JPS633782Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for extrusion molding a net-like body using polyolefin-based or other thermoplastic synthetic resin.

For example, a net-like body A such as an underdrain drain pipe shown in FIG. 6 is constituted by a synthetic resin molded body formed by integrally molding warp threads _a1 and weft threads _a2 in a lattice shape. In such a reticular body A, for example, as shown in _FIG . Preferable for increasing strength (including earth pressure resistance). In addition, the fact that the inner circumferential surfaces of the warp threads a ₁ and weft threads a ₂ are smooth surfaces (with a small roughness coefficient) located on almost the same virtual cylindrical surface allows water that has entered inside to be quickly drained. It is preferable to do so. moreover,
When using net-like body A as an underdrain drainage pipe, in order to increase the ability to conduct water to the internal passage, it is possible to increase the opening ratio of the wall surface as much as possible without reducing the above-mentioned earth pressure resistance strength and high drainage performance. It is desirable to make it larger.

The purpose of the present invention is to provide an extrusion molding device that can effectively and continuously mold a net-like body such as an underdrain drain pipe that satisfies the various characteristics described above. An explanation will be given according to an example.

In FIG. 1, reference numeral 1 denotes a movable die that is reciprocated up and down, and has a stepped resin reservoir 11 at its lower end, and has a circular lower end outer periphery as it approaches its lower end, that is, its outer end. It has a tapered sealing surface 12 that is inclined to have a small diameter. As clearly shown in FIG. 2, on this sealing surface 12, a plurality of concave grooves 13 are arranged in parallel at equal angles to form extrusion passages for the warp thread _a1 (see FIG. 6). has been done. Furthermore, an inner surface regulating member 2 is provided on the lower end surface of the movable die 1 to form an inner surface of the warp threads to be extruded through the warp thread extrusion passage in the groove 13.
is provided. That is, this inner surface regulating member 2
has a smooth cylindrical outer peripheral surface. On the other hand, a fixed die 3 is provided around the movable die 1, and an extrusion passage 4 for the molten synthetic resin is formed between the two dies 1 and 3. Also,
The fixed die 3 is provided with a tapered sealing surface 31 on the inner periphery of the lower end of a perfect circle, the diameter of which becomes smaller as it approaches the lower end, that is, the outer end. This sealing surface 31 has the same slope as the sealing surface 12 of the movable die 1 described above, and has the same slope as the sealing surface 12 of the movable die 1 described above.
When the movable die 1 is moved upward, an extrusion passage is formed for the weft yarn _A2 between the movable die 1 and the sealing surface 12 of the movable die 1, while when the movable die 1 is moved downward and the sealing surface 12 of the movable die 1 comes into contact with the The extrusion passage of the weft yarn _a2 is blocked (see Figure 3). When the extrusion passage for the weft yarn a ₂ is opened by the upward movement of the movable die 1, the inner surface of the weft yarn a ₂ extruded through the extrusion passage is controlled by the inner surface regulating member 2 to It is designed to be molded flush with the inner surface of a ₁ (see Figure 3). Further, a tapered weft forming mold surface 5 which is inclined in a downwardly expanding manner is provided adjacent to and below the sealing surface 31. Further, in FIG. 1, reference numeral 6 indicates a molten synthetic resin extrusion tool, which is provided in a molten resin extrusion path 4 between the movable die 1 and the fixed die 3 so as to be movable up and down.

Next, the effect will be explained.

As shown in FIG.
When the molten synthetic resin P is pushed out through the extrusion passage 4 from the state in which the extrusion tool 6 is brought into contact with It passes through R ₁ and is formed into warp thread A ₁ . In this case, the inner surface of the warp thread _a1 is formed smoothly by the inner surface regulating member 2. Next, move the movable die 1 upward as shown by the arrow in the same figure to form a weft extrusion passage _R2 shown in FIG. 4 between its sealing surface 12 and the sealing surface 31 of the fixed die 3, When the extrusion tool 6 is moved downward in the direction of the arrow, the molten synthetic resin P passes through the weft extrusion passage R ₂ and is forced into the fixed die 3 all at once.
The weft yarn is pushed out to the side of the mold surface 5 for forming the weft yarn, and after passing through the state shown in FIG _.
is formed. In addition, the weft thread a ₂ formed in this way
The inner surface of the warp threads is
Formed into a smooth surface flush with a ₁ . After forming the weft yarn _A2 , the movable die 1 is moved downward as shown by the arrow D in the figure, and the extruder 6 is moved upward as shown by the arrow, thereby forming the warp yarn _A1 as explained in FIG. Move to. Thereafter, repeat the same operations as described above.

In this way, the warp threads _a1 and the weft threads _a2 having a triangular cross section are integrally formed in a lattice shape, like the mesh body A of the underdrain drain pipe, etc. explained in FIGS. 6 and 7, and A cylindrical mesh body with a smooth inner surface is continuously molded.

In the above case, when forming the weft yarn _{a 2} , as shown in FIG. I explained what makes it rise. However, as shown in FIG. Mold surface 7 that receives the lower surface of weft thread a ₂
1, this formwork 7 can be used when forming the weft thread _a2 .
There is an advantage in that the cross-sectional shape of the weft thread _a2 can be reliably made into a desired shape by causing the weft thread a2 to protrude at the position indicated by the imaginary line in the figure. Moreover, by adopting such a configuration, by simply changing the shapes of the mold surfaces 5, 71 to desired ones, it is possible to create a net-like body A having a trapezoidal cross-sectional weft thread _a2 as shown in FIG. A weft thread with a rectangular cross section like ₂
It becomes possible to easily extrude the reticular body A having the following properties.

As explained above, according to the present invention, the molten synthetic resin can be forcibly extruded when forming the weft threads of the net-like body, so weft threads with various cross-sectional shapes can be easily molded integrally with the warp threads. It becomes possible,
It can be suitably used in forming underdrain drainage pipes, etc., which require high earth pressure resistance. In this case, the inner surfaces of the warp and weft are formed into flat smooth surfaces by the inner surface regulating member, so that continuous extrusion molding of a net-like body with a smooth inner surface becomes possible. Another advantage is that the aperture ratio of the mesh can be set arbitrarily by simply changing the forming pitch of the weft threads.

In addition, in the above-mentioned example, a case where a cylindrical mesh body can be continuously extruded is explained, but the invention is not limited to this, and flat or corrugated mesh bodies can also be continuously extruded based on the same idea. Can be extruded.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of an embodiment of the present invention, Fig. 2 is a sectional view taken along the line 5 is a partial vertical sectional view of another embodiment, FIG. 6 is a schematic perspective view of the reticular body, FIG. 7 is an enlarged sectional view of the main part of FIG. 6, FIG. FIG. 9 is an enlarged sectional view of a main part showing different modified examples of the reticular body. A... Reticular body, a ₁ ... warp, a ₂ ... weft, P...
...Melted synthetic resin, R ₁ ...Warp extrusion passage, R ₂ ...
Weft extrusion passage, 1...Movable die, 12...Sealing surface of movable die, 13...Concave groove, 2...Inner surface regulating member, 3...Fixed die, 31...Sealing surface of fixed die, 4... Extrusion passage for molten synthetic resin, 6
...Extrusion tool.

Claims (1)

[Scope of utility model registration request] A pair of dies that form an extrusion passage for molten synthetic resin between them are each provided with a tapered sealing surface whose diameter decreases as it approaches the outer end,
One die is movable so that its sealing surface can come into contact with and separating from the sealing surface of the other die, and a warp extrusion passage is formed between the sealing surface of the movable die and the sealing surface of the other die. A plurality of concave grooves are provided, and when the sealing surface of the movable die is separated from the sealing surface of the other die, a weft extrusion passage is formed between both sealing surfaces, and the warp extrusion passage is The movable die is provided with an inner surface regulating member that forms the inner surfaces of the warp and weft threads extruded through the weft extrusion passage into a flush shape, and an extrusion tool is provided that forcibly extrudes the molten synthetic resin in the extrusion passage. Reticular body extrusion molding equipment.