Manufacturing method for transport trays

Abstract

Providing a manufacturing method for lightweight transport trays with excellent watertightness, load-bearing capacity, and dustproof properties. [Solution] A manufacturing method using a single thermoplastic resin plate, the resin plate comprising a bottom plate portion, a first side plate portion, a second side plate portion, a first upper edge forming portion, a first folded portion, a second upper edge forming portion, a second folded portion, a connecting piece portion, and a connecting band portion, the first side plate portion having a cut portion, the cut portion being larger than the thickness of the resin plate, the connecting band portion having a flexible processing portion at the base side, the first folded portion being folded outwards via the first upper edge forming portion and fused to the first side plate portion, and the second upper edge The process includes: folding the second folded portion towards the outer surface via the forming portion and fusing it to the second side plate portion; melting a first virtual line passing through the boundary line between the bottom plate portion and the first side plate portion to make the first side plate portion stand upright relative to the bottom surface portion and the joining piece portion stand upright relative to the second side plate portion; fusing the end face of the first side plate portion and the adjacent end face of the joining piece portion with the connecting band portion folded back from the root side; and fusing the connecting band portion to the outer surface of the second side plate portion.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a transport tray made of synthetic resin. [Background Art]

[0002] As a transport tray made of synthetic resin, for example, a configuration is disclosed that is formed of a single low-foam synthetic resin sheet, and has a bottom plate, and a front side plate, a rear side plate, a right side plate, and a left side plate that each stand upright from each side of the bottom plate and constitute a peripheral wall (see, for example, FIG. 1 of Patent Document 1).

[0003] According to the synthetic resin transport tray disclosed in FIG. 1 of the above-mentioned Patent Document 1, although it is lightweight and has certain watertightness, durability, and load-bearing capacity, it has a drawback that corners may tear from top to bottom when an excessive load is applied from above. In order to improve durability against such excessive loads, it is also possible to provide separate reinforcing corners and reinforcing frames on the upper part of the transport tray (see, for example, FIG. 7 of Patent Document 1).

[0004] However, providing separate reinforcing corners and reinforcing frames has problems in that it entails a significant increase in weight and an increase in the manufacturing cost of the reinforcing corners and reinforcing frames.

[0005] On the other hand, regarding the synthetic resin transport tray disclosed in FIG. 1 of the above-mentioned Patent Document 1, it is also conceivable to apply a configuration in which a laterally extending protruding portion is provided on the upper part of the upright side plate, the upper part of the side plate is folded outward, and the laterally extending protruding portion is further superposed on the adjacent side plate (see, for example, FIGS. 6 to 9 of Patent Document 2). [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent No. 6670210 [Patent Document 2] Patent No. 4143999 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, even if one attempts to apply the configuration disclosed in Figures 6 to 9 of Patent Document 2 to the configuration of the synthetic resin transport tray shown in Figure 1 of Patent Document 1, according to the configuration of Patent Document 2, the laterally extending protruding portion interferes when performing heat fusion to ensure watertightness, making heat fusion impossible. Therefore, the technology of Patent Document 2 cannot be applied to the technology of Patent Document 1.

[0008] This invention has been made in view of the above circumstances, and aims to provide a lightweight, watertight, and load-bearing transport tray made of synthetic resin, as well as a method for manufacturing the same, which is an excellent problem to be solved by this invention.

[0009] On the other hand, industries that use transport trays, such as the medical, food, and precision machinery manufacturing industries, require the ability to prevent dust and other particles from adhering to transport trays made of synthetic resin. To meet this demand, it is possible to provide an antistatic layer on both the front and back surfaces of the synthetic resin material. However, since the antistatic layer is only present on the front and back surfaces, the edges of the synthetic resin material cannot be protected from static electricity.

[0010] Therefore, even if the configuration disclosed in Figures 6 to 9 of Patent Document 2 could be applied to the configuration of the synthetic resin transport tray shown in Figure 1 of Patent Document 1, the end face of the synthetic resin, which is a material that cannot be antistatic, would be exposed on the upper edge of the corner of the tray, resulting in the drawback of incomplete antistatic properties.

[0011] Therefore, in addition to the above-mentioned problems, the present invention aims to provide an excellent synthetic resin transport tray that can also be prevented from becoming statically charged. [Means for solving the problem]

[0012] A method for manufacturing a transport tray using a single thermoplastic resin plate, wherein the thermoplastic resin plate has its upper surface as the inner surface and its lower surface as the outer surface, and comprises a bottom plate portion, first side plate portions continuous to the left and right of the bottom plate portion, second side plate portions continuous to the front and rear of the bottom plate portion, a first folded portion continuous to the outside of the first side plate portion via a first upper edge forming portion, a second folded portion continuous to the outside of the second side plate portion via a second upper edge forming portion, connecting pieces continuous to the left and right of the second side plate portion, the second upper edge forming portion and the second folded portion, and connecting band portions protruding to the front and rear of the first folded portion with a width smaller than the width of the first folded portion, wherein the first folded portion is provided with a notch to extend the length of the connecting band portion, the notch has a notch length greater than the thickness of the thermoplastic resin plate, and the base side of the connecting band portion has a flexible processing portion. A method for manufacturing a transport tray is provided as a means to solve the above problem, comprising: a first step of folding the first folded portion outward via the first upper edge forming portion and fusing it to the first side plate portion, and folding the second folded portion outward via the second upper edge forming portion and fusing it to the second side plate portion; a second step of melting a first virtual line passing through the boundary line between the bottom plate portion and the first side plate portion to make the first side plate portion stand upright relative to the bottom surface portion and the joining piece portion stand upright relative to the second side plate portion; a third step of fusing the end face of the first side plate portion and the adjacent end face of the joining piece portion with the connecting band portion folded back from the root side; and a fourth step of fusing the connecting band portion to the outer surface of the second side plate portion. [Brief explanation of the drawing]

[0013] [Figure 1] (a) A plan view showing a thermoplastic resin plate according to an embodiment of the present invention, (b) A partially enlarged cross-sectional view when the thermoplastic resin plate is a single layer, and (c) A partially enlarged cross-sectional view when the thermoplastic resin plate is laminated. [Figure 2] This is a plan view showing the state in which the first folded portion and the second folded portion of a thermoplastic resin plate according to an embodiment of the present invention have been folded back to the back side and fused together. [Figure 3]This is a perspective view showing the state in which heating is performed by the first heating means in the state shown in Figure 2. [Figure 4] This is a perspective view showing the state in which the first side plate is raised relative to the bottom plate in the condition shown in Figure 3. [Figure 5] (a) A partially omitted perspective view showing the connecting band in a curved state, and (b) a state in which it is heated by the second heating means. [Figure 6] (a) A partially omitted perspective view showing the second side plate in an upright position and (b) the connecting band welded to the second side plate. [Figure 7] This is a perspective view showing a transport tray according to an embodiment of the present invention. [Figure 8] (a) Partial cross-sectional view of AA in Figure 7, (b) Partial cross-sectional view of AA with the handle in the open position. [Modes for carrying out the invention]

[0014] An embodiment of the present invention provides a method for manufacturing a transport tray using a single thermoplastic resin plate, wherein the thermoplastic resin plate has its upper surface as the inner surface and its lower surface as the outer surface, and comprises a bottom plate portion, first side plate portions continuous to the left and right of the bottom plate portion, second side plate portions continuous to the front and rear of the bottom plate portion, a first folded portion continuous to the outside of the first side plate portion via a first upper edge forming portion, a second folded portion continuous to the outside of the second side plate portion via a second upper edge forming portion, connecting pieces continuous to the left and right of the second side plate portion, the second upper edge forming portion and the second folded portion, and connecting band portions protruding to the front and rear of the first folded portion with a width smaller than the width of the first folded portion, wherein the first folded portion is provided with a notch to extend the length of the connecting band portion, the notch has a notch length greater than the thickness of the thermoplastic resin plate, and the base side of the connecting band portion has a flexible processing portion. A first step involves folding the first folded portion outwards via the first upper edge forming portion and fusing it to the first side plate portion, and folding the second folded portion outwards via the second upper edge forming portion and fusing it to the second side plate portion, a second step of melting a first imaginary line passing through a boundary line between the bottom plate portion and the first side plate portion to erect the first side plate portion relative to the bottom surface portion and erect the joining piece portion relative to the second side plate portion; a third step of fusing an end surface of the joining piece portion adjacent to an end surface of the first side plate portion in a state where the connection band portion is folded back from a root side; a fourth step of fusing the connection band portion to an outer surface of the second side plate portion; (first configuration).

[0015] According to the first configuration, the connection band portion can be curved by forming the cut portion and the flexible processing portion, and as a result, it becomes possible to fuse the joining piece portion and an edge portion of the first side plate portion, and watertightness can be ensured. Then, by subsequently fusing the connection band portion to the second side plate portion, durability against a load that tears and separates the first side plate portion and the second side plate portion can be improved.

[0016] Furthermore, in the first configuration described above, the thermoplastic resin plate may be provided with antistatic layers on an upper surface and a lower surface, and in the fourth step, a distal end side of the connection band portion may be arranged without protruding from directly below the second folded portion (second configuration).

[0017] According to the second configuration, although the thermoplastic resin plate has the antistatic layers on the upper surface and the lower surface, the antistatic function of the edge surfaces is insufficient. By arranging the distal end side of the connection band portion without protruding from directly below the second folded portion, the edge surfaces do not protrude outward, adsorption of dust due to static electricity can be suppressed, and dust resistance can be improved.

[0018] Furthermore, in the first configuration or the second configuration described above, the thermoplastic resin plate is continuously provided with a handle portion via a groove at a position of the first folded portion opposite to a position adjacent to the first upper edge forming portion, or at a position of the second folded portion opposite to a position adjacent to the second upper edge forming portion, and at the end of the first step, a maximum opening angle of the handle portion with respect to the first side plate portion or the second side plate portion can be an acute angle (third configuration).

[0019] According to the third configuration described above, in addition to achieving the effects of the first or second configuration described above, a handle portion is formed continuously below the folded portion fused to the side plate portion, and since the maximum opening angle is acute, it is possible to stably place fingers on the handle portion, thereby improving the transport work. [Examples]

[0020] The method for manufacturing the transport tray T according to this embodiment will be described below. Note that the same or equivalent parts in the figures are denoted by the same reference numerals, and their descriptions will not be repeated. For the sake of clarity, the diagrams referenced below show simplified or schematic representations of the components, or some components are omitted. Furthermore, the dimensional ratios of the components shown in each diagram do not necessarily represent the actual dimensional ratios.

[0021] In the method for manufacturing a transport tray T according to an embodiment of the present invention, first, a thermoplastic resin plate P is used. This thermoplastic resin plate P can be, for example, a plate material made from polypropylene. The thermoplastic resin plate P may consist of a single layer p1 as shown in Figure 1(b), or it may have an antistatic layer p3 on both the front and back surfaces of a polypropylene layer p2 as shown in Figure 1(c). In this embodiment, a plate with an antistatic layer p3 on both the front and back surfaces of a polypropylene layer p2 as shown in Figure 1(c) is used.

[0022] The thermoplastic resin sheet P is constructed as shown below by press forming (see Figure 1(a)). Specifically, if we describe the thermoplastic resin sheet P as having the bottom as the front, the top as the rear, the surface visible in the plan view as the inner surface, and the back side as the outer surface, it has a bottom plate portion 10 located in the center, first side plate portions 11 continuous with the left and right sides of the bottom plate portion 10 via a first virtual line L1, second side plate portions 12 continuous with the front and back of the bottom plate portion 10 via a fourth virtual line L4, a first folded portion 15 continuous with the outside of the first side plate portion 11 via a second virtual line L2, a first upper edge forming portion 13, and a third virtual line L3 in sequence, and a second folded portion 16 continuous with the outside of the second side plate portion 12 via a fifth virtual line L5, a second upper edge forming portion 14, and a sixth virtual line L6 in sequence. Handle portions 17 are provided further forward and behind the second folded portion 16. A groove portion L7 is provided at the boundary between the second folded portion 16 and the handle portion 17.

[0023] Furthermore, the first side plate portion 11 has an inclined portion 11A that gradually reduces the front-to-back width from the bottom plate portion 10 and a straight portion 11B that maintains a constant width. The inclined portion 11A has an inclination angle of approximately 45° with respect to the first virtual line L1.

[0024] A connecting band portion 19 is provided along the edge at both the front and rear ends of the first folded portion 15. The width of the connecting band portion 19 is smaller than the width of the first folded portion 15. A notch 15A is provided in the first folded portion 15 from the base end position of the connecting band portion 19 to extend the length of the connecting band portion 19. The notch 15A has a length greater than the thickness of the thermoplastic resin plate P.

[0025] The base of the connecting band portion 19 has a flexible section 19A. The flexible section 19A is configured by arranging multiple grooves 190 extending in the width direction of the connecting band 19 in the longitudinal direction of the connecting band portion 19. The flexible section 19A makes it possible to bend the connecting band portion 19 in a U-shape from the inner side to the outer side. Since the cut portion 15A has a length greater than the thickness of the thermoplastic resin plate P, when the edge surfaces of the first side plate portion 11 and the first upper edge forming portion 13 and the first folded portion 15 continuous therewith are heat-fused to the edge surface of the joining piece portion 18, the connecting band 19 can be bent in a U-shape, thereby preventing the connecting band 19 from being heat-treated.

[0026] Connecting pieces 18 are provided continuously on the left and right sides of the second side plate portion 12, the second upper edge forming portion 14, and the second folded portion 16. An inclined portion 18A is provided at the base end of the connecting piece 18 (i.e., the side that is downward when assembled). The inclined portion 18A has an inclination angle of approximately 45° with respect to the first virtual line.

[0027] The inclined portion 11A of the first side plate portion 11 and the inclined portion 18A of the connecting piece portion 18 are joined at one end, and the inclined portion 11A and the inclined portion 18A form a V-shaped contour in plan view.

[0028] In this embodiment, notches 16A are provided at both ends of the second folded portion 16. The notches 16A are shaped to prevent the second folded portion 16 from overlapping with the tip of the connecting band portion 19.

[0029] A method for manufacturing a transport container using a single thermoplastic resin sheet P having the above configuration will be described.

[0030] Using the second and third virtual lines shown in Figure 1 as a reference, the thermoplastic resin plate P is folded in a mountain fold, and the left and right first folded portions 15 are fused to the back side of the first side plate portion. Similarly, using the fifth and sixth virtual lines as a reference, the thermoplastic resin plate P is folded in a mountain fold, and the front and rear second folded portions 16 are fused to the back side of the second side plate portion. As a result, as shown in Figure 2, the first folded portion 15 and the second folded portion 16 are folded and fixed to the back side.

[0031] Next, as shown in Figure 3, a first heating means is used to form a groove having a V-shaped cross-sectional contour in the first virtual line L1, while simultaneously melting the groove. Then, the first side plate is raised relative to the bottom plate 10, and the joining piece 18 is raised relative to the second side plate 12. This closes the molten groove. As this area cools and solidifies, the first side plate remains upright relative to the bottom plate 10, and the joining piece 18 remains upright relative to the second side plate 12 (see Figure 4).

[0032] Next, as shown in Figure 5(a), the connecting band is curved from the side with the flexible edge (root side). Since a notch 15A is formed in the first folded portion to extend the length of the connecting band, the position of the root side of the connecting band can be moved back. In other words, the front edge (or rear edge) of the first side plate portion protrudes more than the curved connecting band portion due to the formation of the notch. As a result, the connecting band portion can be positioned so that it is not affected by heat during the heat treatment when the second side plate portion is erected in the next step.

[0033] The curved state of the connecting band can be maintained by using a jig (not shown) that clamps the connecting band together with the first side plate and the first folded portion, or the worker can hold the connecting band and the first side plate together with their fingers.

[0034] Then, as shown in Figure 5(b), a second heating means is used to melt the first side plate portion, the first folded portion, and the joining piece portion, and a groove portion having a V-shaped cross-sectional contour is formed in the fourth virtual line in a molten state. As described above, the curved connecting band portion does not melt.

[0035] As shown in Figure 6, the second side plate is raised relative to the bottom plate 10. This closes the molten groove, and the first side plate and the first folded portion are fused to the joining piece and the second folded portion. As these parts cool and solidify, the second side plate remains upright relative to the bottom plate 10.

[0036] Next, the outer surface of the connecting band when curved is heat-treated, and the molten surface of the connecting band is fused to the second side plate (see Figure 6(b)). The tip of the fused connecting band is positioned directly below the notch in the second folded portion, without protruding from directly below it.

[0037] The transport tray is thus completed (see Figure 7). The completed transport tray according to this embodiment has its corners reinforced by connecting bands and is durable against loads from above, particularly loads that would cause the fused first and second side plates to tear. Since the connecting bands are formed by extending from a part of the first folded portion 15, lightness can be ensured compared to cases where a separate heavy reinforcing member is used.

[0038] Furthermore, in the completed transport tray according to this embodiment, the first upper edge forming portion and the second upper edge forming portion are formed continuously at the upper edge. Since an antistatic layer is visible on the surface of the first upper edge forming portion and the second upper edge forming portion, dust and other particles will not adhere to the upper edge surface of the transport tray, resulting in excellent dust resistance.

[0039] Although the antistatic layer is hardly visible on the edges of the connecting band, since this connecting band is located directly below the first and second folded sections, dust and other debris cannot adhere to it from above, thus ensuring dustproof properties.

[0040] Furthermore, as shown in Figures 8(a) and 8(b), a partial cross-section of AA in Figure 7, the handle portion has an acute maximum opening angle α relative to the second side plate. This allows for a secure grip on the handle, resulting in improved transport efficiency. [Explanation of Symbols]

[0041] L1 First virtual line L2 Second Virtual Line L3 Third Virtual Line L4 4th virtual line L5 Fifth Virtual Line L6, the 6th virtual line L7 groove P Thermoplastic resin plate p1 Single layer p2 Polypropylene layer p3 Antistatic layer T Transport Tray 10 Bottom plate part 11 First side plate part 12 Second side plate part 13 First upper edge forming part 14 Second upper edge forming part 15 1st turning section 15A notch 16 Second turning section 16A Notch 17 Handle section 18 Joint piece 19 Connection section 19A Flexible Processing Unit 190 Groove 20 First heating means 21 Second heating means

Claims

1. A method for manufacturing a transport tray using a single thermoplastic resin sheet, The thermoplastic resin plate has its upper surface as the inner surface and its lower surface as the outer surface. The thermoplastic resin plate is The base plate and, The first side plate portion is continuous with the left and right sides of the bottom plate portion, A second side plate portion is continuous with the front and rear of the aforementioned bottom plate portion, A first folded portion is provided on the outside of the first side plate portion, via a first upper edge forming portion, A second folded portion is provided on the outside of the second side plate portion, via a second upper edge forming portion, The second side plate portion, the second upper edge forming portion, and the second folded portion have connecting pieces that are continuous on the left and right sides, The first folded portion is provided with connecting bands that protrude from the front and rear of the first folded portion with a width smaller than the width of the first folded portion, The first folded portion is provided with a notch to extend the length of the connecting band portion, The cut portion has a cut length that is greater than the thickness of the thermoplastic resin plate. The base of the aforementioned connecting band has a flexible section, The first step involves folding the first folded portion outwards via the first upper edge forming portion and fusing it to the first side plate portion, and folding the second folded portion outwards via the second upper edge forming portion and fusing it to the second side plate portion, A second step involves melting a first virtual line passing through the boundary line between the bottom plate portion and the first side plate portion to raise the first side plate portion relative to the bottom surface portion and raise the joining piece portion relative to the second side plate portion, A third step involves folding the connecting band portion back from the root side and fusing the end face of the first side plate portion with the end face of the adjacent joining piece portion, A fourth step involves fusing the connecting band portion to the outer surface of the second side plate portion, A method for manufacturing a transport tray, characterized by having [a certain feature].

2. The thermoplastic resin plate is provided with an antistatic layer on its upper and lower surfaces. The method for manufacturing a transport tray according to claim 1, wherein in the fourth step, the tip of the connecting band portion is positioned so as not to protrude from directly below the second folded portion.

3. The thermoplastic resin plate is provided with a handle portion continuously connected via a groove at a position in the first folded portion that is opposite to the position adjacent to the first upper edge forming portion, or at a position in the second folded portion that is opposite to the position adjacent to the second upper edge forming portion. A method for manufacturing a transport tray according to claim 1 or 2, characterized in that at the end of the first step, the maximum opening angle of the handle portion relative to the first side plate portion or the second side plate portion is an acute angle.

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