JP6549265B1 - Ground improvement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground improvement device for a projecting piece provided on a horizontal cylindrical body rotatably fitted on a horizontal shaft body provided on an excavation shaft and provided for vertical rotation of three-dimensional agitation of excavated soil. Provided is a protruding piece mounting structure capable of preventing breakage and bending deformation of the protruding piece and simplifying and speeding up the replacement work. An outer peripheral surface of a horizontal cylindrical body 12 is provided with a concave portion 22 capable of accommodating a shaft portion forming a base end portion of a protruding piece 13, and a base end 23 having a larger diameter than an outer diameter of the shaft portion. The piece attachment body 21 is welded along the outer peripheral edge of the base end face with the base end face of the protruding piece attachment body 21 in a butted state. The shaft portion formed by the base end portion of the projecting piece 13 is accommodated in the recess 22 of the projecting piece mounting body 21, and the projecting piece 13 is not welded, for example, by bolting or the like. A structure for detachably attaching to the recess 22 is provided. [Selection] Figure 4

Description

  TECHNICAL FIELD The present invention relates to a ground improvement device, and more particularly, in civil engineering, foundation work of architecture, etc., while digging soft ground into columns etc., a lime-based or cement-based slurry-like solidifying agent ) To discharge soft soil and mix and agitate the solidifying agent and excavated soil (earth and sand) to solidify the soft ground into columns etc. and improve it to high strength. Ground improvement equipment.

  A ground improvement device of this type is basically provided with a digging blade provided near the tip of a rotating digging shaft and one or more stirring blades provided above the digging blade. In this device, the tip of the rotating drilling axis is pushed into the ground, the ground is excavated with the drilling blade, and while the earth and sand excavated with the stirring blade is stirred, the upper stirring blade and from near the tip of the drilling shaft The solidifying agent to be discharged and the excavated soil are mixed and stirred. In this case, since the excavated soil is only mixed and stirred in a so-called horizontal direction (lateral direction) around the drilling axis, there is a problem in mixing and stirring properties, so recently such a horizontal In addition to mixing and stirring around, a ground improvement device has been proposed that can mix and stir excavated soil around a horizontal shaft provided to project laterally from the excavating axis, that is, longitudinally. (See, for example, Patent Document 1 and Patent Document 2).

  The ground improvement device described in Patent Document 1 has the following configuration. That is, a rotating drilling shaft, a drilling blade provided in the vicinity of the tip end thereof, and an outer fitting that is freely rotatable relative to the drilling shaft about the axis above the drilling blade A support (annular body), a horizontal shaft fixed to the support so as to protrude laterally, and an outer shaft which is rotatable relative to the horizontal shaft about its horizontal axis. A horizontal cylindrical body, and three or more projecting pieces fixed on the outer peripheral surface of the horizontal cylindrical body at an angle interval around the horizontal axis of the horizontal shaft and fixed via the shaft portion of the base end; When the drilling shaft rotates and the support and the horizontal shaft do not rotate around the drilling shaft, the projection piece intermittently contacts with the projection piece and the horizontal cylindrical body along the horizontal axis of the horizontal shaft body And an impact unit (rotational drive unit) that rotates (vertically). In this ground improvement device, the lateral shaft has a length such that the tip portion thereof is positioned outward of the circumference described by the tip of the digging blade when the digging blade rotates as viewed from the axial direction of the digging axis The horizontal cylindrical body is rotatable about the axis (horizontal axis) of the horizontal shaft inward of its circumference.

  In the ground improvement device described in Patent Document 1, while rotating the drilling axis with the ground (ground surface) as the drilling start plane, the tip (lower end) thereof is pushed into the ground and lowered, and digging is advanced by the drilling blade, The tip of the horizontal shaft strikes the outer periphery (outside) of the periphery of the excavated diameter on the ground surface (the circumference of the tip of which the drilling blade rotates and the tip draws), and as the horizontal shaft gets into the excavated soil, The shaft becomes constrained by the unearthed hard soil at its tip and does not rotate about the axis of the drilling axis. Thereby, the earth and sand (earth mass) rotated in the rotational direction by the digging blade is prevented by the horizontal axis from rotating around the axis of the drilling axis, and is mixed and stirred around the drilling axis. In addition, for example, an impact unit (rotational drive unit) provided on the drilling shaft, which rotates with the drilling shaft, intermittently contacts a protruding piece of a cylindrical body (horizontal cylindrical body) provided on the horizontal shaft, The projecting piece and the cylindrical body (horizontal cylindrical body) are rotated about the axis of the horizontal shaft. Thereby, the excavated soil is mixed and stirred also around the axis of the horizontal shaft (longitudinal rotation) by the projecting pieces (mixing and stirring means) provided on the horizontal cylindrical body, and so to say three-dimensionally mixed and stirred Therefore, the improvement body to be consolidated thereafter becomes uniform with uniform consolidation strength as a whole.

  In the above ground improvement device, the horizontal shaft has a length which is located outward of the circumference of the tip of the cutting blade which is rotated by the turning of the cutting blade, and the tip portion is not excavated. Restraining by the soil is to stop the rotation of the horizontal axis about the drilling axis, but the means for stopping the rotation of the horizontal axis is not limited to this. For example, the horizontal shaft may be embodied as having a length whose tip is located inward of the circumference described by the tip of the digging wing. That is, an annular body provided with a horizontal shaft and externally fitted to the excavating shaft is extended upward to form a cylindrical body (outer pipe extending vertically). For example, this cylindrical body is excavated above it In order to impart rotation to the shaft, it may be fixed to a heavy machine mount (head of an auger) to which a motor connected to the upper end is attached (head of an auger) so that the cylindrical body is not rotated (FIG. 1 of Patent Document 2) -See Figure 5). In addition, while the horizontal shaft rotates with the digging shaft, the striking portion (protruding portion) is freely rotatable relative to the digging shaft, and this striking portion is stopped when the digging shaft rotates, the digging shaft A horizontal shaft by applying a projecting piece (stirring body) provided on a horizontal cylindrical body externally fitted to the horizontal shaft rotating with the shaft to the striking portion (rotation preventing wing) at rest Can be vertically rotated while rotating (laterally turning) around the digging axis (see FIGS. 6 to 8 of Patent Document 2).

  By the way, in the ground improvement device which can obtain the above-mentioned conventional three-dimensional mixing and stirring (the drilling and stirring device in Patent Document 2), the projecting piece is rotated about the axis of the horizontal shaft (about the horizontal axis). On the outer peripheral surface of the provided steel cylindrical body (horizontal cylindrical body), it is provided so as to extend outward at equal angular intervals (radial arrangement) when viewed from the horizontal axis direction, for example, but this protrusion Fixing of the piece to the outer peripheral surface of the horizontal cylindrical body is usually a steel such as a protruding piece, a rod material such as a round bar, and an axis which is a proximal end of the protruding piece for ease of manufacture and maintenance. The end face of the portion is butted to the outer peripheral surface of the horizontal cylindrical body, and the outer peripheral edge (corner angle) of the butted surface is welded along the outer peripheral edge.

JP-A-8-120665 JP 2001-3352 A

  On the other hand, in the ground improvement device (drilling stirring device) involving mixing and stirring of three-dimensional excavated soil as described above, the horizontal cylindrical body is provided in the construction (mixing and stirring) process in any of them. Intermittent impact is given to the projection piece, and by repeating this, this projection piece is intermittently rotated around the horizontal axis of the horizontal shaft together with the horizontal cylindrical body, and its longitudinal rotation is obtained It has a structure. For this reason, since a large moment acts with the large external force at the time of the impact on the fixed portion (welded portion) to the outer peripheral surface of the horizontal cylindrical body of the projecting piece, the welding is broken or There was a case where the projecting piece fell off due to the breakage. In addition, in the fixed structure in which the projecting piece is directly welded to the outer peripheral surface of the horizontal cylindrical body as described above, the projecting piece is relatively elongated like a round bar, so that it receives a striking for its rotation. This is likely to cause bending deformation, and thus the life of the projecting piece tends to be shortened.

  As described above, work involving welding for repair and replacement is required for the prevention of welding breakage in the projecting pieces and the occurrence of large bending deformation in order to prevent the breakage. However, especially when such work becomes work at a ground improvement construction site, there are great difficulties in its repair and replacement work, which also causes construction delays. The reason is that there are circumstances such as the fact that the permanent installation of the welding machine to the construction site is not easy.

  The present invention has been made in view of the above-described problem resulting from the attachment structure by welding of the projecting pieces to the horizontal cylindrical body in the ground improvement device as described above having a structure for mixing and stirring the three-dimensional excavated soil. It is an object of the present invention to provide a mounting structure for the projecting piece to the horizontal cylindrical body which can prevent the breakage of the welding and the occurrence of bending deformation of the projecting piece and simplify and speed up the replacement work. To aim.

The present invention according to claim 1 is characterized in that a rotating digging shaft, a digging blade provided in the vicinity of the tip end thereof, and a position above the digging blade and protruding laterally to the digging shaft. A lateral shaft provided in the form of a horizontal cylinder, a horizontal cylindrical body which is fitted around the horizontal shaft so as to allow relative rotation about its horizontal axis, and the outer peripheral surface of the horizontal cylindrical body The three or more protruding pieces fixed at an angle interval around the horizontal axis of the horizontal shaft and fixed via the shaft at the proximal end, and intermittently hit the protruding pieces when the drilling shaft rotates And a striker for rotating the horizontal cylindrical body around the horizontal axis of the horizontal shaft together with the piece, and the ground improvement device comprising :
The projection piece attachment body has a recess capable of accommodating a shaft portion forming the base end portion of the projection piece on the outer peripheral surface of the horizontal cylindrical body, and the projection piece attachment body whose base end has a larger diameter than the outer diameter of the shaft portion The proximal end face of the projecting piece attachment body is in a butt state and welded at the outer peripheral edge of the proximal end face, and the axial portion forming the proximal end of the projecting piece is accommodated in the recess of the projecting piece attachment body In the ground improvement device in which the projecting piece is detachably attached to the recess with a retaining structure without welding .
The projecting piece attachment body has a tubular or annular shape, the recess is inside the tubular or annular inner peripheral surface, and the tubular or annular outer peripheral surface has a substantially square cross section. The projection attachment body is welded so as to rotate in a diagonal direction of the square in rotation of the horizontal cylindrical body about the horizontal axis of the horizontal shaft .

  According to a second aspect of the present invention, the horizontal cylindrical body has a polygonal cylindrical shape, and the projecting piece attaching body is a plane whose base end surface is a plane and forms an outer peripheral surface of the horizontal cylindrical body. The ground improvement device according to claim 1, wherein the ground improvement device is abutted and welded.

In the invention according to claim 3, an axial through hole is provided at a proximal end portion of the projecting piece in a direction intersecting with the axial direction of the axial portion, and the recess of the projecting piece attaching body is opposed Among the inner wall surfaces, a wall through hole penetrating the wall of the recess is provided at a position corresponding to the shaft through hole when the shaft forming the base end of the projecting piece is accommodated in the recess. Yes,
By the bolting in which the bolt is passed through the wall through hole and the shaft through hole in a state where the shaft portion forming the base end portion of the projecting piece is accommodated in the recess portion in the retaining structure. It is a ground improvement device given in any 1 paragraph of Claim 1 or 2.

In the present invention according to claim 4, an axial through hole is provided at a proximal end portion of the projecting piece in a direction intersecting with the axial direction of the axial portion, and the recess of the projecting piece attaching body is opposed Among the inner wall surfaces, a wall through hole penetrating the wall of the recess is provided at a position corresponding to the shaft through hole when the shaft forming the base end of the projecting piece is accommodated in the recess. Yes,
The retaining structure is obtained by insertion of a split pin passing through the wall through hole and the shaft through hole in a state in which the shaft portion forming the base end portion of the projecting piece is accommodated in the recess. It is a ground improvement device given in any 1 paragraph of 1 or 2.

  According to a fifth aspect of the present invention, an external thread is provided on an outer peripheral surface of a shaft portion which forms a base end of the projecting piece, and an internal thread is provided on an inner peripheral surface of the concave portion. The ground improvement device according to any one of claims 1 and 2, wherein the male screw is screwed to the female screw.

  In the above-mentioned conventional ground improvement device, in the process of use, the projecting pieces are intermittently or intermittently subjected to a large impact, and in addition to deformation and damage such as bending and wear, it is also possible to As described above, since the welding fracture and the falling off of the projecting piece occurred due to the direct welding being fixed, as described above. On the other hand, in the ground improvement device according to the present invention, since the fixing of the projecting piece to the horizontal cylindrical body has the attachment structure of the above configuration, the following unique effects can be obtained.

  In the ground improvement device according to the present invention, the fixing of the protruding piece to the horizontal cylindrical body is a fixing with the protruding piece attaching body interposed by welding the base end face to the outer peripheral surface of the horizontal cylindrical body. The outer diameter of the proximal end portion, which is a welding portion to the outer peripheral surface of the horizontal cylindrical body of the protruding piece attachment body, is larger than the outer diameter of the shaft portion of the protruding piece. Therefore, compared to the fixed structure in which the base end face of the protruding piece is directly butted and welded to the outer peripheral surface of the horizontal cylindrical body as in the conventional ground improvement device, a long welding length (welding range) can be secured. Therefore, the welding strength can be increased. For this reason, it is effective in prevention of the fracture of the welding, and is effective in fallout prevention of the projection piece resulting from the fracture.

  Moreover, in the ground improvement device according to the present invention, the projecting piece is a projecting piece that is accommodated in the projecting piece mounting body welded to the outer peripheral surface of the horizontal cylindrical body, since the shaft portion forming the base end is accommodated. The projection length of itself can be made smaller than that in the prior art in which the projection pieces are directly butt-welded to the outer peripheral surface of the horizontal cylindrical body. For this reason, even if the projecting piece is hit for the rotation (longitudinal rotation), the bending deformation hardly occurs. Therefore, the life of the projecting piece can be extended.

Moreover, in the ground improvement device according to the present invention, even if the projecting piece is deformed and needs to be replaced, the fixing of the projecting piece housed in the projecting piece mounting body is not due to welding, so the exchange at the site simple faster, Ru been achieved the efficiency of work. Moreover, in the ground improvement device according to the present invention, the protrusion attachment body has a tubular or annular shape, and the recess is an inner side of the tubular or annular inner peripheral surface, the tubular or annular The outer peripheral surface of the cross section has a substantially square shape, and the protrusion mounting body is welded so as to rotate in the diagonal direction of the square upon rotation of the horizontal cylindrical body about the horizontal axis of the horizontal shaft. Therefore, the following specific effects can be obtained. That is, since such a welding structure is used, the projecting piece attachment body is rotated in the diagonal direction of the square, so that the earth and sand are cut better than in the case of rotating in the opposite side direction. The resistance in the vertical direction can also be reduced.

As described in the second aspect, by welding by flat butt welding, the strength can be increased together with the simplification of the welded structure. The retaining structure may be bolted as described in claim 3, used a split pin as described in claim 4, or screwed as described in claim 5. It may be attached detachably .

The front view (elevation) which shows the schematic structure of the ground improvement apparatus as a "reference example" different from the ground improvement apparatus of this invention in the point from which a "projection piece attachment body" differs . It is a view (right side view) seen from the arrow A1 direction in the ground improvement device of FIG. 1 and is a striking piece of the horizontal cylindrical body whose rotation about the digging axis is stopped by the rotation of the digging axis. Explanatory drawing of the state which a horizontal cylinder-like body rotates around a horizontal axis with a protruding piece with which it hit. The enlarged view of P1 part of FIG. The partially broken surface view explaining the attachment state of a protrusion piece in S1-S1 line | wire of FIG. The enlarged view of P2 part of FIG. The figure which demonstrates the embodiment of this invention which changed the protrusion piece attachment body into a square cylindrical thing in FIG. In FIG. 4, the partially broken view explaining another attachment state of a protrusion piece.

Before describing the embodiment of the ground improvement device according to the present invention (excavator / stirring device for ground improvement), the “reference example different from the ground improvement device according to the present invention in that“ projected piece attachment body ”is different” The ground improvement device as “1.” will be described in detail with reference to FIGS. In the figure, reference numeral 101 denotes a ground improvement device, and 1 is a substantially cylindrical (or hollow cylindrical) excavating shaft (rotational driving shaft), which is configured to be rotated by rotational driving means (not shown) provided above The drilling blade 2 having a predetermined diameter (drilling diameter D) for digging the ground in the vicinity of the lower end (the tip of the drilling axis) protrudes in a direction substantially perpendicular to the drilling axis 1 by welding It is provided as. In the vicinity of the lower end portion of the drilling shaft 1, a discharge port 1a of the slurry-like solidifying agent is provided, and the solidifying agent (not shown) is discharged from the pumping source through the inside of the drilling shaft 1 into the excavated soil K Are configured to

  A cylindrical body (circular pipe) 5 is externally fitted and mounted on the outer periphery of the excavating shaft 1 as a support of a horizontal shaft 7 described below, and exhibits a double pipe structure. The lower end portion of the cylindrical body 5 is held so as to be positioned above the digging wing 2 by a predetermined height. Is the upper end portion of the cylindrical body 5 fixed to a mount fixing a rotational driving means (motor) (not shown) for rotating the excavating shaft so as not to rotate the cylindrical body 5 around the axis of the excavating shaft 1 , Connected to another rotational drive means (motor) and configured to rotate about the axis G1 of the drilling shaft 1 at a different rotation number in the same direction as the drilling shaft 1 or in a reverse direction at an appropriate rotation number There is.

  On the other hand, on both sides of the lower end portion of the cylindrical body 1, a horizontal shaft 7 having a bar shape having a circular cross section and extending substantially straight at a right angle with the cylindrical body 5 is shown in FIG. It is provided so as to project with a projection length equal to or shorter than the outer diameter of the drilling blade 2 on the left and right. Then, cylindrical horizontal cylindrical bodies 12, 12 are externally fitted (freely fitted) around the horizontal axis (horizontal axis) G2 on the left and right horizontal shafts 7, respectively. However, the horizontal cylindrical body 12 has a large diameter enlarged diameter portion 10 provided at the end of the horizontal shaft 7 so as not to come out of the horizontal shaft 7.

The horizontal cylindrical body 12 may be a circular pipe (a cylindrical one whose outer peripheral surface is also a circle), but in the present reference example (hereinafter, also referred to as "this example" or "the above example") The circumferential surface is circular and the outer circumferential surface is square in cross section (see FIGS. 2, 4 and 5). And although it mentions the details in the part near the excavation axis 1 of the outer side (peripheral surface) of the side cylindrical body 12, it sees from the horizontal axis G2 direction of the horizontal axis 7 (about the horizontal axis) substantially equiangular At intervals (90 ° intervals), the details will be described later, but the round bars forming the projecting pieces 13 are provided in a radial arrangement in a projecting manner (see FIGS. 2, 4 and 5). Along with the horizontal axis G2. In addition, in the upper and lower portions of the drilling shaft 1 between the horizontal shaft 7 and the digging wing 2, the round bar-like striking portion (rotational driving means) 11 is drilled to rotate the projecting piece 13 around the horizontal axis G2. The striking portion 11 is fixed so as to be perpendicular to the shaft 1 and, for example, when the rotation of the horizontal shaft 7 around the drilling shaft 1 is stopped, the striking portion 11 that rotates with the drilling shaft 1 is a horizontal cylindrical body The projecting piece 13 and the striking portion are intermittently (intermittently) in contact with the projecting piece 13 provided on 12 so that the projecting piece 13 can be intermittently rotated (vertically) around the horizontal axis G2 together with the horizontal cylindrical body 12 11 is provided in length and arrangement. In addition, since the excavated soil is mixed and stirred around the horizontal axis G2 by excavating the ground and the projecting pieces 13 vertically rotating, the projecting pieces 13 also play the role of a stirring body. Of the outer peripheral surface of the cylindrical body 12, on the outer side (opposite to the digging axis) from the projecting piece 13, separately from it, the stirring body 15 consisting of a shorter round rod has an equal angle similar to that of the projecting piece 13. At intervals, welding is provided to enhance mixing and agitation around the horizontal axis G2 of the excavated soil. Note that the upper edge portion 2 a of the digging wing 2 may hit the projecting pieces 13 and 13 and rotate the horizontal cylindrical body 12 together with the projecting piece 13 without providing the independent striking part 11.

  Next, the mounting structure of the projecting piece 13 to the outer peripheral surface of the horizontal cylindrical body 12 will be described (see FIGS. 4 and 5). In the present embodiment, the projecting piece attaching body 21 is welded to the outer peripheral surface (plane) of the horizontal cylindrical body 12 as follows. That is, it has a recessed portion 22 which penetrates the shaft portion which forms the base end portion (the end portion on the side of the side cylindrical body 12) of the projecting piece 13 in the plane which is the outer peripheral surface of the side cylindrical body 12 The projecting piece attachment body 21 having a short cylindrical shape in which the proximal end 23 has a larger diameter than the outer diameter of the shaft portion brings the proximal end surface (plane) of the projecting piece attachment body 21 into butt state, As weld bead (see double hatching in the figure) B exists along the peripheral edge (circle) (see FIGS. 3 to 5), that is, the outer peripheral surface (plane) of the horizontal cylindrical body 12 and the projection attachment body The weld bead B is welded along a corner with the outer circumferential surface 21. And the axial part which makes the base end of projection piece 13 is accommodated in crevice (short cylinder) 22 of projection piece attaching body 21, and projection piece 13 is bolted without welding as described below, The recess 22 is detachably attached with a retaining structure. In addition, although the protrusion piece attachment body 21 is made into the cylindrical thing penetrated in this example, it is good also as a cylinder with a bottom.

  The attachment structure of the projecting piece 13 may be removable if it is a retaining structure with respect to the recess 22. In this example, the proximal end of the projecting piece 13 accommodated in the recess (short cylinder) 22 The (shaft) has a retaining structure in which a bolt 31 passes in a direction perpendicular to the axis, and is detachable by tightening a nut 35 at the tip of the bolt 31. That is, in this example, the axial through hole 14 is provided at the base end portion of the projecting piece 13 in the direction intersecting the axial direction of the axial portion thereof, and the opposing inner wall surface of the concave portion 22 of the projecting piece mounting body 21 And a wall through hole 25 penetrating the wall of the recess 22 is provided at a position corresponding to the shaft through hole 14 when the shaft forming the base end of the projecting piece 13 is accommodated in the recess 22. In the accommodated state, the bolt 31 is passed through the wall through hole 25 and the shaft through hole 14, and the tip of the bolt 31 is tightened with a nut 35.

  In this example, when the digging shaft 1 is rotated without rotating the cylindrical body 5 which is the outer tube, as shown in the left and right views of FIG. Intermittently contact with the projecting pieces (round bars) 13 and 13 provided on the horizontal cylindrical body 12 externally fitted to the horizontal shaft 7, and the projecting piece 13 is a horizontal cylindrical body 12 around the horizontal axis G2. Rotate with (longitudinal rotation). In the present embodiment, due to the structure, the projecting pieces 13 of the left and right horizontal shafts 7 rotate in opposite directions when viewed from the direction of the axis G2.

  In this ground improvement device 101 of this example, when the drilling axis 1 rotates and enters the ground (in the ground) based on its structure, drilling starts with the drilling blade 2 and soil K is drilled with the drilling blade 2 The ground is mixed and stirred around the axis 1, and the ground is excavated in a cylindrical shape with an excavating diameter D substantially the same as the diameter of the digging blade 2. At this time, the cylindrical body 5 is controlled to stop or reverse, or to rotate at a different rotation speed in the same direction as the drilling axis 1, but in the drilling process, as described above, the drilling axis The striking portion 11 provided in 1 intermittently contacts the protruding pieces 13 provided on the horizontal cylindrical body 12, and rotates the protruding piece 13 and the stirring piece 15 around the axis G2 of the horizontal shaft 7, and in that state The excavated soil (soil) K is mixed and agitated three-dimensionally because the excavating proceeds under

  On the other hand, in the mixing and stirring process, the projecting piece 13 which is hit by the striking portion 11 is in the recess 22 through the projecting piece attaching body 21 welded with the base end face butted to the outer peripheral surface of the horizontal cylindrical body 12. And the attachment structure by inserting the proximal end. The outer diameter of the base end 23 of the projecting piece attachment body 21, which is a welding portion to the outer peripheral surface of the horizontal cylindrical body 12, is larger than the outer diameter of the shaft portion of the projecting piece 13. That is, as compared with the fixed structure in which the base end face of the projecting piece is directly butted and welded to the outer peripheral surface of the horizontal cylindrical body as in the conventional ground improvement device, the weld length (the circumference around the shaft of the bead Since the long length can be secured, the welding strength can be improved. For this reason, it is effective in prevention of a fracture of a welding part to horizontal cylinder 12 of projecting piece attachment object 21, and effective in fall prevention of projecting piece 13 resulting from the fracture. In particular, in the present embodiment, the welding of the protruding piece attaching body 21 to the outer peripheral surface of the horizontal cylindrical body 12 is a welding by butting each other between planes, so the welding structure can be simplified. However, although not shown, the shape of the horizontal cylindrical body 12 may be such that the cross section (periphery) is not a square as in this example, but a circular tube (cylindrical). It can be appropriate. The projecting piece attachment body is preferably welded in a structure in which the entire outer peripheral edge of the end face is in a butt-like shape on the outer peripheral surface of the horizontal cylindrical body 12.

  Moreover, in this example, the protrusion piece 13 itself is the protrusion piece 13 itself, since the shaft part which makes a base end part is accommodated in the protrusion piece attachment body 21 welded to the outer peripheral surface of the horizontal cylindrical body 12. Can be made smaller than in the prior art in which the projecting pieces are directly butt-welded to the outer peripheral surface of the horizontal cylindrical body. For this reason, even if the protrusion piece 13 receives the impact | damage for the rotation (longitudinal rotation), it is hard to produce bending deformation, therefore the extension of the lifetime of the protrusion piece 13 is achieved. Moreover, even if the projecting piece 13 needs to be deformed and replaced, the fixing of the projecting piece housed in the projecting piece attachment body 21 is simple because of the bolting structure that does not rely on welding, so that the on-site replacement can be simplified. Speeding up and work efficiency can be achieved.

Incidentally, the projecting piece mounting body 21 is different from that cylindrical, as in the aforementioned Reference Example, since the cross-section (periphery) is square, as projected piece mounting body 21 shown in FIG. 6, the protruding It is preferable to weld the protruding piece attaching body 21 to the outer peripheral surface of the horizontal cylindrical body 12 so that the projecting piece attaching body 21 rotates in the diagonal direction of the square in the longitudinal rotation of the piece 13 (rotation of the horizontal cylindrical body 12). . In the case of such a welded structure, since the projecting piece attachment body 21 is rotated in the diagonal direction of the square, the pieces of soil are better cut than in the case of rotating in the opposite direction, and This is because the resistance in the vertical direction can also be reduced. In the ground improvement device of the above-mentioned reference example explained based on FIGS. 1-5, what made the protrusion piece attachment body the protrusion piece attachment body 21 shown in FIG. 6 implements the ground improvement device according to the present invention It is a form example.

  In the above example, the retaining structure of the projecting piece 13 with respect to the recess 22 is the above-described bolted structure, but instead of the bolt, a pin (for example, a split pin) which can ensure its own retaining prevention is used. The two leg ends may be bent so as to be retained. The retaining structure is because the retaining of the protruding piece from the recess can be obtained and it may be removable. As another example, as shown in FIG. 7, a male screw 17 is provided on the inner peripheral surface of the recess 22 while a male screw 17 is provided on the outer peripheral surface of the shaft forming the base end of the projecting piece 13. The male screw 17 may be screwed into the female screw (screw hole) 27 and screwed.

  The present invention is not limited to the application to the ground improvement device of the above example, and the excavating shaft which is rotating, the excavating wing provided in the vicinity of the tip end thereof, and the excavating excavating wing above the excavating wing A horizontal shaft is provided on the shaft so as to project laterally of the digging shaft, and a horizontal cylindrical body fitted on the horizontal shaft so as to allow relative rotation about its horizontal axis. And three or more projecting pieces fixed at the outer peripheral surface of the horizontal cylindrical body about the horizontal axis of the horizontal shaft at an angle interval through the shaft portion of the base end, and the excavating shaft rotates The present invention can be widely applied to a ground improvement device comprising: an impact part which intermittently contacts the projecting piece and rotates the horizontal cylindrical body around the horizontal axis of the horizontal shaft together with the projecting piece.

  That is, in the ground improvement device 101 of the above example, the horizontal shaft 7 rotating relative to the digging shaft 1 is stopped by stopping rotation of the cylindrical tubular body (outer pipe) 5 externally fitted to the digging shaft, Although it is embodied in the one that controls the rotation, for example, the cylindrical body (outer pipe) 5 is not extended upward and is short, and can freely rotate around the digging axis at a predetermined height position, The projection length of the horizontal shaft provided on this is made larger than the outer diameter of the drilling blade, and the tip of the horizontal shaft is made to enter the outside of the ground excavated by the drilling blade during the drilling process, The rotation of the horizontal shaft about the drilling axis may be restricted. Moreover, in rotation of the digging shaft, not only the striking portion but also the horizontal shaft rotates integrally with the digging shaft, while the striking portion is stopped without rotating and the projecting piece that rotates with the lateral shaft is this striking It may be designed to rotate around the horizontal axis of the horizontal shaft by hitting the part. That is, in this case, the horizontal shaft is provided to rotate with the digging shaft, and the striking portion is freely rotatably provided around the digging shaft like the horizontal shaft in the above example, and the striking in rotation of the digging shaft By setting the unit as described above, the rotation about the digging axis may be stopped or the rotation may be controlled.

  That is, according to the present invention, the projecting piece provided on the horizontal cylindrical body rotatably fitted around the horizontal axis to the horizontal shaft so as to stop or control the rotation about the drilling axis is excavated. The striking part rotating with the shaft hits, or the projection piece provided on the horizontal cylindrical body rotatably fitted around the horizontal axis to the horizontal shaft rotating with the drilling axis, rotates around the drilling axis Is a conventional well-known ground improvement device having a configuration in which a projecting piece of a horizontal cylindrical body externally fitted to a horizontal shaft is vertically rotated by being hit or stopped when the striking portion provided is stopped or controlled. It can be widely applied as an attachment structure to a horizontal cylindrical body of a piece.

1 drilling axis 2 drilling wing 2a upper edge of drilling wing 5 cylindrical body (support)
Reference Signs List 7 horizontal axis body 11 hitting portion 12 horizontal cylindrical body 13 stirring body 14 axis through hole 15 stirring piece 17 male screw 21 projecting piece attaching body 22 concave portion 23 proximal end of projecting piece attaching body 25 wall through hole 27 female thread 31 bolt 101 ground improvement Apparatus G1 Axis of drilling axis G2 Horizontal axis of horizontal axis B Bead for welding K Drilling soil (soil)

Claims (5)

A rotating drilling shaft, a drilling blade provided in the vicinity of the tip thereof, and a horizontal shaft which is provided above the drilling blade and which protrudes to the drilling shaft in the lateral direction of the drilling shaft; A horizontal cylindrical body which is externally fitted so as to be rotatable relative to the horizontal shaft about its horizontal axis, and an angular interval around the horizontal axis of the horizontal shaft on the outer peripheral surface of the horizontal cylindrical body And three or more projecting pieces fixed via the shaft portion of the base end, and when the drilling shaft rotates, intermittently hit the projecting pieces and the lateral piece with the projecting pieces. a hitting unit for rotating the horizontal axis line of the shaft, a soil improvement device including a
The projection piece attachment body has a recess capable of accommodating a shaft portion forming the base end portion of the projection piece on the outer peripheral surface of the horizontal cylindrical body, and the projection piece attachment body whose base end has a larger diameter than the outer diameter of the shaft portion The proximal end face of the projecting piece attachment body is in a butt state and welded at the outer peripheral edge of the proximal end face, and the axial portion forming the proximal end of the projecting piece is accommodated in the recess of the projecting piece attachment body In the ground improvement device in which the projecting piece is detachably attached to the recess with a retaining structure without welding .
The projecting piece attachment body has a tubular or annular shape, the recess is inside the tubular or annular inner peripheral surface, and the tubular or annular outer peripheral surface has a substantially square cross section. A ground improvement device characterized in that, in rotation of the horizontal cylindrical body about the horizontal axis of the horizontal shaft, the projecting piece attachment body is welded so as to rotate in the diagonal direction of the square .   The horizontal cylindrical body has a polygonal cylindrical shape, and the projecting piece attachment body is welded with its base end face in a flat plane forming the outer peripheral surface of the horizontal cylindrical body. The ground improvement device according to claim 1 characterized by the above. An axial through hole is provided at a base end portion of the projecting piece in a direction intersecting with the axial direction of the axial portion, and the concave portion of the projecting piece mounting body has the concave portion facing the concave portion. A wall through hole penetrating the wall of the recess is provided at a position corresponding to the axial through hole when the axial portion forming the base end of the projecting piece is accommodated.
By the bolting in which the bolt is passed through the wall through hole and the shaft through hole in a state where the shaft portion forming the base end portion of the projecting piece is accommodated in the recess portion in the retaining structure. The ground improvement device according to any one of claims 1 or 2. An axial through hole is provided at a base end portion of the projecting piece in a direction intersecting with the axial direction of the axial portion, and the concave portion of the projecting piece mounting body has the concave portion facing the concave portion. A wall through hole penetrating the wall of the recess is provided at a position corresponding to the axial through hole when the axial portion forming the base end of the projecting piece is accommodated.
The retaining structure is obtained by insertion of a split pin passing through the wall through hole and the shaft through hole in a state in which the shaft portion forming the base end portion of the projecting piece is accommodated in the recess. Ground improvement device given in any 1 paragraph of 1 or 2.   An external thread is provided on the outer peripheral surface of the shaft portion that forms the base end portion of the projecting piece, and a female screw is provided on the inner peripheral surface of the recess, and the retaining structure is a screwing structure of the male screw to the female screw The ground improvement device according to any one of claims 1 or 2, wherein

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