JP2018111984A - Pile extraction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile extraction device having a simple structure, which can extract a pile while holding it without using a hydraulic cylinder.SOLUTION: A pair of holding pieces 15 are mounted on the lower end of an inner cylinder 10 so as to face each other in a diameter direction. An excavation blade 25 is provided on the lower end of an outer cylinder 20. A pair of the holding pieces 15 are rotatable between an opening position where their lower ends 15b are separated from each other, and a closing position where their lower ends approach each other. The outer cylinder 20 stores at least the lower end of the inner cylinder 10 and a pair of the holding pieces 15 within the outer cylinder 20, is disposed coaxially with the inner cylinder 10 and is movable spirally in a predetermined range with respect to the inner cylinder 10. A pair of the holding pieces 15 interlock with the movement of the outer cylinder 20 with respect to the inner cylinder 10 so that a pair of the holding pieces 15 are located at the opening position when the outer cylinder 20 is at the uppermost position with respect to the inner cylinder 10, and so that a pair of the holding pieces 15 are located at the closing position when the outer cylinder 20 is at the lowermost position with respect to the inner cylinder 10.SELECTED DRAWING: Figure 1C

Description

  The present invention relates to a pile removing device used for extracting a pile embedded in the ground.

  In ground structures such as buildings, condominiums, and factories, piles are embedded up to the solid ground in order to support the load. When dismantling these ground structures, it is necessary to pull out and remove the piles embedded in the ground. An example of a pile removing device used for pulling out a pile is described in Patent Document 1.

  The pile removing device of Patent Document 1 includes a cylindrical casing having a lower end provided with a digging blade, and a pair of gripping pieces facing in the diametrical direction. The pair of grip pieces are provided in the casing at a position near the lower end of the casing. A pair of pivots are provided at both ends of the upper end edge of the arc shape of each grip piece, and each pivot passes through the casing. By rotating the gripping piece about the pivot, the pair of gripping pieces can be switched between an open state in which a pile can be inserted between them and a closed state in a conical shape. The pair of gripping pieces are held in an open state, and the casing is dug into the ground so that the pile is accommodated in the casing. After the pile is stored in the casing, the pair of grip pieces are switched to the closed state. A pair of gripping pieces are held so as to crawl the lower end of the pile. If the casing is pulled up in this state, the pile can be pulled up to the ground while being housed in the casing.

JP 2012-097444 A

  The conventional pile removing device of Patent Document 1 uses a hydraulic cylinder as a power source for opening and closing a pair of gripping pieces. For this reason, it has the following subjects.

  In the conventional pile removing apparatus, the hydraulic cylinder is provided near the upper end of the casing. It is necessary to transmit the vertical movement of the piston of the hydraulic cylinder to the grip piece provided near the lower end of the casing to rotate the grip piece. This complicates the structure of the pile removal device.

  Further, in the above conventional pile removing device, a hydraulic system including a hydraulic source (hydraulic pump) for driving the hydraulic cylinder and a hydraulic pipe connecting the hydraulic source and the hydraulic cylinder is separated from the pile removing device. is necessary. This complicates the entire device required for the pile removal operation. It is necessary to construct and disassemble the hydraulic system accompanying the pile removal work. This complicates and lengthens the work associated with pile removal.

  Furthermore, in order to open and close the pair of grip pieces, it is necessary to appropriately operate the hydraulic cylinder. That is, in addition to the operations for excavating and retreating the ground of the pile removing device, it is necessary to operate the hydraulic cylinder. This complicates the work procedure for pile removal.

  An object of this invention is to solve the subject which said conventional pile-drawing apparatus has. That is, an object of the present invention is to realize a pile removing device that can hold and draw a pile with a simple structure without using a hydraulic cylinder.

  The pile removing device of the present invention includes a hollow cylindrical inner cylinder, a pair of holding pieces attached to the lower end of the inner cylinder so as to face each other in the diameter direction of the inner cylinder, and a hollow cylindrical shape. And an excavating blade provided at a lower end of the outer cylinder. The pair of holding pieces includes an open position where lower ends of the pair of holding pieces are spaced apart from each other so as to open an opening facing downward of the inner cylinder, and an opening position of the pair of holding pieces facing downward of the inner cylinder. The lower ends of the pair of holding pieces can be rotated between the close positions where they are close to each other. The outer cylinder accommodates at least the lower end of the inner cylinder and the pair of holding pieces in the outer cylinder and is arranged coaxially with the inner cylinder. The outer cylinder can move spirally within a predetermined range with respect to the inner cylinder. When the outer cylinder is in the uppermost position with respect to the inner cylinder, the pair of holding pieces are in the open position, and when the outer cylinder is in the lowest position with respect to the inner cylinder, the pair of holding pieces The pair of holding pieces are interlocked with the movement of the outer cylinder with respect to the inner cylinder so that the pieces are located at the closed position.

  In the pile removing device of the present invention, the pair of holding pieces is opened and closed in conjunction with the relative spiral movement of the outer cylinder with respect to the inner cylinder. If the pile removing device is dug against the ground while rotating the inner cylinder in the forward direction, the pile can be stored in the inner cylinder through a pair of holding pieces maintained in the open position. Then, if the pile removing device is retracted from the ground while rotating the inner cylinder in the reverse direction, the pile can be lifted from the ground while the pair of holding pieces maintained in the closed position hold the pile. Thus, according to the present invention, it is possible to provide a pile removing device that can hold and draw a pile with a simple structure without using a hydraulic cylinder. Since the opening and closing of the pair of holding pieces can be switched simply by reversing the rotation direction of the inner cylinder during excavation and retreating, the work procedure for pile removal is extremely simple.

FIG. 1A is a perspective view as seen from above of a pile removing apparatus according to an embodiment of the present invention in which an outer cylinder is at the uppermost position. FIG. 1B is a perspective view of the pile removing device according to one embodiment of the present invention, as viewed from below, with the outer cylinder in the uppermost position. FIG. 1C is a cross-sectional view along the central axis of the pile removing device according to one embodiment of the present invention, in which the outer cylinder is at the uppermost position. FIG. 2 is an exploded perspective view of a pile removing device according to an embodiment of the present invention in which a pair of holding pieces are in an open position. Drawing 3 is a perspective view seen from the lower part of the inner cylinder which constitutes the pile removing device concerning one embodiment of the present invention which has a pair of holding pieces in an open position. FIG. 4A is a perspective view of the pile removing device according to the embodiment of the present invention, as seen from above, with the outer cylinder at the lowest position. FIG. 4B is a perspective view of the pile removing device according to the embodiment of the present invention, as viewed from below, with the outer cylinder at the lowest position. FIG. 4C is a cross-sectional view along the central axis of the pile removing device according to the embodiment of the present invention, in which the outer cylinder is at the lowest position. FIG. 5: A is a figure which shows the pile extraction operation | work using the pile extraction apparatus concerning one Embodiment of this invention, Comprising: The state just before excavating the ground is shown, rotating an inner cylinder forward. FIG. 5B is a diagram showing a pile removing operation using the pile removing apparatus according to one embodiment of the present invention, and shows a state in which the pile is inserted into the pile removing apparatus. FIG. 5C is a diagram showing a pile removing operation using the pile removing apparatus according to one embodiment of the present invention, and shows a state in which the inner cylinder is reversely rotated to switch the pair of holding pieces to the closed position. FIG. 5D is a diagram showing a pile removing operation using the pile removing device according to one embodiment of the present invention, and shows a state where a wire is wound around a pile protruding from the pile removing device. FIG. 5E is a diagram showing a pile removing operation using the pile removing apparatus according to one embodiment of the present invention, and shows a state in which the pile is pulled up from the pile removing apparatus.

  In the above pile removing device of the present invention, one of the inner cylinder and the outer cylinder may be provided with a spiral cam groove, and the other of the inner cylinder and the outer cylinder is the cam You may provide the cam pin inserted in a groove | channel. In this case, the cam groove and the cam pin constitute a spiral cam. Thereby, it is possible to move the outer cylinder in a spiral relative to the inner cylinder with a simple configuration.

  The outer cylinder may include a guide groove along the circumferential direction. The holding piece may include a guide piece that fits into the guide groove. When the outer cylinder moves spirally with respect to the inner cylinder, the guide piece may move in the circumferential direction in the guide groove. Thereby, with a simple configuration, the holding piece can be rotated between the open position and the closed position in conjunction with the relative spiral movement of the outer cylinder with respect to the inner cylinder.

  In the above, the guide piece may be provided at substantially the center of the substantially arc-shaped upper end edge of the holding piece. The rotation axis of the holding piece may pass near both ends of the upper end edge. According to such a configuration, since the distance from the guide piece, which is the point of action of the force for rotating the holding piece, to the rotation axis of the holding piece becomes long, the holding piece can be obtained simply by applying a relatively small force to the guide piece. Can be rotated. Therefore, the reliability of the opening / closing operation of the pair of holding pieces is high.

  Below, this invention is demonstrated in detail, showing suitable embodiment. However, it goes without saying that the present invention is not limited to the following embodiments. Each drawing referred to in the following description is a simplified illustration of an embodiment of the present invention. Therefore, within the scope of the present invention, the members or configurations shown in the following drawings may be changed or omitted, and arbitrary members or configurations may be added.

  Drawing 1A is a perspective view seen from the upper part of pile removal device 1 concerning one embodiment of the present invention. FIG. 1B is a perspective view of the pile removing device 1 as viewed from below. FIG. 1C is a cross-sectional view taken along a central axis (not shown) of the pile removing device 1. FIG. 2 is an exploded perspective view of the pile removing apparatus 1. The pile removing device 1 includes an inner cylinder 10 having a hollow cylindrical shape and an outer cylinder 20 having a hollow cylindrical shape. The inner diameter of the outer cylinder 20 is slightly larger than the outer diameter of the inner cylinder 10. The inner cylinder 10 and the outer cylinder 20 are arranged coaxially. The pile removing device 1 has a central axis (the central axis of the pile removing device 1 coincides with the central axis of the inner cylinder 10 and the central axis of the outer cylinder 20 (none of which is shown)) parallel to the vertical direction. (See FIGS. 5A to 5E described later). For convenience of the following description, a direction parallel to the central axis of the pile removing device 1 is referred to as “vertical direction”. “Upper” and “Lower” are defined based on the state when the pile removing device 1 is in use. A direction parallel to a plane perpendicular to the central axis of the pile removing device 1 is referred to as “horizontal direction”, and a direction along a straight line perpendicular to the central axis of the pile removing device 1 is referred to as “diameter direction” or “radial direction”. In the radial direction, the central axis side is referred to as “inside” and the opposite side is referred to as “outside”. The direction rotating around the central axis is called “circumferential direction”.

  FIG. 3 is a perspective view of the inner cylinder 10 as viewed from below. A pair of protrusions 13 (only one protrusion 13 is shown in FIG. 3) is radially outward from a position slightly away from the lower end of the inner cylinder 10 on the outer peripheral surface of the inner cylinder 10. It protrudes. In the present embodiment, the protrusion 13 has a cylindrical shape, but the shape of the protrusion 13 is not limited to this and is arbitrary.

  A pair of holding pieces 15 are provided at the lower end of the inner cylinder 10 so as to face each other in the diameter direction. The holding piece 15 has such a shape that a substantially isosceles trapezoidal (or substantially isosceles triangular) plate is curved in an arc shape (or so as to constitute a semi-cylindrical surface). The radius of curvature of the holding piece 15 is approximately the same as or slightly smaller than that of the inner cylinder 10. The central angle of the holding piece 15 is slightly smaller than 180 degrees. The holding piece 15 is attached to the inner cylinder 10 with the longer base of the substantially isosceles trapezoid (or the base of the substantially isosceles triangle) 15a facing upward. Both ends of the longer base 15 a of each holding piece 15 are attached to a pair of extension pieces 11 protruding downward from the lower end of the inner cylinder 10 using a pair of pins 12. The holding piece 15 can be rotated around the pin 12. The short base of the substantially isosceles trapezoid (or the apex of the approximately isosceles triangle) constitutes the lower end 15 b of the holding piece 15. 1A to 3 show a state in which the pair of holding pieces 15 are rotated so that the lower ends 15b are separated from each other in the diametrical direction. This rotational position of the holding piece 15 is referred to as an “open position”. As shown in FIG. 2, when the holding piece 15 is in the open position, the holding piece 15 is disposed substantially along the inner peripheral surface of the outer cylinder 20 and faces downward of the inner cylinder 10 having a cylindrical shape. The opening is opened downward through the pair of holding pieces 15.

  The guide piece 16 protrudes from the arcuate upper end edge 15a of the holding piece 15 substantially along the radial outward direction. The guide piece 16 is provided at a position substantially at the center of the upper end edge 15a, that is, a position farthest from the straight line passing through the pair of pins 12 that are the rotation shafts of the holding piece 15 in the upper end edge 15a. The guide piece 16 is composed of one end of a plate material bent into a substantially L shape. The other end (inner end) of the plate material is fixed to the inner peripheral surface (surface facing the central axis) of the holding piece 15 by welding or the like (see FIGS. 1C and 3). In the present embodiment, the guide piece 16 is configured as a separate part from the holding piece 15, but the present invention is not limited thereto, and may be configured as one piece integrally with the holding piece 15, for example. Further, the shape of the holding piece 15 does not have to be a plate shape, and is arbitrary, for example, a rod shape.

  As shown in FIG. 1C, a top plate 17 is provided at the upper end of the inner cylinder 10. The top plate 17 closes the opening facing upward of the inner cylinder 10. Although not shown, the top plate 17 is detachably fixed to the inner cylinder 10 using bolts, an arbitrary jig, or the like. The connecting shaft 18 protrudes upward from the top surface of the top plate 17. The connecting shaft 18 is coaxial with the pile removing device 1. The shape of the connecting shaft 18 is a hexagonal column in this embodiment (see FIG. 2), but the present invention is not limited to this and is arbitrary.

  As shown in FIG. 2, the outer cylinder 20 is provided with a pair of grooves 23 and a pair of grooves 26 (only one groove 26 is shown in FIG. 2). The pair of grooves 23 extend over a predetermined length along a spiral (that is, a curve that moves in the direction of the central axis while rotating around the central axis of the outer cylinder 20, also referred to as a chord winding). In the present embodiment, the spiral along the groove 23 is a right-hand thread. On the other hand, the pair of grooves 26 extend over a predetermined length in the circumferential direction along a common horizontal plane. The groove 26 is located below the groove 23. The groove 23 and the groove 26 are slot-like through holes that penetrate the outer cylinder 20 in the radial direction. However, the present invention is not limited to this, and one or both of the groove 23 and the groove 26 may be a non-penetrating groove (concave portion) provided on the inner peripheral surface of the outer cylinder 20.

  An enlarged diameter portion 21 is provided at a position below the groove 26 of the outer cylinder 20. The outer peripheral surface of the enlarged diameter portion 21 is a cylindrical surface having a larger outer diameter than the portion of the outer cylinder 20 above this.

  As shown in FIG. 1B, a plurality of excavation blades 25 protrude downward from the lower end of the outer cylinder 20. The excavation blades 25 are arranged at equiangular intervals with respect to the central axis. The excavation blade 25 has a blade body made of a cemented carbide chip, diamond, or the like at the tip (lower end). The excavating blade 25 excavates the ground when the pile removing device 1 is lowered while excavating into the ground.

  As shown in FIGS. 1A to 1C, the inner cylinder 10 is inserted into the outer cylinder 20. The lower end portion of the inner cylinder 10 and the pair of holding pieces 15 are accommodated in the outer cylinder 20. The protrusion 13 protruding from the inner cylinder 10 is fitted into a spiral groove 23 provided in the outer cylinder 20. The guide piece 16 protruding from the holding piece 15 is fitted into a groove 26 provided in the outer cylinder 20 along the circumferential direction. The portion near the upper end of the inner cylinder 10 and the top plate 17 protrude upward from the outer cylinder 20.

  A spiral groove 23 provided in the outer cylinder 20 functions as a cam groove, and a protrusion 13 provided in the inner cylinder 10 functions as a cam pin (or cam follower), which constitute a so-called spiral cam. Therefore, the outer cylinder 20 can move in a spiral with respect to the inner cylinder 10. That is, when the inner cylinder 10 is rotated with respect to the outer cylinder 20, the outer cylinder 20 is displaced relative to the inner cylinder 10 in the central axis direction (vertical direction). At this time, the guide piece 16 provided in the holding piece 15 moves in the circumferential direction in the groove 26 provided in the outer cylinder 20. Since the outer cylinder 20 moves in the direction of the central axis with respect to the inner cylinder 10, each holding piece 15 is rotated with the pins 12 at both ends thereof as rotation axes. The spiral movement range of the outer cylinder 20 with respect to the inner cylinder 10 is defined by the length of the spiral groove 23.

  1A to 1C show a state where the inner cylinder 10 is inserted into the outer cylinder 20 most deeply (in other words, the outer cylinder 20 is in the “uppermost position” with respect to the inner cylinder 10). The protrusion 13 is located at the lower end of the spiral groove 23. As shown in FIG. 1C, when the outer cylinder 20 is in the uppermost position, the holding piece 15 is in the open position.

  4A to 4C show a pile removing device in which the inner cylinder 10 is inserted most shallowly into the outer cylinder 20 (in other words, the outer cylinder 20 is in the “lowermost position” with respect to the inner cylinder 10). 1 is shown. 4A is a perspective view seen from above the pile removing device 1, FIG. 4B is a perspective view seen from below, and FIG. 4C is a sectional view thereof. The protrusion 13 is located at the upper end of the spiral groove 23. As best shown in FIG. 4C, the lower ends 15b of the pair of holding pieces 15 approach each other, and the pair of holding pieces 15 as a whole are bowl-shaped (or substantially conical surfaces) that open upward. Shape). The opening facing downward of the inner cylinder 10 having a cylindrical shape is substantially closed by the pair of holding pieces 15. The rotation position of the holding piece 15 shown in FIG. 4C is referred to as a “closed position”.

  Thus, when the outer cylinder 20 is at the uppermost position with respect to the inner cylinder 10 (see FIGS. 1A to 1C), the holding piece 15 is at the open position, and the outer cylinder 20 is at the uppermost position with respect to the inner cylinder 10. When in the lower position (see FIGS. 4A to 4C), the holding piece 15 is displaced (rotated) in conjunction with the relative movement of the outer cylinder 20 with respect to the inner cylinder 10 so that the holding piece 15 is located in the closed position. To do. Regardless of whether the holding piece 15 is in the open position, the closed position, or between these positions, the holding piece 15 is accommodated in the outer cylinder 20 and the excavating blade 25 is below the lower end 15b of the holding piece 15. Protrusively. Regardless of the position of the holding piece 15, the outer dimension at the distal ends of the pair of guide pieces 16 projecting outward in the radial direction from the outer peripheral surface of the outer cylinder 20 is equal to or smaller than the outer diameter of the enlarged diameter portion 21.

  When the holding piece 15 is in the open position (see FIG. 1C), the minimum inner dimension of the pair of holding pieces 15 (in this embodiment, the distance between the lower ends 15b of the pair of holding pieces 15) is a pile ( It is larger than the outer diameter of the pile 30) of FIG. Therefore, the pile can enter the inner cylinder 10 through the space between the pair of holding pieces 15 from the opening facing the lower side of the outer cylinder 20.

  On the other hand, when the holding piece 15 is in the closed position (see FIG. 4C), the distance between the lower ends 15b of the pair of holding pieces 15 is smaller than the outer diameter of the pile to be pulled out. Therefore, the pile cannot pass between the pair of holding pieces 15 (see FIG. 5C described later).

  Although the material of each member which comprises the pile punching apparatus 1 is not limited, For example, steel can be used (however, the blade body of the excavation blade 25 is remove | excluded). The inner cylinder 10 and the outer cylinder 20 can be created by cutting a steel pipe into a predetermined shape. The holding piece 15 may be prepared by cutting out a predetermined shape from a steel pipe, or may be prepared by cutting a steel flat plate into a predetermined shape (for example, a substantially isosceles trapezoid) and then bending it with a press. .

  Next, a pile removing operation using the pile removing apparatus 1 will be described.

  FIG. 5A is a diagram showing a state immediately before the start of the pile removing operation. The ground 32 is shown in cross section so that the pile 30 embedded in the ground 32 can be visually recognized. In this invention, there is no restriction | limiting in the kind of pile 30 and well-known piles, such as a steel pile, a concrete pile, a synthetic pile, may be sufficient. The pile 30 is not limited, but is generally an elongated rod-like member having a substantially constant outer diameter. First, as illustrated, the ground surface around the pile 30 is excavated as necessary so that the upper end of the pile 30 is exposed.

  The pile unloader 1 is suspended from the tip of a telescopic boom 34 of the crane vehicle 33 via a rotary drive device (also called an auger) 35. As the rotation drive device 35, a well-known device that can be rotated forward and backward, which is used when drilling the ground, can be used. In this example, the extension pipe 19 is connected to the upper end of the inner cylinder 10 of the pile removing device 1, and the top plate 17 (see FIG. 1A) is connected to the upper end of the extension pipe 19. The extension pipe 19 is a steel pipe having a hollow cylindrical shape having substantially the same inner diameter and outer diameter as the inner cylinder 10. In the present invention, the use of the extension tube 19 is not essential. However, if necessary, one or a plurality of extension pipes 19 are provided between the inner cylinder 10 and the top plate 17 so that the distance between the holding piece 15 and the top plate 17 is longer than the entire length of the pile 30. Intervene. The connecting shaft 18 (see FIG. 1A) protruding from the top plate 17 is chucked on the rotation drive device 35.

  The pile removing device 1 is aligned so as to be coaxial with the pile 30. Using the rotation drive device 35, the inner cylinder 10 (that is, the pile removing device 1) is rotated (forward rotation) in the clockwise direction when viewed from above. Then, the pile removing device 1 is lowered. The excavating blade 25 provided at the lower end of the outer cylinder 20 starts excavating the ground 32. The excavation blade 25 receives a reaction force from the ground 32. Due to this reaction force, the outer cylinder 20 is moved to and maintained at the uppermost position (FIGS. 1A to 1C) with respect to the inner cylinder 10. Therefore, the holding piece 15 is maintained in the open position.

  The pile removing device 1 is further lowered while being kept coaxial with the pile 30. As the pile removing device 1 excavates the ground 32, the pile 30 passes between the pair of holding pieces 15 and enters the inner cylinder 10 from the opening facing the lower side of the outer cylinder 20. The pile 30 and the surrounding ground 32 are edge-cut by the pile removing device 1.

  As shown in FIG. 5B, after digging until the pair of holding pieces 15 are located below the lower end of the pile 30, the rotation of the pile removing device 1 is stopped. The pile 30 is accommodated in the inner cylinder 10 and the extension pipe 19.

  Next, as illustrated in FIG. 5C, the inner cylinder 10 (that is, the pile removing device 1) is rotated (reversely rotated) in the counterclockwise direction when viewed from above using the rotation driving device 35. The excavation blade 25 and the enlarged diameter portion 21 receive a reaction force from the ground 32, and the outer cylinder 20 moves to the lowest position (FIGS. 4A to 4C) with respect to the inner cylinder 10 due to the reaction force. Therefore, the holding piece 15 moves to the closed position. The lower end of the pile 30 is supported by the holding piece 15. While the inner cylinder 10 is rotated in the reverse direction, the pile removing device 1 is raised straight. The pile 30 is lifted together with the pile removing device 1 with its lower end held by the holding piece 15. Since the holding piece 15 is maintained in the closed position, the pile 30 does not fall out of the pile removing device 1.

  After the extension pipe 19 comes to the ground, the rotation is stopped and the extension pipe 19 and the inner cylinder 10 are separated. The upper part of the pile 30 held by the pile removing apparatus 1 is exposed. As shown in FIG. 5D, a wire 38 hung from a crane vehicle 37 different from the above is wound around the pile 30. And as shown to FIG. 5E, the wire 38 is wound up, the pile 30 is raised, and it pulls out from the pile extraction apparatus 1. FIG. Thereafter, the pile removing device 1 is similarly pulled out from the ground 32.

  The above work procedure is an example, and the pile 30 can be pulled out by a method other than the above. For example, when the pile 30 is relatively short, the pile 30 may be pulled out to the ground while being stored in the pile removing device 1, and then the pile 30 may be pulled out from the pile removing device 1.

  As described above, the pile removing device 1 of the present invention is rotated by applying a rotational driving force around the central axis to the inner cylinder 10. When the rotation direction of the inner cylinder 10 is changed, the relative position of the outer cylinder 10 with respect to the inner cylinder 10 is changed, and the opening / closing of the pair of holding pieces 15 is switched in conjunction with this. More specifically, the pair of holding pieces 15 can be maintained in the open position by digging (lowering) while the inner cylinder 10 is rotated forward with respect to the ground 32, and the inner cylinder 10 is reversed with respect to the ground 32. The pair of holding pieces 15 can be maintained in the closed position by retreating (raising) while rotating. In the present invention, no special device such as a hydraulic cylinder is required to open and close the pair of holding pieces 15. For this reason, the structure of the pile removing device 1 of the present invention is simple. This is advantageous for cost reduction of the pile removing device 1.

  Since a hydraulic cylinder is not used, a hydraulic system including a hydraulic power source (hydraulic pump) and hydraulic piping necessary when using the hydraulic cylinder is also unnecessary. Therefore, compared with the case where a hydraulic cylinder is used, the structure of the whole apparatus required for pile removal work can be simplified, and the work accompanying pile removal can be simplified and shortened. This is advantageous for lowering the cost of the entire pile removing operation.

  Further, since the pair of holding pieces 15 can be switched from the open position to the closed position only by reversing the rotation direction of the inner cylinder 10 during excavation and retreat, the work procedure for pile removal is extremely simple. is there. This is advantageous in reducing erroneous operations.

  In the present invention, the guide piece 16 protruding from the holding piece 15 is fitted into a groove 26 provided in the outer cylinder 20 along the circumferential direction. When the outer cylinder 20 moves spirally with respect to the inner cylinder 10, the guide piece 16 moves in the circumferential direction in the groove 26. Thereby, the holding piece 15 can be rotated in conjunction with the outer cylinder 20 with an extremely simple structure.

  In the above-described conventional pile removing device, it is necessary to transmit the vertical movement of the piston of the hydraulic cylinder installed near the upper end of the casing to a pair of gripping pieces installed at the lower end of the casing. For this reason, the power transmission path is long. In order to pull out a long pile, since it is necessary to lengthen the casing accordingly, it is also necessary to lengthen the power transmission path. For this reason, the structure of the pile removing device is further complicated.

  On the other hand, in the present invention, the outer cylinder 20 is disposed so as to accommodate the holding piece 15. For this reason, even if the extension pipe 19 is connected to the inner cylinder 10 according to the length of the pile 30 (see FIG. 5A), the mechanism for rotating the holding piece 15 remains simple and unchanged. Therefore, it is possible to easily cope with a long pile.

  The guide piece 16 is provided substantially at the center of the arcuate upper end edge 15 a of the holding piece 15. Since the distance from the guide piece 16, which is the point of action of the force for rotating the holding piece 15, to the rotation axis of the holding piece 15 (ie, the axis passing through the pair of pins 12), the outer cylinder The holding piece 15 can be rotated only by applying a relatively small force to the holding piece 15. As a result, the holding piece 15 is reliably opened and closed, so that the reliability of the opening and closing operation of the holding piece 15 is improved.

  In the conventional pile removing device described in Patent Document 1 described above, the connecting piece that moves up and down in conjunction with the piston of the hydraulic cylinder rotates the pivot along the rotation axis of the gripping piece, thereby Rotate. In this structure, since the distance from the point of application of the force to the rotating shaft of the gripping piece is extremely short, it is necessary to apply a very large rotational torque to the pivot through the coupling fitting. For this reason, a hydraulic cylinder that generates a very large force is required, and it is necessary to increase the strength of the power transmission mechanism from the hydraulic cylinder to the gripping piece. In the present invention, there is no need to particularly increase the strength around the guide piece 16 or the groove 26 of the outer cylinder 20. This is advantageous for simplification and weight reduction of the structure of the pile removing device 1.

  The above embodiments are merely examples. The present invention is not limited to the above embodiment, and can be modified as appropriate.

  In the above embodiment, the spiral cam groove 23 is provided in the outer cylinder 20 and the cam pin 13 is provided in the inner cylinder 10 in order to move the outer cylinder 20 spirally with respect to the inner cylinder 10. Conversely, a spiral cam groove may be provided on the inner cylinder 10 and a cam pin may be provided on the inner peripheral surface of the outer cylinder 20.

  A cutting blade capable of cutting the pile 30 may be provided at the lower end of the holding piece 15. In this case, if the inner cylinder 10 is reversely rotated in a state where the pile 30 is not completely stored in the pile removing device 1, the pile 30 can be cut with the cutting blade. Thereby, when pulling out the long pile 30, since the pile 30 can be divided | segmented into several and can be pulled out, the lifting load required for a crane can be restrained small.

  The cam groove constituting the spiral cam does not have to be a spiral along the right screw, and may be a spiral along the left screw. In this case, the inner cylinder 10 is rotated counterclockwise when viewed from above during excavation, and is rotated clockwise when viewed from above when retreating.

  A through hole may be provided in at least one (preferably all) of the inner cylinder 10, the outer cylinder 20, and the extension pipe 19 so that the stored pile 30 can be seen.

  The present invention can be widely used as a pile removing device for pulling out a pile embedded in the ground.

1 Pile removal device 10 Inner cylinder 12 Pin (Rotating shaft of holding piece)
15 Protrusion (cam pin)
15 Holding piece 15a Upper edge 15b of holding piece Lower end 16 of holding piece Guide piece 20 Outer cylinder 23 Spiral groove (cam groove)
25 Excavation blade 26 Circumferential groove (guide groove)

Claims (4)

An inner cylinder having a hollow cylindrical shape;
A pair of holding pieces attached to the lower end of the inner cylinder so as to face each other in the diameter direction of the inner cylinder;
An outer cylinder having a hollow cylindrical shape;
A pile removing device comprising a drilling blade provided at the lower end of the outer cylinder,
The pair of holding pieces includes an open position where lower ends of the pair of holding pieces are spaced apart from each other so as to open an opening facing downward of the inner cylinder, and an opening position of the pair of holding pieces facing downward of the inner cylinder. The lower end of the pair of holding pieces can be rotated between the closed positions close to each other,
The outer cylinder is disposed coaxially with the inner cylinder, storing at least the lower end of the inner cylinder and the pair of holding pieces in the outer cylinder,
The outer cylinder is movable spirally within a predetermined range with respect to the inner cylinder,
When the outer cylinder is in the uppermost position with respect to the inner cylinder, the pair of holding pieces are in the open position, and when the outer cylinder is in the lowest position with respect to the inner cylinder, the pair of holding pieces The pile removing device, wherein the pair of holding pieces are interlocked with the movement of the outer cylinder with respect to the inner cylinder so that the pieces are located at the closed position. One of the inner cylinder and the outer cylinder includes a helical cam groove,
The other of the said inner cylinder and the said outer cylinder is a pile removal apparatus of Claim 1 provided with the cam pin inserted in the said cam groove. The outer cylinder includes a guide groove along a circumferential direction,
The holding piece includes a guide piece that fits into the guide groove,
The pile removing device according to claim 1 or 2, wherein when the outer cylinder moves spirally with respect to the inner cylinder, the guide piece moves in the circumferential direction in the guide groove. The guide piece is provided at substantially the center of the upper end edge of the substantially arc shape of the holding piece,
The pile removing device according to claim 3, wherein the rotation axis of the holding piece passes near both ends of the upper end edge.

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