Synthetic resin cap

Abstract

To provide a synthetic resin cap and a container that can suppress the above-mentioned over-tightening while reducing costs without making any shape changes to the container mouth part having a pouring tube with a male thread formed on the outer peripheral surface.SOLUTION: A synthetic resin cap of the present invention comprises: a cap top surface; an inner ring formed on the cap top surface and capable of sealing against the inner circumferential surface of the pouring spout; a skirt wall extending downward from the cap top surface in a radially outer direction relative to the inner ring; a female thread formed on the inner circumferential surface of the skirt wall to be screwed with the male thread during closure; and a plurality of longitudinal ribs provided at predetermined circumferential intervals along the inner circumferential surface of the skirt wall in a direction above the female thread and extending axially, which guide the movement of a dispensing tube during closure, wherein at least one of the longitudinal ribs located on the end side of the female thread is a stop rib that closely contacts the starting region of the male thread on the discharge cylinder.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a technology for sealing a container mouth, and more particularly to a synthetic resin cap that can be screwed onto a container mouth having a pouring tube, and a container that screws onto the synthetic resin cap. [Background technology]

[0002] Bottle containers such as PET bottles and spouted pouch containers are widely used as containers for storing water, tea, soft drinks, etc. The caps used to seal the mouths of these containers (container mouths) are synthetic resin caps formed into a desired shape by injection molding synthetic resin, for example.

[0003] Such a synthetic resin cap consists of a top plate and a skirt wall that extends axially downward from the periphery of the top plate. An inner ring is formed on the inner surface of the top plate, extending radially inward from the skirt wall and fitting tightly against the inside of the container opening.

[0004] The synthetic resin cap described above is made of a resin that is relatively softer than metal, and therefore, when the cap is screwed onto the container mouth, the inner ring continues to be inserted at an angle relative to the pouring tube, which can cause problems such as inner ring deformation or jamming. In contrast, the synthetic resin cap disclosed in Patent Document 1 has a vertical rib extending axially in the upper part of the inner surface of the skirt. This vertical rib functions as a guide (centering) when the cap is attached to the container mouth, thereby preventing the inner ring from jamming. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-149156 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technologies including those described in the above patent documents still cannot be said to meet market needs, and at least the following problems exist. That is, a synthetic resin cap that is generally screwed onto a container mouth is set to an appropriate tightening range depending on the characteristics of the material, contents, etc. However, it is possible that the cap may be tightened excessively (also referred to as "overtightening") onto the container mouth during the above-described screwing process, exceeding the above-described range, due to, for example, the compatibility of the materials of the container mouth and the cap, climate change, or long-term storage of the packaging material. Such overtightening not only causes discomfort when the cap is re-opened, but can also result in leakage of the contents due to deformation. Therefore, there is a demand for a synthetic resin cap that can suppress the above-described overtightening while keeping costs down.

[0007] One of the objects of the present invention is to provide a synthetic resin cap and a container that can reduce costs and prevent the above-mentioned over-tightening without making any geometric changes to the container mouth, which has a dispensing tube with a male thread formed on its outer surface. [Means for solving the problem]

[0008] In order to solve the above problems, one embodiment of the synthetic resin cap of the present invention is (1) a synthetic resin cap that screws onto a container mouth having a pouring tube with a male thread formed on its outer peripheral surface, and includes a cap top surface, an inner ring formed on the cap top surface and capable of tightly fitting against the inner peripheral surface of the pouring outlet, a skirt wall extending downward from the cap top surface radially outward of the inner ring, a female thread formed on the inner peripheral surface of the skirt wall and that screws into the male thread when the cap is closed, and a plurality of vertical ribs that are provided at predetermined intervals circumferentially on the inner peripheral surface of the skirt wall and extend along the axial direction above the female thread, and that guide the movement of the pouring tube when the cap is closed, and at least one of the vertical ribs located on the terminal side of the female thread is a stopper rib that tightly fits against the starting end region of the male thread of the pouring tube.

[0009] Furthermore, in the synthetic resin cap described in (1) above, (2) it is preferable that the stopper rib extends downward in the axial direction so as to connect with the upper surface of the female thread located at the top of the axial direction.

[0010] Furthermore, in the synthetic resin cap described in (1) or (2) above, (3) it is preferable that the lower ends of the vertical rib and the stopper rib are positioned lower in the axial direction than the lower end of the inner ring.

[0011] In the synthetic resin cap described in (1) or (2) above, (4) it is preferable that the circumferential length of the stopper rib is equal to or greater than the circumferential length of the vertical rib.

[0012] Furthermore, in the synthetic resin cap described in (1) or (2) above, (5) it is preferable that the side of the stopper rib facing the closing direction has an inclination that allows it to come into surface contact with the inclined surface at the starting end region of the male thread when the cap is closed.

[0013] Furthermore, in the synthetic resin cap described in (1) or (2) above, (6) it is preferable that the stopper rib has a circumferential extension portion that can adhere closely to the starting end region of the male thread when the starting end region of the male thread rides up during the capping process, thereby maintaining contact resistance.

[0014] In the synthetic resin cap described in (1) or (2) above, (7) it is preferable that one or more stopper ribs are formed corresponding to the number of threads of the male screw of the pouring cylinder. [Effects of the Invention]

[0015] According to the present invention, at least one of the vertical ribs capable of preventing the inner ring from getting caught is used as a stopper rib, thereby reducing costs and enabling the starting region of the male thread of the container mouth to come into contact with this stopper rib when the cap is screwed on, thereby preventing over-tightening. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view of a cap unit consisting of a synthetic resin cap and a container opening according to a first embodiment, viewed obliquely from above. [Figure 2] 2 is a perspective cross-sectional view of the synthetic resin cap of the cap unit according to the first embodiment, taken along the line AA in FIG. 1. FIG. [Figure 3] 2 is a cross-sectional view schematically showing the AA cross section of the synthetic resin cap shown in FIG. 1. FIG. [Figure 4] 2 is a cross-sectional view showing the BB cross section of the synthetic resin cap shown in FIG. 1 in the cap unit according to the first embodiment. FIG. [Figure 5] 4 is a schematic diagram illustrating the contact state between the stopper rib and the male thread (starting end region) of the container opening when the synthetic resin cap according to the first embodiment is set (screwed) on the container opening. FIG. [Figure 6] FIG. 10 is a perspective view of a cross section of a synthetic resin cap according to a second embodiment, viewed obliquely from above. [Figure 7] 10 is a schematic diagram illustrating the contact state between the stopper rib and the male thread (starting end region) of the container opening when the synthetic resin cap according to the second embodiment is set (screwed) on the container opening. FIG. [Figure 8] FIG. 11 is a perspective view of a cross section of a synthetic resin cap according to a third embodiment, viewed obliquely from above. [Figure 9] 10 is a schematic diagram illustrating the contact state between the stopper rib and the male thread (starting end region) of the container opening when the synthetic resin cap according to the third embodiment is set (screwed) on the container opening. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment for preferably carrying out the present invention will be described. For the sake of convenience, the X, Y, and Z directions are defined as appropriate in the following description, but it goes without saying that this does not restrict the scope of the present invention. Regarding matters other than the features of the present invention detailed below, the present invention may be implemented by appropriately referring to the structures of known synthetic resin caps and container openings (such as spouts), including those described in the patent documents mentioned above.

[0018] =First embodiment= [Cap Unit 300] The cap unit 300 will be described with reference to Fig. 1. As shown in Fig. 1, the cap unit 300 in this embodiment is configured to include at least a synthetic resin cap 100 (described later) and a container opening 200 to which the synthetic resin cap 100 can be screwed to close the container opening.

[0019] <Container opening 200> The container opening 200 is configured to have a pouring tube 210 having an outer peripheral surface 210a on which a male thread 220 is formed. The container opening 200 has a function of pouring out contents from a container that contains liquid or solid contents, such as food, drink, or medicine.

[0020] Such a container opening 200 can be injection molded from a known resin material, for example. Suitable resin materials for the container opening 200 include known synthetic resins such as low-density polyethylene (PE), high-density polyethylene (PE), polypropylene (PP), or a mixed resin of PE and PP. The container opening 200 may contain various known additives, such as lubricants such as metal soaps or waxes, and nonionic, cationic, or anionic antistatic agents.

[0021] The container opening 200 of this embodiment can be, for example, a spout. The spout serving as the container opening 200 can be formed, for example, from the same material as the pouch. As an example, the synthetic resin cap 100 of this embodiment, which will be described later, can be screwed onto the container opening 200, which is formed mainly from the same type of PP as the pouch.

[0022] Therefore, the container of this embodiment comprises a container body (e.g., a pouch or bottle) made of, for example, PP or PET, a container mouth (e.g., a spout or bottle outlet) made of the same type of material as the container body, and a synthetic resin cap of the present invention made of, for example, PP, which is capable of sealing the outlet of the container mouth.

[0023] Although a spout can be exemplified as the container mouth 200 in this embodiment, the container mouth 200 may be in a form other than a spout. That is, another example of the container mouth 200 other than the spout described above is the mouth of a bottle that is integrated with the container body, such as the mouth of a PET bottle.

[0024] 1, the container mouth 200 of this embodiment may be configured to include a pouring tube 210 on which the above-mentioned male thread 220 is formed, a known flange portion 230 extending radially outward from the lower end of the pouring tube 210, and a known fastening portion 240 provided below the flange portion 230 and welded or adhered to a known container body such as a pouch. Note that the container body may be in any known form, such as a paper pack or a resin pouch, as long as the container mouth 200 can be fixed.

[0025] <Synthetic Resin Cap 100> A synthetic resin cap 100 according to a first preferred embodiment of the present invention will be described in detail below with reference to Figures 1 to 4. The synthetic resin cap 100 of this embodiment is configured to be able to be screwed onto a container opening 200 having a dispensing tube 210 with a male thread 220 formed on an outer peripheral surface 210a.

[0026] More specifically, the synthetic resin cap 100 of this embodiment is configured to include a cap top surface 10, an inner ring 20, a skirt wall 30, a female thread 40, a vertical rib 50, and a stopper rib 60A. As exemplified in Figures 1 and 3, the synthetic resin cap 100 may also include a tamper-evident band 70 connected to the lower end of the skirt wall 30 via a known weakened portion. Furthermore, the skirt wall 30 and the tamper-evident band 70 may be connected via, for example, a strip-shaped connecting piece 71.

[0027] The cap top surface 10 is configured to have the function of closing the pouring outlet of the container opening 200 when the container is closed. As shown in Fig. 2, an inner ring 20, which will be described later, is provided on the bottom surface of the cap top surface 10 (the surface facing the pouring outlet of the container opening 200). In addition to the inner ring 20, a known outer ring or the like may be provided on the bottom surface of the cap top surface 10, further outwardly than the inner ring 20.

[0028] 2 and 3, the inner ring 20 is provided so as to descend downward in the axial direction (Z direction) on the bottom surface of the cap top surface 10. The inner ring 20 of this embodiment is formed on the cap top surface 10 and configured to be able to come into close contact with the inner circumferential surface of the pouring outlet in the pouring tube 210 of the container opening 200.

[0029] The skirt wall 30 is configured to extend downward from the cap top surface radially outward of the inner ring 20. More specifically, the skirt wall 30 of this embodiment is configured to descend from the periphery of the cap top surface 10, as shown in Figures 2 and 3. Note that, as shown in Figure 1, the outer peripheral surface of this skirt wall 30 may be formed with a plurality of known knurl structures NL (also called knurls) extending in the axial direction (Z direction) and extending in the circumferential direction (θz direction).

[0030] 2 and 3, the female thread 40 is formed on the inner peripheral surface of the skirt wall 30 and is configured to screw together with the male thread 220 of the container opening 200 when the container is closed. In this embodiment, the female thread 40 is formed as a single-start thread, for example, but the number of start threads may be set arbitrarily, such as a three-start thread.

[0031] As shown in Figures 2 and 3, the vertical rib 50 is provided on the inner peripheral surface of the skirt wall 30 so as to extend along the axial direction. The vertical rib 50 has a function of guiding (centering) the movement of the pouring tube 210 so that the inner ring 20 is correctly inserted inside the pouring tube 210 when the synthetic resin cap 100 is attached to the container opening 200 during stoppering. Therefore, as shown in the figures, the lower end 51 side of the vertical rib 50 is provided with a slope for guiding the container opening 200, in which the inner diameter decreases as it goes upward (towards the cap top surface 10) in order to guide the container opening 200. By providing such a vertical rib 50, it is possible to prevent the inner ring 20 from being stopped up in a state where it is inclined obliquely with respect to the pouring tube 210 and is bitten into the pouring tube 210.

[0032] Furthermore, the vertical ribs 50 of this embodiment are provided on the inner peripheral surface of the skirt wall 30 above the female threads 40 (toward the cap top surface 10) so as to extend along the axial direction. As can be seen from Figures 2 and 3, a plurality of such vertical ribs 50 are provided at predetermined intervals in the circumferential direction on the inner peripheral surface of the skirt wall 30. More specifically, the vertical ribs 50 of this embodiment may be provided on the inner peripheral surface of the skirt wall 30 at equal intervals along the circumferential direction (equally spaced in the circumferential direction).

[0033] 2 and 3, in the synthetic resin cap 100 of this embodiment, at least one of the above-mentioned vertical ribs 50 located before the terminal end side of the female thread 40 is made into a stopper rib 60A that is in close contact with the start end region MSR of the male thread 220 of the dispensing tube 210. In this way, the stopper rib 60A of this embodiment is configured to also serve as the above-mentioned vertical rib 50.

[0034] Here, the "starting end region MSR of the male thread 220" refers to the region in which the stopper rib 60A slides, including the starting end of the male thread 220 where engagement with the starting end of the female thread 40 of the synthetic resin cap 100 begins, as illustrated in Figure 5. As an example, the starting end region MSR can be set to a range of approximately 20% from the starting end of the male thread 220, based on the upper limit of the appropriate tightening range, and rotating in the capping direction. The "appropriate tightening range" can be set by experiments, simulations, etc. depending on various conditions such as the container specifications and contents, but an example is a range of ±30° of the tightening center angle.

[0035] As shown in Fig. 3, the stopper rib 60A preferably extends downward in the axial direction so as to connect at least with the upper surface of the female thread 40 located at the uppermost position in the axial direction. In other words, the lower end 61 side of the stopper rib 60A is not inclined for guiding the container opening portion, as provided by the vertical rib 50, and may extend so as to connect with the female thread 40 up to the crest of the thread, but including at least the upper surface of the female thread 40, without reaching the lower surface, in order to exert the stopper function of this embodiment.

[0036] 3 and the like, the "upper surface of the female thread 40 located at the uppermost position" refers to the surface (also referred to as the flank surface) of the thread on the cap top surface 10 side of the thread in the terminal region of the female thread 40 opposite the starting end where engagement with the male thread 220 begins. In this way, the lower end 61 of the stopper rib 60A of this embodiment may be continuous with the upper surface of the female thread 40. As long as the stopper function of this embodiment is exerted, the lower end 61 of the stopper rib 60A does not necessarily have to extend to the upper surface of the female thread 40 located at the top of the axial direction, and a small gap may be formed between this lower end 61 and the upper surface of the female thread 40.

[0037] 3, the height h3 from the cap top surface 10 to the lower end 61 of the stopper rib 60A is set to be higher than the height h2 from the cap top surface 10 to the lower end 51 of the vertical rib 50. Similarly, the height h2 from the cap top surface 10 to the lower end 51 of the vertical rib 50 and the height h3 from the cap top surface 10 to the lower end 61 of the stopper rib 60A are set to be higher than the height h1 from the cap top surface 10 to the lower end of the inner ring 20. In this way, the lower end 61 of the stopper rib 60A in this embodiment is disposed axially lower than the lower end of the inner ring 20. This allows the stopper rib 60A to also have the function of guiding (centering) the movement of the pouring tube 210 in cooperation with the vertical rib 50. Regarding the positional relationship between the lower end 51 of the vertical rib 50 and the lower end of the inner ring 20 in more detail, it is preferable that the position of the lower end 51 of the vertical rib 50 is set so that it is guided by the outer surface 210a of the dispensing tube 210 before the lower end of the inner ring 20 begins to be inserted inside the dispensing tube 210.

[0038] One or more such stopper ribs 60A may be formed corresponding to the number of threads of the male screw 220 in the dispensing tube 210. Since the male screw 220 of this embodiment is configured as a single-start thread, it is preferable that the number of stopper ribs 60A is "1" corresponding to the number of threads of the male screw 220. Note that, for example, if the male screw 220 is configured as a three-start thread, the number of stopper ribs 60A can be set to "3" to match the number of threads of the male screw 220.

[0039] 4, the height h4 of the stopper rib 60A from the skirt wall 30 (the length of protrusion in the inward circumferential direction) may be the same as the height of the vertical rib 50 from the skirt wall 30, or may be set higher than the height of the vertical rib 50. The height h4 of the stopper rib 60A may be set to any height equal to or higher than the height of the vertical rib 50, as long as it does not interfere with the outer peripheral surface 210a of the container opening 200 (corresponding to the valleys of the male threads 220) in the tightened state.

[0040] 4, the circumferential length Lθ1 of the stopper rib 60A in this embodiment is preferably equal to or greater than the circumferential length Lθ2 of the above-described vertical rib 50. As shown in the figure, the side surface 62 of the stopper rib 60A in the plugging direction (the plugging-side side surface 62c) preferably has a taper (slope) that allows surface contact with the inclined portion in the start region MSR of the male thread 220 during plugging. As an example, the stopper rib 60A in this embodiment may have a top surface 63 having a circumferential length approximately equal to that of the top surface 53 of the vertical rib 50, and may further be longer in the circumferential direction than the vertical rib 50 by the length of the plugging-side side surface 62c.

[0041] In this embodiment, the stopper rib 60A may be set to have a small inclination with respect to the axial direction (a direction parallel to the Z direction) (specifically, the degree of inclination of the top surface 63 with respect to the axial direction). In other words, because the stopper rib 60A functions as a stopper when overtightening may occur, it is preferable that the degree of inclination of the top surface 63 with respect to the axial direction be close to 0° (parallel to the axial direction). This makes it possible for the start region MSR of the male thread 220 to come into stronger contact with the stopper rib 60A, thereby maintaining the appropriate tightening range of the cap, even in cases where overtightening as described above may occur.

[0042] <Action of the stopper rib during over-tightening> Next, with reference to FIG. 5, the behavior of the synthetic resin cap 100 when the above-mentioned over-tightening may occur during capping will be described. As described above, the synthetic resin cap 100 has a preset appropriate tightening range (for example, a tightening central angle of ±30°) depending on the product specifications, etc., but over-tightening can occur due to, for example, changes in climate, long-term storage of the packaging material, or excessive bleeding of additives (especially lubricants) from the container mouth.

[0043] To address this issue, the synthetic resin cap 100 of this embodiment is provided with the above-mentioned stopper rib 60A, and is configured so that the stopper rib 60A begins to come into close contact with the starting region MSR of the male thread 220 just before the upper limit angle of the preset tightening range. The "just before the upper limit angle of the tightening range" can be set appropriately depending on the circumferential length of the stopper rib 60A, the degree of protrusion onto the inner peripheral surface, etc. As an example, if the "central tightening angle ±30°" is the normal tightening range, the above-mentioned "just before the upper limit angle of the tightening range" may be set to a position equivalent to about "central angle +30°," which is not yet the upper limit angle but is slightly beyond the reference angle.

[0044] 5 shows a state in which the synthetic resin cap 100 reaches the "upper limit angle of the tightening range" described above when screwed onto the container opening 200. That is, in this embodiment, when the synthetic resin cap 100 exceeds the upper limit angle of the tightening range and may become overtightened, contact resistance occurs between the stopper rib 60A and the start region MSR of the male thread 220 just before the upper limit angle, preventing overtightening. At this time, as can be seen from FIG. 5, the stopper rib 60A has a closing-side side surface 62c, so that the stopper rib 60A and the start region MSR of the male thread 220 come into surface contact.

[0045] That is, the stopper rib 60A and the start region MSR of the male thread 220 are tapered so that they do not butt head-on when the cap is screwed together, but rather the contact area gradually changes (increases) as the cap is screwed in. This prevents the stopper rib 60A from damaging the male thread 220 and prevents over-tightening, while also minimizing any discomfort felt by the user when the cap is screwed in.

[0046] According to the synthetic resin cap 100 of this embodiment described above, by providing the stopper rib 60A described above, overtightening of the cap can be prevented, thereby achieving a stable tightening operation during closure regardless of the product storage period. Furthermore, according to the synthetic resin cap 100, there is no need to change the shape of the container mouth 200 (spout in this example) to prevent overtightening, and design freedom is ensured for the container mouth 200, while by simply changing a portion of the vertical rib 50, overtightening can be prevented on the cap side by utilizing a thread structure without significantly increasing weight, reducing costs.

[0047] In particular, the synthetic resin cap 100 of this embodiment is particularly useful for a mono-material spout (an example of a container opening 200) made of the same material (such as polypropylene) as the pouch (an example of a container body). That is, when forming a mono-material pouch and spout using, for example, the above-mentioned PP, it is conceivable to add a lubricant or an antistatic agent to the spout side from the viewpoint of moldability and transportability.

[0048] It is conceivable that a spout containing such additives may bleed excessively over time, making it impossible to properly tighten the spout under the same conditions as when it was manufactured. Even in such a case, the synthetic resin cap 100 of this embodiment is provided with the stopper rib 60 that also functions as the vertical rib 50, making it possible to maintain the proper tightening range even for a spout containing such additives regardless of the storage period of the packaging material.

[0049] =Second embodiment= Next, a synthetic resin cap 110 according to a second preferred embodiment of the present invention will be described with reference to Figures 6 and 7. The stopper rib 60A in the first embodiment described above has a capping-side side surface 62c on the side facing the capping direction, which has a slope that follows the slope of the starting region MSR of the male thread 220.

[0050] In contrast, the stopper rib 60B of the synthetic resin cap 110 of this embodiment is characterized in that it does not have a taper as described above, but has a wall surface that stands upright almost perpendicularly from the inner peripheral surface of the skirt wall 30. Therefore, in the following embodiments, components having the same functions as those in the first embodiment will be given the same reference numerals, and their description will be omitted as appropriate (the same applies to the third embodiment).

[0051] 6 and 7, the closing-side side surface 62c of the stopper rib 60B in this embodiment is wall-shaped like the opening-side side surface 62o. The side surface 62 of the stopper rib 60B may have the same profile as the side surface 52 of the vertical rib 50 arranged therearound (i.e., the degree of rise from the inner peripheral surface of the skirt wall 30 is the same as that of the vertical rib 50).

[0052] According to the stopper rib 60B of this embodiment configured in this manner, the edge of the stopper rib 60B (the corner formed by the side surface 62 and the top surface 63) bites into and adheres to the start region MSR of the male thread 220. This type of stopper rib 60B also makes it difficult for the start region MSR of the male thread 220 to climb over the side surface of the stopper rib 60B during overtightening, and the sudden increase in contact resistance when the screw reaches "just before the upper limit angle of the tightening range" can also alert the user to the possibility of overtightening.

[0053] =Third embodiment= Next, a synthetic resin cap 120 according to a preferred third embodiment of the present invention will be described with reference to Figures 8 and 9. The stopper rib 60 in the first and second embodiments described above has a circumferential length that is approximately the same as that of the vertical rib 50 or is longer by the length of the closing-side side surface 62c. In contrast, the top surface 63 of the stopper rib 60C in the synthetic resin cap 120 of this embodiment is characterized by having a circumferential extension portion LP that can maintain contact resistance with the male thread 220.

[0054] 8 and 9, the top surface 63 of the stopper rib 60 of this embodiment has a circumferential extension LP that can maintain contact resistance by coming into close contact with the start region MSR of the male thread 220 when the start region MSR of the male thread 220 rides over it during capping, as compared with the stopper rib 60A of the first embodiment described above. That is, the stopper rib 60C of this embodiment has a shape that expands the range in which contact resistance with the male thread 220 is maintained by relatively increasing the circumferential length that functions as a stopper. Such a circumferential extension LG may be set to a circumferential length that is the upper limit of the above-mentioned appropriate tightening range when the start region MSR of the male thread 220 is located at the end on the capping side.

[0055] In this way, the circumferential extension portion LG may have a circumferential length corresponding to the range from the reference angle to the upper limit of the appropriate tightening range. Furthermore, the height h4 of the stopper rib 60C from the skirt wall 30 (the length of the stopper rib protruding in the inward circumferential direction) may be uniform in the circumferential direction, or may be set so that the height decreases toward the closing side (i.e., the front half (opening side) of the stopper rib 60C is higher in the circumferential direction than the rear half (closing side)).

[0056] According to the stopper rib 60C of this embodiment, even if the start region MSR of the male thread 220 climbs up onto the side surface of the stopper rib 60C during overtightening, the male thread 220 and the circumferential extension LG can continue to be in surface contact with each other. As a result, the contact resistance of the stopper rib 60C with the male thread 220 continues for a relatively long period of time, and ultimately, the tightening is completed within the set appropriate tightening range, thereby preventing the above-mentioned overtightening.

[0057] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0058] For example, in each of the above-described embodiments, the stopper rib 60 suppresses overtightening by utilizing the contact resistance when it comes into contact with the start region MSR of the male thread 220, but the stopper rib 60 may have a recessed structure that can engage with a portion of the male thread 220. By providing such an engagement structure for the stopper rib 60, the start region MSR of the male thread 220 can engage within the recessed portion when it reaches "just before the upper limit angle of the tightening range," thereby stopping movement in the capping direction. [Industrial Applicability]

[0059] The present invention is suitable for realizing a synthetic resin cap and a container that can reduce costs and prevent over-tightening that exceeds the appropriate tightening range. [Explanation of symbols]

[0060] 100~120 Synthetic resin cap 10 Cap top 20 Inner Ring 30 Skirt Wall 40 female thread 50 vertical ribs 60 Stopper Rib 61 Bottom end 62 Side 63 Top surface 70 Tamper Evident (TE) Bands

Claims

1. A synthetic resin cap that is screwed onto a container opening having a pouring tube with a male thread formed on the outer circumferential surface, The top of the cap and an inner ring formed on the top surface of the cap and capable of closely contacting the inner circumferential surface of the spout; a skirt wall extending downward from the top surface of the cap radially outward of the inner ring; a female screw formed on an inner peripheral surface of the skirt wall and adapted to be threadedly engaged with the male screw when the cap is closed; A plurality of vertical ribs are provided at predetermined intervals in the circumferential direction on the inner peripheral surface of the skirt wall so as to extend along the axial direction above the female thread, and guide the movement of the pouring cylinder when the cap is closed, At least one of the longitudinal ribs located on the terminal end side of the female thread is a stopper rib that is in close contact with the starting end region of the male thread of the pouring tube. Synthetic resin cap.

2. 2. The synthetic resin cap according to claim 1, wherein the stopper rib extends downward in the axial direction so as to connect with an upper surface of the female thread located at the uppermost position in the axial direction.

3. 3. The synthetic resin cap according to claim 1, wherein lower ends of the longitudinal rib and the stopper rib are located lower in the axial direction than a lower end of the inner ring.

4. 3. The synthetic resin cap according to claim 1, wherein the circumferential length of said stopper rib is equal to or greater than the circumferential length of said longitudinal rib.

5. 3. The synthetic resin cap according to claim 1, wherein a side surface of the stopper rib facing the closing direction has an inclination that allows surface contact with an inclined surface at a start end region of the male thread when the cap is closed.

6. 3. The synthetic resin cap according to claim 1, wherein the stopper rib has a circumferential extension that can maintain contact resistance by coming into close contact with the starting end region of the male thread when the starting end region of the male thread rides over the stopper rib during the capping process.

7. 3. The synthetic resin cap according to claim 1, wherein one or more stopper ribs are formed corresponding to the number of threads of the male screw of the pouring cylinder.

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