Pilfer-proof cap made of synthetic resin

Abstract: A pilfer-proof cap made of synthetic resins capable of preventing at least a rotation of a packing (9) together with a cap (6) in a simple construction when said cap (6) is removed and holding a sealed-up tightness of a container until a bridge (7) is broken is provided. A cap (6), in which a top wall (1) and a skirt (2) depending from said top wall (1) are comprised and a threaded portion (5) of cap (6) screwed in a threaded portion (4) of container is provided, a plurality of bridges (7), and a packing (9) provided so as to seal up tightly a mouth portion (3) of container during the time when said cap (6) is closed, a packing guide (10), a circular inner sealing member (11) tightly insertable into an inner surface of said mouth portion (3) of container provided in said packing (9) and an air reservoir (12) formed in an upper surface of the packing (9) are comprised.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a pilfer-proof cap made of synthetic resins to be put on a mouth portion of containers such as bottles for use in drinks. Description of the Prior Art A pilfer-proof cap having a container-sealing packing (hereinafter referred to as a packing), in which said packing is held at an appointed position on an inside surface of a top wall of a cap to be simultaneously lifted up together with said cap, whereby releasing a sealing for said container by the packing, when said cap is removed from said container, has been proposed (refer to Japanese Patent Publication No. Sho 62-18421). However, with such the construction, there has been the possibility that the packing is lifted up together with the cap or not removed from but rotated together with the cap to release said sealing for the container, whereby breaking an airtightness, while a bridge holding a band for mechanically engaging the cap with said mouth portion of the container is not broken, when a cap-opening action out of mischief and the like, so-called a slight rotation, is conducted while the cap is not fully removed. And, the cap of this type is not preferably used in view of a protection for contents in the container in the case where a pressure within a sealed-up tightly container filled with contents is higher than that outside of said container (1), the case where said pressure within the sealed-up tightly container becomes equal to a pressure outside of the container and a packing is continuously adhered closely to a mouth portion of container (2), or the case where it is used for sealing up tightly the container filled with a liquid heat treated at a high-temperature or the container which is subjected to a high-temperature heat treatment after filled with a liquid followed by being cooled to room temperature and as a result an inner pressure of the sealed-up tightly container is reduced and a packing is continuously adhered closely to a mouth portion of container by a vacuum generated within the container (3). For example, in case of the above described (1), a gas is leaked, and in cases of the above described (2), (3), the open air is apt to enter the container together with bacteria and consequently the contents of the container are apt to be denatured and corrupted in all of the above described cases (1), (2) and (3). A multi-use screw-on bottle cap known from EP 0 261 047 A1 comprises a screw-on cap and a packing for sealing up tightly a mouth portion of a bottle neck. When the cap is screwed on a bottle neck a conical sealing and adjusting surface of the packing is held in sealing contact with the mouth portion by means of a central projection provided on the lower surface of the top wall of the cap. In addition, a pilfer-proof closure device as described in the preamble of claim 1 is known from EP 0 269 920 A1. SUMMARY OF THE INTENTION The object of the present invention is to provide a pilfer-proof closure device capable of preventing at least a rotation of a packing together with a cap when the cap is removed so as to hold a sealed up tightness of a container until the cap is separated from a pilfer-proof band. This object is achieved by the pilfer-proof closure device according to claim 1. According to the present invention, said packing guide comprising a circular projection provided in said inner circumferential surface of the skirt can be used. That is to say, said circular projection functions so as to mount the cap on the mouth portion of container under the condition that the packing is held on the lower surface side of the top wall of cap when the cap is screwed on to the container. Thus, the mouth portion of container can be sealed up tightly by means of the packing held by the circular projection between the lower surface of the top wall and the circular projection by rotating the cap in the cap-closing direction and moving the threaded portion of cap along the threaded portion of container. In addition, this circular projection functions so as to hold the airtightness of the mouth portion of container by means of the packing at least until the bridges are broken even though the threaded portion of cap moves along the threaded portion of container when the cap is loosened and lift up the packing above the mouth portion of container when the bridges are broken. As shown in for example Figs. 1, 4, the circular projection may be provided integrally with the cap at a position far from the lower surface of the top wall 1 by an appointed distance D between the threaded portion 5 of cap and the top wall 1 or may be formed separately from the cap at the same position. That is to say, this circular projection as the packing guide can hold the airtightness of the container by means of the packing until the bridges are broken and lift up the packing to break the seal when the bridges are broken. Moreover, in view of said appointed distance D, it is possible also that the most upper portion of the conventional threaded portion of cap is used in place of the circular projection. And, this packing (hereinafter referr to merely as packing) is used in the following cases: 1 ○ the case where inner pressure of the seal-up container is reduced when the container is filled with a liquid heat treated at the high-temperature or subject to the high-temperature heat treatment after being filled with a liquid followed by being cooled to room temperature; 2 ○ the case where the pressure within the sealec-up tightly container filled with the contents becomes higher than that outside of the container; and 3 ○ the case where the pressure within the sealed-up tightly container becomes equal to that outside of the container. According to the present invention, (A) At first, in the case where the contents are held under the depressurized condition as shown in the above described 1 ○, in order to prevent at least the packing from being rotated together with the cap when cap is loosened, air reservoirs 12 are formed in the upper surface of the packing or in the lower surface of the top wall opposite to the upper surface of the packing. As shown in for example Fig. 2, said air reservoirs 12 comprising a plurality of grooves 13 formed concentrically in the circumferential direction (the H-direction) of divided pieces 14 on said divided pieces 14, respectively, circular concave portions 15 surrounded by the respective divided pieces 14 and gaps N between the divided pieces 14 are formed on the upper surface of the packing 9. And, although the air layer naturally remains between the lower surface of the top wall 1 and the packing 9 during the time when the cap is closed, according to the present invention, it is preferable that gaps M are formed in a threaded portion 4 of a mouth portion 3 of container so that the air a, which has passed through said gaps M, may flow in said concave portions 15 and said grooves 13 of the divided pieces 14 through said gaps N between the divided pieces 14 to positively form the air layer between the lower surface of the top wall 1 and the upper surface of the packing 9 during the time when the cap is closed, as shown in Fig. 2. In addition, the air a to the air layer may be supplied by forming gaps in a threaded portion 5 of cap in place of the gaps M formed in said threaded portion 4 of container. (B) Next, in the case where the contents are held under the pressurized condition as mentioned in the above described 2 ○, in order to prevent the packing from being rotated together with the cap when the cap is loosened, a packing 9 provided with a inner sealing member 11 tightly inserted into an inner surface of the mouth of container is used. As shown in for example Figs. 1, 2, said packing 9 is provided with a circular inner sealing member 11 formed in the lower surface thereof. It is preferable that a length L of said inner sealing member 11 inserted is selected as follows in order to improve the airtightness. That is to say, according to the present invention, it is preferable in view of said improvement of the airtightness and the prevention of the packing from being rotated together with the cap that said length L of the inner sealing member inserted is set so as to be a length D from the lower surface of the top wall 1 to the upper end of the circular projection 10 or more (L ≧ D). Although also the packing 9 integrally moves upward with an upward movement of a cap 6 after when the cap is loosened by said distance D by setting the length L of the inner sealing member inserted so as to be said length D or more, the airtightness is held at that position until the bridges are broken. In addition, according to the present invention, in the case where the pressure within the sealed-up container becomes equal to that outside of the container, the packing provided with the inner sealing member as mentioned in the above described (B) may be used or the air reservoir may be formed in the upper surface of the packing or the lower surface of the top wall opposite to the upper surface of the packing, as mentioned in the above described (A), to prevent the packing from being rotated together with the cap. In case of the pilfer-proof cap made of synthetic resins used for sealing up tightly the container holding the contents under the depressurized condition, the inside of the container is depressurized to generate a vacuum there when the container is filled with a liquid heat trated at the high-temperature or subjected to the high-temperature heat treatment after being filled with the liquid followed by being cooled to room temperature, whereby continueing to seal up tightly the mouth portion of container by the packing as long as the force lifting up the packing is not generated. Consequently, even though the cap-loosening action is conducted to an extent of not fully removing the cap by mischief and the like, the air layer is formed between the lower surface of the top wall and the upper surface of the packing by the air reservoir provided in the upper surface of the packing or in the lower surface of the top wall opposite to the upper surface of the packing, so that the packing can be prevented from at least being rotated together with the cap, whereby holding the airtightness within the container at least until the bridges are broken in view of the elongation of the bridges. And, after at least the bridges were surely broken, the packing holding the above described vacuum seal can be lifted up together with the cap by means of the packing guide to open the container. In the case where the contents are held under the pressurized condition, the packing provided with the inner sealing member tightly insertable into the inner surface of the mouth of container is used, so that, even though the cap-loosening action is conducted to an extent of not fully removing the cap by mischief and the like, the packing can be prevented from at least being rotated together with the cap, whereby holding the airtightness within the container. And, after at least the bridges were surely broken, the packing holding the seal can be lifted up together with the cap by means of the packing guide to open the container. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing a condition that a cap is closed in one preferred embodiment of a pilfer-proof cap made of synthetic resins according to the present invention; Fig. 2 is a disintegrated perspective view showing the above described preferred embodiment; Fig. 3 is a partially cut off perspective view showing said cap in an another embodiment; Fig. 4 is a block diagram showing the condition that the cap is closed in the above described preferred embodiment; Fig. 5 is a block diagram showing a condition that the cap is being loosened in the above described preferred embodiment; Fig. 6 is a perspective view showing one modification of a packing in the above described preferred embodiment; and Fig. 7 is a perspective view showing another modification of said packing in the above described preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One preferred embodiment of a pilfer-proof cap made of synthetic resins according to the present invention will be below described with reference to the drawings. But, the present invention is not limited by this preferred embodiment. Referring to Figs. 1 to 3, a pilfer-proof cap made of synthetic resins (hereinafter referred to as a cap) C comprises a cap 6, in which a circular as seen in plan top wall 1 and a annular skirt depending 2 from said top wall 1 are comprised and a threaded portion 5 of cap screwed in a threaded portion of container formed in an outer circumferential surface 3a of a mouth portion 3 of container is provided in an inner circumferential surface 2a of said annular skirt 2, pilfer-proof bands (hereinafter referred to as PP bands) 8, 8 integrally connected with said cap 6 through a plurality of bridges 7, 7, a packing 9 provided in the cap 6 so as to seal up tightly said mouth portion 3 of container during the time when said cap is closed, a packing guide 10 provided between said threaded portion 5 of cap in said inner circumferential surface 2a of the skirt 2 and the top wall 1 so as to be capable of holding an airtightness of the mouth portion 3 of container by said packing 9 until said bridges 7 are broken and lifting up the packing 9 above the mouth portion 3 of container as soon as the bridges 7 are broken when the cap is loosened, a circular inner sealing member 11, by means of which the packing 9 is tightly insertable into an inner surface 3b of the mouth portion 3 of container, and an air reservoir 12, in which the air a is flown from said outer circumferential surface 3a of the mouth portion 3 of container during the time when the cap is closed, formed in an upper surface 9a of the packing 9. Referring to Fig. 2, said air reservoirs 12 formed on the upper surface of the packing 9 comprises a plurality of grooves 13 formed concentrically in the circumferential direction (the H-direction) of divided pieces 14 on said divided pieces 14, respectively, circular concave portions 15 surrounded by the respective divided pieces 14 and gaps N between the divided pieces 14. And, during the time when the cap is closed, the air a, which has passed through gaps M formed in threaded portions 4, 4 of container on an outer circumferential surface 3a of a mouth portion 3 of container, flows in said concave portions 15 and said grooves 13 of the divided pieces 14 through said gaps N between the divided pieces 14 to form the air layer S between the lower surface 1a of the top wall 1 and the upper surface 9a of the packing 9. In addition, said inner sealing member 11 formed in the lower surface of the packing 9 aims at an improvement of the airtightness and the prevention of the packing from being rotated together with the cap and a length L of the inner sealing member 11 inserted into the inner surface of the mouth of the container is set so as to be greater than a length D from the lower surface of the top wall 1 to the upper end of said packing guide 10 (L > D). Moreover, the packing guide 10 comprises a circular projection formed integrally with the cap 6 along the inner circumferential surface 2a of the skirt 2 of the top wall 1. Said circular projection 10 is provided at a position far from the lower surface of the top wall 1 by said distance D, as above described. Furthermore, this cap C is made of thermoplastic synthetic resins, such as polyethylene and polypropylene, by for example the injection molding method and other suitable methods. A plurality of bridges 7 hang at suitable intervals from a bottom edge 20 of the skirt 2 to hold said PP bands 8. And, the PP bands 8 are folded back inward so as to have suitable elasticity to be formed in the form of a plurality of projections 21 at intervals at lower ends thereof. Said projections 21 are engaged with lower engaging portions 22a of shoulder portions 22 provided around the mouth portion 3 of container on the idle end sides thereof under the condition that the cap C is perfectly mounted on the mouth portion 3 of container to mechanically engage the PP bands 8 with the mouth portion 3 of container. Besides, suitable serrations are formed in the outer circumferential surface 2b of the skirt 2. Additionally, referring to Fig. 1, although the threaded portions 4 of container and the threaded portions 5 of cap are continuous in series, respectively, a plurality of them are shown for convenience in the explanation of the cap-opening action. Since the present preferred embodiment has the above described construction, in case of the pilfer-proof cap C made of synthetic resins used for sealing-up tightly the container holding the contents therein under the depressurized condition (A), as shown in Fig. 4, when the cap is loosened from the condition that the cap is closed by applying a turning force to the cap 6 in the cap-opening direction, as shown in Fig. 5, not only the air layer S is formed between the lower surface 1a of the top wall 1 and the upper surface 9a of the packing 9 and as a result the air reservoir or pool 12 is formed, because the air a flows from the outer circumferential surface 3a of the mouth portion 3 of container to the upper surface 9a of the packing 9 (refer to Fig. 2), but also the packing 9 has the circular inner sealing member 11 tightly insertable into inner surface 3b of the mouth portion 3 of container, so that, even though the cap-opening action is conducted to an extent of not fully removing the cap by mischief and the like, the packing 9 can be surely prevented from being rotated together with the cap, whereby holding the airtightness within the container at least until the bridges 7 are broken in view of the elongation of the bridges 7. And, after at least the bridges 7 were surely broken, the packing 9 holding the above described vacuum seal can be lifted up together with the cap 6 by means of the packing guide 10 to open the mouth portion 3 of container. As above described, in the present preferred embodiment, the packing 9 is adapted to hold the airtightness against the mouth portion 3 of container until the bridges 7 are broken when the cap is removed, so that, even though the cap is slightly loosened, the packing 9 is not lifted together with the cap 6 as long as the bridges 7 are not broken. In addition, even in case of the pilfer-proof cap made of synthetic resins used for sealing-up tightly the container holding the contents therein under the pressurized condition (B) in place of case of the pilfer-proof cap made of synthetic resins used for sealing-up tightly the container holding the contents therein under the depressurized condition (A), a construction similar to that in the above described preferred embodiment or a construction that the packing has the inner sealing member having the appointed length tightly insertable into the inner surface of the mouth portion of container can exhibit the effects similar to those in the above described preferred embodiment. Moreover, although the so-called one piece-type PP cap, in which the cap is integrally connected with the PP bands through the bridges and the like, was concerned in the above described preferred embodiment, the present invention can be applied also to the so-called two piece-type PP cap in which the cap and the PP bands are separately formed and integrated before being mounted on the mouth portion of container. Furthermore, modifications of the air reservoir are shown in Figs. 6, 7. Referring to Fig. 6, the divided pieces 14 having a plurality of grooves 13 in the radial direction (the R-direction), respectively, and the circular concaved portions 15 surrounded by the respective divided pieces 14 are formed in the upper surface of the packing. Referring to Fig. 7, the circular concaved portions 15 formed in the upper surface of the packing are surrounded by the divided pieces 14 having a rough surface, respectively. It goes without saying that the air reservoir or pool similar to that shown in Figs. 2, 6 and 7 may be formed also in the lower surface of the top wall. Besides, the divided pieces may be not only provided with the concentrical grooves formed in the circumferential direction (the H-direction), provided with the grooves formed in the radial direction (the R-direction), or the rough surfaces, as above described, but also provided with checkerboard-like grooves (so-called roulette-like grooves). In short, it is sufficient that the packing can be prevented from being rotated together with the cap. As above described, in case of the pilfer-proof cap made of synthetic resins used for sealing up tightly the container holding the contents under the depressurized condition, the inside of the container is depressurized to generate a vacuum there when the container is filled with a liquid heat treated at the high-temperature or subjected to the high-temperature heat treatment after being filled with the liquid followed by being cooled to room temperature, whereby continueing to seal up tightly the mouth portion of container by the packing as long as the force lifting up the packing is not generated. Consequently, even though the cap-loosening action is conducted to an extent of not fully removing the cap by mischief and the like, the air layer is formed between the lower surface of the top wall and the upper surface of the packing by the air reservoir provided in the upper surface of the packing or the lower surface of the top wall opposite to the upper surface of the packing, so that the packing can be prevented from at least being rotated together with the cap, whereby holding the airtightness within the container at least until the bridges are broken in view of the elongation of the bridges. And, after at least the bridges were surely broken, the packing holding the above described vacuum seal can be lifted up together with the cap by means of the packing guide to open the container. In the case where the contents are held under the pressurized condition, the packing provided with the inner sealing member tightly insertable into the inner surface of the mouth portion of container is used, so that, even though the cap-loosening action is conducted to an extent of not fully removing the cap by mischief and the like, the packing can be prevented from at least being rotated together with the cap, whereby holding the airtightness within the container. And, after at least the bridges were surely broken, the packing holding the seal can be lifted up together with the cap by means of the packing guide to open the container. Consequently, the effects occur in that the airtightness of the container can be held by the simple construction even though the cap is slightly loosened and thus the contents can be surely protected.

Claims: A pilfer-proof closure device made of synthetic resins, having: a cap (6) including a top wall (1) and a skirt (2) depending from said top wall (1), an inner circumferential surface (2a) of said skirt (2) being provided with a threaded portion (5) capable of being screwed on a threaded portion (4) of a mouth portion (3) of a container to be closed; a pilfer-proof band (8) integrally connected with said cap (6) through a plurality of bridges (7) a packing (9) for sealing up tightly said mouth portion (3); an air reservoir (12) defined between an upper surface of said packing (9) and a lower surface of said top wall (1) for preventing said packing (9) from being rotated together with said cap (6); and a packing guide (10) provided at said cap (6) and capable of lifting up said packing (9) above said mouth portion (3); said packing guide (10) functions so that said packing (9) preserves airtightness of said mouth portion (3) until said bridges (7) are broken when said cap (6) is loosened and so that said packing (9) is lifted up above said mouth portion (3) by said packing guide (10) when said bridges (7) are broken: and said packing (9) is provided with a circular inner sealing member (11) tightly insertable into said mouth portion (3) so that an outer circumferential surface of said inner sealing member (11) is in airtight contact with an inner circumferential surface of said mouth portion (3); characterized in that said upper surface of said packing (9) and said lower surface of said top wall (1) are vertically spaced from each other at a central portion and only contact each other substantially along a peripheral portion so as to form said air reservoir (12); and a length (L) of said inner sealing member (11) is set to be greater than a length (D) from the lower surface of the top wall (1) to the upper end of said packing guide (10). A pilfer-proof closure device according to claim 1, characterized in that said upper surface of said packing (9) and said lower surface of said top wall (1) contact each other along said peripheral portion throught a plurality of rought surface contacts between said packing (9) and said top wall (1). A pilfer-proof closure device according to claim 1, characterized in that said upper surface of said packing (9) and said lower surface of said top wall (1) contact each other along said peripheral portion through a plurality of surface contacts having a plurality of grooves between said packing (9) and said top wall (1). A pilfer-proof closure device according to claim 3, characterized in that said grooves are concentric. A pilfer-proof closure device according to claim 3, characterized in that said grooves are radial. A pilfer-proof closure device according to any one of the preceding claims, characterized in that said packing guide (10) includes a circular projection formed integrally with or separately from said cap (6). A pilfer-proof closure device according to any one of the preceding claims, characterized in that said packing guide (10) is a part of said threaded portion (5) of said cap (6). The use of a pilfer-proof closure device according to any one of the preceding claims, characterized in that pressure within a sealed container is lower than that outside of said sealed container when said cap is closed. The use of a pilfer-proof closure device according to any one of the preceding claims, characterized in that pressure within a sealed container is higher than or equal to that outside of said sealed container when said cap is closed.

Inventors: TAKANO TAKAFUSA, TAKANO, TAKAFUSA
Applicants: NIHON YAMAMURA GLASS CO LTD, NIHON YAMAMURA GLASS CO., LTD.
Application year: 1995
Main classification: B65D41
IPC codes: B65D41, B65D53