JP2021123934A - Multiple thread screw joint, steel pipe with joint, structure, construction method of structure, and design method and manufacturing method of multiple thread screw joint - Google Patents

Abstract

To provide a multiple thread screw joint capable of eliminating fitting mistakes, and a steel pipe with a joint, a structure, a construction method of the structure, and a design method and a manufacturing method of the multiple thread screw joint.SOLUTION: A multiple thread screw joint 1 of this invention comprises an inner joint pipe 7 having a male thread 5 and an outer joint pipe 13 having a female thread 11 that are attached to an end portion of steel pipes 3, 9. The threads of the inner joint pipe 7 and the outer joint pipe 13 are multiple thread screws with four or more of even-numbered threads, and threads constituting the multiple thread screws satisfy a requirement specified below. The threads comprise two or more kinds of threads, and each kind of thread has even number of threads. All of thread ridges and thread bottoms have the same pitch. All of straight lines and polygons satisfy a requirement specified below: as to a straight line and a polygon formed by connecting positions of neighboring threads of the same kind with each other with a straight line, the straight line passes the center of the pipe and a center of gravity of the polygon accords with the center of the pipe, except a case where all of formed figures are regular polygons.SELECTED DRAWING: Figure 1

Description

The present invention is a multi-threaded joint consisting of an inner joint pipe having four or more even-row male threads and an outer joint pipe having four or more even-row female threads, and a steel pipe with a joint to which the multi-thread joint is attached. The present invention relates to a structure in which a plurality of steel pipes with joints are connected, a method for constructing the structure, and a method for designing and manufacturing a multi-threaded threaded joint.

Structures made of steel pipes used for foundations of structures and prevention of landslides (for example, steel pipe piles, steel pipe sheet piles, steel pipe sheet pile walls connecting steel pipe sheet piles, steel pipe columns, steel pipe beams, etc.) are required depending on the construction conditions. The length may reach several tens of meters. On the other hand, when transporting these steel pipe structures to the construction site, it is not possible to transport long structures due to traffic restrictions. Therefore, they are carried by several meters, which is a length that can be transported, and are joined during construction (including casting) at the construction site.

As a method of joining a structure made of steel pipes at a construction site, a threaded joint as disclosed in Patent Document 1 is used. Screw joints are attached to each end of the steel pipe to be joined, and the steel pipes are joined by rotational fitting at the construction site to construct a structure made of steel pipes.

In the threaded joint disclosed in Patent Document 1, by making the threaded portion a multi-threaded screw, the amount of rotation required for fitting can be reduced, the fitting time can be reduced, and the workability can be improved. In particular, when applying a threaded joint to a steel pipe for a steel pipe sheet pile having a connecting joint that connects adjacent steel pipes, other steel pipe sheet piles within the radius of gyration of the connecting joint may interfere with each other, so it is necessary for fitting. It is effective to reduce the amount of rotation.

Japanese Unexamined Patent Publication No. 10-31028

When applying a threaded joint to a steel pipe for a steel pipe sheet pile, the positions of the connecting joints of the upper steel pipe and the lower steel pipe must be in the same position when the fitting of the upper and lower steel pipes is completed. In this respect, in the case of a multi-thread thread joint, there are as many thread tips as there are threads, and there are as many fitting start positions as there are threads. Therefore, it is necessary to start the fitting from the fitting start position which is the correct position when the fitting is completed. Therefore, the multi-threaded screw joint is provided with an alignment mark at the correct fitting start position, and by starting the fitting in accordance with the alignment mark, the upper and lower connecting joint positions match when the fitting is completed.
Since the same connecting joint is installed on the outer circumference of the steel pipe at intervals of 180 degrees, even if the fitting is started from the position rotated 180 degrees from the position of the alignment mark, the upper and lower joints are connected when the fitting is completed. The joint positions can be matched. That is, in the above case, there are two correct fitting start positions at 180 degree intervals.

However, even if the alignment mark is provided, the mistake of the fitting start position due to human error cannot be completely eliminated, and if the fitting is started from the wrong fitting start position, it goes up and down when the fitting is completed. It can be seen that the connecting joint positions of the above were inconsistent and the fitting start position was incorrect.
In this case, the completed fitting is rotated in the reverse direction again to remove the fitting, the fitting position is adjusted, and the fitting is refitted. It causes a defect.

The present invention has been made to solve such a problem, and has a structure in which a multi-threaded screw joint capable of eliminating a fitting error, a steel pipe with a joint to which the multi-threaded screw joint is attached, and a plurality of steel pipes with the joint are connected. It is an object of the present invention to provide a method of constructing a body and a structure, and a method of designing and manufacturing a multi-threaded threaded joint.

(1) The multi-threaded threaded joint according to the present invention is attached to an end portion of a steel pipe and is composed of an inner joint pipe having a male screw and an outer joint pipe having a female screw. It is a multi-threaded thread joint which is a multi-threaded screw having four or more threads and is characterized in that the threads constituting the multi-threaded screw satisfy the requirements specified below.
(1-1) Two or more types of screws with different shapes shall be provided, and each type of screw shall have an even number of threads.
(1-2) All threads and bottoms shall have the same pitch.
(1-3) A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the pipe. All straight lines and polygons satisfy the condition that they match the center. However, all the formed figures are regular polygons.

(2) Further, in the above-mentioned item (1), all the threads and the thread bottoms are set to have the same joint axial clearance.

(3) Further, in the ones described in (1) or (2) above, the difference in shape is that one or more of the height, width, and angle of the thread and the corresponding screw bottom are different. It is characterized by that.

(4) The steel pipe with a joint according to the present invention is formed by attaching the inner joint pipe and the outer joint pipe in the multi-threaded screw joint according to any one of (1) to (3) above to one end and the other end. It is a feature.

(5) The structure according to the present invention is characterized by including the multi-threaded screw joint according to any one of (1) to (3) above and a plurality of steel pipes connected by the multi-threaded screw joint. Is what you do.

(6) The structure construction method according to the present invention is the structure construction method described in (5) above, in which the rotation of one of the jointed steel pipes to be connected is restricted and the other joint is connected. It is characterized in that the multi-threaded threaded joint of the steel pipe with a joint is aligned with the multi-threaded threaded joint of the steel pipe with one of the joints and is rotationally fitted.

(7) The method for designing a multi-threaded threaded joint according to the present invention comprises an inner joint pipe having a male thread and an outer joint pipe having a female thread attached to the end of a steel pipe, and the inner joint pipe and the outer joint pipe. It is a method of designing a multi-row thread joint in which a screw is a multi-threaded screw having four or more threads, and is characterized in that the threads constituting the multi-threaded screw are designed so as to satisfy the requirements specified below. Is to be.
(7-1) Consists of two or more types of screws with different shapes, and each type of screw has an even number of threads.
(7-2) Set the same pitch for all threads and thread bottoms.
(7-3) A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the pipe. All straight lines and polygons satisfy the condition that they match the center. However, all the formed figures are regular polygons.

(8) The method for manufacturing a multi-threaded threaded joint according to the present invention comprises an inner joint pipe having a male thread and an outer joint pipe having a female thread attached to the end of a steel pipe, and the inner joint pipe and the outer joint pipe. A method for manufacturing a multi-threaded joint in which a screw is an even-row multi-threaded screw having four or more threads, wherein the threads constituting the multi-threaded screw satisfy the requirements specified below. be.
(8-1) Two or more types of screws with different shapes are formed, and each type of screw has an even number of threads.
(8-2) All threads and bottoms shall have the same pitch.
(8-3) A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the pipe. All straight lines and polygons satisfy the condition that they match the center. However, all the formed figures are regular polygons.

In the multi-threaded threaded joint according to the present invention, since it is configured as described above, it cannot be fitted unless the corresponding thread and the thread bottom can be fitted, and misfitting is surely performed. Can be prevented.
Further, since there are two mating positions at 180-degree intervals, when trying to fit from one fitting start position, for example, when the fitting resistance is high due to poor cutting accuracy or the like. The workability is good because the fitting can be performed from the other fitting start position by rotating the fitting 180 degrees.

It is a side view of the state before fitting of the multi-threaded screw joint which concerns on this embodiment. It is a figure which shows the side surface of the state at the time of completion of fitting of the multi-threaded screw joint which concerns on this embodiment through the inside. It is a conceptual diagram of the fitting start position of a male screw and a female screw when the threaded joint of 8 articles which concerns on this embodiment is seen from the upper part. FIG. 4A is an enlarged view showing a part of a state in which the multi-threaded screw joint according to the present embodiment is fitted at a correct position, and FIG. 4A is a fitting state of a screw shape of type A. , FIG. 4B shows a type B screw-shaped fitting state. It is explanatory drawing for demonstrating that the multi-threaded screw joint shown in FIG. 4 cannot be fitted when it tries to fit at an erroneous position. It is explanatory drawing explaining the example which is incompatible with this invention by not satisfying the requirement 1 of this invention. It is explanatory drawing explaining the example that only a straight line is formed when the positions of the same kind of screws are connected by a straight line, FIG. 7A is a conforming example of this invention, and FIG. 7B is a non-conforming example. It is a figure which shows. It is explanatory drawing explaining the example that a straight line and a polygon are formed when the positions of the same kind of screws are connected by a straight line, and is the figure which shows the example which is incompatible with this invention. FIG. 9 (a) is an explanatory diagram (No. 1) for explaining an example in which only a polygon is formed when the positions of screws of the same type are connected by a straight line, and FIG. 9 (a) is a conforming example of the present invention, FIG. 9 (b). ) Is a diagram showing a nonconforming example. It is explanatory drawing (the 2) explaining the example that only a polygon is formed when the positions of the same kind of screws are connected by a straight line, and is the figure which shows the nonconformity example of this invention. It is explanatory drawing explaining the example in which three kinds of screw shapes are formed, and is the figure which shows the conformity example of this invention. It is explanatory drawing explaining the example in which three kinds of screw shapes are formed, and is the figure which shows the nonconformity example of this invention. It is explanatory drawing explaining another aspect 1 of a screw shape, FIG. 13A is the fitting state of the screw shape of type A, and FIG. 13B is the fitting state of the screw shape of type C. be. It is explanatory drawing for demonstrating that the multi-threaded screw joint shown in FIG. 13 cannot be fitted when it tries to fit at an erroneous position. It is explanatory drawing explaining another aspect 2 of a screw shape, FIG. 15A is the fitting state of the screw shape of type A, and FIG. 15B is the fitting state of the screw shape of type D. be. It is explanatory drawing for demonstrating that the multi-threaded screw joint shown in FIG. 15 cannot be fitted when trying to fit at an erroneous position.

As shown in FIGS. 1 and 2, the multi-threaded threaded joint 1 according to the present embodiment is attached to the end of the upper steel pipe 3 and has an inner joint pipe 7 having a male screw 5 and a lower steel pipe 9. The outer joint pipe 13 attached to the end and having the female thread 11 is composed of the outer joint pipe 13, and the threads of the inner joint pipe 7 and the outer joint pipe 13 are the multi-thread joint 1 which is an even-row multi-thread screw having 4 or more threads. , The screw constituting the multi-threaded screw is characterized in that it satisfies the requirements specified below.
Two or more types of screws with different shapes shall be provided, and each type of screw shall have an even number of threads (Requirement 1).
All threads and bottoms must have the same pitch (Requirement 2).
A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon coincides with the center of the pipe. , Satisfy all straight lines and polygons. However, all the formed figures are regular polygons (Requirement 3).
1 and 2 are examples of a multi-threaded threaded joint 1 satisfying the above requirements. Each configuration of the multi-threaded screw joint 1 will be described in detail below.

<Steel pipe>
The steel pipes 3 and 9 constitute piles, and the upper steel pipe 3 in the drawing constitutes an upper pile and the lower steel pipe 9 constitutes a lower pile.
In the present embodiment, the inner joint pipe 7 having the male screw 5 is fixed to the upper steel pipe 3 by welding, and the outer joint pipe 13 having the female screw 11 is fixed to the lower steel pipe 9 by welding.
However, the inner joint pipe 7 may be fixed to the lower steel pipe 9, and the outer joint pipe 13 may be fixed to the upper steel pipe 3.

<Inner fitting pipe, outer fitting pipe>
The inner joint pipe 7 is formed with a male screw 5 composed of four or more even-numbered multi-threaded threads. Further, the outer joint pipe 13 is formed with a female screw 11 composed of even-numbered multi-threaded threads having the same number of threads as the inner joint pipe 7.
The multi-threaded threads included in the inner joint pipe 7 and the outer joint pipe 13 include threads 5a and 11a and corresponding screw bottoms 11b and 5b (type A), and threads 5as and 11as and corresponding screws. It has two types of screws with different shapes at the bottom 11bs and 5bs (type B) (parts shown by diagonal lines), and the type A and type B screws are each formed with an even number of threads (requirement 1). .. Note that FIG. 1 is a side view of the multi-threaded screw joint 1, and even in the male screw 5 and the female screw 11, only the portion that can be seen from one side surface is shown.
In addition, all threads and thread bottoms are set to have the same pitch (Requirement 2).

Further, a specific example will be described in detail with reference to FIG. 3, but the type A screw and the type B screw are formed so as to satisfy the above-mentioned requirement 3, respectively, and the examples shown in FIGS. 1 and 2 are shown. Satisfies all of requirements 1 to 3 which are the requirements of the present invention.

In the multi-threaded threaded joint 1 of the present embodiment configured as described above, if the fitting start positions of the screws having the same shape in the inner joint pipe 7 and the outer joint pipe 13 do not match, rotary fitting is performed. Can't. In other words, as shown in FIG. 2, rotary fitting can be performed only when the fitting start positions of screws having the same shape match. Specifically, according to the present embodiment, since there are two positions where the fitting start positions of the screws having the same shape match at intervals of 180 degrees, rotary fitting is possible only at these two positions. ..
This point will be specifically described by taking the 8-thread screw shown in FIG. 3 as an example.

FIG. 3 is a conceptual diagram of the screw start positions of the male screw 5 and the female screw 11 when the threaded joint of 8 threads is viewed from above. FIG. 3A shows one type of screw shape as in the conventional example, and the male screw 5 and the female screw 11 can start fitting if the positions of the black circles match. That is, fitting is possible at eight positions, which is the same as the number of threads.

On the other hand, FIGS. 3 (b) to 3 (d) show an example of the present invention. Similar to FIGS. 1 and 2, it has two types of screw shapes, type A and type B, which have different shapes, and six types of A and two types of B are formed, satisfying requirement 1. In the figure, a black circle is attached to the fitting start position of the type A screw, and a star mark is attached to the fitting start position of the type B screw. The cross in the center indicates the center 15 of the tube.
Furthermore, adjacent objects of the same type are connected by a straight line (the straight line connecting the black circles is indicated by a solid line, and the straight line connecting the stars is indicated by a broken line), and when a polygon is formed by the straight line, its center of gravity is determined. Shown in the figure (polygon center of gravity 17). 6 to 12 which will be described later are also illustrated in the same manner.

In FIGS. 3 (b) to 3 (d), the center of gravity 17 of the polygon formed by connecting the black circles (type A) coincides with the center 15 of the pipe, and the stars (type B) are connected. Since the straight line formed by is passing through the center 15 of the pipe, it satisfies the requirement 3. The arrows attached to the male screw 5 and the female screw 11 indicate the alignment mark.

FIG. 3B shows a state of the correct fitting start position where the alignment marks of the male screw 5 and the female screw 11 match, and the screw shapes facing each other in all the threads match, and the fitting can be started.

FIG. 3 (c) shows a state in which the female screw 11 is rotated clockwise by 45 degrees from the state of FIG. 3 (b). In the state shown in FIG. 3C, the screw shapes of 4 of the 8 screws do not match. As described above, when the different shapes of any of the screws are opposed to each other, the fitting cannot be started. The reason why the mating cannot be started will be described later.

FIG. 3D shows a state in which the female screw 11 is further rotated clockwise and rotated 180 degrees from the state shown in FIG. 3B. In the state shown in FIG. 3 (d), the alignment marks of the male screw 5 and the female screw 11 are displaced by 180 degrees, but since the screw shapes of the male screw 5 and the female screw 11 match in all the threads, FIG. 3 (b) The fitting can be started in the same manner as in the above.

Below, as shown in FIGS. 3 (b) and 3 (d), two types of screws having different shapes shown below are shown for the state when the screws having the same shape are fitted at the same fitting start position. Let's take an example.
FIG. 4 shows, as an example of two types of screws having different shapes, screw threads 5a and 11a and corresponding screw bottoms 11b and 5b (type A), and thread 5as and 11as and corresponding screw bottoms 11bs. The heights of 5bs (type B) are different.
FIG. 4A shows a state in which the threads 5a and 11a of the type A and the thread bottoms 11b and 5b are properly fitted. As an example, the height of the thread 11a of the female screw 11 that is properly fitted is high. The diameter h is 4.0 mm, and the radial clearance c ₁ between the male screw 5 and the screw bottom 5b is 0.5 mm.
Further, FIG. 4B shows a state in which the type B threads 5as and 11as and the thread bottoms 11b and 5bs are properly fitted. As an example, the height H of the thread 11as of the female thread 11 is 2.0. _{In mm, the clearance C 1} between the male screw 5 and the screw bottom 5 bs is 0.5 mm.

The screw pitch P is 10 mm for both the type A screw shape and the type B screw shape. The screw pitch P is the axial distance from the end of the screw bottom of the male screw 5 in one thread to the starting position of the screw bottom of the next male screw 5 in one thread, or from the end of the thread of the female thread 11 in one thread. This is the axial distance to the starting position of the next thread.
In the case of a single-threaded screw, the screw pitch means the distance traveled by the screw when it makes one rotation, but in the case of a multi-threaded screw, the distance traveled when it makes one rotation differs depending on the number of threads of the screw, so it is constant. Since the screw pitch as the distance cannot be defined, it is defined as above.

As shown in FIGS. 4A and 4B, if the threads of the male thread 5 and the female thread 11 correspond to each other in the same type, the fitting can be started, and the inner joint having the male thread 5 can be started. The outer joint pipe 13 having the pipe 7 and the female screw 11 can be rotationally fitted.

Next, as shown in FIG. 3C, a state in which the fitting start positions of screws having different shapes cannot start fitting with respect to each other will be described with reference to FIG.

FIG. 5 shows a state when the type A and type B screws shown in FIG. 4 are about to be fitted. When screws with different thread and thread bottom heights, such as type A and type B, try to fit, as shown in FIG. 5, 2.5 mm including _{the clearance C 1 of the male screw 5 of type B.} At the screw bottom 5 bs (H + C ₁ ), a thread 11 a having a screw height h of 4.0 mm, which is a female screw 11 of type A, is located, and cannot start fitting due to interference.

As described above, if either the male screw 5 and the female screw 11 are opposed to different types of screws, the fitting cannot be started, and the inner joint pipe 7 having the male screw 5 and the outer joint having the female screw 11 cannot be started. The tube 13 cannot be rotationally fitted.

In order to prevent the type A screw and the type B screw from fitting, the difference in thread height must be a _{clearance c 1 or more.} For example, type B thread 5as, height H of type B, type B thread bottom 5bs, 11bs and thread 11as, 5as clearance C ₁ , type A thread 5a, 11a height h, type A. The relationship between the screw bottoms 5b and 11b and the clearance c ₁ of the threads 11a and 5a is h> H + C ₁ or H> h + c ₁ .

As described above, using an example of the multi-threaded threaded joint 1 satisfying the requirements 1 to 3, the configuration of the multi-threaded threaded joint 1 and the multi-threaded threaded joint 1 are rotated 180 degrees from the correct fitting start position and the correct fitting start position. It has been explained that the fitting is possible only at the two positions where the fitting is performed.
Next, the reason why each requirement is required will be described in detail for each requirement.

<Requirement 1>
The reason why Requirement 1 "equipped with two or more types of screws having different shapes and each type of screw has an even number of threads" is as follows.
First, two or more types of screws having different shapes are provided in order to prevent screws having different shapes from facing each other and starting fitting at an incorrect fitting start position, as described with reference to FIG. The fact that screws having different shapes cannot be fitted is as described in FIGS. 4 and 5, and the description thereof will be omitted.

Further, the reason why each type of screw has an even number of threads is that it enables fitting at a position rotated 180 degrees from the correct fitting start position. This point will be described with reference to FIG.
The example shown in FIG. 6 does not satisfy the condition that "each type of screw has an even number of threads" and is not suitable for the present invention. In the figure, only the male screw 5 is shown, and the female screw 11 having the same shape is omitted (hereinafter, the same applies to FIGS. 7 to 12). This example is a 6-thread screw having two types of screw shapes, type A (black circle mark) and type B (star mark), and both types A and B are formed with three threads each. All threads and thread bottoms have the same pitch (Requirement 2, hereinafter the same applies to FIGS. 7 to 12 and the description is omitted), and a triangle formed by connecting black circles and stars with straight lines. The center of gravity of (the center of gravity of the polygon 17) coincides with the center 15 of the pipe (Requirement 3).

In the example shown in FIG. 6, neither the black circle mark nor the star mark is 180 degrees symmetrical, so that the shapes of the opposing screws do not match when rotated 180 degrees, and the screws cannot be fitted.
Not limited to this example, if the number of threads of the same type of screw is odd, it cannot be arranged 180 degrees symmetrically, so that each type of screw needs to have an even number of threads.
Further, if each type of screw has an even number of threads, the total number of threads of the multi-threaded screw is inevitably 4 or more even numbered threads. It is applicable.

<Requirement 2>
Next, the reason why requirement 2 "all threads and thread bottoms have the same pitch" is required is as follows.
The "pitch" in the present embodiment is the "screw pitch P" described with reference to FIG. 4, and as described above, the "screw pitch P" is the following from the end of the screw bottom of the male screw 5 in a certain row. The axial distance to the starting position of the screw bottom of the one male screw 5 or the axial distance from the end of the thread of one female screw 11 to the starting position of the next one thread.
The fact that such pitches are the same is a condition necessary for the male and female threads of the multi-threaded screw to be fitted, and is a requirement generally required for the multi-threaded screw, and thus the description thereof will be omitted.

<Requirement 3>
Next, Requirement 3 "A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the pipe. Explain why all straight lines and polygons satisfy the condition that they match the center of the above, except that all the formed figures are regular polygons.
Like Requirement 1, Requirement 3 is a requirement for enabling fitting at a position rotated 180 degrees from the correct fitting start position. This will be explained by dividing the formed figures into three patterns: (i) straight lines only, (ii) straight lines and polygons, and (iii) polygons only, and exemplifying those that meet requirement 3 and those that do not. do. All of the examples shown below satisfy Requirement 1 and Requirement 2.

≪ (i) Straight line only≫
First, FIG. 7 shows an example in which only a straight line is formed, that is, an example in which two screws of each type are formed. Both FIGS. 7 (a) and 7 (b) are four-threaded screws in which two types of screws, type A (black circle) and type B (star), are formed.
FIG. 7A shows that all straight lines pass through the center 15 of the pipe and satisfy the requirement 3. In the four-threaded screw, there are four places where the screw positions match, the rotation angles are 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Among them, in the example shown in FIG. 7 (a), all the threads The screw shapes match only at two points, 0 degrees and 180 degrees. This is because when the straight line connecting the two rows passes through the center 15 of the pipe, the two rows are in a 180-degree symmetric relationship.
As shown in FIG. 7A, if all types of straight lines pass through the center 15 of the pipe, that is, all types have the property of 180 degree symmetry, so that all types of straight lines have a shape when rotated 180 degrees. Are matched and mating is possible.

On the other hand, in FIG. 7B, none of the straight lines pass through the center 15 of the pipe and does not satisfy the requirement 3. Therefore, none of the types is 180-degree symmetric, and the fitting position is only one of the correct fitting start positions, which is not suitable for the present invention.

≪ (ii) Straight lines and polygons≫
Next, an example in which a straight line and a polygon are formed will be described. The examples shown in FIGS. 3 (b) to 3 (d) are examples thereof, and will be described with reference to FIG.
3 (b) to 3 (d) are 8-threaded screws in which 6 type A screws and 2 type B screws are formed as described above. The hexagonal center of gravity (polygonal center of gravity 17) formed by connecting the black circles (type A) with a straight line coincides with the center 15 of the pipe. Further, the straight line connecting the stars (type B) passes through the center 15 of the pipe, and FIGS. 3 (b) to 3 (d) satisfy the requirement 3.

As described above, since the straight line connecting the two rows of the type B passes through the center 15 of the pipe, the two rows of the type B have a 180-degree symmetric relationship.
In addition, since a figure that is 180-degree symmetric has the property that its symmetry point (center of rotation) coincides with the center of gravity, a hexagon formed by connecting black circles (type A) with a straight line is also 180-degree symmetric. It can be said to be a figure. Therefore, in the examples shown in FIGS. 3 (b) to 3 (d), since both types A and B have the property of 180 degree symmetry, the screw shapes match in all the stripes when rotated 180 degrees, and the threads are fitted. Is possible.

FIG. 8 shows an example of a non-conforming product in the case where a straight line and a polygon are formed.
In the example shown in FIG. 8, similarly to FIGS. 3 (b) to 3 (d), there are 6 threads of type A and 2 threads of type B, but all of them have straight lines. It does not pass through the center 15 of the pipe, and the center of gravity 17 of the polygon does not coincide with the center 15 of the pipe. Therefore, none of the types has a 180-degree symmetric relationship, and the fitting position is only one of the correct fitting start positions, which is not suitable for the present invention.

≪ (iii) Polygon only≫
Next, an example in which only a polygon is formed is shown in FIGS. 9 and 10.
Each of the examples shown in FIGS. 9 and 10 is an 8-thread screw in which two types of screws of type A (black circle mark) and type B (star mark) are formed in four threads each.
In FIG. 9A, the center of gravity (center of gravity 17 of the polygon) of both the solid line rectangle (type A) and the broken line rectangle (type B) coincides with the center 15 of the pipe and satisfies the requirement 3. be.
As described above, since both types A and B have a property of 180 degree symmetry, the shapes of all the strips match when rotated 180 degrees, and fitting is possible.

On the other hand, in FIG. 9B, similarly to FIG. 9A, the center of gravity (center of gravity 17 of the polygon) of both the solid square (type A) and the broken line square (type B) is the center 15 of the tube. Although they match, this is an example incompatible with the present invention because it corresponds to "all the formed figures are regular polygons".

Next, in Requirement 3, the reason for "excluding those in which all the formed figures are regular polygons" will be described below.
The example shown in FIG. 9B has a property of 180 degree symmetry, but further, the screw shape is the same in all the stripes even when rotated by 90 degrees or 270 degrees. That is, there are four rotation positions that can be fitted out of 360 degrees, and the object of the present invention that allows fitting only at two positions, the correct fitting start position and the position rotated by 180 degrees, is not achieved. This applies not only to squares but also to other regular polygons.
However, among the screw shapes of the screws constituting the multi-threaded screw, if the figure formed by connecting the straight lines includes at least one type of polygon that is not a straight line or a regular polygon, the requirement 3 can be satisfied.

FIG. 10 shows another example of what is incompatible with the present invention when only polygons are formed.
The examples shown in FIG. 10 are 8-threaded screws in which 4 types of A screws and 4 types of B-threads are formed, as in FIG. 9, but two quadrangular centers of gravity (polygonal centers of gravity) are formed. 17) neither coincides with the center 15 of the tube. Therefore, both types A and B do not have the property of 180 degree symmetry, and the fitting position is only one correct fitting start position, which is not suitable for the present invention.

As described above, the multi-threaded screw joint 1 in the present embodiment can start fitting only at two places at 180 degree intervals, and cannot start fitting from positions other than these two places. .. Therefore, if the alignment mark is attached as shown in FIG. 3 (b), the rotary fitting can be performed at the correct fitting start position, and if a human error occurs, the alignment is performed as shown in FIG. 3 (c). If you make a mistake, you cannot start mating. Therefore, it is immediately known that the fitting start position is incorrect, and the construction efficiency can be improved as compared with the case where the rotary fitting is redone due to the incorrect fitting.

Furthermore, since there are two mating positions at 180-degree intervals, even if a connecting joint is provided like a steel pipe for a steel pipe sheet pile, mating can be started from either of the two locations. Workability is good because the positions of the connecting joints of the upper and lower steel pipes match.

In the above description, the multi-threaded screw joint 1 having two types of screw shapes has been described as an example, but the present invention is not limited thereto. As long as it satisfies each of the above requirements, it may have three or more types of screw shapes, and may be, for example, the one shown in FIG.

FIG. 11A shows an 8-thread screw in which 4 types of A (black circle) screws, 2 types of B (star) screws, and 2 types of C (square) screws are formed. The center of gravity of the quadrangle (center of gravity of the polygon 17) formed by connecting the black circles (type A) with a straight line coincides with the center 15 of the pipe. A straight line connecting the star mark (type B) and the square mark (type C) passes through the center 15 of the pipe.

FIG. 11B shows a 12-threaded screw in which 6 types of A (black circle) screws, 4 types of B (star) screws, and 2 types of C (square) screws are formed. A hexagonal center of gravity (polygonal center of gravity 17) formed by connecting black circles (type A) with a straight line and a quadrangular center of gravity (polygonal center of gravity 17) formed by connecting star marks (type B) with a straight line. Both coincide with the center 15 of the tube. A straight line connecting the square marks (type C) passes through the center 15 of the pipe.
As described above, both FIGS. 11 (a) and 11 (b) are conforming examples satisfying the requirements of the present invention, and even when rotated 180 degrees, all the strips can be fitted in the same shape. be.

On the other hand, the example shown in FIG. 12 corresponds to "all the formed figures are regular polygons" because all the formed figures are squares, and is not suitable for the present invention. FIG. 12 shows that there are four rotation positions that can be fitted as in FIG. 9B, and the object of the present invention is that fitting can be performed only at two positions, the correct fitting start position and the position rotated by 180 degrees. Do not achieve.

In addition, also in the two examples shown in FIG. 11, the formed figure includes a square like the black circle mark in FIG. 11 (a) and the star mark in FIG. 11 (b), but it is formed in other types. Since the figure is a polygon that is not a straight line or a regular polygon, it does not correspond to the above-mentioned "all the formed figures are regular polygons" and satisfies the requirement 3.

In the description of FIGS. 4 and 5, different types of screw shapes are formed by setting the height of the screw thread and the corresponding screw bottom so as to be different from the others. Is not limited to this, in short, it suffices to form a screw shape that cannot be fitted with other screws, and a mode for making the screw shape different from other screw shapes is, for example, another mode 1 described below. 2nd grade can be mentioned.

<Other aspect 1>
In another aspect 1, the type C threads 5ass and 11ass and the corresponding thread bottoms 11bs and 5bss have the same thread pitch as the type A threads 5a and 11a and the thread bottoms 11b and 5b, and the threads are screwed. The widths are different. This will be described with reference to FIGS. 13 and 14.
FIG. 13A shows the type A threads 5a and 11a and the thread bottoms 11b and 5b, and is in a state of being properly fitted. As an example, the thread width w of the appropriately fitted female thread 11 is 3.4 mm, and the axial clearance c ₂ between the male thread 5 and the thread bottom 5b is 0.5 mm.
Further, FIG. 13B shows the thread threads 5ass and 11ass and the thread bottom 11bss and 5bss of the type C, and is in a state of being properly fitted. As an example, the screw width W of the female screw 11 of this type C is 2.4 mm, and the axial clearance C ₂ between the male screw 5 and the screw bottom 5 bs is 0.7 mm.
The screw pitch P is 10 mm for both types A and C.

As shown in FIG. 13B, the corresponding threads 5ass and 11ass of type C and the thread bottoms 11bss and 5bss can be fitted to each other, and have an inner joint pipe 7 having a male thread 5 and a female thread 11. The outer joint pipe 13 can be fitted.
However, when the type A screw and the type C screw try to fit together, as shown in FIG. 14, the screw bottom 5 bss of 3.1 mm (W + C _{2 ) including the clearance C 2 of the male screw 5 of the type C} However, a thread 11a having a screw width w of 3.4 mm, which is a female screw 11 of type A, is located there, and the inner joint pipe 7 and the outer joint pipe 13 cannot be started to be fitted due to interference.

In order to prevent different types of screws from being fitted, the difference in thread width must be a _{clearance of c 2 or more.} For example, type C thread 5ass, 11ass width W, type C thread bottom 11bss, 5bs and thread 5ass, 11ass clearance C ₂ , type A thread 5a, 11a width w, type A thread bottom. The relationship between 11b and 5b and the clearance c ₂ of the threads 5a and 11a is w> W + C ₂ or W> w + c ₂ .

<Other aspect 2>
In another aspect 2, the type D threads 5asss and 11asss and the corresponding thread bottoms 11bss and 5bss have the same pitch as the type A threads 5a and 11a and the thread bottoms 11b and 5b, and the screw angles. Is different. This will be described with reference to FIGS. 15 and 16. Note that the different screw angles mean that both the cases where the flank angles on both sides of the thread are different and the cases where the flank angles on one side are different are included.

FIG. 15A shows the type A threads 5a and 11a and the thread bottoms 11b and 5b, and is in a state of being properly fitted. As an example, the lower flank angle α in the figure of the thread 11a of the female screw 11 and the screw bottom 5b of the male screw 5 that are properly fitted is set to about 10 °. As a result, the screw width w of the female screw 11 is 3.4 mm, and the axial clearance c ₂ between the male screw 5 and the screw bottom 5b is 0.5 mm.

Further, FIG. 15B shows the type D threads 5asss and 11asss and the screw bottoms 11bss and 5bss, and is in a state of being properly fitted. As an example, the lower flank angle β in the figure of the thread 11 asss of the female thread 11 of this type D and the thread bottom 5 bsss of the male thread 5 is about 20 °. As a result, the screw width W of the female screw 11 is 2.2 mm, and the axial clearance C ₂ between the male screw 5 and the screw bottom 5 bs is 0.6 mm.
The screw pitch P is 10 mm for both types A and D.

As shown in FIG. 15B, the corresponding threads 5ass and 11asss of type D and the thread bottoms 11bss and 5bss can be fitted to each other, and have an inner joint pipe 7 having a male thread 5 and a female thread 11. The outer joint pipe 13 can be fitted.
However, when the type A screw and the type D screw try to fit together, as shown in FIG. 16, when the thread 11a of the type A female screw 11 is located at the thread bottom 5 bsss of the type D male screw 5. Due to the difference in flank angle, they cannot be fitted because they interfere with each other, and the inner joint pipe 7 and the outer joint pipe 13 cannot be fitted.

Also in the present invention, it is better to have a guideline for starting fitting, and it is preferable to provide an alignment mark. Even if the alignment mark is provided, misfitting may occur due to a human error, but by applying the present invention, such a human error can be reliably prevented.
Further, since the change in the screw shape in the present invention can be manufactured by changing the cutting blade and the cutting program without significantly increasing the conventional cutting process, the present invention prevents misfitting of the screw at low cost. It can be said that it can be done.

In the above example, parallel threads (threads whose threads are on the outer or inner surface of a cylinder) are targeted, but tapered threads (threads whose threads are on the outer or inner surface of a cone) can also be applied. , It is possible to prevent erroneous fitting even with a tapered screw without any problem.
If the fitting position on the outer joint pipe 13 side cannot be confirmed without looking into the front side from the upper part with a large diameter, the thread of the outer joint pipe 13 can be made different from the others so that it can be visually checked from the upper side. It becomes easy to determine the fitting position.

In the other form 1 described above, the type C thread and the corresponding thread bottom axial clearance (gap) C ₂ are 0.7 mm, and the type A thread and the corresponding thread bottom joint. An example in which the axial gap c ₂ is 0.5 mm is shown, and in another form 2, the thread of type D and the corresponding axial clearance (gap) C _{2 of} the screw bottom are 0.6 mm, and the type A is used. joint axial clearance c ₂ ridge and the bottom corresponding thereto of the showed example of 0.5 mm.
However, the multi-threaded threaded joint of the present invention is attached to the end of a steel pipe constituting the structure, and when a load is applied, all the threads are evenly contacted in the axial direction to transmit the load. Is more preferable.
Therefore, the type C and type D threads and the corresponding thread bottom axial clearance (gap) C ₂ and the type A thread and the corresponding thread bottom joint axial clearance c ₂ are the same. More preferably. Similarly, when one multi-thread screw has three or more different screw shapes, it is preferable that the joint axial clearances of all the threads and the screw bottoms are set to be the same.

Further, in the above embodiment, the multi-row screw joint to be attached to the end of the steel pipe has been described, but this multi-row screw joint constitutes a steel pipe pile, a steel pipe sheet pile, a steel pipe column, a steel pipe beam, etc. in advance at a factory or the like. A steel pipe with a joint can be constructed by attaching it to the end of the steel pipe by welding or the like.
In the above embodiment, the steel pipe has been described as having a cylindrical shape having a circular cross-sectional shape orthogonal to the pipe axis direction, but the present invention is not limited to this. For example, a square steel pipe having a rectangular cross-sectional shape orthogonal to the pipe axis direction is also included in the steel pipe of the present invention.

Then, at a construction site or the like, by connecting a plurality of multi-row threaded joints of steel pipes with joints, structures such as steel pipe piles, steel pipe sheet piles, steel pipe sheet pile walls connecting steel pipe sheet piles, steel pipe columns, and steel pipe beams are formed. be able to. That is, these structures include a multi-threaded threaded joint described in the above embodiment and a plurality of steel pipes connected by these multi-threaded threaded joints.
When forming these structures, the multi-threaded threaded joint of the other steel pipe with a joint is aligned with the multi-threaded threaded joint of the one steel pipe with a joint while restraining the rotation of one of the steel pipes with a joint to be connected. Then, it may be rotationally fitted.
For example, when the structure is a steel pipe pile or a steel pipe sheet pile, one steel pipe with a joint may be driven into the ground first, the other steel pipe with a joint may be joined, and then the casting may be repeated.
For example, when the structure is a steel pipe sheet pile wall, a steel pipe with a joint having one connecting joint is first hit into the ground while being connected by a connecting joint next to another steel pipe with a joint that is already in the ground. It may be installed, the other steel pipe with a joint is joined, the positions of the connecting joints are aligned, and then the casting is repeated.
At this time, the method of placing the steel pipe with a joint in the ground is not particularly limited, and any of the Nakadori pile method, the steel pipe soil cement pile method, the rotary pile method, the vibration method, the striking method and the like can be applied.

Since the multi-threaded screw joint of the present invention can reliably prevent misfitting, the connecting joint positions of the upper and lower steel pipe sheet piles do not differ when the rotary fitting is completed as in the case of steel pipe sheet piles, and the rotary fitting can be performed. There is no need to redo, and construction efficiency is improved.

Further, in the above description, the multi-threaded threaded joint has been described as an invention of the product, but the multi-threaded threaded joint is designed by the following design method.
It is attached to the end of a steel pipe and consists of an inner joint pipe having a male thread and an outer joint pipe having a female thread. It is a design method for threaded joints.
The screws constituting the multi-thread screw are designed to meet the requirements specified below.
Consists of two or more types of screws with different shapes, and each type of screw has an even number of threads (corresponding to Requirement 4 and Requirement 1 above).
All threads and bottoms should have the same pitch (corresponding to Requirement 5 and Requirement 2 above).
A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon coincides with the center of the pipe. , Satisfy all straight lines and polygons. However, all the formed figures are regular polygons (requires 6 and 3 above).

Further, the multi-threaded screw joint described as the invention of the product is manufactured by the following manufacturing method.
It is attached to the end of a steel pipe and consists of an inner joint pipe having a male thread and an outer joint pipe having a female thread. It is a manufacturing method of threaded joints.
The screws constituting the multi-threaded screw satisfy the requirements specified below.
Two or more types of screws with different shapes are formed, and each type of screw has an even number of threads (requires 7 and 1 above).
All threads and bottoms should have the same pitch (corresponding to Requirement 8 and Requirement 2 above).
A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon coincides with the center of the pipe. , Satisfy all straight lines and polygons. However, all the formed figures are regular polygons (requires 9 and 3 above).

1 Multi-thread thread joint 3 Upper steel pipe 5 Male thread 5a Thread (type A)
5b Thread bottom (type A)
5as thread (type B)
5bs screw bottom (type B)
5ass thread (type C)
5bss screw bottom (type C)
5asss thread (type D)
5bss screw bottom (type D)
7 Inner joint pipe 9 Lower steel pipe 11 Female thread 11a Thread (type A)
11b Thread bottom (type A)
11as thread (type B)
11bs screw bottom (type B)
11ass thread (type C)
11bss screw bottom (type C)
11asss thread (type D)
11bss screw bottom (type D)
13 Outer joint pipe 15 Center of pipe 17 Polygonal center of gravity

Claims (8)

It is attached to the end of a steel pipe and consists of an inner joint pipe having a male thread and an outer joint pipe having a female thread. It is a threaded joint
A multi-threaded threaded joint characterized in that the threads constituting the multi-threaded screw satisfy the requirements specified below.
(1) Two or more types of screws with different shapes shall be provided, and each type of screw shall have an even number of threads.
(2) All threads and bottoms must have the same pitch.
(3) A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the center of the pipe. All straight lines and polygons satisfy the condition of matching. However, all the formed figures are regular polygons. The multi-threaded threaded joint according to claim 1, wherein the joint axial clearance between all the threads and the threaded bottom is set to be the same. The multi-threaded threaded joint according to claim 1 or 2, wherein the difference in shape is that one or more of the height, width, and angle of the thread and the corresponding thread bottom are different. A steel pipe with a joint, wherein the inner joint pipe and the outer joint pipe in the multi-threaded screw joint according to any one of claims 1 to 3 are attached to one end and the other end. A structure comprising the multi-threaded screw joint according to any one of claims 1 to 3 and a plurality of steel pipes connected by the multi-threaded screw joint. The method for constructing a structure according to claim 5, wherein the multi-threaded threaded joint of the steel pipe with a joint to be connected is connected to the steel pipe with a joint of the other while restraining the rotation of one of the steel pipes with a joint to be connected. A method of constructing a structure, which is characterized in that it is aligned with a multi-threaded threaded joint and rotationally fitted. It is attached to the end of a steel pipe and consists of an inner joint pipe having a male thread and an outer joint pipe having a female thread. It is a design method for threaded joints.
A method for designing a multi-threaded thread joint, characterized in that the threads constituting the multi-threaded screw are designed so as to satisfy the requirements specified below.
(4) Consists of two or more types of screws with different shapes, and each type of screw has an even number of threads.
(5) Set the same pitch for all threads and thread bottoms.
(6) A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the center of the pipe. All straight lines and polygons satisfy the condition of matching. However, all the formed figures are regular polygons. It is attached to the end of a steel pipe and consists of an inner joint pipe having a male thread and an outer joint pipe having a female thread. It is a manufacturing method of threaded joints.
A method for manufacturing a multi-threaded screw joint, wherein the threads constituting the multi-threaded screw satisfy the requirements specified below.
(7) Two or more types of screws with different shapes are formed, and each type of screw has an even number of threads.
(8) All threads and bottoms should have the same pitch.
(9) A straight line or polygon formed by connecting the positions of adjacent screws of the same type with a straight line, the straight line passes through the center of the pipe, and the center of gravity of the polygon is the center of the pipe. All straight lines and polygons satisfy the condition of matching. However, all the formed figures are regular polygons.

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