Resin-made double container

Abstract

To provide a resin-made double container capable of improving the bonding strength between an outer container and an inner container.SOLUTION: The present invention relates to a resin-made double container 10 in which an inner container 30 is fitted into an outer container 20 made of resin having an opening edge 21 on the upper surface, and the outer container and the inner container are welded together along the circumferential direction at a joined part 40, the joined part being located below the opening edge, the outer container having an outer joining surface 23 on the inner surface side at the joined part, and the inner container having an inner joining surface 37 on the outer surface side at the joined part, the outer joining surface and the inner joining surface having a tapered shape sloping from top to bottom, the inner diameter of the outer joining surface at the joined part being smaller than the outer diameter of the inner joining surface, and the outer joining surface and the inner joining surface abutting on each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a resin double container formed by welding an inner container and an outer container.

Background Art

[0002] A resin double container in which an outer container is welded to the exterior of a resin inner container for containing liquids and the like is known. For example, in Patent Document 1, an inclined surface protruding outward is provided at the upper edge of the inner container, and the inclined surface is laser welded to the upper end surface of the outer container.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The outer container and the inner container are each produced by resin molding. In resin molding, roughness is likely to occur particularly on the end surfaces, and dimensional variations are also likely to occur. For this reason, the upper end surface of the outer container does not adhere closely to the inclined surface of the inner container, the contact becomes unstable, and non-welded portions may occur at the joint. If there are non-welded portions, liquids such as water may enter between the outer container and the inner container.

[0005] In addition, in order to enhance the heat insulation property of the double container, an intermediate space is hermetically formed between the outer container and the inner container, and a gas having a low thermal conductivity such as krypton gas or argon gas is enclosed in the intermediate space, or the intermediate space is depressurized, so that the intermediate space functions as a heat insulation space. However, if there are non-welded portions at the joint between the outer container and the inner container as described above, the airtightness of the intermediate space cannot be maintained, and the heat insulation performance cannot be exhibited.

[0006] An object of the present invention is to provide a resin double container capable of enhancing the joinability between an outer container and an inner container.

Means for Solving the Problem

[0007] The resin double container according to the present invention is a resin double container in which an inner container is fitted into a resin outer container having an opening edge on the upper surface, and which has a joint portion where the outer container and the inner container are welded and joined along the circumferential direction, the joint portion is provided below the opening edge, the outer container has an outer joint surface on the inner surface side at the joint portion, the inner container has an inner joint surface on the outer surface side at the joint portion, the outer joint surface and the inner joint surface are in a tapered shape inclined downward from top to bottom, at the joint portion, the inner diameter of the outer joint surface is smaller than the outer diameter of the inner joint surface, and the outer joint surface and the inner joint surface are in contact.

[0008] the outer joint surface has a straight vertical cross-section, the inner joint surface can have a curved shape that bulges outward in the vertical cross-section.

[0009] the inner surface of the outer container has a vertical cross-section above the outer joint surface that extends vertically to the opening edge, the outer surface of the inner container can have a vertical cross-section of the portion facing the outer container above the inner joint surface.

[0010] the inner container can have an umbrella portion that covers the upper side of the opening edge of the outer container.

[0011] the outer joint surface and the inner joint surface can be shaped to have a reduced diameter from top to bottom.

[0012] the outer joint surface and the inner joint surface can be shaped to have a reduced diameter from bottom to top.

[0013] the outer container and the inner container can have a circular cross-section.

[0014] The outer container and the inner container can have a polygonal cross-section.

Advantages of the Invention

[0015] According to the resin double container of the present invention, since the outer joint surface of the outer container and the inner joint surface of the inner container are tapered and dimensioned to overlap in the radial direction, when the outer container is fitted onto the inner container, the inner joint surface is pressed against the outer joint surface. In this state, by performing laser irradiation from the outside of the outer container toward the outer joint surface and the inner joint surface, welding can be performed without problems even if there are some dimensional variations. Further, since the welding of the outer joint surface and the inner joint surface is performed below the opening edge of the outer container, even if there is roughness at the opening edge of the outer container, it does not affect the welding.

[0016] Therefore, by joining the outer container and the inner container, an airtight intermediate space can be formed between the outer container and the inner container. By enclosing a gas with a low thermal conductivity or reducing the pressure in the intermediate space, the intermediate space can be made to function as a heat insulating space, and a resin double container with high heat insulating performance can be provided.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the resin double container 10 of the present invention will be described with reference to the drawings.

[0019] FIG. 1 is a front view showing the appearance of a resin double container 10 according to an embodiment of the present invention. As shown in the figure, the resin double container 10 is formed by fitting a resin inner container 30 into a resin outer container 20 having an open upper portion, and welding the outer container 20 and the inner container 30 in the circumferential direction at a joint portion 40.

[0020] Both the outer container 20 and the inner container 30 can be manufactured by injection molding or blow molding of a thermoplastic resin. Examples of the thermoplastic resin include, but are not limited to, polypropylene resin (PP) and polyethylene terephthalate resin (PET). In order to preferably join the outer container 20 and the inner container 30, it is desirable to employ a resin material having the same melting point. Therefore, it is preferable that the outer container 20 and the inner container 30 use the same resin material.

[0021] The resin material may be either a soft resin or a hard resin. For example, by making the outer container 20 a soft resin and the inner container 30 a hard resin, the tactile sensation when the user grasps the outer container 20 serving as the exterior of the resin double container 10 can be enhanced, and since the inner container 30 is not crushed, it is possible to prevent the contained contents from spilling out.

[0022] The resin material may be transparent or may be colored. Of course, only the outer container 20 may be colored, only the inner container 30 may be colored, or the outer container 20 and the inner container 30 may be colored differently.

[0023] The wall thicknesses of the outer container 20 and the inner container 30 are not particularly limited as long as they can be welded to each other. For example, the wall thickness of the outer container 20 is about 1 mm to 3 mm, and the wall thickness of the inner container 30 is about 0.5 mm to 2 mm. In the illustrated embodiment, the wall thickness of the outer container 20 is formed thicker than that of the inner container 30. Of course, the wall thicknesses of the outer container 20 and the inner container 30 may be the same or the wall thickness of the inner container 30 may be thicker.

[0024] The outer container 20 is a cylindrical body having an opening edge 21 with an open upper portion, and can be formed of, for example, a soft resin. In the embodiments shown in FIGS. 1 to 3, the outer container 20 is a cylindrical body with a bottom. In the resin double container 10 shown in FIG. 7 described later, the outer container 20 has a bottomed cylindrical form in which an outer bottom surface 26 is joined to a cylindrical outer barrel portion 24.

[0025] As a specific embodiment, as shown in FIG. 3(a), the outer container 20 has a tapered shape immediately below the upper opening edge 21, and the inner surface side of the tapered shape serves as an outer joint surface 23 that is welded to the inner container 30. The outer joint surface 23 will be described later.

[0026] Below the outer joint surface 23, the outer container 20 has an outer barrel portion 24 with a diameter larger than that of the outer joint surface 23. The outer barrel portion 24 is formed with a diameter larger than that of the inner barrel portion 39 of the inner container 30. An intermediate space 28 is formed between the outer barrel portion 24 and the inner barrel portion 39 to enhance the heat insulation property. In the illustration, the outer barrel portion 24 has a form in which a plurality of stepped portions are formed, and the lower portion is closed by an outer bottom surface 26 continuous with the outer barrel portion 24. The outer bottom surface 26 of the outer container 20 has a shape that stabilizes the resin double container 10 when placed on a table or the like. When the outer container 20 is formed of a soft resin, in order to reinforce the outer bottom surface 26, it is desirable to accommodate a bowl-shaped reinforcing member 27 inside the bottom of the outer container 20 as shown in FIGS. 2 and 3.

[0027] The inner container 30 is a bottomed cylindrical container that is accommodated in the outer container 20 and has an accommodation space 31 for accommodating contents such as a liquid. The inner container 30 can be formed of a hard resin.

[0028] The inner container 30 can be configured to have a mouth portion 32 at the upper end through which the contents are put in and taken out. In the illustrated embodiment, a spiral thread 33 to which a cap can be attached is formed on the outer periphery of the mouth portion 32.

[0029] As shown in FIG. 3(b), the inner container 30 can be configured to have a shoulder portion 34 whose diameter expands outward below the mouth portion 32. The lower part of the shoulder portion 34 is inclined in a tapered shape and serves as an inner joint surface 37 that is welded to the outer joint surface 23 of the outer container 20 described above. The inner joint surface 37 will be described later.

[0030] As shown in FIG. 4, the lower surface of the shoulder portion 34 constitutes an umbrella portion 35 that covers the upper side of the opening edge 21 of the outer container 20 when the inner container 30 is fitted into the outer container 20. The umbrella portion 35 is formed to have an outer diameter slightly larger than the outer diameter of the opening edge 21, and the lower surface is substantially horizontal. By providing the umbrella portion 35, the opening edge 21 of the outer container 20 is not exposed. Therefore, even if there is roughness on the opening edge 21 of the outer container 20 due to resin molding, the user will not touch it and the finger will not get caught.

[0031] As a specific embodiment, as shown in FIG. 3(b), the inner container 30 can be configured such that the diameter gradually decreases below the inner joint surface 37 and is connected to the inner barrel portion 39. The inner barrel portion 39 has a cylindrical shape without unevenness or a shape without unevenness, so that the retention and residue of the contents in the inner barrel portion 39 can be reduced. The lower end of the inner barrel portion 39 is closed by an inner bottom surface 391. The inner bottom surface 391 is hemispherical in the illustration.

[0032] Since the inner container 30 is inserted from the opening edge 21 of the outer container 20 and is accommodated in the outer container 20 as shown in FIG. 2, it is desirable that the outer diameters of the inner barrel portion 39 and the inner bottom surface 391 be formed smaller than the minimum inner diameter of the outer joint surface 23.

[0033] In this embodiment, as shown in FIG. 2, the outer container 20 and the inner container 30 are of a suspended type in which the outer cylinder portion 24 and the outer bottom surface 26 below the joint portion 40 do not contact the inner cylinder portion 39 and the inner bottom surface 391. As a result, an intermediate space 28 can be formed below the joint portion 40 between the outer container 20 and the inner container 30. The intermediate space 28 can be made into a heat insulation space by enclosing or depressurizing a gas with a low thermal conductivity as an airtight space by the joint portion 40. Note that the gas with a low thermal conductivity can also be enclosed in a depressurized state.

[0034] The outer joint surface 23 of the outer container 20 and the inner joint surface 37 of the inner container 30 described above will be described in detail.

[0035] As shown in FIG. 2, the outer container 20 and the inner container 30 are inserted with the inner cylinder portion 39 of the inner container 30 into the opening edge 21 of the outer container 20, and the resin double container 10 is formed by laser welding the outer joint surface 23 and the inner joint surface 37 that come into contact with each other as shown in FIG. 4. Note that the portion where the outer joint surface 23 and the inner joint surface 37 are welded together is referred to as a joint position 41 (see FIGS. 4 to 6).

[0036] The outer joint surface 23 and the inner joint surface 37 serving as the joint surfaces are shown in FIG. 5. FIG. 5(a) is an enlarged view of the outer joint surface 23 of the outer container 20, and FIG. 5(b) is an enlarged view of the inner joint surface 37 of the inner container 30. The outer container 20 has an outer vertical cylinder portion 22 extending vertically downward from the opening edge 21, and the lower part of the outer vertical cylinder portion 22 is an outer joint surface 23 whose diameter is reduced in an oblique direction in a tapered shape. The outer joint surface 23 can be, for example, a linear surface whose longitudinal section is reduced in diameter in an oblique direction from top to bottom. The outer joint surface 23 is formed such that the inner diameter R1 at the joint position 41 before fitting the inner container 30 into the outer container 20 is smaller than the outer diameter R2 of the inner joint surface 37 described below. For example, when the tolerance of the outer container 20 is 0 mm to -1 mm and the tolerance of the inner container 30 is 0 mm to 1 mm, it is desirable to adjust the inner diameter R1 of the outer joint surface 23 to be smaller than the outer diameter R2 of the inner joint surface 37 by about 0 mm to 2 mm.

[0037] As shown in Fig. 5(b), the inner joint surface 37 has an inner vertical cylinder portion 36 that extends vertically downward from the umbrella portion 35 of the shoulder portion 34. Below the inner vertical cylinder portion 36, the inner joint surface 37 is tapered and has a reduced diameter in an oblique direction. The inner joint surface 37 has a bulging portion 38 that bulges outward in a curved shape at the joint position 41, and the outer diameter R2 of the bulging portion 38 is formed to be larger than the inner diameter R1 of the above-described outer joint surface 23. Note that it is desirable that the outer diameter of the inner vertical cylinder portion 36 is smaller than the inner diameter of the outer vertical cylinder portion 22, so that a gap is formed between the inner vertical cylinder portion 36 and the outer vertical cylinder portion 22. This is to reduce the contact area between the outer container 20 and the inner container 30 and suppress heat transfer.

[0038] Note that the joint position 41 may vary up and down due to the tolerances of the outer container 20 and the inner container 30, or the tolerance of the laser irradiation position, etc. Therefore, preferably, the outer diameter of the bulging portion 38 is formed to be larger than the inner diameter of the outer joint surface 23 with a margin above and below the joint position 41, and it is preferable to have a margin width W (see Fig. 4) at the joint position 41. Specifically, it is desirable that the bulging portion 38 bulges outward in a range of about 0.5 mm to 5 mm above and below the joint position 41 respectively.

[0039] To assemble the resin double container 10 from the outer container 20 and the inner container 30 having the above-described configuration, first, as shown in Fig. 2, the inner container 30 is inserted into the opening edge 21 of the outer container 20 from the inner bottom surface 391 side. As a result, the inner cylinder portion 39 and the inner bottom surface 391 enter the outer cylinder portion 24. Then, by further pushing the inner container 30 in this state, the outer joint surface 23 and the inner joint surface 37 come into contact. Fig. 6 shows a state where the outer joint surface 23 and the inner joint surface 37 are in contact. In the figure, as shown by the shaded portion B, the inner joint surface 37 contacts the outer joint surface 23 in a range including at least the bulging portion 38 including the joint position 41 and its upper and lower portions. Also, the umbrella portion 35 of the inner container 30 covers the upper part of the opening edge 21 of the outer container 20 so that the opening edge 21 is not exposed.

[0040] In this embodiment, since both the outer joint surface 23 and the inner joint surface 37 are tapered so as to reduce the diameter from top to bottom, when the inner container 30 is inserted into the outer container 20, the outer joint surface 23 and the inner joint surface 37 surely come into contact with each other. Further, since the outer joint surface 23 and the inner joint surface 37 can be aligned in the circumferential direction, even if there is a core deviation in the posture of the inner container 30 with respect to the outer container 20, the posture becomes stable during the insertion of the inner container 30, so that the outer joint surface 23 and the inner joint surface 37 suitably come into contact with each other. Further, since the outer container 20 is provided with an outer vertical cylindrical portion 22 above the outer joint surface 23, and the inner container 30 is provided with an inner vertical cylindrical portion 36 (see FIG. 4) above the inner joint surface 37, as shown in FIG. 6, when the outer container 20 is inserted into the inner container 30, the outer vertical cylindrical portion 22 guides the inner vertical cylindrical portion 36 in the vertical direction, so that there is an advantage that the inclination of the posture of the inner container 30 can be corrected.

[0041] In this state, a laser is irradiated from the outside of the outer container 20 so as to go around along the joining position 41. Examples of the laser include an infrared laser and a semiconductor laser. The beam diameter of the laser is preferably 0.5 mm to 3 mm in diameter, but is not limited thereto. By laser irradiation, as shown in FIG. 4, the outer joint surface 23 and the inner joint surface 37 are welded and joined to form a joint portion 40. Since the outer joint surface 23 and the inner joint surface 37 are in contact with each other in the upper and lower ranges including the joining position 41 (hatched portion B in FIG. 6), even if the irradiation position of the laser is slightly shifted up and down, welding and joining can be surely performed. The laser can surely weld and join the outer joint surface 23 and the inner joint surface 37 without a gap by irradiating while pressing the outer joint surface 23 toward the inner joint surface 37 with a workpiece (not shown).

[0042] In this embodiment, the outer joint surface 23 has a linear tapered shape. Thereby, when laser irradiation is performed, diffusion of the laser light is prevented, and welding quality can be ensured. Further, the irradiation direction of the laser is set to a direction perpendicular to the outer joint surface 23 as shown by an arrow L in FIG. 6 (in the drawing, the laser is irradiated from an obliquely downward direction), so that diffusion of the laser light can be suppressed, and suitable welding can be performed.

[0043] Before laser bonding, it is desirable to enclose a gas with low thermal conductivity, such as krypton gas or argon gas, in the intermediate space 28 between the outer container 20 and the inner container 30 formed below the bonding position 41, or to keep the intermediate space 28 under reduced pressure. Note that the gas with low thermal conductivity can also be enclosed in a reduced-pressure state. Thereby, when the outer bonding surface 23 and the inner bonding surface 37 are laser welded, the intermediate space 28 can function as an airtight heat-insulating space. The enclosed gas or the reduced-pressure state causes the outer bonding surface 23 and the inner bonding surface 37 to be in airtight contact due to the self-weight of the inner container 30 when the outer container 20 is fitted onto the inner container 30. Therefore, it is almost impossible for the gas to leak from the intermediate space 28 or for the reduced pressure to be released during laser irradiation. However, if there is a possibility of these occurrences, laser irradiation may be performed while the inner container 30 is press-fitted into the outer container 20, or laser irradiation may be performed in the space filled with the gas or in the reduced-pressure space.

[0044] By the above laser irradiation, the outer container 20 and the inner container 30 are welded and joined at the joint portion 40, thereby producing the resin double container 10 as shown in FIGS. 1 and 2. By hermetically joining the outer bonding surface 23 and the inner bonding surface 37 at the joint portion 40, the intermediate space 28 can function as an airtight heat-insulating space, and heat retention and cold retention of the contents of the inner container 30 can be achieved. Also, in the case of cold contents, condensation on the outer container 20 can be prevented. Further, since the temperature of the contents is difficult to be transmitted to the outer container 20, overheating and overcooling of the outer container 20 can be prevented.

[0045] In the present invention, the outer container 20 and the inner container 30 do not contact each other below the joint portion 40, and the inner container 30 is supported by the outer container 20 in a state of being suspended at the joint portion 40. For this reason, in the portion below the joint portion 40, heat is not directly transmitted from the outer container 20 to the inner container 30 or from the inner container 30 to the outer container 20, so that the heat-insulating performance can be further enhanced. Also, due to the presence of the intermediate space 28, deformation of the inner container 30 when the user grasps the outer container 20 can be reduced.

[0046] FIG. 7 is a cross-sectional view of a resin double container 10 showing different embodiments of the present invention. Explanation of parts overlapping with the above embodiments will be omitted as appropriate.

[0047] The resin double container 10 in FIG. 7 has a tapered shape (a tapered shape that expands in diameter from top to bottom) in which the outer joint surface 23 and the inner joint surface 37 are reduced in diameter from bottom to top. Specifically, the outer joint surface 23 has an inclined tapered shape that linearly reduces in diameter from bottom to top. Further, the inner joint surface 37 has a tapered shape that reduces in diameter from bottom to top and has a bulging portion 38 that bulges outward in a curved shape. The inner container 30 has a mouth portion 32 formed on the inner joint surface 37.

[0048] In the present embodiment, both the outer container 20 and the inner container 30 have a cylindrical shape that bulges so that the outer barrel portion 24 and the inner barrel portion 39 become thicker. Therefore, the inner container 30 cannot be inserted from the opening edge 21 of the outer container 20. For this reason, the outer container 20 has an open state at the lower surface of the outer barrel portion 24. Thereby, before welding the outer bottom surface 26, with the opening edge 21 of the outer container 20 facing downward and the mouth portion 32 of the inner container 30 facing downward, the inner container 30 is inserted into the outer container 20 from the opening at the bottom side of the outer container 20, and by its own weight or by pushing the inner container 30 toward the opening edge 21 of the outer container 20, the outer joint surface 23 and the inner joint surface 37 can be strongly adhered, and suitable airtight laser welding can be performed.

[0049] And after laser welding the outer joint surface 23 and the inner joint surface 37, the outer bottom surface 26 may be welded and joined 42 to the outer barrel portion 24. By performing this welding in a gas environment with low thermal conductivity or in a reduced pressure environment, the intermediate space 28 between the outer container 20 and the inner container 30 can be made into a heat insulating space.

[0050] The resin double container 10 in FIG. 7 has a thinner upper side where the mouth portion 32 is formed, so that the area around the mouth portion 32 (above the joint portion 40) that deviates from the intermediate space 28, which is a heat insulating space, can be reduced, and the heat insulating effect can be enhanced.

[0051] In the above embodiments, the cross-sections of the outer container 20 and the inner container 30 are all circular, but they may also be elliptical or the like, and these shapes may also be polygonal shapes such as quadrilaterals or rounded quadrilaterals. Furthermore, the cross-section of the outer container 20 may be polygonal, and the cross-section of the inner container 30 may be circular. Of course, the outer container 20 and the inner container 30 may each have a combination of a polygonal cross-section and a circular cross-section.

Example

[0052] Figs. 8 to 10 are explanatory views showing an embodiment of an assembling apparatus 50 and an assembling process for laser-welding the outer container 20 and the inner container 30 of the resin double container 10 described with reference to Figs. 1 to 6. In this embodiment, the assembly of the resin double container 10 in which krypton gas is enclosed in the intermediate space 28 will be described. Since the reference numerals of the respective members of the outer container 20 and the inner container 30 constituting the resin double container 10 are omitted, please refer to Figs. 1 to 6 as appropriate. Also, the movable parts such as the plunger described below can be constituted by known actuators, links, motors, gears, etc., and the detailed description and illustration of their mechanisms etc. are omitted.

[0053] The assembling apparatus 50 can be configured such that an inner container holding mechanism 60 for holding the inner container 30 and an outer container holding mechanism 70 for holding the outer container 20 are arranged vertically.

[0054] As shown in Fig. 8(a), the inner container holding mechanism 60 includes a mouth holder 61 for holding the mouth portion 32 of the inner container 30 and an umbrella portion holder 64 for holding the umbrella portion 35. The mouth holder 61 and the umbrella portion holder 64 are short cylindrical shapes opening downward, and the mouth holder 61 has a screw groove 62 (see Fig. 10(f)) that fits into a screw 33 formed on the outer periphery of the mouth portion 32. Also, the umbrella portion holder 64 has an inward claw 641 that fits under the umbrella portion 35 of the inner container 30.

[0055] The mouth holder 61 is rotatably arranged by a rotation mechanism (not shown). By rotating the mouth holder 61 and screwing it onto the screw 33 of the mouth part 32, the mouth holder 61 engages with the mouth part 32. Further, when the mouth part 32 enters the mouth holder 61, the inner container 30 is lifted by the screw thrust, and the umbrella part 35 fits into the claw 641 of the umbrella holder 64.

[0056] The mouth holder 61 is arranged to be vertically movable via the inner container press-in plunger 63. The inner container press-in plunger 63 is arranged in an airtight formation jig 65 that covers the mouth holder 61. The airtight formation jig 65 has a flange part 66 that spreads toward the outer periphery, and can move up and down within a cylindrical guide 69. A groove 67 is formed in the flange part 66, into which the upper edge of the airtight formation surrounding cylinder 73 of the outer container holding mechanism 70 fits airtightly. A packing is laid in the groove 67. The airtight formation jig 65 is connected to be vertically movable to a jig lifting and lowering plunger 68 arranged at the upper part.

[0057] The outer container holding mechanism 70 has a bottomed cylindrical outer container holder 71 that holds the outer container 20 and has an open upper part, and a cylindrical airtight formation surrounding cylinder 73 that fits on the outer periphery of the outer container holder 71 and can slide up and down with respect to the outer container holder 71. The outer container holder 71 holds the outer container 20 and is equipped with a rotation mechanism (not shown) that rotates the outer container 20 during laser irradiation. The airtight formation surrounding cylinder 73 fits airtightly on the outer periphery of the outer container holder 71 via an annular seal member 72, and can move up and down the outer periphery of the outer container holder 71 by a surrounding cylinder lifting and lowering plunger (indicated by arrow C in Fig. 8(b)).

[0058] Near the upper edge of the airtight formation surrounding cylinder 73, a decompression hole 74 and an air supply hole 75 are provided. A decompression mechanism (not shown) such as a decompression pump is connected to the decompression hole 74, and an air supply mechanism (not shown) that supplies a gas with a low thermal conductivity such as krypton gas is connected to the air supply hole 75.

[0059] Further, as shown in FIG. 10(e), a laser irradiator 80 for irradiating a laser to the joining position 41 between the outer container 20 and the inner container 30 is arranged.

[0060] The assembling process of the resin double container 10 of the present embodiment can be composed of six processes shown in FIGS. 8(a)-(b), 9(c)-(d), and 10(e)-(f).

[0061] FIG. 8(a) is a process of setting the inner container 30 and the outer container 20. As shown in the figure, the inner container 30 is set in the inner container holding mechanism 60, and the outer container 20 is set in the outer container holding mechanism 70, respectively. Note that FIG. 8(a) shows a state where the lower part of the inner container 30 has already entered from the opening edge 21 of the outer container 20.

[0062] Specifically, as shown in FIG. 8(a), the mouth part 32 of the inner container 30 is fitted into the mouth part holder 61 of the inner container holding mechanism 60, and while fixing the inner container 30 in the rotational direction, the mouth part holder 61 is rotated clockwise. Thereby, the mouth part 32 is screwed into the mouth part holder 61, and the inner container 30 rises by the screw thrust, and the umbrella part 35 fits into the claw 641 of the umbrella part holder 64, and the inner container 30 is set in the inner container holding mechanism 60. The mouth part holder 61 and the umbrella part holder 64 are held at the upper position of the airtight formation jig 65 by the inner container press-in plunger 63, and the airtight formation jig 65 is moved upward in the guide 69 by the jig lifting plunger 68.

[0063] The outer container 20 is also set in the outer container holding mechanism 70 by housing it in the outer container holder 71 so that the opening edge 21 faces upward in a state where the airtight formation surrounding cylinder 73 is slid downward with respect to the outer container holder 71, as shown in FIG. 8(a).

[0064] Subsequently, as shown in Fig. 8(b), the jig lifting plunger 68 of the inner container holding mechanism 60 is actuated to push the airtight forming jig 65 downward (downward arrow D in the figure), and the surrounding cylinder lifting plunger of the outer container holding mechanism 70 (upward arrow C in the figure) is actuated to move the airtight forming surrounding cylinder 73 upward with respect to the outer container holder 71. As a result, the upper edge of the airtight forming surrounding cylinder 73 fits into the groove 67 of the airtight forming jig 65, and the inside of the outer container holding mechanism 70 is hermetically closed. On the other hand, since the inner container pressing plunger 63 holds the mouth holder 61 at the upper position of the airtight forming jig 65, the inner container 30 enters the outer container 20, but the inner joint surface 37 remains at a position above the opening edge 21 of the outer container 20. Thus, the inner joint surface 37 and the outer joint surface 23 do not contact each other, and a gap communicating with the intermediate space 28 is formed therebetween, allowing the entry and exit of gas.

[0065] In the state of Fig. 8(b), the pressure reducing mechanism is actuated to discharge air from the pressure reducing hole 74 to reduce the pressure inside the outer container holding mechanism 70. As a result, the pressure inside the intermediate space 28 is also reduced. Then, in the state where the pressure has been reduced, the air supply mechanism is actuated to fill the inside of the outer container holding mechanism 70 with krypton gas from the air supply hole 75, so that the krypton gas flows into the intermediate space 28. Note that the outer container holding mechanism 70 may be filled with krypton gas in a reduced pressure state.

[0066] From this state, as shown by the downward arrow E in Fig. 9(c), the inner container pressing plunger 63 is actuated to push the inner container 30 downward until the inner joint surface 37 of the inner container 30 contacts the outer joint surface 23 of the outer container 20. As a result, as shown by the shaded portion B in Fig. 6, the inner joint surface 37 and the outer joint surface 23 contact hermetically, and the intermediate space 28 is filled with krypton gas or filled in a reduced pressure state.

[0067] While keeping the inner joint surface 37 and the outer joint surface 23 in airtight contact, as shown in Fig. 9(d), operate the enclosure cylinder lifting plunger (downward arrow F in the figure) to slide the airtight forming enclosure cylinder 73 downward. Since the inner joint surface 37 and the outer joint surface 23 are pressed airtightly by the inner container press-fitting plunger 63, the krypton gas filled in the intermediate space 28 will not flow out to the outside. By sliding the airtight forming enclosure cylinder 73 downward, the joint position 41 is exposed.

[0068] Next, rotate the mouth holder 61 and the outer container holder 71 in the same direction, and while rotating the inner container 30 and the outer container 20 integrally, irradiate the joint position 41 with a laser as shown in Fig. 10(e) (right arrow L in the figure). Note that the irradiation direction of the laser is preferably a direction perpendicular to the outer joint surface 23 (see arrow L in Fig. 6). Thereby, the inner joint surface 37 and the outer joint surface 23 are laser welded at the joint position 41, and a circumferential joint portion 40 (see Fig. 4) is formed. By joining the inner joint surface 37 and the outer joint surface 23 at the joint portion 40, a resin double container 10 with an airtight intermediate space 28 filled with krypton gas between the outer container 20 and the inner container 30 can be obtained.

[0069] Finally, rotate the mouth holder 61 counterclockwise with respect to the inner container 30 to release the holding of the mouth portion 32, and as shown in Fig. 10(f), lift the mouth holder 61 and the airtight forming jig 65 (upward arrow G in the figure) and lower the outer container holder 71, then the completed resin double container 10 can be taken out from the assembling apparatus 50.

[0070] The above description is for explaining the present invention and should not be construed as limiting or narrowing the invention described in the claims. Also, each component configuration of the present invention is not limited to the above embodiment, and it goes without saying that various modifications are possible within the technical scope described in the claims.

[0071] For example, the shapes, forms, sizes, wall thicknesses, etc. of the outer container 20 and the inner container 30 are not limited to the above embodiment.

[0072] Also, the assembling apparatus 50 and the assembling method of the resin double container 10 described in the embodiments are merely examples and are not intended to limit the present invention.

Explanation of Reference Numerals

[0073] 10 Resin double container 20 Outer container 21 Opening edge 23 Outer joint surface 28 Intermediate space 30 Inner container 32 Mouth part 34 Shoulder part 35 Umbrella part 37 Inner joint surface 38 Bulging part 40 Joint part 41 Joint position

Claims

1. A resin double container having an inner container fitted into a resin outer container having an opening edge on the upper surface, and having a joint portion where the outer container and the inner container are welded and joined along the circumferential direction, wherein the joint portion is provided below the opening edge, the outer container has an outer joint surface on the inner surface side at the joint portion, the inner container has an inner joint surface on the outer surface side at the joint portion, the outer joint surface and the inner joint surface are in a tapered shape inclined downward from top to bottom, at the joint portion, the inner diameter of the outer joint surface is smaller than the outer diameter of the inner joint surface, and the outer joint surface and the inner joint surface are in contact with each other, a resin double container.

2. The outer joint surface has a linear longitudinal section, the inner joint surface has a curved longitudinal section that bulges outward, The resin double container according to Claim 1.

3. The inner surface of the outer container has a longitudinal section above the outer joint surface that extends vertically to the opening edge, the outer surface of the inner container has a vertical longitudinal section in a portion facing the outer container above the inner joint surface, The resin double container according to Claim 2.

4. The inner container has an umbrella portion that covers the upper side of the opening edge of the outer container, The resin double container according to Claim 3.

5. The outer joint surface and the inner joint surface are in a shape that tapers in diameter from top to bottom, The resin double container according to any one of Claims 1 to 4.

6. The outer joint surface and the inner joint surface are in a shape that tapers in diameter from bottom to top, The resin double container according to any one of Claims 1 to 4.

7. The outer container and the inner container have a circular cross section, The resin double container according to any one of Claims 1 to 4.

8. The outer container and the inner container have a polygonal cross section, The resin double container according to any one of Claims 1 to 4.

Images