JP2013091511A - Wall body structure for container and method for manufacturing container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wall body structure for a container and a method for manufacturing the container capable of manufacturing a container which is reduced in weight, at higher productivity than a conventional method.SOLUTION: Since the weight of the container 10 is reduced by light-weight holes 21F and 22F and thin wall portions 21B and 22B, and also the thin wall portions 21B and 22B can be formed into a core-back shape by a resin molding die 50 which can be used to form body wall portions 21A and 22A having the light-weight holes 21F and 22F in the first and the second sidewalls 21 and 22 in accordance with the wall body structure and the method for manufacturing the container 10, it becomes unnecessary to carry out conventional work of sticking a seat and it becomes possible to manufacture the container 10 at the higher productivity than the conventional method. Moreover, it becomes unnecessary to use high fluidity resin for forming the container 10, and therefore, the problem of the decrease in impact resistance or the like is dissolved.

Description

  The present invention relates to a container wall structure having a lightweight hole and a container manufacturing method.

  Conventionally, as a wall structure of this type of container, a sheet having a mesh structure attached to the entire inner surface of a lattice-shaped main body wall portion having a plurality of rectangular lightweight holes is known (for example, Patent Document 1). reference).

JP 2002-37249 A (FIGS. 1, 3 and 4)

  However, the above-described conventional container wall structure has a problem in that the work of attaching the sheet to the main body wall portion takes time and productivity is low. In addition, a wall structure in which a part of the wall body is thinned to eliminate the work of pasting the sheet is also conceivable. However, in this case, it becomes necessary to use a resin with high fluidity, which increases the cost and impact resistance. Problem arises.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a container wall structure and a container manufacturing method capable of manufacturing a lightweight container with higher productivity.

  In order to achieve the above object, the container wall structure according to the invention of claim 1 includes a side wall, a bottom wall, and other walls of a resin container, a main body wall portion having a lightweight hole, and a main body thereof. It is characterized in that it is composed of a lightweight wall portion that is core-back molded with a resin mold that molds the wall portion, closes the lightweight holes, and has a thin structure that is thinner than the mesh structure or the main body wall portion.

  According to a second aspect of the present invention, the container wall structure according to the first aspect is provided with a support wall protruding from the edge of the lightweight hole toward the center of the lightweight hole on one side of the front and back of the main body wall. The outer edge portion of the lightweight wall portion is characterized in that it is fixed to the inner surface of the lightweight hole and the support wall.

  According to a third aspect of the present invention, there is provided a container manufacturing method in which a side wall, a bottom wall, and other walls of a resin container are molded into a structure having lightweight holes by a resin molding die, and then a mesh structure or a main body. It is characterized in that a light-weight wall portion having a thin structure thinner than the wall portion is core-back molded into a lightweight hole by a resin molding die.

  According to a fourth aspect of the present invention, in the container manufacturing method according to the third aspect, before the core back molding, a support wall protruding from the edge of the lightweight hole toward the center of the lightweight hole is formed on the wall body. The outer edge portion of the lightweight wall portion is characterized in that it is core-back molded so as to be fixed to the inner surface of the lightweight hole and the support wall.

  According to a fifth aspect of the present invention, in the container manufacturing method according to the third aspect, the cylindrical portion is provided in the movable core that can be core-backed among the movable molds in the resin mold, and the core cannot be backed in the cylindrical portion. A fixed core is disposed, and further, a mesh-shaped molding groove is formed on a joint surface of the fixed core with the fixed mold of the resin molding die, and a cylindrical portion is provided on the outer surface of the fixed core before the core back of the movable core. The side opening of the molding groove is closed, the inner surface of the lightweight hole is molded on the outer surface of the cylindrical portion, and the movable core is core-backed with the cylindrical portion, so that an annular shape is formed between the fixed core and the inner surface of the lightweight hole. In addition to forming a molding space and opening the side opening of the molding groove in the molding space, filling the molding space and the molding groove with molten resin, and core back molding the lightweight wall part of the mesh structure Features To.

  In the present invention, “core back molding” means molding a part of a resin molding die after core back.

  According to the first and third aspects of the invention, the weight of the container can be reduced by the lightweight hole and the lightweight wall portion, and the lightweight wall can be formed by the resin molding die for molding the main body wall portion having the lightweight hole in the wall body. Since the portion can be core-back molded, a conventional sheet pasting operation is not required, and a container can be manufactured with higher productivity than conventional. Further, it is not necessary to use a resin having high fluidity for molding the container, and accordingly, problems such as a decrease in impact resistance are solved.

  In the inventions of claims 2 and 4, the outer edge portion of the lightweight wall portion is fixed to both the inner surface of the lightweight hole and the support wall projecting from the edge portion of the lightweight hole. Compared with the structure fixed only to the inner surface of the main body, the strength of the fixing portion between the main body wall portion and the lightweight wall portion is increased.

  According to the container manufacturing method of the fifth aspect, the light-weight wall portion having a mesh structure can be formed with a resin molding die having a simple structure.

The perspective view of the container which concerns on 1st Embodiment of this invention. Exploded perspective view of container Partial perspective view of the outer surface side of the second side plate Partial perspective view of the inner surface side of the second side plate Partial perspective view of bottom base Partial side sectional view of the second side plate Side cross section of resin mold (A) Partial sectional side view of resin molding die before core back, (B) Partial sectional side view of resin molding die after core back Partial side sectional view of the second side plate of the second embodiment Partial side sectional view of the resin mold before core back Partial side cross-sectional view of resin mold after core back The partial side view of the 2nd side wall of 3rd Embodiment The side view which separated and showed the main-body wall part and lightweight wall part of the 2nd side wall Partial side sectional view of the resin mold before core back Partial side cross-sectional view of resin mold after core back

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the container 10 of the present embodiment has a rectangular parallelepiped shape in plan view, and the entire upper surface is open. Further, a lattice-like lattice-shaped rib 11 is formed on the entire outer surface of the container 10, and a bulging protrusion 12 protrudes laterally from the upper end edge of the outer surface of the container 10. The bulging protrusion 12 has an angular groove structure in cross section, the groove opening is open to the inner surface of the container 10, and a plurality of connecting ribs 12 </ b> A are provided inside the bulging protrusion 12.

  On the pair of first side walls 21, 21 arranged in the short side portion of the rectangular shape of the container 10, rectangular regions 13 partitioned by the lattice ribs 11 on the outer surfaces thereof are vertically and horizontally. For example, it is provided in a 4 × 3 matrix. A horizontally-long rectangular handle hole 10H is formed through the rectangular region 13 arranged at the center of the uppermost stage. Further, the pair of rectangular areas 13 and 13 arranged at both lateral ends of the uppermost stage are edged from the above-described bulging protrusion 12 at the upper corner on the side away from the handle hole 10H. A triangular bulging protrusion 12B is provided.

  On the pair of second side walls 22 and 22 arranged in the long side portion of the rectangular shape of the container 10, a relatively large rectangular region 13 partitioned by the lattice ribs 11 described above is formed on each outer surface thereof. For example, a matrix of 4 × 3 is provided vertically and horizontally, and a plurality of relatively small vertically long rectangular regions 13 are arranged vertically and horizontally on both sides of the rectangular region 13 group.

  As shown in FIG. 2, the container 10 is a lattice-shaped rib 11 disposed at the boundary between the lowermost rectangular region 13 group and the upper rectangular region 13 group, and includes a bottom base 30 including a bottom wall 14. The other parts are divided into two parts vertically. Further, the upper part of the container 10 above the bottom base 30 is divided into four parts along the both sides of the rectangular region 13 group of each first side wall 21 described above, and includes a part of the first side wall 21 1. The pair is divided into a pair of first side plates 31 and 31 and a pair of second side plates 32 and 32 including the second side wall 22.

  From the lower end portions of the first and second side plates 31 and 32, lower end ribs 11B project laterally. Further, an upper end rib 11 </ b> A projects laterally from the upper end portion of the bottom base 30. These upper end ribs 11A and lower end ribs 11B are overlapped to form the lateral ribs 11Y of the lattice-shaped ribs 11.

  Each lower end rib 11B has a pair of lower end engaging protrusions 33 protruding from both ends of the lower surface thereof, and a pair of square protrusions 34 protruding from the center. Further, as shown in FIG. 3, each of the lower end engaging projections 33 surrounds a projecting piece 33A protruding downward from the lower end rib 11B with a gate-shaped protective frame 33B that also protrudes downward from the lower end rib 11B. The locking projection 33C protrudes from the lower end of the protruding piece 33A.

  On the other hand, as shown in FIG. 2, the upper end rib 11A is provided with a retaining recess 16 at a position corresponding to the lower end engaging protrusion 33 of the lower end rib 11B, and at a position corresponding to the square protrusion 34 of the lower end rib 11B. A positioning hole 17 is provided. As shown in FIG. 5, the retaining recess 16 has an opening on the upper surface of the upper end rib 11A and communicates with the inside of the pocket structure wall 16A extending downward from the lower surface of the upper end rib 11A. A locking hole 16B penetrating the lower end of the side surface is provided. Then, when the lower end rib 11B is overlaid on the upper end rib 11A, the rectangular protrusion 34 is inserted into the positioning hole 17, and the lower end engaging protrusion 33 is inserted into the retaining recess 16 to engage the locking protrusion 33C. The lower end rib 11B is retained in the state of being overlapped with the upper end rib 11A. The bottom wall 14 of the bottom base 30 is provided with a plurality of bottom surface recesses 15 that are recessed in a stepped manner in a matrix.

  As shown in FIG. 2, a pair of vertical ribs 11C and 11C are provided on both sides of the first side plate 31, and a plurality of connecting hooks 35 project laterally from the outer surfaces of the vertical ribs 11C and 11C. ing. Each connecting hook 35 has a shape that protrudes horizontally from the vertical rib 11C and then bends upward at a right angle. On the other hand, a pair of side curved portions 36, 36 that are bent at right angles toward the pair of first side plates 31, 31 are provided on both sides of the second side plate 32. As shown in FIG. 4, the side curved portion 36 has a pair of opposing walls 36A, 36A that face each other in the width direction of the longitudinal rib 11C (see FIG. 2) of the first side plate 31, and these opposing walls 36A, 36A. Are connected to each other by a plurality of communication walls 36 </ b> B and partitioned into a plurality of engagement holes 37. The second side plate 32 is lowered with respect to the first side plate 31 with the connection hook 35 group of the first side plate 31 inserted into the engagement hole 37 group of the second side plate 32, and the connection hook 35 group communicates. The first and second side plates 31 and 32 are held in a state where they are locked to the back side of the wall 36B.

  Now, in the container 10 of the present embodiment, a part of the first and second side walls 21 and 22 is composed of relatively thin thin wall portions 21B and 22B (corresponding to the “lightweight wall portion” of the present invention). ing. Specifically, as shown in FIG. 1, in the second side wall 22, each of the first and second tiers from the top of the group of rectangular regions 13 arranged in a matrix of 4 × 3 vertically and horizontally. A quadrilateral in which the thickness of the second side wall 22 is reduced in a stepped manner on each outer surface of each of the three rectangular regions 13 groups and on the outer surfaces of the rectangular regions 13 and 13 at both lateral ends of the third step from the top. The recesses 22E are recessed and the bottoms of the recesses 22E are thin wall portions 22B as shown in FIG. More specifically, a portion of the second side wall 22 other than the thin wall portion 22B is a main body wall portion 22A provided with a lightweight hole 22F formed in a portion corresponding to the concave portion 22E. The lightweight hole 22F group of the portion 22A is closed by the thin wall portion 22B group, and a recess 22E is formed by a step between the outer surface of the thin wall portion 22B and the outer surface of the main body wall portion 22A.

  As shown in FIG. 1, the first side wall 21 includes the outer surface of the three rectangular regions 13 in the second row from the top among the rectangular regions 13 arranged in a matrix of 4 × 3 in the vertical and horizontal directions. A rectangular recess 21E in which the wall thickness of the first side wall 21 is reduced in a stepped shape is formed in the outer surface of the rectangular regions 13 and 13 at both lateral ends of the third step from the bottom, and the bottom of the recess 21E is thin. It is a wall portion 21B. Similarly to the second side wall 22, the first side wall 21 also has a main body wall portion 21 </ b> A in which a portion other than the thin wall portion 21 </ b> B is formed by penetrating a lightweight hole 21 </ b> F in a portion corresponding to the recess 21 </ b> E. The light-weight holes 21F of the main body wall 21A are closed by the thin-walled walls 21B. The first and second side walls 21 and 22 have a wall thickness of a portion other than the thin wall portions 21B and 22B, for example, 1.5 to 2.5 [mm], whereas the thin wall portion 21B. , 22B is, for example, 0.5 to 1.5 [mm].

  FIG. 7 shows a resin molding die 50 for molding the second side plate 32. The resin molding die 50 includes a movable mold 51 that can move linearly with respect to the fixed mold 52, a mold closed state in which a part of the front surface of the fixed mold 52 and a part of the front surface of the movable mold 51 are joined, and a fixed mold. The mold can be switched to a mold open state in which the movable mold 51 is separated from the mold 52. Moreover, the movable core 51K is assembled to the movable mold 51 so as to be able to move linearly.

  In order to mold the second side plate 32 with this resin molding die 50, the movable core 51K is placed in the origin position on the front end side of the movable range with the mold closed, and the front surface of the movable core 51K is set to the front surface of the fixed mold 52. Join. In this state, as shown in FIG. 8A, the resin is melted from the resin supply passage 54 of the fixed mold 52 into the first molding space C1 formed between the front surface of the movable core 51K and the front surface of the fixed mold 52. Resin (for example, polypropylene) is filled, and the side plate body 32A excluding the thin wall portion 22B group in the second side plate 32 is molded. Here, the portion corresponding to the second side wall 22 of the side plate main body 32A is the main body wall portion 22A. In the resin mold 50, the inner surface of the second side wall 22 is molded on the fixed mold 52 side, and the outer surface of the second side wall 22 is molded on the movable mold 51.

  Next, as shown in FIG. 8B, the movable core 51K is moved to the core back position on the rear end side of the movable range while the mold is closed, and the front surface of the movable core 51K is positioned in the middle of the lightweight hole 22F in the axial direction. Place in position. As a result, a second molding space C <b> 2 is formed between the front surface of the movable core 51 </ b> K and the front surface of the fixed mold 52, which is thinner than the plate thickness of the flat plate portion 22 </ b> C around the lightweight hole 22 </ b> F. In this state, molten resin (for example, polypropylene) is filled into the second molding space C2 from the resin supply path 53 of the fixed mold 52 to mold the thin wall portion 22B (core back molding). In this way, the second side plate 32 is completed. The same applies to the first side plate 31. Further, the bottom base 30 is molded by a resin forming mold without performing core back. Then, the container 10 is completed by assembling the separately formed bottom base 30, the pair of first side plates 31, 31 and the pair of second side plates 32, 32 to each other.

  As described above, according to the wall structure and the manufacturing method of the container 10 of the present embodiment, the weight of the container 10 is reduced by the lightweight holes 21F and 22F and the thin wall portions 21B and 22B. The thin wall portion 21B is a resin molding die 50 (the resin molding die for the first side wall 21 is not shown) for molding the main body wall portions 21A and 22A having the light-weight holes 21F and 22F among the side walls 21 and 22. , 22B can be core-back molded, so that a conventional sheet pasting operation is not required, and the container 10 can be manufactured with higher productivity than in the past. Further, it is not necessary to use a resin having high fluidity for molding the container 10, and accordingly, problems such as a decrease in impact resistance are solved.

[Second Embodiment]
A second embodiment of the present invention is shown in FIGS. 9 to 11, and the container of this embodiment includes a lightweight hole 22 </ b> F from the edge of the lightweight hole 22 </ b> F of the second side plate 32 </ b> V, as shown in FIG. A support wall 22D is projected toward the center of the. The outer edge portion of the thin wall portion 22B is fixed to the inner surface of the lightweight hole 22F and the support wall 22D. Although not shown, the first side plate is similarly provided with a support wall. Other structures related to the container are the same as those of the container 10 of the first embodiment.

  10 and 11 show a resin molding die 50V for molding the second side plate 32V described above. In the resin molding die 50V, the outer surface of the second side wall 22 is molded by the fixed mold 52V, and the inner surface of the second side wall 22 is molded by the movable mold 51V. An annular groove 52M is formed on the front surface of the fixed mold 52V so as to face the outer edge portion of the front surface of the movable core 51K. Other structures relating to the resin mold 50V are the same as those of the resin mold 50 of the first embodiment.

  In order to mold the second side plate 32V with the resin molding die 50V, as shown in FIG. 10, the resin molding die 50V is closed and the movable core 51K is placed at the origin position. In this state, the resin molding is performed. The first molding space C1 formed in the mold 50V is filled with molten resin to mold the side plate body 32A having the support wall 22D described above. Then, as shown in FIG. 11, the movable core 51K is moved to the core back position, the molten resin is filled in the second molding space C2 formed in the resin molding die 50V, and the thin wall portion 22B is molded. .

  According to the container wall structure and the manufacturing method of the present embodiment, the outer edge portion of the thin wall portion 22B is fixed to both the inner surface of the lightweight hole 22F and the support wall 22D protruding from the edge portion of the lightweight hole 22F. Therefore, the strength of the fixing portion between the main body wall portion 22A and the thin wall portion 22B is increased.

[Third Embodiment]
12 to 15 show a third embodiment according to the present invention. FIG. 12 shows a peripheral portion of the lightweight hole 22F in the second side wall 22 in the container of the present embodiment. In this container, a lightweight wall portion 22X formed inside the lightweight hole 22F includes, for example, a frame portion 22H having the same thickness as the flat plate portion 22C of the main body wall portion 22A, and a flat plate formed inside the frame portion 22H. The mesh wall 22G has a mesh structure having the same thickness as the portion 22C. In addition, although not shown, the first side plate is similarly provided with a lightweight wall portion including a frame portion and a mesh wall. Other structures related to the container are the same as those of the container 10 of the first embodiment.

  14 and 15 show a resin molding die 50W for molding the second side plate (not shown) including the second side wall 22 described above. In this resin molding die 50W, the portion of the movable core 51N that molds the inner surface of the lightweight hole 22F is a cylindrical portion 51T, and a fixed core 51S that is fixed inside the cylindrical portion 51T so as to prevent core back is provided. It has been. In addition, a mesh-shaped mesh forming groove 51U is formed on the front surface of the fixed core 51S joined to the fixed mold 52. Further, the net-shaped groove 51U is open to the side surface of the fixed core 51S, and the side surface opening can be closed by the cylindrical portion 51T.

  In order to mold the second side plate with the resin molding die 50W, as shown in FIG. 14, the resin molding die 50W is closed and the movable core 51N is placed at the origin position. The first molding space C1 formed in the mold 50W is filled with molten resin to mold the side plate main body 32A having the above-described lightweight hole 22F (see the upper portion in FIG. 13). Next, as shown in FIG. 15, the movable core 51N is moved to the core back position. Then, an annular molding space C3 is formed between the side surface of the fixed core 51S and the inner surface of the lightweight hole 22F, and the side surface opening of the net-shaped groove 51U communicates with the molding space C3. In this state, the molten resin is filled from the resin supply path 53 provided in the fixed mold 52 into the net-forming groove 51U and the molding space C3, and the above-described lightweight wall portion 22X (see the lower portion in FIG. 13) is molded. .

  The container wall structure and the manufacturing method of the present embodiment also provide the same effects as the first embodiment.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

(1) In the above embodiment, the main body wall portions 21A and 22A and the thin wall portions 21B and 22B are formed of the same resin, but may be formed of different resins. For example, one of the main body wall portion and the thin wall portion may be formed of a resin having higher transparency than the other or a resin having higher rigidity.

(2) In the above embodiment, only the first and second side walls 21 and 22 are provided with the thin wall portions 21B and 22B. However, the bottom wall 14 may be provided with the thin wall portion, and the container may be covered with the lid. And a thin wall portion may be provided on the lid.

10 Container 14 Bottom wall (wall)
21 1st side wall (wall body)
21A, 22A Body wall 21B, 22B Thin wall (lightweight wall)
21F, 22F Lightweight hole 22 2nd side wall (wall body)
22D Support wall 22G Mesh wall 22H Frame portion 22X Lightweight wall portion 50, 50V, 50W Resin molding die 51K, 51N Movable core 51T Tube portion 51U Net forming groove (molding groove)

Claims (5)

  The side wall, bottom wall, and other walls of the resin container are core-back molded with a body wall portion having a lightweight hole and a resin mold for molding the body wall portion to close the lightweight hole and mesh A wall structure of a container characterized by comprising a light-weight wall portion having a structure or a thin wall structure thinner than the main body wall portion.   A support wall that protrudes from an edge of the lightweight hole on one side of the front and back surfaces of the main body wall portion toward the center of the lightweight hole is provided, and an outer edge of the lightweight wall portion includes an inner surface of the lightweight hole and the The wall structure of a container according to claim 1, wherein the container wall structure is fixed to the support wall.   After the side wall, bottom wall, and other walls of the resin container are molded into a structure having a lightweight hole by a resin molding die, a lightweight wall portion having a mesh structure or a thin wall structure thinner than the main body wall portion, A method for manufacturing a container, comprising core molding into the lightweight hole by the resin molding die.   Before the core back molding, a support wall protruding from the edge of the lightweight hole toward the center of the lightweight hole is formed on the wall body, and the outer edge of the lightweight wall is formed on the lightweight hole. 4. The container manufacturing method according to claim 3, wherein core back molding is performed so as to be fixed to an inner surface and the support wall. Among the movable molds in the resin molding die, a cylindrical portion is provided in a movable core that can be core-backed, a fixed core that cannot be core-backed is disposed inside the cylindrical portion, and the resin molding die in the fixed core is further provided. Form a mesh-shaped forming groove on the joint surface with the fixed mold of
Before the core back of the movable core, the cylindrical portion closes the side opening of the molding groove on the outer side surface of the fixed core and molds the inner side surface of the lightweight hole on the outer side surface of the cylindrical portion,
The movable core is core-backed with the cylindrical portion, thereby forming an annular molding space between the fixed core and the inner surface of the lightweight hole, and opening a side opening of the molding groove in the molding space. 4. The container manufacturing method according to claim 3, wherein the molding space and the molding groove are filled with a molten resin, and the lightweight wall portion of the mesh structure is core-back molded.

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