GB2125761A - Tear-open end closures for beverage cans - Google Patents

Abstract

A tear-open end closure, which may be made from sheet steel, for a beverage can has a substantially circular tear-open portion defined by a serrated line (9), a tear-tab (4) being mounted on the portion by means of rivet (3) which has a maximum diameter greater than the maximum diameter of the tear-open portion, and which covers a mounting lug (7) of the tab (4), whereby, inter alia, protection against injury by exposed edges is provided when the can has been opened. A cross-piece (11) may retain the tab (4) and portion on the closure after opening, and thus allow reclosure to exclude dust. <IMAGE>

Description

SPECIFICATION A tear-open cover for beverage cans The present invention relates to a tear-open lid or cover for cans. More particularly, the lid or cover of the present invention is generally made of sheet metal and is usually used for covering cans of, particularly, beverages. Such a cover includes a tear-open portion which is defined by a serrated line, a lever-like piercing tab which is mounted on the tear-open region by means of a rivet and which lies horizontally on the sheet metal cover, the tab being generally made from sheet metal and the mounting location of the tab being provided on a bendable lug.

The present invention relates, therefore, to a tear-open cover wherein the dimensions of the tear-open region are small compared with the overall dimensions of the cover, so that the tearopen region serves, in practice, to expose an aperture through which the liquid contents of the can may be poured. Tear-open covers of this general type are known from, for example, German Auslegeschrift No. 2623704. In such known cover arrangement, the tear-open region is in the form of a small, annular disc which is curved in a cup-shaped manner and is completely defined by a serration line or a line of weakness. A sheet metal gripping member in the form of a tab is centrally mounted on the disc-shaped tear-open portion by means of a small rivet formed from the sheet metal of the tear-open portion.Such tab gripping member is in the form of a ring and comprises an inwardly protruding mounting lug provided with an aperture, the lug being threaded onto the rivet. The tab gripping member protrudes beyond the tear-open portion on all sides and is so constructed that a relatively high pressure exerted approximately centrally thereon causes the disc-shaped tear-open portion to buckle and the connection between it and the sheet metal cover to be severed and, while simultaneously bending the mounting lug, the discshaped tear-open portion becomes disposed beneath the underside of the cover.In order to expose the pierced aperture, the unit comprising the tab gripping member and the tear-open portion may be laterally displaced parallei to the plane of the cover, so that the tab gripping member slips over the upper surface of the cover, and the tear-open portion slips beneath the underside thereof.

This arrangement is relatively complex and requires numerous components; hence, it is expensive to produce. The arrangement is not particularly easy to use. Moreover, such an arrangement is not suitable for covers made of sheet steel because the weakened connection between the tear-open portion and the sheet metal cover cannot be ruptured by mere finger pressure.

However, numerous covers are also known wherein the tab gripping member is connected to the tear-open portion and is so adapted that, if the tab gripping member is raised and a portion of the tear-open region is bent-down into the interior of the container, the serrated line or line of weakness is initially pierced at one location, whereupon a pulling operation causes the tear-open portion to shear outwardly along the remaining portion of these rrated line and to pivot beyond the external surface of the sheet metal cover.

In both of these known arrangements the tab gripping member is non-detachably connected to the tear-open portion, whilst the tear-open portion is directly or indirectly connected to the tear-open cover, so that, once the can has been opened, all of the component parts remain connected to one another. This is desirable both for environmental reasons and for prevention of injury to the user.

In the case of tear-off portions which open outwardly and are permanently disposed on the upper surface of the cover, there is a danger of the person opening the can being injured by the exposed edges of the pouring aperture or of the tear-open portion. It is also relatively easy, in such an arrangement, to pierce the tear-open portion prematurely and undesirably by inadvertently applying pressure onto the protruding rivet. In addition, considerable difficulties arise when forming the rivet from the sheet metal cover due to its small diameter. Because of the small size of the rivet and its connection, there is often a danger of the tab gripping member becoming accidentally detached from the tear-open portion.

These disadvantages are more pronounced if the cover is made from sheet steel. This is because, firstly, the forces which need to be applied to bring about the piercing and tearing-open are greater and, second, the formation of the rivet and the carrying out of the mounting operation are considerably more difficult than if softer and/or more ductile materials are used.

The present invention seeks to provide a tear-open cover of the general type described hereinbefore but in which the above-mentioned disadvantages are obviated or at least minimized.

According to the present invention, there is provided a tear-open cover for cans intended to be filled with liquids, such as drinks or beverages, the cover including a tear-open portion which is defined by a serrated line, a lever-like tear-open tab being mounted on the tear-open portion by means of a rivet and lying horizontally on the sheet metal cover in the closed state of the cover, the mounting for the tab being provided on a bendable lug, wherein the mounting rivet has a maximum diameter greater than the maximum diameter of the tear-open portion.

The large dimensions of such a rivet, compared with the dimensions of a conventionally used pouring aperture result in the arrangement being substantially more advantageously deformable, so that the cover of the present invention can also be made from sheet metals which are difficult to deform, such as sheet steels, and even doubly-reduced sheet metals (DR sheet metals). In conjunction with the correspondingly large mounting lug, the large rivet diameter provides a substantially more positive connection between the mounting lug and the body of the tab gripping member, so that the danger of the tab gripping member being accidentally torn from the mounting lug is considerably reduced. When the can is sealed, the rivet head, which is larger than the tear-open region, reliably absorbs external stresses or forces without causing a rupture of the serrated line.Such forces or stresses are transmitted directly, in the present invention, to the sheet metal cover surrounding the tear-open region, so that, even relatively strong stresses or forces can be absorbed without causing accidental piercing, and thus opening, of the can.

When the can has been opened, the outer periphery of the rivet head, which is formed by a rounded-off bent edge, protrudes beyond the torn edge of the tear-off region which is integrally connected to the rivet. This provides more effective protection against contact and injury. In addition, the entire tear-open portion is considerably reinforced by the rivet head protruding beyond such region, so that the tear-open portion also retains its disc-like shape after the tearing operation. This provides the advantage of a bending-back facility, whereby the pouring aperture can be re-sealed. This considerably reduces the chances of dirt and insects entering the can through the opened region.

Preferably, the bendable lug overlaps the tearopen portion on all sides.

Advantageously, the rivet head overlaps the bendable lug on all sides, with the exception of the connection region between the lug and the tab member. A stepped overlapping arrangement is therefore produced, the tear-open portion itself having the smallest diameter and the rivet head having the largest diameter. In such a case, it is advantageous if all of the components have a substantially circular shape and are concentric with one another.

The relatively large size of the rivet also permits the rivet to be formed from the sheet metal cover without excessively straining layers of lacquer which have previously been applied thereto thus considerably reducing the chances of the layers of lacquer becoming damaged by the deformation.

Conventional means may also be provided to give protection against contact with the torn edge surrounding the pouring aperture; for example, foil-like layers of plastics material may be provided on the underside of the cover, such layers being drawn or stretched over the torn edge during the tearing operation.

The annular tab member desirably concentrically surrounds the large rivet head and has a slight, radial clearance therefrom. Its abutment or support edge required for the piercing or opening operation is disposed externally of the tear-open portion. The initial piercing forces applied during the raising of the tab gripping member are transmitted positively via the large rivet head, to the regions of the serration line located adjacent the abutment edge. In such a case, a particularly advantageous leverage system is produced, so that only relatively small piercing forces are needed.If it is desirable for the tear-open region to be permanently connected to the remaining part of the sheet metal cover through a cross-piece, the arrangement may be adapted so that this connecting cross-piece lies substantially diametrically opposite the connection region between the tab member and the mounting lug.

One embodiment of the present invention will be described more fully hereinafter, by way of example, with reference to the accompanying schematic drawings, in which: Figure lisa plan view showing fragmentary sectional details of a tear-open cover in accordance with the invention; Figure 2 is a vertical sectional view taken along the sectional line ll-ll of Figure 1; and Figures 3 to 5 are views similar to that of Figure 2 but showing the tear-open cover in its closed state, in a partially open state and a fully open state, respectively.

The cover of the present invention is particularly suitably made from sheet steel. It is chiefly intended to provide, when open, only a relatively small pouring aperture for discharging the liquid contents.

In the drawings, the cover surface 1 of the tear-open cover is shown. The edge region 20 of the cover is illustrated in Figures 3 to 5. In the cover surface, a substantially circular, disc-shaped tear-open region 19, best seen in Figure 4 is defined by an appropriate serrated line 9. The serration line may be endless so that, during the opening operation, the tear-open portion 19 is completely separated from the sheet metal cover. However, it is preferable for the tearopen portion 19 to remain connected to the sheet metal cover, even when the can is opened. For this purpose, the serrated line 9 is made discontinuous by the formation of a solid cross-piece 11 which permanently connects the tear-open region 19 to the sheet metal cover.

A mounting rivet 3 is provided in the sheet metal cover. The size of the rivet 3 is selected in dependence upon the diameter of the cover and the size of the exposable pouring aperture 22 but has a diameter D which is large compared with the diameters chosen for conventional mounting rivets formed from the sheet metal cover. The diameter D of the rivet head may vary between 1.5 and 3 cm and is preferably 2.5 cm. The rivet neck is correspondingly large. This provides advantageous deformation conditions in the sheet metal cover.

Although the pouring aperture 22 is to be exposed during the tearing-open operation and its internal diameter is comparable with known tear-open portions, the diameter "d" of the tear-open region 19 is smaller than the diameter D of the rivet head 3.

When the cover is in its closed state, the rivet head 3 thus extends beyond the serrated line 9 and, when the cover is open the rivet head 3 extends beyond the torn edge of the tear-open region 19.

Due to the large dimensions of the rivet head, compared with known arrangements, a correspondingly large mounting is provided for the mounting lug 7 of a gripper tab 4. This latter is, of course, mounted on the sheet metal cover by means of the rivet 3. The tab gripping member 4 has a substantially annular body portion 5 but has a substantially straight abutment edge or flat at the transitional region 6 extending to the mounting lug 7. Such abutment edge is strengthened or reinforced by beads or ribs 10. The diameter of the mounting lug 7, which is also substantially circular, is referenced "a" in Figure 2 and, in the preferred embodiment, is greater than the diameter "d" of the tear-open region 19 and smaller than the diameter D of the rivet head 3.

In Figure 3, the arrangement is illustrated in a simplified form and with the can in the closed state.

In order to open the can, the body portion 5 of the tab gripping member 4 is raised at the end remote from the abutment region 6, as is illustrated by the arrow 16. In such a case, the abutment edge 6 is supported on the sheet metal cover externaily of the tear-open portion 19. The raising of the tab gripping member into the position illustrated in Figure 4 causes bending to occur in the abutment region 6 between the mounting lug 7 and the tab gripping member 5. Together with the abutment edge and the opposite region of the tab gripping member 5, the bending line determines the leverage at which the force 16 becomes effective. It will be seen that extremely advantageous power ratios are produced because of the very long effective gripper arm "g" (Figure 3) and the small power arm "e".Despite the cover being made from sheet steel, the serration line 9 can thus be pierced by the application of relatively little force, as is shown in Figure 4. By pulling the tab gripping member 5 in the direction of the arrow 24, the mounting lug 7, together with the rivet 3 and the tear-open portion 19, is pulled upwardly and rearwardly, whereby the sheet metal cover bends along a line on the cross-piece 11. In such a case, the actual tear-open portion remains substantially horizontal.

By pulling in the direction indicated by the arrow 24 in Figure 4, the pouring aperture 22 is initially exposed. By then pulling in the direction indicated by the arrow 25 in Figure 5, the tear-open portion 19, together with the rivet head 3, is bent through 1800 about the cross-piece 11, and the tab gripping member 5 is bent through substantially 1 80" relative to the mounting lug 7. Accordingly, all of the components, when the can is opened, are disposed on the sheet metal cover one behind the other and on the other side of the pouring aperture 22 compared with their locations in the closed state. It is apparent that the torn edge of the tear-open portion 19 is completely covered, to prevent any contact therewith, by the overlapping thereof both by the mounting lug 7 and by the rivet head 3, so that any risk of injury is eliminated. Because the tear-open region 19 remains horizontal, the pouring aperture 22 can be covered by the pivoting back tear-open portion, so that the possibility of dirt or insects entering the can is largely eliminated.

To facilitate the gripping of the tab gripping member 5, such member 5 may be upwardly curved in a slightly bulging manner at the end remote from the abutment, as illustrated at 17 in Figure 2.

Alternatively, the sheet metal cover in this region may also be indented, as indicated in broken lines at 18 in Figure 2. Both of these measures serve to facilitate the sliding of the end of a finger beneath the tab gripping member 5 when it is lying horizontally on the sheet metal cover.

Claims (9)

1. A tear-open cover for cans intended to be filled with liquids, such as drinks or beverages, the cover including a tear-open portion which is defined by a serrated line, a lever-like tear-open tab being mounted on the tear-open portion by means of a rivet and lying horizontally on the sheet metal cover in the closed state of the cover, the mounting for the tab being provided on a bendable lug, wherein the mounting rivet has a maximum diameter greater than the maximum diameter of the tear-open portion.

2. A cover as claimed in claim 1 wherein the material of the cover is sheet steel.

3. A cover as claimed in claim 1 or 2 wherein the tab is made of sheet metal.

4. A tear-open cover as claimed in claim 1, 2 or 3 in which the bendable lug overlaps the tear-open portion on all sides.

5. A tear-open cover as claimed in any preceding claim, in which the rivet head overlaps the bendable lug on all sides, with the exception of the connection region between the lug and the tab member.

6. A tear-open cover as claimed in any preceding claim in which the tab gripping member comprises an annular portion which surrounds the rivet head and having a slight, radial clearance therefrom.

7. A tear-open cover as claimed in any preceding claim, in which the tear-open portion, the mounting lug, the rivet head and the tab member all have a substantially circular or annular shape.

8. A tear-open cover as claimed in any preceding claim, in which the tear-open region is permanently connected to the sheet metal cover by means of a cross-piece or web, which web lies diametrically opposite the connection region between the tab member and the mounting lug.

9. A tear-open cover constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.