JPH1194157A - Detachment preventing expansion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably maintain excellent liquid tightness even in the case of a joint part receiving external force in the bending direction and in the eccentric direction by forming a lock ring storage part at the socket inner surface of a synthetic resin pipe, while forming a fastening part to be fastened to a lock ring, at the outer surface of a spigot, and forming the fastening part, formed at the spigot outer surface, of an annular groove. SOLUTION: In a spigot 1 formed of polyolefine resin such as high-density polyethylene by an injection molding method or the like, an annular groove 3 for fastening a lock ring 8 so as to prevent detachment is formed at the outer periphery of a tip part. An annular groove 5 is provided at the inner peripheral surface on the opening end part side of a socket 2. A sealing packing 6 is mounted in the annular groove 5, and an annular lock ring storage part 7 is formed on the inner part so as to accommodate the diameter expandable/ contractible lock ring 8 of single split structure therein. Tapered faces T are respectively formed at the opposed faces of the lock ring storage part 7 and lock ring 8, and when force in the socket opening side direction is applied to the lock ring 8, the lock ring 8 is contracted in diameter to ensure liquid tightness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a synthetic resin pipe joint having both flexibility and prevention of detachment.

[0002]

2. Description of the Related Art A joint having a structure as shown in a sectional view of a main part in FIGS. 3A and 3B is known as a joint having both elasticity and detachment prevention. That is, FIG.
In (B), reference numeral 1 denotes an insertion opening, 2 denotes a reception opening, and an annular projection S is formed on the outer periphery of the distal end portion of the insertion opening 1, and a chamfered tapered surface 4 is provided on the outermost end of the insertion opening. I have. On the other hand, an annular groove 5 for mounting a sealing gasket is provided on the inner peripheral surface on the opening side of the receiving port 2, and a sealing gasket 6 is mounted on the annular groove 5. Is formed, and a lock ring 8 that can be easily tightened is attached to at least one of the hardly deformable materials such as metal,
Further, a cavity portion 10 having an appropriate length is formed on the back side thereof to allow the distal end portion of the insertion opening 1 to move in the tube axis direction (left-right direction in the drawing).

On the opening side of the lock ring housing 7 and the lock ring 8, the tapered surface T having the same gradient is formed.
Are respectively provided, the insertion opening 1 moves to the left (outward direction), and the left vertical surface (locking surface) of the annular projection S comes into contact with the lock ring 8, and further attempts to move in the outward direction. When a force is applied to the ring 8 in the opening direction,
The lock ring 8 is configured to be able to reduce the diameter while slightly sliding along the tapered surface T.

Accordingly, with the seal packing 6 mounted in the annular groove 5 of the receiving port 2 and the lock ring 8 mounted in the lock ring accommodating portion 7, respectively, the tapered surface 4 on the outer periphery of the front end of the insertion port 1 is used to insert the seal. In a state in which the annular projection S at the tip of the port 1 is pushed into the lock ring 8 [FIG. 3 (A)], the insertion port 1 and the receiving port 2 receive a sealing action by the sealing packing 6 and are connected in a liquid-tight manner. The insertion opening 1 is allowed to be inserted in the depth direction of the receiving opening 2 by the axial length of the cavity 10. On the other hand, the slot 1 is shown in FIG.
From the state of (A), it is possible to cope with the extension of the entire pipeline by moving in the direction of the arrow, but when the annular projection S at the tip comes into contact with the lock ring 8, the movement in the removal direction is prevented [FIG. 3 (A)], where separation is prevented.

[0005] Incidentally, the above-mentioned joint structure is conventionally made of a metal material such as cast iron, and by having the above-described receiving / inserting joint structure, it is possible to have expandability and contraction in the tube axis direction. The detachment of the joint part could be prevented. However, recently, problems such as weight reduction and cost reduction of the joint material and rusting have been pointed out, and there has been a tendency to produce such a joint with a hard synthetic resin material such as high-density polyethylene. ing.

[0006]

Even if the joint is made of a synthetic resin as described above, the joint shown in FIG. 1 can effectively exhibit the elasticity of the joint and the prevention of disengagement. However, it has been confirmed that such a joint made of a synthetic resin pipe causes a new problem due to a lack of flexibility of the material as compared with a metal material.

That is, when an external force in a bending direction or an eccentric direction is applied to such a synthetic resin pipe joint portion due to ground deformation due to land subsidence or an earthquake, liquid leakage occurs at the joint portion. The reason is considered as follows.

That is, in the above-described joint, when an external force in a bending direction or an eccentric direction is applied to a relatively thin-walled insertion port, the insertion port 1 bends as shown in FIG. The gap between the ports 2 is partially widened, and the sealing packing 6 becomes poorly adhered at the portion, loses liquid tightness, and causes liquid leakage.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems encountered when a synthetic resin joint is put into practical use. It is an object of the present invention to provide a synthetic resin expansion / contraction preventing joint capable of stably maintaining excellent liquid tightness even when a portion receives an external force in a bending direction or an eccentric direction.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems by providing a joint for preventing expansion / removal of a pipe having a sealable connection structure in which a mouth and a mouth of a synthetic resin pipe can expand and contract. A detachment prevention joint having a lock ring receiving portion on the inner surface and a hook portion on the outer surface of the insertion hole which is engaged with the lock ring, wherein the most innermost surface of the receiving port is brought close to the outer surface of the insertion port. It has a gist in that it is formed with an inside diameter and the engaging portion on the outer surface of the insertion opening is formed by an annular groove.

In practicing the present invention, the inner surface of the insertion port corresponding to the annular groove for engaging the lock ring in the insertion port is swelled or has a higher rigidity than the synthetic resin material constituting the insertion port. If the annular groove is reinforced from the inner surface side by the hardly deformable material, when the lock ring is prevented from being detached, the annular groove portion is prevented from being damaged due to a force applied in a diameter reducing direction or a removing direction of the lock ring. It is preferable because the function of preventing separation can be more reliably exerted.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, there is provided a synthetic resin joint having the above-described structure for preventing expansion and disengagement, wherein the innermost end surface of the receptacle has an inner diameter close to the outer surface of the insertion opening. At the same time, an annular groove is formed as a locking portion for locking the lock ring on the outer surface on the insertion side, and the lock ring and the locking surface on the inner surface of the receiving port are configured to prevent detachment. Even when an external force is applied to the insertion portion as described in detail below, the insertion portion is gripped by the most innermost surface of the receiving port,
Enlargement of the gap as shown in FIG. 4 between the receiving port and the insertion port can be prevented, and as a result, a decrease in liquid tightness can be eliminated.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings showing one embodiment. However, the present invention is not limited to the following embodiments, but conforms to the spirit of the preceding and following embodiments. It is, of course, possible to implement the present invention with appropriate modifications within the scope of the invention, and all of them are included in the technical scope of the present invention.

FIG. 1 is an explanatory cross-sectional view illustrating an example of a joint for preventing expansion and disengagement according to the present invention. In FIG. 1, reference numeral 1 denotes an insertion opening, 2 denotes a receiving opening, and these are made of a polyolefin-based resin such as high-density polyethylene. Usually, it is formed by an injection molding method or an insert molding method.

An annular groove 3 for locking the lock ring 8 for preventing the detachment by locking the lock ring 8 is formed on the outer periphery of the front end portion of the insertion opening 1, and an inner surface corresponding to the annular groove 3 is formed. Is expanded to form a thick-walled portion 3 ′, and has a strength to withstand a tightening force from the outer peripheral side received when the lock ring 8 is hooked in the annular groove 3 and a force applied in a pull-out direction. On the other hand, an annular groove 5 is provided on the inner peripheral surface on the opening end side of the receiving port 2, a seal packing 6 is mounted on the annular groove 5, and an annular lock ring housing 7 is formed on the inner side thereof, A lock ring 8 which is elastically expandable and contractable in a split structure made of a hardly deformable material such as a metal material is accommodated therein. Further, a cavity 10 having an appropriate length is formed on the back side thereof to allow the distal end of the insertion port 1 to move in the tube axis direction. In the figure, reference numeral 11 denotes a reinforcing rib provided at a plurality of locations (usually about 4 to 8 locations) on the inner peripheral surface, and 12 denotes a stopper that regulates the insertion end of the insertion opening 1.

The lock ring housing 7 and the lock ring 8 are provided with tapered surfaces T on the opening side of the receiving port 2 respectively. When a force is applied to the lock ring 8 in the direction of the receiving port opening, the lock ring 8 is locked. The ring 8 is configured to be slidable along the tapered surface T so as to be reduced in diameter, and a wall surface on the opening side of the lock ring accommodating portion 7 is engaged with the lock ring 8 to prevent the lock ring 8 from being pulled out. Surface 7a is constituted.

The wall of the annular groove 3 for locking the lock ring, which is provided on the outer peripheral side of the distal end portion of the insertion port 1, is formed as a lock ring locking wall 3a which rises substantially at a right angle. The ring 8 is configured so as to abut against the hooking wall 3a to be hooked, while the wall on the back side of the insertion port 1 is an inclined surface 3b having a small inclination angle. When the lock ring 8 is inserted, the lock ring 8 expands in diameter and moves over the inclined surface 3b so that the lock ring 8 can be easily moved in the depth direction of the insertion opening 1.

Therefore, the opening 1 can be moved in the axial direction between the dashed-dotted positions B and C in FIG. 1 in accordance with the axial length of the cavity portion 10 so that the opening 1 can be expanded and contracted. When the lock ring 8 is engaged with the annular groove 3 and comes into contact with the hooking surface 7a, the insertion opening 1 cannot be moved further leftward and is prevented from being detached.

The innermost end surface of the receptacle 2 is adjusted to have an inner diameter substantially equal to the outer diameter of the insertion port 1 so as to be close to the outer peripheral surface of the insertion port 1. According to the present invention, since the lock ring hooking portion provided in the insertion port 1 is formed by the annular groove 3 so as not to protrude from the outer peripheral surface of the insertion port 1, the lock ring engaging portion is inserted from the front end opening side of the receiving port 2. Mouth 1
Can be inserted into the inside without any trouble.

Further, since the inner surface of the distal end portion of the receiving port 2 is dimensioned so as to have an inner diameter close to the outer surface of the insertion port 1 as described above, for example, as shown in FIG. Even when an external force in the bending direction or the eccentric direction is applied, the insertion port 1 is gripped from the outer peripheral side with almost no gap on the innermost surface of the receiving port 2, and the insertion port 1 is eccentric or is eccentric as shown in FIG. Even when an external force in the deformation direction is received, the gap with the receiving port 2 does not expand. As a result, the pressure contact state of the seal packing 6 does not become uneven in the circumferential direction and the pressure contact does not partially become insufficient, and it is possible to stably maintain high liquid tightness.

In this case, as shown in the figure, if a thick portion 3 ′ is provided by expanding the inner surface of the insertion opening of the annular groove 3 constituting the lock ring hooking portion, the tightening force by the lock ring 8 and the direction of disengagement are provided. This is preferable because the annular groove 3 is not broken by the force applied to the above, and the effect of preventing separation is not lost. However, in the present invention, the thick portion 3 ′ is not always essential, and the point is that the annular groove 3 is employed for locking the lock ring, and the innermost surface of the receiving port 2 is formed as described above. By adjusting the dimensions so that the inner diameter is close to the outer surface, even when an external force in the bending direction or eccentric direction is applied to the joint, the insertion port 1 is gripped from the outer peripheral side by the inner surface at the foremost portion of the receiving port 2 without any gap. As long as the opening 1 is configured so that the gap with the receiving opening 2 does not widen even when the insertion opening 1 receives an eccentricity or an external force in the deformation direction, it is all included in the technical scope of the present invention.

Further, in the example of FIG. 1, as a preferred example, a reinforcing ring 13 is mounted on the inner surface side of the foremost end of the insertion port, and the insertion port 1 is forcibly pushed into the sealing packing 6 or the lock ring 8 as described above. Insert 1 when inserted into socket 2 at
In order to prevent breakage of the distal end portion, a reinforcement sleeve 14 is disposed on the inner side of the inner side of the position where the seal packing 6 is in contact with the back side, and reinforcement by the tightening force by the seal packing 6 is performed. I have. These reinforcing rings 13
As a constituent material of the reinforcing sleeve 14, a material harder than the synthetic resin material forming the insertion opening 1, for example, a metal such as stainless steel or gunmetal, a hard vinyl chloride resin, or a polyphenylene resin may be used.

In the example shown in FIG. 1, the reinforcing ring 13 and the reinforcing sleeve 14 are formed as separate bodies, but they may be formed integrally. These may be mounted in a molding die in advance when forming the insertion opening 1 and integrated by insert molding, or they may be mounted later on the insertion opening formed in advance. In case of retrofitting, it should be open ring-shaped or short tubular with slits in the axial direction for easy mounting, and inserted into the inner surface of the insertion port 1 with its diameter reduced to make it elastic. It is also effective to adhere the inner surface of the insertion hole with the above. In this case, it is preferable that the reinforcing ring 13 and the sleeve 14 are bonded and fixed to the inner surface of the insertion opening 1 by using an appropriate adhesive, because the reinforcing effect thereof can be further enhanced. The reinforcing sleeve 14 is
Since the purpose is to strengthen the tightening force of the sealing gasket 6, it is not necessary to attach the sealing gasket 6 to the entire inner surface thereof. Can be fulfilled.

FIG. 1 shows an example in which the corresponding portion of the annular groove 3 for locking the lock ring in the insertion opening is bulged inward to form a thick portion 3 ′ to reinforce it. For example, as shown in FIGS. 2A and 2B (a cross-sectional view of a main part showing another example of the insertion port 1), the reinforcing ring 13 reaches a position on the inner surface side of the insertion port corresponding to the annular groove 3 for locking the lock ring.
[FIG. 2 (A)], or the reinforcing sleeve 14 is extended to the inner surface side of the thick portion 3 '[FIG. 1 (B)]. Also, it is recommended as a preferable embodiment that the entire inner surface of the end side of the insertion opening 1 is strengthened.

The position and shape of the annular groove 5 and the lock ring accommodating portion 7 provided in the receiving port 2 for engaging the sealing gasket can be arbitrarily changed as necessary. Also, it can be arbitrarily changed according to the required allowable extension length. Note that the lock ring 8 is formed of a single-piece structure ring made of hard-to-deform material such as metal, and has an outer periphery corresponding to a tapered surface formed in the lock long housing portion 7 as shown in the figure. It is desirable to form a tapered surface on the opening side of the receiving port so that the diameter can be smoothly expanded and reduced along the tapered surface without applying a local force to the main body of the receiving port 2.

[0026]

As described above, the present invention is constructed as described above, and exhibits both excellent elasticity and anti-separation properties, and has a high degree of liquid tightness even when subjected to external force due to land subsidence or earthquake. Can be provided, and can be used very effectively as, for example, a pipe joint for water supply.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a typical embodiment of a joint for preventing expansion and disengagement according to the present invention.

FIG. 2 is an explanatory cross-sectional view of a main part illustrating another structure of the insertion slot used in the present invention.

FIG. 3 is an explanatory sectional view of a main part of a conventional joint for preventing expansion and disengagement.

FIG. 4 is an explanatory sectional view of a main part showing a state in which the detachment prevention joint shown in FIG. 3 has lost liquid tightness due to an external force.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insertion opening 2 Reception port 3 Lock ring catching annular groove 3 'Thick part 4 Tapered surface 5 Annular groove 6 Sealing 7 Lock long accommodation part 8 Lock ring 11 Reinforcement rib 12 Stopper 13 Reinforcement ring 14 Reinforcement sleeve

Claims (1)

[Claims] 1. A seal connection structure in which a receiving port and an insertion port of a synthetic resin pipe can be contracted, a locking ring receiving portion is provided on an inner surface of the receiving port, and a locking ring is provided on an outer surface of the insertion port. A detachment prevention joint having a stop portion, wherein the most distal inner surface of the receptacle is formed with an inner diameter close to the outer surface of the insertion port, and the engaging portion of the insertion port outer surface is formed by an annular groove. Characteristic joint that prevents expansion and disengagement.