EP4074614B1 - Plastic container with flat bottom - Google Patents

Description

The field of the invention is that of the design and manufacture of containers obtained by blow molding or stretch-blow molding of a plastic material blank, such as PET (polyethylene terephthalate).

A blank corresponds to a preform or an intermediate stage of the container being manufactured.

The invention relates more particularly to the manufacture of flat containers, that is to say containers having a laterally flattened body and an oval bottom for example.

These containers can be characterized by the shape of their bottom which has an oblong contour according to a bottom view of the container.

This type of container presents an inherent risk of instability in an upright position, and a risk of tipping around an axis parallel to the long length of the bottom.

In practice, it is found that the natural instability (due to the flat shape) of such a container is frequently coupled with an instability due to defects in the quality of impression taking of the bottom.

One of the causes of this instability is the difference in distribution of the plastic material occurring during the blow molding of the blank.

Indeed, during the formation of the bottom of the container, the plastic material of the blank must stretch in the mold and be distributed to match the shape of the bottom of the mold. In the case of a flat container, that is to say a container which has an oval bottom, the plastic material of the blank first reaches the central part of the bottom during its stretching, then stretches and reaches faster and in greater proportion the lateral ends of the bottom (the two opposite edges of the bottom which are closest to a central point of the bottom) than the longitudinal ends of the bottom (the two edges of the facing bottom which are farthest from the central point of the bottom), this bottom being oval, that is to say that its largest dimension, which is in a first direction, is significantly higher than its dimension in the direction perpendicular to this first direction.

There is thus produced a difference in the distribution of the plastic material of the blank to form the oval bottom. This difference in distribution is likely to cause formation defects or defects in structural resistance or material distribution resulting in the instability of the container placed on its bottom, due to the bottom not being sufficiently flat.

There are solutions for obtaining an oval bottom of a flattened container which is not unstable.

A first example of the prior art, illustrated by figure 1 , has a bottom of a flat container 91 according to a cross-sectional view of the bottom placed on a support 93, which shows that the bottom is provided with "feet" 92. A container 91 is thus observed, provided with feet 92 used for place the container 91 stably on a support 93.

Although this is only slightly visible, this solution can be described as unsightly because of the feet 92 and that there is no continuous, one-piece laying plane of the bottle on the support 93.

In other words, the seat of the container, when it is placed vertically on a support 93 and is in contact with this support 93, is not continuous along the perimeter of the bottom of the container 91.

Obtaining a bottom provided with a continuous laying plane, or at the very least essentially continuous, is a desired objective.

The document FR 3005034 discloses a container of oblong transverse shape provided with a continuous seat.

Flat containers provided with a continuous laying plane can be obtained by blowing a blank into a mold accompanied by boxing the bottom. In this case, the container cavity mold comprises a mobile boxing insert in the bottom of the mold. Once the container has been formed or during the formation of this container, the boxing insert deforms the bottom, which makes it possible to obtain a continuous laying plane.

This technique requires the use of a boxing insert and it is sought to obtain such a continuous laying plane without implementing a boxing technique, that is to say, obtaining a continuous laying plane only by blowing or stretch-blow molding a blank in a mould.

The object of the invention is in particular to overcome the drawbacks of the prior art.

More specifically, the invention aims to provide a flattened container whose oval bottom has the ability, by its shape, to have a continuous laying plane and to present significant stability when it is placed upright on its bottom.

The invention also aims to provide such a container which can be obtained using a simple manufacturing technique, not necessarily requiring the use of a boxing insert.

These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to a plastic container, provided with a body and a bottom in the extension of the body at a lower end. of the body, the bottom presenting a oblong curved contour and comprising: a seat forming a laying plane of the container, the laying plane having an oblong curved shape extending along a longitudinal median axis and a transverse median axis, the seat having a width, of a value w, between its distal ends along the transverse midline; a vault extending from the seat to a central area of the bottom, the vault defining a concavity from the outside of the container; the container having a central axis on which the central zone is centered, the container where the seat has reductions in width each located on one side of the longitudinal median axis, at least at the level of the intersection between the seat and the transverse median axis, and where the vault has for each reduction in width of the seat, on the one hand, a recess filling said reduction in width of the seat and forming a concavity from the outside of the container, and, on the other hand, a curved portion extending directly from said recess in the direction of the central zone, and having, in a section plane passing through the central axis and the transverse axis, a section in the form of an arc of a circle inscribing in a circle whose center is located at a distance, of a value dc, from the central axis along the transverse median axis, with 0.1w ≤ of ≤ 0.3w .

It could be observed unexpectedly that under 10%, the curve is not sufficiently pronounced. Above 30%, the curve becomes too abrupt and risks penalizing the formation of the base of the container.

Thanks to the shape of its bottom, the container according to the invention has significant stability when it is placed upright on its bottom, while being able to be obtained by means of a simple blow molding or a stretch-blow molding of a blank in a mold in the shape of the container, with no moving parts.

It has been identified by the inventors that the strong curvature of the curved portions, in particular compared to the conventional curvatures of the bottoms of the prior art at the level of a median transverse sectional plane, coupled with the recesses, notably improves the good formation of the containers of the type according to the invention.

Indeed, during the blow molding of the container, the reliefs of the bottom of the mold corresponding to the curved portions make it possible to slow down the expansion of the plastic material of the blank on either side of the central zone of the bottom, along the axis transverse median, while the expansion of the plastic material is not hindered on either side of the central zone along the longitudinal median axis.

In other words, the stretching of the plastic material during the blowing is contained by the presence of the reliefs of the bottom of the mold resulting from the curved portions to avoid too much accumulation of plastic material at the lateral ends (long sides) of the bottom of the container compared to its longitudinal ends (short sides).

The reliefs of the bottom of the mold corresponding to the two recesses, behind each curved portion, make it possible to ensure the correct distribution, in the parts adjacent to the recesses, of the plastic material having been previously slowed down by the reliefs of the bottom of the mold resulting from the curved portions.

These recesses are complementary to the curved portions in that they make it possible to prevent, during the formation of the bottom of the container, a surplus of plastic material from reaching the level of the seat and causing instability of the container, and Contribute to the good resistance of the support of the bottom vis-à-vis the risk of subsidence after the latter has been formed.

This better distribution of the material at the level of the bottom, permitted both by the curved portions and by the recesses, contributes to the natural stability of the container obtained when the latter is placed upright on its bottom.

According to an advantageous variant embodiment, the vault has, between the central zone and a reduction in the width of the seat, at least one bead extending longitudinally and forming, from the outside of the container, a concavity in the vault.

The beads participate in slowing down the expansion of the plastic material during the blow molding of the container.

According to an advantageous characteristic, the bead has a proximal front face of the central zone, a distal rear face of the central zone, and, between them, a plate, the rear face curving in the direction of the seat, the rear face forming all or part of one of the curved portions.

The reliefs of the bottom of the mold corresponding to this shape of the beads make it possible to effectively slow down the progression of the plastic material during the forming of the container. This progression of the plastic material is significantly slowed down by the relief corresponding to the front face of the bead, slowed down less significantly by the relief corresponding to the plate, and then this progression is continued and accompanied by means of the relief corresponding to the rear face which curves towards the seat.

• une distance, d'une valeur d, le long de l'axe médian transversal entre le milieu du plateau de chaque bourrelet et l'axe central ;
• une distance, d'une valeur l, entre l'axe central et chaque extrémité distale de l'assise le long de l'axe médian transversal ;

avec 40% l ≤ d ≤ 65% l, préférentiellement avec d = 50% I.Advantageously, according to a view from below of the bottom, the bottom has:

• a distance, with a value d, along the transverse median axis between the middle of the plate of each bead and the central axis;
• a distance, of a value l, between the central axis and each distal end of the seat the along the transverse midline;

with 40% l ≤ d ≤ 65% l, preferably with d = 50% I.

As explained previously, the reliefs of the bottom of the mold corresponding to each bead make it possible to retain the plastic material in the course of expansion and help to unroll this material well to form the bottom. Also, the reliefs of the mold corresponding to the beads increase the development of the bottom shape along the transverse median axis.

If the “d” value is less than 40% of the “l” value, then the shape of each bead is too prominent and will interfere with the stretching of the plastic material through the “wall” thus generated.

If the value of "d" is greater than 65% of the value of "l", then the beads penalize the formation of the seat.

With a value “d” equal to 50% of the value “l”, then the position of each bead optimizes the effect of the reliefs of the bottom of the mold corresponding to these beads.

According to an advantageous characteristic, the bead, at the level of the front face, has a height of a value h with 0.7 mm≤h≤2.3 mm, and preferably with h=1.5 mm.

The relief of the mold corresponding to the height of the front face, of the plate, and in other words the height of each bead, contributes to increasing the length of the developed.

Below 0.7 mm, the relief of the mold corresponding to each bead no longer has any technical effect and beyond 2.3 mm the effect of retention of the material during its expansion becomes too great.

With h=1.5 mm, an advantageous ratio is obtained between the presence of the barrier effect and the absence of excessive material retention.

According to a preferred characteristic, the bead has an offset inserted between its plate and its rear face, and, according to a cross section, the front face, the plate and the offset together create a crenellated shape, and in that, at the level of the offset , the bead has a height, of a value g, with g<h, and preferably with g=0.33h.

The offset makes it possible to increase the development presented by the relief of the bottom of the mold corresponding to each bead. In addition, it has been observed that the reliefs of the mold corresponding to the offsets help to spread the plastic material well during the blow molding.

With g = 33% h, the height of the offset creates a particularly advantageous technical effect.

Also, the presence of the offset between the plate and its rear face makes it possible to better hold the specific shape of each bead. This avoids a collapse of the plastic material following the blow molding of the container.

• une portion initiale adjacente au plateau, la portion initiale s'étendant parallèlement à la voûte ;
• une portion terminale adjacente à l'assise, la portion terminale présentant à son intersection avec l'assise un angle, d'une valeur a, avec une droite perpendiculaire à l'axe médian transversal et inscrite dans la coupe transversale médiane du fond,

avec 12,5° ≤ a ≤ 35°, préférentiellement 17,5° ≤ a ≤ 26°.Preferably, for each bead and according to a median cross-section of the bottom, the rear face has:

• an initial portion adjacent to the plate, the initial portion extending parallel to the vault;
• an end portion adjacent to the seat, the end portion having at its intersection with the seat an angle, of a value a, with a straight line perpendicular to the transverse median axis and inscribed in the median cross section of the bottom,

with 12.5°≤a≤35°, preferably 17.5°≤a≤26°.

The shape of the rear face is then optimized to allow an optimized distribution of the plastic material along the relief of the mold corresponding to the rear faces of the beads, then at the level of the seat.

In certain embodiments, the bottom comprises, between the beads which face each other, centered on the central zone of the bottom, a dome, the profile of which, parallel to the laying plane, is an oblong shape elongated along the axis ML and which creates, from the outside of the container, a concavity in the vault.

Such a dome, also designated by the English expression “push-up”, makes it possible to help stretch the plastic material when it reaches the bottom of the mould.

Advantageously, the seat has a width, of a value w, between the distal ends of the seat along the transverse median axis,
with 30% w ≤ y ≤ 45% w.

If y < 30% w, then the relief of the bottom of the mold corresponding to the dome does not produce the desired effect.

If y > 45% w, then the dome takes up too much space.

According to an advantageous characteristic, the seat has a length, of a value t, between its distal ends along the longitudinal median axis,
with 25% t ≤ x ≤ 70% t, preferably with x = 54% t.

If the x value is less than 25% of the t value, then the stretching of the plastic material to both ends of the arch along the longitudinal axis may not take place correctly.

If the value x is greater than 70% of the value t, then the plastic material risks not reaching the seat in sufficient quantity at the level of its lateral parts.

According to an advantageous characteristic, the vault comprises four branches framing each bead two by two, each branch extending along an axis of extension from the dome to the seat, forming, from the outside of the container, a protrusion at from the vault, and for each bead, the top has a length, with a value p, along the longitudinal median axis, and the seat has a length, with a value t, between its distal ends along the longitudinal median axis, with 20% t ≤ p ≤ 40% t, preferably with p = 25% t.

The branches contribute to a good distribution of the plastic material, by increasing the development between the central point and the periphery of the bottom around the beads, as well as to stiffen the bottom.

The adapted width of the beads makes it possible to accommodate the branches on the bottom.

In certain cases, according to a view from below of the bottom, each axis of extension of a branch forms an angle with the transverse median axis, of a value b, with 50° ≤ b ≤ 63°, preferentially with b = 57°, and the axes of extension of two branches facing the longitudinal median axis intersect on the longitudinal median axis at a point, the two points being spaced from each other by a distance, with a value z, with 0.12≤z/t≤0.35, and preferably with z/t=0.27.

If the value b is greater than 63°, the branches are then too far apart with respect to the transverse central axis, and the plastic material cannot be stretched sufficiently to reach the ends of the seat along the central axis longitudinal.

If the value b is less than 50°, then the arms are too tight with respect to the transverse median axis and there is too much amorphous material on the seat at the level of its long sides, thus generating stability problems.

According to another variant embodiment in which the container does not include a branch, for each bead, the plate has a length, of a value p, along the longitudinal median axis, and the seat a length, of a value t, between its distal ends along the longitudinal median axis, with 40% t ≤ p ≤ 65% t, preferably with p = 55% t.

Thanks to such a length of the beads, the technical effects of the reliefs of the mold corresponding to these beads are improved.

Beyond 65% t, the length of the plate of each bead is such that the plastic material does not unroll sufficiently in the direction of the corners of the bottom.

Below 40% t, the plastic material reaches the corners too quickly and an effect of instability may occur due to poor distribution of the plastic material at these locations.

According to a second preferred design in which the arch does not have a bead, the bottom comprises, between the beads which face each other, centered on the central zone of the bottom, a dome, the profile of which, parallel to the laying plane, is a oblong shape elongated along the axis ML and which creates, from the outside of the container, a concavity in the vault, each curved portion extending to the dome.

It has been found that this design makes it possible to obtain a container with a good distribution of the plastic material at the level of its bottom, and whose bottom has an increased resistance against the phenomenon of sagging.

Advantageously, the dome has, along the longitudinal median axis, a maximum length, of a value x, along the transverse median axis, a maximum width (Y), of a value y, with 2 y ≤ x ≤ 3, 5 y, preferably with 2.4y ≤ x ≤ 3 y.

With x < 2 y the dome is inefficient.

On the contrary, if x > 3.5 y then the dome occupies too much space and generates problems at the level of the laying plane.

The material stretching effect provided by the dome is particularly advantageous with the ratio x = between 2.4y and 3.0y.

In some embodiments, the curved portion has a grainy texture.

In this way, when the plastic material is stretched, it slides less easily at the level of the relief of the mold corresponding to the curved portions, which makes it possible to obtain a better distribution of the material.

In addition, difficult demoulding of the plastic material on the relief of the mold bottoms corresponding to the curved portions is avoided, which produces an improvement in the way in which the plastic material stretches at the level of the beads.

Finally, this grainy texture makes it possible to mask any defects that may occur in this area.

According to a possible additional characteristic, each recess has a length, with a value zero, along the longitudinal median axis, the seat has a length, with a value t, between its distal ends along the median axis longitudinal, with 65% t ≤ e ≤ 75% t, preferably with e = 70% t

The main effect of the recesses is to avoid that, if the container is too heavy, there is then a subsidence of the bottom on the laying plane, and more precisely a subsidence of the amorphous material. The recesses thus make it possible to mask this sagging and prevent this sagging reaching the laying plane and causing a stability problem.

If e < 65% t, then there is a risk that instability will occur because the material is less stretched on the relief of the bottom of the mold corresponding to the recesses.

If e > 75% t, then the length of the reliefs of the mold corresponding to each offset does not make it possible to sufficiently feed the ends of the plastic bottom.

According to a possible additional characteristic, for each bead, the plate has a length, with a value p, along the longitudinal median axis, and the seat has a length, with a value t, between its distal ends along the longitudinal median axis, with 40% t ≤ p ≤ 65% t, preferably with p = 55% t.

Thanks to such a length of the beads, the technical effects of the reliefs of the mold corresponding to these beads are improved.

Beyond 65% t, the length of the plate of each bead is such that the plastic material does not unroll sufficiently in the direction of the corners of the bottom.

Below 40% t, the plastic material reaches the corners too quickly and an effect of instability may occur due to poor distribution of the plastic material at these locations.

Advantageously, in the presence of the beads, and along the transverse median axis, each reduction in width of the seat has a width, of a value u, the seat having a residual width, of a value o,
with 10% (o+u) ≤ u ≤ o, preferably with u = o.

If u < 10% (o+u) a high risk of instability appears.

If u > o, the seat cannot be properly formed due to insufficient stretching of the plastic material.

The invention also relates to a mold for the manufacture of a container by blow molding or stretch-blow molding of a plastic material blank, the mold comprising a mold base having an upper forming surface which corresponds to the imprint of the bottom of the container as described above.

• [Fig. 1] la figure 1 est une représentation schématique selon une vue en coupe longitudinale d'un fond d'un récipient selon l'art antérieur ;
• [Fig. 2] la figure 2 est une représentation en perspective d'un récipient plat selon un premier mode de réalisation, présentant un médaillon d'un détail à échelle agrandie, illustrant plus spécifiquement un fond du récipient ;
• [Fig. 3] la figure 3 est une vue en coupe longitudinale du fond du récipient du premier mode de réalisation ;
• [Fig. 4] la figure 4 est une vue du dessous du fond selon le premier mode de réalisation ;
• [Fig. 5] la figure 5 est une vue du dessous du fond d'un deuxième mode de réalisation, dans lequel le fond est pourvu de branches ;
• [Fig. 6] la figure 6 est une vue en section selon un plan longitudinal du fond du second mode de réalisation ;
• [Fig. 7] la figure 7 est une vue en section selon un plan transversal du fond du deuxième mode de réalisation ;
• [Fig. 8] la figure 8 est une vue en perspective du fond du deuxième mode de réalisation comprenant un médaillon de détail à échelle agrandie, illustrant plus spécifiquement une branche du fond ;
• [Fig. 9] la figure 9 est une représentation schématique selon une section transversale du fond du deuxième mode de réalisation illustrant la répartition de la matière plastique grâce à la forme du fond ;
• [Fig. 10] la figure 10 est une vue du dessous du fond selon un troisième mode de réalisation ;
• [Fig. 11] la figure 11 est une vue en section selon un plan transversal du fond du troisième mode de réalisation ;
• [Fig. 12] la figure 12 est une vue en section selon un plan longitudinal du fond du troisième mode de réalisation.

Other characteristics and advantages of the invention will appear more clearly on reading the following description of various preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and the appended drawings, among which:

• [ Fig. 1 ] there figure 1 is a schematic representation according to a view in longitudinal section of a bottom of a container according to the prior art;
• [ Fig. 2 ] there figure 2 is a representation in perspective of a flat container according to a first embodiment, presenting a medallion of a detail on an enlarged scale, illustrating more specifically a bottom of the container;
• [ Fig. 3 ] there picture 3 is a longitudinal sectional view of the bottom of the container of the first embodiment;
• [ Fig. 4 ] there figure 4 is a bottom view of the bottom according to the first embodiment;
• [ Fig. 5 ] there figure 5 is a view from below of the bottom of a second embodiment, in which the bottom is provided with branches;
• [ Fig. 6 ] there figure 6 is a sectional view along a longitudinal plane of the bottom of the second embodiment;
• [ Fig. 7 ] there figure 7 is a cross-sectional view along a transverse plane of the bottom of the second embodiment;
• [ Fig. 8 ] there figure 8 is a perspective view of the back of the second embodiment including a detail medallion on an enlarged scale, more specifically illustrating a branch of the back;
• [ Fig. 9 ] there figure 9 is a schematic representation according to a cross section of the bottom of the second embodiment illustrating the distribution of the plastic material due to the shape of the bottom;
• [ Fig. 10 ] there figure 10 is a bottom view of the bottom according to a third embodiment;
• [ Fig. 11 ] there figure 11 is a sectional view along a transverse plane of the bottom of the third embodiment;
• [ Fig. 12 ] there figure 12 is a sectional view along a longitudinal plane of the bottom of the third embodiment.

With reference to figures 2 to 12 , a container 1 according to the invention is shown.

The following description of the characteristics of the container 1 according to the invention also applies to the characteristics of a mold making it possible to manufacture this container 1, understanding that the mold has an imprint intended to give its final shape to the container and of complementary shape.

The mold is a mold for the manufacture by blow molding or stretch-blow molding of a plastic blank. To this end, the mold according to the invention comprises a mold bottom which has an upper surface complementary to the imprint of a bottom of the container 1 as described below.

The container 1 according to the invention is a plastic container. More specifically, it is a polyethylene terephthalate container.

This container 1 is provided with a body 11 and a bottom 12 in the extension of the body 11 at a lower end of the body 11.

The container 1 according to the invention is a so-called “flat” container.

As illustrated by the figure 2 , 4 , 5 , And 10 the bottom 12 has, in a bottom view, an oblong curved contour.

In other words, the container 1 has smaller dimensions in its width than in its length. The bottom 12 thus comprises two long sides and two short sides.

• une assise 21 ;
• une voûte 22 s'étendant depuis l'assise 21 jusqu'à une zone centrale 23 du fond 12.

According to the present embodiments illustrated by the figures 2 to 12 , the bottom 12 comprises:

• a seat 21;
• a vault 22 extending from the seat 21 to a central zone 23 of the bottom 12.

The container 1 has a central axis C. The body 11 of the container extends along the central axis C from the bottom 12.

The central zone 23 of the bottom 12 is more specifically centered on the central axis C.

The arch 22 delimits a concavity from the outside of the container 1.

Moreover, according to the present embodiments of the figures 2 to 12 , the bottom 1 comprises, between the beads 3 which face each other, centered on the central zone 23 of the bottom 12, a dome 5, the profile of which, parallel to the laying plane, is an oblong shape elongated along the axis ML and which creates, from the outside of the container 1, a concavity in the vault 12, each curved portion 220 extending to the dome 5.

The seat 21 for its part forms a laying plane 210 of the container 1 as illustrated by the picture 3 .

This laying plane 210 has an oblong curved shape. The shape adopted by the laying plane 210 can also be described as oval.

Advantageously, the shape of the laying plane 210 is closed as is the case in the embodiments illustrated by the figures 2 to 9 . In other words, the laying plane of the container 1 presented by the seat 21 is continuous, that is to say that all around the bottom 12 when the container 1 is placed on a support, the entire seat is in contact with the support.

With reference to figures 4 to 7 , And 10 to 12 , the laying plane 210 formed by the seat 21 extends along a longitudinal center axis ML and a transverse center axis MT.

The longitudinal central axis ML and the transverse central axis MT intersect along the central axis C of the container 1.

According to the embodiment illustrated by the figures 10 to 12 , the laying plane 210 is not closed. Indeed, the seat 21 has two constrictions located at the ends of the seat along the longitudinal center axis ML.

The seat 21 has a length T, of a value t, between its distal ends along the longitudinal median axis ML, that is to say at the meeting of the longitudinal median axis ML with an outer contour 211 of seat 21.

The seat 21 also has a width W, of a value w, between the distal ends along the transverse median axis MT, that is to say at the meeting of the transverse median axis MT with the contour exterior 211 of the seat 21.

More generally, the bottom 12, according to a bottom view as illustrated by the figure 4 And 5 , extends along the longitudinal center axis ML and along the transverse center axis MT.

This bottom 12 has a larger dimension along the longitudinal center axis ML than along the transverse center axis MT, thus giving the laying plane an oblong curved shape.

For each of the present embodiments of the figures 2 to 12 , the bottom 12 of the container 1 according to the invention has a planar symmetry along a first plane in which is inscribed the transverse median axis MT and the central axis C of the container 1, and a planar symmetry along a second plane in which is inscribes the longitudinal median axis ML and the central axis C of the container 1.

According to the principle of the invention and with reference to the figure 2 , 4 , 5 , 7 , 10 And 11 , the seat 21 has reductions in width each located on one side of the longitudinal centerline (ML). Each reduction in width extends longitudinally at least opposite the central zone 23 along the transverse median axis MT, each on one side of the longitudinal median axis ML. In other words, these reductions in width extend along the two long sides of the bottom 12 along the longitudinal central axis ML, on either side of the transverse central axis MT, and at least on one distance corresponding to an orthogonal projection of the central zone 23 on the longitudinal median axis ML.

• un décrochement 4 comblant ladite réduction de largeur de l'assise 21 ;
• une portion courbe 220 s'étendant directement depuis le décrochement 4 en direction de la zone centrale 23.

In addition, the arch 22 has for each reduction in width of the seat 21:

• a recess 4 filling said reduction in width of the seat 21;
• a curved portion 220 extending directly from the recess 4 towards the central zone 23.

The recesses 4 each delimit, according to a cross section, a cavity from the outside of the container 1.

As illustrated more specifically by the figure 7 And 11 , each curved portion 220 extends directly from said recess 4 in the direction of the central zone 23, and has, in a section plane passing through the central axis C and the transverse axis MT, an arcuate section s inscribed in a circle Ce whose center is located at a distance DC, of a value dc, from the central axis C, measured along the transverse median axis MT.

Each circle Ce has a radius Rc which may for example be equal to approximately 5.6 mm.

These curved portions 220 fit, still according to the views of the figure 7 And 11 , in trapezoids whose small bases are oriented towards the central zone and whose large bases are oriented towards the recesses 4.

The curved portions 220 correspond to parts of the bottom 12 having an accentuated curvature from the recess and in the direction of the central part 23 with respect to conventional vaults according to the prior art.

As illustrated by the two embodiments represented by the figure 2 , 4 , 5 And 7 , the arch 22 has two beads 3, each bead 3 incorporating, as detailed below, a curved portion 220.

With reference only to the second embodiment illustrated by the figure 5 , the vault 22 further comprises four branches flanking each bead 3 in pairs.

According to figure 4 And 5 , the beads 3 are located between the seat width reduction 21 and the central zone 23.

In other words, the beads 3 frame the central zone 23 along the transverse median axis MT, and thus frame the dome 5.

With reference to figure 2 And 7 , the beads 3 form, from the outside of the container (1), a concavity in the vault 22. The beads 3 thus have a shape in relief extending inside the volume of the container 1.

• une face avant 31 qui est proximale de la zone centrale 23 ;
• un plateau 32 s'étendant depuis la face avant 31 en direction de l'assise 21 ;
• une face arrière 34 s'étendant depuis le plateau 32 en s'incurvant en direction de l'assise 21, la face arrière 34 étant distale de la zone centrale 23.

With reference to figure 2 , 4 , 5 And 7 , each bead 3 has:

• a front face 31 which is proximal to the central zone 23;
• a plate 32 extending from the front face 31 towards the seat 21;
• a rear face 34 extending from the plate 32 by curving in the direction of the seat 21, the rear face 34 being distal from the central zone 23.

The rear face 34 of each bead 3 joins one of the curved portions 220.

• une distance D, d'une valeur d, le long de l'axe médian transversal MT entre un milieu du plateau 32 de chaque bourrelet 3 et l'axe central C ;
• une distance L, d'une valeur l, entre l'axe central C et chaque extrémité distale de l'assise 21 le long de l'axe médian transversal MT.

With reference to figure 4 And 5 , according to a bottom view, the bottom 12 has:

• a distance D, with a value d, along the transverse median axis MT between the middle of the plate 32 of each bead 3 and the central axis C;
• a distance L, of a value l, between the central axis C and each distal end of the seat 21 along the transverse median axis MT.

In addition, the plate 32 has a length P, of a value p, along the longitudinal median axis ML.

The bead (3), at the level of the front face (31), has a height (H), of a value h.

Each bead 3, depending on the embodiments of the figures 2 to 9 , further has an offset 33 interposed between its plate 32 and its rear face 34. In this case, the rear face 34 extends more precisely from the offset 33.

According to a cross section of each bead 3 illustrated by the figure 7 , the front face 31, the plate 32 and the offset 33 together take on a crenellated shape.

In other words, the front face 31 rises from the arch 22 towards the plate 32, and the offset 33 descends from the plate 32 towards the arch 22.

At the offset (33), the bead (3) has a height (G), of a value g.

• une portion initiale 341 adjacente au plateau ;
• une portion terminale 342 adjacente à l'assise 21.

Still with reference to the figure 7 , for each bead 3 and according to a cross section of the bottom 12, along the median plane, the rear face 34 has:

• an initial portion 341 adjacent to the plate;
• an end portion 342 adjacent to the seat 21.

The initial portion 341 extends parallel to the vault 22, and more specifically to an underlying projection of the vault 22.

A tangent to the end portion 342 has for its part, at its intersection with the seat 21, an angle α, of a value a, with a straight line perpendicular to the transverse median axis MT and inscribed in a median plane of the bottom 12 along a cross section of the bottom 12.

According to the present embodiments, each curved portion 220 has a grainy texture.

These curved portions 220 can nevertheless have a smooth texture.

As mentioned above, the vault 22 has recesses 4.

These recesses 4 delimit, according to a cross section illustrated by the figure 7 , a cavity from the outside of the container 1.

The recesses 4 have a length E, of zero value, along the longitudinal center axis ML.

With reference to the figure 7 , and along the transverse central axis MT, each reduction in width of the seat 21 has a width U, of a value u, and the seat 21 has a residual width O, of a value o.

According to the second embodiment illustrated by the figure 5 , and as mentioned above, the arch 22 comprises branches 6.

Each branch 6 extending along an axis of extension EX from the dome 5 to the seat 21, forming a flattened protrusion projecting into the concavity created by the vault 22 from the outside of the container 1.

According to the present embodiments, each branch 6 also has a central notch 61 creating a concavity in the vault 22, from the outside of the container.

With reference to the figure 5 , for two branches 6 facing each other with respect to the longitudinal central axis ML, and according to a view from below of the bottom 12, the axes of extension EX of these two branches 6 are intersect along the longitudinal median axis ML at a point R. The two points R resulting from the respective intersections of the branches 6 are then spaced apart from each other by a distance Z, by a value z.

In addition, still according to a view from below of the bottom 12, each axis of extension EX intersects the longitudinal median axis ML by forming an angle β (BETA), of a value b.

As mentioned above, the vault 22 includes a dome 5.

This dome 5 has a profile, parallel to the laying plane, which is an oblong shape elongated along the axis ML.

As illustrated by the figures 2 to 7 , the dome 5 creates, from the outside of the container 1, a concavity in the vault 12.

• une longueur X, d'une valeur x, suivant l'axe médian longitudinal ML ;
• une largeur Y, d'une valeur, y, suivant l'axe médian transversal MT.

Dome 5 features:

• a length X, of a value x, along the longitudinal median axis ML;
• a width Y, of a value, y, along the transverse median axis MT.

With reference to the embodiment illustrated by the figures 10 to 12 , the bottom 12 does not include beads 3 or branches 6.

According to this embodiment, the curved portions 220 extend directly from the recesses 4 to the dome 5. Consequently, according to the view illustrated by the figure 11 , each single arcuate section of the curved portion 220 extends from a recess 4 to the dome 5.

• une portion initiale 221 adjacente au dôme 5 ;
• une portion terminale 222 adjacente à l'assise 21.

With reference to the figure 11 , and according to a median cross-section of the bottom 12 passing through the central axis C, each curved portion 220 has:

• an initial portion 221 adjacent to the dome 5;
• an end portion 222 adjacent to the seat 21.

At its junction with the dome 5, the initial portion 221 extends parallel to the transverse median axis MT.

A tangent to the end portion 222 has for its part, at the level of the intersection of said end portion 222 with the seat 21 and similarly to the rear face 34 of the first and second embodiments, an angle α, of a value a, with a straight line perpendicular to the transverse median axis MT and inscribed in a median plane of the bottom 12 according to a cross section of the bottom 12.

• 10% w ≤ de ≤ 30% w, préférentiellement avec de = 20% w ;
• 40% l ≤ d ≤ 65% l, préférentiellement avec d = 50% l ;
• 30% w ≤ y ≤ 40% w ;
• 2,5 y ≤ x ≤ 3,5 y, préférentiellement avec x = 3 y ;
• 30% t ≤ x ≤ 70% t, préférentiellement avec x = 54 % t ;
• 0,7 mm ≤ h ≤ 2.3 mm, et préférentiellement avec h = 1,5 mm ;
• g < h, et préférentiellement avec g = 33% h ;
• 12,5° ≤ a ≤ 22,5°, préférentiellement avec a = 17,5° ;
• 65% t ≤ e ≤ 75% t, préférentiellement avec e = 70% t ;
• 10% (o+u) ≤ u ≤ o, préférentiellement avec u = o ;

The construction rules below are determined with respect to the characteristics of the bottom 12 according to the two embodiments according to the invention illustrated by the figures 2 to 9 :

• 10% w ≤ de ≤ 30% w, preferably with de = 20% w;
• 40% l≤d≤65%l, preferably with d=50%l;
• 30% w ≤ y ≤ 40% w;
• 2.5 y≤x≤3.5 y, preferably with x=3 y;
• 30% t≤x≤70% t, preferably with x=54% t;
• 0.7 mm≤h≤2.3 mm, and preferably with h=1.5 mm;
• g<h, and preferably with g=33% h;
• 12.5°≤a≤22.5°, preferably with a=17.5°;
• 65% t≤e≤75%t, preferably with e=70%t;
• 10% (o+u)≤u≤o, preferably with u=o;

Vis-à-vis the first embodiment illustrated by the figure 4 in which the bottom 12 does not include a branch 6, the following more specific rule applies: 40% t≤p≤65%t, preferably with p=55%t.

Vis-à-vis the second embodiment illustrated by the figure 5 , the following more specific rules apply to the bottom 12: 20% t ≤ p ≤ 40% t, preferably with p = 25% t; 0.12≤z/t≤0.35, and preferably with z/t=0.27; 50°≤b≤63°, preferably with b=57°.

• 10% w ≤ de ≤ 30% w, préférentiellement avec de = 20% w ;
• 2 y ≤ x ≤ 3,5 y, préférentiellement avec x = 2.4 y ;
• 25% t ≤ x ≤ 70% t, préférentiellement avec x = 38 % t ;
• 12,5° ≤ a ≤ 35°, préférentiellement avec a = 26°
• 30% w ≤ y ≤ 45% w

The construction rules below are determined with respect to the characteristics of the bottom 12 according to the third embodiment according to the invention illustrated by the figures 10 to 12 :

• 10% w ≤ de ≤ 30% w, preferably with de = 20% w;
• 2 y ≤ x ≤ 3.5 y, preferably with x = 2.4 y;
• 25% t≤x≤70% t, preferably with x=38% t;
• 12.5° ≤ a ≤ 35°, preferably with a = 26°
• 30% w ≤ y ≤ 45% w

The preceding rules make it possible to obtain a bottom 12 having a continuous seat for a flat container 1, that is to say which comprises a bottom 12 with an oval outline, from a plastic blank and thanks to a manufacturing process by blow molding or stretch-blow molding, without boxing the blank.

As illustrated by the figure 9 , the bottom 12 of the container 1 according to the invention has, thanks to its characteristics, a specific distribution of the plastic material following the blowing of the blank in its transverse distribution. This specific distribution makes it possible to have a similar quantity of plastic material at the level of the seat over the entire periphery of the seat. Indeed, the bottom 12 does not present any accumulation of plastic material at the level of the seat at the level of the short sides of the container 1.

Thus, the quantity of plastic material located in the seat at the transverse level, does not constitute an extra thickness likely to induce imbalances or structural instability of the container compared to the quantity of material located at the longitudinal ends of the seat. .

Claims (19)

1. Container (1) made of plastics material, provided with a body (11) and with a bottom (12) in the continuation of the body (11) at a lower end of the body (11), the bottom (12) having an oblong curved contour and comprising:

   - a seating surface (21) forming a standing plane (210) of the container, the standing plane having an oblong curved shape extending along a longitudinal median axis (ML) and a transverse median axis (MT), the seating surface (21) having a width (W), with a value w, between its distal ends along the transverse median axis (MT);

   - an arch (22) extending from the seating surface (21) as far as a central zone (23) of the bottom (12), the arch (22) delimiting a concavity from the outside of the container (1);

   the container (1) having a central axis (C) on which the central zone (23) is centred,

   characterized in that

   the seating surface (21) has width reductions that are each situated on one side of the longitudinal median axis (ML), at least at the intersection between the seating surface (21) and the transverse median axis (MT),

   and in that

   the arch (22) has, for each width reduction of the seating surface (21), for the one part, an indentation (4) filling said width reduction of the seating surface (21) and forming a concavity from the outside of the container (1), and, for the other part, a curved portion (220) extending directly from said indentation (4) in the direction of the central zone (23), and having, in a section plane passing through the central axis (C) and the transverse axis (MT), a section in the form of a circular arc inscribed in a circle (Cc), the centre of which is situated at a distance (DC), with a value dc, from the central axis (C) along the transverse median axis (MT), with 0.1 w ≤ de ≤ 0.3 w, preferably with de = 0.2 w.
2. Container (1) according to the preceding claim, characterized in that the arch (22) has, between the central zone (23) and a width reduction of the seating surface (21), at least one bulge (3) extending longitudinally and forming, from the outside of the container (1), a concavity in the arch (22).
3. Container (1) according to the preceding claim, characterized in that the bulge (3) has a front face (31) proximal to the central zone (23), a rear face (34) distal from the central zone, and, in between, a flat (32), the rear face (34) being curved in the direction of the seating surface (21), the rear face (34) forming all or part of one of the curved portions (220).
4. Container (1) according to the preceding claim, characterized in that the bulge (3) has, at the front face (31), a height (H), with a value h, with 0.7 mm ≤ h ≤ 2.3 mm, and preferably with h = 1.5 mm.
5. Container (1) according to either one of Claims 3 and 4, characterized in that the bulge (3) has an offset (33) positioned between its flat (32) and its rear face (34), and in that, in a transverse section, the front face (31), the flat (32) and the offset (33) together create a crenelated shape, and in that, at the offset (33), the bulge (3) has a height (G), with a value g, with g < h, and preferably with g = 0.33 h.
6. Container (1) according to any one of Claims 2 to 5, characterized in that the bottom (12) comprises, between the mutually facing bulges (3), and centred on the central zone (23) of the bottom (12), a dome (5), the profile of which, parallel to the standing plane, is an elongate oblong shape along the axis ML and which creates, from the outside of the container (1), a concavity in the arch (12).
7. Container (1) according to Claim 2 and any one of Claims 3 to 6, characterized in that the arch (22) comprises four branches (6) that frame each bulge (3) in pairs, each branch (6) extending along an extension axis (EX) from the dome (5) to the seating surface (21), forming, from the outside of the container (1), a protuberance from the arch (22), and in that, for each bulge (3), the flat (32) has a length (P), with a value p, along the longitudinal median axis (ML), and the seating surface (21) has a length (T), with a value t, between its distal ends along the longitudinal median axis (ML), with 20% t ≤ p ≤ 40% t, preferably with p = 25% t.
8. Container (1) according to the preceding claim, characterized in that, in a view of the bottom (12) from below, each extension axis (EX) of a branch (6) forms, with the transverse median axis (MT), an angle (β), with a value b, with 50° ≤ b ≤ 63°, preferably with b = 57°, and in that the extension axes (EX) of two branches (6) on opposite sides of the longitudinal median axis (ML) cross one another on the longitudinal median axis (ML) at a point (R), the two points (R) being spaced apart from one another by a distance (Z), with a value z, with 0.12 ≤ z/t ≤ 0.35, and preferably with z/t = 0.27.
9. Container (1) according to Claim 2, characterized in that the bottom (12) comprises, between the mutually facing bulges (3), and centred on the central zone (23) of the bottom (12), a dome (5), the profile of which, parallel to the standing plane, is an elongate oblong shape along the axis ML and which creates, from the outside of the container (1), a concavity in the arch (12), each curved portion (220) extending as far as the dome (5).
10. Container (1) according to any one of Claims 6 to 9, characterized in that the dome (5) has: along the longitudinal median axis (ML), a maximum length (X), with a value x; along the transverse median axis (MT), a maximum width (Y), with a value y, with 2 y ≤ x ≤ 3.5 y, preferably with 2.4 y ≤ x ≤ 3 y.
11. Container (1) according to any one of Claims 2 to 10, characterized in that, in a view of the bottom (12) from below, the bottom (12) has: a distance (D) with a value d along the transverse median axis (MT) between the middle of the flat (32) of each bulge (3) and a central point (C) at which the transverse median axis (MT) and the longitudinal median axis (ML) cross one another; a distance (L) with a value 1 between the central point (C) and each distal end of the seating surface (21) along the transverse median axis (MT), with 40% 1 ≤ d ≤ 65% 1, preferably with d = 50% 1.
12. Container (1) according to any one of Claims 2 to 11, characterized in that, for each bulge (3) and in a median transverse section of the bottom (12), the rear face (34) has: an initial portion (341) adjacent to the flat (32), the initial portion (341) extending parallel to the arch (22); a terminal portion (342) adjacent to the seating surface (21), the terminal portion (342) forming, at its intersection with the seating surface (21), an angle, with a value a, with a straight line perpendicular to the transverse median axis (MT) and inscribed in the median transverse section of the bottom (12), with 12.5° ≤ a ≤ 35°, preferably 17.5° ≤ a ≤ 26°.
13. Container (1) according to any one of Claims 2 to 12, characterized in that, for each bulge (3), the flat (32) has a length, with a value p, along the longitudinal median axis (ML), and the seating portion (21) has a length, with a value t, between its distal ends along the longitudinal median axis (ML), with 40% t ≤ p ≤ 65% t, preferably with p = 55% t.
14. Container (1) according to any one of the preceding claims, characterized in that each curved portion (220) has a granular texture.
15. Container (1) according to any one of the preceding claims, characterized in that: each indentation (4) has a length (E), with a value e, along the longitudinal median axis (ML); - the seating surface (21) has a length (T), with a value t, between its distal ends along the longitudinal median axis (ML); with 65% t ≤ e ≤ 75% t, preferably with e = 70% t.
16. Container (1) according to any one of the preceding claims, characterized in that, along the transverse median axis (MT), each width reduction of the seating surface (21) has a width (U), with a value u, the seating surface (21) having a residual width (O), with a value o, with 10% (o+u) ≤ u ≤ o, preferably with u = o.
17. Container (1) according to any one of the preceding claims, characterized in that the seating surface (21) has a width, with a value w, between the distal ends of the seating surface along the transverse median axis (MT), with 30% w ≤ y ≤ 45% w.
18. Container (1) according to any one of the preceding claims, characterized in that the seating surface (21) has a length, with a value t, between its distal ends along the longitudinal median axis (ML), with 25% t ≤ x ≤ 70% t, preferably with x = 54% t.
19. Mould for manufacturing a container (1) by blow-moulding or stretch-blow-moulding a blank made of plastics material, the mould comprising a mould bottom having an upper moulding surface which corresponds to the impression of the bottom (12) of the container (1) according to any one of the preceding claims.

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