JPS6274623A - Manufacture of hollow body with built-in rib - Google Patents

Abstract

PURPOSE:To manufacture a hollow body, which is rigid to three-dimensional bending, by a method wherein some portions of the side wall of a cylindrical parison, which has a vertical rib in the diametral direction, are abutted against the vertical rib by advancing ejectors in facing directions from the inner surfaces of the cavities of molding tools after the parison is extruded between the molds. CONSTITUTION:First, a parison 2, the cross-sectional shape of which is cylindrical and at the same time in the diametral direction of which a vertical rib 2a is provided, is hangingly extruded from a parison extruder head in between a left and a right molding tools 3 and 4 with protruding members 7 and 8 in retreated state. Secondly, after the molding tools are clamped, the protruding members 7 and 8 are advanced so as to deform some portions of the side wall of the parison 2 inwards in order to abut the tips of the deformed portions against the vertical rib 2a. Thirdly, after the protruding members 7 and 8 are retreated, pressure fluid is blown in the parison 2 in order to form lateral ribs 13 and 14 along the lines of retreat of the protruding members 7 and 8 within a hollow body.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a rib-embedded hollow body having ribs inside the hollow body.

Prior Art A method for manufacturing the above-mentioned hollow body with built-in ribs is disclosed in Japanese Patent Application Laid-open No. 49-88.
There is one shown in Publication No. 957.

In this conventional example, two opposing
A synthetic resin base material such as a sheet or a hollow parison is held between molds, and a part of the threatening resin base material is projected from the outside to the inside using a protruding tool provided on the mold that can move forward and backward. Additionally, this protrusion is used to form ribs within the hollow body.

Problems to be Solved by the Invention In the above conventional example, the mold clamping direction (lateral direction) of the mold
It is not possible to form vertical ribs. Therefore, it has not been possible to manufacture a hollow body with high rigidity against bending using conventional manufacturing methods.

Furthermore, rigidity in the direction perpendicular to the ribs (vertical direction) could not be expected. When the gap between both side walls of the hollow body is relatively large, the tips of the protrusions protruding from both sides do not abut properly due to displacement due to the vertical play of the protrusions, and the ribs from the left and right There were cases where the parts were misaligned or not molded together.

Means and Effects for Solving the Problems The present invention was conceived in view of the above-mentioned problems, and it is possible to manufacture a hollow body having rigidity against bending in three-dimensional directions, and the distance between the outer walls of the hollow body is The purpose of the present invention is to provide a method for manufacturing a hollow body with built-in ribs that does not cause problems in terms of strength even if opposing protrusions that are relatively far apart come into contact with each other, and to achieve this purpose. This means extrudes a parison having a cylindrical cross-sectional shape and longitudinal ribs in the diametrical direction between opposing molds, and after clamping the molds, advances a protruding tool from the inner surface of the cavity of the mold in the opposite direction. A part of the side wall of the parison is brought into contact with the vertical rib, and then the protruding tool is retreated, and then pressure fluid is blown into the parison to form a horizontal rib from the abutting part of the side wall and the vertical rib to the side wall. There is. By the above means, vertical ribs are formed in addition to the jet ribs inside the hollow body, and the opposing horizontal ribs are integrally connected via the vertical ribs.

Example Embodiments of the present invention will be described based on the drawings.

In the figure, 1 is a parison extrusion head that extrudes and hangs a parison 2 having a cylindrical cross-sectional shape and a vertical rib 2 cL in the diameter direction, and 3.4 is a parison extrusion head that extends left and right with respect to the barison hanging line of this parison extrusion head 1. Opposing and the above parison 2?
These are left and right molds provided in a direction perpendicular to the rib 2α, and a rectangular cavity 5.6 is provided on the opposing inner side of this image mold 3.4. Then, in the drawing mold 3.4 there is a plate-shaped protrusion 7.6 that can move forward and backward into the cavities 5 and 6.
A plurality of molds are provided in each of the left and right molds 3 and 4, facing each other.

The respective protruding tools 7.6 in the left and right molds 3.4 are connected by tying tools 9, 1o on the outside of the molds 3, 4,
These connectors 9 and 1o are moved forward and backward as one by driving them with a cylinder device (not shown). Each protrusion 7.8 of the cavity 5.6 extends from the opposite bottom surface of the cavity 5.6 to both side walls of the parison 2 and the vertical rib 2α.
The thick silkworms move forward and backward over a range to the extent that they are slightly crushed by the mutually opposing protrusions 7 and 6. 1
1.12 is a fluid injection nozzle provided in each cavity 5.6.

The manufacturing method according to the present invention will be explained below using the apparatus having the above configuration.

Protrusion - left and right molds 3 and 4 with X7 and 6 retracted
In the meantime, a parison 2 having a cylindrical cross-sectional shape and having vertical ribs 2α in the diameter direction is extruded from the parison extrusion head I and hangs down (FIG. 1).

Figure 2).

After clamping, the protrusions 7 and 6 are moved forward to deform a part of the side wall of the parison 2 into the inner II+, and press its tip against the vertical rib 2α (FIGS. 3 and 4).

At this time, since the side wall is deformed by the protrusions 7 and 8 only in a portion of the side wall, both sides of this deformed portion are connected in the vertical direction within the balison.

After retracting the protrusions A7 and 8, when pressure fluid is blown into the parison 2, the protrusions 7.
Along the retraction path of 8, transverse ribs 13,14 are formed within the hollow body (FIGS. 5 and 6).

FIG. 7 shows a next molded product manufactured by the above manufacturing method, with vertical ribs 2cL in the vertical direction in the hollow, and horizontal ribs 13 integrally connected to the vertical ribs 2 at multiple locations in the vertical direction. ．． +4 are respectively molded, so this molded body can be oriented in the X direction (vertical direction), Y, and Z directions (front and back, left and right directions).
It has great rigidity. An example of the use of this molded body is a pallet used for cargo handling work.

In the above embodiment, the protrusions 7 and 8 are shaped like flat plates and move forward and backward in a horizontal position perpendicular to the extrusion direction of the parison 2. However, the protrusions 7 and 6
Both may be in a vertical position parallel to the extrusion direction of the parison 2, or one may be in a horizontal position and the other may be in a vertical position. Further, the cross-sectional shape of the protrusion 7.8 is not limited to a flat plate shape, but may be rod-shaped or cross-shaped.

Effects of the Invention According to the present invention, in addition to the horizontal ribs 13 and 14, the vertical ribs 2α
By being able to mold the hollow body, it is possible to manufacture a hollow body that has rigidity against bleeding in three-dimensional directions.

As the horizontal ribs 13.14 are rounded and deformed inward, the horizontal ribs 13.14 are brought into contact with the vertical ribs 2α in the center of the parison 2. Both horizontal ribs 13° and vertical ribs 25I are integrally melted, so even if there is a relative distance between the outer walls of the hollow body and the opposing protrusions 7.60 come into contact with each other, the strength is maintained. There is no risk of a decline.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view showing the state before mold clamping, FIG. 2 is a sectional view taken along the π-TI line in FIG. 1, and FIG. 3 is a diagram showing the mold clamping state. 4 is a sectional view taken along the y-y line in FIG. 3, FIG. 5 is a longitudinal sectional view showing the completed molding state, and FIG. FIG. 7 is a sectional view taken along line WM in the figure, and FIG. 7 is a partially cutaway perspective view of the molded body. 2 is Harrison, 2α is vertical rib, 3.4 is mold, 5, 6
is the cavity, 7.8 is the protrusion, +3. +4tl'i horizontal rib.

Claims (1)

[Claims] A parison 2 having a cylindrical cross-sectional shape and having vertical ribs 2a in the diameter direction is extruded between opposing molds 3 and 4, and after clamping, the parison 2 is extruded from the inner surface of the cavities 5 and 6 of the molds 3 and 4. The protruding tools 7 and 8 are advanced in the direction to bring a part of the side wall of the parison 2 into contact with the vertical rib 2a, and then the protruding tools 7 and 8 are retreated, and pressure fluid is blown into the parison 2 so that the side wall and the vertical rib 2a are brought into contact with each other. The horizontal ribs 13, 1 extend from the abutting part to the side wall.
4. A method for manufacturing a hollow body with built-in ribs.