Collapsible container

Abstract: Containers 10 have a base 12 and four side walls 14 which may fold to a stowed or collapsed position. Hinges connect each wall 14 to an intermediate member 16 which is clipped (preferably removably) to the base 12. Various interlocking formations 34, 36, 38, 40 allow containers to stack securely whether collapsed or erect.

Description: The present invention relates to collapsible containers. Containers which can collapse to a more compact form when not in use are desirable for a number of situations, such as delivery of retail goods. Containers loaded with retail goods can be transported to the retailer, emptied, collapsed and then returned in their collapsed condition. This makes return transport easier by minimising the volume to be transported. U.S. Patent No. 5070577 describes a collapsible container in accordance with the preamble of claim 1, each wall of the container having a seperable hinge formed in the wall. U.S. Patent No. 5070577 refers to earlier U.S. Patent No. 4809851 which describes a collapsible container. The invention provides a collapsible container comprising a base, at least one side wall which may fold over the base to a stowed position when the container is not in use, an intermediate member, hinge means connecting the intermediate member with a first one of the side wall and the base, and attachment means operable to releasably attach the intermediate member to a second one of the side wall and the base, the intermediate member and the said second one of the side wall and the base being manufactured separately, and subsequently assembled by means of the attachment means; characterised in that the attachment means comprise cooperating formations, which provide a first phase of assembly which serves to bring a first formation provided on a first one of the intermediate member and the side wall, or the base, to mate with a second formation provided on the second one of the intermediate member and the side wall, or the base, and which further provide a second, subsequent, phase of assembly in which locking is performed by movement of one of the intermediate member and the side wall, or the base, in relation to the second of the intermediate member and the side wall, or the base, the locking serving to prevent the first phase being reversed, the locking remaining effective while the side wall is folded as aforesaid. Preferably the intermediate member extends along substantially the whole length of the side wall. The intermediate member may be located below the lower edge of the side wall, in use. The attachment means may comprise cooperating projections and recesses. There may be detent means, preferably snap-together detent means, operable to retain the cooperating formations together. The cooperating projections and recesses may comprise a hook formation for introduction into a recess in a first direction, movement in a second direction serving to engage the hook with the walls of the recess, thereby locking the projection and recess together. The attachment means may incorporate resilience for retaining the attachment means in the attached condition. The hinge means may comprise a live hinge. Preferably the hinge means connects the intermediate member with the side wall, and the attachment means attaches the intermediate member to the base. The base may have rectilinear shape and the container may comprise four side walls as aforesaid, and corresponding intermediate members connected and attached as aforesaid. Preferably the container comprises stacking formations able to interlock with corresponding formations on a like container when the containers are in the erect or collapsed condition, and are stacked one on the other, the stacked containers being substantially prevented from relative movement by the interlocking of the stacking formations. Embodiments of the present invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which: Fig. 1 is a schematic perspective view of two containers according to the invention, being stacked in their erect condition; Fig. 2 is a more schematic exploded view of one of the containers of Fig. 1: Fig. 3 is a highly schematic perspective view of the container of Fig. 2 in the partially collapsed condition; Fig. 4 is an exploded section along the line IV-IV in Fig. 2; Fig. 5 shows the containers of Fig. 1 being stacked in the collapsed condition; and Fig. 6 is a schematic plan view of the stacking pattern of the containers of Fig. 5. Referring to the figures, there is shown in Fig. 1 two collapsible containers 10 each comprising a base 12, four side walls 14 which may fold to a stowed or collapsed position (shown in Fig. 5) when the container is not in use. Each side wall 14 is associated with an intermediate member 16. Hinge means connect (in this example) each intermediate member 16 with the corresponding side wall 14. Attachment means (to be described in relation to Fig. 2) attach the intermediate members 16 to the base 12. The intermediate members 16 and the base are manufactured separately and subsequently assembled by means of the attachment means to be described. In more detail, each container 10 has a generally rectangular base 12 from which the four side walls 14 extend upwardly when the container is in the erect condition, to form a generally parallelepipedal container with an open top. In the example shown, which has a base of approximately 600mm x 400mm, one pair of opposed side walls is shorter than the other pair of opposed side walls. Each side wall is connected along its lower edge 18 to the corresponding intermediate member 16 which runs along the whole length of the wall 14. The connection is by means of a "live" hinge, that is, a thin web 19 (Fig. 4) of material connecting the wall 14 and member 16 and sufficiently thin to flex, allowing the wall 14 to hinge relative to the member 16. Preferably, the various components of the container are manufactured in a plastics material, preferably by injection moulding. The side wall and intermediate member can therefore be manufactured as a single element having much reduced thickness at the hinge 19. When the container is in the erect condition, the side walls 14 stand on the intermediate members 16. However, the container 10 can be collapsed in the manner indicated in Fig. 3. The two shorter walls 14 are first folded toward each other to lie across the base 12. Fig. 3 shows the shorter walls fully folded to this stowed position. It is to be noted that the height of the intermediate members under the shorter walls is less than the height of the intermediate members under the longer walls so that in the position shown in Fig. 3, the upper face of the shorter walls is at or below the line of the hinges connecting the longer walls to their corresponding intermediate members. This allows the longer walls to be folded toward each other, down across the base and over the shorter walls. The container is then in the collapsed position shown in Fig. 5, which also shows additional features to be described below. The intermediate members 16 are attached to the base 12 by a series of recesses 20 and projections 22 shown in Figs. 2 and 4. Each projection 22 is generally L-shaped to form a hook having a short downwardly extending limb 24 finishing at an elbow 26, from which a generally horizontal and relatively long limb 28 extends away parallel to the length of the member 16. The recesses 20 are generally rectangular and aligned parallel with the intermediate members 16. Their length corresponds with the length of the limb 28. This allows the members 16 to be lowered to introduce the limbs 28 into the recesses 20, whereupon the members 16 can be slid sideways parallel to the length of the members 16, to hook the long limbs 28 under corresponding surfaces 30 (Fig. 4) within the recesses 20. Alternatively, the second movement could be in a different direction, such as twisting. There are preferably detent means associated with the recesses and projections to hold them together once connected. These may be permanent, but are preferably releasable to allow an intermediate member 16 to be removed by reversing the sequence of operations described above. This allows an intermediate member 16 and the corresponding side wall 14 to be removed and replaced, for instance to repair damage. Arrangements for holding the intermediate member 16 and base 12 together may be resilient as indicated in Fig. 2, in which a small resilient upstand 32 projects above the surface of the base 12, to be pushed down when the intermediate member 16 is lowered into position. The resilience of the upstand 32 causes it to push the intermediate members 16 upwardly after connection to the base, thereby increasing friction between the limbs 28 and surfaces 30, to hold the intermediate member 16 in position on the base 12. Many other types of connection arrangement could be used to securely connect the intermediate members 16 to the base 12. Other types of hinge could also be used. In the example described above, it is preferred to provide the hinge between the intermediate member 16 and the side wall 14, with the attachments between the members 16 and the base 12 being detachable. However, it may in some circumstances be advantageous to provide the hinge between the member 16 and the base 12, with the members 16 and the corresponding walls 14 being attached by an arrangement similar to that shown, or any of the alternatives. The containers shown in the drawings also incorporate a number of features which assist stacking. As has been described, the containers have a base 12 and side walls 14 with an erect condition and a collapsed condition. The container 10 further comprises stacking formations 34,36,38 and 40. Firstly, the side walls 14 have top edges (when erect) which are castellated to form notches 34. These overlie downward projections 36 from the base 12 so that a container base can be stacked on a container below when the lower container is in the erect condition, by lowering the base of the upper container until the base projections 36 on the upper container sit in the notches 34 in the lower container. The notches 34 and projections 36 then engage to stop the upper container sliding relative to the lower container. This assists secure stacking. One arrangement uses projections 36 which fit closely in corresponding notches 34. Alternatively, projections 36 could be shorter than the notches 34, so that one notch 34 prevents sliding in one direction, with another notch preventing sliding in the opposite direction. In the arrangements shown, the locations of the notches 34 and projections 36 also allows containers to be stacked when rotated through 90°, there being three notches 34 and projections 36 along each longer side of the rectangular container, and two notches 34 and two projections 36 along each shorter side. When stacked in this way, the upper container will overhang the lower container by approximately one third of its length. Secure stacking in which relative sliding is prevented can also be achieved when the lower container is in the collapsed condition. This is illustrated in Fig. 5. Two containers are shown there, both collapsed. Depressions 38 formed in the face of the side walls 14 now face upwardly by virtue of the collapsed condition of the containers. In addition, notches 40 around the edges of the walls 14, including notches along the edge 18, become exposed when the container is collapsed. The arrangement and form of these depressions and notches allows them to receive the projections 36 from a like container stacked from above. The arrangement allows stacking two containers in alignment, or at right angles to one another (as shown). When stacked at right angles, two projections 36 at the short side of the base 12 sit in two notches 40 at the lower edge of a longer wall 14 of the lower container, leaving a third notch 40 unoccupied. Two projections 36 on the base of the upper container sit in depressions 38, one in each of the longer walls 14 of the lower container. Another two projections 36 (obscured in Fig. 5) sit in notches at the obscured end of the walls 14. A corresponding two notches 40 at the visible end are unoccupied. The spacing and sizes of the notches 34, projections 36, depressions 38, and notches 40 locate the upper container on the lower container to stop the stacked containers sliding relative to each other. The ability to stack collapsed containers at right angles to one another facilitates the creation of a stable stack as will now be described with reference to Fig. 6. First, it should be noted that the depressions 38 are relatively wide, and allow two projections 36 to be located in them, side-by-side, one from each of two containers being stacked side-by-side on the same lower container. Turning to Fig. 6, a layer in a stack of collapsed containers is formed by five containers arranged as indicated by the solid lines. Three containers 50 have their long sides adjacent and their short sides aligned. Two more containers 52 are at right angles to the containers 50 with shorter sides abutting and longer sides adjacent the shorter sides of the containers 50. Fig. 6 also indicates the arrangement on the layer beneath, using broken lines. It can be seen that the arrangement is the same except that the whole layer has been rotated through a half turn. This results in every container overlying at least two containers on the layer below which, by virtue of the interconnecting notches, projections and depressions, yields a secure stack akin to the building of brickwork. Containers of 600mm x 400mm base can be stacked in the manner shown on a standard size pallet. Similar overlapping stacking arrangements can be devised for other container sizes, such as 400mm x 300mm, again with similar advantages. The layout of the interlocking formations for the erect and collapsed containers would vary according to the size of container. It will be apparent from the above description that many variations and modifications can be made without departing from the scope of the present invention. In particular, many different sizes of container could be designed, with corresponding arrangements of interlocking formations. Other hinge techniques could be used, as could alternative arrangements for attaching the intermediate members to the base. Alternatively, the intermediate member and the base could be hinged, with the wall being made separately. The containers have been described as being of plastics material, but other materials could be used. Lock arrangements could be incorporated to hold the container walls in the erect position.

Claims: A collapsible container (10) comprising a base (12), at least one side wall (14) which may fold over the base (12) to a stowed position when the container (10) is not in use, an intermediate member (16), hinge means (19) connecting the intermediate member (16) with a first one of the side wall (14) and the base (12), and attachment means (20,22) operable to releasably attach the intermediate member (16) to a second one of the side wall (14) and the base (12), the intermediate member (16) and the said second one of the side wall (14) and the base (12) being manufactured separately, and subsequently assembled by means of the attachment means (20,22); characterised in that the attachment means (20,22) comprise cooperating formations (20,22) which provide a first phase of assembly which serves to bring a first formation (20, 22) provided on a first one of the intermediate member (16) and the side wall (14), or the base (12), to mate with a second formation (20, 22) provided on the second one of the intermediate member (16) and the side wall (14), or the base (12), and which further provide a second, subsequent, phase of assembly in which locking is performed by movement of one of the intermediate member (16) and the side wall (14), or the base (12), in relation to the second of the intermediate member (16) and the side wall (14), or the base (12), the locking serving to prevent the first phase being reversed, the locking remaining effective while the side wall (14) is folded as aforesaid. A container according to claim 1, wherein the intermediate member (16) extends along substantially the whole length of the side wall (14). A container according to claim 1 or 2, wherein the intermediate member (16) is located below the lower edge of the side wall (14), in use. A container according to claim 1, 2 or 3, wherein the attachment means (20,22) comprise cooperating projections (22) and recesses (20). A container according to claim 4, further comprising detent means (32) operable to retain the cooperating projections (22) and recesses (20) together. A container according to claim 5, wherein the detent means (32) snap together. A container according to any of claims 4 to 6, wherein the cooperating projections (22) and recesses (20) comprise a hook formation (22) for introduction into a recess (20) in a first direction, movement in a second direction serving to engage the hook (22) with the walls of the recess (20), thereby locking the projection (22) and recess (20) together. A container according to any preceding claim, wherein the attachment means (20,22) incorporate resilience for retaining the attachment means (20,22) in the attached condition. A container according to any preceding claim, wherein the hinge means (19) comprise a live hinge. A container according to any preceding claim, wherein the hinge means (19) connects the intermediate member (16) with the side wall (14), and the attachment means (20,22) attaches the intermediate member (16) to the base (12). A container according to any preceding claim, wherein the base (12) has rectilinear shape and the container (10) comprises four side walls (14) as aforesaid, and corresponding intermediate members (16) connected and attached as aforesaid. A container according to any preceding claim, wherein the container (10) comprises stacking formations (34,36,38,40) able to interlock with corresponding formations on a like container (10) when the containers (10) are in the erect or collapsed condition and are stacked one on the other, the stacked containers (10) being substantially prevented from relative movement by the interlocking of the stacking formations (34,36,38,40).

Inventors: HOGGARTH MARCUS, LOFTUS STEPHEN CLIVE, HOGGARTH, MARCUS, LOFTUS, STEPHEN CLIVE, Hoggarth, Marcus, c/o McKechnie UK, Ltd., Loftus, Stephen Clive, McKechnie UK, Ltd.
Applicants: MCKECHNIE UK LTD, MCKECHNIE UK LIMITED
Application year: 1996
Main classification: B65D6
IPC codes: B65D21, B65D6