JP3402171B2 - Captive 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 for preventing segregation of pipes buried underground such as for water supply, sewerage, and gas.

[0002]

2. Description of the Related Art The main body of a pipe forming a pipe line to be buried underground is a ductile cast iron pipe which is excellent in workability during laying.
In this pipe, one pipe end is expanded into the receiving port and the other pipe end is inserted, and a rubber ring is inserted in the gap between them to maintain the watertightness of the pipe line. It plays a major role in pipelines that supply fluids such as sewage and household gas. Since pipes are buried underground, prevention of separation between pipes is an important factor, and water leakage from pipe joints should not cause waste of valuable water resources.

Currently, most of the joints used in ductile cast iron pipes are standardized in K type, A type, T type and the like, and since the joints of these pipe lines are stretchable and flexible. It is a flexible structure that adapts to some degree of earthquake and crustal deformation in soft ground. However, in recent years, the demand for seismic resistant pipes has increased even more since the Great Hanshin Earthquake, and the development of higher level seismic resistant pipe joints has been rushed. The SII type joint was developed and put to practical use in this background.

On the other hand, the so-called slip-on type, which is a non-fastening joining method in which the push ring and the socket flange of the ductile cast iron pipe are not fastened with bolts and nuts, but is simply inserted into the socket and inserted, the so-called slip-on type has a laying workability. Although this is an epoch-making method that can be greatly improved, there is still a growing need for improved seismic resistance even when forming a pipeline using this method, so a structure to prevent separation is proposed. -13
No. 3090, No. 4-133091, No. 4-1
Although each publication of No. 33092 is found, both of them are related to the SII type joint as to the idea itself that the lock ring is fitted, and the separation prevention effect is exerted against the external force of engaging with the insertion opening ring and pulling it out. It consists of almost common points.

As a typical example, a standardized and generalized NS type pipe joint is shown. As shown in FIG. 6, an annular groove 102 is formed in a socket 101 of a ductile cast iron pipe, and a lock ring 103 is cored. An insertion opening 105 to be joined while sandwiching the rubber ring 104 for insertion while being joined is provided with an insertion opening projection 106 at the tip and is inserted into the receiving opening, and the insertion opening facing the peripheral surface near the receiving opening tip. A rubber ring 107 is fitted between the outer peripheral surface and the outer peripheral surface to keep the joint water-tight and secure a water-stop surface pressure for preventing water leakage.
Moreover, when the water pressure from the inside of the pipe rises, the surface pressure of the rubber ring also rises and the self-sealing action is provided. When an external force is applied in the direction of pulling out the pipe joint portion, the dual positional relationship between the pipes changes and movement in the pulling direction starts. However, this movement is stopped when the lock ring 103 on the receiving side collides with the insertion protrusion 106, and further withdrawal action does not proceed, so that separation between the pipes is prevented and the pipe line is divided, and The main structure is to avoid the outflow of water.

[0006] On the other hand, the pipe line for tap water buried in the ground is not composed of only a straight pipe as is well known, and it is sure to bend a road by combining a straight pipe and a deformed pipe. It is a general principle to form a compliant line. Obviously, the variability of the pipeline that follows this swing is an indispensable requirement for sudden pitching and rolling such as an earthquake. But,
It goes without saying that the prevention of disengagement and the prevention of excessive intrusion are major prerequisites for the pipe joint portion between the deformed pipe and the straight pipe, but the straight pipe that simply allows a large amount of flexibility and strengthens the earthquake resistance. It is necessary to pay attention to the fact that if the idea is applied as it is and the bending and expansion and contraction of the pipe joint are allowed freely, there is a converse effect of losing the function of the entire pipeline.

As a joint portion of a pipe line including a deformed pipe, a separation preventing pipe joint in which the deformed pipe portions are firmly integrated is usually used. FIG. 7 shows a conventional pipe fitting for a deformed pipe and a straight pipe, which are compliant with the slip-on type, as shown in FIG.
This is an example of joining the insertion port 202 of the straight pipe to 01.
Lock ring 203, insertion protrusion 204, rubber ring 205
In addition to the above, the bending prevention ring 206 is fitted into the annular groove on the inner peripheral surface near the tip of the receiving port and is engaged with the set bolt 207 to form the NS type joint in which the proof strength in the bending direction is strengthened.

As another example, conversely, FIG.
7 shows a case of an NS type pipe joint that joins the insertion port 302 of the deformed pipe. Instead of the bending prevention ring in FIG. 7, a liner 303 is fitted from the tip of the insertion port to the step surface at the deepest part of the receiving port,
The bending prevention protrusion 304 is inserted and disposed on the outer peripheral surface of the opening to enhance bending rigidity. Prior art No. JitsuHiraku flat 7-38870 than those disclosed nearly this configuration, the liner to regulate this when inserting opening protrusion moves port inserted from the position engaged with the lock ring further receptacle rear side The purpose of the present invention is to fix the ring for preventing the bending of the insertion opening and the receiving opening by filling the gap between the inner peripheral surface of the opening of the receiving opening and the outer peripheral surface of the insertion opening facing the opening.

[0009]

In the NS type and other prior art joints for straight pipes, the seismic structure is emphasized to allow the receiving port and the insertion port to move within the mutual insertion range, and The biggest point is to have a stretching action that changes the positional relationship and absorbs external force. On the other hand, however, this expansion and contraction caused damage, and in order to conduct a hydraulic test of the joints that were joined at the site where the pipeline was laid, the pipeline was not backfilled and the relative position of the pipeline was fixed, and When the test water pressure is applied, there is a possibility that the relative positional relationship of the joint part may change and expansion and contraction may occur, and the pipe line may meander or the axis line may change.

On the other hand, in a pipeline including a deformed pipe, there is a unique problem of setting protection against non-uniform force associated with bending of the pipeline. Concrete block protection is usually applied to counter this external force, but when the concrete block becomes too large or it is impossible to place it in response to complicated bends in the pipeline. Generally uses a joint provided with a separation prevention mechanism, and rigidly connects the joint for preventing movement of the deformed pipe portion. At this time, it is a necessary condition for the joint used for the deformed pipe portion to have a bending rigidity sufficient to withstand the bending moment acting on the rigidly connected joint. If the limit bending moment (flexural rigidity) of the joint is low, the distance that must be integrated (rigid) increases, so many pipe joints with a structure that constrains the flexibility and expansion and contraction must be inserted. After all, although the bending rigidity is high as shown in Fig.7 and Fig.8, it has to be oriented in the direction opposite to the social needs to further strengthen the seismic resistance so that it can easily adapt to the fluctuation of the ground. The problem of not remaining remains.

In order to solve the above problems, the present invention provides a so-called chain structure pipeline that can adapt to a large ground movement such as an earthquake in a straight pipe section, and is provided with a restraining force that allows a hydraulic test before backfilling. For a large pull-out force that can cope with normal pipeline pressure and exceeds the restraining force such as an earthquake during use, a disconnection prevention type pipe joint that finally functions to maintain the passage of water through the separation prevention function works. For the purpose of provision.

[0012]

DISCLOSURE OF THE INVENTION A separation prevention type pipe joint according to the present invention is fitted into a receiving opening 1 and an inserting opening 2, a rubber ring 3 interposed between them, and an annular groove 11 formed in the receiving opening 1. In a disconnection preventing type pipe joint comprising a lock ring (4) for preventing separation and an insertion port projection (21) which is provided around the distal end side of the insertion port (2) and engages with the lock ring (4), an insertion including an insertion port protrusion (21). An upright surface 51 which is inserted into the outer peripheral surface of the mouth 2 and contacts an upright side surface 22 corresponding to the lock ring side of the mouth projection 21, and the upright side surface 2
The inclined surfaces 52 pushed up by the movement of the distal end of 2 are alternately repeated, and each of them is provided with a radially expanded portion 50 which is radially arranged and forms a step over the entire inner circumference. Spacer 5 composed of a biased flexible annular body
Is characterized in that they are fitted together.

To show this structure more concretely, the area where the upright surface 51 of the spacer 5 contacts the upright side surface 22 of the insertion projection 21 is normally the minimum dimension that can oppose the withdrawal force acting on the pipe joint when the water pressure is P1. And

[Equation 2] It is set according to the conditions of and when the unsteady external pressure P2

[Equation 3] Conditions is in the corner of the enlarged diameter portion 50 pushes back the urging force external force of equipped with flexible engaging deviate strength upright side face 22 and an upright surface 5 1 of inserted ports projections deformed buckling The most desirable form is a split annular body consisting of material and dimensions, and the most common material of the spacer 5 is a plastic material that is insoluble in water and is healthy and harmless to water, such as polyethylene, polypropylene and nylon. Target,
The material is not necessarily limited, and it does not matter whether the material is a metal material or a composite material as long as the condition of the above-described mathematical expression 2 is satisfied.

With respect to the positional relationship of joining, when the spacer 5 is fitted to the outer peripheral surface of the insertion opening, the upright surface 51 of the expanded diameter portion 50 is entirely separated from the upright side surface 22 of the insertion opening projection 21 with a gap S therebetween. The ridge 1 that is opposed to and is attached to the outer peripheral surface 25 of the insertion opening, the projection 21 of the insertion opening, and the tip 23 of the insertion opening, and one end 54 of the spacer 5 forms the receiving annular groove 11.
After joining the insertion opening 2 into the receiving opening 1 until it comes into contact with the inner side surface 12 of 4, when the normal water pressure P1 is applied, the spacer pushed up as the insertion opening projection 21 moves until S = 0. 5 has expanded in diameter and has an upright surface 51 and an upright side surface 22.
It is optimal that the contact is made only at the height h locked by and the positional relationship in which the receiving opening and the insertion opening are immovable is maintained under the normal water pressure P1. Also, if we consider mainly the test before backfilling when laying a pipeline, which is an important issue, the diameter-expanded portion 50A continues to have the same diameter up to the other end 55A on the deep side of the inlet while the diameter-expanded portion 50A is expanded with a step. Spacer 5 forming the inner peripheral surface
You can take the form of A.

[0015]

1 (A), 1 (B) and 1 (C) are longitudinal sectional front views of the main part showing the main operation of the embodiment of the present invention. FIG. 1A shows a state in which the pipes have been joined and the pipe has been formed. The basic structure is that the insertion port 2 is inserted into the receiving port 1 and the inner peripheral surface 15 at the tip of the receiving port is opposed. Outer peripheral surface 25
A rubber ring 3 having a self-sealing effect is interposed between the pipe and the pipe to seal the pipe with water, and is urged toward the inner diameter side (reduced diameter side) in 10% through the lock ring centering rubber 41. Lock ring 4
Is fitted into the receiving annular groove 11 and inserted to face the outer peripheral surface 25 of the opening. The insertion opening projection 21 is composed of an upright side surface 22 on the lock ring side and an inclined surface 24 that gently extends to the insertion opening tip 23,
The spacer 5 made of a one-piece annular body is externally fitted over the outer peripheral surface of the insertion opening including the insertion projection 21 and the distal end 23 of the insertion opening. It maintains the positional relationship attached to the outer peripheral surface of the insertion slot.

A major structural feature of the present invention is the shape in which the spacer 5 engages with the insertion protrusion 21. That is, as shown in FIGS. 2 (A) to 2 (E), the spacer 5 is in a split ring state including a cut portion 53, and the starting end of the enlarged diameter portion 50 is the upright side surface 22 of the insertion protrusion 21. An upright surface 51 (filled in black) that faces the entire surface and finally comes into contact with and locks in a limited range, and an inclined surface 5 that is pushed up by the tip of the upright side surface 22 and expands the entire spacer 5 in the outer peripheral direction.
2 (white) is alternately repeated to form a step over the entire circumference. 2A is a sectional view taken along the line P-P of FIG. 2A and FIG. 2C is an enlarged view of an essential part, and includes an upright surface 51 formed of upright steps, while Q in FIG. The -Q cross section corresponds to the same figure (D) and the enlarged view (E) of the main part, and has an inclined surface 52 that is pushed up by the tip of the upright side surface as it moves.

FIG. 1 (B) shows a state in which water is passed through a pipe to conduct a leak test by steady water pressure, and then the water is refilled and the water pressure actually works in the direction of pulling out the pipe joint. When water pressure P1 is applied from the inside of the pipe, the insertion opening starts to move in the pulling-out direction, and the inclined surface 52 is pushed up by the forward end of the upright side surface 22, and the entire spacer 5 is expanded toward the inner peripheral surface of the receiving opening. 3 (A) and 3 (B) are enlarged views showing the engagement relationship between the spacer and the insertion opening projection at this time, and the inclined surface 52 in contact with the tip of the insertion opening projection 21 in the expanded diameter portion is shown. The entire spacer 5 is expanded by being pushed up along with the movement that receives an external force, but in the end, under normal water pressure, even when the movement is finished until the gap S becomes 0, the range of surface contact of height h only Remains and the upright side surface 22 and the upright surface 51 (filled in black) are calculated so that the shape and strength of the spacer are set. Therefore, the diameter is further expanded and the locking does not come off. Under normal water pressure P1 , the relative positional relationship between the insertion opening 2 and the receiving opening 1 is maintained unchanged.

FIG. 1 (C) shows a stage where a large unsteady pulling force acts due to an earthquake, etc., and P2 set by the mathematical formula 3 acts to concentrate on the engaging surface and exceeds the set shear strength of the spacer. The corners of the expanded diameter portion 50 are buckled and deformed, and finally the upright side surface 22 and the upright surface 51 are disengaged from each other, and the insertion opening moves over the stepped surface of the expanded diameter portion and moves in the pull-out direction. In other words, the position changes to absorb an excessive external force, and the flexible seismic resistance is added so that the pipe is expanded and contracted to avoid destruction. The limit of the movement is the contact between the insertion protrusion 21 and the lock ring 4, and the side surfaces of both members collide with each other to prevent further movement, so that the joint between the pipes is not disengaged. It is the same as that of the conventional technique.

4 (A) to 4 (D) show the procedure of construction for carrying out the present invention. In FIG. 4 (A), the spacer 5 is deposited in the receiving port 1 and in FIG. 4 (B). The lock ring 4 and the centering rubber 41 are fitted in the annular groove 11 of the receiving port 1, and the rubber ring 3 is mounted in the recess provided in the inner peripheral surface near the tip. In FIG. 2C, the insertion slot 2 is inserted into the receiving slot 1. At this time, since the spacer 5 is a flexible one-piece annular body having a dividing portion, it temporarily stops when the insertion projection 21 is crossed over. The urging force is pushed back to expand the diameter. Figure (D)
At, the insertion opening 2 is inserted to a predetermined position to complete the joining. It is desirable that one end 54 of the spacer 5 is in contact with the inner side surface 12 of the protrusion 14 forming the receiving annular groove 11 and the other end 55 faces the step 13 at the deepest part of the receiving opening with a margin.

FIG. 5 is a vertical cross-sectional front view of a main portion showing another embodiment of the present invention. The expanded diameter portion 50A of the spacer 5A has the same starting end as in FIG. 55A
It is a structure that mainly considers the on-site water pressure test after laying the pipeline in the straight pipe part.

[0021]

EFFECTS OF THE INVENTION The present invention is based on the NS type joint which has been standardized as a typical example of the conventional separation prevention type pipe joint, but does not require any additional process such as processing of the receiving port and the insertion port. In addition, no special jigs, tools, or complicated procedures are added at the time of joining, and by simply installing a spacer it also has an expansion and contraction function and improves the earthquake resistance all at once, so the economic burden is minimal. It has a great effect that it can be applied as it is without any trouble in implementation.

Since the application of the present invention exerts an action of sufficiently withstanding the pulling force to the pipe joint due to normal water pressure and restraining it in the immovable joint position, it is a difficult problem common to the quake-resistant pipe joints of the prior art constructed to be expandable and contractible. In other words, the serious bottleneck that can not be done before backfilling the water pressure test after laying is solved, and the irreplaceable advantage of convenience of workability and quick repair after leak detection and improvement of quality reliability accompanying it Is obtained.

When an excessive pulling-out force such as an earthquake is applied, it is an important requirement for maintaining the elasticity of the joint that the locking which normally resists water pressure and disengages is released. The basic configuration is based on the principle that the relative position change due to the yielding (buckling) of the spacer is allowed, and no shearing or breaking of the member is involved, so that sheared debris mixes into the pipeline. In terms of supply, there is no worrying material to avoid, which is an effect that greatly surpasses the conventional technology.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of essential parts at the time of joining (A), at the time of normal water pressure (B), and at the time of excessive external force (C) according to an embodiment of the present invention.

FIG. 2 is a side view (A) of the spacer and P- in FIG.
It is P sectional view (B) and its principal part enlarged view (C), and QQ sectional view (D) and its principal part enlarged view (E).

FIG. 3 is an enlarged view (A) and a side view (B) of only a main part in FIG. 1 (B).

4A to 4D are partially longitudinal front views showing the construction procedure of the embodiment of the present invention.

FIG. 5 is a partially longitudinal front view showing another embodiment of the present invention.

FIG. 6 is a partially longitudinal front view showing a prior art of a separation prevention type pipe joint (straight pipes).

[Fig. 7] N of the type for preventing the detachment of the irregular pipe receptacle and the straight pipe insertion port
It is a partial longitudinal front view of an S-shaped joint.

[Fig. 8] N for prevention of separation between straight pipe receiving port and irregular pipe insertion port
It is a partial longitudinal front view of an S-shaped joint.

[Explanation of symbols]

1 mouthpiece 2 outlet 3 rubber rings 4 lock ring 5 spacers 11 Annular groove 12 Inner surface 13 steps 14 Ridges 21 Insert protrusion 22 Upright side (lock ring side) 23 tip 24 slope 41 Rubber for centering 50 Expanded part 51 Upright 52 Inclined surface 53 divisions

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-332061 (JP, A) Actual Kaihei 7-38870 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16L 21/00-21/08

Claims (4)

(57) [Claims] 1. A receiving opening (1) and an insertion opening (2), a rubber ring (3) interposed therebetween, and an annular groove (1) engraved in the receiving opening (1).
A separation prevention type tube comprising a lock ring (4) fitted to 1) for preventing separation and an insertion port projection (21) which is provided around the distal end side of the insertion port (2) and engages with the lock ring (4). In the joint, an upright surface (51) that comes into contact with an upright side surface (22) corresponding to the lock ring side of the insertion port protrusion (21) on the outer peripheral surface of the insertion port (2) including the insertion port protrusion (21), and the upright surface. An inclined surface (52) which is pushed up with the movement of the tip of the side surface (22) is alternately repeated, and each of which is provided radially with a diameter expansion portion (50) forming a step over the entire inner circumference,
A separation prevention type pipe joint characterized in that a spacer (5) made of a flexible annular body which is urged in a diameter-reducing direction is fitted as a whole. 2. The area of contact between the upright surface (51) of the spacer (5) and the upright side surface (22) of the insertion opening projection (21) in claim 1 is such that it normally opposes the withdrawal force acting on the pipe joint when the water pressure is P1. It is the smallest size that can be And sets the conditions, non-stationary external pressure P2 sometimes enlarged diameter portion pushes back the urging force external force (50) upright side surfaces of the corner is inserted deformed buckling mouth projections (22) and an upright plane ( 5 1 ) A disconnection prevention type pipe joint, characterized in that it is a split annular body made of a material and dimensions having strength and flexibility for disengagement. 3. The disconnection preventing type pipe joint according to claim 1, wherein the spacer (5) is made of polyethylene, polypropylene, nylon or other plastic material which is insoluble in water and harmless to health. 4. The upright surface (51) of the expanded diameter portion (50) according to claim 1, when the spacer (5) is fitted to the outer peripheral surface of the insertion opening, the upright side surface (22) of the insertion opening protrusion (21). And the insertion opening outer peripheral surface (25), the insertion opening projection (21), and the insertion opening tip (2).
3) and is impregnated, one end of the spacer (5) (54)
After joining the insertion opening (2) into the receiving opening (1) until the contact with the inner surface (12) of the protrusion (14) forming the receiving annular groove (11), normal water pressure P1 was applied. When S = 0
The spacer (5) pushed up expands as the insertion protrusion (21) moves until it becomes so that it abuts only at the height h at which the upright surface (51) and the upright side surface (22) engage. A disconnection prevention type pipe joint characterized in that the receiving port and the inserting port maintain a fixed positional relationship under normal water pressure P1.