JP2000154541A - Pulling-out device for existing pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulling-out device for an existing pile capable of securely pulling out all the existing piles by confirming the projecting operation of a chuck claw into a casing and protecting a hydraulic cylinder for operating chuck claw. SOLUTION: This pulling-out device is provided with a cylindrical casing 3 which is connected with a driving machine 1 and is driven in an existing pile 6 and a chuck claw 4 attached to a lower part of the easing 3 in such a way that it protrudes downward more than a lower end of the existing pile 6 in the easing 3 due to the drive of a hydraulic cylinder 5. The hydraulic cylinder 5 is attached to an upper part of the casing 3 so that a worker can see this expansion and shrinkage conditions directly on the ground, and a lower end part of a rod 13 of the hydraulic cylinder 5 and the chuck claw 4 are mutually connected by a connection rod 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for pulling an existing pile buried underground.

[0002]

2. Description of the Related Art A method for pulling out an existing pile is disclosed, for example, in Japanese Patent Publication No. 3-57247. In this case, if a long time has passed since the existing pile was buried in the ground, the tensile strength has dropped significantly due to corrosion etc., and it was broken off when it was pulled out. The method of pulling out existing piles to solve the problem is described. The pulling method is as follows: a cylindrical casing surrounding the existing pile is driven into the casing so that the lower end of the casing is located below the lower end of the existing pile, and soil around the existing pile in the casing is washed with water or bentonite. After making the locking projection attached to the lower end of the casing project toward the inside of the casing, the pulling force is applied to the casing to contact the lower end of the existing pile. A method of pulling out an existing pile by applying a push-up force to the existing pile with a projection. According to this method, an existing pile whose tensile strength is greatly reduced can be pulled out entirely. .

[0003]

However, in the above-mentioned method of pulling out the existing pile, a hydraulic cylinder is employed for operating the locking projection, and the hydraulic cylinder is provided at the lower end of the casing similarly to the locking projection. Is attached to
In this case, even if the locking projection is projected toward the inside of the casing after driving the casing, the projected state cannot be confirmed on the ground, so the locking projection does not reach the lower end of the existing pile, or Existing piles may be pulled out without contacting the lower end of the piles, and the intended purpose of pulling out all the existing piles may not be achieved. Further, there is a problem that the hydraulic cylinder attached to the lower end of the casing is easily damaged or damaged due to frictional resistance with earth and sand when the casing is driven.

The present invention has been made in order to solve such a problem. It is an object of the present invention to make it possible to confirm the operation of chuck claws projecting into a casing, thereby completely pulling out existing piles. An object of the present invention is to provide an existing pile pulling-out device which can complete the operation and can protect a hydraulic cylinder for operating the chuck jaws.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a cylindrical casing connected to a driving machine and having an inner diameter larger than the maximum outer diameter of an existing pile, and a casing driven by a hydraulic cylinder below the casing. In an existing pile pulling device provided with a chuck claw mounted so as to protrude into the inside, the hydraulic cylinder is mounted on an upper portion of the casing, and a rod end of the hydraulic cylinder and the chuck claw are connected to a connecting rod. It is characterized by being connected by.

The chuck pawl has an arc-shaped cam groove,
This cam groove is inserted through a shaft fixed to the lower portion of the casing, and the chucking claw retreats to a substantially vertical position outside the casing when the connecting rod is raised by the contraction operation of the hydraulic cylinder. When the connecting rod is lowered by the elongating operation, the chuck pawl can be projected into the casing in a substantially horizontal posture.
In the casing, a pipe for ejecting a muddy agent such as water or bentonite into and out of the lower end of the casing can be laid vertically.

[0007]

[Function] Since the hydraulic cylinder is mounted on the upper part of the casing, the extension state of the hydraulic cylinder can be clearly confirmed on the ground when the chuck is driven into the casing after driving the casing against the existing pile. This confirmation makes it possible to know whether or not the chuck pawl has completely protruded below the lowermost end of the existing pile. Therefore, it is possible to prevent the existing pile from being pulled out while the chuck claw does not protrude below the lowermost end of the existing pile, that is, the existing pile being torn off in the middle and being pulled out while leaving the lower part thereof.

[0008] As described above, the entire existing pile can be pulled out by projecting the chuck claw below the lowermost end of the existing pile. However, when the entire pile is pulled out, the tensile strength of the existing pile decreases with the passage of a long period of time. Not only those that do not have an integrated pile, but also existing piles where the pillars, bulbs, and points are not integrated, such as pedestal piles, which are a type of penetrating cast-in-place concrete piles, all of them up to the lowest point Can be pulled out.

The hydraulic cylinder mounted on the upper part of the casing can be protected from earth pressure without receiving the resistance of earth and sand when driving the casing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an existing pile pulling device according to the present invention will be described with reference to the drawings. In FIG. 1, the present apparatus uses an earth auger as a driving machine 1 in the illustrated example, a casing 3 having an upper end detachably connected to the auger shaft 2, and a plurality of casings 3 attached to a lower end portion of the casing 3. It comprises a plurality of chuck claws 4 and a hydraulic cylinder 5 mounted on the upper part of the casing 3 for operating the chuck claws 4.

The casing 3 is formed in a cylindrical shape made of a steel pipe or the like having an inner diameter larger than the maximum outer diameter of the existing pile 6, and has a cutting edge 7 attached to a lower end.

As shown in FIG. 4 and FIG.
Is formed of a steel material or the like, and has an arc-shaped cam groove 8 which is formed in an arcuate edge 4a and a straight edge 4b in a tapered, rear-end circular boat shape. The chuck pawl 4 is provided with a shaft 11, which is mounted between the bearings 10 fixed to the outside of the opening 9 near the lower end of the casing 3.
The cam groove 8 is inserted into the casing 3 so as to substantially vertically extend outside the opening 9 of the casing 3 (see FIG. 5).
Attached so as to be able to move back and forth in the vertical direction around the shaft 11 over a projecting posture (see FIG. 6) that projects substantially horizontally from the opening 9 into the casing 3.

As shown in FIGS. 2 and 3, the upper end of the hydraulic cylinder 5 is pivotally connected to a supporting projection 12 protruding from the upper part of the casing 3 and extends and contracts from the lower end of the hydraulic cylinder 5. A lower end of a flexible cylinder rod 13;
Joint 1 pivotally connected to the rear end of the chuck claw 4
4 are connected by a connecting rod 15 (see FIGS. 4 and 5). The lower end of the cylinder rod 13 and the upper end of the connection rod 15 are connected by a pivot 16 so that the hydraulic cylinder 5 can extend and contract straight in the up and down direction, and a vertical groove 17 in the up and down direction is formed in the casing 3. A pair of guides 18 is fixed, and both ends of the pivot 16 are slidably fitted in the longitudinal grooves 17, 17 so that the cylinder rod 13 is regulated so as to move vertically up and down straight. I have. The connecting rod 15 is inserted into a guide 23 fixed to the casing 3 so as to be vertically movable. When the cylinder rod 13 of the hydraulic cylinder 5 is contracted, the chuck pawl 4 is pulled upward by the connecting rod 13 and retreats from the opening 9 to the outside of the casing 3 in a substantially vertical posture (see FIG. 5). Is extended, the chuck claw 4 is pushed down by the connecting rod 13 and projects from the opening 9 into the casing 3 in a substantially horizontal posture (see FIG. 6).

As shown in FIG. 1, the casing 3 is provided with a pipe 19 for jetting a muddy agent such as water or bentonite in a vertical direction. The lower end 3 faces the opening 20 provided between the chuck claws 4 and 4.

Next, a procedure for pulling out the existing pile 6 using the pulling device having the above-described structure will be described. First, by excavating the ground surface G near the upper end of the existing pile 6 buried underground, the upper end of the existing pile 6 is exposed and its position is confirmed.
Incidentally, the existing pile 6 shown in FIG. 1 and FIG.
This is a pedestal pile in which b and the point 6c are not integrated.

Thus, the casing 3 is driven into the existing pile 6 by the driving machine 1 as shown in FIG. The casing 3 is driven to rotate by a driving machine 1 composed of an earth auger, and is driven into the soil while being digged by a digging blade 7. At this time, a muddy agent such as water or bentonite passes through the pipe 19 and is sent to the lower end of the casing 3, and is ejected from the nozzle 19 a at the tip of the pipe 19 to muddy the soil inside and outside the lower end of the casing 3. Thereby, the casing 3 reduces the frictional resistance with the earth and sand, so that the casing 3 can be easily driven. The driving of the casing 3 is performed to such a depth that the lower end of the casing 3 is about 1 m below the lower end of the existing pile 6.

After the driving, the hydraulic cylinder 5 is extended as shown in FIG. 2B, and the chuck pawl 4 is projected through the connecting rod 15 into the casing 3 as shown in FIG. At this time, whether or not the chuck pawl 4 has sufficiently protruded into the casing 3 can be confirmed by directly viewing the extension length of the rod 13 of the hydraulic cylinder 5 on the ground. After the chuck claw 4 is completely protruded, when a lifting force is applied to the casing 3 by the driving machine 1, the lifting force is applied to the existing pile 6 by the chuck claw 4 abutting on the lowermost end of the existing pile 6, and the casing 3 Can be pulled out together with the existing pile 6 and earth and sand in the casing 3.

As described above, the rod 1 of the hydraulic cylinder 5
Since it is possible to confirm whether or not the chuck claw 4 has sufficiently protruded into the casing 3 by directly looking at the extension state of the ground 3 on the ground, it is possible to confirm that the chuck claw 4 is insufficiently protruding in the middle of the existing pile 6. There is no problem of being pulled out, and the whole up to the lowermost point 6c can be reliably pulled out. When the cylinder rod 13 expands to the maximum, this can be detected by a sensor and a lamp, a buzzer, or the like can be operated to make it easier to confirm the expanded state of the cylinder rod 13 more reliably.

After the pull-out, when the hydraulic cylinder 5 is contracted as shown in FIG. 2A, the chuck pawl 4 withdraws out of the casing 3 via the connecting rod 15 as shown in FIG. The existing pile 6 and earth and sand are extracted downward from the casing 3 by its own weight. At this time, the existing pile 6 and the earth and sand in the casing 3 are smoothly extracted in order to reduce friction between the inner peripheral surface of the casing 3 and the mudified earth and sand.

According to the chuck mechanism having the plurality of chuck claws 4 having the above-described structure, the existing pile 6 can be gripped even in the middle. Therefore, it is not necessary to pull out the entire existing pile 6, and if only the upper part of the existing pile 6, for example, only the pillar 6 a of the illustrated existing pile 6 is to be pulled out, the middle of the pillar 6 a is required. It is also possible to grab and pull out. If the length of the existing pile 6 is not known, as shown in FIG. it can.

In order to confirm the upper end of the existing pile 6 before driving the casing 3, it is necessary to excavate deeply when the upper end of the existing pile 6 is deeper than the ground surface. In this case, it is necessary to protect the surface ground because a driving machine cannot be arranged close to the location or affects a building or the like adjacent to the location. For this purpose, a stand pipe 21 having an inner diameter larger than the maximum outer diameter of the casing 3 is driven into the surface layer G as shown in FIG. The earth and sand inside is excavated with a backhoe and discharged. After that, the casing 3 is connected to the stand pipe 2
1 and driven into the ground to surround the existing pile 6
Thereafter, the casing 3 can be pulled out together with the existing pile 6 by performing the same operation as described above.

In the above embodiment, an earth auger is used as the drawing machine 1, but a vibro hammer can be used instead. In this case, the upper end of the casing 3 is detachably connected to the lower end of the vibrohammer.

[0023]

According to the present invention, since the hydraulic cylinder used to operate the chuck pawl into the casing is mounted on the upper part of the casing, the hydraulic cylinder receives the resistance of earth and sand even when the casing is driven. This has the advantage that not only the protection can be achieved without any problem, but also the chuck pawls can be easily confirmed to protrude into the casing, and the existing pile can be completely pulled out.

[Brief description of the drawings]

FIG. 1 is a front view showing a state in which an existing pile pulling device is driven into the ground.

FIG. 2A is a front view showing a hydraulic cylinder attached to a casing of a drawing device in a contracted state, and FIG. 2B is a front view showing the hydraulic cylinder in an extended state.

FIG. 3 is a view taken in the direction of arrow C in FIG.

FIG. 4 is a front view showing a chuck claw attached to a casing of the drawing device in a retracted state.

FIG. 5 is a side view showing a chuck claw attached to a casing of the drawing device in a retracted state.

FIG. 6 is a side view showing a chuck claw attached to a casing of the drawing device in a protruding state.

FIG. 7 is an explanatory diagram showing an example of a driving process of the drawing device.

FIG. 8 is a front view showing a protection state of a surface ground to be constructed before pulling out an existing pile.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Driving machine 3 Casing 4 Chuck claw 5 Hydraulic cylinder 6 Existing pile 8 Cam groove 11 Shaft 13 Cylinder rod 15 Connecting rod 19 Piping

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[Procedure amendment]

[Submission date] December 28, 1999 (1999.12.
28)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Pulling device for existing pile

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for pulling an existing pile buried underground.

[0002]

2. Description of the Related Art A method for pulling out an existing pile is disclosed, for example, in Japanese Patent Publication No. 3-57247. In this case, if a long time has passed since the existing pile was buried in the ground, the tensile strength has dropped significantly due to corrosion etc., and it was broken off when it was pulled out. The method of pulling out existing piles to solve the problem is described. The pulling method includes driving a cylindrical casing surrounding the existing pile to a depth where the lower end of the casing is located below the lower end of the existing pile, and removing soil around the existing pile in the casing with water or bentonite. After making the locking projection attached to the lower end of the casing project toward the inside of the casing, the pulling force is applied to the casing to contact the lower end of the existing pile. A method of pulling out an existing pile by applying a push-up force to the existing pile with a projection. According to this method, an existing pile whose tensile strength is greatly reduced can be pulled out entirely. .

[0003]

However, in the above-mentioned method of pulling out the existing pile, a hydraulic cylinder is employed for operating the locking projection, and the hydraulic cylinder is provided at the lower end of the casing similarly to the locking projection. Is attached to
In this case, even if the locking projection is projected toward the inside of the casing after driving the casing, the projected state cannot be confirmed on the ground, so the locking projection does not reach the lower end of the existing pile, or Existing piles may be pulled out without contacting the lower end of the piles, and the intended purpose of pulling out all the existing piles may not be achieved. Further, there is a problem that the hydraulic cylinder attached to the lower end of the casing is easily damaged or damaged due to frictional resistance with earth and sand when the casing is driven.

The present invention has been made in order to solve such a problem. It is an object of the present invention to make it possible to confirm the operation of chuck claws projecting into a casing, thereby completely pulling out existing piles. An object of the present invention is to provide an existing pile pulling-out device which can complete the operation and can protect a hydraulic cylinder for operating the chuck jaws.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a cylindrical casing connected to a driving machine and having an inner diameter larger than the maximum outer diameter of an existing pile, and a casing driven by a hydraulic cylinder below the casing. In an existing pile pulling device provided with a chuck claw mounted so as to protrude into the inside, the hydraulic cylinder is mounted on an upper portion of the casing, and a rod end of the hydraulic cylinder and the chuck claw are connected to a connecting rod. With the above hydraulic cylinder
When the connecting rod is raised by the contraction operation, the
The hook claw retreats out of the casing to a substantially vertical position,
The connecting rod is lowered by the extension operation of the hydraulic cylinder
As a result, the chuck claws are substantially horizontal in the casing.
It is characterized in that it protrudes into a posture .

[0006] In the casing, pipes for ejecting a muddy agent such as water or bentonite into and out of the lower end of the casing can be laid up and down.

[0007]

[Function] Since the hydraulic cylinder is mounted on the upper part of the casing, the extension state of the hydraulic cylinder can be clearly confirmed on the ground when the chuck is driven into the casing after driving the casing against the existing pile. This confirmation makes it possible to know whether or not the chuck pawl has completely protruded below the lowermost end of the existing pile. Therefore, it is possible to prevent the existing pile from being pulled out while the chuck claw does not protrude below the lowermost end of the existing pile, that is, the existing pile being torn off in the middle and being pulled out while leaving the lower part thereof.

[0008] As described above, the entire existing pile can be pulled out by projecting the chuck claw below the lowermost end of the existing pile. However, when the entire pile is pulled out, the tensile strength of the existing pile decreases with the passage of a long period of time. Not only those that do not have an integrated pile, but also existing piles where the pillars, bulbs, and points are not integrated, such as pedestal piles, which are a type of penetrating cast-in-place concrete piles, all of them up to the lowest point Can be pulled out.

The hydraulic cylinder mounted on the upper part of the casing can be protected from earth pressure without receiving the resistance of earth and sand when driving the casing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an existing pile pulling device according to the present invention will be described with reference to the drawings. In FIG. 1, the present apparatus uses an earth auger as a driving machine 1 in the illustrated example, a casing 3 having an upper end detachably connected to the auger shaft 2, and a plurality of casings 3 attached to a lower end portion of the casing 3. It comprises a plurality of chuck claws 4 and a hydraulic cylinder 5 mounted on the upper part of the casing 3 for operating the chuck claws 4.

The casing 3 is formed in a cylindrical shape made of a steel pipe or the like having an inner diameter larger than the maximum outer diameter of the existing pile 6, and has a cutting edge 7 attached to a lower end.

As shown in FIG. 4 and FIG.
Is formed of a steel material or the like, and has an arc-shaped cam groove 8 which is formed in an arcuate edge 4a and a straight edge 4b in a tapered, rear-end circular boat shape. The chuck pawl 4 is provided with a shaft 11, which is mounted between the bearings 10 fixed to the outside of the opening 9 near the lower end of the casing 3.
The cam groove 8 is inserted into the casing 3 so as to substantially vertically extend outside the opening 9 of the casing 3 (see FIG. 5).
Attached so as to be able to move back and forth in the vertical direction around the shaft 11 over a projecting posture (see FIG. 6) that projects substantially horizontally from the opening 9 into the casing 3.

As shown in FIGS. 2 and 3, the upper end of the hydraulic cylinder 5 is pivotally connected to a supporting projection 12 protruding from the upper part of the casing 3 and extends and contracts from the lower end of the hydraulic cylinder 5. A lower end of a flexible cylinder rod 13;
Joint 1 pivotally connected to the rear end of the chuck claw 4
4 are connected by a connecting rod 15 (see FIGS. 4 and 5). The lower end of the cylinder rod 13 and the upper end of the connecting rod 15 are connected by a pivot 16 so that the hydraulic cylinder 5 can extend and contract straight in the vertical direction, and a vertical groove 17 in the vertical direction is formed in the casing 3. A pair of guides 18, 18 are fixed, and both ends of the pivot 16 are slidably fitted in the longitudinal grooves 17, 17, so that the cylinder rod 13 is regulated so as to move vertically up and down straight. I have. The connecting rod 15 is vertically movably inserted into a guide 23 fixed to the casing 3. When the cylinder rod 13 of the hydraulic cylinder 5 is contracted, the chuck pawl 4 is pulled upward by the connecting rod 13 and retreats from the opening 9 to the outside of the casing 3 in a substantially vertical posture (see FIG. 5). Is extended, the chuck pawl 4 is pushed down by the connecting rod 13 and projects from the opening 9 into the casing 3 in a substantially horizontal posture (see FIG. 6).

As shown in FIG. 1, the casing 3 is provided with a pipe 19 for jetting a muddy agent such as water or bentonite in a vertical direction. The lower end 3 faces the opening 20 provided between the chuck claws 4 and 4.

Next, a procedure for pulling out the existing pile 6 using the pulling device having the above-described structure will be described. First, by excavating the ground surface G near the upper end of the existing pile 6 buried underground, the upper end of the existing pile 6 is exposed and its position is confirmed.
Incidentally, the existing pile 6 shown in FIG. 1 and FIG.
This is a pedestal pile in which b and the point 6c are not integrated.

Thus, the casing 3 is driven into the existing pile 6 by the driving machine 1 as shown in FIG. The casing 3 is driven to rotate by a driving machine 1 composed of an earth auger, and is driven into the soil while being digged by a digging blade 7. At this time, a muddy agent such as water or bentonite passes through the pipe 19 and is sent to the lower end of the casing 3, and is ejected from the nozzle 19 a at the tip of the pipe 19 to muddy the soil inside and outside the lower end of the casing 3. Thereby, the casing 3 reduces the frictional resistance with the earth and sand, so that the casing 3 can be easily driven. The driving of the casing 3 is performed to such a depth that the lower end of the casing 3 is about 1 m below the lower end of the existing pile 6.

After the driving, the hydraulic cylinder 5 is extended as shown in FIG. 2B, and the chuck pawl 4 is projected through the connecting rod 15 into the casing 3 as shown in FIG. At this time, whether or not the chuck pawl 4 has sufficiently protruded into the casing 3 can be confirmed by directly viewing the extension length of the rod 13 of the hydraulic cylinder 5 on the ground. After the chuck claw 4 is completely protruded, when a lifting force is applied to the casing 3 by the driving machine 1, the lifting force is applied to the existing pile 6 by the chuck claw 4 abutting on the lowermost end of the existing pile 6, and the casing 3 Can be pulled out together with the existing pile 6 and earth and sand in the casing 3.

As described above, the rod 1 of the hydraulic cylinder 5
Since it is possible to confirm whether or not the chuck claw 4 has sufficiently protruded into the casing 3 by directly looking at the extension state of the ground 3 on the ground, it is possible to confirm that the chuck claw 4 is insufficiently protruding in the middle of the existing pile 6. There is no problem of being pulled out, and the whole up to the lowermost point 6c can be reliably pulled out. When the cylinder rod 13 expands to the maximum, this can be detected by a sensor and a lamp, a buzzer, or the like can be operated to make it easier to confirm the expanded state of the cylinder rod 13 more reliably.

After the pull-out, when the hydraulic cylinder 5 is contracted as shown in FIG. 2A, the chuck pawl 4 withdraws out of the casing 3 via the connecting rod 15 as shown in FIG. The existing pile 6 and earth and sand are extracted downward from the casing 3 by its own weight. At this time, the existing pile 6 and the earth and sand in the casing 3 are smoothly extracted in order to reduce friction between the inner peripheral surface of the casing 3 and the mudified earth and sand.

According to the chuck mechanism having the plurality of chuck claws 4 having the above-described structure, the existing pile 6 can be gripped even in the middle. Therefore, it is not necessary to pull out the entire existing pile 6, and if only the upper part of the existing pile 6, for example, only the pillar 6 a of the illustrated existing pile 6 is to be pulled out, the middle of the pillar 6 a is required. It is also possible to grab and pull out. If the length of the existing pile 6 is not known, as shown in FIG. it can.

In order to confirm the upper end of the existing pile 6 before driving the casing 3, it is necessary to excavate deeply when the upper end of the existing pile 6 is deeper than the ground surface. In this case, it is necessary to protect the surface ground because a driving machine cannot be arranged close to the location or affects a building or the like adjacent to the location. For this purpose, a stand pipe 21 having an inner diameter larger than the maximum outer diameter of the casing 3 is driven into the surface layer G as shown in FIG. The earth and sand inside is excavated with a backhoe and discharged. After that, the casing 3 is connected to the stand pipe 2
1 and driven into the ground to surround the existing pile 6
Thereafter, the casing 3 can be pulled out together with the existing pile 6 by performing the same operation as described above.

In the above embodiment, an earth auger is used as the drawing machine 1, but a vibro hammer can be used instead. In this case, the upper end of the casing 3 is detachably connected to the lower end of the vibrohammer.

[0023]

According to the present invention, since the hydraulic cylinder used to operate the chuck pawl into the casing is mounted on the upper part of the casing, the hydraulic cylinder receives the resistance of earth and sand even when the casing is driven. This has the advantage that not only the protection can be achieved without any problem, but also the chuck pawls can be easily confirmed to protrude into the casing, and the existing pile can be completely pulled out.

[Brief description of the drawings]

FIG. 1 is a front view showing a state in which an existing pile pulling device is driven into the ground.

FIG. 2A is a front view showing a hydraulic cylinder attached to a casing of a drawing device in a contracted state, and FIG. 2B is a front view showing the hydraulic cylinder in an extended state.

FIG. 3 is a view taken in the direction of arrow C in FIG.

FIG. 4 is a front view showing a chuck claw attached to a casing of the drawing device in a retracted state.

FIG. 5 is a side view showing a chuck claw attached to a casing of the drawing device in a retracted state.

FIG. 6 is a side view showing a chuck claw attached to a casing of the drawing device in a protruding state.

FIG. 7 is an explanatory diagram showing an example of a driving process of the drawing device.

FIG. 8 is a front view showing a protection state of a surface ground to be constructed before pulling out an existing pile.

[Description of Signs] 1 Driving machine 3 Casing 4 Chuck claw 5 Hydraulic cylinder 6 Existing pile 8 Cam groove 11 Shaft 13 Cylinder rod 15 Connecting rod 19 Piping

Claims (3)

[Claims] 1. A cylindrical casing connected to a driving machine and having an inner diameter larger than the maximum outer diameter of an existing pile, and attached to a lower portion of the casing so as to protrude into the casing by being driven by a hydraulic cylinder. An existing pile pulling device provided with a chuck claw, wherein the hydraulic cylinder is attached to an upper portion of the casing, and a rod end of the hydraulic cylinder and the chuck claw are connected by a connecting rod. Pulling equipment for existing piles. 2. The chuck pawl has an arcuate cam groove, the cam groove being inserted through a shaft fixed to a lower portion of the casing, and the connecting rod being raised by a contraction operation of the hydraulic cylinder. The chuck claws retreat out of the casing in a substantially vertical position, and the connecting rods are lowered by the extension operation of the hydraulic cylinder, so that the chuck claws project into the casing in a substantially horizontal position. Item 2. An existing pile pulling device according to Item 1. 3. A pipe for allowing a muddy agent such as water or bentonite to be jetted into and out of the lower end of the casing in the casing in a vertical direction.
Pulling device for existing piles as described.