WO2012141661A2

WO2012141661A2 - Sealing and locking means for plastic containers and lids, and to containers using such locking means

Info

Publication number: WO2012141661A2
Application number: PCT/TH2011/000008
Authority: WO
Inventors: Glenn Norman Tyler; Prajak Chiradejnant
Original assignee: Poranunt Co., Ltd.
Priority date: 2011-04-12
Filing date: 2011-04-12
Publication date: 2012-10-18
Also published as: WO2012141661A3; AU2011365704A1; CN103620047A

Abstract

A plastic container (10) and removable interlocking lid (12) forming in combination a container assembly is disclosed. In cross-sectional view, external wall (20) of the container at its rim section has a tongue (22) extending upwards and terminates in a inward directed lip (28). The lid (12) has a downwardly extending annular skirt (34) connected to a side wall panel (36) by a bridging strip (38). An annular groove (40) connected to terminal end of the skirt (34) by an annular connecting strip (42) and is foldable towards the annular skirt and abutable against the lip (28) when the lid is assembled with the container.

Description

Sealing and locking means for plastic containers and lids, and to containers using such locking means

FIELD OF INVENTION

The present invention relates to locking means for plastic containers and lids. More particularly, the present invention relates to improvements with regard to the ultimate engagement of plastic containers and lids. Yet more particularly the present invention relates to safe, secure and tamper evident fitting of plastic wide mouth containers and lids using such locking means.

BACKGROUND OF INVENTION

There are many examples of plastic industrial containers sold worldwide to manufacturers, and which are provided as wide mouthed straight or tapered walled containers. Consumers of such containers come from different market sectors, such as food and beverages, paints and chemicals, lube oils and greases, industrial and domestic detergents and manufacturers of other solid or powdery or flow able substances.

Manufacturers and consumers are now demanding containers that meet standards such as, as lower raw material content, more attractive shelf presentation, absolute tamper evidence, more robust impact performance, ergonomic ease and safer opening and closing the lid, and resealability after initial opening and usage. It is imperative that the container must perform the following functions from the time the lid is applied onto the container body up to until the final end use by an ultimate consumer: i. From the initial application / engagement of the lid onto the container, the container and lid assembly must pass, or depending on a particular national or regional market, exceed written impact performances as specified in the UN standards for the packaging of emulsion based fluids categories Group 1, Group 2 and Group 3. ii. After initial opening there must be permanent exterior physical signs of lid removal from the container body and to meet consumer demands regarding tamper evident security. iii. The lid should then be capable of being reapplied to the container body to form a tight leak proof seal, particularly with regard to the use of such containers and during paint tinting and mixing.

In large volume plastic containers of the type referred to herein for containing paints, the lid is often provided with a plurality of vertical ribs on the underside circumferential edge to strengthen the connection of central plate of the lid with the terminal flange or skirt portion of the lid. However the plurality of ribs creates compartments where liquid paint tends to attach. Upon drying, the dried paint skins drop into the body of paint containers. Therefore, there is a need to provide a lid where top load stacking strength integrity is not compromised but which solves the problem of dried paint skins dropping from the lid onto the packaged body of paint.

Some prior art examples of wide mouthed plastic containers and cooperating lids having locking and sealing arrangements may be found in US Patent Nos. 4,512,494; and 4,314,651.

Although the various inventions of the plastic containers and lids disclosed in prior art may function satisfactorily for their intended purposes, there is a need for plastic container and lid assemblies which provide leak proof, tamper evident and superior locking engagement and that meet particular global market and end user demands. After many attempts by producers of such known prior art examples to comply with global market, demands, it is clear that the prior art locking methods used to engage the container body and lid are inferior in respect of certain market performance requirements and demands.

Generally in the global market, more demands are made with regards to better absolute tamper evidence and higher drop / impact performances, whilst retaining a lightweight packaging design with favourable aesthetic features. These criteria must be met despite manufacturing containers adopting thinner wall sectioned plastics profiles.

It has been noted that most of the above mentioned prior art container assemblies fail in one or more of the market requirements. Therefore there is a need for such a container that can fulfil market performance demands.

There is a need to provide a novel a multi-purpose wide mouthed plastic containers and lids which ensure an improved engagement between the plastic containers and lids as well as provide absolute tamper evidence.

There is another need to provide plastic containers and closures that are easily closed into their final and ultimate locking position by application of small amount of pressure in the range of hand pressure and preferably without the use of tools or with use of simple hand tools. The opening of such containers and lids should be affected by the ready hand tools such as screw drivers, wedges, or any rigid elongate member or by using one's hand.

There is yet another need to provide plastic containers and lids locking system that can withstand physical impact performance demands and criteria, over and above those achieved by known prior art inventions, as well as those requirements put forward by the United Nations (UN) Code for the transportation of Dangerous Goods, JIS Standard, American Motor Freight Standards and German DIN Standards.

There is a need to provide plastic containers and lids wherein the sealing means is not compromised, when the filled container is handled in a rough manner from point of manufacture, transportation, storage and ultimate use at site of consumer. This is especially so in less industrialised countries. Performance requirements in said less industrialized countries are as follows and for example when testing 5 US Gallon plastic containers:

There is a need for plastic containers containing paint, oil, water, powdery or flow-able materials that satisfy all of the above performance criteria.

SUMMARY OF THE INVENTION The invention discloses a plastic container and removable interlocking lid forming in combination a container assembly. The container at its rim consists of an extended wall continuous with wall body of the container with a tongue extending upwards from external side of the annular wall and terminating in a inward directed lip. The interlocking lid consists of a side wall panel integrally connected to central plate of the lid, with a downwardly extending annular skirt connected to the side wall panel by a bridging strip and an annular groove. The annular grove is connected to terminal end of the annular skirt by an annular connecting strip and is foldable towards the annular skirt and abutable against the lip when the lid is assembled with the container. Further the spatial distance of opening formed by the lip and the extended annular wall is marginally smaller than the combined thickness of the groove and annular skirt folded together. The thickness of the extended annular wall is marginally larger than the distance between the annular skirt and the side wall of the annular channel so as to be tight fitting when lid is assembled over the container. In another aspect, a series of spaced apart ribs are provided to connect the tongue and the extended annular wall. To enable the placement in alignment of one container assembly on top of another, a border rib is provided on upper side of the bridging strip which is configured to receive a base chime panel of another identical container assembly. To prevent a continuous uninterrupted transfer of lateral force along the circumferential edge of the lid, there is provided at least one notch along the circumference of the annular groove.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the present invention should become apparent form the ensuing description of preferred embodiments when taken in conjunction with the accompanying drawings with the reference numerals indicating corresponding parts throughout in which:-

Fig. 1 is a perspective view of the assembled container and lid wherein the lid is in a closed engaged position.

Fig. 2 is a sectional elevation view of the container.

Fig. 3 is a plan view of the lid.

Fig. 4 is an exploded sectional view of a container rim in-volute annular tongue and lip. Fig. 5 is an exploded sectional view of the lid locking profile.

Fig. 5a is an exploded sectional view of the container and lid in its first locating position and before physical engagement.

Fig. 5b is an exploded sectional view of the container and lid and during its initial engagement.

Fig. 5 c is an exploded sectional view of the container and lid and during its secondary engagement.

Fig. 5d is an exploded sectional view of the container and lid in its final locked and sealed engagement position.

Fig. 6 is a partial cross-sectional view of the lid where the border rib is coplanar with the annular member of the lid. Fig. 7 is a partial cross-sectional view of the lid where the central plate is at same level as the bridging rib.

Fig. 8 is a partial cross-sectional view of the lid where the central plate is integrally connected to the side wall of the annular channel, without a channel in the lid.

Fig. 9a - 9d is sequence drawings of engagement of another lid and rib structure profile.

Fig. 10a - lOd is sequence drawings of engagement of another lid and rib structure profile.

Fig. 11 side perspective view of a lid with connecting ribs on the upper side of the lid.

Fig. 12 is a perspective view of the lid shown in Fig 11.

Fig. 13 is a perspective view of a opening area of the container.

Fig.14 is a perspective view of a container body with a pivotal region for removal of the lid.

Fig. 15 is a side view of the container body shown in Fig. 14.

Fig. 16 is a perspective view showing a wedge (a tip of a screw driver) is a pivotal position in relation to the lid.

Fig. 17 is an exploded sectional view of the container and lid in a locking position where the annular connecting strip has three pivotal points.

Fig. 18 and 19 are exploded sectional views of the container and lid in a locking position where the annular connecting strip has a plurality of pivotal points.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A preferred embodiment in the form of a pail and a lid assembly is described. Referring now to Fig 1 there is shown an illustration of a plastic injection moulded cylindrical container comprising a pail body (10) and a lid (12) configured to have an internal volume of approximately 25 litres or less. The pail body is generally a uniform cylindrical body, but preferably with marginally wider mouth region as compared to base region. This configuration facilitates stacking of one container on top of another identical sized container. The pail (10) includes a base chime panel (14) at its bottom base. A bottom panel (15) is profiled in a marginally concave manner to overcome deformation / bulging effect when hot contents, such as, paint or oil (at approximately 60°c) are introduced into the pail (10). The pail base panel (15) thus configured in design, profile and construction ensures that it does not sag below profile edge when the pail is filled with high density matter or hot fluids or other flowable matter.

Referring now to Fig. 4, there is shown an integral annular rim structure (16) which circumferentially extends around upper open mouth region of the pail (10). The rim structure (16) includes an extended annular wall (18) of the pail of the first part. The extended annular wall is integrally continuous with annular wall (20) of the pail (10). Marginally below the edge of the extended annular wall (18) is an upwardly extending continuous tongue (22). The tongue (22) is integrally connected to the extended annular wall (18) and the wall (20) of the pail by a generally U-shaped connecting wall (24). The U-shaped connecting wall (24) provides stronger and more resilient connector between the tongue (22) and the wall (20) as compared to V-shaped connecting wall. The space thus formed by the tongue (22), the extended annular wall (18) and the connecting wall (24) acts a trough or channel (26) to receive the lid. The tongue (22) extends upwards substantially parallel to the extended annular wall (18) and terminates in a radially inward projecting continuous lip (28). Preferably the tongue (22) extends upwards in converging relation to the extended annular wall (18). The lip (28) is approximately 90° in relation to the planar axis of the tongue (22), but preferably at an angle 90° or below up to 85°. Further details of the tongue (22) will be described later. Optionally to provide additional strength of connection between the extended annular wall (18) and the tongue (22) there are provided a plurality of ribs (27) connecting the annular wall (18) and the tongue (22) (see Fig. 6, 7, and 8). The ribs (27) also prevent the radial folding out of the tongue (22) when the lid (12) is placed in position on the pail. The ribs provide for greater stability of the lid - rim structure locking means. The tongue (22) can preferably extend downwards to provide an annular skirt (23) circumferentially surrounding the pail. The entire pail including the rib portion (16) is injection moulded with a suitable plastic material that provides good resilience and strength eg. Co-polymer Polypropylene. Referring to Fig 5, there is illustrated a cut-out sectional view of lid (12) in an equilibrium state before being engaged with the pail, and change in configuration whilst in use. The lid (12) is circular in shape with a central plate (32). An annular skirt (34) external to the central plate (32) is spaced apart from side wall (36). The annular skirt (34) is connected to the side wall (36) by means of a bridging strip (38). The bridging strip (38) also serves as a receiving platform for the base annular chime (14) of the pail if necessary.

The annular skirt (34) extends downwards and is integrally connected to an annular lip (40) by means of an annular connecting strip (42). Preferably the annular lip (40) is positioned at an angle of approximately 45° to the annular skirt (34) in its equilibrium position, (see Fig. 5). The annular lip (40) is configured to abut against the under surface of lip (28). (see Fig. 5d). The lower terminal end portion of the annular skirt (34) is tapered in cross-section (see Fig. 5). The annular lip (40) is rotatable or foldable about the connecting strip (42). When the annular lip is folded against the annular skirt (34) the combined thickness of the annular skirt and the terminal end of the annular lip (40) is only marginally larger then the mouth opening (44) in the rim-structure. This allows a tight fitting introduction of the lid onto the mouth opening of the rim-structure. At least one notch (or void) (46) is provided at a plurality of points along the annular skirt (34). Each notch (46) is a void wherein a small portion of the annular skirt (34), annular lip (40), tongue (22) and lip (28) is omitted. Thus the notch is a break or void along the continuous locking means (see Fig. 3). It is preferable a plurality of notches, preferably eight notches (46), is provided equidistant from each other along the peripheral edge of the annular lip (40). When a container with contents inside is dropped on its side, or when lateral forces are applied onto the side of the container, it is necessary that the impact forces do not completely disengage the locking means. The brunt of the impact is absorbed at the direct point of impact. At the most two notches will be directly affected by the impact. But the transmission of the lateral force all along the annular lip (40) and continuous lip (28) locking means is interrupted by the presence of the plurality of notches along the rim structure. The impact resonance due to the applied lateral forces stops at the nearest end point of the locking means portion and is not transmitted onto the adjoining locking means portions. The notch prevents or reduces the continuous uninterrupted transmission of lateral forces along the annular groove. The lid is preferably made of the same material as the pail.

In another aspect, there is provided at least one but preferably at least eight equally spaced apart lid support ribs (35) on the underside of an outer skirt (37) of the lid (12). The outer skirt (37) of the lid extends radially outwards and downwards from the bridging rib (38) of the lid. The lid support rib (35) includes a notch (39) which is dimensioned and configured to engage with the continuous lip (28) of the pail body (10).

In embodiments where there is no outer skirt, as for example, in the embodiment illustrated in Fig. 9, the lid support rib (35) on the lower external side of the tongue (34).

The workings of the pail and the lid and other features not described so far will be described now. The lid (12) is first positioned over the pail (10) (Figs 5, 9, 10). The annular skirt (34) of the lid is slid over the external side of the extended annular wall (18) of the pail. The annular skirt (34) is of a diameter marginally smaller than external diameter of the annular wall (18) of the pail. The annular skirt (34) is urged towards the connecting wall (24) of the pail. The annular lip (40) is forced rotatably towards the annular skirt (34). (see Figs. 5, 9, 10) In an alternate manner it can be said the annular lip is folded towards the annular skirt about the connecting strip (42) (see Figs. 5, 9, 10). The folded annular lip (40) once forced into the trough (26) of the lid, now folds backwards to substantially return to its original equilibrium position. The annular lip (40) now abuts against the underside of the lip (28). (Figs. 5, 9, 10) The continuous lip engages upon the notch (39) to provide a firmer lock relationship between the lid and the pail body. This further enhances the tight fitting of the lid within the pail body as well as providing lateral hoop strength support upon the engagement of the lid and the pail body. The annular lip (40) when folded against the annular skirt (34) forms a wedge shaped structure at the terminal end (Figs. 5, 9, 10). Once the lid is placed in registration on the pail as aforesaid described, the operation is repeated across the entire peripheral edge of the lid to close the lid on the pail completely. In this position the lid is securely fitted onto the pail. An unexpected advantage of this invention is the creation of a snap fastening click sound when the lid is fitted properly onto the lid. The click sound indicates to the user that the lid is securely fitted over the pail. To close the lid, in the present embodiment, hand pressure is sufficient to engage the lid with the pail in a locking position.

The ribs (27) in the container rim, if present, prevents the tongue (28) from being partially distanced beyond original pre-determined distance between the lip (28) and the extended annular wall (18). This configuration will ensure that the lid and pail remains in a tight fitting manner when in use. The edge of the extended annular wall (18) is dimensioned to and to preferably contact with underside of the bridging rib (38) when fully assembled (see Figs. 5, 9, 10). The thickness of the extended annular wall (18) is equal to or marginally larger then the distance apart between the annular skirt (34) and the side wall of the side wall (36). This configuration gives a tight fitting closure of the lid over the pail. It also prevents leakage of the contents of the pail to the outside through lid-pail locking means (see Figs. 5d, 6d, lOd).

The rim structure (16) includes at least one but preferably four notch (52) regions to facilitate opening of the lid from the pail (see Fig. 13). A small section of the tongue (22) is cut or weakened along the vertical axis and is weakened along horizontal circumferential line (54) across the external surface of the tongue (see Figs. 14, 15). Preferably, but not necessarily, the tongue can be weakened along a line adjacent or along the connecting wall (24) of the rib. The external portion of the notch is preferably ribbed to facilitate easy manual handling of notch (52).

To open the lid from the sealed position from the pail, the notch is moved externally and downwards from the central axis of the pail. As the notch is cut or weakened along the vertical axis and is weakened along the horizontal circumferential line, it is easily displaced from its equilibrium position. Thereafter a prying tool (50) such as a screw driver, is introduced into the gap formed by the external side of the tongue (34) and the inner side of the tongue (22). Using the prying tool, the lid portion at the side can be lifted up to disengage it from the tongue. The process can be repeated at the other remaining notch regions (52). The lid can thereafter be disengaged from the pail by applying manual force. Some variations to embodiment described earlier will be described now. In the present embodiment there is an annular border rib (48) located at inner side of the bridging rib (38) (see Figs. 6, 7, 8). The base chime panel (14) would be positioned outside the peripheral edge of the border rib (48). In another aspect the border rib (48) can also be positioned at the opposite edge, ie. coplanar with the annular skirt (34) (see Fig. 7). In the embodiment described earlier (Fig. 5) the central plate (32) of the lid is at mid portion level of the side wall (36) and perpendicular to it. It will be appreciated that the central plate (32) can be at a higher level (see Fig. 9) without jeopardising the operations of the lid-paid closure mechanism. Yet in another aspect, the channel (30) formed between the side wall (36) and the central plate (32) can be eliminated. In this embodiment the central plate (32) of the lid is integrally connected side wall (36) (see Fig 10). This configuration also eliminates the unwanted gathering of dust or liquids in the channel (30) in stored containers as in the earlier referred embodiments. It will be apparent to a person skilled in the art to arrive at different configurations of the lid without departing from the principles described.

Fig. 9a - 9d, 10a - lOd illustrate two different embodiments and the manner of fitting the lid onto the pail. In Fig. 9a - 9d, it will be observed that the continuous lip (28) is not perpendicular or acute angular position in relation to the tongue (22) but is greater than 90°.

Referring to Fig 11, 12, there is shown a lid with a lock mechanism as described before, but where a plurality of ribs (58) are provided connecting the central plate of the lid (32) to the side wall (36). Groups of ribs can be provided equidistant from each other. A lid (60) hinged joined at the bridging strip (38) is provided to enclose the group of ribs. The space between groups of ribs is provided with an integral flap (62) connecting the bridging strip (38) and the central plate (32) of the lid.

To prevent direct lateral impact on the lid and rim structure, an annular bumper bar (63) can be provided below and adjacent to rim structure (16). The bumper bar extends laterally marginally beyond the tongue (22) of the rim structure (see Figs. 10a - lOd). In embodiments where there is no notch (52) in the rim structure, to open the lid from its sealed position from the pail, a screw driver or a prying tool (50) is needed. Sharp end of the screw driver is introduced into the interface between the lip (28) and the annular skirt (34) by the application of appropriate force. The screw driver is rotated radially downwards, thereby forcing the annular skirt (34) upwards at the region where the screw driver is used. The procedure is repeatedly at one or more adjacent position (s). The lid can then be easily detached from the pail.

To reclose the lid over the pail, lid is placed in registration of the rim structure and downward pressure is applied all along the circumferential edge until the locking mechanism is fully engaged. As the lid and the pail are made of flexible plastics material, there is no permanent deformation of the various components in the lid and pail, unlike similar locking means in metallic paint containers. In the alternative embodiment, where notches (52) are provided the separation of the tongue portion at the notch is evidence of tampering.

To improve the aesthetics of the pail and lid assembly, an annular curtain (56) can be advantageously provided. The annular curtain (56) extends radially downwards and outwards from the bridging strip (38) of the lid (12). The annular curtain (56) not only improves the eye appeal of the container and lid assembly, but also reduces the collection of dust or dirt in interface region between the tongue (22) and the annular skirt (34).

The introduction of a screw driver or a prying tool between the interface as afore described, leaves a "scar" at the area - the edge of the lip (28), the annular groove (40) and the annular member (34) will be permanently damaged, although not to the extent of jeopardising the resealability of the lid and pail. The scar will be evidence of attempted opening or opening of the lid. In another aspect of the invention, the annular connecting strip (42) of the lid, connecting the annular skirt (34) and the annular lip (40) can advantageously consists of a plurality of folds (64) (see Figs 17, 18, 19). The plurality of folds (64) enables better and firmer engagement of the annular lip (40) against the tongue (22) and the lip (28). The introduction of the lid onto the container is as per description of the embodiments described earlier in this description.

In container with an internal volume of 25 litres or less, the general wall sections (32), side wall of the annular channel (36), annular skirt (34), generally other sections of the lid are of cross-sectional thickness between 1.3 - 1.5 mm. The general wall sections of the container, such as the extended annular wall (18), annular skirt of the tongue (23), are of cross-sectional thickness of 1.5 - 1.8 mm. The tongue (22) section of the container is preferably thinner than the section of the annular skirt of the tongue (23). The tongue (22) is of 0.9 - 1.1 mm on cross-section thickness wherelse the cross- section thickness of the annular skirt (34) is 1.3 - 1.5 mm. The thinner cross-sections of the tongue allows easier closing without distortion and stress build up of the assembled lid and container. The folds (64) in the annular connecting strip (42) are of 0.25 - 0.30 mm thickness in cross-section.

The pail and the lid and the various configurations and embodiments described herein can be manufactured by plastics injection moulding method, which is well known in plastic injection moulding industry. The malleability and the resilient nature of plastics used enable the engagement, removal of the lid onto and from the container respectively. The development and fine tuning of injection moulding equipment enables the manufacturing of the embodiments described herein.

Claims

1. A plastics container and removable interlocking lid forming in combination a container assembly: a) wherein the container at its rim consists of an extended annular wall (18) continuous with wall body (20) of the container with a tongue (22) extending upwards from external side of the annular wall (18) and terminating in a inward directed lip (28) and wherein the annular wall and the tongue are connected by a connecting wall (24); b) wherein the interlocking lid consists of a side wall panel (36) integrally connected to central plate (32) of the lid with a downwardly extending annular skirt (34) connected to the side wall panel by a bridging strip (38) and an annular lip (40) connected to terminal end of the annular skirt (34) by an annular connecting strip (42) and foldable towards the annular skirt and abutable against the lip (28) when the lid is assembled with the container; c) wherein the spatial distance of opening (44) formed by the lip (28) and the extended annular wall (18) is marginally smaller than the combined thickness of the annular lip (40) and annular skirt (34) folded together; and d) wherein the thickness of the extended annular wall (18) is marginally larger than the distance between the annular skirt (34) and the side wall (36) so as to be tight fitting when lid is assembled over the container.

2. A plastic container and removable interlocking lid as claimed in claim 1 wherein an annular outer skirt (37) extends radially outwards and downwards from the bridging rib (38).

3. A plastic container and removable interlocking lid as claimed in claim 1 wherein at least one vertically extending lid support rib (35) with a notch (39) is provided on the external surface of the annular skirt (34), said notch (39) being dimensioned and configured to engage with the continuous lip (28).

4. A plastic container and removable interlocking lid as claimed in claim 1, wherein the inward directed lip (28) is inclined at an angle of approximately 90 degrees against the tongue (22).

5. A plastic container and removable interlocking lid as claimed in claim 1, wherein the annular lip (40) is inclined at an angle of approximately 45° against the annular skirt (34) when in an equilibrium position.

6. A plastic container and removable interlocking lid as claimed in claim 1 wherein the annular connecting strip (42) consists of a plurality of folds (64).

7. A plastic container and removable interlocking lid as claimed in claim 1 wherein a series of spaced apart ribs (27) are provided to connect the tongue (28) and the extended annular wall (18).

8. A plastic container and removable interlocking lid as claimed in claim 1 wherein a border rib (48) is provided on upper side of the bridging strip (38) and which bridging strip (38) is configured to receive above it a base chime panel (14) of another identical container assembly.

9. A plastic container and removable interlocking lid as claimed in claim 1 wherein at least one notch (46) is provided along circumference of the lid to prevent uninterrupted transfer of force from one part of the lid to another along circumference edge of the lid (12) wherein the notch consists of portions of the annular skirt (34), continuous lip (40), and/or bridging strip (38) removed.

10. A removable interlocking lid removeably securable to a plastics container consisting of a central plate and a side wall wherein groups of ribs (58) on the exposed side of the lid connecting the central plate (32) of the lid and the side wall (36) to provide strength of connection between the central plate and the side wall.

11. A removable interlocking lid as claimed in claim 8 wherein a hinged cover (60) is provided to conceal the ribs, and wherein the cover in hinged joined at a bridging strip (38) connecting two annular flanges (34, 36).

12. A plastic container and removable interlocking lid as claimed in claim 1 wherein a tamper evident flap is provided at least one point along the circumferential surface of the tongue (22) wherein the flap includes a weakened or cut vertical edges along the tongue (22) and a weakened horizontal base (54) such that the flap can be rotatably moved away from container.

13. A plastic container and removable interlocking lid as claimed in claim 1 wherein the lid is separable from the container by means of a prying tool (50) introducible underneath the annular lip (40) and the annular lip is capable of being spaced apart from the lip (28).

14. A plastic container and removable interlocking lid as in claim 11 and 12 wherein the prying tool is capable of being introducible underneath the annular lip (40) after the flap is rotated away from the container.

15. A plastic container and removable interlocking lid as claimed in claim 1 wherein cross-sectional thickness of the central plate of the lid (32) is between 1.3 - 1.5 mm, and the cross-sectional thickness of the annular connecting strip (42) is between 0.25 - 0.30 mm.

16. A plastic container and removable interlocking lid as claimed in claim 1 wherein the cross-sectional thickness of the tongue (22) is smaller than the cross-sectional thickness of the wall sections (18).

17. A plastic container and removable interlocking lid as claimed in claim 16, wherein the cross-sectional thickness of the tongue is 0.9 - 1.1 mm and the cross-sectional thickness of wall section is 1.5 - 1.8 mm.