JP3845604B2 - Plug for holding pile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pile gripping plug that can be suitably used when a pipe pile is gripped by a pile driving machine such as a soilless rotary pile driving machine.
[0002]
[Prior art]
As one method for driving a pile into the ground, one using a non-exhaust type rotary pile driver is known (see Japanese Patent No. 2632443).
In many cases, the pile used in this method is a pipe pile (centrifugal cast pipe) obtained by centrifugal casting using steel or iron as a raw material. Such a pipe pile has a tip surface formed substantially orthogonal to the axis, and a spiral wing is fixed to the outer peripheral surface near the tip.
[0003]
The above-described soilless rotary piling machine is configured based on, for example, a crane truck, and a tower for standing on the ground is suspended from the boom tip of the crane truck. The motor is held so as to be movable up and down.
This motor is suspended through a hook that can be raised and lowered by a crane. A catcher for gripping the pipe pile is provided at the lower part of the motor.
That is, with the catcher holding the pile head (upper end) of the pipe pile, pull up the motor until the pipe pile is in an upright state, and lower the motor while rotating the pipe pile with the motor from this state, The pipe pile is pressed into the ground with screwing action.
[0004]
By the way, the catcher is provided with a plurality of rollers arranged in a uniform manner in a circumferential arrangement, and a cam mechanism that moves all of these rollers all at once in the spherical center direction. To grasp the outer peripheral surface of the pipe pile (see Japanese Patent Publication No. 4-60911).
In this type of catcher, in order to prevent the outer surface of the pipe pile from being damaged by the pressure of each roller, an arc plate liner is interposed between the roller and the outer surface of the pipe pile. Therefore, a proposal has been made to press the outer peripheral surface of the pipe pile in a surface contact manner (see Japanese Patent Publication No. 4-49194).
[0005]
[Problems to be solved by the invention]
As described above, the pipe pile has a hollow cylindrical shape made of a centrifugal cast pipe. Therefore, the outer diameter has a certain degree of dimensional variation, and the roundness of the outer diameter may include a shape that has been deformed to some extent (an oval shape or a shape having irregularities in the circumferential direction).
Therefore, when a pipe pile with a low cross-sectional shape is gripped by the catcher in this way, the pressure balance by each roller or liner is lost, causing the pipe pile to be deformed into an increasingly distorted shape. There was a case.
[0006]
If the pipe pile is deformed by gripping with the catcher in this way, the pipe pile cannot be securely fixed and may cause idle rotation when being pressed into the ground, and then the pipe pile cannot be removed from the catcher. There is a fear.
The present invention was made in view of the above circumstances, and when gripping a pipe pile by a catcher or the like of a soilless rotary pile driver, the pipe pile can be reliably gripped without being deformed, It is another object of the present invention to provide a plug for holding a pile that allows the pipe pile to be attached to and detached from the catcher easily and quickly.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has taken the following measures.
That is, the pile gripping plug according to the present invention is configured so that when the upper end outer surface of the pipe pile is gripped by a pile gripping catcher provided in a pile driving machine such as a non-exhaust type rotary pile driving machine, A pile gripping plug to be inserted into the upper end portion, which is held in a screw shaft, a nut member screwed to the screw shaft and held so as to be movable, and an arrangement surrounding the screw shaft. A plurality of expanding / contracting pieces in the circumferential direction and a tightening ring wound around the plurality of expanding / contracting pieces and biasing all the expanding / contracting pieces in the diameter reducing direction, and the nut member is screwed together A truncated cone or a truncated pyramid having the axis of the shaft as an axis, and the plurality of expansion / contraction pieces have a space portion having the same shape as the nut member in an arrangement surrounding the screwing shaft; By moving the shaft between the outer periphery of all the expansion / contraction pieces The outer diameter is formed so that it can be expanded and contracted, and the diameter is made smaller than the inner diameter of the pipe pile before being inserted into the upper end of the pipe pile, and the diameter is expanded after being inserted into the upper end of the pipe pile. The gripping force of the catcher is supported from the inside by coming into contact with the inner peripheral surface of the pile at a plurality of locations in the circumferential direction.
[0008]
When such a plug is used, even if the outer peripheral surface of the pipe pile is gripped by the catcher, the pipe pile is prevented from being deformed by the gripping force.
Therefore, the pipe pile can be securely fixed, and no idling occurs when it is press-fitted into the ground. Moreover, the pipe pile cannot be removed from the catcher.
When pre-Symbol nut member has a truncated pyramidal shape, the number of said plurality of scaling pieces is preferably equal to the sides of the bottom surface of the truncated pyramid.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
3 and 4 show an embodiment of a pile gripping plug 1 according to the present invention. FIG. 1, FIG. 2R> 2, FIG. 5 and FIG. Yes.
As shown in FIG. 5 and FIG. 6, the plug-free plug 1 will be described from the tip of the boom 3 of the pile driver 2. The motor 6 suspended via the wire 4 and the hook 5 is incorporated in a lower part thereof with a catcher 8 for gripping the pipe pile 7.
[0010]
Therefore, the plug 1 moves up and down together with the motor 6 when the pile driving machine 2 feeds or winds up the wire 4 and moves the motor 6 up and down along the tower 10.
The catcher 8 will be briefly described. As shown in FIGS. 1 and 2, the catcher 8 includes a plurality of rollers provided in a circumferential arrangement so as to surround the upper end portion of the pipe pile 7. 12 and a cam mechanism 13 that moves all the rollers 12 all at once in the direction of the sphere.
[0011]
The cam mechanism 13 has a cam ring 14 that surrounds the arrangement of all the rollers 12, and an arc-shaped concave cam 15 corresponding to each roller 12 is formed on the inner peripheral surface of the cam ring 14. It has become a thing.
Each roller 12 is held in a predetermined arrangement by a ring-type roller bracket 16 and is individually rotatable in a state in which the roller 12 is prevented from shaking by a ring spring 17.
Accordingly, by rotating either one of the cam ring 14 or the roller bracket 16 relative to each other, all the rollers 12 move all at once in the direction of the sphere and grip the pipe pile 7 or move in the opposite direction to move the pipe pile 7. Will be released.
[0012]
And with respect to such catcher 8, the plug 1 for pile holding | grip which concerns on this invention is integrated integrally with respect to the arrangement center (center of the roller bracket 16) of all the rollers 12, or this catcher 8 Used as a separate body.
As shown in FIGS. 3 and 4, the plug 1 has a collet structure.
That is, the plug 1 includes a screwing shaft 20, a nut member 21 that is movably held by being screwed to the screwing shaft 20, and a plurality of circumferential members that are held in an arrangement surrounding the screwing shaft 20. And the expansion / contraction piece 22. A tightening ring 23 is wound around the plurality of expansion / contraction pieces 22 to urge all the expansion / contraction pieces 22 in the diameter reducing direction.
[0013]
The screw shaft 20 is formed as a disc-shaped base 27 having a through-hole 25 at the center, with bolts 26 skewered into the through-hole 25. Whether the base 27 and the bolt 26 are rotatable with respect to each other or fixed so as not to rotate is not limited. In addition, the base 27 is not essential in the first place.
On the other hand, the nut member 21 is formed as having a female screw portion 28 that can be screwed onto the bolt 26 of the screw shaft 20. The nut member 21 is formed to be long in the axial direction and have a tapered shape.
[0014]
When the nut member 21 is screwed onto the screw shaft 20, the small diameter side in the taper shape is directed to the base 27, and the large diameter side is directed to the bolt tip.
As shown in FIG. 2, in the present embodiment, six expansion / contraction pieces 22 are provided in total. However, the number of the expansion / contraction pieces 22 is not particularly limited.
Each expansion / contraction piece 22 has a cross-sectional fan shape, has a predetermined length in the axial direction thereof, and forms a cylindrical body by combining all the expansion / contraction pieces 22. Further, the thickness of each expansion / contraction piece 22 (corresponding to the radial direction dimension of the cylindrical body) is gradually increased in the axial direction so that the hole formed in the center portion when such a cylindrical body is formed becomes a tapered hole. It is formed to change.
[0015]
The tapered hole at this time is adapted to the tapered shape which is the outer shape of the nut member 21 described above. However, the taper angles of both need not be exactly the same, and may be approximated. In particular, the nut member 21 may be a sphere, a hemisphere with a spherical surface directed toward the base 27 of the screw shaft 20, or may be formed as a polygonal solid such as a triangular frustum. Good.
Each expansion / contraction piece 22 is provided with a ring groove 30 for fitting the tightening ring 23 on the outer peripheral surface side when the cylindrical body is formed. In the present embodiment, two ring grooves 30 are provided at predetermined intervals in the axial direction.
[0016]
Between each of the expansion / contraction pieces 22 and the nut member 21 described above, there is provided a detent means 32 for holding the two in a non-rotatable manner.
The anti-rotation means 32 is a spline-like structure composed of a combination of a groove 33 whose longitudinal direction is directed in the axial direction and a ridge 34 engaged therewith.
In the present embodiment, the protrusion 34 is provided on the nut member 21 side and the groove 33 is provided on the expansion / contraction piece 22 side. However, the groove 33 and the protrusion 34 can be provided in a relatively reverse manner. is there. Further, the combination pitch of the grooves 33 and the protrusions 34 can be made fine and serrated.
[0017]
The fastening ring 23 is a ring formed by making an elastic material such as rubber, resin, or coil spring endless. Further, a metal material such as a spring material may be bent into a ring shape and divided at one place on the circumference. In any case, the cross-sectional shape is not limited at all.
In the plug 1 having such a collet structure, the nut member 21 is axially moved along the screwing shaft 20 by changing the screwing degree of the nut member 21 with respect to the screwing shaft 20.
[0018]
Therefore, when the nut member 21 is axially moved in the direction of approaching the base 27 of the screwing shaft 20, the nut member 21 is inserted into the space between the screwing shaft 20 and the expansion / contraction piece 22. Therefore, the entire expansion / contraction piece 22 is pushed outward in the radial direction while being restricted by the winding state by the tightening ring 23. Therefore, the outer diameter of the plug 1 as a whole is enlarged.
On the other hand, when the nut member 21 is moved in the direction of approaching the bolt tip of the screwing shaft 20, the nut member 21 is extracted from the circumference of the screwing shaft 20 and the expansion / contraction piece 22. Therefore, the entire expansion / contraction piece 22 receives the tightening force from the tightening ring 23 and is squeezed radially inward. Therefore, the outer diameter of the plug 1 as a whole is reduced.
[0019]
For this reason, the diameter of the plug 1 is reduced, the base 27 of the screw shaft 20 is left outside from the upper end of the pipe pile 7, and then the plug 1 is moved to the upper end of the pipe pile 7. Inserting and rotating the screwing shaft 20 in this inserted state, the nut member 21 is brought close to the base 27.
Thereby, as described above, the plug 1 expands through the radially outward push-open state by the full expansion / contraction 22, so that the plug 1 presses the inner peripheral surface of the upper end portion of the pipe pile 7 from the inside to the outside. Is obtained.
[0020]
Therefore, even if the upper end portion of the pipe pile 7 in this state is gripped by the catcher 8 of the soilless rotary pile driver 2 as shown in FIG. 1 and FIG. As a result, the pipe pile 7 can be securely fixed, and no idle rotation occurs when it is press-fitted into the ground. Of course, the pipe pile 7 cannot be removed from the catcher 8.
7 and 8 show another embodiment of the plug 1, and in order to reduce the weight of the expansion / contraction piece 22, a hole 35 penetrating vertically is provided. In addition, the tightening ring 23 accommodated in the ring groove 30 is two in order to be safe even if one is broken.
[0021]
FIG. 9 shows another embodiment of the plug 1.
That is, the nut member 21 is not formed in a circular tapered cylindrical shape on the outer peripheral surface, but is formed in a regular hexagonal tapered truncated pyramid.
The polygonal shape of the nut member 21 is the same as the number of divisions of the expansion / contraction pieces 22. Therefore, if the number of divisions of the expansion / contraction pieces 22 changes, the number of sides of the polygon also changes. In this way, the contact accuracy (uniform contact) is improved by making the tapered contact a flat surface instead of a curved surface.
[0022]
By the way, this invention is not limited to the said embodiment, It can change suitably according to embodiment.
The pipe pile 7 may be a type in which only one of them is driven or a type in which a plurality of pipe piles are driven deeply while connecting a plurality of pipe piles. Thus, when connecting the pipe pile 7, the advantage that a connection failure can be prevented is also acquired with the said effect that the pipe pile 7 does not deform | transform.
The configuration of the soil-free rotary piling machine 2 and the catcher 8 is not limited at all. In particular, the pile driving machine is not limited to the soil-free rotary pile driving machine 2.
[0023]
【The invention's effect】
As is apparent from the above description, the plug for holding a pile according to the present invention is inserted into the upper end of the pipe pile so that the pipe pile is held by a catcher or the like of a soilless rotary pile driver. In this case, the gripping force can be backed up and the pipe pile is prevented from being deformed by the gripping force.
Further, in the pile driving method according to the present invention using this plug, since the pipe pile can be reliably fixed, the press-fitting into the ground is ensured, and the pipe pile can be easily and quickly attached to and detached from the catcher.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view taken along line BB in FIG. 6 and shows a use state of a pile gripping plug according to the present invention.
FIG. 2 is a cross-sectional view taken along the line CC of FIG.
FIG. 3 is a side sectional view of a pile gripping plug according to the present invention.
4 is an exploded perspective view (with some members omitted) of the plug shown in FIG. 3; FIG.
FIG. 5 is a side view showing a situation in which a pipe pile is driven into the ground by an earthless rotary pile driver.
6 is an enlarged view taken along line AA in FIG.
FIG. 7 is a side sectional view showing another embodiment of the plug.
FIG. 8 is a bottom view of FIG. 7;
FIG. 9 is a bottom view showing another embodiment of the plug.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plug 2 Undrained rotary pile driver 7 Pipe pile 8 Catcher 20 Screwing shaft 21 Nut member 22 Expansion / contraction piece 23 Tightening ring

Claims (2)

When the upper end outer surface of the pipe pile (7) is held by the pile holding catcher (8) provided in the pile driving machine (2), the pile holding plug is inserted into the upper end portion of the pipe pile (7). There,
A screw shaft (20);
A nut member (21) that is screwed onto the screw shaft (20) and is held so as to be axially movable;
A plurality of expansion / contraction pieces (22) in the circumferential direction held in an arrangement surrounding the screwing shaft (20);
A tightening ring (23) wound around the plurality of expansion / contraction pieces (22) and biasing all the expansion / contraction pieces (22) in the diameter reducing direction;
The nut member (21) has a shape of a truncated cone or a truncated pyramid having the axis of the screwing shaft (20) to be screwed as an axis,
The plurality of expansion / contraction pieces (22) have a space portion having the same shape as the nut member (21) in an arrangement surrounding the screwing shaft (20),
The outer diameter formed by the outer surfaces of all the expanding / contracting pieces (22) can be expanded / contracted by moving the nut member (21) axially and moving it between the screw shaft (20) and the expanding / contracting piece (22). Configured,
Before being inserted into the upper end of the pipe pile (7), the inner diameter of the pipe pile (7) is reduced in diameter from the inner diameter of the pipe pile (7) and then expanded into the upper end of the pipe pile (7). A pile gripping plug that contacts the surface at a plurality of locations in the circumferential direction and supports the gripping force of the catcher (8) from the inside. The nut member (21) has a truncated pyramid shape,
The pile gripping plug according to claim 1 , wherein the number of the plurality of expansion / contraction pieces (22) is the same as the number of sides of the bottom surface of the truncated pyramid.

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