JPH046537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for manufacturing a hollow molded product in which additional parts are integrally and firmly fixed.

Conventional techniques Conventionally, hollow molded products such as pipes have been used with additional parts (inserts, anchors, etc.) such as brackets made of a material different from that of the hollow molded product. A bracket provided on the pipe allows the pipe to be attached to a fixed wall and placed in a predetermined position. When manufacturing a hollow molded product, a part of such a bracket is usually added to the parison and molded integrally with the parison. In this case, the first
As shown in the figure, a locking part 1a is provided protrudingly on a bracket 1 as an additional part, and this is covered with a parison 2, and this locking part 1a and the parison 2 are heat-sealed to form a bracket 1 and a parison 2. and to fix them together. However, since a mold release agent or the like is usually attached between the parison 2 and the bracket 1, it is difficult to heat-seal the parison 2 and the bracket 1, and the parison 6 does not reach the base of the locking part 1a, creating a space in that part. S is likely to occur. Therefore, in such a case, it is difficult to completely integrate the hollow molded product body 2 (the hardened parison 2) and the bracket 1, and the bracket 1 is likely to fall off from the body 2. Furthermore, when integrating by heat fusion, there are restrictions such as the need to select a material for the bracket 1 that has a lower melting temperature than the material for the parison 2. In addition, when a hollow molded product with such an additional bracket 1 is installed in a part of an automobile or the like that experiences strong vibrations, the bracket 1 tends to fall off from the hollow molded product main body 2 due to the long-term vibration. ing.

Purpose The present invention has been devised in view of the above points, and is capable of firmly fixing a hollow molded product and an additional part together without coming apart due to long-term vibration, etc.
Another object of the present invention is to provide a method for manufacturing a hollow molded product with additional parts, which eliminates restrictions on materials and time and effort such as surface treatment, and can improve production rates.

Configuration Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Although the additional part can take various shapes, in this embodiment, a case will be described in which the locking part is an approximately arch-shaped additional part. As shown in FIGS. 2a and 2b, the additional part 3 in this embodiment has an arch-shaped locking part 3a and a base part 3b, and an internal space 3c is formed between them. Although the locking portion 3a does not necessarily have to be arch-shaped as in this embodiment, it has a portion extending approximately parallel to the base portion 3b, and an internal space 3c is formed between the locking portion 3a and the base portion 3b. It is necessary that a portion of the parison forming the hollow molding be filled so that the parallel extending portions of the locking portion are held within the hollow molding. The base 3b has an internal space 3c.
In this example, two communication holes 3d are provided to communicate the external space 4 with the external space 4. In this case, the communication hole 3d is
As described later, when the internal space 3c is covered by the expanding parison and gradually compressed, the internal space 3c
It is best to install an appropriate number of them in positions where the gas inside can be efficiently exhausted. Further, as the material for the additional part 3, not only various thermoplastic resins but also metals can be used.

Next, as shown in FIG. 3, this additional part 3 is set in a predetermined position in the mold 5. In this case, an exhaust hole 5d is provided at a predetermined position to communicate the molding space 5a with the outside (atmosphere) and exhaust the air in the molding space 5a. Therefore, the locking part 3a and the internal space 3c of the additional part 3 are made to protrude into the molding space 5a, and the additional part 3 is set in the mold 5.
The respective communication holes 3d and exhaust holes 5d are provided so that the internal space 3c of the additional part 3 is directly communicated with the outside (atmosphere).
Align. Then, the parison 6 is housed in the molding space of the mold 5 and the mold is clamped.

Next, pressurized gas is blown into the parison 6 to perform blow molding. In this case, at the beginning of the pressurized gas injection, as shown in FIG. It is transformed. Then, as the pressure of the pressurized gas inside the parison 6 is gradually increased, the walls 6a and 6a' of the parison 6, which cover the internal space 3c of the additional part 3 and face each other via this space 3c, gradually become space 3c
is pressed inward. At this time, the internal space 3c is compressed by the incoming walls 6a and 6a', but
Since the internal space 3c is in communication with the atmosphere, its pressure is always atmospheric pressure and does not increase.
A' can enter the interior space 3c without much resistance. Eventually, the two wall portions 6a, 6a' abut and become integrated within the interior space 3c, as shown in FIGS. 4a and 4b. That is, the locking part 3 of the additional part
a is surrounded by walls 6a and 6a' of the parison, and finally the parison 6 is filled into the interior space 3c. In this way, the additional parts 3 are added to the parison 6.
Because the locking part 3a is completely added,
Since the additional part 3 does not fall off from the hollow molded product main body 6 unless the material filled in the internal space 3c is destroyed, the additional part 3 can be firmly and reliably fixed to the hollow molded product 6. Further, there is no need to perform surface treatment such as removing a mold release agent on each contact surface to maintain the structure, and furthermore, restrictions on the melting point of the material are eliminated, which is advantageous in terms of production. When the injection of pressurized gas is completed, the mold is opened, the mold is released, and then cooled and cured to obtain a hollow molded product with integrated additional parts.

Next, another embodiment of the present invention will be described.
This embodiment differs from the previous embodiment in that the shape of the additional parts is changed, and the rest is the same as the previous embodiment. As shown in FIG. 5a, the additional part 7 has a cylindrical internal space 7c between the locking part 7a and the base 7b, and the base 7b has a communication hole so as to communicate with the cylindrical internal space 7c. 7d is drilled. If the additional part 7 having such a shape is set in the mold as in the previous embodiment, then the parison is placed in the mold and pressurized gas is blown into the mold, as shown in Figures 6a and 6b. The parison 6 enters and fills the cylindrical space of the additional part 7, and the parison 6 is further attached to the additional part 7, so that the additional part 7 is integrally fixed to the main body 6. Moreover, as shown in FIGS. 7a and 7b, a plurality of cylindrical internal spaces 8c, 8d, and 8e are arranged in parallel between the locking part 8a and the base part 8b, and correspond to the respective internal spaces 8c, 8d, and 8e. It is also possible to provide a configuration in which communicating holes 8f and 8h are bored in the base 8b. If such an additional part 8 is used and manufactured in the same manner as in the previous embodiment, the additional part 8 will be integrally added to the hollow molded product main body 6 and will be firmly fixed, as shown in FIGS. 8a and 8b. will be established.

Effects Based on the manufacturing method of the present invention as detailed above,
It is possible to easily manufacture a hollow molded product substantially integrally using a blow molding method, in which additional parts are firmly fixed so that they will not fall off from the hollow molded product due to long-term vibrations, etc. Furthermore, pre-treatments such as removal of a mold release agent and residual heat are not required, and material restrictions regarding melting temperature are also eliminated, which is extremely advantageous in terms of productivity. Therefore, it is possible to inexpensively manufacture a hollow molded product in which additional parts are firmly and stably fixed by blow molding.

It should be noted that the present invention should not be limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention. In particular, the shape of the additional part can be various shapes, for example, cantilevered as shown in FIGS. 9a and 9b.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional blow molded product having additional parts, and FIGS.
A front view and a side cross-sectional view showing the additional part 3 in the embodiment, FIG. 3 is an explanatory view showing the state in which the additional part is set in the mold and the parison is stored, and FIGS. 4a and 4b are respectively shown in this figure. FIGS. 5a and 5b are a front sectional view and a side sectional view showing one embodiment of the invention, respectively, and FIGS. Figures a and 6b are a front sectional view and a side sectional view showing other embodiments of the present invention, and Figure 7a is a
7b are a front view and a side sectional view showing an additional part 8 of still another embodiment of the present invention, and FIG. 8a,
FIG. 8b is a front sectional view showing yet another embodiment of the present invention, and FIGS. 9a and 9b are a front sectional view and a side sectional view, respectively, showing still another embodiment. (Explanation of symbols), 3, 7, 8, 9: Additional parts,
5: Molding mold, 6: Parison (hollow molded product body),
3d, 7d, 8f, 8g, 8h, 9d: communicating holes.

Claims (1)

[Claims] 1 An additional part having a base and a locking part, the locking part having a part extending substantially parallel to the base and forming an internal space between it and the base. When the additional part is integrated with a blow molded product, a communication hole communicating with the internal space is provided in the base, and gas in the internal space is automatically discharged to the outside during blow molding. A method for producing a hollow molded product with additional parts, characterized by: