SK92596A3 - Small box made of plastic material - Google Patents

Abstract

A small cage or box (10) made of plastic material, is intended particularly for the packaging and transportation of fruits and vegetables, and is pierced with holes (20) in its bottom (12) and sides (14, 16). Each hole (20) is surrounded by a thermoset projection part (22) which is oriented outwards. In at least two of the corners of the bottom (12), a projection part (22a) surrounding a hole (20a) is intended to penetrate in a vertical passage going through a corner pillar (18) of a lower adjacent box, when a plurality of such small boxes are superimposed. At least in the bottom (12) of the box, bosses (24) or a bulging distributed between the projection parts (22) are formed by thermal shaping inwards of the small box.

Description

Technical field

The invention relates to a plastic crate, in particular for storing and transporting fruit and vegetables.

BACKGROUND OF THE INVENTION

Various types of crates of wood, cardboard or plastic are known in the art. Together, wood and paperboard crates suffer from many disadvantages.

The first of these disadvantages is their water permeability. In the case of crates made of paperboard, the water permeability is particularly sensitive as their mechanical strength is significantly reduced in the presence of moisture. In all cases the stated water permeability. wood and cardboard crates forces storage for _the pravlek for covered storage space. In addition to this. This disadvantage significantly changes the weight of the packaging of the goods determined by each crate as opposed to the Statutes of Load which prescribe a fixed-set tare.

A further disadvantage of wood and paperboard crates results from the large number of components from which the crates are made. For this reason, apart from the wood or paperboard which forms the basic component of such crates, their mounting requires the use of staples and / or glue. In addition, they generally contain an impregnating agent against moisture, the function of which is to minimize their degree of water permeability. In addition, paper labels are often affixed to wooden crates. The abovementioned amount of components of wood and paperboard crates complicates their production, which in turn leads to an increase in production costs. In addition, the operations necessary for the destruction of such crates after use with respect to the recycling of the materials from which their constituent components are made are, as a result of the above, much more complicated.

The third disadvantage, common to wood crates, is: cardboard cardboard crates. Their flammability and the consequent danger that arises during their storage, irrespective of whether the crates are full or empty.

Finally, the production of said wood and paperboard crates leads to a large consumption of wood, which is ecologically very disadvantageous.

Stacking of crates during storage or transportation It is much more obstructed due to the ratio of crate bottom thickness to perpendicular corner uprights.

In addition to the disadvantages mentioned above, common to both wood and paperboard crates, the peculiarities of the characteristics of each of the materials from which the crates are made are discussed.

in the case of wood crates, the rough surface structure of the untreated wood from which they are formed

Individual strips, damage products stored in these crates, especially in the case of storage of fruit.

In the case of paperboard crates, as already mentioned above, their mechanical properties deteriorate considerably in the presence of moisture. It should be noted that this moisture can be moisture coming from the environment as well as from products in containers stored and transported.

A further disadvantage, inherent in paper-based crates and resulting from the above, is the insufficient ventilation of the products in such crates stored and transported. Ξ caused limited mechanical strength of paperboard crates not perforated in their walls. As a result, cardboard cartons for the storage and transport of certain products that require efficient ventilation are unusable.

Plastic crates solve virtually all of the above-mentioned problems, which are common to both wood and paperboard crates. However, these crates are currently manufactured by injection molding of plastics, i.e. using a non-continuous manufacturing process which results in a large increase in production costs.

The use of injection molding also results in crate walls having a grid-like or grid-like structure that can cause damage to stored and transported products, particularly in the case of fruit. As a result, the walls of the crate are rigid and inflexible, which can lead to the impression of stored and transported products when placed in the crate.

Finally, the construction of injection molded plastic crates makes their overall dimensions in the vertical direction when stacked on shipping pallets comparable to those of wood crates.

Patent application WO-A-92/09488 discloses a method according to which plastic crates can be manufactured by extrusion. Said crates are formed by extrusion of at least one plastic part. In the bottom forming section and the four walls of the crate, said plastic part has a strip shape in which irregularly shaped openings are formed. A projection is formed by thermoforming around each of the apertures in the belt.

Consequently, the plastic crates thus formed do not suffer from the disadvantages of the plastic crates produced by injection molding. The continuous production of crates by means of extrusion makes it possible to significantly reduce production costs, which can be reduced below the corresponding production costs necessary for the manufacture of crates of wood and paperboard. In addition, the construction of the crates provides their walls with some elasticity so that the stored and transported products are not damaged. Thus, the overall dimensions of the stack of containers in the vertical direction can be reduced compared to the stack of containers made of injection molded wood or plastic. This makes it possible to achieve an increase in the filling level of about 10 percent.

The openings and projections surrounding the openings formed in the crates, as suggested by patent application WO-A-98/09488, cause adequate and sufficient ventilation of stored and transported products while contributing to increasing the mechanical strength of the crates.

However, the products stored and transported in such crates may be damaged by the edges or edges of the openings which are formed in the walls and bottom of the crate and the leakage of water and any other liquid present in the crates is not reliably ensured. transported products. In addition, it is not possible to completely avoid the possible tilting or sliding of said crates when placing them on the conveyor. In addition, as with all crates known in the art, crates formed according to the method described in patent application WO-A-98/09488 can be positioned relative to each other during stacking.

SUMMARY OF THE INVENTION

The present invention relates to a plastic crate, the main features of which are achieved by the method described in patent application WO-A-92/09488 and whose original exterior treatment allows to eliminate any risk associated with damage to stored and transported products, efficiently ensures liquid leakage, any dangerously skewing of the crates when placed on the conveyor and facilitates positioning of the crates relative to each other during stacking, without increasing the manufacturing cost of their manufacture while maintaining all other advantages associated with the use of plastic crates.

According to the present invention, this result is achieved by means of a plastic crate comprising a rectangular bottom, four walls and four hollow corner uprights, wherein at least the rectangular bottom and walls are formed of a plastic strip having openings each surrounded by a thermoforming formed by a protrusion, characterized in that said protrusions are oriented outwardly from the crate and at least two of these protrusions are formed in the bottom of the crate, in an extension of at least two of the four hollow corner uprights to allow the hollow corner uprights to penetrate into the lower bottom lying crate.

By using certain plastics materials which are intended for use in the manufacture of such crates, such as polypropylene, polyvinylchloric, etc., the formation of protrusions in the bottom and walls of the crate by thermoforming leads to deformation of these planar parts in the direction of thermal influence, i.e. . When stacking crates, therefore, the products stored in any crate can be damaged by the edges or edges of the holes formed in the bottom of the crate lying above it. In order to eliminate this disadvantage, the plastic strip, at least in the bottom of the crate, has at least one non-perforated, thermoformed curvature located between the protrusions and oriented towards the interior of the crate.

A single curvature may be provided over the entire surface area of the crate bottom or walls between the protrusions, as the case may be, or several convexities may be disposed between said protrusions.

In addition, the walls of the crate are preferably elastic so that the products in the crate are not exposed to the impression during the insertion thereof in the crate.

In order to increase the mechanical strength of the walls of the crate, it is preferably provided with an upper flange. bent outwards from the crate at an angle of at least about. 90 degrees.

In this case, the upper flanges are preferably interrupted by the rigid front surface of the hollow corner uprights tall so that vertical angular elements can be placed in the corners of the crates during stacking on pallets and in carrying out the usual working procedure.

According to a feature of the present invention, the container is preferably made of a transparent or translucent plastic. By means of this characteristic, it is possible to control the products stored in the stack of pallets relatively easily and, in particular, to determine the type of product, its size, current status and the like, which is a substantial choice compared to the known crates of the prior art.

During the transport of a product such as lettuce, it is desirable to protect such a product from the effects of photosynthesis. This leads to the use of an opaque plastic material, the opacity of which is relatively easy to achieve by, for example, tinting or coloring the translucent plastic without the necessity of placing tin-colored protective paper.

In a preferred embodiment of the present invention, the walls and hollow corner uprights of the crate are formed by cutting and bending from one of the same extruded plastic vial.

Figures and drawings

A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawing, wherein:

Fig. 1 is a perspective view showing the plastic crate of FIG. of the present invention,

Fig. 3 is an enlarged vertical cross-sectional view of the plastic crate shown in FIG. 1

Fig. 3 is a schematic and partial vertical sectional view showing three plastic crates according to the present invention when stacked; and

Fig. 4 is an axonometric view showing a plurality of plastic crates according to the present invention stored on a pallet and fastened on their outer corners of the stack by means of vertical angular elements.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 By means of reference numeral 10, a container according to the invention is generally indicated and is made entirely of plastic. The crate is preferably made by extrusion and / or calendering, for example, from two extrusion-formed parts in a manner comparable to the method suggested in the above-mentioned WO-A-92/09488. Alternatively, the crate 10 can be made by extrusion and / or calendering only of other cut, perforated, thermoformed, bent, and welded planar waist panels.

The plastic crate shown in FIG. 1 consists essentially of a planar rectangular bottom 12 of four planar rectangular walls comprising two side walls 14 and two end walls 16 and four hollow corner uprights 18

The side walls 14 are parallel to each other and extend at right angles from the two opposite side edges of the rectangular bottom 13 of the crate. Similarly, the front walls 16 are parallel to one another and extend at right angles to the front edges of the rectangular bottom 12. The rectangular bottom 13 and the walls 14, 16 are made of a flat sheet of plastic of limited thickness (e.g., about 0.8 mm to 2 mm). ).

If desired, the height of the side walls 14 of this type of crate may be smaller (as shown in Fig. 1) or equal to the height of the front walls 16.

The hollow corner uprights 18 extend vertically from the four corners of the rectangular bottom 12 of the crate along the connection between the side walls 14 and the end walls 16 at a length equal to the length of these walls. The corner uprights 18 are hollow, i.e. they are provided in a transverse section along their entire length with a vertical icon channel which allows to reduce the weight and hence the total amount of plastic needed to manufacture the crate, as well as the associated manufacturing costs.

Each of the rectal section of the hypotenuse may or slightly of this rectangular triangle, the hollow corner uprights shape rectangular be rectilinear as it is curved toward having a horizontal triangle as shown in FIG. 1, interior. The two walls which are at right angles to each other are in contact with the walls 14, 16 in the corresponding corner of the crate. In the embodiment shown in FIG. 1, the hollow corner uprights 18 are formed by bending one and the same strip of plastic, from which the rectangular bottom 12 and the walls 14, 16 of the crate are also made.

Taking into account the small thickness of the plastic strip from which at least the rectangular bottom 18 and the walls 14, 16 of the crate are made, said planar parts have a certain flexibility or elasticity. As a result, products such as fruits stored in such a crate are not exposed to the impression. In particular, it is the walls of the crate which either distort or do not distort the products stored therein.

The rectangular bottom 18 and the walls 14, 16 of the crate 10 according to the present invention are provided with transverse openings 30 whose shape, dimensions and layout can vary over a very wide range. In the embodiment shown in FIG. 1 and 3, the apertures 30 are circular and spaced in a triangular mesh over the entire surface area of the rectangular bottom 13 and the walls

On at least one of the walls 14, 16 of the crate, a non-perforated area is preferably provided in order to be able to mark the crate, for example by screen printing. This eliminates the need to attach additional material to the plastic from which the crate is made.

As shown in more detail in FIG. 3, each of the apertures 30 is surrounded by a protrusion 48, which is formed by thermoforming a plastic strip of which the rectangular bottom 13 and the walls 14 16 are made. In particular, the protrusions 88 are oriented outwardly from the crate with respect to the planes formed by the rectangular bottom and the walls of the punch. In the case where the apertures 80 are circular, the protrusions 83 have, for example, a truncated cone shape. However, any shape may be used so as not to extend the claimed scope of the present invention.

Regardless of whether the strip is a plastics material, from which a rectangular bottom 12 s is formed. the crate walls 14, 16, obtained by injection molding, calendering or pressing, the protrusions 22 are always formed by thermoforming so as to achieve prestressing of the plastic. The apertures 20 and projections 22 surrounding these apertures provide a variety of functions.

The first of these features is the fittest products in the crates stored in and transported in them. It will be appreciated from the above that this ventilation can be provided on the basis of a particular requirement, since the shape, size and spacing of the apertures 40 can be varied over a wide range so that the mechanical strength of the crate is not affected in any way.

A second function, performed by the projections 52 surrounding the apertures 20, is to reinforce the strip from which the rectangular bottom and walls of the crate are formed. This reinforcement is particularly important in the case of the rectangular bottom of the crate, the deformation of which during storage of the products must not be too great in order not to damage the fruit or vegetables stored in the lower crate by the edges of the openings 20 when stacking the crates. In contrast, said stiffening of the walls 14, 16 must not be too great in order not to reduce adequate flexibility or elasticity by means of which the possible squeezing of the fruit is eliminated. To this end, the density of the openings 80 will generally be greater in the rectangular bottom 13 than in the walls 14. 16.

Another function results from the orientation of the protrusions 83 outwardly of the crate. This characteristic, however, ensures that the products stored in the crate do not come into contact with the edges of the openings 30. This fact eliminates any possibility of damaging the products with said edges. It should be understood that the shapes and dimensions of the apertures 30 may vary and are a function of the kind in the crate of the product being transported, in particular a function of the size of said product so that the above mentioned risk of product damage is completely eliminated.

Holes 30 and a surveyor. the outwardly extending protrusions 33 surrounding the openings permanently secure and facilitate the flow of water and any other liquids, such as floss, which are used to treat oats and vegetables are essential for their preservation.

the edges of the openings 30, the protrusions 33 in the rectangular formed at the bottom 13, the elimination of the

In addition to the other ends, the stacking of crates at their conveyors is mined. This is significant because storage of fruit usually takes place on conveyor belts and its absence could lead to the risk of leaning or crumbling crates.

In addition, the presence of the apertures 80 reduces the weight of the crates and at the same time the amount of plastic needed to produce them, resulting in a reduced production cost.

As shown in FIG. 3, an opening 20a is provided at each corner of the rectangular bottom 18 of the crate. The aperture 20a is located in the extension of the vertical channel formed in the hollow corner upright 18 extending from said year. This opening 20a allows water and other possible liquids to which the crates are exposed to penetrate through the uprights and to escape from them by gravity.

Like the apertures 20, at least two of the four apertures 20a disposed at the corners of the rectangular bottom 12 are surrounded outwardly, i.e. by the rectangular bottom 12 facing the projections 22a.

As shown schematically in FIG. 3, this arrangement makes it possible to position and hold the crates 10 when stacked one above the other. In this state, the projections 22a of each of the crates 10 enter the vertical channel formed in each of the hollow corner uprights 18 of the lower crate lying underneath.

As mentioned above, the downward deformation of the rectangular bottom 12 when placing the products in the crate may be too great, causing damage to the products already stored in the lower crate below it when stacking several crates.

Unfortunately, the formation of the protrusions 88 by thermoforming Ia leads to deformations of this type when using certain plastics. For this reason, it is recommended to provide at least one non-perforated bulge which is oriented towards the interior of the crate between the projections 88 by thermoforming at least in the rectangular bottom 18 and, if appropriate and necessary, in the walls 14, 16 of the crate.

In the construction of the plastic crate of the present invention shown in FIG. 1 and 8, which is equally provided on its walls with the aforementioned bulges, said bulges have the form of a plurality of bulges 84 disposed between the protrusions 88 and directed towards the interior of the container. Like the protrusions 88, said bulges 84 may be made in a variety of shapes that are not a spherical cap shape shown in FIG. 8, not limited.

Alternatively, the curvature of the rectangular bottom 18 and, optionally, the walls 14, 16 of the crate facing the interior of the crate can be expediently disposed over the entire surface located between the protrusions 83.

As shown in FIG. 1-4, each of the four walls 14 and 16 is provided with an upper flange 86 bent outwardly from the crate 10 at an angle of at least about 90 degrees. This characteristic feature allows the walls 14 and 16 of the crate to be reinforced and reinforced readily. At the same time, it eliminates any danger of cutting people who will handle crates.

As specifically shown in FIG. 1 to 4, the top flange 86 of each of the walls 14, 16 is interrupted before the end of the crate by the fixed face of the hollow corner uprights 18 The interruption is preferably gradual, i.e. skewed or rounded so that any danger of cutting is still eliminated. that will handle the crates.

When stacking the crates 10 on pallets, this feature allows the crates to be placed in the corners of a shaft formed by four vertical angular elements 88 (see FIG. 4), which facilitates the storage and packaging of a corresponding number of crates, for example by means not shown, such as flexible plastic films.

Preferably, it is a plastics material. of which the crates 10 are made, translucent or even transparent, which facilitates the acceptance and inspection of the products in the crates stored or transported therein. This characteristic makes it relatively easy to control the type of products, their size, their current status and the like.

Alternatively, the plastic from which the crates 10 are made may be opaque. For this purpose it is advantageous to use a colored transparent plastic. This feature is advantageously used for certain special cases in the storage and transport of products requiring protection against photosynthesis, such as certain types of lettuce. This eliminates the need for the colored protective paper to be placed in the crate inevitably.

Claims (10)

A plastic crate (10), comprising a rectangular bottom (18), four walls (14, 16) and four hollow corner uprights (18), wherein at least the rectangular bottom and walls are formed of a strip of plastic having apertures Each of which is surrounded by a thermoformed protrusion, characterized in that said protrusions (22) are oriented outwardly from the crate and at least two of these protrusions (22a) are formed on the crate bottom (12), at least extending two of the four hollow corner uprights (18) so as to allow the hollow corner uprights to enter the uprights of the underlying crate. Crate according to claim 1, characterized in that the plastic strip (12), at least at the bottom of the crate, has at least one non-perforated thermoformed curvature (24) which is positioned between the protrusions (22) and oriented inwardly crates. Crate according to claim 2, characterized in that the bulge (24) is distributed over the entire surface area between the projections (22). Container according to claim 2, characterized in that the bulge comprises a plurality of bulges (24) located between the protrusions (22). Container according to any one of the preceding claims, characterized in that the walls (14, 16) are elastic. Crate according to any one of the preceding claims, characterized in that each of the four crate walls (14, 16) is provided with an upper rim (86) bent outwardly from the crate at an angle of at least about 90. Container according to claim 6, characterized in that the upper flanges (86) are interrupted by a fixed face of the hollow corner uprights (13). Crate according to any one of the preceding claims, characterized in that it is made of transparent or translucent plastic. Crate according to any one of claims 1 to 1 ', characterized in that. It is made of opaque plastic. Crate according to any one of the preceding claims, characterized in that the bottom (18), the walls (14, 16) and the hollow corner uprights (16) of the crate are formed by cutting and bending from one and the other extruded plastic sheet.