Collapsible container

A collapsible container for use in the shipping of goods is formed from a single sheet (10) of a plastic material to form a box. The container has a bottom panel (12) and first (14) and second (16) pairs of like wall panels integrally hingedly connected to the bottom panels so that the walls can be erected from a collapsed position to an upright position and vice versa. The end panels include hinged locking flaps (f) formed with locking ribs to releasable engage with the adjacent edges of the side panels. The container is adapted to nest in superposed relationship with a like container when the containers are in a collapsed condition so that the height of a stack of collapsed containers is minimized.

This invention relates to a collapsible container and particularly, 
although not exclusively, a container for the shipping of perishable goods 
such as fish. A container according to this invention is formed from a 
single moulding of a plastics material such as polyethylene to form a box 
or transport case which comprises a bottom panel and first and second 
pairs of like wall panels hingedly connected to the bottom panel. A lid or 
cover may be provided preferably as a separate item to close the open top 
of the box. Containers according to the invention may also be stacked one 
upon the other so that it is often unnecessary to provide a lid for each 
container. 
Non-collapsible cases with insulating properties for shipping fish and 
formed from expanded or foamed polystyrene are known but these known cases 
are not returnable and have become regarded by virtue of their 
composition, as being environmentally unacceptable. 
Such containers do have the advantage of low cost. A collapsible, 
returnable and reusable container is desirable for the shipping of fresh 
(chilled) or frozen fish. A unitary knockdown foamed polystyrene shipping 
container is know from U.S. Pat. No. 3,675,808 but is not robust enough 
for repeated return (round-trip) journeys. Moreover, the foamed material, 
at least to some extent, absorbs fluids and would on this count alone be 
unsuitable as a reusable fish box. U.S. Pat. No. 4,235,346 discloses a 
lightweight collapsible shipping container having a unitary moulded 
construction in which a bottom panel is integrally hinged to four 
peripheral side panels and a top panel is hinged to one of the side 
panels. However, this container is also intended to be formed from a 
foamed plastics material and is unsuitable for use as a reusable fish box 
for the reasons given above. 
Collapsible containers having a more robust and acceptable composition are 
known from e.g. U.S. Pat. No. 4,005,795 which discloses a container formed 
from a unitary blank of polypropylene in which side panels are integrally 
hinged to a bottom panel. There are provisions to lock together with side 
and end panels when they are brought into an upright position comprising 
stud and socket connections. However, the particular arrangement disclosed 
is insufficiently secure in view of the anticipated static and impact 
loading imposed upon a container according to the present invention 
utilized as a shipping container for fish. U.S. Pat. No. 3,675,808 
discloses a collapsible box in which the side and end panels are secured 
together by means of a dovetail type tongue and recess. 
The present invention seeks to achieve a robust but relatively low cost 
collapsible, returnable and reusable shipping container which for return 
shipment, can be put into nested superposed relationship with like 
containers, when collapsed so that the height and space occupied by a 
stack of collapsed containers is minimized. 
The present invention provides a collapsible container for use in the 
shipping of goods, including perishable goods, and comprises a single 
moulding of a plastics material to form an open-topped box which comprises 
a bottom panel and first and second pairs of like wall panels hingedly 
connected to said bottom panel and wherein each wall panel and said bottom 
panel are integrally hinged together so that the walls can be erected from 
a collapsed position to an upright position and vice versa, wherein 
complementary locking means are provided at adjacent edges of said first 
and second pairs of wall panels so that said side and end panels are 
mutually lockable, when the corners of the container are formed by putting 
the wall panels into an upright attitude, wherein said container is 
adapted to nest in superposed relationship with respect to another like 
container when said containers are in collapsed condition so that the 
height of a stack of collapsed containers is minimized. 
According to a feature of the invention, said panels may include features 
which protrude beyond the medial planes of said panels, said features 
being formed and positioned so as to permit nesting of superposed 
containers. 
According to another feature of the invention, said locking means may 
comprise a retaining face provided by the panels of one pair of panels 
engagable with a retaining face provided by the panels of the other pair 
of panels to prevent collapse of said wall panels. 
According to yet another feature of the invention, the retaining face of a 
panel of one pair of panels may be mutually engaged with the retaining 
face of a panel of the other pair of panels when the corners of the 
container are formed and locked thereby to prevent collapse of the 
containers. 
According to another feature of the invention the retaining face of said 
one panel may be provided by a rib adjacent an end face of that panel. In 
constructions where a rib is provided, the rib may be received in a 
channel provided by the said other panel, one face of the channel 
providing the retaining face of the other panel to prevent collapse of the 
one panel. Preferably, a releasable locking face is hinged to said other 
panel for engagement with the retaining face of said one panel to prevent 
collapse of the other panel. Preferably, the locking face is carried by a 
locking flap hinged to said other panel which locking flap is integral 
with other panel and forms a part of said retaining channel face when 
locked. 
According to yet another feature of the invention, said locking face may 
comprise a rib extending perpendicularly from said locking flap. 
According to a further feature of the invention, said locking rib and said 
one panel may comprise releasable complementary fastening means. 
Preferably, said complementary fastening means are a push-snap fit. 
Moreover, it is also preferred that said fastening means comprise 
complementary notches and pegs formed along the mating adjacent vertical 
edges of said first and second pairs of wall panels and which are hinged 
into engagement when the locking flap is engaged after said wall panels 
are put into their fully upright positions to form said box. 
According to a still further feature of the invention, a secondary 
retaining face may be provided within the channel of said other panel to 
engage an end edge of said one panel within said channel. 
According to yet another feature of the invention, said wall panels may be 
formed with integral handling recesses adjacent their uppermost ends. 
According to a further feature of the invention the underface of said 
bottom panel of one container may be formed with locating means adapted to 
engage complementary locking means formed upon an uppermost rim of another 
like container, said complementary locating means being engagable to 
enhance secure stacking of those containers. 
According to yet another feature of the invention, the complementary 
locating means formed upon said uppermost rim may be adapted to engage 
locating means provided on the underside of a lid so that the lid can be 
secured to close said container and wherein the upwardly exposed face of 
said lid also includes locating means adapted to be engaged by the said 
locating means provided on the underface of the bottom panel of another 
like container thereby to enhance secure stacking of those containers. 
According to a still further feature of the invention, said integral hinges 
between each wall panel and said bottom panel may be continuous along the 
length of the respective wall panel. 
According to yet another feature of the invention, said container may be 
substantially sized to fit a standard European pallet measuring 
1.2.times.0.8 m for return shipment when said container is in a collapsed 
substantially flat condition. 
According to another aspect of the invention, there is provided a 
collapsible container for use in the shipping of goods which comprises a 
single mounding of a plastics material to form an open-topped box which 
comprises a bottom panel and first and second pairs of like wall panels 
hingedly connected to said bottom panel and wherein each wall panel and 
said bottom panel and first and second pairs of like wall panels hingedly 
connected to said bottom panel and wherein each wall panel and said bottom 
panel are integrally hinged together so that the walls can be erected from 
a collapsed position to an upright position and vice versa, wherein 
complementary locking means are provided at adjacent edges of said first 
and second pairs of wall panels so that said side and end panels are 
mutually lockable, when the corners of the container are formed by putting 
the wall panels into an upright attitude, said locking means comprises a 
retaining face provided by the panels of one pair of panels engagable with 
a retaining face provided by the panels of the other pair of panels to 
prevent collapse of said wall panels, wherein the retaining face of said 
one panel is provided by a rib adjacent an end face of that panel and 
wherein a releasable locking face is hinged to said other panel for 
engagement with the retaining face of said one panel, said locking face 
being carried by a locking flap hinged to said other panel and forming a 
part of the retaining face of said other panel when locked.

Referring first to FIG. 1, there is shown a unitary blank 10 of moulded 
suitable plastic material comprising a rectangular bottom panel 12 to the 
peripheral edges of which are hinged first and second pairs, 14, 14a and 
16, 16a respectively, of like wall panels Side wall panels 14, 14a are 
hinged to the opposed longitudinal peripheral edges of bottom panel 12 
along integral continuous hinges 18, 18a so that the wall panels can be 
erected from the collapsed position, in which they are substantially 
co-planar with the bottom panel, until they are upstanding substantially 
normal to the bottom panel, and vice versa. Likewise, end wall panels 16, 
16a are hinged to the opposed transverse peripheral edges of bottom panel 
12 along integral hinges 20, 20a. 
Hinges 18, 18a and 20, 20a, sometimes referred to as "living hinges," 
comprise integrally moulded continuous strips of plastics material which 
are moulded together with the panels of the blank and are significantly 
thinner and hence more flexible than the wall thickness elsewhere in the 
blank. Although such continuous hinge strips will usually be formed from 
the material injected during the moulding process to form the panels of 
the blank, other hinge constructions are envisaged. 
Reference is now made to FIGS. 2 to 5. In order to maintain the wall panels 
upright to form the open topped container the side wall panels are locked 
to the end wall panels. To this end, the opposed vertical edges of the end 
wall panels are each provided with a locking flap "f" which engages the 
external face of a side wall and is locked to it in a snap-fit. Further, 
the vertical internal face of the end wall adjacent each end edge is 
formed with a channel "C," the outermost wall 22 of which provides a 
retaining face to prevent collapsing movement of the side walls, e.g. side 
wall 14 is furnished, adjacent its end edge, with an integral 
perpendicular flange or rib 24. When the end edge of side wall 14 is 
received in the channel "C", which occurs only when the corner of the 
container is properly formed by erecting the wall panels, rib 24 abuts the 
internal face 25 of channel wall 22 (FIG. 5). This abutment retains the 
side wall panel in its upright attitude and prevents it from collapse. 
Likewise rib 24 provides a retaining face to prevent collapse of end wall 
16. However, in order to effectively engage rib 24 the locking flap "f" 
must be engaged. The arrangement at each end of the box is similar and 
therefore only one corner construction is described, it being understood 
that the descriptions of the other corner constructions follow. Locking 
flap "f" is integrally hinged to the end edge of the end wall and includes 
a perpendicular locking rib 26. When the locking flap "f" is engaged it is 
folded into face contacting relationship with the external face of side 
wall panel 14. In so doing, the portion "f1" of the flap between channel 
wall 22 and locking rib 26 forms a part of the channel wall 22 and the 
locking rib 26 engages behind the rib 24. Thus, the mutual engagement 
between the ribs 24 and flap "f" prevent collapse of the end wall panel 
16. 
In order to achieve a positive fastening between the locking flap "f" and 
the side wall panel 14, the side wall is formed with a pair of spaced pegs 
28 located behind rib 24. Pegs 28 locate as a "snap-fit" into spaced 
notches 30 formed in the locking rib 26. 
A secondary locking rib 32 is formed within channel "C" against which the 
extreme end face 33 of the side wall panel engages and thereby gives 
better locking security and a more positive engagement of the wall panel 
edges when the corner of the container is being formed. 
In order to facilitate handling of the box, the end walls are formed, 
adjacent their top ends with an inwardly projecting recess 34 which not 
only increases the vertical compression strength and the rigidity of the 
end wall but provides a handle feature for the end walls of the box. 
Similar handle recesses 36, 38 respectively, are formed in each of the 
side walls of the container, each recess 36 and 38 being separated by 
horizontal 40 and vertical 42 ribbing of the external face of the wall 
which improves the stiffness and stacking strength of the longer side wall 
panels. 
Each of the wall panels includes an inwardly directed top flange 44, 44a 
and 46, 46a, respectively, which together form a raised upper rim R of the 
container when the wall panels are in their erected positions. 
Top lid "L" (FIG. 3) has a peripheral complementary channel (not shown) 
which can be snap-fitted onto the raised rim R of the container. Around 
the edges on the top face of the lid "L" is formed a series of upstanding 
lips 48 and 48a and the underside of bottom panel 12 is formed, adjacent 
its periphery, with a peripheral channel 50 (FIG. 4) so that the lip of 
the lid "L" of an upper container can be located in the channel 50 of a 
lower container to facilitate locking and enhance stacking stability. 
Moreover, since the raised rim R around the top panel walls is vertically 
aligned with the channel 50 of a base, boxes can be stacked by engagement 
of the rim and channel one upon the next in the absence of lids so that 
only the top box of a stack need be lidded. The lid "L" also includes two 
pairs of transverse lips 52, 52a which are received in a relieved section 
54 of the bottom panel of another like container. Lips 48, 52 and 48a, 52a 
so that each of those above groups engages and half of the bottom panel of 
a container stacked transversely thereon. 
Referring now to FIG. 6, the alignment of some of the interlockable 
elements of the container shown in FIG. 6 and previous illustrations, is 
further illustrated in this end view of a partially-erected container. In 
FIG. 6, one end wall 16a and the two side walls have been erected. The 
container is viewed from an open end wherein the end wall 16 is pivoted 
downward. The manner in which the channel "C" formed at each end of the 
end wall 16 is aligned to receive the elements formed at the ends of the 
side walls 14, 14a is illustrated. When the end wall 16 is pivoted upward 
into adjoining relationship with the ends of the side walls 14, 14a, the 
innermost wall of each channel "C" receives the extreme face 33 of a 
respective side wall 14, 14a. At the same time, the internal face 25 of 
the outermost wall 22 of each channel "C" receives and abuts the edge of 
the perpendicular flange or rib 24 of each respective side wall 14, 14a. 
Also upon joining of the end 16 and side walls 14, 14a, the secondary rib 
32 within each channel "C" is brought into abutting relationship with the 
outer surface of the perpendicular flange or rib 24 of each respective 
side wall 14, 14a. 
Referring now to FIG. 7, which is the same end elevational view of a 
partially-erected container as is illustrated in FIG. 6, and, 
simultaneously, also referring to FIG. 8, additional elements of the 
container are illustrated. Proper alignment of the joining elements of the 
end wall 16 and side walls 14, 14a is promoted by means of a tab-like 
member 56 protruding from each channel "C" and a corresponding 
complementary notch 58, formed in each respective perpendicular flange or 
rib 24, for receiving the tab member 56. A tab member 56 and corresponding 
complementary notch 58 are formed and aligned to engage one another when 
the ends of end walls 14, 14a and side walls 16, 16a are brought into 
contact with one another. The tab member 56 is tapered, or bevelled, so 
that its narrowed leading end can easily engage the corresponding 
complementary notch 58. As the end wall 16, 16a is pressed against the 
side walls 14, 14a, each tab 56 is forced through a corresponding 
complementary notch 58 until the flared, or wider, portion of the tab 
member 56 extends into the complementary notch 58. It is the forcing of 
the flared tab member 56 through the complementary notch 58 which brings 
the edge of an end wall 14, 14a into desired alignment with the edge of a 
side wall 16, 16a. 
An additional feature which is illustrated in FIGS. 7 and 8 is a 
modification of the perpendicular locking rib 26 of each flap "f." Each 
perpendicular locking rib 26 may be modified to facilitate engagement of 
each notch 30 in a locking rib 26 with a corresponding peg 28 (not visible 
in FIGS. 7 and 8 but previously discussed above). To alleviate any 
difficulty that might occur in engaging a notch 30 and corresponding peg 
28 due to alignment variances caused during manufacture or continued use 
of the container, a secondary notch 60 is placed in the locking rib 26 
near each notch 30 to form a secondary peg 62. The secondary peg 62 that 
is formed is flexible due to the notches 30, 60 on either side. The 
flexibility of the secondary peg 62 helps alleviate possible difficulty in 
Snapping the pegs 28 into the notches 30 which may be caused by slight 
misalignment of the pegs 28 and respective notches 30. The use of the 
secondary peg 62 in the locking rib 26 greatly reduces or eliminates the 
rigidity and inflexibility of the locking rib 26 when optimum alignment 
between the pegs 28 and respective notches 30 does not occur. 
The panels of the blank are configured so that a stack of blanks can be 
formed with the blanks disposed in superposed nested relationship. For 
instance, moulded features of each panel are all contained with a common 
plane on either side of a medial plane of that panel. Also certain 
features are adapted to nest in other like features such as the handle 
recesses of the wall panels. When the box is collapsed, it is sized to be 
received upon a standard European sized pallet measuring 1.2.times.0.8 m 
for return shipment and refilling. For an outward journey, a pallet will 
receive three containers in each stacked tier of containers.