EP0575394B1 - Container arrangement - Google Patents

Abstract

A container arrangement comprises a plurality of stackable plastics containers (12) which have a container base (30) and four side walls (24, 26) which project above the container base, are connected to each other at rounded corners (22) and form a common upper rim (34). The container arrangement can support high stacking and transport loads despite the thin walls of the containers. To this end, load-bearing columns (18, 20) made of the same plastics material as the container, which project essentially vertically above the container base, are monolithically incorporated on the inner wall of the container in the region of the corners (22) of the container and the side walls (26). The lower end of the load-bearing columns (18, 20) is connected to the container base (30), while the upper faces (32, 32') are arranged at a distance (d) below the upper edge (34) of the container and form a supporting surface for a second container (12) placed on top of the first and whose base (30) engages in the inside of the first container. The container is made of a material consisting of a high-strength reaction plastic based on polydicyclopentadiene.

Description

The invention relates to a container arrangement according to the preamble of claim 1, as e.g. from CH-A-572 418 is known.

In the material flow of industrial companies, workpieces are often delivered in containers, stored temporarily and brought to the respective workplace. For transport and storage purposes, these containers must be stackable to form container arrangements and must therefore be provided with stacking edges in the area of their lower and upper edges. The known stacking edges are formed all around, the upper edge of the container also forming a supporting edge for the stacking container located above. In adaptation to the usual pallet size, the stacking containers are mostly designed as flat containers with a base area of 1,200 x 800 mm, whereby for reasons of strength only containers made of metal (steel or aluminum) have been used up to now. It was perceived as a disadvantage that the containers are relatively heavy, often heavier than the goods to be transported. In order to avoid this disadvantage, it has already been proposed to produce the containers predominantly from plastic, which, however, had to be reinforced with metal or wooden parts in the given dimensions.

Proceeding from this, the object of the invention is to develop a container arrangement with plastic containers which can be stacked one on top of the other and which, despite the thin-walled and therefore lightweight construction, can absorb relatively high stacking and transport loads.

To achieve this object, the combination of features specified in claim 1 is proposed. Further advantageous refinements and developments of the invention result from the dependent claims.

The invention is based primarily on the idea that, in the case of thin-walled plastic containers with a large base area, additional precautions are required in order to be able to accommodate the high stacking and transport loads which occur during transport and to avoid impermissible deflections and connections under uneven loading. In order to achieve this, it is proposed according to the invention that on the inside of the container in the region of the container corners substantially vertically projecting load columns are integrally integrated in the plastic material of the container, the lower end of which is connected to the container bottom and the upper end faces at a distance below the upper edge of the container is arranged and forms a support surface for a further container engaging with its bottom into the interior of the container from above. According to a preferred embodiment of the invention, at least one side wall is on the inside of the container Distance from the corners of the container integrally integrates a further load column, which protrudes substantially vertically above the bottom of the container, into the plastic material of the container, the lower end of which is connected to the bottom of the container and the upper end faces are arranged at a distance below the upper edge of the container and an additional contact surface for the other forms at the top with its bottom engaging in the container interior. The further load-bearing columns are expediently arranged centrally in two opposite broad side walls of the container, which is essentially rectangular in plan.

A further advantageous embodiment of the invention provides a concave stacking step which is molded into the outside of the container bottom and is open at the bottom and outside, the height of which is somewhat greater than the distance between the upper edge of the container and the end face of the load column and the depth of which corresponds approximately to the side wall thickness. In order to save material, a circumferential convex bottom edge step corresponding to the stacking step can be arranged on the inside of the container. The load-bearing columns should have at least a thickness corresponding to the side wall thickness, a thickness corresponding to the depth of the base edge step having proven to be particularly expedient.

It is also important to ensure that the relatively thin-walled container side walls, particularly in the corner area, are sufficiently dimensionally stable to prevent twisting or bending to avoid. In order to achieve this, it is proposed according to the invention that the load-bearing columns arranged in the corner region have a preferably flat boundary surface oriented obliquely to the adjacent side walls towards the interior of the container. The load-bearing columns expediently form a cylinder segment molded into the cylindrically rounded corners. A further improvement in this regard is achieved if the additional load columns arranged in the region of the side walls have a trapezoidal or part-circular cross section which tapers towards the interior of the container.

With the measures according to the invention it is achieved that the stacking and transport forces are directed downward exclusively via the load-bearing columns, while the side walls mainly have to absorb transverse loads due to the existing positive locking, the load-bearing columns additionally taking on the function of reinforcing ribs within the side walls. The side walls and the bottom surfaces can thereby be made relatively thin-walled. The investigations carried out in this connection have shown that the side wall thickness should nevertheless be chosen to be greater than, preferably twice as large as, the base wall thickness. With a base area of approximately 1 m² and a side wall height of 10 to 20 cm, a bottom wall thickness of 2 to 4 mm and a side wall thickness of 4 to 8 mm have also proven sufficient for large payloads to be carried.

gewählt werden, wobei α den Entformwinkel in Grad und w die Wandstärke der Seitenwand und/oder der Traglastsäule bedeuten. Die niedrige Behälterhöhe hat andererseits den Vorteil, daß die Entformschräge relativ klein sein kann, der Entformwinkel also vorteilhafterweise zwischen 0,4° und 1° gewählt werden kann.The load columns according to the invention only fulfill their function if they are vertically one above the other. If one takes into account that the side walls of the containers, which are made of plastic, preferably in the RIM process (Reaction Injection Molding), must have a draft angle, the load-bearing columns only come into play at relatively low side wall heights, which are appropriate for the given floor dimensions of approx. 1 m² is less than 1/6, preferably 1/8 to 1/12 of the side wall length. In any case, the side wall height h must

$\text{h <15 w / α}$

can be selected, where α is the draft angle in degrees and w is the wall thickness of the side wall and / or the load-bearing column. The low container height, on the other hand, has the advantage that the draft angle can be relatively small, so that the draft angle can advantageously be chosen between 0.4 ° and 1 °.

Since, on the other hand, there may also be a desire for higher containers, it is proposed according to a preferred embodiment of the invention to additionally produce a bottomless container frame made of plastic which has at least three, preferably four, side walls which are connected to one another at frame corners and form a common circumferential upper edge and lower edge, its side walls on the inside of the container in the area of the frame corners and, if necessary, at a distance from the frame corners, integrally integrated load-bearing columns in the plastic material, the lower end of which extends into the vicinity of the lower edge and whose upper end face is arranged at a distance below the upper edge of the frame and a support surface for one from above with its floor or its lower edge forms a container or frame that engages in the inside of the frame, and which contains a circumferential stacking step which is molded on the outside in the area of the lower edge of the frame and is open to the outside, the height of which is slightly greater than the distance between the upper edge of the frame and the load-bearing column end face and the depth of which is approximately the same as the side wall thickness and / or Thickness corresponds to the load column connected to it at its lower end, the container frame with its stacking step being placed on the upper edge of a container or another container frame and connected to it, preferably glued. To improve stability and for a rigid connection, a connecting bar can be attached from the inside in the area of the load-bearing columns, eg screwed on or glued on. The screw holes can be molded in during the manufacture of the frame or subsequently drilled. All connecting elements, including the strips and screws, are expediently made from the same material in order to avoid problems with thermal expansion and to ensure easy recycling.

The bottomless container frames and containers can be produced with the same molds if an interchangeable insert in the form of a plate adapted to the base wall thickness is used for the base part. A major advantage of this design is that containers of different heights can be produced with a single tool. Another advantage is that the tall containers, which are composed of relatively low container elements, have vertical side walls in the assembled state, which are structured somewhat jagged only within the wall. In the overall production of a correspondingly high container, no vertical side walls would arise due to the necessary draft angles and thus usable space and strength would be lost.

According to a further preferred embodiment of the invention, in the region of each side wall there is at least one recessed grip which is molded into the side wall and the container bottom, is open on the outside of the container to the side and downwards, and is closed towards the inside of the container. To save material, the recessed grip can be formed by a bulge of material protruding from the side wall and from the bottom of the container into the interior of the container. The recessed grip, which is open at the bottom, also has the function of a locking element and a stiffening element, it being particularly advantageous if the grip recesses are each arranged centrally between two adjacent load columns. Appropriately point the Grip recesses have a trapezoidal outline which is open at the bottom and widens, the side flanks of the trapezoidal grip recesses being inclined and the upper flank being aligned perpendicularly to the side walls.

It has proven to be particularly advantageous if the features listed above are realized in a container made of a reaction plastic based on polydicyclopentadiene. This plastic has excellent strength properties which meet the purpose of the invention in a special way.

With the measures according to the invention, it is in principle also possible to stack containers with different, preferably halved bottom dimensions on top of one another, if it is ensured that the central load column serves as an extension of the corner load columns of the smaller containers. Since the smaller containers also have to absorb smaller forces, and because of the additional partition a stiffening is achieved, the existing load columns are sufficient for support. The middle load column just has to be made wide enough so that a direct load transfer via the load columns is possible.

On the other hand, large containers can also be stacked on smaller ones. This can be done in that a suitably shaped between the containers Cover plate is placed. Another possibility is that the bottom of the container has a gutter which extends between two opposite load-bearing columns arranged in the center of the side walls and is open at the bottom and corresponds in depth to the height of the stacking step, and that the container is placed on two others close together arranged, preferably half the size of the container is stacked so that it overlaps the upper edges of the facing side walls of the other containers with its groove and is supported with its centrally arranged load columns on the corner load columns of the other containers below.

According to an advantageous development of the invention, a pallet is provided for positively receiving a container or stack of containers, it being possible to arrange cams which protrude on the surface of the pallet and engage positively with the recessed grips of a container seated thereon. The cams expediently have a smaller height than the recessed grips, so that the intended function of the recessed grips can also be used in the lowest container. In order to make the pallets stackable as such, open-ended cutouts with positive teeth can be provided on the underside of the pallets with a cam located underneath.

In principle, it is also possible to place the pallet on the bottom of the container molding one of the containers in one piece. This means that the cutouts for a forklift are already integrated on the container in question.

According to a further advantageous development of the invention, a container lid is provided which engages with its underside in the container and rests on the load-bearing columns and which can have at least one trough which is open at the top for the positive adjustment of a pallet or a container.

Furthermore, an insert bed adapted to the inner contour of the container is expediently provided, preferably made of self-supporting foam plastic, which in turn has at least one recess adapted to the contour of a transport object and should be stackable and palletable with other insert beds even without the container, while producing a positive connection.

Fig. 1

eine Stirnseitenansicht einer Behälteranordnung mit drei palettierten Behälterstapeln;

Fig. 2

eine Draufsicht auf einen Behälter;

Fig. 3

einen Schnitt entlang der Schnittlinie 3-3 der Fig. 2;

Fig. 4

einen Schnitt entlang der Schnittlinie 4-4 der Fig. 2;

Fig. 5

einen Schnitt entlang der Schnittlinie 5-5 der Fig. 2;

Fig. 6

einen Schnitt entlang der Schnittlinie 6-6 der Fig. 2;

Fig. 7

einen Ausschnitt aus Fig. 2 mit Griffmulde;

Fig. 8

einen Schnitt entlang der Schnittlinie 8-8 der Fig. 7 mit zusätzlichem Querschnitt durch die Seitenwand im Bereich der Griffmulde;

Fig. 9

einen Schnitt entsprechend Fig. 3 durch einen doppelt hohen Behälter;

Fig. 10

eine Innenansicht des aufgeschnittenen doppelt hohen Behälters in Richtung der Behälterecke.

The invention is explained in more detail below with reference to an exemplary embodiment shown schematically in the drawing. Show it

Fig. 1

an end view of a container arrangement with three palletized container stacks;

Fig. 2

a plan view of a container;

Fig. 3

a section along the section line 3-3 of Fig. 2;

Fig. 4

a section along the section line 4-4 of Fig. 2;

Fig. 5

a section along the section line 5-5 of Fig. 2;

Fig. 6

a section along the section line 6-6 of Fig. 2;

Fig. 7

a section of Figure 2 with recessed grip.

Fig. 8

a section along the section line 8-8 of Figure 7 with an additional cross section through the side wall in the region of the recessed grip.

Fig. 9

a section corresponding to Figure 3 through a double tall container.

Fig. 10

an interior view of the cut double tall container in the direction of the container corner.

In the container arrangement shown in FIG. 1, three container stacks, each with eight flat plastic containers 12, a pallet 14 and a container lid 16, are stacked one on top of the other. The containers 12 stacked one above the other engage with their bottom part in a form-fitting manner in the container located underneath, while the bottom container 12 of each stack has a positive fit and thereby rests non-slip on the associated pallet 14. In addition, each lid 16 positively engages in the uppermost container of a stack 10 and forms an adjustment trough (not shown) for the pallet 14 located above it. The stacking and transport load is diverted downward via load-bearing columns 18, 20 in the container side walls.

As can be seen in particular from FIGS. 2, 4 and 5, the load-bearing columns 18 are arranged in the region of the rounded corners 22 between adjacent narrow side walls 24 and broad side walls 26, while the load-bearing columns 20 are formed in the central region of the opposite broad side walls 26. The load-bearing columns 18 have the shape of a cylinder segment delimited after the interior of the container by a flat boundary surface 28, while the load-bearing columns 20 are trapezoidal in cross-section. The load-bearing columns 18, 20 are connected at their lower end directly to the container base 30 and end at their upper end face 32, 32 ′ at a small distance d below the upper container edge 34. Furthermore, the containers have a circumferential, concave stacking step 36 on their lower edge. the height of which is slightly greater than the distance d and which ensures that the stacked containers 12 form-fittingly overlap the respective upper edge 34 and support the base 30 on the end faces 32, 32 'of the load-bearing columns 18, 20 of the respective container below interlock. The stacking level 36 forms a circumferential bottom edge step 40 pointing towards the inside of the container for reasons of material savings. Furthermore, it can be seen from the sectional view in FIG. 3 that the container base 30 has only approximately half the wall thickness of the side walls, while the thickness of the load-bearing columns corresponds approximately to the side wall thickness (FIG. 4 and 5).

In the narrow side walls 24 and the wide side walls 26 there are one or two recessed handles 42, which are open both downwards and laterally outwards and are closed by a bulge 44 pointing towards the inside of the container. The bulges 44 also form an effective stiffening of the thin-walled side walls 24, 26. As can be seen in particular from FIG. 8, the recessed grips have a trapezoidal outline which widens downward in the side view, the side flanks 46 additionally projecting obliquely beyond the associated side walls towards the inside of the container, while the upper flank 48 runs parallel to the bottom 30 of the container. On the pallets 14, latching cams 50 can be provided for a positive connection with the stack of containers, which interlock positively with the handle recesses 42 of the bottom container 12.

The container shown in FIGS. 9 and 10 is composed of two parts, a lower container 12 and one with its lower edge 60 placed on its upper edge 34 and by means of an adhesive layer 62 this glued bottomless container frame 12 '. The container frame 12 'has in the region of its lower edge 60 a stacking step 36 and a circumferential convex bottom edge step 40 corresponding to the stacking step and is supported with its load-bearing columns 18 on the load-bearing columns of the lower container 12. For further stiffening, the container 12 and the container frame 12 'are rigidly connected by connecting strips 66 screwed onto the inside of the load-bearing columns 18 by means of screws 64. The connecting strips 66 and the screws 64 suitably consist of the same plastic material as the container 12 and the container frame 12 '.

From the lower part of FIG. 9 it can be seen that the container has a height h, a side wall thickness w and a draft angle α. The thickness of the load columns essentially corresponds to the wall thickness w. The demoulding angle α is chosen to be so small at approximately 0.5 ° that an almost vertical outer wall with a small step is formed in the area of the adhesive joint 62.

In summary, the following can be stated: The invention relates to a container arrangement with a plurality of containers 12 made of plastic which can be stacked one on top of the other and which have a container base 30 and four side walls 24, 26 which project over the container base and which are connected to one another at rounded container corners 22 and form a common peripheral container edge 34 . On the inside of the container in the area of the container corners 22 and the side walls 26, load columns 18, 20 projecting substantially vertically above the container base 30 are integrated in one piece in the plastic material of the container. The lower end of the load-bearing columns 18, 20 is connected to the container base 30, while the upper end faces 32, 32 ′ are arranged at a distance d below the upper container edge 34 and a bearing surface for a further container 30 that engages with the base 30 into the interior of the container from above 12 forms. In order to be able to absorb high stacking and transport loads despite the thin-walled container design, this container arrangement is designed in accordance with the characterizing part of claim 1. The container material consists of a high-strength reaction plastic based on polydicyclopentadiene.

Claims (20)

1. Container arrangement having a plurality of stackable plastic containers (12), which have a container base (30) and at least three, preferably four side walls (24, 26) projecting from the container base (30), connected to one another at container corners (22) and forming a common circumferential container top edge (34), having on the inside of the side walls of the container, in the region of the container corners (22), load-bearing columns (18) projecting substantially at right angles from the container base (30) and integrally incorporated in the plastic material of the container, of which columns the bottom end is connected to the container base (30) and the top end face (32) is disposed at a distance (d) below the container top edge (34) and forms a supporting surface for a further container (12) engaging with its base (30) from above into the container interior, characterized in that the side walls (24, 26) from the base up diverge outwards at a mould release angle (α), and that the side wall height h is less than 15 w/α, in which α is the mould release angle in degrees and w is the wall thickness of the side wall (24, 26) and/or of the load-bearing column (18, 20).
2. Container arrangement according to claim 1, characterized in that the mould release angle (α) is 0.4° to 1°.
3. Container arrangement according to claim 1 or 2, characterized in that the load-bearing columns (18, 20) have a thickness corresponding to the side wall thickness (w).
4. Container arrangement according to one of claims 1 to 3, characterized by an outwardly open, circumferential stacking shoulder (36), which is formed into the outside of the container base (30), whose height is slightly greater than the distance (d) between the container top edge (34) and the load-bearing column end faces (32, 32') and whose depth roughly corresponds to the side wall thickness.
5. Container arrangement according to claim 4, characterized in that a circumferential, convex base rim shoulder (40) corresponding to the stacking shoulder (36) is disposed on the inside of the container.
6. Container arrangement according to claim 5, characterized in that the load-bearing columns (18, 20) have a thickness corresponding to the depth of the base rim shoulder (40).
7. Container arrangement according to one of claims 1 to 6, characterized in that the distance (d) between container or frame top edge (34) and load-bearing column end face (32, 32') is 3 to 8%, preferably 5%, of the side wall height (h).
8. Container arrangement according to one of claims 1 to 7, characterized in that the load-bearing columns (18) disposed in the corner region present, towards the interior of the container, a flat boundary surface (28) aligned obliquely relative to the adjacent side wall surfaces (24, 26).
9. Container arrangement according to claim 8, characterized in that the load-bearing columns (18) disposed in the corner region form a cylinder segment formed into the cylindrically rounded-off corners.
10. Container arrangement according to one of claims 1 to 9, characterized in that disposed on the inside of at least one side wall (26) of the container, at a distance from the container corners (22) is a further load-bearing column (20), which projects substantially at right angles from the container base and is integrally incorporated in the plastic material of the container (12), of which column the bottom end is connected to the container base (30) and the top end face (32') is disposed at a distance (d) below the container top edge (34) and forms a supporting surface for the further container (12) engaging with its base (30) from above into the container interior.
11. Container arrangement according to claim 10, characterized in that the further load-bearing columns (20) are disposed preferably centrally in two opposing broad side walls (26) of the container (12), which has a substantially rectangular surface area.
12. Container arrangement according to claims 10 or 11, characterized in that the further load-bearing columns (20) disposed in the region of the side walls (26) have a cross-section in the shape of a graduated circle or a trapezium tapering towards the container interior.
13. Container arrangement according to one of claims 1 to 12, characterized in that the side wall thickness is greater than, preferably twice as great as, the base wall thickness.
14. Container arrangement according to one of claims 1 to 13, characterized in that the side wall height (h) is less than 1/6, preferably 1/8 to 1/12 of the side wall length.
15. Container arrangement according to one of claims 1 to 14, characterized in that, given a surface area of around 1 m² and a side wall height (h) of 10 to 20 cm, the base wall thickness is 2 to 4 mm and the side wall thickness is 4 to 8 mm.
16. Container arrangement according to one of claims 1 to 15, characterized by an additional, base-free container frame (12') made of plastic, comprising at least three, preferably four side walls (24, 26) which are connected to one another at frame corners (22) and form a common circumferential frame top edge (34) and frame bottom edge (60), load-bearing columns (18) which are integrally incorporated in the plastic material of the container and project at the inside of the side walls (24, 26) of the container in the region of the frame corners (22) and whose bottom end extends as far as into the vicinity of the bottom edge and whose top end face is disposed at a distance (d) below the frame top edge (34) and forms a supporting surface for a container (12) or container frame (12') engaging with its base or bottom edge from above into the frame interior, and an outwardly open, circumferential stacking shoulder (36), which is formed in the region of the frame bottom edge (60) into the outside thereof, whose height is slightly greater than the distance (d) between frame top edge and load-bearing column end face (32) and whose depth approximately corresponds to the side wall thickness (w) and/or the thickness of the load-bearing columns (18) connected to its bottom end, the container frame (12') being placed with its stacking shoulder (36) onto the top edge (34) of a container (12) or another container frame (12') and being connected thereto, and the side wall height (h) of the container frame (12') being less than 15 w/α, in which α is the mould release angle of the container frame in degrees and w is the wall thickness of the side wall (24, 26) and/or of the load-bearing column (18, 20).
17. Container arrangement according to claim 16, characterized in that the container frame (12'), on the one hand, and the container (12) or the other container frame (12'), on the other hand, are glued to one another in the region of the stacking shoulder (36).
18. Container arrangement according to claims 16 or 17, characterized in that connection strips (66) are mounted, preferably screwed or glued, from the direction of the container interior onto the load-bearing columns (18, 20) of the container (12) and container frame (12') which are to be connected to one another.
19. Container arrangement according to claim 18, characterized in that the connection strips (66) and possibly the screws (64) used to fasten the strips are made of the same plastic material as the container (12) and the container frame (12').
20. Container arrangement according to one of claims 1 to 19, characterized in that the container (12) is made of a reaction plastic based on polydicyclopentadiene.

Images