GB1600370A - Moulded nestable containers - Google Patents

Description

(54) IMPROVEMENTS RELATING TO MOULDED NESTABLE CONTAINERS (71) We, METAL BOX LIMITED, a British Company, of Queens House, Forbury Road, Reading RG1 3JH, England, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to moulded nestable containers. i.e. to containers which are moulded with a downwardly tapering shape such that they can be nested one within another, e.g. when a number of the containers are to be stacked together for storage or transport.

Difficulty can arise in separating such nested containers if they fit too closely together, and for this reason it is known to mould the containers with formations to limit entry of one container into another, for example the side walls may be formed with an external ledge, or with internal vertical ribs or nibs extending a short distance from the bottom of each container. It is also known to mould such containers with a central upward projection or punt in the bottom wall and a corresponding recess in the underside, to make moulding easier and to improve the rigidity of the container, and various proposals have been made for shaping the upward projection so that it will block entry into the recess of the projection on another such container during nesting.

An object of the present invention is to provide an improved arrangement for facilitating the separation of such nested containers.

According to the present invention. there is provided a nestable container having a side wall and a bottom wall moulded from synthetic plastics material. the bottom wall having a central projection projecting upwardly into the container interior and providing a corresponding recess in the underside of the container, wherein a plurality of substantially vertical solid ribs are provided within the recess and mutually spaced around the circumference of the same, each rib being moulded integrally with the bottom wall and projecting inwardly of the recess by a radial extent sufficient for the ribs to block or limit entry into the recess of the central projection on another such container during nesting.

With this arrangement, nested containers are effectively prevented from fitting together too closely by the blocking ribs and can thus be separated easily. The appearance of the containers is improved because the side walls can be unencumbered by moulded formations for facilitating separation. The blocking ribs may also contribute to the rigidity of the bottom of the container and to the ease of moulding.

Preferably each blocking rib occupies substantially the whole depth of the recess at its locality.

In a particular embodiment of the invention, the recess has an upwardly tapering, frustoconical outer wall and a plane, circular upper wall closing the top of the outer wall, and the blocking ribs project inwardly from the outer wall to a position which, radially of the container, is within the circular intersection formed within the container interior at the junction between the outer and upper walls of the recess.

There may be eight such blocking ribs, for example. This form of the invention is suitable for injection moulding.

A specific embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is an elevation, partly in section, of a container forming an embodiment of the invention, Figure 2 is an underneath plan view of the container of Figure 1, and Figure 3 is a detail sectional view, to a larger scale, through the side wall and part of the bottom of the container of Figures 1 and 2, also showing in chain lines part of a second similar container in nested relationship below.

In the embodiment of the invention illustrated in the drawings, the container generally indicated at 10 has a downwardly tapered conical side wall 11 and a bottom wall 11 and a bottom wall 12 which is formed with a central upward projection 13.

The projection 13 has a frusto-conical outer wall 14 and a flat circular upper wall 15.

Because the wall thickness is substantially constant, a corresponding recess 16 is formed in the underside of the container 10.

At the top, the side wall 11 has an outturned horizontal flange 17. The container is moulded from a synthetic plastics material such as polypropylene.

The conical form of the side wall 11 is such that a plurality of the containers can be nested one within another, in order to stack them for storage or transport. If the side walls 11 and bottom walls 12 were to come into close contact during nesting, however, difficulty would be experienced in separating the containers.

In order to facilitate separation, the container illustrated is provided with eight substantially vertical solid ribs or nibs 18 which extend from the conical outer wall 14 of the recess 16 for a short distance towards the centre of the recess. The height of the ribs 18 is substantially equal to the depth of the recess, so that their bottom surfaces 19 are flush with the underside of the bottom wall 12 of the container outside the recess 16.

It can be seen from Figure 3 that when the container 10 is nested within another similar container 10', the projection 13' on the lower container is prevented from entering the recess 16 by engagement with the underside of the ribs 18. The bottom wall 12' of the lower container is thus prevented from coming into contact with the bottom wall 12 of the upper container, and similarly the side wall 11' of the lower container is maintained at a short distance apart from the side wall 11 of the upper container.

Separation of the nested containers is thus facilitated.

As can be seen from Figure 3, the ribs 18 extend radially from the conical outer wall 14 of the recess to a position which is slightly closer to the centre of the recess 16 than the upper edge of its outer wall 14, i.e. which is radially within the circular intersection of the outer wall 14 with the upper wall 15, in order that the upper wall 15' of the projection 13' on lower container 10' shall engage part of the lower surfaces 19 of the ribs 18. It would nevertheless be possible for the ribs 18 to extend further towards the centre of the recess 16, or indeed to extend right across it if that were desirable for achievement of other objects, such as increased rigidity of the container.Alternatively it would be possible for the ribs 18 to be shorter than those shown in the drawing, so that their lower edges 19 did not extend as far as the upper edge of the conical outer wall 14 of the recess 16. In this case the engagement between the ribs 18 and the projection 13' on the lower container 10' would occur at the conical outer wall 14' of the projection 13', rather than at its upper wall 15' as shown, and the projection 13' would enter to a limited extent into the recess 16, though contact between the respective bottom walls 12, 12' and side walls 11, 11' would still be prevented. The free side edges 20 of the ribs 18 would in this case preferably be made parallel to the conical wall 14 of the recess 16, so as to make line contact with the conical wall 14'.

WHAT WE CLAIM IS: 1. A nestable container having a side wall and a bottom wall moulded integrally from synthetic plastics material, the bottom wall having a central projection projecting upwardly into the container interior and providing a corresponding recess in the underside of the container, wherein a plurality of substantially vertical solids ribs are provided within the recess and mutually spaced around the circumference of the same, each rib being moulded integrally with the bottom wall and projecting inwardly of the recess by a radial extent sufficient for the ribs to block or limit entry into the recess of the central projection on another such container during nesting.

2. A container according to claim 1, wherein each such blocking rib occupies substantially the whole depth of the recess at its locality.

3. A container according to claim 1 or 2, wherein the recess has an upwardly tapering, frustoconical outer wall and a plane, circular upper wall closing the top of the outer wall, and the blocking ribs project inwardly from the outer wall to a position which, radially of the container, is within the circular intersection formed within the container interior at the junction between the outer and upper walls of the recess.

4. A container according to any one of the preceding claims, wherein there are eight such blocking ribs.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. larger scale, through the side wall and part of the bottom of the container of Figures 1 and 2, also showing in chain lines part of a second similar container in nested relationship below. In the embodiment of the invention illustrated in the drawings, the container generally indicated at 10 has a downwardly tapered conical side wall 11 and a bottom wall 11 and a bottom wall 12 which is formed with a central upward projection 13. The projection 13 has a frusto-conical outer wall 14 and a flat circular upper wall 15. Because the wall thickness is substantially constant, a corresponding recess 16 is formed in the underside of the container 10. At the top, the side wall 11 has an outturned horizontal flange 17. The container is moulded from a synthetic plastics material such as polypropylene. The conical form of the side wall 11 is such that a plurality of the containers can be nested one within another, in order to stack them for storage or transport. If the side walls 11 and bottom walls 12 were to come into close contact during nesting, however, difficulty would be experienced in separating the containers. In order to facilitate separation, the container illustrated is provided with eight substantially vertical solid ribs or nibs 18 which extend from the conical outer wall 14 of the recess 16 for a short distance towards the centre of the recess. The height of the ribs 18 is substantially equal to the depth of the recess, so that their bottom surfaces 19 are flush with the underside of the bottom wall 12 of the container outside the recess 16. It can be seen from Figure 3 that when the container 10 is nested within another similar container 10', the projection 13' on the lower container is prevented from entering the recess 16 by engagement with the underside of the ribs 18. The bottom wall 12' of the lower container is thus prevented from coming into contact with the bottom wall 12 of the upper container, and similarly the side wall 11' of the lower container is maintained at a short distance apart from the side wall 11 of the upper container. Separation of the nested containers is thus facilitated. As can be seen from Figure 3, the ribs 18 extend radially from the conical outer wall 14 of the recess to a position which is slightly closer to the centre of the recess 16 than the upper edge of its outer wall 14, i.e. which is radially within the circular intersection of the outer wall 14 with the upper wall 15, in order that the upper wall 15' of the projection 13' on lower container 10' shall engage part of the lower surfaces 19 of the ribs 18. It would nevertheless be possible for the ribs 18 to extend further towards the centre of the recess 16, or indeed to extend right across it if that were desirable for achievement of other objects, such as increased rigidity of the container.Alternatively it would be possible for the ribs 18 to be shorter than those shown in the drawing, so that their lower edges 19 did not extend as far as the upper edge of the conical outer wall 14 of the recess 16. In this case the engagement between the ribs 18 and the projection 13' on the lower container 10' would occur at the conical outer wall 14' of the projection 13', rather than at its upper wall 15' as shown, and the projection 13' would enter to a limited extent into the recess 16, though contact between the respective bottom walls 12, 12' and side walls 11, 11' would still be prevented. The free side edges 20 of the ribs 18 would in this case preferably be made parallel to the conical wall 14 of the recess 16, so as to make line contact with the conical wall 14'. WHAT WE CLAIM IS:

1. A nestable container having a side wall and a bottom wall moulded integrally from synthetic plastics material, the bottom wall having a central projection projecting upwardly into the container interior and providing a corresponding recess in the underside of the container, wherein a plurality of substantially vertical solids ribs are provided within the recess and mutually spaced around the circumference of the same, each rib being moulded integrally with the bottom wall and projecting inwardly of the recess by a radial extent sufficient for the ribs to block or limit entry into the recess of the central projection on another such container during nesting.

2. A container according to claim 1, wherein each such blocking rib occupies substantially the whole depth of the recess at its locality.

3. A container according to claim 1 or 2, wherein the recess has an upwardly tapering, frustoconical outer wall and a plane, circular upper wall closing the top of the outer wall, and the blocking ribs project inwardly from the outer wall to a position which, radially of the container, is within the circular intersection formed within the container interior at the junction between the outer and upper walls of the recess.

4. A container according to any one of the preceding claims, wherein there are eight such blocking ribs.

5. A nestable container substantially as

hereinbefore described and as illustrated in the accompanying drawings.