JP3265259B2 - Pipe fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint used for supplying a high-pressure fluid composed of gas or liquid to a cylinder or the like.

[0002]

2. Description of the Related Art Conventionally, in this type of pipe joint, FIG.
As shown in FIG. 6, a joint main cylindrical body 41 having a fluid passage 49 and a rear end side slidably fitted inside the distal end side of the joint main cylindrical body 41 and a seal ring 42 is attached to the connected pipe body. A cylindrical sealing piston 43 which is in contact with the
The center of the collar 44 is rotatably supported in the centrifugal centrifugal direction by a collar portion 44 formed at the tip of the first, and pivots in the centrifugal centrifugal direction to open and close.
A plurality of chuck pieces 45 for sandwiching the connected pipe body abutting on the sealing piston 43 are fitted on the outer periphery on the distal end side of the joint main cylindrical body 41, and the chuck pieces 45 are moved forward and centered on the inner circumferential surface thereof. Operating sleeve 46 that is pressed in the direction to lock the operating sleeve 46 in a closed state, an eccentric cam 47 that advances and retreats the operating sleeve 46, a rotating pipe that controls the eccentric cam 47, and a connected pipe body that is connected to the connected pipe body. And a cam operation / safety loop body 48 surrounding a cylinder or the like provided with a cylinder.

[0003]

However, according to the above-mentioned conventional pipe joint, when connecting with the pipe to be connected, the tip of the sealing piston 45 of the pipe joint is pushed by one hand to the tip of the pipe to be connected. It is necessary to perform an operation with both hands such as tilting the cam operation and safety loop body 48 with the other hand while hitting, and the connection work is troublesome.

Further, when a force is applied to the operation / safety loop body 48 in the upright state in the upright direction due to some factor at the time of connection and the operation / safety loop body 48 rises, the eccentric cam 47 rotates. As a result, the operation sleeve 46 is retracted to unlock the closed state of the chuck piece 45, whereby the connected pipe is released from being clamped by the chuck piece 45. As a result, a situation occurs in which the pipe joint vigorously comes off from the connected pipe body due to the internal pressure, so that there is a problem that the handling thereof must be carefully monitored.

An object of the present invention is to provide a highly secure pipe joint which can easily perform a connecting operation and can surely maintain a connected state.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a joint main body having a fluid passage therein and a rear end inside the joint main body having a fluid passage therein. A cylindrical sealing piston whose end sides are slidably fitted so that the fluid passages communicate with each other and which abuts on the distal end of the connected pipe via a seal ring; and the distal end of the joint main cylindrical body When the rear end is rotatably supported in the centrifugal direction in the concave portion formed on the inner surface, the front end rotates and opens and closes in the centrifugal direction, and when the front end rotates in the centrifugal direction, the sealing is performed. A plurality of chuck pieces which are engaged and fastened to the inner surface of the connected pipe body which is in contact with a piston; biasing means for biasing the distal ends of these chuck pieces in a centripetal direction; Is slidably fitted on the outer periphery of the An operating sleeve for retracting the ston, and a lock sleeve fitted to the outer periphery of the rear end side of the joint main cylinder to advance by receiving the fluid pressure in the joint main cylinder and to prevent the advanced operation sleeve from retracting. And a first and second ball through-holes provided radially through the joint main cylinder at different positions in the longitudinal direction of the joint main cylinder at positions opposed to the sealing piston. A first ball fitted movably in a centrifugal direction and locking the sealing piston in a retracted state, a second ball locking the operation sleeve in a retracted state, the operation sleeve and the joint main cylinder body Slideable between the distal end portion and the first ball to keep the sealing piston locked when the sealing piston is retracted. A sleeve, wherein the outer periphery of the sealing piston is provided with a chuck escape recess for allowing the distal end side of each of the chuck pieces to escape in a centripetal direction when the sealing piston retreats, and in a centripetal movement state when the sealing piston retreats. A ball control projection for preventing the sealing piston from advancing while hitting the first ball and holding the second ball in a centrifugally moving state; and centrifuging the tip end of each of the chuck pieces when the sealing piston advances. A centrifugal movement projection for moving the chuck; and a step portion for preventing the advancement of the operation sleeve by contacting the second ball in the centrifugal movement state when the operation sleeve is retracted. A space portion is formed between the main cylinder and the joint main cylinder. A through-hole is formed to communicate the intermediate portion with the fluid passage in the joint main cylinder, and further between the joint main cylinder and the sealing piston, between the operation sleeve and the lock sleeve, and between the joint main cylinder. A spring is interposed between the slide sleeve and the slide sleeve.

[0007] According to this configuration, when the operating sleeve is retracted against the elastic force of the spring, the sealing piston moves backward together. When the chuck centrifugal movement projection moves backward with the retraction movement of the sealing piston, the tip of each chuck piece moves in the centripetal direction by the urging force of the urging means in the centripetal direction, and fits into the chuck relief recess, and each chuck The diameter of the envelope formed by the tip of the piece becomes smaller. In this state, the first ball moves in the centripetal direction, and the front portion of the ball control projection of the sealing piston hits the first ball to hold the sealing piston in the retracted state. Further, in this state, the second ball hits the rear portion of the ball control projection and moves centrifugally, hits the step portion of the operation sleeve against the second ball, and the operation sleeve is held in the retracted state. This state is a standby state of the pipe joint.

At the time of connecting the connected pipes, the tip of each chuck piece in a standby state is inserted into the connected pipes, and the tip of the spring holder is pressed against the connected pipes.
The spring holder comes into contact with the slide sleeve, the slide sleeve moves backward, the pressing of the first ball is lost, and the first ball moves centrifugally by operation of the ball control projection, whereby the sealing piston becomes free. To move forward. As the sealing piston advances, the packing at the tip hits the step in the connected pipe, and the chuck centrifugally moves as the sealing piston advances. Is engaged with the inner surface of the connected pipe body. Thereby, the connected pipes are reliably connected. Further, with the advance movement of the ball control projection accompanying the advance movement of the sealing piston, the support in the centripetal direction of the second ball is lost, and the second ball moves centripetally, whereby the operation sleeve becomes free and the spring is attached. Move forward by force.

When a high-pressure fluid flows through the fluid passage in the connected state, the high-pressure fluid flows into a space formed between the joint main cylinder and the lock sleeve through a through hole formed in the joint main cylinder. The lock sleeve moves forward under the pressure of the high-pressure fluid, contacts the rear end of the operating sleeve in the advanced position, prevents the operating sleeve from retreating, and locks the operating sleeve in that position.

[0010]

1 to 4 show an embodiment of a pipe joint according to the present invention. FIG. 1 is a partially cutaway plan view of the pipe joint, and FIG. FIG. 3 is an upper half longitudinal sectional side view showing a connection state of the pipe joint of the present example, and FIG. 4 is a connection state of the pipe joint of the present example and locked, showing a standby state of the pipe joint. FIG. 4 is a vertical sectional side view of an upper half portion showing a state where the upper half is vertical.

The pipe joint includes a main joint body 2 having a fluid passage 1 therein. An adapter 3 connected to a high-pressure fluid supply source (not shown) is connected to a base end of the joint main cylinder 2, and a fluid passage 4 in the adapter 3 is communicated with the fluid passage 1 of the joint main cylinder 2. ing. A rear portion of a cylindrical sealing piston 6 is axially slidably accommodated in a piston accommodation hole 5 on the distal end side in the joint main cylinder 2, and a fluid passage 7 penetrating through the axis of the sealing piston 6. Are connected to the fluid passage 1 of the joint main cylinder 2. Seal ring (O-ring) on the outer periphery of the tip of the sealing piston 6
8, the tip of the sealing piston 6 is connected to the step 9 a in the connected pipe 9 via the seal ring 8.
Is to be abutted. Between the joint main cylinder 2 and the sealing piston 6, a coil spring 10 that elastically urges the distal end of the sealing piston 6 in a direction protruding from the distal end of the joint main cylinder 2 is elastically interposed. A space between the rear outer periphery of the sealing piston 6 and the inner periphery of the joint main cylinder 2 is sealed by a seal member 11 (in the present embodiment, an O-ring and a backup ring).

The rear ends of a plurality of (six in this embodiment) chuck pieces 12 are rotatably supported in a centrifugal direction in recesses 2a formed in the inner periphery of the distal end of the joint main cylinder 2. ing. In this state, each chuck piece 12 opens and closes by rotating its tip side in the centrifugal direction, and in a standby state, the centrifugal direction by the urging means 13 composed of an O-ring (or a coil spring band) supported on the outer surface. Has been energized. Also,
In this standby state, each chuck piece 12 is fitted in a chuck relief recess 6a provided on the outer periphery of the distal end side of the sealing piston 6 as shown in FIG. The radius of the envelope formed by the outer circumference of the distal end side of the pipe 12 is reduced, and the pipe can be easily inserted into the connected pipe 9. These chuck pieces 1
2 is rotated in the centrifugal direction by a chuck centrifugal movement protrusion 6b provided on the outer periphery of the sealing piston 6 when the sealing piston 6 moves forward, and engages with the inner surface of the connected pipe 9 as shown in FIG. It is supposed to be. Male screw 12a is provided on the outer surface on the tip side of each chuck piece 12.
A male screw 12 is provided on the inner peripheral surface of the distal end of the connected pipe 9.
a is provided with a female screw portion 9b meshing with the male screw 1a.
An engaging portion 14 as shown in FIGS. 3 and 4 is constituted by the 2a and the female screw portion 9b. On the surface of the tip of the chuck piece 12 facing the sealing piston 6, a projection 12b substantially equal to the height of the chuck centrifugal movement projection 6b is provided. Therefore, in a state where the outer surface on the distal end side of each chuck piece 12 is engaged with the inner peripheral surface of the distal end of the connected pipe body 9, the outer surface on the distal end side of each chuck piece 12 is connected as shown in FIGS. The body 9 can be meshed in a state parallel to the inner peripheral surface of the tip.

An operation sleeve 15 is provided on the outer periphery of the main joint body 2.
Are slidably fitted. This operation sleeve 1
As shown in FIG. 1, the sealing piston 6 and the sealing piston 6 are connected to each other by a connecting screw 17 that penetrates a long hole 16 provided at a target position along the axial direction with the joint main cylinder 2. Can be separated from the connected pipe body 9 by retreating the operation sleeve 15.

A ring-shaped holder 18 is fixed to the outer periphery of the operation sleeve 15, and the ring-shaped holder 18 surrounds a head portion 20 such as a cylinder 19 having a connected pipe 9 as shown in FIG. The loop body 21 is rotatably connected.

A concave portion 2b is provided on the outer periphery of the rear end side of the joint main cylindrical member 2 in a required length in the axial direction. A cylindrical member 23 is fitted into the concave portion 2b and is prevented from coming off by a stop ring 24. I have. The cylindrical member 23 has a small outer diameter portion 23a on the front end side having the same diameter as the joint main cylindrical body 2, and a small outer diameter portion 23a on the rear end side.
It has a larger outer diameter portion 23b with a larger diameter, and a step portion 23c is provided at a boundary between the two. Joint main cylinder 2 and cylinder member 2
3 are sealed by a seal member 25 (in this embodiment, an O-ring and a backup ring).

A lock sleeve 26 is fitted over the cylinder member 23 and the joint main cylinder 2 so as to be slidable in the axial direction. The front side of the lock sleeve 26 has a small inner diameter hole 26a so as to fit into the small outer diameter portion 23a of the cylindrical member 23 so as to be slidable, and the rear side has a large outer diameter portion 2 of the cylindrical member 23.
A large inner diameter hole 26b is provided so as to fit into and slide on 3b, and a medium inner diameter hole 26c is provided at the boundary between the two. A space 27 is formed between the lock sleeve 26 and the cylindrical member 23 due to the presence of the inner bore 26c. The outer peripheral side of the lock sleeve 26 has a small outer diameter section 26d on the front side, a large outer diameter section 26e on the rear side, and a middle outer diameter section 26f between them. Small outer diameter portion 26d, middle outer diameter portion 26f, and large outer diameter portion 26
The boundary with e is a step. The space between the lock sleeve 26 and the cylindrical member 23 is sealed by a seal member 28 (in the present embodiment, constituted by an O-ring and a backup ring). Also, the large outer diameter portion 2 of the lock sleeve 26
On the outer peripheral surface of 6e, a display portion 37 (coloring in this embodiment) for confirming the movement of the lock sleeve 26 is provided.

The joint main cylinder 2 and the cylinder member 23 have through holes 2 for communicating the fluid passage 1 of the joint main cylinder 2 with the space 27.
9 and 29 are formed.

At the rear of the operating sleeve 15, a small outer diameter hole 15a fitted on the outer periphery of the joint main cylinder 2, and a middle outer diameter hole 15b fitted on the outer periphery of the middle outer diameter 26f of the lock sleeve 26 are provided.
And a large outer diameter hole portion 15c that fits around the outer periphery of the large outer diameter portion 26e of the lock sleeve 26.

Between the lock sleeve 26 and the operation sleeve 15, a coil spring 30 for urging the operation sleeve 15 toward the distal end where the chuck piece 12 exists is elastically interposed. The operating sleeve 1 is biased by the coil spring 30 between the joint main cylinder 2 and the operating sleeve 15.
Stoppers 2c, 15d for regulating the forward movement range
Is provided.

At the position facing the sealing piston 6, the joint main cylinder 2 penetrates its thickness in the radial direction at different positions in the longitudinal direction, and passes through the first and second ball through holes 2 d, 2 d.
2e are provided in plurality. In these first and second ball through holes 2d and 2e, there are provided a first ball 31 for locking the sealing piston 6 in the retreat state and a second ball 32 for locking the operation sleeve 15 in the retreat state.
Are movably fitted in the ball centrifugal direction. The operation sleeve 15 is provided with a stepped portion 15e so as to be locked by the second ball 32 in the retreat state.

When the sealing piston 6 is retracted as shown in FIG. 2, the ceiling piston 6 prevents the ceiling piston 6 from advancing by hitting the first ball 31 which is in a centripetal movement state and is in a centrifugal movement state. 2
Ball control projection 6c for holding the ball 32 is provided. The front surface of the ball control projection 6c (chuck piece 1)
The rising surface on the side where 2 exists) is an inclined surface that gradually rises from the front to the rear. The falling surface on the rear surface of the ball control projection 6c is an inclined surface that gradually decreases from the front to the rear.

A slide sleeve 33 is slidably interposed between the operating sleeve 15 and the distal end portion of the joint main cylinder 2. The slide sleeve 33 is provided with a ball pressing portion 33a at a rear portion for maintaining a state in which the first ball 31 locks the sealing piston 6 when the sealing piston 6 is retracted. Further, the slide sleeve 33 is provided with a ball escape recess 33b that allows the first ball 31 to move centrifugally.
The slide sleeve 33 is a coil spring 3 resiliently interposed between the distal end of the joint main cylinder 2 and a spring holder 34 supported on the distal end of the slide sleeve 33.
5, the operation sleeve 15 is urged to protrude outward from the distal end thereof. The spring holder 34 has an annular shape and is slidably fitted in the slide sleeve 33 in the axial direction. The spring holder 34 is stopped by the slide sleeve 33 by a stop ring 36 so as not to come off from the slide sleeve 33. .

Next, from such a pipe joint, the connected pipe 9
The operation of filling the cylinder 19 with the fluid will be described.

In such a pipe joint, when the operating sleeve 15 is retracted from the state shown in FIG. 3 against the resilience of the spring 30, the sealing piston 6 is moved backward together with the connecting screw 17.

When the chuck centrifugal movement protrusion 6b moves backward with the backward movement of the sealing piston 6, the tip of each chuck piece 12 moves in the centripetal direction by the urging of the urging means 13 in the centripetal direction. As shown in the figure, the envelope fits into the chuck escape recess 6a, and the diameter of the envelope formed by the tip of each chuck piece 12 is reduced. In the state shown in FIG.
The ball 31 moves in the centripetal direction, and the front portion of the ball control projection 6c of the sealing piston 6 hits the first ball 31 to hold the sealing piston 6 in a retracted state. Further, in this state, the second ball 32 hits the rear portion of the ball control projection 6c and moves centrifugally to cause the second ball 32 to move.
The stepped portion 15e of the operation sleeve 15 hits the ball 32, and the operation sleeve 15 is held in the retreated state. The state shown in FIG. 2 is a standby state of the pipe joint.

At the time of connection of the connected pipes 9, the tips of the chuck pieces 12 in the standby state are inserted into the connected pipes 9 to resist the elastic force of the coil spring 35 as shown in FIG. And the tip of the spring holder 34 is connected to the pipe 9 to be connected.
, The rear end of the spring holder 34 comes into contact with the inner peripheral step of the slide sleeve 33, and the slide sleeve 33 moves backward, and the first ball 31 is no longer held down. The centrifugal movement is performed by the operation of the inclined surface of the control projection 6c.
Becomes free and moves forward. Sealing piston 6
The seal ring (O-ring) 8 at the distal end thereof abuts on the step 9a in the connected pipe 9, and the chuck centrifugal movement projection 6b moves forward with the sealing piston 6 to move each chuck piece 12 forward. The distal end moves in the centrifugal direction, and the male screw portion 12 on the outer surface of the distal end of each of the chuck pieces 12 is moved.
a is engaged with the female screw portion 9b on the inner surface of the connected pipe 9 and fastened. Thereby, the connected pipe 9 is securely connected. Further, with the advance movement of the ball control projection 6c accompanying the advance movement of the sealing piston 6, the support of the second ball 32 in the centripetal direction is lost, and the second ball 32 moves in the centripetal direction. It becomes free and moves forward by the bias of the spring 30. As shown in FIG. 3, the operation of the operation sleeve 15 stops when the stopper portion 15 d comes into contact with the stopper portion 2 c of the joint main cylinder 2.

The safety loop body 21 is connected to the pipe 9 at a position convenient for connecting the pipe 9 to be connected, for example, a high-pressure hose (not shown) connected to the adapter 3. After being connected to the cylinder 19, the head 20 is surrounded by falling down to the cylinder 19 side.

When the connection state is established, the cock of the high-pressure fluid supply source (not shown) is opened, and the fluid passage 4 of the adapter 3 is opened.
When the high-pressure fluid flows through the joint main cylinder 2, the high-pressure fluid flows into the fluid passage 1 of the joint main cylinder 2, and passes between the joint main cylinder 2 and the lock sleeve 26 through a through hole 29 formed in the joint main cylinder 2. The high-pressure fluid flows into the space 27 formed therebetween, and the lock sleeve 26 moves forward as shown in FIG. 4 under the pressure of the high-pressure fluid, and abuts on the rear end side of the operation sleeve 15 in the advanced position. , To prevent the operation sleeve 15 from retreating,
The operating sleeve 15 is locked in that position. At this time, since the display portion 37 on the surface of the lock sleeve 26 is hidden inside the rear end of the operation sleeve 15, the lock sleeve 26
Movement can be confirmed. Therefore, the filling operation of the cylinder 19 with the high-pressure fluid can be performed safely.

When the operation of filling the high-pressure fluid is completed, the cock on the cylinder 19 side is closed, and the cock on the high-pressure fluid supply source is closed on the supply side to stop the supply of the high-pressure fluid to the fluid passage 4 of the adapter 3. By operating the pressure reducing valve on the source side to release the residual pressure of the high-pressure fluid in the space portion 27, the force of the spring 30 returns to a state where it has won, and the lock sleeve 26 returns to the original standby position as shown in FIG. Return.

Returning to the state shown in FIG. 3, the operation sleeve 15 is opposed to the elastic force of the spring 30 as described above.
Is retracted, and the presence of the connecting screw 17 allows the sealing piston 6 to be moved backward together, thereby returning to the standby state shown in FIG. When the state shown in FIG. 2 is reached, the distal end of each chuck piece 12 rotates in the centripetal direction and separates from the connected pipe 9, and the connection to the connected pipe 9 is released.

[0031]

As described above, according to the pipe joint according to the present invention, in connection with the connected pipe, the connection operation is not performed in conjunction with the safety loop body, but simply by the connected pipe. The connection and disconnection can be performed easily by one-touch operation such as pressing against the body and simply retreating the operation sleeve for separation, and special operation for locking the operation sleeve in the connected state Therefore, it is possible to automatically lock the operation sleeve by utilizing the pressure of the fluid in the flow path without performing the above, so that a highly secure pipe joint can be obtained. In addition, since the connection operation is performed without interlocking with the safety loop body, the connection may be disconnected even if a force in the upright direction is applied to the safety loop body that has been tilted down for some reason. Is safe.

[Brief description of the drawings]

FIG. 1 is a partially broken plan view showing an example of an embodiment of a pipe joint according to the present invention.

FIG. 2 is an upper half vertical sectional side view showing a standby state of the pipe joint of the present embodiment.

FIG. 3 is an upper half vertical sectional side view showing a connection state of the pipe joint of the present example.

FIG. 4 is a longitudinal sectional side view of an upper half showing a connected state and a locked state of the pipe joint of the present example.

FIG. 5 is a vertical sectional side view of an upper half showing a posture of each part in a connection state of a conventional pipe joint.

FIG. 6 is a partially broken plan view of a conventional pipe joint.

[Explanation of symbols]

 Reference Signs List 1 fluid passage 2 joint main cylinder 2a, 2b recess 2c stopper 2d, 2e first and second ball through holes 3 adapter 4 fluid passage 5 piston accommodation hole 6 sealing piston 6a chuck relief recess 6b chuck centrifugal movement projection 6c Inner bore 7 Fluid passage 8 Seal ring (O-ring) 9 Connected pipe 9a Step 9b Female thread 10 Coil spring 11 Seal member 12 Chuck piece 12a Male thread 12b Protrusion 13 Urging means 14 Occlusal section 15 Operation sleeve 15a Small outer diameter hole 15b Medium outer diameter hole 15c Large outer diameter hole 15d Stopper 15e Step 16 Long hole 17 Connecting screw 18 Ring holder 19 Cylinder 20 Head 21 Safety loop body 23 Tube member 23a Small outer diameter 23b Large outer diameter portion 23c Step portion 24 Stop ring 25 Seal member 6 Lock sleeve 26a Small inner diameter hole 26b Large inner diameter hole 26c Medium inner diameter hole 26d Small outer diameter part 26e Large outer diameter part 26f Medium outer diameter part 27 Space 28 Seal member 29 Through hole 30 Coil spring 31, 32 First, Second ball 33 Slide sleeve 33a Ball holding portion 33b Ball escape recess 34 Spring holder 35 Coil spring 36 Stop ring 37 Display

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16L 37/22

Claims (1)

(57) [Claims] A coupling main cylinder having a fluid passage therein;
A fluid passage is provided inside, and the rear end side is slidably fitted inside the distal end side of the joint main cylinder so that the fluid passages are communicated with each other, and at the distal end of the connected pipe via a seal ring. The distal end pivots in the centrifugal direction while the rear end is rotatably supported in the centrifugal centrifugal direction in the cylindrical sealing piston to be contacted and the concave end formed in the inner surface of the distal end of the joint main cylinder. A plurality of chuck pieces that are engaged and fastened to the inner surface of the connected pipe body that is in contact with the sealing piston when the tip side rotates in the centrifugal direction, and the tip sides of these chuck pieces. Biasing means biasing in a centripetal direction;
An operating sleeve that is slidably fitted to the outer periphery of the joint main cylinder and that retreats the sealing piston at the time of separation; A lock sleeve that moves forward by receiving the fluid pressure and prevents the advanced operation sleeve from retreating, and the joint main cylinder body at a position facing the sealing piston is different in position in the longitudinal direction and has a different thickness. A first ball and the operation sleeve, which are movably fitted in the ball centrifugal direction in first and second ball through holes provided to penetrate in the radial direction and lock the sealing piston in a retreated state, are provided. A second ball that locks in a receded state;
A slide sleeve that is slidable between a distal end portion of the operating sleeve and the joint main cylinder body and that holds a state in which the first ball locks the sealing piston when the sealing piston is retracted; Wherein the sealing piston has, on its outer periphery, a chuck escape recess for allowing the tip side of each chuck piece to escape in a centripetal direction when the sealing piston retreats, and the centrifugal movement state when the sealing piston retreats. A ball control projection for preventing the sealing piston from advancing while hitting a first ball and holding the second ball in a centrifugally moving state; and causing the distal end side of each of the chuck pieces to centrifugally move when the sealing piston advances. A chuck centrifugal movement projection is provided, and in the operation sleeve, A step portion is provided for hitting the second ball in the centrifugally moving state during the retreat state and preventing the ball from advancing, a space is formed between the lock sleeve and the joint main cylinder, and the joint main cylinder is formed. A through-hole is formed in the cylinder to communicate this space with the fluid passage in the joint main cylinder, and between the joint main cylinder and the sealing piston, between the operation sleeve and the lock sleeve, and A pipe joint, wherein springs are elastically interposed between the joint main cylinder and the slide sleeve, respectively.