Tapered tray with pre-glued elevating legs

• US 4,871,111 A
• Filed: 04/20/1988
• Issued: 10/03/1989
• Est. Priority Date: 04/20/1988
• Status: Expired due to Fees

• Current Assignee: Waldorf Corp
• Original Assignee: Waldorf Corp
• Inventors: Mode, Duane R.
• Primary Examiner(s): Elkins, Gary
• Application Number:
  US07/183,971
• Time in Patent Office: 531 Days
• Field of Search: 426/107, 426/113, 426/234, 426/243, 219/10.55 E, 229/104, 229/112, 229/171, 229/182, 229/3.5 MF, 229/903
• US Class Current: 229/104
• CPC Class Codes: B65D 2581/3406 Pizza or bread
• CPC Class Codes: B65D 2581/3441 3-D geometry or shape factors, e.g. depth-wise
• CPC Class Codes: B65D 2581/3494 Microwave susceptor B65D2581/3487 takes precedence
• CPC Class Codes: B65D 5/2047 trapezoidal, e.g. to form a body with diverging side walls B65D5/2033 takes precedence
• CPC Class Codes: B65D 5/302 combined with a slot provided in an adjacent side wall
• CPC Class Codes: B65D 5/42 Details of containers or of foldable or erectable container blanks
• CPC Class Codes: B65D 81/3453 Rigid containers, e.g. trays, bottles, boxes, cups
• CPC Class Codes: Y10S 229/903 Ovenable, i.e. disclosed to be placed in an oven

Abstract

A package for holding food for cooking in a microwave oven has a flat central panel for supporting the food, which has at least three linear panel edges. A flat side wall is attached at a fold line to at least two of the panel edges of the central panel. Each side wall has an inner panel and an outer panel affixed against the inner panel. The outer panel has a maximum width as measured perpendicular to the fold line connecting the side wall to the central panel that is greater than the width of the inner panel, also measured perpendicular to the fold line. The invention also encompasses a flat blank that can be folded and locked or glued into the preceding package configuration. For microwave oven use, the blank is made from paperboard material having a layer of microwave interactive material that heats to browning temperatures when exposed to microwaves.

Claims

1. A collapsible package for holding food comprising:

a substantially flat central panel for supporting said food, said panel having first and second pairs of opposed, substantially linear panel edges and four corners; and

first and second substantially flat side walls, each of said side walls being attached to one of said first pair of opposed central panel edges at an inner fold line substantially coinciding with said central panel edge, each said side wall being disposed at approximately 90 degrees relative to said central panel, and comprising;

an inner panel extending above the plane of said central panel;

an outer panel joined to said inner panel at an outer fold line substantially parallel to said inner fold line and adhered against said inner panel to form a double layer above the plane of said central panel, said outer panel having a maximum width, as measured perpendicular to said inner fold line, that is greater than the width of said inner panel measured perpendicular to said inner fold line, said outer panel extending in a single layer below the plane of said central panel to the extent of said greater width;

a pair of opposed end walls, each attached to said central panel at one end fold line located at one of the second pair of opposed edges of said central panel; and

hook and slit locking means adjacent each corner of the central panel for locking together adjacent side walls and end walls to maintain said side walls disposed at approximately 90 degrees relative to said central panel.

2. The package as recited in claim 1 wherein the package is for cooking food in a microwave oven and at least a substantial portion of the surface area of said central panel comprises a microwave interactive material that heats up to a temperature sufficient to heat the surface of food in heat transfer relationship with said central panel when said central panel is exposed to microwaves.

3. The package as recited in claim 2 wherein at least a substantial portion of the surface of the inner panel of each side wall comprises a microwave interactive material that heats up to a temperature sufficient to heat the surface of food in heat transfer relationship with each said inner panel when each said inner panel is exposed to microwaves.

4. The package as recited in claim 1 wherein the package is for cooking food in a microwave oven and is made from paperboard to which a thinly metallized plastic film is laminated with the metal layer being sandwiched between the paperboard and plastic film.

5. The package as recited in claim 4 wherein the maximum width of said outer panel exceeds the width of said inner panel by about one-fourth of the primary wavelength utilized in said microwave oven.

6. The package as recited in claim 4 wherein the plastic film is selectively metallized so that the metal layer does not extend to substantial portions of said outer panel.

7. The package as recited in claim 1 wherein each side wall is disposed so that the included angle between the side wall and the central panel is slightly greater than 90 degrees.

8. The package as recited in claim 1 wherein said central panel is rectangular in shape.

9. The package as recited in claim 8 wherein said opposed end walls are attached to said central panel at end fold lines perpendicular to said inner fold lines, said end walls being disposed at approximately 90 degrees relative to said central panel.

10. A flat blank for forming an elevated tray for holding food comprising:

a substantially rectangular central panel for supporting said food having a first pair of opposed, parallel linear panel edges;

first and second side walls, each of said side walls being attached to one of said first pair of opposed, parallel central panel edges, each said side wall comprising;

an inner panel adapted to extend above said central panel and having an inner edge joined to the central panel at an inner fold line;

an outer panel joined to said inner panel at an outer fold line substantially parallel to said inner fold line and adapted to extend downward from said outer fold line and below said central panel, each said outer panel having a maximum width as measured perpendicular to said outer fold line that is greater than the width of said inner panel measured between said inner and outer fold lines wherein each inner panel of each side wall has a pair of opposed locking tabs attached to opposed edges at locking tab fold lines that are perpendicular to said inner fold lines and each end flap has a pair of slits therein designated to receive a portion of the adjacent locking tab when the end flaps and side walls are raised to form sides of said tray.

11. The flat blank as recited in claim 10 wherein the flat blank is adapted to form a package for cooking food in a microwave oven and is made from paperboard to which a thinly metallized plastic film is laminated with the metal layer being sandwiched between the paperboard and plastic film.

12. The flat blank as recited in claim 11 wherein the maximum width of said outer panel exceeds the width of said inner panel by about one-fourth of the primary wavelength utilized in said microwave oven.

13. The flat blank as recited in claim 10 wherein said inner and outer panels of said side walls are rectangular and of approximately the same size and shape, except that each said outer panel has at least one projection thereon whose width measured in a direction perpendicular to said outer fold line is approximately one-fourth of the primary wavelength utilized in said microwave oven.

14. The flat blank as recited in claim 10 wherein each outer panel of each side wall is folded 180 degrees at said outer fold line to lie under its adjacent inner panel and is adhered to said inner panel so that each side wall is of double thickness between said inner and outer fold lines and a portion of each outer panel extends under said central panel.

15. The flat blank as recited in claim 14 wherein each outer panel has two projections thereon, one being located at each end of an edge of said outer panel located opposite said outer fold line.

16. The flat blank as recited in claim 10 wherein the tray is for cooking food in a microwave oven and at least a substantial portion of the surface area of said central panel comprises a microwave interactive material that heats up to a temperature sufficient to heat the surface of food in heat transfer relationship with said central panel when said central panel is exposed to microwaves.