JP3690932B2 - Pipe fitting - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a pipe joint.
[0002]
[Prior art]
Conventionally, as shown in FIG. 5, a lock ring 3 is disposed in the circumferential groove 2 on the inner surface of the receiving port 1, and the insertion port 4 is inserted into the insertion port 4 as a structure having a function of preventing a pipe joint such as a ductile cast iron pipe from coming out. There is known a pipe joint that is provided with a portion 4A and prevents the insertion port 4 from coming out by engaging the insertion port protrusion 4A with the lock ring 3.
[0003]
[Problems to be solved by the invention]
By the way, in order to prevent the lock ring 3 from getting in the way when the insertion port 4 is inserted into the receiving port 1 when the pipe is connected, conventionally, the coupling piece 6 is inserted into the split portion 3A of the lock ring 3 as shown in FIG. The diameter r of the lock ring 3 is increased by expanding the interval of the split 3A, and the lock ring 3 is accommodated in the circumferential groove 2 of the receiving port 1 of FIG. 5, or FIGS. As shown in FIG. 7, the lock ring 3 having a free opening is stored in the circumferential groove 2, and after inserting the insertion slot 4, the lock ring 3 is pressed from the outer periphery with the set bolt 3 </ b> B as shown in FIG. The tube 3C is inserted into the back surface of the lock ring 3 as shown in FIG. 7 (b), and a grout is press-fitted into the tube 3C to expand the outer periphery of the lock ring 3. It is performed to press from.
[0004]
However, prior to the pipe connection work, the coupling piece 6 as shown in FIG. 6 is inserted through a narrow gap between the inner surface of the receiving port 1 and the outer surface of the insertion port 4 and incorporated using a jig (not shown). However, there was a problem that it was very time-consuming and troublesome.
In the case of the structure shown in FIG. 7 (a), a number of set bolts 3B arranged around the pipe must be tightened evenly after pipe joining, and in the case of the structure shown in FIG. A means for injecting grout at a high pressure after the work was required, and there was a problem that the construction was very troublesome and the efficiency was poor.
[0005]
The present invention provides a pipe joint that can store a lock ring without using a coupling piece or the like as described above, and that can be prevented from coming out without the need for fastening work such as a set bolt after the insertion port is inserted. Is made as an issue.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, the pipe joint of the present invention is configured such that the lock ring is housed in the circumferential groove formed on the inner surface of the receiving port, and the insertion port having the insertion port protrusion on the outer periphery on the distal end side has the insertion port. In the pipe joint in which the protrusion is inserted into the receiving port up to a position on the deeper side of the receiving port than the lock ring, and the receiving port and the insertion port are connected, both outer side surfaces of the lock ring are tapered. A notch surface is formed, the notch surface is inclined with respect to the outer surface of the insertion port in a range of 50 ° to 70 °, and a tube is formed on the side surface of the circumferential groove on the receiving opening side from the groove bottom. A rising surface that rises toward the axial center of the groove, and a tapered surface that extends from the rising surface toward the opening of the receiving port and that can come into contact with the cutout surface on the receiving port opening side of the lock ring. On the side of the receiving port When a surface other than the notch surface on the outer side of the receiving opening of the groove hits the taper surface of the circumferential groove, the notch surface on the back side of the receiving end of the lock ring can face the tube from the groove bottom. It is characterized in that a rising surface rising toward the axis is formed .
[0007]
According to the above invention, if the split ring housed in the circumferential groove on the inner surface of the receiving port is inserted and the diameter is expanded at the end surface of the opening, it can be inserted and connected as it is. Due to the contact between the tapered surface formed on the ring and the circumferential groove on the inner surface of the receiving port, the split lock ring is deformed in a reduced diameter, and the engagement with the insertion port protrusion is ensured. Further, at this time, the notch surface in the lock ring is inclined in the range of 50 ° to 70 ° with respect to the outer surface of the insertion port, so that the withdrawal force acts on the pipe joint and the insertion port in the lock ring. When the protrusion is engaged, it is possible to prevent the lock ring from overturning or the radial tightening force of the lock ring from becoming too strong.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described.
FIG. 1 is a cross-sectional view of a pipe joint.
In FIG. 1, a pipe joint 10 is formed with a circumferential groove 2 having a tapered side surface 2 </ b> A on the opening side on the inner surface of the receiving opening 1. A lock ring 3 having a tapered notch surface 3C is accommodated, and an insertion port 4 having a protrusion 4A formed at an end thereof is inserted and connected.
[0009]
In the above description, the insertion port protrusion 4A shows the case where the convex portion forming member 5 is inserted into the circumferential groove 4B formed on the outer surface of the insertion port 4 and attached by welding 5A, 5B, as shown in FIG. Thus, it may be provided integrally on the outer surface of the tube end of the insertion port 4. In the pipe joint, as shown in FIG. 2, the taper angle θ of the taper surface 3C with respect to the outer surface of the insertion port 4 is preferably 60 ° ± 10 °, that is, 70 ° ≧ θ ≧ 50 °.
[0010]
Such a rising angle θ may be caused when the locking force falls on the pipe joint and the lock ring 3 falls when the lock ring 3 is engaged with the insertion projection 4A, or the radial tightening force is too strong. In order to prevent this, it has been confirmed by experiments. That is, when the inclination angle θ is greater than 70 °, when a pulling force is applied to the tube, the radial tightening force of the lock ring 3 is not sufficiently exhibited, and the lock ring falls or the lock ring is deformed by a shearing force. Because there are cases.
[0011]
On the other hand, when the inclination angle θ is reduced, the radial tightening force of the lock ring 3 becomes too large when a strong escape force is applied, which is inappropriate for the strength of the tube. Therefore, it is preferable to make the inclination angle θ larger than 50 °.
Next, a method for connecting pipe joints will be described.
When connecting the pipe joint 10, first, the lock ring 3 is disposed in the circumferential groove 2 of the receiving port 1, and the insertion port 4 is inserted in that state.
[0012]
Since the end face of the insertion slot 4 is usually chamfered, the lock ring 3 receives a diameter-expanding force at this chamfered face, expands the diameter by the split 3A, and passes through the end of the insertion slot 2. Next, the insertion port protrusion 4A is similarly passed, and thereafter the lock ring 3 is restored and contracted so that it is wound around the outer periphery of the insertion port 4 while being accommodated in the circumferential groove 2.
Accordingly, a jig for expanding the diameter of the lock ring 3 is not necessary when the insertion port 4 is inserted and connected to the receiving port.
[0013]
Next, the operation of the pipe joint withdrawal prevention structure will be described.
When the insertion preventing force acts on the pipe and the insertion port 4 tries to come out of the receiving port 1 and the insertion projection 4A comes into contact with the lock ring 3 as shown in FIG. An axial force indicated by an arrow X and a radial contraction force Y are generated in pressure contact with the taper surface 2A, and the lock ring 3 is engaged by the radial contraction force Y so as to tighten the outer surface of the insertion port 4. The engaged state with the protrusion 4A is stabilized.
[0014]
For this reason, the lock ring 3 does not fall down or undergo shear deformation even when a strong force is applied.
In addition to the illustrated pipe joint, the pipe joint withdrawal prevention structure of the present invention can be implemented in exactly the same way even with a pipe joint as shown in FIG.
[0015]
In addition, in the figure of FIG. 4, the member shown with the same code | symbol as the code | symbol shown in FIGS. 1-2 is the same member or a corresponding member.
EXAMPLE For the pipe joint shown in FIG. 1 and having a target nominal diameter of 500 to 1000 mm, the lock ring 3 has a trapezoidal shape as shown in FIG. 2, and the inclined angles of the tapered surfaces 3C and 3C. A θ having 60 ° was prepared.
[0016]
The lock ring 3 is set in the circumferential groove 2 of the receiving port 1, the insertion port 4 A is inserted into the insertion port 4 by welding as shown in FIG. A push ring 8 was attached to complete a test pipe joint.
The test apparatus applied a tensile force to both ends of the pipes connected by pipe joints and observed the presence or absence of abnormalities.
[0017]
As a comparative example, the pipe joint shown in FIG. 5 was used.
As a result, there was no abnormality even when the example was loaded with 0.4 Dtf (D is diameter mm), but in the comparative example, both the deformation of the lock ring and the distortion of the insertion opening were large when loaded with 0.3 Dtf.
Next, a repeated tensile test in which the joint part assembled without the rubber ring 7 is expanded or contracted 20 times or more, and a rapid tensile test in which the joint part assembled with the rubber ring 7 is rapidly loaded with a 300 tf tensile force 10 times. Similarly, when the pipe joint part was repeatedly bent and bent approximately 5 ° up and down, left and right approximately 5 °, and the joint part was subjected to an impact bending test in which bending rigidity (20 tf · m) was impacted 10 times. No abnormality occurred in the ring.
[0018]
【The invention's effect】
As described above, according to the pipe joint of the present invention, it is possible to reliably prevent the pipe joint from coming out without using a coupling jig or a set bolt, and the construction management of the pipe connection work is facilitated. In addition, since the pipe joint escape prevention structure of the present invention can be applied to any pipe joint that prevents the lock ring from coming out, there is an effect such as versatility. Furthermore, the notch surface in the lock ring is inclined in the range of 50 ° to 70 ° with respect to the outer surface of the insertion port, so that the escape force acts on the pipe joint so that the insertion port protrusion is formed on the lock ring. When engaged, it is possible to prevent the lock ring from overturning and the lock ring's radial tightening force from becoming too strong.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a pipe joint according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of the pipe joint of the present invention.
FIG. 3 is a sectional view for explaining the operation of the pipe joint of the present invention.
FIG. 4 is a cross-sectional view of another configuration example of the pipe joint withdrawal prevention structure according to the present invention.
FIG. 5 is a cross-sectional view of a conventional fitting prevention pipe joint.
FIG. 6 is a front view showing a state in which the diameter of the lock ring is expanded using a coupling piece.
FIG. 7 is a cross-sectional view of an essential part showing a conventional escape prevention joint.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Receptacle 2 Circumferential groove | channel 2A Circumferential groove side surface 3 Lock ring 3B Lock ring inner surface 3C Tapered part 4 Insert port 4A Insert port protrusion 5 Insert member protrusion metal member 5A Outer peripheral side 5B Both sides 7 Rubber ring 8 Push ring

Claims (1)

The lock ring is housed in a circumferential groove formed on the inner surface of the receiving port, and the insertion port having the insertion port protrusion on the outer periphery on the distal end side is on the back side of the reception port with respect to the lock ring. In the pipe joint that is inserted into the receiving port to a position and is connected to the receiving port and the insertion port, tapered notch surfaces are formed on both outer side surfaces of the lock ring, and the notch surface is A rising surface that is inclined in a range of 50 ° to 70 ° with respect to the outer surface of the insertion opening, rises from the groove bottom toward the axis of the tube, A tapered surface that is in contact with the cutout surface on the receiving opening side of the lock ring and is formed on the side surface on the back side of the receiving opening of the circumferential groove. Other than the notch on the outer side of the opening side When the surface of the ring contacts the taper surface of the circumferential groove, a rising surface rising from the groove bottom toward the axis of the tube is formed so that the notch surface on the back side of the lock ring can face each other. A pipe joint characterized by that.

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