Sealing device

Abstract

To provide a sealing device capable of excellent molding of an inner plug.SOLUTION: A sealing device 100 includes a body 10 and a cap 20, enables attachment and detachment of the cap 20 by a first fastening part 50a provided between the body 10 and the cap 20, and separates an inner plug 12 from the body 10 and captures it by the cap 20 when unsealed by a second fastening part 50b provided between the body 10 and the cap 20 inside the first fastening part 50a. The inner plug 12 has: a sealing part 41 arranged at the bottom of the inner plug 12; an outer peripheral side boundary part 17 connected to the outer edge of the sealing part 41 and the lower end part of an inner plug cylindrical part 42, and connected to the outer peripheral part of the body 10 by an annular thin part 15; and a damming part 17a formed at the boundary between the outer peripheral side boundary part 17 and the sealing part 41 or the inner plug cylindrical part 42 to guide resin flow toward an upper part of the inner plug cylindrical part 42 during molding.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sealing device to be attached to the mouth of a container, and more particularly to a sealing device that improves the molding of an inside plug. [Background technology]

[0002] A known sealing device used for the mouth of a container includes an inner plug and a cap, in which a blocking body or plug that blocks the spout is connected to the inner plug via an easily breakable portion or a thin-walled weakened portion (see Patent Documents 1 and 2).

[0003] Here, when resin is injected from the center of the plug to be molded, in the sealing devices of Patent Documents 1 and 2, there is almost no difference between the flow path width of the cylindrical molding space that forms the part of the inside plug that engages with the cap and the flow path width of the boundary molding space that forms the part connected to the rupture part, and the resin flows into the cylindrical molding space and the boundary molding space at approximately the same time. The resin that flows into the boundary molding space is blocked by the rupture part, which becomes thin, and there is a problem that welds are easily generated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-59531 A [Patent Document 2] JP 2011-173631 A Summary of the Invention

[0005] The present invention has been made in view of the above-mentioned background art, and has an object to provide a sealing device that is capable of favorable molding of an inside plug.

[0006] In order to solve the above problems ofThe sealing device comprises a main body and a cap, and a first fastening portion provided between the main body and the cap enables the cap to be attached and detached, and a second fastening portion provided between the main body and the cap inside the first fastening portion separates the inner plug from the main body and captures it in the cap when opening. The inner plug has a cylindrical inner plug portion fastened to the cap by the second fastening portion, a sealing portion connected to the cylindrical inner plug portion and located at the bottom of the inner plug, an outer periphery boundary portion connected to the outer edge of the sealing portion and the lower end of the cylindrical inner plug portion and connected to the outer periphery of the main body by an annular thin-walled portion, and a dam portion formed at the boundary between the outer periphery boundary portion and the sealing portion or the cylindrical inner plug portion to guide the flow of resin toward the top of the cylindrical inner plug portion during molding. Here, the damming portion is formed by a portion that branches the resin that flows in from the molding space that forms the sealing portion during molding into the molding space that forms the cylindrical portion of the center plug and the molding space that forms the thin-walled portion, and the molding space that forms the damming portion does not dam up the resin being molded in the molding space that forms the cylindrical portion of the center plug, but rather preferentially guides the resin to the molding space that forms the cylindrical portion of the center plug.

[0007] According to the sealing device, the outer peripheral boundary has a damming portion formed to guide the flow of resin toward the upper part of the center plug cylindrical portion during molding, so that the resin can be preferentially filled into the molding space forming the center plug cylindrical portion, which is wider than the molding space forming the thin-walled portion, and the resin can flow into the molding space forming the thin-walled portion after the center plug cylindrical portion is filled to a certain extent with resin. This prevents a large resin pressure from being directly applied to the molding space forming the thin-walled portion from the beginning, and the resin is stably supplied to the molding space and flows continuously without stagnation in the thin-walled portion, making it difficult for welds to occur, and the thin-walled portion and the main body can be molded well. In addition, by preferentially filling the center plug cylindrical portion with resin, sink marks due to insufficient cooling of the center plug cylindrical portion, which is thicker than the thin-walled portion, are less likely to occur, and the thin-walled portion and the main body can be molded well.

[0008] In a specific embodiment or aspect of the present invention, in the sealing device, the minimum thickness of the outer peripheral boundary portion is thinner than the thickness of the sealing portion. In this case, the cooling of the resin can be accelerated in the outer peripheral boundary portion. This allows the molding cycle of the main body to be accelerated while maintaining the sealing and opening properties of the inside plug.

[0009] In another aspect of the present invention, the outer circumferential boundary portion has an annular groove portion formed by transferring a bank portion on the mold side that guides the flow of resin during molding by an annular step provided on the side of the cylindrical plug portion relative to the sealing portion as a damming portion. In this case, the bank portion acts as a breakwater during molding, allowing the resin to be preferentially filled into the molding space that forms the cylindrical plug portion.

[0010] In yet another aspect of the present invention, the imaginary line extending from the inner wall surface of the groove portion is tangent to the outer wall surface of the cylindrical portion of the center plug. In this case, a uniform passage toward the back of the cylindrical portion of the center plug is formed, and the resin that reaches the bank portion during molding can be more easily guided to the molding space that forms the cylindrical portion of the center plug than to the molding space that forms the thin-walled portion.

[0011] In still another aspect of the present invention, the height of the groove is equal to or greater than half the thickness of the sealing portion.

[0012] In yet another aspect of the present invention, the outer circumferential boundary portion has a flow path portion extending downward from the groove portion toward the thin-walled portion. In this case, during molding, the flow of resin into the molding space that forms the cylindrical portion of the center plug is prioritized, and after the molding space that forms the cylindrical portion of the center plug is filled with resin, the flow of resin can be delayed via the flow path portion to facilitate the introduction of resin into the molding space that forms the thin-walled portion.

[0013] In yet another aspect of the present invention, the outer circumferential boundary portion has a flow path portion extending downward toward the thin-walled portion, and the end portion of the flow path portion on the sealing portion side is the damming portion. In this case, the end portion of the flow path portion on the sealing portion side acts as a breakwater during molding, allowing the resin to be preferentially filled into the molding space that forms the center plug cylindrical portion.

[0014] In yet another aspect of the present invention, the flow path portion has a convex portion at the end on the thin-wall portion side that temporarily suppresses the flow of the resin during molding. In this case, the flow of the resin is temporarily suppressed in front of the thin-wall portion during molding to appropriately relieve the resin pressure, and the molding of the thin-wall portion can be made better.

[0015] In yet another aspect of the present invention, adjacent to the second fastening portion, there is a ratchet portion composed of a cap-side cap ratchet and a body-side body ratchet. The first fastening portion is a right-thread type screw portion composed of a cap-side cap external thread and a body-side body external thread, and the second fastening portion is an engaging portion composed of a cap-side cap engaging portion and a body-side body engaging portion.

[0016] In yet another aspect of the present invention, the first fastening portion is a right-thread type screw portion composed of a cap-side cap external thread and a body-side body external thread, and the second fastening portion is a reverse-thread type screw portion composed of a cap-side cap internal thread and a body-side body internal thread.

Brief Description of the Drawings

[0017] [Figure 1] (A) is a conceptual plan view for explaining the main body and the ratchet portion of the sealing device according to the first embodiment of the present invention, and (B) is a cross-sectional view for explaining the sealing device. [Diagram 2] (A) is a partially enlarged cross-sectional view for explaining the main body of the sealing device in FIG. 1(B), and (B) is a conceptual diagram for explaining the flow of the resin during molding. [Diagram 3] (A) and (B) are partially enlarged cross-sectional views for explaining the main body of the sealing device according to the second embodiment of the present invention. [Figure 4] It is a partially cross-sectional view for explaining the sealing device according to the third embodiment of the present invention. [Diagram 5] It is a partially enlarged cross-sectional view for explaining the main body of the sealing device according to the fourth embodiment of the present invention. [Figure 6] It is a partially enlarged cross-sectional view for explaining a modified example of the main body of the sealing device in FIG. 1(B). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [First embodiment] A sealing device according to a first embodiment of the present invention will be described with reference to Fig. 1. The illustrated sealing device 100 is composed of a main body 10 attached to an opening 2a of a container 2, such as a paper pack or a pouch container, and a cap 20 attached to the main body 10 so as to cover the main body 10.

[0019] 1(A) and 1(B), the main body 10 is an integrally molded resin product, and includes an outer periphery 11 fixed along the peripheral edge 2b of the opening 2a of the container 2, and an inner plug 12 that is separated from the outer periphery 11 when the container is opened. Hereinafter, opening refers to the separation of the inner plug 12 from the outer periphery 11, and the opening and closing of the cap 20 after opening will be referred to as opening or closing.

[0020] The outer peripheral portion 11 of the main body 10 is a portion that forms a spout for the contents of the container 2 after the inner plug 12 is separated, and has a main body outer peripheral wall 31 that is a cylindrical member that extends to the outside or upper side of the container 2 along the screw axis AX that is the axis of the main body 10. Furthermore, the outer peripheral portion 11 has a thick main body base 32 that protrudes radially outward at the lower end of the main body outer peripheral wall 31, and a thin welded portion 33 that protrudes radially outward from the peripheral surface of the main body base 32. The upper surface of the welded portion 33 is fixed to the lower surface of the peripheral portion 2b of the container 2 by ultrasonic welding, adhesive bonding, or the like. On the peripheral surface of the main body base 32, locking portions 34 are formed at equal intervals in the circumferential direction at 2 to 8 locations so as to protrude radially outward. In the example of FIG. 1(A), the locking portions 34 are formed at four locations. In addition, a main body outer thread 51 that is a positive thread for screwing into the cap 20 is formed on the outer peripheral surface of the main body outer peripheral wall 31 of the main body 10. The screw axis AX means an axis passing through the center of the main body 10 and the cap 20 or a rotation axis of the cap 20.

[0021] The inside plug 12 of the main body 10 includes a disk-shaped sealing portion 41 disposed at the bottom, a cylindrical inside plug cylindrical portion 42 extending upward from the outer edge of the sealing portion 41, and an outer circumferential boundary portion 17 connected to the outer edge of the sealing portion 41 and the lower end of the inside plug cylindrical portion 42. The outer circumferential boundary portion 17 is connected to the outer circumferential portion 11 of the main body 10 by an annular thin-walled portion 15. An annular V-groove-shaped score 16 is formed on the lower surface of the thin-walled portion 15. The thin-walled portion 15 is cut when the inside plug 12 is separated from the main body 10 and opened. The inside plug cylindrical portion 42 is disposed concentrically and spaced apart inside the outer main body outer circumferential wall 31. A first inside plug engaging portion 52 is formed at the upper end of the inner circumferential surface (inner surface) of the inside plug cylindrical portion 42, which protrudes inward in the center plug radial direction and extends in the circumferential direction. The first inside plug engaging portion 52 engages with a first cap engaging portion 55 provided on the cap 20 described later by moving from below to prevent the inside plug 12 from falling off the cap 20. In addition, on the outer peripheral surface (outer surface) of the inside plug cylindrical portion 42, second inside plug engaging portions 53 (main body ratchet) that protrude outward in the inside plug radial direction and constitute one of the first teeth of the ratchet mechanism are formed at equal intervals in the circumferential direction at a plurality of locations. In the example of FIG. 1(A), the second inside plug engaging portions 53 are formed at four locations. The second inside plug engaging portion 53 has a first engaging surface 53a that is formed by curving sharply from the approximately radial direction and engages with a second tooth portion of the cap 20 described later, and a first non-engaging surface 53b that is formed on the opposite side of the first engaging surface 53a by curving more gently than the first engaging surface 53a.

[0022] The cap 20 is an integrally molded resin product, and includes a disk-shaped cap top plate 21 and a cylindrical cap outer peripheral wall 22 as outer parts. A knurling is formed around the periphery of the cap outer peripheral wall 22. The cap 20 includes a cap cylindrical portion 23, which is an inner support portion arranged on the inner side and concentric with the cap outer peripheral wall 22, and an outer support portion 24 arranged on the outer side of the cap cylindrical portion 23. In addition, an inner ring 25, which is also concentric and cylindrical but relatively short in the direction of the screw axis AX, is provided between the cap outer peripheral wall 22 and the outer support portion 24. This inner ring 25 seals the opening 2a of the container 2 after opening. The cap cylindrical portion 23, the outer support portion 24, and the inner ring 25 are connected by the cap top plate 21. A cap outer thread 54 is formed on the inner peripheral side of the cap outer peripheral wall 22, which is screwed into the main body outer thread 51 formed on the outer peripheral side of the main body outer peripheral wall 31 of the main body 10. At the lower end of the outer peripheral surface (outer side surface) of the cap cylindrical portion 23, a first cap engagement portion 55 is formed, which protrudes outward in the cap radial direction and extends in the circumferential direction. The first cap engagement portion 55 engages with the first inside plug engagement portion 52 provided on the inside plug 12 by moving from above. In addition, the outer support portion 24 constitutes the other second tooth portion of the ratchet mechanism, and second cap engagement portions 56 (cap ratchets) that engage with the second inside plug engagement portion 53 formed on the outer peripheral side surface of the inside plug cylindrical portion 42 of the inside plug 12 provided on the main body 10 are formed at equal intervals at multiple locations in the circumferential direction. The second cap engagement portion 56 is paired with the second inside plug engagement portion 53, and in the example of FIG. 1(A), the second cap engagement portion 56 is formed at four locations, the same number as the second inside plug engagement portions 53. The second cap engagement portion 56 has a second engagement surface 56a that is formed at an incline relative to the circumferential direction and engages with the second center plug engagement portion 53, which is the first tooth portion of the center plug 12, and a second non-engagement surface 56b that is formed on the opposite side of the second engagement surface 56a and is inclined in the same direction as the second engagement surface 56a so that the second cap engagement portion 56 is tapered in a planar view.

[0023] In the above, the body external thread 51 of the body outer peripheral wall 31 of the body 10 and the cap external thread 54 of the cap outer peripheral wall 22 of the cap 20 constitute a first fastening portion 50a that enables the cap 20 to be attached to and detached from the body 10. The first fastening portion 50a is, for example, a positive-thread type screw-type engagement portion that loosens when rotated counterclockwise. In addition, the first inside plug engaging portion 52 of the inside plug cylindrical portion 42 of the body 10 and the first cap engaging portion 55 of the cap cylindrical portion 23 of the cap 20 constitute a second fastening portion 50b for engaging and fixing the inside plug 12 of the body 10 to the cap cylindrical portion 23 of the cap 20. The cap cylindrical portion 23 of the cap 20 functions as a support portion for capturing the inside plug 12 by the second fastening portion 50b, which is an engaging portion, and separating the inside plug 12 from the body 10 or the outer peripheral portion 11.

[0024] As described above, the second inside plug engaging portion 53 of the inside plug cylindrical portion 42 of the main body 10 and the second cap engaging portion 56 of the outer support portion 24 of the cap 20 constitute a ratchet portion 50c that engages with each other in one direction. Specifically, when the cap 20 is rotated in a direction in which the cap 20 is loosened from the opening 2a of the container 2, i.e., in a counterclockwise direction as viewed from above the cap 20, the first engaging surface 53a of the second inside plug engaging portion 53 and the second engaging surface 56a of the second cap engaging portion 56 engage with each other. On the other hand, when the cap 20 is rotated in a direction in which the cap 20 is tightened from the opening 2a of the container 2, i.e., in a clockwise direction as viewed from above the cap 20, the second non-engaging surface 56b of the second cap engaging portion 56 slides over the first non-engaging surface 53b of the second inside plug engaging portion 53 while being elastically deformed, and passes over the second inside plug engaging portion 53. When the sealing device 100 is not yet opened, rotating the cap 20 in the direction to loosen it causes the second inner plug engagement portion 53 and the second cap engagement portion 56 to engage with each other, and a force is generated in the rotational direction that separates the thin-walled portion 15 of the inner plug 12 from the outer circumferential portion 11 of the main body 10, resulting in the breakage of the thin-walled portion 15.

[0025] Hereinafter, the periphery of the outer circumferential boundary 17 of the inside plug 12 will be mainly described with reference to Figs. 2(A) and 2(B). The minimum thickness T1 of the outer circumferential boundary 17 is thinner than the thickness T2 of the sealing portion 41. Here, the thickness of the outer circumferential boundary 17 corresponds to the flow path width of the molding space forming the outer circumferential boundary 17, and the thickness of the sealing portion 41 corresponds to the flow path width of the molding space forming the sealing portion 41. By making the outer circumferential boundary 17 thinner than the sealing portion 41, the cooling of the resin can be made relatively fast at the outer circumferential boundary 17. As a result, the molding cycle of the main body 10 can be made faster while maintaining the sealing and unsealing properties of the inside plug 12. In addition, the inside plug 12 has a damming portion 17a formed at the boundary between the outer circumferential boundary 17 and the sealing portion 41 or the inside plug cylindrical portion 42 to guide the flow of the resin to the upper part of the inside plug cylindrical portion 42 during molding. Here, the damming portion 17a is formed by a portion that branches the resin flowing from the molding space that forms the sealing portion 41 during molding into the molding space that forms the center plug cylindrical portion 42 and the molding space that forms the thin-walled portion 15, and the molding space that forms the damming portion 17a does not dam the resin being molded to the molding space that forms the center plug cylindrical portion 42, but preferentially guides the resin to the molding space that forms the center plug cylindrical portion 42. In this embodiment, the outer peripheral boundary portion 17 has, as the damming portion 17a, an annular groove portion 18 formed by transferring a bank portion 60 on the mold side that guides the flow of resin by an annular step 17b provided on the center plug cylindrical portion 42 side with respect to the sealing portion 41. As shown in FIG. 2(A), the groove portion 18 has a shape that is an inversion of the bank portion 60 on the mold side indicated by the dashed line. The bank portion 60 or the groove portion 18 is located on the end side of the molding space that forms the sealing portion 41 during molding. The bank portion 60 or the groove portion 18 acts as a breakwater to prevent the resin, which has flowed in from the lower center of the molding space forming the sealing portion 41, from flowing into the outer circumferential boundary portion 17 when it reaches the bank portion 60 or the groove portion 18. The bank portion 60 or the groove portion 18 makes it easier for the resin to flow preferentially into the molding space forming the center plug cylindrical portion 42 located above the bank portion 60 or the groove portion 18, and the flow of the resin can be intentionally controlled. The height of the groove portion 18 is, for example, ½ or more of the thickness of the sealing portion 41.

[0026] 2(A), an imaginary line L1 extending from the inner wall surface 18a of the groove portion 18 contacts the outer wall surface 42a of the center plug cylindrical portion 42. This forms a uniform passage toward the back of the center plug cylindrical portion 42, making it easier to guide the resin that reaches the bank portion 60 or the groove portion 18 during molding to the molding space that forms the center plug cylindrical portion 42 rather than the molding space that forms the thin-walled portion 15.

[0027] In addition, the outer circumferential boundary portion 17 has a flow path portion 19 extending downward from the groove portion 18 toward the thin wall portion 15. This allows the resin to be preferentially introduced into the molding space that forms the inner plug cylindrical portion 42 during molding, and after the molding space that forms the inner plug cylindrical portion 42 is filled with resin, the resin can be easily introduced into the molding space that forms the thin wall portion 15 while delaying the filling of the resin through the flow path portion 19 and preventing excessive pressure from being applied. The flow path portion 19 has a convex portion 19a that temporarily suppresses the flow of resin during molding at the end portion on the thin wall portion 15 side. This allows the resin to temporarily suppress the flow of resin in front of the thin wall portion 15 during molding, causing the resin to stagnate, and the resin pressure can be appropriately alleviated by delaying the flow of resin, thereby improving the molding of the thin wall portion 15.

[0028] As shown in FIG. 2B, the resin flowing in from the lower center of the molding space forming the sealing portion 41 (arrow A1 in FIG. 2B) reaches the bank portion 60 or the groove portion 18 of the outer peripheral boundary portion 17 (arrow A2 in FIG. 2B), and is guided by the blocking portion 17a toward the molding space forming the upper center plug cylindrical portion 42. Thereafter, the resin flows preferentially into the molding space forming the center plug cylindrical portion 42 (arrow A3 in FIG. 2B), and the molding space is filled with the resin. After the molding space forming the center plug cylindrical portion 42 is filled with the resin, the resin flows into the flow path portion 19 of the outer peripheral boundary portion 17 (arrow A4 in FIG. 2B), and fills the molding space forming the thin-walled portion 15, and thus the molding space forming the outer peripheral portion 11 of the main body 10. 2(B), when a convex portion 19a is provided at the end of the flow path portion 19 on the thin-walled portion 15 side, the flow of the resin is temporarily suppressed and the resin pressure is relaxed before the resin flows into the molding space that forms the thin-walled portion 15. Note that when the resin flows preferentially into the molding space that forms the inner plug cylindrical portion 42, a part of the resin whose resin pressure has been relaxed may flow into the molding space that forms the thin-walled portion 15.

[0029] An example of a method for assembling the sealing device 100 will be described below. First, the main body 10 and the cap 20 shown in FIG. 1(B) are prepared. Next, while rotating the main body outer screw 51 and the cap outer screw 54 constituting the first fastening portion 50a clockwise, the first cap engagement portion 55 of the cap 20 constituting the second fastening portion 50b and the first inner plug engagement portion 52 of the main body 10 are engaged so as to house the main body 10 in the cap 20. At this time, in the ratchet portion 50c, the second cap engagement portion 56 of the cap 20 and the second inner plug engagement portion 53 of the main body 10 are not engaged with each other, so that the thin-walled portion 15 is not affected.

[0030] The sealing device 100 (main body 10 and cap 20) assembled as described above is inserted from the back side into the opening 2a of a container 2 such as a paper pack, and the outer peripheral surface of the main body base 32 of the main body 10 is fitted into the inner peripheral surface of the opening 2a, and is joined to the container 2 by ultrasonic bonding, adhesive bonding, or the like.

[0031] The unsealing operation of the sealing device 100 of the above embodiment will be described below. First, the cap 20 is in a reference position or initial position (screwed all the way in) before the rotation of the first fastening portion 50a, the inside plug 12 and the main body outer peripheral wall 31 are in a coupled state, and the opening 2a of the container 2 or the opening 11a of the main body 10 is in a sealed state. When the cap 20 is rotated in a loosening direction, i.e., counterclockwise, the second cap engaging portion 56 and the second inside plug engaging portion 53 engage with each other in the ratchet portion 50c, a rotating force acts on the inside plug 12 and a twisting force is applied to the thin-walled portion 15, which is broken by the shear force, and the inside plug 12 is separated from the main body outer peripheral wall 31 and unsealed. In this state, the locked state by the second fastening portion 50b is maintained, and the inside plug 12 is held by the cap 20.

[0032] Furthermore, when the cap 20 is rotated in the direction to loosen it, the cap 20 separates from the outer circumferential wall 31 of the main body, thereby making it possible to pour the contents in the container 2. At that time, the inside plug 12 is secured to the cap 20, so there is no risk of it coming off. In other words, once the container is opened, the inside plug 12, which was fixed to the main body 10, is now fixed to the cap 20.

[0033] After opening, the cap external threads 54 of the cap 20 are screwed into the body external threads 51 of the body 10, and the cap 20 is rotated clockwise, so that the lip portion 31a formed on the upper end of the body outer peripheral wall 31 abuts against the lower surface 21t of the cap top plate 21 of the cap 20. The inside plug 12 is held in the cap 20 by the second fastening portion 50b.

[0034] In the sealing device 100 of this embodiment, the outer peripheral boundary portion 17 has a blocking portion 17a formed to guide the flow of resin toward the upper portion of the center plug cylindrical portion 42 during molding, so that the resin is preferentially filled into the molding space forming the center plug cylindrical portion 42, which is wider than the molding space forming the thin-walled portion 15, and the resin can flow into the molding space forming the thin-walled portion 15 after the center plug cylindrical portion 42 is filled to a certain extent with resin. This prevents a large resin pressure from being directly applied to the molding space forming the thin-walled portion 15 from the beginning, and the resin is stably supplied to the molding space and flows continuously without stagnating in the thin-walled portion 15, making it difficult for welds to occur, and the thin-walled portion 15 and the main body 10 can be molded well. In addition, by preferentially filling the center plug cylindrical portion 42 with resin, sink marks due to insufficient cooling of the center plug cylindrical portion 42, which is thicker than the thin-walled portion 15, are less likely to occur, and the thin-walled portion 15 and the main body 10 can be molded well.

[0035] Second Embodiment Hereinafter, a sealing device according to the second embodiment will be described. The sealing device according to the second embodiment is a modified version of the sealing device according to the first embodiment, and matters that are not specifically described are similar to those of the sealing device according to the first embodiment.

[0036] 3(A) and 3(B), in this embodiment, an imaginary line L1 extending from the inner wall surface 18a of the groove portion 18 of the outer circumferential boundary portion 17 is in contact with the outer wall surface 42a of the center plug cylindrical portion 42 and is inclined with respect to the screw axis AX. In a cross-sectional view, the groove portion 18 may be, for example, V-shaped as shown in Fig. 3(A), or may be trapezoidal or U-shaped as shown in Fig. 3(B).

[0037] In the first embodiment, the flow path portion 19 of the outer circumferential boundary portion 17 extends downwardly approximately parallel to the screw axis AX, but it may extend downwardly at an angle to the screw axis AX, as shown in Figures 3(A) and 3(B).

[0038] Third Embodiment Hereinafter, a sealing device according to a third embodiment will be described. The sealing device according to the third embodiment is a modification of the sealing device according to the first embodiment, and matters that are not specifically described are similar to those of the sealing device according to the first embodiment.

[0039] As shown in FIG. 4, in this embodiment, the first fastening portion 50a is a positive-thread type threaded portion composed of a cap outer thread 54 on the cap 20 side and a body outer thread 51 on the body 10 side, and the second fastening portion 50b is a reverse-thread type threaded portion composed of a cap inner thread 58 on the cap 20 side and a body inner thread 57 on the body 10 side. The body inner thread 57 is formed on the inner circumferential surface (inner surface) of the inside plug cylindrical portion 42, and has a different helical direction from the body outer thread 51. The cap inner thread 58 is formed on the outer circumferential surface (outer surface) of the cap cylindrical portion 23 so as to screw into the body inner thread 57. The body inner thread 57 and the cap inner thread 58 have a biased thread shape or a burr shape that makes it easier to push the inside plug 12 into the cap cylindrical portion 23 than to pull the inside plug 12 out of the cap cylindrical portion 23.

[0040] In this embodiment, as in the first embodiment, the center plug 12 has a damming portion 17a formed at the boundary between the outer peripheral boundary portion 17 and the sealing portion 41 or the center plug cylindrical portion 42 in order to guide the flow of resin toward the upper portion of the center plug cylindrical portion 42 during molding.

[0041] In assembling the sealing device 100, the body outer thread 51 and the cap outer thread 54 constituting the first fastening portion 50a are rotated clockwise while the cap inner thread 58 of the cap 20 and the body inner thread 57 of the body 10 constituting the second fastening portion 50b are screwed together so as to house the body 10 in the cap 20. At this time, the body inner thread 57 and the cap inner thread 58 constituting the second fastening portion 50b are originally formed to be screwed together by rotating in the counterclockwise direction, but since both inner threads 57, 58 shown in the figure are formed with a biased thread shape or a burr shape that is easily deformed when pressed in, the threads of both inner threads 57, 58 are deformed relative to each other and overcome the threads of each other to mesh with each other.

[0042] Regarding the unsealing operation of the sealing device 100 of the above embodiment, when the cap 20 is rotated in a direction to loosen, i.e., counterclockwise, the cap outer thread 54 comes into contact with the body outer thread 51. At this time, since the inside plug 12 is screwed with the cap 20 by the reverse thread, the second fastening portion 50b starts to be tightened, the inside plug 12 is moved upward, and the thin-walled portion 15 is stretched upward accordingly. When the cap 20 is further rotated counterclockwise, the cap 20 moves upward while rotating due to the screwing of the cap outer thread 54 and the body outer thread 51, during which the thin-walled portion 15 of the body 10 is subjected to further shear force and is broken, and the inside plug 12 is detached from the body outer peripheral wall 31 and opened.

[0043] [Fourth embodiment] Hereinafter, a sealing device according to a fourth embodiment will be described. The sealing device according to the fourth embodiment is a modification of the sealing device according to the first embodiment, and matters that are not specifically described are similar to those of the sealing device according to the first embodiment.

[0044] In this embodiment, unlike the first embodiment, the outer circumferential boundary 17 does not have a groove 18. As shown in FIG. 5, the minimum thickness T1 of the outer circumferential boundary 17 is thinner than the thickness T2 of the sealing portion 41. Furthermore, the minimum thickness T1 of the outer circumferential boundary 17 is thinner than the thickness T3 of the inner plug cylindrical portion 42. As a result, the resin flows preferentially to the thicker side, so that the resin easily flows toward the inner plug cylindrical portion 42. In addition, the inner plug 12 has a damming portion 17a formed at the boundary between the outer circumferential boundary 17 and the sealing portion 41 or the inner plug cylindrical portion 42 to guide the flow of the resin toward the upper part of the inner plug cylindrical portion 42 during molding. In this embodiment, the outer circumferential boundary 17 has a flow path portion 119 extending downward toward the thin wall portion 15, and the end of the flow path portion 119 on the sealing portion 41 side is the damming portion 17a. As a result, the end of flow path portion 119 on the sealing portion 41 side acts as a breakwater during molding, allowing resin to be preferentially filled into the molding space that forms inner plug cylindrical portion 42. Flow path portion 119 has protrusion 19a at the end on the thin-walled portion 15 side that temporarily suppresses the flow of resin during molding.

[0045] Although the sealing device according to the present embodiment has been described above, the sealing device according to the present invention is not limited to the above. For example, in the above embodiment, as shown in Fig. 6, the outer periphery boundary portion 17 may have a structure in which the outer periphery boundary portion 17 does not have the flow path portion 19 extending downward from the groove portion 18 toward the thin-walled portion 15, but has a flow path portion 219 extending approximately parallel to the sealing portion 41. In this case, it is essential to provide the groove portion 18 in the outer periphery boundary portion 17 in order to provide the damming portion 17a.

[0046] In the above embodiment, the inside and outside of the inner plug cylindrical portion 42 of the main body 10 and the cap cylindrical portion 23 of the cap 20 can be interchanged. In this case, the structures of the second fastening portion 50b and the ratchet portion 50c are also appropriately changed.

[0047] In the above embodiment, the specifications such as pitch, number of turns, thread height, shape, etc. of the main body external thread 51 and the cap external thread 54 constituting the first fastening portion 50a can be changed according to the application. The specifications such as pitch, number of turns, thread height, shape, etc. of the cap internal thread 58 and the main body internal thread 57 constituting the second fastening portion 50b can also be changed according to the application.

[0048] In the above embodiment, the shapes of the body external thread 51 and the cap external thread 54 constituting the first fastening portion 50a are not limited to those exemplified in FIG. 1(B) etc., and may be threads having a biased thread shape or a burr shape that makes it easier to push in.

[0049] In the above embodiment, the shapes of the main body internal thread 57 and the cap internal thread 58 constituting the second fastening portion 50b are not limited to those exemplified in Fig. 4, but may have various cross-sectional shapes. Furthermore, the internal threads 57, 58 constituting the second fastening portion 50b are not limited to those formed in a continuous spiral shape, but may be made up of a plurality of separate parts.

[0050] In the above embodiment, the upper surface of the welded portion 33 of the main body 10 is fixed to the lower surface of the peripheral portion 2b of the container 2, but the lower surface of the welded portion 33 may be fixed to the upper surface of the peripheral portion 2b. In this case, the main body base 32 and the welded portion 33 of the main body 10 may have the same thickness, and the locking portion 34 may be omitted. [Explanation of symbols]

[0051] 2...container, 2a...opening, 2b...periphery, 10...main body, 11...outer periphery, 11a...opening, 12...inner plug, 15...thin wall, 16...score, 17...outer periphery boundary, 17a...damming portion, 18...groove portion, 18a...inner wall surface, 19,119,219...flow path portion, 19a...projection portion, 20...cap, 21...cap top plate, 22...cap outer periphery wall, 23...cap cylindrical portion, 24...outer support portion, 25...inner ring, 31...main body outer periphery wall, 31a...lip portion, 32...main body base, 33...welded portion, 34...engagement portion, 41...sealing portion, 42...inner plug cylindrical portion, 42a...outer wall surface, 50a...first fastening portion, 50b...second fastening portion, 50c...ratchet portion, 51...main body external thread, 52...first plug engagement portion, 53...second plug engagement portion, 53a...first engagement surface, 53b...first non-engagement surface, 54...cap external thread, 55...first cap engagement portion, 56...second cap engagement portion, 56a...second engagement surface, 56b...second non-engagement surface, 57...main body internal thread, 58...cap internal thread, 100...sealing device, AX...screw axis, L1...phantom line

Claims

1. A sealing device comprising a body and a cap, a first fastening part provided between the body and the cap that enables the cap to be attached and detached, and a second fastening part provided between the body and the cap on the inner side of the first fastening part that separates an inside plug from the body and captures it in the cap when opening the container, the center plug has a center plug cylindrical portion fastened to the cap by the second fastening portion, a sealing portion connected to the center plug cylindrical portion and disposed at the bottom of the center plug, an outer peripheral boundary portion connected to an outer edge of the sealing portion and a lower end of the center plug cylindrical portion and connected to an outer periphery of the body by an annular thin-walled portion, and a dam portion formed at a boundary between the outer peripheral boundary portion and the sealing portion or the center plug cylindrical portion for guiding a flow of resin toward an upper portion of the center plug cylindrical portion during molding; the blocking portion has a downwardly facing annular groove provided on the inner plug cylindrical portion side with respect to the sealing portion, A sealing device, wherein an upper end of the annular groove has a height equal to or higher than an upper surface of the sealing portion.

2. The sealing device according to claim 1 , wherein a minimum thickness of the outer circumferential boundary portion is less than a thickness of the sealing portion.

3. The sealing device according to claim 1 or 2, wherein an imaginary line extending from an inner wall surface of the groove portion is tangent to an outer wall surface of the inner plug cylindrical portion.

4. 4. The sealing device according to claim 1, wherein the height of the groove is equal to or greater than half the thickness of the sealing portion.

5. The sealing device according to any one of claims 1 to 4, wherein the outer circumferential boundary portion has a flow path portion extending downward from the groove portion toward the thin portion.

6. The sealing device according to claim 5 , wherein the flow path portion has a protrusion at an end portion on the thin-walled portion side for temporarily suppressing a flow of resin during molding.

7. a ratchet portion adjacent to the second fastening portion and including a cap ratchet on the cap side and a body ratchet on the body side; the first fastening portion is a positive-thread type threaded portion configured with a cap external thread on the cap side and a body external thread on the body side, The sealing device according to any one of claims 1 to 6, wherein the second fastening portion is an engagement portion constituted by a cap engagement portion on the cap side and a main body engagement portion on the main body side.

8. the first fastening portion is a positive-thread type threaded portion configured with a cap external thread on the cap side and a body external thread on the body side, The sealing device according to any one of claims 1 to 6, wherein the second fastening portion is a reverse-thread type screw portion constituted by a cap internal thread on the cap side and a body internal thread on the body side.

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