Synthetic resin container lid and its manufacturing method

Abstract

To provide a novel synthetic resin container lid and a manufacturing method of the same preventing a breakable thin line 16 from being broken in a container lid pre-formation body set process.SOLUTION: When an upper lid 10 is situated at a closed position, a gap 76 is present between a top surface wall 52 and a connection pole 22. The top surface wall 52 and a tip 26 of the connection pole 22 are anchored via a coupling auxiliary tool 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a synthetic resin container closure comprising a preformed container closure body and a fastening aid, and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 listed below discloses a preformed container lid made of synthetic resin which includes a main body and a top lid, the main body having a closing wall and a cylindrical hanging wall depending from the periphery of the closing wall, the closing wall defining a removal area surrounded by a breakable thin-wall line, the top lid having a top wall and a skirt wall depending from the periphery of the top wall, the outer peripheral surface of the skirt wall being connected to the outer peripheral surface of the hanging wall of the main body via hinge means, the top lid being freely rotatable between a closed position which covers the closing wall of the main body and an open position which exposes the closing wall of the main body, the removal area of ​​the closing wall being provided with a connecting post extending upward and the top wall being formed with a hole penetrating in the axial direction, and when the top lid is positioned in the closed position, the tip of the connecting post extends upward through the hole. Patent Document 1 below further discloses a method for manufacturing a container lid, in which after the above-mentioned container lid pre-formed body has been molded (container lid pre-formed body forming process), the top lid is positioned in a closed position (container lid pre-formed body setting process), and then a heated pressing tool is applied to the tip of the connecting post to fix the tip of the connecting post and the top wall (fixing process). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-109017 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the container lid and its manufacturing method disclosed in Patent Document 1 above, the outer surface of the connecting post comes into contact with the inner surface of the top wall that defines the hole during the container lid preform setting process, so when the top lid is rotated from the open position to the closed position, the connecting post is forced downward by the top lid, applying force to the blocking wall, which may unintentionally break the breakable thin-wall line formed in the blocking wall.

[0005] The present invention has been made in consideration of the above-mentioned facts, and its main technical objective is to provide a new synthetic resin container lid and a manufacturing method thereof that prevent the breakable thin-wall line from being broken during the container lid pre-formed body setting process. [Means for solving the problem]

[0006] After much research, the inventors discovered that the above-mentioned main technical problem could be solved by creating a gap between the top wall and the connecting post when the top cover is positioned in the closed position, and fixing the top wall and the tip of the connecting post via a fastening auxiliary device.

[0007] That is, according to the present invention, a container lid capable of solving the above-mentioned main technical problem is a synthetic resin container lid comprising a combination of a container lid preform and a fastening aid, The container lid preform includes a body and a top lid, the body having a closing wall and a cylindrical depending wall depending from a periphery of the closing wall, the closing wall defining a removal area surrounded by a frangible thinned line; the top cover has a top wall and a skirt wall depending from a periphery of the top wall, the outer peripheral surface of the skirt wall being connected to the outer peripheral surface of the depending wall of the main body via hinge means, and the top cover is freely rotatable between a closed position where it covers the closing wall of the main body and an open position where it exposes the closing wall of the main body; The removal area of ​​the blocking wall is provided with a connecting post extending upward. A recess is formed on the tip surface of the connecting post. At the same time 、a hole penetrating the top wall in the axial direction is formed, and when the top cover is positioned at the closed position, a tip of the connecting post passes through the hole and extends upward, and a gap is present between the top wall and the connecting post; The fastening aid is annular and is inserted into the tip of the connecting post and positioned in the hole formed in the top wall when the top cover is positioned at the closed position, and the top wall is fastened to the tip of the connecting post of the main body through the fastening aid. melt The present invention provides a synthetic resin container lid characterized in that the lid is attached to the container.

[0008] Preferably, the lower surface of the closing wall is formed with a settling prevention piece extending downward beyond the breakable thin line from a base end connected to the inside of the removal area toward the outside of the removal area. The connecting post is preferably located on the opposite side of the removal area from the side where the hinge means is provided as viewed in the diametric direction.

[0009] According to the present invention, there is provided a method for manufacturing a container part, which can solve the above-mentioned main technical problem, comprising: the body having a closing wall and a cylindrical depending wall depending from a periphery of the closing wall, the closing wall defining a removal area surrounded by a frangible thinned line; the top cover has a top wall and a skirt wall depending from a periphery of the top wall, the outer peripheral surface of the skirt wall being connected to the outer peripheral surface of the depending wall of the main body via hinge means, and the top cover is freely rotatable between a closed position where it covers the closing wall of the main body and an open position where it exposes the closing wall of the main body; a container lid preformed body forming step in which a connecting post extending upward is provided in the removal area of ​​the closing wall and a hole penetrating in the axial direction is formed in the top wall, and when the top lid is positioned at the closed position, a tip of the connecting post passes through the hole and forms a container lid preformed body extending upward; a container lid preformed body setting step of setting the upper lid of the container lid preformed body to the closed position after the container lid preformed body molding step, Immediately after the container lid preformed body setting step, a gap exists between the top wall and the connecting post, The manufacturing method includes, after the container lid preform setting step, a fastening aid set fixing step of inserting an annular fastening aid into the tip of the connecting post and positioning it in the hole formed in the top wall, and fixing the tip of the connecting post and the fastening aid.

[0010] Preferably, the fastening aid set and fixing step includes a fastening aid setting step of inserting an annular fastening aid into the tip of the connecting pole and positioning it in the hole formed in the top wall, and a fixing step of fixing the tip of the connecting pole and the fastening aid after the fastening aid setting step. In this case, in the fixing step, it is preferable to apply a heated pressing tool to the tip of the connecting pole and the fastening aid to weld the tip of the connecting pole and the top wall via the fastening aid. A recess is formed in the tip surface of the connecting pole of the container lid preform. It is preferable that an annular recess surrounding the outer periphery of the hole is formed in the upper surface of the top wall of the container lid preform. Preferably, the fastening aid has a plate-shaped base and a hanging portion hanging down from the inner periphery of the base. . good Suitably, the pressing tool has an annular ridge formed on its underside. Effect of the Invention

[0011] According to the present invention, when the top lid is positioned in the closed position, a gap exists between the top wall and the connecting column, and the top wall and the tip of the connecting column are fixed via a fastening auxiliary device, so that the top wall does not apply force to the blocking wall via the connecting column during the container lid preformed body setting process, and therefore the breakable thin-wall line is prevented from breaking during the container lid preformed body setting process. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a preferred embodiment of a synthetic resin container lid constructed according to the present invention. [Diagram 2] 2 is a plan view of the preformed synthetic resin container lid shown in FIG. 1 when the top lid is in an open position. [Diagram 3]3 is a bottom view of the container lid preform shown in FIG. 2. [Figure 4] 3 is a cross-sectional view taken along line AA of the container lid preform shown in FIG. 2. [Diagram 5] 5 is a view showing the top cover in FIG. 4 in a closed position. [Figure 6] 2 is an enlarged plan view showing a fastening assistant for the synthetic resin container lid shown in FIG. [Figure 7] 7 is a cross-sectional view of the fastening aid shown in FIG. 6 taken along line AA. [Figure 8] FIG. 7 is a bottom view of the fastening aid of FIG. 6 . [Figure 9] 7 is a diagram showing a process of combining the fastening aid shown in FIG. 6 with the container lid preform shown in FIG. 2. [Figure 10] 2 is a cross-sectional view of the synthetic resin container lid shown in FIG. 1 with the top lid pivoted in the opening direction. [Figure 11] 11 is a cross-sectional view of the state in which the upper cover has been rotated in the closing direction from the state shown in FIG. 10 and resealed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, preferred embodiments of a synthetic resin container lid and a method for manufacturing the same constructed according to the present invention will be described in more detail with reference to the accompanying drawings.

[0014] Fig. 1 shows a preferred embodiment of a synthetic resin container lid constructed according to the present invention, which is a container lid generally designated by the numeral 2. The container lid 2 is formed by combining a container lid preform 4 shown in Figs. 2 to 5 with a fastening aid 6 shown in Figs. 6 to 8.

[0015] 2 to 5, the container lid preform 4 is formed by injection molding from a suitable synthetic resin such as polyethylene or polypropylene, and includes a main body 8 and a top lid 10. The main body 8 has a closing wall 12 and a cylindrical hanging wall 14 hanging down from the periphery of the closing wall 12. The closing wall 12 is circular in plan view, i.e., in Fig. 2. As can be understood by referring to Fig. 4, the closing wall 12 is inclined upward from one side to the other in the diameter direction, i.e., from the left side to the right side in the figure.

[0016] The blocking wall 12 is defined with a removal area 18 surrounded by a breakable thin-wall line 16. As shown in FIG. 2, the removal area 18 is tapered in a plan view from one side to the other in the diameter direction, that is, from the right side to the left side in the figure, passing through the center of the blocking wall 12. As can be clearly understood by referring to FIG. 4, the breakable thin-wall line 16 is composed of a so-called score formed by locally reducing the thickness. A central protruding pillar 20 protruding upward is formed in the central portion of the removal area 18 of the blocking wall 12. The central protruding pillar 20 is a residue of a flow path formed to allow the molten synthetic resin material injected from the molding machine to flow as required when the container cap preform 4 is molded by injection molding. The upper end surface of the central protruding pillar 20 is a so-called gate portion, which is closed. The removal area 18 of the blocking wall 12 is also provided with a connecting pillar 22 protruding upward. The connecting post 22 is located at the end on the left side in Figs. 2 to 5, on the opposite side to the side where the hinge means described later is provided in the diametric direction in the removed region 18. The connecting post 22 extends upward beyond the central protruding post 20 in the vertical direction. With reference to Fig. 2 together with Fig. 4, the connecting post 22 is divided into a main portion 24 having a cross-sectional shape of a so-called home plate shape and a tip portion 26 located above the main portion 24 and having a circular cross-sectional shape, and a substantially horizontal annular shoulder surface 28 facing upward is defined at the boundary between the main portion 24 and the tip portion 26. As shown in Fig. 2, the top portion 24a in the cross-sectional shape of the main portion 24 faces the left side in the figure, and the lower edge of the side surface of the main portion 24, except for the side surface 24b located opposite to the top portion, is connected to the inner peripheral edge of the breakable thin-wall line 16. As can be understood by referring to Fig. 4 together with Fig. 2, a groove 30 extending in the vertical direction is formed in the top portion 24a of the main portion 24. In addition, an annular protrusion 32 is also formed on the inner peripheral surface of the main portion 24. The upper end surface of the tip portion 26, i.e., the tip surface of the connecting post 22, is closed, and a recess 34 having a circular cross section is formed in the center. As shown in Figures 3 and 4, two settling prevention pieces 36 are formed on the lower surface of the blocking wall 12, which extend downward from the base end connected to the inside of the removal area 18 toward the outside of the removal area 18 beyond the breakable thin-wall line 16.

[0017] On the upper surface of the blocking wall 12, a substantially cylindrical pouring guide wall 38 is formed surrounding the outside of the outer peripheral edge of the removal area 18 and extending upward. The upper end of the pouring guide wall 38 is curved outward in the radial direction. As shown in FIG. 4, the upper end position of the pouring guide wall 38 is set lower than the shoulder surface 28 of the connecting column 22 when viewed in the vertical direction. And, as can be understood by referring to FIG. 2 together with FIG. 4, the upper end position of the pouring guide wall 38 is set so that the required angle region located on the right side in FIG. 2 is locally lower than the other angle regions. On the outer peripheral edge of the upper surface of the blocking wall 12, a cylindrical engaged wall 40 is formed, and an annular engaged protrusion 42 is formed on the upper end of the outer peripheral surface of the engaged wall 40. On the lower surface of the outer peripheral edge of the blocking wall 12, a cylindrical seal wall 44 is formed hanging downward, and the outer peripheral surface of the seal wall 44 faces the inner peripheral surface of the hanging wall 14 at a radial interval.

[0018] A locking means 46 is provided on the lower end of the inner circumferential surface of the hanging wall 14. In the illustrated embodiment, the locking means 46 is composed of a plurality of arcuate ridges extending in the circumferential direction at intervals in the circumferential direction. If desired, the locking means 46 can be composed of annular ridges extending continuously in the circumferential direction. An arcuate notch 47 is formed in the upper end of the outer circumferential surface of the hanging wall 14 at a portion diametrically opposite to a hinge means described later. The hanging wall 14 is further provided with a known separation mechanism including a bottomed annular groove 48 with an open upper surface and an axial slit 50, and by carrying out a required operation after the container lid 2 is attached to the mouth and neck of a container described later and used, the container lid 2 can be separated from the mouth and neck and discarded. For details of such a separation mechanism, please refer to, for example, Japanese Patent No. 6326472, which was filed by the applicant of the present application prior to the present application and has already been granted a patent.

[0019] 2 to 5, the top cover 10 has a circular top wall 52 and a cylindrical skirt wall 54 that hangs down from the periphery of the top wall 52, and the lower end of the outer periphery of the skirt wall 54 is connected to the upper end of the outer periphery of the hanging wall 14 of the main body 8 via hinge means 56, so that the top cover 10 can freely rotate between a closed position (as shown in FIG. 5) in which it covers the closing wall 12 of the main body 8 and an open position (as shown in FIG. 4) in which it exposes the closing wall 12 of the main body 8. A circular hole 58 is formed at a required position of the top wall 52, penetrating it in the axial direction. The hole 58 is gradually enlarged in diameter from the lower surface of the top wall 52 toward the upper surface (as shown in FIG. 5), and an annular recess 60 is formed on the upper surface of the top wall 52, surrounding the outer periphery of the hole 58. The hole 58 will be described in more detail later. An inner cylindrical wall 62 and an outer cylindrical wall 64 are formed on the lower surface of the top wall 52, and two annular shallow grooves 66 are formed between the inner cylindrical wall 62 and the outer cylindrical wall 64. A flange 68 protruding radially outward is provided on the lower end of the outer peripheral surface of the skirt wall 54 at a location opposite the hinge means 56 as viewed in the diameter direction, and a finger can be hooked on the flange 68 when turning the top cover 10 to open or close. Furthermore, a thin-walled arc-shaped protruding piece 70 protruding downward is formed on the lower surface of the skirt wall 54 at a location opposite the hinge means 56 as viewed in the diameter direction. An annular locking ridge 72 is provided on the lower end of the inner peripheral surface of the skirt wall 54, and an annular abutting ridge 74 is also provided on the inner peripheral surface of the skirt wall 54, located above the annular locking ridge 72. As can be clearly understood by referring to Fig. 5, when the top cover 10 is located at the closed position, the annular locking ridge 72 of the top cover 10 is locked to the outer circumferential surface or the lower surface of the locked ridge 42 of the main body 8, the annular abutment ridge 74 of the top cover 10 is abutted against the upper end of the locked wall 40 of the main body 8, the protruding piece 70 of the top cover 10 is aligned with the notch 47 of the main body 8, the outer circumferential surface of the inner cylindrical wall 62 of the top cover 10 is in close contact with the inner circumferential surface of the pouring guide wall 38 of the main body 8, and the tip 26 of the connecting post 22 of the main body 8 is inserted into the hole 58 of the top cover 10, so that the tip 26 extends upward through the hole 58. At this time, it is important that a gap 76 exists between the top wall 52 and the connecting post 22.

[0020] Continuing the explanation of the fastening aid 6 with reference to Figures 6 to 8, the fastening aid 6 can be conveniently molded by injection molding or compression molding from a suitable synthetic resin such as polyethylene or polypropylene. The fastening aid 6 is generally annular, and has an annular base 78 and a cylindrical hanging portion 80 that hangs down from the inner peripheral edge of the base 78. A notch 82 is formed continuously in the circumferential direction on the inner peripheral edge of the upper surface of the base 78. An annular protrusion 84 is formed on the outer peripheral edge of the upper surface of the base 78. In the illustrated embodiment, the fastening aid 6 is molded from the same synthetic resin material as the preformed container lid 4, but it is not necessarily required to be molded from the same synthetic resin material as the preformed container lid 4.

[0021] Next, referring to Fig. 9, a process for manufacturing the container lid 2 by combining the above-mentioned container lid preformed body 4 and the fastening aid 6 will be described. First, the container lid preformed body 4 is formed as described above (container lid preformed body forming process), and the top lid 10 is positioned in the closed position (container lid preformed body setting process). Fig. 9(a) shows a partially enlarged cross-sectional view of the hole 58 and the tip 26 of the connecting post 22 immediately after the container lid preformed body setting process. As described above, it is important that a gap 76 exists between the top wall 52 and the connecting post 22.

[0022] After the container lid preformed body setting step, a fastening aid setting and fixing step is performed. In the fastening aid setting and fixing step, first, as shown in Fig. 9(b), a fastening aid 6 formed separately from the container lid preformed body 4 is inserted into the tip 26 of the connecting column 22 and positioned in the hole 58 formed in the top wall 52. When the fastening aid setting step is performed in the illustrated embodiment, the base 78 of the fastening aid 6 is positioned in the annular recess 60 formed in the top wall 52, the lower surface of the base 78 is seated on the upper surface of the top wall 52, and the outer peripheral surface of the hanging part 80 abuts against the inner peripheral surface of the top wall 52 that defines the hole 58, but the inner peripheral surface of the hanging part 80 is slightly separated from the outer peripheral surface of the connecting column 22 (the inner peripheral surface of the hanging part 80 is close to the outer peripheral surface of the connecting column 22). In other words, the fastening aid 6 is loosely fitted into the tip 26 of the connecting post 22. When the fastening aid 6 is loosely fitted into the tip 26 of the connecting post 22, the outer circumferential surface and the inner circumferential surface of the hanging part 80 may be close to or in contact with the inner circumferential surface of the top wall 52 that defines the hole 58 and the outer circumferential surface of the tip 26 of the connecting post 22, respectively.

[0023] In the fastening aid set fixing step, a fixing step is carried out after the fastening aid setting step to fix the tip 26 of the connecting pole 22 and the fastening aid 6. In the fixing step of the illustrated embodiment, as shown in Fig. 9(c), the container lid preform 4 is supported from below by a jig 86, and a heated pressing tool 88 is applied to the tip 26 of the connecting pole 22 and the fastening aid 6 to weld the tip 26 of the connecting pole 22 and the top wall 52 via the fastening aid 6. At this time, due to the fact that a recess 34 is formed in the tip surface of the tip 26 of the connecting post 22 and that a notch 82 is formed continuously in the circumferential direction on the upper surface of the inner peripheral edge of the base 78 of the fastening aid 6, when the pressing tool 88 is applied to the tip surface of the tip 26, a synthetic resin material generated by melting a part of the tip 26 smoothly dissolves toward the radial outside of the tip 26, resulting in good welding between the tip 26 and the fastening aid 6 and in the appearance of the finished top wall 52 after welding. Furthermore, due to the fact that an annular ridge 84 is formed on the upper surface of the outer circumferential edge of the base 78 of the fastening aid 6, when the pressing tool 88 is caused to act on the annular ridge 84, the annular ridge 84 melts and the synthetic resin material produced dissolves toward the radially outer side of the fastening aid 6, so that the outer circumferential edge of the fastening aid 6 is reliably welded to the container cap preformed body 4 in the annular recess 60, the welding between the tip 26 and the fastening aid 6 is good, and the finished appearance of the top wall 52 after welding is good. Furthermore, the lower surface of the pressing tool 88 is substantially horizontal, but a circular ridge 90 is formed on its outer circumferential edge, and the circular ridge 90 surrounds the annular recess 60 from the outside and acts on the upper surface of the top wall 52. At this time, the action of the pressing tool 88 melts the tip 26 and a part of the fastening aid 6 to produce a synthetic resin material, but the presence of the annular ridge 90 prevents the synthetic resin material from eluting radially outward beyond the annular ridge 90, resulting in a good appearance of the finished top wall 52 after welding. The container lid 2 is thus manufactured, and after the above-mentioned fixing process, the jig 86 and pressing tool 88 are removed from the container lid 2 as shown in Figure 9(d).

[0024] If desired, in the fixing step, instead of applying a heated pressing tool 88 to the tip 26 of the connecting column 22 and the fastening aid 6 to weld the tip 26 of the connecting column 22 to the top wall 52 via the fastening aid 6, the tip 26 of the connecting column 22 and the top wall 52 may be bonded with an appropriate adhesive via the fastening aid 6. Also, if the container lid preform 4 is supported from below by the jig 86, the tip 26 of the connecting column 22 and the fastening aid 6 can be fixed to each other by pressing the pressing tool 88 against the tip 26 of the connecting column 22 from above without heating and plastically deforming it. Furthermore, in the fastening aid setting and fixing process, if the container lid preform 4 is supported from below by a jig 86, the fastening aid 6 can be forced downward relative to the connecting column 22 so that the fastening aid 6 is tightly fitted into the tip 26 of the connecting column 22, in other words, the hanging portion 80 of the fastening aid 6 is firmly engaged between the outer peripheral surface of the tip 26 of the connecting column 22 and the inner peripheral surface of the top wall 52 that defines the hole 58, thereby allowing the fastening aid setting process and the fixing process to be carried out simultaneously.

[0025] Therefore, according to the present invention, when the top lid is positioned in the closed position, a gap exists between the top wall and the connecting column, and the top wall and the tip of the connecting column are fixed via a fastening auxiliary device, so that the top wall does not apply force to the blocking wall via the connecting column during the container lid preformed body setting process, and therefore the breakable thin-wall line is prevented from breaking during the container lid preformed body setting process.

[0026] 1 also shows, by a two-dot chain line, a container lid 2 constructed according to the present invention and a neck of a container to which the container lid 2 is applied. The neck of the container 100, which can be formed from a suitable synthetic resin or glass, is cylindrical with an open top, and is formed with a lockable ridge 102 on the upper end of its outer circumferential surface. The outer circumferential surface of the neck of the container 100 is also formed with a support ring 104 located below the lockable ridge 102 (this support ring 104 is used when transporting the container).

[0027] When the container lid 2 is attached to the mouth and neck portion 100 to seal the mouth and neck portion 100 after the contents have been placed in the container, the container lid 2 is fitted over the mouth and neck portion 100 and forced downward, causing the main body 8 to elastically deform and the locking means 46 formed on the inner peripheral surface of the hanging wall 14 to lock under the locked protrusions 102 of the mouth and neck portion 100. When the contents of the container are consumed, a finger is placed on the underside of the flange portion 68 of the top lid 10 and an upward force is applied to the flange portion 68 with the hinge means 56 as the pivot center. In this way, the force is transmitted to the closing wall 12 through the top wall 52 and the connecting column 22, which are welded together with the fastening aid 6 and are integral with each other, and shear stress is generated in the breakable thin-walled line 16 to displace the closing wall 12 together with the top cover 10 upward about the hinge means 56 as a pivot center, and the breakable thin-walled line 16 is gradually broken from one side opposite the hinge means 56 to the other side in the diameter direction. After the breakable thin-walled line 16 is completely broken, the removal area 18 is pivoted in the opening direction together with the top cover 10 through the connecting column 22 as shown in Fig. 10, and thus a discharge opening is formed in the closing wall 12. Thereafter, the contents of the container are discharged through the discharge opening by appropriately tilting the container.

[0028] After the discharge of the contents is completed, the top cover 10 is rotated in the closing direction, i.e., in the direction covering the blocking wall 12, around the hinge means 56 as the center of rotation, to reach the state shown in Fig. 11. The state shown in Fig. 11 is almost the same as the state shown in Fig. 5, i.e., the state in which the top cover 10 of the container cover preform 4 is positioned in the closed position, but differs from the state shown in Fig. 5 in that the lower surface of the settling prevention piece 36 abuts against the upper surface of the blocking wall 12. The abutment of the lower surface of the settling prevention piece 36 against the upper surface of the blocking wall 12 prevents the removal area 18 separated from the blocking wall 12 from settling below the blocking wall 12. This prevents the outer peripheral edge of the removal area 18 from interfering with the inner peripheral edge of the blocking wall 12 when the top cover 10 is rotated in the opening direction again, and the top cover 10 is rotated smoothly in the opening direction. [Explanation of symbols]

[0029] 2: Container lid 4: Container lid front molded body 6: Fastening aid 8: Main unit 10: Upper lid 12:Occluded wall 14: Hanging wall 16: Breakable thin-walled line 18:Removal area 22: Connecting pillar 26: Tip of (connecting pillar) 52: Top wall 54: Skirt wall 56: Hinge means 58: Hole 76: Gap 88: Pressing tool

Claims

1. A synthetic resin container lid is formed by combining a container lid preform and a fastening aid, The container lid preform includes a body and a top lid, the body having a closing wall and a cylindrical depending wall depending from a periphery of the closing wall, the closing wall defining a removal area surrounded by a frangible thinned line; the top cover has a top wall and a skirt wall depending from a periphery of the top wall, the outer peripheral surface of the skirt wall being connected to the outer peripheral surface of the depending wall of the main body via hinge means, and the top cover is freely rotatable between a closed position where it covers the closing wall of the main body and an open position where it exposes the closing wall of the main body; a connecting post extending upward is provided in the removed region of the closing wall, a recess is formed in a tip surface of the connecting post, and a hole penetrating in the axial direction is formed in the top wall, and when the top cover is positioned at the closed position, a tip portion of the connecting post passes through the hole and extends upward, and a gap exists between the top wall and the connecting post; a fastening aid that is annular and that is inserted into the tip of the connecting post and positioned in the hole formed in the top wall when the top lid is positioned in the closed position, and the top wall is welded to the tip of the connecting post of the main body via the fastening aid.

2. A synthetic resin container lid as described in claim 1, wherein a settling prevention piece is formed on the lower surface of the closure wall, the settling prevention piece extending downward from a base end connected to the inside of the removal area toward the outside of the removal area beyond the breakable thin wall line.

3. 3. The synthetic resin container lid according to claim 1, wherein the connecting post is located on a side of the removal area opposite to a side on which the hinge means is provided as viewed in a diametrical direction.

4. The container includes a main body and a top cover. the body having a closing wall and a cylindrical depending wall depending from a periphery of the closing wall, the closing wall defining a removal area surrounded by a frangible thinned line; the top cover has a top wall and a skirt wall depending from a periphery of the top wall, the outer peripheral surface of the skirt wall being connected to the outer peripheral surface of the depending wall of the main body via hinge means, and the top cover is freely rotatable between a closed position where it covers the closing wall of the main body and an open position where it exposes the closing wall of the main body; a container lid preformed body forming step in which a connecting post extending upward is provided in the removal area of ​​the closing wall and a hole penetrating in the axial direction is formed in the top wall, and when the top lid is positioned at the closed position, a tip of the connecting post passes through the hole and forms a container lid preformed body extending upward; a container lid preformed body setting step of setting the upper lid of the container lid preformed body to the closed position after the container lid preformed body molding step, Immediately after the container lid preformed body setting step, a gap exists between the top wall and the connecting post, a fastening aid set fixing step of inserting an annular fastening aid into the tip of the connecting post, positioning it in the hole formed in the top wall, and fixing the tip of the connecting post and the fastening aid, after the container lid preform setting step.

5. The fastening aid set fixing step includes a fastening aid setting step of inserting an annular fastening aid into the tip of the connecting post and positioning the annular fastening aid in the hole formed in the top wall; 5. The manufacturing method according to claim 4, further comprising a fixing step of fixing the fastening aid to the tip end of the connecting post after the fastening aid setting step.

6. 6. The manufacturing method according to claim 5, wherein in the fastening step, a heated pressing tool is applied to the tip of the connecting post and the fastening aid to weld the tip of the connecting post and the top wall via the fastening aid.

7. The method according to claim 6, wherein a recess is formed in the tip surface of the connecting post of the container lid preform.

8. 8. The manufacturing method according to claim 4, wherein an annular recess surrounding an outer periphery of the hole is formed on an upper surface of the top wall of the container lid preform.

9. The manufacturing method according to any one of claims 4 to 8, wherein the fastening assistant tool has a plate-shaped base and a hanging portion hanging down from an inner peripheral edge of the base.

10. 7. The method according to claim 6, wherein the pressing tool has a bottom surface formed with an annular ridge.

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