EP2036820B1 - Plastic bottle - Google Patents

Abstract

The container has a wall section (2) attached at a mouth in a longitudinal direction of the container. A base section (4) e.g. stand surface, has an injection point (8) that lies inside in a radial direction. A central area (6) surrounds the injection point and a passage section (10) extending from the central area to the wall section. The passage section has a curvature with finite radius of curvature in one direction.

Description

The present invention relates to a container made of plastic for receiving drinks. Such containers are known from the prior art for some time and increasingly solve glass bottles as beverage containers. The advantage of these plastic containers themselves is in particular the lower weight, the optimal handling in terms of design and partly in the multiple usability. From the prior art, various bottles of various sizes for both small quantities in the range of 200ml to large quantities of 5 1 are known. These containers have a variety of forms. In the context of manufacturing processes, the preforms are inflated or expanded, for example, by means of air pressure to the plastic containers. For this purpose, the preforms are usually entered into a mold and expanded against this mold. To save costs, it is attempted to produce the plastic containers with less and less material. On the other hand, however, this means that increasingly greater demands must be placed on the stability of the bottles in relation to the amount of material used.

WO 98/28193 A1 shows in its first embodiment, a plastic container or a container according to the preamble of claim 1.

US Pat. No. 3,935,955 discloses a container bottom structure for plastic bottles used for carbonated beverages are suitable. The outer surface of the floor structure is formed with a central concave arch portion and a number of axially outwardly extending radial leg portions.

FR 2 856 380 A1 refers to a container which does not show an injection point, central region and transition region in combination.

The present invention is therefore based on the object to provide a container which has a high dimensional stability. In addition, a container is to be created, which is simpler and cheaper to manufacture in the context of the expansion process. This is inventively achieved by in container according to claim 1. advantageous Embodiments and developments are the subject of the dependent claims.

A container according to the invention made of plastic for receiving drinks has an orifice, a wall section adjoining the mouth in the longitudinal direction of the container, and a base section designed as a standing surface, wherein the wall section merges into the bottom section and the container is formed in one piece.

According to the invention, the bottom section has an injection point located in a radial direction with respect to the longitudinal direction and a central region surrounding this injection point, and a transition section extending from this central region to the wall section, this transition section being in at least one, preferably in several, and particularly preferably in each radial Direction of the container in each geometric section has a curvature with a finite radius of curvature. The radial directions are understood with reference to a longitudinal direction of the container.

In other words, the bottom portion has no rectilinear portions in the radial direction except for the central area. Although different curvatures, ie curves in different directions can merge into each other and thus there may be geometric turning points at which mathematically there is no curvature. However, there are no extended rectilinear sections provided. The advantage of such an embodiment consists in a higher stability and easier formability. By avoiding straight sections, even edges or mathematically speaking non-differentiable areas are avoided and thus the dimensional stability of the particularly sensitive bottom section is increased. Preferably, the mouth has an external thread.

In other words, the outer surface or the inner surface of the transition section can be projected in a projection in at least one direction, preferably in several, and most preferably in any direction perpendicular to the longitudinal direction, as a curve, with the second mathematical derivative of a mathematical function representing these curves not present in any section the curve outside the central region has the value 0. In other words, this curve is always curved, although it is conceivable that this curve has individual inflection points in which, for example, a positive curvature changes into a negative curvature. Consequently, a mathematical function describing this curve would possibly have isolated zeros in its second derivative. Points are therefore not considered as a section, sections are rather distances in the mathematical sense.

In an advantageous embodiment, the bottom section is designed point-symmetrical with respect to the injection point. Furthermore, the central area with respect to the geometric center of the bottom portion has a radius which is less than 15 mm, preferably less than 10 mm and more preferably less than 5 mm. In this central area a straight course of the bottom section is possible. In a further advantageous embodiment, the extended Cross-section of the container starting from the mouth towards the wall section.

In at least one radial direction outside the central region, the curve has exactly two points in which the second mathematical derivative of a mathematical function representing this curve has the value 0. Thus, considered in the radial direction of the container exactly two turning points are provided. More specifically, the bottom portion has a family of turning points, which in this embodiment are at a constant distance from the geometric center of the bottle. In this case, all inflection points are arranged substantially on a circular line around the geometric center. Essentially, it is understood that the points of inflection with respect to the radius of the container are shifted by not more than 10%, preferably by not more than 5%, with respect to the said circular line.

This is advantageous in this embodiment, the two said turning points with respect to the longitudinal axis of the container symmetrically opposite.

The curve preferably does not have the value 0 in any other radial direction outside the central region at any point.

In a further advantageous embodiment, the transition section adjoins directly to the central region. Thus, it is possible that a partial rectilinear central region is provided, which is adjoined directly by the curved transition region of the container.

In a further advantageous embodiment, the transition section has a first curvature region with a substantially constant first curvature radius. This means that the first curvature region is circular-segment-shaped curved. In a further advantageous embodiment, a second curvature region adjoins the first curvature region within the transition section, wherein this second curvature region likewise has a constant second curvature radius.

Particularly advantageously, this second curvature region adjoins directly to the first curvature region.

However, it would also be possible to design the second curvature region not in the form of a circular line but in the form of a so-called polyspline, d. H. a curve that is generated by an nth degree polynomial. In principle, it would also be possible to generate the first curvature region through a polyspline, but preferably the first curvature region is circular. In a further advantageous embodiment, the first curvature region and the second curvature region are curved in the same curvature direction. Particularly advantageously, the radius of curvature of the second curvature region is greater than the curvature radius of the first curvature region. As a result, a more curved region, viewed from the inside to the outside, merges into a less curved region.

Particularly advantageously, the bottom section is a free-formed bottom section. This means that the shaped body which generates this bottom section is not produced by cutting with a rotary body, but that, for example CAD sketches free mold surfaces were determined, which in turn form the basis for a form in which the container is expanded. Further advantages and embodiments will become apparent from the accompanying drawings.

Fig. 1

eine Projektion eines Bodenabschnitts eines Behältnisses nach dem Stand der Technik;

Fig. 2a

eine perspektivische Ansicht eines erfindungsgemäßen Bodenabschnitts;

Fig. 2b

eine Seitenansicht des Bodenabschnitts eines erfindungsgemäßen Behältnisses;

Fig. 2c

eine Bodenabschnitt und einen Teil eines Wandabschnitts eines erfindungsgemäßen Behältnisses;

Fig. 3

eine Liniendarstellung eines erfindungsgemäßen Bodenabschnitts zur Veranschaulichung der Krümmungsverhältnisse; und

Fig. 4

eine Projektion zweier Krümmungslinien für ein erfindungsgemäßes Behältnis.

Show:

Fig. 1

a projection of a bottom portion of a container according to the prior art;

Fig. 2a

a perspective view of a bottom portion according to the invention;

Fig. 2b

a side view of the bottom portion of a container according to the invention;

Fig. 2c

a bottom portion and a part of a wall portion of a container according to the invention;

Fig. 3

a line representation of a bottom portion of the invention to illustrate the curvature ratios; and

Fig. 4

a projection of two curvature lines for a container according to the invention.

Fig. 1 shows a partial representation of a (projection) curve K1 of a bottom portion 24 of a (not shown in its entirety) container according to the prior art. In each case, the lines S projecting radially out of the curve K1 give a measure of the curvature of this curve at. It can be seen that the curve K1 has a region 25 in which there is no curvature, ie in which the curve runs in a straight line. This rectilinear section can lead to increased stresses in the corresponding area and also to fractures. The reference symbol B here refers to a point of inflection in which the curvature of the curve K1 changes. The reference numeral 22 denotes a first curvature region and the reference character 26 a second curvature region.

Fig. 2a shows a perspective view of a bottom portion according to the invention. The bottom section 4 has an injection point 8 in its center and a central region 6 surrounding this injection point 8. In this case, both the injection point 8 and the central region 6 are formed substantially circular. Within this central region 6, both curved and rectilinear courses of the bottom section are possible. The central region 6 is adjoined by a transition section designated in its entirety by 10, which finally merges into the wall section 2 (not shown in its entirety). The bottom section 4 has hill-like curved areas 3, which ultimately also form the footprints for the container. Between these hills formed areas 3 are each troughs or sinks 5. The number of these depressions 5 and the hill-like curved portions may vary.

Fig. 2b shows a sectional view of the in Fig. 2a In this sectional view can be seen both an outer contour of the bottom portion 4 in a hill-like curved region 3 and the respective outer contour in the respective wells 5. In both However, areas of the respective transition section 10a, 10b is curved, that has no straight section. Even in the areas that lie between the sink 5 and the hill-like curved area 3, preferably no bends occur. Thus, it is possible, regardless of the choice of the radial directions R, which extend in the circumferential direction about the longitudinal direction L to project a curve K, which have no straight section outside the central region 6. The reference numeral 10 designates the transition section in its entirety, the reference numerals 3, 5 the considered in a particular direction transition section. The reference numeral 7 refers to a protrusion forming a subsection of the hill-like curved portion 3 and further serving as a standing surface.

Fig. 2c shows a side view of a bottom section 4 according to the invention with a subsequent wall section 2. Again, by lines both the central region of the subsidence 5 and the central region of the hill-like curved portion 3 are marked. The bottom section preferably also has no rectilinear section in a circumferential direction running along the longitudinal axis L along at least one contour line h1. Preferably, along such a lengthwise extension L1 of the bottom section 4, there is no such straight line section at any contour line hx.

Fig. 3 shows a perspective dash representation to illustrate the curvature ratios. The lines S here again indicate a measure of the curvature of the respective section to be considered. You realize that here selected curvature curve K3 also has no rectilinear sections but only turning points B, in which the curvature changes.

Preferred is as in Fig. 3 can be seen in such projections of the bottom portion, which do not run through the injection point 8 or through the central region 6, in the entire region of the bottom portion 4 is not a straight course. Also by this procedure, a particularly favorable stability of the container is achieved. Reference character K3 denotes such a curve. This curve K3 has two inflection points B, in which the direction of curvature changes.

Fig. 4 1 shows a projection of a geometric curve K1 in the area of a hill-like curved area 3 and a geometric curve K2 in the area of a depression 5. To the left of the drawn point A, the central area 6, which can also run in a straight line, follows (not shown). Between the point A and the point B, the curvature curve K1 has a downward curvature, which is also referred to below as the negative curvature.

In the point B, the negative curvature changes into a positive curvature so that the point B represents a turning point in the mathematical sense. In the subsection 12 between the point A and the point B, the curvature always changes. Thus, starting from the point A, it first increases in magnitude until it reaches a maximum value and then decreases again to the point B.

This curvature can be described by an nth degree polynomial. Between the point B and the point C is followed by another sub-section 13, in which the curvature is positive and increases up to a maximum value in the point C. Between the point C and the point D is followed by a subsection 14 in which the curvature is constant or has a constant curvature radius R1. In other words, the curve K1 here lies on a circle of a circle Kr1. In the point D, the radius of curvature increases abruptly, so that between the point D and the point E is a subsection with constant radius of curvature R2.

The curve K2 describes the curvature profile in the region of a depression 5. Preferably, the curvature is described here by a constant radius of curvature R3. The curves K2 and K1 merge into one another at the point E, and at this point E the wall section 2, which is substantially circular in shape, follows. Preferred is as in Fig. 4 the radius of curvature R1 is smaller than the radius of curvature R2 and the radius of curvature R3 is greater than the radius of curvature R1, but smaller than the radius of curvature R2.

Also in the point A, the two curves K1 and K2 merge. It should be noted that the other curves lying in the circumferential direction of the bottom section between the curve K2 and the curve K1 also merge into one another at the points corresponding to points A and E in the circumferential direction of the bottom section 4.

Claims (12)

1. Container made from plastic for holding beverages, comprising a mouth, a wall section (2) which adjoins the mouth in a longitudinal direction (L) of the container, and a base section (4) which is designed as a standing face, wherein the wall section (2) merges into the base section (4) and the container is formed in one piece, characterised in that the base section (4) has an injection point (8) located in the interior in a radial direction (R) with respect to the longitudinal direction (L), and a central region (6) which surrounds this injection point (8), and also a transition section (10) which extends from this central region (6) to the wall section (2), wherein this transition section (10) has a curvature with a finite radius of curvature in at least one and preferably in every radial direction (R) of the container in every geometric sub-section and the outer face of the transition section (10) is projected as a first curve (K1) in at least one and preferably in every direction perpendicular to the longitudinal direction (L), wherein the first curve (K1) has exactly two points (B), in which the second mathematical derivative of a mathematical function representing this curve (K1) has the value 0 characterised in that a region (12) of the first curve (K1) which is between one of these points (B) and the central region (6), comprises a continuously changing curvature.
2. Container according to claim 1, characterised in that the outer face of the transition section (10) is designed as a second curve (K2) in a projection in at least one and preferably in every direction perpendicular to the longitudinal direction (L), wherein the second mathematical derivative of a mathematical function representing this curve (K2) has the value 0 in no part of the second curve (K2).
3. Container according to claim 1, characterised in that the base section (4) is designed with point symmetry with respect to the injection point (8).
4. Container according to at least one of the preceding claims, characterised in that the central region (6), with respect to the geometric centre point of the base section (4), has a radius of less than 15 mm, preferably less than 10 mm and particularly preferably less than 5 mm.
5. Container according to claim 1, characterised in that the two points (B) lie symmetrically opposite one another with respect to a longitudinal direction (L) of the container.
6. Container according to at least one of the preceding claims, characterised in that the transition section (10) directly adjoins the central region (6).
7. Container according to at least one of the preceding claims, characterised in that the transition section (10) has a first curved region (14) with a substantially constant first radius of curvature (R1).
8. Container according to claim 7, characterised in that the first curved region (14) is adjoined on the radially outer side by a second curved region (16), wherein this second curved region (16) likewise has a constant second radius of curvature (R2).
9. Container according to claim 8, characterised in that the first curved region (14) and the second curved region (16) are curved in the same direction.
10. Container according to claim 6 or 7, characterised in that the radius of curvature (R2) of the second curved region (16) is greater than the radius of curvature (R1) of the first curved region (14).
11. Container according to at least one of the preceding claims, characterised in that the base section (4) is a free-formed base section (4).
12. Container according to at least one of the preceding claims, characterised in that the container has a liquid capacity of at least 250 ml.

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