JP2000352489A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance controllability by enabling a movable locking piece to move back radially outwards from a locking groove to allow removal of a plug, and enabling the plug to be connected simply by insertion of the plug into an inner cylinder and by displacement of the inner cylinder in the same backward direction as the direction of insertion. SOLUTION: When a plug P is inserted into an inner cylinder 23 and displaced backwards, an outer cylinder 33 is released from a control ball 22 (movable control piece) and displaced forwards and a lock ball 29 (movable locking piece) is pushed radially inward by the outer cylinder 33 and held in engagement state with a locking groove 10 to thereby lock the plug P in a connected state. When the outer cylinder 33 is displaced backwards from the connected state, the inner cylinder 23 is released from the control ball 22 and displaced forwards and the lock ball 29 is released from the state of being held by the outer cylinder 33 into an unlocked state in which it can move back radially outwards from the locking groove 10 to allow removal of the plug P. The plug P can be connected simply by inserting and pushing the plug P into the inner cylinder 23 without the need for the outer cylinder 33 to be displaced to the unlocked position, so that controllability is good.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to connection and piping of refrigerant gas filling equipment for cooling / heating air conditioners, equipment for evacuation, equipment for water supply such as water supply and hot water supply for houses, and equipment for fluid supply such as gas piping. At this time, the present invention relates to a pipe joint in which connection and disconnection with a counterpart pipe member can be performed with one touch.

[0002]

2. Description of the Related Art In connection and piping of various types of fluid equipment, a component called a plug and a component called a socket are fixed to ends of a pipe member to be connected, respectively, and a plug is inserted in a socket. A means for connecting the two pipe members by inserting them into the pipe member is used. Some plugs are widely available on the market, and are distributed as a kind of reference product. Currently, socket manufacturers manufacture products that match the shape and dimensions of the plug. One such socket is shown in FIGS.

The plug 1 has a cylindrical shape as a whole, and a circumferential lock groove 2 is formed at the center in the longitudinal direction of the outer circumference, and a sealing surface 3 is formed in a region forward of the lock groove 2. . On the other hand, the socket 4 holds the lock ball 6 at the front end of the joint body 5 so as to be displaceable in the radial direction.
And a spring 8 for urging the outer cylinder 7 forward, and the outer cylinder 7 is always urged by the spring 8. Moves forward, and holds the lock ball 6 in a state of protruding inward. When the plug 1 is connected, the lock ball 6 is placed in a free state in which the lock ball 6 can be displaced outward by sliding the outer cylinder 7 backward against the spring 8, and the plug 1 is placed in the socket 4 while maintaining that state. And release the outer cylinder 7. Then, the outer cylinder 7 is moved forward by the urging of the spring 8 to push the lock ball 6 inward, and the lock ball 6 is engaged with the lock groove 2 of the plug 1, whereby the plug 1
And the socket 4 are locked in the connected state. Further, when the plug 1 is removed, if the outer cylinder 7 is slid backward, the lock ball 6 enters an unlocked state in which the lock ball 6 can be retracted from the lock groove 2, so that the plug 1 may be pulled out as it is.

[0004]

The above conventional socket 4
When the plug 1 is connected, it is necessary to hold the outer cylinder 7 in the unlocked state in which the outer cylinder 7 has been slid against the bias of the spring 8, so that the operability is poor. The present invention has been made in view of the above circumstances, and aims to improve operability at the time of connection.

[0005]

According to the first aspect of the present invention, a lock groove is formed on the outer periphery, and the outer periphery of the lock groove is connected to a cylindrical plug whose outer periphery is a sealing surface. A pipe joint, which has a cylindrical joint body, a movable control piece provided in the joint body so as to be displaceable in a radial direction, and the plug can be inserted from the front, and with respect to the joint body. An inner cylinder fitted in the axial direction displaceably and urged forward, a movable lock piece provided in the inner cylinder so as to be displaceable in the radial direction, and the movable lock piece on the inner circumference of the inner cylinder. A lock member, which is also mounted rearward and includes a seal member that can be brought into close contact with the seal surface, and an outer cylinder that is axially displaceably fitted to the joint body and is urged forward. In the state, the inner cylinder is engaged with the movable control piece. Is held in the rear position against the biasing force,
The outer cylinder is displaced forward in accordance with the bias and holds the movable control piece in an engaged state with the inner cylinder, and the movable lock piece is held in an engaged state with the lock groove by the outer cylinder, In the unlocked state, the outer cylinder is held at the rear position against the bias by engagement with the movable control piece, and the movable control piece is moved outward by the inner cylinder being displaced forward in accordance with the bias. The movable lock piece is held in the engagement state with the cylinder, the movable lock piece is released from the holding by the outer cylinder, and can be retracted outward from the lock groove.

According to a second aspect of the present invention, in the first aspect of the invention, the plug is inserted into the inner cylinder until the lock groove and the sealing surface thereof correspond to the movable lock piece and the seal member, respectively. Sometimes, a configuration is provided in which a restricting portion for restricting the plug from being inserted further is provided. According to a third aspect of the present invention, in the first or second aspect of the invention, in the process of rearward displacement of the inner cylinder accompanying insertion of the plug into the inner cylinder, the outer cylinder is moved forward by the movable control piece. Before being released from the regulation, the movable lock piece is held in an engagement state with the lock groove by the outer cylinder. The invention of claim 4 is claim 1
The invention according to any one of claims 3 to 3, wherein a lock release cylinder having a port in the joint body secures an air chamber communicating with the port between an inner periphery thereof and an outer periphery of the joint body, and a front-rear direction. The unlocking cylinder is displaced rearward by the pressure of the air supplied to the air chamber, and the unlocking cylinder is displaced rearward when the unlocking cylinder is displaced rearward. Is configured to push the outer cylinder rearward.

[0007]

When connecting the plug, when the plug is inserted into the inner cylinder from the front in the unlocked state and the inner cylinder is displaced rearward with respect to the joint body, the outer connection is made. The cylinder is released from holding by the movable control piece and is displaced forward, and the outer cylinder displaced forward pushes the movable control piece inward in the radial direction and engages with the inner cylinder to hold the inner cylinder at the rear position. I do. Further, the movable lock piece is pushed inward in the radial direction by the outer cylinder and held in the engaged state with the lock groove, and the plug is locked in the connected state by the engagement between the movable lock piece and the lock groove. Furthermore, the connection part with a plug is waterproofed because a sealing member adheres to a sealing surface.

When the plug is removed, when the outer cylinder is displaced rearward against the bias, the inner cylinder is released from being held by the movable control piece and is displaced forward, and the inner cylinder displaced forward is moved. The outer cylinder is held at the rear position by pushing the piece radially outward to engage the outer cylinder. Further, the movable lock piece is released from being held by the outer cylinder and can be retracted radially outward from the lock groove, so that the plug can be pulled out. When connecting the plug, it is not necessary to displace the outer cylinder in advance and release the lock, and it is only necessary to insert the plug into the inner cylinder and displace the inner cylinder in the same backward direction as the insertion direction. Excellent.

[Invention of claim 2] When the plug is inserted into the inner cylinder, after the lock groove and the sealing surface are inserted to positions corresponding to the movable lock piece and the seal member, respectively, the plug and the inner cylinder are regulated by the restricting portion. As a whole, it is displaced in the insertion direction, that is, in the rearward direction with respect to the joint main body, and directly reaches the locked state.
The position of the movable lock piece and the lock groove and the position of the seal member and the seal surface do not shift during the connection operation. [Invention of Claim 3] When the outer cylinder is released from the movable control piece, the outer cylinder is vigorously displaced forward according to the urging. At this time, the movable lock piece is pushed radially inward by the outer cylinder. Therefore, it is possible to prevent the outer cylinder from interfering with the movable lock piece protruding radially outward. [Invention of claim 4] At the time of unlocking, it is only necessary to supply air to the air chamber, so that no manual operation is required and the burden on the operator is reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of the present invention will be described below with reference to FIGS. In the manufacturing process of the cold air conditioner, the pipe joint S of this embodiment is connected to a refrigerant gas filling device, a vacuum evacuation device, a pressure resistance test device, and an airtightness test device with respect to a heat exchanger of the air conditioner, Piping such as refrigerant pipes, water pipes from homes and water heaters in houses, kitchens, bathrooms,
Used for plumbing around water to supply water or hot water to washrooms, or to supply hot water to hot water pipes stretched for floor heating, etc.One-touch attachment and detachment with pipe members on the other side It is something that can be done in.

First, a plug P which is a connection partner of the pipe joint S of the present embodiment will be described. The plug P is widely available on the market and is distributed as a kind of reference product. The plug P has no tubular shape as a whole, and a circumferential lock groove 10 having a trapezoidal cross section in which both front and rear sides are tapered is formed at the center of the outer periphery in the length direction. In addition, a region of the outer periphery that is forward of the lock groove 10 (to the right in FIGS. 1 to 4) has substantially the same outer diameter as the outer diameter of the groove bottom of the lock groove 10 and the outer diameter is the front end of the plug P The seal surface 11 is constant up to this point. still,
The area behind the lock groove 10 in the outer periphery is a hexagonal head 12
It has been. On the other hand, a female screw hole 13 for connecting a pipe (not shown) is formed at the rear end of the inner periphery of the plug P. A normally-closed on-off valve 14 is provided in the first half area of the inner periphery, and this on-off valve 14 is brought into an open state by abutting on an on-off valve 32 provided in the pipe joint S of the present embodiment.

Next, the pipe joint S of this embodiment will be described. The rear end portion of the cylindrical joint body 20 (FIGS. 1 to 4)
Female end 20A for connecting a pipe (not shown) is formed at a plurality of circumferentially spaced positions on the front end of the joint main body 20 at the inner periphery of the joint main body 20, respectively. A control holding hole 21 penetrating from the surface to the outer peripheral surface is formed, and each control holding hole 21 has a spherical control ball 22 having a diameter larger than the plate thickness of the joint main body 20 (a constituent element of the present invention). A certain movable control piece) is accommodated so as to be displaceable in the radial direction.

An inner cylinder 23 having a cylindrical shape is fitted on the inner periphery of the joint body 20 so as to be relatively movable in the axial direction (front-rear direction) and urged forward by a compression coil spring 24. . The gap between the outer peripheral surface of the inner cylinder 23 and the inner peripheral surface of the joint body 20 is sealed by an O-ring 25.
A circumferential outward locking groove 26 having a trapezoidal cross section formed by tapering both front and rear sides of the inner cylinder 23 is formed on the outer periphery of the inner cylinder 23, and is adjacent to the rear of the outward locking groove 26. The circumferential area is an outward pressing surface 27. Inner cylinder 2
1 and 4, the outward pressing surface 27 pushes the control ball 22 outward in correspondence with the control ball 22, as shown in FIGS. When the position 23 is in the forward position, as shown in FIGS. 2 and 3, the outward locking groove 26 allows the control ball 22 to move inward in correspondence with the control ball 22.

The front end of the inner cylinder 23 projects forward from an opening at the front end of the joint body 20, and the inner peripheral surface of the inner cylinder 23 is provided at a plurality of circumferentially spaced positions in this protruding portion. A lock holding hole 28 penetrating from the inner cylinder 2 to the outer peripheral surface is formed.
Rock ball 29 having a spherical shape with a diameter larger than the plate thickness dimension of No. 3
(Movable lock piece which is a component of the present invention) is accommodated so as to be displaceable in the radial direction. The opening on the inner peripheral surface side of the lock holding hole 28 is smaller in diameter than the lock ball 29, thereby preventing the lock ball 29 from being detached to the inner peripheral side. Further, a ring-shaped seal member 30 is mounted on the inner periphery rearward (backward) of the lock ball 29.

A plug P is inserted into the inner cylinder 23 from the front, and the inserted plug P has a stepped stopper 31 of the inner cylinder 23 at the front end face peripheral edge (in accordance with the constitutional requirements of the present invention). When the front end of the hexagonal head 12 abuts on the front end face 23A of the inner cylinder 23 (a restriction part which is a component of the present invention), the front end is stopped. The inner periphery of the front end portion of the inner cylinder 23 is formed into a shape corresponding to the outer peripheral shape of the plug P when the plug P is inserted to the front stop position. When the plug P is in the front stop position, the lock holding hole 28 and the lock ball 29 are formed. Correspond to the lock groove 10, and the sealing member 30 is in close contact with the rear end of the sealing surface 11.

The inner cylinder 23 is provided with a normally-closed open / close valve 32. When the plug P is inserted into the inner cylinder 23,
The on-off valves 14, 32 on both the plug P side and the inner cylinder 23 side abut each other, so that the valve is opened. A cylindrical outer cylinder 33 is fitted to the front end of the joint body 20 so as to be relatively movable in the axial direction (front-rear direction) and urged forward by a compression coil spring 34. Outer cylinder 33
A circumferentially inward locking groove 35 having a trapezoidal cross section in which both front and rear sides are inclined in a tapered shape is formed on the inner periphery of the rear end portion, and is adjacent to the rear of the inward locking groove 35. The circumferential area is an inward pressing surface 36, and the outer cylinder 33
A lock pressing surface 37 is formed on the inner periphery of the front end of the lock.

When the outer cylinder 33 is positioned rearward against the bias, the inward locking groove 35 allows the control ball 22 to move outward in correspondence with the control ball 22, as shown in FIG. When the outer cylinder 33 is at the front position, the inward pressing surface 36 pushes the control ball 22 inward in correspondence with the control ball 22, as shown in FIG. When the outer cylinder 33 is located at the rear and the inner cylinder 23 is located at the front, as shown in FIG. 4, the outward pressing surface 27 pushes the control ball 22 outward to inwardly engage the inward locking groove 3.
5 and the pressing surface 3 for locking.
7 retreats rearward from the lock ball 29 to allow radial displacement of the lock ball 29 to the outside. When the outer cylinder 33 is located forward and the inner cylinder 23 is located rearward, the inward pressing surface 36 pushes the control ball 22 inward as shown in FIG. , And the locking pressing surface 37 pushes the lock ball 29 inward to hold the lock ball 10 in the engaged state.

Next, the operation of the present embodiment will be described. With the plug P removed, the pipe joint S is in the unlocked state shown in FIG. In this unlocked state, the inner cylinder 2
3 is located forward, and its outward pressing surface 27 pushes the control ball 22 outward to hold it in engagement with the inward locking groove 35, thereby holding the outer cylinder 33 at the rear position. Thus, the lock ball 29 is released from the lock pressing surface 37 and is allowed to be displaced radially outward. In this state, when the plug P is inserted into the inner cylinder 23, the plug P comes to a stop at the front, the seal member 30 comes into close contact with the seal surface 11, and the lock ball 29 corresponds to the lock groove 10. When the insertion of the inner cylinder 23 is further continued from this state, the inner cylinder 23 is pushed back together with the plug P against the urging, and the outward locking groove 26 is thereby connected with the control ball 22. It is displaced to the corresponding state, in the process
As shown in (2), the outer cylinder 33 urged forward shifts forward while pushing the control ball 22 inward on the tapered surface of the inward locking groove 35.

Here, when the inward locking groove 35 of the outer cylinder 33 is completely disengaged from the control ball 22, the outer cylinder 33 moves vigorously forward by the urging of the press-connecting connector 34. At the previous stage, the outer cylinder 33 is slightly displaced forward while the inner cylinder 23 is displaced slightly rearward,
The lock pressing surface 37 is engaged with the lock ball 29 to prevent the lock ball 29 from being displaced radially outward (see FIG. 2). Thereby, the rock ball 2
Reference numeral 9 engages with the lock groove 10, and the plug P and the inner cylinder 23 are locked in the detachment restricted state.

When the inner cylinder 23 is continuously pushed in, the inward locking groove 35 is completely disengaged from the control ball 22. At the same time, the outer cylinder 33 moves forward with the urging force, Engagement ring 3 around the front end of cylinder 23
8, the forward displacement is regulated, and the locking pressing surface 37 of the outer cylinder 33 pushes the lock ball 29 to lock the lock groove 1.
Lock to the engaged state with 0. Further, the inward pressing surface 36 at the rear end of the outer cylinder 33 engages with the control ball 22 and
The inner cylinder 23 is locked at the rear position (see FIG. 3). With the above, the connection work of the plug P is completed. In addition, plug P
The gap between the inner cylinder 23 and the sealing surface 11 of the sealing member 30
Sealed by close contact with

When removing the plug P, the outer cylinder 33 is displaced rearward against the bias. Then, the control ball 22 is released from the engagement by the inward pressing surface 36 and is allowed to be displaced in the radial direction to the outside.
Is released from the forward displacement restricted state due to. Then, the inner cylinder 23 is urged forward by the urging force, and the outward pressing surface 27 of the inner cylinder 23 presses the control ball 22 outward to engage with the inward locking groove 35 of the outer cylinder 33. The outer cylinder 33 is locked at the rear position because it is held in the mated state. Also,
The lock ball 29 is released from the pressing state by the locking pressing surface 37, and is displaced radially outward, that is, the lock groove 1.
Since displacement in the direction of releasing engagement with 0 is allowed,
The plug P can be removed from the inner cylinder 23.

As described above, in the present embodiment, when connecting the plug P, it is not necessary to displace the outer cylinder 33 to the rear position in advance to release the lock, and insert the plug P into the inner cylinder 23. Therefore, only one action operation of pushing the inner cylinder 23 backward in the same direction as the insertion direction is required, so that the operability is excellent. In the process of inserting the plug P into the inner cylinder 23 and displacing the inner cylinder 23 backward, the outer cylinder 3
Before the lock ball 29 is released from the forward displacement restriction by the control ball 22 and displaced vigorously forward, the lock ball 29
Is formed by the locking pressing surface 37 of the outer cylinder 33.
When the outer cylinder 33 is vigorously displaced forward by the urging force, the lock pressing surface 37 only comes into sliding contact with the lock ball 29. Therefore, the lock ball 29 does not protrude outside the inner cylinder 23 and the front end of the outer cylinder 33 abuts on the protruding portion, and the forward displacement operation of the outer cylinder 33 is performed smoothly.

Incidentally, even in the case of a two-ball type pipe joint having a lock ball and a control ball as in the present embodiment,
In the case of a structure in which both of the two balls are provided on the joint body, there is a case where the outer cylinder starts sliding before the plug engages with the lock ball at the time of connection, so that the outer cylinder may rub against the lock ball. Also, at the time of unlocking, the plug may be pushed by the inner cylinder and moved before the lock ball is completely released from the outer cylinder, so that the plug and the lock ball may interfere with each other. On the other hand, in the pipe joint S of the present embodiment, the lock ball 29 is provided on the inner cylinder 23 and the control ball 22 is provided on the joint body 20.
During the connection operation and the unlocking operation of the plug P, the plug P and the inner cylinder 23 do not relatively move, and the lock ball 2
9 and the lock groove 10 can always maintain the corresponding positional relationship. Therefore, there is no possibility of causing interference such as rubbing between the lock ball 29 and the outer cylinder 33 and between the lock ball 29 and the plug P.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the unlocking means has a different configuration from that of the first embodiment. Other configurations are the same as those in the first embodiment, and thus the same configurations are denoted by the same reference numerals and description of the structures, operations, and effects will be omitted.
At the outer periphery of the joint body 20, two seal members 40, 41 are mounted at the front and rear of the outer cylinder 33 at the rear thereof, and the inner peripheral surface of the seal members 40, 41 is brought into close contact with the lock release. The cylinder 42 is fitted outside so as to be displaceable in the front-rear direction. A female screw-shaped port 43 is formed between the seal members 40 and 41 in the lock release cylinder 42 and communicates from the inner circumference to the outer circumference.
A supply pipe from a pressurized air supply source (not shown) is connected. In the area where the port 43 is formed, an air chamber 44 is formed between the inner circumference of the lock release cylinder 42 and the outer circumference of the joint body 20. The front end wall of the air chamber 44 is formed on the joint body 20 side, and the rear end wall is formed on the lock release cylinder 42 side. The inside of the air chamber 44 is kept airtight by the two seal members 40 and 41. Further, the unlocking cylinder 42
A stopper ring 45 made of a C-ring
The stopper ring 45 has an outer cylinder 3
The outer peripheral front edge of 3 is abutted from behind.

When the pressurized air is supplied from the port 43 to the air chamber 44 with the plug P connected, the lock release cylinder 42 is moved rearward with respect to the joint body 20 due to an increase in the pressure in the air chamber 44. At the same time, the lock release cylinder 42 integrally pushes the outer cylinder 33 backward via the stopper ring 45. Due to the rearward displacement of the outer cylinder 33, the lock is released and the plug P can be removed as in the first embodiment. in this way,
In the second embodiment, since the operation of releasing the lock does not need to be performed manually, the burden on the operator is reduced.

[Other Embodiments] The present invention is not limited to the embodiment described above with reference to the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition, various changes can be made without departing from the scope of the invention. (1) In the above embodiment, the case where the opening / closing valve mechanism of the pipe joint and the plug is provided has been described.

(2) In the above embodiment, the movable lock piece is a spherical lock ball. However, according to the present invention, the movable lock piece may have a shape other than a spherical shape. (3) In the above embodiment, the movable control piece is a spherical control ball. However, according to the present invention, the movable control piece may have a shape other than a spherical shape. (4) In the above embodiment, the lock ball is engaged with the lock groove by the outer cylinder before the outer cylinder is released from the control ball and vigorously moves forward in the process of rearward displacement of the inner cylinder due to insertion of the plug. Although the state is maintained in the state, according to the present invention, the outer cylinder may be vigorously displaced forward while the lock ball is not maintained in the state of engagement with the lock groove.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a plug is removed in a first embodiment.

FIG. 2 is a cross-sectional view showing a state during connection of a plug.

FIG. 3 is a sectional view showing a state where a plug is connected.

FIG. 4 is a cross-sectional view showing a state where a lock is released when a plug is connected.

FIG. 5 is an exploded perspective view.

FIG. 6 is a cross-sectional view showing a state where a lock is released in a state where a plug is connected in the second embodiment.

FIG. 7 is a sectional view showing a state where a plug is connected in the second embodiment.

FIG. 8 is a cross-sectional view showing a state where a plug is connected in a conventional example.

FIG. 9 is a sectional view showing a state before a plug is connected in a conventional example.

[Explanation of symbols]

 P ... Plug S ... Piping joint 10 ... Lock groove 11 ... Seal surface 20 ... Coupling body 22 ... Control ball (movable control piece) 23 ... Inner cylinder 23A ... Front end face of inner cylinder (restriction part) 29 ... Lock ball (movable lock) 30) Seal member 31 ... Stopper (regulator) 33 ... Outer cylinder 42 ... Lock release cylinder 43 ... Port 44 ... Air chamber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J106 AB01 BA01 BB01 BC04 BC12 BD01 BE12 BE29 CA03 CA14 CA16 CA17 EA03 EB07 EC02 EC07 ED32 EE13 EF05 EF07 EF08 EF15 GA03 GA23

Claims (4)

[Claims] 1. A pipe joint which has a lock groove formed on the outer periphery thereof and is connected to a cylindrical plug whose outer periphery in front of the lock groove is a sealing surface, wherein the joint has a cylindrical shape. A main body; a movable control piece provided in the joint main body so as to be displaceable in a radial direction; and a plug that allows insertion of the plug from the front, and is fitted inside the joint main body so as to be axially displaceable and forward. An inner cylinder urged toward the inner cylinder, a movable lock piece provided in the inner cylinder so as to be displaceable in the radial direction, and mounted rearward of the movable lock piece on the inner periphery of the inner cylinder, with respect to the sealing surface. A sealing member capable of being tightly attached to the joint body, and an outer cylinder which is axially displaceably fitted to the joint main body and urged forward, and in a locked state, the inner cylinder has the movable control piece. Holds at rear position against bias by engagement with The outer cylinder is displaced forward in accordance with the bias to hold the movable control piece in engagement with the inner cylinder, and the movable lock piece is held in engagement with the lock groove by the outer cylinder. In the unlocked state, the outer cylinder is held at the rear position against the bias by engagement with the movable control piece, and the movable control piece is displaced forward by the inner cylinder in accordance with the bias. A pipe joint characterized by being held in an engaged state with the outer cylinder, wherein the movable lock piece is released from being held by the outer cylinder and can be retracted outward from the lock groove. 2. When the plug is inserted into the inner cylinder to a position where the lock groove and the sealing surface correspond to the movable lock piece and the seal member, respectively, the plug is prevented from further inserting operation. The pipe joint according to claim 1, further comprising a restricting portion provided. 3. In a process of rearward displacement of the inner cylinder accompanying insertion of the plug into the inner cylinder, before the outer cylinder is released from forward displacement regulation by the movable control piece,
The pipe joint according to claim 1, wherein the movable lock piece is held in an engagement state with the lock groove by the outer cylinder. 4. A lock release cylinder having a port in the joint body secures an air chamber communicating with the port between an inner periphery of the joint body and an outer periphery of the joint body, and enables movement in the front-rear direction. The unlocked cylinder is displaced rearward by the pressure of the air supplied to the air chamber, and the unlocked cylinder moves the outer cylinder rearward when the unlocked cylinder is displaced rearward. The pipe joint according to any one of claims 1 to 3, wherein the pipe joint is configured to be pushed.