JP7295369B1 - Pile gripping claw - Google Patents

Abstract

The object of the present invention is to provide a pile gripping claw that can be applied to an existing pile pulling device and that can contribute to high stabilization of the pulling capacity and improvement of work efficiency in the existing pile pulling operation. A pile gripping claw (10) is arranged at the tip of a casing (3) of an existing pile pulling-out device (Z), the pile gripping claw (10) is connected to the peripheral wall of the casing (3), and the tip (10b) thereof extends from the peripheral wall side. The casing 3 can be swung downward toward the center of the casing 3, and a substantially truncated cone-shaped bit 11 or the bit 11 is provided on the plane portion of the tip portion 10b on the casing center side. A plurality of bit groups 12, 13 and 14 are arranged and fixed in rows at predetermined intervals in the direction. When the existing piles 9 are hooked by the pile gripping claws 10, the bits 11 of the pile gripping claws 10 bite into the existing piles 9 to prevent slippage between the existing piles 9 and the pile gripping claws 10. As a result, the hooking performance with respect to the existing pile 9 is remarkably improved, and the pile extraction work can be performed efficiently and with high reliability. [Selection drawing] Fig. 2

Description

TECHNICAL FIELD The present invention relates to a pile gripping claw applied to an existing pile extraction device for extracting an existing pile buried in the ground without destroying it.

Conventionally, there has been proposed an existing pile extraction device that extracts and removes piles (that is, existing piles) buried in the foundation of the building from the ground without destroying them, for example, when rebuilding a building. One of them is an existing pile extraction device shown in Patent Document 1.

This existing pile extraction device relates to the application of the applicant of the present application, and has an inner diameter larger than the existing pile and is equipped with an excavating edge at the tip of the casing. Pile gripping claws that can penetrate through and protrude inside are provided at two positions facing each other in the radial direction across the center of the casing, or at three positions facing each other radially around the center of the casing, and this pile gripping The pawl is arranged on the upper side of the casing, and is configured to swing from the side of the peripheral wall of the casing to the center side by the driving force of the driving device.

When pulling out the existing pile, the casing is driven into the ground so as to surround the existing pile with a predetermined gap. Then, in the first method, the casing is driven in until the tip thereof is slightly deeper than the tip (lower end) of the existing pile, and in this state, the pile gripping claws are protruded from the casing peripheral wall side toward the center side. In this method, the pile gripping claws are engaged with the tip of the existing pile from below, and the casing is pulled up in this state to pull out the existing pile.

In the second method, the casing is driven into the casing to a depth corresponding to the required position in the middle of the existing pile. In this method, the pile gripping claws are pressed against the peripheral surface of the existing pile from the outer peripheral side to generate a required frictional force between them, and the existing pile is pulled out by pulling up the casing in this state.

Japanese Patent Application No. 2018-235893

However, in the pull-out device shown in Patent Document 1, when the existing pile is pulled out by the first method, the effect of locking the pile gripping claws to the existing pile is high, so there is no particular problem. When the existing pile is pulled out by the second method, the above-mentioned pile gripping claws are brought into contact with the outer peripheral surface of the above-mentioned existing pile under strong pressure, and the pull-out force is ensured by the frictional force acting between them. , For example, when the pull-out resistance of the existing pile (mainly the frictional resistance acting between the outer peripheral surface of the existing pile and the surrounding soil) increases and exceeds the pull-out force, the outer peripheral surface of the existing pile and the pile Slippage will occur between the gripping claws. That is, there is a problem that it is difficult to secure a stable extraction ability because the extraction ability is greatly influenced by the properties of the soil around the pile and the smoothness (that is, the surface condition) of the outer peripheral surface of the existing pile.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pile gripping claw that can be applied to an existing pile pulling device and that can contribute to highly stable pulling performance and improved work efficiency in the existing pile pulling operation.

The present invention employs the following configuration as a specific means for solving such problems.

In the first invention of the present application, at the tip of a cylindrical casing that is driven into the outer peripheral side of the existing pile so as to enclose the existing pile, two positions that face each other in the radial direction across the center of the casing, or the The pile gripping claws are arranged at three positions radially facing each other from the center, and the pile gripping claws have a substantially band plate-like shape, the base end of which is connected to the peripheral wall of the casing, and the tip end of which is connected to the peripheral wall of the casing. It is swingable from the peripheral wall side toward the center side of the casing in a downward swung state and is driven in the swinging direction by a driving means provided on the casing side, while the surface of the tip portion on the casing center side is the surface of the casing center side. A bit having a substantially truncated cone shape, or a group of bits formed by arranging and fixing a plurality of bits in a row at predetermined intervals in the width direction of the tip portion , is arranged on the plane portion in the longitudinal direction of the tip portion. is provided in a plurality of stages .

In a second invention of the present application, in the first invention, at least the peripheral portion of the first stage bit or the first stage bit group of the flat portion of the pile gripping claw has cemented carbide particles. It is characterized by providing a reinforcing part.

A third invention of the present application is characterized in that, in the first or second invention, the tip end surface of the pile gripping claw is a concave curved surface.

(a) First invention of the present application According to the pile gripping claw according to the first invention of the present application, a substantially truncated cone-shaped bit or the bit is placed at the tip of the pile gripping claw in the width direction of the tip A group of bits arranged and fixed in a row at predetermined intervals is provided in a plurality of stages in the longitudinal direction of the tip part . Since the bit or each bit of the bit group bites into the outer peripheral surface of the existing pile to perform a locking action, slippage between the outer peripheral surface of the existing pile and the pile gripping claw is prevented, As a result, a synergistic effect between the frictional force acting between the existing pile and the pile gripping claw and the locking force of the bit of the pile gripping claw imparts a high pull-out force to the existing pile. The pull-out capability of the pile pull-out device for existing piles is greatly improved, and the reliability of the pull-out work is improved.
In addition, since the bit or the bit group is provided in a plurality of stages in the longitudinal direction of the tip portion, the locking action and anti-slip action of the bit are further improved, and the above effects are further ensured. .

(b) Second invention of the present application In the second invention of the present application, in the first invention, at least the first stage bit of the flat portion of the pile gripping claw, or the periphery of the first stage bit group Since the reinforcing portion having the cemented carbide particles is provided in the portion, that is, the portion where the load is most likely to be applied, the reliability of the strength of each bit is improved, and the effect described in (a) above is obtained. becomes even more pronounced.

(c) Third invention of the present application In the third invention of the present application, in the first or second invention, the tip surface of the pile gripping claw is a concave curved surface. Abutment on the outer peripheral surface of the existing pile prevents the bits from biting into the existing pile, which in turn prevents the existing pile from being pulled out using the pile gripping claws. Reliability is ensured.

1 is an overall external view of an existing pile pulling-out device to which pile gripping claws according to the present invention are applied; FIG. 1 is an overall perspective view of a pile gripping claw according to an embodiment of the present invention; FIG. It is a front view of the front-end|tip part of the said pile holding nail|claw. FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3; FIG. 10 is a plan view of the initial state of contact of the pile gripping claws with the outer peripheral surface of the existing pile. FIG. 7 is a view taken along line BB in FIG. 6; FIG. 5 is an explanatory diagram of a storage state of the pile gripping claws when the existing pile pulling-out device is not working. FIG. 10 is an explanatory diagram of the pile extraction work in a state where the tip of the existing pile is supported from below; FIG. 10 is an explanatory diagram of a pile pulling-out operation in a state in which a middle step portion of an existing pile is clamped by pile gripping claws;

Hereinafter, an embodiment in which an existing pile pulling-out device Z is equipped with pile gripping claws according to the present invention will be described.

FIG. 1 shows an existing pile extracting device Z to which the pile gripping claws 10 according to the present invention are attached and which is used for extracting the existing pile 9 . This existing pile extraction device Z is constructed by connecting a casing 3 via a swivel joint 2 to the lower side of an earth auger 1 suspended from a support base such as a leader.

The casing 3 is composed of a tubular body having an inner diameter dimension (for example, about 500 mm to 600 mm) larger than that of the existing pile to be pulled out by a predetermined dimension. , and the upper end of the split pipe body at the upper end is connected to the lower side of the swivel joint 2 .

The casing 3 is driven into the soil along the existing piles 9 while being rotated by the earth auger 1 to cut off the soil surrounding the existing piles 9 . At the lower end of the casing 3, as shown in FIG. 7, a plurality of tip excavating blades 6 attached to the peripheral wall of the lower end and a plurality of outer edges protruding radially outward from the outer periphery of the lower end. A digging edge 7 is provided.

Then, the soil in contact with the outer circumference of the existing pile 9 is cut by the tip excavating blades 6 at a position appropriately spaced from the outer circumference, and edge cutting is performed. Further, the outer portion of the edge cut portion is excavated in an annular shape having a predetermined width by the plurality of outer excavating blades 7 to form an advancing clearance of the claw cover 16 provided on the outer periphery of the lower end of the lower casing 13 .

Furthermore, after driving the casing 3 around the existing piles 9, the existing piles 9 are hooked to the casing 3 side, and the existing piles 9 are pulled up (pulled out) together with the casing 3. , is provided with a hooking mechanism 5 comprising pile gripping claws 10, which is the gist of the present invention described below.

As shown in FIGS. 7 to 9, the locking mechanism 5 is provided with pile gripping claws 10, which are the gist of the present invention and will be described later.

Here, the structure and the like of the pile gripping claw 10 will be described. As shown in FIGS. 2 to 4, the pile gripping claw 10 is integrally formed of a belt-like body having a predetermined thickness and a predetermined width, and a shaft hole 10f extending in the width direction is provided at the base end 10a. . The tip portion 10b is formed into a flat surface, and a plurality of bits 11 made of super-high material and formed in a truncated cone shape are projected upward from the flat surface by a predetermined height. , 4 pieces (these are referred to as the first bit group 12) in the width direction of the pile gripping claw 10 at the position closest to the tip surface, and on the upper side (closer to the base end 10a) at a predetermined interval in the width direction Three bits (this is referred to as the second bit group 13) and four bits (this is referred to as the third bit group 14) are provided at predetermined intervals in the width direction on the upper side thereof.

Further, the tip surface 10e of the pile gripping claw 10 is formed as a concave curved surface recessed toward the base end portion 10a side, and the pile gripping claw 10 swings toward the center of the casing 3 so that the tip surface 10e of the pile gripping claw 10 moves toward the existing pile 9. Excessive interference when approaching the outer peripheral surface 9a of the pile 9 is prevented, and the biting performance of the bits 11 into the outer peripheral surface 9a of the existing pile 9 is ensured.

Further, as shown in FIGS. 2 and 3, the peripheral portion of each bit 11 of the first bit group 12 of the pile gripping claw 10 is provided with a reinforcing portion having cemented carbide particles.

7 to 9 show how the pile gripping claw 10 constructed as described above is assembled into the existing pile pulling-out device Z. FIG. In this embodiment, the pile gripping claws 10 are provided in the claw covers 16 formed on the peripheral wall portion of the casing 3 at two positions facing each other in the radial direction with the center of the casing 3 interposed therebetween. , and the surfaces on which the bits 11 are arranged are oriented toward the center of the casing. It is

Therefore, the pile gripping claws 10 can be vertically moved by transmitting the driving force of the driving part 4 such as the hydraulic cylinder arranged at the upper end of the casing 3 through the transmission material 8 arranged along the casing 3 . At the same time as the pile gripping claw 10 is moved in the direction (UD direction), the cam receiving surface 33 formed on the back side of the pile gripping claw 10 engages with the cam 32 arranged on the lower side of the claw cover 16 in sliding contact. As a result, the pile gripping claws 10 are driven in a direction (FR direction) toward and away from the center of the casing 3 in a downward swung state about the connecting pin 31 .

The state shown in FIG. 7 is a state in which the casing 3 is driven into the outer peripheral side of the existing pile 9. In this state, the pair of left and right pile gripping claws 10 are both on the claw cover 16 side. , the amount of protrusion of the casing 3 toward the inner circumference is minimized, and the casing 3 can be driven well.

In the state shown in FIG. 8, the casing 3 is driven into the existing pile 9 below the tip portion 9b, the existing pile 9 is supported from below the lower end portion in an embraced state, and the casing 3 is pulled up. Together with , the existing pile 9 is pulled out. In this case, the pile gripping claws 10 are swung largely toward the center of the casing, and the bits 11 provided on the pile gripping claws 10 bite into the lower end portions 9b of the existing piles 9 to prevent the gap between them. The pile gripping claws 10 are hooked to the lower end portions 9b of the existing piles 9 while the slippage of the piles 9 is suppressed.

At this time, among the bits 11 of the pile gripping claws 10, among the bits 11 of the third bit group 14, the two bits 11 positioned inside in the line-up direction first move toward the tip portion 9b of the existing pile 9. Therefore, the contact surface pressure at the tip of the bit 11 is greater than when the bits 11 of other bit groups are also in contact at the same time, and the bit 11 easily and reliably attaches to the existing pile without causing slippage. It bites into the lower end portion 9b of 9. As a result, the hooking performance of the hooking mechanism 5 on the existing pile 9 is significantly improved, and the work of pulling out the existing pile 9 is performed efficiently and with high reliability.

In the state shown in FIG. 9, the casing 3 is driven into the middle position of the existing pile 9, the middle part of the upper existing pile 9 is locked by the pile gripping claws 10 of the locking mechanism 5, and pulled out. state. In this state, since the swinging angle of each of the pile gripping claws 10 is small, the existing piles 9 are particularly prone to slip.

However, in this embodiment, when the bits 11 of the pile gripping claws 10 come into contact with the outer peripheral surface 9a of the existing pile 9, the bits 11 of the respective bit groups do not come into contact at the same time. Since the two bits 11 at the center of the bit group 12 are brought into contact first, the contact surface pressure of the bits 11 is greater than when the other bits 11 are also brought into contact at the same time. It easily and surely bites into the outer peripheral surface 9a of the existing pile 9 without causing slippage. As a result, the hooking performance for the existing pile 9 by the hooking mechanism 5 is remarkably improved, and the existing pile can be pulled out even though the outer peripheral surface 9a of the existing pile 9 is hooked. 9 is performed efficiently and with high reliability.

INDUSTRIAL APPLICABILITY The pile gripping claw according to the present invention can be widely used in an existing pile extraction device.

REFERENCE SIGNS LIST 1 Earth auger 2 Swivel joint 3 Casing 4 Drive unit 5 Locking mechanism 6 Tip excavation claw 7 Outer excavation claw 8 Transmission material 9 Existing pile 10 Pile gripping claw 11 Bit 12 First bit group 13 Second bit group 14 Third bit group 15 Reinforcing portion 16 Claw cover 31 Connecting pin 32 Cam 33 Cam receiving surface Z ・・・Existing pile extraction device

Claims (3)

At the tip of a cylindrical casing that is driven into the outer peripheral side of the existing pile so as to enclose the existing pile, two positions that face each other in the radial direction across the center of the casing, or three positions that face each other radially from the center pile gripping claws respectively arranged in
The pile gripping claw has a substantially band plate-like shape, the base end of which is connected to the peripheral wall of the casing, and the tip end of which swings downward from the peripheral wall toward the center of the casing. and driven in the swinging direction by drive means provided on the casing side,
The surface of the tip portion facing the center of the casing is a flat portion, and on the flat portion, a substantially truncated cone-shaped bit or a plurality of such bits are arranged and fixed at predetermined intervals in the width direction of the tip portion. A pile gripping claw , wherein a group of bits are provided in a plurality of stages in the longitudinal direction of the tip portion . In claim 1 ,
A pile gripping claw characterized in that a reinforcing portion containing cemented carbide particles is provided on at least the peripheral portion of the first stage bit or the first stage bit group of the flat portion of the pile gripping claw. . In claim 1 or 2 ,
The pile gripping claw is characterized in that the tip end surface of the pile gripping claw is formed into a concave curved surface.

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