JP2002220828A - Structure of screw-type joint for piles equipped with anti-rotation mechanism - Google Patents

Abstract

(57) [Summary] [Problem] To be able to connect upper and lower piles so that the driven lower pile rotates following the reverse rotation of the upper pile, and to perform the connection easily and with good accuracy and quality. Provided is a structure of a threaded joint for piles provided with a mechanism for preventing rotation from rotating. SOLUTION: A joint structure for connecting upper and lower piles 1 and 2 by screwing a female screw joint member 3 provided at an upper end of a lower pile 1 and a male screw joint member 4 provided at a lower end of an upper pile 2. And has a reverse rotation locking mechanism. The reverse rotation locking mechanism is formed by driving the linear key 5 from the outside of the female screw joint member 3 into the key hole 8 through the key introduction hole 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a threaded joint for piles provided with a mechanism for preventing reverse rotation.

[0002]

2. Description of the Related Art For example, when a steel pipe pile is driven by rotary press-fitting, the end of the next steel pipe pile may be connected in series to the upper end of the driven steel pipe pile and further driven. In some cases, after the lower pile and the upper pile are connected to each other, the upper pile is rotated in the opposite direction, so that the lower pile also needs to be rotated in accordance with the rotation.

For such a case, conventionally, the connection between the upper pile and the lower pile is performed by driving a lower pile 71 and then using a joint pipe 72 as a backing hardware as shown in FIG. Arranged in the steel pipe so as to pass to the upper and lower steel pipe piles 71, 73,
At the site, the upper and lower steel pipe piles 71 and 73 were joined and integrated by welding W.

[0004]

However, the welding W
In the method of connecting the upper and lower steel pipe piles 71 and 73 by
Since the connection work is outdoors, welding cannot be performed in rainy weather or strong wind, welding equipment and a welder are required, the quality of the joint W is easily affected by the skill of the welding worker, and time is required for joining. However, there is a problem that it is difficult to properly manage the vertical accuracy of the connected upper pile 73.

In view of the above-mentioned conventional problems, the present invention can connect upper and lower piles so that the driven lower pile rotates following the upper pile when the upper pile is rotated in the reverse direction. An object of the present invention is to make it possible to easily perform the connection with good accuracy and quality.

[0006]

SUMMARY OF THE INVENTION The above object is achieved by screwing a female screw joint provided at one end of a pile and a male screw joint provided at an end of the other pile. A threaded joint for a pile provided with a reverse rotation locking mechanism that does not cause the screw to loosen even when rotated in reverse, and a groove extending in the circumferential direction is provided on the outer periphery of the male screw joint, A groove extending in the circumferential direction is also provided on the inner periphery of the female screw joint, and a key hole extending in the circumferential direction is formed by these grooves by screwing the two joints, and A key introduction hole is formed in the female screw joint portion, which extends tangentially from the key hole and opens to the outer peripheral portion of the female screw joint portion, and a linear key is provided, and the linear key is provided outside the female screw joint portion. Key introduction from Wherein the implanting the key hole, is solved by the structure of the pile for threaded joints having a reverse slow stop mechanism, characterized in that it has been made as forming a reverse slow stop mechanism through.

In this structure, the upper and lower stakes are connected in a state where the upper and lower piles are prevented from rotating in reverse only by screwing the male and female screws into each other and then driving the linear key. Therefore, it is easy to connect the upper and lower piles,
In addition, both accuracy and quality can be achieved satisfactorily.

Further, the linear keys can be interposed over a wide area in the circumferential direction only by hitting a small number of linear keys, such as one or two, so that a stable reverse rotation preventing state is formed. be able to.

Another object of the present invention is to connect piles by screwing a female screw joint provided at an end of one pile and a male screw joint provided at an end of the other pile. And a screw type joint for piles provided with a reverse rotation locking mechanism that does not cause loosening of the screw even when rotated in the reverse direction,
Grooves extending in the circumferential direction are provided on the outer periphery of the male screw joint portion, and grooves extending in the circumferential direction are also provided on the inner periphery of the female screw joint portion. The two joint portions are screwed to form a circle formed by these grooves. A key hole extending in the circumferential direction is formed, and a C-ring spring key is provided. The C-ring spring key can be fitted and set in a groove of one joint portion, In this set state, the joint part can be opened and closed elastically deformable in the bottom direction of the groove, and the other joint part is screwed with the C-ring spring key set in the one joint part. An inclined portion is provided for elastically opening and closing toward the bottom of the groove of the one joint portion, and the C-ring spring key is restored after being elastically opened and closed by the inclined portion in the process of screwing the joint portions. In Passed in both the groove of the hole, it is solved by the structure of the pile for threaded joints having a reverse slow stop mechanism, characterized in that have been made as forming a reverse slow stop mechanism.

[0010] In this structure, the upper and lower piles are connected in the reverse rotation preventing state only by setting the C-ring spring key in the groove of one joint portion and screwing the male and female screws together.
Therefore, the connection of the upper and lower piles can be easily performed, and both the accuracy and the quality can be favorably performed.

In particular, the C-ring spring key can be set in advance in the groove of one of the joints, so that the upper and lower piles are connected only by screwing the male and female screws together to reverse rotation. It will be in a stopped state, and the connection of the upper and lower piles can be more easily performed.

In addition, the C-ring spring key can be interposed between the two joints over a wide range in the circumferential direction, so that a stable reverse rotation preventing state can be formed.

[0013] Another object of the present invention is to connect piles by screwing a female screw joint provided at an end of one pile and a male screw joint provided at an end of the other pile. And a screw type joint for piles provided with a reverse rotation locking mechanism that does not cause loosening of the screw even when rotated in the reverse direction,
A concave portion is provided on the outer peripheral surface of the female screw joint portion, and in a male-female screwed state, the bottom side of the concave portion is caulked from the outer peripheral side of the female screw joint portion to the outer peripheral surface of the male screw joint portion, so that a reverse rotation preventing mechanism is provided. The present invention is also solved by a structure of a threaded joint for piles provided with a reverse rotation preventing mechanism, characterized in that it is formed.

In this joint structure, after the male and female screws are screwed together, the tool is used to crimp the bottom of the recess from the outer peripheral side of the female screw joint to the outer peripheral surface of the male screw joint. The upper and lower piles are connected in a state of preventing rotation. Therefore, the connection of the upper and lower piles can be easily performed, and both the accuracy and the quality can be favorably performed.

In addition, there is no need for a component for preventing reverse rotation, and the reverse rotation can be prevented simply by swaging with a tool. In particular, by forming the caulked portions at a plurality of locations in the circumferential direction, it is possible to form a firm reverse-locking state, and yet there is a great advantage that a component for the reverse-locking is not required.

In addition, a recess is formed in the portion to be caulked, so that the position of the recess can be easily grasped by an operator, and the tool can be positioned in the recess, thereby facilitating construction. Can be.

Further, since the caulking portion is a concave portion so that the meat on the bottom side can be easily deformed, the meat at that portion can be easily deformed with a tool. A large wall thickness can be secured, and the upper and lower piles can be firmly connected by screwing the joints together.

In the case of crimping against the screw surface of the male screw joint, a firm reverse rotation preventing state can be formed by using the uneven screw surface of the male screw joint.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings. In the embodiment, a steel pipe pile driven by rotary press-fitting is used.

In the steel pipe pile according to the first embodiment shown in FIGS. 1 to 4, reference numeral 1 denotes a lower pile made of a steel pipe, 2 denotes an upper pile made of a steel pipe, and a lower end of the upper pile 2 has a male screw joint made of steel. The member 4 is attached by welding, and a female screw joint member made of steel is attached to the upper end of the lower pile 1 by welding, and these joint members 3 and 4 constitute a male / female screw joint portion. The joint members 3 and 4 are joined to the ends of the piles in advance at a factory or the like. Reference numeral 5 denotes a linear key (see FIGS. 3 and 4).

As shown in FIG. 1, the male screw coupling member 4 is provided with a flange 4c that projects outward from the base end of the cylindrical body 4b of the outer peripheral screw 4a. A flange 3c is provided on the base end side of the cylindrical body 3b of the inner peripheral screw 3a to protrude inward. The male and female joint members 3, 4 are screwed together to form the female screw joint member 3. Of the male screw joint member 4 abuts on the outer flange portion 4c of the male screw joint member 4 or / and the end of the male screw joint member 4 abuts on the inner flange portion 3c of the female screw joint member 3.
It is designed to obtain a screwed state.

Further, the cylindrical main body 4 of the male screw joint member 4
An annular groove 7 having a rectangular cross section extending in the circumferential direction is provided on the outer peripheral portion of the intermediate portion in the axial direction of b, and the inner peripheral portion of the axially intermediate portion of the cylindrical main body 3b of the female screw coupling member 3. Similarly, an annular groove 6 having a rectangular cross section extending in the circumferential direction is also provided, and as shown in FIGS. 2A and 2B, the male and female joint members 3 and 4 are brought into the above-mentioned threaded state. Thus, an annular key hole 8 extending in the circumferential direction of a rectangular cross section is formed by the annular grooves 6 and 7.

Then, the female screw coupling member 3 is
As shown in (b), in the key hole 8, straight key introduction holes 9, 9 extending in one tangential direction are formed at two positions which are different from each other by 180 ° in the circumferential direction, and these key introduction holes 9 are formed. , 9 have openings 9 a, 9 a in the outer peripheral portion of the female screw joint member 3.

As shown in FIG. 3 and FIG.
Is made of steel, has two straight lines, and has a rectangular cross section. The size of the cross section is such that the linear key 5 It is designed to be of a size that allows it to protrude into the other groove even when it is in contact with the bottom of the.

The upper and lower stakes 1 and 2 can be connected in the reverse rotation preventing state as follows. That is, after the lower pile 1 is driven in by rotary press-fitting, the upper pile 2 is lifted and rotated, and the male and female screw joint members 3 and 4 are screwed together as shown in FIGS. After the joint members 3 and 4 are screwed together, as shown in FIGS.
The linear keys 5 and 5 are driven from a and 9a. By this driving, the linear keys 5 and 5 enter the key hole 8 through the key introduction holes 9 and 9 and enter the key hole 8 while being deformed in the circumferential direction and curved.

The driving depth of the linear key 5 is set to be short of the intersection between the other key introduction hole and the key hole. Thus, the substantially entire range of the key hole 8 is filled with the linear keys 5 and 5.

It is to be noted that if the linear key 5 is advanced into the intersection of the other key introduction hole and the key hole, it becomes difficult to drive the other linear key 5, so that it is prevented. For the purpose, the length dimension may be limited so that when the entire length is driven, the tip is located before the intersection, or the driving depth may be limited by marking the linear key 5 or the like. Good.

Thus, FIGS. 3 (b) and 4 (a)
As shown in (b), when the linear keys 5 and 5 are driven, a reverse rotation preventing mechanism is formed. Even when the upper pile 2 is rotated in the reverse direction, the linear keys 5 and 5 in the key hole 8 are not rotated. The joint members 3, 4 function to prevent loosening of the screws.

In the above-described joint structure, the linear key 5 in the key hole 8 prevents the screws of the male and female screw joint members 3 and 4 from being loosened.
Are connected so that when the driven lower pile 1 rotates the upper pile 2 in the reverse direction, the lower pile 1 rotates following the reverse rotation.

Moreover, both male and female screw joint members 3,
After the screw 4 is screwed, the linear keys 5 and 5 need only be driven in from the side. Therefore, the work of connecting the upper and lower piles provided with the reverse rotation preventing mechanism is easy, and both the accuracy and the quality are good. Can be carried out.

In addition, as shown in FIG. 3 (c), the linear keys 5 and 5 can be interposed over a wide area in the circumferential direction of the joint portion, and a firm reverse locking state can be formed. In addition, since the number of the linear keys 5 is two, a small number of hits are sufficient, and the hitting can be performed smoothly without increasing the hitting resistance.

Further, the grooves 6 and 7 are provided with respective screw joint members 3 and
Since it is provided at the center part or the middle part between the ends in the axial direction of 4, the strong reverse rotation preventing state can be formed.

In the above embodiment, the linear key is set to 2
Although the actual driving is shown, depending on the diameter of the pile, for example, when the diameter of the pile is small, it may be driven so as to cover substantially the entire circumference with one linear key, or the diameter of the pile may be reduced. If it is large, three or four or more linear keys may be driven by increasing the number of key introduction holes.

In the steel pipe pile according to the second embodiment shown in FIGS. 5 to 9, the upper and lower piles 1 and 2 are screw-connected to each other by using a C-ring spring key 11 so as to prevent reverse rotation.

That is, as shown in FIG. 5, an annular groove 6 having a rectangular cross section extending in the circumferential direction is provided adjacent to the inner peripheral thread 3a of the female thread coupling member 3 at the depth side thereof. An annular groove 7 having a rectangular cross section extending in the circumferential direction is provided adjacent to the distal end side of the outer peripheral screw 4a, and as shown in FIG. An annular key hole 8 extending in the circumferential direction by the grooves 6 and 7 is formed.

As shown in FIGS. 5 and 6, the C-ring spring key 11 is set in the annular groove 6 of the female screw coupling member 3 before the coupling members 3 and 4 are screwed together. The C-ring spring key 11 can be set in the annular groove 6 of the female screw coupling member 3 by deforming to reduce the diameter and then elastically restoring.
In this set state, the C-ring spring key 11 projects in such a manner that a half on the radially outward side is inserted into the annular groove 6 of the female screw coupling member 3 at a distance from the bottom surface thereof,
The radially inward half portion projects out of the annular groove 6 of the female screw coupling member 3 so that it can project into the annular groove 7 of the male screw coupling member 4.

The tip of the male screw coupling member 4 is
A tapered conical inclined portion 12 is formed.
The diameter of the tip of 2 is formed smaller than the inner diameter of the C-ring spring key 11 in the restored state, and the C-ring spring key 11 is expanded and deformed when the inclined portion 12 enters the C-ring spring key 11. The male screw joint member 4 can be fitted into the annular groove 7.

The upper and lower stakes 1 and 2 can be connected in a reverse rotation preventing state as follows. That is, after the lower pile 1 is driven by rotary press-fitting, the upper pile 2 is lifted and rotated, and the male and female screw coupling members 3 and 4 are screwed together as shown in FIGS. 7 and 8. C-ring spring key 1
Reference numeral 1 denotes a female threaded joint member 3 at the upper end of the lower pile 1 in a factory or before the upper and lower piles 1 and 2 are screwed together.
May be set in the annular groove 6.

In this screwing process, as shown in FIGS. 8A and 8B, the inclined portion 12 of the male screw joint member 4 projects into the C-ring spring key 11 set on the female screw joint member 3. The C-ring spring key 11 is opened, and as shown in FIGS. 8 (C) and 9 (A) (B), the C-ring spring key 11 is fitted into the annular groove 7 of the male screw coupling member 4 by elastic restoration. The screw joint members 3 and 4 are screwed. In this way, a reverse rotation preventing mechanism is formed by the C ring spring key 11, and even when the upper pile 2 is rotated in the reverse direction, the C ring spring key 11 in the key hole 8 prevents the screws of the joint members 3, 4 from loosening. To work.

In the above-mentioned joint structure, the C-ring spring key 11 in the key hole 8 acts to prevent the screws of the male and female screw joint members 3 and 4 from loosening. 1, 2 are connected so that when the driven lower pile 1 reversely rotates the upper pile 2, the lower pile 1 rotates following the reverse rotation.

Moreover, the upper and lower piles 1 and 2 can be connected in the reverse rotation preventing state only by turning the male and female screw joint members 3 and 4 into a threaded state. The connection work of the upper and lower piles 1 and 2 can be performed very easily, and both accuracy and quality can be excellently performed.

In addition, the C-ring spring key 11 can be interposed over a wide area in the circumferential direction of the joint portion.
A firm anti-rotation state can be formed.

In the above embodiment, the case where the C-ring spring key 11 is set on the female screw coupling member 3 and the male screw coupling member 4 is provided with an inclined portion 12 for expanding the diameter of the C-ring spring key 11 is shown. But on the contrary, C
The ring spring key may be set on the male screw coupling member, and the female screw coupling member may be provided with an inclined portion for reducing the diameter of the C ring spring key.

In the steel pipe pile according to the third embodiment shown in FIGS. 10 to 12, the female screw joint member 3 has three concave portions in the circumferential direction on the outer peripheral surface corresponding to the axially intermediate position of the screw 3a on the inner peripheral side. Places 13 are formed at intervals, and the thickness in the bottom direction in the recesses 13 is thin. Recess 1
As shown in FIG. 10 (b), 3 may be provided on the back side of the ridge of the inner peripheral thread of the female screw joint member 3, or may be provided on the back side of the valley or the valley valley. It may be provided on the back side of the boundary between the parts.

The upper and lower stakes 1 and 2 can be connected in a reverse rotation preventing state as follows. That is, after the lower pile 1 is driven by rotary press-fitting, the upper pile 2 is lifted and rotated, and the male and female screw coupling members 3 and 4 are screwed together as shown in FIGS. Then, the joint members 3 and 4 are screwed to each other. After a while, FIG.
As shown in (b) and FIG. 12, a tool 14 is used to caulk the bottom surface of the recesses 13... From the outer peripheral side of the female screw joint member 3 to the screw surface 4 a of the male screw joint member 4. As a result, the upper and lower piles 1 and 2 are connected in the reverse rotation preventing state.

As described above, in this joint structure, after the male and female screws 3a and 4a are screwed together, the tool 13 is used to remove the meat from the outer peripheral side of the female screw joint member 3 to the bottom of the recess 13. Only by caulking the screw surface 4a of the member 4, the upper and lower piles 1 and 2 can be connected in a reverse rotation preventing state, so that the connection of the upper and lower piles 1 and 2 can be easily performed with accuracy and quality. Can be performed well.

Further, since no component for preventing reverse rotation is required, and the mechanism for preventing reverse rotation can be formed only by caulking using the tool 14, the number of components is small and the management thereof is easy. In particular, by forming the caulked portions at a plurality of locations in the circumferential direction, it is possible to form a firm reverse-locking state, and yet there is a great advantage that a component for the reverse-locking is not required.

In addition, a recess 13 is formed in the portion to be swaged, so that the position of the recess 13 can be easily grasped by an operator, and the tool can be positioned in the recess 13 so that reverse rotation The construction of the stopper can be easily performed.

Further, since the caulking portion is formed as a recess 13 so that the meat on the bottom side can be easily deformed, the meat at that portion can be easily deformed with the tool 14, and the female screw A large wall thickness of the joint member 3 can be ensured, and the upper and lower piles 1 and 2 can be firmly connected by screwing the joint members 3 and 4 together. Further, the thickness of the female screw joint member 3 is changed to the male screw joint member 4.
Is crimped against the screw surface 4a, so that a firm reverse rotation preventing state can be formed.

As the tool 14, it is preferable to use a tool that can caulk three circumferential locations including the recesses 13 at a time. As such a tool, various tools such as a torque wrench type, a hydraulic cylinder type, and a ratchet wrench type may be used. Further, the number of recesses may be one in the circumferential direction, or two or four or more in the circumferential direction.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention. For example, in the above-described embodiment, a case is shown in which the joint member is joined to the end of the pile to be provided with a joint, but a joint that is integral with the end of the pile may be formed at the end of the pile. Good. Further, a male screw joint may be provided at the upper end of the lower pile, and a female screw joint may be provided at the lower end of the lower pile.
In addition, it goes without saying that the present invention can be used not only for steel pipe piles but also for various piles.

[0052]

According to the present invention as described above, the upper and lower piles can be connected so that the driven lower pile rotates following the reverse rotation of the upper pile, and the connection is facilitated. In addition, both accuracy and quality can be achieved satisfactorily.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view showing a joint structure according to a first embodiment in a separated state before screwing.

FIG. 2A is a cross-sectional side view of a screwed state, and FIG. 2B is a cross-sectional view taken along line II of FIG.

3A and 3B sequentially show a method of driving a linear key. FIG. 3A is a cross-sectional plan view before driving, FIG. 3B is a cross-sectional plan view during driving, and FIG. It is a sectional plan view.

FIG. 4A is a cross-sectional side view of a state where a linear key is driven, and FIG. 4B is an enlarged cross-sectional side view of a linear key driven portion.

FIG. 5 is a cross-sectional side view showing a joint structure according to a second embodiment, before screwing and with a C-ring spring key also in a separated state.

FIG. 6A is a cross-sectional side view showing a state in which a C-ring spring key is set on a female screw joint member, and FIG. 6B is a cross-sectional view taken along the line II-II of FIG.

FIG. 7 is a sectional side view showing a state after the start of screwing.

FIGS. 8A and 8B sequentially show a process from a threaded state to a threaded state. FIG. 8A is a cross-sectional side view before the C-ring spring key is expanded, and FIG. FIG. 3 (C) is a cross-sectional side view of the return state.

FIG. 9A is a cross-sectional side view showing a state in which a C-ring spring key is set in a key hole, and FIG.
FIG. 3 is a sectional view taken along line II-III.

FIG. 10 is a cross-sectional side view showing a joint structure according to a third embodiment before screwing.

FIG. 11A is a sectional side view of a screwed state, and FIG.
FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 12A is a cross-sectional side view before crimping, and FIG. 12C is a cross-sectional side view after crimping.

FIG. 13 is a cross-sectional side view showing a conventional joint structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lower pile 2 ... Upper pile 3 ... Female screw joint member (Female screw joint part) 4 ... Male screw joint member (Male screw joint part) 5 ... Linear key 6 ... Annular groove (groove extending in the circumferential direction) 7 ... Annular groove ( 8 ... key hole 9 ... key introduction hole 11 ... C-ring spring key 12 ... inclined portion 13 ... recess

Continuation of the front page (72) Inventor Sadao Shimizu 3-5-5 Umeda, Kita-ku, Osaka City, Osaka Prefecture Inside Daiwa House Industry Co., Ltd. (72) Inventor Hiroshi Kinoshita 3-3-5, Umeda, Kita-ku, Osaka City, Osaka Prefecture No. Daiwa House Industry Co., Ltd. (72) Inventor Shigeru Hirata 3-3-5 Umeda, Kita-ku, Osaka-shi, Osaka Prefecture Daiwa House Industry Co., Ltd. 1-31-1, Astec Irie, Inc. (72) Inventor Hideki Asamoto 1-3-1, Otani, Yawata-Higashi-ku, Kitakyushu-shi, Fukuoka Prefecture Astec Irie, Inc. (72) Inventor Jun Itagaki Tamako, Higashimurayama-shi, Tokyo 2-11-11-45, F-term in Fuji Shoji Co., Ltd. (Reference) 2D041 AA02 DB02 DB11

Claims (3)

[Claims] A stake is connected by screwing a female screw joint provided at an end of one pile and a male screw joint provided at an end of the other pile, and rotated in reverse. A threaded joint for piles provided with a reverse rotation preventing mechanism that does not cause loosening of the screw even when a groove extending in the circumferential direction is provided on the outer periphery of the male screw joint, and a circle is similarly formed on the inner periphery of the female screw joint. A groove extending in the circumferential direction is provided, and a key hole extending in the circumferential direction is formed by these grooves by screwing the two joint portions, and the key hole is formed in the female screw joint portion. A key introduction hole extending in a tangential direction from the female screw joint portion and opening to the outer peripheral portion of the female screw joint portion is formed, and a linear key is provided. Hammer Mukoto, the structure of the pile for threaded joints having a reverse slow stop mechanism, characterized in that have been made as forming a reverse slow stop mechanism. 2. The piles are connected to each other by screwing a female screw joint provided at an end of one of the piles and a male screw joint provided at an end of the other pile, and are rotated in reverse. A threaded joint for piles provided with a reverse rotation preventing mechanism that does not cause loosening of the screw even when a groove extending in the circumferential direction is provided on the outer periphery of the male screw joint, and a circle is similarly formed on the inner periphery of the female screw joint. A groove extending in the circumferential direction is provided, and a key hole extending in the circumferential direction is formed by these grooves by screwing the two joint portions, and a C-ring spring key is provided, This C-ring spring key can be set by fitting into the groove of one joint part, and in this set state, it can be opened and closed elastically deformed in the bottom direction of the groove of the joint part. One joint Is provided with an inclined portion for elastically opening and closing the C-ring spring key set in the one joint portion toward the bottom of the groove of the one joint portion during the screwing process. The joint is elastically deformed by the inclined portion during the screwing process between the joints, and is restored and then passed through both the grooves of the key hole to form a reverse rotation preventing mechanism. Structure of threaded joint for pile with mechanism. 3. The piles are connected by screwing a female screw joint provided at an end of one of the piles and a male screw joint provided at an end of the other pile, and are rotated in reverse. A threaded joint for a pile provided with a reverse rotation preventing mechanism that does not cause loosening of the screw even when a recess is provided on the outer peripheral surface of the female screw joint portion, in a male and female threaded state from the outer peripheral side of the female screw joint portion. The thread at the bottom side of the recess is caulked to the outer peripheral surface of the male screw joint to form a reverse rotation preventing mechanism. Construction.