 101 connected to the excavating pipe 5, a piston 102 disposed in the case 101 and reciprocating in the axial direction, a hammer 103 similarly reciprocating, and a predetermined number. And each member (not shown) for forming a flow of compressed air. The hammer 103 cannot be removed from the case 101, and the inner bit 10 constituting the double excavation bit 3 is installed at the tip (lower end).
In addition, since a spline is formed on the outer periphery of the hammer 103 and the spline meshes with the spline formed on the inner periphery of the case 101, the rotation applied to the case 101 is transmitted to the hammer 103. . When excavating without rotating the inner bit 10, the hammer 103 may be rotatable with respect to the case 101 by saving the formation of the spline.

(Inner bit)
The inner bit 10 that constitutes the double excavation bit 3 is provided with a substantially annular impact imparting portion 12 that protrudes toward the outer peripheral side in a range close to the front surface (lower surface in the drawing) of the outer peripheral portion 11. The front surface (lower slope) forms an impact imparting surface 12a, and a rotation imparting portion 15 (protruding to the outer peripheral side) having an axial step is provided behind the impact imparting portion 12 (upper side in the figure). The side surface on the rotation direction side during excavation of the rotation applying portion 15 forms a rotation applying surface 15a. Moreover, the outer peripheral part 11 and the hit | damage provision part 12 are parted by the four notch grooves 14 provided in the axial direction.

(Outer bit)
On the other hand, the outer bit 20 constituting the double excavation bit 3 is provided with a substantially annular hit receiving portion 22 projecting toward the inner peripheral side in a range close to the front surface, and a rear surface (upper side) on the inner peripheral side of the hit receiving portion 22. The slant surface) forms the impact receiving surface 22a. Further, a rotation receiving portion 25 (projecting toward the inner peripheral side) having a step in the axial direction is installed behind the impact receiving portion 22, and the side opposite to the rotation direction during excavation of the rotation receiving portion 25 is the rotation receiving portion. A surface 25a is formed. Further, an annular outer peripheral groove 24 is formed on the outer peripheral surface of the outer bit 20.

(Double drilling bit)
Therefore, when the inner bit 10 is attached to the outer bit 20, the axial striking force applied to the inner bit 10 (applied via the hammer 103 by the lowering of the piston 102 of the down-the-hole drill 100) is abutting striking. It is transmitted to the outer bit 20 through the application surface 12a and the impact receiving surface 22a.
Further, the circumferential rotation imparted to the inner bit 10 (given by the excavation drive block 80 via the excavation pipe 5) is applied to the outer bit 20 via the abutting rotation imparting surface 15a and the rotation receiving surface 22a. Is transmitted to.

  When the inner bit 10 is pressed against the bottom of the excavation hole (receives a force lifting upward) and rotates in a direction opposite to the rotation direction during excavation, the outer bit 20 is inserted into the notch groove 14 of the inner bit 10. The rotation receiving portion 25 enters. Therefore, if the inner bit 10 is pulled back in the intrusion state (same as pulling back the excavation pipe 5), the inner bit 10 can be separated from the outer bit 20 and the inner bit 10 can be collected on the ground. (For details, see Japanese Patent Application No. 2003-387281).

(Casing shoe)
An annular inner circumferential groove 6 a is formed on the inner surface of the casing shoe 6, and a C-shaped elastic member 6 b is disposed in an annular space formed by the inner circumferential groove 6 a and the outer circumferential groove 24 of the outer bit 20. ing. That is, the casing shoe 6 is constrained in the axial direction and is rotatably connected in the circumferential direction to the outer bit 20 by the elastic member 6b.

(Drilling drive block)
FIG. 3 schematically shows an excavation drive block in the double-pipe excavator according to the embodiment of the present invention, where (a) is a side view, (b) is a front view, and (c) is a back view. It is. In FIG. 3, the excavation drive block 80 is installed on the tilting block 70, and the tilting block 70 is installed on the lifting block 60 so as to be tiltable (this will be described in detail separately). The tilt block 70 is provided with a casing pullback mechanism 200 (the same as that provided in the excavation drive block 80).
In the present invention, the one in which the excavation drive block 80 and the tilting block 70 are integrated corresponds to the “excavator body”. Further, when the tilting block 70 and the lifting block 60 are integrated (when the tilting block 70 does not tilt with respect to the lifting block 60), the excavation drive block 80, the tilting block 70, and the lifting block 60 are integrated. This corresponds to the “excavator body”.

The excavation drive block 80 includes a excavation pipe connection portion 81 for connecting the excavation pipe 5, a excavation hydraulic motor 84 that rotationally drives the excavation pipe connection portion 81, and compressed air supplied to the excavation pipe 5 (more precisely, A compressed air receiving portion 86 that receives the compressed air that is supplied to the down-the-hole drill 100 and is ejected from the through hole formed in the inner bit 10 into the drill hole.
The excavation pipe connection portion 81 is a blind hole having a hexagonal cross section, and is formed with a drop prevention hole 82 into which a drop prevention pin (not shown) is driven. When the end portion of the excavating pipe 5 is not formed in a columnar shape having a hexagonal cross section, for example, in the case of a quadrangular cross section, the blind hole of the excavating pipe connecting portion 81 is not a hexagonal cross section, but a cross section 4 It will be formed in a square shape.

The compressed air receiving portion 86 has a cylindrical shape that sends compressed air to the excavation pipe connecting portion 81 that receives and rotates the compressed air, and a compressed air joint 87 projects from the outer surface to connect a compressed air hose (not shown).
The excavating hydraulic motor 84 is a known type, and a hydraulic joint 85 projects from the outer surface to connect a hydraulic hose (not shown). In addition, when excavating without rotating the excavation pipe 5, the excavating hydraulic motor 84 is removed.
The casing pullback mechanism 200 includes a pullback bar 210 installed on the flange 76 of the tilting block 70, a pullback body 220 that moves (lifts and moves) while being guided by the pullback bar 210, and a pullback bolt 230 that connects the pullback body 220 to the casing 7. And have.

(Case retraction mechanism)
4 to 7 schematically show a casing pull-back mechanism in the double-pipe excavator according to the embodiment of the present invention, and FIG. 4 is a partial cross section of the first type (tilting block, semi-cylindrical, screw installation type). 5 is a side view of a partial cross section of the second type (tilting block / semi-cylinder / pin installation type), and FIG. 6 is a partial cross section of the third type (tilting block / bar / insertion type). FIG. 7 is a side view and FIG. 7 is a perspective view of a fourth type (excavated pipe / bar / insertion type).

(First type: tilting block, semi-cylinder, screw installation type)
4 and 3, a flange 211 is installed at the rear end of the pull-back rod 210, and the flange 211 is fixed (welded) to the flange 76 of the tilting block 70. Note that the fixing procedure is not limited, and through holes may be formed in the flange 211 and the flange 76 of the tilting block 70 and mechanically joined by bolts / nuts, or the flange 211 may be tilted. The flange 76 may be engaged (gripped).

  The pullback bar 210 passes through the upper coil spring 212 and the lower coil spring 213, and a pullback screw 215 is formed at the tip of the pullback bar 210. Accordingly, the upper coil spring 212 and the lower coil spring 213 are clamped with a predetermined compressive force by screwing the pullback nut 214 into the pullback screw 215 and tightening it. Note that a predetermined step is formed on the pull-back rod 210, and a washer that contacts the step and the upper coil spring 212 and a washer that contacts the lower coil spring 213 and the nut 214 are disposed. As will be described later, the lower coil spring 213 may be omitted and only the upper coil spring 212 may be installed.

The pull-back body 220 includes a semi-cylindrical portion 221, a pull-back arm 222 that protrudes upward in the axial direction from a diagonal position in a plan view of the semi-cylindrical portion 221, and an outer side (semi-cylindrical portion in a plan view of the pull-back arm 222 And a pair of pull-back flanges 223 protruding in the radial direction of 221.
A pull-back through hole 224 is formed in the pull-back flange 223, and the pull-back bar 210 passes through the pull-back through hole 224. At this time, since the upper coil spring 212 and the lower coil spring 213 are disposed on both sides (upper and lower) of the pullback flange 223, the pullback flange 223 is clamped with a predetermined force by both. Note that washers that contact the upper coil spring 212 and the lower coil spring 213 may be disposed on both surfaces of the pull-back flange 223.

The semi-cylindrical portion 221 of the pull-back body 220 is formed with a pull-back screw hole 225 at a diagonal position in plan view, and a pull-back bolt 230 is screwed into the pull-back screw hole 225.
The pullback bolt 230 has a bolt screw portion 232 that is screwed into the pullback screw hole 225 and a casing hole intrusion portion 233 that enters the casing hole 7 a formed in the casing 7. In addition, although the hexagonal column-shaped bolt head 231 is illustrated as the pullback bolt 230, a hexagon socket head cap screw may be used instead of the hexagon bolt.

(Second type: tilting block, semi-cylinder, pin installation type)
5A is a partially sectional side view, FIG. 5B is a partially sectional plan view, and FIG. 5C is a front view showing a retaining clip. In FIG. 5, the casing pullback mechanism 200b is connected to the casing 7 by a pin mechanism instead of the screw mechanism (the pullback mechanism 200).
That is, a pull-back pin hole 226 is formed at a diagonal position in plan view of the semi-cylindrical portion 221b, and a cylindrical protrusion 240 having a cylindrical protrusion pin hole 241 communicating with the pull-back pin hole 226 is formed on the outer surface of the semi-cylindrical portion 221b. is set up. The cylindrical protrusion 240 is formed with a cylindrical protrusion lateral hole 242 that is perpendicular to the central axis of the cylindrical protrusion 240 and passes through the central axis.

The pull-back pin 250 passes through the central axis perpendicular to the central axis of the pin cylindrical portion 251 and the pin cylindrical portion 251 having an outer diameter that can enter the casing hole 7a, the pull-back pin hole 226, and the cylindrical projection pin hole 241. A pin lateral hole 252 and a ring-shaped pin grip portion 253 provided at one end of the pin cylindrical portion 251 are provided.
The clip prevention clip 260 includes a linear insertion portion 261, a grip portion 262 bent in a semicircular shape, and a calling portion 263 that opens in a substantially V shape with respect to the distal end of the insertion portion ( (See (c) of FIG. 5).

Accordingly, the phases of the casing hole 7a and the pull-back pin hole 226 (same as the cylindrical protrusion pin hole 241) are matched, and the pull-back pin 250, the cylindrical protrusion pin hole 241, the pull-back pin hole 226, the casing hole 7a, If it installs so that it may penetrate, casing 7 and casing pullback mechanism 200b can be connected.
Furthermore, if the phase of the pin horizontal hole 251 of the pull-back pin 250 and the cylindrical protrusion horizontal hole 242 of the cylindrical protrusion 240 are matched, and the insertion portion 261 of the drop prevention clip 260 is inserted here, the pull-back pin 250 will not come out.

That is, if the distal end of the insertion portion 261 of the slip-off preventing clip 260 is inserted into the cylindrical projection lateral hole 242 and the calling portion 263 is pressed against the outer surface of the cylindrical projection 240 and pushed in, the calling portion 263 expands due to elastic deformation, The insertion portion 261 passes through the pin lateral hole 251 and the cylindrical projection lateral hole 242. At this time, the calling portion 263 once expands and then returns to the original shape, so that the grip portion 262 grips the outer surface of the cylindrical protrusion 240.
Then, unless the call-in portion 263 is expanded again, the removal prevention clip 260 does not come out, so that the pull-back pin 250 does not come out.

(Third type: tilting block, bar, insertion type)
In FIG. 6, in the casing pullback mechanism 200 c, a through hole 76 a is formed in the flange 76 of the tilting block 70. The pullback bar 310 penetrates the lower coil spring 213, the flange 76 through the through hole 76 a and the upper coil spring 212, and a pullback screw 315 is formed at the tip of the pullback bar 310. Accordingly, the pull-back nut 314 is screwed onto the pull-back screw 315 and tightened, whereby the flange 76 of the tilting block 70 is clamped with a predetermined compression force by the upper coil spring 212 and the lower coil spring 213. . As will be described later, the lower coil spring 213 may be omitted and only the upper coil spring 212 may be installed.

Further, a casing hole intrusion portion 330 bent perpendicularly to the axial direction of the pullback rod 310 is formed at the lower end portion of the pullback rod 310, and the casing hole intrusion portion 330 is formed at the upper end portion of the casing 7. It penetrates into the hole 7a.
The number of pullback bars 310 is not limited to two, and may be three or more. Further, a ring for preventing the spread may be attached or tied together so that the interval between the plurality of pullback bars 310 is not widened.
Further, in FIG. 6, the casing hole intrusion portion 330 enters from the outside of the casing 7, but the present invention is not limited to this, and enters the casing hole 7 a from the inside to the outside of the casing 7. Also good. At this time, the pull-back bar 310 is bent (kinked) so as not to interfere with the excavation pipe connecting portion 81 of the excavation drive block 80.

(4th type: excavation pipe / bar / insertion type)
In FIG. 7, in the casing pullback mechanism 200, 200b, 200c (first, second, and third types), the pullback rod 210 is installed on the tilting block 70, whereas in the casing pullback mechanism 200d (fourth type), the pullback is performed. A rod 430 is installed in the excavation pipe 5. That is, the excavation pipe flange 501 in which the through hole 502 is formed is fixed to the upper end portion of the excavation pipe 5, and the pull-back bar 430 passes through the through hole 502.

  That is, the pullback bar 310 passes through the upper coil spring 212, the through hole 502 of the excavation pipe flange 501, and the lower coil spring 213, and a pullback screw 315 is formed at the tip of the pullback bar 310. Therefore, by screwing the pull back nut 314 into the pull back screw 315 and tightening it, the excavated pipe flange 501 is pinched by the upper coil spring 212 and the lower coil spring 213 with a predetermined compressive force. As will be described later, the lower coil spring 213 may be omitted and only the upper coil spring 212 may be installed.

Further, a casing hole intrusion portion 330 bent perpendicularly to the axial direction of the pullback rod 310 is formed at the lower end portion of the pullback rod 310, and the casing hole intrusion portion 330 is formed at the upper end portion of the casing 7. 7a has been invaded.
In FIG. 7, the casing hole intrusion portion 330 has entered the casing hole 7 a from the inside to the outside of the casing 7, so that the outer diameter of the drill pipe flange 501 is as small as the outer diameter of the casing 7. However, the present invention is not limited to this, and may enter the casing hole 7a from the outside toward the inside. Further, in accordance with the first type, a pullback screw hole 225 is formed in the lower end portion of the pullback rod 310, and the pullback rod 310 and the casing 7 are connected by a pullback bolt 230 screwed into the pullback screw hole 225. Good. Furthermore, the number of pull-back bars 310 is not limited to two, and may be three or more. Moreover, you may provide the constraining means which restrains a mutual position after the said insertion so that the space | interval of several pullback bars 310 may not change.

(Construction method)
Since the double-pipe excavator 1 has the above-described configuration, it is possible to form a drilling hole in the ground in the same manner as a construction method using a known down-the-hole drill.
[Step 1] That is, the inner bit 10 and the outer bit 20 are detachably attached to the excavating pipe 5 in which the inner bit 10 and the down-the-hole drill 100 are installed and the casing 7 in which the outer bit 20 is installed through the casing shoe 6. It is united by connecting to.
[Step 2] The excavation pipe 5 is connected to the excavation pipe connection portion 81 of the excavation drive block 80.
[Step 3] Further, the casing 7 is connected to the tilting block 70 (same as the excavation drive block 80) through the casing pulling back mechanism 200. That is, the casing 7 is elastically and movably connected to the tilting block 70 (same as the excavation drive block 80). Therefore, when an axial load is applied to the casing 7, the upper coil spring 212 is applied. When the axial load applied to the casing 7 is removed, the upper coil spring 212 and the lower coil spring 213 are restored to their original positions when the axial load applied to the casing 7 is removed. Will return.

[Step 4] Then, the integrated excavation pipe 5 and casing 7 are arranged vertically or at a predetermined inclined angle at a position where an excavation hole is formed.
[Step 5] Then, as in normal excavation, the compressed air is sent to the down-the-hole drill 100 and the excavation pipe 5 is rotated. Then, the piston 102 of the down-the-hole drill 100 strikes the hammer 103 connected to the inner bit 10. The rotation of the drill pipe 5 is transmitted to the inner bit 10 via the case 101 of the down-the-hole drill 100. Since the outer bit 20 and the inner bit 10 are combined together, excavation is performed by striking and rotating the two (same as the double excavation bit 3).

  At this time, since the casing 7 is connected to the tilting block 70 (same as the excavation drive block 80) via the casing pullback mechanism 200, the double excavation bit 3 was hit in the excavation direction (for example, downward). Thereafter, the upper coil spring 212 and the lower coil spring 213 are pulled back in the direction opposite to the excavation direction (for example, upward) by the restoring force to return to the original position. That is, when the casing 7 is pulled back, the hammer 103 and the piston 102 of the down-the-hole drill 100 are also pulled back through the double excavation bit 3 in which the casing 7 is installed.

  Accordingly, since the excavated ground is soft and the repulsive force when hitting the ground is small, the upper coil spring 212 and the lower coil are not affected by the repulsive force alone even if the piston 102 does not return to the predetermined position. Since the piston 102 returns to a predetermined position by the restoring force of the spring 213, a condition for the reciprocating motion of the piston 102 is formed, and repeated hammering of the hammer 103 is continued.

That is, even when excavating the ground in which the soft layer is interposed between the hard layers, the soft layer can be excavated by both striking and rotating the double excavation bit 3, so that high excavation efficiency is achieved. Is maintained, and the construction can be speeded up. Furthermore, according to the present invention, it is possible to use the down-the-hole drill 100 even for soft ground, which has conventionally been difficult to use the down-the-hole drill 100. Therefore, the construction can be speeded up for the above-described reason. .
Even if there is a considerable repulsive force when hitting the ground, there is a considerable amount of sliding resistance between the wall surface of the excavation hole and the outer surface of the casing 7, similarly to the above, the piston 102 Is returned to the predetermined position by the restoring force, so that the hammer 103 is repeatedly hit. That is, since the down-the-hole drill 100 can be used even on the ground where the wall surface of the excavation hole is easily collapsed, the construction can be speeded up for the reason described above.

  Since the magnitude of the restoring force is mainly determined by the elastic coefficient of the upper coil spring 212, the lower coil spring 213 is omitted and the upper coil spring 212 is installed alone. An effect can be obtained. The mechanism for generating the restoring force is not limited to the coil spring, and other elastic bodies (for example, an accordion-shaped leaf spring, a synthetic resin such as urethane) may be installed, and the pull-back is performed. The bar 210 itself may have an elastic structure (for example, a coil spring itself, a plate material bent in a substantially square shape, a urethane bar, etc.).

  Further, the description has been given above of the case where the double excavation bit 3 is provided with both hitting and rotation. However, the present invention is not limited to this. The drill bit 3 may not be rotated. At this time, the excavation hydraulic motor 84 of the excavation drive block 80 is unnecessary, and the splines formed in the case 101 and the hammer 103 of the down-the-hole drill 100 are also unnecessary, so the excavation hydraulic motor 84 is stopped or removed. Or the spline may be removed. In the double excavation bit, the outer bit may not be rotatable in the circumferential direction with respect to the inner bit.

[Step 6] Then, the excavation is terminated when the excavation hole having a normal depth is formed. That is, supply of the compressed air and application of rotation are stopped. Then, the excavation pipe 5 is rotated in the direction opposite to that at the time of excavation, the connection (combination) between the inner bit 10 and the outer bit 20 is released, the two are separated, and the excavation pipe 5 (inner bit 10 And the down-the-hole drill 100 are installed on the ground.
[Step 7] Furthermore, for the casing 7, for example, depending on the purpose of construction, it is left in the ground as it is, left in the ground while the mortar is injected therein, or mortar is injected into the inside And then recovered on the ground.

  Hereinafter, the other members constituting the double-pipe excavator 1 will be briefly described with reference to FIG.

(Board block)
In FIG. 1B again, the substrate block 30 is provided with a frame 31 whose lower surface forms a plane, a column block 31 for installing the column block in a detachable manner, and a substrate. When the block 30 is placed on the ground 2, it has a through hole (not shown) through which a peg (not shown) for preventing the movement and lifting of the block 30 passes.

(Support block)
The column block 40 is detachably installed on the substrate block 30, and the column block base 41, a column standing part 42 fixed to the upper surface of the column block base 41, and the casing 7 can be moved in the axial direction. The casing guide 43 is constrained in the direction perpendicular to the axial direction.
The column erecting portion 42 holds the column 47 perpendicular to the column block base 41 or at a predetermined angle. For example, when the column 47 is formed of a plurality of steel pipes, the column erecting portion 42 is provided. Is a steel pipe into which the plurality of steel pipes can be inserted.
Further, the casing guide portion 43 has a cylindrical shape through which the casing 7 can pass. In order to facilitate the penetration of the casing 7, a pair of semicircular members may be used, one of which may be fixed to the column block base 41 and the other fixedly attached to the fixed one.

(Sheave block)
The sheave block 50 includes a sheave 51, a sheave shaft 52 that rotatably supports the sheave 51, a sheave cover 53, and a sheave block installation portion (not shown) for installation at the tip of the column 47. Yes.
For example, when the support column 47 is formed of a steel pipe, the sheave block installation portion is a blind hole into which the steel pipe can be inserted.

(winch)
The winch block 90 is detachably installed on the support block 40, and includes a support plate 91, a lifting hydraulic motor 92 installed on the supporting plate 91, and a winding rotated by the lifting hydraulic motor 92. And a lifting wire (not shown) wound around the winding drum 93.

(Elevating block)
The elevating block 60 includes a pair of elevating plates 62 each having a through-hole (hereinafter referred to as “tilting hole”) 61 formed in the center, and a guide portion 63 that connects the pair of elevating plates 62. The pair of tilting holes 61 are coaxial, and a tilting shaft 71 installed in the tilting block 70 enters in a freely rotatable manner.
When a through hole is formed in the tilting block 70 instead of the tilting shaft 71, a shaft that slides into the through hole is installed in the lifting block 60 instead of the tilting hole 61. It will be.

  The guide portion 63 is engaged with the support column 47. For example, when the support column 47 is formed of a single steel pipe, the guide portion 63 is a cylinder or a C-shaped body through which the steel pipe penetrates. In the case of being formed by a plurality of steel pipes, it is a plurality of cylinders or C-shaped bodies that are locked to any of the plurality of steel pipes. Further, the lifting block 60 is provided with a handle 66 for handling and for facilitating the standing work of the column 47.

(Tilt block)
The tilting block 70 has a tilting shaft 71 and a tilting plate 74, and is detachably and tiltably attached to the lifting block 60 via the tilting shaft 71, and the excavation drive block 80 is fixed to the tilting plate 74.
The tilt shaft 71 is a cylinder having a drop prevention hole 72 formed at the tip, and is inserted into the tilt hole 61 provided in the lifting block 60. That is, when the tilting shaft 71 passes through the tilting hole 61, the slipping prevention pin 73 is driven into the slipping prevention hole 72, so that the tilting shaft 71 cannot be pulled out from the tilting hole 61 of the lifting block 60. Can be tilted (same as rotating) with respect to the lifting block 60.

  Since the tilting shaft 71 slides in the tilting hole 61, an oil groove may be provided on the outer periphery of the tilting shaft 71, or a bearing may be installed. Moreover, you may form with a steel pipe instead of a cylinder (round bar). Further, when a through shaft is formed in the lifting block 60 instead of the tilt hole 61, the tilt block 70 is provided with a hole through which the through shaft slidably enters instead of the tilt shaft 71. It will be. The tilting plate 74 is a rectangular plate, and is provided with a wire installation hole 75 for connecting a lifting wire (not shown).

  Further, a pair of flanges 76 are fixed along both side edges of the tilting plate 74, and an arm mounting plate 77 for mounting a counterweight arm 78 is fixed to the pair of flanges 76, and excavation driving is performed on the arm mounting plate 77. A substantially U-shaped counterweight arm 78 extending in a direction opposite to the excavation pipe connecting portion 81 of the block 80 is installed. Further, a counterweight screw rod 79 extending in the direction opposite to the excavation pipe connecting portion 81 is fixed to the counterweight arm 78.

  Therefore, since the counterweight 89 can be skewered on the counterweight screw rod 79 and fixed with the nut, it is possible to prevent the excavated pipe from being lifted during excavation. When the excavation pipe is installed in the excavation drive block 80, the tilting block 70 is balanced in weight by a counterweight (not shown). Therefore, when the lifting block 60 is pulled up, the tip of the excavation pipe (the excavation bit is installed). However, since the force which presses the ground 2 becomes weak, it becomes easy to pull up.

(Placement method at excavation position)
FIG. 8 is a side view schematically showing an example of an arrangement method for arranging the double-pipe excavator according to the embodiment of the present invention at the excavation position, and shows a plurality of steps in one figure. That is, the step 4 will be described in detail. That is, the case where the double excavation bit 3 is installed at the excavation pipe (not shown) and the tip of the casing 7 and the casing 7 is left in the excavation hole will be described. Note that some of the descriptions (hydraulic hoses, pneumatic hoses, lifting wires, etc.) are omitted.

[Step 4-1] First, the substrate block 30 is placed at a position where a drilling hole is to be formed (same as installation of the casing 7), and is fixed to the ground by a peg (not shown).
[Step 4-2] The support block 40 is installed on the substrate block 30.
[Step 4-3] The winch block 90 is installed on the support block 40. That is, the winch block 90 is detachably installed on the substrate block 30 via the support block 40.
[Step 4-4] With the elevating block 60 guided, the column 47 is installed on the column standing portion 42. At this time, a sheave block 50 (a sheave cover 53 is installed in a state where the lifting wire is locked to the sheave 51) is installed at the tip of the support column 47 in advance.

  [Step 4-5] A tilting block 70 (same as the excavation drive block 80) is tiltably installed on the lifting block 60 (guided by the support column 47). In other words, the tilting shaft 71 of the tilting block 70 is inserted into the tilting hole 61 of the lifting block 60, and the slipping prevention pin 73 is driven into the slipping prevention hole 72 in a state of passing through the lifting plate 62. At this time, the excavation drive block 80 is made to be substantially horizontal. Then, an elevating wire (not shown) is connected to the wire installation hole 75 of the tilting plate 74.

  [Step 4-6] Therefore, the excavation pipe 5 is connected to the excavation drive block 80. The connection is such that the end of the excavation pipe 5 is inserted into the excavation pipe connection portion 81 and a removal prevention pin (not shown) is driven into the removal prevention hole 82, and the excavation drive block 80 (same as the tilting block 70). Can be executed on the ground, and is easily and quickly executed. At this time, the integrated body of the drill pipe 5, the down-the-hole drill 100, and the inner bit 10 is inserted in advance into the integrated body of the casing 7, the casing shoe 6, and the outer bit 20, and the inner bit 10 and the outer bit 20 are connected. Combined (combined), a double drill bit 3 is assembled.

  [Step 4-7] Further, the upper end portion of the casing 7 and the excavation drive block 80 are connected via the casing pull-back mechanism 200. At this time, since the excavation drive block 80 (same as the tilting block 70) is substantially horizontal at a position close to the ground, the connecting work can be executed on the ground, so that the work becomes easy and quick.

[Step 4-8] The hydraulic hose and the pneumatic hose are connected to each other.
[Step 4-9] The excavator body (formed from the lifting block 60, the tilting block 70, and the excavation drive block 80) is pulled up by winding up the lifting wire. At this time, the rear end of the casing 7 which was initially substantially horizontal is pulled up, gradually rises, and eventually becomes parallel to the column 47 (for example, becomes vertical).
[Step 4-10] When the casing 7 is in parallel with the support 47, the lifting of the lifting wire is stopped, and the lower end of the casing 7 is inserted into the casing guide 43 installed in the support block 40. .

As described above, since the columns 47 are assembled at the construction site and the main body of the excavator is formed by a plurality of blocks, the entire apparatus is simple and can be easily transported to the construction site. Therefore, for example, it is suitable for construction on an upper part of an inclined land.
The double-pipe excavator of the present invention is not limited to the one installed on the assembly-type column as described above, and may be installed on a guide shell mast of a known excavator.
Further, the excavation drive block 80 is not limited to the one that tilts with respect to the support column, but is not tilted, that is, moves up and down while maintaining a posture parallel to the support column (or a known guide shell mast of an excavator). You may do. At this time, the connection between the excavation pipe 5 and the excavator body (same as the excavation drive block 80) and the connection between the casing 7 and the casing pull-back mechanism 200 are high positions after the excavation pipe 5 and the casing 7 are erected. (For example, on a stand installed at a predetermined height above the ground).

  The present invention can reliably continue the reciprocating motion of the piston of the down-the-hole drill regardless of the nature of the excavated ground. Alternatively, it can be widely used as a double-pipe excavation apparatus for forming excavation holes in various grounds such as soft ground and its construction method.

BRIEF DESCRIPTION OF THE DRAWINGS The double-pipe type excavation apparatus which concerns on embodiment of this invention is shown typically, Comprising: (a) is a front view, (b) is a side view. FIG. 3 is a cross-sectional view in side view schematically showing the excavation pipe in the double pipe excavator shown in FIG. 1. The excavation drive block in the double-pipe type excavator shown in FIG. 1 is typically shown, wherein (a) is a side view, (b) is a front view, and (c) is a back view. The side view of the partial cross section which shows typically the casing pullback mechanism (1st type, tilting block, semi-cylinder, screw installation type) in the double-pipe type excavator shown in FIG. The side view etc. of the partial cross section which show typically the casing pullback mechanism (2nd type, tilting block, semi-cylinder, pin installation type) in the double-pipe type excavator shown in FIG. The side view of the partial cross section which shows typically the casing pullback mechanism (a 3rd type, a tilting block, a stick | rod, insertion type) in the double-pipe type excavator shown in FIG. The perspective view which shows typically the casing pullback mechanism (4th type, excavation pipe | rod / rod | insert type) in the double pipe excavation apparatus shown in FIG. The side view which shows typically the example of the arrangement | positioning method which arrange | positions the double-pipe type excavator shown in FIG. 1 in an excavation position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double pipe type excavator 2 Ground 3 Double excavation bit 5 Excavation pipe 6 Casing shoe 6a Inner peripheral groove 6b Elastic member 7 Casing 7a Casing hole 10 Inner bit 11 Outer peripheral part 12 Impact imparting part 12a Impact imparting surface 14 Notch groove 15 Rotation imparting portion 15a Rotation imparting surface 20 Outer bit 22 Impact receiving portion 22a Impact receiving portion surface 24 Peripheral groove 25 Rotation receiving portion 25a Rotation receiving surface 30 Substrate block 31 Frame 32 Support block setting portion 40 Support block 41 Support block block 42 Column support section 43 Casing guide section 47 Column 50 Sheave block 51 Sheave 52 Sheave shaft 53 Sheave cover 60 Lift block 61 Tilt hole 62 Lift plate 63 Guide section 66 Handle 70 Tilt block 71 Tilt shaft 72 Escape prevention hole 73 Ejection prevention pin 74 Tilt plate 75 Wire installation hole 76 Flange 76a Through hole 77 Arm mounting plate 78 Counterweight arm 79 Counterweight screw rod 80 Excavation drive block 81 Excavation pipe connection part 82 Disengagement prevention hole 84 Excavation hydraulic motor 85 Hydraulic joint 86 Pneumatic receiving part 87 Pneumatic joint 89 Counterweight 90 Winch block 91 Support plate 92 Lifting hydraulic motor 93 Drum 100 Down-the-hole drill 101 Case 102 Piston 103 Hammer 200 Casing retracting mechanism 200b Casing retracting mechanism 200c Casing retracting mechanism 200d Casing retracting mechanism 210 Pulling rod 211 Flange 212 Upper coil spring 213 Lower coil spring 214 Pullback nut 220 Pullback body 221 Semi-cylindrical portion 223 Pullback Lung 224 Pull-back through hole 225 Pull-back screw hole 226 Pull-back pin hole 230 Pull-back bolt 231 Bolt head 232 Bolt screw portion 233 Casing hole intrusion portion 240 Cylindrical protrusion 241 Cylindrical protrusion pin hole 242 Cylindrical protrusion horizontal hole 250 Pull-back pin 251 Pin cylindrical portion 252 Pin lateral hole 253 Pin gripping part 260 Pull-out prevention clip 261 Insertion part 262 Holding part 263 Calling part 310 Pull-back bar 314 Pull-back nut 330 Casing hole intrusion part 430 Pull-back bar 501 Drilling pipe flange 502 Through-hole

Claims (5)

An inner bit having a drilling blade;
A down-the-hole drill that imparts a striking force toward the excavation direction to the inner bit;
A drill pipe connected to the down-the-hole drill;
An outer bit having a drilling blade, to which a striking force applied to the inner bit is transmitted;
A casing connected to the outer bit;
In a double-pipe drilling rig having
Supplying compressed air to the down-the-hole drill to impart a striking force directed to the drilling direction to the inner bit and the outer bit;
Applying a pulling force in a direction opposite to the excavation direction to the outer bit;
A construction method for a double-pipe excavator characterized by comprising: An inner bit having a drilling blade;
A down-the-hole drill that imparts a striking force toward the excavation direction to the inner bit;
A drill pipe having a lower end connected to the down-the-hole drill;
An outer bit having a drilling blade, to which a striking force applied to the inner bit is transmitted;
A casing having a lower end connected to the outer bit;
An elastic member connecting the upper end of the excavation pipe and the upper end of the casing;
A double-pipe excavator characterized by comprising: An inner bit having a drilling blade;
A down-the-hole drill that imparts a striking force toward the excavation direction to the inner bit;
A drill pipe having a lower end connected to the down-the-hole drill,
An excavator body connected to the excavation pipe and supplying compressed air to the down-the-hole drill via the excavation pipe;
An outer bit having a drilling blade, to which a striking force applied to the inner bit is transmitted;
A casing having a lower end connected to the outer bit;
An elastic member that connects the excavator body and the upper end of the casing;
A double-pipe excavator characterized by comprising:   The double-pipe excavator according to claim 2 or 3, wherein the elastic member biases the casing in a direction opposite to the excavation direction. The excavator main body rotates the inner bit via the excavation pipe together with the supply of the compressed air,
Rotation of the inner bit is transmitted to the outer bit together with the striking force,
The double-pipe excavator according to claim 3 or 4, wherein the casing is rotatably connected to the outer bit in a circumferential direction.

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