Manufacturing method of transport container

Abstract

To provide a transport container in which a receiving member having a complicated shape is attached by bending an injection-molded preform from the center and forming vacuum-molded convex shapes on both sides. [Solution] The preform 10 has left and right vacuum-forming target portions 13, left and right closed-curve-shaped gripped portions 12, a hinge portion 11 sandwiched between the gripped portions 12, and multiple engagement portions 14 provided on the periphery of the preform 10. The thickness of the hinge portion 11 decreases along its entire length from the adjacent gripped portions 12 on both sides toward the center, and a linear fold line portion 11a having a thickness that allows manual bending is formed at the center. The preform 10 is formed by sandwiching the gripped portions 12 from above and below between an upper frame 41 and a lower frame 42, and the vacuum-forming target portion 13 is heated to vacuum-form a convex shape. The base 20 has notches 24 and 25 on each intersecting surface, and the engagement portions 14 are attached to these notches.

Description

[Technical Field]

[0001] The present invention relates to a transport container having a receiving member on which products, parts, etc. are placed, and more particularly to a method for manufacturing a transport container that can be manufactured inexpensively by reducing the number of parts. [Background technology]

[0002] Transport containers used for transporting and transporting products, parts, etc. (hereinafter referred to as "products, etc.") are equipped with support members to prevent the products, etc. from being scratched or broken. These support members have three-dimensional curved surfaces that conform to the shape of the products, etc., so that they can reliably support the products, etc. However, the manufacture of support members with such shapes inevitably requires high-mix, low-volume production to accommodate customer products, etc.

[0003] Patent Document 1 discloses a transport container having a receiving member with a three-dimensional curved surface, which is formed by vacuum forming. The receiving member in Patent Document 1 is vacuum formed from a thermoplastic sheet such as polypropylene. It is vacuum formed into a single convex shape, combining vacuum-formed portions on the left and right and a valley portion that divides the center by a straight line. After forming, the portion is bent into an L shape at the valley portion, so that one vacuum-formed portion remains horizontal and the other vacuum-formed portion stands upright. The transport container is then completed by attaching the receiving member to a base using two fasteners.

[0004] In vacuum forming, after forming the desired vacuum-formed target portion in the resin sheet, there are problems in that a lot of scrap is discarded because the resin sheet is cut at the area surrounding the vacuum-formed target portion. Also, a separate fastener is required to secure the receiving material to the nest box.

[0005] Patent Document 2 discloses a preform in which the peripheral portion is pre-formed by injection molding to form a joint for attaching the support to a base, and the central portion is prepared as a target portion for vacuum forming to allow the support to be shaped specifically for the customer. The desired convex shape is vacuum-formed in the target portion of the preform, and the peripheral engaging portion is attached to the base to complete the transport container. Attaching the container to the base does not require the use of separate fasteners, and the amount of scrap discarded can be reduced compared to conventional vacuum forming techniques using thermoplastic sheets. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7343247 [Patent Document 2] Patent No. 7215795 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] In Patent Document 1, a complex shape is formed by simultaneously forming a central valley and convex shapes on either side of the valley in a thermoplastic sheet of uniform thickness, and then bending the sheet at the valley. On the other hand, the preform in Patent Document 2 is formed using injection molding technology, and the thickness of the central portion where vacuum forming is performed is set to, for example, 4.5 mm. With such a thickness, even if one attempts to simultaneously form a central valley and convex shapes on either side of the valley, as in Patent Document 1, and then fold the sheet at the valley, it is difficult to control the thickness so that only the valley is uniformly thin enough to be bent during vacuum forming.

[0008] Therefore, in the preform of Patent Document 2, if the vacuum-formed target part that is vacuum-formed during injection molding is controlled to a thin thickness of 0.5 mm or less so that it can be bent, it is possible to simultaneously form a valley in the center and convex shapes on both sides of that, as in Patent Document 1, in the vacuum-formed target part, and then bend it at the valley part to form a complex shape.

[0009] However, it is quite difficult to create a preform with such a thin vacuum-molded portion using injection molding. If a gate is placed in the vacuum-molded portion, the molten resin will flow from the thin portion to the thick portion, and the resin will begin to cool in the thin portion, blocking the flow to the thick portion. Measures such as adding gates to the peripheral portion would result in the mold becoming more complex.

[0010] The object of the present invention is to solve the above problems and to provide a transport container in which a complex-shaped receiving member is attached by bending an injection-molded preform from the center and vacuum-forming the left and right convex shapes. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a preform that is flat and rectangular in plan view, and has left and right vacuum forming target portions, left and right gripped portions in the form of closed curves that continuously surround the peripheries of the left and right vacuum forming target portions, a hinge portion that is sandwiched between the left and right gripped portions and crosses the preform in a straight line, and a plurality of engaging portions that are provided on the periphery of the preform on both sides of the hinge portion, the thickness of the hinge portion decreasing from the gripped portions on both sides adjacent to the hinge portion toward the center over its entire length, and a linear fold line portion that is thick enough to be manually bent is formed at the center, by injection molding the preform, Surrounding the periphery of each of the left and right vacuum forming target parts The upper and lower frames, each having a closed curved pressing surface, sandwich the hinge portion from above and below. This blocks the heat from the heater, the vacuum forming target part With the heater Heat it and vacuum mold it into a convex shape. On a base with notches on each intersecting surface, Fold it at the hinge The transport container is manufactured by attaching the engaging portion. In addition, in the above-mentioned vacuum forming, an upper frame body and a lower frame body having pressing surfaces surrounding the periphery of the left and right vacuum-formed target parts in the left and right gripped parts and covering the hinge part may sandwich the part from above and below to block heat from the heater, and the vacuum-formed target part may be heated by the heater to vacuum-form a convex shape. [Effects of the Invention]

[0012] According to the present invention, the hinge portion, which is a thin portion, is formed by injection molding, and then the gripped portion adjacent to the hinge portion is held down and fixed with a frame, thereby preventing deformation caused by pressing the mold against the hinge portion after heating by the heater from propagating to the hinge portion. Therefore, the linearity and thickness of the fold line of the hinge portion can be maintained the same as during injection molding. At the same time, by holding down and fixing the gripped portion of the preform with the frame, the frame has the effect of insulating the heat from the heater, preventing thermal effects such as melting or cutting of the fold line of the hinge portion. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams showing a transfer container, in which FIG. 1A is a perspective view of the transfer container and the container, and FIG. 1B is a diagram showing a state in which a base and a preform have been removed from the container. [Figure 2] 2A and 2B are views showing a preform and a base, with FIG. 2A showing the front side of the preform, FIG. 2B showing the back side of the preform, and FIG. 2C showing a development of the base. [Figure 3] 10A and 10B are diagrams showing the process of connecting the preform and the base. [Figure 4] 1A and 1B are diagrams illustrating the vacuum forming process. [Figure 5] 10A to 10C are diagrams illustrating other vacuum forming processes. [Figure 6] 10A to 10C are diagrams illustrating other vacuum forming processes. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figure 1 shows a transport container 1 and a container 30, where Figure 1A is an oblique view of the transport container 1 housed in the container 30, and Figure 1B is a view showing the base 20 and preform 10 removed from the container 30.

[0015] The transport container 1 has a three-dimensional shape (hereinafter referred to as the "desired convex shape") required to accommodate the product w. The transport container 1 comprises a preform 10 and a base 20. The transport container 1 is accommodated in a container 30. The transport container 1 of this embodiment corresponds to a TP-standard container 30. TP-standard containers are plastic containers that are standardized so that they can be stacked even if the container sizes are different, and are widely used in Japan for logistics.

[0016] FIG. 1B shows the base 20 and preform 10 removed from the container 30. Preferred examples of materials for the base 20 include synthetic resin and corrugated cardboard. In this embodiment, the base 20 is formed by performing a predetermined cutout process on plastic corrugated cardboard (hereinafter referred to as "plastic cardboard"), an example of synthetic resin. One preform 10 can be fixed to each end of the base 20. Each preform 10 is folded in half at its center, and desired convex shapes are formed on the left and right vacuum forming target portions 13. The desired convex shapes are formed by vacuum forming to have a shape suitable for mounting a product M, etc. Furthermore, multiple engagement portions 14 that connect to the base are formed by injection molding on the periphery of the preform 10.

[0017] 2A is a perspective view of the front side of preform 10 after injection molding but before vacuum forming, FIG. 2B is a perspective view of the back side of preform 10 in FIG. 2A, and FIG. 2C is a developed view of base 20. Preform 10 is an injection-molded product made of thermoplastic resin, in the shape of a flat plate with a uniform thickness (e.g., 3 mm) throughout, and rectangular in plan view. Polypropylene was used as the thermoplastic resin used for preform 10. Preform 10 may also be made of thermoplastic resins such as polyester, polyolefin, polyamide, polycarbonate, and elastomer.

[0018] 2A and 2B, preform 10 is injection molded to have left and right vacuum-formed portions 13, left and right gripped portions 12 in the form of closed curves that continuously surround the left and right vacuum-formed portions 13, a hinge portion 11 that is sandwiched between left and right gripped portions 12 and crosses preform 10 in a straight line, and a plurality of engaging portions 14 that are provided on the periphery of preform 10 on both sides of hinge portion 11. Note that the dashed-dotted lines in the figures are used to indicate the position of the boundary between gripped portion 12 and hinge portion 11 or the boundary between gripped portion 12 and vacuum-formed portion 13, and do not appear as a texture on the surface of preform 10.

[0019] The left and right vacuum forming target portions 13 and the gripped portion 12 are both formed in the same continuous flat plate shape with a thickness (3 mm), and the boundary between them is indistinguishable in the preform 10 state before vacuum forming. In the vacuum forming target portion 13, an indentation PM (see FIG. 1B) is formed around the desired convex shape. The indentation PM is formed during vacuum forming, and will be described later.

[0020] In the hinge portion 11, the thickness of the plate decreases from the adjacent gripped portions 12 on both sides toward the center along its entire length, and a linear fold portion 11a having a thickness of, for example, 0.5 mm that can be manually bent to the center is formed on the front side of the preform 10.

[0021] Each engaging portion 14 is injection molded so as to protrude from the rear side of the preform 10. In this embodiment, the engaging portions 14 are provided at four diagonal positions on the periphery of the preform 10. The engaging portions 14 include a first fitting portion 14a, a hook portion 14c that protrudes further from the first fitting portion 14a and is provided so as to be freely bendable, and a second fitting portion 14b that faces the first fitting portion 14a, and the second fitting portion 14b is further provided with a catch portion 14d that receives a claw 14e at the tip of the hook portion.

[0022] 2C, the base 20 is cut out from a piece of plastic and has a center 21 that corresponds to the inside bottom surface of the container 30 and end portions 22, 22 on both sides, with folding portions 23 provided between the center 21 and each of the end portions 22, 22, and is folded at the folding portions 23 and placed inside the container 30. At this time, the base 20 is cut to a rectangular size that is stable in the container 30.

[0023] At the bending portion 23, the plastic sheet is cut leaving only one of the front and back surfaces to make it easier to bend. By bending at the bending portion 23, the center portion 21 and the end portions 22, 22 can be made into a state of planes that intersect with each other.

[0024] The base 20 is fitted with one preform 10, straddling the center 21 and each of the end portions 22, 22. The base 20 is provided with two notches 24, 25 at positions corresponding to one of the engagement portions 14 of the preform 10. Four notches 24, 25 are provided in the center 21, and two are provided at each of the end portions 22, 22. Most of the notches 24, 25 are square-shaped, but the notches 25 located at the end of the preform 10 are U-shaped. The opposing first and second fitting portions 14a, 14b are inserted into the notches 24, 25, respectively. The positional relationship between the preform 10 and the base 20 is determined by the first and second fitting portions 14a, 14b and the notches 24, 25.

[0025] 3 is a diagram showing the process of connecting the preform 10 and the base 20 after vacuum molding. The first and second fitting portions 14a and 14b are inserted into the notches 24 and 25, respectively, so that the hook portion 14c protrudes from the back side of the base 20. The hook portion 14c is bent, and the claw 14e at the tip is hooked onto the catch portion 14d of the second fitting portion 14b (see FIGS. 2A and 2B). The base 20 is then bent together with the preform 10 to obtain the configuration shown in FIG. 1B.

[0026] 4 is a diagram showing the vacuum forming process. Preform 10 is placed between an upper frame (opening / closing frame) 41 and a lower frame (fixed frame) 42. Frames 41 and 42 have pressing surfaces 41a and 42a in the form of closed curves that continuously surround gripped portion 12. Preform 10 is placed in a position where upper frame 41 and lower frame 42 can sandwich the entire circumference of gripped portion 12 on one side (left side in the drawing) of preform 10 from above and below (FIG. 4A).

[0027] The gripped portion 12 is clamped and fixed between the pressing surfaces 41a, 42a of the frames 41, 42 from above and below. A heater 44 is placed in the area surrounded by the upper frame 41, and the vacuum-forming target portion 13 on the left side is heated (Fig. 4B). The heater 44 is removed, and a mold 43 is pressed from below, while simultaneously suctioning the air from inside the lower frame 42 (Fig. 4C). The same process is performed on the gripped portion 12 and vacuum-forming target portion 13 on the other side (right side of the drawing) (Fig. 4D). The vacuum-formed preform 10 is completed (Fig. 4E).

[0028] During heating for vacuum forming, the gripped portions 12, 12 surrounding the left and right vacuum forming target portions 13, 13 of the preform 10 are pressed against the upper frame 41 and the lower frame 42, thereby suppressing deformation due to heat. On the other hand, the vacuum forming target portion 13 inside the upper frame 41 and the lower frame 42 is softened by heat, and is deformed overall as the mold 43 is pressed against it from below. As a result, the desired convex shape and the indentation marks PM (FIG. 1B) are formed around it.

[0029] According to this embodiment, the hinge portion 11 having a thin portion is formed by injection molding. Then, the gripped portion 12 adjacent to the hinge portion 11 is pressed and fixed by the frames 41 and 42. Because the frames 41 and 42 are used to fix the hinge portion 11 while avoiding the hinge portion 11, deformation caused by the pressing of the mold 43 after heating by the heater 44 is prevented from spreading to the thin portion of the hinge portion 11. Therefore, the straightness and thinness of the folding line 11a of the hinge portion 11 can be maintained the same as during injection molding. Because the heat from the heater 44 is blocked by the frames 41 and 42, heating of the hinge portion 11 is suppressed, preventing melting and cutting of the thin portion.

[0030] Furthermore, according to this embodiment, a receiving member having a complex convex shape can be easily produced by bending at the hinge portion 11. Furthermore, since the preform 10 is fixed to the base 20 by the engagement portion 14 formed by injection molding, no other fastening member is required.

[0031] In this embodiment, a single sheet of plastic board is used as the base 20, but notches 24, 25 may be drilled in the intersecting surfaces (for example, the bottom and side surfaces) of the container 30, and the preform 10 may be directly attached thereto. In this case, the transport container is composed of the preform 10 and the container 30. Alternatively, the base may be a frame made of rectangular pipes arranged lengthwise and crosswise, and notches 24, 25 may be drilled in the intersecting surfaces of the frame, and the preform 10 may be directly attached thereto. Alternatively, the preform 10 may be directly attached to a base 20 that has been bent into a U-shape by machining in advance. In this case, it becomes possible to use a hard material, such as a steel plate, for the base 20.

[0032] FIG. 5 illustrates another vacuum forming process. In the example of FIG. 4, the left and right vacuum forming target portions 13 were vacuum formed one by one. In this example, the left and right vacuum forming target portions 13 are vacuum formed in parallel. Vacuum forming is performed using a vacuum forming apparatus equipped with an upper frame 41, a lower frame 42, a heater 44, and a mold 43, respectively, corresponding to the left and right vacuum forming target portions 13. In this embodiment, the frame 41 and the frame 42 hold and fix the gripped portion 12 adjacent to the hinge portion 11, excluding the hinge portion 11. This prevents deformation due to the pressing of the mold 43 after heating by the heater and the thermal effect of the heater 44 from spreading to the thinner portion of the hinge portion 11. Note that the processes in FIGS. 5A, 5B, and 5C correspond to those in FIGS. 4A, 4B, and 4C, respectively.

[0033] Furthermore, as shown in Figure 6, by integrating the left and right upper frame bodies 41 and the left and right lower frame bodies 42, the hinge portion 11 can also be held down and fixed by the frame bodies 41, 42, which further prevents deformation due to the pressing of the mold 43 and the thermal effects of the heater 44 from spreading to the thin parts of the hinge portion 11. At the same time, because the hinge portion 11 is covered by the integrated upper frame body 41, it is possible to combine the heater 44 into one continuous unit on the left and right, simplifying the mechanism and control of the vacuum molding device. Note that the processes in Figures 6A and 6B correspond to Figures 4A and 4B, respectively. [Explanation of symbols]

[0034] 1. Transport container 10 Preform 11 Hinge part 11a Broken line part 12 Grasped part 13 Vacuum forming target part 14 Engagement portion 14a Entry 14a, 14b fitting portion 14c Hook part 14d Catch part 14e Claws 20 pedestal 21 Center 22 End 24 Notch 30 containers 41, 42 Frame 43-inch 44 Heater

Claims

1. a preform that is flat and rectangular in plan view, and has left and right vacuum forming target portions, left and right gripped portions in the form of closed curves that continuously surround the left and right vacuum forming target portions, a hinge portion that is sandwiched between the left and right gripped portions and crosses the preform in a straight line, and a plurality of engaging portions that are provided on the periphery of the preform on both sides of the hinge portion, the thickness of the hinge portion decreasing from the gripped portions on both sides adjacent to the hinge portion toward the center over its entire length, and a linear fold line portion that is thick enough to be manually bent is formed at the center, the preform being produced by injection molding; an upper frame body and a lower frame body having closed curved pressing surfaces surrounding the peripheries of the left and right vacuum forming target portions, respectively, sandwiching the left and right vacuum forming target portions from above and below while avoiding the hinge portion to insulate them from heat from the heater, and heating the vacuum forming target portions with the heater to vacuum form a convex shape; A manufacturing method for manufacturing a transport container by bending the base at the hinge portion and attaching the engaging portion to the base, which has notches on each of the intersecting surfaces.

2. A preform that is flat and rectangular in plan view, having left and right vacuum forming target portions, left and right gripped portions in the form of closed curves that continuously surround the left and right vacuum forming target portions, respectively, a hinge portion that is sandwiched between the left and right gripped portions and crosses the preform in a straight line, and a plurality of engaging portions that are provided around the preform on the peripheral side of the preform on both sides, sandwiching the hinge portion, and the hinge portion has a thickness that decreases from the adjacent gripped portions on both sides toward the center over its entire length, and a preform that has a straight fold line portion at the center that is thick enough to be bent manually, created by injection molding, an upper frame body and a lower frame body having pressing surfaces surrounding the peripheries of the left and right vacuum-forming target portions in the left and right gripped portions and covering the hinge portion, sandwiching the left and right gripped portions from above and below to insulate them from heat from the heater, and heating the vacuum-forming target portions with the heater to vacuum-form a convex shape; A manufacturing method for manufacturing a transport container by bending the base at the hinge portion and attaching the engaging portion to the base, which has notches on each of the intersecting surfaces.

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