US2671592A - Collapsible container - Google Patents

Description

March 9, 1954 .1. E7; PAGE 2,671,592-

GOLLAPSIBLE CONTAINER Filed May 26, 1951 IIII 9 YINVENTOR.

' JOHN 45. P44 8 BY ATTORNEY March 9, 1954 J. E. PAGE COLLAPSIBLE CONTAINER 7 Sheets-Sheet 2 Filed May 26, 1951 INVENTOR LEM/v 5. PA'E may J @LZQL/ ATTORNEY March 9, 1954 J. 5. PAGE COLLAPSIBLE CONTAINER- Sheets-Sheet 4 Filed May 26, 1951 INVENTOR- JbH/v E. PAGE BY ATTORNEY March 9, 1954 J, 5, PAGE 2,671,592

COLLAPSIBLE CONTAINER Filed May 26, 1951 7 Sheets-Sheet s INVENTOR. for/N 5- A I ATTORNEY March 9, 1954 ,1. E. PAGE COLLAPSIBPE CONTAINER 7 Sheets-Sheet 6 Filed May 26, 1951 INVENTOR. JbH/v 5. P465 ATTORNEY March 1954 J. E. PAGE COLLAPSIBLE CONTAINER 7 Sheets-Sheet 7 Filed May 26, 1951 INVENTOR.

JbH/v 5 PAGE [MW J 64M A TTORNE Y products.

Patented Mar. 9, 1954 COLLAPSIBLE CONTAINER John E. Page, West Cornwall, Conn., assignor to Gibson Patent Containers, Ltd., Sidney, Australia,

a corporation of Australia Application May 26, 1951, Serial No. 228,474

3 Claims.

' This invention relates to collapsible containers,

and more particularly to a container designed for bulk packaging whose component parts maybe fabricated, shipped and stored in collapsed or knock-down condition, t? be thereafter assembled and erected as required for filling with the bulk This application is a continuation-inpart of my co-pending application Serial No. 122,308 filed October 19, 1949, for Container Constructed.

. The cost of manufacturing, shipping, storing and erecting collapsible containers for consumer products normally discarded when the contents have been removed, is an important factor in the overall cost to the consumer of the usable packaged product. The ingenuity of packaging ex- .perts and the packaging industry is constantly being applied to the discovery of ways and means to reduce the overall cost of bulk packaging as by the employment of less expensive and more readily available materials, the maximum use of container materials and reduction of material wastage, the reduction of the labor cost factor in fabricating and assembling, and reduction in shipping and storage space requirements for the container components.

In the packaging of bulk goods and merchandise such as ice creams, frozen fruit juices, and

other semi-liquid and granular products, it has been customary to employ a collapsible tubular body made from paperboard or fiberboard, which can be shipped in substantially flat condition to the merchandise packer, who then applies a bottom construction to the tubular body as the con- .sumer products are packaged therein. Collapsible containers of the type disclosed in my issued Patents Nos. 2,053,678, 2,053,679, and 2,053,680 have been extensively used in the bulk packaging of ice creams and frozen fruit juices, and such containers have heretofore been generally accepted as the most economical packaging medium heretofore devised for the packaging of such bulk products.

This inventionis directed to the provision of an improved collapsible container, which is eminent ly satisfactory for the packaging of bulk products of semi-liquid or granular form, whereby substantial savings in materials, fabricating and assembly labor and overhead, as well as valuable shipping and storing space, may be effected as compared with all other bulk packaging media into tubular form, substantially the entire surface and approximately an inch or less wide.

area of the blank as formed into the tubular body, is employed to contain the product contents. Outturned flaps at each end of the container body and formed as an integral part of the body blank, heretofore considered necessary to provide effective securement of the bottom rim and top rim to the container body, have been completely eliminated by this invention.

Thus by this invention, a substantial saving in paperboard stock normally required to provide the outturned rim locking flaps is effected, and a substantial saving in labor and manufacturing overhead required to outfold the locking flaps and compress the same against the outside face of the blank, is also thereby effected. Additionally, very substantial savings are efiected in transportation and storage costs by the elimination of ie outturned rim locking flanges from the collapsed container body, since collapsed container bodies having outturned locking flanges occupy, when compactly stacked together, approximately twice the space required for container bodies Without such outturned rim locking flanges.

It will be appreciated that collapsible containers for bulk products when fully assembled and set up to receive the contents must have a strong and sturdy bottom construction, securely locked to the bottom end of the container body. An outturned locking flange associated with the lower end of the container body has heretofore been considered the best and most economical means devised for effecting positive securement of the bottom rim to the lower end of the collapsible paperboard container body.

This invention is particularly directed to the provision of a bottom construction which can be tenaciously and rigidly locked to the bottom edge of an expandable paperboard body which does not possess an outturned and upturned rim locking bottom flange, which requires no material fabricating, forming, shaping or clamping operations by the products packer, and which can be fully erected from its component parts by the product's packer either manually or automatically at minimum cost.

In accordance with this invention, a bottom rim and a paperboard bottom disc are all that is required to provide a bottom construction for the unfianged collapsible paperboard body. The rim can be inexpensively made from a thin strip of sheet metal which need be only ten thousandths totwelve thousandths of an inch thick, The metal bottom forming strip is fabricated in the form of a circular rim or hoop having a, side wall section approximately only -inch high an inturned fiange to support the bottom disc approximately of an inch wide, and an inturned lip at the opposite edge of the side Wall section. This inturned lip presents a free edge designed to abut against the outside face of the expanded tubular body when the lower edge of the body is seated against the inside face of the inturned disc supporting flange of the rim. The bottom disc can be economically made from inexpensive paperboard, die cut to provide a flat blank to accurate diametrical dimension.

This invention employs a novel wedge-locking principle to securely and tenaciously lock the bottom rim to the unfianged bottom edge of the container body, without the use of any extraneous securing means whatsoever. The novel wedge-lock principle of this invention translates the weight forces represented by the weight of the container contents, normally tending to strip the bottom rim and bottom disc from the container body, into vector forces which exert downwardly directed compression and bending forces on the relatively stiff bottom skirt portion of the container body as contained within the side wall section of the bottom rim. This invention also takes full advantage of the stiffness and resistance to bending and compression inherent in inexpensive paperboard stock, to effect remarkably strong wedge-locking securement of the metal bottom rim and bottom disc to the container body.

Various other novel features and advantages of this invention will be apparent from the folowin de ription considered in connection with the accompanying drawings, in which;

Fig. 1 is a perspective view of a container constructed in accordance with this invention, certain parts being broken away to illustrate certain details of the bottom construction;

Fig. 2 is a fragmentary cross-sectional view of the container body as viewed along lines 2-2 of Fig. 1 showing more particularly the laminated characteristics of the paperboard and the expansion scoring therein, this view being approximately ten times enlarged over normal;

Fig. 3 is an enlarged fragmentary vertical cross-sectional view of the upper part of the container as viewed along lines 3.3 of Fig. 1 showing more particularly the cover end disc and its associated retaining rim as applied to the container body;

Fig. 4 is a plan view of the outside face of the preferred form of the fully formed container body blank showing the expansion scoring, folding scores and circumferential skirt defining scores impressed therein ready to be folded to provide the tubular body;

Fig. 5 is a perspective view of the body blank shown in Fig. 1 in the process of being folded to provide a collapsed tubular body;

Fig. 6 is a horizontal cross-sectional view of the container body as it would appear when fully assembled into flat collapsed form for stacking;

Fig. '7 is a plan view of the outside face of a body blank of modified form in which the circumferentially extending bending scores have been omitted from the top and bottom ends of the blank;

Fig. 8 is a plan view of the outside face of a body blank of another modified form in which the expansion scores extend the full length of the blank;

Fig. 9 is a plan view of the outside face of a further modified form of body blank in which the expansion scores extend the full length of the blank, with the circumferential bending scores omitted from the bottom and top ends of the blank;

Fig. 10 is a plan view of the outside face of a 4 still further modified form of body blank in which the expansion searing s have been omitted;

Fig. 11 is a plan view of the outside face of a further modified form of body blank in which the vertica1 expansion scores and the circumferential bending scores have been omitted;

Fig. 12 is a top plan view of the bottom rim forming a part of the bottom construction of this improved container;

Fig. 13 is an enlarged fragmentary cross-sectional view of the bottom rim as the same would appear when viewed along the lines I3l3 of Fig. 12;

Fig. 14 is a fragmentary elevational view of the inside fa of t e bo tom r m sh win e ina n w ch the of he band formin th rim may be joined together;

es an en ar e fra men ar top ele ational view of a bottom rim in which the free d f th tur cd bodpp lip h r is roughened or serrated to provide a saw toothed edge;

Fig. 16 is a greatly enlarged fragmentary vertical cross-sectional view of the bottom portion of this improved container illustrating the manner in which the bottom rim, bottom disc and bottom skirt of the container body are wedgelocked together in accordance with this invention to provide a strong, rigid, durable and substantially leak proof bottom construction;

Fig. 17 is a perspective view illustrating the manner in which the bottom skirt portion of the container body may be located and inserted into the bottom rim;

Fig. 18 is a perspective view of the bottom forming disc;

Fig. 19 is a perspective view of the cover forming disc;

Fig. 20 is a vertical cross-sectional view of the bottom portion of the container taken approximately diametrically thereof and showing the bottom disc in process of being forced into wedge locking position within the bottom skirt portion of the container body as set within the bottom mm;

Fig. 21 is another vertical cross-sectional view of the bottom portion of the container as viewed along line 217-21 of Fig. 20, this view illustrating the bowed shape which the oversize bottom disc must assume as it is forced through the rigid throat of the container body in the area embraced by the in-turned lip .Of the bottom rim; and

Fig. 22 another vertical cross-sectional view or" the bottom portion of the container showing the oversize bottom disc during its final insertion stages when expansion stress is imposed on the bottom skirt of the container body.

Similar reference characters refer to similar parts throughout the several views of the draw.- s d e fication- As illustrated in Fig. 1, containers constructed in accordance with this invention comprise a container body A formed from a rectangular blank of paperboard material having the bottom skirt 1 thereof inserted within a bottom rim B which may be economically fabricated from a sin l st i of i t sauce sheet metal A bottom forming disc C, which may be economically formed from inexpensive paperboard of substantial stiffness, is forcibly inserted into the bottom skirt 1 of the container body to seat against the inside face of the 'inturned bottom flange 12 of the bottom rim. The container body A, bottom rim B and bottom disc G are so shaped, proportioned, constituted and assembled as to effect a positive, strong and secure wedging and interlocking action between the bottom disc, bottom rim and bottom skirt of the container body, as hereafter more fully described. Containers constructed in accordance with this invention are admirably adapted for the low-cost packaging of ice creams, fruit juice icings and the like to be later solid frozen. The filled container is provided with a closure cover formed from a paperboard cover disc D locked to the upper skirt portion 9 of the container body by a metal top rim E as illustrated in Figs. 1 and 3.

These improved containers are particularly designed to be manufactured from relatively low .cost materials employing low cost fabrication and assembly procedures, with the use of the very minimum amount of materials. These improved containers provide the ultimate in economy packaging of relatively bulky, heavy and semi-liquid products, and possess the leakproofness and strength which make them particularly desirable for the commercial packaging of such products as ice creams and frozen fruit juices.

The container body A is formed from a rectangular blank of selected paperboard material economically sized and proportioned to eliminate waste in cutting the body blanks from the sheet or roll of paperboard stock. While higher quality and more expensive fiber stock can be used in the fabrication of the container body, containers having a bottom construction made in accordance .with this invention, permit the use of relatively inexpensive paperboard stock having an inner core a sheeted from waste paper or newsprint; and laminated between a thin inner liner 1) sheet made from bleached sulfite for sanitation, and a thin outer liner sheet made from unbleached kraft to give the container body a finished appearance and provide protection to the inner core a. Such paperboard stock is the least expensive fiber stock available to the container in- However, such paperboard stock has definite limitations. In toughness and foldability it is substantially inferior to the more expensive .virgin wood stock or long fiber stock, but it does to five or more gallons of icecreams and ices may advantageously and economically employ inexpensive paperboard stock for the container bodies which calipers from 30 to 40 thousandths .of an inch in thickness, and wherein the major thickness comprises the waste paper pulp core a laminated between thin paper inner and outer liners b and c as above described. As shown in Figs. 4 to 11 inclusive, the container body is made from a paperboard blank shaped to present par- .allel extending top and bottom edges l and 2 and parallel side edges 3. A pair of parallel extending collapsing scores 4 traverse the entire length of the blank, thus dividing the blank into an intermediate section 4 and end sections 4". The intermediate section t as defined between the collapsing scores a is of such width as to extend a distance of 180 around the expanded tubular body. The parallel extending collapsing scores 4 permit folding of the end sections t" to overlie the intermediate section 4 as shown in 'Fig. 5; the combined width of the end sections l being slightly greater than the width of the informed as illustrated in Fig. 7, with the blank termediate section 4 to provide for an overlap 5 at each side of the blank to be secured together by a suitable adhesive 9 applied as a strip to the outside face of the superimposed overlap 5 as shown in Figs. 4 and 5. When the overlap portions 5 of the end sections 4" are thus adhesively secured together, a fiat collapsed body as shown in Fig. 6 is provided. Collapsed container bodies formed as shown in Fig. 6 may be vertically stacked in compact relationship to occupy a very minimum of space in shipment and storage.

As shown in Figs. 4, 8 and 10, the body blank may have a bending score 6 impressed into the paperboard and spaced from and extending parallel to the bottom edge 2 thereof, to thereby deline a bottom skirt 1 which has a width equal to the inside height of the bottom rim B of the container, as more fully described hereafter. A similar score 3 may also be impressed into the paperboard blank to extend parallel to th top horizontal I thereof to define a top skirt portion 9 to be received within the top rim E of the container closure.

To accommodate expansion of the freezing ice creams and ices, and to facilitate cylindrical shaping of the container body, expansion scorings [0 extending longitudinally of the container body are desirably provided as shown in Figs. 4, 7, 8 and 9. The parallel expansion scorings [0 are desirably uniformly spaced approximately three quarters of an inch to one inch apart; each score having a width in the approximate order of of an inch and a depth in the approximate order of five to ten thousandths of an inch.

To facilitate fiat collapse of the container body as shown in Fig. 6, the collapsing scores 4 are desirably formed slightly wider and deeper than the expansion scorings l0, and may be approximately 1%.- of an inch wide and in the order of eight to twelve thousandths of an inch deep. The skirt defining scores or bend lines 6 and 8 extending horizontally across the blank are preferably extremely light and need not be more than five thousandths of an inch in depth. The skirt defining scores 6 and 8, the collapsing scores 4 and the expansion scorings l0 are all sunk into the outer face of the blank, producing very light corresponding protuberances or ribs on the inside face of the blank. It will be noted that the bottom skirt portion 1 and the top skirt portion 9 are not severed. In the blank forms having the expansion scorings, the expansion scorings 50 preferably terminate short of the upper and lower edges I and 2 of the blank, so that the bottom end top skirt portions 1 and 9 are not traversed thereby.

The preferred form of body blank as illustrated in Fig. 4, is provided with the horizontally extending bending scores 6 and B to clearly define the bottom and top skirt portions 1 and 9 thereof, and additionally is provided with the longitudinally extending expansive scorings l0 extending between and terminating at the horizontally extending bending scores 6 and 8.

A. satisfactory body blank for the construction of this improved economy container may also be longitudinally traversed by the collapsing scores 4 and expansion scorings I ii, the horizontally extending scores 5 and 8 employed in the blank shown in Fig. 4 being omitted. However, the top and bottom ends ill of the expansion scorings ill in the blank shown in Fig. 7 terminate inapproximate alignment short of the top and bottom edges of the blank to leave th bottom skirt portion 1 and top skirt portion 9 thereof nnscored thereby.

The container body blank illustrated in Fig. .8, which may also be used in the construction of this improved container, is similar to the body blank shown in Fig. 4 except that the collapsing scores 10 traverse the entire longitudinal length .of the blank, and as thus formed traverse the bottom skirt portion I and the top skirt portion 9 as defined by the horizontally extending scores 6 and 13. The blank shown in Fig. 8 is also provided with the paired collapsing scores 4 to per- ;mit collapse folding of the assembled-container body intotheiorm shown in Fig. 6.

9 illustrates a further modified form .of body forming blank useful in the construction of this improved container in which the horizontally extending bending scores .6 and .8 are .omitted, with the expansion scorings i extend- .ing across the full length of the blank to traverse the undefined bottom skirt portion 1 .and .top skirt portion thereof. Thismodified body blank is provided with the paired collapsing scores .4.to permit flat collapse .of the container body formed therefrom.

111 the form shown in Fig. 10, the body blank is traversed by the horizontally extending scores .6 and .8 which define the bottom skirt portion 1 and the top skirt :portion 9 thereof, the expansionscoring L0 beingomitted.

In its simplest ,form, the .body blank may be constructed as shown in Fig. 11, with the ex pansionscorings 1.0 and the horizontally extending skirt defining scores 6 and 8 omitted, leaving .the rectangular body blank Wholly unscored except for the paired collapsing scores 4. This blank is nevertheless of sufficient length to provide for a bottom skirt portion 1 and a top skirt portion 9 not specifically defined by any horizontally extending bending scores 6 and :8 impressed therein.

The provision of expansion scorings in the body blanks, as illustrated in Figs i, 7, 8 and 9, is normally desirable to facilitate shaping of the container bodies assembled therefrom into true cylindrical form and additionally to provide for a limited expansion of the container bodies during solid freezing of the semi-liquid contents placed therein, but are not essential for the attainment of a satisfactory container constructed in accordance with this invention, and may be omitted as indicated by the body blanks shown in Figs. 10 and 11. However, the paired collapsing scores 4 should be provided to permit .fold-ing of the end sections 4" thereof to overlie the intermediate section 4' with the side edge portions glued together in overlapped relationship, so that the container body which may be flatly collapsed as shown in Fig. 6. All of the various types of body forming blanks used in the construction of these containers are formed from rectangular blanks of paperboard stock,.and have a pair of collapsing scores 4 as a common feature.

Each and all of the various types of body blanks illustrated in Fig. .4 and Figs. 7 to 11 inclusive are adapted to be cut to their true and final- Such 8 the horizontal bending scores 6 and 8, the col.-

lapsing scores 4, and the expansion scorings l0 therein to precise spacing and dimensions in a single pass operation. As thus formed, body blanks in the form shown in Figs. 4, 7, 8 and 9, may be cut and scored at the same high rate of production as the body blanks shown in Figs. 10 and 11.

After the body blanks have been selectively-cut and scored as desired, the blanks are designed to be run through a continuous strip gluing and folding machine equipped with a glue applicator which applies the strip of adhesive g to the outside face of one of the side edge portions '5 of the blank, with folding mechanism which alternatively folds the end sections 4 over the intermediate section 4 in rapid progression, and with a pressure roller which operates to firmly press the overlapped edge portions 5 of the blank into firm adhesive contact and to simultaneously flatten the collapsed body into the compressed form shown in Fig. 6 for compact stacking. The folded and compressed blanks are thus completely assembled economically and at high speed in a single pass through the gluin and fold-ingmachine, and as thus produced are ready for'compact shipment to the product manufacturer for erection and assembly with the supplied bottom rims B and bottom discs C to receive -the-product contents, along with the cover discs '13 and top rim E providing-the container closures.

The bottom rim B constructed and formed as illustrated in Figs. 12, 13 and 14 may be economically made froma relatively thin'gauge strip of sheet metal. In the construction ofcontainers approximately six to ten inches in diameter and of a size to contain from one to five gallons 9! creams or ices, the rim forming metal strip ;may measure approximately oneinch wide and from ten to fifteen 'thousarrdths of an inch in thickness. As formed, the bottom rim ,is in-the shape of a hoop, presenting a side wall section I I, an inturned supporting flange l2, and anjnturned body gripping lip 13. The ends pfthestripmay beninitially connectedras shownin Figs. 12 and 14 by hook portion J4 formed on one end of the'side wall section I I of the strip which is insertedinto a horizontally extending slot "15 formed in the otherend of the side wall section. The ends [2' of the inturned supporting flange l2 and the ends of the n u ed b d gr ping l e ither by brought substantially into abutment.

To strengthen the rim construction and to stiffen the inturned flange I; upon which the bottom disc 0 is s p o t d the f n lep evided with radially extending corrugations .defined by raised mounds l6 separated by corresponding valleys ll, the raised rnounds l6having rounded ends IS. The rounded ends I8 of the mounds define a narrow circumferentially ex.- dins g e fladi ce t t e inside fac I e s e wall se ti n v he i te ned b dy gripping p a ex d i rdly-sub ta t al y parallel to the inturned supporting flange l2, or m y be l ly inclined rds the s por in flange i2 as indicalmgl in Fig."1 3.

T a i e t de i d .w ds hs interlock between the botto ski t .of the cohiame 'hody. the bottom rim B .and bottom disc .0, to the maximum degree, and thereby effect unyielding .securement of the b tt m vrim to the c ntai e body, requires a definite dimensional iintererelartionship between the parts. Thus the (bottom -rinr should conform to definite .diametrical and dimensione condi ions to most .efiectirelydn erlock with the container body and bottom disc of specified diameter. Accurate diametrical formation of the bottom rim can be assured by accurately locating the abutment edge I4 of the hook portion I 4 with respect to the abutment end I5 of which the hook portion I4 is inserted. Thus, when the abutment edge I4 of the inserted hook portion M has been drawn into abutment against the closed end I5 of the slot I5, two or three spot welds 20 may be applied to the overlapped end portions of the side wal1 section I I to thereby firmly fix and permanently secure the shaped rim to accurately established dimension. A definite dimensional relationship must also be established between the height of the side wall section II as well as the width of the inturned body gripping lip I3 in relation to the diameter of the expanded container body and the diameter of the bottom disc C, as will more fully be pointed out hereafter.

The inner edge 2I of the lip is dimensioned to snugly seat against the container body along a circumferential line about which the bottom skirt is flared outwardly when the container is fully assembled. While no circumferential extending groove is required to provide support for the inner edge 2| of the inturned lip of the bottom rim, the lightly impressed bending score 6 may advantageously be applied to the container body to visibly define the bending line against which the inner edge 2| of the lip should seat, thereby facilitating accurate assembly of the container. It will, however, be appreciated that the horizontal bending score 6 may be eliminated from the body forming blank as indicated in the body forming blanks shown in Figs. '7, 9 and 11.

The bottom forming disc C as shown in Figs. 16, 18 and 20 to 22 inclusive may be formed from inexpensive paperboard having a waste paper or newsprint core a, an inner liner formed from a relatively thin sheet of bleached sulfite b for sanitation, and an outer liner 0' formed from a sheet of unbleached kraft for appearance and strength. The bottom disc C is circular to conform with the circular shape of the bottom rim,

and its size is accurately interrelated to the diametrical dimension of the expanded container body and the inside diameter of the side wall section II of the bottom rim with which it is to be associated. The bottom disc C should also possess substantial stiffness and strength. Bottom discs for two and one half and five gallon ice cream containers will possess adequate stiifness if the bottom discs caliper sixty thousandths of an inch in thickness, and need not be over eighty thousandths of an inch in thickness to adequately support and contain two and one half to five gallons of creams or juices. A plurality of bottom discs may be die cut from a paperboard stock sheet in a single die cutting operation at high production speeds with a minimum of waste material resulting. The bottom discs are accurately shaped to dimensional requirements by the die cutting operation, so that no further fabricating operation thereon is required. The fiat bottom discs may be compactly stacked together for shipment to the product manufacturer for use in assembling the containers as required.

The compactly stacked container bodies and bottom discs along with the compactly bundled bottom rims as shipped to the products manufacturer or packer, can be stored in a minimum of space and maintained in clean and sanitary condition for assembling into the containers as required. In assembling the container, the container body A is partially expanded as shown in Fig. 17 while the body is gripped adjacent the collapsing scores 4, and by exerting inward pressure thereon, the bottom skirt portion 7 thereof may be readily inserted into the bottom rim. By the application of outward pressure applied to the inside face of the container body, the container body will then spring out into cylindrical form. Downward pressure is exerted against the top edge I of the container body to make sure that the bottom edge 2 thereof is snugly seated against the inturned supporting flange I2 of the bottom rim B. The width of the bottom skirt portion 1 is such as to seat between the free edge 2I of the inturned body gripping lip I3 and the inturned supporting flange I2 of the bottom rim. Full insertion of the bottom skirt portion 7 into the bottom rim may be made visibly evident by the provision of the circumferentially extending bottom score or marking line 6 therein, against which the inner edge 2i of the rim lip 13 is to abut.

The bottom disc is then telescoped through the open upper end of the container body and pressure forced downwardly. The bottom disc C is of such oversize diameter that when located in its final seating position against the inside face of the inturned supporting flange ll of the rim, the lower edge section I of the bottom skirt portion 7 is firmly clamped and compressed between the peripheral edge 25 of the bottom disc and the adjacent inside face of the side wall section H of the bottom rim, as shown in Fig. 16. As finally assembled, the lower edge 2 of the container body will be partially inserted into the narrower circumferentially extending groove I9 of the bottom rim, and partially seated against the rounded end portions IB of the corrugating mounds It.

To effect full insertion of the oversize bottom disc C into the container body, it will be appreciated that the bottom disc must be forced past the contracted throat 26 of the container body which is rigidly held to a fixed diametrical dimension by the pressure exerted by the inner edge 2| of the rim lip I3 surrounding the container body at this point. The bottom disc C is of such oversize dimension that it could not be forced through the contacted throat 26 of the container body if this were attempted when the disc is maintained parallel to the contracted throat 26. Insertion of the disc through the contracted throat may, however, be readily accomplished when the disc is inserted in inclined posi tion as indicated in Fig. 20. As shown in Fig. 20, one end section 27 of the disc is first inserted to extend below the contracted throat 25, leaving the oppositev end section 23 extending above the throat 255 and resting against the adjacent inside face of the container body above the contracted throat 25.

The intermediate section 25 of the bottom disc will then be pinched between the adjacent parts 26' of the contracted throat 26, causing the center section so of the disc to bow downwardly in accordance with the pressure applied as shown in Fig. 21. Continued downward force applied to the intermediate section 29 of the disc progressively forces the opposite peripheral edges of the discs past the contracted throat 26 of the container body, causing the inserted end section 2! of the disc to shift laterally to press against and outwardly flare the adjacent part of the bottom skirt portion l of the container body, as shown in Fig. 22. By the application of progressive pressure against the bottom disc, starting at a point adjacent the inserted end' section 2'! l 1 thereof and proceeding across the intermediate section. 29 thereof, the opposite end section 28 may be forced. past the contracted throat 26 of the container body so that the disc will press the adjacent portions of the yieldable bottom skirt portion 1 of the container body outwardly and permit the bottom disc to flatten when finally seated against the inturned flange portion l2- of the bottom rim.

Since the oversize bottom disc is approximately twice the thickness of the container body wall, the peripheral edge 25 of the bottom disc as. finally seated against the rim flange i2, will flatten and maintain the skirt portion l flared outwardly in the manner shown in the greatly enlarged crosssectional view of Fig. 16. When the bottom disc is thus fully seated, the bottom edge section i of the skirt portion '1 will be tightly pinched. and. compressed between the peripheral edge 25 of. the bottom disc and the adjacent inside face of the side wall section H of the bottom rim, thereby providing a tight and substantially leakproof fit between the peripheral edge 25' of. the bottom disc and the compressed inside face of the bottom skirt portion 1.

The outer diameter of the expanded container body A is'such as to be snugly received. within the opening defined by the inner edge 2! of the rim lip l3 without pinching or cramping the body. As-fully assembled, the free edge 2i of the rim li-p l3 will snugly abut against the outer face of the expanded body along the circumferential bend line or score 5,v with the bottom edge 2 of the body snugly seated against the inside face of the rim flange l2. The lower edge section I of the bottom skirt 1 will also be firmly gripped between the disc periphery 25' and the adjacent inside face portion H" of the rim side wall section II, with the bottom skirt '1 flaring outwardly in an amount-determined by the extent to which the inner edge 21 of the rim lip 13 inwardly overhangs the body contacted facing portion H of the rim side wall section Ii. As thus constructed, it will be appreciated that the application of the score line 6 to the body blank is optional, since a corresponding bend line 6 would naturally be formed upon outward flaring of the bottom skirt 1.

As thus assembled, the bottom rim B and the oversize paper board bottom disc C are firmly secured to the bottom skirt 1 of the container body by a wedge-locking action. The wedgelocking action of this invention translates weight forces represented by the weight of the container contents, normally tending to strip the bottom rim and bottom disc from the container body into vector forces which exert downwardly directed compression and bending forces on the bottom skirt of the container body. By the correct application of the wedge-locking principle of this invention, an increase in contents weight results in a correspond ng increase in the forces operating to retain the bottom skirt securely locked within the bottom rim. The inherent stiffness and resistance to bending and compression of this inexpensive paperboard stock, often considered an undesirable characterist c in the manufacture of cylindrical containers, is used to remarkable advantage in eifecting the wedgelocking action of this invention, whereby a strong and tenacious locking securement of the metal bottom rim and bottom disc to the container body is achieved.

There is illustrated in Fig. 16 a diagram of the forces acting upon the bottom disc C, bottom rim B and container body A as assembled in accordance with the \ivedge lockingv principle of this; in vention. The weight is represented by the letter R, and the compression forces pinching the lower edge section 1 of the body skirt 1 between the peripheral edge 25- of. the bottom disc and the adjacent inside facing area I I of. the bottom rim, is represented by the letter T. It would normally appear that when upward lifting force S. is applied. to the. container body, that the substantial downward weight R applied against the bottom disc C and bottom. flange E2 of the metal rim would operateto strip the bottom rim from the container body.

By the employment of the wedge-locking principle of this invention, an opposite effect from that normally expected is in fact attained, through. vector forces operating to wedge and firmly secure the relatively stiff bottom. skirt 1 of the container body within the bottom rim. In accordance with this invention, the contents load R is transmitted to the sidewall section. ll of the rim as an equal downward force U. The downward force. U' transmits an. equal downward force V at the edge-2 I. of the rimlip l-3. Since the free edge 2| of the. rim lip I3 abuts against the container body at the bend. line 6, this vertical downward force V is transferred to the upper end of the. relatively stiff bottom. skirt 1 of the container body. The downward force V directed against the upper end. of the flared skirt 1 is transformed. into two vector components. One of the vector components Vi. acts in. a vertical direction, tending to bend the bottom skirt. 1 of the container body. This bending force is resisted by the inherent stiffness of the paperboard stock from which. it is made. The other vector force component. V2 acts along the center line of the flared skirt I, tending to drive the extreme lower edge 2 thereof tighter against the bottomflange A2 of the bottom rim B on which seats, andto additionally exert a compression force lengthwise of the bottom skirt portion 1 which is also resisted by its inherent stiffness.

Thus the wedge-locking action of this invention operates to, (a) drive the extreme lower edge 2 of the bottom skirt T tightly against the bottom flange l2 of the weight loaded container, ('17) exert abending force on the bottom skirt T which is resisted by its natural stiffness, and, finally (0) exert a lengthwise compression force on the bottom skirt which is also resisted by its natural stiifness. Thus the wedge-locking action of this invention takesv full advantage of the st finess characteristics of relatively inexpensive paperboard from which the contanier body and the oversize bottom disc are made.

Full utilization of the wedge-locking principle of this invention to thereby attain a bottom construction of maximum strength, requires a definite inter-relationship between the thickness, sizes and dimensional measurements of the parts forming the bottom construction be maintained, as is evident by referring more particularly to Fig. 16 wherein the container parts as shown are approximately ten times enlarged over normal.

To attain the maximum wedge-locking action, the bottom skirt 1 of the container body should be flared outwardly at a sufiicient inclination to prevent slippage of the inner edge 2| of the rim lip 13 downwardly along the flared skirt when the assembled container is loaded with contents. This angle of inclination, as indicated by the letter w in Fig. 16, should closely approximate 10, with a possible variation of from.8 to 12".,

Additionally, the peripheral edge 25 ofthe bot- 13 tom disc C should flt tightly against the lower edge section 1' of the bottom skirt i so that the edge section 1' is pinched and compressed between the disc periphery 25 and the adjacent side wall area ll of the bottom rim. This pinching action serves to rigidly locate the edge section 1' and prevents lateral movement or sway of the relatively stiff bottom skirt 1, but is not relied upon to frictionally grip the bottom skirt portion against withdrawal. A tight fit between the peripheral edge 25 and the bottom disc C and the lower edge section 1' of the skirt also materially contributes to the leak-tightness of the container.

The lower edge 2 of the container body should seat snugly against the top face of the bottom flange l2 of the rim so that the peripheral edge 25 of the bottom disc has maximum peripheral pinching contact with lower edge section 7 of the bottom skirt.

The bottom disc C should also possess substantial stiffness and resistance to bending, it should not be weakened by scoring, and it should seat flatly and firmly against the inside face of the rim flange l2. Bottom discs C having a diameter of six to ten inches, useful in the assembly of ice cream containers of the normally used two and one half gallon and five gallon size, will possess the required stiffness when made from paperboard having a waste paper core a. laminated between liner sheets b' and when the paperboard calipers from seventy to eighty-five thousandths of an inch in thickness. Paperboard bottom discs used for ice cream containers of this size, preferably should not caliper less than sixty thousandths of an inch in thickness, and need not exceed ninety thousandths of an inch in thickness.

The bottom skirt 1 of the body stock should not be cut or split, but should be in the form of a continuous rim, and should have substantial stiffness. Thus the paperboard stock from which the container body is made should have substantial stifiness and tensile strength. Paperboard stock having a waste paper core a laminated between inner and outer liner sheets a and 19, provides an advantageous and low cost material from which to fabricate the container body. Where such paperboard stock is used to make container bodies for two and one half gallon and five gallon size ice cream containers, the paperboard thickness may approximate thirty to forty thousandths of an inch as an average, should not normally be below approximately twenty-five thousandths of an inch in thickness, and need not be substantially greater than forty thousandths of an inch in thickness.

' Since the expanded tubular container body is dimensioned to snugly fit within the circular area defined by the inner edge 2! of the rim lip l 3, and since the container body as fully expanded normally assumes substantially cylindrical form, it will be appreciated that outward flaring of the bottom skirt 7 thereof to an angle of inclination from 8 to 12, requires that the uncut and unsevered bottom skirt I be correspondingly stretched, with a maximum stretch occurring at the lower edge section I of the skirt when the container is fully assembled. The amount which the bottom skirt of the container body may thus be stretched depends upon the stretch characteristics of the material from which it is made. It has been found that paperboard stock which calipers in the order of thirty to fourty thousandths of an inch in thickness, may be safely stretched or expanded from 1% to 2% without rupture, or a mean average stretch of approxi- 14 mately 1 The maximum stretch characteristic of the paperboard used for the container body is a factor which must be considered in de-' termining the height of the bottom skirt portion I whose outward flare should be in the order of 8 to 12, and is likewise a factor to be considered in determining the inside height 12 of the bottom rim as indicated in Fig. 16.

The inside height 20 of the bottom rim, as well as the distance m which the free edge 2| of the rim lip I3 overhangs the body contact area I I of the rim side wall section II, are also closely inter-related with the stiflness characteristics of the bottom disc as well as its diameter. As heretofore pointed out, the relatively stiff bottom disc C must be inserted through the contracted throat 26 of the container body, as rigidly held by the pressure exerted against the outside face thereof by the circumferential inner edge 2| of the rim I3. Since the bottom disc must also be relatively stiff in order to firmly press the flared bottom skirt section 1 against the inside facing area I I of the bottom rim, it will be appreciated that the area of the contracted throat 26 and lip overhang m with respect to the body contacting surface H as well as the inside height 10 of the bottom rim, must be such as to permit the bottom disc to be forcibly driven through the contracted throat 26 in the manner indicated in Figs. 20, 21 and 22 and heretofore explained.

To illustrate the inter-relationship between thicknesses, sizes and stiifness characteristics of the various parts, containers made to contain from two and one half to five gallons of ice cream or frozen ices may be taken by way of example. Such containers may employ a bottom rim B having an outside diameter of approximately 9.5 inches made from metal strip calipering approximately twelve thousandths of an inch thick, a container body made from paperboard stock calipering approximately thirty to forty thou-. sandths of an inch in thickness, and a paperboard bottom disc C measuring approximately ti} inches in diameter and calipering approximately eighty thousandths of an inch in thickness. The bottom rim B may have an inturned bottom flange l2 approximately three tenths of an inch wide and corrugated to increase its overall thickness to about forty-five thousandths of an inch. The rim lip l3 should terminate in a circular edge 2! which may be relatively smooth, or if desired, may be provided with very fine saw-tooth serrations 2| as shown in Fig. 15. The vertical side wall section II of the bottom rim may extend substantially perpendicular to the bottom flange I 2 thereof, or the side wall section may be inwardly inclined to correspondingly reduce the width of the inwardly extending lip 13. However made, it is important to provide the upper edge of the side wall section II with an inwardly extending lip E3 to define a rigid inturned edge 2! which abuts edgewise Izggceiinst the outside surface of the container For such a container, the paperboard body blank may have an overall width of approximately thirty to thirty-one inches, with provision made for glue overlapping of the side edge portions5 of the blank. When such a body blank made from paperboard. comprising a waste paper core a laminated between inner and outer liner sheets 22 and c and calipering approximately thirty to forty thousandths of an inch in thickness, is shaped into a tubular form, it has been found that the bottom skirt section I may be circum- 15 ferentially stretchcdby the oversize bottom disc approximately one half inch or approximately 1.5%, without rupture.

Using a bottom rim having an overall outside height h of. fifty-five hundredths' of an inch, or an inside height p (as measured from the inside face of the bottom flange 1.2 to the inside face of the lip edge 2|) of approximately forty-nine hundredths of an inch, it has been found that lip edge 2| may overhang the body contacting face portion I I" of the-bottom rim approximately five hundred-tbs toeight hundredths of an inch, to obtain an angle of inclination of. from 8 to 12 for the outwardly flared bottom skirt 1; and with a lip overhang of approximately seven hundredths of an inch, the bottom skirt 1 may be given. an angle of inclination of approximately 10.

The stretch limitations of. the paperboard body stock: imposes a. definite limitation on the inside height p of. the bottom rim, since the bottom skirt 1 of the container body should have an angle of inclination of not less than 8 and preferably in the order of 9 to 12 if the bottom construction is to be held with maximum wedge-locking action. A material increase in the height of the metal rim beyond its necessary height, would not only require the use of addi tional. valuable metal in its formation, but would also require a corresponding increase in the amount of lip overhang m, and correspondingly reduce the area of. the throat 26 through which the stiff oversize bottom disc must be inserted.

Areduction in. the inside height 10 of the bottom rim, would require a corresponding reduction in the amount of the lip overhang m ..if theinclination. angle of the bottom skirt 1- is to be maintained between 8 and 12; Since the stiff oversize bottom disc must be warped. into position as progressively indicated in Figs. 20-, 21 and 22-, s

difficulty would be encountered in effecting full insertion of the bottom disc if the inside height p of the bottom rim was substantially reduced below the relative proportions indicated in Fig, 16.

When construs ing containers whose bottom rim measures approximately nine and one half inches in outside diameter, it hasbeen found that the wedge-locking principle of this invention may most advantageously be achieved whenv the lip overhang m is in the order of five to nine hundredths of an inch, with a mean average of approximately seven hundredths of an inch, and where the inside height p of. the bottomv rim is in the order of. thirty-five hundredths to sixty hundredths of an inch, and preferably with a mean average in the approximate order of fortysix hundredths to fift hundredths of an inch.

By the proper utilization of the wedge-locking principle of. this invention, as above described, a bottom construction of remarkable strength may be provided. Tests have demonstrated that these containers may be loaded with contents weighing from twenty-five to forty-five pounds and roughly handled as thus loaded, with. no discernible movement between the interlocked parts. Additionally, bottom constructions made in accordance with this invention are substantially leakproof, are highly economical to manufacture and assemble, andare admirably adapted for the two and one half. and five gallon packaging of ice creams and fruit juices. While certain novel features of this invention have been disclosed and are pointed out in the 16 annexed claims, it will be understood that various omissions, substitutions and changes may be madeby those skilled in the art, without departing from the spirit of the invention.

What is claimed is:

l. A. knock-down paperboard container of the type which is adapted to be shipped in a substantially fiat condition and to be set up mandaily at the point of use, comprising a tubular paper board body member scored along lines parallel to its axis, a metallic band for suspending a closure at the lower end of said body member, said band comprising a central part of substantially cylindrical shape having an inturned upper lip integral'with said cylindrical part along its upper edge and extending inwardly substantially at right angles to a plane tangent to said cylindrical part, the inner edge of said. lip defining a circular opening smaller in diameter than the diameter of said cylindrical part, and an inturned lower annulus integral with said cylindrical part along its lower edge and extending inwardly and substantially in a plane parallel to that or" the upper lip, and a stiiI fiat circular paperboard bottom closure disc, greater in diameter than the diameter of the opening defined by the inner edge of said lip, seated within the body member with the lower surface or" the: disc substantially in the plane of the lower edge or the body member and in contact with the lower annulus of said metallic band, said body member pressing outwardly against the edge of said upper lip, the portion thereof below said lip: being of substantially the same thickness as the portions thereabove and having the form of: a

frus-tum of. a cone with the minor: base. of said irustum substantially in the plane of the upper lipof the band and the major base of said frustum substantially in the plane of the bottom closure disc, and with the bottom closure disc exerting a radial force against the inner surface of the body adjacent the major base of. said frustum.

2. A knock-down paperboard container as described in claim. 1 having a circular paperboard disc secured to the upper end of said. body member.

3. A knock-down paperboard container as described in claim 1 in which the body member has an endless circumferential corrugation-like bending score formed therein and spaced from and. adjacent to the edge of said body member atthe lower end thereof and parallel to said edge, and. said bending score is engaged with the inner edge of said lip, whereby the bending score defines a predetermined line of transition along which the paperboard body is distorted from cylindrical. form existing above said line to conical form existing below the same.

JOHN E. PAGE;

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 825,878 C'randal' July 10, 1906 2,053,680 Page Sept. 8, 1936 2,062,112 Wilson Nov. 24-, 1936 2,089,527 Andrew Aug. 10', 1937 2,141,717 Lebold Dec. 2'7, 1938 2,208,065 Annen July 16, 1940 2,304,615 Wansker Dec. 8, 1942 2,382,035 Wilcox Aug. 14, 1945 2,577,148 Page Dec. 4, 1951

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