JPH0576706U - Blow molding machine for flat parison - Google Patents

Abstract

(57) [Summary] [Purpose] Extruding while maintaining the flat shape of the parison. [Structure] Dice 22 provided on parison head 21
The opening 25 is provided with a core 25 for partitioning the slit 24 having a flat cross section with the inner wall of the opening so as to form the flat parison 31. The core 25 is provided with an extruded gas supply means 27 having an ejection port 26 formed along the longitudinal direction A of the flat shape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a flat parison blow molding machine for molding a parison having an oval cross section.

[0002]

[Prior Art]

 The present applicant has previously proposed a "blow molding machine for flat parisons" for molding flat parisons for producing flat hollow products such as panels and boards (Japanese Utility Model Publication No. 3-98018).

As shown in FIG. 5, according to this proposal, a parison head 1 is provided with a die 2 having an opening having a flat cross section (elliptical shape), and the parison head 1 is provided so as to be vertically movable. The lower end portion (mandrel) 4 of the core 3 has the same shape, the resin passage (resin reservoir) 5 and the slit 6 defined between them have an annular flat shape, and the plunger 8 is lowered by the ring cylinder 7. The resin is extruded to form a flat parison 9. Further, a resin passage 10 for guiding another type of resin is formed outside the resin passage 5 and communicates with the same slit 6. With this structure, it is possible to form a flat parison 9 with fewer burrs than in the conventional method where a parison is extruded into a flat mold by means of a slit with a perfect circular cross section. It has become possible to mold the parison 9 having multiple layers of resin components.

[0004]

[Problems to be solved by the device]

 By the way, in this kind of blow molding machine, the parison 9 is placed on the air flow (pre-blow) ejected from the air nozzle provided in the die 2 and extruded into the mold, and after closing the mold, the air is sent into the parison. It is crimped onto the mold surface with to obtain the desired product shape.

However, as shown in FIG. 6, since the conventional air nozzle 11 is provided at the position of the axial center (center) of the core 3, the air flow distribution in the parison 9 is not uniform in the longitudinal axis direction A 1. As a result, there are problems that the parison surface becomes wrinkled, and both side surface portions 12 are adhered at a position away from the center so that the flat shape cannot be maintained and a predetermined molded product cannot be obtained. It was

In view of the above circumstances, the present invention has been devised to provide a blow molding machine for a flat parison that can extrude while maintaining the flat shape of the parison.

[0007]

[Means for Solving the Problems]

 According to the present invention, a core for partitioning a slit having a flat cross section with the inner wall of the opening is provided in the opening of the die provided in the parison head to form a flat parison, and the core of the flat shape is formed on the core. An extruding gas supply means having an ejection port formed along the longitudinal axis direction is provided.

[0008]

[Action]

 With the above structure, the parison is extruded into a flat shape from the slit between the die and the core. The extruding gas supply means forms a curtain-like gas flow in the parison during this extruding and maintains the flat shape.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 and FIG. 2 show a first embodiment of a blow molding machine for flat parisons according to the present invention. In this blow molding machine, a core 25 is provided in an opening 23 of a die 22 provided in a parison head 21 so as to partition an elliptical slit 24 having a flat cross-section with an inner wall of the opening. In addition, the core 25 is provided with an extruding gas supply means 27 having an ejection port 26 formed along the longitudinal direction A of the flat shape.

A resin reservoir 29 communicating with a resin passage (not shown) is defined between the body 28 of the parison head 21 and the body of the core 25. The resin reservoir 29 is moved downward by the plunger 30. By moving, the resin is pressed to the slit 24 side, and the flat parison 31 is molded.

The extruded gas supply means 27 includes an air pipe 33 that extends through a central position of the core 25 and extends downward from a core lower end (mandrel) 32, and a T-shape connected to the lower end of the air pipe 33. And the horizontal portion 35 of the branch pipe 34 is attached so as to be aligned in the longitudinal axis direction A of the flat shape. The jet outlets 26 are formed in a staggered manner below the horizontal portion 35 of the branch pipe at appropriate intervals, and air (or warm air) a is sent from an air supply source (not shown) via the air pipe 33. As a result, a downward airflow is formed.

Next, the operation of this embodiment will be described.

When the core 25 is set at a predetermined position in the parison head 21 and the resin is supplied to the resin reservoir 29, the plunger 30 is lowered by driving a cylinder (not shown). By this downward movement, the resin in the resin reservoir 29 is sequentially extruded downward, and a parison 31 having an oval cross section corresponding to the shape of the slit 24 is ejected. Then, in parallel with this extrusion, the air a is sent from the air supply source and jetted from the jet port 25 of the horizontal portion 35 via the air pipe 33 and the branch pipe 34. As a result, a curtain-shaped air flow a corresponding to the arrangement of the ejection ports 26 is formed inside the parison 31, and the parison 31 is pushed on the air flow a to be extruded to maintain its flat shape. Be drunk

The parison extruded into a mold (not shown) is blown with air after the mold is closed and pressure-bonded to the inner surface of the mold, and after cooling, the mold is opened and taken out as a product. .

In this way, the air pipe 33 and the branch pipe 34 are provided in the core 25, and the air a is ejected from the ejection port 26 formed in the horizontal portion 35 of the branch pipe 34. Further, a uniform pre-blow (a) is obtained in the longitudinal axis direction A, the flat shape of the parison 31 is maintained, and wrinkles and side surface portions are prevented from adhering. That is, improvement in the yield and quality of the molded product is achieved.

The air pipe 33 may be fixed in the core 25, or may be formed to be movable up and down and appropriately lowered in accordance with pushing.

3 and 4 show a second embodiment of the present invention, in which a plurality of air holes 44 are provided in the lower end portion 43 of the core 42 as the extruding gas supply means 41, and the lower end opening thereof is performed. The mouth is formed as the ejection port 45. The air holes 44 are arranged in parallel along the longitudinal direction A of the flat shape and are connected to each other so that the amount of ejected air becomes equal. In this embodiment, three air pipes 46 are connected to an air supply source (not shown), but if the air a can be uniformly ejected from the ejection ports 45, only one air pipe may be provided in the center. Good.

With this configuration, the air a supplied to each air hole 44 is ejected according to the arrangement inside the parison 31 extruded by the lowering of the plunger 30, and a curtain-shaped air flow is generated. By being formed, the flat shape of the parison 31 is maintained.

The other configurations and operational effects are the same as those of the first embodiment, and therefore will be omitted. Further, the core 42 having the air holes 45 may be provided with the branch pipe of the first embodiment so that the air a is ejected in two stages.

In the above embodiments, the structure in which the parison is molded with a single resin has been shown. However, the present invention provides a blow molding machine in which a plurality of resin passages are provided to mold a multi-layer resin parison. Is similarly applied.

[0022]

EFFECT OF THE INVENTION In summary, according to the present invention, the following excellent effects are exhibited.

Since the extruded gas supply means having the ejection port formed along the longitudinal direction of the flat shape is provided in the core provided to form the flat parison, the parison having the flat shape is extruded. It is possible to mold a product having a good flat shape.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of a blow molding machine for flat parisons according to the present invention.

FIG. 2 is a bottom view of FIG.

FIG. 3 is a side sectional view showing a second embodiment of the present invention.

FIG. 4 is a bottom view of FIG.

FIG. 5 is a side sectional view showing a conventional blow molding machine for flat parisons.

FIG. 6 is a bottom view for explaining the problems of the conventional technique.

[Explanation of symbols]

 21 Parison Head 22 Die 23 Opening 24 Slit 25 Core 26 Jet Port 27 Extrusion Gas Supply Means 31 Parison

Claims (1)

[Scope of utility model registration request] 1. A core for partitioning a slit having a flat cross section with an inner wall of the opening is formed in an opening of a die provided in a parison head so as to form a flat parison, and the core is provided with the above-mentioned core. A blow molding machine for flat parisons, characterized in that extrusion gas supply means having a jet port formed along the longitudinal axis of the flat shape is provided.