GB2294451A

GB2294451A - Moulded containers

Info

Publication number: GB2294451A
Application number: GB9507410A
Authority: GB
Inventors: Alan Albert Haig
Original assignee: Linpac Plastics Ltd
Current assignee: Linpac Packaging Ltd
Priority date: 1994-10-26
Filing date: 1995-04-10
Publication date: 1996-05-01
Anticipated expiration: 2015-04-10
Also published as: NL1001468C2; GB9507410D0; GB2294451B; NL1001468A1

Abstract

A container such as a doughnut box comprises a lid (1) and a base (1') which are movable relatively between open and closed positions and which incorporate means for retaining the lid in its closed position relative to the base, wherein each of the lid (1) and base (1') has a region (10, 20) defined by an outer edge thereof and said retaining means comprises a first retaining portion (13) and a second retaining portion (13') which extend substantially diagonally across the respective regions (10, 20) and form a releasable snap-fit closure. The lid and base (1, 1') are preferably moulded integrally and hinged together. Apparatus for forming the container comprises no more than two ejector rods for stripping the container from a mould. <IMAGE>

Description

CONTAINER AND ITS MANUFACTURE DESCRIPTION The present invention relates generally to a container and its manufacture, the container, a boxlike container (hereinafter referred to as a "box"), particularly, though not exclusively, being intended for the temporary storage, distribution, transportation, displayand or the serving of a comestible product. The box with which the invention is particularly concerned is intended for use with a comestible product known as a doughnut and in this specification the box intended for such use will be referred to as a doughnut box.

The invention is also concerned with a method of, and apparatus for, manufacturing the box.

Boxes for comestible products, especially doughnut boxes, are well known. Generally, they are manufactured of a transparent plastics material.

These are lightweight, cheap to manufacture, and convenient to use.

A known type of doughnut box comprises a base and lid both of which are recessed in form. The base and lid are hinged together along a pair of mutually adjoining edges, so that they may be moved relatively between open and closed conditions of the box. Means are provided such that, in the closed position, the lid is positively retained relative to the base in order to prevent accidental opening, to protect the interior of the box against ingress of foreign bodies and generally to facilitate transport and storage of the box with its contents.

One known type of doughnut box is of generally polygonal shape, when seen in plan view, having four sides and four generally squared or rounded corners.

The means for retaining the lid in the closed position relative to the base may be provided by a resilient lip on either the lid or base which may spring or snap over, to be retained by, a cooperable edge on the respective base part or lid part. The resilient lip and cooperable edge extend fully to and around the corner regions of both the lid and base at those two corners of the box which are opposite the mutually adjoining, hinged edges of the lid and base.

In a second known type of box, generally similar to the first, button-type closures are provided at the respective two corners opposite the mutually adjoining hinged edges of the lid and base. Each button-type closure comprises a recess on one of the base and lid and a cooperable projection on the other of the base and lid.

In yet another known type of box, the lip and cooperable edge type closure of the first known type may be combined with the button-type closure of the second known type.

These known types of box suffer from a number of disadvantages. Firstly, personnel who are to use the known types of box, require to be trained in the proper functioning of the box, especially to ensure that they understand and can reliably operate the box in order to ensure proper closure of the lid to the base and can open the lid easily and quickly. The known closure means are generally unreliable in operation. The lip and cooperable edge type of closure means is particularly susceptible to accidentally springing open, whilst the button-type closure means can be difficult to engage initially, and, once engaged, can be difficult to disengage. It is particularly important in the catering industry, in which the doughnut box will normally be used, for untrained personnel to be able to manipulate the box with ease and certainty.It is also desirable for a purchaser of the comestible product to be able to open the box more readily to gain access to the product.

There are also disadvantages which arise in the manufacture of these know types of box, especially the type having the button-type closure. In the buttontype closure, the projection (or "button") has a height of, typically, a few millimetres and its sidewall is slightly indented in order to improve the security of the fit within the recess which forms the co-operable portion of the closure. Thus, the shape of the button is produced by a complementarily-shaped recess in the mould on which the lid or base is formed. Such mould recess has an undercut and this gives rise to a tendency of the lid or base to be retained by the mould after forming.

Conventional air jets have proved ineffective as a means of releasing the lid or base from the mould.

Further the provision of mechanical ejectors in the form of rods which may be advanced to contact the product and press it from the mould is problematical.

This is because the design of the apparatus on which the lid and base are contact pressure formed is such as to reduce material losses by trimming to the minimum. This leaves little space for the requisite number and type of ejector mechanisms to be accommodated within the perimeter of the mould.

It is an object of the present invention to eliminate, or at least substantially reduce, the disadvantages associated with the known types of box described above and their manufacture.

The invention accomplishes this object by providing an improved method of, and apparatus for, manufacturing the box, and an improved arrangement of closure means for retaining the lid and base in the closed condition of the box.

The present invention arises from the concept of providing a closure means comprising a straight reinforced lip which extends at an angle across a region of one of the lid and base, which lip can fit into a correspondingly angled, straight undercut across a region of the other of the lid and base.

This angled, straight arrangement of the closure means leaves a residual area, on one of the lid and base, between the angled, straight formation and the outer edge. This residual area creates space for a mechanical ejector effective for releasing the product from the mould Thus, an aspect of the present invention provides a container comprising a lid and a base which are movable relatively between open and closed positions and which incorporate means for retaining the lid in its closed position relative to the base, wherein a first retaining portion is provided on one of the lid and base and includes a rim portion, preferably straight, extending between a pair of points spaced along an outer edge of the lid or base, and wherein a second retaining portion is provided on the other of the lid and base and includes a straight lip portion extending between a pair of spaced points, the lip portion affording a releasable snap-fit over the rim portion of the first retaining portion in the closed position of the lid relative to the base.

When the lid and base are polygonal in shape, for example, generally square, as in the case of the preferred embodiment to be described hereinbelow, then each retaining portion extends diagonally across an actual or nominal substantially square corner region of the lid or base. If, however, the lid and base are, say, generally circular or oval or have arcuate regions defined by respective outer edges thereof, then the respective retaining portions of the lid and base may be chords extending between a pair of points spaced around the outer edge.

In either case, on at least one of the lid and base there will be an area between the first or second retaining means (as the case may be) and the outer edge, which area affords space for a mechanical ejector effective for releasing the product from an associated forming mould.

In this specification, the word "diagonally" is used to embrace not only interlocking lid and base retaining portions extending across substantially square corner regions but also retaining portions of the lid and base extending between two spaced locations on the arcuate outer edge of, say, a circular or oval lid or base.

Preferably, the retaining portions are generally straight but need not necessarily be so.

In the preferred embodiment, a first corner region is provided on one of the lid and base and includes a protruding rim angled substantially diagonally i.e. at 45", thereacross between a pair of adjacent outer side edges, and a second corner region provided on the other of the lid and base and includeing a recessed lip angled substantially diagonally i.e. at 45 , thereacross between a pair of adjacent outer side edges. The protruding rim and recessed lip constitute the respective retaining portions of the lid and base.

Preferably, the recessed lip is generally Sshaped when seen in cross-section, with a lower, inwardly protruding rim portion and an upper recess portion. In the relatively closed position of the lid and base, the protruding rim on the lid or base is received in the recess portion of the lip on the base or lid and is retained therein by the protruding rim portion of the lip.

Preferably, each of the lid and base has another region, such as a corner region, similarly formed to the first such corner region and defined by another pair of outer side edges thereof, one of the outer side edges being common to the former pair of outer side edges. Thus, retaining means in accordance with the concept of the invention, may be provided at each end corner of one side of the box.

By virtue of the provision of retaining means in the form of pairs of respective interlocking lid and base retaining portions extending substantially diagonally across regions of the lid and base, a very positively interlocking closure for the box is provided, which, nevertheless, is easily releasable when required. Moreover, by the provision of these closure means at two adjacent corners of, say, a square box, there is a substantial gain in the rigidity of the box as a whole.

Preferably, the base or the lid or both is or are provided with a side wall depression intended to act as a finger grip which facilitates gripping of the box during opening of the lid. The side wall depression(s) also contribute substantially to the rigidity of the base and/or lid.

The inventive box with its improved closure means is more readily usable by untrained personnel than the prior art boxes, gives a more reliable closure and is more easily opened when required.

Another aspect of the present invention provides apparatus for forming a container comprising a lid and a base which are movable relatively between open and closed positions and which incorporate means for retaining the lid in its closed position relative to the base, the apparatus comprising respective first and second mould portions for forming the lid and base, one of the first and second mould portions affording a first mould surface for forming on one of the lid and base a rim portion, preferably straight, extending between a pair of points spaced along an outer edge of the lid or base, and the other of the first and second mould portions affording a second mould surface for forming on the base or lid a lip portion, preferably straight, extending between a pair of spaced points, the second mould surface being shaped to form said lip portion so as to afford a releasable snap fit over said rim portion formed by the first mould surface, for retaining the lid in its closed position relative to the base.

Another aspect of the present invention provides apparatus for forming a container having container portions comprising a lid and base which are movable relatively between open and closed positions, the apparatus comprising a mould portion having an outline shape defining a container portion having an outer edge, the mould portion affording within the periphery of said outline shape a mould surface extending, preferably in a substantially straight line, between a pair of points spaced along said outline shape, and ejector means disposed between said mould surface and the periphery of said outline shape; said mould surface being constructed to form on the corresponding container portion a retaining portion constituting part of a closure means of the container.

Another aspect of the present invention provides a method of forming a container comprising a lid and a base which are movable relatively between open and closed positions and which incorporate respective first and second means for retaining the lid in its closed position relative to the base, the method comprising forming on one of the lid and base, first retaining means including a first retaining portion which includes a rim portion, preferably straight, extending between a pair of points spaced along an outer edge of the lid or base, and on the other of the lid and base second retaining means including a lip portion, preferably straight, extending between a pair of spaced points, the lip portion being formed to afford a releasable snap fit over the rim portion of the first retaining portion in the closed position of the lid relative to the base.

Yet another aspect of the present invention provides a method of forming a container having container portions comprising a lid and a base which are movable relatively between open and closed positions, the method comprising forming by means of a mould a container portion having an outer edge and, within the periphery of said outer edge a retaining portion, preferably straight, extending between a pair of points spaced along said outer edge, the retaining portion constituting part of a closure means of the container; the method further comprising operating an ejector means which is effective against a region of the container portion disposed between said straight retaining portion and said outer edge to at least partially assist in ejecting said container portion from the mould.

In order that the features and advantages of the present invention may be better understood, a detailed description of a presently preferred embodiment of doughnut box will now be given, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a lid of a prior art doughnut box; Figure 2 is a perspective view of a lid of the doughnut box of the present invention; Figure 3 is a perspective view a base of the doughnut box of the present invention; and Figure 4 is a side view, seen in the direction of the arrows A in Figures 2 and 3 of part of the box in its closed position.

Referring to Figure 1 of the accompanying drawings there will be seen a lid P of a prior art doughnut box. The lid P is usually manufactured of a transparent plastics material, typically that known as oriented polystyrene (OPS). The lid P is of polygonal, here shown as substantially square, shape when seen in plan view, and has a rear edge 2 which will form a hinged connection with a similar rear edge of a base (not shown) allowing relative pivotal movement between the lid and base along the rear edge of the box.

The prior art lid P further comprises an upwardly recessed, approximately square domed formation, having two outwardly protruding rounded corner regions 4 at its rearward edge 2. At its front edge, the lid 1 has a side wall depression 8 at each of the two front corner regions. The upper, substantially planar surface of the lid P has a central area 5 on which may be formed one or more strengthening formations 6.

Such strengthening formation(s) 6 is/are typically formed in relief on the region 5 and may be in the form of a logo. Surrounding the region 5, and along each of the four sides of the upwardly recessed dome of the lid P, are finger formations 7 of scalloped form. These act additionally as strengthening means for the upwardly recessed dome formation. At the base of the upwardly recessed dome formation, the lid P is provided with a substantially planar rim 9.

At the ends of the front edge of the lid P, there are provided rounded corner regions 10, each defined by a pair of adjacent outer edges of the lid P, namely the front outer edge and the adjacent outer side edge, joined by a curved edge portion.

Each of the corner regions 10 includes a first portion 30 of a button-type closure, the portion 30 here being illustrated diagrammatically as a projection or button projecting downwardly from the planar rim 9 within the corner region 10. The button 30 has a slightly raised central region surrounded by an annular groove whose base lies a few millimetres below the level of the planar rim 9. Thus, the button has a generally circular sidewall normal to the planar rim 9 and, seen in side view, this sidewall is slightly indented between the planar rim 9 and groove base.The purpose of this indentation, which extends right around the sidewall, is to strengthen the button against collapse during engagement within a complementary recess of a base (not shown) of the prior art doughnut box and to provide for a secure fit within such recess to retain the lid P in its closed position relative to the base.

The prior art lid P and its complementary base are manufactured by a known process of contact pressure forming. In this process, which will only briefly be described, a tensioned sheet of the desired OPS material is placed over a heated flat anvil and held under tension and in place adjacent its edges by a peripheral knife blade which approaches the surface of the anvil with precision accuracy of a few microns spacing therefrom. This spacing is selected to give sufficient presentation for adequate retention of the OPS sheet without severing it, though it will be partially cut through.

Within the periphery of the knife blade is a mould affording one mould portion, or preferably a multiplicity of mould portions. The or each mould portion is recessed to provide a shape corresponding to that of the container or container portion to be produced. With the mould in close proximity to the anvil, jets of air passing through holes in the latter blow mould heated and t ensioned the OPS sheet against the mould portion(s), following which the mould and knife blade(s) are advanced further towards the anvil to trim away unwanted OPS sheet material and separate the so-moulded container(s) or container portion(s) therefrom.

In order to keep wastage from trimmings to a minimum, the knife blade(s) are positioned as close to the edges of the mould portion(s) as possible, which leaves little, if any, space to accommodate any mechanical ejector mechanisms for ejecting the container(s) or container portion(s) from the mould portion(s).

With the prior art button closure, the sidewall indent of the button requires a corresponding undercut in the forming mould portion, and this gives rise to retention of the moulded container or container portion to the mould portion. Air ejectors have been found unsuccessful because as soon as one edge (normally an edge other than that formed with the buttons) of the container or container portion is released from the mould portion, a low-resistance path is created for the escape of the air. Successful mechanical ejection requires the provision of two ejector rods at each corner, disposed one at each side of the button forming mould recess, but with the requirement for low trimming wastage this leaves insufficient space for the necessary mechanism.

Turning now to the present invention, reference is made to Figures 2 to 4 of the accompanying drawings which shows a presently preferred embodiment of the doughnut box of the present invention. There will be seen a lid 1 and a base 1'. Each of the lid and base 1, 1' is preferably manufactured of a transparent plastics material, more preferably that known as oriented polystyrene (OPS). Each of the lid and base 1, 1' is of polygonal, here shown as substantially square, shape when seen in plan view, and has a rear edge 2, 2', which edges are already connected together in some suitable way, for instance a weakened line of juncture, to form a hinged connection allowing relative pivotal movement between the lid and base along the rear edge of the box.

With particular reference to Figure 2, the lid 1 has the same basic form as the lid P of the prior art doughnut box, and like reference numerals are used in Figures 1 and 2. Thus, the lid 1 further comprises an upwardly recessed, approximately square domed formation, having two outwardly protruding rounded corner regions 4 at its rearward edge 2 although side wall depressions similar to depressions 8 at the front edge may alternatively be provided at its rearward edge.

With reference to Figure 3, the base 1' will be seen to be generally similar in overall structure to the lid 1, differing therefrom mainly in detail of the front edge corner regions. Thus, the base 1' comprises a recessed, in this case downwardly, approximately square shaped domed formation 3', having a pair of rear edge, rounded corner protrusions 4' (or sidewall depressions similar to depressions 8' mentioned below), a central base area 5', and one or more stiffening formations 6'. There are also finger and strengthening formations 7' and a surrounding rim 9'. At the ends of the front edge of the base 1', two corner regions 20 have side wall depressions 8' similarly to the side wall depressions 8 of the lid 1.

Each of these two corner regions 20 of the base 1' comprises an innermost area 10' commencing from an arcuate line 12' afforded by the junction of the side wall depression 8' with the corner region 20.

Outwardly of the innermost area 10' is a channel 15 defining an outermost protruding rim 13' angled substantially diagonally i.e. at 45", across the corner region 20 between the pair of adjacent outer front and side edges of the base 1'. Between the channel 15 and the protruding rim 13' is a narrow lip 16. The channel 15 gives rigidity to the corner region 20.

Thus, the recessed lip 13 of the lid 1 and the lip 16 of the base 1', which extend substantially diagonally across the corner regions 10,20 of the lid 1 and base 1', respectively, between respective pairs of adjacent outer front and side edges thereof, provide respective retaining portions of the lid 1 and base 1' which enable the lid 1 to be retained in its closed position relative to the base 1'.

As can be seen further in Figure 4, each lip 16 of the base 1' engages in the corresponding recessed lip 13 of the lid 1 in interlocking relationship therewith, to retain the lid and base in the closed position.

Apparatus according to the present invention, for making the box of the invention is broadly similar to the prior art apparatus earlier described and, so, will not be described in detail. Where it differs is in the shape of the mould portion(s), especially at the corner regions thereof, and the arrangement of mechanical ejectors.

In the lid 1 of the box of the invention, the lower inwardly protruding rim portion of the recessed lip 13 is produced by an undercut surface of the mould portion running diagonally across the corner region of the mould portion. During contact pressure forming, this undercut, at each of two adjacent corner regions of the mould portion, will result in the lid being retained in the mould portion. If the box is formed as a single entity i.e. with the lid and base moulded in one piece and joined along a line of weakening, this retention force may be sufficient, depending on the degree of undercut, to prevent the box as a whole from being demoulded even though the base may break free from the mould portion.

To overcome such retention, mechanical ejector rods are used and, in accordance with the present invention only one such rod is provided at each corner region of a mould portion, being disposed between the undercut surface of the mould portion and the extreme outer edge of the mould portion, that is within the area of the mould portion which will produce the triangular shaped outermost area 11.

The method of the present invention is also broadly similar to the earlier-described prior art method, but differs in the moulding of the corner regions of the lid and base of the box of the invention, and the manner of ejection from the mould.

In the moulding of the lid and base the recessed lip 13 is formed on the lid 1 to extend diagonally across each of two adjacent corner regions along the front edge opposite the rear edge 2 and the protruding rim 13' is forned on the base 1 to extend diagonally across each of two adjacent corner regions along the front edge opposite the rear edge 2'. The other details of the lid 1 and base 1' front edge corner regions 10, 20, as already described and illustrated with reference to Figures 2 to 4, are moulded concurrently with the formation of the recessed lip 13 and protruding rim 13'.

Following the moulding step, the lid 1 is acted upon, in each triangular area 11, by a respective single ejector rod advanced to exert pressure thereon to demould the lid, and box as a whole, if formed in one piece, from the mould portion. This produces on the lid 1 a slight depression 14.

By virtue of the shapes of the corner regions 10,20 of the box of the present invention, namely, the lid 1 having relatively square corner regions and the base 1' having 45" corner regions, only two demoulding ejectors need to be accommodated and this is readily possible in the space available. This compares with the need for four ejectors if both lid 1 and base 1' were to have generally square corner regions (as in the described prior art box), there being insufficient space for the mechanism associated with these ejectors. Moreover, the action of the ejectors on the triangular area 11, between the recessed lip 13 and outer edge of the lid 1, is very positive and produces a clean separation of the recessed lip 13 from the undercut surface of the mould portion.

Due to the resilience of the material from which the lid 1 and base 1' of the box are moulded, the lid can be opened easily by causing the recessed lip 13 of the lid to be snapped and sprung off the lip 16' of the base, thereby permitting the box to be opened by relative pivotal movement between the lid and base, allowing access to the contents of the box.

It is appreciated that, in accordance with the invention, other retaining portions of the lid 1 and base 1' may be employed. As mentioned above, the box components, namely the lid 1 and base 1', may be circular or oval, in which case such retaining portions thereof may be in the form of chords extending across the arcuate edges of the lid and base.

Claims

1. A container comprising a lid and a base which are movable relatively between open and closed positions and which incorporate means for retaining the lid in its closed position relative to the base, wherein a first retaining portion is provided on one of the lid and base and includes a rim portion, preferably straight, extending between a pair of points spaced along an outer edge of the lid or base, and wherein a second retaining portion is provided on the other of the lid and base and includes a lip portion, preferably straight, extending between a pair of spaced points, the lip portion affording a releasable snap-fit over the rim portion of the first retaining portion in the closed position of the lid relative to the base.

2. A container according to claim 1, wherein the lid and base are polygonal in shape and each retaining portion extends substantially diagonally across the respective corner region thereof.

3. A container according to claim 1, wherein the lid and base are generally circular or oval in shape or have arcuate regions defined by respective outer edges thereof, and the respective retaining portions of the lid and base extend between a pair of points spaced along the outer edge.

4. A container according to calim 1, 2 or 3, wherein the retaining portions are generally straight.

5. A container according to any preceding claim, wherein a first corner region is provided on one of the lid and base and includes a protruding rim angled substantially diagonally thereacross between a pair of adjacent outer side edges; and a second corner region is provided on the other of the lid and base and includes a recessed lip angled substantially diagonally thereacross between a pair of adjacent outer side edges; the protruding rim and recessed lip constituting respective retaining portions of the lid and base.

6. A container according to claim 5, wherein the recessed lip is generally S-shaped when viewed in cross-section, with a lower, inwardly protruding rim portion and an upper recess portion, such that in the relatively closed position of the lid and base, the protruding rim of the lid or base is received in the recess portion of the lip on the base or lid and retained therein by the protruding rim portion of the lip.

7. A container according to any preceding claim, wherein one of the lid and base has another region affording another first retaining portion similarly arranged to the first-mentioned first retaining portion, and the other of the lid and base has another region affording another second retaining portion similarly arranged to the first-mentioned second retaining portion, whereby there are two retaining means spaced along the outer edge of the container.

8. A container according to claim 5 or 6, or claim 7 when appended thereto, wherein each of the lid and base has another corner region similarly formed to the first corner region and defined by another pair of outer side edges thereof, one of the latter pair of outer side edges being common to the former pair of outer side edges, to provide retaining means at each end corner of one side of the container.

9. A container according to any of claims 5 to 8, wherein the protruding rim is angled substantially at 45-, and the recessed lip is angled substantially at 45-, between a respective pair of adjacent outer side edges.

10. A container according to any preceding claim, wherein the lid and base are hinged together.

11. A doughnut box substantially as hereinbefore described with reference Figures 2 to 4 of to the accompanying drawing.

12. Apparatus for forming a container comprising a lid and a base which are movable relatively between open and closed positions and which incorporate means for retaining the lid in its closed position relative to the base, the apparatus comprising a first due portion and a second mould portion for forming a respective one of the lid and base, one of the first and second moulds portions affording a first mould surface for forming on the lid or base a rim portion, preferably straight, extending between a pair of points spaced along an outer edge of the lid or base, and the other of the first and second mould portions affording a second mould surface for forming on the base or lid a lip portion, preferably straight, extending between a pair of spaced points, the second mould surface being shaped to form said lip portion so as to afford a releasable snap fit over said rim portion formed by the first mould surface, for retaining the closed position of the lid relative to the base.

13. Apparatus for forming a container having container portions comprising a lid and a base which are movable relatively between open and closed positions, the apparatus comprising a mould portion having an outline shape adapted to form a container portion having an outer edge, the mould portion affording within the periphery of said outline shape a mould surface extending, preferably in a substantially straight line, between a pair of points spaced along said outline shape, and an ejector means disposed between said mould surface and the periphery of said outline shape; said mould surface being constructed to form on the container portion a retaining portion constituting part of a closure means of the container.

14. Apparatus according to claim 12 or 13, wherein there is provided a mould affording a plurality of mould portions arranged within the outer periphery of the mould, the mould being associated with blade means extending around the periphery of the mould and between the mould portions.

15. Apparatus according to claim 14, wherein each mould portion affords a lid-forming mould portion and a base-forming mould portion arranged in close juxtaposition for forming a container lid and container base as a unitary moulding, said blade means extending around the paired lid-forming and baseforming mould portions.

16. Apparatus according to claim 15, wherein no more than two ejector rods are associated with each mould portion for releasing a container or container portion from the mould portion.

17. Apparatus according to any one of claims 12 to 16, wherein a mould portion for forming a container lid or base is of generally polygonal outline shape affording at least two corner regions, each corner region being defined between an outer edge of the mould portion and a mould surface extending substantially diagonally between a pair of points spaced along said outer edge, and wherein no more than two ejector rods are associated with the mould portion, each such ejector rod being disposed at a respective corner region.

18. Apparatus according to any one of claims 12 to 17, further including a heatable anvil formed with holes for passage of air therethrough, the mould or mould portion(s) being arranged above the anvil and being relatively movable toward and away from the anvil between a first relatively open position, a second partially closed position for moulding, and a third fully closed position for trimming.

19. A method of forming a container comprising a lid and a base which are movable relatively between open and closed positions and which incorporate means for retaining the lid in its closed position relative to the base, the method comprising forming on one of the lid and base a first retaining portion which includes a rim portion, preferably straight, extending between a pair of points spaced along an outer edge of the lid or base, and on the other of the lid and base a second retaining means which includes a lip portion, preferably straight, extending between a pair of spaced points, the lip portion being formed to afford a releasable snap-fit over the rim portion of the first retaining portion in the closed position of the lid relative to the base.

20. A method of forming a container having container portions comprising a lid and a base which are movable relatively between open and closed positions, the method comprising forming by means of a mould a container portion having an outer edge and, within the periphery of said outer edge a retaining portion, preferably straight, extending between a pair of points spaced along said outer edge, the retaining portion constituting part of a closure means of the container; the method further comprising operating an ejector means which is effective against a region of the container portion disposed between said straight retaining portion and said outer edge to eject said container portion from the mould.

21. Apparatus for forming a container substantially as herein described with reference to Figures 2 to 4 of the accompanying drawing.

22. A method of forming a container substantially as herein described with reference to Figures 2 to 4 of the accompanying drawing.

23. A container or container portion when made using the apparatus of any one of claims 12 to 18 and 21 or by the method of any one of claims 19, 20 and 22.