JPS58138614A - Molding of plastic tube end socket - Google Patents

Abstract

PURPOSE:To manufacture precisely sockets with different inner diameters by a method wherein the mold portion for molding an elongation portion is made higher in temperature than the remaining mold portions and after a half socket is molded the elongation portion is molded by another mold by the remaining heat. CONSTITUTION:A plastic tube 1 with a heated tube and 1A is forced in the axial direction into the molding space 4 between the internal mold 2 composed of the inserting portion 4A with a diameter D equal to that d of the synthetic resin tube 1, the enlarged diameter portion 4B, the horizontal portion 4D on the packing groove and its forward horizontal extension portion and the external mold 3 to mold a half socket. During this molding, the extension molding portion L of the tube 1 is heated at a high temperature while the other portions are heated at the plasticizing temperature at which the tube cannot be restored after deformation. Then, after the half socket is molded, it is released from the mold, another mold 6 is inserted into the extension molding portion L, the diameter of the mold 6 is enlarged, the rubber ring mounting portion 1B', etc. are molded by the cooperation with the external mold 7 in the remaining heat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a plastic tube end.

Conventionally, as shown in FIG. 1, a plastic tube A with a connection socket A1 enlarged in diameter at the tube end AQ has been widely used.

Generally, the shape of the connection socket is an upwardly tapered portion B1;
and a horizontal portion B2. An enlarged diameter part B with an inner diameter larger than the outer diameter of the other pipe to be connected, and a front part of this enlarged diameter part B (
In the direction of arrow X), at least the upwardly tapered portion 01,
It has a good shape and has a backing mounting groove 0 consisting of a horizontal part 02 and a downwardly tapered part 03, and a mouth part connected to the downwardly tapered part 05 of the backing mounting groove 0, and is enlarged compared to the inner diameter of the mouth part. Both the diameter portion B and the backing mounting groove O have a larger inner diameter. Therefore, there was a problem that its molding was technically difficult.

That is, as a general method for the above-mentioned socket molding, a core body that can be reduced in diameter is used, but the structure of the core body that can be reduced in diameter is extremely complicated, and its operation is also difficult. There are certain drawbacks, and in some cases the core body is made of a material with rubber-like elasticity, and the core body is pulled out after molding by taking advantage of the elasticity1, but in this case, good molding accuracy cannot be achieved. There was a problem that it could not be done. Furthermore, a plastic tube whose tube end has been heated and softened is forcibly fitted onto the core body for tube socket molding, and then the above-mentioned plastic tube retains its elasticity but loses its plastic deformability. It has also been proposed to cool the synthetic resin tube and pull it out without reducing the diameter of the core, but in this case, there is a problem that it is difficult to increase the accuracy of the inner diameter dimension. In other words, for the purpose of improving the sealing performance of the backing mounting groove, it is necessary to precisely mold the surface that the backing directly contacts, but it is particularly difficult to mold the area shown in range E in Figure 1 properly. , there were drawbacks.

In view of the above, the present invention has been made for the purpose of providing a method for manufacturing a synthetic resin pipe that allows easy and highly accurate manufacturing of sockets with different inner diameters depending on the part, and includes a rising taper part and a water socket. 'An enlarged diameter part consisting of a flat part, and at least an ascending taper part, a horizontal part, and a descending chi in front of the enlarged diameter part; 9. '、Ka1. 7. It's a mounting groove. 2. In a method of molding a socket having an opening connected to the downwardly tapered part of the backing mounting groove into a part of the plastic pipe, the front side of the backing mounting groove is horizontally A half-socket shaped as an extension of the part is molded by press-fitting the end of the plastic pipe into the molding space between the inner mold and the outer mold, and during this molding, a mold for molding the extended part. The part is heated to a higher temperature than the part of the mold that molds the other parts, and after the half-socket molding, the extended part is heated under the residual heat, and the backing attachment part and the backing attachment groove over the enlarged diameter part, as well as the mouth part, are heated. It is characterized by being molded using a different mold than the one described above.

This invention will be explained below using an example of +4.4.

FIGS. 2 to 5 are explanatory diagrams showing the state of implementation of the present invention in the order of steps.

The method of molding a socket for a synthetic resin pipe according to the present invention begins with an insertion part 4A having a diameter approximately equal to the diameter d of the synthetic resin winnower 1 to be processed, and a horizontal part rising from the insertion part 4A through a tapered part. The inner metal part is made into an extension shape of the horizontal part 4D (corresponding to 02 in Fig. 1) of the backing mounting groove through the enlarged diameter part 4B that forms and the ascending taper part 40''. The plastic tube 1 with heated tube end IA is forced into the molding space 4 between the mold 2 and the outer mold 3'' in the axial direction (arrow P) as shown in FIG. During this molding, the extended molded part (L part) of the plastic tube 1 is heated to a high temperature as shown in Fig. 4, so that, for example, even after deformation, it will naturally return to its original state before deformation. For example, in the case of vinyl chloride pipes, the plasticizing temperature can be as low as 90°C.
Heat the other parts to a high temperature (4A).

Part 4B) is heated to a plasticizing temperature at which it does not recover after deformation, for example, about 70°C in the case of the above example, and more preferably, the plastic tube 1 is pressurized in the axial direction Q by the suppressing member 5, and the molding space is 4 to increase the wall thickness of the plastic tube, and then, after molding the half socket, the mold was removed, and as shown in FIG. Insert the mold 6 of
By expanding the diameter as shown in the figure, the rubber ring mounting portion IB'' of the enlarged diameter portion IB and the rubber ring mounting groove 10 are formed in cooperation with the newly placed outer mold 7 under the residual heat of the extended portion.
．． The downward taper portion ID and the mouth portion 11[i are formed, and the mold 6 is cooled and hardened in this state, and the mold 6 is reduced in diameter again and pulled out.

In the above, the rubber ring mounting groove-forming mold 6 is as follows:
As shown in FIG. 6, the shape has a length L extending over the mounting groove portion 10 of the rubber ring 8 and the rubber ring abutting portion IB" of the enlarged diameter portion IB, and has a hole on the entire surface where the rubber ring 8 comes into contact. 'It is configured to be molded by a mold 6.'

゛Also, even at the stage when the rubber ring mounting portion IB' and the groove 10 are being formed using the mold 6, in order to avoid thinning of this part and to guarantee the wall thickness, as shown in Fig. 5, A configuration may be adopted in which the end portion of the mouth portion 1m is pressed by the pressing member 5°.

The mold 6 is shaped to form the rubber ring mounting groove 10 and the rubber ring mounting portion IB', and is configured not to contact anything other than the rubber ring mounting surface (IB', 10). Therefore, when the mold 6 is inserted, it does not come into contact with the intermediate diameter part (IB part) of the socket and a space S is formed, but this part (IB part) remains in its original shape after deformation. Since the molded material is heated at a plasticizing temperature at which it does not recover, both the increased wall thickness and its enlarged diameter shape maintain the shape as originally molded.

Since the present invention is configured as described above, even when molding a pipe socket whose inner diameter at the back is larger than the opening diameter, the complicated mechanism required to mold them all at once can be avoided. There is no need to use a core device that can reduce and expand the diameter, and the inner diameter of the backing mounting part, including the mounting groove, can be precisely molded, making it easy to create a socket with good inner diameter precision. It has the advantage of being able to be manufactured.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a plastic pipe with a socket, Figures 2 to 5
The drawings are explanatory diagrams showing the implementation state of the present invention in the order of steps, and FIG. 6 is an explanatory diagram of the rubber ring portion. DESCRIPTION OF SYMBOLS 1... Synthetic resin pipe, IA... End, IB... Expanded diameter part, 10... Rubber ring mounting groove, 11c... Mouth part,
2... Inner mold, 3... Outer mold, 4... Molding space,
6, 7...Another mold, L...Extended shape part. r/IB

Claims (1)

[Claims] (1) An enlarged diameter part consisting of an ascending taper part and a horizontal part, and at least an ascending taper part, a horizontal part in front of the enlarged diameter part,
In a method of molding a socket at the end of a plastic pipe, the socket has a backing installation groove consisting of a downwardly tapered part and a mouth part connected to the downwardly tapered part of the backing installation groove, in which the horizontal part is formed in front of the packing installation groove. A semi-tatami opening with an extended shape is formed by press-fitting the end of the plastic pipe into the molding space between the inner mold and the outer mold, and during this molding, the mold part that molds the extended shape part is formed. is heated to a higher temperature than the part of the mold that molds other parts, and after molding the half and socket, the extended part is heated under the residual heat, and the backing installation part and backing installation groove over the expanded diameter part, and the mouth part are A method for molding a socket at the end of a plastic pipe, characterized by molding using a mold different from the above.