JP2685105B2 - Pipe fittings - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pipe joint used for transporting water, hot water, etc., which is preferably applied mainly to a plastic pipe, and particularly to a pipe joint. The purpose is to effectively prevent damage to the pipe and improve its durability.

(Prior Art) As a pipe joint used for joining plastic pipes required to withstand pressure, for example, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent Publication No. 52-149620.

As shown in the axial sectional view in FIG. 8, the inner diameter enlarging portion 3 is provided at the end portion on the pipe inserting side of the socket 2 which allows the insertion of the pipe 1, and the inner diameter enlarging portion is provided. The pipe holding ring 4, the backup ring 5, and the seal ring 6 are sequentially arranged from the front side in the insertion direction of the pipe 1, while the cap 4, which is screwed onto the outer periphery of the socket 2, causes the respective rings 4, 5, 6 to be inserted. In addition, the pipe retaining ring 4 is provided with a plurality of claws 8 which are located at intervals in the circumferential direction thereof and which face the front side in the insertion direction of the pipe 1.

In such a pipe joint, the pipe 1 is inserted into the socket under elastic deformation of the pawls 8 of the holding ring 4 in the expanding direction, so that the connection of the pipe 1 to the joint is extremely easily and reliably performed. It can be carried out.

Here, in such a connected state of the pipe 1, the frictional force between the pipe 1 and each claw 8 or each claw 8
The bite into the pipe 1 effectively prevents the pipe 1 from coming out of the pipe joint,
This is especially true when the claws 8 of the retaining ring 4 firmly engage the circumference of the pipe 1 due to the external force in the pulling direction of the pipe 1, which is in the connected state, and is made of plastic. It is remarkable.

Under such a connected state of the pipe 1, the seal ring 6 functions to prevent leakage of the internal fluid, the backup ring 5 functions to protect the seal ring 6, and the cap 7 functions. , Each ring 4,
It functions to prevent the escape of 5 and 6.

Also, as shown in the figure, 9 indicates a sleeve, which is inserted into the tip of the pipe 1 to maintain the roundness of the pipe 1 when the pipe 1 is made of plastic, and The claw 8 functions to make the amount of bite into the pipe 1 constant.

(Problems to be Solved by the Invention) However, in such a conventional pipe joint, in the case where the pipe 1 is made of plastic, in other words, as the external force acting in the pipe 1 increases in the drawing direction,
As the pipe 1 is displaced relative to the joint in the drawing direction, the amount of the pawl 8 of the retaining ring 4 biting into the pipe 1 gradually increases, and the pawl 8 eventually penetrates the pipe wall. , A fluid pressure on the pipe 1, an action such as an external pulling force, a pipe tear caused by vibration of the pipe, or the like is relatively early from the penetrating portion of the pipe wall in the circumferential direction and / or the axial direction of the pipe 1. Progressing, the leakage of the transport fluid from the cracked portion, plastic pipe 1
There is a problem that cracks and the like are likely to occur, which is particularly serious when the pipe joint to which the plastic pipe 1 is connected is applied to a hot water supply system.

Therefore, it was proposed to reduce the number of pawls of the retaining ring by about 30% from that of the conventional pipe joint to prevent mutual connection of the penetrating portions of the pawls to the pipe wall. According to this, there was another problem that the force acting on each claw increased and the claw was damaged, and at the ambient temperature of about 80 ° C, the pull-out test of the plastic pipe connected to the joint was performed. As a result, it was confirmed that the tensile strength was about 30% lower than that of the conventional pipe joint.

The present invention advantageously solves the above-mentioned problems of the prior art, and sufficiently prevents the pawls of the retaining ring from penetrating the pipe wall to prevent leakage of transport fluid, tearing of the pipe end, and the like. (EN) A pipe joint that can be prevented extremely effectively over a long period of time.

(Means for Solving the Problem) In particular, the pipe joint of the present invention is provided with a plurality of pawls, which are located at intervals in the circumferential direction of the pipe holding ring and are directed to the front side in the insertion direction of the pipe. The projections are provided in the vicinity of the tips of the claws and project in at least one of the width direction and the thickness direction of the claws.

(Operation) In this pipe joint, in the same way as described for the conventional pipe joint, when an external force in the pulling direction acts on the pipe when the plastic pipe is connected thereto, Each claw of the retaining ring
Until the projection provided there comes into contact with the pipe surface, it will be pierced into the pipe wall, but further piercing is reliably prevented by the projection, so in relation to the wall thickness of the pipe, By appropriately selecting the forming position of the protrusion, the depth of the claw that bites into the pipe wall can always be made proper, and therefore, the claw that penetrates the pipe wall causes the split to the pipe. The occurrence of scratches can be prevented, and leakage of the transport fluid from the cracks, breakage of the pipe end, and the like can be prevented extremely effectively.

Here, in order to smooth the biting of the tip of the claw into the pipe, it is preferable to make the tip sharp, while in order to reliably prevent the biting of the protrusion into the pipe, It is preferable that the tip surface is flat or curved.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a pipe holding ring which is an essential part of the present invention.

The overall structure of the pipe joint according to the present invention is
Since it is almost the same as that of the pipe joint shown in the figure, its illustration is omitted here.

Retaining ring as shown in the figure
In 11, a plurality of claws 13 projecting from the ring-shaped portion 12 and located at predetermined intervals in the circumferential direction thereof and bent forward in the insertion direction of the pipe are provided, and each claw 13 thereof is provided. As is clear from the front view shown in FIG. 2, each projection 14 is provided near the tip of the projection 13 so as to project to both sides of the claw 13 in the width direction.

Here, the formation positions of the protrusions 14 can be appropriately selected in relation to the pipe wall thickness and the required depth of the pawl 13 to bite there.

FIG. 3 is a front view showing another example of a protrusion projecting to the side of the claw, and FIG. 3 (a) shows the front contour shape of each protrusion 15 projecting to both sides of the claw 13. It is formed in a substantially "U" shape.

Further, FIG. 3 (b) is a view in which the protrusions 16 projecting from the respective claws 13 are continuous with each other between the adjacent claws, and FIG. 3 (c) shows one side of the claws 13. The protrusion 17 is provided only on the.

According to the pipe retaining ring 11 configured as described above, in the state where the plastic pipe is connected to the joint,
When an external force is applied to the pipe in the pulling direction, the tip of each claw will bite into the wall of the pipe only in an appropriate amount as required, but if it bites further, the outer surface of the pipe and the protrusion The contact with the tip surfaces of the parts 14, 15, 16, 17 is surely prevented.

Therefore, here, there is no possibility that the claw 13 penetrates into the pipe wall, and therefore, the occurrence of a crack in the pipe due to the concentration of stress on the penetrating portion, and hence the leakage of the transport fluid from the crack, the end of the pipe. Tear of parts will be sufficiently prevented.

By the way, using the pipe retaining ring 11 shown in FIG.
When the pull-out strength of the pipe was measured when the inner diameter was 13 mm and the ambient temperature was 80 ° C, it was increased by about 15% compared with the case where the conventional joint was used.

Here, it is preferable that the tip of each claw 13 be sharpened with respect to the pipe outer peripheral surface 1a as illustrated in FIG. 4 so that the claw 13 easily bites into the pipe wall. By making the tip surfaces of the respective projections 14, 15, 16, 17 into a flat surface shape or a curved surface shape that makes surface contact with the pipe outer peripheral surface 1a, as illustrated in FIG. 5,
Reliably prevent the protrusions from biting into the pipe wall.

FIG. 6 is a side view illustrating a protrusion protruding in the thickness direction of the claw, for example, by bending a part of the component of the claw 13 to the front surface side or the back surface side of the claw 13, or The projection 18 is formed by fixing or adhering another member to the front surface or the back surface of the claw 13.

It is needless to say that any of these protrusions 18 can sufficiently prevent the claw 13 from biting into the pipe wall by a predetermined amount or more, as in the above-described respective protrusions.

Further, FIG. 7 is a view showing a protrusion 19 which is formed by bending a part of the tip end portion of the claw 13 so as to project to one side of the claw 13 and also to the surface side of the claw 13. Yes,
With such a protrusion 19, it is possible to more reliably prevent an excessive cutting of the claw 13 into the pipe wall.

The present invention has been described above based on the illustrated examples, but the projections according to the present invention do not necessarily have to be provided on all the claws, and may be provided at intervals of a predetermined distance in the circumferential direction, or at intervals of one or more. It is possible.

(Effect of the invention) Thus, according to the present invention, a protrusion is provided in the vicinity of the tip of the claw of the pipe holding ring, and the protrusion prevents the claw from excessively biting into the pipe wall, so that It is possible to sufficiently prevent the leakage of the transport fluid and the breakage of the end portion of the pipe, and remarkably improve the durability of the pipe.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a pipe holding ring which is an essential part of the present invention, FIG. 2 is a front view showing a projection of the pipe holding ring shown in FIG. 1, and FIG. FIG. 4 is a side view illustrating the tip end of the claw, FIG. 5 is a side view illustrating the tip end surface of the protrusion, and FIGS. FIG. 8 shows another example, and FIG. 8 is an axial direction sectional view showing a conventional example. 1 …… Pipe, 1a …… Pipe outer peripheral surface 2 …… Socket, 3 …… Inner diameter expansion part 5 …… Backup ring 6 …… Sealing, 7 …… Cap 11 …… Pipe retaining ring, 12 …… Ring-shaped part 13 ...... Claws 14,15,16,17,18,19 …… Projections

Claims (1)

(57) [Claims] 1. A socket for allowing insertion of a pipe, a pipe holding ring, a backup ring, and a seal ring, which are sequentially arranged in an enlarged inner diameter portion of the socket from a front side in a direction of insertion of the pipe, and an outer periphery of the socket. A pipe joint provided with a cap that is screwed together to prevent the respective rings from coming off, and a plurality of pipe coupling rings that are located at intervals in the circumferential direction of the pipe retaining ring and that face the front side in the insertion direction of the pipe. The pipe joint is provided with the claws and the projections are provided in the vicinity of the tips of the claws.