US3338407A - Carton and carton blank therefor - Google Patents

Description

Aug 29, 1967 E. H. CARLSON 3,338AU7 CARTON AND CARTON BLANK THEREFOR Filed April 1l, 1966 5 Sheets-Sheet i BY @www m' ATTORNEYS ug. 29, 1967 E. H. CARLSON CARTON AND CARTON BLANK THEREFOR 5 Sheets-Sheet 2 Filed April ll, 1965 W! .m au I N a@ ma [fill 7 m Q0# ATTORNEYS 5 Sheets-sneu s INVENTOR.

E. H. CARLSON Aug. 29, 1967 CARTON AND CARTON BLANK THEREFOR Filed April u, 1966 zii?. Z v, ATTORNEYS United States Patent 3,338,407 CARTON AND CARTON BLANK THEREFOR Eric H. Carlson, Wilmette, Ill., assignor to Kerr Chemicals, Inc., Des Plaines, Ill., a corporation of Illinois Filed Apr. 11, 1966, Ser. No. 541,711 5 Claims. (Cl. 20G-65) ABSTRACT 0F THE DISCLOSURE A carton blank for an endwise collapsible container adapted to package a pair of aerosol-type cans in inoperative association for shipment, and adapted when collapsed to bring said cans into operative association for use of the contents of the cans.

i Cross-reference to related application This is a continuation-in-part application of applicants copending application Ser. No. 440,133, led Mar. 16, 1965.

This invention relates to a package of aerosol cans and to a carton and to .a carton blank for use in making such a package.

In the making of foamed resins it has been proposed,

as in the Lackland application Ser. No. 471,276, led July 12, 1965, and commonly owned herewith, to package components of the resin-forming composition in separate aerosol cans, one containing a pre-formed polymer, or partial polymer, or some of the constituents thereof in a non-reacting condition, and the other containing a reaction instigatfin-g component, including a catalyst and a liqueteld propellant that is normally a gas and that -is under greater compression than the contents of the rst aerosol can. A mixing of the contents of two cans can be accomplished by the -use of suitably designed valve-controlled dispensing mechanisms, so arranged and constructed that when the dispensing ends of the aerosol cans are placed in properly aligned relationship for the cooperative action of the respective valve mechanisms and the cans are forced together, the contents of the more highly pressurized can will be discharged into the other can for admixture with the contents thereof. After a short period of shaking the can that now contains all of the ingredients of the resinforming composition, the reaction mixture therein is ready to be discharged at whatever site is chosen for the build-up of the foamed resin. Such a two-can system being readily portable, this facilitates the delivery of the resin-forming mixture wherever the foamed resin is needed for insulation or other purposes. Y

' VThe carton of my present invention is designed to contain two aerosol cans such as described and to facilitate the mixing of the contents of the two cans while still .in the resulting package. The packaging arrangement is such that it is impossible for the contents of the cans to be mixed inadvertently while -in storage or at any time before intentional use of the package. Additionally, in order to reduce any hazard during the mixing of the contents of the two cans, the carton is provided with releasa'ble means for locking the carton closed until the mixing of the contents vof the two cans has been completed.

The carton of my invention is formed from a one-piece blank of sheet-like material, such as berboard or the like, which is so formed and arranged with score lines, or other lines of weakness, slits and interlocking tabs, as to be readily foldable to erect the blank into the form of a carton having the `special features adapting it for the twocan aerosol system just described. These special features include a removable knock-out portion in one of the side panels of the carton that, when removed, forms an opening. A door-forming ap is provided for closing such opening, and a spacing member is provided that is adapted to be inserted through said opening and positioned between the packaged aerosol cans to thereby prevent premature actuation of their dispensing valves.

Another special feature of my carton is the provision of transverse lines of weakness in the sidewalls and in the door-forming flap of the carton that permit the carton to be collapsed endwise, after-the'removal of the spacing member, to effect actuation of the valves of the two cans and the transfer of the contents of one can into the other while the carton is in a closed and locked condition. In such condition the carton not only aords protection to the operator, but also facilitates the shaking of the aerosol cans if that is necessary to bring about the desired reaction. After being shaken for a few minutes, the package can be opened manually with considerable ease, and the one can that now contains the complete admixture, removed from the carton for use. The carton .and the remaining, now empty can are then discarded. Since the carton can be made of relatively inexpensive material at a relatively low manufacturing cost, and since the aerosol cans are of the conventional type and are themselves relatively inexpensive, my system of packaging -a pair of aerosol cans for the purposes described is an entirely feasible one.

It is therefore an important object of this invention to provide a blank and carton for forming into a package for a pair of aerosol cans wherein the carton for packaging the cans is so constructed and arranged as to facilitate shipment of the cans and the manipulation of them in the transfer of the contents of one can into the other `at the site where the contents are to be used, as, for example, in the foaming-in-place of a resin foam.

It is a further important object of this invention to provide a carton of the type described that, when used to package two aerosol cans, is free from hazard to the user and that includes means for preventing an accidental or unintended mixing of the contents of the two cans, while facilitating such mixing without removal of the cans from the carton until the desired reaction between the contents of the two cans has been completed.

Other and further objects of this invention will become apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings, which, by way of a preferred example only, illustrate an embodiment of my invention:

On the drawings:

FIG. 1 is a perspective, elevational view of a package of a pair of aerosol cans wherein the blank, carton and the resulting package embody the principles of my invention;

FIG. 2 is a top plan view of a one-piece blank suitable for making the carton of FIG. 1;

FIG. 3 is a perspective plan view of aspacer member forming apart of the package of FIG. 1;

FIG. 4 is an enlarged vertical sectional view taken substantially along the line IV-IV of FIG. 1, showing the pair of aerosol cans in elevation and illustrating the posivided for the purpose;

FIG. 6 is a fragmentary elevational view similar to FIG, 5, but with the spacer member removed;

FIG. 7 is a view similar to FIG. 6 after endise collapsing of the carton and the interengagement of the valved dispensing mechanisms of the two aerosol cans during the act of transferring the contents from one can to the other',

FIG. 8 is a further enlarged fragmentary elevational view, partially broken away and in section, illustrating the position of the dispensing portions of the two cans in an engaging but inactive relationship;

FIG. 9 is a view similar to FIG. 8, but with the dispensing portions of the two cans in active, cooperative relationship for effecting the transfer of the contents of one can into the other; and

FIG. 10 is a sectional view of the valve dispensing mechanism of the upper of the two cans after disengagement from the lower can.

As shown on the drawings:

The reference numeral 10 indicates generally a package embodying the principles of my invention. Said package includes a carton generally represented by the reference numeral 11 and a pair of aerosol cans 12 and 13, which as best shown in FIG. 4, are contained within the carton 11 in endwise relationship with the annular reduced ends 14 and 15, respectively, opposed to one another. If it be assumed that the package is shown in its upright position, as in FIG. l, the lower Kcan 13 is upright and the upper can 12 is inverted with a spacer member 16, to be described later, separating the reduced ends 14 and 15 of the respective cans.

For ease of understanding of the construction of the carton 11, the blank from which it is formed will be described first, and the same reference numerals will be applied to the carton, after erection, insofar as is feasible, as are applied to corresponding elements and structural features of the blank.

As illustrated in FIG. 2, a cartonforming blank indicated as a whole by the reference numeral 17, comprises a one-piece fiat sheet of material that has been die-cut or otherwise formed, and provided with slits and lines of fold, score lines and the like, positioned and arranged as required for the erection of the blank into the form of the carton 11. Where the expression lines of weakness is used herein, it may refer to score lines or to other lines of reduced resistance to folding, along which a folding is to take place or by virtue of which a complete removal of a portion of the carton wall can be effected, as in the case of a knock-out.

In its broader aspects, the blank 17 comprises four elongated, sidewall forming panels 18, 19, 20 and 21, all of which are rectangular in shape and of substantially the same dimensions, so that the preferred form of carton is one that has a square cross-section only slightly larger in size than the size required for accommodation of the cans 12 and 13. The panels 18, 19, 20 and 21 are joined respectively to lines of fold 22, 23 and 24, extending continuously the full distance between transverse lines of fold 25 and 26, except for slits provided in the lines of fold that will be described later. The lines of fold 22, 23 and 24 are sometimes referred to as edge-forming lines of fold. The transverse line of fold 25 extends substantially continuously across the blank from the line of fold 22 to a remote free edge 28 to define one set of the end edges of said panels 19, 20 and 21. The transverse line of fold 26 extends across the other ends of panels 18, 19 and 21 from a line of fold 27-27a at the side edge of the panel 18 to the free edge portion 28a forming an extension of the edge 28. A pair of spaced joint-forming flaps 29 and 30 extend beyond the line of fold 27-27a. In setting up the carton, said flaps 29 and 30 are secured inwardly of the free edge 28-28a to the front side of the panel 21 as Viewed in FIG. 2. An adhesive may be applied to the rear faces of the joint-forming iiaps 29 and 30 and the joint, as at 31 (FIG. 6), with the panel 21 formed by heat, or heat and pressure, or any conventional method of forming the joint 31 may be employed.

A door-forming ap 32 projects from a line of fold 33 that extends between and in alignment with the free edge portions 28-28a of the panel 21. Said door-forming flap 32 has a pair of spaced tabs 34 and 35 hingedly extending therefrom at the ends of the free edge 36 of said liap 32 and foldable about lines of fold 37 and 38. Said doorforming flap 32 functions to close an opening 65 (to be described more fully in connection with FIGS. 5, 6 and 7) formed by removing a knock-out portion 39 formed by lines of perforations 40 and 41 in the panel 18 and extending completely thereacross symmetrically about the median line of said panel 18. A plurality of score lines 42, 43 and 44 extend in parallel spaced relationship across the panels 19, 20 and 21 and also across the doorforming fiap 32 all the way from the line of fold 22 to the free edge 36 of said flap. These lines of fold 42, 43 and 44 may be score lines or lines of weakness, the purpose of which will later appear, but it is sutiicient here to note that the bands 109 and 110 between the score lines 42 and 44 form, in general, a continuation of the knockout portion 39 and lie within the longitudinal spacing of extensions of the lines of weakness 40 and 41 defining said knock-out portion 39.

A plurality of end closure-forming flaps 46, 47 and 48 extend beyond the line of fold 25 joining said extensions, respectively, with one end of each of the panels 19, 20 and 21. Similarly, end closure-forming flaps 46a, 47a and 48a extend beyond the line of fold 26 that joins them with the corresponding panels 19, 18 and 21, respectively. Narrow extensions 45 and 45a, which are identically formed to project in opposite directions from panels 1S and 20, respectively, are formed with integral tabs 49 and 49a that are foldable about score lines 50 and 50a aligned, respectively, with the free edges 25a and 26a of said panels 18 and 20.

As will be explained more fully as this description proceeds, the tabs 49 and 49a cooperate, respectively, with the flaps 47 and 47a to permit the latter to provide outer end closure walls. For this purpose the aps 47a and 47 are formed with transverse lines of fold 50a and 50 that are interrupted by central slits 51a and 51 for receiving the tabs 49a and 49, respectively. The lines of fold 50 and 50a are also provided with inwardly extending short slits 51h, 51C and 51d, 51C, respectively, to facilitate the operation of closing the ends of the carton 11. For further facilitating this same operation, the edges of the end aps 46 and 46a along oppositely directed sides, as at 46b and 46c, are stepped and the edges of the end aps 48 and 48a along oppositely directed sides, as at the edges 48b and 48e, are similarly stepped.

The end closure-forming flaps 46, 47 and 48 are rendered freely foldable about the line of fold 25 by providing suicient clearance at 59 and 60 between confronting edges of the tab 47 and the tabs 46 and 48. Similarly the confronting edges of the flaps 47a and 46a are provided with sutiicient clearance 59a to prevent binding therebetween during the end closure operation.

Slits 63 and 64 are formed in substantial alignment with the edge-forming line of fold 22 in spaced relation from one another to receive, when the carton is erected, the tabs 34 and 35 on the door-forming iap 32. In swinging the door-forming flap 32 about the line of fold 33 to close the opening 65 provided by the knock-out portion 39, the lia-p 32 is moved into a position overlying said panel 18, and to hold it in that position the tabs 34 and 35 are inserted into the slots 63 and 64, respectively, to be engaged therein.

Referring now more specifically to FIGS. 4 and 5, after erection of the carton 11 and with the upper end closure that includes the iiaps 46, 47 and 48 open, the aerosol can 13 is first inserted into the carton to bottom against the lower end thereof that is closed by the flaps 46a, 48a, and the flap 47a when the latter is engaged by the tab 49a. The can 13 lits snugly against the bottom of the carton between the side walls thereof. With the doorforming iiap 32 open and the knock-out portion 39 removed (FIG. 5), the spacer member 16 is inserted through the opening 65 that is provided for the insertion and removal of said spacer member 16.

As best shown in FIG. 3, the spacer member 16 suitably comprises a square of double-faced corrugated board 66 having a slot 67 extending inwardly from one edge thereof to terminate in a central circular opening 68. The function of this slot and opening will be apparent as the description proceeds.

vAfter the lower aerosol can 13 has been inserted intov place and the spacer member 16 properly positioned, the upper can 12 is inserted in an inverted position through the open upper end of the carton. During such insertion, a downwardly and axially extending tube 69 forming a part of the valved dispensing mechanism of the can 12 becomes automatically aligned with an opening 70 (FIG. 8) in a conventional closure-forming part of the can 13. With the spacer member 16 inserted edgewise in a horizontal plane, the tube 69 extends through the central opening 68 of the spacer member. Said spacer member 16 is of such thickness that the beaded bottom 170 of the upper can 12 abuts the inside of the upper end of the carton when closed by the end flaps 46 and 48 and the interengagement of the tab 49 with the flap 47. A snug fit is provided between the beaded bottom 170 of the upper can 12 and the inside of the carton 11.

As best shown in FIGS. 8 and 9, the valved dispensing mechanism of the bottom can 13 includes a central upstanding boss or housing 72 formed integrally with and coaxially of the cap 71. The opening 70, previously referred to, is formed in said housing 72 axially thereof and in alignment with a down tube 73 connected to and dependent from a tubular connector 74 that is secured at its-upperend 75 above an annular bead 76 of said housing 72. Said upper end 75 presses against the upper end of said housing the annular periphery 77 of a valve 78 formed of rubber or other distensible and resilient plastic material. Said valve 78 includes a circular central aperture 79 through which the tube 69 of the upper can is also inserted in lassembling the cans in the carton. At this inoperative stage, the valve 78 is held in its upwardly flexed condition (FIG. 8), thereby closing the opening -70 and sealing the opening 79. Such closure is effected by a compression spring 80 acting through a plug 81 against said valve 78. Said plug 81 has guiding ribs 82 providing flow passages around said plug, and said plug has an upstanding annular wall 83 freely surrounding the lower slotted end 84 of the down tube 69 and urged by the spring 80 into sealing relationship against said valve 78. Underthese conditions there is no flow communication between the cans 12 and 13.

However, when the spacer 16 is removed and the cans forced together in a manner later to be explained, the cans are then in a relationship, as shown in FIGURES 7 and 9, in which flow communication is established between the cans. Such relationship is brought about by virtue of the lower slotted end 84 of the tube 69 depressing the plug 81 against the spring 80 to compress the latter and to uncover vthe slots in the slotted end 84. In this down position of the plug 81, the valve 78 still seals the lower end of the tube 69 at' the valve opening 79, but flow between the cans is established through the exposed slots of said slotted end 84, around the Iplug 81 past the ribs 82 and through the opening provided by the spring 80 into the open upper end 85 of the down tube 73.

The valved dispensing mechanism of the upper can (FIG. is generally similar to that just described but differs therefrom in important respects. It includes a down-tube 86 secured at its outer end 87 to the inner end of a connector 88. The outer end 89 of said connector is outwardly flared for retention in a central housing 90 of the can closure 91 by an inwardly formed annular bead 92. A pair of resilient packing Washers 93 and 94 are held tightly within said housing 90 against the apertured end wall 95 thereof by the ared end 89 of the connector 88. In this arrangement said packing washers 93 and 94 close off the aperture 96 in said apertured end wall and also seal against the tube 69 that passes through said washers. The inner end (upper as shown in FIG. 1 0) of the tube 69 is provided with one or more openings 97, which is also sealed off (in the position shown) by said washer. The inner end of said tube 69 is closed inwardly of the openings 97 by the reduced end 98 of a plug 99. Said plug 99 is biased by a compression spring 100 in a downward direction, as shown in FIG. 10 to flex the packing washers 93 and 94 into the sealing relationship already described. Said plug 99 has radial ribs 101 providing passages past the plug for the flow of fluid when the openings 97 are uncovered. This occurs when the upper end lower cans 12 and 13 are forced into the position illustrated in FIGS. 7 and 9, as already described. It is believed unnecessary to show or describe the position of the various elements of the valved dispensing mechanism illustrated in FIG. 10 when fluid ow therethrough is established, other than to point out that during the act of forcing the cans together, relative upward movement of the plug 99 compresses the spring 100 and Aexposes the openings 97. Fuid flow can then take place from the tube 86 through the hollow body of the connector 88, through the passages provided by the plug ribs 101 past the plug 99 and through the then exposed openings 97 into the tube 69. v

When the two cans are in the position illustrated in FIGS. 7 and 9, therefore, full flow communication between the two cans 12 and 13 is established, so that if one of the cans, such as the can 12 is under a higher gas pressure than the can 13, the fluid contents of the can 12 will pass into the can 13 for admixture with the fluid contents of that can.

A further description will now be given of the manner of effecting a locking closure of the ends of the carton 11. In erecting the 'blank 17 into the form of carton 11, as previously stated, the side flaps 29 and 30 are suitably secured to the outer surface (as viewed in FIG. 2) of the panel 21 along and extending inwardly of the free edge 28, 28a thereof. With the 4carton in this position and its upper and lower ends open, one end is closed, such as the lower end, lby first turning in the end aps 48a and 46a about the line of fold 26 in either order. The Hap 47a is then folded inwardly and the tab 54a turned upwardly to abut against the inside of the panel 20. Thereafter the tab 49a is inserted into the slot 51a with which it is now aligned. The tab 49a thereupon effects a locking of the flap 47a to form the outer end closure wall. The assembled bottom closure can then not be opened up without considerable manual effort. While a high pressure of gas within the carton, after it has been closed, might effect a bulging of the end closures, it is unlikely'that the closures would Iblow open, since, of course, the carton even when closed is not gas-tight. After the insertion of the two cans in the manner previously described, the top end closure is effected in a manner exactly similar to that described for the lower end closure. The tab 49 by being inserted in the slit 51 serves to lock the end closing wall ap 47 against unintentionally coming open. With the door-forming flap 32 also closed, the carton is then in the form shown in FIG. l, ready for shipment or handling.

When it is desired to use the contents of the cans 12 and 13, the door-forming flap 32 is first opened (FIG. 5), and the spacer member 16 is withdrawn through the opening 65 provided for the purpose. The door-forming flap 32 is then again closed and the package is ready for mixing of the contents of the cans 12 and 13.

In order to provide for the collapsibility of the carton 11 endwise, during the operation of mixing the contents of the cans 12 and 13, the parallel score lines 42, 43 and 44 are traversed by slits 105, 106, 107 and 108 along the respective lines of fold 22, 23, 24 and 33. By reason of these slits, the narrow bands 109 and 110 left between the outer score lines 42 and 44, are free to flex inwardly or outwardly about the median score line 43, the flexing ordinarily being outwardly as illustrated in FIG. 7, where the bands of material 109 and 110 are shown inclined outwardly and convergently toward the score line 43. Thus the arrangement of the score lines 42, 43 and 44 and the intersecting slits 105, 106, 107 and 108, in cornbination with the opening 65 provided by removing the knock-out portion 39, make possible an accordion-like action of the side Walls of the container during the application of the endwise collapsing forces. Since the collapsing takes place with the door-forming flap 32 in closing position, this accordion-like action occurs simultaneously in each of the sidewalls 18, 19, 20 and 21, and also in the door panel 32, thereby insuring a truly axial, relative movement between the cooperating tube 69 of the upper can 12 and the valved dispensing mechanism of the lower can 13.

Actual mixing, then, is accomplished by applying a downward force to the upper closure including the end closure ap 47 with the carton vertical and resting against a solid foundation. A suiiicient force is applied to cause the dependent tube 69 of the upper can to move downwardly into the position illustrated in FIGS. 7 and 9, the downward movement being limited by the beaded edge 14 of the upper can resting against the beaded edge 15 of the lower can. With the cans in this position, as previously stated, uid ow is established between the cans. Transfer takes place from the can that is under a higher gas pressure to the can that is under a lower gas pressure.

By way of example, the upper can 12 may contain a propellant gas in liquefied form and a catalyst under, say, 80 p.s.i., and the other can may contain a prepolymer in a solvent under, say, 40 p.s.i. In this case, of course, the propellant gas and catalyst would ow under pressure into the lower can 13 containing the prepolymer and solvent. During such flow, the operator shakes the package as a unit for the length of time required, which may be several minutes. At the end of such time, not only has the transfer been effected, but there has been thorough mixing of the contents of the two cans with the result that the can containing the complete mixture is now ready for use.

To use the latter can, it is a simple matter to open up the carton and to remove such can and use it wherever the foam-in-place resin is to be applied. The resulting foamed resin is then allowed to expand to the extent desired, or to the extent permitted by the rformation of gas within the mass of the resin mix. Ordinarily a selfcuring resnous mix is used that requires no heat but only a certain length of time for the reaction to be completed. It is usually best to use up completely the contents of the can containing the complete mixture, since otherwise expansion of the contents of the can could take place that would make the contents unusable in any extent.

I yclaim as my invention:

1. A carton blank comprising side wall-forming panels having edge-forming lines of fold connecting adjacent panels, end closure-forming extensions of said panels having end edge-forming lines of fold between said extensions and the corresponding panels, certain of said extensions and panels having cooperating tabs and slits, an

outside one of said panels having spaced marginal extensions adapted to be joined to the other outside panel, said one outside panel having a transversely extending knock-out portion to form an opening terminating at one end between said marginal extensions and at the other end adjacent the nearest line of fold, said other outside panel having an integral door-forming flap foldable about a therebetween edge-forming line of fold to close said opening, said door-forming ap having locking tabs, all other panels than said one outside panel and said doorforming ap having a plurality of parallel lines of weakness aligned with said knock-out portion and extending completely across from said knock-out portion carrying panel to the free edge of said door-forming flap, there being slits along the edge-forming lines of fold extending across said lines of weakness and other slits in and adjacent. an end-edge-forming line of fold for receiving said locking tabs to hold said door-closing flap in openingclosing position.

2. A carton blank as defined by claim 1 wherein one end closure-forming extension on said one outside panel has a locking tab joined thereto by an end edge line of fold having a slit therein centrally of said line of fold, and a foldable tab is provided along a line of fold centrally of the corresponding end edge of the panel that forms an opposite side wall of the erected carton, said foldable tab 4being insertable into said last mentioned slit when said locking tab is tucked in behind said opposite side wall-forming panel in forming the corresponding end closure and locking the same closed. 3. A carton blank as dened by claim 2, wherein a second end closure-forming extension with locking tab is provided on the other end edge of said opposite side wall-forming panel identical to said one end closure With locking tab, and a second foldable tab identical with said rst mentioned foldable tab is provided on the corresponding end edge of said one outside panel for cooperation therewith in forming and locking the corresponding edge closure. 4. A carton blank as dened `by claim 1, wherein said certain end closure-forming extensions and panels having cooperating tabs and slits are identical but in end-for-end reversed relationship and are separated by an intervening side wall-forming panel. 5. A carton blank as defined by claim 4, wherein said intervening panel and the remaining side wallforming panel have end closure-forming extensions identical in outline with stepped edges that cooperate in the closing of said end closure-forming extensions to facilitate such closing and the locking thereof.

References Cited UNITED STATES PATENTS 6 LoUrs G. MANCENE, Primm Examiner,

Claims (1)

1. A CARTON BLANK COMPRISING SIDE WALL-FORMING PANELS HAVING EDGE-FORMING LINES OF FOLD CONNECTING ADJACENT PANELS, END CLOSURE-FORMING EXTENSIONS OF SAID PANELS HAVING END EDGE-FORMING LINES OF FOLD BETWEEN SIAD EXTENSIONS AND THE CORRESPONDING PANELS, CERTAIN OF SAID EXTENSIONS AND PANELS HAVING COOPERATING TABS AND SLITS, AN OUTSIDE ONE OF SAID PANELS HAVING SPACED MARGINAL EXTENSIONS ADAPTED TO BE JOINED TO THE OTHER OUTSIDE PANEL, SAID ONE OUTSIDE PANEL HAVING A TRANSVERSELY EXTENDING KNOCK-OUT PORTION TO FORM AN OPENING TERMINATING AT ONE END BETWEEN SAID MARGINAL EXTENSIONS AND AT THE OTHER END ADJACENT THE NEAREST LINE OF FOLD, SAID OTHER OUTSIDE PANEL HAVING AN INTEGRAL DOOR-FORMING FLAP FOLDABLE ABOUT A THEREBETWEN EDGE-FORMING LINE OF FOLD TO CLOSE SAID OPENING, SAID DOOR-FORMING FLAP HAVING LOCKING TABS, ALL

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