Envelopes – wrappers – and paperboard boxes – Paperboard box – Rectangular box having a bottom wall initially separate from...
Reexamination Certificate
2000-03-06
2001-05-08
Elkins, Gary E. (Department: 3727)
Envelopes, wrappers, and paperboard boxes
Paperboard box
Rectangular box having a bottom wall initially separate from...
C229S005500, C229S122270, C229S160000, C229S168000, C229S199000
Reexamination Certificate
active
06227442
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to containers, and more particularly, to reinforced bulk material containers for storing and shipping fluid materials.
2. Prior Art
Containers for storing and shipping bulk quantities of materials are known in the prior art. These prior art containers include metal drums, plywood bins, metal frame constructions and fiberboard or cardboard boxes and drums. Containers for the bulk storage and shipment of fluid materials, in particular, commonly consist of metal drums because of their strength and durability. However, since these types of containers are relatively costly to produce, they are typically saved and reused, which is also at a relatively high cost, particularly in relation to the storage and shipment of the empty containers.
Although fiberboard and cardboard boxes and drums are generally less expensive to make, and some of them therefore may be economically disposed of after a single use, they may have less strength and durability than metal or plastic drums and similar “hard” containers. For instance, cardboard containers may not have sufficient “stacking” strength, and when the container is used for holding fluid material, there is a tendency for the container walls to bulge outwardly under the pressure of the contents. Accordingly, they are not used as often as otherwise may be desired in the storage and shipment of bulk materials, and especially fluid materials.
Efforts have been made in the prior art to develop stronger and more durable fiberboard and cardboard containers for the bulk storage and shipment of materials, including fluid materials. Examples of some prior art constructions are shown in U.S. Pat. Nos. 2,603,402, 3,294,306, 4,105,153, 4,341,338 and 4,623,075. U.S. Pat. Nos. 2,603,402 and 3,294,306, in particular, disclose cardboard containers having structure to improve stacking strength and/or bulge resistance. Note the rolled flanges at the top and bottom of the container in U.S. Pat. No. 2,603,402, and the interengaged flanges and corner posts in U.S. Pat. No. 3,294,306. The rolled flanges in the '402 patent have cuts that define mitered corners which frictionally interengage when the flanges are in their erected condition, and the flanges in the '306 patent have cuts which define openings that receive the corner posts when the container is in its erected condition. The mitered corners in the '402 patent do not interlock, but merely frictionally engage one another to retain them in their rolled condition, and there is no provision for receiving corner posts to improve stackability. The flat flanges in the '306 patent do appear to interlock with the corner posts inserted in the openings at the corners of the box, to retain the flanges and corner posts in position, but there does not appear to be any interlocking of the flanges in the absence of the corner posts, and the flat flanges would appear to provide only limited bulge resistance.
Accordingly, there exists a need for an economical bulk material container of cardboard or fiberboard construction having rolled flanges at least at one end of the container to resist bulging of the sidewalls, and corner posts to improve stackability, wherein the bulge resisting flanges have interlocking portions to retain them in position in either the presence or the absence of the corner posts.
SUMMARY OF THE INVENTION
In accordance with the present invention, an economical bulk material container of cardboard or fiberboard construction is provided, having integral, rolled reinforcing flanges at least at one end of the container to resist bulging of the sidewalls. Mutually interlocking portions are on adjacent flanges to retain them in their rolled, operative position, and corner posts may be provided to improve stackability. The flanges have openings to receive the corner posts and support them in their operative position, and the corner posts cooperate with the interlocking means to assist in retaining the flanges in their operative position.
More particularly, the container of the invention comprises a corrugated cardboard blank folded to define an enclosure having side walls and open ends, with integral flaps on the side walls at least at one of the ends folded to define rolled reinforcing flanges to resist bulging of the sidewalls under the pressure of the contents of the container. The flaps are divided by spaced parallel fold lines into a plurality of adjacent, side-by-side panels, with notches and tabs on the ends of adjacent flaps constructed to interlock with one another when the panels are folded about the fold lines into their erected configuration.
In that form of the invention disclosed herein, the flaps comprise a first or inner panel foldably joined to an adjacent side wall, a second or intermediate panel foldably joined to the inner panel, and a third or outer panel foldably joined to the intermediate panel.
The notches and tabs on the ends of the flaps are formed by a suitable method, e.g., by die-cutting, and are shaped so that when the panels are correctly folded about the fold lines, tabs project outwardly from the ends of one of the panels on one flange and extend into interlocking relationship in notches in an end of a panel of an adjacent flange. Portions of other panels on adjacent flanges abut one another to assist in retaining the panels in their interlocked relationship.
When erected, the panels form a rolled tubular flange having a triangular transverse cross-sectional shape, with the first or inner panel defining a flat surface substantially coplanar with the end of the container and facing outwardly thereof, and the second or intermediate panel defining an inclined surface extending inwardly of the container and toward the adjacent side wall from an inner marginal edge of the flat surface. The third or outer panels in the flanges on a first pair of opposed side walls of the container are folded toward the opposite end of the container to lie flat against the adjacent side wall when the flange is erected, and the outer panels in the flanges on a second pair of opposed side walls are folded inwardly behind the inclined intermediate panel to lie behind the flange flat against the adjacent side wall of the container.
While this triangular configuration provides bulge resistance with minimal encroachment into the interior space of the container, it is to be understood that a different number of panels could be provided to form flanges with other cross-sectional configurations, e.g., square or rectangular, without departing from the spirit and scope of the invention.
One or more tubular liner sleeves may be placed in the container to reinforce the side walls, if desired. These sleeves can be laminated together and to the side walls, or may be simply formed into a tube and inserted into the container.
In a preferred construction, rolled reinforcing flanges are formed on both ends of the container, with the flanges on the bottom end of the container defining a peripheral, interior, downwardly and inwardly inclined surface.
A shallow tray insert with an upwardly and outwardly inclined peripheral wall is inserted into the container to rest at its periphery on the inclined surface of the flange at the bottom of the container. This tray insert provides a bottom in the container, and performs the function that would otherwise have been provided by the flanges on the bottom of the container if they had not been folded to create the reinforcing flange.
In a further preferred construction, cut-outs are provided in the ends of the panels to form generally circular openings at the corners of the container when the flanges are erected, extending completely through the top flanges but only partially through the bottom flanges. Corner posts can then be inserted through the openings in the top flanges and into the openings in the bottom flanges to provide improved stacking strength. Engagement of the corner posts in the openings serves to hold the corner posts in position, and also serves to help hold the flang
Elkins Gary E.
International Paper Company
Lambert Dennis H.
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