JPH0631086B2 - Frame hollow molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a frame-shaped hollow molded article made of thermoplastic plastic.

2. Description of the Related Art FIG. 15 shows an example of the above-mentioned frame-shaped hollow molded product, and the conventional molding of such a frame-shaped hollow molded product is as shown in FIG. The parison d is clamped by the two divided dies b and c in the vertical direction, and the parison d is placed in the space formed by the frame-shaped cavities b ₁ and c _{1 of} the respective divided dies b and c. Is formed by flow molding, and the pinch-off by both molds b and c is performed in the middle of the inner and outer surfaces along the frame shape, as shown in FIG. The pinch-off part g appeared in the middle part of the molded product a.

Problems to be Solved by the Invention In the case of blow molding, as shown in FIG. 16, the thickness of the pinch-off portion is thick and becomes thinner according to the blow ratio as the distance from the pinch-off portion increases. In particular, in the case of a frame-shaped hollow molded product, the corners e and f may become extremely thin, and when the blow ratio is large, the strength and rigidity of these corners decrease and the molded product cannot be used. May be.

Means and Actions for Solving Problems The present invention has been conceived in view of the above, and it is possible to improve the strength by eliminating the extremely thin portion due to the low blow ratio, and the pinch-off portion where the thickness becomes thick. The present invention is intended to provide a frame-shaped hollow molded product capable of improving rigidity because it intersects with the inner and outer surfaces of the frame body. In a frame-shaped hollow molded article formed in a frame shape having front and rear side walls that close both end sides of the wall, a linear pinch-off portion is provided on each inner side wall of the outer side wall, and at least one of them is inclined. The pinch-off portions are provided so as to relatively intersect with each other on the outer wall and the inner wall, and the thick portion formed by both pinch-off portions intersects the outer wall and the inner wall.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 14.

FIG. 1 shows a frame-shaped hollow molded product according to the present invention. The molded product 1 includes an outer wall 2 and an inner wall 3 facing each other and a front side wall 4 closing both ends of the both walls 2, 3. And a back side wall 5 in a rectangular frame shape. Then, one side portion in the thickness direction on one of the opposite sides of the molded product 1 has the pinch-off portions P ₁ and P _{1 at} the inner corner of the frame, and the other side portion has the pinch-off portion P _{2 at} the outer corner of the sum. , P ₂ are provided.

The other in opposing sides, outer wall 2 and the inner picture wall 3 of the pinch off portion P ₃ in a shape crossing each other inclined _{respectively,} P
₄ are provided. The pinch-off portions P ₃ and P ₄ of the both walls 2 and ₃ are connected to the pinch-off portions P ₁ , P ₁ , P ₂ and P ₂ provided on the one opposing side.

With the above configuration, the pinch-off portion relatively crosses the outer wall 2 and the internal wall 3 on the other opposing side, which reduces the blow ratio of the parison on each of the opposing sides, resulting in an extreme. No thin portion will occur. This is because the pinch-off portion is the starting point, and the Parish expands on the principle that the pinch-off portions relatively intersect,
This is because the defects of blow moldability are complemented by both walls.

2 to 14 show an embodiment of a molding die apparatus and a molding method for molding the molded product 1.

In the figure, 10 and 11 are left and right dies that are arranged opposite to each other on both the left and right sides of the parison 12, and frame-shaped cavities 13 and 14 are formed on these dies 10 and 11. The cavities 13 and 14 of both molds are bilaterally symmetrical in their front shapes.

First, the left mold 10 will be described with reference to FIGS. 2, 4, and 6.

The outer pinch-off portion 15 of the cavity 13 has upper and lower U-shaped high pinch-off sides A ₁ and A ₁ , left and right low pinch-off sides A ₂ and A _2, and diagonal pinch-off sides A ₃ and A that connect these. _It consists of ₃ . The pinch-off portion 16 inside the cavity 13 has upper and lower U-shaped lower pinch-off sides A ₄ and A ₄ and left and right higher pinch-off sides A ₅ and A ₅ and an oblique pinch-off side A ₆ that connects them. , and _{A 6} Tokara summer. On the outside of the outer pinch-off portion 15, a relief portion 17 for releasing the parison is provided over the entire circumference thereof. The inner pinch-off section 1
Similarly, an escape portion 18 for escaping the parison is provided inside 6.

Next, the metal 11 on the right side will be described with reference to FIGS. 3, 5, and 7.

_{'And 1,} the left and right high pinch-off sides _A' outside the pinch-off portion 15 'is lower pinch-off sides _A has decreased to and below the U-shaped' 1, A of cavity 14 and 2, A _'2, pinch-off of the diagonal connecting these It is composed of sides A ′ ₃ and A ′ ₃ .
The inside of the pinch-off portion 16 of the cavity 14 'is higher pinch-off side A has decreased to and below the U-shaped' _{4, A} '
₄ and left and right lower pinch-off edges _{A '5, A'} 5, are oblique pinch-off edges connecting these _{A '6, A'} 6 Tokara summer. And the outer and inner pinch-off portions 1
Similar to the mold 10 on the left side, parison escape portions 17 'and 18' are provided at 5'and 16 '.

A nozzle hole 19 for a blowing nozzle is provided in one of the molds 10 and 11.

The left and right molds 10 and 11 configured as described above are opposed to the left and right of the parison 20 (FIG. 10), and then the mold is clamped (FIG. 11), and then the pressure fluid is blown into the parison by the blowing nozzle 21. By blowing, a molded product as shown in FIG. 1 is obtained.

At this time, the pinch-off sides of both molds 10 and 11 are A ₁
And A _'1 are, A _{2, A'} becomes the pinch off portion in contact each pinch sides together represented by Yes and No Datsushiyu the same reference numerals as of _2.

FIGS. 12 to 14 show another embodiment of the molded product. In the one shown in FIG. 12, the pinch-off portions P ₁₃ and P ₁₄ are formed in a fold line shape inside and outside the frame body at one place. FIG. 13 shows an example of crossing, which is a linear pinch-off portion.
The P _23, P ₂₄ is an example in which cross at one point. Further, in the example shown in FIG. 14, the inner pinch-off portion P ₃₃ of the frame body is made parallel to the outer surface and the outer pinch-off portion P ₃₄ is formed into a polygonal line shape.
An example of crossing at points is shown.

EFFECTS OF THE INVENTION According to the present invention, the blow ratio between the outer side wall 2 and the inner side wall 3 facing and separated from each other is lowered, and the extremely thin portion is eliminated, so that the strength can be improved. Further, since the pinch-off portions whose thickness becomes thicker intersect each other on the outer wall 2 and the inner wall 2 which face each other, rigidity is also improved.

[Brief description of drawings]

1 to 14 show an embodiment of the present invention. FIG. 1 is a perspective view of a molded product, FIGS. 2 and 3 are front views of left and right molds, and FIG. 2 is a sectional view taken along line IV-IV in FIG. 5, FIG. 5 is a sectional view taken along line VV in FIG. 3, and FIG. 6 is a sectional view taken along line VI-VI in FIG. Is VI in Figure 3
Sectional views taken along line I-VII, FIGS. 8 and 9 are perspective views of the left and right molds, FIG. 10 is a front view showing a state before mold clamping, and FIG. 11 is a state after mold clamping. Sectional view showing No. 12
FIGS. 13, 13 and 14 are side views showing another embodiment of the molded product, FIG. 15 is a perspective view of the molded product of the conventional example, and FIG. 16 is a sectional view showing the molded state of the conventional molded product. Is. 1 is a molded product.

Claims (1)

[Claims] 1. A frame-shaped hollow molded article formed in a frame shape having an outer wall and an inner wall facing each other, and a front side wall and a back side wall closing both ends of the both walls. At least one of the linear pinch-off portions is provided at a slant in each of the two, and the two pinch-off portions are arranged so as to relatively intersect each other on the outer wall and the inner wall. .