JP5793365B2 - Excavator and excavation method - Google Patents

Description

  The present invention relates to an excavator and a method for excavating the ground.

  As an excavator for excavating the ground, an excavator for excavating the ground by rotating the cutter disposed around the tip of the main shaft and revolving the cutter around the main shaft is known (for example, (See Patent Documents 1 and 2). The excavators described in Patent Documents 1 and 2 are provided with a mechanism for changing the excavation diameter. In the excavator described in Patent Document 1, the excavating diameter is changed by rotating a vertical cutter shaft together with a gear box supporting the cutter shaft. Further, in the excavator described in Patent Document 2, the excavating diameter is changed by expanding and contracting the cutter shaft that is inclined so as to expand in the outer diameter direction toward the hole wall.

Japanese Examined Patent Publication No. 62-38512 JP 2007-262820 A

  The excavator described in Patent Document 1 has a gear box on the cutter. Therefore, when the excavating diameter is increased during excavation of the hole, the gear box interferes with the hole wall. Therefore, it is not suitable for use in the construction of a foundation pile having a node part or an expanded bottom part. Moreover, although the excavator described in Patent Document 2 can be used to construct a foundation pile having a node portion and an expanded bottom portion, the inclination angle of the cutter shaft with respect to the main shaft is small, and the extension length of the cutter shaft is Since the amount of change in excavation diameter is small, the extension length of the cutter shaft must be increased to use it for foundation piles with large-diameter nodes and expanded bottoms. Turn into.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the excavator which can enlarge the change amount of an excavation diameter, without causing the enlargement of a machine.

In order to solve the above-described problem, an excavator according to the present invention is an excavator that excavates a hole by rotating and revolving a plurality of drum cutters, and a shaft disposed along a revolution axis, a revolving portion rotatably supported by the shaft, the revolution driving unit for rotating the above patent rolling unit, is arranged parallel to the revolving portion, and a plurality of rotating shaft rotatably supported in the revolving portion, wherein An arm installed on each rotation shaft and extending in the outer diameter direction; a drum cutter supported on the tip side of each of the arms and provided with a rotation shaft so as to be inclined with respect to a plane orthogonal to the revolution shaft; and the drum A rotation drive unit that rotates each cutter around the rotation shaft, and a drum cutter that is installed on each rotation shaft and is supported on the distal end side of the arm by rotating the rotation shaft together with the arm. The outer diameter of the revolving shaft An arm drive unit for advancing and retracting, the said pivot shaft each is interlocked with the installed arm each other, comprising a link mechanism to match the relative position with respect to a plurality of drum cutter each shaft, wherein the link mechanism, wherein A link boss rotatably supported by a shaft, and a plurality of link plate groups having one end connected to the link boss and the other end fixed to any of the plurality of rotating shafts. Is formed by connecting a plurality of link plates.

  In the excavator, the arm may support the drum cutter at a predetermined rotational position in a state where the rotation shaft is inclined downward toward the outer diameter direction of the revolution shaft.

  In the excavator, the plurality of drum cutters may be arranged around the revolution axis at a predetermined angle interval, and the revolution driving unit may alternately turn the revolution unit in one direction and the opposite direction. It may be rotated by a predetermined angle.

Further, the excavation method according to the present invention is a method of excavating a hole using the excavator according to the present invention including a plurality of drum cutters that rotate and revolve , and the arm driving unit rotates the arm. Then, the excavation diameter of the hole is adjusted by moving the drum cutter back and forth in the outer diameter direction of the revolution shaft.

  ADVANTAGE OF THE INVENTION According to this invention, the excavator which can enlarge the change amount of a drilling diameter, without causing the enlargement of a machine can be provided.

1 is an elevation view showing a reverse circulation excavation system including an excavator according to an embodiment. It is an elevation sectional view showing an excavator and a pump. It is the schematic of the 3-3 cross section of FIG. It is an elevational sectional view showing the excavator in an expanded state. It is the schematic of 5-5 cross section of FIG. It is a front view showing a drum cutter 3 is a development view of a peripheral surface of the drum cutter 40. FIG. It is 8-8 sectional drawing of FIG. It is a top view which shows the outline of a link mechanism. It is a top view which shows operation | movement of a link mechanism. It is a top view which shows operation | movement of a link mechanism. It is a top view which shows operation | movement of a link mechanism. It is a top view which shows operation | movement of a link mechanism. It is an elevational sectional view showing an excavator and a pump according to a comparative example. It is the schematic of the 12-12 cross section of FIG. It is a top view which shows the excavator which concerns on other embodiment. (A), (B) is a figure which shows the locus | trajectory of the cutter bit in the excavator in which a cutter rotates around a vertical axis. (A) is a figure which shows the effect | action of the cutter bit of the excavator which concerns on a comparative example, (B) is a figure which shows the effect | action of the cutter bit of the excavator which concerns on this embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an elevation view showing a reverse circulation excavation system 100 including an excavator 10 according to an embodiment. As shown in this figure, the excavation system 100 includes an excavator 10 suitable for excavating hard ground, a crane 102 installed on the ground, and a pump disposed between the excavator 10 and the crane 102. 104, a pipe 106, and the like. The excavator 10 and the pump 104 mounted thereon are supported by the crane 102 via a pipe 106, and are advanced downward by sequentially adding the pipe 106. Further, the excavator 10 includes a diameter adjustment mechanism 30 that adjusts the excavation diameter.

  In the excavation system 100 configured as described above, the pile hole 1 is constructed by excavating the ground with the excavator 10 and discharging the excavated earth and sand together with the muddy water through the pipe 106 by the operation of the pump 104. Then, the bottom diameter of the pile hole 1 is increased by increasing the excavation diameter by the diameter adjusting mechanism 30, thereby constructing the bottom expanded part 2.

  FIG. 2 is an elevational sectional view showing the excavator 10 and the pump 104, and FIG. 3 is a schematic view of a section 3-3 in FIG. As shown in these drawings, the excavator 10 includes a main shaft 12 that is a cylinder connected to a pump 104, a holder portion 14 that is fixed to the upper portion of the main shaft 12, and the main shaft 12 that rotates about its axis. The revolving part 20 supported so as to be able to rotate, the diameter adjusting mechanism 30 provided in the revolving part 20, the three drum cutters 40 supported rotatably on the revolving part 20 via the diameter adjusting mechanism 30, and the revolving part The revolving hydraulic motor 50 that rotates 20 and the three rotating hydraulic motors 60 that rotate the drum cutter 40 in the direction of arrow A shown in FIG. 3 are provided.

  The holder portion 14 is a circular frame in a plan view through which the main shaft 12 is inserted in the center. A revolving hydraulic motor 50 is attached to the inside of the holder portion 14, and an excavator is provided on the outer periphery of the holder portion 14. A guide 16 for maintaining 10 vertical postures is provided. The revolution hydraulic motor 50 is attached to the holder portion 14 so that the rotation axis thereof is parallel to the main shaft 12, and a gear 52 is attached to the output shaft of the revolution hydraulic motor 50.

  The revolution portion 20 includes a cylindrical outer shaft 21 through which the main shaft 12 is inserted, a tip cutter 22 provided at the lower end of the outer shaft 21, and a pair of upper and lower flanges 23 projecting from the outer shaft 21 in the outer diameter direction. 24, a gear 25 attached to the upper portion of the outer shaft 21, and a swivel joint 26 disposed at an intermediate portion in the axial direction of the outer shaft 21. The outer shaft 21 is supported by the main shaft 12 via a bearing 13 so as to be rotatable around the axis. The front end cutter 22 is a conical cutter pointed downward, and a cutter bit is provided downward. Further, the tip cutter 22 has a step between the inner cutter 22A and the outer cutter 22B, and the cutter 22A protrudes downward from the center of the cutter 22B. ing.

  The flanges 23 and 24 are composed of three plate pieces 23A and 24A that are arranged at intervals of 120 ° and extend in the outer diameter direction from the outer shaft 21, and are arranged so that the plate pieces 23A and 24A face each other vertically. ing. Further, the plate piece 23 </ b> A is disposed at the center in the vertical direction of the outer shaft 21, and the plate piece 24 </ b> A is disposed at the lower portion of the outer shaft 21. The gear 25 meshes with the gear 52 of the revolution hydraulic motor 50, and the output of the revolution hydraulic motor 50 is transmitted to the outer shaft 21 via the gears 52, 25, so that the revolution unit 20 rotates counterclockwise. Revolve in the direction of arrow B shown in FIG.

  The swivel joint 26 is a movable joint of hydraulic piping, and is connected to a rotating hydraulic motor 60 and a diameter adjusting hydraulic motor 33 described later, and a hydraulic piping connected to a ground hydraulic pump (not shown). Are coupled around the main shaft 12 so as to be relatively rotatable.

  The diameter adjusting mechanism 30 includes three diameter adjusting units 31 provided corresponding to each drum cutter 40 and a link mechanism 32 for interlocking the three diameter adjusting units 31. The link mechanism 32 is a mechanism for interlocking the three diameter adjustment units 31, and details will be described later.

  The diameter adjusting unit 31 includes a diameter adjusting hydraulic motor 33 installed on the tip of the plate piece 23A, a shaft 34 rotatably supported at both ends by the tip of the plate pieces 23A and 24A, and a shaft 34. And an arm 35 fixed to the lower portion of the head. The shaft 34 is disposed in parallel with the main shaft 12.

  The diameter adjusting hydraulic motor 33 has a vertical output shaft, and a shaft 34 is connected to the output shaft. The arm 35 is a trapezoidal columnar frame extending from the shaft 34 in the outer diameter direction, and a drum cutter 40 and a rotating hydraulic motor 60 are attached to the tip of the arm 35.

  In other words, the drum cutter 40 and the rotating hydraulic motor 60 are supported by the tip portions of the plate pieces 23A and 24A via the arm 35 and the shaft 34 so as to be rotatable around the axis of the shaft 34, thereby adjusting the diameter. When the shaft 34 is rotated by the hydraulic motor 33, the shaft 34 is rotated around the axis of the shaft 34 (that is, around an axis parallel to the main shaft 12).

  In the excavator 10 according to the present embodiment, the arm cutter 35 is rotated in the revolving direction to move the drum cutter 40 to the enlarged diameter side. Therefore, when the diameter adjusting hydraulic motor 33 is not operated. The drum cutter 40 and the arm 35 try to return to the reduced diameter side by the force received from the hole wall. Further, the shaft 34 and the flange 23 prevent the arm 35 from rotating from the position where the excavation diameter is minimum to the center side (clockwise direction in the figure) and rotate more than the maximum rotation angle. A stopper (not shown) is provided to prevent this.

  As shown in FIG. 3, in a state where the excavation diameter is minimum (hereinafter referred to as a reduced diameter state), the three arms 35 form a regular triangular space on the center side of the pile hole 1 with respect to the shaft 34. The drum cutters 40 are arranged on the outer diameter side of the pile hole 1 with respect to the arms 35. In the reduced diameter state, the drum cutter 40 and the rotating hydraulic motor 60 are arranged such that their rotary shafts 41 and 61 are parallel to the radial direction of the main shaft 12 in plan view.

  Further, as shown in FIG. 2, the drum cutter 40 and the rotating hydraulic motor 60 have their rotation shafts 41 and 61 at a predetermined angle (about 20 ° or the like) obliquely downward toward the outer diameter direction of the pile hole 1. It is arranged to be inclined. That is, the drum cutter 40 is inclined so that the upper side falls down to the outer diameter side of the pile hole 1.

  FIG. 4 is an elevational sectional view showing the excavator 10 in a state where the excavation diameter is the maximum (hereinafter referred to as a diameter expansion state), and FIG. 5 is a schematic view of a section 5-5 in FIG. As shown in FIG. 5, in the expanded diameter state of the excavator 10, the arm 35 is positioned on the outer diameter side of the pile hole 1 with respect to the shaft 34, and the drum cutter 40 and the rotation hydraulic pressure supported on the distal end side of the arm 35. The motor 60 is located on the outer diameter side of the pile hole 1 with respect to the shaft 34. The angle between the arm 35 and the plate piece 23A is a predetermined angle (obtuse angle such as about 150 °).

  6 is a front view showing the drum cutter 40, FIG. 7 is a development view of the peripheral surface of the drum cutter 40, and FIG. 8 is a sectional view taken along the line 8-8 in FIG. Note that the designated positions 1 to 10 in FIG. 6 coincide with the designated positions 1 to 10 in FIG. 7. As shown in these drawings, a plurality of rows (for example, four rows as shown) of cutter bits 42 are arranged on the peripheral surface of the drum cutter 40. The cutter bits 42 in each column are arranged apart from each other in the circumferential direction. The plurality of rows of cutter bits 42 are arranged in a staggered pattern in the circumferential direction. Each cutter bit 42 is fixed to a holder 43 that protrudes from the peripheral surface of the drum in the outer diameter direction. The holder 43 is arranged perpendicular to the rotation shaft 41. The cutting edge of the cutter bit 42 is formed in an obtuse isosceles triangle shape.

  Further, cutter bits 44 and 45 are arranged between the cutter bits 42 in the outermost row (row farthest from the arm 35). Here, the cutter bits 42, 44, 45 are arranged so that the cutting edges thereof face in the counterclockwise direction of FIG. 6, and when the drum cutter 40 rotates in the counterclockwise direction of FIG. 42, 44 and 45 cut the ground.

  The cutter bit 44 is fixed to a holder 46 that protrudes from the peripheral surface of the drum in the outer diameter direction. The holder 46 is disposed so as to be inclined toward the opposite side of the arm 35 in the outer diameter direction of the drum. Further, the cutting edge of the cutter bit 44 is formed in an acute unequal triangular shape, and the acute corner is located on the opposite side of the arm 35 (that is, on the hole wall side) from the outermost cutter bit 42. It is configured as follows.

  Here, the inclination angle of the holder 46 with respect to the plane orthogonal to the rotation axis 41 is the same as the inclination angle of the rotation axis 41 with respect to the axis orthogonal to the main shaft 12. That is, in a state where the drum cutter 40 is attached to the arm 35, the holder 43 is inclined with respect to the vertical line, whereas the holder 46 is parallel to the vertical line.

  The cutter bit 45 is fixed to a holder 47 that protrudes from the peripheral surface of the drum in the outer diameter direction. The cutting edge of the cutter bit 45 is formed in a corrugated shape, and the cutter bit 45 is fixed to the holder 47 so that the corrugated blade faces the tangential direction of the drum peripheral surface.

  FIG. 9 is a plan view showing an outline of the link mechanism 32. As shown in this figure, the link mechanism 32 includes a link boss 36 that is rotatably supported by the main shaft 12, and three sets of link plates 37 and 38 that connect the link boss 36 and each shaft 34. Yes. The link boss 36 includes a disc-shaped center portion 36A and three arm portions 36B extending from the center portion 36A in the outer diameter direction. The three arm portions 36B are arranged at equal intervals (120 ° intervals).

  Each link plate 37 is an elongate plate member that is rotatably supported around the vertical axis (axis parallel to the main shaft 12) at the tip of the arm portion 36B, and each link plate 38 is the tip of each link plate 37 ( It is a plate material shorter than the link plate 37 supported on the opposite end of the support side so as to be rotatable around the vertical axis. Further, the end of each link plate 38 (the end opposite to the support side by the link plate 37) is fixed to the shaft 34.

  9 and 10A to 10D are plan views showing the operation of the link mechanism 32. FIG. As shown in FIG. 9, when the diameter of the excavator 10 is reduced, the link plates 37 and 38 extend in a substantially linear shape. Then, as shown in FIGS. 10A to 10D, when the excavator 10 transitions to the diameter-expanded state, when the arm 35 and the shaft 34 rotate and rotate in the counterclockwise direction around the shaft 34, the shaft When the link plate 38 fixed to 34 rotates counterclockwise in the figure around the shaft 34, the degree of bending of the link plates 37 and 38 increases, and the link boss 36 rotates in the clockwise direction in the figure. Rotate.

  Here, when the link boss 36 rotates in the clockwise direction, the other two sets of link plates 37 and 38 are displaced by the rotational force of the link boss 36 so that the degree of bending increases, and the shaft 34 and the arm 35 are moved. The shaft 34 is rotated and rotated around the shaft 34 in the counterclockwise direction in the figure. As a result, even when the driving speed of the diameter adjusting hydraulic motor 33 varies, the three arms 35 rotate simultaneously at the same speed, and the relative positions of the three drum cutters 40 with respect to the main shaft 12 coincide. .

  Hereinafter, the procedure for constructing the pile hole 1 having the expanded bottom portion 2 using the excavator 10 will be described. First, the excavator 10 in a reduced diameter state is excavated downward to excavate a hole having a uniform diameter (see FIGS. 2 and 3). At this time, the three rotation hydraulic motors 60 are driven to rotate the three drum cutters 40 around the rotation shaft 41 (in the direction of arrow A in the figure), and the revolution hydraulic motor 50 is driven to rotate the revolution section. 20 is rotated around the main shaft 12 (in the direction of arrow B in the figure). That is, the drum cutter 40 is rotated and revolved. The rotation speed is set larger than the revolution speed.

  Here, the rotating shaft 41 of the drum cutter 40 is inclined downward toward the outer diameter direction of the pile hole 1, and the drum cutter 40 is inclined toward the center side of the pile hole 1 toward the lower side. . Therefore, on the upper side of the drum cutter 40, the outer rows of cutter bits 42, 44, 45 abut the hole wall 3 to excavate the hole wall 3, and on the lower side of the drum cutter 40, the entire row of cutter bits 42. , 44 and 45 abut against the hole bottom 4 to excavate the hole bottom 4. At this time, the lower side of the drum cutter 40 is located on the center side of the hole wall 3, and the center side of the hole wall 3 is excavated. Further, the front end cutter 22 of the main shaft 12 excavates the central portion of the hole bottom 4, that is, the inner peripheral side of the range where the lower side of the drum cutter 40 is excavated.

  That is, the excavator 10 in the reduced diameter state excavates while cutting the natural ground into a hemispherical shape with a diameter decreasing downward with the drum cutter 40 and the tip cutter 22. At this time, the digging force of the hole wall 3 is improved because the outermost cutter bits 44 are configured to incline into the hole wall 3 while being inclined toward the hole wall 3 side. Further, the drum cutter 40 is inclined so that the lower side thereof is closer to the center side of the pile hole 1, thereby narrowing a range where the drum cutter 40 cannot be excavated around the center of the hole bottom 4 excavated by the tip cutter 22. Can do.

  Further, since the drum cutter 40 is inclined to the outer diameter side of the pile hole 1 toward the upper side, the shape of the upper peripheral surface of the drum cutter 40 in plan view swells to the outer diameter side of the pile hole 1. It becomes an arc shape. That is, the cutter bits 42, 44, 45 in the outer row of the drum cutter 40 are arranged along an arcuate curve that swells to the outer diameter side of the pile hole 1 in a plan view. Thus, the hole wall 3 can be excavated in an arc shape, and thus the pile hole 1 can be excavated smoothly.

  On the other hand, as shown in FIGS. 11 and 12, when the rotating shaft 41 of the drum cutter 40 is set to be horizontal, the shape of the drum cutter 40 in plan view is rectangular. That is, the cutter bits 42, 44, 45 in the outer row of the drum cutter 40 are linearly arranged in a plan view, so that the hole wall 3 is formed at two points on the drum cutter 40 only by the rotation of the drum cutter 40. Excavation is performed only at the corners, and the pile hole 1 is excavated roughly as compared with the present embodiment.

  When a hole having a uniform diameter is excavated as described above, the excavator 10 is pulled up to the upper side of the position where the bottom expansion portion 2 is formed, and then the drum cutter 40 is gradually rotated to the diameter expansion side by the diameter adjustment mechanism 30. By moving the excavator 10 downward while moving, the truncated cone-shaped expanded bottom portion 2 that gradually expands in the downward direction is excavated (see FIGS. 4 and 5). At this time, there is no mechanism for driving the drum cutter 40 above the drum cutter 40, and the arm 35 is located closer to the center of the pile hole 1 than the drum cutter 40. That is, when the drum cutter 40 is moved to the outer diameter side of the pile hole 1, there is no obstacle that interferes with the hole wall 3, so that the excavation diameter can be increased during excavation of the pile hole 1. It is possible and it is possible to excavate the pile hole 1 which has the expanded bottom part 2. FIG.

  Further, the arm 35 that supports the drum cutter 40 that rotates about the horizontal axis on the tip side rotates around the shaft 34 that is arranged around the main shaft 12 in parallel with the main shaft 12. And the difference in the excavation diameter in the expanded state can be increased so as to exceed the diameter of the drum cutter 40. Therefore, since the amount of change in the excavation diameter can be increased without increasing the members such as the arm 35 and the flanges 23 and 24, the amount of change in the excavation diameter can be increased without increasing the size of the excavator 10. An expanded pile having the expanded bottom portion 2 having a large bulge can be constructed.

  By the way, in the excavator in which the cutter rotates around the vertical axis as described in the above-mentioned Patent Documents 1 and 2, the entire surface on which the cutter bit of the cutter is provided contacts the bottom of the hole, and all the cutter bits Always contacts the bottom of the hole. On the other hand, in the excavator 10 according to the present embodiment, the hole wall 3 and the hole bottom 4 are excavated by the drum cutter 40 provided with the cutter bits 42, 44, 45 on the peripheral surface. 4 is not the entire circumference of the drum cutter 40 but one point. Therefore, in the excavator 10 according to the present embodiment, the force acting on each cutter bit is larger than that of the excavator in which the cutter rotates around the vertical axis, and the excavating force (crushing) of each cutter bit is increased. Force) increases. Accordingly, slippage is unlikely to occur between the cutter bit and the ground, and wear of the cutter bits 42, 44, 45 is suppressed, so that it is possible to cope with excavation of hard ground.

  In the excavator 10 according to the present embodiment, the three arms 35 are interlocked, that is, rotated at the same speed and the same phase by the link mechanism 32. Therefore, even when the driving force of the diameter adjusting hydraulic motor 33 varies, the three drum cutters 40 can be moved back and forth in the outer diameter direction of the pile hole 1 at the same speed and in the same phase, and the diameter is increased. Even in this case, the roundness of the hole can be ensured.

  FIG. 13 is a plan view showing an excavator according to another embodiment. Note that a description of the same configuration as that of the above-described embodiment is omitted. As shown in FIG. 13, in the excavator according to the present embodiment, the revolution hydraulic motor 50 (see FIG. 2) causes the revolution unit 20 to alternate between the positive direction and the installation interval (about 120 °) of the drum cutter 40. Rotate in the opposite direction (arrow C direction in the figure).

  Here, FIGS. 14A and 14B are diagrams showing the locus of the cutter bit in the excavator in which the cutter 9 as described in Patent Documents 1 and 2 rotates around the vertical axis. As shown in FIG. 14A, in the excavator, when the revolution direction and the rotation direction of the cutter 9 are the same, the locus of the cutter bit is a curve that approximates an epitrochoid (outer trochoid) curve. 5 will be drawn. In this case, it is always possible to cut the ground with the rake angle of the cutter bit. On the other hand, as shown in FIG. 14B, when the revolution direction and the rotation direction of the cutter 9 are reversed, the locus of the cutter bit draws a curve 6 that approximates the inner trochoid curve. . In this case, the ground bit can be cut at the rake angle of the cutter bit while the cutter bit moves toward the hole wall, but the cutter bit escapes while the cutter bit moves toward the center of the hole. It will be impossible to excavate because it is going to cut a natural ground at the corner.

  For this reason, when an excavator with a cutter rotating around the vertical axis tries to excavate a hole while rotating the cutter in the forward and reverse directions, as shown in FIG. During this process, the ground bit will be cut at the clearance angle of the cutter bit 7 and excavation may become impossible. This is because, in the excavator, the cutter bit 7 is always in contact with the natural ground.

  On the other hand, as shown in FIG. 15 (B), in the excavator according to the present embodiment, since the drum cutter 40 rotates around the horizontal axis, the cutter bits 42 and 44 are used regardless of the revolution direction. The ground will be cut at the rake angle, and excavation is possible. Therefore, in the excavator according to the present embodiment, it is possible to excavate the pile hole 1 while rotating the revolving part 20 in the forward and reverse directions by the installation interval of the drum cutter 40.

  Here, in the excavator 10 according to the above-described embodiment, the diameter adjusting hydraulic motor 33 and the rotating hydraulic motor 60 are installed together with the revolving part 20 in order to keep the revolving part 20 rotating in one direction. It is necessary to be able to rotate continuously in one direction. For this purpose, the diameter adjusting hydraulic motor 33, the rotating hydraulic motor 60 and the hydraulic pump are connected via the swivel joint 26. In contrast, in the excavator according to the present embodiment, the revolving unit 20 is configured to rotate forward and backward alternately by the interval of the drum cutter 40, so that the swivel joint 26 can be eliminated.

  In addition, the above-mentioned embodiment is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof. For example, in the above-described embodiment, the present invention has been described by taking the reverse circulation excavator 10 as an example, but the present invention can also be applied to other excavators such as a boring machine. Further, the excavation direction by the excavator is not limited to the downward direction, and may be an obliquely downward direction or a horizontal direction. Furthermore, although the revolution drive unit, the rotation drive unit, and the diameter adjustment drive unit are hydraulic motors, they are not essential and may be electric motors.

DESCRIPTION OF SYMBOLS 1 Pile hole, 2 Expanded bottom part, 3 Hole wall, 4 Hole bottom, 5 and 6 Curve, 7 Cutter bit, 9 Cutter, 10 Excavator, 12 Main shaft (shaft), 13 Bearing, 14 Holder part, 16 Guide, 20 Revolving part, 21 Outer shaft, 22 Tip cutter, 22A, 22B Cutter part, 23, 24 Flange, 23A, 24A Plate piece, 25 Gear, 26 Swivel joint, 30 Diameter adjusting mechanism, 31 Diameter adjusting unit, 32 Link mechanism, 33 Diameter adjusting hydraulic motor (arm drive part), 34 shaft (rotating shaft) , 35 arm, 36 link boss, 36A center part, 36B arm part, 37, 38 link plate, 40 drum cutter, 41 rotating shaft, 42 cutter Bit, 43 Holder, 44, 45 Cutter bit, 46, 47 Holder, 50 Revolution hydraulic motor (revolution drive unit), 52 Gear, 60 Rotation Hydraulic motor (rotation drive), 61 rotary shaft, 100 excavation system, 102 crane, 104 pump, 106 pipe

Claims (4)

An excavator that excavates a hole by rotating and revolving a plurality of drum cutters,
A shaft arranged along the revolution axis;
A revolving part rotatably supported by the shaft;
A revolution drive unit for rotating the revolution unit;
A plurality of pivot shafts arranged in parallel with the revolution part and rotatably supported by the revolution part ;
An arm installed on each of the rotation shafts and extending in the outer diameter direction ;
A drum cutter that is supported on the tip side of each of the arms and includes a rotation axis so as to be inclined with respect to a plane orthogonal to the revolution axis;
A rotation driving section for rotating each of the drum cutters around the rotation axis;
An arm driving unit that is installed on each of the rotation shafts, and that rotates the rotation shaft together with the arm to move the drum cutter supported on the distal end side of the arm in the outer diameter direction of the revolution shaft;
A link mechanism that interlocks the arms installed on each of the rotating shafts to match the relative position of each of the plurality of drum cutters , and
The link mechanism includes a link boss rotatably supported on the shaft, and a plurality of link plate groups having one end connected to the link boss and the other end fixed to any of the plurality of rotating shafts. Each of the link plate groups is formed by connecting a plurality of link plates.   2. The excavator according to claim 1, wherein the arm supports the drum cutter at a predetermined rotation position in a state where the rotation shaft is inclined downward toward an outer diameter direction of the revolution shaft. The plurality of drum cutters are arranged at predetermined angular intervals around the revolution axis,
The excavator according to claim 1 or 2 , wherein the revolution drive unit rotates the revolution unit alternately in the one direction and the opposite direction by the predetermined angle. A method for drilling a hole using the excavator according to any one of claims 1 to 3, comprising a plurality of drum cutters that rotate and revolve .
An excavation method for adjusting the excavation diameter of the hole by rotating the arm by the arm drive unit and moving the drum cutter forward and backward in the outer diameter direction of the revolution shaft.

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