Thin-walled Nestable Container

Abstract

A vacuumed formed thin-walled, plastic soft drink dispensing cup is disclosed which has a stacking structure at the lip formed by a short inwardly tapered conical section disposed between a rolled lip at the upper end and an outwardly flaired section at the lower end which forms a downwardly facing annular shoulder having an arcuate cross section adapted to mate with the rolled lip of a like cup in a nested stack.

Description

This invention relates generally to thin-walled containers and more particularly relates to cups fabricated by vacuum forming a thin sheet of thermo-plastic material and which are typically used in soft drink vending machines.

The ideal cup for use in a soft drink vending machine should have a low stacking height so that a maximum number of cups can be placed in a given storage space. Since the cups must separate by gravity to be dispensed, tight nesting is impossible because the resulting vacuum and friction makes the cups difficult to separate one at a time. Accordingly, the cup must be structured in a manner to prevent contact between the sidewalls of the nested cups, which necessarily increases the height of a stack of a given number of the cups. This stacking structure must be strong or it will be crushed when subjected to the weight of a large number of other cups and the jolts of handling and shipping. A great many structures have heretofore been proposed for accomplishing this function and have achieved varying degrees of success.

Cups used to dispense soft drinks should also have as large a cylindrical area as possible for printed advertising material. Most stacking structures located in the sidewalls interfere with the printing area. Stacking structures proposed for the bottom wall do not interfere with the printing area, but reduce usable volume and are usually difficult to form and are not sufficiently strong and reliable.

This invention is concerned with a cup having an improved stacking structure which is very strong and stable, which permits a maximum number of cups in a given stack height, which provides maximum printing area, and which further rigidifies the cup.

In accordance with the present invention, the nestable container comprises a thin unitary sheet of plastic material shaped to form a bottom sidewall, a circumferential sidewall extending upwardly and inclined outwardly from the bottom wall to form a generally conical lower section, an outwardly flaired section at the upper end of the lower conical section having an arcuate cross section, a short inwardly tapered section extending from the outer end of the flaired section and terminating in a rolled lip having a generally circular cross section. The inside diameter of the rolled lip is less than the outside diameter of the upper end of the tapered section and the tapered section has an arcuate cross section to provide a downwardly facing annular shoulder conformed to rest on a substantial area of the rolled lip of a like container in which the container is nested.

The novel features believed characteristic of this invention are set forth in the appended claims. The invention itself, however, as well as other objects and advantages thereof, may best be understood by reference to the following detailed description of an illustrative embodiment, when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation, partially in section, of a container in accordance with the present invention;

FIG. 2 is a side elevation similar to FIG. 1 illustrating a stack of three like containers in accordance with the present invention; and,

FIG. 3 is an enlarged cross section of the three nested containers of FIG. 2.

Referring now to the drawings, and in particular to FIG. 1, a container in accordance with the present invention is indicated generally by the reference numeral 10. The container 10 is formed of a thin unitary sheet of a plastic material, such as polystyrene, which has been formed from a flat sheet using conventional and well known vacuum forming processes and equipment. The particular container illustrated is the type customarily referred to as a cold drink cup, and is particularly suited for use in a machine for vending carbonated soft drinks.

The cup 10 includes a bottom wall 12 which may be of any conventional design, but is illustrated as having a recessed portion to stiffen the bottom and provide a stable base rim. A circumferential sidewall 14 extends upwardly and outwardly from the bottom wall 12 to form an inverted frustoconical section. The frustoconical section 14 terminates in an outwardly flaired section 16 which has an arcuate cross section as will be presently described in greater detail. An inwardly tapered frustoconical section 18 extends upwardly from the outer extremity of the flaired section 16, and terminates in a rolled lip 20 having a substantially circular cross section which may be formed using conventional lip rolling equipment.

Referring now to FIGS. 2 and 3, and particularly to the enlarged sectional view of FIG. 3, it will be noted that the outside diameter of the outer ends of the flaired section 16 is substantially greater than the inside diameter of the rolled lip 20. The difference in these diameters is determined by the taper and length of the upper conical section 18. Because of the fact that this inverse taper is located near the mouth of the container, the degree of taper can be substantial, typically as much as 7.degree., so that the length of the conical taper 18 can be held to a minumum and still provide a substantial overlap between the outside diameter of the flaired section 16 and the inside diameter of the rolled lip 20.

The outwardly flaired section 16 has an arcuate cross section, the outer surface of which has the same radius as the outer surface of the rolled lip 20, thus providing a large contact area. The curved shape of the flaired section 16, provides a circumferential stiffening bank of substantial strength which rests upon the rolled lip 20, which is the strongest and stiffest part of the cup. The short axial length and inward taper of section 18 makes it very strong. These three features together provide an annular band having a cross section with a straight web with oppositely turned, curved margins for maximum strength and stiffness. The large area of the contacting surfaces together with the contour of the mating surfaces provides a very stable stack. The short axial length of the inwardly tapered conical section 18 provides a stack of minimum height for a given number of containers. Additionally, substantially the entire sidewall is available for printed advertising.

Although a preferred embodiment of the invention has been described in detail, it is to be understood that various changes, substitutions, and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

What is claimed is:

1. A nestable container comprising a thin unitary sheet of plastic, the sheet being substantially uniform in thickness and being conformed to provide a circular bottom wall and a circumferential sidewall extending upwardly and outwardly as an inverted frustoconical section, the frustoconical section transitioning to an outwardly flared section to form an annular, downwardly facing concave surface having a radius of curvature, the outwardly flared section transitioning into an upwardly and inwardly tapered frustoconical section, the upwardly and inwardly tapered frustoconical section transitioning into an outwardly rolled lip having a substantially complete circular cross section with an upwardly facing convex surface, the radius of curvature of the upwardly facing convex section being equal to the radius of curvature of the downwardly facing concave surface whereby a substantial portion of the areas of the two surfaces will be engaged when like containers are telescopically nested to limit telescopic association of the containers.