GB2103990A

GB2103990A - Moulding containers

Info

Publication number: GB2103990A
Application number: GB08124994A
Authority: GB
Inventors: Martin Sleath
Original assignee: Deb Chemical Proprietaries Ltd
Current assignee: Deb Chemical Proprietaries Ltd
Priority date: 1981-08-15
Filing date: 1981-08-15
Publication date: 1983-03-02
Also published as: GB2103990B

Abstract

A plastics container made by blow moulding is initially formed with an integral extension (9) on its neck (7). The extension (9) is connected with the neck (7) by means of a curved rim (10) projecting inwardly at the container mouth, and is severed from the neck (7) at (13) so that the smooth rim (10) is retained. This provides an improved container mouth with a portion (14) of the moulding remaining above the rim (10) to form a flexible seal engageable by a lid. <IMAGE>

Description

SPECIFICATION Containers This invention relates to containers.

Many plastics containers are produced by injection moulding in suitable moulds or dies but where the containers incorporate re-entrant portions it becomes difficult to remove the moulded product from the mould and movable mould parts require to be incorporated which complicates the tooling and increases the cost of the moulded product. In some cases containers of relatively small size are produced by blow moulding but the nature of the tooling used to produce blow moulded containers is such that it is best suited to the production of containers having relatively narrow mouths. Where containers having large mouths are concerned it is necessary to form an extension or "head" on the mouth of the container which is subsequently cut off to form the final product.This has the disadvantage of creating a sharp edge which is unacceptable in the case of containers into which a user's hand requires to be inserted.

It is an object of the present invention to obviate or mitigate these disadvantages.

The invention provides a process for the production of a plastics container by blow moulding comprising moulding a head or extension integrally with the mouth of the container and connected thereto by an inwardly projecting curved rim and removing the head from the container by cutting the moulding between said rim and the head at a region displaced radially outwardly from said rim whereby to form a smooth mouth to the container defined by said rim.

Preferably the line of cut is defined by an outwardly opening peripheral recess between said head and said rim and adapted to be engaged by a cutting member following moulding to sever the container from the head.

Preferably also the line of cut is arranged such that a portion of plastics material of thin flexible section remains attached to said rim to serve as a seal on attachment of a lid to the container. For this purpose the container is preferably provided with a neck having external threaded formations thereon for co-operation with complementary formations on a container lid.

The invention also provides a container formed from plastics material by blow moulding and having a mouth the inner periphery of which is defined by an inwardly directed curved rim devoid of sharp edges. The rim may be surmounted by a flexible lip formed integrally therewith and acting in associated with a lid to form a seal.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a side elevation of a blow moulded container according to the invention; and Fig. 2 is an enlarged fragmentary cross-section through the neck and mouth of the container shown in Fig. 1.

Referring to Fig. 1, the container comprises a generally cylindrical body portion 5 supported on a hexagonal base 6 and having an upwardly extending neck 7 of reduced diameter compared to the body portion 5 and provided with external threaded formations 8 for engagement with a lid or cap (not shown). The container is formed from plastics material by blow moulding and following initial moulding a "head" or extension, indicated in broken lines at 9, is attached to the mouth of the container. This head is subsequently removed by cutting to form the finished product.

Referring to Fig. 2, the neck 7 of the container is connected to the head 9 after initial moulding by means of a smoothly curved annular rim 10 which projects inwardly of the moulding at the region which will form the mouth of the finished container. The outer or rear surface of the rim 10 is formed with a pair of annular recesses 1 1 and 12, the recess 1 1 being formed immediately behind the rim 10 and the recess 12 being formed in a position closer to the head 9 and displaced radially outwardly from the curved inner surface of the rim 10. In order to form the final container the head 9 is severed from the neck 7 by a cutting mechanism engaged in the recess 12 so as to sever the two parts along the line 13.In this way the smoothly curved internal configuration of the rim 10 is retained following cutting and an upwardly and outwardly directed portion 14 is attached thereto and form a flexible seal engageable by the underside of the container lid.

It will be appreciated that since the rim 10 remains intact following the cutting operation, it present a smooth profile devoid of sharp edges and a user may therefore insert his hand into the container to remove the contents without fear of scratching or cutting. In addition the portion of the moulding remaining above the rim 10, being of a thin and resilient nature, forms a seal not hitherto present in blow moulded containers.

By virtue of the arrangement described a container may be formed by blow moulding without creating a sharp edge at the mouth of the container. Hitherto this has been possibly only by use of injection moulding techniques which require expensive and complicated tooling when producing containers having re-entrant formations. A higher through-put can also be obtained using blow moulding techniques thereby enabling a greater output to be obtained with reduced tooling costs.

Various modifications may be made without departing from the invention. For example the region at which the head is cut from the container proper may vary and various curved formations may be provided at the mouth of the container subject only to the final severing being effected at a region which is displaced radially outwardly from the inner periphery of the mouth in order that the severed edge is not contacted by a user's hand when inserted into the container. The shape and size of the container may also be varied as desired and the container need not be provided with a lid.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the applicant claims protection in respect of any patentable feature of combination of features hereinbefore referred to whether or not particular emphasis has been placed thereon.

Claims

1. A process for the production of a plastics container by means of blow moulding, the process comprising forming the container having an integral extension connected thereto by means of an inwardly projecting curved rim defining an intended mouth of the container, and removing the extension from the container by cutting the moulding between said rim and the extension at a location displaced radially outwardly from said rim, whereby to form a smooth mouth to the container defined by said rim.

2. A process according to claim 1, wherein the line of cut is defined at said location by an outwardly opening peripheral recess adapted to be engaged by a cutting member following moulding so as to sever the container from the extension.

3. A process according to claim 1 or 2, wherein the moulding is cut so that a portion of plastics material of thin and flexible section remains attached to the rim to serve as a seal on attachment of a lid to the container.

4. A process according to claim 3, wherein the container is provided with a neck having external threaded formations thereon for co-operation with complementary formations on the lid.

5. A container formed from plastics material by blow moulding and having a mouth, an inner periphery of which is defined by an inwardly directed curved rim devoid of sharp edges.

6. A container according to claim 5, wherein the rim has a flexible lip formed integrally therewith and adapted to co-operate with a lid for the container so as to form a seal.

7. A process for the production of a plastics container substantially as hereinbefore described with reference to the accompanying drawings.

8. A container formed from a plastics material substantially as hereinbefore described with reference to the accompanying drawings.