JP2010019395A - Joint for plastic resin pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To connect pipes by a single operation by only making only each connection pipe end engaged with a joint and by manually tightening a cap, and to prevent the pipes from being co-rotated when turning and screwing the cap. <P>SOLUTION: A joint body 8 is covered and screwed while keeping a clearance dg layer to an inner core 9 having a water flow hole H9 at an inner circumference and an O-ring 4 at an outer circumference, the cap 3 inclusion-engaged with a diameter contracting fixing ring 5 is temporarily screwed to an end of the joint body 8, a plastic resin pipe 12 is fit into a clearance dg in a form of covering the inner core 9 from the inside of the cap 3, the cap 3 is turned and advanced, the fixing ring 5 is thereby diameter-contracted to press a pipe 12 outer circumferential face 12c, the plastic resin pipe 12 is pressed water-tightly, and locking holding free from pulling-off is attained by this manner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pipe joint for connecting a plastic resin pipe of a water supply pipe or a hot water supply pipe.

Conventionally, cast iron pipes and steel pipes have been used for water supply and hot water supply pipes, but in recent years, polyethylene, crosslinked polyethylene, polybutene, ethylene, etc. have been used in view of corrosion resistance, earthquake resistance, hygiene, workability and cost. Octene. Pipes molded from plastic resins such as copolymers have come to be used as piping for water supply and hot water supply, floor heating, and heat medium for road heating in detached houses, apartment houses, industrial buildings, etc. It was.
Therefore, the joints of Conventional Examples 1 and 2 have been proposed as pipe joints effective for connecting plastic resin pipes.

8A and 8B are pipe joints of Conventional Example 1 cited as Patent Document 1. FIG. 8A is a side sectional view of a state before connection, and FIG. 8B is a side sectional view of a connection state.
That is, the pipe joint of Conventional Example 1 (FIG. 8) is composed of a joint body, a split ring, and a cap nut. As shown in FIG. 8 (A), the joint body is a male screw having a threaded surface on the outer peripheral surface. An inner core portion protrudes from the tube portion, and a locking notch for holding the inner peripheral surface of the plastic tube is disposed over the entire length on the outer peripheral surface of the inner core portion.

In addition, the split ring to be fitted to the outer peripheral surface of the plastic pipe is provided with a crack portion for reducing the diameter, and a protrusion is provided on the inner peripheral surface, and the outer peripheral surface provided with a tapered surface portion on the outer end portion. In order to reduce friction, a fluororesin coating layer is formed.
In addition, the cap nut is provided with a female thread portion for screwing onto the outer periphery of the male screw pipe portion on the front inner peripheral surface, and a tapered surface portion for reducing the diameter of the split ring on the rear inner peripheral surface. A film layer of fluororesin is formed on the tapered surface portion.

  When connecting the plastic pipe to the joint body, as shown in FIG. 8 (A), a cap nut is fitted on the outer periphery of the connecting end of the plastic pipe, and then a split ring is fitted, as shown in FIG. 8 (B). The plastic pipe connection part is covered and fitted to the base end of the inner core part of the joint body, the plastic pipe tip is brought into contact with the base end of the inner core part, and then the cap nut is screwed forward and fastened to the joint body. The cap nut pushes the split ring to the proximal end of the inner core portion, and the tapered surface of the cap nut pushes and compresses the split ring, so that the plastic pipe is cut in the inner core portion located on the inner peripheral surface. It is sandwiched and held by the portion and the protrusion of the split ring located on the outer peripheral surface.

9A and 9B are explanatory diagrams of Conventional Example 2 cited as Patent Document 2, in which FIG. 9A is a sectional view of a plastic pipe fastened state, and FIG. 9B is an enlarged view of a main part of FIG. .
That is, in Conventional Example 2, as shown in FIG. 9, the inner peripheral surface recess of the joint body includes an O-ring, an auxiliary ring, and a locking ring inside the front end, and the outer peripheral surface is reduced in diameter backward. A diameter-reducing pressing ring having a tapered portion is sequentially arranged, and a cap having a tapered portion aligned with the tapered portion of the pressing ring on the inner periphery of the front end is temporarily screwed into the joint body.

When connecting the pipe, the connecting end of the plastic pipe is fitted along the inner peripheral surface of the cap and the inner peripheral surface of the joint body, and the cap is screwed and fastened to the joint body, so that the taper surface of the cap and the pressure ring The pressure ring is advanced and contracted by the cooperative action with the taper surface, and the pressure ring and the locking ring press and secure the outer peripheral surface of the plastic tube, and the O ring is pressed by the advance of the auxiliary ring by the advance of the pressure ring. The outer peripheral surface of the plastic pipe is sealed by the radial displacement of the O-ring, and the outer periphery of the plastic pipe is pressed and held by the locking ring and the pressing ring. The plastic pipe is inserted into the pipe joint. This is a pipe joint that can be connected with a single touch of a plastic pipe by simply rotating the cap.
JP-A-9-229258 Japanese Patent Application Laid-Open No. 11-141765

  In the pipe joint of Conventional Example 1 (FIG. 8), due to the reduced diameter of the split ring, the protrusion on the inner peripheral surface of the split ring bites into the outer peripheral surface of the plastic pipe, The joint action prevents the plastic pipe from being pulled out, and the joint rotation of the plastic pipe in the fastening action of the pipe joint is applied to the outer peripheral surface of the split ring and the tapered surface of the inner periphery of the cap nut. Although it can be suppressed by sliding between the coating layers of the fluororesin, there is a problem in workability because the cap nut and the split ring are individually attached when the plastic pipe is inserted and joined.

That is, in the pipe joint of the conventional example 1, the split ring is accommodated in the cap nut, and the cap nut is temporarily screwed into the joint main body and is carried to the site.
(I). Disassemble into joint body, split ring and cap nut.
(B). As shown in FIG. 8A, the cap nut and the split ring are fitted into the plastic tube with a space therebetween.
(C). A plastic tube is attached to the base end of the inner core part.
(D). Move the split ring to the base end of the inner core.
(E). Put the cap nut on the split ring and screw it onto the joint body.
As described above, the connection work is performed in the work steps (A) to (E), and the connection of the pipes is complicated and takes time.

Moreover, in the pipe joint of the conventional example 1 (FIG. 8), if the cap nut is over-tightened to prevent water leakage, the plastic pipe is over-compressed by a plurality of notches having an inner core surface. The outer peripheral surface is deformed due to over-compression by the split ring ridge, and after a long period of time, creep deformation (deformation that increases with time without applying stress) may occur, and the water stoppage may be lowered. There is.
Further, the connecting portion at the tip of the plastic pipe is deformed by the biting of the plurality of notch portions of the inner core portion with respect to the inner peripheral surface and the biting ridge portion of the split ring with respect to the outer peripheral surface, so that the water leakage preventing state is maintained. Therefore, the plastically deformed connecting portion of the plastic pipe cannot be used for the pipe connection again.

  In the pipe joint of Conventional Example 2 (FIG. 9), as shown in FIG. 9 (A), the inner diameter of the cap body includes an O-ring, an auxiliary ring, a locking ring, and a pressing ring. This is a one-touch type pipe joint in which a plastic pipe is inserted into a pipe joint that has been temporarily screwed into the joint body, and a cap is screwed and tightened. For this reason, a winding rod is attached, and the pipe cross section of the connecting portion for insertion into the pipe joint is deformed into an elliptical shape.

  Therefore, if the plastic pipe connecting part is inserted into the inner diameter part of the cap at random, the pipe tip collides with the O ring exposed in the inner diameter direction, and the O ring is fitted in the inner peripheral groove of the joint body. In addition, the O-ring has a desired sealing performance when it is connected to a plastic pipe by giving the action of pulling in the inner circumferential direction and dropping the O-ring from the insertion groove, cutting it, or deforming it. There is a fear of leaking water.

If water leakage occurs in the pipe joint, remove the cap, remove the plastic pipe, and once remove the pressing ring, locking ring, auxiliary ring, and O-ring, then reset the pipe joint again, and then remove the plastic pipe. Will be inserted.
Therefore, the connecting operation of the plastic pipe with the winding rod is a difficult operation requiring attention, and the workability is poor.
For example, even if the plastic pipe can be inserted into the pipe joint without damaging the O-ring, the cap tightening work must be performed so that the inner diameter of the cap is in contact with the outer peripheral surface of the plastic pipe, and the final tightening is the pressing ring By applying a rotational pressing force to the plastic tube, the plastic tube rotates with the pressing ring and partially twists, causing buckling or stress distortion in the plastic tube, which impairs the durability of the plastic tube itself. is there.
The present invention provides an innovative one-touch connection type plastic pipe joint that solves or improves the problems of the conventional examples 1 and 2.

  As shown in FIG. 1, for example, the pipe joint for plastic resin pipe according to the present invention has a joint body 8 mounted on the outer periphery of a tubular inner core 9, a cap 3 is attached to the end of the joint body 8, and a pipe 12 Is a pipe joint in which the plastic resin pipe 12 is connected to the inner core 9 through the cap 3 by one-touch operation by turning the cap 3, and the inner core 9 is a pipe having a water passage hole H9. The outer peripheral surface 9c includes a threaded surface 9S for screwing the joint body 8 and an O-ring 4 fitted in the locking groove 9G. The joint body 8 is in the form of a pipe and has an inner periphery. The surface 8d is provided with a screw surface 8S 'for screwing the inner core 9 and the outer peripheral surface 8c is provided with a screw surface 8S for screwing the cap 3, and an end portion of the inner peripheral surface has a tapered surface t8 that expands outward. The cap 3 is provided on the rear surface 3B. It includes an insertion hole H3, a front surface of the inner peripheral surface is provided with a screw surface 3S that is screwed with a screw surface 8S of the joint body, and a rear surface of the inner peripheral surface is provided with a tapered surface t3 that is reduced in diameter outwardly. Has a tapered surface ta aligned with the tapered surface t8 of the joint body, and a tapered surface tb aligned with the tapered surface t3 of the cap 3 on the outer periphery, and a fixing ring 5 having a slit 5G for reducing the diameter. The plastic resin pipe 12 is inserted into the gap dg between the inner core 9 and the joint body 8 from the insertion hole H3 of the cap 3, and the fixing ring 5 is reduced in diameter by screwing and fastening the cap 3. Thus, the plastic resin pipe 12 is pressed against the outer peripheral surface 9c of the inner core 9 in a watertight manner.

  In this case, although the material of each member which comprises a pipe joint is not ask | required, since it will produce problems, such as rust and a metal elution, if it is made of gunmetal or brass, a plastic resin material is preferable. The joint body 8 and the inner core 9 are molded articles of polyetherimide resin (trade name: Ultem resin), and the fixing ring 5 is a molded article of polyphenylene oxide resin (trade name: noryl resin).

  Further, the gap dg between the outer peripheral surface 9c of the inner core 9 and the inner peripheral surface 8d of the joint body 8 may be of a size that allows the plastic resin pipe 12 to be inserted. The formation of the gap dg is as shown in FIG. The joint body inner peripheral surface 8d may be smooth and may be formed by the diameter-expanded step portion dg of the inner core outer peripheral surface 9c. The inner core outer peripheral surface 9c may be formed as a smooth surface, or although not shown, step protrusions for forming the gap dg may be disposed from both the joint body inner peripheral surface 8d and the inner core outer peripheral surface 9c. The formation of the gap dg may be appropriately selected and determined from the production surface of the pipe joint.

The plastic resin pipe 12 that employs a pipe joint is preferably a flexible plastic pipe, and is typically made of ethylene. Octene. It is made of a copolymer (PE-RT) resin.
The O-ring 4 is typically a circular ring with a 1.9 mm thickness of JISB2401 nitrile rubber having excellent wear resistance and heat resistance. The plastic resin pipe 12 having an outer diameter R12 having a nominal diameter of 13 mm of 17 mm and an inner diameter R12 ′ of 13 mm has a tolerance of ± 0.15 mm, so the thickness is 1.9 mm. The O-ring 4 may be configured to protrude 0.5 mm from the outer peripheral surface 9c of the inner core 9 having an outer diameter R9 'of 12.6 mm.
Since the O-ring 4 corresponds to the tolerance of the diameter of the plastic resin pipe 12 with sufficient sealing performance, typically, two O-rings are arranged, and each O-ring 4 is within the pressing area of the fixing ring 5. Arrangement is sufficient.

Further, the fixing ring 5 that acts to reduce the diameter can be maintained by being loosely fitted in the cap 3, and in the free state, the pipe 12 penetrating from the insertion hole H3 of the cap 3 may be penetrated.
In addition, the front tapered surface ta, the rear tapered surface tb, and the slit 5G in the form of a split groove for diameter reduction of the fixing ring 5 are caused by the fixing ring 5 moving forward with the advancement of the cap 3. The front tapered surface ta is the tapered surface t8 of the joint body 8 and the rear tapered surface tb is pressed and compressed by the tapered surface t3 of the cap 3 to press the plastic resin pipe 12 against the outer peripheral surface 9c of the inner core 9 in a watertight manner. What is necessary is just to be a relational dimension that can be done.

  Then, the relationship between the taper surface tb of the fixing ring 5, the taper surface t3 of the cap 3 and the diameter-reducing slit 5G is such that the cap 3 is advanced and screwed into the joint body 8, and the rotation of the cap 3 becomes hard. At this stage, the structure in which the fixing ring 5 does not overpress the outer peripheral surface 12c of the plastic resin pipe 12, that is, the flexible plastic resin pipe 12 can be pressed against the outer peripheral surface of the inner core 9 in a watertight manner. Typically, for a plastic resin pipe 12 having an outer diameter R12 of 17 mm, the diameter R5 ′ of the insertion hole H5 of the fixing ring 5 is 17.6 mm, and the width of the slit 5G is 2 .5 mm.

  Accordingly, the plastic resin pipe 12 is connected to the pipe joint of the present invention by inserting the pipe 12 through the insertion hole H3 at the outer end (rear end) of the cap as shown in FIG. The holding ring 5 and the inner core 9 outer peripheral surface 9c are inserted through the gap between the outer peripheral surface 9c of the inner core 9 and the inner peripheral surface 8d of the joint body 8 until the innermost surface step d9. The cap 3 is screwed forward on the joint body 8 simply by rotating the cap 3 manually, and at the same time, the fixing ring 5 is caused by the cooperative action of the taper surface t3 of the cap 3 and the taper surface t8 of the joint body 8. By reducing the diameter, the inner peripheral surface 12d of the pipe 12 is pressed against the O-ring 4 on the outer periphery of the inner core and pressed tightly, and the connection fastening of the plastic resin pipe 12 to the pipe joint can be performed by a one-touch method.

Due to the presence of the inner core 9, even in the case of the plastic resin pipe 12 with a winding rod, the insertion into the pipe joint is a guide insertion in a perfect circle shape, for example, the pipe tip collides with the O-ring protrusion. However, the tip of the pipe 12 slides on the O-ring 4 without applying a stress that causes the O-ring 4 to be elastically expanded and pulled out from the locking groove 9G, so that the O-ring 4 is deformed or damaged. Does not occur.
Further, at the initial fastening stage of the cap 3, the fixing ring 5 advances by sliding rotation with respect to the outer peripheral surface 12 c of the pipe 12 due to the rotation of the cap 3, and advances without causing twisting of the pipe 12.

Then, from the stage where the fixing ring 5 starts to reduce the diameter and gradually increases the pressing friction with the outer peripheral surface 12c of the pipe 12, the fixing ring 5 has a pressing friction force between its own tapered surface ta and the tapered surface t8 of the joint body. The taper of the rear part is a cooperative action of the increase in the pressure, the increase in the pressing friction force of the pipe inner peripheral surface 12d to the outer peripheral surface 9c of the inner core 9, and the increase in the locking force on the pipe outer peripheral surface 12c at both side edges of the slit 5G. The rotational friction force from the cap 3 received on the surface tb is exceeded, and the fixing ring 5 does not rotate around the pipe 12.
Therefore, when the cap 3 that presses and fastens the pipe 12 by reducing the diameter of the fixing ring 5 is finally screwed, the fixing ring 5 simply presses the pipe 12 against the inner core 9 without rotation, and the plastic resin pipe 12 Can be fastened with a pipe joint without causing buckling or twisting due to co-rotation.

If the cap 3 is manually tightened until it becomes hard, the diameter of the fixing ring 5 is reduced so that the diameter-reducing slit 5G bites into the plastic resin pipe outer peripheral surface 12c, thereby preventing the plastic resin pipe 12 from being pulled out. At the same time, the watertight press against the inner core 9 of the pipe 12 is ensured.
For this reason, the pipe joint of the present invention is a simple one-touch connection fastening operation, but the joint portion of the plastic resin pipe 12 does not cause a co-rotation phenomenon, and the O-ring 4 is displaced and damaged. Therefore, it is possible to perform reliable watertight pressing and reliable pipe fixing and holding.

Further, in the present invention, as shown in FIG. 1A, the inner core 9 includes a plurality of O-rings 4, and when the cap 3 is screwed and fastened, the tapered surface ta at the front portion of the fixing ring 5 It is preferable that the fixing ring 5 presses the plastic resin pipe 12 against the O-ring 4 by the cooperative action with the joint body tapered surface t8.
In this case, if a plurality of O-rings 4 are arranged at an appropriate interval, the inner peripheral surface 12d of the plastic resin pipe and the O-ring 4 group constitute a face seal, and the protruding dimension of each O-ring 4 is suppressed. However, typically, the O-ring 4 has a center interval (L9 ′) of 5 mm, and each O-ring 4 is arranged in a form protruding 0.5 mm from the inner core outer peripheral surface 9c. .

Further, the fixing ring 5 preferably has a dimension in which the front-rear width (axial width) W5 of the inner peripheral surface 5d covers from the arrangement area of each O-ring 4 to the tip area of the inner core 9, and typically the fixing ring 5 5, the width W5 is 19 mm, the width Wa of the front tapered surface ta is 7 mm, and the width Wb of the rear tapered surface tb is 4 mm.
In this case, since the fixing ring 5 is required to have a function of preventing the plastic resin pipe 12 from being pulled out (extracted), the inner peripheral surface 5d of the fixing ring 5 has, for example, friction such as an uneven surface and a screw surface. It is preferable to provide a force increasing means.

Accordingly, in the present invention, the fixing ring 5 is press-fitted into the conical taper surface t8 of the joint body 8 at the front portion with respect to the plastic resin pipe 12, and the inner peripheral surface 3d of the cap 3 is conical taper surface. The taper surface ta that receives the pressing force guaranteed by securing the outer periphery of t8 provides sealing action and fastening locking of the O-ring 4, and the taper surface tb is fastened by pressing the cap 3 at the rear. Since the locking action is imparted, the watertight pressing action and the pull-out prevention are ensured.
Since a plurality of O-rings 4 can form a sealing action surface, the O-ring 4 is arranged so that the O-ring 4 does not become an insertion-fitting trouble when the plastic resin pipe 12 is inserted into the inner core 9 by being covered. Even when the projection amount is small (standard: 0.5 mm), a complete watertight pressing action on the plastic resin pipe 12 by the fixing ring 5 can be obtained.
Therefore, it is easy to insert the plastic resin pipe 12 into the pipe joint, the connection can be fastened only by manually rotating the cap 3, and there is no fear of water leakage or pulling out. It becomes a pipe joint.

In the present invention, it is preferable that all members constituting the pipe joint are made of a plastic resin, and at least the inner core 9, the joint body 8, and the cap 3 are made of a transparent plastic resin.
In this case, being transparent means transparent or colored translucent, and means that the back side (inner side) component (member) can be seen through.
Further, since the O-ring 4 is a member on the inner side of the plastic resin pipe, if the O-ring 4 is black, it can be visually observed from the outside through the colored plastic resin pipe 12.

Accordingly, at the time of connecting the plastic resin pipe 12 by the pipe joint, whether the tip of the plastic resin pipe 12 is properly fitted to a predetermined position, whether each O-ring 4 is maintained in an appropriate state, or whether the fixing ring 5 is in an appropriate state , Etc. can be visually observed by an operator, and fastening work is facilitated.
The conventional water supply pipes and hot water supply pipes are the same color, the cross-linked polyethylene pipes are translucent and the polybutene pipes are cream-colored. High flexibility, ethylene. Octene. If a water / hot water supply pipe made of copolymer resin is adopted, the water supply pipe is white and the hot water supply pipe is pink.

Further, in the present invention, as shown in FIG. 6, the fixing ring 5 has an axial width (front-rear width) W5 having a dimension that covers the O-ring 4 region from the tip of the inner core 9 and has an inner circumference. The surface 5d is preferably provided with a plurality of circumferential grooves 5G '.
The O-rings 4 are typically arranged at two intervals of 5 mm, and the outer O-ring locking grooves 9G are arranged 12 mm from the tip of the inner core 9, so that the shaft of the fixed ring 5 is The direction dimension W5 may be about 20 mm (standard: 19 mm).
Further, the circumferential groove 5G ′ of the inner peripheral surface 5d only needs to have a function of holding and holding (preventing pull-out) with respect to the plastic resin pipe outer peripheral surface 12c, and the width, depth, and interval of the groove 5G ′ are as follows. It may be determined appropriately according to the target plastic resin pipe 12, but typically, as shown in FIG. 6 (B), two inner circumferential grooves having a depth of 0.3 mm and a width of 0.3 mm are provided on both sides. It is 3 mm inside from 5F and rear surface 5B.

Accordingly, if the fixing ring 5 is reduced in diameter with respect to the outer peripheral surface 12c of the plastic resin pipe 12 to generate a pressing action, the outer peripheral surface 12c of the plastic resin pipe 12 is microscopically compressed and deformed. As a result, the groove 5G ′ bites into the groove 5G ′ and the gripping force of the fixing ring 5 on the resin pipe 12 increases.
The plastic resin pipe 12 has the inner peripheral surface 12d pressed by the plurality of protruding O-rings 4 by the pressing action of the fixing ring 5, and the outer peripheral surface 12c bites into the plurality of grooves 5G 'and has a reduced diameter. Since the slit 5G also assists the locking action, the fixing ring 5 has a watertight sealing action and a pull-out prevention action on the plastic resin pipe 12 over a wide peripheral surface from the tip of the inner core 9 to the arrangement area of the O-ring 4. Is imparted by a surface action, and a strong watertight press and a strong locking and holding action are achieved.

In the present invention, as shown in FIG. 6, the fixing ring 5 is provided with a gently inclined taper surface ta on the outer periphery of the front part so as to be aligned with the tapered surface t8 of the joint body 8, and steeply inclined on the outer periphery of the rear part. The taper surface tb of the cap 3 is preferably aligned with the taper surface t3 of the cap 3, and the insertion hole H5 having the same diameter as the insertion hole H3 of the cap 3 is preferably provided.
In this case, typically, as shown in FIG. 6C, the fixing ring 5 has an axial length W5 of 19 mm, a tapered surface ta having a length Wa of 7 mm, and a tapered surface tb having a length Wb. 4 mm, the outer diameter R5 of the outer peripheral surface 5c of the cylindrical portion is 27.6 mm, an insertion hole having a diameter of 17.6 mm passes through the center portion, and the side surface has a small width for reducing diameter in the form of a split groove (standard) : 2.5mm) slit 5G, and the inner circumferential surface 5d has two circumferential grooves 5G 'each having a width of 0.3 mm and a depth of 0.3 mm, 3 mm inwardly from the front surface 5F and the rear surface 5B. It is arranged in.

Further, the front tapered surface ta (standard: 1/7 gradient, 7 mm length) of the fixing ring 5 is slower and longer than the rear tapered surface tb (standard: 1/4 gradient, 5 mm length).
Accordingly, as shown in the left half of FIG. 1A, in the state where the cap 3 is temporarily screwed to the joint body 8, the fixing ring 5 is in a state in which the posture is controlled by the tapered surface t3 at the rear portion of the cap 3. The insertion hole H5 of the fixing ring 5 occupies the alignment position with the insertion hole H3 of the cap 3, and if the plastic resin pipe 12 is inserted from the rear surface 3B of the cap 3, the insertion hole H5 having the same diameter smoothly penetrates. .
Therefore, the diameter of the insertion hole H5 of the fixing ring 5 can be set to the same diameter as the diameter of the insertion hole H3 of the cap 3, the fixing ring 5 has the minimum necessary diameter, and the plastic resin pipe 12 can be tightened. Can be achieved.

  The pressing and fastening action of the fixing ring 5 to the plastic resin pipe 12 advances the fixing ring 5 from the steeply inclined taper surface t3 of the cap 3 via the steeply inclined taper surface tb at the rear of the fixing ring 5, Since the front taper surface ta having a long and gentle inclination of the fixing ring 5 is inserted into the joint body 8 while gradually increasing the pressure contact force, and the front taper surface ta receives the early transmission of the frictional force, the fixing ring 5 At the stage of contacting the surface of the pipe 12 and receiving a frictional force from the outer peripheral surface 12c of the pipe 12, the fixing ring 5 no longer has only a pressing force action while the frictional force of the cap 3 against the tapered surface tb at the rear part causes a slip, Even at the time of strong forward tightening action by the rotation of the cap 3 thereafter, the joint of the taper surface ta of the front portion of the fixing ring 5 (standard: 7 mm) and gently inclined (1/7 gradient). Due to the strong frictional force with the main body taper surface t8 and the biting of the slit 5G and the groove 5G 'on the inner peripheral surface into the pipe outer peripheral surface 12c, the fixing ring 5 does not twist around the plastic resin pipe 12 and twists. The pipe 12 is firmly pressed and fastened.

  For the arrangement area of the O-ring 4 projecting from the outer peripheral surface 9c of the inner core, the proper pressure contact force, that is, the cap is obtained by the cooperative action of the long tapered surface ta of the fixing ring 5 and the joint body tapered surface t8. 3 until the manual rotation of 3 becomes hard, and the outermost periphery is secured by the cap 3, so the fixing ring 5 is in the O-ring 4 arrangement area where the maximum pressure contact force against the plastic resin pipe 12 is required. A positive and safe seal fastening to the pipe 12 is provided by a pressing action that gradually increases gradually and reaches a predetermined pressure.

Accordingly, the plastic resin pipe 12 has a pressure sealing action on the O-ring 4 by a unique and reliable pressing action by the front tapered surface ta and a secondary pressing action by the rear tapered surface tb in the fixed ring 5. And the sealing action by the press contact with the inner core outer peripheral surface 9c and the locking action for preventing the pull-out are received.
For this reason, the pipe joint of the present invention has a sealing action and a pull-out preventing action without inserting a predetermined plastic resin pipe 12 and manually rotating the cap 3 without giving a joint action to the connecting pipe 12. Therefore, it is possible to reliably achieve pull-out prevention connection with a leak-proof seal without damaging the plastic resin pipe 12 for connection.

In the present invention, as shown in FIG. 1, the inner core 9 and the joint body 8 are sockets having a symmetrical structure in the longitudinal direction. The cap 3 is fitted from both sides, and the plastic resin pipe 12 is attached from both sides. An insertion connection is preferred.
In this case, as shown in FIG. 1, the joint body 8 and the inner core 9 are prepared in a symmetrical form in the longitudinal direction, and the cap 3 including the fixing ring 5 fitted therein is fitted to both ends of the joint body 8 with a temporary fitting screw. If worn, the pipe joint can be inserted and connected to the plastic resin pipe 12 from both sides.
Therefore, the symmetrical double-headed socket-type pipe joint is effective as an elongated joint of the plastic resin pipe 12.

Further, according to the present invention, as shown in FIG. 7, the joint body 8 has an elbow shape, and a plastic resin pipe 12 can be connected and fastened to a pipe joint at one end. What provided the screw surface 10S is preferable.
In this case, the joint body 8 may be formed by integrally forming a pipe joint structure in one half and a bent elbow pipe 10 in the other half, and the inner core 9 has a joint body as shown in FIG. What is necessary is just to prepare for the dimension corresponding to this pipe joint structure.
Therefore, if the pipe joint of the present invention is adopted, the plastic resin pipe 12 can be connected to one end by a one-touch operation, and a water tap or socket (not shown) as a terminal device can be connected to the other end. It is effective for pipe construction that adopts.

  In the pipe joint of the present invention, the plastic resin pipe 12 is inserted into the gap dg between the joint body 8 and the inner core 9 along the outer periphery of the inner core 9 from the cap 3 fitted to the end of the joint body 8. 3 can be secured to the outer peripheral surface 9c of the inner core 9 by the fixing ring 5 in which the diameter of the plastic resin pipe 12 is reduced by simply screwing the joint 3 to the joint body 8 manually. And can be connected in a watertight manner without fear of pulling out.

  And even if the plastic resin pipe 12 is in a state with a curl hook, that is, in a state with a curved hook or an elliptical deformation hook, the insertion into the pipe joint is a covering fit into the inner core 9. The flexible pipe 12 is inserted while being corrected to have a perfect circular cross section, and passes smoothly over the O-ring 4 disposed on the outer peripheral surface 9c of the inner core 9, so that the O-ring 4 is removed or damaged. Since it does not receive, the press to the inner core 9 outer peripheral surface 9c of the plastic resin pipe 12 by the fixing ring 5 achieves a predetermined watertight press.

  Further, the rotational screwing forward action of the cap 3 to the joint body 8 is performed by connecting the fixing ring 5 having the taper surfaces ta and tb before and after the diameter reduction by the forward screwing of the cap 3 between the joint body 8 and the cap 3. By being interposed, the plastic resin pipe 12 can be firmly and watertightly attached to the outer peripheral surface 9c of the inner core 9 without twisting the plastic resin pipe 12 together, and the cap 3 is manually rotated. With a one-touch operation that only requires fastening with, reliable and complete watertight fastening is possible.

An embodiment will be described as a socket-type pipe joint 1 applied to a plastic resin pipe having a nominal diameter 13A of JIS standard, an outer diameter of 17 mm, and an inner diameter of 13 mm.
FIG. 1 (A) is a longitudinal sectional view of the socket-type pipe joint 1. In FIG. 1 (A), the right pipe joint is in a state where the pipe 12 is connected, and the left pipe joint is just before the pipe insertion. FIG. 1B is a side view of FIG. 1A.
As shown in FIG. 1A, the socket-type pipe joint 1 includes a joint body 8 in which a joint body 8 is screwed onto the outer periphery of an inner core 9 provided with a water passage hole H9 and a fixing ring 5 is fitted and enclosed. 8 is screwed onto the outer periphery of the end portion.

[Inner core 9 (FIG. 4)]
4A and 4B are explanatory views of the inner core 9, wherein FIG. 4A is a longitudinal side view, and FIG. 4B is a side view.
The inner core 9 is transparent, made of polyetherimide resin (trade name: Ultem resin), and is a pipe-shaped molded product having a general thickness of 3 mm. The total length L9 is 98 mm, and the inner diameter R9 ″ is the water passage hole H9. 6.7 mm, outer diameter R9 ′ is 12.6 mm, and the outer periphery of the central portion of the cylinder has a bulging thick portion with a diameter R9 of 20 mm, and the outer peripheral surface of the bulging thick portion has a length of 18 mm. And a step portion d9 having a height of 3.65 mm is provided from the inner core outer peripheral surface 9c to the bulging screw surface 9S.
Further, a taper surface t9 having a 1/3 gradient for facilitating insertion into the plastic resin pipe 12 is attached to the outer periphery of both ends, and an O-ring is provided at an intermediate position between the step portion d9 and the tip of the outer peripheral surface 9c. In this example, two locking grooves 9G having a width of 1.9 mm and a depth of 1.4 mm for inserting 4 are arranged with a distance L9 ′ of 5 mm.

[Fitting body 8 (Fig. 2)]
2A and 2B are explanatory views of the joint body, in which FIG. 2A is a longitudinal side view, FIG. 2B is an end view, and FIG. 2C is a side view.
Like the inner core 9, the joint body 8 is a pipe-shaped molded product made of polyetherimide resin (product surface: Ultem resin) with a general thickness of 4 mm. Caps 3 are provided on both sides of the outer peripheral surface 8c. A screw thread 8S is arranged in a form in which a thread thread protrudes from the outer peripheral surface 8c, and a metric fine screw (JISB0207) with a short screw interval for screwing so as not to loosen, and at the center of the outer peripheral surface 8c. When the inner core is attached, a flat surface 8f for contacting a jig (wrench or the like) that prevents the joint body 8 from rotating is arranged symmetrically on the front and back, and the inner peripheral surface 8d A threaded surface 8S ′ for screwing the core 9 is arranged in a protruding form from the inner peripheral surface 8d.

Further, at both ends of the inner peripheral surface, a fitting hole H8 ′ having a length L8 ′ with which the fixing ring 5 is fitted is 7 mm is arranged in an outwardly expanded form through a stopper surface st having a stopper function, The inner peripheral surface that expands outward from the fitting hole H8 ′ is defined as a tapered surface t8.
The tapered surface t8 was formed with a length L8 ′ of 7 mm, an inner end diameter of 21.6 mm, and an outer end diameter of 22.4 mm.
The dimensional relationship of the joint body 8 is that the outer diameter R8 is 26.4 mm, the total length L8 is 73 mm, the center is provided with an insertion hole H8 with a diameter R8 ′ of 19.6 mm, and the length of the inner peripheral surface 8d. In the center portion, a screw surface 8S ′ for inner core screwing is arranged in a projecting form from the inner peripheral surface 8d over a length of 18 mm, and the screw surfaces 8S on both sides of the outer peripheral surface have a length (L8 ′) from the tip. ) 7 mm was placed and placed in a range of 12 mm in length.

[Cap 3 (Fig. 3)]
3A is a rear view of the cap 3, and FIG. 3B is a longitudinal side view.
The cap 3 is a transparent polyphenylene oxide resin (trade name: Noryl resin) molded product, and has a pipe shape as shown in FIG. 3A. The outer peripheral surface 3c has an anti-slip for manual rotation. The longitudinal projections 3P are arranged in a hexagonal shape, and the rear surface 3B is provided with a circular insertion hole H3 having a diameter R3 ″ of 28 mm for inserting the plastic resin pipe 12, slightly more than the front surface 3F (standard) 1 mm) A metric fine screw 3S (JISB0207) for screwing the joint body 8 is provided on the inner peripheral surface 3d from the inside to the front and rear 12mm, and the taper surface tb of the fixing ring 5 is abutted on the inner side of the rear surface 3B. The taper surface t3 is provided.

  The pipe-shaped cap 3 has a general thickness of 3.5 mm, a length L3 of 38 mm, and a diameter R3 of the cylindrical outer peripheral surface 3c of 35 mm. The outer peripheral surface 3c has a width of 5 mm and a protruding height d3 of 1. 5 mm lengthwise projections 3P are provided in a hexagonal shape at equal intervals, the diameter R3 ′ of the insertion hole H3 in the center of the rear surface 3B is 17.6 mm, and the thread surface 3S in the front part of the inner peripheral surface 3d has a width of 12 mm. This is a metric fine thread surface with a pitch interval of 1.5 mm and a height of 0.8 mm. The tapered surface t3 on the rear surface of the inner peripheral surface is a 1/4 gradient from the inner peripheral diameter (R3 ″) of 28 mm, and the rear is 8 mm in length. It is a truncated conical surface that is reduced in diameter.

[O-ring 4 (Fig. 5)]
5A is a front view of the O-ring, and FIG. 5B is a vertical side view of the O-ring.
The O-ring 4 is a sealing member that is fitted in and attached to the locking groove 9G having a width of 1.9 mm and a depth of 1.4 mm of the inner core 9, and is a thick nitrile rubber (JISB2401) that has excellent wear resistance and heat resistance. This is a circular ring with a cross-section having a width W4 of 1.9 mm and an inner diameter R4 of 9.8 mm, and is colored black (colored with a stock solution).

[Fixing ring 5 (FIG. 6)]
6A and 6B are explanatory views of the fixing ring 5, in which FIG. 6A is a side view, FIG. 6B is a rear view, and FIG. 6C is a longitudinal sectional view.
The fixing ring 5 is a molded product made of polyphenylene oxide resin (trade name: Noryl resin), and the overall shape is a diameter for inserting the plastic resin pipe 12 at the center as shown in FIG. R5 ′ has an insertion hole H5 of 17.6 mm, a front-rear width W5 of 19 mm, and a conical taper surface ta that expands from the front surface 5F to the central portion on the outer peripheral surface 5c, and a tapered surface t8 of the joint body 8 The length Wa is 7 mm, and the conical tapered surface tb whose diameter is expanded from the rear surface 5B to the tapered surface t3 on the inner periphery of the rear surface of the cap 3 is aligned with the length Wb. Has 4mm.

  Then, a slit (5G) having a small width (standard: 2.5 mm) in order to reduce the diameter when external pressure is applied to the fixing ring 5 is provided in a split groove shape over the entire length as shown in FIG. 6 (A). If the outer peripheral surface 12c of the plastic resin pipe 12 is reduced in diameter and pressed on the inner peripheral surface 5d, two small grooves (in the circumferential direction) for the plastic resin pipe outer peripheral surface 12c to bite in due to elastic deformation ( Standard: depth 0.3 mm, width 0.3 mm) are arranged at positions of 3 mm from the front surface 5F and 3 mm from the rear surface 5B of the inner peripheral surface 5d.

(Use of pipe fittings)
In the factory, as shown in the left half of FIG. 1 (A), the pipe joint is provided with each locking groove 9G (inside the inner core 9 in a cylindrical portion having an outer diameter R9 ′ of the cylindrical outer peripheral surface 9c of 12.6 mm). A black O-ring 4 (diameter 1.9 mm, inner diameter 9.8 mm) is fitted to a width 1.9 mm and a depth 1.4 mm, and then a screw at the center of the inner peripheral surface 8d of the socket joint body 8 The threaded surface 9S at the center of the outer peripheral surface of the inner core 9 for socket is screwed into the surface 8S ', and the pipe 12 is inserted between the outer peripheral surface 9c of the inner core 9 and the inner peripheral surface 8d of the joint body cylindrical portion. A gap dg is formed and tightened.
In this case, workability is good because the inner core 9 is screwed and fastened by sandwiching and holding the flat surfaces 8f on both sides arranged at the center of the joint body outer peripheral surface 8c.

Next, as shown in the left half of FIG. 1A, the fixing ring 5 is inserted into the cap 3 such that the rear tapered surface tb is on the side of the tapered surface t3 of the cap 3, and the front tapered surface ta is on the joint body 8. The cap 3 is temporarily screwed onto the end of the joint body 8 with the taper surface t8 side in place.
In this case, the fixing ring 5 is in a loosely-fitted free state in the cap 3, and the rear surface 5B is in contact with and supported by the tapered surface t3 of the cap 3, so that the insertion hole H3 on the rear surface of the cap 3 is provided. And the insertion hole H5 of the fixing ring 5 have the same diameter and a front-rear alignment form.
Then, in a state where the cap 3 is temporarily screwed into the joint body 8, the pipe body is carried into the construction site as a pipe joint.

At the construction site, as shown on the left side of FIG. 1 (A), as a plastic resin pipe 12, ethylene. With a nominal diameter 13A (outside diameter R12: 17 mm, inside diameter R12 ′: 13 mm) of JIS standard is used. Octene. The tip of the copolymer (PE-RT) resin pipe 12 passes through the fixing ring 5 (hole diameter: 17.6 mm) from the insertion hole H3 (hole diameter: 17.6 mm) of the rear end (rear surface 3B) of the cap 3, The inner periphery of the inner core 9 is fitted in a cover form, and the gap dg is inserted up to the step portion d9.
In this case, since the cap 3, the joint body 8, and the inner core 9 are transparent, the state in which the plastic resin pipe 12 is not displaced in the O-ring 4 and the end of the pipe up to the step d9 at the innermost part are appropriate. It can be carried out by visually confirming the state of being inserted into the.

Next, the cap 3 is rotated by hand, and is screwed forward to the joint body 8 until it feels firm.
As the cap 3 rotates forward with respect to the joint body 8, the fixing ring 5 included in the cap 3 is also pushed forward by the taper surface t <b> 3 inside the rear portion of the cap 3, and loosens around the outer periphery of the plastic resin pipe 12. The fixing ring 5 that has been fitted has a precise, press-fitting action in which the gently sloping and long tapered surface ta on the front side gradually increases into the conical surface of the tapered surface t8 of the joint body. The short taper surface tb is subjected to the crown pressing action of the taper surface t3 of the rear portion of the cap 3 which is rapidly increased, and the diameter of the plastic resin pipe 12 is reduced over the entire length by receiving the pressing action of the front portion and the rear portion. The outer peripheral surface 12c is pressed.

In this case, in the state in which the cap 3 is fully tightened, as shown on the right side of FIG. 1 (A), the fixing ring 5 presses the outer peripheral surface of the O-ring 4 in the first half portion, and the plastic resin pipe 12 The inner peripheral surface 12d and the outer peripheral surface 9c of the inner core 9 are completely watertight pressed, and the latter half part achieves watertight pressing of the inner peripheral surface 12d of the plastic resin pipe to the outer peripheral surface 9c of the inner core 9, Two small grooves 5G ′ in the circumferential direction of the inner peripheral surface 5d of the fixing ring 5 and one slit 5G in the form of a split groove have a biting action on the outer peripheral surface 12c of the flexible plastic resin pipe 12. This also prevents the plastic resin pipe 12 from being pulled out from the pipe joint.
That is, in the socket type pipe joint shown in FIG. 1, the pipe 12 can be connected by one-touch by simply inserting the pipe 12 from both sides and rotationally tightening the cap 3, guaranteeing watertight pressing and pull-out prevention retention. A possible pipe connection can be achieved.

[Modification (FIG. 7)]
FIGS. 7A and 7B are explanatory views in which the pipe joint of the present invention can be applied to connection of a faucet or the like in the form of an elbow, and FIG. 7A is a longitudinal side view and FIG. 7B is a side view.
In this case, as shown in FIG. 7A, the other end of the joint body 8 is a bent elbow pipe 10, and the inner core 9, the joint body 8, and the cap 3 are disposed only on one end side of the joint body 8. That is, the socket type pipe joint 1 shown in FIG. 1 is configured to correspond to one end side, and the connecting thread surface 10S is arranged on the inner periphery of the tip of the elbow pipe 10 at the other end according to the fitting to be screwed.
Therefore, the pipe joint 2 is fixed at a predetermined position at the time of piping construction, the plastic resin pipe 12 is connected to the joint body 8 at one end by a one-touch operation, and a water tap or a water supply side socket not shown is connected to the other end. Metal fittings can be screwed and fixed.

It is explanatory drawing of the socket type pipe joint of this invention, Comprising: (A) is a vertical side view, (B) is a side view. It is explanatory drawing of the coupling main body 8, Comprising: (A) is a vertical side view, (B) is an end view, (C) is a side view. It is explanatory drawing of the cap 3, Comprising: (A) is a rear view, (B) is a vertical side view. It is explanatory drawing of the inner core 9, Comprising: (A) is a vertical side view, (B) is a side view. It is explanatory drawing of the O-ring 4, Comprising: (A) is a front view, (B) is a vertical side view. It is explanatory drawing of the fixing ring 5, Comprising: (A) is a side view, (B) is a rear view, (C) is a longitudinal cross-sectional view. It is explanatory drawing which applied this invention to the elbow type pipe joint, Comprising: (A) is a vertical side view, (B) is a side view. It is explanatory drawing of the prior art example 1, Comprising: (A) is a vertical side view of the state before a connection, (B) is a vertical side view of a connection state. It is explanatory drawing of the prior art example 2, Comprising: (A) is a vertical side view of a connection state, (B) is the elements on larger scale of (A).

Explanation of symbols

1 Socket type pipe fittings (pipe fittings)
2 Elbow type pipe fitting (pipe fitting)
3 Cap 3B, 5B Rear surface 3c, 5c, 8c, 9c, 12c Outer peripheral surface 3d, 5d, 8d, 9d, 12d Inner peripheral surface 3F, 5F Front surface 3P Projection 3S, 8S, 8S ', 9S, 10S Screw surface 4 O-ring 5 fixing ring 5G slit 5G 'groove 8 joint body 8f flat surface 9 inner core 9G locking groove 10 elbow pipe 12 plastic resin pipe (pipe)
dg Clearance d9 Step H3, H5, H8 Insertion hole H8 'Fitting hole H9 Water passage holes t3, t5, t8, t9 Tapered surface st Stopper surface

Claims (7)

  The joint body (8) is mounted on the outer periphery of the tubular inner core (9), the cap (3) is attached to the end of the joint body (8), and the plastic resin pipe (12) is passed through the cap (3). A pipe joint that is inserted into the inner core (9) and is connected to the plastic resin pipe (12) by one-touch rotation of the cap (3). The inner core (9) has a water passage hole (H9). The outer peripheral surface (9c) is provided with a thread surface (9S) for screwing the joint body (8) and an O-ring (4) fitted in the locking groove (9G). The joint body (8) is in the form of a pipe, the inner peripheral surface (8d) has a thread surface (8S ') for screwing the inner core (9), and the outer peripheral surface (8c) has a cap (3 ) A threaded thread surface (8S) is provided, and the inner peripheral surface end portion is a tape that expands outward. The cap (3) has an insertion hole (H3) on the rear surface (3B), and a threaded surface (3S) that engages with the threaded surface (8S) of the joint body on the front surface of the inner peripheral surface. ) At the rear part of the inner peripheral surface, and has a tapered surface (ta) that aligns with the tapered surface (t8) of the joint body at the front part, and a cap at the rear part. A taper surface (tb) aligned with the taper surface (t3) of (3) is provided on the outer periphery, and a fixing ring (5) provided with a slit (5G) for diameter reduction is fitted and contained, and a plastic resin pipe ( 12) is inserted into the gap (dg) between the inner core (9) and the joint body (8) from the insertion hole (H3) of the cap (3), and the fixing ring is screwed into the cap (3). (5) The diameter is reduced, and the plastic resin pipe (12) is connected to the inner core (9) outer peripheral surface (9 Pipe joints for plastic resin pipes that are watertight pressed against c).   The inner core (9) includes a plurality of O-rings (4), and when the cap (3) is screwed and fastened, a taper surface (ta) of the front portion of the fixing ring (5) and a tapered surface of the joint body (t8) The fitting according to claim 1, wherein the fixing ring (5) presses the plastic resin pipe (12) against the O-ring (4) by the cooperative action.   The pipe joint according to claim 1 or 2, wherein all members constituting the pipe joint are made of plastic resin, and at least the inner core (9), the joint body (8), and the cap (3) are made of transparent plastic resin. .   The fixing ring (5) has an axial width (W5) that covers the O-ring (4) region from the tip of the inner core (9), and a plurality of circumferential directions on the inner peripheral surface (5d). The pipe joint according to any one of claims 1 to 3, comprising a groove (5G ').   The fixing ring (5) has a tapered surface (ta) that is gently inclined on the outer periphery of the front part in a form that is aligned with the tapered surface (t8) of the joint body (8), and a tapered surface (tb) that is steeply inclined on the outer periphery of the rear part. And an insertion hole (H5) having the same diameter as the insertion hole (H3) of the cap (3). The pipe joint of any one of thru | or 4.   The inner core (9) and the joint body (8) are in the form of a symmetrical socket in the longitudinal direction, and the cap (3) is fitted from both sides, and the plastic resin pipe (12) is inserted and connected from both sides. The pipe joint according to any one of claims 1 to 5.   The joint body (8) is in an elbow form, and a plastic resin pipe (12) can be connected and fastened to a pipe joint at one end, and a connecting thread surface (10S) is provided on the other end inner surface of the elbow pipe (10). The pipe joint according to any one of claims 1 to 5, which is provided.

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