CA1153216A

CA1153216A - Tray container with reinforced sidewalls

Info

Publication number: CA1153216A
Application number: CA000377046A
Authority: CA
Inventors: Guelfo A. Manizza; William M. Brown
Original assignee: Federal Paper Board Co Inc
Current assignee: Federal Paper Board Co Inc
Priority date: 1980-05-12
Filing date: 1981-05-07
Publication date: 1983-09-06
Also published as: AU7022481A; SE8102873L; DK208881A; DE3169162D1; EP0039939B1; EP0039939A1

Abstract

TRAY CONTAINER WITH REINFORCED SIDEWALLS
Abstract of the Disclosure A tray-type container for processing and marketing a loaf of bread, or the like, and a method of forming the same is disclosed, which tray is formed from a single blank of paperboard having a coating of a heat sealable and heat resistant film material so as to provide, when fully set-up, a rectangular bottom wall with hingedly connected upstanding sidewalls integrally connected at the corners by pairs of triangular web members folded upon each other and against the outside faces of opposite sidewalls where they are secured in reinforcing relation by narrow top edge flanges folded into underlying relation with and sealed to narrow flanges at the top edge of the sidewalls with the film material being skip-cut at the top edge of the sidewalls so as to reduce buckling in the sidewalls which otherwise results due to the difference in shrinkage of the film and the paperboard material.

Description

~S32~6 TRAY CONTAINER WITH REINFORCED SIDET~ALLS
Background of the Invention -This invention relates to containers and is more particularly concerned with improvements in product containers which are in the form of a tray and which are adapted to be fabricated from paperboard or similar foldable sheet material of a character which will enable the container to be used for baking bread, or ht elike, and marketing the product in the tray in which it has been baked.
The invention also relates to an improved cover for the container, and in particular, to a tear-out type cover which will serve to permit the major portion of the cover to be torn off while leaving most or all of the marginal of the cover or lid member in tact and secured to the top tray flange in reinforcing relation.
Tray containers have been developed heretofore which are particularly adapted for use in the bakery industry where the product may be processed in an oven and subsequenlty mar-k~ted without removing it from the container in which it has been processed. Products such as cakesl pastry, and the like are generally in a flowable state initially, that is, in a liquid or semi-liquid condition, and it is a requirement that the con-tainer be leakproof when filled to a predetermined level with ~ the product and capable of withstanding oven temperatures i during the baking process without damage from the heat so that the baked product may be marketed without removal from the container. For such products, containers have been developed ., . ' ,.

~ 1~532~6 which are adapted to be formed from thin metal foil or relatively stiff metallic sheet material which can be pressed or shaped to the desired form and become part of the final ~
package in which the product is marketed. Such containers are generally expensive and lacking in esthetic appeal since they do not readily accept the inks commonly employed in decorative printing. Efforts have been made, with some degree of success, to provide non-metallic trays which are suitable for this purpose. One such tray structure is disclosed in U.S. Patent No~ 4,114,797 granted September 19, 1~78. Trays of this type, which are formed from paperboard having a film-like heat resistant coa~ing, have not been entirely satisfactory for handling some bakery products, such as bread, where a rectangular shape is desired so that the finished product will have the conventional rectangualr shape of a loaf of bread.
The plastic film employed for trays of this type generally has shrink characteristics which differ from paperboard with the result that the sidewalls buckle and have an unattractive appearance.
20~ Consequently, there appears to be a need for trays of this type which have greater rigidity or stiffness, particular-ly in the sidewall panels so as to more nearly retain their shape during processing and which may be employed for pro-cessing in a microwave oven as well as in a conventional convection oven.
It is a general object, therefore, of the present invention to provide an improved open top tray structure of the type described which has greater rigidity in the sidewalls, which is more versatile in use, and more economical so as to compete with trays formed of metal foil, and the like.

~ I

1~53Z16 It is a more specific o~ject cf the invention to provide an improved tray structure and a method of forming the same in which the tray is fabricated from a paperboard blank coated with a film forming heat resistant plastic material which is cut and scored, so that it can be set-up with sidewall panels upstanding from a rectangular bottom wall panel and connected at the corners by pairs of integral web members which are folded upon each other and against the out-side faces of oppositely disposed sidewalls having narrow top flanges for reinforcing the sidewalls and with provision for anchoring the folded web members in position and having over-lapping tab members forming corner connections between the top edge flanges.
It is a further object of the invention to provide a tray structure of the type described and a method of :fabricating the same so as to provide integrally hinged top flange forming strLp members on the sidewalls, with cut scoring at~the hinge connection between the sidewalls and the top flanges which will prevent the difference in the contraation and expansion characteristics of the plastic film and the paper-board from buckling the sidewalls during processing of the tray and product in a baking oven.
A still further object of the invention is to provide an improved lid or cover structure and method of securing the same to the top edge flange of the tray or like container referred to above, with the cover or lid structure be arranged to have the major portion thereof torn out so as to expose the contents of the tray, while leaving the remaining or _ 3 _ . I`

1153~16 marginal portions of the cover in tact and secured to the top flange of the try so as to reinforce the sidewalls of the tray~ ~
A still further object is to provide a cover member which is cut scored on opposite faces adjacent its outer margins so that the marginal strip surrounding the center panel will remain adhered to the top surface of the tray flange for stiffening purposes when the center panel of the lid is torn out.
The herein disclosed and claimed invention comprises a tray structure and a method of forming the same from a cut and scored blank of foldable paperboard which is coated with a heat resistant plastic film, which tray comprises a bottom wall forming panel and oppositely disposed pairs of peripheral side-wall forming panels which are integrally hinged to and disposed in upstanding relation with the bottom wall forming panel, with pairs of integrally hinged triangular web members at the inter-secting corners, which web members are folded into overlying relation on the outside face of oppositely disposed sidewall panels and secured in position by means of a top edge flange formation adhesively adhered beneath an edge reinforcing strip in the form of a flange which is integrally hinged to the top edge of the associated sidewall forming panel on a hinge line defined by cut-scores in which the plastic film is severed by closely spaced small length cuts.
The invention further comprises a cover for the tray, which cover includes an outer margin and a central panel design by a cut or score line, with the margins of the cover being adhesively attached to the top flange of the tray and with the center cover panel being thereby adapted to be torn _~_ .

.1~, 1 1:153216 out to expose the tray contents while leaving the cover margins adhesively secured to tlhe tray flange for reinforcing the tray flange and sidewalls.

BRIEF DESCRIPTION OF TH~ DRAWINGS

FIG. 1 is a perspective view of a tray-type container which embodies the principal features of the invention; the tray beiny shown with a top covering member in place; .

FIG. 2 is an elevational view of the one side of the tray container shown in FIG. l;
.
FIG. 3 is a plan view of the tray o FIG. 1 with the top covering member removed;
,.
FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 2 to an enlarged scale;

FIG. 5 is a fragmçntary cross-sectional view taken on the line 5-5 of FIG. 2, to a greatly enlarged scale and with portions broken away;

:;
; FIG. 6 is a plan view, showing the inside face of a blank which is cut and scored preparatory to the forming of the tray shown in FIG. l;

~1..

FIG. 7 is a perspective view of the tray with the improved cover or lid;

FIG. 8 is a plan view with portions broken away showing the cover in place atop the tray;

FIG. 9 is a plan view similar to that of FIG. 8, but showing a portion of the novel cover being torn away;

FIG. 10 is a view of the tray of FIGS. 7-9, showing the same with the cover center panel being removed and with the outer margins of the cover remaining in place atop the upper tray flange:

FIG. 11 is a vertical sectional vlew on an enlarged ~: scale taken along lines 11-11 of FIG. 8 and showing the outer margins of the tray, and the lid, including the score lines separating the cover center panel from the margins of the cover;

FIG. 12 is a vertical sectional view of a portion of :~ the tray of FIG. 10 with the cover center panel removed and ~ the margin remaining in place;
~ ' FIG. 13 is a fragmentary top plan view of an alternate form of the cover made according to the invention; and ':
: FIG. 14 is a fragmentary top plan view of the form of .
cover or lid shown in FIG. 13 and showing the lid in the process of being removed from its associated tray.

. - 6 -. .

DESCRIPTION OF THE PREFERRED
EMBODIMENT OF THE :INV`ENTION

Referring now to the drawings in greater detail, there is illustrated a tray-type container or carton lQ which is adapted for use in the preparation and marketing of bakery pro-ducts, particularly, bread; the tray structure being fabricated from a single sheet of flexible paperboard material which is coated with a heat resistant film and which is cut and scored as illustrated in FIG. 6. It will be understood that the container shown in the drawings is described and illustrated for the purpose of setting forth the presently preferred fo~m of the invention and that the principles of the invent~on may be otherwise applied.
The tray 10, as illustrated in FI-GS~ 1 to 5, is ; fabricated from the cut and scored blank 12 which is shown in FIG. 6 with the face uppermost which will become the inside face in the set-up tray~ In the form illustrated, the blank 12 is prepared ~rom paperboard~ of relatively light weight or ~auge, which is coated or laminated with a suitable material to render it more resistant to damage ~hen subject to high tem-peratures, particularlv bakin~ oven temperatures. The paper-board stock is of a gauge which will provide a predetermined degree of stiffness, so that, the fully formed tray or carton will retain its normal s~ape when filled with the product for processing. The illustrated material is provided with a coating of plastlc film material which will increase its re-sista e to absorption of heat to the degree des~:red for 1153~16 withstanding baking oven temperatures and which will also permit heat sealing of the coated surface to the paperboard surface. A suitable treatment of paperboard stock to ~orm the blank 12 is set forth in U. S. Patent No. 3,904,104 granted September 9, 1976 to William Paul Xane.
The blank 12, which is particularly designed to form a tray for processing a loaf of bread, that is, having a some-what greater length than width, is in the form of a generally rectangular sheet of the foldable material with a substantially greater length than width. The blank is cut so thatithe grain is in the direction of the width or shortest dimension of the blank, as indicated by the arrow 13 in FIG. 6. The blank is cut and scored or creased, so that it is symmetrical about longitudinal and transverse center lines a-a and b-b. The blank is divided by parallel longitudinally extending, trans-versely spaced, hinge forming score or crease lines 14, 15 ; and parallel transversely extending, longitudinally spaced, ; hlnge forming score or crease lines 16, 17 which define a bottom wall forming center panel 18 with its edges coinaiding with the bottom edges of sidewall forming panel portions 20 and 22, and end wall ~orming panel portions 23 and 24. The side and end wall panel portions 20, 22 and 23, 24 are con-~; nected at the four corners of the blank by corner connecting web portions 25, 26, 27, and 28. The transverse score lines 16 and 17 are extended at their opposite ends on lines 30, 32 33 and 34, respectively, the latter being on a slight angle or inclination in the direction o the opposite ends of the 1:.
liS32~6 blank and defining the opposite ends of the sidewall panels 35and 36. The sidewall panels 35 and 36 have relatively narrow flange forming edge reinforcing panel portions 37, 38 which extend along the free outer margins thereof and which are divided therefrom by combination cut and creased lines 40 and 42, the latter being parallel with and spaced outwardly of the score lines 14 and 15, respectively. The longitudinal score lines 14 and 15 are extended at their opposite ends on lines 43, 44 and 45, 46 which are at a slight angle or inclination in the direction of the opposite sides of the blank and which define the ends of end wall panels 47 and 48. The end wall panels 47 and 48 have outboard margins with relatively narrow edge reinforcing panel portions 50 and 52 which are divided therefrom by combination cut and creased lines 53 and 54, the latter being parallel with and spaced outwardly of the score :
lines 16 and 17, respectively. The corner connecting web . panels 25, 26, 27, 28 are each divided by a center fold ~orming score line 55, 56, 57, 58 so as to form pairs of triangular web panels 60, 62: 63, 64: 65, 66 and 67, 68~ The pair of web panels 60, 62 connect side and end wall panels 35 and 47 while the panels 63, 64 connect side and end wall panels 36, 47, ; : at one end of the blank, At the other end of the blank panels 65, 66 connect side and end wall panels 35 and 48 while panels 67, 68 connect side and end wall panels 36 and 48. The out:side edges 70, 72, 73, 74 of the corner web panels 6a, 64, 65, 68 are cut on lines which are approximatle~ normal to the score linec _ g_ , Il O, 32, 33, 34 and define the ends of the a=sociated sidewall panels 35 and 36 so that each pair of these corner web panels may be folded into overlying relation and positioned along the outside faces of the associated sidewall panels 35, 36 with the top edge of each triangular web panel positioned only a small distance below the top edge of the side wall 35, 36.
The co rner web panels 62, 63 and 66, 67, which adjoin the end wall forming panels 47 and 48, have narrow edge flange forming panel portions 75, 76 and 77, 78 which are divided therefrom by combination cut and scored lines 80, 82 and 83, 84. The panel portions 75, 76, and 77, 78 will have a width somewhat less than the width of the associated flange forming panels 37, 38 and 50, 52 which permits these panels to be engaged beneath the opposite ends of the associated top flange forming panels 37, 38 on the sidewall forming panels 35 and 36 when the corner web panels are folded into overlying relation with and along the top outside margin of the associated sidewall panels 35 and 36. The flange forming panels 75, 76 and 77, 78 are cut at the ends adjoining panels 50 and 52 on lines 85, 86 and 87, 88 so as to leave these panels, 50 and 52, with small tabs 90, 92 and 93, 94 extending from opposite ends thereof.
The flange forming panels 37 and 38 on the long length ~idewall forming panels 35 and 36 are each extended at their opposite ends to provide integral corner connecting tabs 95 and 96 on the flange panel 37 and tabs 97 and 98 on the flange panel 38.
The tabs 95, 96 and 97, 98 extend beyond transverse hinge fold lines 30, 32 and 33, 34 and are cut so as to overlie the end ` 1 1 53Z16 t s 90, 92 and 93, 94 on the end flange mem~ers 50 and 52 when the tray is set up (FIGS. 2, 3, 4).
The combination cut and scored lines 40, 42 and 53, 54 and 80, 82, 83, 84 are formed by "skip cutting" or "cut scoring" the blank material, that is, by cutting on these lines closely spaced cuts of relatively small length which extend through the plastic film coating 100 (FIG. 5) but not through the paperboard with which the film forms a laminate .
for a purpose hereinafter set forth. The intervals between the small lengths cuts may or may not be creased, since the cuts will define the hinge fold line for the relatively light gauge paperboard as well as a means for relieving the tension in the -film. The cut scoring on the lines 80, 82 and 83, 84 may be .
performed on the outside face of the blank, that is, the face opposite the film 100 and the cuts may extend through the paper-board 102 and the film 100.
In setting up the tray 10 from the blank 12, the end wall panels 47 and 48 may be folded on the hinge lines 16 and 17 simultaneously with the folding of the sidewall panels 35 and 36 about the hinge lines 14 and 15. The corner connecting web structures 25, 26, and 27, 28 will fold with the end and sidewall panels with which they are integrally connected and the two halves of each such corner structure will fold upon them-selves and about the hinge lines 30, 33 and 32, 34 with the folded panels being directed into overlying relation on the outside faces of the sidewall panels 35 and 36, leaving the small flange forming panels 75, 77 and 76, 78 with the coated or `~i ilS3216 o film side or face exposed for heat sealing to the outside faces of the end portions of the flange forming panels 37, 38 -on the sidewalls 35, 36. The end wall flange portions 50 and 52 will be folded into outwardly directed flange position followed by folding of the flange portions 37, 38 so as to bring the flange end tabs 95, 96, 97, 98 and 90, 92, 93, 94 into overlying sealed relation.
In FIG. 5, the purpose in forming the cut scoring of the material on the lines 40, 42, and 53, 54 is illustrated.
The plastic film material 100 and the paperboard material have sufficiently different shrinking and stretching characteristics when heated and cooled so that the sidewalls otherwise may be buckled due to this difference. This is undesirable. The cut scoring relieves or counteracts this to a substantial degree, so that the corner connecting web arrangement and the sidewall top flange formation is effective to prevent any substantial ~; ~)wing in the associated sidewalls.
One form of separate cover member or lid is shown at 105 in FIG. 1. This cover 105 may be provided which may be applied with its margins adhesively secured to the flanges 37, 38, and 50, 52 so as to seal the contents in the tray. To facilitate removal of the lid by the consumer r a corner flange tab, for example, 96, may be cut or weakened, on the line 106, to enable the associated corner of the lid to be more firmly grasped and more easily torn loose so as to start the separation of the lid margins from the sidewall flanges.
~:

ll 1~5321S

Referring now to FIGS . 7-14, an improved form of lid or cover which is particularly adapted for use with the tray 10 is shown. FIG. 7 shows the novel cover to be generally designated 110 and to include among its principal elements, a center cover panel 112, an outer margin 114 separat~d from the cover panel 112 by an exterior or upwardly extending score line 116 and an inner or downwardly directed score line 118.
As is shown in F:IG. 11, the tray 10 includes the plastic film material 100 adhesively secured to and overlying the paperboard 102. The composite material is formed into tray elements which include a sidewall panel 36 and a flange forming portion 38.
According to the invention, the outer margin 114 is also com-posed of a paperboard portion 120 and a plastic film portion 122. Furthermore, the slit 116 which separates the center panel 112 of the cover 110 from the margins 114 extends only through the paperboard and terminates above a part of the flange 38.
The other means serving to separate the outer margin 114 from the cover panel 112 is~the inner cut or score 118, which extends only through the plastic film 122 and terminates adjacent the junction of the sidewall 36 and the flange 38. Consequently, the line of weakness separating the center panel 112 from the margins 114 includes a pair of cut lines which are offset slightly from each other.
In use, when it is desired to open the container by separating the top 110 from the tray lOA, a finger tab 124 (FIG. 8) which is designed in part by cut lines 126, 128 is grasped and pull upwardly. As shown in FIG. 9, the center panel 112 may be pulled upwardly, with separation taking place along the score lines 116-118, permitting the cover to be removed. As shown in FIG. 10, when the cover is removed by 13l~i~2~6 outer margin 114 of the cover remains atop the tray flange 38 -serving to reinforce the same, while a margin 130 of plastic film 122 remains adhered to its counterpart 100 (FIG. 12).
By providing the offset or space between score lines 116 and 118, an air tight package may be provided, while desirable separation of the cover center panel from the remainder of the panel 110 may be achieved.
FIG. 13 and 14 show a modified from of cover generally designated 130 which includes a center panel 132, an outer margin 134, and outer and inner score lines 136, 138. The only difference in these constructions is that, in the embodiments of FIGS. 13 and 14, a tear tab assembly 140 is provided which includes parallel, spaced apart outer and inner score lines 142, 144. The tear tab 140 is spaced just inwardly of the corner of the cover 132.
In use, the tab 140 is pulled or pried upwardly where it readily separates along line 142. The cut line 144 on the inner surface permits separation of the tab from the remainder of the cover panel when a force i9 applied and the cover may be peeled back as shown in FIG. 14. This con-struction insures that an entire, uninterrupted outer margin may be provided and sealed.
It will thus be seen that the improved cover assembly utilizing the offset or spaced apart parallel score lines pro-vides a good seal, easy separation characteristics and insures that a substantial margin of a composite, paperboard and plastic film margin will remain affixed to the tray flange to add stiffening support thereto.
.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A container in the form of a tray for processing and packaging a loaf of bread or similar bakery product, said tray being formed from a single sheet of paperboard having a heat sealable and heat resistant film coating with a greater heat shrinkage coefficient than the paperboard material, said tray comprising a bottom wall panel, integral upstanding sidewall panels, folded triangular webs joining the ends of adjacent sidewall panels, with pairs of said webs secured to the outside faces of oppositely disposed sidewall panels, said sidewall panels having outwardly di-rected narrow flange formations at the top edges thereof and said connecting triangular webs having a top flange formation adhesively secured to the bottom face of the top edge flange formation on the sidewall to which said tri-angular webs are secured and said sidewall panels having a line of skip-cutting at the top hinge edge thereof with the cuts severing the film material but not through the paperboard so as to reduce buckling in the sidewalls which would otherwise occur due to the difference in shrinkage of the film and the paperboard material when the tray is heated and allowed to cool.

2. A container in the form of a tray as set forth in claim 1 wherein the tray has substantially greater length than width and the webs of each pair thereof are disposed on opposite ends and on outside faces of the sidewall panels which extend lengthwise of the tray.

3. A container in the form of a tray as set forth in claim 2 wherein the tray is formed with the grain of the material extending transversely of the bottom and sidewall panels.

4. A container in the form of a tray as set forth in claim 1 wherein the folded triangular webs of each pair thereof are heat sealed.

5. A container in the form of a tray as set forth in claim 1 wherein the triangular webs extend the full depth of the tray at the corners and said webs are folded and heat sealed so as to form a rigid corner post formation.

6. A cut and scored blank of paperboard material, for forming a container as claimed in claim 1, which is coated with a plastic film having greater shrink charac-teristics than the paperboard, said blank being divided on longitudinally and transversely extending pairs of spaced parallel hinge score lines so as to provide an elongate rectangular center panel constituting a bottom wall forming panel for a tray container, and pairs of side and end wall forming panels, extending about the perimeter of said cen-ter panel, the corners of said blank being scored so as to form pairs of triangular corner connecting web panels, each pair of which is adapted to be folded upon itself and against the outside face of the longer sidewall forming panel from which it is separated by a hinge score line and narrow flange forming strip portions at the outermost mar-gins of said side and end wall forming panels which are divided from said wall forming panels by skip cutting lines which penetrate the film coating material but not through the paperboard so as to minimize buckling in the wall form-ing panels which would otherwise occur upon oven processing due to the difference in shrink characteristics of the film and the paperboard.