Pull-out device for existing pile

Abstract

To provide a pull-out device for an existing pile capable of reducing excavation resistance comparing to the existing one.SOLUTION: The present invention pulls out an existing pile by rotating a casing using a rotation drive mechanism, digging around the existing pile to advance, cutting an edge between a circumference of the existing pile and soil surrounding the existing pile, and locking a lower part of the existing pile with a locking mechanism arranged on a lower part of the casing. The locking mechanism 7 is provided with: a locking claw 11 locking on the lower part of the existing pile 5; a housing 10 journaling and holding the locking claw 11; a slider plate 10a arranged on the lower part of the housing 10 to make the housing 10 slide in a vertical direction of the casing 2; a guide rail mechanism 15 for guiding the slider plate 10a to slide in the vertical direction of the casing 2; a plurality of fixation means (fixation pieces) 16 for fixing the guide rail mechanism 15 on the casing 2; and a cam body 17 for guiding a lower part of the locking claw 11 to an opening side of the casing 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an existing pile extraction device for extracting existing piles buried in the ground. [Background technology]

[0002] 10 to 12 show a conventional existing pile extraction device 50 disclosed in Patent Document 1. As shown in FIG. 10, the conventional existing pile extraction device 50 includes a rotary drive mechanism (earth auger) 51 at the top for digging while rotating a casing 53, and a cylindrical casing 53 is connected to the bottom of the rotary drive mechanism 51 via a swivel (swivel joint) 52. A tip excavation blade 54 for cutting the edge between the periphery of the existing pile 70 and the surrounding ground is attached to the inner peripheral wall at the lower end of the casing 53, and an outer excavation blade 64 for digging the ground around the casing 53 is attached to the outer peripheral part at the lower end of the casing 53 so that the locking mechanism 55 can easily move down while rotating in the soil. The locking mechanism 55 is provided on the upper outer peripheral side near the outer excavation blade 64, and a locking claw (hooking claw) 55A locks onto the lower end of the existing pile 70 to pull out the existing pile 70.

[0003] The locking claw 55A is connected via a rod 57 to a piston rod of a hydraulic cylinder 56 attached to the upper part of the casing 53. As shown in Figs. 11 to 13, a claw cover 61 is attached to the outside of the casing 53 so as to cover the outside of the locking claw 55A. Therefore, the locking claw 55A is disposed in the internal space of the claw cover 61 and moves up and down within this internal space. Long guide holes 61C are formed in both side plate parts 61A of the claw cover 61 in the vertical direction, and both ends of a rotation shaft (pivot shaft) 62 journaled laterally at the upper end of the locking claw 55A are slidably inserted into the long guide holes 61C. As a result, the locking claw 55A slides up and down along the guide long hole 61C of the claw cover 61 via the pivot shaft 62, and when the locking claw 55A slides downward, it rotates around the pivot shaft 62 due to the action of the cam body 63 as described below, and enters the inside of the casing 53 from the lower part of the locking claw 55A at an inclination.

[0004] As described above, when the locking claw 55A slides downward, it rotates around the pivot shaft 62 because, as shown in Fig. 11, an opening (aperture) 66 is formed at the position where the claw cover 61 is attached to the lower part of the casing 53, and an L-shaped cam body 63 is provided at the lower part of this opening 66. That is, when the piston rod of the hydraulic cylinder 56 protrudes downward and the locking claw 55A slides downward within the claw cover 61 along the long guide hole 61C by the rod 57, the outer surface of the lower part of the locking claw 55A abuts against the cam body 63 and rotates around the pivot shaft 62, and enters the opening 66 into the inside of the casing 53 while inclining. When the casing 53 has been dug down until the locking claws 55A are positioned just below the existing pile 70, the locking claws 55A are inserted into the inside of the casing 53 as described above, and the locking claws 55A lock the lower part of the existing pile 70.Then, by lifting the entire casing 53, the existing pile 70 can be pulled out upward. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP2019-194422A Summary of the Invention [Problem to be solved by the invention]

[0006] In order for the casing 53 to rotate and dig into the soil, it is necessary for the casing 53 to rotate smoothly. However, in the conventional existing pile extraction device 50 disclosed in Patent Document 1, the locking mechanism 55 may hinder rotation in the soil, preventing the casing 53 from rotating smoothly. This is because the locking mechanism 55 must be made large, which increases the resistance to the rotation of the casing 53 in the soil.

[0007] The reason why the locking mechanism 55 has to be enlarged is that, as shown in FIG. 12, when the locking claw 55A is locked to the bottom of the existing pile 70 and the casing 53 is pulled up, the load of the existing pile 70 is applied to the rotating shaft 62, and the load is also applied to the claw cover 61. For this reason, the claw cover 61 had to be large and sturdy enough to withstand the load of the existing pile 70. Moreover, since both ends of the rotating shaft 62 are structured to slide along the guide long holes 61C drilled in the side plate portion 61A of the claw cover 61, the side plate portion 61A must be thick and sturdy, and for that reason, the claw cover 61 has to be enlarged, and as shown in FIG. 13, the protruding dimension H of the claw cover 61 outward from the casing 53 is large. As a result, when the casing 53 is rotated while digging, the resistance of the claw cover 61 against the soil also increases, so there was a problem that the output of the rotation drive mechanism 51 that rotates the casing 53 had to be increased.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide an existing pile extraction device that allows the locking mechanism to slide up and down and can keep the dimension of the locking mechanism protruding outward from the casing small. [Means for solving the problem]

[0009] The present invention is an existing pile extraction device that rotates a casing using a rotary drive mechanism, excavates the soil around the existing pile to separate the periphery of the existing pile from the soil surrounding it, and engages the lower part of the existing pile with a locking mechanism provided at the bottom of the casing to pull out the existing pile. The locking mechanism comprises a locking claw that locks onto the lower part of the existing pile, a housing that axially supports and holds the locking claw, a slider plate provided at the bottom of the housing and slides the housing in the vertical direction of the casing, a guide rail mechanism that slides and guides the slider plate in the vertical direction of the casing, a fixing means for fixing the guide rail mechanism to the casing, and a cam body that guides the lower part of the locking claw toward the opening side of the casing. Effect of the Invention

[0010] With the above-described configuration, the present invention allows the dimension by which the locking mechanism protrudes outward from the casing to be kept small, thereby allowing the resistance of the locking mechanism to the soil to be kept small when digging while rotating the casing. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a front view showing an existing pile extraction device according to the present invention; [Diagram 2] A perspective view from below of the locking mechanism of the existing pile extraction device of the present invention. [Diagram 3] FIG. 2 is a partial cross-sectional view of the locking mechanism of the present invention. [Figure 4] A top cross-sectional view of the locking mechanism of the present invention. [Diagram 5] FIG. 2 is a partial longitudinal cross-sectional view of the locking mechanism of the present invention. [Figure 6] A diagram showing the state of use of the locking mechanism of the present invention. [Figure 7] A diagram showing the state of use of the locking mechanism of the present invention. [Figure 8] FIG. 1 is a partial front view of a high-pressure water pipe and a high-pressure water nozzle according to the present invention; [Figure 9] FIG. 2 is a partial vertical cross-sectional view of the high-pressure water pipe and the high-pressure water nozzle of the present invention. [Figure 10] Overall front view showing a conventional existing pile extraction device [Figure 11] A longitudinal cross-sectional view of the lower end of a conventional pile extraction device [Figure 12] A longitudinal cross-sectional view of the lower end of a conventional pile extraction device [Figure 13] A plan sectional view of a conventional locking mechanism DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Outline of the existing pile extraction device) An existing pile extraction device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall front view of the existing pile extraction device of the present invention. This existing pile extraction device 1 is equipped with a cylindrical casing 2 which constitutes a main component, and a rotary drive mechanism (earth auger) 4 is provided on the upper part of this casing 2 via a swivel 3. The casing 2 is excavated while rotating by the rotary drive mechanism 4, and acts to cut the edge between the existing pile 5 and the surrounding ground so that the existing pile extraction device 1 can extract the existing pile 5. The casing 2 is configured by connecting, for example, an upper casing 2a, a middle casing 2b, and a lower casing 2c, but the casing 2 is not limited to such a divided configuration.

[0013] A number of tip excavation blades 6 and outer excavation blades 60 for digging the ground are attached to the lower end 2d of the casing. In addition, locking mechanisms 7 for pulling out existing piles 5 are provided on the casing 2 at symmetrical positions on the upper outer periphery near the outer excavation blades 60. Hydraulic cylinders 8 are attached to the upper part of the casing 2 in correspondence with each locking mechanism 7. The piston rods of the hydraulic cylinders 8 and the locking mechanisms 7 are connected by connecting rods 9, and the extension and contraction of the piston rods of the hydraulic cylinders 8 causes the housings 10 and locking claws 11 of the locking mechanisms 7 to slide up and down relative to the casing 2.

[0014] In addition, a hydraulic passage (not shown) for sending oil to the hydraulic cylinder 8 is formed inside the swivel 3, and a hydraulic connection pipe 12 is connected to this hydraulic passage, and oil from the base machine is sent to the hydraulic cylinder 8 through the hydraulic passage and the hydraulic connection pipe 12. Furthermore, a high-pressure water passage (not shown) is formed inside the swivel 3, and a high-pressure water pipe 13 is connected to this high-pressure water passage. The high-pressure water pipe 13 and the high-pressure water nozzle 13a at the lower end of this high-pressure water pipe 13 will be described later with reference to the drawings. In addition, the hydraulic cylinder 8, the connecting rod 9, and the locking mechanism 7 are provided in two units on the outer periphery of the casing 2, but three or four or more units may be provided. In order to install multiple hydraulic cylinders 8, the connecting rod 9, and the locking mechanism 7 in this way, they are arranged at equal intervals (every 180 degrees in the case of two, every 120 degrees in the case of three, and every 90 degrees in the case of four) on the outer periphery of the cylindrical casing 2. Only one high-pressure water pipe 13 is arranged in the vertical direction of the casing 2, but this may also be two or more. As shown simply in FIG. 1, the casing 2 is also provided with screws 14 on the outer periphery of the lower part thereof to better drill the casing 2 downward.

[0015] (locking mechanism) 2 to 4 show a locking mechanism 7 that locks the lower part of an existing pile 5 and pulls out the existing pile 5. The locking mechanism 7 is composed of a locking claw 11 that locks the lower part of the existing pile 5, a housing 10 that pivotally supports and holds the locking claw 11, a slider plate 10a that is provided at the lower part of the housing 10 and slides the housing 10 in the up-down direction of the casing 2, a guide rail mechanism 15 that guides the slider plate 10a by sliding it in the up-down direction of the casing 2, a fixing means 16 that fixes the guide rail mechanism 15 to the casing 2, and a cam body 17 that guides the lower part of the locking claw 11 to the opening 2E side of the casing 2. These members will be described below.

[0016] The locking claw 11 is made of thick steel material, and an inclined surface 11a is formed at the bottom of the cubic locking claw 11, which inclines the locking claw 11 toward the casing 2 by a cam body 17. A rotating shaft 18 is inserted into an axial hole 11b formed at the base end (upper part) of the locking claw 11, and the locking claw 11 rotates forward and backward around the rotating shaft 18. Both ends of the rotating shaft 18 are fixed to fixing holes 10c drilled in both side plates 10b of the housing 10 described below, and the locking claw 11 is bridged across both side plates 10b of the housing 10. As described above, an opening 2E is formed in the wall of the casing 2 facing the locking claw 11 so that the locking claw 11 can rotate and enter the casing 2 without any hindrance.

[0017] Housing: The housing 10 is made up of three thick plates and is formed in a substantially U-shape as shown in FIG. 2. The frame of this embodiment is made up of the side plate 10b, which is made up of two plates arranged in parallel, and a connecting plate 10d that connects the upper ends of the side plates 10b, and the upper ends of both side plates 10b are welded to the connecting plate 10d. As described above, the side plate 10b is provided with fixing holes 10c through which both ends of the rotating shaft 18 are inserted and fixed. The connecting plate 10d is also connected to the piston rod of the hydraulic cylinder 8 via the connecting rod 9. The surface of the housing 10 facing the casing 2 is open without a plate, so that the locking claw 11 can rotate and enter the opening 2E of the casing 2. The outside of the housing 10 (the surface far from the opening 2E of the casing) is also open without a plate. This allows the thickness h of the existing pile extraction device 1 to be thin (see FIG. 4). In this embodiment, the housing 10 is composed of three separate plates, but the number of plates is not limited to three, and the housing 10 may be an integrated U-shaped structure.

[0018] Slider plate: The slider plate 10a is provided at the bottom of both side plates 10b of the housing 10. The slider plate 10b may be integral with the side plates 10b of the housing 10 or may be separate. As shown in Figs. 2 to 4, in this embodiment, the width of the slider plate 10a is the same as the width of the guide rail 15a of the guide rail mechanism 15, and is about twice as wide as the width of the side plates 10b. The length of the slider plate 10a is slightly longer than the length of the side plates 10b. As shown in Fig. 4, the inner surface of the slider plate 10a and the inner surface of the side plates 10b are flush with each other, and the slider plate 10a and the locking claw 11 are configured not to interfere with each other when the locking claw 11 turns toward the opening 2E of the casing 10.

[0019] Guide rail mechanism: In this embodiment, the guide rail mechanism 15 is composed of the guide rail 15a on which the slider plate 10a at the bottom of the housing 10 slides up and down, and a guide member 15b that holds the slider plate 10a slidably with a gap G between the guide rail 15a and the guide member 15b. As shown in FIG. 4, the outward protrusion dimension of the guide rail mechanism 15 and a fixing means 16 (described later) from the casing 2 is smaller than the outward protrusion dimension of the locking claw 11. As shown in FIG. 2 and FIG. 3, the guide rail 15a is a long flat plate-shaped plate body welded to the casing 2 so as to protrude from the side edge of the opening 2E of the casing 2 toward the center of the opening 2E. The slider plate 10a slides up and down on the guide rail 15a. As shown in Fig. 4, the inner surface of the guide rail 15a and the inner surface of the slider plate 10a are flush with each other, and the locking claw 11 is configured not to interfere with the slider plate 10a and the guide rail 15a when the locking claw 11 rotates toward the opening 2E. The length of the guide rail 15a is set to a length that allows the slider plate 10a to slide so that the locking claw 11 can rotate from the standby position as shown in Fig. 6 to the opening 2E of the casing 2 as shown in Fig. 7 and lock the lower part of the existing pile 5.

[0020] As shown in Figs. 2 to 4, the guide member 15b is a long steel material with an inverted L-shaped cross section, and between the guide rail 15a and the guide member 15b there is a gap G which is slightly larger than the thickness of the slider plate 10a and opens to the locking claw 11 side, and guides the slider plate 10a in the up-down direction. The guide member 15b is welded at its lower end in a state where it is erected on the casing 2. Note that the guide rail mechanism 15 is composed of the guide rail 15a and the guide member 15b, but the guide rail mechanism 15 is not limited to this configuration, and may be a channel-shaped steel material with a U-shaped cross section in which the guide rail 15a and the guide member 15b are integrally combined.

[0021] Fixing means: The fixing means 16 in this embodiment is a small mounting member in an inverted L-shape, and serves to fix the guide member 15b to the casing 2. In this embodiment, as shown in Figs. 2 and 3, five fixing pieces are arranged at equal intervals to fix the guide member 15b to the casing 2. The shape of the fixing pieces is not limited to this shape, and the fixing means 16 is not limited to the fixing pieces shown in Figs. 2 and 3. For example, the fixing means 16 may be formed by welding the guide rail 15a and the guide member 15b of the guide rail mechanism 15 to the casing 2 by welding. Also, as described above, in the case where the guide rail mechanism 15 is a channel-shaped steel material having a U-shaped cross section in which the guide rail 15a and the guide member 15b are integrally combined, this steel material may be welded to the casing 2 or fixed with bolts.

[0022] Cam body: The cam body 17 is formed in a triangular prism shape, and a single tapered surface 17a is formed on the inside of the cam body 17 for inserting the locking claw 11 into the inside of the casing 2. The outer surface of the lower part of the locking claw 11 is also formed with an inclined surface 11a that abuts against the tapered surface 17a. The cam body 17 is provided at the lower end of the opening 2E of the casing 2, and the housing 10 and the locking claw 11 are slid downward by the hydraulic cylinder 8 via the connecting rod 9, so that the inclined surface 11a of the locking claw 11 descends while sliding against the tapered surface 17a of the cam body 17, and the locking claw 11 enters the inside of the casing 2 from the opening 2E while rotating around the rotating shaft 18.

[0023] (High pressure water nozzle) As described above, a high-pressure water passage (not shown) is formed inside the swivel 3, and the high-pressure water pipe 13 is connected to this high-pressure water passage. As shown in Fig. 1, this high-pressure water pipe 13 is laid along the casing 2 to the lower part. As shown in Figs. 8 and 9, a high-pressure water nozzle 13a is attached to the lower end of this high-pressure water pipe 13. High-pressure water is sprayed from this high-pressure water nozzle 13a into the lower part of the casing 2 to promote softening of the ground being excavated by the tip excavation blade 6 and the outer excavation blade 60, and promotes cutting the edge between the periphery of the existing pile 5 and the surrounding ground. The nozzle of the high-pressure water nozzle 13a opens in the lateral direction, and a rubber packing 13b is attached to this nozzle, so that pebbles and mud do not enter the high-pressure water nozzle 13a.

[0024] (action) Next, the operation of the above-mentioned configuration will be described. Although not shown, the existing pile extraction device 1 according to the embodiment of the present invention is configured by attaching a leader to a crawler crane via a backstay, and supporting the existing pile extraction device 1 of the present invention on the leader. When performing construction to extract an existing pile 5 using the existing pile extraction device 1, the existing pile extraction device 1 is set on top of the existing pile 5 driven into the ground. At that time, the piston rod of the hydraulic cylinder 8 is contracted, and the locking claw 11 in the housing 10 is positioned so as to extend up and down on the side of the casing 2 as shown in FIG. 6, so that it does not enter the opening 3E of the casing 2.

[0025] To excavate the existing pile extraction device 1, the bottom of the casing 2 is fitted onto the head of the existing pile 5, the rotary drive mechanism 4 is started to rotate the casing 2, and the excavation blade 6 excavates the soil around the existing pile 5. When digging, high-pressure water is sprayed from the high-pressure water nozzle 13a into the casing 2 to soften the soil, and the excavation blade 6 excavates the soil around the existing pile 5. The existing pile extraction device 1 excavates the soil while being pushed downward by the leader. The screw 14 attached to the outer periphery of the lower part of the casing 2 also serves to dig down the casing 2.

[0026] When the casing 2 is dug down to a position where the locking claw 11 is below the existing pile 5, the existing pile 5 is cut off from the surrounding soil. In this state, the piston rod of the hydraulic cylinder 8 is pushed downward to push the housing 10 down via the connecting rod 9, and the slider plate 10a at the bottom of the housing 10 slides downward by the guide rail mechanism 15. The locking claw 11 supported on the rotating shaft 18 of the housing 10 also descends together with the housing 10. As the locking claw 11 descends, the locking claw 11 rotates around the rotating shaft 18 while the inclined surface 11a slides against the tapered surface 17a of the cam body 17, as shown in FIG. 7, and is guided to the opening 2E side of the casing 2. When the locking claw 11 penetrates deeply into the opening 2E, the locking claw 11 locks the bottom of the existing pile 5 as shown in FIG. 7. In this state, the existing pile extraction device 1 is pulled up by the leader, and the existing pile 5 inside the casing is pulled upward together with the casing 2.

[0027] The existing pile extraction device 1 of the present invention is configured such that the thin slider plate 10a provided at the bottom of the housing 10 slides in the gap G of the guide rail mechanism 15, so that the outward protruding dimension h of the frame body 4 can be kept small, as shown in Fig. 4. That is, the thin slider plate 10a is provided at the bottom of the housing 10 having a substantially rectangular parallelepiped shape, and a part of the slider plate 10a is configured to protrude from the side of the housing 10, and the protruding part of the slider plate 10a is fitted into the gap G of the guide rail mechanism 15 so that the slider plate 10a can slide and move on the guide rail mechanism 15. With the above configuration, the slider plate 10a and the guide rail mechanism 15 do not protrude outward from the housing 10, so that the protruding dimension h of the locking mechanism 7 can be made small.

[0028] For example, the outward protrusion dimension H of the claw cover 61 from the casing 53 in the conventional configuration was approximately 132 mm, whereas the outward protrusion dimension h of the locking mechanism 7 in the above configuration could be significantly reduced to approximately 75 mm. As a result, the protrusion dimension h of the locking mechanism 7 could be kept small, and the output of the rotation drive mechanism 4 could also be kept small.

[0029] As for the structure for supporting the locking claw 11, the locking claw 11 is rotatably supported on a pivot shaft 18 that is suspended between both side plates 10b of the housing 10. This makes it possible to make the structure of the locking mechanism 7 stronger than the conventional locking claw 55A that slides through the guide long hole 61C. Therefore, even if the structure is made smaller, the locking claw 11 can withstand the weight applied when the existing pile 5 is pulled out. [Industrial Applicability]

[0030] The present invention can be widely applied to existing pile extraction devices that extract existing piles buried in the ground. [Explanation of symbols]

[0031] 1. Existing pile extraction device 2 Casing 3 Swivel 4 Rotation drive mechanism (earth auger) 5 Existing piles 6. Tip digging blade 60 outer drilling blade 7 Locking mechanism 8 Hydraulic Cylinders 9 Connecting rod 10. Housing 10a slider plate 10b side plate 10c fixing hole 10d connecting plate 11 Locking claw 11a Slope 11b Shaft hole 12 Hydraulic connecting pipe 13 High pressure water piping 13a High pressure water nozzle 14 Screw 15 Guide rail mechanism 15a Guide rail 15b Guide member 16 Fixing means 17 Cam body 17a Tapered surface 18 Rotating shaft G Gap

Claims

1. The device rotates a casing using a rotary drive mechanism, excavates the soil around the existing pile, and separates the periphery of the existing pile from the surrounding soil. The device engages the lower part of the existing pile using a locking mechanism provided at the bottom of the casing, and pulls out the existing pile. The locking mechanism is an existing pile extraction device that includes a locking claw that locks onto the bottom of the existing pile, a housing that supports and holds the locking claw, a slider plate that is provided on the bottom of the housing and slides the housing in the vertical direction of the casing, a guide rail mechanism that guides the slider plate by sliding it in the vertical direction of the casing, a fixing means that fixes the guide rail mechanism to the casing, and a cam body that guides the bottom of the locking claw toward the opening side of the casing.

2. The existing pile extraction device described in claim 1, characterized in that the guide rail mechanism is composed of a guide rail on which a slider plate provided at the bottom of the housing rests and slides up and down, and a guide member that holds the slider plate slidably by providing a gap between the guide rail and the guide member.

3. 3. An existing pile extraction device as described in claim 1 or claim 2, characterized in that a high-pressure water pipe is piped along the casing to the lower part, a high-pressure water nozzle is attached to the lower end of the high-pressure water pipe, and high-pressure water is sprayed from the high-pressure water nozzle into the lower part of the casing to promote softening of the ground and promote cutting of the edge between the periphery of the existing pile and the surrounding ground.

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