JP5762853B2 - Steel pipe joint structure - Google Patents

Description

  The present invention belongs to the technical field of a joint structure in which steel pipes are joined and connected in the axial direction.

Conventionally, applications for connecting steel pipes by connecting them in the axial direction exist in a wide range of technical fields.
For example, in the field of placing steel pipe piles, or in the construction field of the pipe roof construction method that is carried out when the impact of the live load of the ground is great when excavating and constructing a tunnel, and in addition to the sabo dam (slit dam) using steel pipes In the construction field and the like, various joint structures and joint methods have been implemented for connections that add steel pipes in the axial direction.
As a prior art, for example, the “steel pipe pile connection structure” disclosed in the following Patent Document 1 joins a female / male cylinder to be fitted to each other at the end of each steel pipe pile to be connected. Fit inside the female cylinder. The male cylinder is provided with a ring-shaped circumferential belt member on the inner peripheral surface, and the circumferential belt member has screw holes at regular intervals in the circumferential direction. On the other hand, the male cylinder and the female cylinder to be fitted as described above are fixed in the circumferential direction from the center of the cylinder in the radial direction, and the pin holes whose radial center lines coincide with the respective screw holes in the circumferential belt-like member are constant in the circumferential direction. A plurality of devices are provided with an interval of. That is, as described above, the coupling pin is fitted into the pin hole having the center aligned, and the bolt is further inserted through the bolt hole penetrating the center of the pin, and the circumference installed on the inner peripheral surface of the male cylinder. The pin is fixed by screwing it into the screw hole of the belt-shaped member, thereby achieving the purpose of steel pipe pile connection.

  By the way, the outer diameter of the steel pipe, which is the object of the present invention, ranges from about φ200 mm for small ones to as wide as φ2000 mm for large ones. In addition, the length of one unit of the steel pipe is usually about 6 m considering the ease of land transportation and construction. Therefore, the required condition for this type of steel pipe joint structure is that the above-mentioned unit length steel pipe can be easily and quickly added in the axial direction at the construction site, and the joint strength (connection strength) ). The number of steel pipe joints that work on the construction site is enormous, the performance of the joint structure is good, the ease of assembly work and the good workability are the results of the construction quality and performance of steel pipe piles and pipe roofing methods, and This is because the construction period greatly affects the construction period and the construction cost.

JP 2009-138382 A

Like the “steel pipe pile connection structure” disclosed in the above-mentioned Patent Document 1, in the case of a joint that joins the steel pipe by inserting a coupling pin in the radial direction of the steel pipe fitted in the inner and outer double, In addition, considering the accuracy (tolerance) at the time of manufacture, the diameter of the pin hole provided in the steel pipe needs to be slightly larger than the outer diameter of the coupling pin, and there is a slight gap between them. (Fitting tolerance) must be provided. Similarly, it is inevitable to provide a slight gap (fitting tolerance) between the steel pipes (outer joint pipe and inner joint pipe) fitted in the inner and outer doubles.
Therefore, for the purpose of confirming the coupling performance of the pin, a structure in which a steel pipe that has been inserted into a cylindrical coupling pin described in the above-mentioned Patent Document 1 and is fitted to the inner and outer doubles is coupled by a pin and connected. The results of testing the load bearing performance in the manner will be described.

11 shows a joint structure in which a cylindrical pin 60 is inserted into the pin holes 2c and 3c of the steel pipes 2 and 3 fitted in the inner and outer doubles and the steel pipes 2 and 3 are connected to each other. When a load resistance performance test is performed in which P is loaded and the pin 60 resists, the rotational behavior of the pin is slightly exaggerated.
When a large tensile force P is applied to the steel pipes 2 and 3 fitted in the inner and outer doubles, the fitting tolerance between the diameters of the pin holes 2c and 3c and the outer diameter of the coupling pin 60, and the inner and outer doubles are fitted. Due to the fitting tolerance between the steel pipes 2 and 3, rotational behavior occurs in the coupling pin 60, the contact area between the pin 60 and the steel pipes 2 and 3 is reduced, and the performance to transmit the load sufficiently and sufficiently is lowered. As a result, it was confirmed that the load could not be borne. When the pin 60 rotates, the pin 60 moves so as to come out of the pin holes 2c and 3c, and it has been confirmed that a retaining bolt for fixing the pin 60 is necessary.

The results of the load bearing performance test in FIG. 11 are as shown in the load-deformation diagram of FIG. 12 with the load bearing performance indicated by a dotted line. The localized load of the cylindrical pin 60 is a displacement of 15 mm in the axial direction of the steel pipe. It was about 350 KN in the vicinity, and after that it was confirmed that a collapse phenomenon was exhibited.
With respect to the rotational behavior of the cylindrical pin 60, in the case of Patent Document 1, a retaining bolt for fixing the pin is employed, but a large load is applied to the bolt due to the rotational behavior of the pin 60 described above. It is clear that it works.
Therefore, if the shaft diameter of the retaining bolt and the effective diameter of the screw are made sufficiently large in consideration of the large load described above, the diameter of the bolt hole provided in the central portion of the coupling pin for passing this retaining bolt increases. I have to. As a result, the cross-sectional defect of the coupling pin is as large as the diameter of the bolt hole, so the outer diameter of the pin must be further increased in order to ensure the cross-sectional area required for the coupling pin. If it does so, the diameter of the pin holes 2c and 3c provided in the steel pipes 2 and 3 fitted in the inner and outer doubles will be increased, and a cross-sectional defect of the steel pipes will be increased.
Of course, when the inner and outer steel pipes 2 and 3 bear a large load, the number of connecting pins to be used increases, so that there is a problem that the cross-sectional defect of the steel pipe becomes larger.

Therefore, an object of the present invention is that the pin that couples the joint pipe fitted in the inner and outer doubles behaves in a manner that it rotates in the pin hole by a tensile force or a compressive force applied to the joint pipe fitted in the inner and outer doubles. When the pin is turned by a pulling force or a compressive force applied to each joint pipe in a pin hole having a fitting tolerance, the above-mentioned wrinkle is formed on the outer side. It hits the outer peripheral surface of the joint pipe, resists rotational behavior, prevents rotation, and maintains the contact area (contact state) between the pin edge of each pin hole of the inner and outer joint pipe and the pin to transmit the load. It is an object of the present invention to provide a steel pipe joint structure in which a mechanism that securely holds the load and a pin with a hook is configured to safely bear the load on the joint pipe.
The next object of the present invention is to prevent the above-mentioned hooked pin itself from rotating due to the load of the joint pipe fitted in the inner and outer doubles, and to prevent the movement to come out of the pin hole. Reduces the pull-out force acting on the retaining bolt that fixes the pin with the flange, reduces the outer diameter required for the retaining bolt, and consequently reduces the diameter of the bolt hole provided in the center of the flanged pin. It is an object of the present invention to provide a steel pipe joint structure that can be expected to have a virtue of virtue of reducing the cross-sectional defect of the pin and reducing the outer diameter of the pin that secures the cross-sectional area required for the coupling pin.

As means for solving the above-described problems of the prior art, the joint structure of a steel pipe according to the invention described in claim 1 is:
An outer joint pipe 2 is attached to the end of one steel pipe 1 to be connected, and an inner joint pipe 3 fitted into the hollow portion of the outer joint pipe 2 is attached to the end of the other steel pipe 1, and the outer joint pipe 2 is attached. In the joint structure in which the inner joint pipe 3 is fitted inside and the steel pipes are connected to each other,
Each of the inner joint pipe 3 and the outer joint pipe 2 is provided with a plurality of pin holes 2c and 3c which are arranged so that the centers of the holes coincide with each other when the joint pipes are fitted together. ,
A female screw member 5 having a screw hole 5b on the inner peripheral surface of the inner joint pipe 3 has a positioning step 5c formed on the outer surface of the female screw member 5 in the pin hole 3c of the inner joint pipe 3. Fitted to the inner edge, and fixed in an arrangement in which the center of the screw hole 5b is aligned with the center of the pin hole 3c of the inner joint pipe 3,
The coupling pin 6 or 6 ′ to be inserted into the pin holes 2 c and 3 c of both joint pipes, in which the inner joint pipe 3 is fitted into the hollow part of the outer joint pipe 2 and the center is aligned, is disposed at the outer end. A pin with a flange having a flange portion 6b that abuts on the outer peripheral surface of the outer joint pipe 2, and a bolt through hole 6a is penetrated in the center, and the pin 6 or 6 'with the flange is a pin hole 2c of the outer joint pipe 2. the tip surface to the pin hole 3c of the inner joint pipe 3 is inserted until the surface contact to an outer surface of the female screw member 5 from
A retaining bolt 7 inserted through the bolt through hole 6a of the hooked pin 6 is screwed into the screw hole 5b of the female screw member 5 and fastened to fix the hooked pin 6, and the outer joint pipe 2 and The fitting state of the inner joint pipe 3 is combined.

The invention described in claim 2 is a steel pipe joint structure according to claim 1,
The female screw member 5 ′ includes a screw cylinder 5a that stands up around the screw hole 5b. The screw hole 5b is threaded so as to continue to the tip of the screw cylinder 5a. Further, a counterbore 6c having a depth and a shape for receiving the screw cylinder 5a is formed on the front end surface thereof.
The invention described in claim 3 is the steel pipe joint structure according to claim 1 or 2,
The female screw member is configured as an independent member that is independently fixed to the inner peripheral surface of the inner joint pipe 3 for each position of the pin hole 3 c of the inner joint pipe 3, or a pin hole is formed on the inner peripheral surface of the inner joint pipe 3. It is comprised by the ring-shaped member fixed along the circumferential direction arrangement | sequence, The screw hole 5b is formed in the arrangement | positioning which corresponds to the center of each pin hole 3c of the inner joint pipe 3, It is characterized by the above-mentioned.

In the steel pipe joint structure according to the first to third aspects of the present invention, the outer joint pipe 2 and the inner joint pipe 3 fitted into the hollow portion thereof are inserted into the pin holes 2c and 3c of the respective inner joint pipes 3 and pins for connecting both pipes are provided. The outer joint pipe 2 and the inner joint pipe 3 are subjected to a strong tensile load or compressive load in the axial direction because the flanged pin 6 (or 6 ′, hereinafter the same) is provided with the flange 6b at the outer end. In this case, the flanged pin 6 strongly resists by the action of the flange portion 6b hitting or catching on the outer peripheral surface of the outer joint pipe 2, and firmly holds the coupling state of the joint pipes 2 and 3 fitted in the inner and outer double structures. Demonstrates strong and stable joint performance.
Concretely, it demonstrates based on the result of having tested the load-bearing performance at the time of couple | bonding the joint pipes 2 and 3 fitted by the inner and outer double with the pin 6 with a hook. FIG. 10 is a pin 6 with a flange having a flange portion 6b, and the outer joint pipe 2 and the inner joint pipe 3 fitted to the inner / outer double structure are coupled to each other, and the rotational behavior of the pin that occurs when the tensile load P acts. Is a little exaggerated. As is clear when this is compared with the rotational behavior of the cylindrical wrinkleless pin 60 shown in FIG. 11, the wrinkled pin 6 includes the outer joint pipe 2 subjected to the tensile load P and the pin hole 3 c of the inner joint pipe 3. Even if a rotational moment is received by the hole edge of 2c, since the flange portion 6b of the flanged pin 6 abuts (or gets caught) against the outer peripheral surface of the outer joint pipe 2, the rotational behavior itself is prevented. As a result, the joint state of the joint pipes 2 and 3 by the flanged pin 6 transmits the stress while maintaining a stable contact state with the rims of the pin holes 2c and 3c of the inner and outer joint pipes 2 and 3. High strength and stable joint performance.

Incidentally, the load bearing performance of the joint by the pin 6 with the hook shown in FIG. 10 is as shown by the solid line in FIG. 12 showing the test result, and contrasted with the dotted line showing the load bearing performance of the pin 60 without the hook. The difference between them will be clear. That is, it is clear that the localized load due to the pin 6 with the hook reaches about 470 KN, and the soundness is maintained even when the displacement reaches 20 mm, and excellent load bearing performance is exhibited as a joint structure between steel pipes.
As described above, since the rotational behavior of the hooked pin 6 is effectively prevented by the hooked portion 6b, the pulling load borne by the bolt 7 fixing the hooked pin 6 is small. Therefore, the outer diameter required for the bolt 7 can be small. Therefore, the diameter of the bolt hole 6a provided in the pin 6 with the hook is small, and the cross-sectional defect is small, and the outer diameter of the pin that secures the cross-sectional area required for the pin 6 with the hook is also reduced. As a result, the diameters of the pin holes 2c and 3c provided in the outer joint pipe 2 and the inner joint pipe 3, respectively, can be reduced, and the cross-sectional defects of the outer joint pipe 2 and the inner joint pipe 3 can be reduced. can get.

In addition, since the joint structure of the present invention is a mechanical joint, quality control in the field is easy, and a simple and quick assembly operation of the joint can be performed. Specifically, in the case of a steel pipe having an outer diameter of about 1000 mm, one joint operation can be completed in about 15 to 20 minutes, which can greatly contribute to shortening the construction period.
Of course, in the joint structure of the present invention, when it is necessary to disassemble / separate the joint, the bolt 7 is loosened and removed, and the hooked pin 6 is removed from the pin holes 2c and 3c, and the inner joint pipe 3 is removed. Can be easily separated from the outer joint pipe 2 and separated and disassembled. Therefore, it is possible to easily redo the construction for pushing the steel pipe 1 into the ground, replace the steel pipe 1, or collect the steel pipe 1. At that time, since the inner joint pipe 3 and the outer joint pipe 2 are not damaged, there is also an effect that no trouble is caused in the reuse of the steel pipe 1.

It is the front view which showed the state by which the steel pipe connected by implementing the joint structure of this invention was equipped with the inner joint pipe and the outer joint pipe, and was put in a series of arrangement | positioning. It is the front view which showed the state with which the steel pipe of FIG. 1 was connected by the joint structure of this invention. A is an enlarged sectional view taken along line III-III indicated in FIG. 2, and B is a sectional view showing different embodiments from the same viewpoint. It is sectional drawing which expanded a little at the stage in the middle of fitting the joint pipe inside and outside of the steel pipe to connect. FIG. 5 is a cross-sectional view showing a state in which the inner and outer joint pipes are fitted from the state of FIG. 4 and coupled with a hooked pin as a view taken along line VV in FIG. 2. FIG. 6A is a cross-sectional view showing an enlarged view cut along the VI-VI line arrow indicated in FIG. 5, and FIG. 6B is a cross-sectional view showing an embodiment different from FIG. A is a front view showing an example of a pin with a hook, with the right half cut away, and B is a front view showing different embodiments of the pin with a hook. A is a front view showing an example of the female screw member with the right half cut away, and B is a cross-sectional view showing another embodiment of the female screw member with the right half cut off. A is a front view showing an example of a retaining bolt, and B is a plan view showing the bolt head. It is explanatory drawing which exaggerated and showed the behavior at the time of the outer joint pipe | tube and the inner joint pipe | tube connected with the pin with a hook which has a collar part receiving the extraction load P. It is explanatory drawing which exaggerated and showed the behavior at the time of the outer joint pipe | tube and the inner joint pipe | tube connected with the cylindrical pin which does not have a collar part receiving the extraction load P. It is the load-displacement curve figure which compared the load bearing performance of the pin with a hook and a pin without a hook.

The joint structure of the steel pipe which concerns on this invention attaches the outer joint pipe 2 to the edge part of the one steel pipe 1 to connect, and it fits in the hollow part of the said outer joint pipe 2 in the edge part of the other steel pipe 1. 3, and the steel pipes 1 and 1 are connected to each other by fitting the inner joint pipe 3 into the hollow portion of the outer joint pipe 2.
Each of the inner joint pipe 3 and the outer joint pipe 2 is provided with a plurality of pin holes 2c and 3c which are arranged so that the centers coincide with each other when the pipes are fitted together.
A female screw member 5 provided with a screw hole 5 b is formed on the inner peripheral surface of the inner joint pipe 3, and a positioning step portion 5 c formed on the outer surface of the female screw member 5 is formed on the pin hole 3 c of the inner joint pipe 3. It fits into the inner edge, and is fixed in an arrangement in which the center of the screw hole 5b coincides with the center of the pin hole 3c of the inner joint pipe 3.
The inner joint pipe 3 is fitted into the hollow portion of the outer joint pipe 2, and the coupling pin 6 is inserted into the pin holes 2c and 3c of both joint pipes whose centers are matched. The coupling pin 6 is a pin with a hook having an outer end formed with a hook part 6b that abuts against the outer peripheral surface of the outer joint pipe 2. A bolt through hole 6a is passed through the center part of the pin 6 with a hook. ing. Flanged pin 6 from the pin hole 2c of the outer joint pipe 3 to the pin hole 2c of the inner joint pipe 3, plugging to the tip surface is in surface contact to an outer surface of the female screw member 5.
Further, a retaining bolt 7 is inserted into the bolt through hole 6a of the hooked pin 6, and screwed into the screw hole 5b of the female screw member 5 to fasten the hooked pin 6, so that the outer joint pipe 2 is fixed. And the fitting state of the inner joint pipe 3 are combined to achieve connection of the steel pipes 1 and 1.

The female screw member 5 ′ includes a screw cylinder 5a that stands up around the screw hole 5b, and the screw hole 5b is threaded so as to continue to the tip of the screw cylinder 5a. On the other hand, it is also preferable that the hooked pin 6 ′ is formed with a counterbore 6c having a depth and a shape for receiving the screw cylinder 5a on the tip surface.
Further, when the female screw member 5 or 5 ′ is configured as an independent member that is fixed to the inner peripheral surface of the inner joint pipe 3 independently for each position of the pin hole 3 c of the inner joint pipe 3 (see FIG. 3A). In addition, it is configured as a ring-shaped member that is fixed to the inner peripheral surface of the inner joint pipe 3 like a female screw member 50 shown in FIG. 3B, and the center is a pin for each position of each pin hole 3 c of the inner joint pipe 3. It is also preferable to implement a configuration in which a plurality of screw holes 5b are formed in an arrangement that coincides with the center of the hole 3c.

In addition, the steel pipe 1 which implements the joint structure of this invention is not restricted to a round pipe with a circular cross section. It can be implemented in exactly the same manner for connecting a square tube or an elliptic tube. In this case, the cross-sectional shape of the inner and outer joint pipes 2 and 3 is the same as that of the steel pipe 1.
Similarly, there is no reason why the cross section of the shaft portion of the pin member 6 or 6 'is limited to a circle. In particular, when the steel pipe is a square pipe, the cross-section of the pin material can also be implemented as a quadrangle (square or rectangular). A pin material having a polygonal cross section can also be used.
Furthermore, the form of the steel pipe is not limited to a straight straight pipe. The present invention can be applied to the connection of curved or bent steel pipes as required.

Next, the present invention will be described based on the illustrated embodiment.
First, FIG. 1 and FIG. 2 show the two steel pipes 1 and 1 that move back and forth in the axial direction in the arrangement relationship before connection and after connection. 3 to 6 show details of the joint structure.
In the case of this example, the unit length of the steel pipe 1 is about 6 m, the outer diameter is about 1000 mm, and the outer joint pipe 2 is attached to the end of the steel pipe 1 on the right side in the figure (left end part in the figure). An inner joint pipe 3 to be fitted into the hollow part of the outer joint pipe 2 is attached to the end of the left steel pipe 1 (right end in the figure). The steel pipes 1, 1 that move back and forth in the left-right direction are connected by closely fitting the inner joint pipe 3 into the hollow portion of the outer joint pipe 2 (FIG. 2).
In addition, although the steel pipe 1 shown in FIG. 1 and FIG. 2 has shown the structure which attached the outer joint pipe 2 to one side edge part, and the inner joint pipe 3 to the other edge part alternately, in this limit, Absent. As a different embodiment, the outer joint pipe 2 is attached to both ends of one steel pipe 1, and the inner joint pipe 3 to be fitted into the hollow portion of the outer joint pipe 2 is attached to both ends of the other steel pipe 1. This type of steel pipes 1 and 1 can also be implemented in a configuration in which they are connected in combination in a staggered arrangement on the front and rear.

In the case of the embodiment shown in FIGS. 4 to 6, the pipe wall thickness of the steel pipe 1 is about 10 mm, whereas the outer joint pipe 2 and the inner joint pipe 3 are superior in strength to the steel pipe 1. Furthermore, the tube wall thickness is set to 16 mm, which is slightly thick, and the length is processed into a steel pipe material having a length of about 380 mm. The inner diameter of the outer joint pipe 2 is φ984 mm, whereas the outer diameter of the inner joint pipe 3 is φ976 mm, and the inner and outer joint pipes 3 and 2 are closely connected with a clearance (fitting tolerance) of about 4 mm on the entire circumference. It is set as the structure fitted. The base end portions of the joint pipes 2 and 3 are abutted with the end portions of the steel pipe 1 and are integrally joined by whole circumference welding.
A configuration in which the distal end portion 2a of the outer joint pipe 2 hits the step portion 3b having a thick cross section formed at the outer peripheral portion of the proximal end portion of the inner joint pipe 3 is a state where the fitting of both pipes is completed. (See FIG. 5).

  In the steel pipes 1, 1 having the above-described configuration, the inner joint pipe 3 is fitted into the hollow portion of the outer joint pipe 2, and the end portion 2 a of the outer joint pipe 2 is brought into contact with the step portion 3 b of the inner joint pipe 3. An intermediate portion of both joint pipes 2 and 3 in the axial direction of the pipe (FIGS. 1 and 2 show a substantially central portion, but not limited to this position), and at a certain interval in the circumferential direction. In an arrangement (see FIG. 3) sharing a radially outward center line N from the center O of both joint pipes 2 and 3 at a plurality of positions (positions equivalent to 18 in FIG. 3), the aperture is about φ49. Pin holes 2c and 3c having the same size are provided (see FIGS. 4 and 5).

In Example 1 shown in FIGS. 3A and 4 to 6A, a screw hole 5b is provided at the center as shown in detail in FIG. 8A for each position of each pin hole 3c on the inner peripheral surface of the inner joint pipe 3. The flat-plate-shaped (disk-shaped) female screw member 5 is made the same by aligning the center of the pin hole 3c and the center of the screw hole 5b for each position of each pin hole 3c of the inner joint pipe 3. It is placed in close contact with the inner surface and fixed by welding.
Incidentally, the work of installing the female screw member 5 on the inner peripheral surface of the inner joint pipe 3 is performed precisely as work in a factory or the like before the work process of joining the inner joint pipe 3 to the end of the steel pipe 1. deep.

Here, the thickness dimension of the flat shape of the female screw member 5 will be described. For example, when constructing a pipe roof method or embedding a steel pipe pile, it is common to pass a hollow digger in the hollow portion of the steel pipe 1 and digging in the hollow digging auger. Proceed with the indentation process.
Therefore, the female screw member 5 is formed in a thin disk shape as in the embodiment shown in FIG. 8A, and the thickness of the flat plate (the height of the protrusion from the inner peripheral surface of the inner joint pipe 3). Dimension) does not hinder the operation of entering and exiting the digging auger, and satisfies the conditions for exhibiting necessary and sufficient screwing strength for bolt tightening described later. Incidentally, the plate | board thickness of the internal thread member 5 shown to FIG. 8A is formed in the thickness of 12 mm as an example.
However, in the configuration in which the screw hole 5b is processed into a flat plate having a thickness of 12 mm, there is a concern that the effective screw length is insufficient for the strength of the screw connection from the viewpoint of strength. Therefore, it is effective to use the female screw member 5 ′ shown as a different embodiment in FIG. 8B as means for ensuring the effective screw length sufficiently and sufficiently. This female screw member 5 'has a configuration in which a screw cylinder 5a protruding from the outer surface is provided, and the screw hole 5b extends to the tip of the screw cylinder 5a. The screw cylinder 5 a rises from the outer surface of the female screw member 5 ′ toward the pin hole 3 c of the inner joint pipe 3. Therefore, as in Example 2 shown in FIG. 6B, the screw cylinder 5 a does not hinder any operation for entering and exiting the digging auger. However, the inner joint pipe 3 on the relationship between fitting into the hollow portion of the outer joint pipe 2, is due to the screw cylinder 5a, it is important to configure within the depth of the pin hole 3 c of the inner joint pipe 3. In the case of the second embodiment shown in FIG. 6B, the screw cylinder 5a is 5 mm as an example, and the effective screw length of the female screw hole 5b is extended to 17 mm.
In the embodiment shown in FIG. 8B, the stepped portion 5c found on the outer surface of the female screw member 5 ′ (the surface in contact with the inner peripheral surface of the inner joint pipe 3) is different from the pin hole 3c of the inner joint pipe 3. It is the level | step difference for positioning formed in the same diameter. When the female screw member 5 ′ is aligned with the center of the pin hole 3 c of the inner joint pipe 3, if the positioning step 5 c is fitted to the lip of the pin hole 3 c, positioning and temporary fixing can be achieved and stability is achieved. Therefore, it is convenient for the work of fixing the female screw member 5 ′ to the inner peripheral surface of the inner joint pipe 3 by all-around welding.

However, the structure of the female screw member is fixed as an independent flat plate member for each position of each pin hole 3c on the inner peripheral surface of the inner joint pipe 3 as in the embodiment shown in FIGS. 3A, 8A and 8B. It is not restricted to the structure to install.
As in the embodiment illustrated in FIG. 3B, a female formed as an annular material (ring-shaped member) at a position along the circumferential line in which the pin holes 3 c are arranged on the inner circumferential surface of the same inner joint pipe 3. It can also be implemented in the same manner with a configuration in which the screw member 50 is fixed and installed. Of course, the female screw member 50 configured as an annular member (ring-shaped member) is provided with a screw hole at each position that coincides with the center of each pin hole 3c provided at intervals in the circumferential direction of the inner joint pipe 3. Alternatively, it is implemented with a configuration in which the screw cylinder is raised concentrically with the screw hole.
However, the female screw member 50 configured as the annular member (ring-shaped member) is not limited to a configuration implemented in a complete circular configuration. For example, as a configuration divided into two or three parts in the circumferential direction, each divided piece is fixed and installed in a continuous arrangement in a row in the circumferential direction of the inner peripheral surface of the inner joint pipe 3, and finally in an annular shape It is also convenient to implement in a completed configuration. With such a division type, in the case where each screw hole and a series of screw cylinders are erected on the outer peripheral surface of the annular female screw member 50, the inner joint pipe 3 is fitted into the inner peripheral surface. This is preferable because the work to be performed becomes easy.

The preparation and work of each component described above are usually performed precisely as factory processing. Then, the completed steel pipe 1 is brought into the construction site such as a pipe roof construction method or a steel pipe pile, and the connection between the steel pipes 1 and 1 is performed in the following manner while the steel pipe 1 is pushed into the ground. Do.
In the case of the embodiment shown in FIGS. 1 and 2, the steel pipe 1 in the next order (the steel pipe located on the right side) is attached to the inner joint pipe 3 attached to the rear end of the steel pipe 1 on the left side in the drawings constructed in advance. ) At the left end, and the outer joint pipe 2 is attached in a relative manner. The inner and outer joint pipes 2 and 3 determine the positional relationship between the corresponding pin holes 2c and 3c, and the fitting operation of the inner and outer joint pipes 3 and 2 is advanced so that the center lines of both pipes coincide with each other. . When the fitting operation of the inner and outer joint pipes 3 and 2 is proceeded in this way, the fitting in which the tip 2a of the outer joint pipe 2 hits the step 3b at the back end of the inner joint pipe 3 in the manner illustrated in FIGS. At the completion of alignment, the positions of the pin holes 2c and 3c of both joint pipes coincide. Therefore, the flanged pin 6 is inserted from the pin hole 2 c of the outer joint pipe 2 toward the corresponding pin hole 3 c of the inner joint pipe 3, and the tip of the flanged pin 6 is directed to the outer surface of the female screw member 5. Make contact.

In the case of Embodiment 1 shown in FIGS. 5 and 6A, the pin 6 with the hook is the one shown in FIG. 7A. The shaft portion of the hooked pin 6 has an outer diameter and a cross-sectional area large enough to withstand the load caused by the pushing force applied to the joint portion through the steel pipes 1 and 1 and the earth pressure of the ground. ing. For example, when the diameters of the pin holes 2c and 3c of the joint pipes 2 and 3 are φ49 mm as described above, the shaft portion outer diameter of the pin 6 with the flange has an average fitting tolerance of about 0.5 mm on the entire circumference. Thus, it is formed to have a diameter of about 48 mm. Further, a bolt through hole 6a having a diameter of 17 mm is provided in a penetrating state in the axial direction of the central portion of the pin 6 with the hook.
The flange portion 6b formed on the outer end portion (upper end portion) of the flanged pin 6 is such that when the shaft portion of the pin 6 is inserted into the pin holes 2c and 3c as described above, the tip of the pin 6 is female. At the same time as contacting the outer surface of the screw member 5, the flange portion 6 b comes into contact with the outer peripheral surface of the outer joint pipe 2 and stops. The flange portion 6b is also effective in preventing the rotation behavior when an external force such as earth pressure is applied to the joint portion and the rotation behavior described with reference to FIG. Demonstrate the function. The thickness of the flange portion 6b is as small as possible when the steel pipe 1 is pushed into the ground, and the frictional resistance with the ground is as small as possible, and the effect of preventing the rotational behavior is necessary to secure the connection strength of the steel pipes 1 and 1 described later. For example, a flat shape having a height (thickness) of 9 mm and an outer diameter of about 55 mm (a difference of 7 mm from the outer diameter of the pin) is formed so as to exhibit high strength and rigidity.

5 and 6A shows a connection state of a joint structure using the pin 6 having the shape and structure shown in FIG. 7A and the female screw member 5 having the shape and structure shown in FIG. 8A. This is also an embodiment of the invention according to claim 1.
That is, the inner joint pipe 3 is fitted into the hollow portion of the outer joint pipe 2, the centers of the pin holes 2c and 3c of both joint pipes 2 and 3 are aligned, and the shaft portion of the pin 6 with the flange is connected to the pin holes 2c and 3c. The tip is inserted into contact with the outer surface of the female screw member 5. After that, the bolt 7 for retaining is passed through the bolt through hole 6a of the hooked pin 6 and screwed into the screw hole 5a of the female screw member 5 and fastened to fasten the hooked pin 6, thereby fixing the outer joint pipe. 2 shows a joint structure in which an inner joint pipe 3 and 2 are joined.

On the other hand, the second embodiment shown in FIG. 6B is a connection of a joint structure using the pin 6 ′ having the shape and structure shown in FIG. 7B and the female screw member 5 ′ having the shape and structure shown in FIG. 8B. This shows a state, which corresponds to an embodiment of the invention according to claim 2.
As already described in paragraph 0022 above, from the viewpoint of the strength of the joint structure, in the screw hole 5a of the flat female screw member 5 shown in FIG. 8A, the effective screw length is insufficient for the screw joint strength. When there is a concern, it is effective to employ a configuration in which a screw cylinder 5a protruding to the outer surface is provided, such as the female screw member 5 ′ shown in FIG. 8B. Since the screw cylinder 5a rises from the outer surface of the female screw member 5 ′ toward the pin hole 3c of the inner joint pipe 3, as shown in FIG. The fitting of the inner joint pipe 3 and the outer joint pipe 2 is not hindered.
Corresponding to the form in which the female screw member 5 ′ shown in FIG. 8B has a screw cylinder 5a, the hooked pin 6 shown in FIG. 6B receives the screw cylinder 5a on its tip surface, and A counterbore 6c that makes the tip surface of the pin 6 come into close contact with the female screw member 5 is formed as a recess having a diameter larger than the outer diameter of the screw cylinder 5a and deeper than the protruding height of the screw cylinder 5a. Further, the flange 6b of the pin 6 with the hook has a counterbore 6d having a depth that allows the head of the bolt 7 inserted into the hole 6a to sink below from the upper surface of the flange 6b with the bolt through hole 6a as the center. It is formed as a recess having a diameter and depth slightly larger than the bolt head. Therefore, in the case of Example 2 shown in FIG. 6B, there is no concern that the head 7a of the bolt 7 causes harmful resistance when the steel pipe 1 is pushed into the ground.
As shown in FIG. 9, the bolt 7 used in the second embodiment of FIG. 6B has a wrench (not shown) that is a tool for turning the bolt 7 at the center of the upper surface of the cylindrical bolt head 7a. It is set as the structure which provided the hexagon hole 7b for rotating. The reason for using the bolt 7 having the cylindrical bolt head 7a is based on consideration of reducing the diameter of the counterbore 6d provided in the flange portion 6b of the pin 6 with the flange. Therefore, when the above consideration is not required, the shape of the head 7a of the bolt 7 is not limited to the illustrated cylindrical shape, and may be a square or hexagonal head. Alternatively, a countersunk head bolt having a plus or minus groove into which a screwdriver is inserted may be used.

In any of the first embodiment shown in FIG. 6A or the second embodiment shown in FIG. 6B, as the assembly (connecting) operation of the joint, the steel pipes 1, 1 arranged back and forth in the construction (pushing in) direction, etc. The inner joint pipe 3 is fitted to a predetermined position in the hollow portion of the outer joint pipe 2 so that the centers of the corresponding pin holes 2c and 3c of the joint pipes 2 and 3 are matched. Then, the flanged pin 6 or 6 ′ is inserted from the pin hole 2 c of the outer joint pipe 2 toward the pin hole 3 c of the inner joint pipe 3. As illustrated in FIGS. 5 and 6, the hooked pin 6 or 6 ′ enters the pin hole 2 c to 3 c and is the same as when the hook portion 6 b comes into contact with the outer peripheral surface of the outer joint pipe 2 and stops. At the time, the lower end surface of the scissor pin 6 or 6 ′ contacts the outer surface of the female screw member 5 through the pin hole 3 c of the inner joint pipe 3.
At this time, in the case of the embodiment 2 shown in FIG. 6B, the screw cylinder 5a of the female screw member 5 ′ is accommodated in a counterbore 6c provided in the distal end surface of the hooked pin 6 ′. The center of the screw hole 5b coincides with the center of the bolt through hole 6a of the pin 6 with the hook.

Subsequently, the bolt 7 for retaining is inserted into the bolt through hole 6a of the hooked pin 6 (or 6 ', hereinafter the same). Since the bolt 7 reaches the screw hole 5b of the female screw member 5 (or 5 ′, hereinafter the same), the bolt 7 is screwed into the screw hole 5b and fastened by turning the bolt 7 in the forward rotation direction. Retaining and fixing are achieved. By tightening the bolt 7 strongly, the flanged pin 6 is firmly fixed, and a firm connection (coupling) between the fitted outer joint pipe 2 and the inner joint pipe 3 is completed.
In the example of FIG. 3, the outer joint pipe 2 and the inner joint pipe 3 are provided with a pair of 18 pin holes 2c and 3c in the circumferential direction. Therefore, by inserting 18 hooked pins 6 in total into the respective pin holes 2c and 3c and fastening them firmly with bolts 7, the connection of the steel pipes 1 and 1 with the joint structure is necessary and sufficient strength and rigidity. To be achieved. Therefore, it is possible to realize a joint structure having strength and rigidity that can sufficiently withstand a large load such as earth pressure acting on the steel pipe 1. Moreover, the joint structure of the present invention is completed with a constant quality in a simple connection work.

According to the present invention, the joint of the steel pipes 1 and 1 arranged back and forth in the construction direction of the steel pipe (push-in direction or the like) is fitted to the outer joint pipe 2 and the inner joint pipe 3 attached to each steel pipe 1. A pin 6 with a hook for coupling is inserted into the corresponding pin holes 2c and 3c of the joint pipes 2 and 3, and the pin 6 with a hook is further firmly fastened and fixed with a bolt 7 for retaining. Therefore, connection work (joint assembly work) does not require any special skill, and connection with excellent strength and rigidity can be easily and quickly carried out with efficient work contents, and the request for shortening the construction period is fully met. It is done. In addition, it is suitable for field work because quality control is easy.
Needless to say, not only the push-in construction of the steel pipe 1 is stopped due to unexpected circumstances or due to changes in the construction conditions, but also when the existing steel pipe is forced to be pulled out, the bolt 7 is loosened and removed, By disengaging the attached pin 6 from the pin holes 2c and 3c and removing the inner joint pipe 3 from the outer joint pipe 2, disassembly and separation can be performed easily. Moreover, since the inner joint pipe 3 and the outer joint pipe 2 are not damaged at the time of dismantling / separation, there is no problem in the reuse of the steel pipe 1 and the economy is high.

Finally, the load resistance performance of the pin 6 with the hook connecting the inner and outer joint pipes 2 and 3 constituting the joint structure of the present invention, and the connection strength between the steel pipes, as shown in FIG. The contents of the load performance test will be described.
Although already briefly described in paragraph 0012, when the tensile load P is applied to the outer joint pipe 2 and the inner joint pipe 3 connected by the hooked pin 6 as shown in FIG. Rotation behavior occurs.
That is, when the outer joint pipe 2 and the inner joint pipe 3 receive a tensile load P, the pin 6 with a flange is subjected to the action of a rotational moment via the hole edges of the pin holes 3c and 2c of the inner and outer joint pipes 3, respectively. receive. In FIG. 10, the hooked pin 6 has a clockwise rotation behavior. However, since the flanged pin 6 has a flange 6b at the upper end, the flange 6b abuts against (or gets caught by) the outer peripheral surface of the outer joint pipe 2 and resists the rotational behavior. Prevent rotational behavior.
About the effect of rotation prevention by the said collar part 6b, it is as having shown the load-deformation performance with the continuous line in FIG. 12 which showed the result of the load bearing performance test. That is, in the case of the pin 6 with the hook of FIG. 10, the displacement extends to 20 mm and the localized load reaches about 470 KN.
On the other hand, the result of the load resistance performance test performed in the manner shown in FIG. 11 on the pin 6 ′ having a cylindrical shape and having no flange portion is as follows. As shown in FIG. 12, the load-deformation performance is indicated by a dotted line. It only shows an ultimate load of about 350 KN at about 15 mm.
As described above, the pin 6 with the flange having the flange portion 6b is particularly excellent in load bearing performance as compared with the pin 6 ′ having a cylindrical shape and not having the flange portion. Therefore, it is clear that the strength and rigidity of the steel pipe joint structure using the pin 6 with the flange is excellent.

  Although the present invention has been described based on the illustrated embodiments, the present invention is not limited to the configurations and functions of the embodiments. I would like to remind you that this is a technical idea that includes the scope of application and changes similar to design changes made by those skilled in the art as necessary.

DESCRIPTION OF SYMBOLS 1 Steel pipe 2 Outer joint pipe 2a Tip part 3 Inner joint pipe 3a Tip part 3b Step part 2c, 3c Pin hole 5, 5 ', 50 Female thread member 5a Screw cylinder 5b Screw hole 6, 6' Pin 6a with a bolt Bolt through hole 6b collar 6d counterbore 7 bolt 7a bolt head

Claims (3)

An outer joint pipe is attached to the end of one steel pipe to be connected, an inner joint pipe that fits into the hollow part of the outer joint pipe is attached to the end of the other steel pipe, and the inner joint pipe is fitted into the outer joint pipe. In joint structure that connects steel pipes together,
Each of the inner joint pipe and the outer joint pipe is provided with a plurality of pin holes arranged at intervals in the circumferential direction in which the centers of the holes coincide with each other when the joint pipes are fitted together.
A female screw member provided with a screw hole on the inner peripheral surface of the inner joint pipe is fitted with a positioning step formed on the outer surface of the female screw member to the inner edge of the pin hole of the inner joint pipe, fixed in said center of the screw hole to match the center of the pin hole of the inner joint pipe arrangement,
The coupling pin that is inserted into the pin hole of both joint pipes that are arranged so that the centers coincide with each other by fitting the inner joint pipe into the hollow part of the outer joint pipe should hit the outer peripheral surface of the outer joint pipe at the outer end. parts are flanged pin having a bolt through-holes are penetrating the central portion, the outer surface of the flanged pin from the pin hole of the outer joint tube to the pin hole of the inner joint tube distal end surface the female threaded member Until it touches the surface ,
A retaining bolt inserted through the bolt through hole of the hooked pin is screwed into the screw hole of the female screw member and fastened to fix the hooked pin, and the outer joint pipe and the inner joint pipe are fitted together. A steel pipe joint structure, characterized in that   The female screw member includes a screw cylinder that stands up around the screw hole, and the screw hole is configured to be threaded so as to continue to the tip of the screw cylinder. The steel pipe joint structure according to claim 1, wherein a counterbore having a depth and a shape for receiving the steel pipe is formed.   The female screw member is configured as an independent member that is independently fixed to the inner peripheral surface of the inner joint pipe for each position of the pin hole of the inner joint pipe, or arranged in the circumferential direction of the pin holes on the inner peripheral surface of the inner joint pipe. The steel pipe according to claim 1 or 2, wherein each of the steel pipes is formed into a ring-shaped member that is fixed along a screw hole. Joint structure.

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