Container comprising a bottom provided with a varying arch

Abstract

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

Claims

1. Container (1) made of plastic material, comprising a body (2) with a polygonal cross-section that extends along a main axis (X), a shoulder (4) that forms an extension of the body (2) of an upper side, a neck (5) that forms an extension of the shoulder (4), and a bottom (3) that forms an extension of the body (2) of a lower side, with said bottom (3) comprising: an annular seat (9) that defines a placement perimeter (10), with a polygonal contour formed by a number of sides and vertices, essentially perpendicular to the main axis (X); a central peg (16) that has a side wall (17) that is tapered overall in revolution around the main axis (X) and that is connected to the rest of the bottom (3) by a connecting fillet (19), wherein the connecting fillet (19) has a variable radius (R) in revolution around the main axis (X) of the container (1), this radius (R) having a minimum value (Rm) in any sector (S1) delimited by a vertex (12) of the placement perimeter (10), and a maximum value (RM) in any sector (S2) delimited by a side (11) of the placement perimeter (10).

2. Container according to claim 1, wherein the radius (R) of the connecting fillet (19) has its maximum value (RM) in any bisecting plane at a side (11) of the placement perimeter.

3. Container according to claim 1, wherein the radius (R) of the connecting fillet (19) has its minimum value (Rm) in any bisecting plane at a vertex (12) of the placement perimeter (10).

4. Container according to claim 1, wherein the radius (R) of the connecting fillet (19) is continuously variable between its minimum value (Rm) and its maximum value (RM).

5. Container according to claim 1, wherein the maximum value (RM) and the minimum value (Rm) of the radius (R) of the connecting fillet are in a ratio of between 2 and 3.

6. Container according to claim 1, wherein the maximum value (RM) and the minimum value (Rm) of the radius (R) of the connecting fillet are in a ratio of approximately 2.5.

7. Container according to claim 1, wherein the placement perimeter (10) has a square contour that comprises four sides (11) and four vertices (12).

8. Container according to claim 7, wherein the radius (R) of the connecting fillet (19) has four maximum values (RM) facing the sides (11) and four minimum values (Rm) facing the vertices (12).

9. Container according to claim 1, wherein the radius (R) of the connecting fillet (19) has sinusoidal variations in revolution around the main axis (X).

10. Container according to claim 1, wherein under the neck (5), the shoulder (4) comprises a tapered area (7) and, at its junction with the body (2), a peripheral support face (8), with a polygonal contour, complementary to the placement perimeter (10) defined by the annular seat (9), essentially perpendicular to the main axis (X).

11. Container according to claim 2, wherein the radius (R) of the connecting fillet (19) has its minimum value (Rm) in any bisecting plane at a vertex (12) of the placement perimeter (10).

12. Container according to claim 2, wherein the radius (R) of the connecting fillet (19) is continuously variable between its minimum value (Rm) and its maximum value (RM).

13. Container according to claim 2, wherein the maximum value (RM) and the minimum value (Rm) of the radius (R) of the connecting fillet are in a ratio of between 2 and 3.

14. Container according to claim 2, wherein the maximum value (RM) and the minimum value (Rm) of the radius (R) of the connecting fillet are in a ratio of approximately 2.5.

15. Container according to claim 2, wherein the placement perimeter (10) has a square contour that comprises four sides (11) and four vertices (12).

16. Container according to claim 2, wherein the radius (R) of the connecting fillet (19) has sinusoidal variations in revolution around the main axis (X).

17. Container according to claim 2, wherein under the neck (5), the shoulder (4) comprises a tapered area (7) and, at its junction with the body (2), a peripheral support face (8), with a polygonal contour, complementary to the placement perimeter (10) defined by the annular seat (9), essentially perpendicular to the main axis (X).

Description

(1) Other objects and advantages will be brought out in the description of embodiments, provided below with reference to the accompanying drawings, in which:

(2) FIG. 1 is a perspective bottom view, showing, in a realistic manner, a container with a polygonal cross-section;

(3) FIG. 2 is a realistic detail view showing, on an enlarged scale, the bottom of the container of FIG. 1; for better understanding of the shapes of the bottom, certain lines marking the curvature of the surfaces of the latter were plotted; in addition, for creating the placement perimeter, the latter was filled with a honeycomb pattern, and for creating the connecting fillet of the central peg, the latter was filled with a dot pattern;

(4) FIG. 3 is a realistic bottom plan view of the bottom of FIG. 2, on which the placement perimeter and the connecting fillet of the central peg are also filled, respectively with a honeycomb pattern or with a dot pattern;

(5) FIG. 4 is a flattened cutaway view of the bottom of FIG. 3, along the broken cutting line IV-IV, which furthermore shows the shoulder of a container on which the bottom of FIG. 3 would be stacked;

(6) FIGS. 5 and 6 are detail views of the bottom, on an enlarged scale, along the rectangular inserts V and VI plotted in FIG. 4;

(7) FIG. 7 is a diagram that illustrates the variations of the radius of the connecting fillet of the peg with the rest of the bottom, based on the angle between the measuring half-plane and a reference half-plane centered on a side of the placement perimeter, in a complete revolution around the axis of the container.

(8) FIG. 1 shows a container 1 formed by blow molding or stretch blow molding starting from a preform made of thermoplastic material such as PET (polyethylene terephthalate). This container 1, in this case a bottle, typically has a 0.5 l capacity, but this capacity is not limiting and could be greater, for example 1.5 l.

(9) The container 1 comprises a body 2 that extends along a main axis X. The body 2 has a polygonal cross-section (i.e., perpendicularly to the main axis X). In this application, the terms polygon and polygonal have a wide acceptance and are not limited to the strict mathematical definition of a closed geometry that consists of straight segments (forming the sides of the polygon), contiguous by their ends (forming the specific vertices of the polygon), but rather cover close geometries in which the sides can be curves (for example, in the shape of arcs) and rounded vertices. According to this definition of the polygon, the cross-section of the container that is illustrated in the figures (cf. in particular FIG. 3) can be described as square.

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

(11) The body 2 is extended, from a lower side, by a bottom 3, and, from an upper side opposite to the bottom 3, by a shoulder 4 that is itself extended by a neck 5 that defines a lip. The neck 5 is arranged (for example threaded) to make possible the removable attachment of a stopper 6.

(12) The shoulder 4 forms a transition between the neck 5 and the body 2. Under the neck 5, the shoulder 4 comprises a tapered area 7. As illustrated in FIG. 4, the tapered area 7 is not directly contiguous with the body 2, with the shoulder 4 comprising a peripheral face 8 that, in the case of a stackable container, is a support face with a polygonal contour (in the general meaning indicated above) that is similar to that of the cross-section of the body 2. In this case, this contour is therefore square.

(13) This peripheral support face 8 extends essentially in a transverse plane from an upper end of the body 2 to an inside edge that forms a junction with the tapered area 7. According to a preferred embodiment, illustrated in FIG. 4, the peripheral support face 8 is not completely flat but rather forms a slight taper (by an angle of several degrees).

(14) As can be seen in FIG. 4, the bottom 3 can be shaped to accommodate the upper portion (shoulder 4 and neck 5) of an identical underlying container 1in such a way as to make possible the stacking of the containers 1. More specifically, the bottom 3 is partially shaped in a manner complementary to the shoulder 4, in such a way as to make possible the stacking by simple insertion of the shoulder 4 of the underlying container 1 into the bottom 3 of the upper container 1.

(15) Thus, in such a case of a stackable container, the bottom 3 comprises, in the first place, an annular seat 9 that forms an extension of the body 2 and defines a placement perimeter 10 that is complementary to the peripheral support face 8 of the shoulder 4.

(16) The placement perimeter 10 is a strip of material of small width in relation to the overall transverse extension of the bottom 3. To facilitate engagement on the peripheral support face 8 of the underlying container 1, the placement perimeter 10 is not completely flat but rather has, in relation to a transverse plane, a slight reverse taper, as illustrated in FIG. 4.

(17) As illustrated in FIGS. 2 and 3, applicable to containers that may or may not be stackable, the placement perimeter 10 has a polygonal contour that is similar to that of the container 1. In this case, this contour is square (in the meaning indicated above). The placement perimeter 10 comprises a number of sides 11, straight or curved (as in the illustrated example), as well as top zones (more simply called vertices below) 12 where the sides join. As FIGS. 2 and 3 clearly show, where the placement perimeter 10 is created with a honeycomb pattern, the vertices 12 are rounded (it is therefore understood that they are not points but rather have a certain arc length).

(18) More specifically, the sides 11 of the placement perimeter 10 are created with a relatively loose honeycomb pattern, and the vertices 12 are created with a denser honeycomb pattern. The junction lines between the sides 11 and the vertices 12 are provided by way of indication and are not visible on the physical container.

(19) In the illustrated example, where the placement perimeter 10 is regular (in this case, a square), this perimeter 10 is invariant by rotation around the main axis X by an angle of

(20) $\frac{2}{N},$
where N is the number of sides (or vertices) of the polygon. Consequently, the geometric properties of each side 11 can be transposed to the other sides 11, just as the geometric properties of each vertex 12 can be transposed to the other vertices 12.

(21) The focus is consequently on a single side 11-vertex 12 pair, and the two half-planes that are secant to the main axis X and that frame the vertex 12 are denoted P1 and P2, and the half-plane that extends from the main axis X and that frames, with the plane P2, the side 11 is denoted P3. The planes P1 and P2 thus define together a first sector S1 of the space delimited by vertex 12 (in other words, resting on the ends of the vertex 12 at the junctions with the adjacent sides 11), and the planes P2 and P1 define together a second sector S2 of the space, adjacent to the first sector S1, and delimited by the side 11 (in other words, resting on the ends of the side 11 at the junctions with the adjacent vertices 12).

(22) The annular seat 9 furthermore defines an annular rim 13 that extends in a reverse taper from an inside edge of the placement perimeter 10 and is essentially complementary to the tapered area 7 of the underlying container 1, in the vicinity of the junction of the tapered area 7 and the peripheral support face 8.

(23) In the second place, the bottom 3 comprises a central part 14 that extends from the seat 9and more specifically from an inside edge 15 of the rim 13in the direction of the main axis X.

(24) As FIGS. 2 and 3 show, the central part 14 is in two parts and comprises: A central peg 16 that has a side wall 17 that is tapered overall in revolution around the main axis X (with an angle of conicity of between 10 and 20 and preferably of approximately) 12, with this peg 16 being shaped and sized so as to completely encompass the stoppered neck 5 of the underlying container 1. An at least partially complementary arch 18 of the tapered area 7 of the shoulder 4 of the underlying container 1, with this arch 18 extending from the rim 13 in the direction of the main axis X.

(25) The side wall 17 of the peg 16 is described as tapered overall to the extent that the wall 17 could be ribbed while having, at its vertex, a more narrow width than at its base.

(26) The peg 16 is connected to the rest of the bottom 3 by a connecting fillet 19 whose radius is denoted R, measured in any plane as axial half-plane P (i.e., any half-plane that extends from the main axis X). P0 refers to a reference axial half-plane that extends from the main axis X and that passes through the center of one of the sides 11 (located on the right in FIGS. 2 and 3). Furthermore, the angle between any plane P and the plane P0, measured in the trigonometric (or counterclockwise) direction around the main axis X, is denoted A.

(27) As FIGS. 2 and 3, as well as FIGS. 5 and 6, show, the radius R of the fillet 19 is variable in revolution around the main axis X, i.e., the radius R is a variable function of A.

(28) In particular, the radius R has: A minimum value Rm in the first sector S1 delimited by the vertex 12 (or in any equivalent sector delimited by any vertex 12 of the placement perimeter 10), A maximum value RM in the second sector S2 delimited by the side 11 (or in any equivalent sector delimited by any side 11 of the placement perimeter 10).

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

(30) According to a particular embodiment illustrated in the figures, where the container 1 has plane symmetries (in relation to axial planes passing through the centers of the sides 11 or through the centers of the vertices 12), i.e., the polygon formed by the cross-section of the container (or by the placement perimeter) is regular, the minimum value Rm is measured in the bisecting plane of any sector S1 delimited by a vertex 12, and the maximum value RM is measured in the bisecting plane of any sector S2 delimited by a side 11.

(31) Thus, in the example illustrated in the figures, where the placement perimeter 10 (like the cross-section of the body 2) has a square shape, the radius R of the fillet 19 passes through four minimum values Rm (facing the vertices 12, i.e., in the bisecting planes of the vertices 12), and four maximum values RM (facing the sides 11, i.e., in the bisecting planes of any side 11).

(32) A better blow-moldabilty of the bottom 3, i.e., a greater easeand a better qualityof the shaping of the bottom 3, arises from this variability of the radius R. Actually, the relatively large value of the radius RM facing the sides 11 makes it possible, in any sector S2, to minimize the quantity of material necessary to the shaping. Taking into account the relative narrowness of the volume defined between the peg 16 and the body 2 in the container 1 (primarily when the latter is of low capacitytypically 0.5 l), a better creep of the material toward the seat 9 results because of the larger quantity of material set aside for the formation of the fillet 19 and ultimately a better surface evenness of the placement perimeter 10.

(33) According to a preferred embodiment, the radius R is continuously variable between its minimum value Rm and its maximum value RM. A curve that illustrates the variations of the radius R over a complete revolution around the main axis X was plotted on the diagram of FIG. 7, with the angle A (measured in radians) thus varying between the value zero and 2. It is seen that, taking into account the arbitrary definition of the angle zero (in the plane bisecting a side 11), the radius R has its minimum value Rm at

(34) $A=\frac{}{4},A=\frac{3}{4},A=\frac{5}{4},A=\frac{7}{4},$
angles and its maximum value RM at angles

(35) $A=0,A=\frac{}{2},A=\mathrm{et}A=\frac{2}{3}.$

(36) It will be noted that, in the illustrated example, the radius R has sinusoidal (at least by approximation) variations in revolution around the main axis X (i.e., based on the angle A).

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

(38) $2\frac{\mathrm{RM}}{\mathrm{Rm}}3$

(39) In the illustrated embodiment, this ratio is approximately 2.5:

(40) $\frac{\mathrm{RM}}{\mathrm{Rm}}2.5$

(41) As the figures, and in particular FIGS. 2 and 3, show, the radial extension of the arch 18, measured in a transverse plane (perpendicular to the main axis X), varies in a manner opposite to the radius R of the fillet 19. Thus, the radial extension of the arch 18 is maximum in the bisecting plane at any vertex 12 and minimum in the bisecting plane at any side 11. In some cases (as in the illustrated example), it may be that the radial extension of the arch 18 is zero, or close to the value zero, in the bisecting plane at any side 11. In other words, in this embodiment, the side wall 17 of the peg 16 is connected directly, via the fillet 19, to the seat 9, and more specifically to the rim 13. In this case, the arch 18 is not, strictly speaking, individual but rather is formed by a set of portions distributed angularly around the main axis X and centered on the bisecting planes of the vertices 12. This design does not impair the stability of the container. In particular, in the square embodiment illustrated, the arch 18 located in the area of the vertices 12 makes it possible to ensure sufficient support in the tapered area 7 of the underlying container 1.

(42) When, as is shown in FIG. 4, the container 1 is stacked on an underlying container 1, with the shoulder 4 of the underlying container 1 being inserted into the bottom 3 of the upper container 1: The neck 5 of the underlying container (stopper 6 included) is housed in the peg 16 of the upper container 1; The placement perimeter 10 of the upper container 1 is applied against the peripheral annular support face 8 of the underlying container 1; The outside edge of the tapered area 7 of the underlying container 1 is engaged in the rim 13 of the upper container 1; The arch 18 of the upper container 1 is applied against the tapered area 7 of the underlying container 1.

(43) As we have seen, the variability of the radius R and in particular the minimum value Rm facing the vertices 12 ensures that a smaller quantity of material is necessary for the formation of the seat 9 in the sides of the polygon, enhancing a better blow-moldability of the container 1. In particular, a better formation of the placement perimeter 10 and therefore a better stability of the container 1 are ensured, in particular when it is stacked where the compression forces exerted on an underlying container can be more evenly distributed.