JP2018003431A - Screw joint having inverse rotation prevention mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw joint having an inverse rotation prevention mechanism, without enlarging the screw joint, and without causing useless rotation in inverse rotation time.SOLUTION: A screw joint 1 having an inverse rotation prevention mechanism on the present invention, is a connection joint of a steel pipe composed of a screw type male joint 3 and a female joint 5 and joining the steel pipe 7 by being installed in an end part of the steel pipe 7, and comprises the inverse rotation prevention mechanism 9 for preventing inverse rotation of the male joint 3 and the female joint 5 in a fitting completion state, and the inverse rotation prevention mechanism 9 comprises a key groove 15 formed by continuing a first recessed part 11 formed on an outer peripheral surface of a shoulder part of the male joint 3 and a second recessed part 13 formed on an outer peripheral surface of a tip part of the female joint 5 in the fitting completion state and a shear key 17 installed in the key groove 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steel pipe joint that includes a screw-type male joint and a female joint and is attached to an end of a steel pipe such as a steel pipe pile and joins the steel pipe. The present invention relates to a threaded joint including a reverse rotation prevention mechanism that prevents reverse rotation of the joint.

A screw joint consisting of a male joint and a female joint has a high rotational resistance, because if it continues to turn in the direction of the screw, the torque will rise significantly and it will be difficult to tighten further. However, when turning in the opposite direction, the screw is easily removed.
Therefore, when using a threaded joint to join a rotating penetration pile that performs forward rotation and reverse rotation, pins and bolts for preventing reverse rotation as shown in FIGS. 11 to 13 of Patent Document 1 are installed. It is common to do.
In addition, the key hole and screw hole for installing a pin and a bolt are opened according to the position where the male joint and the female joint have been fitted.

Japanese Patent No. 3747594

  However, if you try to place pins and bolts so as not to interfere with the thread of the threaded joint, it is necessary to lengthen the threaded joint by that amount, which may increase the length of the threaded joint itself and increase the cost. was there.

In addition, it is common to insert a pin or bolt into the key hole or screw hole formed in the male joint and female joint when the mating is completed, but the positions of the hole and bolt hole match between the male joint and female joint. It is difficult to see from the outside, and it is not known until a pin or bolt is inserted.
Therefore, in practice, it is necessary to set the hole diameter provided in either the male joint or the female joint to be sufficiently larger than the pin diameter or the bolt diameter. Therefore, there is a possibility that useless rotation may occur before the pin or bolt comes into contact with the hole edge during reverse rotation and the resistance force is exerted, and the construction speed is adversely affected.

  The present invention has been made to solve such a problem, and provides a threaded joint provided with a reverse rotation prevention mechanism that prevents the threaded joint from becoming large and prevents unnecessary rotation from occurring during reverse rotation. The purpose is to do.

(1) A threaded joint provided with a reverse rotation prevention mechanism according to the present invention comprises a threaded male joint and a female joint, and is a steel pipe joint that is attached to an end of a steel pipe and joins the steel pipe, A reverse rotation prevention mechanism for preventing reverse rotation of the male joint and the female joint in a fitted state, the reverse rotation prevention mechanism including a first recess formed on an outer peripheral surface of a shoulder portion of the male joint; The second recess formed on the outer peripheral surface of the distal end portion of the female joint includes a key groove formed by continuation in a fitting completed state, and a shear key installed in the key groove. It is characterized by this.

(2) Further, in the above-described (1), one of the first recess and the second recess is set to have a longer length in the rotation direction of the recess than the other. is there.

(3) Further, in the above (1) or (2), it has a disengagement prevention member for preventing the shear key from coming off from the key groove in a state where the shear key is installed. It is a feature.

A threaded joint provided with a reverse rotation prevention mechanism according to the present invention comprises a threaded male joint and a female joint, and is a steel pipe joint that is attached to an end of a steel pipe to join the steel pipe, and the fitting is completed A reverse rotation prevention mechanism for preventing reverse rotation of the male joint and the female joint in the state, the reverse rotation prevention mechanism comprising: a first recess formed on an outer peripheral surface of a shoulder portion of the male joint; The second recess formed on the outer peripheral surface of the joint tip is provided with a key groove formed by continuation in a fitted state, and a shear key installed in the key groove. It is not necessary to lengthen the threaded joint to form the keyway, and the cost is not increased.
In addition, since the keyway can be seen from the outside, the workability of installing the shear key is excellent at each stage, and it is not necessary to enlarge the keyway to enable alignment in an invisible state. The size of the groove may be the minimum necessary.

It is explanatory drawing of the threaded coupling provided with the reverse rotation prevention mechanism of this Embodiment, Comprising: It is a longitudinal cross-sectional view. It is an arrow AA figure of FIG. It is an enlarged view of arrow BB of FIG.

A threaded joint 1 having a reverse rotation prevention mechanism according to an embodiment of the present invention is composed of a threaded male joint 3 and a female joint 5 as shown in FIGS. A steel pipe joint that is attached and joins the steel pipe 7 and has a reverse rotation prevention mechanism 9 that prevents reverse rotation of the male joint 3 and the female joint 5 when the fitting is completed.
Hereinafter, the reverse rotation preventing mechanism 9 which is a characteristic part of the present embodiment will be described in detail.

The reverse rotation prevention mechanism 9 includes a key groove 15 formed by a first recess 11 formed in a shoulder portion of the male joint 3 and a second recess 13 formed in a tip portion of the female joint 5, and a key groove 15. And a detachment prevention screw 19 as a detachment prevention member for preventing the shear key 17 from detaching from the key groove 15.
Hereinafter, each configuration will be described in detail.

<Keyway>
The key groove 15 is formed by the first recessed portion 11 and the second recessed portion 13 being continuous in a fitted state, that is, the opening of the first recessed portion 11 and the second recessed portion 13 is connected. It is preferable to provide a plurality in the circumferential direction. In this example, four places are provided in the circumferential direction as shown in FIG.
Since the key groove 15 is composed of the first concave portion 11 formed in the shoulder portion and the second concave portion 13 formed in the distal end portion of the female joint 5, the joint length is increased in order to form the key groove 15. There is no need to do.

As shown in FIG. 3, the first recess 11 has a semicircular recess shape in which half of the shear key 17 (upper half in the figure) can be inserted and the lower side in the figure opens.
Further, as shown in FIG. 3, the second recess 13 has a shape in which half of the shear key 17 (lower half in the figure) can be inserted, is long in the rotation direction, and has a long circle halved in the major axis direction. ing. The second recess 13 is open on the upper side in the figure, and the opening and the opening of the first recess 11 are continuous when the screw joint 1 is completely fitted.

In addition, it is preferable that the 1st recessed part 11 and the 2nd recessed part 13 are provided so that the rearmost walls of a fitting rotation direction may continue in a fitting completion state, as shown in FIG. By doing so, even if the male joint 3 tries to move (rotate) relative to the female joint 5 during the reverse rotation, the shear key 17 acts immediately and almost no unnecessary rotation occurs. .
Here, the arrow of FIG. 3 has shown the relative rotation direction of the male joint 3 (upper side in the figure) with respect to the female joint 5 (lower side in the figure).

<Shear key>
The shear key 17 has a disk shape having a predetermined thickness, and is installed so as to straddle the first recess 11 and the second recess 13 to prevent reverse rotation of the male joint 3 and the female joint 5.
The shear key 17 is formed with an insertion hole 21 into which a later-described detachment prevention screw 19 is inserted, and a counterbore portion 23 in which a head portion 19 b of the detachment prevention screw 19 is accommodated. In the present embodiment, as will be described later, since the detachment prevention screw 19 is attached to the male joint 3, the insertion hole 21 is formed at a position that is biased upward from the center of the shear key 17 (see FIG. 3).

<Screw prevention screw>
The detachment prevention screw 19 has a bolt shape having a shaft portion 19a and a head portion 19b each having a screw formed at the tip. The shaft portion 19 a is screwed into a screw hole provided in the male joint 3 and attached to the male joint 3, and the head portion 19 b is accommodated in the counterbore portion 23 of the shear key 17. The detachment prevention screw 19 supports the shear key 17 by the shaft portion 19a and the head portion 19b, and prevents the shear key 17 from coming off.

In a state in which the shear key 17 is installed in the key groove 15 and the detachment prevention screw 19 is attached (see FIGS. 1 and 3), the space between the peripheral wall of the first recess 11 and the peripheral surface of the shear key 17 is substantially uniform. There is only a slight gap S ₁ (about 0.5 mm), and both are close to each other.
On the other hand, a slight gap is formed on the right side of the shear key 17 in the drawing between the peripheral wall of the second recess 13 and the peripheral surface of the shear key 17, and the shear key 17 is fitted and rotated on the left side in the drawing. A gap is formed so that it can move slightly in the direction.

Further, a predetermined gap S ₂ (about 1 mm) is formed between the insertion hole 21 of the shear key 17 and the shaft portion 19 a of the disengagement prevention screw 19 and between the head portion 19 b of the shear key 17 and the peripheral wall of the counterbore portion 23. ing.
By making the gap S ₂ larger than the gap S ₁ , no shear force acts on the detachment prevention screw 19. That is, the detachment prevention screw 19 does not restrict the movement of the shear key 17 in the rotational direction, but acts to restrict the shear key 17 from moving in the radial direction.

Next, when the steel pipe pile to which the female joint 5 is attached is rotated and penetrated into the ground, and the steel pipe pile to which the male joint 3 is attached is jointed to the action of the anti-rotation mechanism configured as described above. Will be described as an example.
The steel pipe pile to which the male joint 3 is attached is disposed above the female joint 5, and the male joint 3 is rotated with respect to the female joint 5 to fit them together. By making a predetermined number of rotations so that the alignment marks coincide with each other, the second recess 13 of the female joint 5 and the first recess 11 of the male joint 3 are continuously formed to form a key groove 15. Although the shear key 17 is installed in the key groove 15, since the key groove 15 can be easily seen from the outside, it is compared with the case where it is not known whether the key hole is aligned unless a pin or bolt is inserted as in the conventional example. Then, it is excellent in workability at each stage.

Moreover, since the 2nd recessed part 13 becomes a long shape in the rotation direction, even if the 1st recessed part 11 and the 2nd recessed part 13 have shifted | deviated somewhat in the rotation direction, the shear key 17 can be installed.
Thereafter, in order to prevent the shearing key 17 from coming off, a come-off prevention screw 19 is installed.

When all the shear keys 17 (four in this example) are installed, the spliced steel pipe pile is rotated and penetrates into the ground. As shown in FIG. 3, the direction of rotational penetration is the same as the direction in which the threaded joint 1 is fitted. Therefore, regardless of the presence or absence of the shear key 17, the threaded joint 1 can rotationally penetrate the pile without loosening.
Of course, in the case of a rotating penetrating pile, if the ground resistance is large, a larger torque than the fitting completion state of the screw joint 1 may act and the screw joint 1 may further rotate in the fitting direction. Since the second recess 13 is a long hole, the threaded joint 1 can be rotated without applying a shearing force to the shearing key 17.

When the steel pipe pile is rotated in reverse during the penetration of the steel pipe pile or when the steel pipe pile is pulled out, the shear key 17 is installed across the first concave portion 11 of the male joint 3 and the second concave portion 13 of the female joint 5. Therefore, the male joint 3 and the female joint 5 cannot rotate relatively, and reverse rotation is prevented. Since the gap S ₁ is smaller than the gap S ₂ , when the reverse rotation is performed, the shaft 19 a of the disengagement prevention screw 19 is connected to the shear key 17 when the peripheral wall of the shear key 17 and the peripheral wall of the key groove 15 abut. The shearing force acts on the detachment prevention screw 19 because it comes into contact with the insertion hole 21 of the squeeze hole or the head portion 19b of the detachment prevention screw 19 contacts the peripheral wall of the counterbore portion 23 of the shear key 17. There is nothing.

As described above, in the present embodiment, the first recess 11 is formed in the shoulder portion of the male joint 3, the second recess 13 is formed in the distal end portion of the female joint 5, and the male joint 3 and the female joint 5 are formed. Since the key groove 15 is formed when the fitting is completed, it is not necessary to lengthen the threaded joint 1 in order to form the key groove 15, and the cost is not increased.
In addition, since the key groove 15 can be visually recognized from the outside, the workability of installing the shear key 17 is excellent in each stage, and the key groove 15 can be aligned in a state where it cannot be seen as in the conventional example. It is not necessary to enlarge the (key hole), the size of the key groove 15 may be the minimum necessary, and unnecessary rotation does not occur during construction (during reverse rotation).

  In the above embodiment, the example in which the length in the rotation direction of the second recess 13 formed in the female joint 5 is set longer than the first recess 11 formed in the male joint 3 is shown. Conversely, the length in the rotational direction of the first recess 11 formed in the male joint 3 may be set longer than the second recess 13 formed in the female joint 5. In this case, the detachment prevention screw 19 is attached to the second recess 13 side.

In the above embodiment, an example in which the detachment prevention screw 19 is attached has been described. However, the shape of the first recess 11, the second recess 13, and the shear key 17 is the same as that of the first recess 11 and the second recess 13. If it is made not to come off only by inserting 17, the removal prevention screw 19 is unnecessary.
In the above-described embodiment, the second recess 13 has a semi-long hole shape. However, the second recess 13 may also have a shape along the peripheral wall of the shear key 17 in the same manner as the first recess 11. Even in this case, it is possible to fit the shear key 17 by fitting the threaded joint 1 in a state where the matching marks are matched, and if the rigidity of the shear key 17 is increased, the fitting is possible. Even if a shearing force is applied during rotation in the combined rotation direction, it does not break.

DESCRIPTION OF SYMBOLS 1 Thread joint 3 Male joint 5 Female joint 7 Steel pipe 9 Reverse rotation prevention mechanism 11 1st recessed part 13 2nd recessed part 15 Key groove 17 Shear key 19 Detachment prevention screw 19a Shaft part 19b Head part 21 Insertion hole 23 Counterbore part

Claims (3)

It consists of a screw-type male joint and female joint, and is a steel pipe joint that is attached to the end of a steel pipe and joins the steel pipe,
Having a reverse rotation prevention mechanism for preventing reverse rotation of the male joint and the female joint in a fitted state;
The reverse rotation prevention mechanism is
A key formed by a first recessed portion formed on the outer peripheral surface of the shoulder portion of the male joint and a second recessed portion formed on the outer peripheral surface of the distal end portion of the female joint continuing in a fitted state. A threaded joint provided with a reverse rotation prevention mechanism, characterized by comprising a groove and a shear key installed in the key groove.   The threaded joint provided with the reverse rotation prevention mechanism according to claim 1, wherein one of the first recess and the second recess is set to have a longer length in the rotation direction of the recess than the other.   The screw having a reverse rotation prevention mechanism according to claim 1 or 2, further comprising a disengagement prevention member for preventing the shear key from being detached from the keyway when the shear key is installed. Fittings.

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