JPH0431290B2 - - Google Patents

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.

Conventional technology: Japanese Patent Application Laid-open No. 49 (1973) as a manufacturing method for the hollow body with built-in ribs
There is one shown in the -88957 publication. In this conventional example, two opposed synthetic resin base materials such as heated and softened sheets or hollow parisons are held between molds, and a protruding tool provided on this mold that can move forward and backward is used to form the above-mentioned material. By causing a portion of the synthetic resin base material to protrude from the outside to the inside, this protrusion forms a rib within the hollow body.

Problems to be Solved by the Invention In the conventional example described above, ribs can only be formed in the clamping direction (horizontal direction) of the mold, and ribs in the vertical direction cannot be formed. Therefore, it has not been possible to manufacture a hollow body with high bending rigidity using conventional manufacturing methods. Furthermore, rigidity in the direction perpendicular to the ribs (vertical direction) could not be expected. In addition, if the distance between both side walls of the hollow body is relatively large, the tips of the protrusions protruding from both sides may not come into contact with each other due to displacement due to the vertical play of the protrusions, and the ribs from the left and right may become misaligned. Or, there were cases where they were not molded in one piece.

Means and Effects for Solving the Problems The present invention was conceived in view of the above, 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 There is no problem in terms of strength even if the abutment of opposing protrusions deviates because they are relatively far apart, and the thickness of both sides and vertical ribs can be changed as necessary, increasing the strength of the molded product. The purpose of the present invention is to provide a method for manufacturing a hollow body with a built-in rib that can be changed according to the applied load. Three sheets are placed at intervals between opposing molds, and after the molds are clamped, a protruding tool is advanced in opposite directions from the inside of the cavity to bring a portion of the sheets on both sides into contact with the middle sheet, and then the sheets are ejected. After retracting the tool, pressurized fluid is blown between each sheet to form horizontal ribs from the contact area between the sheets on both sides and the intermediate sheet to the sheets on both sides,
The middle sheet forms vertical ribs. By the above means, in addition to the horizontal ribs, vertical ribs are formed by intermediate sheets inside the intermediate body, and the opposing horizontal ribs are integrally connected via the intermediate sheet. Furthermore, by changing the thickness of the three sheets, the thickness of the molded body can be partially changed.

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

In the figure, 1 shows three sheets 2a, 2 at equal intervals.
Sheet extrusion head that extrudes and hangs b, 2c, 3, 4
are left and right forming dies that are provided left and right opposite to the hanging center of the sheet extrusion head 1 and perpendicular to the respective sheets 2a, 2b, and 2c. Rectangular cavity 5,6
is provided. A plurality of plate-shaped protrusions 7, 8 are provided in both the molds 3, 4 so as to be able to move forward and backward into the cavities 5, 6, facing each other in the left and right molds 3, 4. . Each protruding tool 7, 8 in the left and right molds 3, 4 is
The connectors 9 and 10 are connected to each other on the outside by coupling tools 9 and 10, and are moved forward and backward as a unit by driving the coupling tools 9 and 10 with a cylinder device (not shown). In addition, each of the protrusions 7 and 8 is attached to the three sheets 2 from the same surface as the opposing bottom surfaces of the cavities 5 and 6.
The mutually opposing protrusions 7 and 8 move forward and backward over a range to the extent that the overlapping thickness of a, 2b, and 2c is slightly crushed. Reference numerals 11 and 12 indicate fluid injection nozzles provided in each cavity 5 and 6.

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

Three sheets 2a, 2 from the extrusion head 1 are placed between the left and right molds 3, 4 with the protruding tools 7, 8 retracted.
Extrude and hang b and 2c (Figures 1 and 2).

After mold clamping, the protrusions 7 and 8 are moved forward to deform a portion of the left and right sheets 2a and 2c inward and press their tips against the intermediate sheet 2b (third
Fig. 4). At this time, since the deformation of the left and right sheets 2a, 2c by the protruding tools 7, 8 is only a part of the central part in the width direction, both sides of this deformed part are between the mold-clamped left and right sheets 2a, 2c. The sheets 2b communicate with each other in the vertical direction.

In addition, in the mold clamping process, the left and right sheets 2
In order to maintain the space between a, 2c and the intermediate sheet 2b, the cavities 5, 6 of the left and right molds 3, 4 may be made to have negative pressure, if necessary. The negative pressure within the cavities 5 and 6 is maintained through suction holes (not shown) provided in the molds 3 and 4, through which the air within the cavities is sucked.

After retracting the protrusions 7 and 8, when pressure fluid is blown between the respective sheets, the left and right sheets 2a,
A horizontal rib 13 extends along the retreat path of the protrusions 7, 8 from the portion where the protrusions 7, 8 touch the intermediate sheet 2b, and extends from the portion where the protrusions 7, 8 touch the intermediate sheet 2b to the left and right sheets 2a, 2c.
14 is formed within the intermediate (FIGS. 5 and 6).

FIG. 7 shows a molded body manufactured by the above-mentioned manufacturing method, in which vertical ribs formed by the intermediate sheet 2b are formed in the vertical direction of the hollow space, and vertical ribs are integrally connected to the vertical ribs at multiple locations in the vertical direction. horizontal ribs 13, 14
are respectively molded, and therefore, this molded body can be oriented in the X direction (vertical direction), Y, Z direction (front and back, left and right directions)
It has great rigidity. An example of the use of this molded product is pallets used in cargo handling operations.

In the above embodiment, an example was shown in which the protrusions 7 and 8 were made into flat plates and moved forward and backward in a posture perpendicular to the longitudinal direction of the sheets 2a, 2b, and 2c, respectively. Both may be in a posture parallel to the longitudinal direction of the sheets 2a, 2b, 2c, or one may be in a posture orthogonal to the longitudinal direction, and the other may be in a posture parallel to the longitudinal direction.
Further, the cross-sectional shape of the protrusions 7 and 8 is not limited to a flat plate shape, but may be rod-shaped or cross-shaped.

Also, only the left and right sheets 2a and 2c are extruded from the extrusion head 1, and the intermediate sheet 2b is extruded from the left and right sheets 2a.
The sheets 2a and 2c may be extruded and then inserted between the sheets 2a and 2c. In this case, a hardened synthetic resin sheet is used as the intermediate sheet 2b, but it is preferably of the same quality as the left and right sheets 2a, 2b.

Furthermore, each of the three sheets 2a, 2b, and 2c may be formed by softening a material that has been previously formed into a plate shape.

Effects of the Invention According to the present invention, since vertical ribs can be formed in addition to the horizontal ribs 13 and 14, a hollow body having rigidity against bending in three-dimensional directions can be manufactured.

In addition, since the side walls that have been deformed inward to form the horizontal ribs 13 and 14 come into contact with the vertical ribs in the center of the parison 2, even if the protrusions 7 and 8 are slightly shifted on the opposing left and right sides, both sides The ribs 13 and 14 are integrally welded via vertical ribs, so even if the outer walls of the hollow body are relatively far apart and the opposing protrusions 7 and 8 come out of contact, the strength will not deteriorate. There is no danger.

Furthermore, according to the invention, three sheets 2a, 2
By changing the wall thicknesses of b and 2c, it is possible to thicken one side of a molded product, such as a pallet, and increase the strength of the part on which a large load is applied. Similarly, the materials of each sheet 2a, 2b, 2c can also be changed.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a vertical sectional view showing the state before mold clamping, and FIG.
A sectional view along the - line in the figure, Figure 3 shows the mold clamped,
4 is a sectional view taken along the - line in FIG. 3, FIG. 5 is a longitudinal sectional view showing the completed molding state, and FIG. 6 is a longitudinal sectional view taken along the - line in FIG. 5.
A cross-sectional view taken along the line, and FIG. 7 is a partially cutaway perspective view of the molded body. 2a, 2b, 2c are sheets, 3, 4 are molds,
5 and 6 are cavities, 7 and 8 are protrusions, 13 and 1
4 is horizontal rib.

Claims (1)

[Claims] 1. Three sheets 2a, 2b, 2c with at least the sheets 2a, 2c on both sides softened are arranged at intervals between the opposing molds 3, 4, and after clamping,
Protruding tools 7 in opposite directions from the inner surfaces of cavities 5 and 6;
8 is advanced to bring a portion of the sheets 2a, 2c on both sides into contact with the intermediate sheets 2a, 2c, then the protrusions 7, 8 are moved back, and each sheet 2a, 2b, 2 is moved forward.
Pressure fluid is blown between the sheets 2a and 2 on both sides.
A hollow body with built-in ribs is formed in which horizontal ribs 13 and 14 are formed from the abutting part between c and the intermediate sheet 2b to the sheets 2a and 2c on both sides, and vertical ribs are formed in the intermediate sheet 2b. Production method.