WO2013088006A1 - Stackable container comprising an arched base having a wide area of contact - Google Patents

Abstract

The invention relates to a stackable container (1) provided with a body (2) and a base (3) comprising: an annular seat (10) defining a positioning plane (11) complementary to a peripheral surface (8) provided on a shoulder (4); a conical arch (14) which extends away from the seat (10). In this container: an external transverse extension Dext of the seat and a transverse extension D outside the entire body are such that: Dext/D≥0.8, the arch (14) has a peripheral section (17) complementary to a frustoconical bearing surface (7) of the shoulder (4), the positioning plane (11) and the peripheral supporting section (17) define an area of contact, the projection of which on the positioning plane (11) has a surface area Sc such that: Sc/S≥0.4, where S is the surface area of the area delimited by an outside perimeter (12) of the seat (10).

Description

 Stackable container having a large contact area with a vaulted bottom

The invention relates to containers, and more particularly to containers stackable, that is to say shaped to be stacked on each other and provided for this purpose with a substantially complementary bottom and neck that the neck of an underlying container can be inserted into the bottom of a higher identical container.

 Stackable containers are useful in many applications where the containers are not grouped in small numbers (eg 6 to 8 containers for home use) and packaged in shrink wrap packs, but stacked directly on top of one another for palletized, the pallet once filled can then be packaged under stretch film.

 It is understood that it is necessary to best stabilize the containers to prevent collapse of the batteries before the final packaging. The safety of the staff involved and the integrity of the containers are at stake.

 US Pat. No. 7,699,171 (Consolidated Container) is known from

Company) a substantially cubic shaped can with a capacity of between one pint (about 0.5 I) and 5 gallons (about 19 I), and preferably 1 gallon (about 3.8 I), the bottom of which defines a conical stack reserve defining a perimeter corresponding to the perimeter of a shoulder portion of a can of identical structure.

 The stacking method consists in manually grouping the containers in pairs, packing each shrinkwrap pair and then positioning the pairs thus formed on a pallet. Once a first layer of containers has been formed, a second layer of paired, film-wrapped containers is stacked on the first layer, nesting the second layer containers on top of those of the first layer.

It is indicated that a "lock" is made between an upper container and an identical lower container, and more precisely between a recessed portion of the bottom of the upper container and the shoulder portion of the lower identical container. This "locking" does not appear clearly defined, but it can however be understood that it is made locally, on the upper container at a hollow reserve formed in (or adjacent to) the stacking reserve, and on the lower container at a lip formed at the periphery of the shoulder portion.

 The containers described in this document, and their stacking technique - related to the shape of the containers - have several disadvantages.

 First, the distribution of efforts is insufficient. More specifically, the surfaces in contact between the upper container and the lower identical container (ensuring the recovery of the forces due to the weight of the upper container and the possible containers that rest on it in the stack) are located near areas undergoing damage. abrupt variations in curvature (typically a lip formed at the periphery of the shoulder portion), likely to constitute rupture primers.

 Secondly, because of the shape and size of the zones (on the bottom and on the shoulder) intended to cooperate, the proposed locking interlock does not in itself have sufficient rigidity to allow free stacking of the containers. It is understood that it is to compensate for this lack of natural stiffness of the stack that it is recommended to group and put the containers in pairs film.

 Thirdly, grouping and pairwise setting of containers, which can be justified for the palletization of large capacity cans (typically the 5 gallon containers referred to in the aforementioned patent), is not realistic for capacity containers. medium or low (typically a pint), whose modern production rates, up to 50,000 containers per hour, are impossible to meet by the operators responsible for training and filming pairs and their palletization.

Fourthly, the centering of an upper container with respect to a lower container, essential for the "locking" recommended, requires precise positioning of the containers during stacking, except to admit a guide of the containers by sliding the neck of the lower container against the conical stacking reserve of the upper container. Such guidance, shock generator, is likely damaging the tapered stack and / or peelable seal closing the neck of the lower container.

 Fifth, if it is stated in substance that the container can be of low capacity (1 quart), it is difficult to see how to adapt the shape of the bottom to such a container, with a wide neck (that is to say, whose neck is relatively wide compared to the body of the container), thus reducing the space available at the shoulder.

 Also known from EP 0 698 557 are stackable containers of rectangular section, designed to locate the repeated stacking efforts in the corners of the upper rectangular portions of the containers. In contrast, the containers are dimensioned so that there remains a space between their inclined surfaces, and that they are not in contact.

 This technique has a major disadvantage: the recommended space between the conical surfaces, necessary for locating the forces on the flat peripheral parts of the containers, induces a lateral play of positioning of the containers during stacking. This game, accumulated on a stack of three (or more) containers makes the pile naturally unstable and therefore likely to overturn.

 A first objective is therefore to provide a stackable container whose structure gives the stack a good structural rigidity in the absence of any packaging, particularly to allow a palletization without risk.

 A second objective is to provide a stackable container whose positioning on an identical underlying container is simple and easy.

 A third objective is to provide a stackable container whose compressive strength due to stacking is high.

 A fourth objective is to provide a stackable container ensuring a good distribution of the forces due to the stack.

 A fifth objective is to provide a container with a large neck easily stackable.

 A sixth objective is to propose a stackable container meeting at least one of the aforementioned objectives while having a good blowing.

For this purpose, it is proposed a stackable plastic container, comprising a body extending along a main axis and having an overall transverse D-extension, a shoulder extending from the body to an upper side, a neck extending from the shoulder, and a bottom extending from the body to a lower side, the shoulder comprising, under the neck, a frustoconical bearing surface and, at its junction with the body, a peripheral face defining a bearing plane substantially perpendicular to the main axis, this peripheral bearing face being separated from the frustoconical bearing surface by an axial recess, the background comprising:

 an annular base defining a laying plane complementary to the peripheral bearing face and having an external transverse extension XD;

 a conical vault that extends from the seat to a central area.

In this container:

the external transverse extension Dext of the seat and the transverse extension D transversal of the whole body are such that:

^J ext

 ≥ 0.8

 D

the arch has a peripheral support section complementary to the frustoconical scope of the shoulder, which extends between the seat and a central pin adapted to encompass the neck of an underlying container, - the laying plane and the peripheral support section of the vault defines a contact surface whose projection on the laying plane has an area Se such that:

 where S is the area of the area bounded by an outer perimeter of the seat.

 Tests have shown that such a design makes it possible, together, to obtain a good coaxiality of the stacked containers, to the benefit of the stability of the stack, to properly distribute the load transmitted by the upper containers to the lower containers, while ensuring good flowability, necessary for production on an industrial scale.

The following additional features may be provided individually or in combination: the shoulder comprises an axial recess separating the peripheral bearing surface from the frustoconical bearing surface, and the bottom comprises an axial inner annular cheek complementary to the recess.

a height H of the cheek and a width L of the laying plane are such that:

 0.5 <^ <2

 the ratio between an internal transverse extension Dint and an external transverse extension Dext of the seat is such that:

 Dint

 0.7 <<0.95

 Dext

 the frustoconical bearing has an angular opening of between 5 ° and 40 °;

 the L / H ratio is about 0.65;

 the Sc / S ratio is about 0.55;

 the frustoconical bearing is provided with stiffeners;

 the bottom is provided with a central pin provided with stiffeners;

- The pin has an inner diameter Dp whose ratio to the overall transverse dimension D of the body is greater than or equal to 0.4.

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

 Figure 1 is a side view showing a plastic container, according to a first embodiment;

 Figure 2 is a perspective view from below of the container of Figure 1;

- Figure 3 is a perspective view, on an enlarged scale, showing the bottom of the container according to detail III of Figure 2;

 Figure 4 is a view similar to Figure 2, showing a container according to a second embodiment;

 Figure 5 is a perspective view, on an enlarged scale, showing the bottom of the container according to detail V of Figure 4;

Figure 6 is a detail sectional view of the container of one or other of the embodiments of Figures 2 or 4, shown on a flat surface; Figure 7 is a partial sectional view, in detail, of two identical containers stacked, according to one or the other embodiment of Figures 2 or 4.

 In FIGS. 1 to 3, on the one hand, 4 and 5, on the other hand, two exemplary embodiments of a container 1 formed by stretch-blow molding from a thermoplastic preform such as PET (polyethylene terephthalate) are shown. ). This container 1, especially a bottle, is typically of a capacity of 2 I but this capacity could, without modification of the proportions of the container 1, be reduced, for example up to 0.1 I or increased to 20 I.

 The container 1 comprises a cylindrical body 2 (which may be of square section, as in the embodiment of FIG. 1, or circular, as in the embodiment of FIG. 3), which extends along an axis Main X

 The body 2 is extended, on a lower side, by a bottom 3, and, from an upper side opposite the bottom 3, by a shoulder 4 itself extended by a neck 5 defining a rim. The neck 5 is arranged, for example threaded, to allow the removable attachment of a plug 6.

 The body 2 has a transverse extension (that is to say measured in a plane perpendicular to the main axis X) all noted D. (D is the measurement of the outer diameter of the body 2 when the container 1 is symmetrical with revolution as in the example shown in Figures 4 and 5, or the measurement of a side of the body 2 in section when it is square section).

 In the example shown, the container 1 is wide-necked, that is to say that the diameter of the neck 5, denoted by De, is greater than one-third of the overall extension D of the body 2.

 The shoulder 4 forms a transition between the neck 5 and the body 2. The shoulder 4 comprises, under the neck 5, a frustoconical bearing surface 7 whose opening angle, denoted by A, measured with respect to a plane perpendicular to the axis of the container is between 5 ° and 40 °, and preferably about 25 °.

As illustrated in FIG. 6, the frustoconical bearing surface 7 is not contiguous with the body 2, the shoulder 4 comprising an annular peripheral bearing face 8 which defines a perpendicular (or substantially perpendicular) bearing plane to the main X axis and has a width L, measured transversely. This bearing peripheral face 8 is separated from the frustoconical bearing surface 7 by a recess 9 which extends axially, that is to say substantially parallel to the main axis X of the container 1, or preferably, as in FIG. example shown in Figure 6, forms a slight draft having a closed apex angle. This apex angle is for example between about 15 ° and 45 ° (typically, this apex angle is about 20 °). We denote by H the height, measured axially, of the recess 9.

 As can be seen in FIG. 6, the bottom 3 is shaped to accommodate the upper part (shoulder 4 and neck 5) of an identical underlying container 1, so as to allow the containers 1 to be stacked.

 More specifically, the bottom 3 is partially conformed in a manner complementary to the shoulder 4, so as to allow stacking by simple insertion of the shoulder 4 of the underlying container 1 into the bottom 3 of the upper container.

 Thus, the bottom 3 comprises, firstly, an annular seat 10 which defines a continuous laying plane 11, complementary to the peripheral support surface 8 of the shoulder 4 and extends in a plane perpendicular to the axis Main X We notice :

 S the area of the area delimited by an outer perimeter 12 of the seat 10 (at a junction between the laying plane 11 and the body 2), that is to say the area of the overall area of the bottom 3, projected in the plane of the bearing face 8 (parallel to the axis X of the container 1), and

 Dext the external transverse extension of the seat 10, measured at the outer perimeter 12 thereof (Dext is the measurement of the outer diameter of the seat 10 when the container 1 is symmetrical of revolution as in the illustrated example in Figures 4 and 5),

The annular seat 10 also defines an axial inner annular cheek 13 complementary to the recess 9, which extends axially from the laying plane 11 towards the inside of the container 1. The cheek 13 extends substantially parallel to the main X axis (when the recess 9 extends substantially parallel to the main axis X), or preferably form, as shown in Figures 6 and 7, a slight clearance substantially identical to the remains of the recess 9, allowing easy introduction of a container 1 relative to the other.

 Dint the internal transverse extension of the seat 10, measured at the cheek 13.

 It will be noted that Dext and Dint are the respective measurements of the inside diameter and the outside diameter of the seat 10 when the container 1 is symmetrical with revolution as in the example illustrated in FIGS. 4 and 5.

 The bottom 3 comprises, secondly, a conical vault 14 extending from the seat 10 - and more precisely from an edge

15 inside the recess 9 - towards a central zone of the bottom 3.

 As seen in Figures 6 and 7, the vault 14 is in two parts, and comprises:

 a central pin 16, a side wall of which extends substantially axially with, preferably, a slight taper (with a relief angle, denoted B, of between 10 ° and 20 °, and preferably of approximately 15 °), this pin 16 being shaped and dimensioned to completely encompass the neck 5 of the underlying container 1, a peripheral support section 17 complementary to the frustoconical bearing surface 7 of the shoulder 4 of the underlying container 1, this peripheral section 17 extending between an upper edge of the cheek 13 and a lower edge 18 (in the rounded case) of the central pin 16, whose transverse extension Dp is noted, measured perpendicularly to the axis X of the container 1 (Dp is a diameter, in the case of a cylindrical vessel 1 of revolution as illustrated in the example of Figures 4 and 5).

 The peripheral section 17 accordingly has the same opening angle A as the frustoconical bearing surface 7 (between 5 ° and 40 °, and preferably about 25 °).

 The laying plane 11 has a width, measured perpendicularly to the axis X, substantially equal to width L of the bearing face 8.

For a container 1 wide neck 5 as shown, the central pin 16 has, given the clearance required for insertion, an inner diameter Dp whose ratio to the overall transverse dimension D of the body 2 is greater than or equal to 0 , 4, and for example about 0.5: dp

 ≥0,4

 and for example:

 dp

≡ ⁰ ' ⁵

 When, as shown in Figure 7, the container 1 is stacked on an underlying container 1, the shoulder 4 of the underlying container 1 being inserted into the bottom 3 of the upper container 1: the plane 11 laying the upper container 1 is applied against the peripheral face 8 support of the underlying container 1;

 the recess 9 of the underlying container 1 is inserted into the cheek 13 of the upper container 1;

 the peripheral section 17 of the vault of the upper container 1 is pressed against the frustoconical bearing surface 7 of the underlying container 1.

 The laying plane 11, the cheek 13 and the peripheral section 17 of the vault 14 together define a contact surface with the shoulder 4 of the underlying container 1. Note Se the area of the projection of this contact surface on the plane of the peripheral surface 8 of support of the underlying container (that is to say, on the laying plane 11).

 The flange 13 also extends axially over a height substantially equal to the height H of the recess 9.

 The bottom 3 is dimensioned as follows:

 the ratio between the external transverse Dext extension of the seat and the overall transverse extension of the body is greater than 0.7, and preferably greater than 0.8:

 Dext

 ≥ 0.8

 D

and preferably

 Dext

 > 0.85

 D

 preferably, the ratio of the height H of the flange 13 and the width L of the laying plane 11 is between 0.5 and 2 (and preferably about 0.55):

 0.5 <^ <2

the ratio between the surface area Se of the bearing surface formed by the laying plane 11, the cheek 13 and the peripheral section 17 of a on the other hand, and the area S of the area delimited by the outer perimeter 12 of the seat 10 on the other hand, is greater than 0.4, and preferably greater than 0.5 and less than 0.65:

 himself

y _≥ 0.4

and preferably:

 himself

 0.5≤-≤ 0.65

 In other words represents the area of the flat surface delimited externally by the outer perimeter 12 of the seat 10, of transverse dimension Dext, and internally by the projection in the laying plane 11 of the lower edge of the peg, of dimension transversal Dp.

 It follows from the architecture which has just been described a better structural rigidity of the stack of the containers 1 thus designed and a better distribution of the compressive forces exerted on an underlying container, in particular because:

 the importance of the bearing surface (also called interface) between the two containers 1 superimposed, which maximizes friction and increases the strength of the stack;

 of the offset of the seat 10 (and thus of the bearing surface 8) towards the periphery of the container 1 (resulting from the value of the ratio close to 1)

- The perpendicularity of the laying plane 11 relative to the axis X of the container and the square character of the seat 10 (resulting from the value of the ratio - close to 1), these two factors limiting the risk of tilting of a container 1 with respect to the underlying container 1;

- The importance of the contact surface between the peripheral section 17 of the vault 14 and the frustoconical surface 7 of the underlying container 1, which makes it possible to achieve easier and faster centering of the containers 1 during their stacking.

 According to a particular embodiment, - is equal to about 0.65,

 H

 Se Dcxt

y equal to about 0.55, and - ^ - equal to about 0.85, which constitutes a good compromise between the structural rigidity of the container (which is wish to maximize) and its blowing (which one also wishes to maximize but which may turn out to vary inversely with the rigidity).

 It is also preferable to maintain the ratio between the internal transverse extension Dint and the external transversal extension Dext of the seat 10 between 0.7 and 0.95:

 Dint

 0.7≤ <0.95

 Dext

 This results in a small width L of the laying plane (relative to the overall transverse extension of the bottom 3), which promotes the intrinsic stability of the container 1, it rests on a flat surface (shown in dashed lines on the Figure 6) or on an underlying container 1 on which it is stacked (as in the example of Figure 7).

 In addition, it may be preferable to provide the frustoconical bearing surface 7, as illustrated in FIG. 7, with stiffeners 19 in the form of ribs or radial grooves, for example regularly in the form of a star around the circumference of the frustoconical bearing surface 7. These stiffeners 19 increase the structural rigidity of the frustoconical bearing surface 7 and limit the collapse of the latter during the stacking of the containers 1.

 Similarly, as illustrated in Figures 3 and 5, the central pin 16 is also provided with stiffeners 20 in the form of ribs or radial grooves, distributed in a star on the circumference of the pin 16, from a center. These stiffeners 20 give the pin 16 a good performance and particularly avoid its misalignment during stacking containers 1, which would have adverse consequences on the proper alignment of such containers during stacking.

Claims

1. Container (1) stackable plastic, comprising a body (2) extending along a main axis (X) and having an overall transverse extension D, a shoulder (4) in the extension of the body (2) on an upper side, a neck (5) in the extension of the shoulder (4), and a bottom (3) in the extension of the body (2) on a lower side, the shoulder (4) ) comprising, under the neck (5), a frustoconical bearing surface (7) and, at its junction with the body (2), a peripheral face (8) defining a bearing plane substantially perpendicular to the main axis (X) , the bottom (3) comprising:  an annular seat (10) defining a complementary laying plane (11) of the peripheral bearing face (8) and having an external transverse extension Ext; - a conical arch (14) extending from the seat (10) to a central area; characterized in that  the external transverse Dext extension of the seat and the transverse extension D in the whole of the body are such that:  Dext  -> 0.8 the vault (14) has a peripheral section (17) of complementary support of the frustoconical bearing surface (7), which extends between the seat (10) and a central pin (16) capable of encompassing the neck (5); ) an underlying container (1),  the laying plane (11) and the peripheral support section (17) of the vault (14) define a contact surface whose projection on the laying plane (11) has an area Se such that:  himself y _≥ 0.4  where S is the area of the area bounded by an outer perimeter (12) of the seat (10). 2. Container (1) according to claim 1, characterized in that the shoulder (4) comprises a recess (9) axially separating the face (8) bearing device of the frustoconical bearing surface (7), and the bottom ( 3) comprises an axial inner annular cheek (13) complementary to the recess (9). 3. Container (1) according to claim 2, characterized in that a height H of the cheek (13) and a width L of the laying plane (11) are such that:  0.5 <^ <2  4. Container (1) according to one of the preceding claims, characterized in that the ratio between an internal transverse extension Dint and an external transverse extension Dext of the seat is such that:  Dint  0.7≤ <0.95  Dext  5. Container (1) according to one of the preceding claims, characterized in that the frustoconical surface (7) has an angular opening (A) between 5 ° and 40 °.  6. Container (1) according to one of the preceding claims, characterized in that the L / H ratio is about 0.65.  Container (1) according to one of the preceding claims, characterized in that the Sc / S ratio is about 0.55.  8. Container (1) according to one of the preceding claims, characterized in that the frustoconical bearing surface (7) is provided with stiffeners (19).  9. Container (1) according to one of the preceding claims, characterized in that the bottom (3) is provided with a pin (16) provided with central stiffeners (20).  Container (1) according to one of the preceding claims, characterized in that the pin (16) has an inner diameter Dp whose ratio to the overall transverse dimension D of the body (2) is greater than or equal to 0, 4.