US3814279A - Lid for metal can and the like, particularly food can - Google Patents

Abstract

The disclosure relates to a lid for metal can or other packaging, the lid comprises in combination the following characteristics: slight sag at center; narrow cup bottom; high number of steps with each step ascending from the periphery of the lid toward its center; a bevel following each step and connected thereto by a relatively large radius.

Description

United States Patent [191 Rayzal 1 LID FOR METAL CAN AND THE LIKE,

PARTICULARLY FOOD CAN [75] Inventor: Jean Francois Rayzal, Paris, France [73] Assignee: Etablissements J.J. Carnaud &

Forges de Basseindre, Paris, France [22 Filed: Apr. 14, 1972 [21] App]. No.: 244,148

[30] Foreign Application Priority Data May 18, 1971 France i. 71.17897 [52] US. Cl 220/66, 215/41, 220/24, 220/67, ZZO/DIG. 19

[51] Int. Cl B65d 7/46, 365d 43/14 [58] Field of Search 220/24 R, 24 A, DIG. 19, 220/67, 66; 215/38 R, 38 B, 39, 40, 41

[56] References Cited UNITED STATES PATENTS Brusienski .1 220/24 1 June 4, 1974 10/1963 Creegan 99/152 3,160,302 12/1964 Chaplin 3,400,853 9/1968 Jacobsen 220/66 Primary ExaminerWil1iam 1. Price Assistant Examiner-Joseph M. Moy

Attorney, Agent, or FirmDiller, Brown, Ramik & Wight i V v M [5 7] ABSTRACT The disclosure relates to a lid for metal can or other packaging, the lid comprises in combination the following characteristics: slight sag at center; narrow cup bottom; high number of steps with each step ascending from the periphery of the lid toward its center; a bevel following each step and connected thereto by a relatively large radius.

10 Claims, 4 Drawing Figures PATENTEDJUN 4 I974 PNE Karma -63 LID FOR METAL CAN AND THE LIKE, PARTICULARLY FOOD CAN The present invention relates in a general way to any packaging and more particularly to metal cans currently used for packaging foods.

BACKGROUND OF THE INVENTION These cans are generally cylindrical with a base that is circular or not, for example, oval or quadrangular.

Such a can is made up either of a tubular body closed at each end by a lid added most often by crimping, or of a body closed at one end by a lid made one piece with it, such as by die stamping, and at the other end by a lid added most often by crimping.

In a general way, these lids are, overall, concave in relation to the outside of the can.

These lids have to assume an important role at the time of sterilization heat treatment which the cans of food undergo for sterilization.

Actually, during this treatment, these lids have to be able to move elastically to take the variations of inside pressure due to modifications of temperature in the can; when the temperature rises, this internal pressure increases and causes such a deformation in the lids that their concave profile becomes convex; at the time of cooling, the drop in internal pressure in the can causes a suction whereby the two lids of such a can undergo a deformation in the direction opposite the previous one, and their convex profile becomes concave again.

It is desirable that this new concave profile resume exactly the initial concave profile.

Actually, if a permanent deformation appears, i.e., if the return of a lid to the initial position is poor or incomplete, the can with such a lid is suspectedof being contaminated by a potential buyer and for this reason is no longer saleable.

To avoid such a permanent deformation, it is desirable that the passage of such a lid from its initial concave profile to a convex profile and the return of this lid from the convex profile to the initial concave profile be done as gradually as possible so that the yield strength of the metal or alloy, or more generally, of the material of this lid, not be reached.

Now, in a general way, the lids of present cans resist for a certain time, during the heat sterilization process of the can, the increase of internal pressure so that they suddenly deform outward, taking-on a convex profile; it is commonly said that they pop.

Depending on certain parameters such as the nature of the constitutive material of the lid, the shape of its profile, its thickness, the level of the filling of the can, the rate of increase of the temperature during the sterilization process, it can happen that in the passage of the lid from its initial concave profile to a convex profile occurs under such conditions the yield strength of the constitutive material of this lid is reached or even exceeded.

This drawback which, as has been seen, results in an unavoidable rejection of the can, is all the more serious since in certain present sterilization installations, the food cans are passed through a flame which makes it possible rapidly to reach the necessary sterilization temperature and therefore promotes the retention of the organoleptic properties of the food products contained in these cans.

SUMMARY OF THE INVENTION The present invention has particularly for its object a lid for a metal can or other packaging, in particular for food cans, able to deform very gradually under the action of pressure variations inside the can during sterilization treatment.

The present invention further has for its object a can thus provided with such a lid, and particularly a metal can for food products.

The lid according to the invention results from numerous tests and studies made particularly on its profile.

It has been established that such a profile intervenes for a considerable part of the course of the evolution of the deformation of this lid.

It has also been found that the modifications of minimal appearance in the various characteristics of this profile involve modifications in the nature of this evolution, without it being possible to establish with certainty the relation of cause and effect, or the interreaction with the modifications made jointly with other characteristics of this profile.

Thus, the lid according to the invention results from various compromises made over along period, after very many tests, trials and errors relating to the modifcation of the various characteristics'of the profile of these cans.

Consequently. it is particularly difficult to give individually the characteristics of the lid according to the invention, this lid being, on the contrary, characterized by a combination of various elements.

To define these elements more easily, it will be assumed hereafter that the crimping edge or flange of the lid is, overall, horizontal, its plane then serving as the plane of reference, and there will be taken as the dimension of reference the nominal diameter of the wall approximately vertical, usually consecutive to this crimping edge or flange, known as a cup or chuck wall, this nominal diameter actually corresponding to the diameter of the mandrel or chuck necessary for crimping or seaming of this lid.

These definitions having been given, a lid for a metal can according to the invention is of the type comprising from the periphery to the center, a crimping edge or flange more or less bent for lap jointing, assumed hereafter to be, overall, horizontal, a fairly vertical wall known as the cup or chuck wall, of diameter D, a fairly horizontal area, known as the cup bottom or end wall, a projecting flexibility ring, a succession of steps each followed by an intermediate bevel between-two connecting fillets, and a central zone called the rosette, not having any local deformation, and is characterized by the combination of the following elements:

a. the sag at the center, i.e., the vertical distance between the horizontal plane of the crimping edge and the center of the rosette is less than 0.06 D and preferably close to 0.05 D;

b. the width of the cup bottom, between the connecting fillets and parallel to the horizontal plane of the crimping edge is less than 0.036 D;

c. the number of steps is at least equal to n= D/SO D being expressed in millimeters, and n rounded off to the nearest unit, and preferably this number n is at least equal to [(D/SO) l];

d. each step ascends, from the periphery toward the center;

e. the radius of at least some of the connecting fillets associated with bevels is at least close to 0.0l D and preferably at least close to 0.02 D.

Further, the central rosette of the lid according to the invention is preferably fairly plane.

The characteristics of the lid according to the invention, set forth above, will be brought out better if it is made clear that this lid in its entirety is less curved than lids known so far, whose sag at the center is most often at least equal to 0.07 times the diameter of their cup, since its cup bottom has a width fairly less than the cup bottom of usual lids, since its number of steps is greater, most often by a unit, than the number of steps of the usual lids with equal diameter, since in the usual lids the steps always descend from their periphery to the center, and since in the usual lids the connecting fillets of the bevels have radii at least equal to 0.01 times the diameter of their cups.

For the reasons given above, it is difficult to determine the characteristic or characteristics of the lid according to theinvention which have the preponderant effectin the production of the result obtained.

However, the reversal of the slope of the steps in relation to the prior technique proves particularly favorable, and in this regard, the invention further has for its object a lid of the type mentioned above, characterized in that each of the steps rises from the periphery toward the center.

Regardless of the individual result of the various characteristics set forth above, experience shows that their combination leads to a lid capable of a very gradual deformation under the action of the internal pressure of the can equipped with the lid, during sterilization treatment.

In a word, the lid according to the invention does not pop suddenly during this sterilization process, as comparable lids known so far.

In particular, as the temperature of the sterilization process rises, the lid according to the invention very gradually deforms, which advantageously leads to a gradual increase of the internal volume of the can equipped with the lid.

Then as soon as the cooling of the can begins and as its temperature, and therefore its internal pressure, diminishes, the lid according to the invention gradually returns to its initial concave configuration.

The characteristics of the lid according to the invention and its advantages will come out better from the following description, with reference to the accompanying drawings, in which:

FIG. 1 is a partial perspective view of a food can to which the invention is applied;

FIG. 2 is a partial view in axial section of this can, considered as equipped with a known type lid;

FIG. 3 is an enlarged sectional view of the partial lid of FIG. 2 before its crimping on such a can;

FIG. 4 is a half view in axial section on the same scale as FIG. 3 of a lid according to the invention.

Referring now to the drawing, in FIG. 1 there is illustrated a metal can of the type comprising a body 10 on which a conventional lid 11 is added by crimping or seaming.

As can better be seen in FIG. 2, the conventional lid 11 has, overall, a concave profile in relation to the outside, as indicated by solid lines, and at the time of the process of sterilization of the can, it is supposed to be able, on the one hand, temporarily to take a convex 4, profile,as indicated by broken lines in FIG. 2, and on the other hand, come back to its initial concave profile.

The lid is illustrated in greater detail in FIG. 3 wherein, on an enlarged scale, a half view in axial section of the lid 11 before crimping is shown.

In a standard way, such a lid 11 comprises successively, from its periphery to its center:

' a. a crimping edge or flange 12, more or less bent for lap jointing or seaming. To faciliate the present description, it will be assumed hereafter that this crimping edge or flange I2, overall, is fairly horizontal, and the horizontal plane P of this edge will be taken as the plane of reference;

b. a fairly vertical wall 13, called the cup or chuck wall;

c. a fairly horizontal area 14, called the cup bottom;

d. flex facilitating ring 15, which is convex and therefore projects externally;

e. a limited number of steps 16, each of which descends from their periphery toward the center, each step being followed by a bevel 17 to which it is connected by a connecting fillet;

f. a central zone or rosette 18 which has no local deformation and overall presents a certain concave curve.

To facilitate the present description, the cup or chuck wall 13 will be defined by the tangent to its connecting fillet 13a with cup bottom 14, anddiameter D of this cup thus defined will be takenas the base dimension; also width L of the cup bottom 14 will be defined by the distance separating the tangents to the connecting fillets 13a and 14a which connect it, one to cup 13,

and'the other to ring 15, parallel to plane of reference P It is advisable for the explanation to make clear that in lids known so far:

I. sag F at the center of the lid, i.e., the distance separating horizontal plane P of crimping edge 12 from the center of central rosette 18 is most often equal to at least 0.07 D;

2. width L of the cup bottom 14 is at least equal to 3. number n of steps 16 is close to D/50, D being expressed in millimeters;

4. each step 16 descends from its periphery toward the lid center, i.e., its slope p in relation to a plane parallel to plane of reference P is negative.

In comparison with these arrangements, the lid according to the invention as illustrated in FIG. 4, and generally identified by the numeral 20 but with the components thereof identified by the same reference numerals as like components of the lid 11, comprises the following characteristics:

1. its sag F at the center is less than 0.06 D and is preferably on the order of 0.05 D; 2. width L of its cup bottom 14 is less than 0.036 D;

3. the number of its steps 16 is at least equal -to n=D/50, D being expressed in millimeters and n rounded off to the nearest unit, and preferably this number n is at least equal to [(D/50) I]. Thus, for example, and as shown, for the same diameter D of mm, the number of steps 16 is two in the standard lid 11 and three in the lid 20 according to the invention;

4. each step 16 ascends from the periphery of the lid 20 toward its center, i.e.. its slope p in relation to a plane parallel to plane of reference P is positive;

5. the radius of at least some of the connecting fillets connecting a bevel 17 either to adjacent steps 16 or to the central rosette 18, is at least on the order of 0.015 D and preferably at least on the order of 0.02 D;

6. the central rosette 18 is fairly flat.

To illustrate the invention more completely, there will be given below a numerical example of lid application intended for AFNOR l/ 1 cans:

diameter before any crimping close to 111 mm nominal diameter of cup close to 99 mm width of cup bottom close to 3.6 mm number of steps 3 slope of steps positive, between 0.05% and 0.20% depending on steps between I and 2 mm, inclusive, depending on the fillets.

radii of connecting fillets of bevels It is understood that this numerical example is in no way limiting of the invention and that the values which are given here can vary in a broad degree.

As experience has shown, the lid according to the invention presents a great flexibility and is actually capable of a gradual deformation when it is subjected to variations of internal pressure of the can to which it is attached.

This increase of flexibility can be characterized by the variations of volume of this can depending on its internal pressure.

By way of example the following table gives the increases of volume V1, V2 oftwo cans AFNOR l/l B,B' at different internal pressures P l, P 2, can B being equipped with the usual lid and can B with a lid 30 according to the invention, and all other conditions being equal, particularly the thickness of the lids considered and the nature of their constitutive material.

For Pl 0.6 kg/cm For P2 LX kg/cm Vl/VZ VI V2 B 55 cc X5 cc 1.54 B 72 cc 2.l2

claims.

I claim:

1. A new article of manufacture comprising a lid for attachment to a metal can and the like, particularly for food can, said lid in its free state comprising, in order from the periphery of the lid toward the center of the lid, a crimping edge configurated for lap jointing and generally lying in a horizontal plane, a generally vertical cup wall of diameter D, a generally horizontal cup bottom, a projecting flex facilitating ring, a succession of steps each followed by an intermediate bevel between two connecting fillets, and a central rosette generally free of local deformation, said lid being characterized in that said central rosette lies below said generally horizontal cup bottom and each step ascends from the periphery toward the center.

2. A lid according to claim 1, characterized in that the central rosette is generally planar.

3. A can, particularly a metal can for foods, provided with at least one lid according to claim 1.

4. The lid of claim 1 with said lid being characterized by the combination of the following relationships:

21. the sag at the center, i.e., the vertical distance between the horizontal plane of the crimping edge and the center of the rosette is less than 0.06 D;

b. the width of the cup bottom, between connecting fillets and parallel to the horizontal plane of the crimping edge is less than 0.036 D;

c. the number of steps is at least equal to n=D/50, D being expressed in millimeters, and n rounded off to the nearest unit;

d. the radius of at least some of the connecting fillets associated with the bevels is at least on the order of 0.015 D.

5. The lid of claim 4 wherein said sag at the center is on the order of 0.05 D.

6. The lid of claim 4 wherein said number of steps is at least [(D/50) l].

7. The lid of claim 4 wherein said radius of said connecting fillets associated with said bevels is at least on the order of 0.02 D.

8. The lid of claim 5 wherein said number of steps is at least [(D/50) l].

9. The lid of claim 8 wherein said radius of said connecting fillets associated with said bevels is at least on the order of 0.02 D.

l0. The lid of claim 6 wherein said radius of said connecting fillets associated with said bevels is at least on the order of 0.05 D.

O UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT N0. 3,814,279

DATED 1 June 4, 1974 tNVENTOR(S) I Jean Francois Rayzal It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

. Column 5, line 18, change "0.05% and 0.20% de-" to read 05% and 20% de- O Signed and Scaled this mu Day Of Aprill979 [SEAL] L Anm:

Q RUTH C MASON DONALD W. BANNER Amm'lg Omar Commissioner 01PM: and Trademark:

Claims (10)

1. A new article of manufacture comprising a lid for attachment to a metal can and the like, particularly for food can, said lid in its free state comprising, in order from the periphery of the lid toward the center of the lid, a crimping edge configurated for lap jointing and generally lying in a horizontal plane, a generally vertical cup wall of diameter D, a generally horizontal cup bottom, a projecting flex facilitating ring, a succession of steps each followed by an intermediate bevel between two connecting fillets, and a central rosette generally free of local deformation, said lid being characterized in that said central rosette lies below said generally horizontal cup bottom and each step ascends from the periphery toward the center.

2. A lid according to claim 1, characterized in that the central rosette is generally planar.

3. A can, particularly a metal can for foods, provided with at least one lid according to claim 1.

4. The lid of claim 1 with said lid being characterized by the combination of the following relationships: a. the sag at the center, i.e., the vertical distance between the horizontal plane of the crimping edge and the center of the rosette is less than 0.06 D; b. the width of the cup bottom, between connecting fillets and parallel to the horizontal plane of the crimping edge is less than 0.036 D; c. the number of steps is at least equal to n D/50, D being expressed in millimeters, and n rounded off to the nearest unit; d. the radius of at least some of the connecting fillets associated with the bevels is at least on the order of 0.015 D.

5. The lid of claim 4 wherein said sag at the center is on the order of 0.05 D.

6. The lid of claim 4 wherein said number of steps is at least ((D/50) + 1).

7. The lid of claim 4 wherein said radius of said connecting fillets associated with said bevels is at least on the order of 0.02 D.

8. The lid of claim 5 wherein said number of steps is at least ((D/50) + 1).

9. The lid of claim 8 wherein said radius of said connecting fillets associated with said bevels is at least on the order of 0.02 D.

10. The lid of claim 6 wherein said radius of said connecting fillets associated with said bevels is at least on the order of 0.05 D.

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