JP2018048543A - Steel pipe connection mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel pipe connection mechanism for not moving a key member in the circumferential direction, even if a large load in the steel pipe axial direction and the circumferential direction acts from an inward groove part and an outward groove part on the key member of connecting an axial joint and a cylindrical joint in a slipping-out prevention state.SOLUTION: A cylindrical joint 10 is provided with a through-hole communicating with the inside of an inward groove part from a cylindrical joint outer peripheral surface, and a divided key member 31 is provided with a hole part 32 opposed to the through-hole, and a fixing member 51 can be installed in the through-hole, and the fixing member 51 is provided with a conical part 53 where the base end continuing with one end side of a trunk part of the fixing member 51 is larger than a diameter of the hole part 32 and the tip is smaller than the diameter of the hole part 32, and the divided key member 31 is fixed to a straddling position by contacting the conical part 53 with the hole part 32, and the divided key member 31 is locked in moving along the circumferential direction.SELECTED DRAWING: Figure 8

Description

  The present invention provides a tubular joint provided at one of the steel pipe end portions facing each other of steel pipes adjacent to each other in the axial direction of the steel pipe, and a shaft shape provided at the other steel pipe end portion and capable of fitting into the tubular joint. A joint, an accommodation position where the tubular joint inner peripheral surface of the cylindrical joint is provided in an inward groove provided along the circumferential direction from the inner peripheral surface of the cylindrical joint, the cylindrical joint, and the shaft An outward groove and an inward groove provided on the outer peripheral surface of the shaft-like joint of the shaft-like joint so as to face the inward groove along the circumferential direction when the joint is fitted to each other; It is related with the steel pipe connection mechanism which has the straddle position straddling and the key member arrange | positioned so that a position change is possible.

  In Patent Document 1, a cylindrical joint provided at one of steel pipe end portions facing each other of steel pipes adjacent to each other in the axial direction of the steel pipe, and provided at the other steel pipe end portion, can be fitted to the cylindrical joint. A shaft-like joint, a housing position that enters an inward groove provided along the circumferential direction of the cylindrical joint inner peripheral surface of the cylindrical joint from the inner peripheral surface of the cylindrical joint, the cylindrical joint, and the An outward groove portion and an inward direction provided on the outer peripheral surface of the shaft-like joint of the shaft-like joint so as to face the inward groove portion along the circumferential direction when the shaft-like joint is fitted to each other. A steel pipe coupling mechanism having a straddling position straddling the groove and a key member arranged to be capable of changing the position is disclosed.

  The key member is operated from the outer peripheral portion of the cylindrical joint with a set bolt having one end screwed into a female screw provided in the cylindrical joint and the other end screwed into a female screw provided in the key member. Thus, the position can be changed between the accommodation position and the straddling position.

JP 2000-319874 A

  The steel pipes connected by the steel pipe connection mechanism are used for various applications such as building support piles, steel pipe piles, steel pipe sheet piles, landslide prevention piles, earth retaining column train piles, structural columns, etc. A large load in the axial direction of the steel pipe or the circumferential direction acts on the coupling mechanism, in particular, the key member from the inward groove portion and the outward groove portion.

  Since the inward groove portion and the outward groove portion have a slight clearance with respect to the key member, the key member is moved in the longitudinal direction and the circumferential direction in the inward groove portion and the outward groove portion.

  If the set bolt loosens or breaks due to this movement, the key member may move along the circumferential direction, and the shaft joint and the cylindrical joint may not be removed.

  The present invention has been made in view of the above-described circumstances, and the key member connecting the shaft-shaped joint and the tubular joint in a retaining state is connected to the steel pipe axial direction and circumferential direction from the inward groove portion and the outward groove portion. An object of the present invention is to provide a steel pipe coupling mechanism in which a key member does not move in the circumferential direction even when a large load is applied.

  In order to achieve the above-described object, the characteristic structure of the steel pipe coupling mechanism of the present invention includes a cylindrical joint provided at one of the steel pipe end portions facing each other in the steel pipe adjacent to each other in the axial direction of the steel pipe, and the other steel pipe end. A cylindrical joint that can be fitted to the cylindrical joint, and an inner circumferential surface of the cylindrical joint that is provided in an inward groove provided along a circumferential direction of the cylindrical joint inner circumferential surface of the cylindrical joint. The inward groove portion along the circumferential direction on the outer surface of the shaft joint of the shaft joint when the tubular position and the shaft joint are fitted to each other. A steel pipe coupling mechanism having a key member disposed so as to be capable of changing a position at an overlying groove portion straddling the outward groove portion and the inward groove portion provided so as to face each other, wherein the tubular joint Is provided with a through hole that communicates from the outer peripheral surface of the cylindrical joint into the inward groove portion. The key member is provided with a hole portion facing the through hole, and a fixing member can be attached to the through hole, and a base end connected to the one end side is a diameter of the hole portion at one end side of the fixing member. The diameter-reduced portion is larger and the tip is smaller than the diameter of the hole, and the fixing member comes into contact with the hole from the distal end to the base end of the reduced-diameter portion so that the key member is It is in the point which can be fixed to the straddling position.

  When the shaft joint is fitted to the cylindrical joint, the key member is pushed from the housing position to the straddling position through the through hole from the outer peripheral side of the tubular joint by the fixing member, and fixed to the straddling position. The shaft-like joint and the tubular joint are connected in a retaining state. In that case, when the diameter-reduced part provided in the fixing member contacts the hole provided in the key member, the key member is locked from moving along the circumferential direction.

  In the present invention, it is preferable that the diameter-reduced portion gradually decreases in diameter from the proximal end to the distal end at a constant rate. In the present invention, it is preferable that the diameter-reduced portion gradually decreases in diameter from the proximal end to the distal end at a different rate. Furthermore, in the present invention, it is preferable that the diameter-reduced portion gradually decreases in diameter in the middle from the base end to the tip end.

  As for the reduced diameter portion, the outer peripheral surface from the front end to the base end is the boundary peripheral portion between the surface of the key member and the inner peripheral surface of the hole portion or the hole portion while the front end enters the hole portion of the key member By making contact with the inner peripheral surface, the key member is reliably locked to move in the circumferential direction.

  In the present invention, it is preferable that a female screw is provided on the inner peripheral surface of the through hole, and a male screw that can be screwed into the female screw is provided on the other end side of the fixing member.

  The key member can be pushed from the storage position to the straddling position by the fixing member.

  In the present invention, the hole is provided with a counterbore and a female screw to which a holding member for holding the key member in the accommodation position from the outer peripheral side of the cylindrical joint can be screwed. The reduced diameter portion is preferably in contact with the counterbore.

  The fixing member locks the movement of the key member along the circumferential direction by contacting the counterbore without contacting the female screw, so that there is no possibility of damaging the female screw. The key member can be pulled back to the accommodation position by screwing, for example, a hexagon bolt into the female screw of the key member located at the straddling position.

  In the present invention, the hole is provided with a countersink and a female screw to which a holding member for holding the key member in the accommodation position can be screwed from the outer peripheral side of the cylindrical joint through the through hole. The reduced diameter portion is preferably in contact with the counterbore.

  The fixing member locks the movement of the key member along the circumferential direction by making contact with the countersunk hole without contacting the female screw, so that there is no possibility of damaging the female screw. The key member can be pulled back to the accommodation position by screwing, for example, a hexagon bolt into the female screw of the key member located at the straddling position.

Explanatory drawing which cuts and shows the steel pipe pile connected by the steel pipe connection mechanism partially Illustration of steel pipe connection mechanism Sectional view enlarging the main part of the steel pipe coupling mechanism Sectional view enlarging the main part of the steel pipe coupling mechanism Illustration of steel pipe connection mechanism Illustration of steel pipe connection mechanism Illustration of steel pipe connection mechanism Sectional view enlarging the main part of the steel pipe coupling mechanism Side cross-sectional view of steel pipe coupling mechanism Sectional view enlarging the main part of the steel pipe coupling mechanism Sectional view enlarging the main part of the steel pipe coupling mechanism Sectional drawing which expanded the principal part of the steel pipe connection mechanism of another embodiment. Sectional drawing which expanded the principal part of the steel pipe connection mechanism of another embodiment. Sectional drawing which expanded the principal part of the steel pipe connection mechanism of another embodiment. Sectional drawing which expanded the principal part of the steel pipe connection mechanism of another embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows steel pipe piles P (P1, P2) used in a medium excavation method in which a rotary press-fitting into the ground is performed while excavating with an auger.

  The steel pipe pile P (P1, P2) has a cylindrical joint 10 welded to one end of a steel pipe S (S1, S2) such as a spiral steel pipe, and a shaft joint 20 welded to the other end. Cylinder.

  The steel pipe ends of the steel pipes S (S1, S2) facing each other in the steel pipe piles P (P1, P2) adjacent to each other in the direction X of the steel pipe axis are prevented from being detached by the steel pipe coupling mechanism J of the present invention. Connected in a stopped state.

  The steel pipe coupling mechanism J includes a tubular joint 10, a shaft joint 20, a load transmission key 30, and a rotation suppression key 40.

  The tubular joint 10 is created by processing a steel tubular body. As shown in FIG. 2, the cylindrical joint 10 is provided with a ridge 11 on the lower end side and a plurality of cylindrical cutout recesses 12 spaced apart in the circumferential direction. A circumferential groove 14 is provided on the upper end side of the inner peripheral surface 13 of the tubular joint 10. The inner peripheral surface 13 in the present embodiment is the cylindrical joint inner peripheral surface according to the present invention.

  Two inward groove portions 15 are provided on the inner peripheral surface 13 along the circumferential direction. Each inward groove 15 is formed deeper than the thickness of a load transmission key 30 (divided key member 31) described later. As a result, as shown in FIGS. 3 and 4, the split key member 31 can be accommodated in an accommodation position that is located inward of the inner circumferential surface 13 in the inward groove portion 15.

  The shaft-like joint 20 is created by processing a steel tubular body. As shown in FIG. 2, the upper end side of the shaft-like joint 20 is provided with a protrusion 21 that can be fitted in the circumferential groove 14 provided in the tubular joint 10.

  When the cylindrical joint 10 and the shaft-shaped joint 20 are fitted to each other, the shaft-side notch recess 22 is provided at a position facing the cylinder-side notch recess 12 provided in the cylindrical joint 10. Yes. The cylinder side cutout recess 12 and the shaft side cutout recess 22 constitute a key groove portion of a rotation suppression key 40 described later. A female screw 26 to which a fixing screw 41 for fixing the rotation suppression key 40 to the key groove portion can be screwed is provided at the central portion of the shaft-side notch recess 22 (see FIG. 1).

  The outer peripheral surface 23 has a length in the steel pipe axis X direction that is substantially the same as the length of the inner peripheral surface 13 of the cylindrical joint 10 in the steel pipe axis X direction, and has an outer diameter that can be fitted to the inner peripheral surface 13. It is configured. The outer peripheral surface 23 in this embodiment is a shaft-shaped joint outer peripheral surface according to the present invention.

  On the lower end side of the outer peripheral surface 23, a circumferential groove 24 into which the protrusion 11 provided in the tubular joint 10 can be fitted is formed.

  Two outwardly extending grooves 25 are formed on the outer peripheral surface 23 along the circumferential direction so as to face the inwardly extending grooves 15 when the tubular joint 10 and the shaft-shaped joint 20 are fitted to each other. Is provided.

  The load transmission key 30 is a member for connecting the tubular joint 10 and the shaft joint 20 in a retaining state when the tubular joint 10 and the shaft joint 20 are fitted to each other. In this embodiment, it is composed of six divided key members 31 around the steel pipe axis X. The load transmission key 30 (divided key member 31) in the present embodiment is a key member according to the present invention.

  The split key member 31 is an arcuate steel member having a rectangular cross section and an inner circumferential surface of the key facing the bottom surface of the outward groove 25 having substantially the same curvature as the bottom surface (see FIG. 4).

  By the fixing member 51 described later, the split key member 31 is pushed from the accommodation position accommodated in the inward groove portion 15 to the straddling position straddling the inward groove portion 15 and the outward groove portion 25 facing each other. The cylindrical joint 10 and the shaft-shaped joint 20 are connected in a retaining state. Further, the split key member 31 is pulled back from the straddling position to the accommodation position by a hexagon bolt 50 described later, thereby releasing the connection between the tubular joint 10 and the shaft joint 20.

  The groove depth of the outward groove portion 25 is configured to be approximately half of the thickness along the radial direction of the steel pipe pile P (P1, P2) of the split key member 31, and when the split key member 31 is in the straddling position In addition, the split key member 31 is disposed so as to straddle the inward groove portion 15 and the outward groove portion 25 substantially evenly.

  As shown in FIG. 3, through-holes 16 having a circular cross section that communicate with the tubular joint 10 from the outer peripheral surface thereof into the inward groove portion 15 are equally spaced in the circumferential direction corresponding to each divided key member 31. It is provided at six locations. A female screw 18 capable of screwing a male screw 52 provided in a fixing member 51 described later is provided on the inner peripheral surface of the through hole 16 (see FIG. 8).

  As shown in FIG. 8, a hole 32 that penetrates in the thickness direction is formed at the center position in the longitudinal direction and the height direction of the split key member 31. A counterbore 33 and an internal thread 34 are provided in the hole 32.

  As shown in FIG. 3, the hexagonal bolt 50 loosely inserted into the through hole 16 when the split key member 31 is disposed in the inward groove portion 15 so that the hole portion 32 faces the through hole 16. Is screwed into the female screw 34 of the split key member 31 so that the split key member 31 is held in the storage position. The hexagon bolt 50 in this embodiment is a holding member according to the present invention.

  Moreover, the split key member 31 can be pulled back to the storage position by screwing the hexagon bolt 50 loosely inserted through the through hole 16 into the female screw 34 of the split key member 31 located at the straddling position. .

  As shown in FIG. 8, the fixing member 51 that can be attached to the through hole 16 is provided with a male screw 52 that can be screwed into the female screw 18 of the through hole 16 around the cylindrical body portion. A conical portion 53 is provided on one end side of the body portion, and a hole portion 54 into which a tool such as a hexagon wrench for screwing the fixing member 51 screwed into the through hole 16 can be fitted is provided on the other end side. It has been. Note that the length of the fixing member 51 is configured so as not to protrude from the outer peripheral surface of the tubular joint 10 when the split key member 31 is pushed into the straddling position.

  The conical portion 53 is configured such that a base end connected to one end side of the body portion is larger than a diameter of the hole portion 32, a distal end is smaller than a diameter of the hole portion 32, and the distal end is inserted into the female screw 34. Does not contact the female screw 34 but contacts the boundary peripheral edge 36 between the surface of the split key member 31 and the inner peripheral surface of the counterbore 33. For this reason, even if a large load in the steel pipe axis X direction or the circumferential direction is applied to the split key member 31 from the inward groove portion 15 and the outward groove portion 25, the female screw 34 is not damaged, and the hexagon bolt 50 Screwing remains possible. Therefore, the connection of the steel pipe pile P (P1, P2) cannot be released.

  The conical portion 53 in the present embodiment is a reduced diameter portion according to the present invention, and can be inserted into the hole 32 of the split key member 31 and screwed into the female screw 34 when the fixing member 51 is screwed into the through hole 16. The split key member 31 is locked from moving along the circumferential direction.

  As shown in FIG. 5, when the tubular joint 10 and the shaft joint 20 are fitted to each other, the hexagon bolt 50 is removed from the split key member 31, and then fixed as shown in FIG. The member 51 is shallowly screwed into the female screw 18 of the through-hole 16, a tool is fitted into the hole portion 54, and the fixing member 51 is screwed, so that the conical portion 53 becomes the boundary peripheral edge portion 36 as shown in FIG. 7. The split key member 31 is pushed from the storage position to the straddling position. At this time, the split key member 31 is fixed at the straddling position and is also locked to move along the circumferential direction.

  Note that a circumferential groove 17 is formed in the through hole 16 at a location close to the outer peripheral surface of the tubular joint 10. A snap ring 19 for a hole can be attached to the circumferential groove 17. As shown in FIGS. 9 to 11, even if the fixing member 51 is rotated by the snap ring 19 attached to the circumferential groove 17 due to vibration or the like during the embedding operation of the steel pipe pile P (P1, P2), the fixing member 51 Is prevented from falling out of the through-hole 16 and the split key member 31 is maintained in the straddling position, so that there is no possibility that the connection between the tubular joint 10 and the shaft-shaped joint 20 is released.

  The rotation suppression key 40 will be described. As shown in FIG. 1, the rotation suppression key 40 is a member for connecting the cylindrical joint 10 and the shaft-shaped joint 20 in a non-rotating state, and the cylinder-side notch recess 12 and the shaft-side notch recess 22 that face each other. It is comprised in the shape corresponding to the keyway part comprised by these.

  When the cylindrical joint 10 and the shaft-shaped joint 20 are in a state of being fitted to each other, the rotation suppression key 40 is straddled across the cylinder-side notch recess 12 and the shaft-side notch recess 22 (see FIG. 2). By doing so, the relative rotation of the steel pipe piles P (P1, P2) connected to each other is prevented. The rotation suppression key 40 is fixed to the shaft joint 20 by a fixing screw 41.

  In the above-described embodiment, the case where the reduced diameter portion is the conical portion 53 has been described, but the present invention is not limited thereto. The diameter-reduced portion does not need to gradually decrease in diameter from the base end to the tip, and gradually decreases in diameter from the base end to the tip, such as a spherical notch having a spherical crown. May be smaller. In this case, the spherical crown of the ball notch comes into contact with the boundary peripheral edge 36.

  In the above-described embodiment, the case where the hole 32 is provided with the counterbore 33 has been described, but the hole 32 may be provided with a counterbore. FIG. 12 shows an example in which the reduced diameter portion is a spherical notch 55 and the counterbore 37 is provided in the hole 32. In this case, when the tip of the spherical notch 55 is inserted into the hole 32, the spherical crown of the spherical notch 55 and the tapered surface of the counterbore 37 come into contact.

  In the above-described embodiment, the case where the diameter of the reduced diameter portion gradually decreases from the proximal end to the distal end has been described, but the present invention is not limited thereto. The reduced diameter portion may be formed of a small diameter portion whose diameter gradually decreases in the middle from the proximal end to the distal end.

  In FIG. 13, the reduced diameter portion is the small diameter portion 56, and the outer peripheral surface of the small diameter portion 56 and the inner peripheral surface of the spot facing 33 come into contact when the tip of the small diameter portion 56 is inserted into the hole portion 32. Show. The hole 32 may be provided with a counterbore 37 as shown in FIG. 12 instead of the counterbore 33. In this case, when the distal end of the small diameter portion 56 is inserted into the hole portion 32, the peripheral edge portion of the distal end of the small diameter portion 56 and the tapered surface of the counterbore 37 are in contact with each other.

  In the above-described embodiment, the case where the holding member is the hexagon bolt 50 has been described, but the holding member is not limited to the hexagon bolt 50. For example, as shown in FIG. 14, the holding member may be a so-called very low-head hexagon socket head bolt 60 having a lower head than a normal bolt. In FIG. 14, the same components as those in FIG. 3 are denoted by the same reference numerals.

  At this time, the diameter of the head of the ultra low-head hexagon socket head cap screw 60 is larger than the inner diameter of the portion of the through hole 16 where the female screw 18 is formed, and the peripheral groove 17 of the through hole 16 is formed. The inner diameter of the portion of the through-hole 16 where the female screw 18 is formed is set smaller than the diameter of the head of the ultra-low head hexagon socket head cap screw 60, By setting the inner diameter of the portion of the through-hole 16 where the circumferential groove 17 is formed to be larger than the diameter of the head of the ultra-low head hexagon socket head cap screw 60, the ultra-low head screwed into the split key member 31 is set. The head of the hexagon socket head bolt 60 contacts the boundary between the portion of the through hole 16 where the female screw 18 is formed and the portion of the through hole 16 where the circumferential groove 17 is formed.

  When the split key member 31 is disposed in the inward groove portion 15 so that the hole portion 32 faces the through hole 16, the very low head hexagon socket head bolt 60 is loosely inserted into the through hole 16, and the split key The split key member 31 can be held in the storage position by being screwed into the female screw 34 of the member 31.

  At this time, the very low head hexagon socket head cap screw 60 uses a shaft having an appropriate length and an appropriate height in which the head fits in the through hole 16, in other words, the cylindrical joint 10. When the depth from the surface to the portion of the through-hole 16 where the circumferential groove 17 is formed is set deeper than the height of the head, when screwed into the female screw 34 of the split key member 31, The head does not protrude outward from the surface of the cylindrical joint 10.

  Further, the holding member may be a hexagon socket countersunk bolt 70 as shown in FIG. In FIG. 15, the same components as those in FIG. 3 are denoted by the same reference numerals.

  At this time, the diameter of the head of the countersunk bolt 70 with a hexagonal hole is larger than the inner diameter of the portion of the through hole 16 where the female screw 18 is formed, and the portion of the through hole 16 where the circumferential groove 17 is formed. The inner diameter of the portion of the through hole 16 where the female screw 18 is formed is set smaller than the diameter of the head of the hexagon socket countersunk bolt 70, and The head of the hexagon socket countersunk bolt 70 screwed into the split key member 31 is set by setting the inner diameter of the portion where the circumferential groove 17 is formed larger than the diameter of the head of the hexagon socket countersunk bolt 70. However, it contacts the boundary portion between the portion of the through hole 16 where the female screw 18 is formed and the portion of the through hole 16 where the circumferential groove 17 is formed.

  When the split key member 31 is disposed in the inward groove portion 15 so that the hole portion 32 faces the through hole 16, the hexagon socket countersunk bolt 70 is loosely inserted into the through hole 16, and the split key member 31 is inserted. The split key member 31 can be held in the storage position by being screwed into the female screw 34.

  At this time, the hexagon socket countersunk bolt 70 has an appropriate length at its shaft portion and an appropriate height at which the head portion can be accommodated in the through hole 16, in other words, the cylindrical joint 10. By setting the depth from the surface of the through hole 16 to the portion of the through-hole 16 where the circumferential groove 17 is formed, the depth is set deeper than the height of the portion of the head that is larger than the inner diameter of the female screw 18. When screwed into the female thread 34 of the member 31, the head does not protrude outward from the surface of the cylindrical joint 10.

  In the above-described embodiment, the case where the hole portion 32 penetrating in the thickness direction at the center position in the longitudinal direction and the height direction of the split key member 31 is constituted by the counterbore 33 and the female screw 34 has been described. However, it is not limited to this. The hole 32 may be constituted only by the female screw 34, or may be constituted by a simple depression or a through hole in which the female screw is not formed.

  In the above-described embodiment, the case where the holding member that holds the split key member 31 in the storage position is the hexagon bolt 50 has been described, but the present invention is not limited thereto. The holding member may be composed of a dimensioning bolt that is screwed to the female screw 34 of the split key member 31 and a nut that is threaded to the dimensioning bolt from the outside of the through hole 16. In this case, the split key member 31 is extended from the accommodation position from the outer peripheral surface side of the cylindrical joint by loosening or removing the nut from the other end while one end of the cutting bolt is screwed to the split key member 31. It becomes possible to push in to the position.

[Other Embodiments]
1. Even if the steel pipe coupling mechanism J according to the present invention is configured to be capable of being pushed from the outer peripheral side of the tubular joint 10 into the straddling position by pushing the split key member 31 at the accommodation position with an appropriate rod or the like through the through hole 16. Good.
2. The steel pipe coupling mechanism J according to the present invention may be provided with a fixing means capable of fixing the split key member 31 in the straddling position with a plug or the like screwed into the through-hole 16 so as to be unlocked.
3. The steel pipe piles P (P1, P2) connected by the steel pipe connection mechanism J according to the present invention include building support piles, landslide prevention piles, column piles for earth retaining such as steel pipe sheet piles, partition walls, revetment walls, and structures. Can be used for various purposes such as pillars, etc., in addition to the medium digging method, a driving method that is performed by striking, a pre-boring method that is inserted into an existing digging hole, or a soil that is embedded while rotating through the formation of soil cement It can be laid using a cement synthetic pile method or a rotary buried pile method that is simply rotated and press-fitted (buried). When the steel pipe is driven by a method that does not involve rotation, the steel pipe coupling mechanism may not include the rotation suppression key 40.
4). The steel pipe coupling mechanism J according to the present invention may be provided with a tubular joint 10 or a shaft-like joint 20 at a pipe end such as a UO pipe, a bending pipe, or a cast steel pipe cast by a centrifugal casting method.

  Each of the above-described embodiments is an example of the present invention, and the present invention is not limited by the description. The specific configuration of each part can be appropriately changed and designed within the range where the effects of the present invention are exhibited. is there.

10: Cylindrical joint 13: Inner peripheral surface (inner peripheral surface of cylindrical joint)
15: Inward groove 16: Through hole 18: Female screw 20: Shaft joint 23: Outer peripheral surface (outer peripheral surface of the shaft joint)
25: outward groove 26: female screw 30: load transmission key (key member)
31: Split key member (key member)
32: Hole 33: Counterbore 34: Female screw 37: Counterbore 50: Hex bolt (holding member)
51: Fixing member 52: Male screw 53: Conical part (reduced diameter part)
55: Sphere missing part (reduced diameter part)
56: Small diameter part (reduced diameter part)
60: Extremely low head hexagon socket head cap screw (holding member)
70: Hexagon socket countersunk bolt (holding member)
J: Steel pipe coupling mechanism P: Steel pipe pile S: Steel pipe X: Steel pipe axis

Claims (7)

A tubular joint provided at one of the steel pipe end portions facing each other of the steel pipes adjacent to each other in the axial direction of the steel pipe, and a shaft joint provided at the other steel pipe end portion and engageable with the tubular joint;
An accommodation position where the cylindrical joint inner peripheral surface of the cylindrical joint enters the inward groove provided along the circumferential direction from the inner peripheral surface of the cylindrical joint;
When the cylindrical joint and the shaft-shaped joint are fitted to each other, an outer surface provided on the outer surface of the shaft-shaped joint of the shaft-shaped joint so as to face the inward groove portion along the circumferential direction. A steel pipe coupling mechanism having a key member that is arranged so that a position change is possible at a straddling position straddling the facing groove portion and the inward groove portion,
The cylindrical joint is provided with a through hole communicating from the outer surface of the cylindrical joint into the inward groove portion,
The key member is provided with a hole facing the through hole,
A fixing member can be attached to the through hole,
On one end side of the fixing member, a base end connected to the one end side is larger than a diameter of the hole portion, and a distal end is provided with a reduced diameter portion smaller than the diameter of the hole portion,
The said fixing member is a steel pipe connection mechanism which can fix the said key member to the said straddling position by contacting the said hole part between the front-end | tip of the said diameter reduction part.   2. The steel pipe coupling mechanism according to claim 1, wherein the diameter-reduced portion gradually decreases in diameter from the base end to the tip at a constant rate.   2. The steel pipe coupling mechanism according to claim 1, wherein the diameter-reduced portion gradually decreases in diameter from the proximal end to the distal end at a different rate.   The steel pipe coupling mechanism according to claim 1, wherein the diameter of the reduced diameter portion gradually decreases in the middle from the base end to the tip end. A female screw is provided on the inner peripheral surface of the through hole,
The steel pipe coupling mechanism according to any one of claims 1 to 4, wherein a male screw that can be screwed into the female screw is provided on the other end side of the fixing member. The hole includes a counterbore, and a female screw to which a holding member that holds the key member in the accommodation position through the through hole from the outer peripheral side of the cylindrical joint can be screwed.
The steel pipe coupling mechanism according to any one of claims 1 to 5, wherein the reduced diameter portion is in contact with the counterbore. The hole is provided with a countersink and a female screw to which a holding member for holding the key member in the storage position through the through hole from the outer peripheral side of the cylindrical joint can be screwed.
The steel pipe coupling mechanism according to any one of claims 1 to 5, wherein the reduced diameter portion is in contact with the counterbore.

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