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. A mounting and dismounting device 21 for mounting and dismounting a plug member 11 with respect to an oil country tubular good P. The plug member 11 comprises an outer tube 12 having seal portions 16 a and 16 b and a circumferential groove 12 a, a shuttle 13, a cap 14, and a shuttle biasing spring 15 secured to the cap 14 and the shuttle 13. The mounting and dismounting device 21 comprises a tubular holding body 22, a rod 23 which has a conical end portion 23 a and which is disposed so as to move inside the tubular holding body 22, and moving means 24 and 25 which allow the tubular holding body 22 and the rod 23 to independently move. The tubular holding body 22 has ball-receiving holes 22 a into which fit balls 26 which engage with the circumferential groove 12 a. The tubular holding body 22 is inserted into the outer tube 12 through the proximal end of the tube so as to make its tip contact the end surface of the shuttle on the side of the proximal end, and the rod 23 is moved relative to the tubular holding body 22 so as to contact its end portion 23 a with the balls 26 to make the balls 26 engage with the circumferential groove 12 a, thereby connecting the tubular holding body 22 and the outer tube 12. The rod is moved relative to the tubular holding body 22 to retract the end portion 23 a, thereby releasing the connection between the tubular holding body 22 and the outer tube 12.

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, and   the 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, 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.   
     
     
         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, 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.   
     
     
         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.