CN109515972B

CN109515972B - Tamper-evident metal pail and lid

Info

Publication number: CN109515972B
Application number: CN201811089032.8A
Authority: CN
Inventors: 克里斯托弗·保罗·拉姆齐; 斯蒂芬·罗比·耶茨
Original assignee: Crown Packaging Technology Inc
Current assignee: Crown Packaging Technology Inc
Priority date: 2017-09-19
Filing date: 2018-09-18
Publication date: 2021-05-04
Anticipated expiration: 2038-09-18
Also published as: GB2566554A; CN109515972A; GB201715105D0; GB2566554B; SG10201807670VA

Abstract

A metal lid for closing a pail, comprising: a central panel; a plurality of crimpable tabs surrounding the central panel; and a frangible feature that is associated with at least two of the tabs and is integrally formed with the tabs. The frangible feature is configured to break as a result of untwisting one of the at least two tabs. A container, comprising: a metal pail defining an opening and a metal lid, also disclosed, with tabs of the lid crimped onto the pail to close the opening.

Description

Tamper-evident metal pail and lid

Technical Field

The present invention relates to a tabbed lid for crimping onto a metal pail. More particularly, although not necessarily, the invention relates to a tabbed lid comprising tinplate.

Background

Metal containers for storing industrial products (e.g., paints, coatings, oils, lubricants, chemicals, etc.) including pails and lids are known in the art. Typical pail sizes include 5, 10, and 20 gallons. A 5 gallon pail can have a diameter of about 30cm and a height of about 47 cm. While such buckets are generally cylindrical, they may be other shapes, such as conical and rectangular. In some cases, the pails are tapered so that they can be nested before filling and after use. The pails and their covers may be made of tinplate or of other materials, such as steel or aluminium, and may be provided with handles for lifting.

As shown in fig. 1a, the known tinplate pail 1 comprises a cylindrical side wall 3 and a base 5, which base 5 is joined to the side wall 3. A curled edge 2 having a smooth surface is formed around the opening of the pail 1. Pail 1 can be sealed by lid 6 to form a container. The lid 6 is formed by a drawing operation from a blank of tinplate or aluminium, and the lid 6 has a central panel 7 from which depend a plurality of castellations or tabs 8, each castellation or tab 8 having an aperture 9 defined in a central region thereof.

As shown in fig. 1b and 1c, after filling the pail 1, the lid 6 is placed over the pail 1 opening and crimped over the crimped edge 2 and against the pail side wall 3 using a crimping tool, which may be manual or may form part of an automated production line process. In some applications, the underside of the lid is provided with a layer of sealing compound which forms a seal against the rim of the pail.

As mentioned above, each crenellated portion or tab 8 of the lid 6 is provided with an aperture 9. The openings 9 are generally circular in shape and typically have a diameter of about 8 mm. To open the sealed pail 1, the blade of a tool (such as a screwdriver) is inserted into the tab aperture 9 and used to pry the respective tab 8 away from the pail side wall 3 and rim 2. This process is repeated until substantially all of the tabs 8 have been "released" and the lid 6 can be lifted off the pail 1.

Typically, the pail and lid with castellations are undamaged during the crimping and opening process. As a result, the pail and lid can be reused or recycled once the original product has been used. However, used pails and their lids are sometimes refilled with counterfeit (i.e., counterfeit, low quality) products. The original lid may be re-crimped onto the pail and there is no way for a potential purchaser or consumer to discern that the product stored in the pail is not genuine.

Disclosure of Invention

According to a first aspect, there is provided a metal lid for closing a pail. The cover includes a central panel; a plurality of crimpable tabs surrounding the central panel, each tab defining an aperture therethrough for insertion of a lid removal tool therethrough; and a frangible feature associated with and integrally formed with at least two of the plurality of tabs. The frangible feature is configured to break as a result of untwisting one of the at least two tabs.

The cover may be a single piece of metal.

The breakable feature can be a bridge defined by a notch between the at least two tabs and a hole radially inward of the notch. The bridge may have a minimum radial dimension of between 0.8 and 1.5 mm.

The aperture for insertion of the cap removal tool may be a substantially circular aperture defined through the centre of the tab. The diameter of the opening may be at least 9 mm. The aperture may be spaced at least 5mm from an outer edge of the tab.

The plurality of tabs may include a plurality of pairs of tabs, with a breakable feature included between the tabs in each pair. The lid may include one or more crimpable tabs between each pair of tabs that are not joined to the frangible feature.

The circumferential extent of each tab joined to the frangible feature may be between 15 and 30 degrees. At least one other tab may be provided in the gap, the at least one other tab depending circumferentially from the center panel and defining a substantially circular aperture at a center thereof.

The metal cover may comprise one of tin-plated iron sheet, aluminum, and may have a thickness between 0.2 and 0.5 mm. The metal cover may include a layer of sealing compound extending circumferentially around the cover, radially inward of the tabs.

According to a second aspect, there is provided a container comprising a metal pail defining an opening; and the metal cover of the first aspect described above. The lid tab is crimped over the pail to close the opening.

According to yet another aspect, there is provided a metal lid for closing a pail. The cover includes a central panel; a plurality of crimpable tabs surrounding the central panel; and a frangible feature associated with and integrally formed with at least two of the plurality of tabs, the frangible feature configured to break as a result of crimping one of the at least two tabs open.

Drawings

FIG. 1a is a perspective view of a known metal pail and lid with castellations;

FIG. 1b is a perspective view of the upper portion of the pail of FIG. 1a with an uncrimped lid;

FIG. 1c is a perspective view of the pail of FIG. 1b with the lid crimped onto the pail;

FIG. 2 is a plan view of a metal blank used to form a crenellated cap in accordance with a first embodiment of the present invention, with a close-up view showing the tamper-evident features;

FIG. 3a is a perspective view of the crenellated cap formed from the blank of FIG. 2, with a close-up view showing the tamper-evident feature;

FIG. 3b is a side view of the cover of FIG. 3 a;

FIG. 3c is a cross-sectional view of the cap of FIG. 3 b;

FIG. 4a is a perspective view of a metal pail and an uncrimped lid according to a first embodiment;

FIG. 4b is a perspective view of a metal pail and crimped lid according to the first embodiment;

FIG. 5a is a perspective view of the pail and lid of FIG. 4b, showing removal of the lid;

FIG. 5b is a cross-sectional view of a portion of FIG. 5 a;

FIG. 6a is a plan view of a metal blank used to form a crenellated cap in accordance with a second embodiment of the present invention;

FIG. 6b is a perspective view of the blank of FIG. 6 a;

FIG. 7a is a schematic view of the metal blank of FIG. 6 a;

FIG. 7b is a schematic view of an enlarged portion of the metal blank of FIG. 6 a;

FIG. 7c is a schematic view of region A of FIG. 7a, including a tamper evident feature;

FIG. 7d is a schematic view of region B of FIG. 7 a;

FIG. 7e is a schematic view of region C of FIG. 7 a;

FIG. 8a is a perspective view of a metal pail and an uncrimped lid according to a second embodiment; and

fig. 8b is a perspective view of a metal pail and crimped lid according to a second embodiment.

Detailed Description

A metal pail and crenellated or tabbed lid according to a first embodiment will be described with reference to fig. 2-5 b. The lid includes a plurality of pairs of tabs, each pair including a tamper-evident frangible feature. A metal pail and crenellated or tabbed lid according to a second embodiment will be described with reference to fig. 6a to 8 b. The second cover includes a combination of pairs of tabs and conventional tabs.

FIG. 2 shows a metal blank 15a that can be drawn into a crenellated or tabbed lid 15b for sealing a metal pail. The blank 15a is formed (i.e., stamped or cut) from a single sheet of tinplate having a thickness of between about 0.2 and 0.5 mm. The metal blank 15a is generally circular in shape and defines a plurality of pairs of tabs or

castellations

17a, 17b about its circumference, each

tab

17a, 17b having a circular aperture 18 defined in its central region. Each circular aperture 18 is provided substantially centrally of each

tab

17a, 17b and has a diameter of at least 9mm and preferably about 10 mm.

Eight pairs of

tabs

17a, 17b are provided, including sixteen

individual tabs

17a, 17 b. However, fewer or additional pairs of

tabs

17a, 17b may be provided if desired. Each

tab

17a, 17b in a pair has a circumferential extent a of between 15 ° and 30 °. A gap 22 is defined between each pair of

tabs

17a, 17 b. In other words, the circumference of the blank 15a defines a pair of

tabs

17a, 17b, followed by a gap 22, followed by another pair of

tabs

17a, 17b, and so on.

As best shown in fig. 2, each pair of

tabs

17a, 17b includes a tamper-evident feature. The tamper evident frangible feature comprises a frangible bridge 19, which bridge 19 joins the two

tabs

17a, 17b together. A bridge 19 formed integrally with the

tabs

17a, 17b is defined by a notch 20 between the

tabs

17a, 17b and a bridge aperture 21 radially inward of the bridge 19. The angular extent of the opening of the notch 20 as far as it is may be about 90. Each bridge aperture 21 may be about 6.5mm in diameter.

The radial extent 23 of the bridge 19 (i.e. the radial distance between the notch 20 and the bridge hole 21) is adjusted to the dimensions of the pail 10 and its lid 15b, so that the metal blank 15a can be reliably manufactured from sheet metal material and drawn into the lid 15b without damaging the bridge 19. For a 300mm diameter cap 15b, a bridge 19 having a width or thickness of about 0.8 to 1.5mm is preferred. Surprisingly, even with such a narrow bridge, it has been found that it does not break during drawing and crimping. This is believed to be because the blank 15 a/lid 15b material is compressed in the radial direction during the drawing and crimping operation.

Fig. 3a to 3c show a lid 15b drawn from a blank 15 a. The lid 15b includes a concave central panel 16 surrounded by a stepped side wall 16a with a plurality of pairs of

tabs

17a, 17b depending from the side wall 16 a. As will be appreciated from the detail of fig. 3a, the tab aperture 18 and tamper-

evident features

19, 20, 21 are located below the edge of the lid 15b after the lid 15b has been drawn from the blank 15 a. Fig. 3b is a side view of the drawn-out lid 15b, and fig. 3c is a cross-sectional view through line AA' of fig. 3 a.

Fig. 4a and 4b show a lid 15b according to a first embodiment covering an opening defined by a metal pail 10. As previously discussed, the pail 10 is formed from a cylindrical side wall 12 and a base 13, and includes a curled edge 11 around its opening. The pail 10 is also provided with a handle 14. In fig. 4a, the lid 15b is not crimped. In fig. 4b, the lid 15b has been crimped onto the rim 11 of the pail 10 such that the opening of the pail 10 is sealed by the lid 15 b. The pail 10 and lid 15b together form a container.

The bridge apertures 21 and tab apertures 18 of the lid 15b are positioned so that the upper edge of each of the bridge apertures 21 and tab apertures 18 is just below the pail's curled edge 11 after being curled onto the pail 10. The gaps 22 (as described with reference to figure 2) between each pair of

tabs

17a, 17b ensure that the lid 15b can be crimped onto the pail rim 11 without twisting or irregular folding due to excess material, as excess material from the lid 15b can flow into the gaps 22 between the pairs of

tabs

17a, 17b as the diameter of the lid 15b is reduced during crimping. During crimping, the apertures 18 in the

tabs

17a, 17b become oval in shape, thereby also absorbing excess lid material.

Fig. 5a and 5b show the opening of the sealed pail 10 of fig. 4b using a bladed tool, in this case a screwdriver. The blade of the screwdriver is inserted into the tab aperture 18 of the first tab 17a of the pair of tabs and is used to pry the tab 17a away from the side wall 12 of the pail 10. During this process, the bridge 19 between the tab 17a, into which the blade has been inserted, and the second tab 17b of the tab pair breaks. In other words, the metal between the notch 20 and the bridge hole 21 is cut or sheared such that the notch 20 and the bridge hole 21 become continuous. After the bridge 19 breaks, the second tab 17b remains crimped against the pail side wall 12 until it is pried apart using a screwdriver. The width of each

tab

17a, 17b is adjusted so that its width is sufficient to form its own fold axis when crimped onto the pail 10, so that during removal of the lid 15b, the

pairs

17a, 17b do not behave like a single tab. To achieve this, the circumferential extent of each

tab

17a, 17b should be at least 15 ° from the bridging portion 19 to the centre of the gap 22 between the pair of

tabs

17a, 17 b.

To avoid the

tabs

17a, 17b themselves cracking when the cover 15b is removed, the distance between the lowest circumferential point of the tab aperture 18 (i.e. the point closest to the outer edge of the

tab

17a, 17 b) and the edge of the

tab

17a, 17b is preferably not less than 5 mm.

The breaking of the bridge 19 between the

tabs

17a, 17b of the tab pair provides a tamper-evident feature that allows the intended user or purchaser of the pail 10 to see that the pail 10 has been used. This reduces the likelihood that the pail 10 will be reused to store and sell counterfeit products. Further, the breaking of the bridge 19 creates a loud noise, making it apparent that the bridge 19 has broken when attempting to remove the lid 15b of the reused pail 10. It is important, however, that the breaking of the bridge 19 does not interfere with the reclosing and sealing of the pail 10, for example for storage after opening.

It will be appreciated that in order to remove the lid 15b completely from the pail 10, each bridge 19 must be broken and each

tab

17a, 17b must be pried away from the pail side wall 12 using a bladed tool until the lid 15b can be lifted away from the pail 10. With eight pairs of tamper

evident tabs

17a, 17b, there are eight bridges 19 to break. These bridges 19 can be broken in any order.

FIGS. 6a, 6b, and 7 a-7 e illustrate a crenellated or tabbed blank 25a according to a second embodiment. The lid 25b formed from this blank 25a may be used with the pail 10 of the first embodiment and can be crimped onto the pail 10 and removed from the pail 10 in substantially the same manner.

As shown in fig. 6a and 6b, the metal blank 25a from which the lid 25b is drawn is substantially circular in shape and includes a plurality of pairs of tabs or

castellations

27a, 27b which include a tamper-evident feature around its circumference, each

tab

27a, 27b defining a circular aperture 28. The tamper evident features include a notch 30, a bridge aperture 31 and a bridge 29 therebetween. Four pairs of tamper

evident tabs

27a, 27b are provided, including eight

individual tabs

27a, 27 b. However, fewer or additional pairs of tabs may be provided, if desired.

In addition to the pairs of tamper-

evident tabs

27a, 27b, the circumference of the blank 25a also includes a plurality of standard or conventional tabs 27 c. The conventional tabs 27c do not include any tamper evident bridges, notches or bridge holes, but each conventional tab 27c does define a tab opening 28 for use when removing the cover 25 b. The blank 25a includes eight conventional tabs 27c in addition to the four pairs of tamper-

evident tabs

27a, 27b, but the number may vary depending on the pail diameter.

As shown in fig. 6a and 6b, each pair of tamper-

evident tabs

27a, 27b is separated by two conventional tabs 27c, with a gap 32a between each conventional tab 27c and a gap 32b between the conventional tab 27c and the pair of tamper-

evident tabs

27a, 27 b. Each conventional tab 27c may have a circumferential extent β of about 22.5 °. Similarly, each tamper

evident tab

27a, 27b may have a circumferential extent epsilon of about 22.5 deg.. As mentioned above, a tamper-evident feature is included between each

tab

27a, 27b of the pair of tamper-

evident tabs

27a, 27 b.

Figures 7a to 7e show various configurations of notches 30 (zone a; figure 7C), gaps 32a between two consecutive conventional tabs 27C (zone B; figure 7 d), and gaps 32B between conventional tabs 27C and pairs of tamper-evident tabs 27a, 27B (zone C; figure 7 e). It will be appreciated that the circumferential extent of the gap 32a (shown by figure 7 d) between two conventional tabs 27c is less than the circumferential extent of the gap 32b (shown by figure 7 e) between the conventional tab 27c and the pair of tamper-

evident tabs

27a, 27 b. The gap 32a has a circumferential extent 34a of about 9.20mm at its narrowest point, while the gap 32b has a circumferential extent 34b of 11.32mm at its narrowest point. It will also be appreciated that the total depth 33a of the gap 32a is greater than the total depth of the gap 32 b. Gap 32a has an overall depth 33a of about 14.48mm, while gap 32b has an overall depth 33b of about 13.48 mm. The increased gap 32b between the conventional tab 27c and the pair of tamper-

evident tabs

27a, 27b absorbs excess material from the crimping operation, minimizing wrinkling of the lid material in the area between the

tabs

27a, 27b, 27 c.

Fig. 8a and 8b show a lid 25b according to a second embodiment covering an opening defined by a metal pail 10. The lid 25b is drawn from the blank 25a of fig. 6a, 6b and 7 a. In fig. 8a, the lid 25b is not crimped. In fig. 8b, the lid 25b has been crimped onto the rim of the pail 10 such that the opening of the pail 10 is sealed by the lid 25 b. As previously discussed, the lid 25b is crimped onto the pail 10 in the same manner as the lid 15b of the first embodiment. Lid 25b is removed from pail 10 in substantially the same manner as the lid of the first embodiment, by breaking bridge 29 and using a bladed tool to pry

tabs

27a, 27b, 27c away from pail 10.

The provision of pairs of tamper-

evident tabs

27a, 27b interspersed with conventional tabs 27c in the lid 25b of the second embodiment allows more space for excess material from the

tabs

27a, 27b, 27c to spread out during crimping, as discussed above. Fewer tamper

evident tabs

27a, 27b also allow pail 10 to open more quickly because fewer bridges 29 need to be broken.

Another benefit of the above-described tamper

evident caps

15b, 25b is that the security of the caps is improved in terms of pressure and drop performance. This can result in a reduction in the thickness of the lid material (lid thickness).

It will be appreciated by those skilled in the art that various modifications may be made to the above-described embodiments without departing from the scope of the present invention. For example, although the embodiments described herein include a circular pail and lid, the pail and lid can be non-circular, i.e. square, rectangular, tapered. Where the lid is rectangular, the tamper evident bridges may be formed between tabs on the corners of the lid.

In an alternative embodiment, all tabs on the lid are tamper evident tabs and each tab is joined to two adjacent tabs by a tamper evident bridge. In another alternative embodiment, the tamper evident tab may be opened by using a finger rather than a screwdriver. In this embodiment, the tab is not provided with an aperture for insertion of a removal tool, and the outer edge of the tab has a curled edge to improve safety.

Claims

1. A metal lid for closing a pail, the lid comprising:

a central panel;

a plurality of crimpable tabs surrounding said central panel, each tab defining a tab aperture therethrough for insertion of a lid removal tool therethrough; and

a frangible feature associated with and integrally formed with at least two of the plurality of tabs,

wherein the breakable feature is a bridge defined by a notch between the at least two tabs and a bridge aperture radially inward of the notch,

wherein the breakable feature associated with the at least two tabs is configured to break as a result of untwisting a first tab of the at least two tabs such that the notch and the bridge aperture become continuous,

wherein the untwisting is due to the insertion of the lid removal tool into the tab aperture of the first tab of the at least two tabs and for prying the first tab away from the side wall of the pail, and wherein a second tab of the at least two tabs is configured to remain curled against the side wall after the frangible feature is broken,

wherein each tab joined to the breakable feature has a circumferential extent between 15 degrees and 30 degrees.

2. The metal cover of claim 1, wherein the cover is a single piece of metal.

3. The metal cover according to claim 1 or claim 2, wherein the bridging portion has a minimum radial dimension of between 0.8mm and 1.5 mm.

4. The metal cover according to claim 1 or claim 2, wherein the aperture for insertion of the cover removal tool is a substantially circular aperture defined through the centre of the tab.

5. A metal cap according to claim 1 or claim 2, wherein the diameter of the aperture is at least 9 mm.

6. The metal cover according to claim 1 or claim 2, wherein the aperture is spaced from an outer edge of the tab by at least 5 mm.

7. The metal lid of claim 1, wherein the plurality of tabs comprises a plurality of pairs of tabs, the tabs in each pair comprising a frangible feature therebetween.

8. The metal lid of claim 7, comprising one or more crimpable tabs between respective pairs of tabs, the one or more crimpable tabs not being joined to the frangible feature.

9. A metal cover according to claim 1 or claim 2, wherein the cover comprises one of tinplate, aluminium.

10. A metal cover according to claim 1 or claim 2, having a thickness of between 0.2mm and 0.5 mm.

11. The metal cover according to claim 1 or claim 2, comprising a layer of sealing compound circumferentially surrounding the cover and extending radially inwardly of the tabs.

12. A container, comprising:

a metal pail defining an opening; and

a metal lid according to claim 1 or claim 2, wherein the tab of the lid is crimped over the pail to close the opening.