JP2017089818A - Method and structure for joining different diameter steel pipes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection method and connection structure capable of connecting steel pipes with different diameters to each other with a relatively simple structure and step.SOLUTION: A large-diameter steel pipe 21 including an inside plate 23 and a small-diameter steel pipe 11 including an outside plate 13 are fixed by a bolt 42 and a nut 41. At that time, in a temporal fixing step, the nut 41 is temporarily screwed into a shaft part 44 of the bolt 42 projecting to the outside of the inside plate 23. Next, from a pipe inner side of the inside plate 23, a head part 43 of the bolt 42 is supported by a support member 42. Then, the nut 41 is released from temporal fixation, the shaft part 44 of the bolt 42 is inserted into a bolt insertion hole 14 of the outside plate 13, and the nut 41 is screwed to perform final fixation.SELECTED DRAWING: Figure 1

Description

The present invention relates to a joining method and a joining structure in which two steel pipes having different outer diameters, a large diameter steel pipe and a small diameter steel pipe, are connected in the axial direction.

About this kind of joining method and joining structure, what is shown to patent documents 1-3 is known. These Patent Documents 1 to 3 are two steel pipes having different outer diameters of a large-diameter steel pipe and a small-diameter steel pipe, and the large-diameter steel pipe includes an inner plate projecting inside a large-diameter connection end, and the small-diameter steel pipe The steel pipe includes an outer plate projecting outside a small-diameter connection end, the inner plate and the outer plate have bolt insertion holes at positions where they match each other, and the inner plate and the outer plate are inserted into the bolt insertion hole. The method and structure which join the said large diameter steel pipe and the said small diameter steel pipe to an axial direction by fixing with the volt | bolt and nut which were passed by the hole are shown.

This type of connection structure is often a work at a high place, such as connecting a small diameter steel pipe on site construction on a large diameter steel pipe that has been erected, such as an advertising pillar, It is important to realize safe work with a relatively simple structure and process.

Although Patent Documents 1 and 2 have a relatively simple structure and process, there is still room for improvement, and the connection structure of Patent Document 3 has a relatively complicated structure.
Further, in any of Patent Documents 1 to 3, the large diameter steel pipe and the small diameter steel pipe are connected and fixed by bolts and nuts, but the nuts are only used for final tightening.

Japanese Patent No. 3307203 Japanese Patent No. 5660803 Japanese Patent No. 4301973

This invention makes it a subject to provide the joining method of different diameter steel pipes and the joining structure which implement | achieve joining of different diameter steel pipes by a comparatively simple structure and process.
Especially in this invention, this invention makes it a subject to provide the joining method and joining structure of different diameter steel pipes which can perform rotation prevention of a volt | bolt more reliably.
In addition, the present invention does not use the nut only for final tightening, but also effectively uses the nut in the joining process of the different diameter steel pipes, thereby reducing the joining process of the different diameter steel pipes and the number of parts. It is an object of the present invention to provide a bonding method and a bonding structure that can be realized.

In the joining structure of different diameter steel pipes according to the present invention, a large diameter steel pipe and a small diameter steel pipe having different outer diameters are joined in the axial direction by providing the following structure.
That is, in the joining structure of different diameter steel pipes according to the present invention, the shaft portion of the bolt protrudes from the bolt insertion hole of the outer plate and is screwed with the nut, and the head of the bolt The portion is located inside the pipe of the large-diameter steel pipe of the inner plate, and is in contact with a support member fixed to the inside of the pipe of the large-diameter steel pipe of the inner plate.
Since the head of the bolt is in contact with the support member, the bolt head is prevented from turning.
In particular, it is preferable that the support member includes a rotation-preventing portion that prevents the bolt from rotating around the head portion, and the support member is fixed to the inner plate by a male screw. The head of the male screw is preferably located between the inner plate and the outer plate.

Although the joining method of the different diameter steel pipes which concern on this invention can be implemented by various specific methods, what provided the following process can be shown as the example.
(A) A step of providing an inner plate projecting inside the large-diameter connection end on the large-diameter steel pipe.
(B) A step of providing an outer plate projecting outside the small diameter connection end on the small diameter steel pipe.
(C) A step of passing a bolt having a head from the inner side of the inner plate of the large-diameter steel pipe to the outer side of the pipe through the bolt insertion hole of the inner plate by work from the work opening of the inner plate.
(D) A step of temporarily fixing the nut by screwing onto a shaft portion of the bolt protruding outward from the inner plate by an operation from the outer side of the tube of the inner plate.
(E1) A step of supporting the head of the bolt from the inside of the tube with a support member.
(F1) The step of removing the temporary fixing of the nut and passing the shaft portion of the bolt protruding outside the pipe of the inner plate through the bolt insertion hole of the outer plate to match the inner plate and the outer plate.
(G) A step of screwing a nut into a shaft portion of a bolt protruding from the outer plate and fixing the nut.

In addition, as an example which does not perform temporary fixing with a nut, what was provided with the following process can be shown.
(A) A step of providing an inner plate projecting inside the large-diameter connection end on the large-diameter steel pipe.
(B) A step of providing an outer plate projecting outside the small diameter connection end on the small diameter steel pipe.
(C) A step of passing a bolt having a head from the inner side of the inner plate of the large-diameter steel pipe to the outer side of the pipe through the bolt insertion hole of the inner plate by work from the work opening of the inner plate.
(E2) A step of supporting the head portion of the bolt from the inside of the tube by the support member while holding the shaft portion of the bolt on the outside of the tube.
(F2) A step of passing the shaft portion of the bolt protruding outside the pipe of the inner plate through the bolt insertion hole of the outer plate to match the inner plate and the outer plate.
(G) A step of screwing a nut into a shaft portion of a bolt protruding from the outer plate and fixing the nut.

In addition, as a result of diligent research to solve the above-described problems, the present invention effectively utilizes a nut to be screwed with a bolt, and undergoes a temporary fixing step to obtain a temporary fixing structure with the nut, thereby joining different diameter steel pipes. The present invention has been completed based on the knowledge that a reduction in the number of processes and parts can be realized.

The present invention is two steel pipes having different outer diameters, a large diameter steel pipe and a small diameter steel pipe, wherein the large diameter steel pipe includes an inner plate projecting inside a large diameter connection end, and the small diameter steel pipe is connected to a small diameter steel pipe. An outer plate extending outward from the end, the inner plate and the outer plate having bolt insertion holes at positions that match each other, and passing the inner plate and the outer plate through the bolt insertion holes By fixing with a bolt and a nut, the large diameter steel pipe and the small diameter steel pipe are joined in the axial direction.

In this joining, the joining method of different diameter steel pipes according to the present invention includes the following three steps.

(1) The head portion of the bolt is positioned inside the tube of the inner plate and supported by a support member, and the shaft portion of the bolt is inserted so as to protrude outward from the bolt insertion hole of the inner plate, A temporary fixing step of obtaining a temporary fixing structure in which the nut is screwed onto the protruding shaft portion.
(2) removing the temporary fixing of the nut in the temporary fixing structure, passing the shaft portion of the bolt protruding outside the pipe of the inner plate through the bolt insertion hole of the outer plate, and And a mating step of matching the outer plate with the outer plate.
(3) A main fixing step in which the nut is screwed and fixed to the shaft portion of the bolt protruding from the outer plate.

In the joint structure of the present invention, the head of the bolt is in contact with the support member fixed to the inside of the large-diameter steel pipe of the inner plate, so the support member functions as a bolt detent. Can also be used.

In addition, the present invention does not use the nut only for final tightening, but also effectively uses the nut in the joining process of the different diameter steel pipes, thereby reducing the joining process of the different diameter steel pipes and the number of parts. It is possible to provide a bonding method and a bonding structure that can be realized.

Explanatory drawing of the joining structure of the different diameter steel pipes concerning embodiment of this invention. Explanatory drawing which looked at the same junction structure from the pipe inner side of the large diameter steel pipe. (A) Structural explanatory view of the support member in the joint structure viewed from the inside of the tube, (B) A sectional view of the structure cut in the width direction of the support member, (C) The structure cut in the length direction of the support member (D) Structure explanatory drawing which looked at the supporting member in other joining structures from the pipe inner side, (E) Sectional drawing which cut | disconnected other joining structures in the width direction of the supporting member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Basic structure)
The joint structure of different diameter steel pipes according to this embodiment is a structure in which a large diameter steel pipe 21 and a small diameter steel pipe 11 having different outer diameters are joined in the axial direction as in the above-described prior art document.

The large-diameter steel pipe 21 includes an inner plate 23 that protrudes to the inside of the end portion (hereinafter referred to as a large-diameter connection end). On the other hand, the small-diameter steel pipe 11 is provided with an outer plate 13 projecting outside the end portion (hereinafter referred to as a small-diameter connection end). The inner plate 23 and the outer plate 13 are fixed to respective ends of the large diameter steel pipe 21 and the small diameter steel pipe 11 by welding or the like. For fixing by welding or the like, a short auxiliary cylinder portion 22 may be provided on the inner plate 23, and the auxiliary cylinder portion 22 may be inserted into the large diameter connection end of the large diameter steel pipe 21. In addition, although illustration is abbreviate | omitted, you may implement by providing the same auxiliary | assistant cylinder part also in the outer side plate 13 of the small diameter steel pipe 11. FIG. Further, the reinforcing member may be passed between the inner plate 23 and the inner peripheral surface of the large-diameter steel pipe 21 or between the outer plate 13 and the outer peripheral surface of the small-diameter steel pipe 11 to increase its strength. Absent.

The outer plate 13 and the inner plate 23 are provided with a plurality of bolt insertion holes 14 and 24 at positions where they match each other, and the shaft portion 44 of the bolt 42 is passed through these insertion holes, and the nut 41 is screwed into this. By tightening and fixing, the outer plate 13 and the inner plate 23 are fixed in a matched state, and the small-diameter steel pipe 11 and the large-diameter steel pipe 21 are joined. The nut 41 contacts the outer plate 13 directly or through an auxiliary member such as a washer, and the head portion 43 of the bolt 42 contacts the inner plate 23 directly or through the auxiliary member.

The large-diameter steel pipe 21 is fixed in a standing manner on the ground or the like, and the small-diameter steel pipe 11 is often placed on and joined to the large-diameter steel pipe 21, but the axial direction does not necessarily need to be a vertical direction, and is a horizontal direction. It does not matter even if it is inclined. Further, in this embodiment, the large and small two-stage steel pipes 11 and 21 are connected in the axial direction, but large, medium, and small three-stage steel pipes, large, small, large and small three-stage steel pipes are connected, and multistage steel pipes are connected. The present invention can be widely applied to joining at least two stages of steel pipes, such as connecting.

(Specific structure)
A support member 31 is fixed to the inner plate 23 on the inner side of the large-diameter steel pipe 21. The support member 31 is a member made of metal or the like in which the horizontal plate portion 32 and the vertical plate portion 33 are integrally provided. The horizontal plate portion 32 is in contact with the end portion of the head portion 43 of the bolt 42, and the vertical plate portion 33 is bent from the horizontal plate portion 32 and extends upward (in a direction approaching the horizontal plate portion 32). The vertical plate portion 33 is in contact with the side portion of the head portion 43 of the bolt 42. As described above, since at least a part of the support member 31 is in contact with the head 43 of the bolt 42, it is possible to suppress the bolt 42 from being loosened due to vibration or the like.
Two vertical plate portions 33 may be provided as shown in FIGS. 2 and 3A and 3B, and two vertical plate portions 33 are provided on both sides of the horizontal plate portion 32 as shown in FIGS. Or three or more.

The support member 31 is fixed to the inner plate 23. The specific structure may be engagement, fitting, adhesion, or the like between members. In this example, fixation by a male screw 34 is employed. More specifically, as shown in FIG. 3C, a female screw 35 is formed on the support member 31 and a through hole 26 is formed on the inner plate 23. Then, from the outside of the inner plate 23, the shaft portion of the male screw 34 is inserted into the through hole 26, and is screwed and fixed to the female screw 35 of the support member 31. Since the head of the male screw 34 is disposed on the outer end surface of the inner plate 23 and the outer plate 13 is disposed thereon, the male screw 34 does not loosen unless the support member 31 rotates. And since the vertical plate part 33 is located in the side part of the head part 43 of the volt | bolt 42, the support member 31 cannot rotate. Therefore, the male screw 34 has a structure that does not loosen, and there is no possibility that the support member 31 falls off due to the loosening of the male screw 34.

In this example, as shown in FIGS. 2 and 3, two bolts 42 are supported by one support member 31, but one bolt 42 may be supported, and three or more bolts 42 may be supported. May be used.
It is desirable that at least a part of the support member 31 is in contact with the head 43 of the bolt 42. Further, the vertical plate portion 33 does not necessarily need to be in contact with the inner plate 23, but the horizontal plate portion 32 is preferably in contact with the head portion 43.

In the joint structure of the different diameter steel pipes, the structure is less likely to be loosened even when subjected to vibrations. Further, if the nut 41 is provided with an appropriate structure for preventing looseness, the structure is less likely to be loosened. Realize.

(Joining method)
Next, a method for obtaining the above-described joint structure will be described.
This method includes three steps: (1) a temporary fixing step, (2) a matching step, and (3) a main fixing step.

(1) Temporary fixing step The temporary fixing step is a step of obtaining a temporary fixing structure.
In the temporary fixing structure, the head portion 43 is positioned inside the tube of the inner plate 23 and supported by the support member 31, and the shaft portion 44 of the bolt 42 extends from the bolt insertion hole 24 of the inner plate 23 to the outside of the large-diameter steel tube 21. In this structure, the nut 41 is screwed into the protruding shaft portion 44.

Various methods are possible for the temporary fixing step, but it is realistic to go through the following three steps.
(1-1) By the work from the work opening 25 provided in the inner plate 23, the bolt insertion hole 24 of the inner plate 23 is projected to the outside of the pipe through the shaft portion 44 of the bolt 42. When this process is performed by a single worker, hold the bolt 42 in the left hand (anti-handed hand), thrust the hand into the pipe from the work opening 25, and pass the shaft portion 44 of the bolt 42 into the bolt insertion hole 24. That's fine.

The work opening 25 only needs to be large enough to allow one hand of the operator to pass through. Therefore, the inner plate 23 is suitable to have a donut shape. For example, the inner plate 23 is implemented as two plates, and these are passed to the large-diameter connection end of the large-diameter steel pipe 21 so that the space between them is a work opening. It may be 25.

(1-2) By the work from the outside of the tube of the inner plate 23, the nut 41 is screwed onto the shaft portion 44 protruding outward and temporarily fixed. When this process is performed by one worker, the nut 41 may be lightly screwed onto the shaft portion 44 of the bolt 42 while holding the bolt 42 in the right hand (dominant hand). This prevents the bolt 42 from falling off. The process (1-2) only needs to be able to prevent the bolt 42 from dropping off for a short period of time until the next process (1-3) is performed. Even workers can do it safely.
In addition, although it described also in the means for solving the above-mentioned subject, temporary fixation by the screwing of the nut 41 can be abbreviate | omitted and implemented. Temporary fixing is a powerful risk avoidance measure at sites where the removal of components during construction is dangerous, such as work at high altitudes, but in situations where it is not necessary to consider such risks, temporary fixing is required. Can be omitted.

(1-3) The head 43 of the bolt 42 is supported by the support member 31 from the inside of the tube. Specifically, the support member 31 is applied to the head portion 43, and the support member 31 is fixed to the inner plate 23 with the male screw 34. When this process is performed by one worker, the left hand holding the support member 31 is inserted from the work opening 25 and the male screw 34 is passed through the inner plate 23 with the right hand while the support member 31 is applied to the head 43. It is inserted into the hole 26 and screwed to the female screw 35 of the support member 31. If a tapping screw or the like is used for the male screw 34, the through hole 26 and the male screw 34 may not be processed in advance.

(Preparation process)
Prior to the above-described steps (1-1) to (1-3), the inner plate 23 projecting inward is fixed to the large-diameter connection end of the large-diameter steel pipe 21 by welding or the like. An outer plate 13 that projects outward is fixed to the small diameter connection end of the small diameter steel pipe 11 by welding or the like. These steps are generally performed at a factory, and after transporting them to the site and installing the large-diameter steel pipe 21, the steps (1-1) to (1-3) are performed. You may go on. In addition, the temporary fixing structure may be completed at the factory. In that case, before the inner plate 23 is fixed to the large-diameter steel pipe 21, temporary fixing by the nut 41 or the support member 31 may be performed on the inner plate 23. The inner plate 23 can be fixed to the large-diameter steel pipe 21 by welding or the like after the fixing. In other words, for example, the shaft portion 44 of the bolt 42 is inserted through the bolt insertion hole 24 of the inner plate 23, the head 43 of the bolt 42 is supported by the support member 31, and the shaft of the bolt 42 protruding from the inner plate 23. The temporary fixing structure may be obtained by preparing the inner plate 23 in which the nut 41 is screwed to the portion 44 and fixing the inner plate 23 to the connection end of the large-diameter steel pipe 21.

(2) Matching step In the matching step, the bolt 42 in the temporary fixing structure is temporarily fixed, the protruding shaft portion 44 is aligned with the bolt insertion hole 14 of the outer plate 13 and passed through the inner plate 23. This is the process of matching the plates 13. When the small-diameter steel pipe 11 is a heavy object, the work is performed by lifting the small-diameter steel pipe 11 with a crane or the like, but even in that case, only one worker is necessary for alignment at a high place. A total of two workers are only needed on site.

(3) Main fixing step The main fixing step may be carried out according to a conventional method. Specifically, the nut 41 is screwed onto the shaft portion 44 of the bolt 42 protruding from the outer plate 13 and fixed. Simply complete the work.

As described above, according to this method, different diameter pipes can be joined efficiently and safely, and the number of the outer plate 13, the inner plate 23, the support member 31, the male screw 34, the nut 41, and the bolt 42 is small. Even a member can realize bonding in which looseness is suppressed.

DESCRIPTION OF SYMBOLS 11 Small diameter steel pipe 13 Outer plate 14 Bolt insertion hole 21 Large diameter steel pipe 22 Auxiliary cylinder part 23 Inner plate 24 Bolt insertion hole 25 Work opening 26 Through hole 31 Support member 32 Horizontal plate part 33 Vertical plate part 34 Male screw 35 Female screw 41 Nut 42 Bolt 43 Head 44 Shaft

Claims (7)

A large-diameter steel pipe and a small-diameter steel pipe with different outer diameters are joined in the axial direction,
The large-diameter steel pipe includes an inner plate projecting inside the large-diameter connection end,
The small-diameter steel pipe includes an outer plate projecting outside the small-diameter connection end,
The inner plate and the outer plate are provided with bolt insertion holes at positions that match each other,
In the joint structure between the different diameter steel pipes, wherein the inner plate and the outer plate are fixed by bolts and nuts passed through the bolt insertion holes,
The shaft portion of the bolt protrudes from the bolt insertion hole of the outer plate and is screwed with the nut.
The head of the bolt is located inside the pipe of the large-diameter steel pipe of the inner plate, and is in contact with a support member fixed to the inside of the pipe of the large-diameter steel pipe of the inner plate. Characteristic joining structure of different diameter steel pipes. The support member includes a detent portion that prevents the bolt from being rotated around the head.
The said support member is being fixed with the external thread with respect to the said inner side plate, The head of the said external thread is located between the said inner side plate and the said outer side plate, The difference of Claim 1 characterized by the above-mentioned. Bonding structure between diameter steel pipes. In the joining method of the different diameter steel pipes for obtaining the joining structure of the different diameter steel pipes according to claim 1 or 2,
Passing the shaft portion of the bolt from the inner side of the inner plate of the large-diameter steel pipe to the outer side of the tube through the bolt insertion hole of the inner plate by an operation from the working opening provided in the inner plate; ,
Pressing the support member from the inside of the tube against the head of the bolt, and fixing the head of the bolt between the inner plate and the support member; and
A method for joining different diameter steel pipes. Two steel pipes with different outer diameters, a large diameter steel pipe and a small diameter steel pipe,
The large-diameter steel pipe includes an inner plate projecting inside the large-diameter connection end,
The small-diameter steel pipe includes an outer plate projecting outside the small-diameter connection end,
The inner plate and the outer plate are provided with bolt insertion holes at positions that match each other,
In the method of joining the large-diameter steel pipe and the small-diameter steel pipe in the axial direction by fixing the inner plate and the outer plate with bolts and nuts passed through the bolt insertion holes,
(1) The head portion of the bolt is positioned inside the tube of the inner plate and supported by a support member, and the shaft portion of the bolt is inserted so as to protrude outward from the bolt insertion hole of the inner plate, A temporary fixing step of obtaining a temporary fixing structure in which the nut is screwed onto the protruding shaft portion;
(2) removing the temporary fixing of the nut in the temporary fixing structure, passing the shaft portion of the bolt protruding outside the pipe of the inner plate through the bolt insertion hole of the outer plate, and A mating step for matching the outer plate with the outer plate;
(3) a main fixing step of screwing and fixing the nut to the shaft portion of the bolt protruding from the outer plate;
A method for joining different diameter steel pipes. The temporary fixing step includes
(1-1) The bolt having a head is inserted into the bolt insertion hole of the inner plate from the inner side of the inner plate of the large-diameter steel pipe by the work from the working opening provided in the inner plate. The process of passing through,
(1-2) A step of screwing the nut onto a shaft portion of the bolt protruding outward from the inner plate by work from the outside of the pipe of the inner plate, and temporarily fixing the nut;
(1-3) The method for joining different-diameter steel pipes according to claim 4, further comprising a step of supporting the head of the bolt by a support member from the inside of the pipe. The step (1-3) of the temporary fixing step is a step of screwing from the outside of the tube of the inner plate in a state where the support member is disposed inside the large diameter steel tube of the head of the bolt. The joining method of the different diameter steel pipes of Claim 5 characterized by the above-mentioned. The support member includes a horizontal plate portion disposed on an end side of the head of the bolt, and a vertical plate portion provided by being bent with respect to the horizontal plate portion,
The said vertical board part is contact | abutted to the side surface of the said head of the said bolt, and becomes a rotation stop of the said bolt in the said main fixing process, The said any one of Claims 4-6 characterized by the above-mentioned. Method of joining different diameter steel pipes.

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