GB1563097A - Lightweight self stacking containers - Google Patents

Description

(54) IMPROVEMENTS RELATING TO LIGHTWEIGHT SELF STACKING CON TAINERS (71) We, AMALGAMATED MINING & TRADING LIMITED, of Northway Lane, Tewkesbury, Gloucestershire, a British Company, do hereby declare this 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 lightweight selfstacking plastics containers as used for packaging confectionery, cosmetic materials, haberdashery and other light objects.

It is a primary object of the invention to provide a container so shaped that a large number of such containers can be formed into a tall, stable stack. The container is also preferably designed for ease of manufacture and transport and great economy in cost.

Broadly stated, the invention consists in a self-stacking container comprising a cylindrical side wall formed from a sheet of plastics material which is bent into a hoop and secured to form an axial joint, a separately formed base and a removable lid, each moulded from a thin sheet of plastics material and each having a circular profile with a peripheral shallow cylindrical projecting flange designed to fit over the adjacent peripheral edge of the side wall, and both the base and the lid being formed with an annular projection surrounding a circular depression or an annular depression surrounding a circular projection, such that each projection or depression on the lid or base can cooperate with a corresponding depression or projection on the base or lid of a similar container stacked above or below.

Preferably, each annular projection or depression is surrounded by a flat annular surface having a surface area greater than that of the projection or depression.

Preferably, each projection has a flat top and each depression a flat bottom.

In a preferred construction the annular projection or depression has a radial diameter of approximately half the radius of the container, and a depth or height equal to approximately 1/10th the radius of the container.

Preferably, the upper and/or lower edge or rim of the side wall is formed with a bead.

The base and lid may be formed by a vacuum moulding or pressure moulding technique.

The invention may be performed in various ways and one specific embodiment will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation through a confectionery container according to the invention, and Figure 2 is a perspective view of the container.

In this example the container has a generally cylindrical side wall 10, a separately formed base 11 and a removable lid 12. The side wall is formed by wrapping or folding a continuous sheet of plastics film into a tube and forming a longitudinal seam to complete the tube after which sections of the tube are cut off each having the height of the side wall as seen in Figure 1. This short tube length then has its top and bottom edges curled over inwards to form beads 13.

The base 11 and lid 12 are both formed by a pressure moulding technique, and apart from being inverse images the two items are almost identical. Each has a peripheral shallow cylindrical wall or flange 14 designed to fit closely around the main side wall 10. In the case of the base 11 this flange 14 is rigidly secured to the side wall 10 by a cement or solvent. The base has an annular flat portion 15 surrounding an annular depression 16, which in turn surrounds a central circular projection 17, flush with the surface 15. By contrast, the lid 12 has an annular flat portion 19 surrounding an annular projection 20, which in turn surrounds a downward cen tral circular depression 21, flush with the surface 19. The dimensions of these concentric projections or depressions in the lid and base are similar.For example, the overall diameter may be 641ll, the outer diameter of the annular projection 4 4 It, and the diameter of the central projection or depression 2".

The side walls 10 and also the walls of the projections and depressions on the base and lid are slightly tapered, partly to facilitate removal from the moulding tools and partly to improve the self-stacking effect when the base of one container is placed over the lid of the container below it. It will be noted that the base 11 presents a substantial area (greater than 50So) for contact with any flat supporting surface, even if not stacked on the lid of a lower container. Also, it will be apparent from the drawings that the surface area of the outer annular surface 15 which contacts a flat supporting surface is appreciably greater than that of the depression 16.

All the components of each container are formed of a lightweight thin transparent plastics film such as modified P.V.C. or cellulose acetate, the base and lid preferably being shaped from flat sheet material by a vacuum or pressure moulding technique. The dimensions and proportions of the containers may be varied as required.

WHAT WE CLAIM IS: 1. A self-stacking container comprising a cylindrical side wall formed from a sheet of plastics material which is bent into a hoop and secured to form an axial joint, a separately formed base and a removable lid, each moulded from a thin sheet of plastics material and each having a circular profile with a peripheral shallow cylindrical projecting flange designed to fit over the adjacent peripheral edge of the side wall, and both the base and the lid being formed with an annular projection surrounding a circular depression or an annular depression surrounding a circular projection, such that each projection or depression on the lid or base can cooperate with a corresponding depression or projection on the base or lid of a similar container stacked above or below.

2. A container according to claim 1. in which each annular projection or depression is surrounded by a flat annular surface having a surface area greater than that of the projection or depression.

3. A container according to claim 1 or 2 in which each projection has a flat top and each depression a flat bottom.

4. A container according to any of the preceding claims in which the upper and/or lower edge or rim of the side wall is formed with a bead.

5. A container according to any of the preceding claims, in which the base and lid are formed by a vacuum moulding or pressure moulding technique.

6. A container according to any of the preceding claims, in which the annular projection or depression has a radial diameter of approximately half the radius of the container.

7. A container according to any of the preceding claims, in which the annular projection or depression has a height or depth equal to approximately 1/lOth the radius of the container.

8. A container according to any of the preceding claims, in which the side walls of the projections or depressions on the base and lid are tapered to facilitate removal from a mould and improve the self-stacking or nesting effect.

9. A container substantially as described with reference to the accompanying drawings.

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

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. tral circular depression 21, flush with the surface 19. The dimensions of these concentric projections or depressions in the lid and base are similar. For example, the overall diameter may be 641ll, the outer diameter of the annular projection 4 4 It, and the diameter of the central projection or depression 2". The side walls 10 and also the walls of the projections and depressions on the base and lid are slightly tapered, partly to facilitate removal from the moulding tools and partly to improve the self-stacking effect when the base of one container is placed over the lid of the container below it. It will be noted that the base 11 presents a substantial area (greater than 50So) for contact with any flat supporting surface, even if not stacked on the lid of a lower container. Also, it will be apparent from the drawings that the surface area of the outer annular surface 15 which contacts a flat supporting surface is appreciably greater than that of the depression 16. All the components of each container are formed of a lightweight thin transparent plastics film such as modified P.V.C. or cellulose acetate, the base and lid preferably being shaped from flat sheet material by a vacuum or pressure moulding technique. The dimensions and proportions of the containers may be varied as required. WHAT WE CLAIM IS:

1. A self-stacking container comprising a cylindrical side wall formed from a sheet of plastics material which is bent into a hoop and secured to form an axial joint, a separately formed base and a removable lid, each moulded from a thin sheet of plastics material and each having a circular profile with a peripheral shallow cylindrical projecting flange designed to fit over the adjacent peripheral edge of the side wall, and both the base and the lid being formed with an annular projection surrounding a circular depression or an annular depression surrounding a circular projection, such that each projection or depression on the lid or base can cooperate with a corresponding depression or projection on the base or lid of a similar container stacked above or below.

2. A container according to claim 1. in which each annular projection or depression is surrounded by a flat annular surface having a surface area greater than that of the projection or depression.

3. A container according to claim 1 or 2 in which each projection has a flat top and each depression a flat bottom.

4. A container according to any of the preceding claims in which the upper and/or lower edge or rim of the side wall is formed with a bead.

5. A container according to any of the preceding claims, in which the base and lid are formed by a vacuum moulding or pressure moulding technique.

6. A container according to any of the preceding claims, in which the annular projection or depression has a radial diameter of approximately half the radius of the container.

7. A container according to any of the preceding claims, in which the annular projection or depression has a height or depth equal to approximately 1/lOth the radius of the container.

8. A container according to any of the preceding claims, in which the side walls of the projections or depressions on the base and lid are tapered to facilitate removal from a mould and improve the self-stacking or nesting effect.

9. A container substantially as described with reference to the accompanying drawings.