Mechanical joint, joining method of mechanical joint, steel pipe, structure, construction method of structure, design method of mechanical joint, manufacturing method of mechanical joint

Abstract

To provide a mechanical joint that does not require rotation or application of a large load in joining, can transmit a torsional load without incurring additional excessive costs, and does not come off or reduce the strength, and also to provide a joining method of the mechanical joint, a steel pipe equipped with the mechanical joint, a structure including the steel pipe as a component, a construction method of the structure, a design method of the mechanical joint, and a manufacturing method of the mechanical joint.SOLUTION: A mechanical joint 1 comprises: one or more stages of annular grooves 15 formed on an outer peripheral surface of a male joint 3 and an inner peripheral surface of a female joint 5 so as to face each other when insertion is complete; a C-shaped ring member 17 that can be disposed within the annular groove 15 so as to straddle the male joint 3 side and the female joint 5 side; anti-rotation pin insertion holes 13M, 13F provided in the male joint 3 and the female joint 5; and an anti-rotation pin 11 passing through the anti-rotation pin insertion holes 13M, 13F of the female joint 5 and a C-shaped cutout portion 19 to reach the anti-rotation pin insertion holes 13M, 13F of the male joint 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mechanical joint applied to steel pipe piles and steel pipe sheet piles, a joining method for the mechanical joint, a steel pipe equipped with the mechanical joint, a structure including the steel pipe as a component, a construction method for the structure, a design method for the mechanical joint, and a manufacturing method for the mechanical joint. [Background technology]

[0002] Conventionally, steel pipe piles and steel pipe sheet piles have been connected mainly by on-site welding, but in recent years, due to a decrease in skilled workers, shortening of construction time, and quality control, the use of mechanical joints for connection has been increasing. In the case of steel pipe piles and steel pipe sheet piles, the usual method is to manufacture tubular joint members separately from the steel pipes, and then weld the joint members to the ends of the steel pipes to be joined, and then join the joint members together.

[0003] The joint must be constructed to be able to transmit the compressive, tensile, shear, and torsional loads that act on the piles during construction and operation. Compressive loads can be easily transmitted by bringing the end faces of the joint members into surface contact, and shear loads can be easily transmitted by inserting a male pipe into a female pipe to create a double-pipe structure. However, tensile and torsional loads cannot be transmitted by simple insertion and surface contact, and some ingenuity is required in the structure.

[0004] For example, Patent Document 1 (JP Patent Publication No. 10-311028) discloses a structure in which a joint member has a multiple thread shape, and the threads of the male and female joints mesh with each other through a rotary joint, allowing the transmission of tensile loads. Note that while a torsional load in the normal direction can be transmitted by fully tightening the screws, a torsional load in the reverse direction cannot be transmitted. Therefore, a bolt is arranged on the outer periphery so as to straddle the male and female joints, allowing the torsional load in the reverse direction to be transmitted by the shear of the bolt.

[0005] Also, Patent Document 2 (JP 2004-36329 A) discloses a joint structure in which a plurality of slits in the axial direction are provided in the circumferential direction on either the male joint or the female joint, and the joint members separated by the slits are processed so as to be elastically deformable in the radial direction, and the separated joint members are provided with convex portions, while the other member is provided with concave portions that engage with the convex portions when fitting is complete.The structure disclosed here allows the divided joint members to bend in the radial direction when a compressive load is applied due to their own weight or the like when inserting the joint, and when they return to their original shape at the completion of insertion, the convex portions and concave portions engage with each other, thereby transmitting a tensile load. In addition, in this structure, as in Patent Document 1, bolts are arranged on the outer peripheral surface, making it possible to transmit torsional loads.

[0006] As another method, Patent Document 3 (JP Patent Publication No. 11-36285) discloses a structure in which a groove is provided in each of the male and female joints so that their axial positions match when mating is complete, and a ring-shaped member with a changeable diameter is stored in either the male or female joint so that it fits into the groove, and when mating is complete, the ring-shaped member is moved radially and positioned so that it straddles the male and female joints, thereby transmitting tensile loads. Since this structure also cannot transmit torsional loads, it is necessary to provide a bolt as in Patent Documents 1 and 2, or to provide a separate anti-rotation mechanism as in Patent Document 4 (JP Patent Publication 2000-319874). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-311028 [Patent Document 2] JP 2004-36329 A [Patent Document 3] Japanese Patent Application Publication No. 11-36285 [Patent Document 4] JP 2000-319874 A Summary of the Invention [Problem to be solved by the invention]

[0008] In threaded joints such as that described in Patent Document 1, even if the joint is made multi-thread, it is unavoidable to rotate the steel pipe when joining, so joining can be difficult when the pipe is very large in diameter or when there is insufficient space to work in for rotation.

[0009] Furthermore, in a joint that is elastically deformed as in Patent Document 2, if the joint is thick, the load required for elastic deformation increases, and there are cases where the joint cannot be fitted by its own weight alone. It is possible to reduce the load by increasing the number of slits or lengthening them, but this increases the processing cost and reduces the shear load transmission capacity.

[0010] On the other hand, the joint disclosed in Patent Document 3 differs from Patent Documents 1 and 2 in that although a ring-shaped member is required to form the joint, it does not require rotation during joining and does not require a load for elastic deformation.

[0011] However, as mentioned above, the device in Patent Document 3 which uses a ring-shaped member cannot transmit torsional loads, so it is necessary to either place a bolt as in Patent Documents 1 and 2, or to place a separate anti-rotation mechanism as in Patent Document 4. However, in the case of Patent Document 3, even if bolts are placed as in Patent Documents 1 and 2, or a separate anti-rotation mechanism is provided as in Patent Document 4, the ring-shaped member itself is in a state where it can rotate and deform, so there is a concern that the ring-shaped member may behave in an unexpected way during construction or service, causing the joint to come loose or reducing the strength.

[0012] The present invention has been made to solve these problems, and has an object to provide a mechanical joint that does not require rotation or application of a large load to the joint, can transmit torsional loads without incurring excessive additional costs, and does not come loose or lose its strength. Another object of the present invention is to provide a method for joining the mechanical joint, a steel pipe equipped with the mechanical joint, a structure having the steel pipe as a component, a construction method for the structure, a design method for the mechanical joint, and a manufacturing method for the mechanical joint. [Means for solving the problem]

[0013] (1) A mechanical joint according to the present invention comprises a tubular male joint and a female joint into which the male joint is inserted and fitted, and is attached to the end of a steel pipe to join the steel pipes together, a step portion is formed on the base end side of the male joint, and when the male joint is inserted into the female joint, the tip portion of the female joint abuts on the step portion to reach an insertion complete state, and the connector comprises one or more steps of annular grooves formed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion complete state, a C-shaped ring member that can be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint and that can be arranged to straddle the male joint side and the female joint side within the annular groove in the insertion complete state, an anti-rotation pin insertion hole provided in the male joint and the female joint at a position that coincides with a C-shaped cutout portion in the C-shaped ring member, and an anti-rotation pin that passes through the anti-rotation pin insertion hole and the C-shaped cutout portion of the female joint in the insertion complete state to reach the anti-rotation pin insertion hole of the male joint.

[0014] (2) Moreover, a method for joining a mechanical joint according to the present invention is a method for joining a mechanical joint according to the above (1), The C-shaped ring is inserted with the C-shaped notch aligned with the anti-rotation pin insertion hole of the male joint. Materials reducing the diameter of the male connector to accommodate it in the annular groove of the male connector; a step of completing insertion of the male joint and the female joint in a state in which the positions of the rotation prevention pin insertion holes of the male joint and the female joint are aligned; 2. C-shaped ring Materials Releasing the reduced diameter state; and disposing the anti-rotation pin in a state in which the anti-rotation pin passes through the anti-rotation pin insertion hole and the C-shaped notch portion and reaches the anti-rotation pin insertion hole of the male joint.

[0015] (3) Furthermore, a steel pipe according to the present invention has the male joint and female joint described in (1) attached to one end and the other end.

[0016] (4) The structure according to the present invention includes a plurality of steel pipes connected by the mechanical joint described in (1) above.

[0017] (5) Furthermore, the construction method of the structure of the present invention is a construction method of the structure described in (4) above, in which, while restraining the axial position of one of the steel pipes with fittings to be connected, the other steel pipe with fitting is aligned with the one of the steel pipes with fittings and inserted into it.

[0018] (6) Furthermore, a design method for a mechanical joint according to the present invention is a design method for a mechanical joint that includes a tubular male joint and a female joint into which the male joint is inserted and fitted, and that is attached to an end of a steel pipe to join the steel pipes, the design method comprising the steps of: A step portion is provided on the base end side of the male joint, a tip end of the female joint is set to abut against the step portion when the male joint is completely inserted into the female joint; one or more stages of annular grooves are disposed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion completion state, a C-shaped ring member is set so as to be able to be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and so as to be able to be arranged so as to straddle the male joint side and the female joint side within the annular groove in the insertion completion state; a rotation prevention pin insertion hole provided in the male joint and the female joint is set at a position that coincides with a C-shaped notch portion of the C-shaped ring member; In the insertion complete state, an anti-rotation pin is set which passes through the anti-rotation pin insertion hole and the C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint.

[0019] (7) Furthermore, a method for manufacturing a mechanical joint according to the present invention is a method for manufacturing a mechanical joint that includes a tubular male joint and a female joint into which the male joint is inserted and fitted, the mechanical joint being attached to an end of a steel pipe to join the steel pipes together, the method comprising the steps of: A step portion is formed on the base end side of the male joint, The male joint is formed so that a tip portion of the female joint abuts on the step portion when the male joint is completely inserted into the female joint, one or more stages of annular grooves are formed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion completion state, a C-shaped ring member is formed so as to be able to be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and so as to be able to be arranged so as to straddle the male joint side and the female joint side within the annular groove when the insertion is completed; a rotation prevention pin insertion hole is formed in the male joint and the female joint at a position that coincides with a C-shaped notch portion of the C-shaped ring member; In the inserted state, an anti-rotation pin is formed which passes through the anti-rotation pin insertion hole and the C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint. Effect of the Invention

[0020] In the present invention, annular grooves are provided in the male joint and the female joint, and when the male joint is fully inserted into the female joint, a C-shaped ring member is positioned so as to straddle both the male joint and the female joint, and an anti-rotation pin is provided that passes through the anti-rotation pin insertion hole and C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint when the insertion is complete.This eliminates the need to apply rotation or large loads to the joint, and allows torsional loads to be transmitted without incurring excessive additional costs. Furthermore, since the C-shaped notch does not close, the joint will not come loose or its strength will not decrease. Furthermore, since the anti-rotation pin serves both to prevent rotation of the male and female joints and to prevent the C-ring member from shrinking or moving, reliable load transmission is possible with a simple structure. [Brief description of the drawings]

[0021] [Figure 1] 1A is an explanatory diagram of a mechanical joint according to embodiment 1, in which FIG. 1A is a vertical cross-sectional view (upper view in the figure (same below)) and a cross-sectional view taken along line AA in the vertical cross-sectional view (lower view in the figure (same below)), FIG. 1B is a vertical cross-sectional view and a cross-sectional view taken along line BB in the vertical cross-sectional view (however, cutting tool 22 is omitted), FIG. 1C is a vertical cross-sectional view and a cross-sectional view taken along line CC in the vertical cross-sectional view (however, anti-rotation pin 11 is omitted), and FIG. 1D is a vertical cross-sectional view and a cross-sectional view taken along line DD in the vertical cross-sectional view (however, anti-rotation pin 11 is omitted). [Diagram 2] 6A to 6C are explanatory views of another aspect of the method for reducing the diameter of the C-shaped ring member in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A mechanical joint according to this embodiment will be described with reference to Fig. 1. Fig. 1(a) shows the state before the joint is inserted, Fig. 1(b) shows the state after the joint is inserted and before the C-shaped ring member is contracted and released, Fig. 1(c) shows the state after the C-shaped ring member is contracted and released and before the anti-rotation pin is inserted, and Fig. 1(d) shows the state after the anti-rotation pin 11 is inserted.

[0023] As shown in Fig. 1(a), the mechanical joint 1 according to this embodiment comprises a tubular male joint 3 and a female joint 5 into which the male joint 3 is inserted and fitted, and is attached to the ends of steel pipes 7 to join the steel pipes 7 together. A step portion 9 is formed on the base end side of the male joint 3, and as shown in Fig. 1(b), when the male joint 3 is inserted into the female joint 5, a tip portion 10 of the female joint 5 abuts against the step portion 9, completing the insertion.

[0024] Further, the male joint 3 and the female joint 5 are provided with anti-rotation pin insertion holes 13M, 13F into which an anti-rotation pin 11 is inserted. The anti-rotation pin insertion holes 13M, 13F may be tapped holes on both the male joint 3 and the female joint 5, or only one of the male joint 3 or the female joint 5 may be a threaded hole. However, if either one is a threaded hole, it is preferable to have the female joint 5 side be a threaded hole because this makes it easier to install the anti-rotation pin 11.

[0025] Further, annular grooves 15 are formed on the outer peripheral surface of the male joint 3 and the inner peripheral surface of the female joint 5 so as to face each other when the insertion is complete. The annular grooves 15M, 15F formed in the male joint 3 and the female joint 5 respectively form annular groove 15 consisting of a circular closed space when the joints are in a fully inserted state. Furthermore, it has a C-shaped ring member 17 that is stored in a reduced diameter state in the annular groove 15M of the male joint 3 so as not to hinder insertion of the male joint 3 into the female joint 5, and that can be positioned within the annular groove 15 so as to straddle the annular groove 15M of the male joint 3 and the annular groove 15F of the female joint 5 when the reduced diameter state is released.

[0026] As shown in FIG. 1, the C-shaped ring member 17 has a notch 19 at one location in the circumferential direction, and has a spring structure that expands and contracts in the radial direction. The C-shaped ring member 17 has a diameter larger than the outer diameter of the annular groove 15M in a free, unconstrained state. Therefore, in order to completely fit into the annular groove 15M, a diameter reduction holding means is required to hold the C-shaped ring member 17 in a reduced diameter state. One example of the diameter reduction holding means is a fixing tape 21 that is attached so as to straddle the notch 19 in the reduced diameter state of the C-shaped ring member 17. By attaching the fixing tape 21 to hold the reduced diameter state, the C-shaped ring member 17 is disposed in the annular groove 15M in a state that is aligned with the outer circumferential surface of the annular groove 15M of the male joint 3. It is preferable that the diameter of the anti-rotation pin insertion hole 13M is larger than the width of the annular groove 15M for the following reasons. If the diameter of the anti-rotation pin insertion hole 13M is larger than the width of the annular groove 15M, when the C-shaped ring member 17 is contracted and stored in the annular groove 15M, the anti-rotation pin insertion hole 13M will not be completely covered, and part of the anti-rotation pin insertion hole 13M will be visible above and below the C-shaped ring member 17. In this state, the fixing tape 21 can reach not only the front surface of the C-shaped ring member 17, but also the side and rear surfaces, so that the fixing tape 21 can be wrapped around the entire circumference of the C-shaped ring member 17 near the cutout portion 19 and secured firmly in place.

[0027] The fixing tape 21 is preferably made of, for example, an adhesive tape, is thin, can be easily fastened with fingers, and is made of a material that is resistant to water and oil. Furthermore, since the fixing tape 21 will be later cut or removed to release the diameter-reduced state of the C-shaped ring member 17, it needs to be cuttable, such as made of resin, or removable even if it cannot be cut.

[0028] The fixing tape 21 attached to the C-shaped ring member 17 must be cut by inserting a tool through the anti-rotation pin insertion hole 13F once the male joint 3 has been completely inserted into the female joint 5. For this reason, the C-shaped ring member 17 is disposed in the annular groove 15M of the male joint 3 so that the cutout 19 is at the position of the anti-rotation pin insertion hole 13M.

[0029] The fitting operation of the mechanical joint 1 configured as above will be described. 1(a), before the male joint 3 is inserted into the female joint 5, the C-shaped ring member 17 is stored in the annular groove 15M of the male joint 3 in a reduced diameter state, and the fixing tape 21 prevents the C-shaped ring member 17 from expanding in diameter. Then, the male joint 3 and the female joint 5 are aligned, and the male joint 3 is inserted into the female joint 5. Incidentally, aligning the directions of the male joint 3 and the female joint 5 means that the positions of the anti-rotation pin insertion holes 13M, 13F of the male joint 3 and the female joint 5 are aligned.

[0030] 1(b), insertion of the male joint 3 into the female joint 5 is completed when the step portion 9 of the male joint 3 and the tip of the female joint 5 are in contact. In this state, the annular grooves 15 formed in the male joint 3 and the female joint 5 respectively form an annular groove 15 consisting of an elliptical closed space, and the C-shaped ring member 17 stored in the annular groove 15M of the male joint 3 is disposed opposite the annular groove 15F of the female joint 5.

[0031] Next, a cutting tool 22 such as a cutter is inserted through the anti-rotation pin insertion hole 13F of the female joint 5 to cut the fixing tape 21 (FIG. 1(b)). As a result, as shown in FIG. 1(c), the C-shaped ring member 17 is expanded in diameter by its own spring force, and the C-shaped ring member 17 is positioned so as to straddle both the annular groove 15M and the annular groove 15F.

[0032] Next, the anti-rotation pin 11 is disposed so as to pass through the anti-rotation pin insertion hole 13F and the cutout portion 19 of the female joint 5 and reach the anti-rotation pin insertion hole 13M of the male joint 3 (FIG. 1(d)). As a result, the female joint 5 and the male joint 3 are connected by the anti-rotation pin 11, and the C-ring member 17 is prevented from moving and expanding / contracting within the annular groove 15 by the anti-rotation pin 11.

[0033] In this state, the compressive force is mainly transmitted by the contact pressure between the step portion 9 of the male joint 3 and the tip portion 10 of the female joint 5, the tensile force is mainly transmitted by the supporting pressure of the C-ring member 17, the torsional force is transmitted by the anti-rotation pin 11, and the shear force is mainly transmitted by the double pipe portion formed by the male joint 3 and the female joint 5.

[0034] As described above, in this embodiment, annular grooves 15M, 15F are provided in the male joint 3 and the female joint 5, and when the male joint 3 is completely inserted into the female joint 5, the C-shaped ring member 17 is arranged to straddle the annular grooves 15 of both the male joint 3 and the female joint 5. Furthermore, by providing an anti-rotation pin 11, there is no need to apply rotation or large loads to the joint, and tensile loads, torsional loads, and shear loads can be transmitted without incurring excessive additional costs. As described above, the C-shaped ring member 17 is prevented from moving or expanding / contracting by the anti-rotation pin 11, so that the C-shaped ring member 17 will not move unexpectedly, and the joint will not come loose or its strength will not decrease. Furthermore, since the anti-rotation pin 11 serves both to prevent rotation of the male joint 3 and the female joint 5 and to prevent movement of the C-ring member 17, reliable load transmission is possible with a simple structure.

[0035] In the above embodiment, the C-shaped ring member 17 is disposed horizontally, i.e., disposed perpendicular to the axis of the male joint 3 and the female joint 5, but the present invention is not limited to this, and the C-shaped ring member 17 may be disposed at an incline. In this case, the annular grooves 15M, 15F provided in the male joint 3 and the female joint 5 may be inclined. When the annular groove 15 is inclined, the shape and size of the C-shaped ring member 17 may be set so that it can be stored in the inclined annular groove 15 . It is preferable to arrange the C-shaped ring member 17 horizontally. A horizontal arrangement makes it easy to process the C-shaped ring member 17 and the annular groove 15, and also allows the lengths of the male joint 3 and the female joint 5 to be shortened, thereby reducing manufacturing costs.

[0036] In the above embodiment, the fixing tape 21 is exemplified as the diameter reduction holding means for holding the C-shaped ring member 17 in a diameter reduced state. However, instead of this, for example, a fixing band 23 made of polypropylene (PP band) or the like may be used. FIG. 2 shows a state in which the C-shaped ring member 17 is accommodated in the inclined annular groove 15 with its diameter reduced by the fixing band 23. The fixing band 23 is preferably made of a material that is thin, can be easily fastened by fingers, and is resistant to water and oil. The fixing band 23 fixes (fastens) the entire circumference of the C-shaped ring member 17, thereby preventing the C-shaped ring member 17 from expanding in diameter.

[0037] The method of storing the C-ring member 17 in a reduced diameter state in the annular groove 15M of the male joint 3 by the fixing band 23 is as follows. The C-shaped ring member 17 is stored in the annular groove 15M, the entire circumference of the stored C-shaped ring member 17 is covered with a fixing band 23, and the fixing band 23 is tightened to reduce the diameter of the C-shaped ring member 17, and in this state, the fixing band 23 is fixed. Like the fixing tape 21, the fixing band 23 is cut or removed after the insertion of the male joint 3 is completed.

[0038] In addition, in the above embodiment, an example was given in which the annular groove 15 is formed with one stage, but the present invention is not limited to this, and the number of stages of the annular groove 15 may be multiple stages in the central axial direction of the joint. By using multiple stages, greater load transmission is possible.

[0039] Furthermore, the above embodiment is directed to a mechanical joint 1 that is fixed to the end of a steel pipe 7 by welding or the like, but by attaching such a mechanical joint 1 to one end and the other end of a steel pipe 7, a steel pipe 7 that can be easily joined can be formed. Moreover, by connecting steel pipes 7 to which mechanical joints 1 are attached, a structure joined by mechanical joints 1 can be formed. Furthermore, to construct such a structure, while restraining the position in the axial direction of one of the jointed steel pipes 7 to be connected, the other jointed steel pipe 7 is aligned with the one jointed steel pipe 7 and inserted and fitted into it.

[0040] Furthermore, the above embodiment relates to the mechanical joint 1 as an invention of a product, but it can also be reconstructed as an invention of a design method or a manufacturing method, in which case it would be as follows.

[0041] <Invention of design method> A design method for a mechanical joint comprising a tubular male joint and a female joint into which the male joint is inserted and fitted, the mechanical joint being attached to an end of a steel pipe to join the steel pipes together, comprising: A step portion is provided on the base end side of the male joint, a tip end of the female joint is set to abut against the step portion when the male joint is completely inserted into the female joint; one or more stages of annular grooves are disposed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion completion state, a C-shaped ring member is set so as to be able to be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and so as to be able to be arranged so as to straddle the male joint side and the female joint side within the annular groove in the insertion completion state; a rotation prevention pin insertion hole provided in the male joint and the female joint is set at a position that coincides with a C-shaped notch portion of the C-shaped ring member; A method for designing a mechanical joint that sets an anti-rotation pin that passes through the anti-rotation pin insertion hole and the C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint in the inserted state.

[0042] <Production method invention> A manufacturing method for a mechanical joint comprising a tubular male joint and a female joint into which the male joint is inserted and fitted, the female joint being attached to an end of a steel pipe to join the steel pipes, the manufacturing method comprising the steps of: A step portion is formed on the base end side of the male joint, The male joint is formed so that a tip portion of the female joint abuts on the step portion when the male joint is completely inserted into the female joint, one or more stages of annular grooves are formed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion completion state, a C-shaped ring member is formed so as to be able to be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and so as to be able to be arranged so as to straddle the male joint side and the female joint side within the annular groove when the insertion is completed; a rotation prevention pin insertion hole is formed in the male joint and the female joint at a position that coincides with a C-shaped notch portion of the C-shaped ring member; A manufacturing method for a mechanical joint, which forms an anti-rotation pin that passes through the anti-rotation pin insertion hole and the C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint in the inserted state. [Explanation of symbols]

[0043] 1 Mechanical coupling 3 Male Connector 5 Female fitting 7 Steel pipe 9 Step 10 Tip 11 Anti-rotation pin 13M Anti-rotation pin insertion hole (male joint) 13F Anti-rotation pin insertion hole (female joint) 15 Annular groove 15M Annular groove (male joint) 15F Annular groove (female fitting) 17 C-ring component 19 Notch 21 Fixing Tape 22 Cutting tools 23 Fixing band

Claims

1. A mechanical joint comprising a tubular male joint and a female joint into which the male joint is inserted and fitted, the mechanical joint being attached to the end of a steel pipe to join the steel pipes together, a step portion is formed on a base end side of the male joint, and when the male joint is inserted into the female joint, a tip end of the female joint abuts on the step portion to reach an insertion complete state, the mechanical joint comprising: one or more steps of annular grooves formed on each of an outer peripheral surface of the male joint and an inner peripheral surface of the female joint so as to face each other in the insertion complete state; a C-shaped ring member that can be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and that can be arranged to straddle the male joint side and the female joint side within the annular groove in the insertion complete state; anti-rotation pin insertion holes provided in the male joint and the female joint at positions that coincide with C-shaped cutout portions of the C-shaped ring member; and an anti-rotation pin that passes through the anti-rotation pin insertion hole and the C-shaped cutout portion of the female joint in the insertion complete state to reach the anti-rotation pin insertion hole of the male joint.

2. A method for joining a mechanical joint according to claim 1, comprising the steps of: a step of reducing a diameter of the C-shaped ring member and accommodating it in the annular groove of the male joint while aligning the position of the C-shaped cutout portion with the position of the anti-rotation pin insertion hole of the male joint; a step of completing insertion of the male joint and the female joint in a state in which the positions of the rotation prevention pin insertion holes of the male joint and the female joint are aligned; releasing the C-ring member from its reduced diameter state; and arranging the anti-rotation pin in a state in which the anti-rotation pin passes through the anti-rotation pin insertion hole and the C-shaped notch portion and reaches the anti-rotation pin insertion hole of the male joint.

3. A steel pipe having the male joint and female joint according to claim 1 attached to one end and the other end.

4. A structure comprising a plurality of steel pipes connected by the mechanical joint according to claim 1.

5. A construction method for a structure as described in claim 4, in which, while restraining the axial position of one of the jointed steel pipes to be connected, the other jointed steel pipe is aligned with the one jointed steel pipe and inserted into it.

6. A design method for a mechanical joint that includes a tubular male joint and a female joint into which the male joint is inserted and fitted, and that is attached to an end of a steel pipe to join the steel pipes, comprising: A step portion is provided on the base end side of the male joint, a tip end of the female joint is set to abut against the step portion when the male joint is completely inserted into the female joint; one or more stages of annular grooves are disposed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion completion state, a C-shaped ring member is set so as to be able to be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and so as to be able to be arranged so as to straddle the male joint side and the female joint side within the annular groove when the insertion is completed; a rotation prevention pin insertion hole provided in the male joint and the female joint is set at a position that coincides with a C-shaped notch portion of the C-shaped ring member; A method for designing a mechanical joint that sets an anti-rotation pin that passes through the anti-rotation pin insertion hole and the C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint in the inserted state.

7. A manufacturing method for a mechanical joint comprising a tubular male joint and a female joint into which the male joint is inserted and fitted, the female joint being attached to an end of a steel pipe to join the steel pipes, A step portion is formed on the base end side of the male joint, The male joint is formed so that a tip portion of the female joint abuts on the step portion when the male joint is completely inserted into the female joint, one or more stages of annular grooves are formed on the outer peripheral surface of the male joint and the inner peripheral surface of the female joint so as to face each other in the insertion completion state, a C-shaped ring member is formed so as to be able to be stored in the annular groove of the male joint so as not to hinder the insertion of the male joint into the female joint, and so as to be able to be arranged so as to straddle the male joint side and the female joint side within the annular groove when the insertion is completed; a rotation prevention pin insertion hole is formed in the male joint and the female joint at a position that coincides with a C-shaped notch portion of the C-shaped ring member; A manufacturing method for a mechanical joint, in which an anti-rotation pin is formed that passes through the anti-rotation pin insertion hole and the C-shaped notch of the female joint and reaches the anti-rotation pin insertion hole of the male joint in the inserted state.

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