WO2000046118A1

WO2000046118A1 - Receptacle with inwardly projecting rim and lid

Info

Publication number: WO2000046118A1
Application number: PCT/GB2000/000283
Authority: WO
Inventors: Charles Jonathan Britton
Original assignee: Pcc Technologies Plc
Priority date: 1999-02-02
Filing date: 2000-02-02
Publication date: 2000-08-10
Also published as: ZA200107258B; GB9902244D0; AU2304900A; IL144704A0; IL144704A

Abstract

A container of the paint tin kind has a receptacle (1) with a lid (6) which press fits to the rim (2) of the receptacle. The periphery (9) of the lid (6) undulates outwardly from an inner skirt (10) with a downwardly-open channel (13, 14), an upwardly-open channel (16), and a lateral flange (18). The rim (2) is generally of box section, formed by blow moulding, with a flange (21) providing the inner limb of an upwardly-open channel (16). On engagement, an outward projection (11) of the skirt (10) snaps under the flange (21), for the main retention of the lid, the flange (21) seats in the channel (13, 14), and the portion that forms the channel (16) seats in the channel (22), the main sealing being at opposite sides of this channel (22). The box section is reinforced at intervals by radial ribs (31) whose inner extremities (34) ensure dimensional stability at the base (32, 36) of the flange (21) for proper engagement by the skirt projection (11). Bale lugs (40) can be part of the injection moulded receptacle rim, to be largely assimilated with the wall by the blow moulding.

Description

RECEPTACLE WITH INWARDLY PROJECTING RIM AND LID

This invention relates to plastics containers. There has been described in WO 97/19801 a method of forming a plastics container with a rim similar to that of a conventional paint tin by blow moulding. This has proved very effective. However as with most innovations, there can generally be improvement, and this invention is aimed at providing an improved sealing arrangement for the lid and at strengthening the rim structure. According to the present invention there is provided a container comprising a receptacle and lid, the receptacle having a rim projecting inwardly from adjacent walling and the lid being a press fit into the rim, wherein the rim of the receptacle has an upstanding first flange forming the inner limb of an upwardly open channel from whose outer limb laterally extends a second flange, and wherein the periphery of the lid has an inner portion that closely co-operates with the inside of the first flange, an intermediate portion separated from the first portion by a downwardly-open channel which receives the first flange while the intermediate portion seats sealingly within the upwardly open channel, and an outer portion that overlies the second flange .

Preferably there will be a third flange upstanding from the periphery of the second flange. With the lid fitted to the receptacle a gap will be left between the outer edge of said outer portion and this third flange and a space between the underside of said outer portion and the second flange. The third flange will provide a fulcrum for an implement such as a screwdriver to be inserted for levering off the lid.

When the intermediate portion is seated m the upwardly open channel there will generally be sealing to both the inner and outer limbs of the channel. Also, at least one pair of the co-operating sides of the upwardly open channel and the intermediate portion of the periphery of the lid will advantageously have a rib on one side and a complementary groove m the other which will have snap engagement when the sealing is effected. Preferably, the inner portion of the lid has a projection on its outer side to snap engage under the rim as sealing is effected. This will be the mam agency for retaining the lid, and although it might contribute some sealing, the main sealing zone will be elsewhere.

The intermediate portion of the rim of the lid may be formed as an upwardly-open channel. This will allow it to be transversely compressed as it is urged into the upwardly- open channel of the receptacle rim, enhancing the seal.

The upper edge portion of the first flange preferably seats snugly m the base of the downwardly open channel. While not being the primary seal, this arrangement can contribute a further sealed barrier. When the receptacle is completed by blow moulding to expand a tubular or cup- shaped portion depending from the rim to form the mam body of the receptacle, the rim can be made as a box section. The expansion may commence at the base of a downward extension of the rim, and this extension is preferably reinforced by ribs extending radially inwards from the outer wall of the box section. These ribs maintain dimensional stability. A shoulder created at the bottom of the extension by the blow moulding will provide the part of the rim under which the projection on the inner portion of the lid snaps when the lid is fitted.

The under edges of the ribs can also serve as barriers to any excessive penetration of the box-section by the upper portion of the blown tubular or cup-shaped portion. Usually the ribs will span the entire box section, but that is not essential for their ma function of maintaining dimensional stability.

It is sometimes desirable to provide paint tins with handles, and these are generally simple semi-circular loops hinged to diametrically opposite points. When these are slightly below the rim, as is often the case m the USA, they are attached to bale lugs.

The receptacle outlined above can be formed with opposed bale lugs for a strap handle. Each lug may be a downward extension of the outer wall off the box section. It can be internally strengthened by a downwardly enlarged rib whose upper part performs the reinforcing operation of the ribs already referred to and around whose lower part the expanded portion wraps. The ma portion of each bale lug will be assimilated into the wall of the receptacle as the expanded portion is blown flush with its exterior surface, leaving a part projecting with which an end of the strap handle can engage.

For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the accompanying drawings, m which: Figure 1 is a vertical section of a blow moulded plastics container, comprising a receptacle and a lid, shown pre-fittmg position,

Figure 2 s a sectional detail of the rim of the lid,

Figure 3 is a sectional detail of the rim of the receptacle,

Figure 4 is an exterior view of part of the upper end of the receptacle showing a bale lug, and

Figure 5 is a vertical section on the line V-V of Figure 4. Referring to Figure 1, a receptacle 1 is of generally cylindrical form with an inset, annularly grooved rim 2 to be described m more detail below. It is stretch blow moulded by the technique described WO 97/19801 to have a base with an annular rib 3 encircling a slightly recessed central portion 4. The cylindrical side of the receptacle is formed with vertical ribs 5, the plastics being indented into the receptacle, to improve rigidity.

A lid 6 for this receptacle may be injection moulded as a generally flat disc 7 (very slightly dished m the example shown) with an upstanding annular rib 8 near its periphery and beyond that a profiled rim 9 that co-operates with the rim 2 whose shape is best seen Figure 3.

But referring first to Figure 2 and the rim 9, at the periphery of the disc 7 there is a small step down and out to a depending skirt 10 with an annular projection 11 at its bottom edge, half arrowhead m cross-section. This forms a downwardly and outwardly facing chamfer and an upwardly facing shoulder that acts as a hook, as described below. The width of the hook may only be of the order of 1mm, to allow snap release from the mould. The skirt 10 thickens outwardly at a step near the top and provides the inner limb 12 of an inverted annular channel with a narrow base 13 and a wider mouth 14. The outer limb 15 of this channel returns to about the mid-height the skirt 10 and also provides the inner limb of an upwardly open channel 16. The outer limb 17 of that terminates in an outwardly projecting flange 18 level with the top of the base 13. Both channels are slightly flared and on the inside of the limb 15, near the top, and on the outside of the limb 17, towards the bottom, there are shallow grooves 19 and 20 respectively. The rim 8 fits sealmgly to the inner part of the rim 2 and its flange 18 overhangs a space m the rim 2 which enables the lid 6 to be levered off using the extreme outer top edge of the rim 2 as a fulcrum. It is thus a container of the type commonly known as a paint tin.

Referring to Figure 3, the rim 2 is of more complex, undulating shape than the conventional paint tin rim, offering two and possibly three or even four annular sealing zones and strong enough to sustain the stresses to which such a rim may be subjected.

In cross section, the rim 2 has, from the inside, an upstanding flange 21 defining the inside of a U-shaped channel 22 whose outer side 23 is lower than the flange 21. A horizontal flange 24 projects outwardly from the side 23 from just below the latter' s smoothly rounded top 25 and a skirt 26 depends from its outer edge. At the top of the skirt 26 there is a shallow external annular groove 27 used in holding the preform during moulding. At the outer top corner of the flange 24 there is an outset and upstanding further flange 28 whose rounded top is just higher than the top of the flange 21.

The flange 21 has a slight inward taper towards the top, and the channel 22 is slightly flared. On the outside of the flange 21, near its top, and on the inside of the side 23, also near its top, there are small annular ribs 29 and 30 respectively. They are small enough for the rim 2 to be snap-extracted without damage from the single mould part that forms the upper profile.

It will be understood that the ribs 29 and 30 could be on the lid and the grooves 19 and 20 on the receptacle. At regular intervals around the rim 2 there are slim ribs 31 in planes radial to the axis of the receptacle. They are shown in cross hatching to distinguish them from the hollow space which occupies much of the rim and from the rest of the rim with which they are integrally moulded. The ribs 31 are generally of polygonal form, with two edges at right angles joined by the integral moulding respectively to the underside of the flange 24 and the inside of the skirt 26. Ignoring a small indent into the rounded top 25, a third edge is concave, follows and joins to the side 23, and extends under the channel 22 to terminate at a short downward extension 32 of the side 21. Before blow moulding, the extension 32 continues down smoothly into the tube or cup- like structure 33 that is expanded from the broken line position to form the body of the receptacle. The under edge of each rib 31 is straight and extends inwardly from just above the bottom of the skirt 26 to the bottom of the extension 32. Initially, this edge is free, but the rib 31 provides a fmger 34 which abuts the outside of the extension 32.

The rim 2 is shown in Figure 3 after completion of the receptacle 1 where the tubular or cup-like part 33 of the preform has been urged by the blowing upwardly and outwardly to meet and weld to the lower edge of the skirt 26. Beyond the outer shoulder 35 thus created, and below the skirt 26, the plastics material presses against the inside of the cylindrical mould cavity into which that skirt snugly fits. There is therefore a substantially smooth exterior transition between the skirt 26 and the wall of the container. An inner shoulder 36 is also created at the junction of the extension 32 and the outwardly turned uppermost section 37 of the expanded structure 33. This section 37 comes up against the lower edges of the ribs 31, one minor function of which is to contribute some reinforcement to the rim. Another, more important one is to arrest the upward expansion of the section 37. Without these ribs, or with smaller ones not extending down so far, as has previously been proposed, the hot malleable plastics can be blown upwardly too far towards the flange 24 thus failing to create a good box-section, which is the principal source of strength of the rim 2. An even more important function of the ribs 31 is to give dimensional stability to the extension 32. When the structure 33 below it is hot enough to be blow-moulded, that extension is itself inevitably quite hot, and malleable to a certain extent. The blowing can deform it. But the presence of the fingers 34 of the ribs 31 prevents this, at least locally. The number of ribs 31 required will vary with the size of the container, but it is reckoned that eight will generally suffice for small containers, say of half-litre capacity, while sixteen might be advisable for large, five-litre containers.

When the lid 6 is fitted, the skirt 10 locates mside the flange 21, the flange 21 enters the channel 13, 14, and the portion forming the channel 16 enters the channel 22. The channel shape allows the inner and outer limbs 15 and 17 to be squeezed together slightly, facilitating the ribs 29 and 30 snapping into the grooves 19 and 20. Simultaneously the projection 11 reaches the shoulder 36 and its hook snap engages under that. Also at the same time, the top of the flange 21 seats m the base 13 of the inverted channel of the lid 6. The flange 18 projects towards but does not reach the flange 28, and there is space beneath it into which the tip of a screwdriver can be inserted for levering the lid free, using the top of the flange 28 as a fulcrum. This engagement gives two annular sealing zones m the regions of the ribs 29 and 30 and grooves 19 and 20, and another possible sealing zone between the top of the flange 21 and the channel base 13, although that is not necessarily relied on. There is a contribution to the retention of the lid by the ribs and grooves and the surfaces wedged together their vicinity but the mam retention is by the engagement of the projection 11 and shoulder 36. In other words, unlike any pamt tins known to Applicants the sealing and the retention of the lid are separated.

Release is unlikely to be as easy as with most pamt tm-type containers, since there are four annular zones where the lid 6 engages the rim 2. Even if one or both of the ribs 29 and 30 were omitted, which is an option, there would still be very firm lid retention.

Figures 4 and 5 show how provision may be made for fitting a strap handle. At diametrically opposite positions the skirt 26 is extended downwards as a trapezoidal bale lug 40. Towards the lower end of this there is an external, downwardly open hood 41 with an aperture 42 central of a sloping step 43. Internally, each of a pair of diametrically opposite ribs 31 s downwardly enlarged as a rib 44 to support the lug 40 by its lower part and reinforce rim 2 by its upper part, in the manner of the ribs 21. It presents its hypotenuse to the tubular or cup-like part 33. When that is blown it will engage each rib 44 and wrap it around it before pressing outwardly against the inside of the lug 40 and moulding itself around the edges of the lug to become flush with its outer surface. The lug 40 will effectively be assimilated into the wall of the receptacle, but the hood 41 will be left projecting.

One hooked end of the handle (not shown) , which may be in the form of a stiff wire semi-circle, is entered through the aperture 42 and is caught by the hood 41. The other end is likewise engaged by the corresponding bale lug.

Claims

1. A container comprising a receptacle (1) and lid (6) , the receptacle having a rim (2) projecting inwardly from adjacent walling and the lid (6) being a press fit into the rim (2) , characterised that the rim (2) of the receptacle (1) has an upstanding first flange (21) forming the inner limb of an upwardly-open channel (22) from whose outer limb (23) laterally extends a second flange (24) , and in that the periphery of the lid has an inner portion (10) that closely co-operates with the inside of the first flange

(21) , an intermediate portion (16) separated from the first portion (10) by a downwardly-open channel (14) which receives the first flange (21) while the intermediate portion (16) seats sealmgly within the upwardly open channel (22), and an outer portion (18) that overlies the second flange.

2. A container as claimed m Claim 1, characterised m that a third flange (28) is upstanding from the periphery of the second flange (24) and m that, with the lid (6) fitted to the receptacle (1) , a gap is left between the outer edge of said outer portion (18) and the third flange (28) and a space is left between the underside of said outer portion (18) and the second flange (24) .

3. A container as claimed m Claim 1 or 2, characterised in that when the intermediate portion (16) is seated the upwardly open channel (22) there is sealing to the inner and outer limbs (21, 23) of the channel (22) .

4. A container as claimed m Claim 3, characterised m that at least one pair of the co-operating sides of the upwardly open channel (22) and the intermediate portion (16) of the periphery of the lid (6) has a rib (29, 30) on one side and a complementary groove (19, 20) m the other which have snap engagement when the sealing is effected.

5. A container as claimed m any preceding claim, characterised m that the inner portion (10) of the lid has a projection (11) on its outer side to snap engage under the rim (2) as sealing is effected.

6. A container as claimed any preceding claim, characterised in that the intermediate portion (16) is formed as an upwardly-open channel.

7. A container as claimed m any preceding claim, characterised m that the upper edge portion of the first flange (21) seats snugly m the base (13) of the downwardly open channel (14) .

8. A container as claimed m any preceding claim, characterised in that the receptacle (1) is completed by blow moulding to expand a tubular or cup-shaped portion (33) depending from the rim (2) to form the mam body of the receptacle and to make the rim (2) a box section, m that the expansion commences at the base of a downward extension (32) of the rim (2) , and m that this extension is reinforced by ribs (31) extending radially inwards from the outer wall (26) of the box section.

9. A container as claimed m Claim 8, as appendant to Claim 5, characterised in that a shoulder (36) created at the bottom of the extension (32) by the blow moulding provides the part of the rim (2) under which the projection (11) snaps when the lid (6) is fitted.

10. A container as claimed in Claim 8 or 9, characterised in that the under edges of the ribs (31) serve as barriers to any excessive penetration of the box-section by the upper portion (37) of the blown tubular or cup-shaped portion (33 ) .

11. A container as claimed in Claim 8, 9 or 10, characterised in that the ribs (31) span the entire box section.

12. A container as claimed in any one of Claims 8 to 12, characterised in that the receptacle (1) is formed with opposed bale lugs (40) for a strap handle, each lug (40) being a local downward extension of the outer wall (26) of the box section and being strengthened internally by a downwardly enlarged rib (44) whose upper part performs the reinforcing function of the ribs (31) and around whose lower part the expanded portion (33) wraps.

13. A container as claimed in Claim 12, characterised in that the main portion of each bale lug (40) is assimilated into the wall of the receptacle as the expanded portion (33) is blown flush with its exterior surface, leaving a part (41) projecting with which an end of the strap handle can engage.