JPS6045053B2 - Method for molding sockets for synthetic resin pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When synthetic resin pipes are connected to each other, one pipe end is enlarged to form a socket, and the other pipe end is inserted into this socket. Regarding the socket forming method for pipe joints,
In particular, this socket part is equipped with a filling ring that comes into contact with the tip surface of the recessed tube to regulate the recessed length, and also fills the stepped space between the tip of the repressed tube and the molded part of the socket. This article relates to a method for forming sockets that are installed in deep areas.

Conventionally, when synthetic resin pipes are used for piping, they are used as socket pipes with enlarged sockets formed at the ends of the pipes, or simply as joint members for pipe joining, with enlarged sockets formed at one or both ends of short pipes. It is well known to do so.

In addition, these enlarged sockets can be joined by simply press-fitting a recessed tube, or by using adhesive, or by using packing, but in any case, the repression tube cannot be inserted. The holding tube is generally inserted under pressure, except for special joints. In addition, these diameter expansion moldings are generally performed by heating the end of the resin tube to a degree that softens it and inserting it into a core mold, or by press-fitting a core mold into the softened tube end, but in both cases, the tip of the core mold The portion forms a diameter expansion guide slope. Therefore, the deep part of the socket forms an inclined surface. On the other hand, the distal end surface of a restraining tube is generally formed in a plane perpendicular to the tube axis, but this is often inaccurate. Therefore, when such a restraining tube is press-fitted into the socket, the tip thereof may come into contact with the inclined surface of the socket and be distorted in the direction of diameter reduction, or the end face may be damaged. Therefore, it is desirable to provide a stopper in the socket portion to restrict the insertion length of the holding tube. Further, as described above, the distal end surface of the holding tube is a surface perpendicular to the tube axis, while the contact surface of the socket portion is an inclined surface, so naturally a space is formed. However, this space provides resistance to the conveyed fluid and creates turbulent flow, causing fluid resistance and water hammer. Especially in the case of sewage pipes, solid matter mixed in the sewage accumulates in this space. It can also become stuck and obstruct the flow of sewage. Therefore, it is necessary to take measures to fill the joint space of such a socket with some kind of article. As a countermeasure against these problems, an attempt was made to cut the tip of the holding pipe to a slope that matched the slope of the inner part of the socket and join it, but although the space could be filled, the distortion caused by press fitting could not be avoided. Inevitably, it became necessary to take measures to protect the ends of the containment tubes from becoming sharp. For these reasons, it has been proposed to provide a filling ring at the rear end of the socket to restrict the insertion tube and fill the space. Such a filling ring is formed by cutting a resin pipe, or by injection molding from the same or different resin material as the pipe material.
In any case, the obtained filled ring is a thin ring and is easily deformed and distorted. In addition, such a filling ring may be placed on the inclined surface of the socket using adhesive after forming the socket, but as mentioned above, it is a thin ring and is easily deformed and distorted. It is difficult to arrange the parts concentrically. For this reason, measures have been taken to place the filling ring at the back of the socket at the same time as the socket is formed, and a filling link is attached to the core mold for socket forming in advance to remove the softened pipe end. Methods have come to be adopted in which molding is performed by inserting a core mold into the softened tube end, or by inserting a core mold equipped with a filling ring into the softened tube end. However, even if a socket is formed by fitting a filling ring into a core mold, the purpose cannot be achieved unless the filling ring is left in the socket when the mold is removed. Therefore, it is necessary to use a filling ring whose maximum outer diameter is slightly larger than the outer diameter of the insertion tube or the inner diameter of the insertion tube corresponding part of the socket, and press it with an outer mold during molding, or use a resin material. Measures are taken to ensure that the filling link remains deep within the socket by utilizing the curing shrinkage or shrinkage elasticity of the filling link. On the other hand, synthetic resin pipes are manufactured by melting resin pellets, extruding them from a nozzle, stretching them, hardening them, and molding them, and manufacturing them with outside diameter regulations, but there are considerable restrictions on the inside diameter and wall thickness. There are spots and outside! Even the diameter is ±0.5
% tolerance is allowed. Therefore, it is necessary to select the outer diameter of the core mold and filling ring that take these into account. In addition, if the inner diameter of the filling ring is not determined taking these into account, a portion of the filling ring may protrude into a portion 3 of the pipe passage, creating resistance to the fluid as described above or causing solid matter to accumulate. result. Further, unless such a filling ring is arranged concentrically with the socket, the above-mentioned results will occur. Therefore, the filling ring 4, which is pre-fitted onto the core mold, must be held correctly concentrically with the core mold and in the correct plane. In order to satisfy these requirements, it has been proposed that the core mold be provided with holding means for the filling ring.
These holding means are held concentrically and planarly by a filling ring holding member configured to move radially in a centrifugal direction with respect to the core axis and a holding surface formed on the core. Therefore, the filling ring is held so as to be slightly raised above the fitting surface of the core mold, forming a stepped portion. However, this stepped portion obstructs the insertion of the tube end for forming the socket, which not only prevents smooth forming operations but also deforms the socket end and sometimes damages the filling ring. Ta. The present invention has been made with attention to these points, and as described above, when a filling ring is disposed at the rear end of the socket, and this filling ring is held in the molding core via a holding means, A socket configured in a gate so as to smoothly guide the insertion of a molded pipe into the socket, and which can be placed at the rear end of the socket while reliably correcting the flatness and roundness of the filling ring. This is a molding method, the gist of which is to use a filling ring in which the lower thin-walled portion of the socket abutting inclined surface of the filling ring is cut out toward the abutting inclined surface, and a filling ring support member arranged in a core shape. This is a socket forming method in which an abutting guide surface is formed that coincides with the cutout of the filling ring and the abutting inclined surface to hold the filling ring and expand the diameter of the insert forming tube. The present invention will be explained below based on the drawings.

The figure shows one example of a specific implementation of the present invention, and the present invention is not limited to the use of the illustrated core mold, but may be used with other molding core molds, or with other molds. It can also be used as a filling ring support means. These can be implemented by other means or by changing the shape within the scope or spirit described below. Figures 1 and 2 show examples of the socket part in which the filling ring is disposed and the means for molding the socket part. FIG. 3 is a cross-sectional view illustrating the relationship of the socket pipe for molding the socket, and FIG. 3 is a partial cross-sectional view illustrating the remaining means of the filling ring. In these figures, 1 indicates a socket pipe, and the socket pipe 1
As described above, the socket 3 is formed at the end. The socket 3 in the figure is simply an example into which the insertion tube 2 is inserted, but if necessary, the inner diameter may be increased to provide an elastic backing, or a protrusion for mooring the elastic backing may be used. It is possible to form a free joint by using an undercut screw having a core with stripes or grooves, or by using an outer diameter screw. Reference numeral 4 indicates an inclined portion, and the filling ring 5 is disposed on the inner surface side of the inclined portion 4.

However, these moldings are performed using a core mold 6 as illustrated in FIG.
The core mold is formed of a socket molding/forming body 7, a guide body 8, and a wall surface 10 formed at the boundary between these bodies. A regulating flange 7'' is formed.A guide slope 9 is formed at the tip of the guide body 8.The wall surface 10 is perpendicular to the core axis.
formed by a surface. On the other hand, the filling ring 5 is composed of a top portion 5a, an inclined surface 5b, and a bottom portion 5c, and is fitted into the guide body portion 8 of the core mold 6 and placed with its vertical height surface in contact with the wall surface 10. Therefore, as illustrated in FIG. 1, in a pipe joint in which the socket tube 1 and the insertion tube 2 have the same outer diameter, the outer diameter A of the socket molding body 7 of the molding core mold 6 is equal to that of the insertion tube 2. The outer diameter B of the guide body 8 is formed by the minimum inner diameter within the deviation range of the inner diameter D of the socket tube 1. In addition, the inner diameter C of the filling ring 5 needs to be larger than the maximum inner diameter within the deviation range of the inner diameter D of the socket pipe 1 so that the filling ring 5 does not protrude into the pipe passage, which further adds safety. The inner diameter C is chosen. The filling ring 5 mounted on the guide body 8 therefore necessarily forms a gap E, which gap E appears on the underside when the core mold 6 is applied horizontally.
Furthermore, the socket pipe 1 inserted along the guide barrel 8 has the deviation range described above, and the filling ring 5, which is inserted concentrically with the guide barrel 8, may be arranged eccentrically.
Therefore, the applicant has already proposed that the filling ring arrangement part of the guide body 8 of the core mold 6 is provided with concentric support means for said ring, or that the guide body 8 is provided with concentric guide means for the socket tube 1. is suggesting. In addition, the present inventors formed the maximum outer diameter of the filling ring 5 to be larger than the outer diameter A of the forming body 7 in order to leave the filling ring in the socket forming part, and as shown in FIG. A method of mooring is carried out by utilizing the elasticity of the tube flesh of the filling ring 5 to contract beyond the top 5a of the filling ring 5. If necessary, we are also considering a method of molding this part by applying pressure to the outer mold. On the other hand, the present inventors have discovered that although the filling ring 5 is molded so as to ride on the inner surface of the socket inclined portion 4 while being in close contact with the inner surface, the inclined surface 5 of the filling ring 5 after hardening is
It was discovered that the hem portion 5c of the sleeve 5c was raised above the inner surface of the socket tube 1. That is, as shown in FIG. 3, a gap indicated by H is formed on the slope side of the skirt portion 5c. Various causes of these problems were studied, and an attempt was made to make the inclined surface 5b of the filling ring 5 a circular surface as shown in the figure to smooth and equalize the extension guidance of the softened resin pipe wall, but sufficient results were not always obtained. That is, regarding these causes, the diameter is expanded by the inclined surface 5b of the filling ring 5, and the top portion 5
The tube wall that has passed beyond point a is elastically deformed and contracts the tube wall in the H section, and the curved surface tends to contract as it hardens, or the inner tube wall expands outwardly. Since the inner side is subjected to a compression action and an expansion action, it is conceivable that the pipe wall is displaced as shown by the dotted line 12 due to these recovery strains. On the other hand, these gaps H are undesirable like the space formed at the distal end of the insertion tube 2 described above. Therefore, the inventor cut off the bottom portion 5c of the filling ring 5, and this cutting was done at an elevation angle from the bottom surface of the filling ring 5 toward the inclined surface 5b, as shown in FIG.
The idea was to form the gap into a gentle concave part to prevent fluid disturbance and solid matter from stagnation. Also, the hem 5c of the filling ring 5
By cutting out the thin wall part of the filling ring 5, it was possible to make handling and manufacturing easier, but on the other hand, the tip 13 of the cut out part was placed farther away from the surface of the guide body 8 of the core type. . Therefore, when forming the socket, the tip of the socket tube 1 hits the tip 13 of the filling ring 5, and even if it is only temporary, the tube wall swells as shown by the dashed line 14 in FIG. 4, which prevents smooth diameter expansion molding. inhibit. Moreover, this obstruction caused damage to the end face of the socket pipe 1, and even caused damage to the filling ring 5 when the filling ring 5 was thin. Further, as described above, the left side of the filling ring 5 in the drawing needs to be configured with a surface perpendicular to the tube axis, and this is supported by the wall surface 107 formed on the core mold 6. Then, the filling ring 5 is inserted into the wall surface 10 by the insertion pressure of the socket pipe 1 or the press-fitting of the core mold 6.
The contact surface in the height direction of the socket pipe 1 is compressed.
The tip end surface of the filling ring 5 may not be a vertical plane, or the entire periphery may not be a plane, and the filling ring 5 may not be pressed evenly. Therefore, the filling ring support means not only supports the filling ring 5 by urging it in the centrifugal direction, but also supports the filling ring 5 on the wall surface 1.
It is necessary to support it so that it is in pressure contact with zero. However, in the present invention, a cutout is formed in the filling ring 5 as described above, and the inner surface of the cutout is formed at an elevation angle as described above, which is extremely convenient for pressing the filling ring against the wall surface 10. . That is, in the present invention, a part of the filling ring support member is used as the hem of the inclined surface 5b to constitute the guide surface of the socket pipe 1, and the filling ring 5 is brought into pressure contact with the wall surface 10 to form a concentric perfect circle of the filling ring 5. This achieved both degree and flatness retention. Specific examples of implementing the present invention will be described below.

FIG. 5 is a partially sectional side view in which the present invention is applied to a device in which the supporting member of the filling ring holding means provided on the core type moves in the centrifugal direction along an inclined surface, and FIG. FIG. 7 is a partially sectional side view showing the present invention applied to another core type. In Figures 5 and 6,
A recess 16 is formed in the filling ring arrangement portion of the core mold 6, and the bottom surface of the recess 16 forms a tapered inclined surface 17. On the other hand, the guide body of the core mold 6 is composed of a sliding ring body 19, and the sliding ring body 19
The inner central protrusion is hermetically joined to the narrow diameter part of the core mold, and both sides thereof are hermetically joined and supported by the protrusion formed in the core mold and the cover plate 20, respectively. Air chambers 21 and 22 are formed before and after the central protrusion, and the air chambers 21,
22 is connected to passages 23 and 24. A pressure medium, for example air pressure, is then introduced into these channels. On the other hand, a large number of support members 15 are arranged radially in the first recess 16, and the support members 15 form a cavity 26 in which the ring spring 18 is arranged. That is, a large number of support members 15 arranged in the recess 16 have one ring spring 18,
Hollow space 26 in each support member! It penetrates and is pressed against the inclined surface 17, and is urged and held along the inclined surface 17 in the diameter reduction direction. The diameter reduction direction is regulated by the rear end surface of the sliding ring body 19. Therefore, the top of the support member 15 has a hill portion 2.
As shown in FIG. 6, the hill portion 25 protrudes from the top surface of the sliding ring body 19, which corresponds to a core-type guide body portion, and forms an inclined surface 5b of the filling ring 5. , and the rear side thereof is formed to join with the cut surface of the filling ring 5. Figures 5 and 6 show the air chamber 22.
The pressure medium is introduced 4 and the sliding ring body 19 retreats, and the support member 15 supports the filling ring 5 in the centrifugal direction, and in this state the socket pipe 1 is guided. It is. Therefore, the distal end surface of the socket pipe is temporarily attached to the support member 15.
Since the diameter is expanded along the hill portion 25 of the filling ring and then along the inclined surface 5b of the filling ring, the above-described drawbacks of the conventional method can be completely eliminated. At the time of demolding, by moving the sliding ring body 19 forward, the supporting member 15 moves forward as shown by the dotted line and moves in the diametrical direction. FIG. 7 shows an example in which the present invention is implemented using another core mold, in which the core mold 6 has a socket molding body and a small-diameter guide body 28 which are each constructed separately.
A cavity 29 is formed in the mounting surface. However, at the tip of the socket-forming body of the lever, the filling ring holding part forms a small diameter part 33 of the outside diameter of the cylinder with the guide body 28, and the small diameter part 33
A radial slit 32 is formed in. The lever slit 32 is continuous with the void 29. On the other hand, a protrusion 28a that fits into the slit 32 formed in the small diameter portion 33 is formed on the installation facing surface of the guide body 28, and the protrusion 28a fits so as to close only a part of the slit 32. The guide body 28 is screwed onto the socket-shaped body. Therefore, radial slits 32 are formed on the circumferential surface of the small diameter portion 33 . On the other hand, a conical drum 31 is arranged in the empty space 29,
The conical drum 31 passes through the core molded body and guides the guide body 28.
It is fixed to a sliding shaft 30 supported by. and small diameter part 3
A support member 27 is inserted and disposed in the slit 32 of No. 3, and the support member 27 is biased and held in the diameter reduction direction by the ring spring 18 in the same way as the previous support member, and slides into contact with the circular drum 31. The sliding shaft 30 is moved in the direction of the arrow by suitable means.
Thus, at the top of the support member 27, a hill 25 similar to that of the previous example is formed, which guides the shaped socket tube 1 on its outer side and, by means of a thrust acting on its inner side, causes the filling ring 5 to The filling ring can be held by pressing the ring against the wall surface. Various means other than these are used for the sliding movement means of the support member, and as mentioned above, the core mold is also provided with alignment guide means for the molded socket pipe, or the socket molded body A locking ring for an elastic backing formed on the inner surface of the socket may also be provided, or a means for simultaneously forming locking protrusions and grooves for the backing may be provided.In short, the filling ring and the filling ring may be attached together. As long as the supporting member is configured as described above, the present invention is satisfied. As described above, the present invention has devised the shape of the filling ring, and the supporting member has a surface that matches the slope of the filling ring, so that the introduction of the socket forming tube is smooth and the forming is easy and reliable. I was able to do it. In addition, since the support member is formed with a surface that comes into contact with the cut end surface of the filling ring, the filling ring is held in pressure contact with the wall surface of the core mold and is held securely, so that it can be placed extremely accurately at the back end of the molding socket. It has become.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a pipe joint with a filling ring arranged, Figure 2 is a sectional view illustrating the relationship between the core mold showing the molding of the socket, the filling ring, and the socket pipe, and Figure 3 is a sectional view of the filling ring. FIG. 4 is an explanatory cross-sectional view showing the relationship between the molded pipe wall and the molded pipe wall. FIG. 4 shows another example of FIG. 3 and shows a cross section of the filling ring for the present invention. FIG. 5 is a partially cutaway side view showing a specific example of a core mold embodying the present invention, FIG. 6 is a partially enlarged explanatory view of FIG. 5, and FIG. FIG. 2 is a partially cutaway side view of a core mold that has been subjected to the above process. 1...Socket tube, 2...Insertion tube, 3...Socket part, 4...Slanted surface, 5
...Filling ring, 6... Core type, 7...
... Socket molding body, 8... Guide body, 9.
... Slope surface, 10 ... Wall surface, 11 ...
... Biting part, 12... Deformed part, 13... Tip part,
14...Bulge, 15...Supporting member, 16
...Empty space, 17...Slope, 18...
...Ring spring, 19...Sliding ring body, 20...
... Lid plate, 21, 22 ... Air chamber, 23, 2
4... Passageway, 25... Hill section, 26... Vacant space, 27... Support member, 28... Guide body, 29... ... Vacancy, 30 ... Sliding shaft, 31 ... Conical drum, 32 ... Slit, 33 ... Small diameter part.

Claims (1)

[Claims] 1 A socket in which an enlarged socket for pipe joining is formed at the end of a synthetic resin pipe, and a filling ring placed at the rear end of the socket is fitted in advance into a core mold for socket molding. In the molding method, the filling ring is a filling ring in which the lower thin wall part of the contact slope of the socket part is cut out toward the contact value slope, and the molding core mold is provided with a holding means to hold the filling ring concentrically. , a synthetic resin characterized in that the filling ring supporting member of the holding means is formed with a molding guide surface that coincides with the abutment slope of the socket portion of the filling ring, and guides the insertion molding tube to expand its diameter. Method for forming pipe sockets.