US2924369A

US2924369A - Metallic receptacles

Info

Publication number: US2924369A
Application number: US529058A
Authority: US
Inventors: Donald L Richter
Original assignee: Kaiser Aluminum and Chemical Corp
Current assignee: Kaiser Aluminum and Chemical Corp
Priority date: 1955-08-17
Filing date: 1955-08-17
Publication date: 1960-02-09
Anticipated expiration: 1977-02-09

Description

.F 1960 D. L. RICHTER 2,924,369

METALLIC RECEPTACLES Filed Aug. 17, 1955 INVENTOR DONALD L. RICHTER METALLIC RECEPTACLES Donald L. Richter, akland, Calif., assiguor to Kaiser Aluminum & Chemical Corporation, Oakland, Calif., a corporation of Delaware Application August 17, 19'55, Serial No. 529,058

7 Claims. (Cl. 229-35) This invention relates to receptacles formed of light, thin sheet metal. More specifically, the invention relates to the production of and the resultant article which may be fabricated from extremely thin sheet metal and particularly lightweight metals, such as aluminum foil. Specifically, the invention relates to the reinforcement of thin metal foils when the same are fabricated into containers.

'Thin metal foils, such as aluminum foil, have found wide-spread use inrecent years in the food container field. These foil containers may or may not be disposable in nature. The use of such containers is particularly prevalent throughout the baking industry wherein bakery products may be cooked, stored and oftentimes quick frozen for use by the householder at a subsequent date. Such containers generally take the form of a pie plate or similar article and the use specified is also extended to frozen foods, prepared foods, cakes, and the like which require the provision of a cheaply fabricated, readily disposable baking, storing or transporting receptacle. Because of the abuse and rough handling to which such containers are subjected, they must also be relatively strong and rigid.

- While the use heretofore of impregnated papers for such articles hasfound moderate success, the ready availability and advantages gained from the use of moisture impermeable metal foils, such as aluminum foil, which may be of varying thickness, has resulted in a general acceptance of said foil material for the purposes expressed. It will be appreciated that in the fabrication of such articles,'cost is a prime consideration. Accordingly, efforts have been, made toutilize extremely thin gauge'foil material to reduce the cost of the fabricated receptacles'thereby enabling wider and more varied uses ofsuchr'eceptacles.'

Assa result of this tendency toward use of a thinner gauge metal foil material, receptacles have been proportionately reduced instren'gth with the result that the use thereof-for the purposes expressed has not at all times proven satisfactory;

Accordingly, theinvention relates to an arrangement for -reinforcingreceptacles made of light gauge sheet metal byproviding suitablyconfigured stamped or deep embossed geometric' patterns in the lower surface or bottom thereo'f'.wl1 il'e-at the same time incorporating an improved rim'fstructure in the receptacle whereby the resultant -receptacle'will be sufficiently strong and capable of being easily fabricated of light, extremely thin gauge metal foil material. It is an object of this invention to provide a 'novel receptacle which is stronger and more rigid, and which resists bending or deformation.

It isa principal object of this invention to provide a novel receptacle formed of light metal of extremely thin gauge'mat'eriall- I'Still another object of the invention is to provide a uniquely reinforced receptacle wherein the reinforcement is;ineor'porated in'the article in-a novel fashion during formation of the article whereby even though made of 0 Ice Patented Feb. 9, i9

Q extremely thin gauge metal foil such as aluminum foil the resultant container will be exceptionally strong and rigid.

A further object of the invention is to produce a receptacle and a reinforcement of such a receptacle to permit formation of the same of extremely thin sheet material such that the resultant article will be comparative in strength to articles formed of material of considerably heavier gauges or thickness.

These and various other objects of the invention will become more apparent from an inspection of the drawings, wherein:

Figure 1 is a perspective view of an inverted, reinforced receptacle produced in accordance with the instant invention;

Figure 2 is a sectional view taken through the receptacle shown in Figure 1 and discloses the lip portion as well as the sidewall and bottom portions of the receptacle, the hypothetical conical projection of the lip and wall portions being indicated by dotted lines; and

Figure 3 is an enlarged partial sectional view through one of the reinforcing ribs of the receptacle when taken along the line 3-3 of Figure 1, illustrating clearly the preferred form which such reinforcing elements should take.

In referring to the drawings and the following specification it is to be appreciated that the advantageous features of the instant invention may be incorporated in a variety of receptacles and is not necessarily confined to the round receptacle specifically disclosed in Figure 1 of the drawing and described hereinafter. The advantages to be gained from the present invention, however, are attained with greatest particularity in an article of the type specifically referred to hereinafter.

As may be seen from an inspection of the drawings, the bottom surface of the receptacle disclosed is closed and is formed with suitably arranged stamped or deep embossed portions which serve to reinforce the comparatively large and generally unsupported extent of sheet material in such a manner that bending and deflection of the bottom portion of the receptacle will be prevented.

Similarly, the wall and rim or flange portions of the structure are so arranged as to provide additional reinforcement of the entire structure whereby not only the rim and wall portions, but the entire receptacle will be considerably stronger than those'heretofore known in the art and wherein the reinforcement is of such a kind and nature as to permit the use of extremely thin gauge materials, such as aluminum foil, in the fabrication of such receptacles.

Referring now in particular to Figure 1 it may be seen that the receptacle comprises a flanged portion 1 arranged in circumscribing annular relation to the major body portion of the receptacle formed integrally therewith. The major body portion of the receptacle comprises a sloping wall 2. This wall portion 2 terminates in a disclike closed bottom 3. The sloping wall portion 2 and the integrally formed flanged portion 1 are so constructed that each comprises what may be considered a frustoconical surface. The projections of these surfaces as indicated by the dotted lines in Figure 2, in effect, generate a pair of oppositely facing conical surfaces which intersect generally at the points C and D. It has been discovered that the benefits to be gained from the use of a peripheral flange on the wall portion 2 are enhanced to a considerable extent when the summation of the apex angles, A and B as shown in Figure 1, of the cones generatedby the two surfaces 1 and 2 approaches a sum of When the sumof the angles at the apices of the oppositely facing cones approaches this figure, it has been found that the wall portion 2 is reinforced to a considerably greater extent than has been obtained in the prior art receptacles wherein'such flanges have been generally disposed in a single plane extending across the top of the upper edge of the sloping wall portion.

In the case of the prior art devices referred to above, the angle of the flange with respect to the wall portion is such that any deflection of the wall tends to produce a bending of the flange in an upward direction since the angle between the wall and the flange is considerably greater than 90 and a condition of stress resistant instability results from such an angular relation. The flange then is generally not sufiiciently stable to perform its function of reinforcing the upper edge of the sloping wall portions.

In the disclosed structure, however, the conical flanged rim is so disposed withrespect tothe wall} that any forces tending to distort the wall will be resisted by the flange which, by reason of the angular relationship maintained, places a maximum amount of the flange material in such a position that its stress resistant properties are effective to the greatest possibleextent in resisting deflection and deformation of the wall 2.

Referring now in particular to Figure 2 of the drawing, it becomes apparent that the disc-like, closed bottom of the receptacle is subject to considerable load imposed by any product confined within the receptacle and that some means must be provided whereby the bottom may be reinforced against bending or other destructive fiexure to which flat sheet elements are subject.

The reinforcing of the disc-like bottom may assume the form of stamped or deep embossed ribs or valleys wherein certain portions of the disc-like bottom are interrupted relative to other portions and wherein the uninterrupted portions are formed in effect into a series of geometric figures so arranged that the uninterrupted portions and the valley portions will resist deflecting or bending loads imposed on the bottom structure. As is clearly evident from the drawing, the reinforcing pattern takes the form of a series of spaced trapezoids 5 radiating outward from a hexagonal offset portion 4. The trapezoids are formed by providing the bottom with radially extending ribs or valleys 7 which extend from the center of the pan outwardly toward the peripheral marginal edge of the bottom structure. The valleys 7 are connected together adjacent the center of the pan bottom by-a further series of valleys 9'so arranged as to generate the shorter edge of the trapezoids 5 as well as to define and circumscribe the centrally disposed hexagonal portion 4 having its respective sides adjacent to the shorter sides of trapezoids 5. The longer sideof the respective trapezoids 5 are disposed toward the outer marginal edge of the bottom surface 3 of the pan. These sides are defined by depressing a portion of the metal such that a downwardly sloping bottom surface 6 is formed which extends from the longer sides of each respective trapezoid outwardly and downwardly toward the annular edge formed by the bottom 3 and its juncture with the sloping wall 2 when the receptacle is in article receiving position.

The bottom 3 of the pan or receptacle therefore may be considered to be provided with a plurality of substantially symmetrical polygons disposed in concentric spaced relationship to each other such as inner hexagon 4, the axis of symmetry of which coincides with the center of the bottom 3-, and an outer hexagon 4. Disposed between these polygons is a series of symmetrically arranged geometrical figures 5. These geometrical figures 5 are partially defined or delineated by the generally radially disposed first series of diametrically interrupted ribs 7. The delineation of these geometrical figures 5 is completed by means of the second series of ribs 9 and, the lines of demarcation 10 that exit between the bottom surface portions 6 of the'receptacle and the main body portions of the geometrical figures 5.

In the preferred embodiment of the invention and reference is made specifically to Figure 3, it may be seen that the ribs or valleys 7 and 0 are comprised of generally V- .4 shaped walls formed integrally of the same metal as the interrupted portions of the respective trapezoids and geometrically figured center 4. The wall portions of the respective geometric figures define sloping, stress-resistant portions converging toward each other to produce V- shaped ribs or valleys which are not susceptible to the same degree of flexure as areembossed rib-like members which include a fiat bottom interposed between spaced converging walls.

Considering now the entire structure, it may be seen that the radially extending ribs or valley portions may be spaced a maximum of-60 from each other such that no continuous or uninterrupted fold lines about which the bottom may be bent exists from any given point on the peripheral marginal edge to any diametrically opposed point on the peripheral marginal edge.

As shown in the drawing the trapezoids are disposed in such a manner that the valleys 7 and 9 are disposed 120 apart at their points ofintersection, presenting no diametrically extending uninterrupted orcontinuous fold line about which the pan or receptacle bottom may flex or bend.- In the particular arrangement, the geometric figure at the center of the receptacle jbottom assumes the form of a hexagon.

Thus the bottom is reinforced insuch a manner that not only is bending thereof by reason of its instability prevented, but also the nature of the embossed reinforcing does not present any fold lines" or diametrically extending weakened areas about whichcollapse of ,the container might occur as has been the case in most of the embossed reinforcing configurations contemplated in the prior art. Also, whereasthe prior art ,receptacles have been made of, for example, aluminum foil or sheet which is about 0.0033 to 0.0035 .inch in thickness, this invention enables the production of such receptacles of thinner gauge metal sheet, especially aluminum foil.

In addition, considerable reinforcement is obtained by the use of the sloping edge 6 extending from the outermost portions of this disc-like bottom generally upwardly, or downwardly as viewed in Figure 2, to the upper edge of the sloping wall portions defining the longer side of the respective trapezoids 5, This position of the sloping wall orients the metal at anangle to the resultant force .vector of all of the forces produced by material carried Within the receptacle rather than disposing the material at a right angle thereto. Since the foil or light metal from which the metal is fabricated has very little resistance to bending underordinary circumstances, the formation of the particular portions 6 such as to generate a conical surface interrupted by the trapezoid and hexagon portions, in .turn interrupted by the ribs or valleys, will dispose a considerable amount of material at an angle such that the resistance of the metal to bending during handling is not dependent solely on the gauge or thickness of the metal. Rather, the destructive and re sistant components are resolved into a series of components comprised of both bending and compression vectors, the result of which is to decrease the bending loads and increase the compressive loads thus placing at least a part of the metal in a position of resisting compression, at which it excels. Thus, the entire bottom of the pan structure is reinforced in such a manner as to enable unusually thin material to perform a load supporting function and resistance to bending or folding not possible with prior art devices even when embossed. Thus, thinner sheet material may be utilized than heretofore practical and the results from the use of such thin material are to effect a considerable reduction in cost of the article, which reduction in cost is passed on to both the ultimate user as well as the commercial user. The competitive position of light sheet foil in such uses is thereby enhanced costwise and its use becomes not only comparably favorable, but in many cases advantageous over materials heretofore used in the prior art.

To reiterate briefly, while an annularv or round receptacle has been described, it must be appreciated that the particular principles underlying the advantages to be gained by the instant invention may be also incorporated in receptacles having a configuration other than annular or round as shown. In all cases it is to be remembered that the disposition of the repsective ofi-set portions of the bottom must be such that no continuous fold line is presented about which the bottom may flex or bend, and in particular, the offset connecting portions, namely, the ribbed or river elements, should be of the V-shaped design as clearly illustrated and described with reference to Figure 3 of the drawing.

Having thus described the invention, what is claimed is as follows:

1. In a thin, light metal foil receptacle including a flanged frusto-conical side wall and an integrally formed disc-like closed bottom, the improvement comprising inverted V-shaped integral reinforcement ribs formed in said receptacle bottom, said ribs being so disposed and diametrically interrupted as to delineate a series of symmetrically arranged geometrical figures, said ribs being interconnected at their innermost terminal ends by a further series of ribs mutually interconnected to form and circumscribe a substantially symmetrical hexagon disposed with its axis of symmetry coinciding with the center of the receptacle bottom, said bottom including further a peripheral edge portion inclined inwardly and upwardly from the plane of the bottom and merging with said series of geometrically delineated figures, said reinforcement ribs and said inclined edge portion serving to resist bending and folding of said receptacle bottom.

2. A thin, light metal receptacle as defined in claim 1, wherein said flange on said frusto-conical side wall is disposed at an angle such that it comprises a further oppositely inclined frusto-conical surface and wherein the sum of the apex angles of the oppositely facing cones, upon generation, closely approximates 180.

3. The combination defined in claim 1, wherein the metal making up said receptacle is thin gauge aluminum foil.

4. In a thin metallic foil receptacle including a flange, a sloping side wall and an integrally formed closed bottom, the improvement comprising integral reinforcing ribs formed in said receptacle bottom, said ribs being so disposed and diametrically interrupted as to delineate a series of symmetrically arranged geometrical figures, said ribs being interconnected at their innermost terminal ends by a further series of ribs mutually interconnected to form and circumscribe a substantially symmetrical polygon disposed with its axis of symmetry coinciding with the center of the receptacle bottom, said bottom further including a peripheral edge portion inclined inwardly and upwardly from the plane of the bottom and merging with said series of geometrically delineated figures, said reinforcing ribs and said inclined edge portion serving to resist bending and folding of said receptacle bottom.

5. A thin metallic foil receptacle as defined in claim 4 wherein said flange and side wallcomprise converging frusto-conical surfaces disposed at such an angle to each other whereby the sum of the apex angles of the 0pposite facing cones formed upon generation of said surfaces closely approximates 6. A thin metallic foil receptable comprising a sloping side wall provided with a flange and an integrally formed closed bottom, said closed bottom having a first series of reinforcing ribs so disposed and diametrically interrupted as to partially delineate a plurality of symmetrically arranged geometrical figures, said ribs being interconnected at their innermost terminal ends by a second series of ribs which circumscribe and form a substantially symmetrical polygon disposed with its axis of symmetry coinciding with the center of the receptacle bottom and said first-mentioned series of ribs also being interconnected at their outermost terminal ends by demarcation lines which circumscribe another symmetrical polygon the shape of which substantially coincides with that of the first-mentioned polygon and said second-mentioned series of ribs and said lines of demarcation completing the delineation of said geometrical figures.

7. A foil receptacle as defined in claim 6 wherein said side wall comprises a frusto-conical surface and said flange on the sidewall is disposed at an angle thereto such that it comprises a further oppositely inclined frustoconical surface and wherein the sum of the apex angles of the oppositely facing cones generated by said surfaces closely approximates 180.

References Cited in the file of this patent UNITED STATES PATENTS 476,340 Wagandt June 7, 1892 1,689,018 Froidevaux Oct. 23, 1928 1,865,742 Chapman July 5, 1932 1,866,035 Hart et al. July 5, 1932 2,036,572 Frost Apr. 7, 1936 2,041,537 Frost May 19, 1936 2,080,125 Frost May 11, 1937 2,170,040 Stuart Aug. 22, 1939 2,174,425 Schlumbohm Sept. 26, 1939 2,673,003 Stewart Mar. 23, 1954 2,703,185 Cook Mar. 1, 1955 2,775,383 Kollman et al. Dec. 25, 1956 FOREIGN PATENTS 8,163 Great Britain 1901