EP3523208B1 - Petaloid base with broken valley - Google Patents

Description

The invention relates to the field of containers, in particular bottles or pots, manufactured by blow molding or stretch blow molding from blanks (preforms or intermediate containers) made of plastic material such as polyethylene terephthalate (PET).

A container generally comprises an open neck, through which the contents (usually a liquid) are introduced, a body, which gives the container its volume, and a bottom, which closes the body opposite the neck and forms a base intended to hold and maintain the container when it rests on a surface.

Containers intended for carbonated beverages, in which the pressure of the gas dissolved in the liquid induces significant mechanical stresses, are mostly provided with very high petaloid-shaped bottoms, known as “petaloid bottoms”. Such bottoms comprise projecting feet, in the form of petals, separated by convex wall portions, called hollows or valleys, which extend radially from a central zone of the bottom. The feet, of great height (that is to say in a ratio of approximately 1/2 with the diameter of the container), are intended to ensure the maintenance of the container placed on a surface; the valleys are intended to absorb the forces (thermal, mechanical) exerted by the content. An illustrative example of this type of background can be found in the international application WO 2012/069759 (Sidel Participations ).

The petaloid bottoms appear as a relatively successful solution allowing good resistance to the strong internal pressures of the containers (in particular thanks to the hemispherical shape of the valleys) which are provided with them.

However, a petaloid bottom requires a large quantity of material (a 0.5 liter container with a classic petaloid bottom, having a weight greater than or equal to approximately 18 g), as well as a relatively high blowing pressure (of order of 22 to 30 bars), to ensure correct impression taking of the feet and valleys in the manufacturing mould.

These constraints tend to disqualify petaloid bottoms for "still liquid" type applications (typically table water or non-carbonated drinks), for which the pressure is minimized blowing than the quantity of material used (today around 10 g at the most for a 0.5 l container).

It is becoming common, for certain applications of still liquids sensitive to oxidation (in particular fruit juice(s)), but also certain still waters, to replace the air above such still liquids with an inert gas (typically 'nitrogen). In practice, this operation is carried out by pouring a drop of liquefied inert gas onto the surface of flat liquids, immediately preceding the sealing of the container. This operation induces an overpressure in the containers to which this treatment is applied. Even seemingly slight (of the order of 0.5 to 1.3 bar), this overpressure is sufficient to significantly increase the stresses exerted on the bottoms, without these stresses justifying the use of petaloid bottoms. conventional (i.e. high-rise).

However, a bottom provided with a simple concave vault, if it meets a priori the requirements of economy of material and allows an easy manufacture of the containers by blow molding (we speak of containers having an easy "blowing capacity"), is not however not able to withstand without significant deformation the stresses due to the hydrostatic pressure doubled by the pressure of the added inert gas.

There is therefore a need for a container whose bottom offers increased resistance to internal stresses compared to ordinary vaulted bottoms, while not requiring as much material, nor as high blowing pressure, as an ordinary petaloid bottom.

It has therefore been proposed, cf. the international application WO2014207331 (Sidel Participations) , a petaloid bottom of low height, of which the ratio h/d between the height (h) of the feet and the overall diameter (d) of the bottom is less than or equal to 1/5, this bottom further being provided with a central dome and grooves straddling the valleys and the dome.

This bottom has interesting mechanical performance, which makes it suitable for the addition of an inert gas under pressure, provided however that the quantity of material used for the manufacture of the container is sufficient.

Also known in the state of the art is the document US 2014/183156 .

However, operators are increasingly demanding in terms of material savings, and the need is reborn to offer a new container whose bottom can, with an even reduced quantity of material, offer under pressure a sufficient mechanical resistance while having easy blowability.

• une paroi de fond de forme générale convexe vers l'extérieur du récipient,
• un dôme central formé en creux vers l'intérieur du récipient et qui s'étend depuis un sommet central jusqu'à un bord périphérique par lequel le dôme se raccorde à la paroi de fond, et
• au moins quatre pieds qui forment des excroissances à partir de la paroi de fond vers l'extérieur du récipient, séparés deux à deux par des portions de la paroi de fond formant au moins quatre vallées en creux qui s'étendent radialement depuis un dôme central du fond jusqu'à une périphérie de celui-ci,

• chaque pied ayant deux flancs, bordant chacun une vallée, et une face médiane qui, dans un plan radial, présente un profil courbe à concavité tournée vers l'extérieur du récipient et se prolonge par une face d'extrémité, les faces d'extrémités formant conjointement un anneau de pose, de section plane, interrompu au droit de chaque vallée,
• récipient dans lequel :
  • chaque vallée présente une portion interne qui s'étend à partir du dôme central et une portion externe qui rejoint la périphérie dans le prolongement de la portion interne, la portion interne et la portion externe étant, en section dans un plan radial médian à la vallée, droites et formant ensemble un angle obtus saillant vers l'extérieur du récipient et se rejoignant en un sommet situé à l'aplomb ou à proximité immédiate de l'aplomb de l'anneau de pose ;
  • le fond comprend deux groupes de vallées disposées en alternance :
    • ∘ des vallées primaires dont la portion interne se raccorde au dôme à hauteur du bord périphérique de celui-ci ;
    • ∘ des vallées secondaires dont la portion interne se raccorde au dôme entre le bord périphérique et le sommet central du dôme, à distance du bord périphérique.

To this end, a plastic container is proposed comprising a body, which extends along a main axis, and a petaloid bottom, which extends the body, this bottom comprising:

• a bottom wall of generally convex shape towards the outside of the container,
• a central dome formed hollow towards the interior of the container and which extends from a central top to a peripheral edge by which the dome is joined to the bottom wall, and
• at least four feet which form projections from the bottom wall towards the outside of the container, separated two by two by portions of the bottom wall forming at least four hollow valleys which extend radially from a central dome from the bottom to a periphery thereof,

• each foot having two flanks, each bordering a valley, and a median face which, in a radial plane, has a curved profile with a concavity facing the outside of the container and is extended by an end face, the end faces jointly forming a laying ring, of flat section, interrupted in line with each valley,
• container in which:
  • each valley has an internal portion which extends from the central dome and an external portion which joins the periphery in the extension of the internal portion, the internal portion and the external portion being, in section in a radial plane median to the valley , straight and together forming an obtuse angle projecting towards the outside of the container and meeting at a vertex located plumb or in the immediate vicinity of the plumb of the laying ring;
  • the bottom includes two groups of valleys arranged alternately:
    • ∘ primary valleys whose internal portion is connected to the dome at the height of the peripheral edge of the latter;
    • ∘ secondary valleys whose internal portion is connected to the dome between the peripheral edge and the central summit of the dome, at a distance from the peripheral edge.

This architecture provides the bottom with good mechanical rigidity, including when the container is pressurized, while having good blowability.

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

The dome has a height, measured axially between its peripheral edge and its top and, in the secondary valleys, the internal portion is advantageously connected to the dome at a distance from the peripheral edge of between 20% and 70% of said height of the dome;

In the secondary valleys, the internal portion is preferably inclined, with respect to any plane parallel to the plane of the laying ring, towards the interior of the container, by an angle advantageously comprised between 5° and 30°;

In the primary valleys, the internal portion is preferably inclined, with respect to any plane parallel to the plane of the laying ring, towards the outside of the container, by an angle advantageously comprised between 2° and 10°;

As a variant, in the primary valleys, the internal portion is inclined, with respect to any plane parallel to the plane of the laying ring, towards the inside of the container by an angle less than or equal to 4°.

In the median radial plane at each valley, the top of the valley can be offset relative to the laying ring, for example by a value of between 1.5 mm and 3 mm.

The obtuse angle formed, in the median radial plane at a primary valley, between the inner portion and the outer portion, is, for its part, of a value preferably between 130° and 175°, and for example of a value of approximately 160°.

The obtuse angle formed, in the radial plane median to a secondary valley, between the inner portion and the outer portion, has a value between 130° and 165°, and advantageously from 140° to 145° approximately.

The top of each valley is advantageously distant from the plane of the laying ring by a value between 10% and 15% - and e.g. approximately 12% - of the overall diameter of the bottom of the container.

The has an overall diameter, all the external portions join the periphery on the same junction plane, and the feet have a height, measured axially between the plane of the ring of laying and said junction plane, the value of which is between 15% and 25%, and preferably approximately 20%, of the overall diameter of the bottom.

• la FIG.1 est une vue de dessous en perspective d'un récipient muni d'un fond pétaloïde de faible hauteur ;
• la FIG.2 est une vue de dessous en perspective du fond de la FIG.1 , à plus grande échelle ;
• la FIG.3 est une vue en plan de dessous du fond du récipient de la FIG.2 ;
• la FIG.4 est une vue en plan de dessous de détail, à plus grande échelle, du fond de la FIG.3 prise dans le médaillon IV ;
• la FIG.5 est une section du fond de la FIG.3 , selon le plan de coupe V-V ;
• la FIG.6 est une section du fond de la FIG.3 , selon le plan de coupe VI-VI ;
• la FIG.7 est une section partielle du fond de la FIG.3 , selon le plan de coupe VII-VII ;
• la FIG.8 est une section partielle du fond de la FIG.3 , selon le plan de coupe VIII-VIII ;
• la FIG.9 est une section partielle du fond de la FIG.3 , selon le plan de coupe IX-IX ;
• la FIG.10 est une section partielle du fond de la FIG.3 , selon le plan de coupe X-X.

Other objects and advantages of the invention will appear in the light of the description of an embodiment, given below with reference to the appended drawings in which:

• the FIG.1 is a bottom perspective view of a container with a low petaloid bottom;
• the FIG.2 is a perspective bottom view of the bottom of the FIG.1 , on a larger scale ;
• the FIG.3 is a bottom plan view of the container bottom of the FIG.2 ;
• the FIG.4 is a detailed bottom plan view, on a larger scale, of the bottom of the FIG.3 taken in medallion IV;
• the FIG.5 is a section of the bottom of the FIG.3 , according to section plane VV;
• the FIG.6 is a section of the bottom of the FIG.3 , according to section plane VI-VI;
• the FIG.7 is a partial section of the bottom of the FIG.3 , according to section plane VII-VII;
• the FIG.8 is a partial section of the bottom of the FIG.3 , according to section plane VIII-VIII;
• the FIG.9 is a partial section of the bottom of the FIG.3 , according to section plane IX-IX;
• the FIG.10 is a partial section of the bottom of the FIG.3 , according to section plan XX.

On the FIG.1 is shown, in perspective from below, a container 1 - in this case a bottle - obtained by blow molding or stretch blow molding from a blank, such as a preform made of thermoplastic material, for example polyethylene terephthalate (PET), previously heated.

The container 1 extends along a main axis X and comprises a side wall called the body 2 , and a bottom 3 which extends and closes the body 2 at a lower end thereof.

The bottom 3 is petaloid, and comprises a bottom wall 4 of generally convex shape towards the outside of the container 1 (that is to say downwards when the container 1 is placed flat).

The bottom 3 has a central dome 5 which extends hollow towards the inside of the container 1 (that is to say that the dome 5 has a concavity facing the outside of the container 1 ). At its center, the dome 5 has a top 6. In the example illustrated, the top 6 carries, projecting axially, an injection molded disc, the material of which has remained substantially amorphous during the forming of the container 1. The dome 5 has the particular function of stretching the material at the center of the bottom, so as to increase its crystallinity and therefore its mechanical strength.

The dome 5 extends to a peripheral edge 7 (here of substantially circular contour when seen from below) by which it is connected to the wall 4 of the bottom. More precisely, the peripheral edge 7 forms a connection fillet of the dome 5 to the wall 4 of the bottom.

The bottom 3 also comprises a series of feet 8 which form protrusions projecting axially from the bottom wall 4 towards the outside of the container 1.

The feet 8 extend radially from the central dome 5 (and more precisely from its peripheral edge 7 ), up to a periphery 9 of the bottom 3 where the latter is connected to the body 2.

As is clearly visible on the FIG.2 and FIG.3 , the feet 8 are separated two by two by portions of the bottom wall 4 forming valleys 10 which extend radially in a star shape from the dome 5 to the periphery 9.

The valleys 10 extend hollow between the feet 8 which they separate two by two. The valleys 10 are substantially straight when viewed in a plane perpendicular to the main X axis (i.e. in the plane of the FIG.3 ).

Moreover, as is also visible the FIG.3 , the valleys 10 are advantageously slightly curved and have a width (measured perpendicular to the radius) which, from the dome 5 to the periphery 9 , first decreases and then increases.

As we clearly see on the FIG.2 and FIG.3 , the feet 8 are equal in number to the valleys 10. In the example illustrated, the bottom 3 comprises six feet 8 and six valleys 10 , regularly alternated and distributed in a star. This number is a good compromise; it could, however, be less (but greater than or equal to four), or greater (but preferably less than or equal to ten).

Each foot 8 has two substantially plane sides 11 which each laterally border a valley 10. As can be seen on the FIG.7 to FIG.10 , the sides 11 are not vertical (because the bottom 3 would then be difficult or even impossible to blow), but inclined by opening from the valley 10 outwards.

Each foot 8 also has a median face 12 which makes the junction between the sides 11. As illustrated in the FIG.3 , seen in a plane perpendicular to the main axis X , the median face 12 extends substantially radially.

Moreover, as illustrated in the FIG.5 , in a radial plane, the median face 12 has a curved profile with a concavity facing the outside of the container 1.

The most projecting part of each leg 8 , extending the median face 12 , forms an end face 13 of the leg 8. The end faces 13 of the legs 8 are coplanar and together form a ring 14 for laying, interrupted and flat section, by which the container 1 can rest on a flat surface (for example a table).

The laying ring 14 is connected to the body 2 via a structure having a connecting fillet comprising two parts 8A and 8B , connected at a junction 8C. Said structure will be described in more detail later.

As can be seen on the FIG.3 , the laying ring 14 (shown in this figure by a dot-and-dash circle), is set back radially with respect to the periphery 9.

As is clearly visible on the FIG.2 and FIG.3 , the feet 8 become thinner from the inside towards the outside of the container 1 (that is to say downwards), and widen from the central dome 5 towards the periphery 9.

Each valley 10 has an internal portion 15 which extends from the central dome 5 , and an external portion 16 which joins the periphery 9.

All the outer portions 16 join the periphery 9 at the same level, therefore on the same section or the same plane called the junction plane. The overall height of the bottom 3 is defined as being the distance, measured axially, between the plane of the laying ring 14 (in other words the end face 13 ) and the junction plane between the external portions 16 and the periphery 9. As will be indicated later, this height is referenced Q.

As illustrated on the FIG.5 and FIG.6 , the internal portion 15 and the external portion 16 are, in section in a radial plane median to the valley 10 , straight and together form an obtuse angle projecting towards the outside of the container 1.

The inner portion 15 and the outer portion 16 meet in a vertex 17 located plumb or in the immediate vicinity of the plumb of the laying ring 14 , that is to say that the top can be offset from the laying plane determined by the ring 14. According to a preferred embodiment, the top 17 is curved in any radial plane, and has a concavity facing the interior of the container 1.

It has been found that this shape increases the mechanical strength of the bottom 3 , in particular when the container 1 is pressurized.

• ∘ des vallées 10A primaires dont la portion interne, notée 15A, se raccorde au dôme 5 à hauteur du bord 7 périphérique de celui-ci ;
• ∘ des vallées 10B secondaires dont la portion interne, notée 15B, se raccorde au dôme 5 à distance de son bord 7 périphérique.

Furthermore, as illustrated in the drawings (and more particularly in the FIG.5 and on the FIG.6 ), the valleys 10 are subdivided into two groups of valleys 10 arranged alternately, namely:

• ∘ primary valleys 10A whose internal portion, denoted 15A , is connected to the dome 5 at the height of the peripheral edge 7 thereof;
• ∘ secondary valleys 10B whose internal portion, denoted 15B , is connected to the dome 5 at a distance from its peripheral edge 7 .

In other words, the inner portion 15B of the secondary valleys 10B is deeper, when measured axially, than the inner portion 15A of the primary valleys 10A . This difference in depth is clearly visible on the FIG.2 and to the left of the FIG.6 , where the primary valleys 10A are drawn in thin dashed lines while the secondary valleys 10B are drawn in bold solid lines.

A

l'angle, mesuré dans un plan radial médian à la vallée 10, entre la portion 16 externe de la vallée et tout plan perpendiculaire à l'axe X principal

B

la largeur, mesurée radialement, de l'anneau 14 de pose

C

le rayon de courbure, mesuré dans un plan radial, d'un congé de raccordement entre la face 12 médiane du pied 8 et l'anneau 14 de pose

D

le diamètre hors tout du fond 3, mesuré à la périphérie 9

E

le rayon de courbure, mesuré dans un plan radial, d'une première partie 8A du congé de raccordement entre l'anneau 14 de pose et le corps 2, ladite première partie 8A étant comprise entre l'anneau 14 de pose et la jonction 8C entre les parties 8A et 8b du congé de raccordement

E'

le rayon de courbure du sommet 17

F

la hauteur du dôme 5, mesurée axialement entre le bord 7 périphérique et le sommet 6

F'

la distance, mesurée axialement, entre le bord 7 périphérique du dôme 5 et le bord intérieur de la portion 15B interne de chaque vallée 10B secondaire, à sa jonction avec le dôme 5

G

l'angle, considéré dans un plan radial, entre l'axe X du corps 2 et la tangente à la première partie 8A du congé de raccordement, au niveau de la jonction 8C entre les parties 8A et 8b de ce congé de raccordement

H

la distance, mesurée axialement, entre, d'une part, une limite externe du bord 7 périphérique du dôme 5 et le plan de l'anneau 14 de pose

J

le diamètre de l'anneau 14 de pose, mesuré sur un bord interne de celui-ci

L

la distance, mesurée axialement, entre une limite interne du bord 7 périphérique du dôme 5 et le plan de l'anneau 14 de pose

M

la distance, mesurée axialement, entre le sommet 17 de chaque vallée 10 et le plan de l'anneau 14 de pose

O

le décalage, mesuré radialement, entre le sommet 17 de chaque vallée 10 et l'anneau 14 de pose

P

l'angle obtus formé, dans le plan radial médian à chaque vallée 10A primaire, entre la portion 15A interne et la portion 16 externe

P'

l'angle obtus formé, dans le plan radial médian à chaque vallée 10B secondaire, entre la portion 15B interne et la portion 16 externe

Q

la hauteur hors tout du fond 3, c'est-à-dire la distance, mesurée axialement, entre le plan de l'anneau 14 de pose et la jonction entre une portion 16 externe et la périphérie 9

R

l'ouverture angulaire entre les flancs 11, mesurée dans un plan transversal relativement plus éloigné du dôme 5, confondu avec le plan de coupe VIII-VIII, tel qu'illustré sur la FIG.8

S

l'ouverture angulaire entre les flancs 11, mesurée dans un plan transversal (c'est-à-dire perpendiculaire au rayon médian du pied 8) voisin du dôme 5, confondu avec le plan de coupe VII-VII, tel qu'illustré sur la FIG.7

T

le rayon hors tout, mesuré radialement, du dôme 5

U

l'ouverture angulaire entre les flancs 11, mesurée dans un plan transversal voisin de la périphérie, confondu avec le plan de coupe X-X, tel qu'illustré sur la FIG.10

V

l'ouverture angulaire entre les flancs 11, mesurée dans un plan transversal encore plus éloigné du dôme 5, confondu avec le plan de coupe IX-IX, tel qu'illustré sur la FIG.9

W

le rayon de courbure, mesuré dans un plan radial, de la face 12 médiane du pied 8

We now provide additional details on the dimensioning of the bottom 3. To this end, we note:

HAS

the angle, measured in a radial plane median to the valley 10 , between the outer portion 16 of the valley and any plane perpendicular to the main X axis

B

the width, measured radially, of the laying ring 14

VS

the radius of curvature, measured in a radial plane, of a fillet between the median face 12 of the foot 8 and the ring 14 of laying

D

the overall diameter of the bottom 3 , measured at the periphery 9

E

the radius of curvature, measured in a radial plane, of a first part 8A of the connecting fillet between the laying ring 14 and the body 2 , said first part 8A being between the laying ring 14 and the junction 8C between parts 8A and 8b of the fillet

E'

the radius of curvature of the vertex 17

F

the height of the dome 5 , measured axially between the peripheral edge 7 and the top 6

F'

the distance, measured axially, between the peripheral edge 7 of the dome 5 and the inner edge of the internal portion 15B of each secondary valley 10B , at its junction with the dome 5

G

the angle, considered in a radial plane, between the axis X of the body 2 and the tangent to the first part 8A of the fillet, at the level of the junction 8C between the parts 8A and 8b of this fillet

H

the distance, measured axially, between, on the one hand, an outer limit of the peripheral edge 7 of the dome 5 and the plane of the laying ring 14

J

the diameter of the laying ring 14 , measured on an internal edge thereof

L

the distance, measured axially, between an internal limit of the peripheral edge 7 of the dome 5 and the plane of the laying ring 14

M

the distance, measured axially, between the top 17 of each valley 10 and the plane of the laying ring 14

O

the offset, measured radially, between the apex 17 of each valley 10 and the laying ring 14

P

the obtuse angle formed, in the median radial plane at each primary valley 10A , between the inner portion 15A and the outer portion 16

P'

the obtuse angle formed, in the median radial plane at each secondary valley 10B , between the inner portion 15B and the outer portion 16

Q

the overall height of the bottom 3 , that is to say the distance, measured axially, between the plane of the laying ring 14 and the junction between an outer portion 16 and the periphery 9

R

the angular opening between the flanks 11 , measured in a transverse plane relatively farther from the dome 5 , coinciding with the cutting plane VIII-VIII, as illustrated in the FIG.8

S

the angular opening between the flanks 11 , measured in a transverse plane (that is to say perpendicular to the median radius of the foot 8 ) close to the dome 5 , coinciding with the cutting plane VII-VII, as illustrated on the FIG.7

T

the overall radius, measured radially, of dome 5

U

the angular opening between the flanks 11 , measured in a transverse plane close to the periphery, coinciding with the cutting plane XX, as illustrated in the FIG.10

V

the angular opening between the flanks 11 , measured in a transverse plane even further from the dome 5 , coinciding with the cutting plane IX-IX, as illustrated in the FIG.9

W

the radius of curvature, measured in a radial plane, of the median face 12 of the foot 8

The bottom 3 may be referred to as a “petaloid bottom” because of its structure consisting of alternating projecting feet 8 and recessed valleys 10 . However, its low Q height / D diameter ratio disqualifies it for carbonated applications (typically for soft drinks). This ratio is in fact less than or equal to 1/4.

A typical petaloid bottom would have such a ratio of about 1/2. The present bottom 3 , which can be called a “mini petaloid” because of its low height Q / diameter D ratio, is intended more for applications of the flat liquid type associated with the addition, immediately after filling and before capping , a drop of liquid nitrogen, the vaporization of which puts the contents of the container 1 under overpressure, this overpressure being less than or equal to 1.3 bar.

In this case, the height Q /diameter D ratio is advantageously between 0.15 and 0.25, and preferably of the order of 0.2.

According to an embodiment illustrated in the FIG.5 , in the primary valleys 10A , the internal portion 15A is inclined, with respect to any plane parallel to the plane of the laying ring 14 , towards the outside of the container 1. This negative inclination of the portion 15A is called "sloping". internal, advantageously between 2° and 10°.

According to an embodiment illustrated in the FIG.6 , in the secondary valleys 10B , the internal portion 15B is on the contrary inclined, with respect to any plane parallel to the plane of the laying ring 14 , towards the inside of the container 1 . This positive inclination of the internal portion 15B , advantageously between 5° and 30°, is called “tilt”.

As a variant, however, the internal portion 15A of the primary valleys 10A could, like the internal portion 15B of the secondary valleys 10B , be inclined, with respect to any plane parallel to the plane of the laying ring 14 , towards the inside of the container 1 , that is to say in incline, at an angle however less than or equal to 4°.

Thus, and as emerges from the joint reading of the FIG.3 , FIG.5 and FIG.6 , the bottom 3 has, in the example shown, valleys 10A and 10B whose internal portions 15A , 15B are alternately sloping ( FIG.5 ) and forward ( FIG.6 ). As we have already mentioned, the internal portions 15A of the primary valleys 10A open internally on the peripheral edge 7 of the central dome 5 , while the internal portions 15B of the secondary valleys 10B open internally at a distance from the peripheral edge 7 . This configuration increases the mechanical resistance of the bottom 3 when it is under pressure.

More specifically, and as mentioned in the table above, the internal portions 15B of the secondary valleys 10B open onto the dome 5 at a distance F' from the peripheral edge 7 thereof, between this peripheral edge 7 and the top 6 of the dome. Depending on the depth (that is to say the inclination) of the internal portions 15B of the secondary valleys 10B , this distance F' is advantageously between 20% and 70% of the total height F of the dome 5 : $$0.2\cdot F\le F\prime \le 0.7\cdot F$$

In the example shown, the distance F' is approximately 60% of the total height F of the dome 5 : $$F\prime \cong 0.6\cdot F$$

This configuration makes it possible to obtain a compromise between the structural rigidity of the bottom 3 due in particular to the depth of the internal portions 15B of the secondary valleys 10B , in particular in the vicinity of the center of the bottom 3 , and the good blowability of the latter (c ' that is to say its ability to be correctly formed during the blowing of the container 1), due in particular to the relatively shallow depth of the internal portions 15A in the vicinity of the center of the bottom 3.

Furthermore, as can also be seen in the FIG.5 and FIG.6 , in at least one of the valleys 10 (and preferably in all the valleys 10 ), the outer portion 16 is advantageously inclined, with respect to any plane parallel to the plane of the laying ring 14 , towards the inside of the container 1 , at an angle A. In other words, the outer portion 16 is sloping. The angle A of inclination of the outer portion 16 is preferably between 20° and 30°.

The angles P and P' are obtuse; they are therefore strictly greater than 90° and strictly less than 180°.

More specifically, as illustrated in the FIG.5 , the angle P is advantageously between 130° and 175°, and preferably around 160°.

As for the angle P' , illustrated on the FIG.6 , it is advantageously between 130° and 165°, and preferably from approximately 140° to 145°.

The width B of the laying ring 14 is advantageously between 0.4 mm and 1 mm, and preferably of the order of 0.5 mm.

The radius C of curvature is advantageously equal to approximately half the radius E.

The radius E is advantageously between 5 mm and 11 mm. In this case, it follows that the radius C is between 2.5 mm and 5 mm. The center of curvature of the radius E is located vertically to the laying ring 14 .

As indicated previously, the laying ring 14 is connected to the body 2 by means of a structure having a connecting fillet comprising two parts 8A and 8B. The radius E is that of the first part 8A , which is between the laying ring 14 and the junction 8C between the parts 8A and 8b of the fillet. This radius is constant or can vary very little.

The second part 8B of the fillet is between the junction 8C and the periphery 9 of the bottom 3 where the latter is connected to the body 2. This second part 8B has an evolving radius of curvature between the junction 8C and the peripheral edge 9 of the bottom 3.

The overall diameter D of the bottom 3 depends on the capacity of the container 1. For a container 1 with a capacity of 0.5 l, the diameter D can be approximately 65 mm (in this case, the radius E is advantageously about 6mm). For a container 1 with a capacity of 1.5 l, the diameter D can be approximately 90 mm (in this case, the radius E is advantageously approximately 9 mm).

The radius E' of the crown is advantageously between 5 mm and 11 mm. It can be equal to the radius E. In practice, like the radius E, the radius E' is a function of the capacity of the container 1. For a container 1 with a capacity of 0.5 l, the radius E' can be 6mm approx. For a container 1 with a capacity of 1.5 l, the radius E' can be approximately 9 mm.

The height F of the dome 5 is advantageously between 1 mm and 8 mm. In practice, this height F depends on the capacity of the container 1. For a container 1 with a capacity of 0.5 l, the height F can be approximately 2 mm. For a container 1 with a capacity of 1.5 l, the height may be approximately 7.5 mm. In this case, the distance F' is advantageously approximately 4.5 mm.

The angle G is advantageously between 20° and 40°. It is recalled that this is the angle considered in a radial plane, between the axis X of the body 2 and the tangent to the first part 8A of the fillet, at the level of the junction 8C between the parts 8A and 8b of this fillet. In practice, the angle G is a function of the capacity of the container 1 and, in particular, of its diameter D. The value of the angle G , according to the diameter D of the container and the radius E of curvature of the first part 8A of the fillet, determines the position of the junction 8C between the two parts 8A and 8B of the fillet connecting the ring 14 to the body 2. For a container 1 with a capacity of 0.5 l, the angle G can be 25° approx. For a container 1 with a capacity of 1.5 l, the angle G can be approximately 35°.

The distance H is advantageously linked to the overall diameter D of the bottom 3. More precisely, the distance H is preferably between 10% and 15% (and for example approximately 12%) of the diameter D.

The diameter J is advantageously between 65% and 75% (and for example approximately 70%) of the diameter D.

The distance L is advantageously between 50% and 85% (and for example approximately 70%) of the overall height Q of the bottom 3.

The distance M is advantageously a function of the overall diameter D of the bottom 3. More precisely, the distance M is advantageously between 10% and 15% (and for example approximately 12%) of the diameter D.

The offset O can be zero and, in this case, the apex 17 is located directly above the laying ring 14 ; it can also be positive (i.e. that the top 17 is offset radially, with respect to the laying ring 14 , towards the outside of the container 1 ), or on the contrary negative (that is to say that the top 17 is offset radially, with respect to the laying ring 14 , towards the inside of the container 1 ). In both cases, the offset value O is small compared to the diameter D.

Offset O can be indexed to radius E , e.g. in a ratio of 1 to 3, that is to say that the O/E ratio is approximately 1/3.

Considering the values already provided for E , it is understood that the offset O is between 1.5 mm and 3 mm.

In addition, the overall radius T of the dome 5 is advantageously between 5 mm and 15 mm. In practice, this radius T depends on the capacity of the container 1 . For a container 1 with a capacity of 0.5 l, the radius T is thus, for example, approximately 7 mm. For a container 1 with a capacity of 1.5 l, the radius T is eg. approximately 13mm.

Finally, as can be seen from the FIG.7 to FIG.10 , the angular opening of the sides 11 is variable. More precisely, the angular opening of the sides 11 decreases from the inside towards the outside of the bottom 3 (that is to say from the axis X towards the periphery 9 ), the angular opening S being greater than the angular opening R , which is in turn greater than the angular opening V , itself greater than the angular opening U , which means that the sides 11 are closing from the dome 5 towards the periphery 9.

This variation in angular opening makes it possible to widen the feet 8 towards the periphery 9 , to the benefit of the stability of the container 1 , and the resistance of the feet 8 , in particular during the palletization of the container 1.

Under the effect of pressure in the container 1 , the angle P tends to deform while closing. As the top 17 is plumb or in the immediate vicinity of the plumb of the laying ring 14 , the flanks 11 , which have their greatest height at this location (measured axially, combined with the distance M ), absorb this deformation without deforming too much in turn, so that the general deformation of the bottom 3 is small, and it therefore resists pressure well. The concave shape of the median face 12 , as well as the alternation of relatively shallow primary valleys 10A and deeper secondary valleys 10B , seem to contribute to this rigidity.

Tests carried out on the container 1 show that the most significant deformations are located on the dome 5 , whose curved shape resists pressure particularly well, while the zones peripheral to the dome 5 (valleys 10 , feet 8 ) undergo only slight deformations.

Claims (17)

1. Plastic container (1) comprising a body (2) which extends along a main axis (X) and a petaloid bottom (3) extending the body (2), this bottom (3) comprising:

   - a bottom wall (4) with an overall shape which is convex towards the outside of the container (1),

   - a central dome (5) which is in the form of a recess towards the inside of the container (1) and extends from a central apex (6) to a peripheral edge (7) via which the dome (5) is connected to the bottom wall (4), and

   - at least four feet (8) which form protuberances from the bottom wall (4) towards the outside of the container (1), separated in pairs by portions of the bottom wall (4) forming at least four recessed valleys (10) which extend radially from a central dome (5) of the bottom (3) to a periphery (9) thereof,

   each foot (8) having two flanks (11), each bordering a valley (10) and a median face (12) which, in a radial plane, has a curved profile with a concavity facing the outside of the container (1) and is extended by an end face (13), the end faces jointly forming a standing ring (14) which has a planar section and is interrupted in line with each valley (10);

   each valley (10) has an internal portion (15, 15A, 15B) which extends from the central dome (5) and an external portion (16) which meets the periphery (9) in the extension of the internal portion (15, 15A, 15B);

   the bottom (3) comprises two groups of valleys (10) arranged in alternation:

   o primary valleys (10A), the internal portion (15A) of which is connected to the dome (5) at the height of the peripheral edge (7) thereof;

   o secondary valleys (10B), the internal portion (15B) of which is connected to the dome (5) between the peripheral edge (7) and the central apex (6) of the dome at a distance (F') from the peripheral edge (7),

   characterized in that the internal portion (15, 15A, 15B) and the external portion (16) are, in section in a radial plane which is central in relation to the valley (10), straight and together form an obtuse angle (P) salient towards the outside of the container (1) and meet at an apex (17) located in vertical alignment with or in direct proximity to vertical alignment with the standing ring (14) .
2. Container (1) according to Claim 1, characterized in that the dome has a height (F), measured axially between its peripheral edge (7) and its apex (6) and, in the secondary valleys (10B), the internal portion (15B) is connected to the dome (5) at a distance (F') from the peripheral edge (7) of between 20% and 70% of said height (F) of the dome.
3. Container (1) according to Claim 1 or Claim 2, characterized in that, in the secondary valleys (10B), the internal portion (15B) is inclined, with respect to any plane parallel to the plane of the standing ring (14), towards the inside of the container (1).
4. Container (1) according to Claim 3, characterized in that the angle of inclination of the internal portion (15B) of the secondary valleys (10B) is between 5° and 30°.
5. Container (1) according to one of the preceding claims, characterized in that, in the primary valleys (10A), the internal portion (15A) is inclined, with respect to any plane parallel to the plane of the standing ring (14), towards the outside of the container (1).
6. Container (1) according to Claim 5, characterized in that the angle of inclination of the internal portion (15A) of the primary valleys (10A) is between 2° and 10°.
7. Container (1) according to one of Claims 1 to 4, characterized in that, in the primary valleys (10A), the internal portion (15A) is inclined, with respect to any plane parallel to the plane of the standing ring (14), towards the inside of the container (1) by an angle of less than or equal to 4°.
8. Container (1) according to one of the preceding claims, characterized in that, in the radial plane which is central in relation to each valley (10), the apex (17) of the valley (10) is offset with respect to the standing ring (14).
9. Container (1) according to Claim 8, characterized in that the apex (17) is offset with respect to the standing ring (14) by a value (O) of between 1.5 mm and 3 mm.
10. Container (1) according to one of the preceding claims, characterized in that the obtuse angle (P) formed, in the radial plane which is central in relation to a primary valley (10A), between its internal portion (15A) and its external portion (16), has a value of between 130° and 175°.
11. Container (1) according to Claim 10, characterized in that the obtuse angle (P) formed, in the radial plane which is central to each primary valley (10A), between the internal portion (15) and the external portion (16), has a value (P) of approximately 160°.
12. Container (1) according to one of the preceding claims, characterized in that the obtuse angle (P') formed, in the radial plane which is central in relation to a secondary valley (10B), between its internal portion (15B) and its external portion (16), has a value of between 130° and 165°.
13. Container (1) according to one of the preceding claims, characterized in that the obtuse angle (P') formed, in the radial plane which is central to a secondary valley (10B), between its internal portion (15B) and its external portion (16), has a value of approximately 140° to 145°.
14. Container (1) according to one of the preceding claims, characterized in that, the bottom (3) of the container having an overall diameter (D), the apex (17) of the valley (10) is spaced apart from the plane of the standing ring (14) by a value (M) of between 10% and 15% of said diameter.
15. Container (1) according to Claim 14, characterized in that the distance (M) from the apex (17) of the valley (10) to the plane of the standing ring (14) is approximately 12% of the overall diameter (12) of the bottom (3).
16. Container (1) according to one of the preceding claims, characterized in that the bottom (3) has an overall diameter (D), all of the external portions (16) meet the periphery (9) in one and the same joining plane, and the feet have a height (Q), measured axially between the plane of the standing ring (14) and said joining plane, with a value of between 15% and 25% of said diameter (D).
17. Container (1) according to Claim 16, characterized in that the height (Q) of the feet (8) has a value of approximately 20% of the overall diameter (D) of the bottom (3).

Images