Background of the Invention It is known from the prior art several box constructions, which are formed in a single piece molded in plastic material and which are used for storing and transporting a large number of products in different situations.

These known usually parallelepipedic plastic boxes, although being largely used, have a common constructive characteristic which turns out to be an inconvenience, whose relevance will depend on the utilization of the box.

This inconvenience is due to the fact that these boxes cannot be disassembled, therefore unnecessarily occupying space when not used.

With the aim to eliminate the above cited inconvenience, many different boxes have been developed, which are capable of being easily disassembled when out of use.

Though these known collapsible box constructions have resulted in products which can easily pass from the operative assembled condition to the inoperative disassembled condition and vice-versa, they have a relatively high cost, due to their complex construction which includes a certain number of components which, besides requiring specific molds, need assembly operations during the production of the box.

One of these known prior art collapsible boxes has a bottom wall which hinges, through multiple pins, the lower edge of two opposite lateral walls, each of said lateral walls being medianly and longitudinally divided in a lower half and an upper half, which are hinged to each other by multiple pins, these two opposite lateral walls and the two opposite end walls being hinged, at their upper portions, through multiple pins, to a structural frame which defines the upper edge of the box.

In this construction, which uses six or more distinct pieces, the disassembly of the box is achieved by angularly displacing the end walls both inwardly and upwardly, towards the plane of the structural frame, while both lateral walls are medianly inwardly bent, thus allowing the structural frame together with the two angularly displaced end walls to be lowered, until the lower halves of the lateral walls are seated on the bottom wall and the structural frame is seated on the edge of said bottom wall. As already mentioned, though this type of box is easily handled and operates safely in the assembled condition, it is of considerable higher cost than the conventional rigid plastic boxes. Moreover, such type of construction usually jeopardizes the structural strength of the box.

Disclosure of the Invention It is an objective of the present invention to provide a collapsible plastic box, which is of simple construction, structuraly resistant and of relatively low cost, and which can be obtained in a single molded piece.

These and other objectives and advantages of the present invention are attained by a collapsible plastic box, which is formed in a single molded piece

and which comprises a bottom wall, with its lateral edges hinging, through respective flexible membranes, the lower edges of two pairs of opposite lateral walls, a first pair being angularly displaceable between a box assembled condition, in which said first pair is orthogonal and superior in relation to the bottom wall, and a box disassembled condition, in which said first pair is seated on the bottom wall, the second pair of opposite lateral walls being angularly displaceable between a box assembled condition, in which said second pair is orthogonal and superior in relation to the bottom wall, and a box disassembled condition, in which said second pair is seated under said bottom wall, each of the lateral edges of the walls of one of said pairs of opposite lateral walls incorporating at least one locking means, which is fitted in a lock receiving means provided at the adjacent marginal portion of a lateral wall of the other pair, in order to retain said walls interconnected to each other against an angular displacement outwardly from the contour of the bottom wall, when in the box assembled condition.

Brief Description of the Drawinqs For a better understanding of the invention claimed herein, it will be described below with reference to the attached drawings, in which: Fig. 1 is an upper plan view, in a reduced scale, of the collapsible plastic box of the present invention, with its lateral walls occupying a position coplanar with the bottom wall; Fig. 2 is a lateral view of the plastic box, taken in the direction of arrow II of figure 1, said view illustrating: in full lines, the box in the disassembled condition ; in dotted and dashed lines, one of the lateral walls thereof being angularly

displaced to the box assembled condition and, in dashed lines, to the condition illustrated in figure 1; Fig. 3 is a lateral view of the plastic box, taken according to arrow III of figure 1, said view illustrating: in full lines, the box in the disassembled condition; in dashed lines, one of its lateral walls being angularly displaced to the condition shown in figure 1 and, in dotted and dashed lines, to the box assembled condition; Figures 4,5 and 6 are sectional views of the plastic box of figures 1-3, taken according to line A-A of figure 1 and illustrating, respectively, the box in the disassembled condition, in the assembled condition and in the condition shown in figure 1; Figures 7,8 and 9 are sectional views of the plastic box of figures 1-6, taken according to line B-B of figure 1 and illustrating, respectively, the box in the disassembled condition, in the condition shown in figure 1 and in the assembled condition; and Fig. 10 is a similar view to that of figure 9, but illustrating the box in an intermediate assembly condition.

Best Mode of Carrying Out the Invention According to the figures mentioned above, the collapsible plastic box object of the present invention is formed in a single piece molded in plastic material, comprising a bottom wall 10, the lateral walls thereof being hingedly joined by means of respective flexible membranes 20 to the lower edges of a first pair 30 and a second pair 40 of opposite lateral walls, respectively.

According to the present invention and to a preferred illustrated construction, the bottom wall 10 has a rectangular contour with its opposite larger lateral

edges being chamfered, in order to define a lateral ramp 11 turned to the upper face of the bottom wall 10, said lateral ramp 11 incorporating along the extension thereof a groove 12, the opposite smaller lateral edges of said bottom wall 10 being also chamfered, so that each defines an end ramp 13 turned to the lower face of the bottom wall 10.

The hinged joint between each larger lateral edge of the bottom wall 10 and the respective lower edge of the respective larger lateral wall 30 is obtained through a flexible membrane 20, which interconnects the lower end of the respective lateral ramp 11 with the lower end of a chamfer 31, which is defined at the respective lower edge of the larger lateral wall 30, each chamfer 31 being turned to the inner face of the respective larger lateral wall 30 and being provided, along the extension thereof, with a rib 32, which has a similar section to that of the groove 12 of the lateral ramps 11 of the bottom wall 10.

The hinged joint between each smaller lateral edge of the bottom wall 10 and the lower edge 43 of the respective smaller lateral wall 40 is obtained through a flexible membrane 20, which interconnects the upper end of the respective end ramp 13 with the inner end of the respective lower edge 43 of the respective smaller lateral wall 40.

With the construction described above, the opposite larger lateral walls 30 are hinged to the bottom wall 10, so as to be angularly displaceable between a box assembled condition, in which said larger lateral walls are orthogonal and superior in relation to the bottom wall 10, and a box disassembled condition, in which they are seated under the bottom wall 10, as illustrated in figure 3, while the opposite smaller lateral walls 40 are hinged to said bottom wall 10, so

as to be angularly displaced between the box assembled condition, in which said smaller lateral walls are orthogonal and superior in relation to the bottom wall, and a box disassembled condition, in which they are seated onto said bottom wall 10, as illustrated in figure 2.

Locking of the four lateral walls 30,40 in the box assembled condition is achieved by locking means which, in the illustrated embodiment, take the form of a pair of pins 35 projecting outwardly from each of the lateral edges of each larger lateral wall 30, in a coplanar manner relative to the latter, each pin incorporating an enlarged head 36 which maintains, in relation to the adjacent lateral edge of the respective larger lateral wall 30, a spacing which is slightly larger than the thickness of the lateral marginal portions of the pair of smaller lateral walls 40. In each of said marginal portions is provided a pair of lock receiving means, each being defined by a window 45, which has an enlarged portion 46 in order to allow the passage of the enlarged head 36 of a respective pin 35 in an assembly condition, in which the smaller lateral wall 40 is in the box assembled condition and the larger lateral wall 30 is in an inwardly angularly retracted position in relation to the box assembled condition, and in which the rib 32 of the lower chamfer of the larger lateral wall 30 is seated in the groove 12 of the lateral ramp 11 of the bottom wall 10.

Each window 45 further comprises an arcuated oblong portion 47 with a curvature radius, which is centered in the hinge axis of the lateral wall carrying the pin 35 and which is equal to the distance of the respective pin 35 to said hinge axis, said arcuated oblong portion 47 having a width which is slightly

larger than the contour of the pin 35 and smaller than that of the enlarged head 36, said oblong portion 47 of the window 45 having an end which is opened to the inside of the enlarged portion 46 and with a blind opposite end in a position concentric to the position of the respective pin 35 when its larger lateral wall 30 is in the box assembled condition.

With this construction, when a smaller lateral wall 40 is in the box assembled condition and a larger lateral wall 30 is in an assembly position close to the box assembled condition, in which the pins 35 thereof are aligned with the enlarged portions 46 of the respective pair of windows 45 of said smaller lateral wall 40, there is provided the fitting of the pins 35 into the windows 45 and the larger lateral wall 30 is angularly displaced, until the pins 35 thereof reach the blind end of the arcuated oblong portion 47 of the windows 45. Thus, both walls will be locked to each other, with the enlarged head 36 of the pair of pins 35 being seated against the external face of the smaller lateral wall 40, which is traversed by the respective pins 35. However, it should be understood that, in the region of the windows 45, the smaller lateral walls 40 may have their external faces lowered, in order to avoid the enlarged heads 36 of the pins 35 from projecting outwardly from the contour of the box.

Disassembly of the walls is achieved by making movements which are opposite to those described in relation to the assembly of said walls.