JPH10311028A - Joint for joining steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To join screw joints of steel pipe piles at the site in a quick, labor- saving, easy and strong manner. SOLUTION: A bottom metal piece 20 having a male threaded part 24 and a top metal piece 30 having a female threaded part 33 are furnished at the ends of steel pipe piles 100 and 110. The threads 24 and 33 are of multi-start parallel thread type more than three, and the male threaded part 24 is furnished at the tip with a cylindrical part 25 to be loosely fitted in the female threaded part 33, and automatic alignment of the upper and lower screw shafts and driving in can be conducted quickly and certainly owing to the guide function of the cylindrical part 25 and multi-point contacting of the mutual engaging parts of the multiple threads.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique related to steel pipe piles in the field of civil engineering and construction, and is applied to, for example, joining of steel pipe piles used for landslide prevention and support piles, and is used for joining steel pipe piles. Method and joint of steel pipe pile.

[0002]

2. Description of the Related Art Steel pipe piles for preventing landslides are constructed by drilling holes in mountains, slopes, and slopes of the stratum where landslides may occur, and inserting steel pipe piles into the boreholes.
The hole is filled with mortar or the like for stabilization, and a ground surface portion that causes a landslide is sewn and connected to a deep portion of the stratum. Such steel pipe piles have a diameter of, for example, about 200 to 600 mm and a length of several tens of meters depending on the conditions of the construction site. Therefore, it is necessary to connect a plurality of steel pipe piles at the construction site.

On the other hand, there are cases where it is necessary to construct a long support pile under narrow construction conditions such as in an urban area. In such a case, for example, there may be a case where an overhead structure such as an overhead line or a bridge is already present, or a case where a large number of short steel pipe piles need to be connected and laid down in the ground under a roof or the like.
Conventionally, joints for steel pipe piles generally include butt welded joints, welded joints using sleeves, screw joints, flange joints, and the like.

[0004] Welded joints require a long time for welding work, and it is becoming difficult to secure skilled welding workers, and there is a problem that X-ray inspection and the like are required. As an alternative joint, for example, Japanese Patent Publication No. 7-13368 discloses that
The prior art used for the on-site joining operation of a tapered threaded joint is disclosed. Perform joint joining while confirming it visually by the on-site workers. In addition, there is one in which a simple jig obtained by bending a round bar for centering the pile is hung on the head of the lower pile, and the upper pile is guided into the lower pile.

In such a tapered screw, it is not easy to align the upper pile with the lower pile, and it is necessary to set the upper and lower piles with high precision and cautiousness. Special care is required to prevent damage, and if the screws do not engage, the construction will be poor, and the work on site is difficult and inefficient. Flange joints have a problem that the outer diameter increases, and it is conceivable to reduce the outer diameter of the pile end so that the outer diameter does not increase.However, it is not easy to insert bolts or use a wrench, and it takes a long time to construct. It costs.

Japanese Patent Application Laid-Open Nos. 9-3875 and 9-132913 disclose a threaded joint for a pile, in which a guide cylinder is provided on the female screw side, and a guide cylinder which enters the guide cylinder on the male screw side. The guide cylinder and the guide cylinder are fitted to each other to make the pile axes coincide with each other to achieve a normal screw engagement. This technique requires a guide cylinder deeper than the screw length and a guide cylinder longer than the screw length.

[0007]

When the upper and lower steel pipe piles are jointed on site using a screw joint, if the construction vertical accuracy of the lower piles is poor, the screws of the upper and lower piles do not mesh well even if a jig is used. The screw part is burned and damaged, resulting in poor construction.
In addition, a long time is required for the construction. If the screws are not completely engaged, the predetermined strength cannot be obtained, resulting in poor quality, and it is very difficult to take corrective measures.

In the technique using a tapered thread to make the axes of the threaded joints coincide with each other, if the tapered thread is inclined at the mutual thread axis at the beginning of the engagement of the male thread and the female thread, a cross thread (difference in thread) is obtained. When the screw is tightened while being tilted, thread crushing occurs and the performance of the joint is deteriorated. The present invention solves the above-mentioned problems, and in the on-site construction, the joint can be easily aligned in a short time,
An object of the present invention is to develop and provide a joint for steel pipe piles that can be securely and firmly joined.

Another object of the present invention is to construct a long pile by connecting a plurality of short piles having a length of about 2 m, for example, under restricted construction conditions in an urban area or the like. Without damaging the thread when lifting the pile,
An object of the present invention is to provide a joint in which the centering of the upper and lower piles is easy, the screwing is easy, the joining and the like are easy to perform, accurate pile driving is possible, and the joint portion does not come off even when the pile is reversed.

[0010]

The present invention is characterized by taking the following technical means in order to solve the above problems. The structure of the steel pipe pile joint according to the present invention is as follows. That is, each of the steel pipe pile ends is provided with a male cylinder having a male thread and a female cylinder having a female thread, and the thread is a multi-threaded screw having three or more parallel threads. A joint joint for steel pipe piles, characterized in that a cylindrical portion having an outer diameter that fits loosely into the inner diameter of the female screw is provided. The joint according to the present invention is provided with a male-female screw connection cylinder at the end of a steel pipe pile, and employs a multi-start thread to facilitate centering of the steel pipe pile and speed up the connection. Further, a cylindrical portion which is loosely fitted to the inner diameter of the female screw is provided on the distal end side of the male screw of the male cylinder so as to automatically align the center. The outer diameter of the cylindrical portion is a size that is loosely fitted to the inner diameter of the female screw, and has an outer diameter from which the external thread is removed. Since the external thread is a multi-thread thread, the starting end of the external thread is present in the plane perpendicular to the screw axis by the number of the multi-thread thread, and the female thread side is also in the same cross section perpendicular to the screw axis. Since there is a thread with the same phase as many as the number of threads, engagement of the screws starts at many positions, and the cylindrical part fits into the inner diameter of the internal thread and the position is determined. Normal alignment of the screws is easily achieved while the axes are easily aligned.

In this joint structure, the axial length of the cylindrical portion does not matter. When connecting the upper and lower piles, this cylindrical part serves as a guide, and it is sufficient if there is a minimum dimension sufficient to match the axis of the upper and lower piles, there is no need for a dimension longer than the screw length at all, it is a short dimension , Centering becomes easy. Such piles are used, for example, in the case of connecting a large number of short piles each having a length of about 2 m under a structure to construct a long pile of several tens of meters. It is preferably used.
In such a case, there is a case where it is desired to save labor for attaching and detaching the alignment jig and the like, and in such a case, the effect is particularly exhibited.

In the present invention, instead of the cylindrical portion,
An inner cylindrical portion which is loosely fitted to the outer diameter of the male screw may be provided at the tip of the female side cylindrical body, and the effect of facilitating centering is equivalent to that of the cylindrical portion. Further, in addition to the cylindrical portion, if an inner cylindrical portion that is loosely fitted to the outer diameter of the male screw is provided at the tip of the female-side cylindrical body, the alignment is further facilitated. In the steel pipe pile according to the present invention, when the upper pile is lifted up and the lower end thereof is brought into contact with the lower pile, the axes are automatically aligned, and the trouble of centering is not required.

Further, when an inner peripheral seat with which the distal end of the cylindrical portion comes into contact is provided on the inner surface of the female side cylinder, it serves as a stopper for stopping screwing, contributes to tightening of the screw, and has a large axial dimension. A thrust transmission function can be provided.
Further, an outer peripheral seat is provided on the outer surface of the male-side cylindrical body at which the tip of the inner cylindrical portion abuts directly or via a waterproof rubber ring, and the stopper, the tightening of the screw, the action of transmitting thrust, or It is preferable to provide a watertight sealing property.

[0014] Such piles may need to be reversed during construction. Therefore, a set bolt for preventing the screw joint from being loosened when the screw is reversed is provided. In a long pile formed by connecting a large number of short piles, since there are many joints, it is necessary to pay particular attention to the loosening of screws. The set bolt has a set bolt mounting hole in the cylindrical wall of the female side cylinder,
On the outer circumference of the cylindrical portion of the male side cylinder, a concave hole into which the tip of the set bolt is fitted, or a circumferential headband-shaped concave groove, or a long-hole-shaped concave hole or concave groove along the cylindrical generatrix is provided. . From the viewpoint of sealing the inside and outside of the steel pipe pile, it is better that the concave hole is not a through hole. However, when it is not necessary to seal the inside and outside of the steel pipe pile, a through hole may be used instead of the concave hole.

With this set bolt, the connection between the upper and lower piles can be ensured, and the function of transmitting rotational torque and transmitting thrust between the upper and lower piles can be easily provided. It is preferable that a pair of mounting holes for the set bolts are provided symmetrically with respect to the center point of the cylindrical body, and the concave holes are arranged at equal intervals on the circumference at least N pairs with respect to the center point of the cylindrical body. However, N is the number of threads of the multi-thread screw. For example, the number of concave holes is 6 or more even number in the case of 3 thread screws, 8 or more even number holes in the case of 4 thread screws, and 10 or more even number holes in the case of 5 thread screws.
By doing so, the male screw and the female screw are sufficiently screwed in, and then the screw is returned in the axial direction by a stroke equal to or less than half of the screw pitch, so that the positions of the recessed hole and the set bolt can be matched. It is easy to increase the dimensional accuracy of the fitting between the bolt and the concave hole and the accuracy of the mutual arrangement position, and to secure the processing accuracy.

Also, an eyebolt can be attached to the mounting portion of the set bolt and used as a suspender when handling a steel pipe pile. This eliminates the risk of damaging the thread when hanging a steel pipe pile having a thread for a joint. Furthermore, commonality is provided so that it can be used as a mounting bolt hole when attaching a yatco (an auxiliary tool temporarily installed on the pile head for hiring piles, pile driving, etc.) to the head of the steel pipe pile. By designing, it can be used for multiple purposes.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. FIG. 1 (a) shows a lower end metal fitting 20 which is a male cylinder attached to a lower end of a steel pipe pile of the present invention, and FIG. 1 (b) shows an upper end of the steel pipe pile. In the upper metal fitting 30 which is a female side cylindrical body to be attached, a left half is an external side view and a right half is a longitudinal sectional view. The lower metal fitting 20 is formed by vertically integrating an upper cylinder 21 and a lower cylinder 23. The upper cylinder 21 has an outer diameter equal to the outer diameter of the steel pipe pile 100, and is provided at its upper end with a groove 22 for welding 101 to the steel pipe pile 100. The lower cylinder 23 is formed with a male screw 24 that is screwed into the female screw 33 of the upper end hardware 30 of the lower pile 110. A cylindrical portion 25 having an outer diameter equal to the bottom diameter of the male screw 24 is formed at the tip of the male screw 24. Upper steel pipe pile 10
0 and the lower steel pipe pile 110,
Reference numeral 5 loosely fits into the inner diameter of the female screw 33 and guides the upper pile so that the axes of the upper and lower piles are automatically matched.

The lower end surface 26 of the cylindrical portion 25 is perpendicular to the axis of the steel pipe pile. Further, at the rear end of the male screw 24, an outer peripheral seat 27 formed of a surface perpendicular to the axis of the steel pipe pile is provided. In addition, an appropriate hole or notch 28 is provided on the outer diameter surface of the lower end metal part 20, and a steel pipe pile 1 such as a bar, a spanner, a tong, or the like is provided.
It is preferable that a tool or a jig for facilitating turning of 00 is engageable.

The metal fitting 30 at the upper end of the steel pipe pile 110 has the same outer diameter as that of the steel pipe pile 110, and has a circumferential groove 32 at the lower end for welding 111 to the steel pipe pile 110. On the upper part of the upper end hardware 30, the male screw 2 of the lower end hardware 20 is provided.
4 is provided, and the female screw 33 is screwed with the female screw 33.
An inner surface seat 34 having a plane perpendicular to the axis is formed at the lower end of the shaft. An inner cylinder 38 is formed above the female screw 33. The inner diameter of the inner cylindrical portion 38 matches the diameter of the thread bottom of the female screw 33, and is loosely fitted to the outer diameter of the male screw 24. When joining the upper steel pipe pile 100 and the lower steel pipe pile 110, the inner cylindrical portion 38 is loosely fitted to the outer diameter of the male screw 24, and the upper pile is automatically adjusted so that the axes of the upper and lower piles are automatically matched. To guide.

An upper surface of the upper metal part 30 is provided with an axis perpendicular surface 35, and a chamfered portion 36 is provided on an inner peripheral portion thereof. In this embodiment, the distance between the inner surface seat 34 and the upper end surface 35 is slightly smaller than the distance between the lower end surface 26 of the lower end hardware 20 and the outer peripheral seat 27, and the chamfered portion 36 is provided with a seal rubber packing. A seal seat is formed to enhance the sealing performance. However, the distance between the inner surface seat 34 and the upper end surface 35 is formed larger than the distance between the lower end surface 26 of the lower end hardware 20 and the outer peripheral seat 27, and the upper end surface 35 of the upper end hardware 30 is formed.
And the outer peripheral seat 27 of the lower metal fitting 20 may be in close contact with each other, and a dimensional relationship may be formed such that a gap is formed between the lower end surface 26 of the lower metal fitting 20 and the inner seat 34 of the upper metal fitting 30.

In the embodiment shown in FIG. 1, the cylindrical portion 25 and the inner cylindrical portion 38 are both provided. However, even if only one of them is omitted and the other is omitted, the above guide for centering is provided. Function is enough. It is easier and more reliable to have both. The male screw 24 and the female screw 33 are formed as parallel threads having no taper, and are three or more threads. Parallel screws can be joined with lower torque than taper screws. In the case of a multi-thread screw, the lead in the axial direction during one rotation is multi-thread times the screw pitch.
Therefore, quick screwing can be performed.

By providing a cylindrical portion 25 having a screw bottom diameter at the lower end of the upper pile (the lower end of the lower end hardware 20), the male screw 24 is formed.
In the initial stage of starting screwing into the female screw 33, the cylindrical portion 25 serves as a guide to facilitate the engagement of the screw, and the screwing becomes easy. By screwing in, the lower end surface of the upper pile (the lower end surface 26 of the lower end hardware 20) and the inner peripheral seat 3 of the lower pile
4 and 4 makes it possible to significantly increase the strength and bending rigidity of the joint portion of the pile.

This joint has a male screw 24 and a female screw 3
The intrusion of groundwater or the like into the threaded portion with the seal 3 can be prevented by sealing with the waterproof rubber ring 37, so that there is no risk of deterioration of the screw and a decrease in the bonding strength of the steel pipe pile. FIG. 2 is a view taken in the direction of arrows AA in FIG.
A female screw 33 having four threads is provided inside the upper end face 35 of the zero. FIG. 3 is a plan view of a conventional single thread shown for comparison with FIG. 4 of the embodiment of the present invention shown in FIG.
In the threaded screw, there are four starting portions 39 (portions surrounded by phantom lines) of the screw in the same plane perpendicular to the screw axis. On the other hand, the same applies to the male screw that meshes with the female screw, so that at the beginning of the meshing of the male screw with the female screw, the tip of the screw contacts at four points in a plane perpendicular to the screw axis. Therefore, a stable and smooth start of meshing is always ensured, and poor meshing does not occur at all. The joining joint of the present invention has a centering guide function by the cylindrical portion 25 and the inner cylindrical portion 38,
The synergistic effect with the fact that the meshing start ends are present at multiple points in the same plane ensures quick and smooth joining at the site. In FIG. 3 having a conventional single thread, there is only one starting end 39 of the screw, so if the axes of the male screw and the female screw are inclined, the start of meshing is not smooth, and the stable state as in the present invention is obtained. The start of engagement cannot be ensured, and there is a possibility that cross threads will occur.

FIGS. 4 to 6 are explanatory views schematically showing the joining process of the joining joint of the embodiment. FIG. 4 shows the lower metal fitting 20.
1 shows a state immediately before the male screw 24 and the female screw 33 of the upper end metal part 30 start to engage with each other. Lower end hardware 20
The inner cylindrical portion 38 at the upper end of the upper metal fitting 30 fits into the outer diameter of the male screw 24, and the axis of the male screw 24 and the axis of the female screw 33 are substantially the same. Coaxial centering automatically. At the same time, the engagement start end of the male screw 24 and the female screw 33 is, as described in FIG.
They are in contact with each other at four points in a plane perpendicular to the axis. When the lower metal fitting 20 is twisted, the screws are smoothly engaged immediately.

FIG. 5 shows a state in which the screw is being smoothly and rapidly screwed. FIG. 6 shows that the screwing is completed, and the lower end surface 26 of the lower end hardware 20 is moved to the inner surface seat 34 in the upper end hardware 30.
Shows a state in which it is in contact with. FIG. 7 is a partial vertical sectional view of the steel pipe piles 100 and 110, showing a state in which the joint of the embodiment using the waterproof rubber ring has been completely joined. The lower end surface 26 of the lower end hardware 20 is the inner seat 3 in the upper end hardware 30.
4 shows an example in which a waterproof rubber ring 87 is mounted between the outer peripheral seat 27 of the lower metal fitting 20 and the chamfer 36 of the upper end surface 35 of the upper metal fitting 30.

FIG. 8 schematically shows a bending test of a joint portion of a steel pipe according to the present invention. In the joint of the steel pipe pile of the present invention, the bending moment of the joint part is transmitted by the screw part, and the material of the joint metal such as the lower metal part 20 and the upper metal part 30 has a raw pipe strength of 50 to 50 mm. 60kgf / m
In the case of m ² , 80 kgf / mm ² grade steel is used and welded to a steel pipe pile. The strength of the joint shall be such that the cross section edge yield moment at the dangerous section is not less than the cross section edge yield moment of the steel pipe pile, the total plastic moment at the dangerous section is not less than the total plastic moment of the steel pipe pile, and the screw edge shear yield The moment should be equal to or greater than the total plastic moment of the steel pipe pile. The cross-sectional rigidity of the joint is equal to or higher than the cross-sectional rigidity of the steel pipe pile.

As shown in FIG. 8, a steel pipe pile (base pipe) 10
0, 110 with the joint portion 120 at the center,
1 and two positions 122, 122 sandwiching the joint 120
A load 124 is applied to the joint portion 12 via the load beam 123.
A bending property of 0 was tested. The test material is outer diameter 300mm,
FIG. 9 shows the relationship between bending moment and displacement using a steel pipe pile made of SKK490 material having a thickness of 19.5 mm. In this test, the gap between the lower end face of the lower end metal part and the inner peripheral seat of the upper end metal part was set at 5 m in consideration of the allowable value of the joint connection at the site.
m. The solid line in FIG. 9 is a test value, and the broken line is a calculated value. Both the edge yield bending moment My, the total plastic moment Mp, and the cross-sectional rigidity of the joint exceed the properties of the raw pipe,
It shows excellent properties.

FIG. 10 shows another embodiment of the joint of the present invention. A lower end metal fitting 40 attached to a lower end of the steel pipe pile 100;
The upper metal part 50 attached to the upper end of the steel pipe pile 110 is combined. The lower end metal part 40 is welded and joined 101 to the steel pipe pile 100, and a cylindrical part 45 having an outer diameter of the screw bottom diameter is formed at the tip of the male screw 42. The lower end surface 46 is perpendicular to the axis of the steel pipe pile. A seal seat 47 is provided at the rear end of the male screw 42.

The metal fitting 50 at the upper end of the steel pipe pile 110 is welded and joined to the steel pipe pile 110, and a female screw 53 is provided on the inner diameter. An inner cylindrical surface 55 is formed below the female screw 53, and the cylindrical portion 45 below the male screw enters. The male screw 42 and the female screw 53 are formed as parallel threads having no taper, and are three or more threads. Parallel screws can be joined with lower torque than taper screws. In the case of a multi-thread screw, the lead in the axial direction during one rotation is multi-thread times the screw pitch. Therefore, quick screwing can be performed.

When the male screw 42 is screwed into the female screw 53,
Since the cylindrical portion 45 serves as a guide along the inner diameter of the female screw 53 before screwing, centering of the upper and lower piles is easy. By screwing, the lower end face 46 of the lower end metal part 40 and the inner peripheral seat 56 of the upper end metal part 50 are brought into close contact with each other, so that the strength and bending rigidity of the joint of the steel pipe pile can be significantly increased.

A concave hole 48 is provided in the outer peripheral surface of the cylindrical portion 45 of the lower metal fitting 40, and the cylindrical wall 54 of the upper metal fitting 50 is formed.
Is provided with a set bolt mounting hole 58. As shown in FIG. 11, the set bolt mounting hole 58 faces the concave hole 48, and the set bolt 60 is inserted into the set bolt mounting hole 58.
To form a detent between the lower pile and the upper pile so that the male screw 42 does not come out even if the upper pile is reversed. FIG.
FIG. 12 is a cross-sectional view taken along the line BB of FIG. This example shows a case where the screw is a four-start screw. A pair of set bolt mounting holes 58 are provided on the cylindrical wall 54 of the upper end hardware 50 symmetrically with respect to the center point. In the lower metal part 40, four pairs of concave holes 48, that is, eight pairs of concave holes 48 are arranged at equal intervals on the circumference of the circle. In this way, when the lower end metal part is reversed within 45 degrees of the central angle (within one eighth of the circumference), one of the concave holes 48 and the set bolt mounting hole 58 face each other. Generally, in the case of an N-thread, N or more pairs of concave holes 48 may be arranged on the circumference. With this configuration, the set bolt can be set by reversing the axial movement amount of one half or less of the screw pitch, and the relationship between the diameter of the concave hole, the arrangement position and the diameter and the arrangement position of the set bolt can be accurately determined. Can be well defined. Also, since the screw pitch is usually about 8 mm,
This can be achieved by returning the screw within 4 mm in the axial direction.
Thus, the clearance of the joint portion in the above-mentioned construction is within the allowable value (5 mm), and sufficient joint strength can be secured.

Although this embodiment shows an example in which the concave hole 48 is a circular hole and is not a through hole, a through hole or a circumferential concave may be used instead of the concave hole depending on the conditions of use of the steel pipe pile. It does not limit the use of grooves, axial grooves, or any other deformation. Also, the position of the set bolt mounting hole 58,
The number, size, etc. are not limited to the above embodiment,
Spare holes may be provided. FIG. 13 is a perspective view showing the screwing of the set bolt.

FIGS. 14 and 15 are explanatory diagrams of centering of the upper and lower piles. Upper metal part 50 of lower pile and lower metal part 4 of upper pile
If the axis does not coincide with 0, even a small deviation of the axis causes a large gap 70 at the joint end in a large diameter pile. For example, when the vertical accuracy of the lower pile is 1/200, the diameter is 600 mm.
In the pile, the gap 70 at the joint joining surface is 3 mm. The screw cannot be joined unless the four points 71, 72, 73, 74 shown in FIG. 15 engage simultaneously. In the present invention, one or both of the cylindrical portion at the distal end of the male screw at the lower end metal part and the inner cylindrical portion at the distal end of the female screw at the upper end metal part, and the multi-thread structure of the present invention provide a synergistic effect. Dispensing is extremely easy and reliable. Also, multi-threaded screws have very large leads and are quick to join. Therefore, the joint for steel pipe piles of the present invention is labor-saving, time-saving, safe, reliable, highly reliable, and optimal for rapid construction.

Further, the lower cylindrical part of the lower metal part is shown in FIG.
As shown in FIG. 6, when the pile 100 is lifted upward 131 by the lifting device 130, the screw does not come into contact with the floor surface 132 and the screw portion is protected.

[0035]

Since the joint for steel pipe piles of the present invention is constructed as described above, the following excellent effects can be obtained. In other words, there is a self-centering action of the steel pipe pile, and the construction time for connecting the steel pipe pile on site can be reduced. In addition, the construction can be quickly and accurately performed without being affected by the construction accuracy of the lower pile. The engagement of the screws can be extremely smooth,
Labor-saving and reliable construction is possible, and joint quality can be improved.

Further, in another embodiment of the present invention, the upper and lower piles can be easily centered and screwed in easily without damaging the thread portion when the pile is lifted, and the joining and the like can be easily performed. Accurate pile driving is possible, and the joint does not come off even when the pile is reversed.

[Brief description of the drawings]

FIG. 1 is a side view and a longitudinal sectional view of a joint according to an embodiment.

FIG. 2 is a plan view of a screw start end portion of the joint according to the embodiment.

FIG. 3 is a plan view of a thread start end of a conventional joint.

FIG. 4 is an explanatory view of a joining step of the joint according to the embodiment.

FIG. 5 is an explanatory diagram of a joining process of the joint according to the embodiment.

FIG. 6 is an explanatory view of a joining process of the joint of the embodiment.

FIG. 7 is a partial longitudinal sectional view showing a joint state of the joint according to the embodiment.

FIG. 8 is an explanatory diagram of a bending test of the joint of the example.

FIG. 9 is a graph showing the bending performance of the joint of the example.

FIG. 10 is a longitudinal sectional view of a fitting in another embodiment.

11 is a longitudinal sectional view of the fitting in the embodiment shown in FIG. 11;

FIG. 12 is a view on arrow AA of the embodiment of FIG. 11;

FIG. 13 is a perspective view of the embodiment of FIG. 11;

FIG. 14 is an explanatory diagram of centering of a fitting.

FIG. 15 is an explanatory diagram of centering of a fitting.

FIG. 16 is an explanatory view of lifting a pile.

[Explanation of symbols]

 Reference Signs List 20 lower end hardware 21 upper cylinder 22 groove 23 lower cylinder 24 male screw 25 cylindrical part 26 lower end surface 27 outer peripheral seat 28 hole or notch 30 upper end hardware 31 outer peripheral part 32 circumferential groove 33 female screw 34 inner seat 35 upper end face 36 chamfer 37 stop Water rubber ring 38 Inner surface cylindrical portion 39 Screw start end 40 Lower end hardware 42 Male screw 45 Cylindrical portion 46 Lower end 47 Upper end surface 48 Concave hole or groove 50 Upper end hardware 53 Female screw 54 Cylindrical wall 55 Inner surface (cylindrical surface) 56 Inner Peripheral seat 58 Set bolt mounting hole 60 Set bolt 70 Clearance 71, 72, 73, 74 points 100, 110 Steel pipe pile 101, 111 Welding joint 120 Joint part 121 Support part 122 Load point 123 Beam 124 Load 130 Lifting tool 131 Lifting 132 Floor surface

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masanori Shimizu 1-1-1, Kawasaki-cho, Handa-shi, Aichi Prefecture Inside the Chita Works of Kawasaki Steel Works (72) Inventor Koichi Okita 1-1-1-1, Kawasaki-cho, Handa-shi, Aichi Prefecture Kawasaki Inside the Chita Works of Iron and Steel Corporation

Claims (7)

[Claims] 1. A male cylinder having a male thread and a female cylinder having a female thread, each of which is provided at an end of a steel pipe pile,
A joint joint for steel pipe piles, wherein the screw is a multi-threaded screw having three or more parallel threads, and a cylindrical portion having an outer diameter that is loosely fitted to the inner diameter of the female screw is provided at the tip of the male-side cylindrical body. 2. The joint according to claim 1, wherein an inner cylindrical portion is provided at the distal end of the female-side cylindrical body to loosely fit the outer diameter of the male screw, instead of the cylindrical portion. 3. The joint according to claim 1, wherein an inner cylindrical portion which is loosely fitted to an outer diameter of the male screw is provided at a distal end of the female side cylindrical body. 4. The joint according to claim 1, wherein an inner peripheral seat with which the tip of the cylindrical portion comes into contact is provided on the inner surface of the female cylinder. 5. The steel pipe according to claim 2, wherein an outer peripheral seat at which a tip of the inner cylindrical portion abuts directly or via a waterproof rubber ring is provided on an outer surface of the male-side cylindrical body. Joints for piles. 6. The female cylinder according to claim 1, wherein a concave groove or a concave hole is provided on an outer periphery of the cylindrical portion, and a mounting hole for a set bolt to be fitted into the concave groove or the concave hole is provided in the female side cylinder. 3,
6. A joint for steel pipe piles according to 4 or 5. 7. A pair of mounting holes for the set bolts are provided symmetrically with respect to the center point of the cylindrical body, and at least N pairs of the concave holes are arranged at equal intervals on the circumference with respect to the center point of the cylindrical body. The joint for steel pipe piles according to claim 6. However, N is the number of threads of the multi-thread screw.