JP2024027275A - Steel pipe connection device - Google Patents

Abstract

An object of the present invention is to provide a steel pipe connecting device that allows easy connecting work and high work efficiency. [Solution] A box joint 1 and a pin joint 2 provided at mutually opposing ends of a steel pipe, and a key that straddles the boundary between these joints 1 and 2 formed by fitting these joints 1 and 2 together. The key 3 is housed in the groove 31 and is movable to a straddling position straddling the boundary between the joints 1 and 2, and a pin 4 having a shaft portion 41 and a head 42. A through hole 16 and a hole 26 communicating with the keyway 31 are formed in the joints 1 and 2, respectively, and a through hole 32 opposite to the through hole 16 and the hole 26 is formed in the key 3. When the pin 4 is placed in the set position where the shaft 41 is inserted into the through hole 32 and the hole 26 and the head 42 is inserted into the through hole 16, the key 3 is positioned at the straddling position by the head 42. be done. [Selection diagram] Figure 7

Description

The present invention relates to a steel pipe connecting device used for connecting steel pipes constituting a steel pipe pile.

The above-mentioned steel pipe coupling device is provided on the inner circumferential surface of the cylindrical part, with the cylindrical part welded to one end of the steel pipe and the shaft part welded to the other end of the steel pipe fitted together. There has been known a structure in which an arcuate key is disposed at a position straddling a groove provided on the outer circumferential surface of the shaft, and thereby the steel pipes are connected in a state where they are prevented from coming off (Patent Document 1).

Japanese Patent Application Publication No. 2000-319874

The steel pipe coupling device of Patent Document 1 is provided with means for preventing relative rotation between the coupled steel pipes. Specifically, by fitting a rotation inhibiting key into a notched recess formed so as to straddle the outer circumferential surfaces of the cylinder part and the shaft part that are fitted together, the relative rotation of the cylinder part and the shaft part is restrained. This allows the steel pipes to be connected in a non-rotating manner.

However, in the steel pipe connecting device with the above configuration, it is necessary to fix the rotation suppression key with bolts or the like so that it does not fall out of the notch recess, so there is a problem that the work of connecting the steel pipes is time-consuming and work efficiency is low. Ta.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a steel pipe connecting device that allows easy connecting work and high work efficiency.

A steel pipe coupling device according to the present invention for achieving the above-mentioned object is provided at one of the mutually opposing steel pipe ends of adjacent steel pipes in the axial direction of the steel pipes, and has an inner circumferential surface facing inward along the circumferential direction. A box joint in which a groove is formed, and an outward groove provided on the other end of the steel pipe and facing the inward groove when the box joint and the box joint are fitted together extend along the circumferential direction on the outer peripheral surface. a load transmission key whose position can be changed between a storage position stored in the inward groove and a straddling position spanning the outward groove and the inward groove; and a shaft. and a pin having a head connected to one end of the shaft part, the box joint having a box joint that communicates from the bottom of the inward groove to the outer circumferential surface of the box joint. A through hole is formed in the pin joint, and when the box joint and the pin joint are fitted together, a pin joint hole portion facing the box joint through hole extends from the bottom of the outward groove portion to the pin joint. The pin is formed to extend toward an inner peripheral surface of the joint, and the shaft portion of the pin is inserted into the pin joint hole from the outer peripheral surface of the box joint, and the head is inserted into the box joint through hole. and the load transmission key is configured to be positioned in the straddling position by contact with the head when the pin is placed in the set position. It is characterized by

In the steel pipe coupling device with the above configuration, when the pin is placed in the set position with the box joint and pin joint fitted together, the box joint and pin joint tend to rotate relative to each other due to the application of rotational force. Also, since the walls of the box joint through hole and the pin that straddle the pin joint hole abut from opposite directions, the relative rotation of the box joint and pin joint is suppressed. That is, according to the steel pipe connecting device configured as described above, by performing the step of inserting the pin, the box joint and pin joint that are fitted together can be moved from a relatively rotatable state to a rotation-preventing state.

On the other hand, the conventional steel pipe coupling device as shown in Patent Document 1 requires at least a step of fitting a rotation prevention key into a notch recess in order to shift a box joint and a pin joint that are fitted together to a non-rotating state. , it is necessary to perform the steps of fixing the rotation prevention key with bolts. As described above, compared to the conventional steel pipe coupling device, the steel pipe coupling device of the present invention simplifies the process for coupling steel pipes, and thus improves the efficiency of the coupling operation.

Furthermore, in the steel pipe coupling device having the above configuration, the load transmission key is positioned at the straddling position during the process of inserting the pin, so that the box joint and the pin joint are prevented from coming off. That is, according to the steel pipe connecting device configured as described above, by performing the step of inserting the pin, the box joint and pin joint that are fitted together can be moved from a separable state to a locking state.

On the other hand, in conventional steel pipe coupling devices, it is necessary to separately perform a process for transitioning to the rotation prevention state and a process for transitioning to the slippage prevention state. As described above, compared to the conventional steel pipe coupling apparatus, the steel pipe coupling apparatus of the present invention simplifies the process of coupling steel pipes, and thus improves the efficiency of the coupling operation.

In the steel pipe coupling device according to the present invention, the load transmission key is formed with a key through hole that faces the box joint through hole and the pin joint hole when the box joint and the pin joint are fitted together. and when the pin is placed at the set position, the shaft passes through the key through hole and is inserted into the pin joint hole, and the head abuts around the key through hole and It is preferable to position the load transmission key at the straddling position.

Although a plurality of load transmission keys are usually provided, it is preferable to position these load transmission keys in a straddling position with equal intervals in the circumferential direction so that the load is evenly applied. According to the steel pipe coupling device having the above configuration, since the shaft portion passes through the key through hole when the pin is placed in the set position, circumferential displacement of the load transmission key with respect to the pin is unlikely to occur. That is, it becomes easy to position the load transmission keys in the straddling position at desired intervals.

In the steel pipe connecting device according to the present invention, it is preferable that the head of the pin has a tapered portion that gradually reduces in diameter in the direction of the shaft at one end connected to the shaft.

A bending moment acts on the pin that suppresses the relative rotation of box joints and pin joints, but stress is concentrated at the connection point between the pin head and shaft due to changes in the cross-sectional shape. Easier to destroy. According to the steel pipe connecting device configured as described above, the change in cross-sectional shape at the connection point between the head of the pin and the shaft portion becomes gentler, so that stress concentration is alleviated and breakage becomes less likely to occur.

In the steel pipe coupling device according to the present invention, the load transmission key has a recess on the outer circumferential surface of the box joint that has a shape complementary to the tapered portion and receives at least a portion of the tapered portion. suitable.

According to the steel pipe connecting device having the above configuration, when the pin is placed at the set position, the load transmission key is positioned at the straddling position by abutting the tapered portion of the head of the pin with the recessed portion. Compared to the case where no recess is formed in the load transmission key, the load transmission key comes into contact with the head of the pin over a wider area, so it is possible to reduce the force per unit area that acts on the contact area. As a result, damage to the contact area can be prevented.

The steel pipe coupling device according to the present invention further includes a stop ring that restricts movement of the pin placed at the set position toward the outer peripheral surface of the box joint, the stop ring being formed in the box joint through hole. It is preferable that it be installed in a designated mounting groove.

According to the steel pipe coupling device having the above configuration, it is possible to prevent the steel pipes from being uncoupled due to the pin placed at the set position accidentally coming off toward the outer peripheral surface of the box joint.

The steel pipe connecting device according to the present invention is suitable for use in connecting steel pipes forming a steel pipe pile in a method of press-fitting a steel pipe pile into the ground without applying rotational force.

If the method involves press-fitting steel pipe piles into the ground without applying rotational force, the rotational force transmitted between the steel pipes during burying the steel pipe piles will be reduced or eliminated, which will prevent relative rotation between the steel pipes. It becomes possible to use pins with lower strength or to reduce the number of pins installed. When the number of installations is reduced, the time and effort required for connection work is reduced, which further improves work efficiency. Furthermore, the cost of pins can be reduced both when using lower strength pins and when reducing the number of pins installed.

It is a partial cross-sectional view of a steel pipe pile constructed by connecting steel pipes by a steel pipe connection mechanism. It is a figure explaining the process of fitting a box joint into a pin joint. FIG. 6 is a diagram showing the load transfer key held in a retracted position. It is a figure explaining the process of releasing the hold|maintenance of a load transmission key. It is a figure explaining the process of arranging a pin to a set position. It is a figure explaining the process of attaching a stop ring to the pin arrange|positioned at a set position. It is a figure which shows the state where the relative rotation of a box joint and a pin joint is suppressed by the pin. FIG. 7 is a diagram showing a pin and a load transmission key of another embodiment. It is a figure showing the steel pipe connection mechanism of other embodiments. It is a figure which shows the pin of other embodiments. FIG. 7 is a diagram showing the state of the pin of a further embodiment before rotation; FIG. 12 is a diagram showing the rotation of the pin of the embodiment shown in FIG. 11; FIG. 12 is a diagram showing the state of the pin of the embodiment shown in FIG. 11 after rotation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a steel pipe coupling device according to the present invention will be described with reference to the drawings.

The steel pipe connecting device J is for constructing a steel pipe pile P by connecting mutually opposing ends of steel pipes S1 and S2 that are adjacent to each other in the steel pipe axial direction X (in this embodiment, the same direction as the vertical direction). It includes a box joint 1, a pin joint 2, a load transmission key 3, a pin 4, and a stop ring 5 (see FIGS. 1, 2, and 6).

[Box joint]
The box joint 1 is created by processing a steel cylindrical body. The upper end of the box joint 1 is connected to the end of the steel pipe S1 by welding or the like. As shown in FIG. 2, the box joint 1 is provided with a protrusion 11 at the lower end, and a circumferential groove 13 is formed near the upper end of the inner circumferential surface 12.

Further, as shown in FIGS. 2 and 3, two inward grooves 14 are formed along the circumferential direction on the inner circumferential surface 12 of the box joint 1, although the invention is not limited thereto. Each inward groove 14 is configured to be deeper than the thickness along the radial direction of the steel pipe pile P of the load transmission key 3, which will be described later, and higher than the height along the steel pipe axial direction X of the load transmission key 3. .

Furthermore, as shown in FIGS. 1 to 3, the box joint 1 has a box joint through hole 16 with a circular cross section that communicates from the bottom of the inward groove 14 to the outer circumferential surface 15 of the box joint 1. A plurality of them are provided at equal intervals in the circumferential direction, corresponding to the installation locations. A mounting groove 17 for mounting a stop ring 5, which will be described later, is provided around the box joint through hole 16 near the outer circumferential surface 15 of the box joint 1.

[Pin joint]
The pin joint 2 is created by processing a steel cylindrical body, and has a shape that allows at least a portion of the pin joint 2 in the axial direction to be inserted into the box joint 1. The outer peripheral surface 21 of the portion that can be inserted into the box joint 1 is formed to have a substantially smaller diameter than the inner peripheral surface 12 of the box joint 1.

The lower end of the pin joint 2 is connected to the end of the steel pipe S2 by welding or the like. As shown in FIG. 2, when the pin joint 2 is inserted into the box joint 1, a protrusion 22 that can fit into the circumferential groove 13 of the box joint 1 is provided at the upper end. A circumferential groove 23 into which the protrusion 11 provided can fit is formed near the lower end of the outer circumferential surface 21. By fitting the protrusions 22 and 11 into the circumferential grooves 13 and 23, respectively, the box joint 1 and the pin joint 2 can be separated along the steel pipe axial direction Fitted.

Further, as shown in FIGS. 2, 3, and 6, two outward grooves 24 are formed along the circumferential direction on the outer peripheral surface 21 of the pin joint 2, although not limited thereto. and are formed so as to face the inward groove 14 when they are fitted together. Each outward groove 24 is configured to be shallower than the thickness of the load transmission key 3 (described later) (approximately half the thickness in this embodiment), and has a height higher than that of either the load transmission key 3 or the inward groove 14. It is also highly structured. When the box joint 1 and the pin joint 2 are fitted together, the lower side wall surface of the outward groove 24 is at approximately the same height as the lower side wall surface of the inward groove 14; The upper side wall surface of the facing groove part 24 is located at a higher position than the upper side wall surface of the inward facing groove part 14. The inward groove portion 14 and the outward groove portion 24 facing each other constitute a key groove 31 for accommodating the load transmission key 3.

Furthermore, the pin joint 2 has a pin joint hole 26 with a circular cross section extending from the bottom of the outward groove 24 toward the inner circumferential surface 25 of the pin joint 2, corresponding to the installation location of the load transmission key 3, which will be described later. , a plurality of them are provided at equal intervals in the circumferential direction. The pin joint hole portion 26 has a smaller diameter than the box joint through hole 16, and is configured to face the box joint through hole 16 via the keyway 31 when the box joint 1 and pin joint 2 are fitted together. It is set in. In this embodiment, the pin joint hole 26 is a through hole that communicates from the bottom of the outward groove 24 to the inner peripheral surface 25. However, the pin joint hole 26 may be a blind hole that does not communicate to the inner peripheral surface 25.

[Load transmission key]
The load transmission key 3 is a member for connecting the box joint 1 and the pin joint 2 in a secure manner when the box joint 1 and the pin joint 2 are fitted to each other. As shown in FIGS. 2 and 3, the load transmission key 3 is composed of an arc-shaped steel member having a rectangular cross section. Load transmission keys 3 are arranged around the steel pipe axis X at intervals. Therefore, eight box joint through-holes 16 of the box joint 1 and eight pin joint holes 26 of the pin joint 2 are provided so as to correspond to the number of load transmission keys 3.

A key through hole 32 that penetrates the load transmission key 3 in the thickness direction is bored at the center position of the load transmission key 3 in the longitudinal direction and the height direction. The key through hole 32 has a female threaded portion 321 located on the outer peripheral surface 15 side of the box joint 1 and a non-threaded portion 322 located on the inner peripheral surface 25 side of the pin joint 2. When the box joint 1 and the pin joint 2 are fitted together, the female threaded portion 321 faces the box joint through hole 16, and the non-threaded portion 322 faces the pin joint hole 26. The female threaded portion 321 has a smaller diameter than the box joint through hole 16, and the non-threaded portion 322 has a smaller diameter than the female threaded portion 321 and the pin joint hole 26.

In the key groove 31, the load transmission key 3 is placed in a stored position where the entire thickness thereof is inside the inward groove 14 (see FIGS. 2 and 3), and in a straddle position where it straddles the inward groove 14 and the outward groove 24. The position can be changed between the installed position (see Figures 6 and 7). When the load transmission key 3 is placed in the straddling position, the box joint 1 and the pin joint 2, which are loosely fitted, are connected in a manner that prevents them from coming off.

〔pin〕
As shown in FIGS. 6 and 7, the pin 4 is a steel member having a long shaft portion 41 having a substantially circular cross section and a head portion 42 connected to one end of the shaft portion 41. As shown in FIGS. An end surface 421 of the head 42 connected to the shaft 41 is substantially perpendicular to the longitudinal direction of the shaft 41 . The shaft portion 41 is formed to have a substantially smaller diameter than the pin joint hole portion 26 and the non-threaded portion 322 of the key through hole 32, and to be longer than the length of the key through hole 32. On the other hand, the head 42 is formed to have a larger diameter than the key through hole 32 and a substantially smaller diameter than the box joint through hole 16, and the length of the head 42 and the thickness of the load transmission key 3 The sum of the depths of the inward grooves 14 and the outward grooves 24 is greater than the sum of the depths of the inward grooves 14 and the outward grooves 24.

When the pin 4 formed in this manner is inserted into the box joint through hole 16 from the outer peripheral surface 15 of the box joint 1, the load transmission key 3 is pushed to the bottom of the outward groove 24 by contact with the end surface 421 of the head 42. It is pushed in and positioned in the straddling position. Further, the shaft portion 41 is inserted through the key through hole 32 to the pin joint hole portion 26, and the head portion 42 is held at least a portion of the outer peripheral surface 15 side of the box joint 1 within the box joint through hole 16. be done. Note that the position of the pin 4 at this time corresponds to the set position according to the present invention.

When the pin 4 is placed in the set position, the load transmission key 3 is positioned in the straddling position, thereby connecting the box joint 1 and the pin joint 2 in a manner that prevents them from coming off. Further, when the box joint 1 attempts to rotate relative to the pin joint 2 by applying a counterclockwise rotational force as shown in FIG. 7 as an example, the box joint through-hole 16 and The walls of these through holes 16 and 26 abut against the pin 4 that straddles the pin joint hole 26 from the opposite direction (in the form shown in FIG. (The wall portion contacts the shaft portion 41 from the counterclockwise direction, and the wall portion of the pin joint hole 26 contacts the shaft portion 41 from the clockwise direction.) Therefore, the rotational force acting on the box joint 1 causes the pin 4 to This is transmitted to the pin joint 2 via the box joint 1 and the pin joint 2, thereby suppressing relative rotation between the box joint 1 and the pin joint 2. As a result, the box joint 1 and the pin joint 2 are connected in a non-rotating state.

As shown in FIG. 6, before a tensile load is applied to the steel pipe pile P, the distance between the upper side wall surface of the outward groove 24 and the upper side surface of the load transmission key 3 is the same as that of the shaft of the pin 4. 41 and the upper side wall surface of the pin joint hole 26. As a result, when a tensile load is applied to the steel pipe pile P, the load transmission key 3 rises together with the box joint 1 and eventually comes into contact with the upper side wall surface of the outward groove 24, but even at this time, the pin 4 Since the shaft portion 41 does not come into contact with the upper side wall surface of the pin joint hole portion 26, the tensile load is transmitted only by the load transmission key 3. This can prevent the shaft portion 41 of the pin 4, which has lower strength than the load transmission key 3, from breaking due to tensile load.

[Stop ring]
As shown in FIGS. 6 and 7, the stop ring 5 can be attached to the attachment groove 17 by reducing its diameter using an attachment jig. By attaching the stop ring 5 to the mounting groove 17 formed on the outer circumferential surface 15 side of the box joint 1 than the head 42 of the pin 4 placed at the set position, the pin 4 can be attached to the outer circumferential surface 15 side of the box joint 1. Since the movement of the box joint 1 and the pin joint 2 is restricted, there is no risk that the pin 4 will move away from the set position due to vibration or the like and the connection between the box joint 1 and the pin joint 2 will be released.

<Steel pipe connection method>
Hereinafter, a method for connecting the steel pipes S1 and S2 using the steel pipe connecting device J according to the present invention configured as described above will be described. Note that a description of the process of connecting the box joint 1 and the pin joint 2 to the ends of the steel pipes S1 and S2 is omitted.

First, as shown in FIGS. 2 and 3, the box joint 1 is moved above the pin joint 2 using a crane or the like. Inside the inward groove 14 of the box joint 1, a bolt is inserted into the box joint through hole 16 from the outer peripheral surface 15 side of the box joint 1 and screwed into the female thread 321 in the key through hole 32 of the load transmission key 3. 6, each load transmission key 3 is held in the storage position in advance.

Next, the steel pipe S1 is lowered and the box joint 1 and pin joint 2 are loosely fitted. Note that when lowering the steel pipe S1, the steel pipe S1 is appropriately rotated so that the key through hole 32 of the load transmission key 3 is generally opposed to the pin joint hole portion 26 of the pin joint 2.

Then, as shown in FIG. 4, the bolt 6 is removed from the box joint 1, and the load transmission key 3 is no longer held by the bolt 6.

Thereafter, as shown in FIG. 5, the pin 4 is inserted through the box joint through hole 16 and placed in the set position, thereby bringing the box joint 1 and pin joint 2, which are in the loosely fitted state, into the non-removal state and the non-rotating state. Connect with.

Furthermore, as shown in FIG. 6, the stop ring 5 is attached to the mounting groove 17 to hold the pin 4 in the set position. Through the above steps, the steel pipe S1 and the steel pipe S2 are connected.

Note that when dividing the steel pipes S1 and S2, the above steps may be performed in the reverse order. Specifically, first, the stop ring 5 is removed from the mounting groove 17. Next, a tool such as a hex wrench is fitted into the hole 422 formed in the head 42 of the pin 4, and the pin 4 is removed from the box joint through hole 16. Then, the bolt 6 is inserted through the box joint through hole 16 and screwed into the key through hole 32 of the load transmission key 3, and the load transmission key 3 is pulled back to the storage position. As a result, the box joint 1 and the pin joint 2 become loosely fitted, so that the steel pipe S1 and the steel pipe S2 can be separated.

Methods for burying steel pipes include the driving method, pre-boring method, hollow digging method, and rotating buried pile method. A steel pipe pile constructed using the steel pipe coupling device J according to the present invention can be used regardless of the construction method, but can preferably be used in a construction method that does not apply rotational force to the steel pipe pile, such as a driving method. In the case of this construction method, the rotational force acting on the pin 4 during burying of the steel pipe pile P is reduced or eliminated, so the possibility that the pin 4 will break is reduced. However, by using stronger pins 4 or increasing the number of pins 4, it becomes possible to transmit rotational force without worrying about breakage, so it is used in construction methods that apply rotational force. The steel pipe connection device J according to the present invention may be used to construct the steel pipe pile P.

<Other embodiments>
(1) In the steel pipe connecting device J of the embodiment described above, the head 42 of the pin 4 is formed such that the end surface 421 connected to the shaft portion 41 is approximately perpendicular to the longitudinal direction of the shaft portion 41. . However, the present invention is not limited thereto. As shown in FIG. 8, the head portion 42 of the pin 4 may have a tapered portion 423 at one end connected to the shaft portion 41, the diameter of which gradually decreases in the direction of the shaft portion 41. Correspondingly, the load transmission key 3 has a recess 33 formed on the surface of the box joint 1 on the outer circumferential surface 15 side, having a shape complementary to the tapered part 423 and receiving a part of the tapered part 423. It may have. In this embodiment, the pin 4 positions the load transmission key 3 at the straddling position by bringing the tapered portion 423 into contact with the recess 33 . Note that the recessed portion 33 may be formed to receive the entire tapered portion 423.

(2) In the steel pipe coupling device J of the embodiment described above, the shaft portion 41 of the pin 4 passes through the key through hole 32 and is inserted up to the pin joint hole portion 26, and the head 42 abuts around the key through hole 32. It is configured so that it can be placed in a set position in which the load transmission key 3 is positioned in contact with the straddle position. However, the steel pipe coupling device J of the present invention is not limited to this. As shown in FIG. 9, the box joint through hole 16' and the pin joint hole are arranged so as to face the gap between the adjacent ends 34 of the load transmission keys 3, which are arranged with a gap around the steel pipe axis X. 26' is provided, the pin 4 is inserted into the pin joint hole 26' with the shaft portion 41 passing through the gap between the end portions 34, and the head portion 42 abutting the end portions 34 to connect the load transmission key 3. It may also be configured such that it can be placed in a set position where it is positioned in a straddling position. Also in the steel pipe coupling device of this embodiment, steel pipes can be coupled or divided by performing the same steps as the steel pipe coupling device J of the embodiment described above. In this embodiment as well, it is necessary to provide a through hole 18 in the box joint 1 through which the bolt 6 is inserted, but the through hole 18 can have a diameter substantially larger than the outer diameter of the bolt 6.

(3) In the steel pipe coupling device J of the embodiment described above, the pin 4 is held in the set position by the stop ring 5, but there is no means for restricting the movement of the pin 4 toward the outer circumferential surface 15 of the box joint 1. It is not limited to this.
For example, by forming the box joint through hole 16 as a female threaded hole and forming the head 42 of the pin 4 as a male thread, the friction that occurs between the box joint through hole 16 and the head 42 that are screwed together. The movement of the pin 4 can also be restricted by force.
Alternatively, as shown in FIG. 10, a so-called drop-off prevention bolt is used as the pin 4, in which a male screw portion 411 is provided only on the tip side of the shaft portion 41, and a threaded finish is applied to the head portion 42 side of the shaft portion 41. In addition, the pin joint hole 26 may be formed into a female threaded hole. In this case, the pin 4 is placed at the set position so that the male threaded portion 411 on the tip side of the shaft portion 41 screws through the pin joint hole 26 and penetrates to the inner circumferential surface 25 side of the pin joint 2. However, the pin 4 arranged in this manner is restricted from moving toward the outer circumferential surface 15 of the box joint 1 because the male threaded portion 411 of the pin 4 is caught in the female threaded portion of the pin joint hole 26. .
Furthermore, as shown in FIGS. 11 to 13 (for convenience of explanation, the pin 4 is shown in a non-sectional view), a protrusion extending in the axial direction of the pin 4 is provided on the outer peripheral surface of the head 42 of the pin 4 on the shaft portion 41 side. Two portions 424 may be provided at equal intervals in the circumferential direction, and a groove portion 161 for slidingly guiding the projection portion 424 of the head portion 42 may be provided in the box joint through hole 16. Here, the protrusion 424 is configured to pass through the groove 161 of the box joint through hole 16 and be accommodated in the inward groove 14 when the pin 4 is inserted to the set position. In this case, when installing the pin 4, the pin 4 is inserted into the set position with the projection 424 of the head 42 guided by the groove 161 of the box joint through hole 16. After the protrusion 424 of 42 passes through the groove 161 and moves to the inward groove 14 (see FIG. 11), the pin 4 is rotated by a predetermined angle (for example, 90 degrees) so that the protrusion 424 does not face the groove 161. 12 and 13), the movement of the pin 4 toward the outer circumferential surface 15 of the box joint 1 will cause the protrusion 424 to be formed at the bottom of the inward groove 14 (the area indicated by the two-dot chain line in FIG. 13). It is regulated by the contact between the two. Note that the number of protrusions 424 is not limited to two, and may be one, or three or more.

1: Box joint 2: Pin joint 3: Load transmission key 4: Pin 5: Stop ring 6: Bolt 11: Projection 12: Inner peripheral surface 13: Circumferential groove 14: Inward groove 15: Outer peripheral surface 16, 16': Box joint through hole 161: Groove 17: Mounting groove 18: Through hole 21: Outer circumferential surface 22: Projection 23: Circumferential groove 24: Outward groove 25: Inner circumferential surface 26, 26': Pin joint hole 31: Key groove 32 : Key through hole 321 : Female threaded part 322 : Unthreaded part 33 : Recessed part 34 : End part 41 : Shaft part 411 : Male threaded part 42 : Head 421 : End surface 422 : Hole part 423 : Tapered part 424 : Projection part J: Steel pipe coupling device P: Steel pipe pile S1: Steel pipe S2: Steel pipe X: Steel pipe axial direction

Claims (6)

a box joint that is provided on one of the opposing ends of steel pipes that are adjacent to each other in the axial direction of the steel pipes, and has an inward groove formed in the inner circumferential surface along the circumferential direction;
a pin joint that is provided at the other end of the steel pipe and has an outward groove formed along the circumferential direction on the outer circumferential surface thereof, and which faces the inward groove when the box joint and the box joint are fitted together;
a load transmission key whose position can be changed between a storage position stored in the inward groove and a straddling position spanning the outward groove and the inward groove;
A steel pipe connecting device comprising a shaft portion and a pin having a head connected to one end of the shaft portion,
A box joint through hole is formed in the box joint, which communicates from the bottom of the inward groove to the outer peripheral surface of the box joint,
In the pin joint, when the box joint and the pin joint are fitted together, a pin joint hole portion that faces the box joint through hole extends from the bottom of the outward groove to the inner circumferential surface of the pin joint. It is formed so as to extend toward the
The pin can be placed in a set position where the shaft portion is inserted into the pin joint hole from the outer peripheral surface of the box joint and the head is inserted into the box joint through hole,
The load transmission key is configured to be positioned at the straddling position by contact with the head when the pin is placed at the set position. The load transmission key is formed with a key through hole that faces the box joint through hole and the pin joint hole when the box joint and the pin joint are fitted together,
When the pin is placed in the set position,
The shaft portion passes through the key through hole and is inserted into the pin joint hole portion,
The steel pipe connecting device according to claim 1, wherein the head abuts around the key through hole to position the load transmission key at the straddling position. 3. The steel pipe connecting device according to claim 2, wherein the head of the pin has a tapered portion that gradually reduces in diameter in the direction of the shaft at one end connected to the shaft. The steel pipe coupling device according to claim 3, wherein the load transmission key has a recessed portion on a surface on the outer peripheral side of the box joint, the recessed portion having a shape complementary to the tapered portion and receiving at least a portion of the tapered portion. . further comprising a stop ring that restricts movement of the pin placed at the set position toward the outer peripheral surface of the box joint;
The steel pipe coupling device according to any one of claims 1 to 4, wherein the stop ring is attached to a mounting groove formed in the box joint through hole. The steel pipe connecting device according to any one of claims 1 to 4, which is used for connecting steel pipes constituting a steel pipe pile in a method of press-fitting a steel pipe pile into the ground without applying rotational force.

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