JP2003165152A - Blow-molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a flat blow-molded article having double walls from buckling by forming at least one row of reinforcing ribs to increase resistance against a vertical load and a shearing load. <P>SOLUTION: The first reinforcing ribs 14 and the second reinforcing ribs 15 which are arranged alternately and sequentially in the length direction of the row are provided. The first rib 14 is a part having an approximately trapezoidal cross section composed of both side parts 14a extending continuously from one wall 11 of the double walls toward the other wall 12 and a narrowed apex face part, and the apex face part is welded to the inside of the other wall 12. The second rib 15 is a part 15b extending continuously from one wall 11 of the double walls toward the other wall 12 with the whole of it including the apex part or most of it welded to each other to form the shape of a plate, and the apex part has a gap between it and the other wall 12. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat blow molded product having a double wall with ribs for reinforcement formed thereon.

[0002]

2. Description of the Related Art A rib connecting two walls is formed in order to reinforce a flat blow-molded body having a double wall. As a rib of this type, as shown in FIG. A rib 3 having a substantially trapezoidal cross-section composed of both side surface portions 3a continuously extending from 1 toward the other wall 2 and a narrowed top surface portion 3b, as shown in FIG. There is known a rib 4 which continuously extends from 1 toward the other wall 2 and is welded to each other to form a plate. The top surface portion 3b of the rib 3 is welded to the inner surface of the wall 2 during blow molding (see FIG. 9 (a)),
The top of the rib 4 is also welded to the inner surface of the wall 2 (see FIG. 10).
(See (a)) The double walls are connected in a row to reinforce.

[0003]

However, although the rib 3 having a trapezoidal cross section is strong against the load applied so as to bend the blow-molded body perpendicularly to the length direction of the rib 3, the blow-molded body is provided with the rib 3. For the load applied to bend along the length direction of, the rigidity is rather weaker than without ribs,
As shown in FIG. 9 (b), the opening side expands (narrows conversely when the load direction is opposite), and the entire blow-molded body is easily bent. Further, although the plate-shaped rib 4 is strong against a load applied perpendicularly to the wall surface of the blow-molded body,
As shown in (b), the rigidity is weak against a load (shear load) applied diagonally in the lateral direction, and buckling is likely to occur.

According to the present invention, when one row or a plurality of rows of reinforcing ribs are formed on a flat blow molded article having a double wall, conventional ribs having a trapezoidal cross section or a plate-shaped rib are formed. The purpose is to obtain a blow-molded body without problems.

[0005]

The blow-molded article according to the present invention is a flat blow-molded article having a double wall, in which one or more rows of reinforcing ribs are formed between the double walls. The ribs are composed of first ribs and second ribs alternately arranged in the length direction of the row and continuous in the length direction, the first ribs being continuous from one wall of the double wall to the other wall. It is a portion having a substantially trapezoidal cross section composed of both side surfaces extending toward each other and a narrowed top surface portion, and the top surface portion is welded to the inside of the other wall, and the second rib is provided on one side of the double wall. Characteristically characterized in that it extends continuously from the wall toward the other wall, and all or most of the part including the top is welded to each other to form a plate, and the top has a gap between the other wall. And In addition, the substantially trapezoidal cross section represents a shape when viewed in a cross section perpendicular to the length direction of the row.

Alternatively, one or more rows of reinforcing ribs are also formed between the double walls, and the ribs are alternately arranged in the length direction of the row and are continuous with the first ribs in the length direction. The first rib comprises a second rib, and the first rib has a pair of cross-sections each of which has a narrow top surface portion and both side surface portions that continuously extend from one wall and the other wall of the double wall toward the opposing wall. It is a trapezoidal shape, and each facing top surface is 2
The second ribs are welded to each other at an intermediate position of the double wall, and the second rib extends continuously from one wall and the other wall of the double wall toward the opposite wall, and includes all or most of the opposite tops. Is a plate-shaped portion that is welded to each other, and has a gap between the facing tops.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The blow-molded article according to the present invention will be specifically described below with reference to FIGS. Figure 1
The blow-molded body 10 shown in FIG.
Between 2), three ribs 13 for reinforcement are formed in parallel. The rib 13 includes a first rib 14 and a second rib 15,
The first ribs 14 and the second ribs 15 are alternately arranged in the lengthwise direction, and are continuously and integrally connected in the lengthwise direction via the transition portion 16. Also, when viewed in the adjacent rows, the first ribs 14 and the second ribs 15 are displaced in the length direction, and are in a so-called staggered arrangement.

As shown in FIG. 2 (a), the first rib 14 has both side surface portions 14a extending continuously from the wall 11 toward the wall 12 and a top narrower than the opening side (one wall 11 side). It is a portion having a substantially trapezoidal cross section formed of the surface portion 14 b, and the top surface portion 14 b is welded to the inside of the wall 12.
In addition, the second rib 15 is provided on the wall 1 as shown in FIG.
1 extends continuously toward the wall 12, and most of the portions including the top portion 15a are welded to each other to form a plate shape, and the plate portion 15b rides on the bottom portion having a substantially trapezoidal cross section 15c. Eggplant The top portion 15 a has a gap 17 with the wall 12.

A part of the mold 18 (the mold forming the cavity on the side of the wall 11) for forming the rib 13 (the first rib 14 and the second rib 15) between the double walls is shown in FIG. It is described in. On the cavity surface of the mold 18, three rows of protrusions 19 having a substantially trapezoidal cross section are formed. The protrusions 19 are composed of high protrusions 19a and low protrusions 19b which are alternately arranged along the length direction. Become. The first ribs 14 are formed by high protrusions 19a, and the second ribs 15 are formed by low protrusions 19a.
It is formed in part b. In the portion of the low protrusion 19b, the parison is stretched between the high protrusions 19a on both sides, and most of the parison is folded back without sticking to the low protrusion 19b. As shown, a plate-shaped portion 15b is formed. In the mold 18, the height of the low protrusion 19b can be zero (same height as the cavity surface forming the wall 11). In this case, the second rib 15 does not have the substantially trapezoidal section 15c on which the plate-shaped section 15b rides, but only the plate-shaped section 15b. Further, in this mold 18, when the protrusion 19 is not stepped (same height along the length direction), the blow molded body shown in FIG. 7 is formed.

In the blow-molded body 20 shown in FIG. 4, three reinforcing ribs 23 are similarly formed in parallel between the double walls (walls 21 and 22). The rib 23 is the first rib 2
4 and the second rib 25, the first rib 24 and the second rib 2
5 are alternately arranged in the length direction and are continuously connected in the length direction. The difference from the blow-molded body 10 is that three rows of central ribs extend from the wall 21 toward the wall 22 and
Only the ribs on both sides of the row extend from the wall 22 toward the wall 21.

In the blow-molded body 30 shown in FIG. 5, reinforcing ribs 33 are arranged in parallel between the double walls (walls 31 and 32).
Formed in rows. The rib 33 includes a first rib 34 and a second rib 35, the first rib 34 and the second rib 35 are alternately arranged in the length direction, and are continuously connected in the length direction via a transition portion 36. There is. As shown in FIG. 6A, the first rib 34 includes both side surface portions 34 a extending continuously from the wall 31 and the wall 32 toward the opposing wall, and the narrowed top surface portion 3.
4b, which are a pair of substantially trapezoidal sections in cross section, and the opposing top surface portions 34b, 34b are welded to each other at an intermediate position of the double wall. In addition, the second rib 35
As shown in FIG. 6 (b), the wall 31 and the wall 32 continuously extend toward the opposing walls, and most of the opposing tops 35 a, 35 a are welded to each other to form a plate shape. The plate-shaped portions 35b are respectively placed on the low-pitched portions 35c having a low cross section. Opposing tops 35a, 35a have a gap 37 between them.

[0012]

In the blow-molded product according to the present invention, the reinforcing ribs are formed in one row or a plurality of rows, and the ribs are composed of the first rib and the second rib of the above-mentioned form. The second rib provides a large resistance to a bending load in the direction of expanding or narrowing the opening side of the first rib, and the first rib provides a large resistance to a load (shear load) obliquely applied in the lateral direction. Therefore, resistance to bending load (bending rigidity)
Is strong in any direction, the resistance to shear load (shear rigidity) and the resistance to compression load (compression rigidity) are also strong,
Buckling is less likely to occur. Therefore, the blow molded product 10 according to the present invention is generally about 30 to 40% compared to the blow molded product of the type of FIG. 7 and 20 to 30% compared to the blow molded product of the type of FIG. The weight can be reduced. Therefore, it is suitable as, for example, an automobile spoiler, an OA floorboard, an automobile flooring material, a pallet, and the like.

[Brief description of drawings]

FIG. 1 is a perspective view of a blow molded body according to the present invention.

FIG. 2 is a cross-sectional view (a) of the first rib and a cross-sectional view (b) of the second rib taken along a plane perpendicular to the length direction of the rib.

FIG. 3 is a partial perspective view of the manufacturing die (one side).

FIG. 4 is a perspective view of another blow-molded article according to the present invention.

FIG. 5 is a perspective view of still another blow-molded article according to the present invention.

FIG. 6 is a cross-sectional view (a) of the first rib and a cross-sectional view (b) of the second rib in a plane perpendicular to the length direction of the rib.

FIG. 7 is a perspective view of a conventional blow-molded body.

FIG. 8 is a perspective view of another conventional blow-molded body.

FIG. 9 is a cross-sectional shape (a) of a rib of a conventional blow-molded body.
FIG. 4B is a cross-sectional view (b) illustrating the problem.

FIG. 10 is a sectional view (a) of a rib of another conventional blow-molded article and a sectional view (b) illustrating the problem.

[Explanation of symbols]

10, 20, 30 blow molding 11, 12, 21, 22, 31, 32 walls 13, 23, 33 Reinforcing ribs 14, 24, 34 First rib 14a, 34a Side surface of first rib 14b, 34b second rib top surface portion 15, 25, 35 2nd rib 15a, 35a Top of second rib 15b, 35b Plate portion of the second rib 15c, 35c Trapezoidal section of second rib 16, 36 Transition part 17, 37 gap

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuyuki Kanaya             Minoru 447 Shimo-shi, Sanyo-cho, Akaban-gun, Okayama Prefecture             Kasei Co., Ltd. F-term (reference) 4F208 AG06 AG07 AG27 AG28

Claims (2)

[Claims] 1. A double-walled flat blow-molded body is provided with one or more rows of reinforcing ribs, the ribs being arranged alternately in the lengthwise direction of the row and continuous in the lengthwise direction. The first rib includes a first rib and a second rib, and the first rib has a substantially trapezoidal cross section, which is composed of both side surface portions that continuously extend from one wall of the double wall toward the other wall and a narrowed top surface portion. The top surface of the second rib is welded to the inside of the other wall, and the second rib continuously extends from one wall of the double wall toward the other wall, and includes all or a large portion including the top. A blow-molded body characterized in that the portions are welded to each other to form a plate-like shape, and the top portion thereof has a gap between the other wall. 2. A flat blow molding having a double wall is provided with one or more rows of reinforcing ribs, the ribs being alternately arranged in the length direction of the row and continuous in the length direction. A pair of a first rib and a second rib, the first rib being composed of one side wall and one side wall of the double wall extending continuously toward the opposing wall and a narrowed top surface. Of the cross section having a substantially trapezoidal cross section, and the respective facing top surface portions are welded to each other at an intermediate position of the double wall, and the second rib is 2
The one or more walls of the heavy wall continuously extend toward the opposing wall, and all or most of the respective portions including the opposing tops are welded to each other to form a plate shape, and the opposing tops are A blow molded product having a gap between them.