JPS6045054B2 - Molding method for expanded diameter socket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming an enlarged diameter socket at the end of a thermoplastic resin pipe, and is particularly devised so that the outer peripheral surface of the enlarged diameter socket can be shaped precisely and beautifully. This paper relates to a molding method.

The most common method for forming an enlarged diameter socket made of a thermoplastic resin material such as vinyl chloride resin is to reheat the end of a headless pipe formed by a selective molding method or the like. One example is a so-called sleeve processing method in which the core is softened and a core mold for socket forming is pushed into the open end to expand the diameter. Since this method is relatively easy to work with and can be applied to forming many types of expanded diameter sockets, it has come to occupy an extremely important position in the pipe processing field, and its improved technology is also described in 1-
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As part of this project, a method was proposed in which the inner circumferential surface of the enlarged diameter socket was regulated by a core mold for socket molding, and the outer periphery was regulated by an outer mold, and the inner and outer surfaces could be formed precisely. There is.
In addition, when expanding the diameter of the pipe end, the resin at the end of the pipe is stretched as the diameter is expanded, and the pipe wall at the expanded diameter part becomes thinner, which may cause problems in water supply piping, etc. By forming a certain space around the mold, arranging the outer mold, and expanding the diameter while filling the space with resin at the end of the tube, it is possible to create an expanded diameter socket that prevents thinning of the wall. It has been confirmed that this method can be used, and some of them have entered the stage of practical application. However, the following unavoidable problems remain in the method of regulating the inner and outer surfaces of the diameter-expanding socket using a core mold and an outer mold. In other words, the outer mold that regulates the outer circumferential surface of the diameter-expanding socket must be of split mold type due to necessity in the demolding process; The resin at the end loosens in the demolding direction due to pressure, and a gap is created at the dividing boundary of the outer mold, and the resin at the end of the tube protrudes into this area, causing buffling on the outer periphery of the diameter expansion process, or creating line-ruled lines. Something happened. This tendency is particularly noticeable in thickening molding methods that require considerably strong indentation pressure during processing, and is a factor that reduces the commercial value of molded products. The inventors of the present invention focused on the above-mentioned circumstances, and the outer mold did not loosen even when a considerably strong indentation pressure was applied during the molding and 5th thickening molding processes, and the outer circumferential surface of the enlarged diameter part was precisely formed. As a result of extensive research in an attempt to provide a method that would allow for beautiful molding, the present invention was finally completed.

In other words, the configuration of the molding method according to the present invention is a method of molding an enlarged diameter socket by applying a core mold for secondary molding and a split type outer mold to a thermoplastic resin pipe. After a tapered surface is provided and the outer mold is integrated, a tightening member that moves in the axial direction of the core mold is moved along the tapered surface to forcibly tighten the outer mold, and the mold is formed. The gist is that the outer mold is tightened with an external pressure greater than the resin pressure due to the deformation of the tube, and in particular, the outer mold is forcefully tightened from the outer periphery by a tightening member, and the mold is press-molded. By preventing loosening of the outer mold during the process, the outer circumferential surface of the enlarged diameter molding part can be molded precisely and beautifully. The configuration and effects of the present invention will be explained in detail below based on the drawings which are examples, but the drawings are only illustrative of the most typical ones, and in keeping with the spirit of the above and later explanations, appropriate explanations will be given. Any modification and implementation is included within the technical scope of the present invention.

1 to 6 are process explanatory diagrams illustrating the present invention.
6 are explanatory cross-sectional views of essential parts, and FIGS. 2 and 3 are cross-sectional views corresponding to lines 1--2 and 2--2 in FIG. In addition, 1st, 4th ~
6 is a cross-sectional view corresponding to the I-1 line in FIGS. 2 and 3. An outline of the apparatus shown in the figure will be explained below. In the figure, reference numeral 1 denotes a core mold for molding sockets, and the core mold 1 is supported through approximately the center of a slide member 3 that is slidably disposed on slide pars 2a, 2b, 2c, and 2d. It is constructed so that it can move forward and backward independently of the slide member 3 by means of a cylinder 4 provided at its back. Further, in the front part of the slide member 3 (on the left side in FIG. 1), as shown in FIG.
, 5b are configured to be movable forward and backward in the direction of the enlarged diameter forming portion 1a of the core mold 1 by means of cylinders 6a and 6b. And outer mold 5
Tapered portions 7a, 7b are provided on the outer periphery of the tips of a, 5b.
form. Furthermore, a tightening member 8 is provided in front of the outer molds 5a and 5b.
This tightening member 84 operates the slide pars 2a, 2b, 2c, 2 by operating the cylinders 9a, 9b.
d so that it can move forward and backward in the left and right directions shown in FIG. A tapered clamping surface 10 corresponding to the tapered parts 7a and 7b formed on the outer periphery of the outer molds 5a and 5b is provided in the center of the clamping member 8, and the clamping member 8 is moved to the right in FIG. When moved, the outer molds 5a, 5b are tightened from the outer periphery, while when moved to the left in FIG. 1, the tightening is released. In addition, core mold 1, cylinders 6a, 6b and 9a
, 9b, etc. are constructed so as to be able to move integrally with the slide member 3 via appropriate connecting members, and by moving the rod 11 forward and backward, these as a whole can be moved into the slide buffs 2a, 2b, 2c. , 2d to the left and right in FIG. And slide par 2a,
A chuck 13 is disposed on the bracket 12 that supports the left ends of the cylinders 2b, 2c, and 2d, and the thermoplastic resin pipe 15 is gripped or released by operating the cylinder 14. Next, the steps for implementing the present invention using the apparatus configured as described above will be explained.

First, the rod 1 is pulled to the right in the drawing, and the core mold 1 and the like are retracted and placed in the right direction, and the processed end of the heated and softened thermoplastic resin pipe 15 faces the core mold 1 concentrically. It is gripped and fixed by a chuck 13. In this state, the core mold 1 is retracted to the rear, and the outer molds 5a and 5b are arranged to surround the core mold 1, and are strongly pressed from the outer periphery by the tightening member 8. (Figure 1).
In this case, the gap 16 formed between the core mold 1 and the outer molds 5a and 5b shall be set appropriately according to the wall thickness of the intended expanded diameter socket. The dimensions of the outer molds 5a and 5b are adjusted so that a gap 16 equal to or greater than the wall thickness of the main pipe portion 15 is formed. Then rod 1
1 to the left in FIG.
Advance in five directions. and the tube 15 as shown in FIG.
The end portion of the rod 11 is gradually guided into the gap 16, and when the gap 16 is filled with the tube end resin, the advancement of the rod 11 is stopped. In this state, the open end of the tube 15 is appropriately expanded in diameter (or expanded in thickness) according to the shapes of the core mold 1 and the outer molds 5a and 5b. In this pushing process,
Since the outer molds 5a and 5b are forcibly tightened from the outer periphery by the tightening member 8, the outer molds 5a and 5b are loosened by the pressure of the pressed resin, and the resin is applied to the dividing boundary surface of the outer molds 5a and 5b. This eliminates the possibility of burrs or creases occurring on the outer circumferential surface of the molded product due to leakage. After that, the expanded diameter part is cooled and hardened, and the outer mold 5a,
5b is demolded.

To do this, first operate the cylinders 9a and 9b to advance the tightening member 8 forward, and after separating from the outer molds 5a and 5b (
(Fig. 5), cylinders 6a, 6b as shown by phantom lines in Fig. 2.
The outer molds 5a and 5b are removed from the left and right sides. Next, after loosening the chuck 13, the core mold 1 and the tube 15 are pushed out using the cylinder 4 as shown in FIG. After performing the cooling process, the core mold 1 is retracted to the right in FIG.
The enlarged diameter molded portion is removed from the core mold 1 and the molding operation is completed. In this case, it is advantageous to provide a suitable protruding member at the expanded diameter end regulating step portion 1b of the core mold 1, since the core mold 1 can be demolded more smoothly. Note that the expanded diameter molded portion may be completely cooled and hardened before removing the outer molds 5a and 5b, but from the standpoint of shortening the cooling time, it is possible to expand the expanded diameter portion before removing the outer molds 5a and 5b. It is advantageous to adopt a method in which the diameter molded part is precooled to such an extent that it does not naturally deform, and after the outer molds 5a and 5b are removed, the outer periphery of the diameter expanded molded part is directly cooled by water spraying or the like. The method of the present invention is carried out, for example, as described above, but its greatest feature is that in the diameter expansion molding process, the outer molds 5a and 5b are forcefully clamped by the clamping member 8, and the outer molds 5a and 5b are forcefully tightened by the pressing resin pressure. This is to completely prevent the molds 5a and 5b from loosening, and to eliminate burrs and ruled lines that appear in the enlarged diameter molded portion.

Therefore, as long as the characteristics described above can be effectively exhibited, the core mold 1,
Outer molds 5a, 5b. The individual configurations of the tightening member 8, the chuck 13, etc. and the actuator configuration, the overall configuration, the operating mechanism, etc. are not limited to those shown in the illustrations, and may be modified as appropriate by those who practice the present invention. Of course it is possible to do so. for example,
The core mold 1, outer molds 5a, 5b, etc. are fixed to the slide member 3 and slid along the guide bars 2a to 2b. In addition, as for the movement source, in addition to hydraulic, electric, and air cylinders, a solenoid mechanism, a link mechanism, a rack and pinion mechanism, etc. can be appropriately selected and adopted. In addition, the tightening member 8 is basically the outer mold 5a,
5b can be forcefully tightened from the outer periphery, the structure is based on the tapered portions 7 provided on the outer molds 5a and 5b.
It can be changed as appropriate depending on the shape and structure of parts a and 7b, and in addition to the configuration in which the outer molds 5a and 5b are evenly tightened tightly from the entire circumference as shown in the illustration, it is also possible to partially tighten the outer molds 5a and 5b in two or three or more places. It is also possible to adopt a configuration in which the material is tightened with strong pressure. Regarding the gripping mechanism in the chuck 13 portion, the configuration of the gripping mechanism itself is not particularly limited as long as it can grip and fix the thermoplastic resin tube 15, which is the workpiece, concentrically with the core mold 1. 7 and 8 are partially cutaway side views of essential parts illustrating another enlarged diameter socket obtained by the present invention, and FIG. 7 shows a packing mounting groove 15b formed on the inner periphery of the enlarged diameter part 15a. Fig. 8 shows a re-enlarged diameter section 15c for attaching a packing at the open end of the enlarged diameter section 15a, and a packing latched to the inner periphery of the re-enlarged diameter section 15c. ring 1
7 is planted and fixed to serve as a socket for connecting the packing.
18 indicated by chain lines each indicate an elastic packing for sealing.

These socket parts as shown in FIGS. 7 and 8 are used for the core mold 1 and the outer molds 5a and 5b in the apparatus as explained in FIGS. 1 to 6.
It can be molded by the same procedure as described above by appropriately changing the shape of , and it goes without saying that modifications to these degrees are within the technical scope of the present invention. 7th,
When molding a socket as shown in Figure 8, a part of the core mold 1 becomes undercut and cannot be removed from the mold. It is sufficient that the core mold 1 is housed in a suitable position in the mold 1 and configured such that the core mold 1 can be easily removed. The present invention is constructed as described above, but the point is that the outer mold of the split mold type that regulates the outer circumferential surface of the diameter-expanding socket part is forcefully tightened by a tightening member, and the diameter-expanding molding process or Since we have reliably prevented the phenomenon of the outer mold loosening due to the pressure of the injected resin during the thickening molding process, extremely precise and beautiful expansion can be achieved without creating burrs or creases on the outer periphery of the diameter expansion socket. This allows a diameter socket to be formed.

[Brief explanation of drawings]

j The drawings illustrate the present invention, and FIGS. 1 and 4 to 6 are sectional views of essential parts, and FIGS. 2 and 3 are sectional views corresponding to lines 1 and 2 and 2 and 3 in FIG. 1. Note that FIGS. 1 and 4 to 6 are views corresponding to the I-1 line cross section in FIGS. 2 and 3. 7 and 8 are partially cut away main part side views illustrating other socket parts obtained by the present invention. 1...
...Core mold for socket molding, 1a...Diameter expansion molding part,
2a, 2b, 2c, 2d...Slide par, 3
...Slide bar member, 4...Cylinder,
5a, 5b...Outer mold, 6a, 6b...Cylinder, 7a, 7b...Tapered portion, 8...
...Tightening member, 9a, 9b...Cylinder, 10
...Tapered tightening surface, 11...Rod, 12...Bracket, 13...Chuck, 14...Cylinder, 15... Thermoplastic resin pipe, 16... Gap, 15a... Expanded diameter part, 15
b...Backing installation groove, 15c...
Expanded diameter part for attaching backing, 17... Ring for packing locking, 18... Elastic packing for wool.

Claims (1)

[Claims] 1 In a method of forming an expanded diameter socket by applying a core mold for secondary molding and a split type outer mold to a thermoplastic resin pipe, a tapered surface is provided on the outer periphery of the outer mold, and the outer mold is integrated. After that, a tightening member that moves in the axial direction of the core mold is moved along the tapered surface to forcefully clamp the outer mold, using an external pressure that is greater than the resin pressure caused by the deformation of the pipe to be molded. A method for forming an enlarged diameter socket, characterized in that the outer diameter is tightened.