Fluid containers or cartons

Feb. 5, 1963

J. G. SHERLOCK

FLUID CONTAINERS OR CARTONS

Filed Nov. 18, 1959

3,076,584

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INVENTOR John G Sherlock

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ATTORrMEYJ

United States Patent Office

3,076,584

Patented Feb. 5, 1963 . ¹

3,076,584

FLUID CONTAINERS OR CARTONS

John Gerrard Sherlock, Feliham, England, assignor to Plastic Packaging Limited, London, England, a company of Great Britain

Filed Nov. 18, 1959, Ser. No. 853,869

Claims priority, application Great Britain Dec. 3, 1958 2 Claims. (CL 222—541)

This invention relates to fluid containers formed of thin sheet material for holding flowable substances, whether granular or liquid such as hot or cold drinks, and particularly to containers which are sealed after filling. The term “fluid containers” is hereafter used for convenience for such containers.

Hitherto such containers have commonly been manufactured from waxed paper, and to enable the contents to be withdrawn the paper wall of the container has usually been perforated and the perforations subsequently sealed with wax, thus providing a weakened line or area in the wall of the container which can be broken to allow a drinking straw to be inserted or the contents poured off.

It is an object of the present invention to provide an improved means of access to the contents of the container which is particularly applicable to containers formed for example of a synthetic plastic material. Thus in a plastic walled container it is impracticable to provide perforations since no waxing occurs in manufacture, and it is equally undesirable to rely upon the consumer having available some puncturing instrument.

In a thin-walled fluid container according to the present invention the wall is formed with a protrusion so shaped that the base profile thereof includes a corner such that when pressure is applied to the protrusion a concentrated load is transmitted to a localized area or point of the wall adjacent the corner, which is thus ruptured.

The invention may be applied to part of the wall of the body of a container, for example to the base wall of the container or to the lid of the container and the invention therefore includes within its scope a lid for closing a container and formed with a protrusion shaped in the manner set forth above. For the purpose of simplicity in the instant specification and claims, “container element” will be used to embrace a container manufactured as an integral unit and including the protrusion of the instant invention and also a container lid or closure, for closing a container, formed with the protrusion of the instant invention.

The term “base profile” as used herein is to be understood to refer to the line formed by the junction of the surface of the protrusion with the adjacent parts of the wall of the container.

Thus according to a preferred aspect of the invention, the wall of a fluid container is formed with a protrusion comprising two flat sides which intersect on a line or edge which is inclined at a substantial angle to the general plane of the wall adjacent the protrusion, the base profiles of the two flat sides where they intersect the general plane of the wall preferably forming an angle which is less than 135°, and preferably 90°, or less.

Preferably also the edge formed by the intersection of the two flat sides is normal to the general plane of the wall where it intersects this plane, or inclined thereto at an angle of less than 30°.

In a preferred form the protrusion comprises two side side walls, which are approximately normal to the geny eral plane of the wall of the container and an inclined ^f upper wall of triangular shape, the apex of which lies at the upper end of the edge formed by the intersection of the two side walls.

In any case the protrusion is preferably formed in a well or depression in the wall concerned or is surrounded by a rim so as to be protected against accidental damage or pressure.

Conveniently the container is of generally tubular form with a base formed integrally with the side walls and a 5 lid which closes the upper end of the container after it has been filled and in such a construction the protrusion will conveniently be formed either in the base or in the lid and be protected by a rim surrounding the base or surrounding or formed on the lid.

The invention is particlularly applicable to containers formed of a synthetic plastic material such as polystyrene which is sufficiently brittle to be ruptured readily when pressure is applied to the protrusion and one construction of container according to the invention in which the in15 vention is applied to the lid is shown by way of example in the accompanying drawings, in which:

FIGURE 1 is a perspective view of the lid incorporating the invention;

FIGURE 2 is a section on the line II—II of FIGURE 20 1, but showing the manner in which the lid is applied to the upper end of a container;

FIGURE 3 is a similar view to FIGURE 2 but on the line ΠΙ—ΠΙ of FIGURE 1, and

FIGURE 4 is a similar view to FIGURE 2 but showing 25 the manner in which the lid may be ruptured by depression of the protrusion.

In the construction shown in the drawings the container 1 may consist of a circumferential wall 1 of generally tapered generally square cross-section formed integrally 30 with a base and provided at its upper end with an outwardly projecting rim 2 to which, after the container has been filled an edge portion 3 of a lid generally indicated at 4 is heat sealed in a manner known per se. Both the container and lid are formed of a thin comparatively 35 brittle synthetic plastic material such as polystyrene. As will be seen the lid is provided immediately on the inside of the rim 3 with a shallow trough-like depression 5, which serves to locate the lid on the upper end of the container prior to heat sealing, and a tapered upwardly ⁴⁰ projecting part 6 extends inwards and upwards after the manner of the base part of a pyramid from the base of the trough-like depression 5. Formed over the centre portion of the lid so as to be surrounded by a rim 6a formed by the upper edge portion of the part 6 is a de⁴⁵ pression or well having a base 7 at the centre of which is formed a protrusion, in accordance with the invention. As will be seen this protrusion comprises two flat side walls 8 and 9 which lie at approximately 90° to one another and approximately normal to the general plane of ⁵⁰ the base 7 of the well, and an inclined upper wall 10 of triangular shape, the apex 11 of which lies at the upperend of the junction edge 12 formed by the intersection of the two side walls 8 and 9. Thus, pressure applied to the apex 11 forces the parts of the two side walls 8 and 9 ⁵⁵ adjacent to their junction 12 downwards to rupture the base 7 of the well in the manner indicated in FIGURE 4. The line along which the base 7 ruptures is not completely determinate, but is generally as indicated in FIGURE 4 and in all cases, extends from the bottom of the ⁶⁰ junction 12 partially or wholly across the base 7.

It will be apparent that the rim 6a formed by the upper edge of the part 6 tends to protect the protrusion 8, 9, 10, from being accidentally damaged or depressed.

It will be readily understood that if desired, instead of forming the lid of the container in the manner indicated with a protrusion 8, 9, 10, the lid might be of other form and a protrusion of the form shown might be formed in the base wall of the container, in which event the normal procedure would be to invert the container ⁷⁰ before depressing the apex 11 of the protrusion to obtain access to the contents. It will also be readily appreciated that in such an arrangement the base of the container

3,076,584 could readily be provided, in a manner well known per se, with a rim of sufficient depth to protect the protrusion 8, 9, 10, from accidental or unintentional depression.

It would also be possible in some cases to provide a protrusion of the form shown in some other part of the wall of the container.

Again in some instances it might be desirable to form the protrusion 8, 9, 10, so that it projects inwards and to provide a tab or similar means attached to the inside of the apex 11 or of the junction 12 by which this junction can be pulled outwards to rupture the wall.