EASILY-OPENABLE CONTAINER

Abstract: An easily-openable container includes a container body (9) having an open end (10) and a container end (1) including peripheral wall (5) and a pull tab (6) joined to a lower edge of the peripheral wall (5). The peripheral wall (5) is scored to provide a tear-off line (7) joined to a side edge of the pull tab (6) and is fitted over the open end (10) of the container body (9). The open end (10) of the container body (9) and the peripheral wall (5) of the container end (1) are bonded to each other through a bonded region (17). The tear-off line (7) comprises a continuous first portion (7a,7b,7c) extending from the pull tab (6) along a non-­ bonded region of the peripheral wall (5) above the bonded region (17), a discontinuous second portion (7d) joined to the first continuous portion and extending along the non bonded region of the peripheral wall (5) above the bonded region (17), and a third continuous portion (7e,7f,7g) joined to the second portion and extending along the non-bonded region of the peripheral wall (5) above the bonded region (17).

Description: The present invention relates to an easily-openable container which can be opened by tearing off a scored wall of the container end or cover. There is known an easily-openable container, as disclosed in Japanese Laid-Open Patent Publication No. 60(1985)-193837, which has a container end or cover including an end panel, a peripheral wall joined to and depending from the entire peripheral edge of the end panel, and a pull tab attached to a lower edge of the peripheral wall for removing the container end. The peripheral wall is scored, i.e. cut to provide a tear-off line, substantially fully therearound, the tear-off line being joined to a side edge of the pull tab. The peripheral wall of the container end is fitted over the open end of the container body and bonded thereto to seal in the contents of the container. However, the disclosed easy-open container is disadvantageous in that the contents may flow out whilst the container is being opened by tearing off the scored container end along the tear-off line. If the easy-open container contains a carbonated drink such as beer, a carbonated beverage, or the like under a high internal pressure, and the container end is torn quickly continuously along the tear-off line in an initial stage of the container opening process, a gradual exhaustion of pressurized gas from the container may not be effected. When the contents of the container are not sufficiently cooled and there is a high pressure buildup in the container, a rapid exhaustion of gas is produced due to the high internal pressure as the container is opened. Furthermore, when the pull tab is pulled, the container may be shaken, and the contents may be forced out because of the abrupt release of the internal pressure. As the container end is torn along the tear-off line, the bonded peripheral wall of the container end must be peeled off simultaneously. Therefore, the container body and the tab gripped by the user are moved in directions relatively away from each other with a relatively strong manual force. As the container end is progressively torn along the tear-off line, the peripheral wall thereof joined to the pull tab is peeled off the container body, and the distance between the container and the pull tab is increased. Since the starting and terminal ends of the tear-off line are not connected to each other, even when the container end is torn to the end of the tear-off line, a portion of the peripheral wall which extends between the starting and terminal ends of the tear-off line remains bonded to the container body. The container end can be fully opened or removed from the container body only when the remaining bonded portion of the peripheral wall is completely peeled off. When the remaining bonded portion of the peripheral wall is peeled off, the force which has been applied to the pull tab which is then distant from the container body is abruptly released, causing the container body to be shaken and the contents of the container to flow out. It is an object of the present invention to provide an easily-openable container which prevents the contents from flowing out of the container as the scored container end or cover is torn off along a tear-off line. Another object of the present invention is to provide an easily-openable container which allows reliable exhaustion of gas and prevents the contents from flowing out during the initial stage of the container opening process, especially when the internal pressure in the container is high. A further object of the present invention is to provide an easily-openable container including a scored container end or cover which can be torn off along a tear-off line without causing an abrupt shaking of the container, thereby substantially preventing the contents from flowing out of the container. Accordingly one aspect of the present invention provides a container comprising: (1) a first part comprising the body of the container (9) having an open end; (2) a second part comprising a container end for said container body for sealably closing said open end of said container body, said container end comprising:- (i) an end panel having a peripheral edge; (ii) a peripheral wall joined to and depending from said peripheral edge of said end panel; (iii) a pull tab joined to a lower edge of said peripheral wall; said peripheral wall being scored to provide a tear-off line substantially around the perimeter of said peripheral wall, said tear off line extending from a side edge of said pull tab and said peripheral wall fitting around a marginal portion of the container body adjacent the open end; (3) a bonded region by means of which the outer surface of said marginal portion of the open end of the container body is bonded to the inner surface of said peripheral wall of said container end, characterised in that said tear-off line comprises: (i) a continuous first portion extending through the bonded region from the side edge of said pull tab to and along a non-bonded region of said peripheral wall which is above said bonded region; (ii) a discontinuous second portion contiguous with said first portion extending along said non-bonded region of said peripheral wall which is above said bonded region; (iii) a continuous third portion contiguous with said second portion at least a part of which extends along said non-bonded region of said peripheral wall which is above said bonded region. In a first embodiment of the invention said third portion of the tear-off line includes a segment extending substantially arcuately from said non-bonded region above said bonded region into said bonded region and back again into said non-bonded region. In a second embodiment of the invention the starting end of said first portion and the terminal end of said third portion vertically overlap each other and are vertically spaced from each other. In a third embodiment of the invention a notch is defined in said pull tab, said notch being in confronting relation with said first portion of the tear-off line. In a fourth embodiment of the invention the container end comprises a thin metal substrate having a thermoplastic resin layer coated on the outer surface thereof, said tear-off line being defined by at least partly removing said resin layer. When the pull tab is gripped and pulled to tear the peripheral wall in an initial opening stage, since the peripheral wall is less easily torn along the discontinuous second tear-off line portion, the tearing process is slowed down or interrupted at said second discontinuous second portion, and hence the initial opening stage is not abruptly carried out. The interior and exterior of the container thus communicate with each other through a restricted opening defined in and along said second portion in the non-bonded region of the peripheral wall. Gas under pressure gradually leaks from within the container through the opening, so that the container can be sufficiently exhausted without causing the contents to flow out. In the first embodiment, the continuous third portion of the tear-off line includes a tear-off line segment extending from the non-bonded region of the peripheral wall into the bonded region thereof across the upper edge of the bonded region and back into the non-bonded region above the upper edge of the bonded region, and in the second embodiment the first and third portions have starting and terminal ends, respectively, which vertically overlap each other and are vertically spaced from each other. When the peripheral wall is torn from the starting end of the first portion to the terminal end of the third portion, a portion of the peripheral wall remains bonded to the container barrel at the third portion of the tear-off line. The peripheral wall between the starting and terminal ends of the first and third continuous portions of the tear-off line remains bonded to the container body, and the open end of the container body is covered by the end panel. Since the open end of the container body is covered with the container end, the contents are prevented from flowing out of the container. Then, when the pull tab is further pulled beyond the terminal end of the third portion of the tear-off line the container end is swung upwardly about a bonded portion of the peripheral wall along the third tear-off line portion. Therefore, the container barrel is substantially prevented from being shaken, and the contents do not flow out of the container. In accordance with the third embodiment the starting end of the first continuous portion is positioned in confronting relation to a notch defined in the side edge of the pull tab. This arrangement allows the peripheral wall to start to be torn reliably along the first tear-off line portion. In the fourth embodiment the container end preferably comprises a thin metal sheet and a thermoplastic resin layer coated on an outer surface of the thin metal sheet, the tear-off line being defined by partly removing the thermoplastic resin layer. With this arrangement, the fingers of the user will not be injured even when they touch the torn edges of the peripheral wall. Another aspect of the present invention provides a container comprising: a container body having an open end; a container end including an end panel, a peripheral wall joined to and depending from a peripheral edge of said end panel, and a pull tab joined to a lower edge of said peripheral wall, said peripheral wall being scored to provide a tear-off line joined to a side edge of said pull tab, said peripheral wall being fitted over the open end of said container body; a bonded region by which an outer surface of said open end of the container body and an inner surface of said peripheral wall of the container end are bonded to each other; and said tear-off line comprising a continuous portion extending from the side edge of said pull tab through a bonded region of the peripheral wall above said pull tab into a non-bonded region of the peripheral wall above an upper edge of said bonded region, and another continuous portion extending along the non-bonded region of the peripheral wall above the upper edge of said bonded region, said portions of the tear-off line being disconnected from each other in the non-bonded region of the peripheral wall above the upper edge of said bonded region. In accordance with this aspect, no tear-off line is present between the two continuous portions. For a better understanding of the invention and to show how the same may be carried into effect reference will now be made, by way of example only, to the following drawings in which:- Figure 1 is a front elevational view of an easily-openable container according to the present invention; Figure 2 is a side elevational view of the easilyopenable container shown in Figure 1; Figure 3 is a rear elevational view of the container shown in Figure 1; Figure 4 is an enlarged cross-sectional view taken along line IV-IV of the easily-openable container shown in Figure 1; Figure 5 is a diagram illustrating how the tear strength needed to open the container varies as the container end is progressively torn along the tear-off line; and Figure 6 is a perspective view showing the manner in which the easily-openable container is manually opened. Referring now to Figures 1 to 4 in which a container end or cover 1 comprises a metal foil 2 of tin-free steel, aluminium, or the like, and a thermoplastic resin coating 3 of polypropylene, polyethylene, or the like covering the outer surface of the metal foil 2. The container end 1 includes an end panel 4 and a tubular peripheral wall 5 depending from the entire peripheral edge of the end panel 4. As illustrated in Figure 1, a pull tab 6 for removing the container end 1 is integrally formed with the peripheral wall 5 at a lower edge thereof. The peripheral wall 5 is scored substantially fully therearound to provide a tear-off line 7 extending from a side edge of the pull tab 6 on the lower edge of the peripheral wall 5. The inner surface of the container end 1 is coated with a hot-melt adhesive resin layer 8 of polyolefin, polyamide, polyester, or the like. As illustrated in Figure 4, the container body 9 includes a two-piece bottomed cylindrical body portion 11 made of aluminium and having an open end 10, with can coated layers 12 being coated on the inner and outer surfaces of the cylindrical body portion 11. Instead, the container body 9 may comprise a three-piece bottomed cylindrical portion made of tin and tin-free steel, or may comprise a container made of a composite material or glass. The container body 9 has, at the open end 10, a portion 13 of smaller diameter than the cylindrical portion 11. The portion 13 is covered with a cylindrical stiffening member 14 made of a hot-melt adhesive resin and having a substantially U-shaped cross section, the stiffening member 14 extending fully around the open end 10. When the container body 9 is fully closed by the container end 1, the inner surface 16 of the peripheral wall 5 of the container end 1 lies adjacent the outer surface 15 of the open end 10 with the stiffening member 14 interposed therebetween. The hot-melt adhesive resin layers 8 on the inner surface of the peripheral wall 5 and the stiffening member 14 are melted and bonded to each other fully along their peripheral surfaces, thus forming a bonded region 17 between the peripheral wall 5 and the container body 9. The tear-off line 7 is produced by removing the thermoplastic resin coating 3 from the outer surface of the peripheral wall 5, for example, by applying a laser beam to the coating 3 along a desired pattern. Referring now to Figures 1, 2, 3 and 5, the tear-off line 7 comprises three portions. The first portion includes a segment 7a extending across an extension of, and hence confronting, a notch 6a defined in a side edge of the pull tab 6, a continuous segment 7b joined to the first segment 7a and extending across a region above the pull tab 6, the second continuous segment 7b extending into the non-bonded region above the upper edge 17a of the bonded region 17, and a segment 7c joined to the segment 7b and extending above the upper edge 17a in a peripheral direction of the peripheral wall 5. The peripheral wall 5 is torn along the segment 7c during the initial stage of the container opening process. The second portion comprises a discontinuous segment 7d extending peripherally from the segment 7c. The third portion comprises a segment 7e extending peripherally from the segment 7d, a segment 7f remote from the pull tab 6, connected to the segment 7e and extending arcuately into the bonded region 17 in the peripheral wall 5 and back into the non-bonded region above the upper edge 17a of the bonded region 17, and a segment 7g joined to the segment 7f and extending peripherally along the peripheral wall 5 above the upper edge 17a into a region near the side edge of the pull tab 6. As shown in Figures 1 and 5, the starting end of the tear-off line segment 7a and the terminal end of the tear-off line segment 7g vertically overlap each other, but are vertically spaced from, and hence not connected to, each other. A process of opening the container 18 which container is filled with contents under a high internal pressure will now be described also with reference to Figure 5, which shows how the tear strength needed to open the container 18 varies as the opening process progresses. First, the pull tab 6 is gripped and pulled obliquely upwards in the direction indicated by the arrow. The peripheral wall 5 is torn starting from the notch 6a in its side edge and then into the tear-off line segment 7a. At this stage, the tear strength is relatively high as shown in Figure 5. The tear strength is lowered as the peripheral wall 5 is initially torn along the tear-off line segment 7b, and is increased again as the peripheral wall 5 is progressively torn along the tear-off line segment 7b as far as the tear-off line segment 7c. When the peripheral wall 5 is torn along the discontinuous tear-off line segment 7d, the tear strength is increased further. The tearing-off of the peripheral wall 5 at this stage is thus slowed down or interrupted. In order to tear the peripheral wall 5 along the tear-off line segment 7d as far as the tear-off line segment 7e, therefore, the pull tab 6 must be pulled again. While the pulling of the pull tab 6 is being interrupted or slowed down, since the interior of the container 18 has already been in communication with the exterior thereof through the tear-off line segment 7c which has already been broken, the gas in the container 18 is gradually released under pressure through the restricted opening formed on and along the tear-off line segment 7c. During this initial opening phase, even if the container 18 is shaken, the contents can only flow out through the restricted opening in and along the tear-off line segment 7c. When the peripheral wall 5 is torn along the discontinuous tear-off line segment 7d, the tear strength is repeatedly varied. However, the peripheral wall 5 is torn smoothly and reliably along the discontinuous tear-off segment 7d, after which the peripheral wall 5 is then torn along the tear-off line segment 7e. Then, the peripheral wall 5 is torn along the tear-off line segment 7e and thereafter along the tear-off lines 7f and 7g. When the tearing of the peripheral wall 5 along the tear-off line segment 7g is finished, since the terminal end of the tear-off line segment 7g is not connected to the starting end of the tear-off line segment 7a, the peripheral wall 5 between these ends of the segments 7g, 7a remains joined to the end panel 4. To open the container 18 completely, the pull tab 6 is pulled upwardly toward the end panel 4 as indicated by the arrow in Figure 6. At this time, a portion 5a of the peripheral wall 5 above the tear-off line segment 7f remains bonded to the container 18 at a diametrically opposite position remote from the pull tab 6. While the pull tab 6 is being pulled upwardly, the panel 4 is swung upwardly about the bonded portion 5a, thus removing the container end 1 from the container 18 to fully open the container 18. In this final opening stage, the container end 1 and the container 18 can be separated from each other by only a small uplifting force applied to the pull tab 6. Accordingly, the container 18 does not suffer shaking movements which would otherwise be caused when the force applied to the container 18 is abruptly released. As a consequence, the contents of the container 18 are prevented from flowing out. Even when the peripheral wall 5 is torn all the way along the tear-off line 7, the end panel 4 still covers the open end of the container 18 until the container end 1 is separated from the container 18. Therefore, the contents are also prevented from flowing out even when the container 18 is shaken while it is being opened. The tear-off line segment 7c should preferably be relatively short. If it were unduly long, the region of the peripheral wall 5 which is torn open during the initial opening stage would be large, resulting in an extensive communication between the interior and exterior of the container 18 causing a rapid exhaustion of gas and allowing the contents of the container 9 to flow out. Whilst the container end 1 above described is constructed of the metal foil 2 covered with the thermoplastic resin layers 3, 8, it may equally be constructed of aluminium or the like.

Claims: 1. A container (18) comprising: (1) a first part comprising the body of the container (9) having an open end (10); (2) a second part comprising a container end (1) for said container body (9) for sealably closing said open end (10) of said container body (9), said container end (1) comprising:- (i) an end panel (4) having a peripheral edge; (ii) a peripheral wall (5) joined to and depending from said peripheral edge of said end panel (4); (iii) a pull tab (6) joined to a lower edge of said peripheral wall (5); said peripheral wall (5) being scored to provide a tear-off line (7) substantially around the perimeter of said peripheral wall (5), said tear off line (7) extending from a side edge of said pull tab (6) and said peripheral wall (5) fitting around a marginal portion (19) of the container body (9) adjacent the open end (10); (3) a bonded region (17) by means of which the outer surface (15) of said marginal portion (19) of the open end (10) of the container body (9) is bonded to the inner surface (16) of said peripheral wall (5) of said container end (1), characterised in that said tear-off line (7) comprises: (i) a continuous first portion (7a,7b,7c) extending through the bonded region from the side edge of said pull tab (6) to and along a non-bonded region of said peripheral wall (5) which is above said bonded region (17); (ii) a discontinuous second portion (7d) contiguous with said first portion (7a,7b,7c) extending along said non-bonded region of said peripheral wall (5) which is above said bonded region (17); (iii) a continuous third portion (7e,7f,7g) contiguous with said second portion (7d) at least a part of which extends along said non-bonded region of said peripheral wall which is above said bonded region (17). 2. A container as claimed in claim 1 wherein said third portion of the tear-off line (7) includes a segment (7f) extending substantially arcuately from said non-bonded region which is above said bonded region (17) into said bonded region (17) and back again into said non-bonded region. 3. A container as claimed in claim 1 or 2 wherein the starting end (7a) of said first portion and the terminal end of said third portion (7g) vertically overlap each other and are vertically spaced from each other. 4. A container as claimed in claims 1, 2, or 3 wherein a notch (6a) is defined in said pull tab (6), said notch (6a) being in confronting relation with said first portion of the tear-off line (7a) 5. A container as claimed in any of claims 1 to 4 wherein the container end (1) comprises a thin metal substrate (2) having a thermoplastic resin layer (3) coated on the outer surface thereof, said tear-off line (7) being defined by at least partly removing said resin layer (3). 6. A container (18) comprising: a container body (9) having an open end (10); a container end (1) including an end panel (4), a peripheral wall (5) joined to and depending from a peripheral edge of said end panel (4), and a pull tab (6) joined to a lower edge of said peripheral wall (5), said peripheral wall (5) being scored to provide a tear-off line (7) joined to a side edge of said pull tab (6), said peripheral wall (5) being fitted over the open end (10) of said container body (9); a bonded region (17) by which an outer surface (15) of said open end (10) of the container body (9) and an inner surface (16) of said peripheral wall (5) of the container end (1) are bonded to each other; and said tear-off line (7) comprising a continuous portion (7a,7b,7c) extending from the side edge of said pull tab (6) through a bonded region (17) of the peripheral wall (5) above said pull tab (6) into a non-bonded region of the peripheral wall (5) above an upper edge of said bonded region (17), and another continuous portion (7e,7f,7g) extending along the non-bonded region of the peripheral wall (5) above the upper edge of said bonded region (17), said portions of the tear-off line being disconnected from each other in the non-bonded region of the peripheral wall (5) above the upper edge of said bonded region (17).

Inventors: IIDA, SAKAYU, NAKATA, AKIRA, TERAI, HITOSHI, YOSHIMURA, KUNITOSHI
Applicants: HOKKAI CAN CO., LTD., KIRIN BREWERY COMPANY LTD.
Application year: 1989
Main classification: B65D17
IPC codes: B65D17, B65D41, B65D77