Carton Latch Construction

Abstract

There is disclosed a carton made of foamed polystyrene or like material comprising a top portion and a bottom portion hinged along one side and releasably fastened along the other side by a plurality of latching means. An edge of the bottom portion of the carton having cells for receiving eggs or the like, is molded with a plurality of vertical protrusions along it, each protrusion having an outwardly projecting hook at its upper end. The hook is disposed inwardly of the carton edge and a cutout is made in the edge below the hook. Catches are molded in the corresponding edge of the carton lid, including inwardly extending detents to engage the hooks firmly when closed, and downwardly extending lips to engage the cutouts in the bottom portion edge. The latch means do not extend beyond the edges of the carton and effectively resist accidental opening when twisted.

Description

BACKGROUND OF THE INVENTION

In patent applications Ser. No. 789,856 for "Egg Carton" filed Jan. 8, 1969, by McKenna et al. and Ser. No. 808,621for "Egg Carton Hinge and Latch Construction" filed Mar. 18, 1969, by Fred P. Brown, Jr., both of which are assigned to the present assignee, there are described various forms of cartons particularly adapted to receive eggs. These cartons are integrally formed of a plastic material such as foamed polystyrene and comprise generally a bottom egg-receiving portion and a lid with an integral hinge along one of the pairs of corresponding longitudinal edges. Opposite the hinged edges are formed a plurality of latch means for releasably maintaining the lid and bottom portion in closed relationship.

The latch structure described in the aforementioned copending applications comprise generally a plurality of hooks formed on the ends of protrusions provided along the edge of the bottom portion of the carton which, when the carton is closed, engage correspondingly placed, inwardly extending bulges or detents formed in the wall of the carton lid. Both the hooks and catches are disposed entirely inwardly of the edge of the carton so as to require no additional material for its manufacture, as well as to simplify packing and shipping. In addition, the latch construction shown therein reduces the tendency of the carton to open upon racking or twisting during handling. In the later filed of the above applications, the possibility of accidental opening of the carton is further minimized by the employment of a single crease hinge.

The object of the present invention is to further increase the effectiveness of cartons of the type disclosed and claimed in the foregoing applications by adding substantially to its resistance to accidental opening upon twisting or racking, such as occurs during the packing of filled egg cartons for shipment.

BRIEF SUMMARY OF THE INVENTION

In accordance with this invention, the egg carton is formed with the top and bottom portions preferably hinged along one longitudinal edge and provided with latch means, such as of the type disclosed in the the aforementioned copending applications, along the other pair of longitudinal edges. Along with the latches, the mating carton edges are provided with additional detent means to increase the rigidity of the structure when closed. These detent means comprise one or more cutouts along the edge of one portion of the carton and mating, vertically extending lips along the edge of the other portion, whereby upon closure of the carton, the lips engage the cutouts in the respective halves of the carton. The engagement of the lips in the cutouts prevents appreciable relative longitudinal motion along the latched edges of the carton, thereby substantially reducing the tendency of the latches to disengage upon relative twisting motion between the ends of the carton.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be had to the following detailed description thereof and to the accompanying drawings, in which:

FIG. 1 is a perspective view of the carton according to the invention in a partially open position;

FIG. 2 is an elevation view of the carton in closed position showing the novel structure of the invention; and

FIG. 3 is a cross section through the carton of the invention taken along the lines 3-3 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

An egg carton embodying the invention is illustrated in partially open position in FIG. 1. The carton 11 consists of a top portion or lid 12 and a bottom portion 13, of generally rectangular shape, and preferably integrally formed from a single sheet of material. The latter conveniently may be a plastic substance such as foamed polystyrene, although any suitable moldable material may be used. Foamed polystyrene is particularly convenient since it may be readily thermoformed on machinery of the type commonly used in the industry.

The top and bottom portions of the carton 11 are coupled by a hinge 14 traversing the material integrally joining the portions along the pair of corresponding longitudinal edges 15. The hinge is formed by making one or more creases or crimps in the carton material on either side and may be continuous or interrupted by a series of spaced longitudinal cuts along the crease.

The bottom portion 13 of the carton contains a series of article-receiving cells 19, which, in the embodiment illustrated, are shaped and dimensioned to accommodate eggs of any of the standard sizes. The top portion or lid 12 has a generally flat upper wall 20, sloping sidewalls 21, and sloping endwalls 22. The dimensions of the top portion are such that, when the lid is closed and latched, the eggs are snugly held in the cells.

In the preferred embodiment shown, the individual cells of each cluster are separated by vertical posts 28 and the lid is formed with a downwardly extending, longitudinal rib or ribs 29. When the lid is closed, the ribs 29 bear on the posts 28, adding to the rigidity and strength of the carton.

Latch means indicated generally at 23 are formed in the top and bottom portions of the carton along the pair of common edges opposite the hinge, between pairs of cells 19. Openings 24 along the transverse edges of the cartons may be provided to permit air circulation and to allow limited viewing of the contents.

Each latch means 23 comprises a hook 25 formed by the upper end of the protrusion 27 extending vertically from the bottom portion of the carton, adjacent to but inwardly of the flange 30 which runs along the length of the bottom portion. In the forming process, the protrusion 27 is molded and then cut back to form the hook 25 and the cutout 32 along the carton flange 30. A cutout 32 is thereby provided in the flange 30 of the bottom portion below each of the hooks 25.

The catch portion of the latch means is formed along the longitudinal sidewall 21 of the carton lid by producing an outwardly extending boss 34 in which is pressed an inwardly extending detent or bulge 26. As seen in FIG. 3, the latter is located such that when the carton is in its closed position, the detent 26 engages the hook 25 on the bottom of the carton.

Immediately below the detent 26 along the flange 31 extending along the longitudinal edge of the lid portion, there is provided a lip 36 which is sized to fit snugly within the cutout 32. The lip is formed in the same operation as that required to produce the detent 26, and, since it is actually a depressed portion of the existing flange 31, no additional material is required.

One or more of the catches on the lid 12 is provided with a lip 36 such that when the carton is closed, each of the cutouts 32 on the bottom portion engages a corresponding lip 36 in the lid.

As can be appreciated, with the lips in position in the cutouts 32, the edges of the carton along which the latching means are disposed are substantially incapable of relative longitudinal movement. That is, the upper part of the carton cannot be moved longitudinally with respect to the lower part to any appreciable extent. This extra degree of rigidity, not found in prior cartons, coacts with the latch means shown to provide substantially increased resistance to racking forces generated by relative twisting of the ends of the carton. Such racking forces are often encountered during the packing of filled cartons of eggs prior to shipment and heretofore, have often resulted in opening of the cartons and damage to their contents.

Although the cutouts 32 and lips 36 preferably are formed as part of the respective hook and catch portions of the latching means for ease in manufacture, it is not necessary that they be so located. If desired, the cutouts and lips and may be located at other positions along the flanges in the carton edges; it being necessary only that the engagement be effective to resist longitudinal motion between the carton halves along the latching edge. Moreover, a cutout and lip need not be provided at each latch means, a lesser number being capable of adding the desired longitudinal rigidity. It will also be understood that the invention described herein may be employed in cartons of other shapes and types as well as of other materials, for example, in cartons having no hinge, i.e. where the top is completely removable and reliable latch means are provided along both pairs of longitudinal edges. In such a configuration the cutouts and lips would be formed along both sides of the carton.

Claims

I claim:

1. A carton for containment of eggs comprising a bottom portion formed with a plurality of egg-receiving cells, a top portion having sidewalls and formed to fit over and contain eggs placed in said egg cells, said bottom and top portions meeting when closed in pairs of corresponding edges and having outwardly extending flanges at least along one of said pairs of corresponding edges, said edges and flanges meeting in a common plane and defining the outer dimensions of the carton in said plane, latch means for releasably securing the top and bottom portions together along one pair of corresponding edges, said latch means comprising a hollow, vertical protrusion formed in said bottom portion adjacent an edge thereof, said protrusion being located between a pair of adjacent egg cells and having a hook extending outwardly towards but not beyond the edge of the bottom portion, and a catch for engaging said hook, said catch being formed in said top portion adjacent the corresponding edge thereof, and having an inwardly extending bulge formed in a sidewall of said top portion, a cutout and a lip, said cutout formed in the flange on said bottom portion and being located between a pair of adjacent egg cells, said lip formed in the flange on said top portion and extending downwardly below said flange, said lip engaging said cutout when said top and bottom portions are fitted together, and means for securing said top and bottom portions together along a pair of corresponding edges opposite to said pair of corresponding edges adjacent said latch means.

2. A carton in accordance with claim 1 wherein a latch means, a cutout, and a lip are located between each pair of adjacent egg cells at least along one of said pairs of corresponding edges, said edges having flanges thereon, said cutouts formed in the flange of said bottom portion immediately adjacent the hollow vertical protrusions of said respective latch means, and said lips formed in the flange of said top portion immediately below the catches of said respective latch means.

3. A carton in accordance with claim 1 wherein the carton is integrally formed of foamed polystyrene plastic.

4. A carton in accordance with claim 1 wherein said means for securing the top and bottom portions together comprises hinge means.