EP3083423A1

EP3083423A1 - Container comprising a bottom provided with a varying arch

Info

Publication number: EP3083423A1
Application number: EP14803180.0A
Authority: EP
Inventors: Michel Boukobza; Pierrick Protais
Original assignee: Sidel Participations SAS
Current assignee: Sidel Participations SAS
Priority date: 2013-12-17
Filing date: 2014-10-27
Publication date: 2016-10-26
Anticipated expiration: 2034-10-27
Also published as: WO2015092172A1; US20160236807A1; CN105705421A; FR3014852B1; US9701433B2; FR3014852A1; EP3083423B1; CN105705421B

Abstract

Plastics container (1) comprising a body (2) with a polygonal section which extends along a main axis (X), a shoulder (4) which extends in continuation of the body (2) on an upper side, a neck (5) which extends in continuation of the shoulder (4), and a bottom (3) which extends in continuation of the body (2) on a lower side, the bottom (3) comprising: an annular seat (9) defining a standing perimeter (10), having a polygonal contour formed from a plurality of sides and vertices, and approximately perpendicular to the main axis (X); a central peg (16) having a side wall (17) that has a generally axisymmetric frustoconical shape about the main axis (X) and which is connected to the rest of the bottom (3) by a connecting fillet (19) which has a radius that is variable in revolution about the main axis (X) of the container (1).

Description

Container comprising a bottom provided with an evolutionary arch

Containers having an annular bottom defining a perimeter of polygonal contour formed of a plurality of sides and tops, and a central pin having a generally frustoconical side wall of revolution around the main axis and which connects to the rest of the bottom by a connection fillet.

Containers having such a structure are made to meet technical or aesthetic requirements. Among the containers of this type, meeting technical requirements, there are stackable containers, the latter being shaped to be stacked on top of each other and provided for this purpose with a substantially complementary bottom and neck that the neck of an underlying container can be inserted into a hollow in the bottom of an identical upper container, the bottom thereof resting on a shoulder of the underlying container.

To allow such a stack, the bottom of each container is provided with an annular base defining a laying plane complementary to a peripheral bearing surface defined on the shoulder of an underlying container, and a pawn central to accommodate the neck of the underlying container.

The stack of the containers subjects them to significant axial compression forces which can induce deformations by buckling, which can cause a collapse of the stack. Experience shows that containers with a polygonal section (typically square or rectangular) offer better buckling resistance than circular (or oval) section containers. It therefore tends to favor the polygonal section for the manufacture of stackable containers. In the present context, the terms "polygon" and "polygonal" do not refer only to a perfect geometry (purely mathematical and theoretical) in which the sides of the polygon are straight line segments and its vertices of points, but also covers geometries approximations in which the vertices of the polygon are rounded, and in which the sides can be curved (typically in the form of arcs). In practice, it goes without saying that only the approximate geometries

S001 B119WO-PMB13049 Version: TQD are taking place, given the difficulties of properly forming a container with perfect polygonal geometry.

An illustration of a stackable square section container (according to the terminology defined above) can be found in the application FR 2 983840 or its international equivalent WO 2013/088006.

This container gives overall satisfaction but remains perfectible: flatness defects have indeed been noted repeatedly in the laying plan. These flatness defects, which can affect the stability of the container, seem to result from difficulties for the material to properly take the mold impression in certain areas of the bottom. Imperfect impression taking has been found mainly in containers with a small polygonal section (typically 0.5 I), mainly on sections of the laying plane extending on the sides of the polygon. This phenomenon undoubtedly finds its cause in the asymmetry of revolution of the container, since the symmetrical containers do not generally have flatness defects of the laying plane.

One solution to try to improve the impression of bottoms container polygon section is to use blow molds whose mold bottom or part thereof is moved towards the neck of the container (its opposite part at the bottom) during the forming steps to promote the impression of the bottom of the container. The displacement step, which allows to accompany the material of the bottom of the container during the displacement of the mold bottom, is called "boxing" and the containers thus obtained are called "boxed bottom" containers. However, it was found that while boxing brings some improvement, the fact remains that, in some cases, the flatness of the laying plan is not perfect.

One solution to this problem would be to modify the shape of the container to make it symmetrical of revolution. But, as we have seen, this solution would not satisfy the constraints specific to stacking, which give preference to a polygonal section (typically square or rectangular). In addition, even if, for certain types of containers (including some stackable containers), a symmetrical section of revolution is acceptable, the fact of being able to obtain section containers

S001 B119WO-PMB13049 Version: TQD Polygonal with good footprints undeniably opens perspectives in terms of creativity.

An object is therefore to provide a container with a polygonal section, whose bottom provides good ease of forming (also called blowability), in order to obtain a suitable laying plane, and which also offers good mechanical strength to the forces due to vertical compression, especially in the case of superposition or stacking.

For this purpose, it is proposed a plastic container, comprising a body with a polygonal section which extends along a main axis, a shoulder which extends in the extension of the body of an upper side, a neck which is extends in the extension of the shoulder, and a bottom which extends in the extension of the body of a lower side, said bottom comprising:

- An annular seat defining a polygonal contour of the perimeter formed of a plurality of sides and vertices, substantially perpendicular to the main axis;

a central pin having a generally frustoconical side wall of revolution about the main axis and which is connected to the remainder of the bottom by a connection fillet which has a variable radius in revolution about the main axis of the container, this ray having a minimum value in any sector bounded by a top of the installation perimeter, and a maximum value in any sector bounded by one side of the installation perimeter.

This container provides both good puffability and good mechanical strength to the compressive forces generated by an overlay or a stack. In particular, it has been found that the laying plan does not suffer from measurable flatness defects, in particular for containers of small capacity (in particular 0.5 I).

Various additional features may be provided, alone or in combination:

the radius of the fillet has its maximum value in any bisecting plane at one side of the installation perimeter;

the radius of the fillet has its minimum value in any bisecting plane at the top of the installation perimeter;

S001 B119WO-PMB13049 Version: TQD the radius of the fillet is continuously variable between its minimum value and its maximum value;

the maximum value and the minimum value of the radius of the fillet are in a ratio between 2 and 3;

the maximum value and the minimum value of the radius of the fillet are in a ratio of approximately 2.5;

the placement perimeter has a square outline comprising four sides and four vertices;

the radius of the fillet has four maximum values at the sides, and four minimum values at the vertices;

the radius of the connection fillet has sinusoidal variations in revolution around the main axis;

the shoulder comprises, under the neck, a frustoconical bearing surface and, at its junction with the body, a peripheral bearing surface, with a polygonal contour, complementary to the installation perimeter defined by the annular seat, substantially perpendicular to the axis main.

Other objects and advantages will become apparent in light of the description of embodiments, given below with reference to the accompanying drawings in which:

Figure 1 is a perspective view from below, showing, in a realistic manner, a polygonal section container;

Figure 2 is a realistic detail view showing, on an enlarged scale, the bottom of the container of Figure 1; for a better understanding of the forms of the bottom, some lines marking the curvature of the surfaces of this one have been traced; furthermore, in order to materialize the installation perimeter, the latter has been filled with a honeycomb pattern, and to materialize the fillet of connection of the central pin, the latter has been filled with a dotted pattern;

FIG. 3 is a bottom plan view, realistic, of the bottom of FIG. 2, on which the installation perimeter and the connection fillet of the central pin are also filled, respectively by a honeycomb pattern and by a pattern. dotted;

FIG. 4 is a flat sectional view of the bottom of FIG. 3, along the broken section line IV-IV, which also shows

S001 B119WO-PMB13049 Version: TQD the shoulder of a container on which the bottom of Figure 3 would be stacked;

Figures 5 and 6 are detail views of the bottom, on an enlarged scale, according to the rectangular inserts V and VI plotted in Figure 4;

FIG. 7 is a diagram illustrating the variations of the radius of the connection fillet from the pin to the remainder of the base, as a function of the angle between the half-plane of measurement and a half-reference plane centered on one side of the installation perimeter. , on a complete revolution around the axis of the container.

In Figure 1 is shown a container 1 formed by blowing or stretching blow from a thermoplastic preform such as PET (polyethylene terephthalate). This container 1, in this case a bottle, is typically of a capacity of 0.5 I but this capacity is not limiting and could be greater, for example 1.5 I.

The container 1 comprises a body 2 which extends along a main axis X. The body 2 is of cross section (that is to say perpendicularly the main axis X) polygonal. The terms "polygon" and "polygonal" have, in the present application, a broad meaning and are not limited to the strict mathematical definition of a closed geometry consisting of line segments (forming the sides of the polygon) joined by their extremities (forming the point vertices of the polygon), but cover approximate geometries in which the sides can be curved (for example in the form of arcs of circle), and the rounded vertices. According to this definition of the polygon, the cross section of the container illustrated in the figures (see in particular Figure 3) can be described as square.

The sides of the polygon formed by the cross-section of the body 2 do not necessarily have the same length of arc, and the angles at the vertices are not necessarily constant. In other words, the polygon is not necessarily regular. Similarly, the number of sides (equal to the number of vertices) can be indifferently even or odd. In the present case, in the illustrated square embodiment, this number is even, equal to 4.

The body 2 is extended, on a lower side, by a bottom 3, and, from an upper side opposite the bottom 3, by a shoulder 4 itself prolonged

S001 B119WO-PMB13049 Version: TQD by a neck 5 defining a drinking. The neck 5 is arranged (for example threaded) to allow the removable attachment of a plug 6.

The shoulder 4 forms a transition between the neck 5 and the body 2. The shoulder 4 comprises, under the neck 5, a frustoconical bearing surface 7. As illustrated in FIG. 4, the frustoconical bearing surface 7 is not directly contiguous with the body 2, the shoulder 4 comprising a peripheral face 8 which, in the case of a stackable container, is a contour bearing face. polygonal (in the general sense indicated above) similar to that of the section of the body 2. In this case, this contour is square.

This bearing surface 8 extends substantially in a transverse plane from an upper end of the body 2, to an inner edge forming a junction with the frustoconical surface 7. According to a preferred embodiment, illustrated in FIG. 4, the peripheral support surface 8 is not exactly flat but forms a slight clearance (at an angle of a few degrees).

As can be seen in FIG. 4, the bottom 3 may be shaped to accommodate the upper part (shoulder 4 and neck 5) of an identical underlying container 1, so as to allow the containers 1 to be stacked. More precisely , the bottom 3 is partially conformed in a manner complementary to the shoulder 4, so as to allow stacking by simple insertion of the shoulder 4 of the underlying container 1 into the bottom 3 of the upper container 1.

Thus, in such a case of stackable container, the bottom 3 comprises, in the first place, an annular base 9 which extends in the extension of the body 2 and defines a perimeter 10 of complementary installation of the peripheral support surface 8 of the shoulder 4.

The laying perimeter 10 is a strip of material of small width relative to the overall transverse extension of the bottom 3. To facilitate the interlocking on the peripheral bearing surface 8 of the underlying container 1, the perimeter 10 of pose is not exactly flat but has, relative to a transverse plane, a slight undercut, as illustrated in FIG.

As illustrated in Figures 2 and 3, applicable to stackable or non-stackable containers, the perimeter 10 has a polygonal contour similar to that of the container 1. In this case, this contour is square (in the sense indicated above). The perimeter 10 for laying comprises a plurality of straight or curved sides 11 (as in the example

S001 B119WO-PMB13049 Version: TQD illustrated), and as many summit areas (hereinafter more simply referred to as vertices) 12 where the sides meet. As can be seen in FIGS. 2 and 3, where the perimeter 10 for laying is materialized by a honeycomb pattern, the vertices 12 are rounded (it is therefore understood that they are not punctual but have a certain length arc).

More precisely, the sides 11 of the laying perimeter 10 have been materialized by a relatively loose honeycomb pattern, and the vertices 12 by a denser honeycomb pattern. The connecting lines between the sides 11 and the vertices 12 are provided for information only, and are invisible on the material container.

In the illustrated example, where the perimeter 10 of laying is regular (it is in this case a square), this perimeter 10 is invariant by rotation about the main axis X of an angle of -, where N is the number of sides (or vertices) of the polygon. Consequently, the geometric properties of each side 11 are transposable to the other sides 11, just as the geometric properties of each vertex 12 are transposable to the other vertices 12.

We are therefore interested in a single pair on the 11-vertex 12 side, and we note P1 and P2 the two secant half-planes on the main axis X and flanking the vertex 12, and P3 the half-plane s' extending from the main axis X and flanking, with the plane P2, the side 11. The planes P1 and P2 together define a first sector S1 of the space delimited by the vertex 12 (in other words, s pressing the ends of the vertex 12 at the junctions with the adjacent sides 11), and the planes P2 and P3 together define a second sector S2 of the space, adjacent to the first sector S1, and delimited by the side 11 (in d). other words, relying on the ends of the side 11 at the junctions with the adjacent vertices 12).

The annular seat 9 also defines an annular cheek 13 which extends undercut from an inner edge of the perimeter 10 of application, and is substantially complementary to the frustoconical bearing surface 7 of the underlying container 1, adjacent the junction of the frustoconical seat 7 and the face 8 support device.

S001 B119WO-PMB13049 Version: TQD The bottom 3 comprises, secondly, a central portion 14 which extends from the seat 9 - and more precisely from an inner edge 15 of the cheek 13, in the direction of the main axis X.

As seen in Figures 2 and 3, the central portion 14 is in two parts, and comprises:

a central pin 16 having a generally frustoconical side wall 17 of revolution about the main axis X (with a taper angle of between 10 ° and 20 °, and preferably about 12 °), this pin 16 being shaped and sized to completely encompass the plugged neck 5 of the underlying container 1, an arch 18 complementary, at least in part, to the frustoconical bearing surface 7 of the shoulder 4 of the underlying container 1, this arch 18 extending from of the cheek 13 towards the main axis X.

The side wall 17 of the pin 16 is described as "globally" frustoconical insofar as the wall 17 could be ribbed while having, at its apex, a narrower width than at its base.

The pin 16 is connected to the remainder of the bottom 3 by a connection fillet 19 whose radius is noted R, measured in any half plane plane P axial (that is to say any half-plane extending from the main X axis). P0 denotes an axial reference half-plane extending from the main axis X and passing through the middle of one of the sides 11 (located on the right in Figures 2 and 3). On the other hand, the angle between any plane P and the plane P0, measured in the trigonometric (or counterclockwise) direction about the main axis X, is noted.

As can be seen in FIGS. 2 and 3, as well as in FIGS. 5 and 6, the radius R of the fillet 19 is variable in revolution around the main axis X, that is to say that the radius R is a variable function of A.

In particular, the radius R presents:

a minimum value Rm in the first sector S1 delimited by the vertex 12 (or in any equivalent sector delimited by any vertex 12 of the perimeter of laying),

a maximum RM value in the second sector S2 delimited by the side 11 (or in any equivalent sector delimited by any side 11 of the perimeter 10).

By definition, the maximum RM value of radius R is strictly greater than its minimum value Rm:

S001 B119WO-PMB13049 Version: TQD RM> Rm

According to a particular embodiment illustrated in the figures, in which the container 1 exhibits plane symmetries (with respect to axial planes passing through the midpoints of the sides 11 or by the midpoints of the vertices 12), that is to say that the polygon formed by the section of the container (or by the laying perimeter) is regular, the minimum value Rm is measured in the bisecting plane of any sector S1 delimited by a vertex 12, and the maximum value RM is measured in the bisecting plane any sector S2 delimited by a side 11.

Thus, in the example illustrated in the figures, where the installation perimeter 10 (like the section of the body 2) has a square shape, the radius R of the fillet 19 passes through four minimum values Rm (at the vertices 12, c that is to say in the bisecting planes of the vertices 12), and four maximum RM values (at the right of the sides 11, that is to say in the bisecting planes of any side 11).

It follows from this variability of the radius R better bottom blowing 3, that is to say a greater ease - and better quality - of forming the bottom 3. Indeed, the relatively large value of the radius RM in the right sides 11 allows, in any sector S2, to minimize the amount of material required for forming. Given the relative narrowness of the volume defined between the pin 16 and the body 2 in the container 1 (especially when it is of low capacity - typically 0.5 I), this results in a better flow of the material towards the 9 due to the greater amount of material devoted to the formation of the leave 19 and, ultimately, a better flatness of the perimeter 10 pose.

According to a preferred embodiment, the radius R is continuously variable between its minimum value Rm and its maximum value RM. A curve has been plotted on the diagram of FIG. 7 illustrating the variations of the radius R over a complete revolution around the principal axis X, the angle A (measured in radians) thus varying between the zero value and 2π. It can be seen that, given the arbitrary definition of the null angle (in the bisecting plane of one side 11) the radius R presents its

3 5 7

minimum Rm value for anal A = -, A = -, A = -, A = -, and its value

4 4 4 4

Maximum RM at angles = 0, A = -, A = π and A = -.

S001 B119WO-PMB13049 Version: TQD Note that, in the illustrated example, the radius R has sinusoidal variations (at least in approximation) in revolution around the main axis X (that is to say as a function of the angle A).

Moreover, the maximum value RM and the minimum value Rm of the radius R are preferably in a ratio of between 2 and 3:

RM

2 <<3

rm

In the illustrated embodiment, this ratio is approximately 2.5:

RM

- = 2.5

rm

As seen in the figures, and in particular in FIGS. 2 and 3, the radial extension of the vault 18, measured in a transverse plane (perpendicular to the main axis X), varies inversely with the radius R of the leave 19. Thus, the radial extension of the vault 18 is maximum in the bisecting plane at any vertex 12 and minimum in the bisecting plane at any side 11. In some cases (as in the example illustrated), it may be that radial extension of the vault 18 is zero or close to the zero value, in the bisecting plane to any side 11. In other words, in this embodiment, the side wall 17 of the pin 16 is connected directly via the leave 19 , in the seat 9, and more precisely in the cheek 13. In this case, the arch 18 is not, strictly speaking, unitary, but formed by a set of portions angularly distributed around the main axis X and centered on the bisecting planes of the vertices 12. This design does not the stability of the container. In particular, in the illustrated square embodiment, the arch 18 located at the vertices 12 ensures sufficient support on the frustoconical bearing surface 7 of the underlying container 1.

When, as shown in Figure 4, the container 1 is stacked on an underlying container 1, the shoulder 4 of the underlying container 1 being inserted into the bottom 3 of the upper container 1: the neck 5 the underlying container (cap 6 included) is housed in the pin 16 of the upper container 1;

the perimeter 10 for laying the upper container 1 is pressed against the annular peripheral bearing surface 8 of the underlying container 1;

the outer edge of the frustoconical bearing surface 7 of the underlying container 1 comes to fit into the cheek 13 of the upper container 1;

S001 B119WO-PMB13049 Version: TQD the arch 18 of the upper container 1 is pressed against the frustoconical bearing surface 7 of the underlying container 1.

As we have seen, it results from the variability of the radius R, and in particular from the minimum value Rm at the vertices 12, that a smaller amount of material is necessary for the formation of the seat 9 in the sides of the polygon, for the benefit of better puffability of the container 1. In particular, it results in a better formation of the perimeter 10 laying, and therefore a better stability of the container 1, especially during its stack where the compression forces exerted on an underlying container may be better distributed.

S001 B119WO-PMB13049 Version: TQD

Claims

Plastic container (1), comprising a body (2) with a polygonal section extending along a principal axis (X), a shoulder (4) extending in the extension of the body (2) of an upper side, a neck (5) which extends in the extension of the shoulder (4), and a bottom (3) which extends in the extension of the body (2) of a lower side, said bottom (3) comprising:

an annular seat (9) defining a perimeter (10) for laying, with a polygonal contour formed by a plurality of sides and vertices, substantially perpendicular to the main axis (X);

a central pin (16) having a generally frustoconical side wall (17) of revolution about the main axis (X) and which is connected to the remainder of the base (3) by a connection fillet (19), this receptacle being characterized in that the connection fillet (19) has a radius (R) variable in rotation about the main axis (X) of the container (1), this radius (R) having a minimum value (Rm) in any sector ( S1) delimited by a vertex (12) of the perimeter (10) laying, and a maximum value (RM) in any sector (S2) delimited by a side (11) of the perimeter (10) of laying.

2. Container according to claim 1, characterized in that the radius (R) of the fillet (19) connection has its maximum value (RM) in any bisecting plane at one side (11) of the laying perimeter.

3. Container according to claim 1 or claim 2, characterized in that the radius (R) of the fillet (19) connection has its minimum value (Rm) in any bisecting plane at a vertex (12) of the perimeter (10) deposit.

4. Container according to one of the preceding claims, characterized in that the radius (R) of the fillet (19) connection is continuously variable between its minimum value (Rm) and its maximum value (RM).

5. Container according to one of the preceding claims, characterized in that the maximum value (RM) and the minimum value (Rm) of the radius (R) of the fillet are in a ratio between 2 and 3.

S001 B119WO-PMB13049 Version: TQD

6. Container according to one of the preceding claims, characterized in that the maximum value (RM) and the minimum value (Rm) of the radius of the fillet (R) connection are in a ratio of about 2.5.

7. Container according to one of the preceding claims, characterized in that the perimeter (10) of laying has a square contour comprising four sides (11) and four vertices (12).

8. Container according to claim 7, characterized in that the radius (R) of the fillet (19) connection has four values (RM) maximum to the right of the sides (11), and four values (Rm) minimum to the right of the vertices (12).

9. Container according to one of the preceding claims, characterized in that the radius (R) of the fillet (19) connection has sinusoidal variations in revolution about the axis (X) main.

10. Container according to one of the preceding claims, characterized in that the shoulder (4) comprises, under the neck (5), a frustoconical bearing surface (7) and, at its junction with the body (2), a face (8) support device, polygonal contour, complementary to the perimeter (10) of laying defined by the annular seat (10) substantially perpendicular to the axis (X) principal.

S001 B119WO-PMB13049 Version: TQD