Patent Publication Number: US-2023150712-A1

Title: Plastic container with reinforced corner portions

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a National Stage application of International Patent Application No. PCT/IB2021/055295, filed Jun. 16, 2021, which claims the priority of Swiss patent application 798/20, filed Jun. 29, 2020, the disclosure of each of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The invention relates to a plastic container for transporting and storing goods. In particular, it relates to such a plastic container with reinforced corner portions on the outside of the plastic container. 
     BACKGROUND OF THE INVENTION 
     Plastic containers with reinforced corner portions are known. The reinforcement serves to increase the impact resistance of the corners which are exposed in particular to impacts when the containers are moved and stacked. 
     CH 567 968 discloses a bottle crate with reinforced corner portions consisting of triangle-shaped widenings of corner columns on the inside of the crate which are bevelled towards the base of the crate at an angle of 45° to the side walls. 
     EP 2 383 190 discloses a plastic container with a reinforced corner portion consisting of a T-shaped rib extending diagonally outwards from the outside of the corners and over the entire height of the container. 
     In addition, plastic containers are known in the trade which, over part of the height, have a hollow reinforcement on the outside of their corners, which have a small slit-shaped opening at their upper end. 
     SUMMARY 
     Accordance to the present invention, a plastic container having a base and side walls extending vertically from the base to a circumferential top edge is disclosed. In each of its corners where the side walls meet, the container has respective reinforced corner portions located in each case on the outside, due to the fact that the corner portions are of double-walled design. For this purpose, an outer wall extends upwards in each case from the level of the lower edge of the side walls over part of the height of the side walls near the outside of the side walls. As such, the double-walled corner portions have cavities extending continuously from top to bottom over the entire height of the double-walled corner portions, with one or more ribs extending in each case from the outer wall to the outside of the side walls. The ribs thus form a plurality of cavities in each corner portion between the outer walls of the corner portions and the side walls of the container. In particular, the hollow corner portions are open at their upper ends as well as at their lower ends. 
     The design according to the invention of the reinforcing corner portions achieves several advantages in combination, on the one hand during production by injection moulding, and on the other hand during use, in particular during cleaning of the containers. During production, containers of this type are injection moulded in an injection moulding process by means of an injection moulding machine and an injection moulding tool mounted thereon. The moulding tool consists of multiple moulding parts, so that the injection moulded article can also be demoulded after injection and cooling of the plastic. 
     The moulding tool for the container according to the invention consists of an inner moulding tool part for shaping the inner shape and the upper edge of the container, multiple outer moulding tool parts for each of the outer container side walls and a moulding tool part for the base, at the corners of which protruding tool core elements are integrated. These protruding tool core elements are used to form the cavities of the reinforced, double-walled corner portions of the container in the injection moulding process. In the cycle of the injection moulding process, the moulding elements of the multi-part moulding tool are brought together and pressed against each other at high pressure at the mould partitions (also called pinch-offs). Because the provided cavities of the reinforced corner portions according to the invention are continuous, the elongated protruding tool core elements can be supported at their ends on their full cross-sectional area and over their full circumference on the moulding tool parts for the outer side walls when the moulding tool parts are moved together. 
     In prior art containers, the openings of the corner portions are slot-shaped, and the core elements are correspondingly small in circumference. In the present invention, however, the support surfaces of the core elements on the moulding tool parts for the side walls are significantly larger than in the prior art. On the one hand, this has the advantage of reducing wear on the costly injection moulding tool parts. This results from the fact that the cooling of the moulding tool parts is increased due to the enlarged surface area when the mould partition is engaged, i.e. when the core elements meet the moulding tool parts of the side walls (also known as pinch off). As a result, the injection moulding tool parts are available over a longer period of use, which makes the overall production of such containers more cost-effective. 
     On the other hand, the continuous cavities of the corner portions result in a further advantage. When cleaning a plastic container according to the invention by means of water, the containers are washed both on the inside and the outside, wherein the containers are washed upside down, i.e. with the interior facing downwards. Because the cavities of the corner portions are continuous, the washing water can flow directly out of the corner portions without leaving any residue and can be rinsed out completely, and no water is left behind in the cavities. In prior art containers, on the other hand, the cavities are not continuous or are only provided with small openings at the upper end, so that washing water always remains behind and can lead to hygiene problems. 
     The one or more ribs between the outer walls of the double-walled corner portions and the outsides of the side walls divide the space of the corner portions into several smaller cavities, resulting in an extremely stable structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a plastic container according to the invention in perspective from above. 
         FIG.  2    shows the container from  FIG.  1    in perspective from below. 
         FIG.  3    shows the container from  FIGS.  1  and  2    in a top view. 
         FIG.  4    shows the container from  FIG.  3    in cross-section according to A-A in  FIG.  3   . 
         FIG.  5    shows the corner portion according to the invention of the container in an enlarged view from above according to the arrow V in  FIG.  1   . 
         FIG.  6    shows the corner portion from  FIG.  5    in an enlarged view from below according to arrow VI in  FIG.  5   . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG.  1    shows a plastic container  1  according to the invention with a base  2  and short first side walls  3  and long second side walls  4 , which extend perpendicular from the base  2  to a respective upper edge  3 ′ and  4 ′, respectively. The first and second side walls  3  and  4  each meet at corners, the corners having reinforcements on their outer sides facing away from the interior of the container. The reinforced corner portions  5  are of double-walled designed for this purpose, the double-walled corners extending from the base to a predetermined height of the corners; however they extend only over a portion of the height of the container rather than to the top of the container. Reinforcement over a portion of the height is generally sufficient for impact resistance of the container. 
     The double-walled corner portion  5  consists, on the one hand, of the outer wall of the side wall  3  and  4 , respectively and, on the other hand, of a second wall  6  which extends over a predetermined height and width. In the view from above according to  FIG.  1   , in a corner portion  5 , cavities  7  are shown in each case between the side walls  3 ,  4  and the additional outer wall  6 . According to the embodiment in  FIG.  1   , the cavities  7  are designed in particular to be completely open at the top, i.e., they are not reduced in size in any way, but their opening at the upper end has the maximum size. 
     The view from below in  FIG.  2    of the same container in turn shows the cavities  7  of the corner portions  5 , with the cavities  7  also being open at the bottom. Here, too, the openings have a maximum size at the bottom. The cavities are thus continuous from top to bottom with openings of maximum size. 
       FIG.  3    shows the container in a view from below with the reinforced corner portions  5 , each with multiple ribs  8  and  8 ′, which subdivide the corner portions into multiple cavities  7 . 
       FIG.  4    shows the cavities  7  continuously extending from bottom to top in a cross-section according to A-A in  FIG.  3   . The subdividing ribs  8  and  8 ′ extend over the entire height of the reinforced corner portions  5 . 
       FIGS.  5  and  6    show the corner portions in enlarged detail in a perspective view from above and below, respectively. In particular, the lateral ribs  8  on the side walls  3  or  4  are shown, which are at right angles with respect to the side walls  3  or  4  and the walls  6  of the reinforced corner portions. In each corner portion, another rib  8 ′ extends in each case diagonally inwards from the corner of the outer walls  6  to the corner of the container where side walls  3  and  4  meet. The continuous ribs  8  at right angles to the side walls and the diagonal ribs  8 ′ divide the double-walled space of the reinforced corner portions  5  into the multiple continuous cavities  7 .  FIGS.  5  and  6    also show how each of the ribs  8  and  8 ′ extend over the entire height of the double-walled corner portions, thus optimizing the reinforcement of the corner portions  5 . 
     Although various embodiments of the present invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.