BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a half-sectional side view illustrating a major portion of a package of the present invention;
FIG. 2 is a view illustrating, on an enlarged scale, a portion where a liner of a the cap and the open end of the container mouth portion are closely contacted to each other in the package;
FIG. 3 is a half-sectional half-side view illustrating a preferred cap used in the package of the present invention;
FIG. 4 is a view illustrating a process for removing the cap from the container mouth portion by opening the package of the present invention;
FIG. 5 is a sectional view illustrating a major portion of a preferred cap used for the package of the present invention together with the container mouth portion in a state before the mouth portion is wrap-seamed with the cap; and
FIG. 6 is a sectional view illustrating a major portion of a preferred cap used for the package of the present invention together with the container mouth portion in a state before the mouth portion is wrap-seamed with the cap.
PREFERRED EMBODIMENTS OF THE INVENTION
Preferred embodiments of the cap constituted according to the present invention will now be described in detail with reference to the accompanying drawings.
Referring to FIGS. 1 and 2, a package of the present invention is constituted by a metallic container having a mouth portion generally designated at 1 and a cap generally designated at 3.
An open end of the container mouth portion 1 includes an upper curled portion 1a formed at an upper end thereof, a side wall portion 1b hanging down vertically from the upper curled portion 1a and a lower curled portion 1c extending inward from the lower end of the side wall portion 1b (see FIG. 2). Further, a shoulder portion 5 is formed on the lower side of the open end of the container mouth portion 1, the shoulder portion 5 extending downward and being tilted outward. A screw thread 7 is formed on the lower side of the shoulder portion 5, and a flange portion 9 is formed on the lower side of the screw thread 7.
The metallic cap 3, on the other hand, includes a top panel 10 and a skirt 11 hanging down from the circumferential edge of the top panel 10. Horizontal slits 12 for venting are formed in the upper portion of the skirt 11 maintaining a suitable gap, and a tamper evident band (TE band) 15 is formed at the lower end of the skirt 11 via a breakable bridge 13 (see FIG. 2). A plastic liner 17 is adhered and fixed to the inner surface of the top panel 10.
As will be understood from FIG. 1, a screw thread 19 is formed on the skirt 11 to engage with the screw thread 7 that is formed on the mouth portion 1 of the container, and the cap 3 is firmly fixed to the mouth portion 1 of the container due to the engagement of the threads. Further, the lower portion of the TE band 15 is draw-formed to engage with the flange portion 9 of the container mouth portion 1.
An outer ring 20 that is hanging down is formed at an outer circumferential end of the liner 17, and an inner ring 21 that is also hanging down is formed maintaining a gap to the outer ring 20. The open end of the container mouth portion 1 enters into a space between the outer ring 20 and the inner ring 21 to accomplish a predetermined sealing.
In the package of the above structure, if the metallic cap 3 is turned in the direction of opening, the engagement of threads is released and the skirt 11 rises permitting the cap 3 to be removed from the container mouth portion 1. Here, however, the TE band 15 remains engaged with the flange portion 9 of the container mouth portion 1, and is limited from rising. Therefore, if the cap 3 is opened, the bridge 13 connecting the TE band 15 breaks. As a result, the TE band 15 is cut away from the cap 3 that is removed from the container mouth portion 1, and the fact that the cap 3 is opened can be recognized.
Here, at the time of opening, if the sealing by the liner 17 is broken before the bridge 13 connecting the TE band 15 is broken, then the tamper evidence becomes unsatisfactory. Therefore, it becomes necessary to have the sealing broken after the bridge 13 is broken. Further, it often happens that the cap 3 that is once opened and removed from the container mouth portion 1 and from which the TE band 15 has been separated away, is used again being fitted (i.e., resealed) to the container mouth portion 1. To satisfy the above requirement according to the present invention, the liner 17 has a structure as described below.
That is, referring to FIGS. 2 and 3, a region X that does not adhere to the inner surface of the top panel 10 is formed along the outer circumferential edge portion of the liner 17. The liner 17, therefore, is adhered and fixed to the inner surface of the top panel 10 at portions except the region X. The region X that does not adhere is for forming a favorably sealed structure by the draw working that will be described later.
Further, the inner surface 20a of the outer ring 20 of the liner 17 extends straight in the vertical direction. The surface between the lower end of the inner surface 20a and the lower end of the outer surface 20b of the outer ring 20 is forming a tapered surface 20c being tilted downward from the side of the inner surface 20a toward the side of the outer surface 20b.
Further, the sealed structure is formed by draw-forming the corner portion from the top panel 10 to the skirt 11 while pushing the cap 3 from the upper direction in a state where the cap 3 is placed on the mouth portion 1 of the container that is filled with a predetermined content and the open end of the container mouth portion 1 is inserted in a space between the outer ring 20 and the inner ring 21. By using a predetermined jig, further, the skirt 11 and the TE band 15 are so formed as to comply with the outer surface of the container mouth portion 1. Therefore, the screw thread 19 is formed on the skirt 11 so as to engage with the screw thread 7 of the container mouth portion 1, and the TE band 15 engages at its lower end with the flange portion 9 that is formed on the container mouth portion 1.
According to the present invention, the region X that does not adhere is formed along the outer circumferential edge portion of the liner 17. Therefore, the draw-forming can be easily accomplished as described above, the surface between the outer ring 20 and the inner ring 21 of the liner 17 comes into close contact with the upper curled portion 1a of the open end of the container mouth portion 1, the inner surface (vertical surface) 20a of the outer ring 20 comes into close contact with the outer surface of the side wall portion 1b formed at the open end of the container mouth portion 1, and an inner protruded portion 23 protruding inward is formed at the lower end of the inner surface 20a of the outer ring 20 so as to come into close contact with the outer portion of the lower curled portion 1c of the container mouth portion 1, to thereby form the sealed structure.
The inner ring 21 is for accomplishing the centering when the cap 3 is placed on the open end of the container mouth portion 1. The outer surface of the inner ring 21 is in slight contact with the inner surface of the open end of the container mouth portion 1 but does not directly take part in the sealing structure.
Referring to FIG. 4, when the cap 3 forming the liner 17 as described above is opened, the inner protruded portion 23 formed at the lower end of the inner surface 20a of the outer ring 20 rises maintaining a close contact with the outer surface of the side wall portion 1b of the open end of the container mouth portion 1 (FIG. 4(a)). As the cap 3 is further opened, the inner protruded portion 23 comes into close contact with the upper curled portion 1a of the open end of the container mouth portion 1 (FIG. 4(b)). Finally, the inner protruded portion 23 separates away from the upper curled portion 1a, whereby the sealing is broken and the cap 3 is removed from the container mouth portion 1.
That is, when the cap 3 is opened according to the present invention, the sealed structure is maintained until the inner protruded portion 23 formed on the outer ring 20 separates away from the side wall portion 1b of the open end of the container mouth portion 1, and the sealing is not broken within short periods of time after the start of opening. Therefore, the bridge 13 connecting the TE band 15 is broken before the sealing is broken, and the cap 3 of which the bridge 13 has not been broken reliably represents that the sealed structure has not been broken. Thus, a favorable tamper evidence is maintained. According to the present invention, therefore, it is desired that the length L of the side wall portion 1b of the open end of the container mouth portion 1 (see FIG. 2) is set to be from 0.5 to 2.3 mm. If the length is too small, the time becomes short from the start of opening to the breakage of sealing, and the bridge 13 tends to be easily broken after the sealing is broken.
The cap 3 once removed from the container mouth portion 1 and from which the TE band 3 has been separated away, can be resealed as described below. Namely, the cap 3 is placed on the open end of the container mouth portion 1 and is turned in the direction of sealing. The cap 3 finally descends to the lowermost state shown in FIG. 2 from the state of FIG. 4(b) through the state of FIG. 4(a) to form the sealed structure again. According to the present invention, the surface between the lower end of the inner surface 20a and the lower end of the outer surface 20b of the outer ring 20 is forming a tapered surface 20c being tilted downward. Therefore, the tapered surface 20c works to easily guide the liner 17 into the positional relationship shown in FIG. 4(b) enabling the above-mentioned resealing to be smoothly accomplished. For example, if the above tapered surface 20c is not formed, and the surface between the lower end of the inner surface 20a and the lower end of the outer surface 20b of the outer ring 20 is forming a horizontal surface, then this surface is caught by the upper curled portion 1a of the open end of the container mouth portion 1, making it difficult to smoothly accomplish the resealing and requiring a very large torque for the sealing. The tapered surface 20c does not necessarily have to continue from the lower end of the inner surface 20a to the lower end of the outer surface 20b of the outer ring 20, but may be formed on the side of the inner surface 20a. It is further desired that the lower end of the inner surface 20a of the outer ring 20 is formed in an arcuate shape from the standpoint of improving the resealing performance.
In the present invention, it is desired that the tapered surface 20c has a tapered angle θ (see FIG. 2) in a range of 10 to 70 degrees with respect to the horizontal plane. If the tapered angle θ lies outside the above range, the tapered surface 20c fails to exhibit the guide function to a sufficient degree, and the resealing performance may decrease. It is, therefore, desired that the surface between the lower end of the inner surface 20a and the lower end of the outer surface 20b of the outer ring 20 of the liner 17 is tilted to a suitable degree (e.g., at an angle θ′ of about 5 to about 50 degrees with respect to the horizontal plane in FIG. 3) in a state before the cap 3 is being fitted to the container mouth portion 1, and assumes the above tapered angle θ in a state where the outer ring 20 is bent inward due to the draw-forming. It is, further, desired that the length of protrusion of the inner protruded portion 23 beyond the outer surface of the side wall portion 1b is in a range of 0.03 to 0.65 mm. If the length is too small, it becomes difficult to maintain the sealed structure at the time of opening. If the length is too great, on the other hand, it becomes difficult to attain the resealing.
As will be obvious from FIGS. 4(a) and 4(b), further, upon forming a gap 26 between the outer circumferential surface of the outer ring 20 and the skirt 11, the outer ring 20 expands outwards at the time of resealing; i.e., the resealing is smoothly accomplished.
Referring to the region X that does not adhere to the inner surface of the top panel 10 formed along the outer circumferential edge portion of the liner 17, further, it is desired that the inner end portion X′ thereof (see FIG. 2) is positioned in a range of from −5 to +3 mm with the vertex A of the upper curled portion 1a of the open end of the container mouth portion 1 as a reference. If the inner end portion X′ of the region X that does not adhere extends inward to an excess degree, the outer ring 20 becomes too flexible. When the cap is opened, therefore, the inner protruded portion 23 does not come in close contact with the side wall portion 1b or the upper curled portion 1a to a sufficient degree, and the sealing may be broken before the bridge 13 is broken. Further, the outer circumferential portion of the liner corresponding to the region X that does not adhere may hang down, and the cap may not often be fitted well to the container mouth portion. If the inner end portion X′ of the region X that does not adhere is positioned outwards to an excess degree, on the other hand, the length of the region X that does not adhere becomes too small, the outer ring 20 deforms only to a small degree at the time of draw-forming, and it becomes difficult, for example, to form the inner protruded portion 23.
The above liner 17 is obtained by, for example, forming a shell which comprises a top panel and a skirt, dripping a molten resin which is a liner-forming material onto a predetermined portion of the top panel in a state where an adhesive and a parting agent have been applied thereto, and pressing the molten resin.
According to the present invention, further, it is desired that the liner 17 is formed in a shape as shown in FIGS. 5 and 6 in order to heighten the opening performance while requiring a decreased torque for the opening.
That is, FIGS. 5 and 6 are sectional views illustrating major portions of the liners 17 in a state before the cap 3 is fixed to the container mouth portion 1 by wrap-seaming it. In an example of FIG. 5, a recessed portion 25 is formed in the surface positioned between the outer ring 20 and the inner ring 21 at a portion positioned on the side of the inner ring 21. In an example of FIG. 6, too, a recessed portion 25 is formed in the surface positioned between the outer ring 20 and the inner ring 21 at a portion positioned on the side of the outer ring 20. In these examples, when the cap 3 is fitted to the container mouth portion 1 as shown in FIGS. 1 and 2, the recessed portion is crushed, the surface positioned between the outer ring 20 and the inner ring 21 assumes a state of being press-contacted to the upper curled portion 1a of the open end of the container mouth portion 1. In either case, the closely contacting force decreases between the above surface and the upper curled portion 1a. This decreases the frictional force that hinders the opening. Accordingly, a decreased torque is required for the opening facilitating the opening.
In the example of FIG. 6, however, in press-forming the liner 17, the outer ring 20 formed on the lower side of the region X that does not adhere may be pulled by the metal mold at the time of removing the mold after the forming. Therefore, the outer ring 20 may hang down from a portion corresponding to the recessed portion 25, and may poorly fit to the to the container mouth portion at the time of fitting. From the standpoint of forming, therefore, it is best suited to form the recessed portion 25 in the portion positioned on the side of the inner ring 21 as shown in FIG. 5 to enhance the opening performance.
Patent Application
20080073309
