JPH0434010Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a blow molding machine, and particularly to a blow molding machine that performs molding after expanding a parison, which is a molding material.

[Prior art and its problems]

Generally, with a direct blow molding machine, a cylindrical parison (with different diameters depending on the shape of the product) that is continuously extruded by an extruder is sandwiched between molds, and the inside of the parison is Air is blown into the parison to expand it and match the shape of the outer mold to form a molded product.

However, in the case of the above-mentioned products, the inner shape and precision of the molded product are determined by blowing air, so the problem is that the precision of the inner shape and dimensions of the molded product is very poor. It had

In other words, when a constant velocity joint boot is molded using a conventional blow molding machine, the parison is continuously extruded, and the parts other than the top part hang downward, so air is not absorbed during expansion. Therefore, when the boot for the constant velocity joint that has been molded for this purpose is attached to the constant velocity joint, it will be expanded by air and pressed against the outer mold. There was a problem in that the inner shape and dimensional accuracy of the clamp part was poor, resulting in poor sealing performance.

This idea solves the above-mentioned problems of the conventional method. Before the parison is blow-molded, a part of the parison is held between the molds to improve the inner shape and dimensional accuracy of the molded product. The purpose of the present invention is to provide a blow molding machine that can be improved.

[Means for solving problems]

In order to solve the above problems, this invention is capable of expanding and contracting, and has a molding surface that matches the external shape of the molded product, an upper middle mold, and a case located outside the mandrel. The case is movable by a drive source in a direction perpendicular to the moving direction of the outer mold so as to be able to come into contact with and separate from the upper middle mold, and a plurality of casings are provided on the lower surface of the upper middle mold at predetermined intervals. The upper end of the expansion plate is pivotally connected, and each expansion plate is provided with an interlocking mechanism so that it can be expanded when approaching the upper middle size of the case,
A means for disposing a lower middle mold movable in the same direction as the case by a driving source on the outside of the case, and further having an air blowing hole in the upper middle mold facing the outer surface of the expansion plate. This is what was adopted.

[Effect]

As mentioned above, this invention has a molding surface that matches the outer shape of the molded product, and is provided with an upper middle mold and a case located outside the mandrel inside an expandable and contractible outer mold. The case is movable in a direction perpendicular to the direction of movement of the outer mold, and the upper ends of a plurality of expansion plates are pivotally connected to the lower surface of the upper middle mold at predetermined intervals, and each expansion plate is provided with a portion of the case. The upper ends of the connecting rods pivotally connected to the upper part are each pivoted so that the case can be expanded when approaching the upper middle part, and a lower middle part is disposed outside the case and is movable in the same direction as the case. Furthermore, by providing an air blowing hole facing the outer surface of the expansion plate in the upper middle mold, the case can be approached to the upper middle mold after the parison is positioned between the upper middle mold and the outside of the case. Then, the lower end of the parison is expanded outward via the expansion plate by the connecting rod, and is located outside of the lower middle mold, moves the lower middle mold to be located inside the parison, and then expands the outer mold. The parison is contracted and closed, and the air blown from the air blowing hole is blown inside the parison, so that the parison is blow-molded into a shape that matches the outer mold.

〔Example〕

Embodiments of this invention shown in the drawings will be described below.

FIG. 1 shows the main parts of a blow molding machine according to this invention. Reference numeral 1 is a cylindrical parison, and a mandrel 3 is provided inside the parison 1.

Then, an O-ring 1 is attached to the lower end of the mandrel 3.
1 and a bush 10, a case 9 is provided so as to be movable by a drive source (not shown).
A lower middle mold 5 is provided on the outside of the mandrel 3 and is movable in the same direction as the case 9 by a drive source (not shown) via an O-ring 12. An upper middle mold 4 is provided with an air blowing hole 6 for blowing air to the outside.

A plurality of expansion plates 7, 7... are pivotally attached to the lower end of the upper medium 4 at predetermined intervals,
Further, the upper ends of the connecting rods 8, 8... constituting the interlocking mechanism are pivotally attached to the lower surfaces of the central parts of the expansion plates 7, 7..., and the lower ends of the connecting rods 8, 8... They are each pivotally attached to the upper end of the case 9.

Therefore, the combination of the expansion plate 7 and the connecting rod 8 configured as described above is the upper middle size 4.
and case 9 with a predetermined interval between them.
As shown in the figure, multiple sets are provided.

Further, on the outside of the parison 1, an outer mold 2 having a molding surface that matches the outer shape of the molded product is provided so as to be expandable and contractable.

Therefore, first, when the parison 1 is lowered to the state shown in FIG. 1, the case 9 is moved by a drive source (not shown) such as an air cylinder or a motor.
rises, and at this time, the upper middle mold 4 does not move, so the distance between the upper middle mold 4 and the case 9 becomes narrower.
For this purpose, the expansion plate 7 is
expands the parison 1 outward by using the pivoting end with the upper middle mold 4 as a fulcrum.

Then, when the inner diameter of the parison 1 becomes larger than the outer diameter of the lower middle mold 5, an air cylinder,
The lower middle mold 5 is raised to the state shown in FIG. 2 by a drive source (not shown) such as a motor.

In this state, that is, with the lower middle mold 5 located inside the parison 1, the case 9
is lowered to contract the expansion plate 7 inwardly via the connecting rod 8, and the outer mold 2 is moved in the direction of arrow A to close the outer mold 2.

At this time, both ends of the parison 1 are located between the middle molds 4 and 5 and the outer mold 2, and in particular, the lower end of the parison 1 is located between the outer mold 2 and the lower middle mold 5. Since this portion becomes the wide mouth portion of the constant velocity joint, the inner diameter shape and dimensions of this portion are regulated by the lower middle die 5.

After that, air is blown into the inside of the parison 1 from the air blowing hole 6 formed in the upper middle mold 4, and the parison 1 is pressed against the outer mold 2 to match the shape of the molding surface of the outer mold 2. Blow molding is performed.

In the above embodiment, the connecting rod 8 is used as an interlocking mechanism for moving each expansion plate 7 outward when the case 9 is raised. Any configuration may be used as long as the expansion plate 7 is expanded to occasionally expand the parison 1 outward.

[Effect of idea]

As described above, this invention includes an upper middle mold and a case located outside the mandrel inside an outer mold that is expandable and contractible and has a molding surface that matches the outer shape of the molded product. The case is movable by a drive source in a direction perpendicular to the moving direction of the outer mold so as to be able to move toward and away from the upper middle mold, and the upper ends of a plurality of expansion plates are arranged at predetermined intervals on the lower surface of the upper middle mold. As well as providing an interlocking mechanism between each expansion plate and the case,
Each expansion plate expands and contracts as the case approaches and separates from the upper middle mold, and a lower middle mold movable in the same direction as the case by a drive source is disposed outside the case, and By providing air blow holes facing the outer surface of the expansion plate in the upper middle mold, the end of the parison can be positioned between the upper middle mold and the outer mold and between the lower middle mold and the outer mold. Since air is blown inside the parison, blow molding is ensured, and the inside shape and dimensions of the opening are regulated by the medium mold, which significantly improves the molding accuracy of the molded product. It has excellent effects such as:

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the main parts of the blow molding machine according to this invention, FIG. 2 is a schematic diagram showing the operating state, and FIG. 3 is a view taken in the direction of arrow A in FIG. 1... Parison, 2... Outer mold, 3... Mandrel, 4, 5... Medium size, 6... Air blow hole, 7...
...Expansion plate, 8...Connecting rod, 9...Case, 10...
...Butsuyu, 11, 12...O-ring.

Claims (1)

[Claims for Utility Model Registration] (1) The upper middle mold 4 and the mandrel 3 are located inside the outer mold 2 which is expandable and contractible and has a molding surface that matches the outer shape of the molded product. A case 9 is provided, and the case 9 is movable by a drive source in a direction perpendicular to the moving direction of the outer mold 2 so as to be able to come into contact with and separate from the upper middle mold 4. The upper ends of a plurality of expansion plates 7 are pivotally connected at intervals of A lower middle mold 5 movable in the same direction as the case 9 by a drive source is disposed, and the upper middle mold 4 is further provided with the expansion plate 7.
After the parison 1 is positioned outside the upper middle mold 4, each expansion plate 7, and the case 9, the case 9 is brought close to the upper middle mold 4, and The parison 1 is expanded by expanding the plate 7, and then the lower middle mold 5 is moved to be located inside the parison 1, and the outer mold 2 is reduced, and then air is injected from the air blowing hole 6. A blow molding machine characterized by blow molding. (2) The interlocking mechanism of the expansion plate includes a connecting rod 8 whose upper end is pivotally attached to the lower surface of the central part of the expansion plate 7 and whose lower end is pivotally attached to the upper surface of the case 9,
The blow molding machine according to claim 1, wherein the expansion plate 7 is expandable when the case 9 is moved.