Plug member and mounting and dismounting device therefor

Abstract

A plug member can be mounted to the end of a pipe and removed therefrom by automated operation.

Description

TECHNICAL FIELD

This invention relates to a plug member and a mounting and dismounting device therefor. Specifically, the present invention relates to a plug member which is mounted inside an end portion of a long pipe such as an oil country tubular good when carrying out thread cutting on the pipe in order to prevent shavings and the like formed during the thread cutting from entering the pipe, and a device for mounting the plug member in a pipe or dismounting or removing it from a pipe.

BACKGROUND ART

FIG. 5 is an explanatory view showing thread cutting being carried out on an end of a long pipe such as an oil country tubular good. As shown in FIG. 5, during thread cutting, the vicinity of an end of a pipe P which is undergoing thread cutting is rotatably supported by a chuck 1. Thread cutting is carried out by contacting the portion of the end of the pipe P to undergo thread cutting with a cutting tool 2 which can be adjusted in position relative to the pipe P as the pipe P is being rotated.

During this thread cutting operation, if shavings caused by the cutting or cutting oil enter into the rear of the interior of a long pipe such as an oil country tubular good, the shavings are not only difficult to remove but extra effort is required for their removal. Therefore, Patent Document 1, for example, discloses an invention which prevents shavings or the like from entering into the interior of a pipe by mounting a plug member in the interior of an end of the pipe prior to thread cutting. The plug member disclosed by Patent Document 1 has a seal member which fits in a groove provided in its outer peripheral surface.

However, mounting of the plug member in an end of a pipe and removal of the plug member from the end of the pipe must be carried out manually. Therefore, the plug member interferes with automation of the entire process of performing thread cutting of a pipe, and the time required for thread cutting increases.

Patent Document 2 discloses an invention in which a plug member having a groove provided in the outer peripheral surface of the body thereof is mounted in a pipe with a seal member fitted into the groove, a projecting grip for mounting and dismounting being attached to one end surface of the body of the plug member. According to that invention, the grip can be grasped by a mounting and dismounting device, so mounting of the plug member in the end of a pipe and removal of the plug member from the end of a pipe can be mechanized by a plug member mounting and dismounting device.

Patent Document 1: JP H07-246504 A

Patent Document 2: JP H07-171701 A

DISCLOSURE OF INVENTION

Problem Which the Invention is to Solve

In the invention disclosed in Patent Document 2, a grip projects in a plug member mounted inside a pipe towards the portion of the pipe which is undergoing thread cutting, so shavings produced by thread cutting can easily be wrapped around the grip. If the plug member is removed from the end of a pipe with a mounting and dismounting device in a state in which shavings are wrapped around the grip, due to the presence of the shavings, it becomes difficult for the mounting and dismounting device to grasp the grip with certainty, and the plug member cannot be removed using the plug member mounting and dismounting device.

Furthermore, a mounting and dismounting device for a plug member according to that invention is installed in a pocket of a turret of a tool rest. Therefore, when mounting and dismounting of a plug member is performed on an end of a pipe, it is necessary to carry out two movements in the form of translation and rotation of the turret. As a result, the time required for mounting of the plug member increases and a drive mechanism for the device becomes complicated.

In addition, a pocket in which a mounting and dismounting device for a plug member according to that invention is installed can no longer be used for other purposes. Furthermore, the mounting and dismounting device for a plug member interferes with nearby pockets, and the nearby pockets can also no longer be used.

The problem which the present invention is to solve is that a plug member mounted in the end of a pipe for preventing shavings or the like from entering into the pipe cannot be removed with a mounting and dismounting device for a plug member.

Another problem which the present invention is to solve is that if mounting and dismounting of a plug member is carried out with a mounting and dismounting device, a prolonged time is required for mounting of the plug member, and the mounting and dismounting device interferes not only with the pocket in which the mounting and dismounting device for a plug member is installed but also with other nearby pockets, so the nearby pockets can no longer be used.

Means for Solving the Problem

The present invention is a plug member to be mounted in an end of a pipe which is to undergo thread cutting,

characterized by comprising an outer tube having a proximal end and a distal end (leading end), a shuttle which is installed so as to be able to reciprocate inside the outer tube between the proximal end and the distal end, a cap which is mounted on the distal end of the outer tube to close off the opening of the distal end, and a shuttle biasing spring having one end secured to the cap and the other end secured to the shuttle,

the outer tube having a seal member which is provided on its outer peripheral surface and which forms a seal against a pipe, and a circumferential groove which is formed in its inner peripheral surface in the proximal end portion,

the shuttle being disposed in a predetermined position inside the proximal end portion of the outer tube and preferably having a fitting portion for positioning which is formed on the end face of the shuttle on the side of its proximal end, and

the shuttle biasing spring producing a spring pressing force on the shuttle towards the proximal end when the shuttle moves from the predetermined position towards the distal end.

From another aspect, the present invention is a plug member mounting and dismounting device for mounting the above-described plug member according to the present invention in a pipe or removing it from a pipe, characterized by comprising a tubular holding body which is disposed inside the outer tube so as to be able to move with respect to the outer tube in the axial direction of the outer tube, a rod which has a distal end portion with a conical shape which decreases in outer diameter from its proximal end towards its distal end and which is disposed inside the tubular holding body so as to be able to move with respect to the tubular holding body in the axial direction of the tubular holding body, moving means for independently moving the tubular holding body and the rod, and preferably a stopper which is installed forward of the plug member having its outer tube connected to the tubular holding body and which by abutting thereon the end surface of a pipe on which the plug member is mounted, can simultaneously perform alignment of the plug member and the pipe and mounting of the plug member with respect to the pipe,

wherein the tubular holding body has ball-receiving holes in a predetermined position into which balls which can engage with the circumferential groove of the outer tube can fit so as not to protrude outwards from the outer peripheral surface of the tubular holding body, and when it is inserted into the outer tube through the proximal end of the tube, its distal end can contact the end surface of the proximal end of the shuttle, the tubular body preferably having a fitting portion which is formed on its distal end portion so as to fit the fitting portion of the shuttle which is formed on its proximal end, and

the rod can make the balls protrude outwards from the outer peripheral surface of the tubular holding body and engage with the circumferential groove to connect the tubular holding body and the outer tube by moving relative to the tubular holding body so as to contact its distal end portion with the balls, and it can release the connection between the tubular holding body and the outer tube by moving relative to the tubular holding body so as to retracting its distal end portion from the balls and let the balls fit into the ball-receiving holes.

EFFECTS OF THE INVENTION

According to the present invention, because a plug member is mounted and dismounted by holding the interior of the plug member, shavings produced by thread cutting can be completely prevented from becoming wrapped around the plug member. Therefore, not only mounting of the plug member in the end of a pipe but also removal from the end of a pipe can be mechanized and automated by a plug member mounting and dismounting device.

In addition, according to the present invention, alignment of a pipe and mounting of a plug member in a pipe can be simultaneously performed. Therefore, the cycle time required for mounting and dismounting of a plug member can be shortened when considering the overall cycle time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-sectional view of a plug member according to the present invention.

FIG. 2 is a longitudinal cross-sectional view showing the main portion of a mounting and dismounting device for a plug member according to the present invention when a plug member according to the present invention is connected thereto and inserted into a long pipe.

FIG. 3 is an overall view of a mounting and dismounting device for a plug member according to the present invention as viewed from the side.

FIG. 4 is a sectional view taken along line A-A of FIG. 3.

FIG. 5 is a schematic view of a conventional end portion working device.

LIST OF REFERENCE NUMERALS

• • 11: plug member; 12: outer tube; 12a: circumferential groove; 13: shuttle; 13a: recess; 14: cap; 15: shuttle biasing spring; 16a, 16b: seal members; 21: plug member mounting and dismounting device; 22: holding member; 22a: ball-receiving hole; 23: rod; 23a: end portion; 24, 25: moving means; 26: balls; 27: stopper

BEST MODE FOR CARRYING OUT THE INVENTION

Below, the best mode for carrying out the present invention will be explained while referring to FIGS. 1-4. In the following explanation, an example will be given of the case in which a pipe is an oil country tubular good.

FIG. 1 is a longitudinal cross-sectional view of a plug member according to the present invention. FIG. 2 is a longitudinal cross-sectional view showing the main portion of a mounting and dismounting device for a plug member according to the present invention when it is connected to a plug member according to the present invention and inserted into a long pipe. FIG. 3 is an overall view of a mounting and dismounting device for a plug member according to the invention as viewed from the side. FIG. 4 is a sectional view taken along line A-A of FIG. 3.

In FIG. 1, 11 indicates a plug member according to the present invention which is mounted inside the end of an oil country tubular good P, for example, which is to undergo thread cutting. The plug member 11 comprises an outer tube 12, a shuttle 13, a cap 14, and a shuttle biasing spring 15.

The outer tube 12 has a proximal end (the end on the right side in FIG. 1) and a distal or leading end (the end on the left side in FIG. 1). The outer tube 12 has sealing members 16a and 16b which are made of hard rubber, for example, and which have a diameter slightly larger than the inner surface of an oil country tubular good P in which the plug member is mounted on the outer peripheral surface of the tube in positions near both ends thereof. The sealing members 16a and 16b are sealed against the oil country tubular good P. A circumferential groove 12a is provided on the inner peripheral surface of the outer tube 12 near the proximal end (the side on which sealing member 16a is mounted). Below-described balls 26 engage with the circumferential groove 12a.

In the embodiment shown in FIG. 1, sealing member 16a is positioned on the outer peripheral surface of the outer tube 12 by an outwardly extending flange of a tubular body 12b, and sealing member 16b is positioned on the outer peripheral surface of the outer tube 12 by a spacer sleeve 12c disposed between it and sealing member 16a.

The shuttle 13 is normally disposed inside the outer tube 12 near the proximal end. The shuttle 13 can move inside the outer tube between the proximal end and the distal end (the opposite end from the proximal end). In the embodiment shown in FIG. 1, the end surface of the shuttle 13 on the side of the proximal end has a recess 13a which serves as a fitting portion for positioning and which is formed in a conical shape having a flat top face and an inner diameter which decreases from the proximal end towards the distal end.

The cap 14 is secured by a screw to the distal end of the outer tube 12 to close off the opening formed at the distal end of the outer tube 12. By securing the cap 14 with a nut 17, the sealing members 16a and 16b in this embodiment can be secured and positioned in the above-described positions.

The shuttle biasing spring 15 is disposed inside the outer tube 12 with one of its ends secured to the cap 14 and its other end secured to the shuttle 13. The shuttle biasing spring 15 biases the shuttle 13 so that when the below-described plug member mounting and dismounting device is not connected to the plug member, the shuttle 13 is positioned inside the outer tube 12 in the proximal end portion (at the position shown in FIG. 1). In the embodiment shown in FIG. 1, a bolt 18 which passes through a through hole provided in the center of the cap 14 is screwed into the shuttle 13, and the shuttle 13 is positioned in the proximal end of the outer tube 12 by adjusting the amount of threaded engagement of the bolt.

A plug member 11 of this embodiment is constituted as described above. Next, a plug member mounting and dismounting device 21 of this embodiment will be explained.

A plug member 11 of this embodiment is automatically mounted and dismounted in the end of an oil country tubular good P by the plug member mounting and dismounting device 21 according to the present invention shown in FIG. 2 and FIG. 3. The plug member mounting and dismounting device 21 comprises a tubular holding body 22, a rod 23, and moving means 24 and 25 for independently moving the tubular holding body 22 and the rod 23.

The tubular holding body 22 has an outer diameter which is slightly smaller than the inner diameter of the outer tube 12 of the plug member 11. It is inserted into the interior of the outer tube 12 of the plug member 11 through the proximal end of the outer tube 12, and it can be freely moved in the interior of the outer tube 12 in the axial direction of the outer tube 12 by a moving means such as an actuator 24 in order to support the plug member 11 by so-called cantilever supporting.

Four (for example) ball-receiving holes 22a are provided in predetermined locations of the tubular holding body 22, and a ball 26 fits into each of these ball-receiving holes 22a. The balls 26 have dimensions which allow them to be able to engage with the circumferential groove 12a provided in the inner peripheral surface of the outer tube 12. The balls 26 are housed in the ball-receiving holes 22a so as not to protrude outwards from the outer peripheral surface of the tubular holding body 22.

In the embodiment shown in FIG. 2, a conical cap 22b which can fit into the positioning recess 13a provided in the above-described shuttle 13 is attached to the tip (distal end) of the tubular holding body 22. It ensures positioning of the tubular holding body 22 with respect to the plug member 11.

The rod 23 is disposed inside the tubular holding body 22. The rod 23 can be moved inside the tubular holding body 22 with respect to the tubular holding body 22 in its axial direction by a moving means such as an actuator 25. The distal end portion 23a of the rod 23 has a conical shape with an outer diameter which decreases from the proximal end towards the distal end.

First, the tubular holding body 22 is moved with respect to the outer tube 12 by operating an actuator 24 until the ball-receiving holes 22a provided in the tubular holding body 22 are aligned with the circumferential groove 12a provided in the outer tube 12. Next, the rod 23 is moved with respect to the tubular holding body 22 which is moved and stopped as described above by operating an actuator 25 until the conical end portion 23a of the rod 23 contacts the balls 26. As a result, the balls 26 are made to protrude outwards from the outer peripheral surface of the tubular holding body 22. This causes the balls 26 to engage with the circumferential groove 12a, whereby the tubular holding body 22 and the outer tube 12 are connected to each other.

With the tubular holding body 22 and the outer tube 12 connected in this manner, the rod 23 is moved backwards with respect to the tubular holding body 22 to move the conical end portion 23a of the rod 23 away from the balls 26, and the balls 26 are caused to fit into the ball-receiving holes 22a, thereby releasing the connection between the tubular holding body 22 and the outer tube 12.

As shown in FIG. 3 and FIG. 4, in this embodiment, a stopper 27 is disposed forward of the plug member 11 having the outer tube 12 connected to the tubular holding body 22. By abutting thereon the end surface of an oil country tubular good P in which the plug member 11 is to be mounted, the stopper 27 simultaneously carries out alignment of the plug member 11 and the oil country tubular good P and mounting (placement) of the plug member 11 with respect to the oil country tubular good P. As shown in FIG. 4, the stopper 27 has the shape of a diamond in which adjoining vertices have different angles and in which the corners are rounded so that alignment (axial alignment) of an oil country tubular good P and the tubular holding body 22 can be carried out even when there is deviation of the center at the end of the oil country tubular good P from the center of the tubular holding body 22 due to bending or the like of the tubular good P.

The stopper 27 is supported by an actuator 28. The cycle time required for positioning of an oil country tubular good P at the time of mounting of a plug member 11 can be further decreased if the actuator 28 is operated to position the stopper 27 in a predetermined position.

29 a-29d in FIG. 3 and FIG. 4 are shock absorbers which support the stopper 27. They absorb shocks when an oil country tubular good P strikes the stopper 27 at the time of positioning of the oil country tubular good P.

In the prior art with an apparatus such as a lathe including a plug member mounting and dismounting device, in a preliminary step before a plug member is inserted into a long pipe, the long pipe is first transported in its lengthwise direction into the plug member mounting and dismounting device, and then after the pipe is positioned in its lengthwise direction, the plug member is mounted in the pipe. At this time, a positioning stopper has to be operated by a cylinder from a direction other than the direction of transport of the pipe (such as from above or below) due to the presence of the plug member mounting and dismounting device which is positioned to the rear of the stopper in the lengthwise direction of the pipe (on the opposite side from the direction of transport of the pipe).

Accordingly, the length of operational movement of the cylinder is necessarily long and hence considerable time is required for taking in and out of the stopper. Furthermore, at the time of positioning of the pipe, an external force acts on the stopper in a different direction from the direction of operation due to impact with the pipe, and positional deviation of the stopper or equipment malfunctions frequently occurred.

In contrast, in this embodiment, a stopper 27, which performs positioning of an oil country tubular good P in which a plug member 11 is to be mounted on the end by causing it to abut on the end surface of the tubular good P, is disposed forward of the plug member 11 which is connected to the tubular holding body 22 in a state combined with the plug member mounting and dismounting device 21. Therefore, the time required for taking in and out of the stopper 27 by a cylinder or the like can be omitted. Furthermore, the stopper 27 is not moved in a direction other than the direction of transport of an oil country tubular good P. Accordingly, an external force due to impact with an oil country tubular good P at the time of positioning does not act on the stopper 27, and it is difficult for malfunctions and the like of the stopper 27 to take place.

Next, mounting of a plug member 11 according to the present invention in an end of an oil country tubular good P by a plug member mounting and dismounting device 21 according to the present invention will be explained.

First, after positioning of an oil country tubular good P is carried out, the vicinity of the end of the oil country tubular good P is supported by a floating chuck or the like with the axis of the portion of the pipe end which is to undergo working aligned with the rotational axis of the main shaft of a lathe. As a result, the axes of the pipe and an inside plug are aligned. The plug member 11 and the plug member mounting and dismounting device 21 are connected as shown in FIG. 2 by inserting the tubular holding body 22 of the device 21 into the outer tube 12 of the plug member 11 until the ball-receiving holes 22a of the body 22 are aligned with the circumferential groove 12a of the outer tube 12 and in that state, then inserting the rod 23 into the tubular holding body 22 as described above.

Then, the actuator 24 is operated to advance the plug member mounting and dismounting device 21 which is connected to the plug member 11 such that the plug member 11 is inserted into the end portion of the oil country tubular good P as shown in FIG. 2.

After the plug member 11 is inserted, the tubular holding body 22 and the outer tube 12 are separated from each other by moving the rod 23 backwards with respect to the tubular holding body 22, whereby the connection between the plug member mounting and dismounting device 21 and the plug member 11 is released. The actuator 24 is then operated to move the plug member mounting and dismounting device 21 backwards while leaving the plug member 11 inside the oil country tubular good P, and the mounting and dismounting device is pulled out of the oil country tubular good P. Then, thread cutting is carried out on a predetermined portion of the oil country tubular good P.

After thread cutting is carried out in this manner, the plug member 11 is pulled out of the end of the oil country tubular good P by carrying out the opposite of the above-described operation.

The plug member 11 of this embodiment is mounted and dismounted by holding the interior of the plug member 11. Therefore, the problem of shavings produced by thread cutting becoming wrapped around the plug member 11 is completely eliminated.

In this embodiment, the plug member mounting and dismounting device 21 can carry out positioning of the oil country tubular good P and mounting and dismounting of the plug member 11 in the end of the oil country tubular good P just by forwards and backwards movements without performing rotational movement.

Claims

1. A plug member which is mounted inside an end portion of a pipe which is to undergo thread cutting, characterized by comprising an outer tube having a proximal end and a distal end a shuttle which is installed so as to be able to reciprocate inside the outer tube between the proximal end and the distal end, a cap which is mounted on the distal end of the outer tube to close off the opening of the distal end, and a shuttle biasing spring having one end secured to the cap and the other end secured to the shuttle,wherein the outer tube has a seal member which is provided on its outer peripheral surface and which forms a seal against the pipe, and a circumferential groove which is formed in the inner peripheral surface of the tube in the proximal end portion,the shuttle is disposed in a predetermined position inside the proximal end portion of the outer tube, andthe shuttle biasing spring produces a spring pressing force on the shuttle towards the proximal end when the shuttle moves from the predetermined position towards the distal end.

2. A plug member as set forth in claim 1 characterized in that the shuttle has a fitting portion for positioning formed on the end surface of the shuttle on the side of the proximal end.

3. A plug member mounting and dismounting device for mounting a plug member as set forth in claim 1 in a pipe or removing it from a pipe, characterized by comprising a tubular holding body which is disposed inside the outer tube so as to be able to move with respect to the outer tube in the axial direction of the outer tube, a rod which has a distal end portion with a conical shape which decreases in outer diameter from its proximal end towards its distal end and which is disposed inside the tubular holding body so as to be able to move with respect to the tubular holding body in the axial direction of the tubular holding body, and moving means for independently moving the tubular holding body and the rod,wherein the tubular holding body has ball-receiving holes in a predetermined position into which balls which can engage with the circumferential groove of the outer tube can fit so as not to protrude outwards from the outer peripheral surface of the tubular holding body, and when it is inserted into the outer tube through the proximal end of the tube, its distal end can contact the end surface of the proximal end of the shuttle, andthe rod can make the balls protrude outwards from the outer peripheral surface of the tubular holding body and engage with the circumferential groove to connect the tubular holding body and the outer tube by moving relative to the tubular holding body so as to contact its distal end portion with the balls, and it can release the connection between the tubular holding body and the outer tube by moving relative to the tubular holding body so as to retracting its distal end portion from the balls and let the balls fit into the ball-receiving holes.

4. A plug member mounting and dismounting device as set forth in claim 3 characterized by having a fitting portion which is formed on the distal end of the tubular holding body and which fits into a fitting portion for positioning formed on the end surface of the shuttle on the side of the proximal end.

5. A plug member mounting and dismounting device as set forth in claim 3 characterized by further having a stopper which is installed forward of the plug member having the outer tube connected to the tubular holding body, the stopper performing, by abutting thereon the end surface of a pipe in which the plug member is to be mounted, alignment of the plug member and the pipe and mounting of the plug member with respect to the pipe simultaneously.

6. A plug member mounting and dismounting device for mounting a plug member as set forth in claim 2 in a pipe or removing it from a pipe, characterized by comprising a tubular holding body which is disposed inside the outer tube so as to be able to move with respect to the outer tube in the axial direction of the outer tube, a rod which has a distal end portion with a conical shape which decreases in outer diameter from its proximal end towards its distal end and which is disposed inside the tubular holding body so as to be able to move with respect to the tubular holding body in the axial direction of the tubular holding body, and moving means for independently moving the tubular holding body and the rod,wherein the tubular holding body has ball-receiving holes in a predetermined position into which balls which can engage with the circumferential groove of the outer tube can fit so as not to protrude outwards from the outer peripheral surface of the tubular holding body, and when it is inserted into the outer tube through the proximal end of the tube, its distal end can contact the end surface of the proximal end of the shuttle, andthe rod can make the balls protrude outwards from the outer peripheral surface of the tubular holding body and engage with the circumferential groove to connect the tubular holding body and the outer tube by moving relative to the tubular holding body so as to contact its distal end portion with the balls, and it can release the connection between the tubular holding body and the outer tube by moving relative to the tubular holding body so as to retracting its distal end portion from the balls and let the balls fit into the ball-receiving holes.

7. A plug member mounting and dismounting device as set forth in claim 4 characterized by further having a stopper which is installed forward of the plug member having the outer tube connected to the tubular holding body, the stopper performing, by abutting thereon the end surface of a pipe in which the plug member is to be mounted, alignment of the plug member and the pipe and mounting of the plug member with respect to the pipe simultaneously.