WO2007083266A2

WO2007083266A2 - Disposable plastic container with bellow- shaped side wall

Info

Publication number: WO2007083266A2
Application number: PCT/IB2007/050138
Authority: WO
Inventors: Gianfilippo Pagliacci
Original assignee: Concordia Development SRL
Current assignee: Concordia Development SRL
Priority date: 2006-01-18
Filing date: 2007-01-16
Publication date: 2007-07-26
Anticipated expiration: 2008-07-18
Also published as: WO2007083266A3; AR059048A1

Abstract

Disposable container, of the type wherein at least part of the lateral surface of the container (1) consists of a bellow- shaped structure comprising a plurality of adjacent folds joined by internal (2) and external (3) hinge bands, respectively. At least the internal hinge bands (2) have, in a cross-section, a lobed structure comprising mutually alternate ridges (4) and valleys (5) which are continuously joined, the ridges and the valleys of one of said internal hinge bands (2) being offset, in the projection on a perpendicular plane to the container axis (A), with respect to the ridges and valleys of the immediately surrounding internal hinge bands. In correspondence of said ridges there are further provided shape stiffening areas (6) of the bottle wall. Each of said stiffening areas (6) is joined to the surrounding stiffening areas by slanting ribs (8).

Description

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LIGHT-WEIGHT, DISPOSABLE PLASTIC CONTAINER WITH BELLOW-SHAPED

SIDE WALL HAVING A HIGH DEGREE OF SHAPE STABILITY DURING USE

* * * * *

The present invention refers to a disposable plastic container of the type having a bellow-shaped side wall, reduced weight and a high degree of shape stability. In particular, the invention concerns a container with a bellow-shaped side wall comprising structural features guaranteeing a particularly high degree of lateral and axial stability of the container to impacts and to loads, both during transport and during use, despite employing for the manufacturing thereof a remarkably smaller amount of plastic material compared to current standards , the container volume being the same .

Containers, and in particular bottles, consisting of a circular-section or polygonal-section, cylindrical container are known in the art, whose walls consist of a bellow-shaped structure, i.e. characterised by a series of adjacent folds joined by external and internal hinge bands, respectively, being round-shaped and lying on perpendicular planes to the bottle axis. Bottles having side walls thus shaped have mainly been suggested for manufacturing variable-volume containers. Such containers hence have an extended configuration of the bellow- shaped structure when the bottle is full, whereas - as the contents are being used - the inner volume of the container may vary, through progressive folding of the bellow structure, so as to adapt the volume of the container to the reduced liquid contents and keep the air volume present at the top of the container to a minimum.

Based on this state of the art, the Applicant has carried out intense research and experiments on the possible manufacturing of plastic containers of the above-described type - and in particular of containers obtained through preform blow moulding of suitable thermoplastic polymers, such as polyethylene-terephthalate, polyethylene, polyvinilchloride, polycarbonates and the like - using for the moulding of the container much lighter preforms than those currently used for same-volume containers, whose weight for example lies between 50 and 70% of the standard one, to check for possibly large savings of material and hence of costs in the manufacturing of said containers . The weight of the containers on the market, i.e. the amount of plastic material used for the manufacture thereof, has of course already been the object of a constant optimisation process, so that the standard weights currently used for different-volume containers on the market are considered by experts in the field as the lowest possible ones for obtaining containers having mechanical features suitable to allow safe handling and transport thereof, without permanent deformations, following impacts or accidental loads.

As a matter of fact, in his experiments on containers with bellow-shaped side walls, the Applicant was able to realise that, by reducing the amount of material of which the containers are made up compared to said standard values, i.e. by reducing the weight of the respective preforms to below the values currently in use, and by consequently moulding containers with thinner walls, the container itself, despite maintaining its shape sufficiently unchanged in a horizontal direction precisely due to the presence of the bellow-shaped side structure which causes a stiffening in such direction, the container instead easily undergoes stability problems in a vertical direction showing various drawbacks, substantially due to an undesired, spontaneous folding over of the individual container folds during use (collapse) , both symmetrically and asymmetrically, the latter phenomenon also comprising the lateral misalignment of the container (deflection) .

These drawbacks would arise the more conspicuously, the larger the container size, for example in particular in the large jugs used for automatic water dispensers (so-called "water-coolers"), having volumes comprised between 5 and 15 1, nowadays largely available in many countries replacing conventional 1-3 -litre bottles. In the case of these large- volume containers, spontaneous collapse or deflection phenomena would further have particularly negative consequences both during transport - where the stability of the palletload of piled containers would be affected - and during use.

As a matter of fact, in this particular use, the bellow- shaped structure of the side walls of the container must necessarily be at least sufficiently rigid so as not to collapse under the weight of the water therein contained; in the contrary, the container would empty spontaneously as soon as it is turned upside down, progressively collapsing and flooding the same water-cooler or affecting the stability of the jug on the water-cooler in case of deflection.

In this respect it must also be considered that during transport from the factory to the end user, the container is handled without special care and is hence subject to accidental loads and impacts which may cause localised deformations and yielding on the container surface, all damages which represent possible areas susceptible of localised collapse. Moreover, even during the final installation of the container on the distributor by the user, and in particular during the operation of turning the container upside down, the portion of the bellow- shaped lateral surface facing downwards undergoes, precisely due to the relatively high weight of the jug water contents, partial yielding which may also cause a preferential collapse of that side of the container and hence favour the above-described misalignment problems . The object of the present invention is hence that of providing a container of the above-described type having, the volume being the same, a remarkably lower weight than that of known-type containers currently on the market and nevertheless completely free from the above-described drawbacks i.e. from problems of excessive yielding which may cause a spontaneous collapse of the container and a consequent, undesired emptying in an upturned position of the same, as well as from asymmetrical collapse problems and consequent deflection of the container during use and transport thereof. According to the present invention such object is achieved through a disposable container having the features described in the accompanying claim 1. Additional features of the container according to the present invention are defined in the dependent claims . Further features and advantages of the container of the present invention will in any case be more evident from the following description of some preferred embodiments of the same, shown in the accompanying drawings, wherein: fig. 1 is a front view of a first embodiment of a bottle according to the present invention; fig. 2 is a section view according to line II - II of an internal hinge band of the bottle of fig. 1; fig. 3 is a section view according to line III - III of an internal hinge band of the bottle of fig. 1 adjacent to the one shown in fig. 2; fig. 4 is a section view similar to fig. 2 of a different embodiment of the internal hinge band; fig. 5 is a front view of a second embodiment of the bottle of the present invention; and fig. 6 is a front view of a third embodiment of the bottle of the present invention.

In bottle 1 according to the present invention, the side wall has a basic structure characterised by a very small thickness and a bellow-shaped structure wherein the internal hinge bands 2, i.e. the joining bands between two adjacent bellows facing inwards of the bottle, rather than having the same, generally circular or polygonal cross-section structure which characterises the bottle, have a characteristic lobed structure comprising ridges 4 and valleys 5, having a longer and a shorter distance, respectively, from axis A of container 1. Moreover, adjacent internal hinge bands 2 are oriented in a mutually offset manner, as shown in figs. 2 and 3, so that, in a projection on a horizontal plane, the ridges of a band 2 are comprised between two valleys of adjacent bands 2 and viceversa.- The external hinge bands 3, i.e. the joining bands between two adjacent bellows facing outwards of the bottle, preferably have the same circular or polygonal cross-section structure of bottle 1, so that the outer surface of the bottle, precisely limited by said bands 3, maintains the conventional cylindrical or polygonal shape. However, also external hinge bands 3 may have a lobed structure similar to that of bands 2, if it is desirable to achieve a higher degree of stiffening of the bellow-shaped structure of bottle 1. When also bands 3 have a lobed structure, such structure must be suitably oriented in respect of the lobed structure of adjacent, internal hinge bands 2, so as to achieve a well-balanced, final bottle structure.

Due to this very special arrangement, when collapse begins in a lateral area of the bottle, for example in the lateral area which has experienced yielding while turning the bottle upside down, the ridges of the internal bands immediately adjacent to the collapsing area become stressed and hence offer a remarkably higher resistance to further collapse in that area than the one offered by the opposite, non-collapsed, lateral area of the container, bringing the bottle back into its original shape. In other words, whenever a partial collapse - due to impacts, localised loads or other sources of yielding - tends to cause the bottle to take up an asymmetrical structure, such same structure causes a greater resistance to collapse in that area, hence generating an automatic control of the maintenance of the original shape of the bottle. At. the same time, the offset-ridge structure of the internal hinge bands allows to impart optimal shape elasticity to the bottle, both in a horizontal and in a vertical direction, so as to improve elastic absorption of accidental loads.

It is worth pointing out that this result is completely opposite to that, illustrated above, of known-art containers which have a cross-section structure of the internal hinge bands 2 which is identical to the general structure of the container. As a matter of fact, in these known containers, the first collapse causes a further weakening of the collapsed area and of the adjacent bellows, which weakening encourages the occurrence of subsequent collapse on the same side of the bottle where the first occurred, causing the deflection phenomenon described earlier.

Thanks to this stabilised structure of the container, it is possible to achieve very remarkable weight reductions of the container, up to 50% of the current weight, the bottle volume being the same, without this causing any drawback either during transport, or during use or handling of the container. As a matter of fact, through the above-described structure of the side wall of the bottle, the structure of the same is stiffened both in a horizontal direction, avoiding any possible bottle ovalisation, and in a vertical direction, avoiding preferential progressive collapse of an asymmetrical type on one side of the container and the consequent rapid misalignment of the container

(deflection) . The stiffening thus obtained of the bellow-shaped structure is furthermore perfectly sufficient to prevent also the phenomenon of the self-emptying of the container in an upside-down position, during use on water-coolers.

The shape and number of ridges 4 and of valleys 5 of the internal hinge bands 2, as well as the difference of the distance thereof from axis A of the container can be varied in wide ranges, consequently changing curvature radiuses and inclination of the joining areas, according to the mechanical properties of the plastic material used, of the amount of such material used for manufacturing the bottle and consequently of the final thickness of the walls, and finally of the container volume. Fig. 4 shows for example a 6-lobe structure of the internal hinge band, more suited to smaller-sized containers than the 8-lobed one illustrated in figs. 2 and 3; preferably the overall lobe number of each hinge band ranges between 4 and 12. In any case the lobed structure of the hinge bands is symmetrical to the axis A of the container and ridges 4 and valleys 5 of the same are arranged at the same distance along the hinge band.

In subsequent experiments carried out by the Applicant, it has then been found out that a further improvement of the features of the container of the present invention, even more useful the larger the container volume, can be achieved by further increasing the axial rigidity (i.e. rigidity in a vertical direction) of the bellow-shaped, lateral wall of the container, despite maintaining the stabilising effect on the horizontal plane of the same bellow-shaped structure and a sufficient degree of axial elastic compressibility of the container which remarkably increases performance thereof in terms of impact resistance.

In the second embodiment of the present invention, the above-described structure of bottle 1 is hence integrated with a plurality of vertical stiffening areas 6, which further limit any possible localised yielding of the bellows making up the bottle side walls. Preferably such areas 6 are arranged precisely in correspondence of ridges 4 of internal bands 2, as can be seen in fig. 5. The higher degree of stiffening of areas 6 is preferably obtained through a shape change of the container in that area, and is hence defined as "shape stiffening" in the following.

In other words, in correspondence of areas 6 the walls of container 1 do not show substantial structure changes or thickness changes over the surrounding areas of the container, but rather a remarkable change of shape over the above-described lobed, circular shape of internal bands 2. Such shape change can simply be due to the fact that said ridges 4, rather than joining softly with the adjacent valleys 5 of the internal hinge band 2, have a more or less pronounced edge area. Preferably the shape change in correspondence of stiffening areas 6, however, comprises forming one or more vertically-arranged walls, capable of countering the compliance of the bottle in an axial direction. In the embodiment shown in fig. 4, for example, in correspondence of ridges 4 of internal bands 2, the diameter of said bands abruptly increases, by a short distance, nearly- matching the diameter of external hinge bands 3. Stiffening areas 6 are hence shaped, on the external surface of bottle 1, as small columns joining two adjacent, external hinge bands 3, in correspondence of ridges 4 of internal hinge band 2 located between the same. Bach pair of stiffening areas 6 arranged on a same horizontal plane hence limits a cavity 7 arranged between the same and having a varying depth, which is lowest near stiffening areas 6 and is highest in a central position between the same, i.e. precisely in correspondence of the stiffening areas 6 of the internal hinge bands 2 lying immediately above and below. In this position cavity 7 hence has its maximum compliance, allowing a partial coming together of the above-said stiffening areas 6 following an axial load on the bottle and thereby imparting to the same the desired elastic compressibility in a vertical direction.

In the second embodiment described above, the external opening of cavities 7 has a generally rectangular shape with rounded off edges, clearly shown in fig. 5, limited above and below by external hinge bands 3 and laterally by column-shaped, stiffening areas 6.

A third embodiment of the bottle according to the present invention has been devised by the Applicant to further increase the degree of elastic, axial compressibility of the bottle, i.e. the capability to withstand high axial loads - such as for example in the case of a full bottle falling from a certain height - without this causing permanent deformations nor, even less so, bottle breakage.

According to this third embodiment of the bottle, diagrammatically illustrated in fig. 6, each stiffening area 6 is joined through slanting ribs 8 to the immediately surrounding areas 6 arranged on the adjacent, external hinge bands 2, so that cavities 7 thus have a larger and generally rhombus- shaped/oval-shaped opening, whose lateral inclined surfaces 9 extend across that bottle portion which, in the preceding embodiments, made up external hinge bands 3.

The lateral surface of the bottle according to this third embodiment hence has a reticular structure with rhombus- shaped/oval-shaped mesh, whose strong points consist of the stiffening areas 6 which represent the nodes thereof. Such structure is capable of providing a high degree of elastic deformability, i.e. it is fully free from permanent deformations, which allows to impart the bottle a really excellent degree of shape stability even in the presence of very large localised loads, as occurs for example following bottle impacts or the bottle falls off loading means during transport operations .

As is clear from the preceding description, the various embodiments of the bottle according to the present invention are all suitable for achieving the set object, i.e. that of providing a much lighter container with respect to conventional, same-volume containers, without this implying any worsening of the mechanical properties of the bottle and, on the other hand, achieving remarkable improvements in terms of the absence of permanent deformations in the bottle following impacts or other localised accidental loads.

The present invention has been described in a diagrammatical and concise way, with reference to some preferred embodiments, but it is obvious that the scope of protection of the invention is not limited to such embodiments, but also comprises all the possible variants within the reach of a person skilled in the field, provided they fall within the definitions set out in the accompanying claims.

Claims

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1) Cylindrical-section or polygonal-section, disposable container, of the type wherein at least part of the side surface of the container (1) consists of a bellow-shaped structure comprising a plurality of adjacent folds joined by internal (2) and external (3) , respectively, hinge bands, characterised in that at least the internal (2) hinge bands have, in a cross- section, a lobed structure comprising alternate ridges (4) and valleys (5) , mutually connected in a continuous manner, and in that the ridges (4) and the valleys (5) of one of said internal hinge bands (2) are offset, in the projection on a perpendicular plane, to the axis (A) of the container, with respect to the ridges and valleys of the immediately adjacent internal hinge bands . 2) Container as claimed in claim 1), wherein said lobed structure is symmetrical with respect to the container axis (A) . 3) Container as claimed in claim 2) , wherein the ridges (4) and the valleys (5) of said lobed structure are distributed at the same distance along the internal hinge band (2) . 4) Container as claimed in claim 2) , wherein said lobed structure comprises a number of lobes lying between 4 and 12.

5) Container as claimed in claim 2) , further comprising shape stiffening areas (6) of the container wall.

6) Container as claimed in claim 5) , wherein said shape stiffening areas (6) of the wall of the container (1) are formed in correspondence of said ridges (4) of the internal hinge bands (2) .

7) Container as claimed in claim 6) , wherein said stiffening areas (6) consist of edge areas of the undulated profile of the internal hinge band (2) .

8) Container as claimed in claim 6) , wherein said stiffening areas (6) comprise vertical walls.

9) Container as claimed in claim 8) , wherein said stiffening areas (6) consist of short circumference portions wherein the diameter of the internal hinge band (2) suddenly increases .

10) Container as claimed in claim 9) , wherein said increased diameter is next or equal to the diameter of said external hinge bands (3) .

11) Container as claimed in any one of the preceding claims, wherein each of said stiffening areas (6) of an internal hinge band (2) is joined through slanting ribs (8) to the immediately surrounding stiffening areas (6) arranged on the adjacent internal hinge bands (2).

12) Container as claimed in claim 11) , wherein each group of four surrounding stiffening areas (6) defines a cavity (7) having a generally rhombus-shaped/oval-shaped opening, inclined walls (9) and a varying depth limited by an internal hinge band (2) .

13) Container as claimed in any one of the preceding claims, characterised in that it is a bottle for liquids. 14) Container as claimed in claim 13), wherein said bottle has a volume ranging between 1 and 20 litres.