TRANSPARENT EGG CARTON

Abstract

The present invention provides an egg carton having a tray having a first row of a first plurality of spaced egg compartments and a second row of a second plurality of spaced egg compartments, the first row of egg compartments being disposed in parallel spaced relationship to the second row of egg compartments; a plurality of spaced tower elements extending along a centerline of the tray and extending vertically from a plane of the tray, each tower element having four egg contacting surfaces; a plurality of spaced post elements extending along a front edge of the tray and extending vertically from a plane of the tray, each post element having two egg contacting surfaces; and a lid hingedly connected along a rear edge of the tray and movable from an open condition to a closed condition.

Description

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention provides an egg carton and more particularly an egg carton of a transparent polymeric material.

2. Background of the Invention

Conventional egg cartons in wide use today are typically made either of a fibrous material, such as cardboard, or a foamed polymeric material, such as foamed polystyrene. While these materials are inexpensive to prepare they share the same disadvantage of being opaque, requiring a consumer to open the lid of the egg carton to inspect the eggs for damage.

Egg cartons made of a transparent polymeric materials, such as polyethylene terephthalate (PET) polymers have also come into use, although to a more limited extent than cardboard and foamed polystyrene cartons. Such transparent egg cartons exhibit various disadvantages that result from the properties of the materials used. For example, while these materials are recyclable, they are not biodegradable.

Transparent polymeric egg containers in the market today commonly have two lids in a trifold design. The first lid is conformed to fit over the top of the eggs, and the second lid is conformed to fit over the first lid. In another design, instead of using a flap, the lid and tray of the carton are configured with a series of snap locks around the rim. Another egg carton disclosed in U.S. Pat. No. 4,240,575 shows a locking flap and hinge at an obtuse angle so that the flap is situated in a partially closed position. However, this design does not eliminate the problem of bending of the egg carton when grasped from the end.

One observation of some transparent egg cartons is it is difficult for consumers to release the lid from the interlocking tabs and holes. In the cardboard or foamed polystyrene designs, the consumer typically pulls the front of the lid forward from the center to clear the holes from the tabs and rotates the lid upward to open the carton. However, if the flap and lid are made of typical transparent polymeric materials, which are more pliable than cardboard or foamed polystyrene, pulling the front surface of the lid forward from the middle creates a bow action that results in bowing of the middle of the flap outward and the lateral sides of the flap inward, making it difficult to release the lid from the button tabs on the flap. One method of overcoming this problem is exemplified by U.S. Pat. No. 4,463,894 where it is disclosed to make the lateral portions of the flap thicker than the central portion to reduce the bowing effect. A problem with this design is that more material is required to form the flap.

Commonly assigned U.S. Pat. No. 7,258,234 discloses a transparent egg carton having a tray, a lid and a flap hingedly connected to a front edge of the tray for securing the lid to the tray when in a closed condition. The '234 patent discloses an egg carton formed from transparent plastic material such as polylactic acid or other biodegradable polymers. The flap is made with lattice struts to increase the lateral strength of the flap and has three button tabs for interlocking the flap to the lid.

Accordingly there is a need in the art to provide transparent egg cartons that have the advantages of cardboard and foamed polystyrene egg cartons while lacking the disadvantages inherent to cartons made of transparent polymeric materials.

SUMMARY OF THE INVENTION

The present invention provides an egg carton having a tray having a first row of a first plurality of spaced egg compartments and a second row of a second plurality of spaced egg compartments, the first row of egg compartments being disposed in parallel spaced relationship to the second row of egg compartments; a plurality of spaced tower elements extending along a centerline of the tray and extending vertically from a plane of the tray, each tower element having four egg contacting surfaces; a plurality of spaced post elements extending along a front edge of the tray and extending vertically from a plane of the tray, each post element having two egg contacting surfaces; and a lid hingedly connected along a rear edge of the tray and movable from an open condition to a closed condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of an egg carton in an open condition;

FIG. 2 is a perspective view of the egg carton of FIG. 1 in a closed condition;

FIG. 3 is a top plan view of the egg carton of FIG. 1;

FIG. 4 is a side elevation view of the egg container of FIG. 1;

FIG. 5 is a bottom plan view of a tray of an egg carton;

FIG. 6 is a top plan view of a second embodiment of an egg carton;

FIG. 7a is a side elevation view in cut away of the second embodiment of the egg carton of FIG. 6 in a closed condition; and

FIG. 7b is a side elevation view in cut away of the second embodiment of the egg carton of FIG. 6 in an open condition.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.

Described herein are various features of a transparent egg carton 10, which is suitable for embodiments using a variety of transparent polymeric materials, including, but not limited to relatively pliable recyclable polymeric materials such as polyethylene terephthalate (PET), which is an amorphous polyester; clarified polypropylene (CPP), which is polypropylene containing nucleating agents to increase clarity; styrene butadiene copolymers (SBC) without impact modifiers; copolymer blends of SBC with crystalline polystyrene (cPS), which is commercially known as “K-Resin/Crystal™”, oriented polystyrene (OPS); polyvinyl chloride (PVC); styrene acrylonitrile polymer (SAN); polymethyl methacrylate (PMM) and copolymers thereof, commercially known as Plexiglas; and polycarbonate (PC). In advantageous embodiments, the features of the egg carton 10 are also suitable for a newer class of transparent polymeric materials that are recyclable and biodegradable. Examples of such polymeric materials include polylactic acid (PLA), polyglycolic acid (PGA) and polylactic acid-glycolic acid copolymers (PLGA). In a preferred form of the invention, the egg carton 10 is preferably made of PLA, PGA, or PLGA in commonly known polymeric processing techniques such as thermoforming, injection molding, vacuum forming or other techniques well known to those skilled in the art.

FIG. 1 shows a transparent egg carton 10 having a tray 12 and a lid 14 hingedly connected thereto for movement between and open condition (FIG. 1) to a closed condition (FIG. 2). The tray 10 has a generally rectangular peripheral wall 16 having a front edge 18 and a rear edge 20 defining an imaginary plane of the tray 22. The tray has a first row 24 of a plurality of egg compartments 26 and a second row 28 of a plurality of egg compartments 26 in parallel spaced relationship to the first row. While it is shown that each of the first and second rows of egg compartments have six compartments it is contemplated that each row could have from as little as two up to twelve or more compartments provided the container has sufficient physical properties to protect the eggs during shipment and handling by a user of the eggs. Each egg compartment 26 has a generally ovoid shaped wall 30 that extends downward below the plane of the tray 22 and is closed by an end wall 32. In one preferred form of the invention, the end wall has an inner surface 34 that extends concave upwardly. A plurality of circumferentially spaced and inwardly extending tabs 36 are deformed from the wall for engaging an outer surface of an egg. The tabs are generally rectangular shaped with rounded ends with the length dimension oriented parallel to an axis of the compartment. In a preferred form of the invention eight tabs are provided and are equally spaced about the circumference of the wall 30 of the compartment. The tabs contact the shell of an egg to reduce the surface area that the shell is in contact with the wall 30. By reducing the surface area contact between the wall and the egg shell reduces the tendency for the egg to stick to the wall of the compartment and to become damaged upon removal from the compartment.

FIGS. 1-3 show a plurality of tower elements 40 spaced horizontally along a centerline 42 of the tray and extending vertically upwardly above the plane of the tray by a first distance. Each tower element 40 has four egg contacting surfaces 44 one of each surface associated with a different egg compartment. The egg contacting surfaces 44 are concave to conform to a portion of an egg that extends above the plane of the tray. Each tower element 40 has a top end 46 that is generally circular and has a flat surface 48 for contacting a bottom surface of the lid 14 to protect the egg contents from crushing even upon stacking of other similar filled egg cartons on top of the lid. A notch 47 is provided along a wall connecting each adjacent tower element 40 to provide a vent for when eggs are inserted into each egg compartment.

A plurality of horizontally-spaced supports 50 are provided along the front edge 18 of the tray. The supports 50 extend above the plane 22 a second distance which is less than the first distance. Each of the supports 50 have two egg contacting surfaces 52 for contacting eggs in two adjacent egg compartments of the first row 24. The egg contacting surfaces 52 are generally concave to conform to the shape of an egg placed in the compartment. The supports 50 have the shape of a truncated equilateral triangle in horizontal cross-section dimension with a truncated apex 54 pointing inward of the container toward the tower elements 40. In a preferred form of the invention, two of the outermost supports, those closest to lateral edges 56 of the tray, have a tooth-shaped protuberance 58 extending outwardly of the container from an outer surface 60. The tooth-shaped protuberance 58 has an outwardly tapering and downwardly extending surface 62 defining a downwardly facing surface 64 with a laterally extending groove 66. The protuberance 58 is commonly known as a button tab and is for releasably engaging a button tab mating surface 68 on the lid 14, as will be discussed in greater detail below.

As seen in FIG. 1, the center support 70 is segmented with a lower section 72 and an upper section 74 connected by a tapering middle transition section 76. During closing of the lid, the transition section 76 engages a tab mating surface 68 of the lid and guides the lid into proper alignment for engagement of the lower section 72 with a button tab mating surface 68 on the lid.

A plurality of horizontally-spaced post elements 80 are positioned along the rear edge 20 of the tray each of which has two egg contacting surfaces 82 for contacting two eggs one of each in adjacent egg compartments of the second row of egg compartments 26. Each of the post elements 80 have the shape of a truncated equilateral triangle in horizontal cross-section dimension with a truncated apex 84 pointing inward of the container toward the tower elements 40. Each of the post elements 80 extend vertically upward above the plane 22 of the tray a third distance and terminate in a flat upper surface 86. The third distance is less than the second distance.

FIGS. 1 and 3 also show an optional feature of four corner tabs 90 that extend vertically above the plane 22 of the tray and each has an egg contacting surface 92 that is generally concave, a rear wall that is generally convex 94 and has a flat top surface 96. The corner tabs engage optional compartments in the lid to ensure proper alignment of the lid with the tray when in the closed condition and to resist inadvertent opening of the lid.

As best seen in FIGS. 5 and 6, a buttress 98 extends below the plane 22 of the tray and between each adjacent egg compartment to provide support along the longitudinal dimension of the tray. In a preferred form of the invention, the buttress extends from about 40% to about 90%, more preferably from about 45% to about 85% and most preferably from about 50% to about 80%, or any range or combination of ranges therein, as far as the end wall 32 extends from the plane 22. The buttress is generally U-shaped in vertical cross-section dimension and in a preferred form of the invention has an optional strut 100 that is generally arcuate shaped and extends upward into the tray and between two legs of the U-shaped buttress. The strut is to provide support along the latitudinal dimension of the carton.

FIGS. 1-5 show the generally rectangular shaped lid 14 having two horizontally spaced end walls 102, a front wall 104 and a rear wall 106 in parallel spaced relationship, all of which are vertically upstanding and are connected by a horizontally extending top wall 108. The front wall 104 has three button-tab mating surfaces 68. In another preferred form of the invention only the two outermost button tabs are provided; thus, the center button tab shown is optional. In one preferred form of the invention, the two outermost button-tab mating surfaces consist of a generally rectangular opening 110 through the entire thickness of the front wall. When the lid is in the closed condition, each of the tooth-shaped protuberances 58 extend through the opening 110 and a lateral edge of each tooth engages a vertically extending edge 112 of the opening and the groove 66 engages a bottom 114, horizontally extending edge of the opening to releasably engage the lid. The distance between the vertically extending edges 112 is about the same as the distance between the lateral edges of each tooth they engage to place the lid under lateral tension to resists inadvertent opening of the lid. The optional middle button-mating surface 68 is rectangular shaped indentation that is dimensioned to interlock with the lower section 72 of the center support 70 when the lid is in the closed condition (FIG. 2). It should be understood that the button-mating surfaces described above are interchangeable and any combination of the same could be used.

At each of the corners 116 of the lid are optional arcuate shaped pockets 118 having a bottom wall 120 for engaging the corner tabs 90 of the tray. FIG. 3 also shows several optional strengthening indentations 120 deformed from the top wall 108 of the lid—two optional longitudinally extending indents 122 in registration with a centerline drawn through the centers of the first and second rows of egg compartments 24,26 and four optional lattitudinally extending indents 126 forming a line between adjacent tower elements 40. Vertically extending indents 126 are also provided on the lid front and rear walls 104,106 in alignment respectively with the supports 50 and the post elements 80. The lateral end walls of the lid each have two raised areas 129 that are in registration with raised areas 130 on the tray lateral walls to form vents that are in alignment with the center of the first and second row of egg compartments.

The lid rear wall 106 is hingedly connected to the rear edge of the tray 20 with a W-shaped hinge or a box hinge 131 as set forth in U.S. Pat. No. 7,258,234 which is incorporated herein by reference and made a part hereof.

FIGS. 6, 7a,b show another preferred form of the invention that differs from the embodiment shown in FIGS. 1-5 by the provision of a gutter 132 that extends from the front edge of the tray 18 and is dimensioned to releasably interlock with a tab 134 extending from the lid front wall 104. The gutter and tab have complementary shapes such as concave and convex for the parts to fit together and form an interference fit. Also provided on the front edge of the tray 18 is a finger recessed area 136 generally centrally located thereon.

One advantage of the present invention is that the transparent, polymeric egg carton has no flap extending from the front edge of the tray. This provides significant savings in terms of material used without diminishing the desirable physical properties of the carton and its ease of use by consumers.

From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims

Claims

1. An egg carton comprising:

a tray having a first row of a first plurality of spaced egg compartments and a second row of a second plurality of spaced egg compartments, the first row of egg compartments being disposed in parallel spaced relationship to the second row of egg compartments;

a plurality of spaced tower elements extending along a centerline of the tray and extending vertically from a plane of the tray, each tower element having four egg contacting surfaces;

a plurality of spaced post elements extending along a front edge of the tray and extending vertically from a plane of the tray, each post element having two egg contacting surfaces; and

a lid hingedly connected along a rear edge of the tray and movable from an open condition to a closed condition.

2. The egg carton of claim 1 wherein each of the plurality of post elements is aligned with each of the plurality of tower elements.

3. The egg carton of claim 1 wherein the first plurality of egg compartments and the second plurality of egg compartments comprises at least two egg compartments.

4. The egg carton of claim 1 wherein the post elements are positioned between adjacent egg compartments of the first plurality of egg compartments.

5. The egg carton of claim 1 wherein one of each of the two egg contacting surfaces of the post elements form a portion of each of two adjacent egg compartments.

6. The egg carton of claim 1 further comprising a first button tab on a first post element and a first mating button surface on the lid, wherein when the egg carton is in the closed condition the first button tab is positioned in the first mating button surface to releasably interlock the lid to the tray.

7. The egg carton of claim 6 wherein the first mating button surface is an indentation in the lid or a through hole in the lid.

8. The egg carton of claim 6 further comprising a second button tab on a second post element and a second mating button surface on the lid spaced from the first mating button surface, wherein when the egg carton is in the closed condition the second button tab is positioned in the second button surface to releasably interlock the lid to the tray.

9. The egg carton of claim 8 wherein the second mating button surface is an indentation in the lid or a through hole in the lid.

10. The egg carton of claim 8 further comprising a third button tab on a third post element positioned between the first post element and the second post element and a third mating button surface on the lid positioned between the first mating button surface and the second mating button surface and wherein when the egg carton is in the closed condition the third button tab is positioned in the third mating button surface.

11. The egg carton of claim 8 wherein the first button tab comprises a flange extending outwardly from a portion of the first post element and having a downwardly facing surface.

12. The egg carton of claim 11 wherein the downwardly facing surface has a groove dimensioned to releasably retain the first mating tab surface.

13. The egg carton of claim 1 further comprising a plurality of spaced supports positioned along a rear edge of the tray that extend vertically from a plane of the tray.

14. The egg carton of claim 13 wherein each support of the plurality of supports have two egg contacting surfaces.

15. The egg carton of claim 13 wherein one of each of the plurality of supports is in alignment with one of each of the plurality of tower elements.

16. The egg carton of claim 13 wherein the supports are positioned between two adjacent egg compartments of the second plurality of egg compartments.

17. The egg carton of claim 13 wherein the tower elements extend a first vertical distance from a plane of the tray, the post elements extend a second vertical distance from the plane and the supports extend a third vertical distance wherein the first vertical distance is greater than the second vertical distance and the third vertical distance.

18. The egg carton of claim 17 wherein the second vertical distance is greater than the third vertical distance.

19. The egg carton of claim 1 further comprising a gutter extending from the front edge of the tray and dimensioned to releasably retain a portion of the lid when in the closed condition.