Attachment and a crushed stone pile forming device including the same

Abstract

To provide an attachment and a crushed stone pile forming device including the same, capable of reducing maintenance cost caused by wear on a cylindrical part.SOLUTION: An attachment 10 for forming crushed stone pile comprises: a cylindrical part 12 in which a crushed stone charging hole 15 is formed; and a door 20 attached on the cylindrical part 12 to open / close the crushed stone charging hole 15. The cylindrical part 12 is connected to a driving device 11 generating rotational driving force to form a space by excavating the ground through the rotational driving force. The cylindrical part 12 comprises: a plurality of cylindrical parts 12A, 12B; and one or a plurality of connection mechanisms 61 separably connecting the cylindrical parts 12A, 12B adjacent to each other in an axial direction. The plurality of cylindrical parts 12A, 12B comprise crushed stone charging hole parts. The crushed stone charging hole 15 is configured with the crushed stone charging hole parts formed in the plurality of cylindrical parts 12A, 12B. At least one of one or the plurality of connection mechanisms 61 are provided on inner peripheral surfaces of the two cylindrical parts 12A, 12B connected by the connection mechanisms 61.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to an attachment (for example, an attachment for forming gravel piles) attached to a ground improvement machine and a gravel pile forming apparatus including the attachment.

Background Art

[0002] When performing ground improvement, an attachment attached to a ground improvement machine may be used. For example, a method of forming gravel piles in the ground is known for ground improvement such as liquefaction countermeasures. In this gravel pile forming method, a space is formed in the ground using an attachment, and gravel is introduced into the formed space to form a gravel pile. The attachment disclosed in Patent Document 1 includes a cylindrical portion in which a gravel introduction hole is formed. The cylindrical portion is connected to a drive device of the ground improvement machine. When the drive device generates a rotational driving force, the cylindrical portion is inserted into the ground while excavating the ground by the rotational driving force. Gravel is introduced into the space formed by excavating the ground through the gravel introduction hole provided in the cylindrical portion. Then, when the gravel pile is formed, the cylindrical portion is pulled out from the ground.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of attachment, the cylindrical part is inserted into the ground and then pulled out from the ground. Therefore, over time, the surface of the cylindrical part wears out, and when the wear progresses, it becomes necessary to replace the cylindrical part. Here, when excavating the ground, it is inserted into the ground from the tip of the cylindrical part, and the cylindrical part inserted into the ground is pulled out from the ground side of the base end. For this reason, the tip side of the cylindrical part wears the most, and it does not wear toward the base end side. In the conventional attachment, even if only the tip side of the cylindrical part is worn, it is necessary to replace the entire cylindrical part, which has the problem of high maintenance costs. This specification discloses a technique capable of reducing the maintenance costs generated by the wear of the cylindrical part.

Means for Solving the Problems

[0005] The attachment disclosed in this specification is an attachment mounted on a construction machine, and is connected to a drive device that generates a rotational driving force of the construction machine, and includes a cylindrical part that excavates the ground by the rotational driving force to form a space. The cylindrical part includes a plurality of cylindrical portions and one or more connecting mechanisms that separably connect the axially adjacent cylindrical portions. At least one of the one or more connecting mechanisms is provided on the inner peripheral surfaces of the two cylindrical portions that the connecting mechanism connects.

[0006] In the above attachment, a plurality of cylindrical portions are axially connected to form the cylindrical part. Therefore, when the cylindrical part is partially worn due to use, only the worn cylindrical portion needs to be replaced, and it is not necessary to replace the non-worn cylindrical portions. As a result, the maintenance costs generated by the wear of the cylindrical part can be reduced. Also, even if the cylindrical part is configured by axially connecting a plurality of cylindrical portions, at least one of the one or more connecting mechanisms is provided on the inner peripheral surface of the cylindrical portion. For this reason, when the cylindrical part is inserted into the ground and when the cylindrical part is pulled out from the ground, it is possible to suppress the connecting mechanism from becoming an obstacle.

[0007] The present specification also discloses a crushed stone pile forming device provided with the above attachment. That is, the crushed stone pile forming device disclosed in the present specification includes the above attachment and a driving device that generates a rotational driving force to drive the attachment. According to this crushed stone pile forming device, the maintenance cost caused by the wear of the cylindrical portion can be reduced.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

DETAILED DESCRIPTION OF THE INVENTION

[0009] (Feature 1) In the attachment disclosed in this specification, the attachment may be an attachment for forming a crushed stone pile by being inserted into the ground to form a space and charging crushed stone into the space. In this case, at least one of the plurality of cylindrical portions may be formed with a crushed stone charging hole.

[0010] (Feature 2) In the attachment disclosed in this specification, a coupling mechanism is formed on the inner peripheral surface, and in the cylindrical portion where the crushed stone charging hole is formed, a crushed stone charging hole may be formed in the vicinity of the coupling mechanism. According to such a configuration, the cylindrical portions can be coupled using the crushed stone charging hole.

[0011] (Feature 3) In the attachment disclosed in this specification, the attachment may be an attachment for forming a crushed stone pile by being inserted into the ground to form a space and charging crushed stone into the space. A crushed stone charging hole may be formed along the axial direction on the side surface of the cylindrical portion. The attachment may be attached to the cylindrical portion and further include a door for opening and closing the crushed stone charging hole. At least a part of the plurality of cylindrical portions may include a crushed stone charging hole portion formed along the axial direction on its side surface. The crushed stone charging hole may be constituted by the crushed stone charging hole portions formed in at least a part of the plurality of cylindrical portions. According to such a configuration, one crushed stone charging hole can be formed by the crushed stone charging hole portions formed in a part of the plurality of cylindrical portions.

[0012] (Feature 4) In the attachment disclosed in this specification, a crushed stone inlet hole portion may be formed on the side surfaces of at least two adjacent cylindrical portions among the plurality of cylindrical portions. The crushed stone inlet hole may be constituted by the crushed stone inlet hole portions formed in at least two adjacent cylindrical portions. According to such a configuration, by forming the crushed stone inlet hole portions in a plurality of adjacent cylindrical portions, a crushed stone inlet hole having a desired length extending in the axial direction can be constituted.

[0013] (Feature 5) In the attachment disclosed in this specification, at least one of the plurality of connecting mechanisms is provided on the inner peripheral surface of one of the two cylindrical portions that the connecting mechanism connects, and a first inner flange that protrudes from the inner peripheral surface toward the axis of the cylindrical portion, and is provided on the inner peripheral surface of the other of the two cylindrical portions that the connecting mechanism connects, and a second inner flange that protrudes from the inner peripheral surface toward the axis of the cylindrical portion, may be provided. By coupling the first inner flange and the second inner flange, the two cylindrical portions may be connected. According to such a configuration, while the connecting mechanism has a simple configuration, the two cylindrical portions can be firmly connected.

[0014] (Feature 6) In the attachment disclosed in this specification, the first inner flange may be formed in at least a part of the circumferential direction of the cylindrical portion on which the first inner flange is provided. The second inner flange may be formed in at least a part of the circumferential direction of the cylindrical portion on which the second inner flange is provided.

[0015] (Feature 7) In the attachment disclosed in this specification, a plurality of first through holes may be formed in the first inner flange at intervals in the circumferential direction. A second through hole may be formed at a position corresponding to the first through hole of the second inner flange. At least one of the plurality of connecting mechanisms may include a plurality of fastening members inserted into the first through holes of the first inner flange and the second through holes of the second inner flange corresponding to the first through holes. According to such a configuration, the cylindrical portions adjacent in the axial direction are connected at a plurality of locations in the circumferential direction. Therefore, the cylindrical portions can be firmly connected to each other.

[0016] (Feature 8) In the attachment disclosed in this specification, one or more positioning recesses may be further formed in the first inner flange. A positioning protrusion may be further formed at a position corresponding to the positioning recess of the second inner flange. When the first inner flange and the second inner flange are coupled, the positioning protrusion may be received in the positioning recess. According to such a configuration, when connecting the cylindrical portions in the axial direction, circumferential alignment can be correctly performed.

[0017] (Feature 9) In the attachment disclosed in this specification, in the cylindrical portion where the coupling mechanism is formed on the inner peripheral surface, a crushed stone input hole portion may be formed up to the vicinity of the coupling mechanism. According to such a configuration, an operator can insert a hand into the cylindrical portion through the crushed stone input hole portion and perform an operation of connecting the cylindrical portions. Therefore, the operation of connecting the cylindrical portions can be easily performed.

Embodiment

[0018] Hereinafter, the crushed stone pile forming apparatus 100 according to this embodiment will be described. As shown in FIG. 1, the crushed stone pile forming apparatus 100 includes a ground improvement machine 40 as a construction machine and an attachment 10 attached to the ground improvement machine 40. As shown in FIG. 1, the ground improvement machine 40 includes a ground improvement machine main body structure 1, a cabin 7 as an operator's cab, a crawler 6 which is an endless track capable of moving on uneven ground with low ground pressure, and an outrigger 5 that suppresses the rocking of the ground improvement machine 40 during construction.

[0019] The ground improvement machine 40 further includes, as a configuration for operating the attachment 10, a drive device 11 that supplies a rotational driving force to the attachment 10 via the motor output shaft 27, a leader 4 having a lifting guide rail 9, a lifting table 17 that moves the drive device 11 and the attachment 10 up and down along the lifting guide rail 9, a leader mounting base 2 for supporting the leader 4, a hydraulic cylinder 3 for operating the inclination of the leader 4, and an extension leg column 8 integrally formed with the leader 4 at the lower end of the leader 4.

[0020] As shown in FIGS. 1 and 2, the attachment 10 includes a cylindrical portion 12 provided with fins 13, a spiral portion 14, a surrounding frame 30 for preventing the cylindrical portion 12 from swaying, a hanger stay 18 attached to the lifting table 17, a top cover case 16, a crushed stone feeding device 32, a support plate 37 for supporting the surrounding frame 30, a support arm 39 for supporting the crushed stone feeding device 32, and a construction management device 41 for managing the construction state by the attachment 10.

[0021] The cylindrical portion 12 is a cylindrical member and includes a plurality of cylindrical parts 12A and 12B. Specifically, the cylindrical portion 12 of the present embodiment is configured by axially connecting two cylindrical parts 12A and 12B. Note that the number of cylindrical parts 12A and 12B may be three or more. The cylindrical part 12A located on the upper side in FIGS. 1 and 2 is the cylindrical part 12A on the gearbox side. The cylindrical part 12B located on the lower side in FIGS. 1 and 2 is the cylindrical part 12B on the head side. These two cylindrical parts 12A and 12B have the same outer diameter. Therefore, when the two cylindrical parts 12A and 12B are axially connected, their outer peripheral surfaces 12b are in a flush state without a step. The cylindrical portion 12 is provided with a mechanism for separably connecting two axially adjacent cylindrical parts 12A and 12B. This mechanism will be described in detail later.

[0022] The cylindrical portions 12A and 12B are provided with crushed stone inlet holes 15A and 15B formed along the axial direction on their side surfaces. Since the circumferential positions where the two crushed stone inlet hole portions 15A and 15B are formed are the same position, one crushed stone inlet hole 15 is constituted by the two crushed stone inlet hole portions 15A and 15B. The crushed stone inlet hole 15 extends in the axial direction of the cylindrical portion 12 and is closed by an opening / closing door 20 made of elastic deformable rubber or resin. Specifically, as shown in FIGS. 3 and 4, the crushed stone inlet hole 15 is formed in the mounting plate 28, and the opening / closing door 20 is fixed to the mounting plate 28. The mounting plate 28 includes a mounting portion 28a provided at one edge (the edge extending in the z direction) of the crushed stone inlet hole 15 and a receiving portion 28b provided at the other edge (the edge extending in the z direction) of the crushed stone inlet hole 15. The opening / closing door 20 closes the crushed stone inlet hole 15 by contacting the mounting portion 28a and the receiving portion 28b. The mounting portion 28a is located on the -X direction side in FIG. 3, and the receiving portion 28b is located on the +X direction side in FIG. 3. When the crushed stone feeding device 32 is arranged at a position facing the crushed stone inlet hole 15, the mounting portion 28a is located on the clockwise side (the forward rotation direction side described later) with respect to the crushed stone feeding device 32, and the receiving portion 28b is located on the counterclockwise side (the reverse rotation direction side described later).

[0023] The crushed stone feeding device 32 includes a hopper portion 33 and a chute portion 34 arranged below the hopper portion 33. The crushed stone inlet hole 15 is closed by the opening / closing door 20 when the attachment 10 excavates the ground. Thereby, it is possible to prevent earth and sand from entering the cylindrical portion 12 from the crushed stone inlet hole 15. Further, when the crushed stone is fed into the cylindrical portion 12, the opening / closing door 20 is opened (see FIG. 4). Thereby, the crushed stone fed into the crushed stone feeding device 32 can be fed into the cylindrical portion 12 from the crushed stone inlet hole 15. Further, since the crushed stone inlet hole 15 is provided as a long hole along the axial direction, the crushed stone can be fed into the cylindrical portion 12 without changing the crushed stone feeding position even when the cylindrical portion 12 rises.

[0024] As shown in FIGS. 1 and 2, the spiral part 14 is located at the tip of the cylindrical part 12 and is integrally formed with the core rod 22 (shown in FIGS. 3 and 4) and the rotary input shaft 31. The rotary input shaft 31 is connected to the motor output shaft 27 of the driving device 11. The rotary input shaft 31 rotates according to the rotational driving force of the motor output shaft 27, and transmits the rotational driving force to the spiral part 14 via the core rod 22 integrally coupled thereto. A cutting blade is provided at the tip of the spiral part 14. The cutting blade is formed in a spiral shape whose diameter increases toward the tip of the spiral part 14. Substantially the entire cutting blade is disposed within the cylindrical part 12, and only a part of the tip of the cutting blade protrudes from the tip of the cylindrical part 12.

[0025] The core rod 22 (shown in FIG. 3) is rotatably coupled to the cylindrical part 12 at a position not shown and shares the rotation axis with the cylindrical part 12. The cylindrical part 12 has spiral fins 13 around it. The fins 13 have a spiral shape in the same direction as the spiral of the spiral part 14 (i.e., the cutting blade). That is, when excavating, the cylindrical part 12 and the spiral part 14 rotate in the same direction. As a result, the excavated soil and sand generated by the excavation of the spiral part 14 are transported to the ground surface by the fins 13.

[0026] The top cover case 16 is attached to the rear end of the cylindrical part 12 and is integrated with the cylindrical part 12. The core rod 22 penetrates the upper surface of the top cover case 16 and is rotatably supported by the top cover case 16. For this reason, even when the core rod 22 is rotationally driven, the cylindrical part 12 is kept in a free state without rotating together with the core rod 22.

[0027] Attachment 10 further includes a rotational driving force transmission part and an anti-reverse part (not shown). The rotational driving force transmission part is a one-way clutch mechanism. When driving the spiral part 14 in the rotational direction during excavation, it automatically rotates the spiral part 14 and the cylindrical part 12 integrally. Thereby, the earth and sand excavated by the spiral part 14 as described above can be discharged onto the ground by the fins 13 provided on the cylindrical part 12. On the other hand, when driving the spiral part 14 in the direction opposite to the rotational direction during excavation, the rotational driving force transmission part applies pressure to the crushed stones by rotating the spiral part 14 in the reverse direction, and cuts off the power transmission from the spiral part 14 to the cylindrical part 12 to stop the rotation of the cylindrical part 12. When driving the spiral part 14 in the direction opposite to the rotational direction during excavation, the anti-reverse part restricts the rotation of the cylindrical part 12 so that the cylindrical part 12 that has stopped rotating does not rotate in either the rotational direction or the reverse direction during excavation. Hereinafter, the direction in which the cylindrical part 12 and the spiral part 14 rotate in the same direction, that is, the rotational direction during excavation, is referred to as the "forward rotation direction", and the direction of rotation opposite to the rotational direction during excavation, that is, the rotational direction in which pressure is applied to the crushed stones by the spiral part 14, may be referred to as the "reverse direction". Also, the rotation in the forward rotation direction is described as right rotation (clockwise), and the rotation in the reverse direction is described as left rotation (counterclockwise).

[0028] Here, based on FIGS. 5 to 8, the configuration of the connection mechanism 61 provided in the cylindrical part 12 will be described in detail. The connection mechanism 61 is for separably connecting two axially adjacent cylindrical portions 12A and 12B, and is provided on the inner peripheral surfaces 12c of the two cylindrical portions 12A and 12B that the connection mechanism 61 connects. Specifically, as shown in FIGS. 5, 7, and 8, one connection mechanism 61 is provided by being welded to the inner peripheral surface 12c at the lower end of the upper cylindrical portion 12A. The other connection mechanism 61 is provided by being welded to the inner peripheral surface 12c at the upper end of the lower cylindrical portion 12B, as shown in FIGS. 6, 7, and 8.

[0029] The connecting mechanism 61 belonging to the upper cylindrical portion 12A includes a first inner flange 62. The first inner flange 62 protrudes from the inner peripheral surface 12c of the upper cylindrical portion 12A toward the axis of the cylindrical portion 12A. The connecting mechanism 61 belonging to the lower cylindrical portion 12B to which the upper cylindrical portion 12A is connected includes a second inner flange 63. The second inner flange 63 protrudes from the inner peripheral surface 12c of the lower cylindrical portion 12B toward the axis of the cylindrical portion 12B. The lower surface of the first inner flange 62 and the upper surface of the second inner flange 63 are arranged to face each other. The first inner flange 62 and the second inner flange 63 are joined in a state of surface contact with each other, and as a result, the two cylindrical portions 12A and 12B are connected. That is, although the connecting mechanism 61 of the present embodiment has a relatively simple configuration, it is possible to firmly connect the two cylindrical portions 12A and 12B.

[0030] As shown in FIG. 5, the first inner flange 62 is a metal plate member formed in a substantially D shape in plan view. The first inner flange 62 has a curved portion 62a and a straight portion 62c. A pair of wide portions 62b are formed at positions facing each other across the axis of the cylindrical portion 12A in the curved portion 62a. Also, wide portions 62b protruding inward are formed at the center of the curved portion 62a and at the connection portion between the curved portion 62a and the straight portion 62c, respectively. The outer peripheral edge of the curved portion 62a of the first inner flange 62 is fixed in contact with the inner peripheral surface 12c of the upper cylindrical portion 12A. The straight portion 62b of the first inner flange 62 is arranged corresponding to the position where the opening / closing door 20 is located. That is, the curved portion 62a of the first inner flange 62 is formed over substantially the entire circumferential direction of the upper cylindrical portion 12A where the first inner flange 62 is provided. A notch portion 62d is formed at the center of the straight portion 62c. The notch portion 62d provides a relatively wide clearance between the core rod 22 and the first inner flange 62. That is, by forming the notch portion 62d at the portion where the distance between the core rod 22 and the first inner flange 62 is the shortest (the center of the straight portion 62b), sufficient clearance is ensured between the core rod 22 and the first inner flange 62.

[0031] A plurality of upper through holes 64b (an example of the first through hole) are formed in the first inner flange 62 at intervals in the circumferential direction. Specifically, one upper through hole 64b is formed in the wide portion 62b at the center of the curved portion 62a, and upper through holes 64b are respectively formed in the two wide portions 62b at the connection portions between the curved portion 62a and the straight portion 62c. That is, the upper through holes 64b are respectively formed at three locations: the center and both ends of the curved portion 62a. Further, a pair of positioning recesses 64a are formed in the first inner flange 62. Specifically, the positioning recesses 64a are formed in a pair of wide portions 62b facing each other across the axis of the cylindrical portion 12A. The positioning recess 64a is a recess formed on the lower surface of the first inner flange 62 and functions as a housing hole for housing a positioning projection 65a described later. That is, the positioning recess 64a is formed as a space that is recessed upward from the lower surface of the first inner flange 62.

[0032] As shown in FIG. 6, the second inner flange 63 is configured in the same manner as the first inner flange 62 and is a metal plate member formed in a substantially D shape in plan view. The second inner flange 63 also has a curved portion 63a and a straight portion 63c. A pair of wide portions 63b are formed in the curved portion 63a at positions facing each other across the axis of the cylindrical portion 12B. Further, wide portions 63b are also formed at the center of the curved portion 63a and at the connection portions between the curved portion 63a and the straight portion 63c. The outer peripheral edge of the curved portion 63a of the second inner flange 63 is fixed so as to be in contact with the inner peripheral surface 12c of the lower cylindrical portion 12B. The straight portion 63c of the second inner flange 63 is arranged corresponding to the position where the opening and closing door 20 is located. A notch 63d is also formed at the center of the straight portion 63c. Thereby, sufficient clearance is also ensured between the core rod 22 and the second inner flange 63.

[0033] Similar to the first inner flange 62, a plurality of lower through holes 65b (an example of the second through holes) are formed in the second inner flange 63 at intervals in the circumferential direction. The plurality of lower through holes 65b have the same configuration as the upper through holes 64b and are formed at positions corresponding to the upper through holes 64b, respectively. Further, in the second inner flange 63, positioning protrusions 65a are formed on a pair of wide portions 63b facing each other across the axis of the cylindrical portion 12B. The positioning protrusions 65a are formed at positions corresponding to the positioning recesses 64a and protrude upward from the upper surface of the second inner flange 63. The shape of the positioning protrusions 65a corresponds to the shape of the positioning recesses 64a. That is, the positioning protrusions 65a are formed in a shape that can be accommodated in the positioning recesses 64a.

[0034] As shown in FIGS. 7 and 8, the two connecting mechanisms 61 arranged vertically include a plurality of fastening members (66a, 66b) for connecting the axially adjacent cylindrical portions 12A and 12B to each other at a plurality of locations in the circumferential direction. The plurality of fastening members (66a, 66b) are inserted into the upper through holes 64b of the first inner flange 62 and the lower through holes 65b of the second inner flange 63 corresponding to the upper through holes 64b.

[0035] When connecting the cylindrical portions 12A and 12B, the circumferential alignment of the first inner flange 62 and the second inner flange 63 is performed so that the positioning protrusions 65a are received in the positioning recesses 64a. Thereby, the cylindrical portions 12A and 12B are properly connected, and the upper through holes 64b of the first inner flange 62 and the lower through holes 65b of the second inner flange 63 are in a facing state. As described above, only a pair of the positioning protrusions 65a and the positioning recesses 64a are arranged at positions facing each other across the axis of the cylindrical portions 12A and 12B. Thereby, the circumferential alignment operation of the cylindrical portions 12A and 12B can be easily performed. Further, the positioning recesses 64a are formed in the first inner flange 62, and the upper ends thereof are closed. Thereby, the entry of earth and sand or the like into the positioning recesses 64a is suppressed.

[0036] As described above, in a state where the cylindrical portions 12A and 12B are aligned in the circumferential direction, the plurality of fastening members (66a, 66b) are inserted into the upper through-hole 64b and the lower through-hole 65b. In this embodiment, as the plurality of fastening members (66a, 66b), a metal fastening member composed of a bolt 66b and a nut 66a is used. These bolts 66b are inserted, for example, from the lower opening side of the lower through-hole 65b. The upper half portions of these bolts 66b have male threads and protrude from the upper surface of the second inner flange 63. The upper half portions of these bolts 66b can further be inserted through the upper through-hole 64b. The tip ends of these bolts protrude from the upper surface of the first inner flange 62, and a nut 66a is screwed onto the protruding portions. Note that a rotation prevention function may be added to the fastening member composed of these bolts 66b and nut 66a by means of a split pin or the like. By adding a rotation prevention function to the fastening member, the cylindrical portions 12A and 12B can be firmly connected, and it is possible to suppress a situation where the two become loose when forming the crushed stone pile.

[0037] Next, the operation of the crushed stone pile forming device 100 when the crushed stone pile forming device 100 forms a crushed stone pile will be described. First, the alignment of the attachment 10 is performed. The alignment of the attachment 10 is performed by adjusting the position and direction of the ground improvement machine 40 by driving the crawler 6. After adjusting the position and direction of the ground improvement machine 40, the ground improvement machine 40 may be fixed to the ground by the outrigger 5. Thereby, it is possible to suppress the rocking and displacement of the ground improvement machine 40 during construction.

[0038] Next, insert the attachment 10 into the ground to excavate the ground. Specifically, after fixing the ground improvement machine 40 to the ground surface, lower the attachment 10 while driving the drive device 11. At this time, the drive device 11 is driven to generate a rotational driving force in the forward rotation direction. As described above, when the drive device 11 generates a rotational driving force in the forward rotation direction, the spiral part 14 and the cylindrical part 12 rotate in the forward rotation direction by the rotational driving force transmission part. As a result, the attachment 10 is inserted into the ground and excavated. The earth and sand discharged by the excavation of the ground are carried to the outer periphery of the cylindrical part 12 and discharged to the ground surface by the fins 13. When the attachment 10 reaches a predetermined depth, stop the driving of the forward rotation of the drive device 11 and end the excavation.

[0039] Next, raise the attachment 10 to form a crushed stone pile in the ground. The formation of the crushed stone pile is performed according to the following procedure. First, as shown in FIG. 4, with the opening / closing door 20 open, put crushed stone into the crushed stone feeding device 32. The crushed stone put into the crushed stone feeding device 32 is put into the cylindrical part 12 through the crushed stone feeding hole 15. Next, drive the drive device 11 so that a rotational driving force in the reverse rotation direction is generated. Then, the spiral part 14 rotates in the reverse rotation direction and discharges the crushed stone put into the cylindrical part 12 to the outside of the cylindrical part 12 while pressing it from the spiral part 14. As a result, the attachment 10 is pushed out of the ground and a crushed stone pile is formed in the space formed by the cylindrical part 12. As described above, when the drive device 11 generates a rotational driving force in the reverse rotation direction, only the spiral part 14 rotates in the reverse rotation direction by the rotational driving force transmission part, and the cylindrical part 12 does not rotate in either the forward rotation direction or the reverse rotation direction. Therefore, it is possible to avoid the position of the crushed stone feeding hole 15 provided in the cylindrical part 12 from changing in the circumferential direction, and it is possible to put crushed stone into the cylindrical part 12 without adjusting the position of the crushed stone feeding device 32. When the attachment 10 is pushed out to the ground surface, stop the driving of the drive device 11 in the reverse rotation direction and end the formation of the crushed stone pile.

[0040] In this type of attachment 10, the surface of the cylindrical portion 12 wears over time, and when the wear progresses, it becomes necessary to replace the cylindrical portion 12. Here, when excavating the ground to form the crushed stone pile, it is inserted into the ground from the tip of the cylindrical portion 12, and the cylindrical portion 12 inserted into the ground is pulled out from the base end side from the ground. For this reason, the tip side of the cylindrical portion 12 wears the most, and it does not wear toward the base end side. That is, among the cylindrical portion 12, the lower cylindrical portion 12B has a greater degree of wear, and the upper cylindrical portion 12A has a smaller degree of wear. Therefore, when such wear occurs, a maintenance operation of replacing only the worn lower cylindrical portion 12B is performed.

[0041] First, by changing the two connecting mechanisms 61 in the connected state to the unconnected state, the lower cylindrical portion 12B is removed from the upper cylindrical portion 12A. Specifically, the nut 66a that constitutes the plurality of fastening members (66a, 66b) is removed from the bolt 66b, and further the bolt 66b is removed from the upper through hole 64b and the lower through hole 65b. As a result, the two connecting mechanisms 61 become separable, and it becomes possible to remove the lower cylindrical portion 12B from the upper cylindrical portion 12A. In the cylindrical portions 12A and 12B where the connecting mechanism 61 is formed on the inner peripheral surface 12c, the crushed stone inlet hole portions 15A and 15B are formed up to the vicinity of the connecting mechanism 61 in both cases. Therefore, an operator can insert a hand into the cylindrical portion 12 from the crushed stone inlet hole portions 15A and 15B and perform an operation of removing the cylindrical portions 12A and 12B from each other. For this reason, the operation of removing the cylindrical portions 12A and 12B can be easily performed.

[0042] Next, attach the newly prepared lower cylindrical portion 12B to the upper cylindrical portion 12A. Specifically, fit the positioning convex portion 65a into the positioning concave portion 64a, insert the bolt 66b that constitutes the plurality of fastening members (66a, 66b) into the upper through-hole 64b and the lower through-hole 65b, and screw the nut 66a onto the tip side of the bolt 66b. As a result, the two coupling mechanisms 61 are coupled. By connecting the cylindrical portions 12A and 12B adjacent in the axial direction to each other at a plurality of locations in the circumferential direction in this way, the cylindrical portions 12A and 12B are firmly connected. At that time, the circumferential alignment is also correctly performed. As a result of the above-described connection operation, the attachment 10 becomes reusable again.

[0043] As described in detail above, in the attachment 10 of the present embodiment, the two cylindrical portions 12A and 12B are connected in the axial direction to form the cylindrical portion 12. Therefore, when the cylindrical portion 12 is partially worn due to use, only the worn cylindrical portion (here, the lower cylindrical portion 12B) needs to be replaced, and the unworn cylindrical portion (here, the upper cylindrical portion 12A) does not need to be replaced. Thereby, the maintenance cost generated due to the wear of the cylindrical portion 12 can be reduced. Further, even if the cylindrical portion 12 is configured by connecting the two cylindrical portions 12A and 12B in the axial direction, the coupling mechanisms 61 respectively provided on the inner peripheral surfaces 12c of the cylindrical portions 12A and 12B. That is, none of the coupling mechanisms 61 are exposed on the outer peripheral surface 12b of the cylindrical portions 12A and 12B. Therefore, when the cylindrical portion 12 is inserted into the ground and when the cylindrical portion 12 is pulled out from the ground, it is possible to suppress the coupling mechanism 61 from becoming an obstacle.

[0044] In addition, in this embodiment, the outer diameters of the two cylindrical portions 12A and 12B are equal, and their outer peripheral surfaces 12b are configured to be flush with each other when connected, but it is not limited thereto. The connecting mechanism 61 may be configured such that one cylindrical portion fits into the other cylindrical portion. Further, the connecting mechanism 61 may be configured such that an engaging piece formed on one cylindrical portion engages with a groove or the like on the inner peripheral surface of the other cylindrical portion. Furthermore, for example, when there are three or more cylindrical portions, the lowermost cylindrical portion may be formed to have a smaller diameter than the other cylindrical portions. That is, in order to reduce the diameter of the tip portion of the cylindrical portion 12, a step may be provided on the outer peripheral surface of the cylindrical portion intentionally. Also, when the cylindrical portion is composed of three or more cylindrical portions, it is only necessary that the connecting mechanism 61 disclosed in this specification is formed on the inner peripheral surface 12c only in a part of these plurality of connecting mechanisms, and for some of the connecting mechanisms 61, a connecting mechanism may be formed on the outer peripheral surface 12b.

[0045] Also, in this embodiment, the first inner flange 62 and the second inner flange 63 are formed over substantially the entire circumferential direction of the cylindrical portions 12A and 12B, but they may be formed in a part of the circumferential direction.

[0046] Also, the positioning convex portion 65a and the positioning concave portion 64a are not limited to the configuration of this embodiment. For example, a groove for positioning (e.g., a rectangular key groove) may be formed, and the circumferential alignment of the cylindrical portions 12A and 12B may be performed thereby.

[0047] Also, in this embodiment, bolts and nuts are used as the fastening members (66a, 66b), but other fastening members may be used. For example, a female thread may be formed in a through-hole of one inner flange (e.g., the upper through-hole 64b of the first inner flange 62), and a bolt may be screwed into the through-hole of the inner flange.

[0048] In addition, in this embodiment, as a method of forming a crushed stone pile by throwing crushed stones into a space formed in the ground, tightening was performed by reverse rotation of the screw of the attachment 10, but it is not limited to such an example. The technology disclosed in this specification can also be adopted in a method of forming a crushed stone pile that does not use tightening by reverse rotation of the screw of the attachment 10.

[0049] Further, in this embodiment, an example is shown in which an attachment is attached to the leader of the ground improvement machine. However, the technology disclosed in this specification is not limited to such an example, and the attachment disclosed in this specification can be attached to various construction machines. For example, as shown in FIG. 9, an attachment 144 may be attached to a gun hoe 140 (an example of a construction machine). In this case, the attachment 144 is connected to the tip of the arm 142 of the gun hoe 140 (specifically, a drive device (motor) provided at the arm tip). When the drive device at the arm tip operates, the attachment 144 rotates and can excavate the ground.

[0050] In addition, in this embodiment, a crushed stone input hole 15 extending in the axial direction is formed on the side surface of the cylindrical portion 12, and crushed stones are input into the cylindrical portion 12 from the crushed stone input hole 15. However, the technology disclosed in this specification is not limited to such an example. For example, as shown in FIG. 10, a crushed stone input hole 74 may be formed near the upper end of the cylindrical portions (70, 72), and crushed stones may be input into the cylindrical portions (70, 72) from the crushed stone input hole 74. In this case, the crushed stone input hole 74 is formed only in the upper cylindrical portion 70, and no crushed stone input hole is formed in the lower cylindrical portion 72. Further, as is apparent from FIG. 10, the axial length of the lower cylindrical portion 72 of the lower mold is shorter than the axial length of the upper cylindrical portion 70 of the upper mold. As a result, the structure of the lower end portion of the cylindrical portions (70, 72) (i.e., the lower cylindrical portion 72) that is easily worn becomes simpler and its axial length becomes shorter, so that the maintenance cost can be further reduced. In FIG. 10, the illustration of the spiral portion (corresponding to the spiral portion 14 of the above-described embodiment) is omitted.

[0051] When using the attachment shown in Fig. 10, the connection between the upper cylindrical portion 70 and the lower die cylindrical portion 72 can be made from the lower end opening of the lower cylindrical portion 72. For example, as shown in Fig. 11, bolts 80 are fixed to the inner flange 76 of the upper cylindrical portion 70, and through holes through which the tips of the bolts 80 are inserted are formed in the inner flange 78 of the lower cylindrical portion 72. Then, by screwing a nut 82 onto the tip of the bolt 80 using a jig 84, the upper cylindrical portion 70 and the lower cylindrical portion 72 are connected. Note that the circumferential alignment of the upper cylindrical portion 70 and the lower cylindrical portion 72 can be performed by positioning convex portions (not shown) and positioning concave portions (not shown) formed on the inner flanges 76 and 78, similar to the above-described embodiment. Alternatively, without forming positioning convex portions and positioning concave portions on the inner flange, as shown in Fig. 12, a stay 88 may be formed on the outer peripheral surface of the upper cylindrical portion 86, and a groove (not shown) that engages with the stay 88 may be formed in the lower cylindrical portion 90. In this case, since the circumferential alignment of the upper cylindrical portion 86 and the lower cylindrical portion 90 can be visually performed, the circumferential alignment of the two can be performed more easily.

[0052] Also, in this embodiment, the attachment 10 was of the type that discharges the excavated earth and sand to the ground surface (so-called earth discharge type), but it is not limited to such an example. The technology disclosed in this specification can also be adopted, for example, in an attachment of the non-earth discharge type that does not discharge the excavated earth and sand to the ground surface.

[0053] As described above, specific examples of the technology disclosed in this specification have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Also, the technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

Explanation of Reference Numerals

[0054] 10 Attachment 11 Driving Device 12 Cylindrical part 12A Cylindrical portion 12B Cylindrical portion 12c Inner peripheral surface 15 Crushed stone inlet 15A Crushed stone inlet portion 15B Crushed stone inlet portion 20 Opening / closing door as a door 61 Connecting mechanism 62 First inner flange 63 Second inner flange 64a Positioning recess 64b Upper through-hole 65a Positioning protrusion 65b Lower through-hole 66a Nut 66b Bolt 100 Crushed stone pile forming device

Claims

1. An attachment to be mounted on a construction machine, connected to a drive device that generates a rotational driving force of the construction machine, and comprising a cylindrical portion that excavates the ground by the rotational driving force to form a space, the cylindrical portion comprising a plurality of cylindrical parts and one or more connecting mechanisms that separably connect the axially adjacent cylindrical parts, the attachment, wherein at least one of the one or more connecting mechanisms is provided on the inner peripheral surfaces of two cylindrical parts that the connecting mechanism connects.

2. The attachment is an attachment for forming a crushed stone pile, which is inserted into the ground to form a space and into which crushed stone is introduced to form a crushed stone pile, the attachment according to claim 1, wherein at least one of the plurality of cylindrical parts is formed with a crushed stone introduction hole.

3. In the cylindrical part in which the connecting mechanism is formed on the inner peripheral surface and the crushed stone introduction hole is formed, the crushed stone introduction hole is formed in the vicinity of the connecting mechanism, the attachment according to claim 2.

4. The attachment is an attachment for forming a crushed stone pile, which is inserted into the ground to form a space and into which crushed stone is introduced to form a crushed stone pile, wherein a crushed stone introduction hole is formed along the axial direction on the side surface of the cylindrical portion, the attachment further comprising a door that is attached to the cylindrical portion and opens and closes the crushed stone introduction hole, at least a part of the plurality of cylindrical parts comprising a crushed stone introduction hole portion formed along the axial direction on the side surface thereof, the attachment according to claim 1, wherein the crushed stone introduction hole is constituted by the crushed stone introduction hole portion formed in at least a part of the plurality of cylindrical parts.

5. The crushed stone introduction hole portion is formed on the side surfaces of at least two adjacent cylindrical parts among the plurality of cylindrical parts, the attachment according to claim 4, wherein the crushed stone introduction hole is constituted by the crushed stone introduction hole portion formed in the at least two adjacent cylindrical parts.

6. An attachment according to any one of claims 1 to 5, and a drive device that generates a rotational driving force in a forward rotation direction and a reverse rotation direction to drive the attachment, a crushed stone pile forming device.

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