EP0000091B1 - Improved pressure release closure - Google Patents

Improved pressure release closure Download PDF

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Publication number
EP0000091B1
EP0000091B1 EP78300012A EP78300012A EP0000091B1 EP 0000091 B1 EP0000091 B1 EP 0000091B1 EP 78300012 A EP78300012 A EP 78300012A EP 78300012 A EP78300012 A EP 78300012A EP 0000091 B1 EP0000091 B1 EP 0000091B1
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EP
European Patent Office
Prior art keywords
closure
tab
pouring
closure member
force
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP78300012A
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German (de)
English (en)
French (fr)
Other versions
EP0000091A1 (en
Inventor
Michael Debenham
Allan George Dalli
Peter Lewis Revill
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Broken Hill Pty Co Ltd
Original Assignee
Broken Hill Pty Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Broken Hill Pty Co Ltd filed Critical Broken Hill Pty Co Ltd
Priority to EP81100016A priority Critical patent/EP0032115B1/en
Priority to DE8181100016T priority patent/DE2862374D1/de
Publication of EP0000091A1 publication Critical patent/EP0000091A1/en
Application granted granted Critical
Publication of EP0000091B1 publication Critical patent/EP0000091B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D51/00—Making hollow objects
    • B21D51/16—Making hollow objects characterised by the use of the objects
    • B21D51/38—Making inlet or outlet arrangements of cans, tins, baths, bottles, or other vessels; Making can ends; Making closures
    • B21D51/383—Making inlet or outlet arrangements of cans, tins, baths, bottles, or other vessels; Making can ends; Making closures scoring lines, tear strips or pulling tabs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D17/00—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions
    • B65D17/28—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness
    • B65D17/401—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness characterised by having the line of weakness provided in an end wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2205/00—Venting means

Definitions

  • This invention relates to improvements in easy opening closures, and more particularly to improvements in pressure releasing vent closures of the type presently used in can ends having push-in closures.
  • Cans containing highly carbonated beverages including those having venting closures as shown in Figure 1 are liable to gush or spurt on being opened, especially where the beverage in the can tends to froth.
  • the problem is aggravated when the can is tilted during the opening operation since this often means that the liquid in the can is close to or covers the venting closure whereby the escaping gas is more likely to entrain some of the liquid or froth in the can.
  • the problem is even more aggravated where the can is roughly handled prior to the opening thereof since agitation causes the release of carbon dioxide into the can head space, thereby generating froth.
  • U.S. Patent 2,261,117 to Jack, Jr. discloses a push-in closure comprising a single closure member.
  • the closure member is formed by forming a bulge in the container member, severing around the bulge to form a severed bulged tab, and then flattening the bulged tab to place the cut edges thereof and the marginal portions surrounding the opening in overlapping relationship. A seal is formed between the overlapped portions.
  • One embodiment of the invention provides a closure member which can be used on a container for a carbonated beverage but the closure member does not reseal after it has been opened by the application of a digitally applied push-in force.
  • the second embodiment is for a closure member which can reseal after it has been opened by the application of a digitally applied push-in force but this form of closure member is not suitable for use on a container for a carbonated beverage.
  • U.S. Patent 3,334,775 to Klein et al. discloses a gated can lid wherein the gate is depressible into the container by digitally applied push-in force.
  • the container has a single gate therein, but the patentees describe, at column 4, lines 62-66, an arrangement wherein a portion of the gate panel might be folded inwardly from each end to provide a specific pouring portion and a venting portion, with the section of the gate panel between these portions remaining in position.
  • Klein et al. do not disclose or suggest a resealable venting member.
  • U.S. Patent 3,741,432 to Werth et al. and Australian Patent No. 475,951 each disclose a closure tab for a container, with a pressure release tab formed in the closure tab. Manual pressure applied to the pressure release vent tab is transferred to the closure tab. Both the release vent tab and the closure tab are depressible by the pressure of the user's thumb applied to the release vent closure tab and transmitted to the closure tab in a single operation which first exposes the release vent and then the closure or vent opening.
  • Werth et al. have no suggestion that the pressure release vent tab disclosed therein is resealable upon the release of digitally applied push-in force.
  • the entire thrust of the Werth et al. patent is to permit the pressure to be vented and the pouring opening to be opened in one operation without withdrawing a digit from the tab area.
  • U.S. Patent 3,958,717 to Ellis discloses a push-in, easy opening closure which includes a pouring tab and a vent tab.
  • the tabs are integrally connected to the can lid by a hinge area, and share a common hinge area, with the tabs extending in opposite direction from the common hinge area.
  • the patentees indicate that this construction results in an appearance similar to a conventional ring-pull end, so special instructions would not be required to educate the consumer, and also with the tabs located immediately adjacent to each other the can can be opened with a minimum of finger movement. There is no suggestion that the vent tab reseals itself upon the removal of finger pressure applied thereto.
  • U.S. Patent No. 4,033,275 to Radtke discloses a beverage can end having a vent tab and a pour tab, generally similar to the design of U.S. Patent No. 3,958,717, except the tabs do not share a common hinge area, but instead are disclosed as remote from one another.
  • the present invention provides a push-in pressure releasing closure in a container member suitable for liquids under pressure
  • a closure member formed integrally from a portion of the container member and defined by at least a weakening line and being of dimensions capable of being opened by a digitally applied push-in force against the action of said pressure
  • said closure member having an operating portion which is adapted in use to have said push-in force applied thereto and a connection to said container member, characterised in that means are provided for substantially preventing permanent opening of said closure member by an unrestrained digitally applied push-in force whereby said closure member substantially returns to its closed position in the absence of said digitally applied push-in force to such an extent as to inhibit the escape of froth and/or liquid under pressure from within said container member.
  • the invention also provides a can end for a container suitable for liquids under pressure, including a liquid pouring closure and a pressure releasing closure in said end to be opened by a digitally applied push-in force characterised in that said pressure releasing closure co-operates with the portion of the can end surrounding said pressure releasing closure to physically limit the unrestrained depression of said pressure releasing closure by said digitally applied push-in force to cause said pressure releasing closure to return substantially to its closed position in the absence of said digitally applied push-in force to such an extent as to inhibit the escape of froth and/or liquid under pressure from within said container.
  • the improved pressure releasing closure may be achieved in several ways.
  • the extent to which the operating portion is raised and/or the effective area of the pressure releasing closure member available for actuation may be selected so as to prevent deflection by a digitally applied force beyond the angle at which the elastic limit of the metal at said connection is exceeded, thereby preventing permanent opening of the closure member by finger or thumb pressure.
  • the connection may be arranged at a remote position relative to the operating portion compared to the prior art arrangement, in which the hinge is right at the periphery of the operating portion, and the closure member cannot be opened sufficiently to deform beyond its elastic limit the metal defining the connection.
  • the pressure releasing closure is formed at the narrow end of a generally pear shaped pouring closure hinged to the container end about its wide end, said pressure releasing closure being partly severed from said pouring closure except for a narrow connection about which the pressure releasing closure flexes during the pressure releasing opening thereof, said pressure releasing closure being raised to such an extent or being of an effective size such as to prevent permanent opening thereof by finger or thumb pressure.
  • the thumb or finger is likely to cover the hole formed on opening the venting closure. This has been found to result in undesirable opening characteristics being introduced by the user since the tendency is for the user to remove the thumb or finger as soon as gas escape is detected.
  • the escape of gas can occur as soon as the closure is opened while the escape of spurting liquid can be prevented by releasing the opening force on the closure member, and controlled escape achieved by releasing the gas and/or froth in short bursts.
  • the pressure releasing closure member is formed as an extension on a pouring closure, with the openings being closed by the respective closures preferably being interconnected to form a single opening.
  • the pressure releasing closure operates in the manner described above but is removed from its opening when the pouring closure is opened thus providing a venting opening by means of which the contents of the can may be vented during the pouring operation.
  • the operating portion is located at one end of a relatively narrow elongated portion extending from the connection to the container member.
  • the closure not be depressed into the opening with which the closure is associated to an extent as to exceed the elastic limit thereof.
  • the closure By causing the closure to depress into the beverage can or other container upon the application of digitally applied push-in force thereto, with flexing of the closure about the connection, without exceeding the elastic limit of the connection, the closure will be returned at least substantially to its original position, thereby to reseal the container against further escape of froth or liquid therefrom.
  • the internal pressure within the container aids in the resealing of the closure.
  • the exact amount of depression which a given closure can experience without the elastic limit of the connection thereof being exceeded will depend upon a number of variables, such as the size of the closure, the thickness of the metal, the type of the metal, the effective length of the connection, and the like. Generally, it is not possible to specify an exact amount of closure deflection which can be encountered before the elastic limit of the connection is exceeded. However, in general terms the amount of angular depression of the closure may be more readily appreciated from consideration of the following simulated test.
  • a closure was formed in a sheet of 5082 Aluminum, having a thickness of 0.15 inches.
  • the closure was of the design set forth in Figure 6, with the central cut being located 0.016 inches from the center of the closure.
  • the free or cut edges of the sides of the closure were located approximately 0.015 inches from the center of the closure.
  • the end of the closure furthest removed from the connection was deflected into the simulated can a distance of 0.030 inches, corresponding to an angular deflection of 5.5°, and upon removal of the deflecting pressure the closure returned to approximately its original position.
  • a deflection of 0.035 inches still resulted in the return of the closure to approximately its original position - that is, the elastic limit of the connection was not exceeded.
  • the closure upon depressing the closure a distance of 0.040 inches corresponding to an angular deflection of 7.5°, permanent deformation of the connection occurred, and the closure would not return to its original position.
  • This simulated test was conducted by clamping the closure at the hinge line, with the application of force applied to the free edge of the closure which was furthest removed from the hinge line.
  • the angular displacement of the closure must be less than 7.5°, and preferably no more than 5.5 to 6.0°.
  • the depression must be sufficient to permit the escape of pressure from the container interior, and the minimum deflection which will accomplish this result will depend upon a number of variables, including the thickness and type of the sealant applied to the line of severance.
  • FIG. 1 the prior art can end shown in Figure 1 has a pressure releasing/venting closure V and a pouring closure P.
  • Each closure is circular and is integrally hinged at H to the can end at the periphery of the closures.
  • the closures V and P are opened, they hinge about H and since the opening force deflects the closures to such an angle that the elastic limit of the metal forming hinge H is exceeded the closure will remain open once opened.
  • closure V the tab thereof is raised more than the pouring tab to ensure that it can be pushed open to such an extent as to permit adequate venting of the can during pouring.
  • the venting closure V is replaced by a pressure releasing closure 10.
  • the closure 10 comprises a closure member or tab 11 having an operating portion 12 in the form of an upwardly raised button by means of which an opening force can be applied to the closure 10 by a finger or thumb.
  • the tab 11 has a relatively elongate narrow configuration compared to the venting closure V and is integrally connected to the end at 13.
  • the connection 13 does not act as a hinge in use in the same manner as hinges H in Figure 1 operate, and for this reason the connection is described as a connection rather than a hinge.
  • the closure member 11 is of the fully sheared construction described in U.S. Patents No. Re. 28,910 (3,759,206) and 3,931,909, and is formed by the method disclosed therein, or by coining or otherwise expanding the tab and/or by contracting the size of the opening by means of any suitable cold working operation such as coining.
  • connection 13 is remote from the portion 12, it is unlikely that the whole of the closure will be covered by the finger and gas escape openings will be exposed at least along the long sides of the tab 11. Furthermore, the remote positioning of the connection 13 means that the angle to which the tab 11 can be deflected by a digitally applied force will not be so great as to exceed the elastic limit of the metal at the connection 13 so the tab will resume at least substantially its closed position on removal of the opening force. This will of course be assisted by any pressure within the can or by escaping contents. These two factors combined means that in the event that spurting does occur, it can be controlled by means of the closure 10 by removing the opening force and releasing the gas and/or froth in short bursts.
  • closure 10 is likely to be positioned closer to the centre of the can end to reduce the likelihood of liquid being present in the gas released from the can.
  • closures 10 and P will be hermetically sealed by means of sealant (not shown), such as a plastisol, applied to the end in any suitable manner.
  • the arrangement does have one practical disadvantage in that the closure 10, upon the release of the push-in opening force, no longer acts to vent air into the can during the pouring or drinking of liquid therefrom.
  • the problem can however be overcome by adopting any one of the closure configurations shown in Figures 3 to 14 of the drawings.
  • the can end shown in Figures 3 and 4 is formed with a fully sheared closure member surrounded by a generally pear-shaped opening 21 and is hinged to the end at 22.
  • the tab 20 is formed with a raised area 23 extending from the wide end of the tab 20 and a smaller raised area or button 24 adjacent the narrow end of the tab 20.
  • the narrow end of the tab 20 is partly severed from the remainder of the tab 20 along lines 25 and 26 leaving a narrow connection 27 and thereby defining a pressure releasing tab 28.
  • the button 24 in tab 28 is raised to a greater extent than the area 23 so as to be more readily accessible for finger or thumb actuation.
  • the tab 28 may be raised by about 1 mm above the periphery of the tab 20 and it will be noted from the drawing that the tab 20 is level with the raised periphery of the opening 21.
  • the lines of severance 25, 26 allow the pressure releasing tab 28 to be flexed about connection 27 while the height of the tab 28 is selected to prevent permanent deflection after removal of the opening force applied by a finger or thumb. When the opening force is removed, the tab 28 will close to prevent continued spurting in the event that spurting occurs.
  • the closure 20 is easily opened by finger pressure applied to the raised area 23 of tab 20.
  • sealant (not shown) is applied to cover all lines of severance in the closure.
  • the depressed area 29 may be formed by slightly doming the end panel, say by about 1.5 mm, and then flattening the dome to form the area 29.
  • a flat end panel may be formed with the depressed area 29. In this way the tabs 20 and 28 are protected by the upstanding portion 30 of the end panel and the panel is stiffened against outward buckling.
  • the embodiment of Figure 3 effectively combines the separate pressure releasing tab of Figure 2 and a pouring tab, with the tab 20 itself defining the connection between the pressure releasing tab 28 and the can end.
  • the venting opening is opened when the tab 20 is opened thereby overcoming the problem created by the resealing nature of the pressure releasing tab 28.
  • the pressure releasing tab acts in the same manner as described above and therefore alleviates the problems associated with the prior art at least to the same extent as the first embodiment.
  • the configuration of the opening 21 results in acceptable pouring and drinking characteristics.
  • the closure is formed by a modified version of the method described in the patents referred to above. It is not practical under high speed end forming conditions to sever the tab 20 and to form the slits 25 and 26 are separate die stations.
  • a closure tab having lines of severance extending generally transversely to the line of severance of the tab itself by severing the metal along said transverse lines by means of stepped punch and a spring biased die member slidably located within the main die member for severing the tab said spring biased die member being pushed into the main die member as the main severing operation takes place.
  • the stepped punch initially severs the sheet metal along said transverse lines and partly severs the adjacent portion of the tab. Then the slidable die member is pushed into the die whereupon the remainder of the tab is severed.
  • FIG. 5 is a fragmentary schematic sectional elevation of the die components.
  • the die includes a main die member 40 having a cutting face 41 in the shape of the opening 21, and a die member 42 slidably mounted within the main die 40 and biased towards the position shown by means of a spring 43.
  • the slidable member 42 is formed with two cutting faces 44, only one of which is shown, for forming the lines of severance 25,26.
  • a stepped punch 45 having cutting faces 46 corresponding to the cutting faces 44 is arranged to initially engage the slidable member 42 to sever along the lines 25 and 26 and to sever the perimeter of the pressure releasing tab 28. The punch 45 then pushes the slidable member 42 into the die 40 whereupon the punch 45 severs the remainder of the tab 20 from the end.
  • the sheet metal displaced by severing along the lines 25, 26 is returned to the same plane as the remaining metal to ensure that the periphery of the tab is substantially planar. If necessary the metal on either side of each line of severance may be coined to ensure that the slits do not open up.
  • edge of the tab 20 and/or the periphery of the opening 21 may be coined or otherwise worked to increase the overlap between the tab 20 and the surrounding metal.
  • FIG. 6 A modification of the closure of Figures 3 and 4 is shown in Figure 6.
  • the lines of severance 25, 26 are replaced by a central line of severance 25' leaving two spaced connections 27' between the pressure releasing tab 28' and the main tab 20'.
  • the closure is otherwise identical to the embodiment of Figures 3 and 4 and operates in exactly the same manner. However, it has the advantages of having an unsevered periphery and being more resistant to leakage than the embodiment of Figure 3, wherein leakage may occur if the lines of severance 25, 26 are displaced.
  • the unsevered periphery of the closure of Figure 6 results in a less complex die operation in the closure fabrication.
  • the central line of severance may be formed by a so- called "offset shear" die operation.
  • the closure of Figure 6 is formed in the following manner.
  • the end panel is outwardly domed by about 1.5 mm by a die operation or by coining around the periphery of the end panel adjacent the countersink.
  • the area in which the closure is formed is flattened and the sheet metal raised in the region in which the pressure releasing tab 28' is to be formed.
  • the tab 20' is then severed and the initial bulging operation described in the above patents is performed.
  • the tab 20' is raised by a form punch and the metal locally sheared along a line around an edge of the form punch.
  • the bulged metal around the opening is then flattened to form an overlap between the tab and surrounding metal and sealant is applied along all lines of severance.
  • the metal on either side of the line may be coined to ensure that the line does not open.
  • the form punch may be notched so that the line is interrupted over a short distance.
  • a line of weakness such as a score line, may perform the same function.
  • the can end shown in Figures 7 and 8 is formed with a fully sheared closure comprising a pouring closure member or tab 31 hinged to the end at 32 and underlying a pouring opening 33, and a pressure releasing venting closure member or tab 34 secured to the pouring tab by means of an integral neck 35 and extending radially therefrom to underlie a venting opening 36 which opens into the pouring opening 33 over the neck 35.
  • the tabs 31 and 34 are upwardly raised with the tab 34 being raised to a greater extent so as to be more readily accessible to finger or thumb.
  • the tab 34 may be raised by about 1 mm above the periphery of the tab and it will be noted from the drawing that the tab 31 is level with the raised periphery of the opening 33.
  • closure described above is formed by the same method as the closure 10. If necessary the edge of each tab 31 and 34 and/or the periphery of each opening 33 and 36 may be coined or otherwise worked to increase the overlap between the tabs and the surrounding metal.
  • FIG. 7 and 8 effectively combines the separate pressure releasing tab of Figure 2 and a known pouring tab, with the tab 31 defining the connection between the pressure releasing tab 34 and the can end.
  • the venting opening 36 is opened when the pouring tab 31 is depressed thereby overcoming the problem created by the resealing nature of the pressure releasing tab 34.
  • the pressure releasing tab acts in the same manner as described above and therefore alleviates the problems associated with the prior art at least to the same extent as the first embodiment.
  • a raised rib R is formed in the end, for example in the form shown in Figures 7 and 8.
  • the configuration and placement of the rib in the manner shown in the drawings is not essential to the invention since many other configurations and positionings of one or more ribs or beads are envisaged as being just as effective for the purposes described. It will also be appreciated that similar protective rib(s) may be incorporated into the arrangement shown in Figure 2 of the drawings.
  • the positioning of the hinge 32 as shown in Figure 7 is also not essential or even necessarily most preferred.
  • the hinge may be located at the position shown in Figure 3 of the drawings or directly opposite the position shown in Figure 7.
  • the particular configuration of the combined openings 33 and 36 is not essential to the invention.
  • the smoothly rounded nature of the opening over the neck 35 is preferred for aesthetic and practical reasons and it is believed that the configuration shown would provide good drinking and pouring performances.
  • the can end shown in Figures 9 and 10 of the drawings has a fully sheared closure member or tab 50 which overlaps with and underlies the metal surrounding a generally pear shaped opening 51 and is hinged to the end at 52.
  • the tab 50 has a central area 53 which is raised with respect to the periphery of the tab.
  • the raised area 53 is at the same general level as the sheet metal defining the hinge 52 whereby the hinge metal is substantially undeformed by the closure forming process which will be defined in more detail below. Tests carried out to date appear to suggest that the undisturbed nature of the metal at the hinge 52 may well increase the pressure at which peaking or buckling of the end will occur in this general area of the end.
  • the tab 50 has a pressure releasing closure member or tab 55 formed therein in the manner shown in Figures 9 and 10 of the drawings.
  • the tab 55 is formed with an upwardly raised button 56 at the end of a relatively elongate narrow area of metal defining the tab.
  • the tab is connected to the sheet metal defining the tab 50 at 57 and overlaps with and underlies the sheet metal surrounding the sheared opening 58.
  • Both closures are hermetically sealed by means of a sealant (not shown) and the pressure releasing closure operates in the same manner as the pressure releasing closures described above. However, it will be appreciated that in most opening operations the two closures will be opened by means of a single unidirectional push-in force applied in the general area of the raised button 56 on the pressure releasing tab 55.
  • the tab 55 may be located in an inverted position adjacent the narrow end of tab 50 to ensure that relocation of the digit is not required during the opening of tab 50.
  • FIG 11 A further modification of the embodiment of Figure 9 is shown in Figure 11.
  • the pouring tab 50' has an oblate configuration and is located in an inverted position with its hinge 52' located near the centre of the can end.
  • the pressure releasing tab 55' is located within a depressed region 54' in the tab 50' to protect the tab 56' but is otherwise substantially identical to the tab 55.
  • the arrangement of the tabs 50' and 55' in this manner has the advantage of locating the tab 55' nearer to the centre of the can end where the headspace is likely to be greater.
  • the can end is formed with an indentation surrounding the closure 50'. This serves as a sealant well when sealant is applied to the closure 50' and also allows the sheet metal to be clamped to inhibit metal migration when the sheet metal around the opening 51' is coined to create overlap.
  • the can end incorporating the improved closure has an outwardly domed central panel 60.
  • the dome is slightly flat topped for a reason to be described below.
  • the closures 50 and 55 are formed in a downwardly depressed area 61 which extends into the domed end from the hinge area 52 in the same general configuration as the tab 50. The location of the closures 50 and 55 within the depressed area 61 protects the closure 50 against unintentional actuation and to a lesser extent the closure 55 is similarly protected against unintentional actuation.
  • the slight flattening of the dome formed in the end panel 60 increases the height of the dome in the region in which the pressure releasing tab 55 is to be formed thereby increasing the amount of protection afforded to the tab 55 by the adjacent areas of the end panel 60.
  • the end panel 60 is also preferably domed for the following reasons.
  • the doming of the end panel increases the head space of a can to which the end is fitted.
  • the doming of the end panel also increases the rigidity of the end panel.
  • the doming of the end panel will usefully enhance the buckle strength of the converted end. In tests carried out on plain ends it was found that the doming of the end panel between about 1.5 mm and about 3.0 mm increased the buckle strength of the end. Improvement in the buckle strength increased as doming increased.
  • the closures 50 and 55, and 50' and 55' may be formed in a can end blank by any suitable method of piercing and reforming the sheet metal of the end blank. Under normal circumstances the method used would involve several separate die operations, and the punch/die sets used would require the usual stripper plates and die ejectors for ensuring separation between sheet metal and the punch and die components. The use of stripper plates and die ejectors complicates the punch/die sets and the desirability of reducing the number of die operations is obvious.
  • the end panel is formed with a slightly flat topped dome.
  • the dome is downwardly depressed to form the area 61 and to form a small dimple in the region in which the button 56 is to be formed.
  • the dimple is then reformed into the flat topped button 56 by flattening the top of the dimple between two die members.
  • the tabs 50 and 55 are sheared and in the same operation the periphery of the tab 50 is reformed downwardly to form the upwardly raised area 53.
  • Figure 12 is a fragmentary sectional view across the tab 50 but excluding the tab 55.
  • the central portion of the tab remains at the same general level as the unsheared metal defining the hinge 52.
  • the height of the shoulder of metal defined by the sheared portion of the sides of the area 61 is reduced and the angle of the side to the end panel increased to produce some overlap between sheet metal surrounding the opening and the tab 50.
  • the periphery of the tab is coined to increase the area of the tab and further increase the overlap between the tab and the sheet metal surrounding the opening.
  • the sheet metal surrounding the opening 58 is also coined to produce overlap between the opening and the pressure releasing tab 55.
  • the coining of the periphery of the tab 50 is preferably performed at a position close to the shoulder of the raised area 53 so that most of the metal expansion is in the outward direction rather than back towards the centre of the tab. To avoid excessive curling of the periphery of the tab during this operation, the edge of the tab is firmly clinched by die members.
  • the above method of forming the improved closure has several advantages. Firstly, formation of the closure within the downwardly depressed area 61 in the domed central panel provides protection against unintentional opening of the closure. SecondIy, the downward reforming of the periphery of the tab 50 enables its central portion to remain at the same level as the hinge 52 and it is believed that this may well improve the pressure performance of the converted end. This method of forming the tab 50 also enables the pressure releasing tab 55 to be sheared from the tab 50 in the same die operation without any undesirable deformation of the tab 50. To form the same type of closure combination in a flat or upwardly raised area of metal, the shearing of the tabs may result in downward turning of the edges of the larger tab which may need to be flattened or restored in a subsequent die operation.
  • the above method still has the advantage of maintaining the central portion of the tab 50 at the same general level as the unpierced metal defining the hinge.
  • the sheet metal around the periphery of the tabs 50 and 55 and the sheet metal around opening 51 are coined to create the necessary overlap between the tabs 50 and 55 and the sheet metal surrounding them.
  • the overlap can be achieved by the other methods described above.
  • sealant is applied in the regions of the cut edges of the tabs 50 and 55 to hermetically seal the two closures.
  • the above method of forming the improved closure is preferred for several reasons. Firstly the piercing and reforming operations are performed in one die stage thereby reducing the number of stages and excluding tre stripper plates and die ejectors. Secondly, formation of the closure within the downwardly depressed area 61 in the central panel provides protection against unintentional opening of the closure. Thirdly, the downwardly reforming of the periphery of the tab 50 enables its central portion to remain at the same level as the hinge 52 and it is believed that this may well improve the pressure performance of the converted end. This method of forming the tab 50 also enables the pressure releasing tab 55 to be sheared from the tab 50 in the same die operation without any undesirable deformation of the tab 50. To form the same type of closure combination in a flat or upwardly raised area of metal, the shearing of the tabs may result in downward turning of the edges of the larger tab which may need to be flattened or restored in a subsequent die operation.
  • the sheet metal surrounding the opening 51 may be coined to increase the overlap between the tab 50 and the surround.
  • the overlap between the tab 50 and the surround may be produced solely by suitably reforming the shoulder referred to above.
  • the overlap between the pressure releasing closure 55 and the surrounding sheet metal is preferably formed as described above since this enables the button 56 to be made larger and to be located closer to the periphery of the opening 58.
  • the necessary overlap may be produced by coining the periphery of the tab 55.
  • the various closure members described in the earlier embodiments may be formed in substantially the same manner as the modified closure described in the above embodiment.
  • the size of the depressed areas may be reduced to the same size as the area 61 and the upstand surrounding the opening may be flattened as shown in Figure 10.
  • the location of the closure within a depressed area would remove the need to form the protective rib R.
  • the embodiment of the invention shown in Figures 14 and 15 is a modification of the embodiment of Figures 3 and 4 and includes a fully sheared closure member or tab 70, similar to the tab 20 of Figure 3, hinged to the end at 71.
  • the tab 70 has a pressure releasing closure member or tab 72 defined by lines of severance 73 and 74 extending to either side of a raised button 75.
  • the lines 73 and 74 have an included angle of about 60° although it has been found that the tab 72 will operate successfully with the lines 73 and 74 at any included angle within the range of about 30° to 180°, and most successfully between 50° and 70°.
  • the tab 72 flexes about its connection 76 to the tab 70 in the same basic manner as the embodiment of Figures 3 and 4 although it will be noted that the angular nature of the lines of severance 73 and 74 positions the connection 76 more remotely from the raised button 75 than in the case of the embodiment of Figures 3 and 4.
  • the tab 72 is incapable, in normal operation, of being opened by means of a digitally applied force beyond about 3° to 5°. This angle range is below the angle at which the metal at the connection 76 will be permanently deformed so that the tab 72 will in normal use always return to a substantially closed position once the opening force is removed.
  • the tab 70 is formed within a depressed area 77 which is formed in the same basic manner as described above in relation to Figures 9 to 12.
  • the method of formation of the pressure releasing tab 72 is modified to form the lines of severance 73 and 74.
  • the lines of severance 73 and 74 are formed by a stepped punch during an initial stage in the shearing of the tab 70.
  • the remainder of the tab 72 is also sheared and as the punch progresses downwardly, the sides of the tab 70 are reformed downwardly and the tab 70 severed as described in connection with Figure 12.
  • the free edges of the two tabs 70 and 72 are then brought together so that the two tabs are coplanar at the periphery of the tab.
  • the formation of the lines of severance and the downwardly reformed nature of the sides of the tab 70 leaves a step of one material thickness between the tabs 70 and 72 along the inner portions of the lines of severance 73 and 74.
  • the tabs 70 and 72 are coined near their free edges to increase the overlap between them and the surrounding metal.
  • the coin is preferably interrupted at the lines of severance 73 and 74 to ensure free opening thereof during the flexing of the tab 72 about the connection 76.
  • the depressed area 77 may be formed in a flat end panel, as shown in the sectional view of Figure 16, to achieve the same degree of protection without doming the end panel.
  • the closure construction shown in Figures 3 and 4 may be formed by the above method rather than the method described in connection with this embodiment or vice versa. However, the avoidance of moving punch components is preferred.
  • the pressure releasing tab and opening is considerably smaller than the venting tab of the prior art ends and this results in the tab being significantly easier to open than the prior art tabs.
  • the tab V in the prior art end must operate both as a pressure venting tab and an air venting opening and for this reason the tab must either be large enough and/or be raised to such an extent as to be capable of being permanently opened sufficiently to perform the second function. It will be understood that if the tab is small it must be raised further to allow access and if the tab is too small then there will be insufficient metal available to raise it to the extent necessary.
  • the tab in the present invention functions only to release pressure, it is not necessary or desirable to raise it enough to be manually depressed to a position in which it vents the can during pouring since this is achieved, in the second and third embodiments, when the pouring tab is opened. It should be appreciated however that the pressure releasing tab need not be smaller than the tab V in order for the advantages of the invention to be attained.
  • the configurations of the openings shown in the various Figures 3, 6, 7 and 14 are not essential and may be modified without affecting the performance of the closure as described above. It is envisaged that the sides of the pear-shaped opening 21 may be slightly curved outwardly to give the opening a more appealing appearance. Similarly the pressure releasing tab 28 may be used in place of the tab 11 shown in Figure 2 or may be formed in a closure or any other suitable configuration.
  • closures of the present invention can be used in can ends or in other container members, and can be formed of any suitable sheet metal material, including aluminum and steel, and can be of any suitable shape, depending upon the shape of the can body to which the can end or other container member is to be secured. It is also envisaged that the closures may be made in plastics materials by suitable moulding techniques.
  • the pouring closure there is no criticality in the absolute size of the pouring closure, although normally the pouring closure will be of such size as to prevent complete insertion of a user's finger, yet large enough to permit adequate outflow of liquid container contents.
  • the absolute size of the pressure releasing/venting aperture or opening is not critical, but normally the opening will be of a size as to prevent complete insertion of a user's finger, yet large enough to permit adequate outflow of internal container pressure upon pressure releasing, and to permit adequate inflow of air upon venting.
  • the sealant which is used for fully severed closures can be any suitable means or material, such as a sealing compound, plastic tape, adhesive foil, hot melt material, or a combination thereof.
  • a particularly suitable sealing compound is a plastisol-grade polyvinylchloride combined with a conventional plastisizer and compounding ingredients.
  • Such plastisol should be heat curable to form a non-tacky, somewhat yieldable solid material that aids in retaining the closure in place and maintains a hermetic seal under pressures of the magnitudes which normally occur in cans of carbonated and malt beverages.
  • the sealant must be sufficiently frangible to be ruptured upon the application of digitally applied push-in force on the respective closures.
  • the maximum angular displacements of the closure mentioned above apply only to the indicated grade of aluminum, and to the indicated thickness thereof. Changes of these and other variables in the closure construction will change the maximum permissible angle of displacement.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Closures For Containers (AREA)
  • Containers Opened By Tearing Frangible Portions (AREA)
  • Infusion, Injection, And Reservoir Apparatuses (AREA)
  • External Artificial Organs (AREA)
  • Filling Of Jars Or Cans And Processes For Cleaning And Sealing Jars (AREA)
  • Containers And Packaging Bodies Having A Special Means To Remove Contents (AREA)
EP78300012A 1977-06-10 1978-06-02 Improved pressure release closure Expired EP0000091B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP81100016A EP0032115B1 (en) 1977-06-10 1978-06-02 Improved pressure release closure
DE8181100016T DE2862374D1 (en) 1977-06-10 1978-06-02 Improved pressure release closure

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
AU416/77 1977-06-10
AUPD041677 1977-06-10
AU848/77 1977-07-14
AUPD084877 1977-07-14
AU1840/77 1977-09-28
AUPD184077 1977-09-28

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP81100016.5 Division-Into 1981-01-05

Publications (2)

Publication Number Publication Date
EP0000091A1 EP0000091A1 (en) 1978-12-20
EP0000091B1 true EP0000091B1 (en) 1983-09-07

Family

ID=27157041

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78300012A Expired EP0000091B1 (en) 1977-06-10 1978-06-02 Improved pressure release closure

Country Status (14)

Country Link
EP (1) EP0000091B1 (el)
JP (1) JPS5440783A (el)
BR (1) BR7803658A (el)
CA (1) CA1094472A (el)
DK (1) DK152026C (el)
ES (2) ES470541A1 (el)
FI (1) FI68580C (el)
GR (1) GR68086B (el)
IE (1) IE48027B1 (el)
MX (1) MX145578A (el)
NO (1) NO154225C (el)
NZ (1) NZ187328A (el)
PT (1) PT68094A (el)
ZA (1) ZA782900B (el)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU532786B2 (en) * 1979-08-13 1983-10-13 Broken Hill Proprietary Company Limited, The Push - in closure
DE3639428C1 (de) * 1986-11-18 1987-08-27 Rasselstein Ag Verfahren zum Herstellen eines mit einem eindrueckbaren OEffnungslappen versehenen Dosendeckels aus Blech
JPH0282499U (el) * 1988-12-12 1990-06-26
US4930658A (en) * 1989-02-07 1990-06-05 The Stolle Corporation Easy open can end and method of manufacture thereof
US5129541A (en) * 1991-06-04 1992-07-14 Buhrke Industries, Inc. Easy open ecology end for cans
JP6464605B2 (ja) 2013-09-20 2019-02-06 株式会社寺岡精工 ラベル発行装置、および、着脱式容器
JP6917232B2 (ja) 2017-07-24 2021-08-11 株式会社ブリヂストン 空気入りタイヤ
JP6853751B2 (ja) 2017-08-14 2021-03-31 株式会社ブリヂストン 空気入りタイヤ
JP7082027B2 (ja) 2018-10-16 2022-06-07 Ｔｏｙｏ Ｔｉｒｅ株式会社 空気入りタイヤ

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2261117A (en) * 1939-06-09 1941-11-04 Us Can Corp Closure member and method of preparing same

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760752A (en) * 1972-01-07 1973-09-25 J Geiger Easy-opening device for sheet metal containers and the like and method of producing such devices
US3741432A (en) * 1972-01-20 1973-06-26 Coors Container Co Container with closure tab and pressure release tab on closure tab
US3952912A (en) * 1972-03-02 1976-04-27 Walter Merton Perry Container with attached closure
CA1019686A (en) * 1973-05-02 1977-10-25 Michael Debenham Easy-opening closure
DE2347807A1 (de) * 1973-09-22 1975-04-10 Joseph A Geiger Unter fingerdruck oeffnender dosendeckel, insbesondere blechdeckel fuer getraenkedosen
US3889842A (en) * 1974-05-20 1975-06-17 Robert A Bennett Container closure opening means
AU1467476A (en) * 1975-07-16 1977-12-15 Crown Cork & Seal Co Easy-opening can end

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2261117A (en) * 1939-06-09 1941-11-04 Us Can Corp Closure member and method of preparing same

Also Published As

Publication number Publication date
EP0000091A1 (en) 1978-12-20
NO781797L (no) 1978-12-12
PT68094A (en) 1978-06-01
CA1094472A (en) 1981-01-27
ES470541A1 (es) 1979-10-01
FI68580C (fi) 1985-10-10
NO154225B (no) 1986-05-05
DK225578A (da) 1978-12-11
ES476362A1 (es) 1979-08-01
MX145578A (es) 1982-03-08
GR68086B (el) 1981-10-30
FI68580B (fi) 1985-06-28
IE781011L (en) 1978-12-10
JPS621899B2 (el) 1987-01-16
ZA782900B (en) 1979-05-30
NZ187328A (en) 1981-04-24
IE48027B1 (en) 1984-09-05
FI781599A (fi) 1978-12-11
DK152026B (da) 1988-01-25
BR7803658A (pt) 1979-01-09
NO154225C (no) 1986-08-13
DK152026C (da) 1988-07-18
JPS5440783A (en) 1979-03-30

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