Pressurized container with deformable shoulder and bottom

Abstract

The invention relates to a container (1) obtained by blow molding or stretch blow molding from a plastic blank, comprising a body (2), a shoulder (3) continuing the body (2) at the upper end of the body, a neck (4) continuing the shoulder (3), and a bottom (5) at the lower end of the body (2), the shoulder (3) is hinged between at least two stable positions: a deployed position, in which the shoulder (3) protrudes from the main body (2), and a retracted position, in which the shoulder (3) extends flush with the upper end of the main body (2) or at least partially retracts into the main body (2). The bottom (5) is hinged to the lower end of the body (2) between at least two stable positions: an extended position in which the bottom (5) extends flush with the lower end of the body (2) or at least partially protrudes from the body (2), and a retracted position in which the bottom (5) is at least partially retracted into the body (2), so that when the container (1) is filled and closed, the bottom (5) is at least partially retracted into the body (2). Movement of the shoulder (3) from the deployed position to the retracted position causes movement of the bottom (5) from the retracted position to the deployed position, and vice versa. The invention also relates to a mould for producing such a container.

Description

Technical Field

[0001] The present invention relates to a container, more particularly to a potentially stackable PET bottle, which for this purpose comprises a substantially complementary bottom and a neck so as to allow stable stacking of the containers, and to a mould for producing such a container. Background Art

[0002] It is known to produce so-called stackable containers. This is particularly true of US Pat. No. 2,077,027, which describes a stackable container comprising a main body and a frustoconical shoulder attached and secured to the main body by a flange. A stack of containers of this type is naturally stable, but this stability depends to a large extent on the (metal) material from which the containers are made.

[0003] However, this stability is difficult to obtain when the container is obtained by blow moulding (or stretch blow moulding) from a rough blank (especially a preform) made of a plastic material such as polyethylene terephthalate (known as PET). In fact, in addition to the fact that plastic materials have a natural ductility, market demands also tend to produce containers that are lightweight and therefore less rigid.

[0004] In this respect, document EP 0698557 describes such a stackable plastic material container, the bottom of which is shaped to be substantially complementary to the neck to allow stacking. For this reason, the bottom and shoulder of the container are provided with a flat bearing surface on its periphery, the bottom also being provided with a recessed portion for receiving the neck of the following container.

[0005] However, the manufacture of such containers requires a large amount of material in order to make the bottom, which is necessary to give the bottom sufficient rigidity, to give the entire container good mechanical strength and good stability when the containers are stacked. Likewise, a sufficient amount of material is necessary for good blowability of the bottom, i.e. its ability to be correctly formed. On the contrary, an inadequate lightening of the container, especially at the bottom, is detrimental to the mechanical strength of the container and its stacking stability.

[0006] To overcome these drawbacks, there is already a container comprising means capable of generating a positive pressure inside the container and ultimately strengthening the container, in particular in document WO 2007 / 127337.

[0007] Said document WO2007 / 127337 describes a plastic container, said plastic container comprising an upper part, a narrow neck arranged to receive a closure, and a lower part, and a side wall extending between the upper part and the lower part, wherein the upper part comprises a narrow neck arranged to receive a closure, and the lower part comprises a base. The upper part, the lower part and the side wall define an internal volume for storing liquid contents. The plastic container also comprises a pressure panel located on the container and movable between an initial position and an activated position. The pressure panel is located in the initial position before the container is filled, and is positioned in the activated position after the container is filled. The pressure panel moves from the initial position to the activated position, reducing the internal volume of the container and generating a positive pressure inside the container, said positive pressure strengthening the side wall.

[0008] Also known is document EP 2 861 499 of the applicant, which describes a container whose shoulder is articulated between at least a so-called stable extended position and a so-called stable retracted position, in which the internal volume of the container is reduced in order to generate a positive pressure inside the container.

[0009] Document EP2861499 describes a container obtained from a plastic material blank by blow molding or stretch blow molding, the container comprising a main body, a shoulder connected to the main body at the upper end of the main body, and a neck connected to the shoulder, the shoulder being hinged between two stable positions, namely: an extended position in which the shoulder protrudes from the main body and a retracted position in which the shoulder is at least partially retracted into the main body, the shoulder being hinged so that in addition to the extended position and the retracted position, a third stable position between the extended position and the retracted position can also be adopted.

[0010] The stackable retracted position allows the height of the shoulder to be reduced, thereby reducing the receiving volume provided in the bottom. Furthermore, the shoulder is positioned in its retracted position after the container has been filled and plugged, so that the contents of the container are placed under pressure and the rigidity of the container is increased. Thus, the stability of the container stack is increased while reducing the amount of material required to form the bottom.

[0011] It can be seen that it is difficult to achieve a good compromise between the stacking stability and the lightness of plastic material containers. In addition, there is now an increasing need to reduce the weight of containers, not only for economic reasons considering the increasing costs of raw materials, but also for ecological reasons.

[0012] The object of the present invention is therefore to increase the rigidity and stability of a stack of containers whose material content, and thus whose weight, is as low as possible, without adding additional pressurized gas, such as liquid nitrogen, to the interior of the containers. Summary of the invention

[0013] One of the objects of the present invention is therefore to overcome these drawbacks by proposing a container and a mould of simple design and low cost, which require a small amount of material and at the same time provide good rigidity.

[0014] To this end, according to the present invention, a container is proposed which is obtained by blow molding or stretch-blow molding of a rough blank made of plastic material, the container comprising a main body, a shoulder connected to the main body at the upper end of the main body, a neck connected to the shoulder, and a bottom at the lower end of the main body, the shoulder being hinged between at least two stable positions, the two stable positions of the shoulder being: a so-called extended position in which the shoulder extends flush with the upper end of the main body or the shoulder protrudes from the main body, and a so-called retracted position in which the shoulder is at least partially retracted into the main body; the container is characterized in that the bottom is hinged to the lower end of the main body between at least two stable positions, the two stable positions of the bottom being: a so-called extended position in which the bottom extends flush with the lower end of the main body or the bottom protrudes at least partially from the main body, and a so-called retracted position in which the bottom is at least partially retracted into the main body, so that when the container is filled and closed, the shoulder moves from the extended position of the shoulder to the retracted position causing the bottom to move from the retracted position of the bottom to the extended position, and vice versa.

[0015] Preferably, the hinged connection of the shoulder on the body and the hinged connection of the bottom on the body are configured so that when the container is filled and closed, movement of the shoulder from an extended position of the shoulder to a retracted position causes movement of the bottom from a retracted position of the bottom to an extended position while maintaining a pressure level inside the bottle greater than 100 mbar.

[0016] According to a preferred embodiment of the present invention, the shoulder portion comprises a peripheral portion, a central portion and a lower neck portion, the first hinge portion is defined at a junction between the peripheral portion and the central portion, and the second hinge portion is defined at a junction between the central portion and the lower neck portion.

[0017] Additionally, a second hinged portion of the shoulder portion defined at a junction between the central section and the lower neck section is configured to remain locked in the retracted position.

[0018] In addition, the bottom portion includes a peripheral portion and a central portion, a first hinge portion is defined at a junction between the peripheral portion and the central portion, and a second hinge portion is defined at a junction between the peripheral portion and the main body.

[0019] Preferably, the central region of the bottom comprises a concave central dome in the form of a substantially spherical cap with the concave surface facing outwards of the container in the stress-free condition.

[0020] The central dome is rigid or semi-rigid and is not deformable.

[0021] To this end, the central dome may include one or more reinforcements.

[0022] Preferably, the central dome comprises a plurality of radial slots extending from the centre of the central dome to the first hinge portion of the base.

[0023] The body has a generally frustoconical shape with a large base corresponding to the body lower end and a small base corresponding to the body upper end.

[0024] According to one variant embodiment, the body has a square cross section with quarter-circular corners.

[0025] According to another variant embodiment, the body has a substantially cylindrical shape.

[0026] Furthermore, the body is provided with at least one deformable region.

[0027] Advantageously, the body is rigid except for the deformable region.

[0028] Preferably, the body has a superposition of a plurality of annular reinforcements over all or part of its height.

[0029] Another subject of the invention relates to a mould for manufacturing a container according to the invention by blow-moulding or stretch-blow-moulding a blank made of plastic material. The mould comprises at least one mould base which can be mounted movably in a side wall, the side wall defining a cavity for a portion of the container, the side wall comprising two mould halves, each defining a half-cavity for the body of the container and mounted to rotate relative to one another between a so-called open position, in which the two mould halves are angularly separated from one another and the mould base is lowered relative to the two mould halves to allow the introduction of the blank and the removal of the formed container, and a so-called closed position, in which the two mould halves rest against one another and hold the mould base between them so as to thereby form a cavity and define the total cavity for the container to be formed; the mould is characterized in that the half-cavities of the side wall and / or the mould base are shaped for producing a container according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other advantages and features emerge more clearly from the following description of several implementation variants of the container and the mold for producing the container according to the invention, given by way of non-limiting examples, with reference to the accompanying drawings, in which:

[0031] Figure 1 is a perspective view of a container according to the invention shown in the so-called retracted position of the shoulder,

[0032] Figure 2 is a side view of a container according to the invention in the so-called unfolded position at the shoulder,

[0033] Figure 3 is an elevation view of the upper portion of the container in the extended position of the shoulders,

[0034] Figure 4 is an elevation view of the upper portion of the container in the retracted position of the shoulders,

[0035] Figure 5 is an elevation view of the lower portion of the container in a retracted position at the bottom,

[0036] Figure 6is an elevation view of the lower portion of the container in the bottom expanded position,

[0037] Figure 7 is a side view of the upper portion of the container in the deployed position at the shoulders,

[0038] Figure 8 is a side view of the lower portion of the container in the retracted position at the bottom,

[0039] Fig. 9 is an exploded perspective view of a mold for producing a container according to the present invention. DETAILED DESCRIPTION

[0040] In the following of this description of the container according to the invention, the same reference numerals refer to the same elements. The different views are not necessarily drawn to scale.

[0041] The figure shows a container 1 obtained by blow molding or stretch blow molding using a blank made of a plastic material (not shown in the figure). The blank is, for example, a preform, but it can also be an intermediate container that has been subjected to a first blow molding transition operation.

[0042] Reference Figure 1 and Figure 2 , the container 1 comprises a body 2 of generally frustoconical shape extending along a main axis X, said main axis X being vertical, the container 1 being generally shown in an upright position. It will be observed that the body 2 is not necessarily rotationally symmetrical about its main axis X. In fact, the body may have a circular cross section, for example it may be cylindrical, or it may have a square cross section with quarter-circular corners, i.e. with rounded corners, or other shapes without exceeding the scope of the invention.

[0043] The container 1 also comprises a shoulder 3 continuing from the body 2 at its upper end, a neck 4 continuing from the shoulder 3 and a bottom 5 continuing from the body 2 at its lower end. The neck 4 has a hoop 6 near its junction with the shoulder 3, which already exists at the open end of the blank and allows the blank to be suspended during the different manufacturing steps of the container 1. In addition, between the hoop 6 and the shoulder 3, the container 1 has a lower neck area 7, which is cylindrical around the main axis X, so as to provide space sufficient to accommodate a member for gripping the container 1, such as a clamp.

[0044] The shoulder 3 comprises a peripheral zone 8 in the form of a narrower strip of material, i.e. a strip of width between 0.5 mm and 25 mm, the width depending in particular on the dimensions of the container 1, extending from the outer edge and, at the junction between the upper end of the body and the body 2, to an inner edge concentric with the outer edge, defining a first so-called outer articulation 9 of the shoulder 3 relative to the body 2, the inner edge defining a second so-called inner articulation 10 of a central zone 11 of the shoulder 3 relative to the peripheral zone 8. The central zone 11 of the shoulder 3 is generally truncated-conical and extends from the inner articulation 10 of the peripheral zone 8 to the lower neck zone 7.

[0045] The outer hinge 9 and the inner hinge 10 enable the shoulder 3 to adopt two stable positions, namely: Figure 1 and Figure 4 a so-called retracted position shown, in which the shoulder 3 is at least partially retracted into the body 2, the shoulder being retracted along the main axis X towards the bottom 5, the peripheral zone 8 and the central zone 11 both extending obliquely, that is to say their taper pointing in the direction of the neck 4, i.e. upwards and towards the main axis X; and Figure 2 , Figure 3 and Figure 7 The so-called deployed position is shown, in which the shoulder 3 projects from the body 2 , and both the peripheral zone 8 and the central zone 11 extend obliquely, that is to say their taper points in the direction of the neck 4 , ie upwards and towards the main axis X.

[0046] According to an alternative embodiment not shown in the figures, the shoulder 3 could extend flush with the upper end of the body 2 in its so-called unfolded position, ie perpendicularly to the main axis X of the container 1 , without going beyond the scope of the invention.

[0047] It will be observed that the expanded position ( Figure 2 , Figure 3 and Figure 7 ) comes from the forming, that is, the container 1 is formed in this unfolded position. That is, the container 1 is filled and closed in this unfolded position.

[0048] In addition, refer to Figure 5 , Figure 6 and Figure 8 The bottom 5 of the container 1 comprises a peripheral heel 12 in the form of an annular flange, which extends substantially axially in continuation of the body 2. The peripheral heel 12 terminates in a resting plane 13, also called base, perpendicular to the main axis X of the container 1, which defines the lower end of the container 1 and allows the container 1 to rest upright on a flat surface.

[0049] Towards the inside of the container 1, the peripheral heel 12 comprises a frustoconical annular cheek 14 which extends in succession to the abutment plane 13 in the inside of the container 1, the frustocone formed by the annular cheek 14 opening downwards. The bottom 5 further comprises a concave central dome 15 in the form of a substantially spherical cap with the concave side facing outwards of the container 1 in the stress-free state, i.e. in the absence of content in the container 1. The central dome 15 extends in succession to the annular cheek 14 from the peripheral heel 12 to a central region 16 of the bottom 5 which forms a pin-like portion protruding outwards of the container 1 and has in its centre a substantially amorphous tab 17 which corresponds to the injection zone for the injection of the constituent material of the preform for producing the container 1 and which can perform a centering function when the container 1 is molded by blow molding.

[0050] Furthermore, the bottom 5 comprises a peripheral section 18 extending substantially from the peripheral heel 12 to the central dome 15 and a central section 19 substantially corresponding to the central dome 15, a first hinge 20 being defined at the junction between the peripheral section 18 and the central section 19, and a second hinge 21 being defined at the junction between the peripheral section 18 and the body 2 of the container 1. Unlike the inner hinge 10 of the shoulder 3 which is configured to remain locked in the retracted position, the first hinge 20 and the second hinge 21 are not configured to remain locked.

[0051] The movement of the shoulder 3 from the deployed position (the position in which the container is filled and then closed with a stopper) to the retracted position is achieved by rotating the central sector 11 about the inner hinge 10 of the shoulder 3 by exerting downward pressure on the stopper closing the neck 4. The orientation of the peripheral sector 8 remains substantially unchanged, the neck 4 is urged to perform a translation movement downward along the main axis X of the piston, this movement being allowed by the pivoting of the central sector 11 relative to the neck 4 about the outer hinge 9. Moreover, in this particular embodiment, in the retracted position of the shoulder 3, despite the deformation of the bottom 5, the height of the container 1 is less than that of said container 1 when the shoulder 3 is in the deployed position. In this respect, it will be noted that the central dome 15 of the bottom 5 is rigid or semi-rigid and is not deformable. Preferably, said central dome 15 comprises one or more reinforcements (not shown in the figures), for example radial grooves extending substantially from the tab 17 to the first hinge 20.

[0052] When the container 1 is filled, the retraction of the shoulder 3 causes the contents of the container 1 to be pressurized and causes the bottom 5 to move from the retracted position to the deployed position, the movement of the bottom 5 from the retracted position to the deployed position partially compensating for said pressurization. It will be noted that the hinge of the shoulder on the body 2 and the hinge of the bottom 5 on the body 2 are configured so that when the container 1 is filled and closed, the movement of the shoulder 3 from the deployed position to the retracted position causes the bottom 5 to move from the retracted position to the deployed position, while maintaining the bottle internal pressure level greater than 100 mbar. Therefore, the container 1 deforms slightly under the internal pressure, thereby making it possible to stiffen the container, so that the thickness of the container wall can be reduced, thereby making it possible to reduce the material used to manufacture the container, in particular the material required for the bottom 5.

[0053] According to an alternative embodiment not shown in the figures, the bottom 5 can extend flush with the lower end of the body 2 in its so-called unfolded position, so that the annular cheek 14 then forms the base of the container in this unfolded position.

[0054] Optionally, the main body 2 is provided with two annular reinforcement members 22 at its upper part, just below the shoulder 3 , in order to strengthen the main body 2 .

[0055] It goes without saying that, in particular depending on the shape and dimensions of the body 2 of the container, the body 2 may comprise a plurality of annular reinforcements over all or part of its height without going beyond the ambit of the invention.

[0056] According to an alternative embodiment not shown in the figures, the body 2 may be provided with at least one deformable area, for example a deformable panel not shown in the figures, without going beyond the scope of the invention. Moreover, the body is rigid except for the deformable area. In this respect, the body 2 may have a superposition of a plurality of annular reinforcements over all or part of its height.

[0057] refer to Fig. 9 A moulding unit 23 according to the invention is described for forming a container according to the invention, such as a bottle or a can, from a blank, typically a preform.

[0058] refer to Fig. 9The molding unit 23 comprises a mold 24 provided with a side wall 25 defining a cavity 26 of a portion of the container. The mold 24 also comprises a mold bottom 27 having a mold cavity at the bottom of the container, the mold 24 being made of metal, for example steel or aluminum (this term also includes aluminum alloys). The cavity 26, and ultimately the container 1, extends along a main axis X defining a vertical direction. Any plane perpendicular to the main axis X is called a horizontal plane. According to the embodiment shown in the figures, the side wall 25 comprises two half-moulds 24A, 24B, each defining a half-mould cavity 28A, 28B of the container body and mounted to rotate relative to each other about a common axis formed by a hinge (not shown in the figures), between an open position, in which the half-moulds 24A, 24B are angularly separated from each other and the mould base 27 is lowered relative to the half-moulds 24A, 24B to allow the introduction of the blank and the removal of the formed container, and a closed position, in which the half-moulds 24A and 24B abut against each other and hold the mould base 27 between them, so as to thus form the said cavity 26 and define the mould cavity of the container to be formed. The mould base 27 can thus be mounted movably in the mould 24, which comprises two walls that are movable relative to each other and are used to form the container body, the movable mould base 27 pushing the plastic material constituting the container towards its opening. The half-mould cavities 28A, 28B and / or the mould base 27 of the side wall 25 are shaped for producing a container 1 according to the invention as described above.

[0059] Finally, it is quite clear that the examples that have just been given are only specific illustrations and do not in any way limit the field of application of the invention.

Claims

1. A container (1) obtained by blow moulding or stretch-blow moulding of a rough blank made of plastic material, the container comprising a body (2), a shoulder (3) connected to the body (2) at the upper end of the body, a neck (4) connected to the shoulder (3) and a bottom (5) at the lower end of the body (2), the shoulder (3) being hinged between at least two stable positions, the two stable positions of the shoulder being: an extended position in which the shoulder (3) protrudes from the body (2) and a retracted position in which the shoulder (3) extends flush with the upper end of the body (2) or is at least partially retracted into the body (2), characterized in that The bottom (5) is hinged to the lower end of the body (2) between at least two stable positions, namely: an extended position in which the bottom (5) extends flush with the lower end of the body (2) or the bottom at least partially protrudes from the body (2), and a retracted position in which the bottom (5) is at least partially retracted into the body (2), so that when the container (1) is filled and closed, the shoulder (3) moves from the extended position of the shoulder to the retracted position of the shoulder, causing the bottom (5) to move from the retracted position of the bottom to the extended position of the bottom, and vice versa.

2. The container (1) according to claim 1, characterized in that The hinges (9, 10) of the shoulder (3) on the body (2) and the hinges (20, 21) of the bottom (5) on the body (2) are configured so that when the container (1) is filled and closed, the movement of the shoulder (3) from the extended position of the shoulder to the retracted position of the shoulder causes the bottom (5) to move from the retracted position of the bottom to the extended position of the bottom, while maintaining a pressure level inside the container (1) greater than 100 mbar.

3. The container (1) according to claim 1 or 2, characterized in that: The shoulder portion (3) comprises a peripheral region (8), a central region (11) and a lower neck region (7), a first external hinge portion (9) being defined at a junction between the peripheral region (8) and the central region (11), and a second internal hinge portion (10) being defined at a junction between the central region (11) and the lower neck region (7).

4. The container (1) according to claim 3, characterized in that A second inner hinged portion (10) of the shoulder portion (3) defined at the junction between the central portion (11) and the lower neck portion (7) is configured to remain locked in the retracted position.

5. The container (1) according to any one of claims 1 to 4, characterized in that The bottom (5) comprises a peripheral area (18) and a central area (19), the first hinged portion (20) is defined at a junction between the peripheral area (18) of the bottom and the central area (19) of the bottom, and the second hinged portion (21) is defined at a junction between the peripheral area (18) of the bottom and the main body (2).

6. The container (1) according to claim 5, characterized in that The central region (19) of the bottom (5) comprises a concave central dome (15) in the form of a substantially spherical cap with the concave side facing outwardly of the container (1) in the stress-free state.

7. The container (1) according to claim 6, characterized in that The central dome (15) is rigid or semi-rigid.

8. The container (1) according to claim 7, characterized in that The central dome (15) includes one or more reinforcement members.

9. The container (1) according to claim 8, characterized in that The central dome (15) comprises a plurality of radial slots extending from the centre of the central dome (15) to the first hinge (20) of the base (5).

10. The container (1) according to any one of the preceding claims, characterized in that The main body (2) has a generally truncated cone shape, with a large base corresponding to the lower end of the main body (2) and a small base corresponding to the upper end of the main body (2).

11. The container (1) according to any one of claims 1 to 10, characterized in that The main body (2) has a square cross-section with quarter-circular corners.

12. The container (1) according to any one of claims 1 to 10, characterized in that The body (2) has a generally circular cross-section.

13. Container (1) according to any one of the preceding claims, characterized in that The main body (2) is provided with at least one deformable area.

14. The container (1) according to claim 13, characterized in that Apart from the deformable region, the body (2) is rigid.

15. The container (1) according to claim 14, characterized in that The main body (2) has a plurality of annular reinforcements (22) stacked over the entire or partial height thereof.

16. A mould (24) for manufacturing a container (1) by blow moulding or stretch-blow moulding of a blank made of plastic material, the mould (24) comprising at least one mould bottom (27) which can be movably mounted in a side wall (25), the side wall defining a cavity (26) for a portion of the container (1), the side wall comprising two mould halves (24A, 24B), each defining a half-cavity (28A, 28B) of the body (2) of the container (1) and being mounted to rotate relative to each other between an open position and a closed position, in which the two mould halves (24A, 24B) are angularly separated from each other and the mould bottom (27) is lowered relative to the two mould halves (24A, 24B) to allow the introduction of the blank and the removal of the formed container (1), and in the closed position, the two mould halves (24A, 24B) abut against each other and hold the mould bottom (27) between the two mould halves so as to thereby form the cavity (26) and define the total cavity of the container (1) to be formed, characterised in that The mold half-cavities (28A, 28B) of the side wall and / or the mold bottom (27) are shaped for producing a container (1) according to any one of claims 1 to 15.

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