JP2015190608A - Withdrawal preventing ring for plastic pipe and pipe joint for plastic pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a withdrawal preventing ring for a plastic pipe and a pipe joint for a plastic pipe in which the pipe can be prevented from being withdrawn in a less-expensive manner and easy way while preventing excessive deformation or damage of the pipe without using any in-core.SOLUTION: This invention comprises: a C-shaped ring-like ring main body 20 in which a plastic pipe 2 is inserted from the first opening 21; a plurality of teeth T1 to T6 arranged along a circumferential direction at an inner circumferential surface 20a of the ring main body 20; a pair of flanges arranged to face against both ends of the ring main body 20; and fastening means for fastening a pair of flanges. The first tooth T1 adjacent to the first opening 21 in a plurality of teeth is lower than the other remaining teeth T2 to T6. At least one of other pitches P2 to P5 except the first tooth pitch P1 between the first tooth T1 and the second tooth T2 adjacent to the first tooth T1 is larger than the first tooth pitch P1.

Description

  The present invention relates to a plastic pipe detachment prevention ring and a plastic pipe joint. More specifically, a C-shaped ring main body into which a plastic tube is inserted from the first opening, a plurality of teeth provided along the circumferential direction on the inner peripheral surface of the ring main body, and both ends of the ring main body A pair of flanges provided opposite to each other and a fastening means for fastening the pair of flanges, wherein the plurality of teeth are bitten into the plastic pipe by reducing the diameter of the ring body by the fastening means. The present invention relates to a detachment prevention ring and a plastic pipe joint.

  2. Description of the Related Art Conventionally, as a plastic tube detachment preventing ring as described above, for example, the one described in Patent Document 1 is known. As shown in FIG. 14, the ring is provided with a plurality of teeth t1 to t8 at the same pitch b (tooth pitch P1 ′ to P7 ′) on the inner peripheral surface of the ring body 20 ′, and the tooth height h is Are the same. By reducing the diameter of the ring body 20 ′ by 0.5 to 2.0% with respect to the outer diameter of the plastic tube 2, the teeth t 1 to 8 are bitten into the tube 2 to prevent the tube 2 from being detached.

  In the case where the tube 2 is, for example, a polyethylene tube, a metal in-core is fitted and fitted in order to prevent excessive deformation of the tube due to the reduced diameter of the ring body. Therefore, the cost is high and the work is complicated. 14 is fastened to a polyethylene pipe not fitted with an in-core, and an internal pressure tensile test (tube temperature, normal pressure, 0.5 MPa, number of teeth, tooth height 2.8 mm, tooth angle 30 °) is performed. went. In the result shown in FIG. 15A, the pipe started to slip when the pipe strain was 4.5%, and air leakage occurred at 5.5%. In FIG. 5B, the tube started to slip when the tube strain was 5.9%, and the tube was torn at 7.1%, and air leakage occurred from the split. As described above, according to the experiments by the inventors, it was difficult to prevent the pipe from detaching with respect to a pipe strain exceeding, for example, a yield strain of 8% for a polyethylene pipe, in a pipe without an in-core.

Japanese Patent No. 36553702

  In view of such a conventional situation, the present invention provides a plastic tube detachment prevention ring and a plastic tube that are inexpensive and can easily prevent detachment of the tube while preventing excessive deformation and breakage of the tube without using the in-core. It aims at providing a pipe joint.

  In order to achieve the above object, the plastic tube detachment prevention ring according to the present invention is characterized by a C-shaped ring body into which the plastic tube is inserted from the first opening, and an inner peripheral surface of the ring body. A plurality of teeth provided along a direction, a pair of flanges provided opposite to both ends of the ring body, and a fastening means for fastening the pair of flanges, wherein the diameter of the ring body is reduced by the fastening means. In the configuration in which the plurality of teeth are caused to bite into the plastic tube, the first teeth adjacent to the first openings of the plurality of teeth are lower than the other teeth, and the first teeth and the first teeth At least one of the other tooth pitches other than the first tooth pitch between the second teeth adjacent to the teeth is larger than the first tooth pitch.

  According to the above configuration, since the first tooth is adjacent to the first opening of the ring body, the adjacent tooth is only the second tooth. Therefore, the first tooth is more easily subjected to a pressing force on the tube due to the reduced diameter of the ring body than both teeth adjacent to the other teeth on both sides, and more easily bites into the tube than the other teeth. Further, the stress generated when the tube is about to be detached tends to concentrate on the teeth located on the first opening side. By making the first tooth lower than the other teeth, the amount that can bite into the tube is reduced, and excessive biting of the first tooth is suppressed. This prevents stress from concentrating on the first tooth, prevents damage to the tube such as tearing due to stress concentration, and disperses the load (detachment force) that the tube tries to disengage to other teeth. be able to. Then, at least one of the other tooth pitches excluding the first tooth pitch is made larger (wider) than the first tooth pitch. Since the biting of each tooth is affected by the repulsive force of the tube against the biting of the adjacent tooth, the influence is reduced as the tooth pitch is increased, and the tooth is likely to bite into the tube. Therefore, the teeth located in the intermediate portion of the ring body in the tube axis direction can easily bite into the tube, the balance of the amount of biting of each tooth is maintained, and the plurality of teeth come into contact with each other so as to bite into the tube. As a result, the detachment force of the tube is dispersed and applied to each tooth, and the entire plurality of teeth become resistance, thereby preventing detachment. In this way, each tooth equally bites into the tube and the plurality of teeth all come into contact with the tube, so that it is possible to prevent breakage and detachment of the tube without increasing the tightening torque. Application is not required and tightening work is facilitated.

  At least one of the other tooth pitches may be greater than or equal to the thickness of the plastic tube. By setting the thickness to be greater than or equal to the wall thickness, the repulsive force of the tube against the biting of the adjacent teeth can be suppressed, and the repulsive force to the adjacent teeth can be reduced to make the teeth bite more easily. As a result, the detachment force of the tube is distributed in a more balanced manner and is applied to each tooth, and the entire plurality of teeth become resistance, thereby preventing detachment more firmly.

  The angle of the base portions of the plurality of teeth is preferably 15 ° or more and 27 ° or less. When the angle is less than 15 °, the teeth are narrower in the tube axis direction where the detachment force acts, and the strength against the detachment force may be insufficient. On the other hand, if the angle exceeds 27 °, the teeth do not easily bite into the tube, the tube is further reduced in diameter, the tightening torque of the fastening means is increased, and workability is lowered. Furthermore, since the teeth do not sufficiently bite into the tube, the tube tends to slide out with respect to the detachment force. Preferably, the angle of the base portions of the plurality of teeth is 20 ° or more and 26 ° or less.

  The pair of flanges have convex portions that face each other and come into contact with each other by the diameter reduction of the ring body by the fastening means, and the height of the convex portions is such that the diameter reduction rate of the plastic tube is 96% or more and 97% or less. It is good to set so that. Thereby, the completion of the diameter reduction can be recognized by the contact of the convex portion, and the variation in the diameter reduction can be suppressed by the operator. Further, since the height may be adjusted, the amount of diameter reduction (diameter reduction ratio) can be easily adjusted. Moreover, if the diameter reduction ratio is in the range of 96% or more and 97% or less, a plurality of teeth can surely bite into the tube, and work can be performed with a relatively low tightening torque, so that workability is good.

  The height of the other teeth may be 10% or more and 20% or less of the wall thickness of the plastic tube. If it is the said numerical range, the intensity | strength of a pipe | tube will not be affected and the sliding (detachment | leave) of a pipe | tube can be prevented.

  The tube separation preventing ring according to any one of the above, for example, has at least five of the plurality of teeth, and other tooth pitches excluding the first tooth pitch and the second tooth pitch adjacent to the first tooth pitch. At least two of them may be larger than the first tooth pitch and greater than or equal to the wall thickness of the plastic tube. Moreover, when the said plastic pipe is a polyethylene pipe, it uses more suitably.

  In order to achieve the above object, the plastic pipe joint according to the present invention is characterized by a joint main body into which a plastic pipe is inserted, a packing attached to a receiving part of the joint main body, and pressing the packing against the receiving part. A retaining ring, a retaining ring that presses the retaining ring against the joint body, and a coupling means that couples the joint body, the retaining ring, and the retaining ring, wherein the retaining ring extends from the first opening to the plastic pipe. A C-shaped ring main body into which is inserted, a plurality of teeth provided on the inner peripheral surface of the ring main body along the circumferential direction, a pair of flanges provided opposite to both ends of the ring main body, Fastening means for fastening the pair of flanges, the first tooth adjacent to the first opening of the plurality of teeth is lower than the other teeth, the first tooth and the second adjacent to the first tooth No. between teeth At least one of the other tooth pitches except for the tooth pitch is larger than the first tooth pitch, and the plurality of teeth are bitten into the plastic tube by reducing the diameter of the ring body by the fastening means. There is.

  According to the features of the plastic pipe detachment prevention ring and the plastic pipe pipe joint according to the present invention, it is possible to prevent the pipe from detaching easily and inexpensively while preventing excessive deformation and breakage of the pipe without using the in-core. It became possible.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present invention.

It is a perspective view of the separation preventing ring according to the present invention. It is a disassembled perspective view of the separation preventing ring and pipe joint according to the present invention. It is a perspective view which shows the state which fastened the detachment prevention ring to the pipe | tube. (A) is sectional drawing of the state which fastened the detachment prevention ring, (b) is a figure which shows the amount of biting of the tooth of (a). It is a figure explaining the process of the separation prevention ring of FIG. It is a graph which shows the result of the tension test of the separation prevention ring of FIG. (A) is sectional drawing of the state which clamp | tightened the removal prevention ring of the comparative example, (b) is a figure which shows the amount of biting of the tooth | gear of (a). It is a figure explaining the process of the separation prevention ring of FIG. It is a graph which shows the result of the tension test of the separation prevention ring of FIG. It is the elements on larger scale of the tooth in other embodiments. It is a graph which shows the result of the tension test of the separation prevention ring of other embodiments. It is a figure which shows typically the example of the combination of the number of teeth, and a tooth pitch. It is a top view which shows the modification of a flange. It is sectional drawing of the state which clamped the conventional detachment prevention ring. It is a graph which shows the result of the tension test of the conventional detachment prevention ring, (a) shows tightening torque 112N, (b) shows the result of tightening torque 130N.

Next, the present invention will be described in more detail with reference to the accompanying drawings as appropriate.
As shown in FIGS. 1 to 3, the pipe joint 10 of the plastic pipe according to the present invention includes a joint body 3 into which the plastic pipe 2 is inserted, a packing 4 attached to the receiving portion 3 a of the joint body 3, and a packing 4. And a retaining ring 1 (stop ring) for pressing the press ring 5 against the joint body 3, and a connecting means 6 for connecting the joint body 3, the press ring 5 and the stop ring 1. In the present embodiment, a polyethylene pipe having a nominal diameter of 150 (hereinafter simply referred to as “pipe”) is used as the plastic pipe 2.

  As shown in FIGS. 1 to 3, the separation preventing ring 1 according to the present invention includes a C-shaped ring body 20 into which a pipe 2 is inserted from a first opening 21 and an inner peripheral surface 20 a of the ring body 20. The inner surface tooth group 25 constituted by a plurality of teeth provided along the circumferential direction, a pair of flanges 22 and 22 provided opposite to both ends in the circumferential direction of the ring body 20, and a pair of flanges 22 and 22 are fastened. Fastening means 24 is provided. The diameter of the ring body 20 is reduced by the fastening means 24 so that the inner surface tooth group 25 is digged into the pipe 2 to prevent the pipe from being detached. The fastening means 24 includes, for example, a T bolt 24a and a cap nut 24b.

  As shown in FIGS. 1 and 3, the pair of flanges 22 are provided with convex portions 23 that are in contact with each other by the diameter of the ring main body 20 by the fastening means 24 at opposing positions. In the present embodiment, a pair is provided at both ends of the flange 22 in the width direction (direction parallel to the tube axis direction). The pair of convex portions 23 a and 23 b protrude in a direction substantially orthogonal to the width direction of the flange 22. When the diameter of the ring body 20 is reduced by the fastening means 24, as shown in FIG. 3, the pair of flanges 22 and 22 approach each other, and the convex portions 23a and 23b abut against each other. With this contact, the completion of the diameter reduction (tightening by the fastening means 24) can be recognized, and variation in the amount of diameter reduction by the operator can be suppressed. The amount of diameter reduction (diameter reduction ratio) is adjusted by the height of the convex portion 23.

  In the present embodiment, the height of the pair of convex portions 23a and 23b (the amount of protrusion in the direction perpendicular to the width direction) is set so that the diameter reduction rate of the tube 2 is 96% or more and 97% or less. If it exceeds 97%, the diameter of the tube 2 is so small that the inner tooth group 25 described later does not sufficiently penetrate the tube 2, and the tube 2 slips with respect to the ring body 20 and cannot be reliably prevented from being detached. On the other hand, if it is less than 96%, the tightening work time of the fastening means 24 increases and the tightening bolt 24a becomes longer. In addition, since the tightening torque is also increased, workability is reduced.

  The inner surface tooth group 25 in this embodiment is comprised by the cyclic | annular 6 teeth T arranged in the pipe-axis direction with the below-mentioned tooth pitch P, as shown to Fig.4 (a). Here, the six teeth T have the teeth adjacent to the first opening 21 of the ring body 20 as the first teeth T1, and the second teeth T2, the third teeth T3,. Let it be tooth T6. Similarly, the tooth pitch P adjacent to the first opening 21 of the ring body 20 is defined as the first tooth pitch P1, and the second tooth pitch P2, the third tooth pitch P3,. The tooth pitch is P5. Hereinafter, the side of the first opening 21 of the ring body 20 is referred to as a front side F (or pipe side).

  The height H1 of the first tooth T1 is formed lower (shorter) than the height H2 of the other teeth T2 to T6. In the present embodiment, for example, the height H1 of the first tooth T1 is about half of the height H2 of the other teeth T2 to T6. Since only the second tooth T2 is adjacent to the first tooth T1, the influence of the adjacent tooth biting is small, and the first tooth T1 is easy to bite into the tube as compared with the other teeth. Therefore, if the height H1 of the first tooth T1 is equal to the height H2 of the second tooth T2, the first tooth T1 bites deeply, while the biting of the second tooth T2 becomes shallow. When the amount of biting of the first tooth T1 into the tube 2 increases, the split tube 2 is deformed and affects the biting of other teeth. Therefore, by making the first tooth T1 lower (shorter) than the other teeth T2 to T6, the maximum bite amount of the first tooth T1 is reduced, and the influence on the other teeth is suppressed. Further, the stress generated when the tube is about to be detached tends to concentrate on the first tooth T1. Therefore, if the first tooth T1 bites into the tube 2 too much, the tube may be broken (teared) by the stress. Therefore, by suppressing the maximum biting amount of the first tooth T1, damage to the tube at the time of preventing separation is also prevented.

  Here, the tooth height H <b> 2 of the second teeth T <b> 2 to T <b> 6 is set to 10% or more and 20% or less of the wall thickness W of the tube 2. If it is less than 10% of the wall thickness W, it is not possible to secure the depth of biting of the teeth that can counter the detachment force, and there is a risk of slippage with respect to the detachment force. On the other hand, if it exceeds 20% of the wall thickness W, teeth may bite into the tube 2 and affect the strength of the tube 2.

  When the first tooth pitch P1 is set to the pitch b, the second tooth pitch P2 and the fifth pitch P5 are set to the same pitch b, and the third and fourth tooth pitches P3 and P4 are set to the double pitch 2b. When the tooth pitch P is widened, the influence of the repulsive force of the tube on the biting of adjacent teeth is reduced, and the tooth T is likely to bite into the tube 2. In this way, by setting at least one of the other tooth pitches P2 to P5 other than the first tooth pitch P1 to be larger than the first tooth pitch P1, in particular, the tooth T in the axially intermediate portion of the ring body 20 is increased. Make the tube 2 easy to bite. Thereby, the balance of the amount of biting of each tooth is maintained, the detachment force of the tube is dispersed and loaded on each tooth, and the entire plurality of teeth become resistance, thereby preventing detachment.

  Further, a pitch wider than the first tooth pitch P <b> 1 may be equal to or greater than the wall thickness W of the tube 2. In the present embodiment, the pitch 2b of the third and fourth tooth pitches P3 and P4 is set to be approximately the same as the thickness of the pipe 2. If the thickness is less than the thickness of the tube 2, the teeth are difficult to bite due to the repulsive force of the tube 2 generated when adjacent teeth bite into the tube 2. For example, since the wall thickness of the polyethylene pipe having a nominal diameter of 150 is 16.4 to 17.5 mm, the pitch is about 2b = 16.4.

  Here, the separation preventing ring is made of ductile cast iron. As described above, since there is a wide pitch portion, as shown in FIG. 5, the exposed portion of the inner peripheral surface 20a of the ring body 20 can be used as it is, and the machining allowances C1 to C3 can be reduced. As a result, the cutting time can be reduced, the machining can be facilitated, and the production can be made at a low cost. On the other hand, in the comparative example shown in FIG. 8, since the pitch is narrow, the entire inside of the ring main body 20 has to be cut, the machining allowance C 'is large, and the machining is troublesome, and the manufacturing cost increases.

  Furthermore, in this embodiment, as shown in FIG. 4A, the angle θ1 of the tooth T is set to 25 °. The teeth T can bite into the tube 2 with a small force (tightening torque) on the tube 2. The angle θ1 of the tooth T is not limited to 25 °, and may be 15 ° or more and 27 ° or less. If the angle is less than 15 °, the teeth T may become thin, and the strength against the detachment force of the tube may be insufficient. If the angle exceeds 27 °, the teeth T are less likely to bite into the tube 2, the tube 2 is further reduced in diameter toward the inner diameter (center axis), the tightening torque of the fastening means 24 is increased, and workability is reduced. Furthermore, since the teeth T do not sufficiently penetrate the tube 2, slippage is likely to occur with respect to the detachment force of the tube. More preferably, it is 20 ° or more and 26 ° or less.

Here, the effect of this embodiment will be described with reference to FIGS.
FIG. 4B shows an actual measurement value of the biting amount D of each tooth T into the tube 2 in the separation preventing ring 1 (Example) shown in FIG. A symbol A in the figure indicates a root portion of the flange 22, and B indicates a point symmetrical with respect to the axis of the flange 22. FIG. 7B shows an actual measurement value of the biting amount D of each tooth T into the tube 2 in the separation preventing ring 1 ′ (comparative example) shown in FIG. The arrangement of the inner tooth group 25 is as shown in each figure (a). In both the examples and comparative examples, the height of the teeth is 1.4 mm for the first tooth T1 and 2.8 mm for the other teeth. Further, the tooth angle θ1 of the example is 25 °, and the comparative example is 30 °. Other conditions such as the tube 2, the tightening means 24, and the diameter reduction rate (96.5%) are the same.

  In the embodiment shown in FIG. 4B, at the point A, the second tooth T2 to the sixth tooth T6 bite into the same extent, and the first tooth T1 bites into 1.6 mm. Further, at the point B, which is substantially symmetrical with the point A, the sixth tooth T6 bites into the second tooth T2 to the sixth tooth T6, although it is slightly larger, and the first tooth T1 bites into 0.6 mm. Thus, in the Example, each tooth T1-6 bites into about the same height as the set tooth height, and the other teeth T2-6 bite into the same depth. As described above, in the embodiment, the tooth T bites into the tube 2 at the depth D substantially equal to the heights H1 and H2 of the set teeth T, so that the entire inner surface tooth group 25 bites into the tube 2 so that the tube 2 Touch the outer surface. Moreover, since the teeth T2 to T6 have the same depth, the detachment force of the tube is dispersed and loaded on each tooth. Therefore, without the concentration of stress, the detachment force of the tube is dispersed and applied to each tooth, and the entire plurality of teeth become resistance, thereby preventing the detachment of the tube.

  On the other hand, in the comparative example shown in FIG. In particular, the amount of biting of the second and third teeth t2, t3 is as large as 2.4 mm and 2.0 mm, and the amount of biting of the fourth and fifth teeth t4, t5 on the inside (joint body 3 side) is 1.4 mm. , 1.5 mm and the difference is large. Thus, in the embodiment, since the amount of biting of the teeth (fourth and fifth teeth t4, t5) in the intermediate portion of the separation preventing ring 1 ′ is small, the stress with respect to the separation force of the tube is concentrated on the front side F. Become. For this reason, it is impossible to counter the detachment force as a whole, and stress may concentrate and the tube may be damaged. Further, since the amount of tooth biting varies greatly, the internal tooth group 25 as a whole cannot counter the detachment force and cannot sufficiently prevent the detachment of the tube. In addition, the amount of biting of the first tooth T1 at the point A is larger than the tooth height H1. This is because the flat portion 34 on the front side F not adjacent to the other teeth of the first tooth T1 compresses the tube 2 and the first tooth T1 bites into the tube 2.

  Moreover, the tightening torque of the example was 86 N · m, and the comparative example was about 110 N · m, and the tightening torque could be reduced by about 20%. That is, it was found that the pipe detachment prevention performance was improved while improving workability. Since the tightening torque can be reduced, it is possible to prevent deterioration of workability in a low-temperature environment (−5 ° C. to 5 ° C.) such as a cold district where the polyethylene pipe is hard and has a reduced diameter.

  Further, in order to confirm the performance of the separation preventing ring, a tensile test was performed by applying an internal pressure of 0.5 Mpa. FIG. 6 shows the results of the example, and FIG. 9 shows the results of the comparative example. In this example, as shown in FIG. 6, when the tube started to slip at a tube strain of 8.4% and was 20 mm away, it reached 9.8%. At the stage where the test was completed, the tightening portion side (flange 22 side) of the separation preventing ring 1 was not largely broken. Also, no air leaks could be confirmed. On the other hand, in the comparative example, when the tube strain was 5%, the air began to slip when 7% started to leak. Thus, it has been found that the deformation (breakage) of the tube can be prevented and the detachment of the tube can be sufficiently prevented.

Finally, reference is made to the possibilities of other embodiments of the invention. In addition, the same code | symbol is attached | subjected to the member similar to the above-mentioned embodiment.
In the said embodiment, as shown in FIG. 4, the tooth | gear T was formed from the root to the front-end | tip part at a fixed angle. However, the shape is not limited to this, and may be a shape as shown in FIG. The angle θ1 of the proximal end portion of the tooth T shown in FIG. 10 and the angle θ2 of the distal end portion may be made different to satisfy θ2> θ1. Thereby, the strength of the tip can be improved. Also in this embodiment, as shown in FIG. 11, the result equivalent to the said embodiment was obtained. In the example of FIG. 10, θ2 is 30 °.

  In the above embodiment, the third and fourth tooth pitches P3 and P4 are twice the pitch b of the other tooth pitches P. However, the present invention is not limited to this. For example, as shown in FIG. 12A, for example, the third tooth pitch P3 can be set to the pitch 3b. Of course, the fourth tooth pitch P4 may be the pitch 3b. Moreover, as shown in the figure (b), it is good also considering the 3rd-5th tooth pitch P3-5 as the pitch 2b. Furthermore, as shown in FIG. 5C, the number of teeth T may be five, and the third and fourth tooth pitches P3 and P4 may be twice (2b) the first and second tooth pitches P1 and P2. Is possible. Furthermore, the fifth tooth T5 in FIG. 5A can be omitted to have five teeth, and the tooth pitch between the fourth tooth T4 and the sixth tooth T6 can be 2b. That is, there are at least five teeth, and at least two of the first tooth pitch and the other tooth pitch excluding the second tooth pitch adjacent to the first tooth pitch are larger than the first tooth pitch. There should be. Furthermore, in each said embodiment, although the wide pitch was made into 2 times (2b) of the pitch amount b of the 1st tooth pitch P1, it should just be 1.8 times (1.8b) or more. If it is smaller than 1.8 times, the load concentrates on the front F teeth for a large strain and cannot be distributed to each tooth. For example, it may be about 2 to 3 times the first tooth pitch P1.

  In the above embodiment, a polyethylene pipe having a nominal diameter of 150 has been described as an example of the plastic pipe 2. However, the nominal diameter of the pipe is not limited to 150, and can be applied to pipes having nominal diameters of 100 and 200. Moreover, it is not limited to a polyethylene pipe, and is suitably used for a pipe that is relatively deformed and needs to be fitted with an in-core, and does not require an in-core fitted.

  In the above embodiment, the pair of flanges 22 is provided with a pair of substantially rectangular convex portions 23 at both ends thereof (convex portions 23a and 23b). However, the aspect of the convex part 23 is not restricted to the said embodiment. For example, as shown to Fig.13 (a), you may comprise so that all the opposing parts of a pair of flange 22 may contact | abut. Further, as shown in FIG. 5B, it is possible to provide three sets (a plurality of sets) of the convex portions 23. Furthermore, as shown in FIG. 5C, the convex portion 23 having the same height may be provided only on one side. Thus, by providing the convex portion 23 (contact portion) so that at least both ends of the pair of flanges 22 along the tube axis direction A are in contact with each other, the detachment force of the tube intersects the tube axis direction A. Even if acting in the direction, uneven deformation at both ends of the flange 22 is suppressed, so that the pair of flanges 22 and 22 are prevented from opening and holding of the pipe 2 is prevented from loosening.

  The separation preventing ring according to the present invention can be used for a pipe joint such as a plastic water pipe buried in the ground.

1: separation prevention ring (stop ring), 2: plastic pipe, 3: joint body, 3a: receiving portion, 4: packing, 5: push ring, 6: coupling means, 10: pipe joint, 20: ring body, 20a : Inner peripheral surface, 21: first opening, 22: flange, 23, 23a, 23b: convex portion, 24: fastening means, 24a: bolt, 24b: nut, 25: inner tooth group, 30: base, 32: tip Part, 33: recessed part, 34: flat part, A: pipe axis direction, C: cutting margin, D: depth (tooth biting amount), P, p: tooth pitch, H1, H2, h: height, T, t: tooth, W: wall thickness, θ1: base angle, θ2: tip angle

Claims (9)

A C-shaped ring main body into which a plastic tube is inserted from the first opening, a plurality of teeth provided on the inner peripheral surface of the ring main body along the circumferential direction, and opposite both ends of the ring main body A plastic tube detachment prevention ring comprising a pair of flanges provided and a fastening means for fastening the pair of flanges, wherein the plurality of teeth bite into the plastic pipe by reducing the diameter of the ring body by the fastening means. There,
A first tooth adjacent to the first opening of the plurality of teeth is lower than the other teeth;
At least one of the other tooth pitches excluding the first tooth pitch between the first tooth and the second tooth adjacent to the first tooth is larger than the first tooth pitch. Prevention ring. The plastic tube detachment prevention ring according to claim 1, wherein at least one of the other tooth pitches is equal to or greater than a thickness of the plastic tube. The plastic tube detachment prevention ring according to claim 1 or 2, wherein an angle of a base portion of the plurality of teeth is 15 ° or more and 27 ° or less. The plastic tube detachment prevention ring according to any one of claims 1 to 3, wherein an angle of a base portion of the plurality of teeth is 20 ° or more and 26 ° or less. The pair of flanges have convex portions that face each other and come into contact with each other by the diameter reduction of the ring body by the fastening means, and the height of the convex portions is such that the diameter reduction rate of the plastic tube is 96% or more and 97% or less. The plastic pipe detachment prevention ring according to any one of claims 1 to 4, which is set to be The height of the other teeth is 10% or more and 20% or less of the wall thickness of the plastic tube, The plastic tube detachment prevention ring according to any one of claims 1 to 5. The plurality of teeth has at least five, and at least two of the first tooth pitch and the other tooth pitch excluding the second tooth pitch adjacent to the first tooth pitch are larger than the first tooth pitch. The plastic pipe detachment preventing ring according to any one of claims 1 to 6, wherein the ring is not less than a thickness of the plastic pipe. The said plastic pipe is a polyethylene pipe, The separation prevention ring of the plastic pipe in any one of Claims 1-7. A joint body into which a plastic pipe is inserted, a packing attached to a receiving portion of the joint body, a push ring that presses the packing against the receiving portion, a retaining ring that pushes the push ring against the joint body, A pipe joint of a plastic pipe provided with a connecting means for connecting a joint body, the push ring and the retaining ring,
The retaining ring includes a C-shaped ring-shaped ring body into which the plastic tube is inserted from a first opening, a plurality of teeth provided along the circumferential direction on the inner circumferential surface of the ring body, and the ring body. A pair of flanges provided opposite to both ends, and a fastening means for fastening the pair of flanges,
A first tooth adjacent to the first opening of the plurality of teeth is lower than the other teeth;
At least one of the other tooth pitches excluding the first tooth pitch between the first tooth and the second tooth adjacent to the first tooth is greater than the first tooth pitch,
A pipe joint of a plastic pipe that causes the plurality of teeth to bite into the plastic pipe by reducing the diameter of the ring body by the fastening means.

Images