EP0195149B1

EP0195149B1 - Container with closure

Info

Publication number: EP0195149B1
Application number: EP85301931A
Authority: EP
Inventors: James Moore; Catriona Grigg
Original assignee: CURVER PACKAGING Ltd
Current assignee: CURVER PACKAGING Ltd
Priority date: 1985-03-20
Filing date: 1985-03-20
Publication date: 1990-01-24
Anticipated expiration: 2005-03-20
Also published as: DE3575546D1; EP0195149A1

Description

The invention relates to a container with a closure both from plastics, the container comprising a bottom and an upright wall, which wall widens at least in its upper region toward a rim, first locking means for securing the closure to the container having been provided on the outside of the upright wall, and the closure possessing an inverted U-shaped groove which can receive the rim and part of the wall, which groove is defined by an inner skirt, an annular closure flange and an outer skirt, the latter being provided with second locking means on its inside, and, with the closure secured to the container, the outside of the inner skirt sealing the container by being tightly wedged against the inside of the container wall, and the second locking means being under the first locking means, and when the first and second locking means engage, the centre part is already sealingly wedged against the container wall along a height "a" of the wedging area, whereas between the rim and the underside of the annular flange there is still a space with a height less than the difference between the height of the wedging area and the height "a".
Such a container is known from US Patent Specification No. 3,809,284.
In this type of containers the sealing and closing functions between the container body and the closure lid have been separated in such a way that the closing function has been obtained by locking means provided on the container body and the outer skirt of the lid respectively, whereas the sealing function has been obtained by wedging the center position of the lid into the container body. In order to open such a container it is important that the dimensions of the different portions are as stable as possible and that the sealing and closing function do not interfere with each other.
The object of the invention is to improve a container-and-closure of the above-described type, so that the closure is easier to remove, also when the center part of the closure has sunk into the container to the maximum extent.
This object has been achieved in that the angles between the annular closure flange and the skirts that join it are substantially right, and in that the distance between the rim of the container and the first locking means is equal to or greater than the height of the inner skirt.
By making the container-and-closure in this way the sealing and closing functions will be independent from each other, to such an extent that even when the center part of the closure has been penetrated to the maximum depth into the container body, it does not impede the bending of the container wall in order to disconnect the closure from the container body.
Preferably, the container-and-closure assembly is designed in such a way that via an inwardly downwardly sloping transition number the inner skirt joins a substantially horizontal closure wall which has been provided with a circumferential vertical flange on its underside, and in that the U-shaped groove has along at least part of its height, from the annular closure flange downwards, a radial width between the inner skirt and the outer skirt which equals a uniform wall thickness of the position of the container wall located above the first locking means.
It has been found that a closure as described above can be injection moulded with a much greater dimensional stability than other known closures. By a greater dimensional stability is meant here that the closures ultimately obtained after cooling, have dimensions differing within much narrower limits than usual. This phenomenon could not be predicted, nor can it be explained or calculated. Also, with the above-described design of the top section of the container a much greater dimensional stability can be achieved. It has been found that by making the top section of the container equally thick in all places, and not providing beads, flanges or ribs, the process of cooling the mould can be controlled much better and the shrinkage occuring during cooling can be predicted much better, so that, again, dimensional deviations in the containers produced are within much narrower limits. The higher dimensional stability is advantageous in that it permits better definition of the wedging area of the container-and-closure assembly.
The absence of ribs, beads, flanges and other thickened parts from the upper region of the container wall offers a number of advantages. In the first place, the groove width and hence the width of the annular closure flange can be small, so that a closure is prevented from being drawn into the container under a load. A wide flange which is drawn into the container exhibits a much higher degree of concave radial flexure, viewed from above, than a narrow flange. This lower degree of flexure of a narrow flange, which is also contributed to by the right angles between the annular cover flange and the two skirts, makes it more difficult for the outer skirt to be drawn over the rim into the container. In the second place, the part of the container wall received into the groove is more flexible, so that it conforms better to the groove, resulting in improved leak-tightness. In the third place, no sink marks occurs on the sealing face of the container wall, resulting in improved sealing properties. Sink marks are depressions on plastics surfaces formed by shrinkage during cooling when on the other side of the walls thickened spots have been provided.
Because the first locking means can be located at substantially the same level as where the transition between inner skirt and transition member occurs when a closure has been fitted to the container, the components together provide a unique resistance to radial compression of the container, thereby substantially obviating a source of leakage.
The first locking means may comprise a rib or flange around the container.
The second locking means may comprise a round-going rib on the inside of the outer skirt of the closure.
The container and the closure may be made of the same material suitable for injection moulding or from different materials suitable for injection moulding, such as homopolymers of ethylene and propylene, copolymers of ethylene and/or propylene, and mixtures of these (co)polymers.
On account of its good sealing properties, its good stackability, its robustness and its easily fittable and removable closure, the container according to the invention is eminently suitable as a nestable, single-service packaging bucket for solids, pastes and liquids.
The invention will hereinafter be explained in detail with reference to an embodiment represented in the drawing.
In the drawing,

Fig. 1 is a closure according to the invention, half in axial cross section and half viewed from the side;
Fig. 2 shows a container according to the invention, half in axial cross section and half viewed from the side;
Fig. 3 shows a container and a closure according to Fig. 1 and Fig. 2, with the first and second locking means engaging, and
Fig. 4 shows a container and a closure according to Fig. 1 and Fig. 2 with the first and second locking means being apart.

The closure 1 in Fig. 1 has a sunk centre part 2, which is composed of an inner skirt 3, which via an inwardly downwardly sloping transition member 4 joins a substantially horizontal closure wall 5, which on its underside has been provided with a circumferential vertical flange 6. Via a right angle, the inner skirt 3 joins an annular closure flange with underside 8, which in turn via a right angle joins the outer skirt 9, which has a portion 10 parallel with the inner skirt 3 and a widened portion 11. On the inside of the outer skirt second locking means have been provided in the form of a round-going rib 12 with top 13. The groove 14, in the shape of an inverted U, is formed by the components 3, 7 and 9 and possesses a portion 15, from the underside 8 of the annular closure flange 7 downwards, which has a radial width 'd'.
The container 16 drawn in Fig. 2 has a bottom 17 and an upright wall 18 which gradually widens towards a rim 19 so that the containers can be nested one in the other. On the outside of the container wall are first locking means in the form of a rib 20 around the container with an underside 21. The wall thickness of the upright wall 18 is 'd' and equals the radial width of part 15 of the U-shaped groove 14 between the inner skirt 3 and the outer skirt 9. The portion of the container wall 18 which is located above the rib 20 has a height which virtually equals the height of the inner skirt 3. The distance 'h1' between the underside 21 of the rib 20 and the rim 19 of the container is smaller than the distance 'h2' in Fig. 1, between the top 13 of rib 12 and the underside 8 of the closure flange 7. When the closure has been placed on the container 16 as drawn in Figure 3, with a top 13 of the rib 12 engaging the underside 21 of rib 20, there is a space 22 left between the underside 8 of the annular closure flange 7 and the rim 19 of the container, into which space the upright wall 18 can slide when the closure is lowered. In the position drawn in Fig. 3, the outside of the inner skirt 3 is already wedged against the inner surface of the upright wall 18, so the centre part 2 has already entered the wedging area along, for example, a distance 'a'. For the sake of clarity, in Fig. 3 a line 1 has been drawn on which the wedging height of the wedging area has been indicated as the distance PQ. The distance PR equals 'a'. In the position drawn, the height of the space 22 between the rim 19 and the underside 8 of the annular closure flange is smaller than the wedging height PQ minus PR, so that when the centre part has been pushed so far into the container that the underside 8 of the annular flange 7 rests on the rim 19, the centre part 2 is still in the wedging area. The rib 12 has then also disengaged from the rib 20, as drawn in Fig. 4.
In use, the closure if fitted to the container in the position according to Fig. 3. If on account of tensile stress in the outer skirt the rib 12 is difficult to pull from under the rib 20, by pressing on the closure the rib 12 can be disengaged from rib 20 so that the preliminaries for removal of the closure are easier to perform.
Stacking a large number of containers one on the other does not result in increased stress between the locking means.
The rib 20 can also be provided in a lower position, as indicated by 20' in Fig. 3. The outer skirt 19 will then have to be adapted accordingly, so that the rib 12 also comes in a lower position; see 12' in Fig. 3. The resulting configuration is indicated by dotted lines.

Claims

1. A container (16) with a closure (1) both from plastics, the container comprising a bottom (17) and an upright wall (18), which wall widens at least in its upper region toward a rim (19), first locking means (20) for securing the closure (1) to the container (16) having been provided on the outside of the upright wall (18), and the closure (1) possessing an inverted U-shaped groove (14) which can receive the rim (19) and part of the wall (18), which groove (14) is defined by an inner skirt (3), an annular closure flange (7) and an outer skirt (9), the latter being provided with second locking means (12) on its inside, and, with the closure (1) secured to the container (16), the outside of the inner skirt (3) sealing the container (16) by being tightly wedged against the inside of the container wall (18), and the second locking means (12) being under the first locking means (20), and when the first and second (12) locking means engage, the centre part (2) is already sealingly wedged against the container wall (18) along a height "a" of the wedging area, whereas between the rim (19) and the underside of the annular flange (7) there is still a space with a height less than the difference between the height of the wedging area and the height "a", characterized in that the angles between the annular closure flange (7) and the skirts that join it are substantially right, and in that the distance between the rim (19) of the container (16) and the first locking means is equal to or greater than the height of the inner skirt (3).

2. A container according to claim 1, characterized in that via an inwardly downwardly sloping transition member (4) the inner skirt (3) joins a substantially horizontal closure wall (5) which has been provided with a circumferential vertical flange (6) on its underside, and in that the U-shaped groove (14) has along at least part (15) of its height, from the annular closure flange (7) downwards, a radial width between the inner skirt and the outer skirt which equals a uniform wall thickness of the position of the container wall located above the first locking means.

3. A container according to claim 2, characterized in that the first locking means (20) comprises a rib provided around the container (16).

4. A container according to claim 2 or 3, characterized in that the second locking means (12) comprises a rib provided on the inside of the outer skirt (9).