Plastic container having inwardly formed flange

A plastics container has a side wall and a rim portion moulded in one piece with the side wall. The rim portion is joined to the side wall by an integral hinge portion on which it can be folded inwardly of the container. Thereby a container having an inwardly projecting rim or retaining tabs can be readily produced as a one-piece moulding. Preferably, the side wall and rim portion are inwardly concave, whereby the rim portion can be held in its inwards position by forces caused by folding.

DESCRIPTION 
This invention is concerned with a plastics container. 
It is usually necessary to provide plastics containers with projecting 
rims, e.g. for reinforcement or for attachment of lids. For technical and 
economic reasons, it has been normal to design plastics containers with 
rims projecting outwards. When moulding a container in one piece, it has 
been necessary to employ a collapsible core in the mould to obtain an 
inwardly-projecting rim. Moulds with collapsible cores are expensive and 
cooling is inefficient, thus slowing down the rate of production. It is 
also known to assemble a separately moulded rim component with a moulded 
container to provide an inwardly-projecting rim, but the time and expense 
of production are necessarily greater than for moulding containers in one 
piece with outwardly-projecting rims. 
Outwardly-projecting rims have various disadvantages. The effective 
utilisation of space during warehousing and distribution is decreased. 
Lids snapped on to outwardly-projecting rims may push each other off the 
containers, when the latter are piled together during transportation and 
the piles move relatively to each other. When the containers are being 
filled on a filling line, there is a risk of outwardly-projecting rims 
causing overturning when the containers push against each other. 
As well as avoiding or minimising the above disadvantages, 
inwardly-projecting rims have the advantage that the area available for 
decoration on the surface of the container may be increased. Also, 
inwardly-projecting rims help to prevent liquid contents from splashing 
over when containers are moved from a filling station to a lidding 
station. 
It is an object of the present invention to provide a plastics container 
which avoids or minimises the disadvantages of outwardly-projecting rims 
and of collapsible cores and separately moulded rim components. 
To this end, the invention provides a plastics container having a side wall 
and a rim portion moulded in one piece therewith, characterised in that 
the rim portion is joined to the side wall by an integral hinge portion on 
which it can be folded inwardly of the container. 
Usually, the container will be made by injection moulding. The container 
opening, at the top of the side wall, may be of any suitable shape, e.g. 
circular, elliptical or angular or partly of such shape. 
Desirably, the hinge portion is of substantially less thickness than the 
rim portion and side wall. 
Preferably, the side wall and rim portion are inwardly concave, whereby the 
rim portion can be held in its inwards position by forces caused by 
folding. 
The rim portion may extend continuously around the container. 
Alternatively, there may be a plurality of rim portions spaced apart from 
one another around the container or a single rim portion may extend for 
part of the way round the container. 
It may sometimes be advantageous to provide at least two co-extensive rim 
portions connected to each other by an integral hinge portion whereby the 
coextensive rim portions can be folded inwardly of the container. With 
such a multi-hinged arrangement, a thicker rim can be obtained. 
In addition to acting as a reinforcement, the rim portion may be shaped for 
releasably securing a lid on the container. For example, it may be shaped 
with a thread to accept a screw cap and/or with a bead to accept a snap-on 
lid. In such cases, the rim portion will have been folded inwards prior to 
lidding. 
Said side wall may have an internal recess for supporting said rim portion 
when folded inwardly. In this way, the hinge may be relieved of load and 
there is little or no risk of the hinge breaking even if a heavy load is 
placed on the lid. 
In one embodiment of the invention, said side wall has an internal recess 
so formed that when the rim portion is folded inwardly there is a 
clearance between the rim portion and an upwardly-directed surface of the 
recess for accommodating a lid. In this case, the lid is applied before 
folding the rim portion inwardly. 
The rim portion and the inside of said side wall may be provided with 
complementary profiled formations (e.g. axially extending ribs) which 
intermesh when the rim portion is folded inwardly. Such a construction 
will increase the circumferential stiffness of the open container. 
The rim portion may have at least one projection which extends upwardly 
when the rim portion is folded inwardly. Such a projection may prevent a 
lid from being pressed down into the container when loaded. 
In one arrangement according to the invention, the container has a lid, the 
lid and said rim portion being so formed that, when the rim portion is 
folded inwardly and the lid is applied, the lid and container engage each 
other at two axially spaced positions, the distance between the engagement 
positions on the container being greater than the distance between the 
engagement positions on the lid before the latter is applied, whereby 
after the lid has been applied it is axially tensioned. 
The container and/or a lid therefore may be provided with at least one 
recess or projection for opening. 
The rim portion and a lid for the container may be so formed that the 
inwardly-folded rim portion is locked in position by the lid, whereby the 
rim portion has to be peeled off along said hinge portion to permit 
removal of the lid. Thus, as well as reinforcing the edge of the 
container, the rim portion can function as a safety device for the lid in 
order to improve drop resistance and/or as a pilfer-evident closure. 
The container or a lid therefore may have two axially spaced snap beads of 
different sizes, the lower bead giving less resistance to opening and 
closing. 
The invention further provides a container as hereinbefore defined wherein 
said rim portion is inwardly concave and has been folded inwards and is 
held in its inwards position by forces caused by folding and/or, 
particularly where the rim portion is straight, e.g. in a square 
container, wherein said rim portion has been folded inwardly and is held 
in its inwards position by glueing, welding and/or a snap action.

In the description of the different embodiments, the same reference 
numerals will be used for similar parts. The container of each embodiment 
is formed with a base 1a, a side wall 1b, a rim portion 2 and a hinge 
portion 3 all moulded in one piece from plastics. As shown, the container 
is of circular cross-section, but other cross-sections may be used. 
Preferably, the plastics is polypropylene but other flexible, resilient 
plastics such as is used for moulded containers may be employed. The hinge 
portion 3 is substantially thinner than the side wall 1b and the rim 
portion 2. No collapsible core is needed for injection moulding the 
container, as there is sufficient draw. 
The container of FIG. 1 is shown in its form as moulded. After moulding, 
the rim 2 is folded inwardly and downwardly in the direction of the arrows 
into the position of FIG. 2 and remains held securely in this position as 
a result of the forces caused by the folding operation. The same general 
principle is used in the other embodiments. FIG. 2 shows a lid 8 applied 
to the container. The rim portion 2 and hinge portion 3 of FIGS. 1 and 2 
extend continuously for the whole way round the container. 
The container of FIG. 3 has a plurality of rim portions 2 in the form of 
segments 4 spaced apart round the container. The right-hand side of FIG. 3 
shows a segment 4 in its position as moulded while the left-hand side 
shows a segment 4 in folded position. The inside of the side wall 1 is 
formed with an annular recess having an upwardly directed face 5 on which 
bears a lid 8 which, in the simplest form, may consist of a disc of 
cardboard. The lid is applied before folding in the segments 4 which, when 
folded in, act as a lock for the lid. 
The container of FIG. 4 is similar in construction to that of FIG. 3 and 
similarly illustrated, but the rim portion 2 is continuous and, when 
folded in as shown on the left of the Figure, rests on the face 5 to avoid 
any risk of the hinge breaking when subsequently lidding the container. 
FIGS. 5 and 6 show a double-hinged rim portion in the "as-moulded" position 
and the inwardly-folded position respectively. 
FIGS. 7 and 8 show, in the "as-moulded" position and the inwardly-folded 
position respectively, an embodiment in which the hinge portion 3 is 
protected from damage by being disposed below the top of the container. A 
recess and supporting face are provided, as in FIG. 4, to relieve load on 
the hinge. The rim portion 2 also has an extension which is generally 
L-shaped in section and of which the extremity bears against the inside of 
the side wall 1b as shown in FIG. 8 to reduce risk of the folded rim 
portion becoming wavy. 
FIG. 9 shows an embodiment in the "as-moulded" position having 
complementary axially-extending ribs 6 on the rim portion 2 and the inside 
of the side wall 1b. When the rim portion is folded inwardly, the ribs 
mesh to increase the stiffness of the container by preventing relative 
movement of the rim portion and side wall. 
FIG. 10 shows an embodiment in the inwardly-folded position having a rim 
portion 2 with one or more upwardly-projecting projections or ribs 7 which 
co-operate with a corresponding projection or projections on the lid 8 to 
prevent the lid from penetrating too far into the container. 
FIGS. 11 and 12 show an embodiment of container with lid in positions 
respectively before and after application. As shown in FIG. 12, when the 
lid 8 has been applied the lid and the rim portion 2 engage each other 
along a sealing line 9 and a bearing line 10. The distance between the two 
lines on the rim portion is greater than the corresponding distance on the 
lid before application. The lid has a peripheral flange which is inclined 
down at an angle .alpha. before application. On application, the 
resilience of the lid material allows the flange to distort upwards to 
that the lid can be closed and causes the closed lid to be held in tension 
between the sealing line and the bearing line. 
The container of FIGS. 13-15 has a lid 8 with a recess 11 and a hand lever 
12 for opening. A screw-driver or like tool can be inserted in the recess 
11 and twisted to open the lid. 
FIGS. 16 and 17 show a container with a pilfer-evident closure. A lid 8 is 
applied to the container and then the rim portion 2 is folded inwardly to 
snap over a ledge on top of the lid. In order to remove the lid, it is 
necessary to break part of the hinge portion 3 and peel off the rim 
portion. 
FIGS. 18 and 19 show a container having a lid incorporating two snap beads 
13. The lower bead protrudes at d for a smaller distance than the upper 
bead at D and therefore has a softer action. When the lid is pressed down 
so that only the lower bead is engaged, it can be easily removed by a 
thumb-up action. When the lid is pressed right down so that the upper bead 
is engaged, more strength or a tool is required to remove the lid. By 
choosing suitable dimensions, children would be able to open the lid only 
if the lower bead is engaged. The arrangement might also provide a useful 
safeguard in containers for drugs and dangerous products. The arrangement 
also provides an easyopening user position and a secure transport 
position. 
The embodiments shown in the drawings have circular tops and have been 
described as relying on forces caused by the inwards folding of the rim 
portion or portions to hold the latter in the inwards position. In other 
embodiments, the rim portion or portions may additionally or alternatively 
be held in the inwards position by securing means such as glueing, welding 
and/or a snap action. Such securing means may be necessary where the rim 
portion is straight, as in a container with a rectangular top.