WO2014124510A2

WO2014124510A2 - Improvement in a metallic lid for cans

Info

Publication number: WO2014124510A2
Application number: PCT/BR2014/000050
Authority: WO
Inventors: Antonio Carlos Teixeira ÀLVARES; Antonio Roberto Sene
Original assignee: Brasilata S/A Embalagens Metálicas
Priority date: 2013-02-18
Filing date: 2014-02-17
Publication date: 2014-08-21
Also published as: BR102013003708A2; UY35331A; AR094811A1; WO2014124510A3

Abstract

The lid (20) of the invention comprises, in a single piece of metal sheet, a bottom wall (21) incorporating, superiorly and peripherally, a side wall (22) to be frictionally seated and axially retained in the can (10). The bottom wall comprises a peripheral annular portion (23) adjacent to the side wall (22), a median portion (24) and an annular rib portion (25) having a cross section with the approximate form of an inverted "U" having the lateral legs thereof respectively incorporated to adjacent edges of the peripheral annular portion (23) and median portion (24) of the bottom wall (21). The peripheral annular portion (23) of the bottom wall (21) incorporates, in its median portion and in a single piece, at least one embossed circumferential rib (26), generally in the form of an inverted U, formed by a material that is plastically deformed from said peripheral annular portion (23).

Description

IMPROVEMENT IN A METALLIC LID FOR CANS

Field of the invention

The present invention refers to an improvement in a metallic lid of the type which presents a peripheral side wall provided with a free upper edge and designed to be frictionally seated and axially retained in the interior of a seat defined in an upper opening of a can, the lid being optionally provided, in its central region, with an inspection opening to receive an auxiliary lid generally in a transparent plastic material .

Prior art

Metallic lids of the type mentioned above are well known, being formed in a single piece of metal sheet and comprising a generally disk-shaped bottom wall, whose peripheral edge incorporates a side wall projecting upwardly, so as to be removably press fitted and axially retained inside a seat defined in an upper opening of a can. Said seat may be defined by a pending tubular projection which is superiorly incorporated to a median opening of the upper wall of a can with a circular or polygonal cross section.

Metallic lids of the type mentioned above are described and illustrated in patent documents US2,074,231, US3,347,408, BR-MU8002622-2 , BR-

Μϋ80026ΐ8-4 and also in patents BR-PI9408643-5 and BR- MU7S01221-2 and BR- PI0802598-3, the last three pertaining to the same applicant of the present patent application .

In these prior art constructions, the lid structure comprises only the bottom wall and a peripheral side wall, the axial retention of the lid in the seat, defined in the upper opening of the can, being usually achieved through engaging means provided in at least one of the parts of lid side wall and seat in the upper opening, in order to cooperate with the other of said parts.

In the construction of the type cited above, even when the bottom wall of the lid presents a drawn or raised median portion, as taught in the solution disclosed in patents BR-MU 7601221-2 and US3,347,4-8, the lid structure requires certain cares to be taken when closing forces are applied, which forces can irremediably damage said lid, impeding a tight and secure closure of the can to be obtained.

The structural deficiency mentioned above is due to the fact that said lid construction does not present the usual peripheral strength guaranteed in the metallic lids provided with a peripheral annular recess, generally having a cross section with a substantially trapezoidal and inverted form, to be frictionally seated in the interior of a recess with a complementary cross section which defines a seat incorporated to the annular upper wall of a can body, such as in the construction known for decades and which is disclosed and illustrated in patent US795,126, filed in 1904.

Aiming at increasing the structural strength of the known lids, which present only the bottom wall and a peripheral side wall formed to be seated and axially retained in an upper opening of the can, it was proposed the constructive solution, which is disclosed and claimed in the Brazilian patent application PI0405458-0 of the same applicant, according to which the bottom wall of the lid comprises a peripheral annular portion and a median portion which are interconnected by an annular rib portion having the approximate form of an inverted U. This previous construction provides the lid, which is formed in a determined metal sheet thickness, with an increased structural strength, overcoming the deficiency of these known lids, without requiring the metal sheet thickness to be increased. The provision of the annular rib portion in the bottom wall, as proposed in PI0405458-0, leads to a higher structural strength of the lid.

However, even incorporating the annular rib portion in the bottom wall of the lid, the structural strength necessary for an adequate and secure operational behavior of the lid still requires the metal sheet to have a certain minimum thickness.

Aiming at further increasing the structural resistance of the lids, the present applicant developed the solution object of the previous patent application BR- PI0802598-3, according to which the median portion of the bottom wall is formed with an annular panel and a central panel, which are circumferentially joined by an axial step portion, and with an outer peripheral edge of the annular panel is incorporated to the adjacent lateral walls of the inverted U-shaped annular rib portion, the axial step portion being formed by a material that is plastically deformed from the adjacent portions of the annular panel and central panel .

Although increasing the resistance of the median portion of the bottom wall of the lid, this prior solution BR- PI0802598-3 does not allow said increase in resistance to reach the peripheral annular portion of the bottom wall. of the lid. This is due to the fact that said peripheral annular portion defines the portion of the lid subjected to high flexing stresses upon the application of closing forces on the lid. Thus, even with the increase in the structural resistance of the median portion of the bottom wall of the lid, the latter still demands a certain minimum thickness of the metal sheet due to the stresses that said peripheral annular portion has to withstand, in order to prevent permanent plastic deformations during the closing operations of the lid.

Summary of the invention

As a function of the exposed above in relation to the prior art, the present invention has as one of its objects to provide an improved metallic lid of the type commented above, which is provided with the annular rib portion in the bottom wall and which has an additionally increased strength, allowing said lid to be constructed in metal sheet with a reduced thickness, thinner than the minimum presently used for this type of lid, said thickness reduction not reducing the structural strength of the lid to values lower than those expected or desired to allow closing and opening the lid by the usual proceedings, with no risks of producing unacceptable plastic deformations. This and other objects of the present invention are attained by providing a metallic lid of the type which has its bottom wall comprising a peripheral annular portion, adjacent to a side wall of the lid, a median portion, and an annular rib portion presenting its cross section with the approximate form of an inverted U, whose lateral legs are inferiorly and respectively incorporated to the adjacent edges of the peripheral annular portion and the median portion of the bottom wall .

According to the invention, the peripheral annular portion of the bottom wall incorporates, medianly and in a single piece, at least one embossed circumferential rib formed by a material which is plastically deformed from said peripheral annular portion .

In a preferred constructive form, the circumferential rib is continuous and has a U-shaped cross-section having rounded ends .

With the construction generically defined above, besides the fact that the medium portion and the peripheral annular portion of the bottom wall of the can are joined to each other by said annular rib portion, the peripheral annular portion now incorporates the circumferential rib, which defines an additional structural element incorporated to a region of the bottom wall of the lid subjected to high stresses during the closing and opening operations of the lid.

The provision of the circumferential rib in the peripheral annular portion, in addition to the provision of the annular rib portion, imparts to the lid a structural strength that is substantially greater than that achieved with the prior art constructions, allowing obtaining lids having adequate structural strength and formed in a metal sheet with a smaller thickness, that is, with less material consumption .

Furthermore, the construction of the improved lid object of the present invention can be made so that the median portion of the bottom wall presents an inspection opening defining a seat for seating and axially retaining an auxiliary lid in a transparent plastic material.

Brief Description of the Drawings

The invention will be described below, with reference to the enclosed drawings, given by way of example of possible constructions for the present lid and in which :

Figure 1 represents a partial diametrical sectional view of the upper region of a can, in whose discharge end opening is fitted a lid constructed according to one of the known prior art solutions;

Figure 2 represents a top plan view of a lid of the type illustrated in figure 1, but incorporating a circumferential rib in the peripheral annular portion, according to the invention;

Figure 3 represents a partial diametrical sectional view of the lid, when mounted in the discharge end opening of a can, said view taken according to line III-III in figure 2;

Figure 4 represents a top plan view of an alternative construction of the present improved lid; and

Figure 5 represents a partial diametrical sectional view of the lid when mounted in the discharge end opening of a can, said view taken according to line V- V in figure 4.

Description of the invention

As illustrated in the enclosed drawings, the lid of the present invention is applied to a can 10, which is graphically represented only by the upper portion of its side wall 11, to whose upper edge is affixed, usually by means of a double-seam 12, an outer peripheral edge of an annular upper wall 13 in whose median region is provided an opening 14 to whose edge is incorporated a pending tubular projection 15 which defines a seat "S" for seating the lid of the can.

In the prior art construction exemplified in figure 1 of the drawings and which is object of patent BR9408643-5 of the applicant of the present patent application, the pending tubular projection 15 is provided with a lower end portion which is bent inwardly of the opening 14, upwardly and against the pending tubular projection 15, so as to form a continuous tubular rib 16, which has a generally circular shape, as described in said prior art patent. However, it should be understood that the construction of the pending tubular projection 15 of the annular upper wall 13 of the can 10 may have different constructive arrangements, as illustrated and discussed in the prior art documents mentioned above, without said constructive modifications altering the constructive and functional objectives of the present invention.

As already previously mentioned, the lid 20 of the present invention is formed in a single piece of metal sheet, comprising a bottom wall 21 usually in the form of a flat disk and which superiorly and peripherally incorporates a side wall 22 provided with a free upper edge 22a and designed to be frictionally seated and axially retained inside the seat "S" defined by the pending tubular projection 15 of the opening 14 provided in the annular upper wall 13.

In the exemplary construction illustrated in the drawings, the lid 20 has its side wall 22 provided with a continuous peripheral recess 22b, inside which is sealingly fitted and axially retained the continuous tubular rib 16 of the pending tubular projection 15.

In the illustrated construction, both the continuous tubular rib 16 of the pending tubular projection 15 and the continuous peripheral recess 22b of the side wall 22 of the lid 20 present a contour which is at least partially circular and complementary, so that the mutual seating of said parts promotes not only the axial retention of the lid 20 in the opening 14 of the can 10, but also a sealing effect in this frictional seating region. It should be understood, however, that the continuous tubular rib 16 and the continuous peripheral recess 22b may present configurations other than that tubular circular illustrated in the drawings, as it can be observed in the prior art documents cited in the beginning of the present specification.

Still according to the embodiment illustrated in the drawings, the lid 20 has its free upper edge 22a preferably bent ^' outwardly, downwardly and against the side wall 22, so as to define a tubular upper rib 22c to be seated on the annular upper wall 13 of the can 10, in the region that surrounds the opening 14. Accordingly, it should be understood that the free upper edge 22a of the side wall 22 of the lid 20 may present different constructive forms, as illustrated in the prior art documents previously cited, without said modifications of form and arrangement of the upper region of the side wall 22 of the lid 20 altering the functional characteristics of the invention proposed herein.

The bottom wall 21 of the lid 20 comprises a peripheral annular portion 23 adjacent to the side wall 22, a median portion 24 and an annular rib portion 25 presenting a cross section with the approximate form of an inverted U, whose lateral legs are interiorly and respectively incorporated to adjacent edges of the peripheral annular portion 23 and median portion 24 of the bottom wall 21.

The annular rib portion 25 is stamped jointly with the remainder of the lid 20, in order to project preferably upwardly from both the peripheral annular portion 23 and the median portion 24 of the bottom wall 21, the annular rib portion 25 remaining spaced from said side wall 22 by an adequate distance for forming the lid and which, due to the metal sheet thickness, provides to the marginal region of the lid 20 the necessary structural strength to resist the compression forces to be applied over the lid 20, upon fitting the latter in the opening 14 of the can 10. Still according to the preferred embodiment, the median portion 24 of the bottom wall 21 is disposed in a higher plane in relation to a plane which contains the peripheral annular portion 23 of said bottom wall 21. This constructive arrangement allows the median portion 24 of the bottom wall 21 to operate jointly with the annular rib portion 25 to define seating means to place one lid over the other, upon stacking said lids in a lid feeding device in an automatic can closing machine, or to allow the lids 20 to be automatically fitted in respective annular upper walls 13, before they are double-seamed to the side wall 11 of the cans 10.

The annular rib portion 25 is further constructed and dimensioned in such a way as to be disposed inferiorly to a plane Ps containing the free upper edge 22a of the side wall 22 of the lid 20, this relative dimensioning of the lid parts being made as a function of the stacking characteristics cited above and discussed in PI0405458-0.

According to the invention, the peripheral annular portion 23 of the bottom wall 21 incorporates, in a single piece, at least one embossed circumferential rib 26, preferably continuous and having a cross section in the form of an inverted U with rounded ends, which is formed by the deformation of the metal sheet itself. Although not illustrated herein, the cross section of the embossed circumferential rib 26 may present the form of an inverted V, having a generally rounded vertex, also formed by deformation of the metal sheet itself.

The U profile of the circumferential rib 26 is preferably inverted so that the base leg 26a thereof faces the outside of the lid 20, with the lateral legs 26b thereof being respectively and inferiorly incorporated to the adjacent opposite regions 23a of the peripheral annular portion 23.

Although it is possible to form the circumferential rib 26 facing the inside of the lid 20, this constructive arrangement produces on the lid a generally undesirable lower projection, facing the interior of the can, which is destined to the storage of products.

In the illustrated embodiment it is provided a single circumferential rib 26 forming, in the peripheral annular portion 23, opposite regions 23a, with radial widths which are equal or approximately equal.

In order for the lid 20, provided with the circumferential rib 26, to be formed from a metal sheet blank having the same dimension of the one for producing the lid defined in figure 1, the circumferential rib 26 is formed by the plastically deformed material of the peripheral annular portion 23, without the need of increasing the contour of the blank in order to make possible the formation of the circumferential rib.

The height of the circumferential rib 26, that is, of the lateral legs 26b thereof, should be just enough in order to produce the desired effect of increasing the structural resistance of the lid 20, having preferably a value approximately equal to the thickness of the metal sheet used for forming the lid 20, in order that the material used for its formation is provided exclusively from the material that is plastically deformed, during the stamping operation of the lid, from the adjacent opposite regions 23a of the peripheral annular portion.

With the construction proposed by the invention, besides the median portion 24 and peripheral annular portion 23 of the bottom wall 21 being joined together by said annular rib portion 25, the peripheral annular portion 23 also incorporates the circumferential rib 26, which defines an additional structural element incorporated to a region of the bottom wall 21 of the lid 20 subjected to high stresses during the closing and opening operations of the can.

The provision of the circumferential rib 26 in the peripheral annular portion 23, additionally to the provision of the annular rib portion 25, provides the lid 20 with a substantially increased structural resistance. Said increase in resistance allows obtaining lids 20 having a suitable structural resistance, while formed in a metal sheet of reduced thickness, that is, with lower material consumption. For example, in the known 1 gallon cans, the reduction in the thickness of the metal sheet can be higher than 10%.

In the construction illustrated in figures 4 and 5, the median portion 24 of the lid 20 is provided with an inspection opening 27 radially spaced from the annular rib portion 25, defining a seat for seating and axially retaining a peripheral side wall 31 of an auxiliary lid 30 of transparent plastic material, said inspection opening 27 comprising a pending skirt 28 formed to incorporate an inner circumferential curl 29 to be fitted in a corresponding circumferential recess 33 provided in the peripheral side wall 31 of the auxiliary lid 30. The construction of the inspection opening 27 and of the auxiliary lid 30 can follow the same proceedings applied to the lid 20, maintaining the dimensions of the involved parts proportionally adequate to the smallest diameter of the auxiliary lid 30.

While only two constructive forms for the lid, jointly with a seat construction, have been illustrated herein, it should be understood that changes can be made in the form of the component parts, without departing from the constructive concept defined in the claims that accompany the present specification.

Claims

1. An improvement in a metallic lid for cans, said lid (20) comprising, in a single piece of metal sheet, a bottom wall (21) incorporating, superiorly and peripherally, a side wall (22) to be frictionally seated and axially retained in the can (10), and which comprises a peripheral annular portion (23) adjacent to the side wall (22), a median portion (24) and an annular rib portion (25) having a cross section in the approximate form of an inverted "U" with the lateral legs thereof being respectively and interiorly incorporated to the adjacent edges of the peripheral annular portion (23) and median portion (24) of the bottom wall (21), said improvement being characterized in that the peripheral annular portion (23) of the bottom wall (21) incorporates, medianly and in a single piece, at least one embossed circumferential rib (26) formed by a material that is plastically deformed from said peripheral annular portion (23).

2. The improvement, as set forth in claim 1, characterized in that the circumferential rib (26) is continuous and presents a U-shaped cross section having rounded ends.

3. The improvement, as set forth in claim 2, characterized in that the circumferential rib (26) has the cross section thereof in the approximate form of an inverted U, with the base leg (26a) thereof facing the outside of the lid (20) and with the lateral legs (26b) thereof being respectively and inferiorly incorporated to adjacent opposite regions (23a) of the peripheral annular portion (23) .

4. The improvement, as set forth in any of claims 2 or 3, characterized in that the peripheral annular portion (23) incorporates a single circumferential rib (26) forming, in the peripheral annular portion (23) , opposite regions (23a) with equal radial widths.

5. The improvement, as set forth in any of claims 2, 3 or 4, characterized in that the circumferential rib 26 has the material for its formation defined exclusively by a material that is plastically deformed from the adjacent opposite regions (23a) of the peripheral annular portion (23).

6. The improvement, as set forth in any of claims 1 to 5, characterized in that the annular rib portion (25) projects above the peripheral annular portion (23) and median portion (24) of the bottom wall (21) .

7. The improvement, as set forth in claim 6, characterized in that the median portion (24) of the bottom wall (21) is located in a plane higher in relation to a plane containing the peripheral annular portion (23) .

8. The improvement, as set forth in claim 7, characterized in that the annular rib portion (25) is located lower than a plane (Ps) containing a free upper edge (22a) of the side wall (22) of the lid (20) .

9. The improvement, as set forth in any of claims 1 to 8, characterized in that the median portion (24) of the bottom wall (21) is provided with an inspection opening (27) spaced from the annular rib portion (25), defining a seat for seating and axially retaining a peripheral side wall (31) of an auxiliary lid (30) of transparent plastic material, said inspection opening (27) comprising a pending skirt (28) formed to incorporate an inner circumferential curl (29) to be fitted in a circumferential recess (33) provided in the peripheral side wall (31) of the auxiliary lid (30) .