JPS5843249B2 - If you want to use the pipe ring, please contact us. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming pipes having a ring embedded in the inner circumferential wall thereof, and more specifically, a method of forming a ring on the inner circumferential wall of the end of a thermoplastic resin pipe. The present invention relates to a method of forming pipes having a ring having a diameter.

Pipes in the present invention collectively refer to long pipes with a socket on one side and an inlet on the other, or collar joints, etc.
The present invention relates to a molding method for an improved structure of the socket portion of the long pipe and the portion to which a backing such as a sealing rubber ring is attached to the collar joint.

Various methods for joining pipes have been researched in the past, and even in the case of a so-called single-receiver and single-push pipe, in which one end of a long pipe is expanded in diameter and used as a socket, and the other end is used as a socket. After forming the socket part, an enlarged part is further provided in a part of the enlarged diameter part, and a backing, such as a rubber ring for sealing, is attached to the groove on the inner peripheral surface corresponding to the enlarged part, thereby making it watertight. There is a known method to prevent the pipe from separating due to the frictional force of the backing.

In addition, in the case of a collar joint known as a so-called flexible joint, a ridge is provided on the outer periphery of the tube end, and by attaching a backing to the groove on the inner circumferential surface corresponding to the ridge, it is possible to achieve the same purpose. has been achieved.

By the way, in these methods, when joining pipes, a backing is installed in the internal groove in advance, and then the pipes are inserted and joined.

However, since the backing may start to roll due to the frictional force during insertion, there is a risk that safe and reliable joining may be inhibited, and it is still difficult to say that this is sufficient.

In addition, these enlarged parts are usually formed by post-forming on pipes that have already been extruded. The thickness tends to be thinner than the non-expanded portion.

Therefore, the enlarged portion is susceptible to stress concentration, and not only the strength of the pipes tends to decrease, but also the rigidity of the enlarged portion tends to decrease.

Furthermore, when molding is performed by injection molding, similar difficulties are observed, so solving these problems has become an important issue.

The present inventors have focused on improving the above-mentioned drawbacks and have completed the present invention as a result of various efforts.

That is, an object of the present invention is to prevent as much as possible the backing from rolling out of its predetermined position during insertion and joining of pipes, and to suppress as much as possible the tendency for strength and rigidity to decrease in the enlarged portion. Another object of the present invention is to provide a method by which pipes with increased strength and rigidity can be easily and reliably formed.

Accordingly, the method of the present invention includes coating a deformable core holding a ring with a thermoplastic or thermoplastic resin material;
This is done by deforming and removing the core after the resin has hardened.

The method of the present invention can be applied to either an injection molding method or a post-molding method for pipes that are once formed by extrusion molding.

That is, in the case of injection molding, for example, resin is injected with a mold containing the core placed in the resin injection hole of an injection molding machine, and after the resin is cooled and hardened, the core is Only the core is removed while deforming and leaving the ring implanted in the inner wall of the pipe, and this method is applicable to both thermoplastic and thermoplastic resins.

In the case of the post-molding method, the ends of the extruded pipes are heated and softened, and the core is inserted into the pipes.

After the pipes are cooled and hardened, the core is deformed and only the core is removed while leaving the ring embedded in the inner wall of the pipe, and this method can be applied to thermoplastic wood.

It should be noted that the shape of the core can be changed in various designs, and differences in details due to differences in the method should naturally be tolerated, even in the case of injection molding and post-molding. Also, in the case of injection molding itself, the optimum one should be selected depending on the molding machine.

Of course, it goes without saying that the design can be changed depending on the type of pipe to be molded (long pipe, collar joint, etc.), diameter, length, wall thickness, material, etc.

The present invention has wide applicability as described above, but for convenience of explanation, the following description will focus on a method of implanting a ring into a thermoplastic resin pipe according to a post-molding method. The technical scope is not limited to the explanation below.

A more specific and illustrative method for implanting a ring having an outer diameter larger than the inner diameter of the thermoplastic resin pipe on the inner circumferential wall of the end of the thermoplastic resin pipe will be described, for example, as follows. It is carried out as follows.

Namely, ■ a step of latching the ring onto a deformable core; ■ a step of fixing the ring by deforming the core;
The process of inserting the core into the heat-softened thermoplastic resin tube at the end of the tube; ■The process of compressing and shaping the inside of the tube, which is raised by expanding the ring, from the outer circumferential direction; ■The process of deforming the core and inserting the ring into the inner circumferential wall of the resin tube The process of removing only the core while it remains implanted can be carried out in an appropriate combination.

Therefore, when applying the above method to a pipe with a single support and a single push, the diameter of the core is changed stepwise, a relatively large ring is used, and the end of the thermoplastic resin pipe is , which is carried out by heating and softening over a relatively wide area,
When adapting to collar joints, the diameter of the core does not change, and the outer diameter of the ring only needs to be made slightly larger than the inner diameter of the collar joint, and the softening of the collar joint is limited to the vicinity of the ring implantation area. There is no problem.

Further, the above steps of the present invention are not necessarily required to be performed in the order of ■ to ■, and for example, the steps of ■ and ■ may be performed in reverse, or the steps of ■ and ■ may be performed simultaneously. Alternatively, if possible, step (2) may be omitted; in any case, the object of the present invention is fully achieved and does not depart from the technical scope of the present invention.

The material of the ring used in the present invention is not particularly limited, and examples thereof include metals such as steel and alloys, thermosetting resins, and the like.

Further, although only one ring may be provided at the end of the tube, it is also possible to provide two or more rings if desired.

In addition, since the ring is used by engaging a backing such as a sealing rubber ring when joining the pipes after being implanted at the end of the pipe, the size and shape of the ring may vary depending on the size and shape. Any material may be used as long as it does not adversely affect the retention of the backing, the insertion and joining of the pipes, and the reinforcement of the pipes.

For example, the cross-sectional shape of the ring may be rectangular, circular, semicircular, oval, etc., and a hollow ring may also be used.

The core of the present invention is latched onto these rings and fixed by deforming the core.

Therefore, the core used in the present invention is capable of deforming itself, but it may have any structure as long as it can fix the ring to which it is simply latched by the deformation. However, it is possible to hire.

To give a typical example of such a structure, for example, when a segment with or without four-wheel grooves on its outer surface is in a contracted state, a ring is hooked to the four-wheel grooves or the outer peripheral surface of the segment, and the segment is A structure in which the ring, which is latched to the four-wheel groove or the outer peripheral surface of the segment, is pressed and fixed from the inner periphery of the ring by enlarging the segment; Examples include a structure in which the ring is clamped and fixed by deforming each segment (moving in the axial direction or expanding in the circumferential direction).

Therefore, the deformable core in the present invention is not limited to one that deforms over its entire structure, but also means one that deforms only partially, but in any case does not participate in the fixing operation of the ring. Any use of a core having a structure that allows the ring to be fixed by deformation is within the technical scope of the present invention, regardless of the deformability of the parts, such as the enlarged diameter part of a long tube.

As is clear from the above description, the core used in the present invention has a movable segment, and the movable segment can move back and forth in the axial direction, and can expand and contract in the circumferential direction. Examples include things.

A movable segment that can move back and forth in the axial direction is, for example, a short tubular ring that is closely attached to the outer periphery of the core, but in short, the movable segment moves and comes into contact with the end surface of the ring, fixing the ring. Any mechanism that can be used can be adopted.

Also, a movable segment that can be expanded or contracted in the circumferential direction is
For example, fan-shaped components are connected to form a circular shape, and when expanding, each component separates and deforms while expanding the diameter of the circular shape, or each component meshes like gears, and one side is They are arranged alternately in a fan-shaped cross section perpendicular to the axis of the core, one being reduced in the direction of the center and the other not being reduced, and each constituent member separates when expanded.
An example is a mechanism that expands the diameter of a circle composed of a sector-shaped outer circle, and in short, it is a mechanism that can firmly press and fix the inner surface of a ring having a constant inner diameter by expanding a movable segment, or a mechanism that can firmly press and fix the inner surface of a ring having a constant inner diameter, or a mechanism that can press and fix the inner surface of a ring with a fixed inner diameter by expanding a movable segment. Any mechanism that can secure the ring can be used.

The four-ring groove provided on the outer surface of the movable segment that allows expansion and contraction in the circumferential direction is particularly useful when pressing and fixing the inner surface of the ring. However, it is sufficient to provide the movable segments not necessarily around the entire circumference, but at appropriate positions at appropriate intervals, and the outer circumferential surface of the movable segment itself should be a smooth surface, and the movable segment at both ends of the movable segment in the axial direction of the core should be It may also be possible to form a four-wheel groove in combination with a vertical surface of the member or other movable segment that allows axial movement.

However, the fixation of the ring is not limited to fixation by pressing force from three directions on both end faces and the inner surface of the ring, but clamping fixation only from both end faces or suppressing fixation only from the inner face is sufficient. The object of the invention can be achieved.

The softened thermoplastic resin pipe slides on the ring and core fixed in this way, and the ring is implanted on the inner peripheral wall of the resin pipe, and a small bulge is formed on the outer peripheral wall of the corresponding part of the resin pipe. It is formed.

On the other hand, the tip of the tube that has advanced over the ring has a low height, so it naturally shrinks and comes into contact with the core.
Molded to desired inner diameter.

At this time, the present invention may further include a step of externally compressing and shaping the portion that is raised by expanding the ring.

According to this process, the diameter of the pipe tip can be reduced by an external force, the pipe portion that has stopped before the protruding portion is pressed in the direction of the ring, and the excessively protruding portion is corrected by pressing the ring. As a result, the gap between the ring and the pipe portion on the inner wall side is narrowed, resulting in an even tighter fit, and in some cases, the effect of compressing the pipe flesh on both sides of the ridge and the compression effect within the ridge may cause the portion in question to tighten. It is expected that this will help prevent and reshape the tendency towards thinner walls.

Once the ring has been installed, the core can be deformed to move or reduce the movable segment, and the ring and core can be separated from each other. When the pipes are removed, the ring can be installed on the inner wall. Pipes with the desired shape can be obtained as they are left in place, and by repeating the same steps, □ continuous molding is performed.

The method of the present invention is carried out as described above, but for better understanding, the method will be described below with reference to the drawings which are examples.

FIG. 1 is a partial sectional view of a pipe obtained by the present invention in a state in which a rubber ring is engaged with the pipe, and particularly shows the case of a single-receiver and single-push pipe.

In the figure, 1 is a pipe main body, 2 is a first stage enlarged part, 3 is a second stage enlarged part, 4 is a small raised part, 5 is a ring, and 6 is a rubber ring.

2 to 6 are schematic diagrams of each process of the present invention, and FIGS. 7 and 8 are sectional views of the movable segment.

9 to 13 are process diagrams showing examples of other methods.

Figure 2 shows core 7 before deformation. FIG. 2 is a schematic cross-sectional view of an IJ song and a prepared pipe 1 in an undeformed state.

In the figure, 8 is a movable segment before expansion.

9 is a thrust ring, 10 is a snap ring, 11 and 12 are shaping molds, and 13 is a movable segment recess.

Incidentally, the cross section taken along the line A-A in this state is as shown in FIG.

FIG. 3 is a schematic cross-section of a state in which the ring 5 is releasably latched to the movable segment recess 13 and is opposed to the pipe 1.

It will be appreciated that the upper end of the ring 5 is latched within the movable segment recess 13 and the lower end is free.

In FIG. 4, the thrust ring 9 is slid to the right in the drawing, the movable segment 8 slides and expands on the contact surface, and the entire circumference of the ring 5 from the upper end to the lower end is pressed and fixed by the segment recess 13. It is a schematic sectional view of a state made to face a pipe 1.

The thrust ring 9 can be slid by a piston mechanism (not shown).

The snap ring 10 is formed of, for example, a circular spring and is expandable and contractible, and does not adversely affect the expansion and deformation of the segment 8.

Incidentally, a sectional view taken along line B-B in this state is as shown in FIG.

FIG. 5 shows the heated and softened pipe 1 sliding on the core deformed in this way.
is deformed into a first enlarged part 2, a second enlarged part 3, and a small raised part 4, and a ring 5 is brought into contact with the inner peripheral surface corresponding to the small raised part 4 to raise the tube wall.

After this, or at the same time, as shown in FIG.
1 and 12 (preferably divided into two or four parts) are moved in the direction of the small protuberance 4, press the pipe 1 and adjust the external shape, and at the same time complete the implantation of the ring 5. This reduces the gap between the small protrusions 4 and suppresses the tendency for the thickness of the small protuberances 4 to decrease.

In addition, the order of movement of the plastic outer molds 11 and 12 may be changed, for example, first the plastic outer mold 12 is moved to the left and the small raised portion 4 is moved.
, then move the outer mold 11 to the right, move the outer mold 12 to the right, and finally move the outer mold 11 to the right.
to the left, or slide the pipe 1 with the outer mold 11 moved to the right in advance, and at the same time move the outer mold 12 to the left so as to make it parallel to the pipe 1.
Finally, it is also possible to adopt a method in which the outer shaping mold 11 is moved to the left and the shaping die 12 is moved to the right.

Once the ring 5 has been installed in this way, the pipe 1 is sufficiently cooled and the shaping molds 11 and 12 are returned to their original positions.

Next, when the thrust ring 9 is moved to the left, the movable segment 8 is reduced and restored by the restoring force of the elastic snap ring 10, so that the core T can be easily removed from the pipe 1.

9 to 13 are schematic diagrams showing steps according to other embodiments.

Figure 9 shows a process corresponding to Figure 2, in which the core γ before deformation
, the ring 5 and the pipe 1 are shown in a prepared state.

In the figure, 8a is a movable segment that is allowed to move in the axial direction;
8b is a movable segment that is allowed to expand and contract in the circumferential direction, 9 is a thrust ring, and 10 is a snap ring.

FIG. 10 shows a process corresponding to FIG. 3, in which a ring 5 is latched onto the core 1.

The inner surface of the ring 5 is almost in close contact with the outer surface of the core 1, but it can slide on the core and is in an unfixed state.

FIG. 11 shows a process corresponding to FIG. 4, in which the ring 5 is fixed by external forces from three directions by sliding the movable segment 8a to the right and expanding the movable segment 8b.

The movable segment 8a is a short tubular ring, and the movable segment 8b can be expanded by movement of the thrust ring 9, since the same mechanism as the movable segment 8 in the previous embodiment can be adopted.

In this step, the movable segments 8a and 8b may be moved or expanded simultaneously or in stages, but in some cases, when the ring 5 is latched, the movable segments 1
-8a may be moved to the right.

Note that in this figure, the outer mold 14 is close to each other, but
The outer mold 14 corresponds to the outer molds 11 and 12 in the embodiment described above, and is used for compressing and shaping the small raised portion 4.

The outer mold 14 is preferably constructed in two to four parts.

FIG. 12 corresponds to FIG. 5, and shows a state in which the heated and softened pipe 1 is sliding on the deformed core.

The pipe 1 is transformed into a first enlarged part 2, a second enlarged part 3, and a small raised part 4, and a ring 5 is embedded in the inner surface corresponding to the small raised part 4.

After this, or at the same time, Figure 13 (corresponding to Figure 6)
As shown in FIG. 2, the outer cutting die 14 is pressed toward the core, adjusting the outer shape of the small raised portion 4 of the pipe 1, and completing the implantation of the ring 5.

Once the ring 5 has been installed in this manner, the pipe 1 is sufficiently cooled and the outer mold 14 is removed.

Next, when the thrust ring 9 is moved to the left, the movable segment 8b is reduced and restored due to the restoring force of the snap ring 10, so the movable segment 8a is either moved to the left or left as it is without being moved. The core 7 can be easily removed from the pipe 1 even if left as is.

Although the above embodiment shows the forming of the socket part of a single-sided and single-pressed pipe, the ring can be implanted by the same means when applied to a collar joint.

Further, the above-mentioned embodiment merely illustrates one embodiment, and it goes without saying that various other embodiments may be modified, improved, and designed.

Since the present invention is constructed as described above, detachment of the backing is prevented even by frictional force during insertion and joining, water pressure during use, etc., and the pipe end has increased strength and rigidity. Pipes with rings attached to the inner circumferential wall can now be formed extremely easily and reliably, and have extremely high industrial utility value.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a partial cross-sectional view of a molded pipe in a state of use, and FIG.
Figure 6 is a schematic sectional view showing the process of the present invention, Figures 7 and 8 are A
9 to 13 are schematic cross-sectional views of steps according to other embodiments. 1...Pipe, 4...Small raised part, 5.
...Ring, 6...Rubber ring, 7...
... Core, 8, 8a, 8b "°°°°° Movable segment, 9... Thrust ring, 10...
・Snap ring, 11, 12... Orthopedic mold,
13... Segment recess, 14... Outer cutting mold.

Claims (1)

[Claims] 1 A method of implanting a packing engagement ring made of a hard material on the inner circumferential wall of a socket of a pipe made of a thermoplastic or thermoplastic resin material, the ring being placed on the outer periphery of a deformable core. The entire circumference of the core and the outer circumference of the protruding part of the ring are coated with a thermoplastic or thermosetting resin material, and after the resin material has hardened, the ring is held by the core. A method of forming pipes with a ring embedded in the inner peripheral wall, which is characterized by releasing the core and removing the core.