JPS6031948A - Molding equipment for diameter-widened port section of synthetic-resin tube body - Google Patents

Abstract

PURPOSE:To mold the internal form of a tube body accurately to predetermined size by constituting a molding equipment for the diameter-widened port section of the synthetic-resin tube body in such a manner that a stepped section is formed on a border between a front die and an intermediate split die and the diameter of the front end of the intermediate split die is made smaller than that of the rear end of the front die. CONSTITUTION:A stepped section F is formed on a border between a front die 11 and an intermediate split die 13, and a tube body 1 intrudes into an indentation on the intermediate split die 13 side generated by the stepped section F while it fast stickes to a taper 11a in the front die 11 firmly extending over a wide range. Since airtight properties are ensured among the tube body 1 and the front die 11 and a rear die 13, an intake effectively functions when air is sucked through intake paths 14-17, and the tube body 1 can be molded accurately to a predetermined inner-diameter shape. The intake is stopped while water is sprinkled over the tube body 1 to solidify the tube body, and the diameter of the intermediate split die 13 is reduced and the tube body 1 is pulled out.

Description

[Detailed description of the invention] The present invention relates to a device for obtaining an enlarged diameter socket having a shaped bulge.

As one means for connecting synthetic resin pipe bodies such as vinyl chloride resin, there is a means shown in FIG. 1. That is, an enlarged-diameter receptacle 2 is provided at the end of one tube 1, and the other tube 1 is inserted into the expanded-diameter receptacle 2 to establish the connection. This socket part 2 is formed with an annular bulging part 3 having a storage groove 3a on the inner periphery, and an annular rubber seal member 4 accommodated in this storage groove 3a allows the space between the tubes 1 and 1 to be closed. A seal has been made. In addition, at the end of the tubular body 1, the diameter of each part is A. B, C, and D have a relationship of A<D<B<C.

A conventional molding apparatus for obtaining the enlarged diameter socket 2 of the tube body 1 is constructed as shown in FIG. This device includes a front mold 11, a rear mold 12, and an intermediate split mold 13 provided between these molds 11 and 12 and capable of expanding and contracting the diameter. The rear part of the front mold 11 has a taper lla, and the diameter gradually increases toward the rear end. The intermediate split mold 13 has a larger diameter than the front mold 11 and the rear mold 12 when the diameter is expanded, and has a taper 13a continuous with the taper lla of the front mold 11 in the front part, and a taper 13a in the rear part. It has an annular protrusion 13b for forming the annular bulge 3 of the tube body 1.

In addition, between each mold 1 1, 1 2.1 3, an intake passage 14,
15 is formed, and a plurality of air intake passages 16 are also formed radially inside the intermediate split mold 13. A main air intake passage 17 is formed in the center of the intermediate split mold 13 and the rear mold 12, and is connected to the air intake passages 14, 15, and 16.

Then, when the heated end of the tubular body 1 is inserted from the front mold 11 with the diameter of the intermediate split mold 13 expanded, this end is connected to the taper 11a of the front mold 11 and the taper 1 of the intermediate mold 13.
3a, the diameter expands, and further passes over the annular projection 13b to reach the rear mold 12. Thereafter, by inhaling air through the air intake passages 14-17, the tubular body 1 is formed into the final shape shown in FIG.

However, the above molding apparatus has the following disadvantages.

(a) Since the taper lla and the taper 13a are continuous and constitute an almost integral taper, the pipe body 1 has a taper 1
3a, they contact each other over the entire area, but taper lla makes contact only in a narrow range (indicated by E in the figure).

3-(b) Since the intermediate split mold 13 is composed of a large number of divided pieces, it is difficult to produce a perfect circular cross-sectional shape, and furthermore, the cross-sectional shape becomes distorted due to long-term operation.

While the front mold 11 has a perfect circular cross section, the intermediate split mold 13 has a non-perfect circular cross section, so the tube body 1 is in close contact with the taper lea, resulting in gaps here and there.

As a result, airtightness cannot be ensured between the tube body 1 and the front mold 11, so the intake air does not work effectively and it is difficult to accurately mold the inner shape of the tube body 1 to predetermined dimensions. be. Especially tube body 1
The storage groove 3a of the bulge 3 requires high precision in order to store the seal member 4 and obtain a predetermined watertightness, but this can be achieved with the above-mentioned device.

For this reason, in reality, an outer mold is placed around the above device,
This outer mold presses the tubular body 1 against the intermediate split mold 13 to obtain a predetermined inner shape. However, in this case,
Disadvantages: Marks of the outer mold may be left on the outer circumferential surface of the tube 1, reducing its commercial value, and because of the outer mold, it takes time to cool the tube 1 by pouring water on it, resulting in a longer processing cycle. There is. Various proposals have been made in the past regarding means for obtaining the inner shape of a tube body with high accuracy by effectively utilizing intake air without using an outer mold.

For example, there is a device in which a rubber ring is installed on the outer peripheral surface of the front mold and, if necessary, on the outer peripheral surface of the rear mold, and the rubber ring ensures airtightness between the mold and the tube body.

However, this device has the disadvantage that its useful life is short because the rubber ring comes into contact with the heated tube and deteriorates.

The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks, and its gist is to provide a step between the front mold and the middle split mold, so that the front end of the middle split mold is connected to the rear end of the front mold. This is a device for molding an enlarged diameter socket of a synthetic resin pipe with a smaller diameter.

Hereinafter, one embodiment of the molding apparatus of the present invention will be described with reference to FIG. In the apparatus used in this example, the second
Portions corresponding to the conventional apparatus shown in the figures are given the same numbers in the figures, and detailed explanations thereof will be omitted.

Taper lla of front mold 11 and taper 1 of intermediate mold 13
3a have approximately the same taper angle, but are not continuous with each other, and a step F is formed at the boundary. That is, the diameter of the front end of the intermediate split mold 13 is smaller than the diameter of the rear end of the front mold 11. Note that this step B is approximately 0.
It is 51.

The rear mold 12 is tapered so as to gradually expand in diameter from the front end toward the rear end. This taper angle e is about 2 degrees. The diameter of the front end of the rear mold 12 is the same as or slightly smaller than the diameter of the rear end of the front mold 11.

Next, the operation of the device having the above configuration will be explained. Fourth
As shown in the figure, the end of the preheated tube body 1 is inserted from the front mold 11 with the intermediate split mold 13 expanded in diameter.

The end of the tube body 1 is expanded in diameter by a taper lla formed at the rear of the front mold 11 and a taper 13a formed at the front of the intermediate mold 13, and further formed at the rear of the intermediate mold 13. It passes over the annular projection 1311 and reaches the rear mold 12.

In this state, since a step F is formed at the boundary between the front mold 11 and the intermediate split mold 13, the flesh of the tube body 1 enters the depression on the intermediate split mold 13 side created by this step F1, and It tightly adheres to the taper lla of the front mold 11 over a wide range (indicated by G in the figure). On the other hand, the diameter of the tip of the tubular body 1 is reduced by natural cooling, but since the rear mold 12 is tapered, it tightly adheres to the outer peripheral surface of the rear mold 12.

As mentioned above, the tube body 1, the front mold 11 and the rear mold 1
Since airtightness is ensured between the intake passages 14 and 17
When air is taken in through the tube, the air works effectively and the tube body 1 can be accurately formed into a predetermined inner shape.

Thereafter, the intake of air is stopped, water is poured onto the tubular body 1 to solidify it, and the diameter of the intermediate split mold 13 is further reduced to remove the tubular body 1.

In the device of the present invention, the step F may be obtained by forming an annular convex portion 20 at the rear end of the front mold 11 as shown in FIG. 5, or as shown in FIG. Intermediate split mold 13
The step F may be obtained by forming an annular recess 30 at the front end of the ring.

Further, the intermediate split mold 13 may be configured by being divided into a split mold having an annular projection 13b and a split mold having a taper 13a.

As explained above, the present invention provides a step at the boundary between a front mold having a taper at the rear and an intermediate mold having a taper at the front, and at this boundary, the front end of the intermediate mold is connected to the rear end of the front mold. It has a smaller diameter.

Therefore, the taper of the front part of the tubular body is firmly and tightly attached to each other over a wide range, and airtightness is ensured between the tubular body and the front part. The inner shape is accurately molded to the specified dimensions. Moreover, since there is no need to use an outer mold, it is possible to eliminate the inconvenience of leaving marks of the outer mold on the outer peripheral surface of the tube, and the time for cooling the tube can also be shortened.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the connecting structure of the pipe body, Fig. 2 is a side view of the upper half showing the process of forming the enlarged diameter socket of the pipe body using a conventional device, and Fig. 3 is a side view of the upper half of the pipe body using the present invention. FIG. 4 is a side view of an upper half showing the process of molding the enlarged diameter socket of a tube body using the same device; FIG. FIG. 6 is a side view of the upper half of the main part showing another embodiment of the present invention. 1...Synthetic resin pipe body, 2...Enlarged diameter socket, 3...
Annular bulging portion, 4... Seal member, 11... Front mold,
lla... Taper, 12... Rear type, 13... Intermediate split type, 13a... Taper, 1.3b... Annular projection, F... Step applicant Representative of Sekisui Chemical Co., Ltd. Fujinuma profiteering Figure 1 Figure 2 Figure 5 Figure 6 Figure 11 ;j 11 1j

Claims (1)

[Claims] A front type having a taper at the rear, and an enlarged diameter type having a taper at the front and an annular projection at the rear. Equipped with an intermediate split mold capable of diameter reduction and a rear mold, the end of the heated synthetic resin pipe is inserted, and air is taken in through an air intake path formed at least between each mold. In an apparatus for molding an enlarged-diameter receptacle having an annular bulge for storing an annular sealing member, a step is provided at the boundary between the front mold and the intermediate split mold, and the front end of the intermediate split mold is A device for molding an enlarged diameter socket of a synthetic resin pipe body, characterized in that the diameter is smaller than the rear end of the mold.