JP2013083310A - Double wall blow molded body - Google Patents

Abstract

A double wall blow molded article having a high cushioning property at the initial stage of compression, being able to prevent ribs from collapsing due to a compressive load, and having high impact absorption.
A groove-shaped first rib 3 recessed from the wall 1 toward the wall 2 and a groove-shaped second rib 4 recessed from the wall 2 toward the wall 1 are formed. 4 is substantially orthogonal in plan view. In the first rib 3 and the second rib 4, the bottom walls 12 and 15 are positioned at substantially the center of the double wall, and the bottom walls 12 and 15 are welded to each other at the crossing portion 16. The first rib 3 and the second rib 4 are desirably engaged with each other. The first rib 3 and the second rib 4 have a draft angle, and when the compressive load acts in the thickness direction of the double wall and the double wall blow molded body undergoes crushing deformation, both side walls 10 of the first rib 3 11 and both side walls 13 and 14 of the second rib 4 project inside the concave groove and contact each other in the process of crushing deformation, obstructing the other side bending deformation and increasing the resistance to compressive load.
[Selection] Figure 2

Description

  The present invention relates to a double wall blow molded article in which reinforcing ribs that are recessed from both walls of a double wall toward an opposing wall are formed, and more particularly to a double wall blow molded article having improved cushioning properties.

  FIG. 1 of Patent Document 1 describes a double-wall blow-molded body in which a plurality of concave (tubular) ribs that are recessed from both walls of the double wall toward the opposing wall are formed. A concave rib that is recessed from one wall of the double wall toward the other wall and a concave rib that is recessed from the other wall of the double wall toward one wall form a pair. The tops of each other are welded at the center of the heavy wall, or the tops are arranged close to each other. According to the description in Patent Document 1, this double-wall blow molded article is suitable for use as a shock absorber for a vehicle because rigidity is prevented from suddenly decreasing during the crushing deformation and high shock absorption continues. .

  FIG. 5 of Patent Document 2 describes a double-wall blow-molded body in which a plurality of concave (groove-shaped) ribs that are recessed from both walls of the double wall toward the opposing wall and are parallel to each other are formed. . Each concave rib includes a first rib having a substantially trapezoidal cross section along the length direction of the row, and a second rib having a plate shape in whole or most including the top. A concave rib that is recessed from one wall of the double wall toward the other wall and a concave rib that is recessed from the other wall of the double wall toward one wall form a pair. The tops of one rib are welded at the center of the double wall along the length direction of the concave rib. According to the description of Patent Document 2, this double wall blow molded article has a strong resistance to bending load, shear load and compression load, and is unlikely to buckle. Suitable.

JP 2004-314647 A Japanese Patent Laid-Open No. 2003-165152

  In the double wall blow molded article described in Patent Documents 1 and 2, all the concave ribs are paired with the concave ribs that are recessed from the opposing wall, and the tops are welded or close to each other at the approximate center of the double wall. Therefore, the resistance to compression load (compression rigidity) is high in the early stage of compression, and the cushioning property (function to soften impact) in the early stage of compression is small. Further, since the concave ribs are cylindrical in the double wall blow molded article of Patent Document 1, all the concave ribs are arranged in the same direction in the double wall blow molded article of Patent Document 2, so When the crushing (crushing) proceeds in the thickness direction, the concave ribs tend to collapse depending on the direction of the load. In this case, the resistance to the compressive load is reduced and the shock absorption (energy absorption amount) is also reduced.

  The present invention has been made to solve such a problem with a double-wall blow molded body in which reinforcing ribs that are recessed from both walls of the double wall toward the opposite wall are formed. An object of the present invention is to obtain a double wall blow molded article that has a high initial cushioning property and can prevent the rib from collapsing due to a compressive load.

  In the double-wall blow molded article according to the present invention, one or more rows of groove-shaped first ribs that are recessed from one wall of the double wall toward the other wall are formed, The second ribs that are recessed toward one wall are formed in one or a plurality of rows, the first and second ribs are substantially orthogonal in a plan view, and the bottom walls do not reach the opposing walls of the double walls. The bottom walls are welded to each other at the portion. The first rib and the second rib are preferably engaged with each other. Further, the first and second ribs have a draft angle, and when the compressive load acts in the thickness direction of the double wall and the crushing deformation occurs, both side walls of each rib project to the inside of the concave groove, and the crushing deformation It is desirable to contact each other in the process.

  In the double-wall blow molded article according to the present invention, the first and second ribs are substantially orthogonal in a plan view, the bottom wall is not welded to the opposing wall, and both ribs are welded to each other only at the intersection. . For this reason, the resistance force to the compressive load at the initial stage of compression is smaller than that of the conventional double wall blow-molded body (see Patent Documents 1 and 2), and the cushioning property at the initial stage of compression is high. Further, the rib can be prevented from collapsing due to the compressive load, and accordingly, the impact absorption can be prevented from being lowered during the crushing deformation process. In particular, when crushing deformation, if both side walls of each rib protrude inside the concave groove and come into contact with each other in the process of crushing deformation, the resistance force increases with the crushing deformation and the shock absorption is also increased. .

It is a perspective view of the double wall blow molded object which concerns on this invention. It is AA sectional drawing of the double wall blow molding of FIG. It is AA sectional drawing (a) in case the 1st, 2nd rib of the double wall blow molding of FIG. 1 has meshed | engaged, and BB sectional drawing. It is AA sectional drawing (a) in case the 1st, 2nd rib of the double wall blow molding of FIG. 1 is meshing with another form, and BB sectional drawing. It is sectional drawing which shows the other form of a 1st rib. It is a schematic diagram which shows the graph of the thickness-compressive stress when applying a compressive load to the double wall blow molding which concerns on this invention, and carrying out the crushing deformation | transformation, and a corresponding deformation | transformation form. It is the corner pad which applied the double wall blow molding concerning the present invention, and is the developed top view (a), perspective view (b), and assembly drawing (c).

Hereinafter, with reference to FIGS. 1-7, the double wall blow molded object which concerns on this invention is demonstrated.
The double wall blow molded body shown in FIGS. 1 and 2 includes double walls 1 and 2, concave groove-like first ribs 3 recessed from wall 1 toward wall 2, and wall 2 to wall 1. It consists of a concave groove-shaped second rib 4 which is recessed toward the periphery, and peripheral walls 5 to 8 surrounding the four circumferences of the walls 1 and 2. 9 is a mold parting line, and 20 is a pressurized air blowing hole.
The first rib 3 is substantially trapezoidal in cross section and has a draft angle, and is composed of inclined side walls 10 and 11 and a bottom wall 12, and the bottom wall 12 is located at a substantially central portion of the double wall thickness. The second rib 4 is also composed of inclined side walls 13 and 14 and a bottom wall 15, and the bottom wall 15 is located at a substantially central portion of the double wall thickness. The depths of the grooves of the first rib 3 and the second rib 4 (the depth of the bottom wall 12 from the wall 1 and the depth of the bottom wall 15 from the wall 2) are the same as those of the first rib 3 and the second rib 4. It is almost constant along the length direction. The first rib 3 and the second rib 4 are orthogonal to each other in plan view, and the bottom walls 12 and 15 are welded and integrated with each other at the crossing portion 16.

FIG. 3 shows another double wall blow molded article according to the present invention. In FIG. 3, the same reference numerals are assigned to substantially the same parts as the double wall blow molded article shown in FIGS.
The double wall blow-molded body shown in FIG. 3 (only the cross-sectional view) is substantially identical in appearance to the double wall blow-molded body shown in FIGS. 1 and 2 (therefore, the perspective view uses FIG. 1). The 1 rib 3 and the 2nd rib 4 are dented in the shape of a ditch | groove, the bottom walls 12 and 15 are located in the approximate center part of the thickness of a double wall, and the 1st rib 3 and the 2nd rib 4 are crossing parts. 16 is also the same as the double wall blow molded article shown in FIG.

  However, the double groove shown in FIG. 1 is different in that the depth of the concave groove of the second rib 4 (the depth of the bottom wall 15 from the wall 2) is not constant and varies along the length direction of the second rib 4. Different from wall blow molding. Specifically, the depth of the concave groove of the second rib 4 (depth of the bottom wall 15 from the wall 2) is shallow at the crossing portion 16 with the first rib 3, and becomes deep on both sides of the crossing portion 16. Yes. Therefore, it can be said that the first rib 3 and the second rib 4 are engaged with each other in the crossing portion 16 (the first rib 3 is bitten into the second rib 4). With this structure, the first rib 3 and the second rib become stronger against the collapse due to the compressive load.

FIG. 4 shows another double wall blow molded article according to the present invention. In FIG. 4, the same numbers are assigned to substantially the same parts as the double wall blow molded article shown in FIGS.
The double wall blow-molded body shown in FIG. 4 (cross-sectional view only) is substantially identical in appearance to the double-wall blow molded body shown in FIGS. 1 and 2 (therefore, the perspective view uses FIG. 1). The 1 rib 3 and the 2nd rib 4 are dented in the shape of a ditch | groove, the bottom walls 12 and 15 are located in the approximate center part of the thickness of a double wall, and the 1st rib 3 and the 2nd rib 4 are crossing parts. 16 is also the same as the double wall blow molded article shown in FIG.

  However, the depths of the concave grooves of the first rib 3 and the second rib 4 (the depth of the bottom wall 12 from the wall 1 and the depth of the bottom wall 15 from the wall 2) are not constant. 1 differs from the double-wall blow molded article shown in FIG. 1 in that it differs along the length direction of the second rib 4. Specifically, the depths of the concave grooves of the first rib 3 and the second rib 4 (depth of the bottom wall 12 from the wall 1 and depth of the bottom wall 15 from the wall 2) are shallow at the intersection 16. It is deeper on both sides of the crossover part 16. Accordingly, it can be said that the first rib 3 and the second rib 4 are in mesh with each other in the crossing portion 16. With this structure, the first rib 3 and the second rib become stronger against the collapse due to the compressive load.

Although the 1st rib 3 shown in FIGS. 1-4 was substantially trapezoid shape, as shown in FIG. 5, the 1st rib 3 can take the form of another draft. Although not shown, the same applies to the second rib 4. In FIG. 5, the same reference numerals are given to substantially the same portions as the first rib 3 shown in FIG. 2.
The first rib 3 shown in FIG. 5A has a curved shape in which both side walls 10 and 11 protrude inside the concave groove. The 1st rib 3 shown in FIG.5 (b) has the folding parts 17 and 18 from which both side walls 10 and 11 become convex inside a ditch | groove.

  FIG. 6 shows the thickness of the double wall when the compressive load is applied to the double wall blow molded article according to the present invention (the ratio after deformation when the original thickness is 1) −compressive stress. It is a schematic diagram which shows the modification corresponding to this graph. In addition, after a blow molding, it is desirable for a double wall blow molded object to close the pressurized air blowing port 20 (refer FIG. 1), and to seal the hollow interior. In that case, the internal pressure of the double-wall blow molded body increases as the compression deformation proceeds, thereby increasing the compression load and improving the shock absorption.

  When a compressive load is applied in the thickness direction of the double wall blow molded body, the side walls 10, 11, 13, 14 of the first and second ribs 3 and 4 and the peripheral walls 5 to 8 are relatively low at the initial stage of compression. Is curved, and the double-wall blow molded body is compressed and deformed in the thickness direction. Even when the hollow interior of the double-wall blow-molded body is sealed, since the increase in internal pressure is small at the initial stage of compression, the increase in compression load accompanying the sealing is small, and the cushioning property at the initial stage of compression is not hindered. The compressive load at the initial stage of compression is adjusted by the size of the first rib 3 and the corner R of the wall 1 and the second rib 4 and the corner R of the wall 2 (indicated by an arrow 19 in FIG. 2). Can be reduced).

  In the process of compressive deformation, the side wall 9 and side wall 11 of the first rib 3 and the side wall 13 and side wall 14 of the second rib 4 are bent and deformed so as to protrude inside the concave groove, and further the compressive deformation proceeds. And contact with each other along the length direction of the first rib 3 and the second rib 4. The side wall 10 and the side wall 11 of the first rib 3 and the side wall 13 and the side wall 14 of the second rib 4 that are in contact with each other interfere with each other's bending deformation, and as a result, the resistance to compressive load is reduced. Rather it increases. In addition, when there is no contact between the side walls of each rib, there exists a possibility that resistance may fall rapidly by buckling.

FIG. 7 shows a corner pad for product protection comprising a double wall blow molded article according to the present invention. This type of corner pad is disposed at the corner portion of the cardboard to protect the product when the product is stored in the cardboard, and is conventionally formed of foamed polystyrene.
The corner pad shown in FIG. 7 is formed by integrally molding three double wall blow molded bodies 21, 22, and 23. The double wall blow molded bodies 22 and 23 are formed of a double wall blow molded body 21 having a rectangular shape in plan view. They are connected to adjacent sides via hinge portions 24 and 25 that are thin and bendable. When used as a corner pad, the double wall blow molded bodies 22 and 23 are raised vertically to the double wall blow molded body 21 as shown in FIG.
This corner pad is lightweight and has high initial cushioning and high shock absorption. Moreover, at the time of transportation, as shown in FIG.

1, 2 Double wall 3 First rib 4 Second rib 9, 11, 13, 14 Side wall 12, 15 of rib Bottom wall 16 of rib 16 Crossing portion of first and second rib

Claims (3)

A single groove or a plurality of rows of groove-shaped first ribs that are recessed from one wall of the double wall toward the other wall is formed, and a groove-shaped first rib that is recessed from the other wall toward the one wall. The second rib is formed in one or a plurality of rows, the first and second ribs are substantially orthogonal in a plan view, the bottom walls do not reach the opposing walls of the double walls, and the bottom walls are welded to each other at the intersection. A double wall blow molded article characterized by The double-wall blow molded article according to claim 1, wherein the first rib and the second rib are engaged with each other. The first and second ribs have draft angles, and when the compressive load acts in the thickness direction of the double wall and undergoes crushing deformation, both side walls of each rib project to the inside of the concave groove, and in the process of crushing deformation The double wall blow molded article according to claim 1 or 2, wherein the double wall blow molded article is in contact with each other.

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