Container with integral reinforcing flange

A container for bulk materials, especially fluid materials, has integral reinforcing flanges on at least one of its top and bottom ends to resist bulging of the container side walls due to the pressure of the container contents. The flanges are tubular in transverse cross-section and are formed of a plurality of panels, with at least some of the panels having interfitting projections and recesses on adjacent ends thereof to interlock with one another and hold the flanges in erected condition. Corner posts may be inserted into the corners of the container, extending from the top to the bottom thereof, to reinforce the container for stacking of multiple containers on top of one another. The reinforcing flanges at the bottom end of the container have an upwardly and outwardly sloping support surface, and a tray insert having a marginal edge surface complementary to the support surface is supported on the support surface to form a bottom wall in the container.

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 flanges in their
 interlocked folded relationship.
 A flexible bag can be placed in the container in accordance with known
 technology to hold liquid materials such as, e.g., fruit juices, pastes,
 purees and other liquid food products, adhesives, and other materials. A
 die cut opening can be provided near the bottom of the container for
 accommodating a valve or spout when liquid products are placed in the
 container.
 Although the container shown in the drawings is rectangular in
 cross-section, the principles of the invention could be applied to a
 container having other shapes, e.g., octagonal. Moreover, if the container
 is made of corrugated cardboard, the corrugations could run or extend
 vertically in the side walls, thereby increasing the stacking strength of
 the container.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring more particularly to the drawings, a container in accordance with
 the invention is indicated generally at 10 in the drawings. In the
 embodiment illustrated and described herein, the container has a
 rectangular configuration with first and second pairs of opposed side
 walls 11, 12 and 13, 14, respectively. First and second pairs of rolled
 reinforcing flanges 15, 16 and 17, 18 are integrally formed on the first
 and second pairs of opposed side walls, respectively, at the top end 19 of
 the container (see, e.g., FIGS. 2, 10 and 13), and corresponding pairs of
 rolled reinforcing flanges 15a, 16a and 17a, 18a are preferably formed on
 the bottom end 20 (see, e.g., FIGS. 2, 18 and 19).
 In the particular embodiment of the invention illustrated and described
 herein, the reinforcing flanges are triangularly shaped in transverse
 cross-section. The flanges at the top end of the container respectively
 present surfaces S.sub.1, S.sub.2, S.sub.3 and S.sub.4 that are
 essentially coplanar with one another and with the top end of the
 container, and surfaces S.sub.5, S.sub.6, S.sub.7 and S.sub.8 that extend
 downwardly and outwardly from inner marginal edges of the surfaces
 S.sub.1, S.sub.2, S.sub.3 and S.sub.4 to an adjacent side wall.
 The flanges at the bottom end of the container similarly present
 corresponding outer surfaces S.sub.1 a, S.sub.2 a, S.sub.3 a and S.sub.4 a
 that are essentially coplanar with one another and with the bottom end of
 the container, and surfaces S.sub.5 a, S.sub.6 a, S.sub.7 a and S.sub.8 a
 that extend upwardly and outwardly from inner marginal edges of the
 surfaces S.sub.1 a, S.sub.2 a, S.sub.3 a and S.sub.4 a to an adjacent side
 wall.
 The surfaces S.sub.5 a, S.sub.6 a, S.sub.7 a and S.sub.8 a define an
 upwardly and outwardly angled annular support surface surrounding the open
 bottom end of the container, on which a tray-shaped bottom insert 25 may
 be supported (see FIGS. 20-23).
 Corner posts 26, 27, 28 and 29 are preferably inserted through openings 30,
 31, 32 and 33 (see FIGS. 10, 13, 14 and 20-22) formed through the top
 flanges 15-18 at the top corners of the container to reinforce the
 container for improved vertical stacking of multiple containers, and a
 cover 34 may be provided to close the open top.
 Although not essential to the invention, one or more liner sleeves 35, 36,
 shaped complementally to the shape of the container side walls, may be
 inserted into the container to provide additional strength. See FIGS. 4a,
 4b, 11, 12 and 23.
 Further, a flexible bag or liner (not shown) may be placed in the container
 to hold liquid products such as fruit juices, pastes, purees and other
 liquid food products, adhesives, and the like. A die cut opening 37 (FIG.
 2) may be provided near a bottom end of one of the side walls to
 accommodate a valve or spout (not shown) to remove product.
 Further details of construction and assembly of the flanges 15, 16, 17 and
 18 at the top of the container can be seen best with reference to FIGS. 3
 and 6-14. The first pair of opposed side walls 11 and 12 have identically
 shaped flaps 50 and 51, respectively, on their upper ends, each comprised
 of a first or inner panel 52 having a rounded notch or cutout 53 in each
 of its opposite ends, a second or intermediate panel 54 having an
 irregularly shaped cutout 55 in each of its opposite ends, defining a
 laterally projecting tab 56, and a third or outer panel 57 having a
 generally triangularly shaped flap 58 on each of its opposite ends.
 The second pair of opposed side walls 13 and 14 also have identically
 shaped flaps 60 and 61, respectively, on their upper ends, each comprised
 of a first or intermediate panel 62 having a rounded notch or cutout 63 in
 each of its opposite ends, a second or intermediate panel 64 having a
 slightly rounded rectangular cutout 65 in each of its opposite ends, and a
 third or outer panel 66 having a generally rectangularly shaped flap 67 on
 each of its opposite ends.
 To erect the flanges formed by flaps 50, 51 and 60, 61, and with particular
 reference to FIGS. 6-14, the flaps 60 and 61 are first folded inwardly
 over the open end of the container, as shown in FIG. 7. The intermediate
 panels 64 are then folded inwardly and downwardly about the score lines
 separating them from panels 62, so that the panels 64 extend angularly
 outwardly and downwardly to the respective adjacent side walls, with
 panels 62 lying substantially coplanar with the end of the container, and
 panels 66 extending downwardly from the lower edges of panels 64 and lying
 against the respective side walls, as shown in FIG. 8, to form the tubular
 flanges 17 and 18.
 The outer panels 57 of flaps 50 and 51 are next folded inwardly about the
 score lines separating these panels from intermediate panels 54, so that
 the panels 57 lie against the inside surface of panels 54, as shown in
 FIG. 8. The flaps 50 and 51 are then folded downwardly about the score
 lines joining them to the adjacent side walls, so that the flaps lie
 substantially coplanar with the end of the container, and the opposite
 ends of panels 54 and 57 are bent upwardly about score lines 69 and 70, as
 shown in FIG. 9. Panels 54 and 57 are then pressed downwardly past the
 folded flanges 17 and 18, whereby the flaps 58 on panels 57 slide past
 angled panels 64 and "snap" into the cutouts 65 on panels 64. It will be
 noted that with the panels thus folded, and the flaps 58 engaged in
 cutouts 65, a shoulder 71 is formed on the ends of panels 54, and this
 shoulder engages against the panel 64. The engagement of flap 58 in cutout
 65 and the engagement of shoulder 71 against panel 64 securely interlocks
 the panels in their folded condition, as shown in FIG. 10, to form the
 tubular flanges 15 and 16.
 Additionally, with the flanges folded as described above, the notches 53
 and 63 on adjacent panel ends are in registry with one another to form the
 rounded openings 30-33 in the corners of the container, and the cutouts or
 notches 55 and 65 in panels 54 and 64, respectively, are in registry with
 one another to form openings 75 (see, e.g., FIGS. 14 and 20) between the
 adjacent ends of the flanges and in alignment with the openings 30-33.
 With particular reference to FIGS. 3 and 15-19, where the container is
 shown inverted, with its bottom side uppermost, flaps 50a, 51a and 60a,
 61a substantially identical to those on the top end of the container are
 formed on the bottom ends of the side walls 11, 12 and 13, 14,
 respectively, except that the first or inner panels 52' and 62' do not
 have rounded cutouts or notches in their opposite ends. Instead, the
 opposite ends 80 of the panels 52' extend substantially collinear with the
 opposite edges of the associated side walls, and the opposite ends 81 of
 the panels 62' are slightly inwardly inclined relative to the side edges
 of the associated side panels. The result of this is that when the panels
 52', 54', 57' and 62', 64', 66' are folded as shown in FIGS. 15-19, and
 substantially identically as described in connection with the panels at
 the top end of the container, an inner opening 75' (see FIGS. 19 and 20)
 is formed between adjacent ends of the angled panels 54' and 64', but no
 opening exists through the overlapping adjacent ends of panels 52', 62'.
 Thus, when the container is in an upright position and corner posts 26-29
 are inserted through the openings 30-33, the lower ends of the corner
 posts will rest on the overlapping adjacent ends of panels 52' and 62'.
 In addition to the fact that the openings in the flanges at the top and
 bottom ends of the container serve to hold the corner posts in position,
 it should be noted that the corner posts also function to help retain the
 flanges in their folded positions. That is, when the posts are inserted
 through the respective aligned openings in the flanges, they extend
 inwardly of and against the flaps 58 and the panel ends 67 (see, e.g.,
 FIGS. 13 and 14), holding them in position and preventing unfolding of the
 panels.
 A container constructed in accordance with the invention is very effective
 in containing bulk quantities of liquids, e.g., 250-300 gallons, and may
 be safely stacked as many as six high. The rolled reinforcing flanges at
 the top and bottom ends of the container resist bulging of the side walls
 due to pressure of liquid stored in the container, and also hold corner
 posts in position, when corner posts are used to increase stacking
 strength.
 While particular embodiments of the invention have been illustrated and
 described in detail herein, it should be understood that various changes
 and modifications may be made to the invention without departing from the
 spirit and intent of the invention as defined by the scope of the appended
 claims.