WO1993002932A1

WO1993002932A1 - Full open can end closure

Info

Publication number: WO1993002932A1
Application number: PCT/AU1992/000338
Authority: WO
Inventors: John Alan Walmer Slade; Dietmar Salm
Original assignee: The Broken Hill Proprietary Company Limited
Priority date: 1991-08-08
Filing date: 1992-07-10
Publication date: 1993-02-18

Abstract

A can end closure comprises (i) a panel formed with a rim portion (2) and (ii) a central panel (4) substantially fully severed from the rim portion (2) and having a peripheral free edge portion (5). The rim portion is formed with spaced parallel folded portions defining a groove therebetween within which the peripheral free edge portion (5) of the central panel (4) is positioned. Sealant (8) hermetically seals the central panel (4) to the rim portion (2). A push-in closure C in the central panel (4) comprises a closure tab (10) severed from the panel (4) along a line leaving a hinge portion (12) and has a peripheral free edge portion in overlapping underlying relationship with an edge portion of the central panel (4). Sealant (18) hermetically seals the push-in closure C. An inwardly directed abutment (19) is formed in the central panel (4) adjacent the closure C opposite the hinge (12) and comprises a substantially vertical wall portion (20) defining an anchor point for the tip of the bowl of a spoon inserted in the opening formed in the central panel (4) by inward displacement of the closure C and prevents withdrawal of the spoon as the spoon is levered against the rim portion (2) to deform the central panel (4) and remove it from the rim position (2). The position and arrangement of the abutment ensures that the central panel (4) can be levered from its engagement using a domestic implement such as a spoon.

Description

FULLOPENCANENDCLOSURE

Field of the Invention:

This invention relates to closures for containers, and more particularly to closures of the full-open end type in which substantially all of the end panel is removed when the closure is opened. Background of the Invention:

Most full-open ends currently in use include an end panel which is scored or weakened along a line extending adjacent the rim of the end which is seamed to the can body. Examples of typical full-open end closures of the above types may be found in the Patent literature. It is to be noted that closures of this type usually require a retained lever mechanism by means of which the initial rupturing of the score line is achieved, the lever mechanism usually having a finger opening by means of which the opening disc may be removed from the end panel. Such opening devices are often extremely difficult to manipulate and require a considerable force to be applied to cause the initial rupturing of the score line. Such manipulation is often difficult to achieve, particularly for a woman or child.

The Patent literature contains limited examples (such as U.S. Patent 4003495) of full-open end closures which utilize readily available domestic implements, such as spoons, as levers to assist in opening the end panel. In the example, the removal end panel is formed with a push-in end closure through which a spoon may be inserted to lever the end panel upwardly to break the tear line defining the removable panel. Summary of Invention and Object:

It is an object of the present invention to provide an improved full-open closure for a container member, such as a can end, in which the above described problem is at least ameliorated.

The invention therefore provides a closure for a container member, such as a can end, comprising a panel formed with a rim portion and a central panel adapted for at least substantial removal from the rim portion, said central panel having a closure shaped to receive an opening implement, such as a spoon, and positioned adjacent said rim portion to allow the implement to engage the rim portion in use to lever the central panel from said rim portion, said central panel being formed with a downwardly extending abutment shaped and positioned to provide an anchor point for said implement to prevent said implement withdrawing from said closure during the levering operation.

The abutment preferably comprises an inwardly directed dimple formed in said central panel centrally of and adjacent said closure in said central panel.

The dimple is preferably shaped to have a substantially vertical rear wall portion against which the tip of the bowl of a spoon engages as the bowl is levered against the rim portion to thereby provide said anchor point.

In a particularly preferred form of the invention, the central panel of the closure is at least substantially fully severed from said rim portion and having a peripheral free edge portion, said rim portion having a first fold defining an inner free edge portion and a second oppositely directed fold def ning an edge portion which extends in a spaced generally parallel relationship with said inner free edge portion, said peripheral free edge portion of said central panel being positioned in overlapping relationship with and between said inner free edge portion and said parallel edge portion to prevent displacement of said central panel outwardly or inwardly of said rim portion during processing and handling, sealant means hermetically sealing said peripheral edge portion of said central panel with respect to said rim portion, and means associated with said central panel for enabling said central panel to be deformed to disengage it from its overlapping relationship with said rim portion to remove said central panel from said rim portion.

The advantage of severing the central panel from the rim portion is that the severed free edges of the central panel and the rim portion can be formed so as to be substantially burr-free or blunt thereby reducing the likelyhood of sharp edges capable of cutting the user, as may be found in scored ends of the full- open type.

Since the central panel is in overlapping relationship with the rim portion, the closure is able to withstand the high pressures to which canned foods are normally subjected during the cooking/sterilizing processes which are commonly used in the canned food industry.

In a preferred form of the invention described in greater detail below, the second oppositely directed fold is positioned in underlying relationship with said inner free edge portion and said peripheral free edge portion of said central panel is positioned in overlapping and underlying relationship with said inner free edge portion and in overlapping overlying relationship with said parallel edge portion. The advantage of this construction is that the free edge of the parallel edge portion can be hidden under the inner free edge portion and the sealant means is applied to the hidden inner face of the container member. Brief Description of the Drawings;

In order that the invention may be more readily understood, a presently preferred embodiment of the invention will now be described with reference to the accompanying drawings in which:.

Figure 1 is a plan view of a can end embodying the invention;

Figure 2 is a fragmentary sectional elevation of the can end taken along the line 2-2 in Fig. 1;

Figure 3 is an enlarged fragmentary sectional elevation of the closure formations shown in Fig. 2;

Figure 4 illustrates one method of opening the can end of Figs. 1 to 3.

Figures 5A to 5G illustrate the steps involved in one method of forming the can end embodying the invention, and a fragmentary sectional elevation of an alternative closure construction embodying the invention. Description of Preferred Embodiments:

Referring firstly to Figures 1 and 2 of the drawings, the can end 1 embodying the invention comprises a rim portion 2 having an inwardly directed or inner free edge portion 3 and a central panel 4 having a peripheral free edge portion 5, which has been fully severed from the rim portion 2, disposed in overlapping and underlying relationship with the free edge portion 3 of the rim portion 2.

The inner free edge portion 3 of the inner portion 2 is defined by a first underlying folded portion F_t, and a second spaced parallel folded portion F₂ is formed in underlying relationship with the first folded portion F_t and terminates in an edge E, positioned outwardly of the edge portion 3, to define a continuous groove G within which the peripheral free edge portion 5 of the central panel 4 is received.

In a particularly preferred form of the invention, the peripheral free edge portion 5 of the central panel 4 is formed with pairs of oppositely directed small dimples 6, 7 spaced equidistantly around the periphery of the free edge portion 5, as shown most clearly in Figure 1 of the drawings. As will be evident from Figures 2 and 3 of the drawings, the dimples 6, 7 cause the peripheral free edge portion 5 of the central panel 4 to be positioned substantially centrally between the folded portions Fl and F2. In this way, the sealant material 8 which is applied to the overlapping regions of the panel 4 and rim portion 2 is able to penetrate the region between the peripheral free edge portion 5 and at least the folded portion F2 to ensure that a proper hermetic seal is formed (see Fig. 3) .

To further ensure that a proper volume of sealant 8 is retained in the overlapping regions, the central panel 4 is formed with a continuous downwardly extending rib 9 which creates a barrier or reservoir which prevents movement of the sealant 8 towards the centre of the central panel 4 when the sealant is applied to the end 1 by any suitable method, such as that described in further detail below.

The central panel 4 is formed with a push-in easy opening closure C comprising a downwardly dished closure tab 10 which is fully severed from the panel 4 along line 11 to leave a hinge portion 12, and having a free edge portion 14 disposed in overlapping and underlying relationship with an edge portion 15 surrounding the opening 16 created by the severing operating. The closure C is formed, at free edge portion 14 of the closure tab 10, with spaced latch means 17 which frictionally engage the edge 11 of the edge portion 15 to inhibit movement of the tab 10 inwardly of the panel 4 and/or to provide an indication of opening or tampering, as shown most clearly in the enlarged sectional elevation of Figure 3. A sealant material 18 is applied to the overlapping regions of the edge portions 14 and 15 to hermetically seal the closure C in the central panel 4.

The closure tab 10 is dished in the manner shown and the opening 16 is shaped to receive the tip the bowl B of a spoon S in the manner shown in Figure 4 of the drawings. The shape of the opening 16 has also been designed to relieve points of weakness in the design of the closure C when the can end 1 is subjected to internal pressure, when fitted to a can, such as will occur when canned food products are processed for cooking and/or sterilizing.

During the opening operation, the bowl B of the spoon S is forced into the dished closure tab 10, forcing the tab 10 open past the latch means 17, breaking the sealant 18 and bending the tab 10 about the hinge 12, all as shown in Figure 4 of the drawings.

To ensure that the bowl B of the spoon S, or other similar implement, is maintained in the opening 16 during the levering operation necessary to remove the central panel 4 from the rim portion 2, the central panel has an inwardly directed abutment or dimple 19 formed in the central panel 4 centrally of the closure C opposite the hinge 12 and adjacent the edge portion 11 surrounding the opening 16 of the closure C. The dimple 19 is shaped to provide a vertical rear wall 20, and is dimensioned to be received in the tip portion of the bowl B, as shown in Fig. 4, with the wall 20 defining an adequate anchor point for the tip of the bowl B inserted in the opening 16 as it is levered agains^'t the rim 2, in the manner shown clearly in Figure 4 of the drawings, to deform the end panel 4 and remove the free edge portion 5 of the panel 4 from its underlying relationship with the free edge portion 3 of the rim portion 2. The anchor point provided by the dimple 19 operates to prevent the bowl B of the spoon S withdrawing from the opening 10 as the spoon S is levered against the rim 2.

It will be appreciated that without the dimple 19, the spoon may have a tendency to slide against the underside of the central panel 4 without adequately deforming the central panel 4 to facilitate removal of the panel from the rim. A similar tendency would be present in the case of the construction described in prior U.S. Patent 4003495, in which the rim of the bowl of the spoon engages the portion 32 which extends around the periphery of the closure 28 thereby creating extremely narrow frictional contact points between the bowl and the panel 16. In the present embodiment, the dimple 19 operates to inhibit relative sliding movement between the spoon S and the central panel 4 to ensure that the central panel 4 is properly deformed to allow its removal from the rim 2.

As described above, both the central panel 4 and the closure tab 10 are hermetically sealed with respect to the rim portion 2 and the edge portion 15 respectively by means of the application of sealant 12 and 18, such as a suitable plastisol, applied in any suitable manner known in the art, such as by an apparatus of the type described in our United States Patents Nos. 4102304, 4151314 and 4842469.

The above described closures are formed by suitable metal working operations, known in the art, for example as schematically illustrated in Figures 5A to 5G of the drawings. Figure 5A shows a typical can end shell on which the metal working operations necessary to form the above described closures are performed. In Figure 5B, the end shell is reformed to have a substantially vertical rim wall and the sealant retaining rib 9 is formed along with a central panel configuration which allows for expansion under internal pressure during canned food processing. It is also preferred that the dimples 6 and 7 are formed in the modified end shell, although they may alternatively be formed in a subsequent operation before the next step.

The next step is shown in Figure 5C and comprises shearing the central panel 4 from the rim portion 2. The left side of Figure 5C shows the position of the sheared elements at the bottom stroke of the dye operation, while the right side of Figure 5C shows the position at the upstroke of the die operation. As mentioned above, the shearing operation is performed so as to produce essentially burr-free or blunt free edges to thereby avoid the problems associated with sharp or jagged edges of the type produced when scored metal is severed. The previously substantially vertical side wall of the rim 2 is formed with an inwardly directed bend which constitutes the commencement of the fold F_t, the fold F₂ already having been partially formed by the bend in the panel at the bottom of the vertical side wall. If desired the side wall of the end shell may have a commencement of the first fold F₁ preformed by a rolling operation during or immediately after the formation of the curled edge in the edge portion 2, for example, as part of the commencement ring curling operation. This preforming operation assists the fold formation referred to above.

In Figure 5D, the size of the central panel is expanded by reducing the angle of the portion between the free edge portion 5 and the remainder of the central panel 4, and the folded portion Fl is further formed by collapsing the side wall of the rim 2 about the existing bends.

In Figure 5E, the double fold F,, F₂ has been flattened into its final form to capture the peripheral free edge portion 5, and in Figure 5F the closure tab 10 is severed along the line 11, the latch means 17 are formed in the free edge portion 16 of the tab 10 and the spoon engaging dimple 19 is formed. In the final working operation of Figure 5G, the tab 10 is coined to cause the free edge portion 14 to overlap and underly the free edge portion 15 and the latch means 17 to frictionally engage the edge of the opening 11. Sealant is then applied to the end at 8 and 18 and any necessary repair lacquer may also be applied to the exposed worked areas of the end 1.

While the embodiment shown in Figures 1 to 5 has the folded portions, F,, F₂ of the rim portion 2 located below the free edge portion 3, it may be acceptable in certain applications for the folded portions F,, F₂ to be disposed above the free edge portion 3, in the general manner shown schematically in Figure 6 of the drawings. In such an arrangement, the sealant shown protects the sheared edge of the rim portion 2 against corrosion, and while the free edge is exposed, its generally blunt configuration will prevent any serious risk of injury to the user.

The central panel 4 may be formed in any desired profile, such as shown in the drawings, to allow the central panel 4 to flex outwardly and inwardly during internal pressure changes caused by processing of the contents of the can. The profile of the central panel 4 may also be designed in a manner not shown to facilitate deformation of the central panel 4 along particular lines to facilitate easy removal of the central panel 4 from the rim portion 2.

Furthermore, the central panel 4 may be formed so that the panel is upwardly domed in its related state. In this way, loss of vacuum or more accurately, leakage of air into the can, may be visually detected.

While in the above described embodiments, the sealant S is applied externally after the closure has been formed, it will be appreciated that sealant material could be applied to portions of the rim 2 so that the free edge portion 5 of the central panel 4 is clamped between sealant covered surfaces to form the necessary hermetic seal or to form a further seal in addition to the sealant applied as described above.

While the closure 10 is dished in the embodiment shown, it can alternatively be essentially flat with an upstanding bend around the free edge portion 14 to assist in the formation of the latches 17 and to provide an engagement point for the spoon S during the opening operation.

Claims

CLAIMS:

1. A closure for a container member, such as a can end, comprising a panel formed with a rim portion and a central panel adapted for at least substantial removal from the rim portion, said central panel having a closure shaped to receive an opening implement, such as a spoon, and positioned adjacent said rim portion to allow the implement to engage the rim portion in use to lever the central panel from said rim portion, said central panel being formed with a downwardly extending abutment shaped and positioned to provide an anchor point for said implement to prevent said implement withdrawing from said closure during the levering operation.

2. The closure of claim 1, wherein said abutment comprises an inwardly directed dimple formed in said central panel centrally of and adjacent said closure in said central panel.

3. The closure of claim 2 wherein said dimple is preferably shaped to have a substantially vertical rear wall portion against which the tip of the bowl of a spoon engages as the bowl is levered against the rim portion to thereby provide said anchor point.

4. A closure of any preceding claim, wherein said central panel is at least substantially fully severed from said'rim portion and having a peripheral free edge portion, said rim portion having a first fold defining an inner free edge portion and a second oppositely directed fold defining an edge portion which extends in a spaced generally parallel relationship with said inner free edge portion, said peripheral free edge portion of said central panel being positioned in overlapping relationship with and between said inner free edge portion and said parallel edge portion to prevent displacement of said central panel outwardly or inwardly of said rim portion during processing and handling, sealant means hermetically sealing said peripheral edge portion of said central panel with respect to said rim portion, and means associated with said central panel for enabling said central panel to be deformed to disengage it from its overlapping relationship with said rim portion to remove said central panel from said rim portion.

5. The closure of claim 4, wherein said second oppositely directed fold as positioned in underlying relationship with said inner free edge portion and said peripheral free edge portion of said central panel is positioned in overlapping and underlying relationship with said inner free edge portion and in overlapping overlying relationship with said parallel edge portion.

6. The closure of claim 4 or 5, wherein the overlapping portions of said rim portion and said peripheral free edge portion are constructed to position said peripheral free edge portion to provide a gap between at least said parallel edge portion and said peripheral free edge portion to facilitate the penetration of sealant means into said gap.

7. The closure of claim 6, wherein said overlapping portions of said rim portion and said peripheral free edge portion are constructed to position said peripheral free edge portion substantially centrally between said inner free edge portion and said parallel edge portion.

8. The closure of any preceding claim, further comprising means associated with said central panel to retain the sealant means in the region of said overlapping portions of said rim portion and said peripheral free edge portion.

9. The closure of claim 8 wherein said sealant retaining means comprises a downwardly directed peripheral rib formed in said central panel inwardly of and adjacent said peripheral free edge portion.

10. The closure of claim 8, wherein said closure in said central panel comprises a push-in closure shaped to receive said opening implement under said central panel said push-in closure comprises a severed closure tab having a free edge portion in overlapping and underlying relationship with said central panel and an unsevered portion defining a hinge about which said tab is bent when- said_, push-in closure tab is opened, and sealant means hermetically sealing said closure tab with respect to said central panel.

11. The closure of claim 10, further comprising latch means formed in said free edge portion of said closure tab and frictionally engaging said central panel to inhibit unintended opening movement of said closure tab.