CA1055891A

CA1055891A - Container and closure therefor

Info

Publication number: CA1055891A
Application number: CA266,530A
Authority: CA
Inventors: Victor E. Crisci
Original assignee: Individual
Current assignee: Individual
Priority date: 1975-12-31
Filing date: 1976-11-24
Publication date: 1979-06-05
Also published as: US4004710A

Abstract

CONTAINER AND CLOSURE THEREFOR
Abstract of the Disclosure A snap-lid container, particularly in plastics material, of the pail type for fluid materials. A fluid-tight seal between the container and lid is effected by peripheral contact under pressure between a convex inner edge of the container lip and a splayed surface within a peripheral, inverted U-groove in the lid. Sealing pressure is provided by coaction between complementary sloping surfaces on the container lip and within the lid peripheral groove respectively which tends to draw the lid in a closing direction.

Description

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This invention relates to ccntainers and closures therefor and more particularly to containers manu-factured of plastics materials and adapted to hold fluids such as latex-based paints and the like.
Paint, a material which requires a strong light-weight container, traditionally is packaged in cylindrical drum-type cans fabricated ~rom sheet metal - usually tin- i~
plated steel. Due to the nature of paint9 it is necessary to have a completely fluid-tight seal between container and lid otherwise drying out of the material would occur thereby rendering it useless~ A simple circular lid having a formed peripheral edge such as to provide an interference it within the mouth of the con~ainer provides an adequate seal.
Convenience and cost con~ideration in the manu-acture of containers result in a structure which includes joined seams~ These seams are points of weakness where corrosion may begin. ~ith oil based pa;nts, this is not normally a problem but with latex base paints which include a considerable amount of water in their makeup, it can be.
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To overcome this, the seams must be specially treated to inhibit corrosion thereby adding to the cost of the contai~er.
Metal paint container bodies, again for reasons of ease of production and cost, are usually cylindrical in shape so that when empty they cannot be "nested". Packaging of empty containers, therefore, is bulky and inconvenient from . .
a handling, storing, transportation and expense point of view.
5, To overcome the disadvantages of metal containers, 5'' ~ paint containers made from plastics materials have been made.
In these constructions, in order to obtain the fluid-tight ~,.
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seal between the container and closure, an O-ring or other type of resilient seal has had to be used. Plastics con-tainers of known design rely upon such a lar~e constrictive ~orce in the closure to retain them closed ~hat the closures 5 need to be slit to enable them to be removed or ~heir re-moval is only possible by use of removal tools which render them permanently damaged.
An object of the present invention is to provide a contain~r of plastics material which avoids the need for the 10 use of a seal which is additional to the container body and closure.
According to the present inventlon, there is pro-v~ded a container comprising a container body and a closure both being of plastics material, the body havlngr an annular 15 wall de~ining an opening and a lip around t~e opening, the t lip having a sealing region surrounding the opening and a radially outwardly directed shoulder spaced axially along the wall from the sealing region, the shoulder having an abutment surface facing radially outwardly and axiall~J away 20 from the lip, and the closure having a cover portion surrounded by a U-shaped rim, the rim comprising a radially inner axlal wall, a spaced radially outer axial wall and a base interconnecting said walls which deine between them an axially facing re~ess of the rim for insertion of the lip 25 between the walls, the rim also including a sealing region at the junction of the inner wall and base, one sealin~
region being in compressively loaded and tangential engage-ment with the other region to provide substantially a point contact ~etween the regions in a cross-section along the axis 30 and along a single annular line when the lip is received ~, _ .. . . .

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within the rim, and the outer wall incorpvrating a radially inwardly projecting bead to coact with the shoulder to urge the lip towards the base of the rim and to urge the sealing regions into said engagement, the outer wall being resili- .
ently ~lexible outwardly for snap engaLgement around and release from the shoulder.
In one preferred arrangement, the rim sealing . region is an annular splayed surface at the junction of the inner wall and base and the lip sealing region is a convex - 10 edge of the lip. Alternatively, however, other shapes may be used to produce a comparable sealing effect~ For in-. stance, a convex surface may be provided ~or the rim sealing : region while a chamfered edge o~ the lip is the lip sealing region; in o~her cons~ructions bo~h sealing regions may be lS surface or edge shapes which are convex, or a convex shape may be required to ~it into a concave shape of greater radius so that single line contact is achieved.
In the closure, the bead is a relatively stiff ; :
. portion of the outer wall w~ich applies an annular con- : .
:20 stricting force to hold the wall in lts normal position.
The flared skirt acts as a lever which when urged radially outwards and upwards at a speciic circumferential pointJ
. flexes the outer wall at that point resiliently to stretch the bead to allow .it to co~mence movement around t~e lip in .. 25 a closure releasing direction. Outward levering of the ~ .
skirt circumferentially in a progressive manner from said specific point stretches the bead in corresponding fashion : -, . .
so as completely to unseat it ~rom the lip. The bead serves ,. not only as a constrictive force but because it is a region ;:` 30 o~ relatively greater stifness than the remainder of the :........................................................................ ~
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1~55891 wall, the wall tends to flex at a bend position towards the ~ base upon the application of a radially outwards force upon `~ the skirt so that the bead is pivoted from the bend - position.
In addition, the flared skirt tends towards an axially straight line relationship with the remainder of the outer wall whereby when a radially outwards force is applied to the s~irt, there is a large component of force also applied radially outwards to the remainder of the wall SQ as -to stretch it. With this construction, the skirt may ha~e a thickness no greater than the remainder o~ the wall, apart from at the bead, while being sufficiently stiff to cause ; bead removal without any undue flexing o~ the skirt itself relative to the wall towards the base. In preferred con-lS structions, the angle of the skirt i5 between 35 and 45 to ! the axial direction in its normal and unflexed state with the preferred angle being 40.
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The container body and closure provide a cheap, f easily manufactured, container which, when the two parts are ~, 20 assembled together is fluid tight and the closure will not ~,!
~ ,' ' ', easily detach itself from the container body under loads ; applied to it in an accidental manner because of the cir- -' cumferentially applied constrictive force by the bead. The : .
; sealing regio~s provide an e~ficient seal as the full com-, ~ , , 25 pressive loading action between the sealing regions acts at the single annular line of contact thus creating maximum D' ; ~ ~ .
; pressure conditions to make and retain a sealed condition.
~ An understanding o~ the invention will be gained ,~ from reading the following description taken in conjunction ", with the accompanying drawings illustrating one embodiment ... .. .
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and wherein:
FIGURE 1, is a side elevational view of a pain~
container showing the body and closure assembled and partly in section, and nested in another container shown in phantom lines;
FIGURE 2, is a cross-sectional view, on a larger scale than Figure 1, o~ portions o the assembled container and closure rim ` 10 show-lng the seal and also showing a modiication to a bail anchoring means shown in Flgure l; and FIGURE 3, is a side elevational view, on a smaller 9cale than Figure 2, of a por~ion o~ the j 15 container rim showing bail anchoring j - means.
A container comprises a container Body generally indicated at 10 in Figure 1, which is a one-piece moulding in plastics material suc~ as high density polyethylene~ ~n annular side wall 11 tapers gently at an angle of 2 to the container axis o~ symmetry rom a narrow upper end portion 12 defined by a s~ep 13 to a recessed bottom wall 14 re-. ~
inforced by an integral radial rib structure shown in part j at 15. -~25 Turning now to Figure 2. Upper end portion of side wall 11 is generally cylindrical and terminates in a ;
-; lip 16 defining a circular container opening. Generally . .
rectangular in cross-section, the lip of the container has ; a sealing region comprising a convexly radiused edge 17 at and surrounding the opening and an outer radiused edge 17a.

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~ ~ 5 5 8 9 1 The lip 16 is thicker than side wall portion 12 immediately below it whereby there is provided a radially outwardly ;~
directed shoulder 18 having a lower sur~ace 19 which slopes inwards and downwards to the container side wall at a pre-ferred angle of 38 to the vertical but which may be at any angle between 35 and 45~
A short distance below rim 16, there extends a radial flange 20 carrying at its outer peripheral edge à
dependent skirt 21 generally parallel to and spaced from lQ upper portion 12~ At the upper end of the annular recess ~; formed by the flange 20, the skirt 21 (Fig. 1) and the upper ;~
portion 12 there i9 integrally formed an intermediate annular rlb 22 and a series of eqtti-angularl~ disposed radial rlb8 such as 23. The oregoing structure impar~s a high degree j 15 of rigidity to the upper portion 12 of the container side i ~Jall particularly to the portîon including rim 16 and resists any tendency for the container body to flex at the lip under '!', the weight of contained paint when a closure has ~een remQved and the lip is held at one position.
-20 Two diametrically opposed bail anchoring means are integrally formed with the flange 20 and skirt 21. One bail anchoring means only is shown in Figures 2 and 3 at 24. The bail anchoring means may be adapted to receive a rigid common ~ wire bail 25 as shown in part in Figure 1 or a more flexible $
^- ~25 type 26 in preformed p~astics materials shown in part in Figure 2.
Each bail anchoring means 24 comprises a rectangu-~ar, open-bottomed, box-like structure. These structures may .
extend at least to the step 13 in the container side wall or `~ 30 further below as in the em~odiment wherein it prlevents the :

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~amming together of nested contalners. Outer walls 27 of the anchoring means 24 may be providecL with a s:imple hole 28 (Fig. 1) to receive bent ends o~ a rigid, common wire bail 25. An alternative arrangement in the outer walls 27 in-cludes a V-form slot 29 (Fig. 3) leadi.ng into an open sided hole 30, the hole being provided with opposing spur~ 31.
- Mushroom-headed pinR such as 32 moulded to plastics, strap--- type bail 26 (Fig~ 2) may be snapped into the holes 30 past the spurs 31.
A closure for container body 10 generally indicated at 40 ~ay be moulded from the same or similar material to the container. It has been found that a high-impact polypropylene closure provides the best combination with a polyethylene container. Closure 40 comprises a horizontal cover portion 41 which includes a raised annular portion 42 which acts as a spigot with the recessed bottom wall 14 o~ another can-tainer in stacking filled containers one upon the other.
From the peripheral edge o~ horizontal cover 41 there extends upwardly a U-shaped rim 41a deining an inverted annular recess 44. A substantially vertical axially inner wall ~3 ~f recess 44 is splayed radially outwardly a few degrees and continued some distance below the horiæontal cover 41 at 45.
The inner wall 43 is joined to an axially outer wall 4S by a base of the U-shaped rim 41a. The base comprises a wall 46 :25 splayed at an angle of the order of 45 which provides a sealing region of the rim having a seating surface 46a for cooperation with the container lip and forms a junction be-tween inner wall 43 and an upper wall ~7 of the base extend-ing outwardly thereof. Outer wall ~8 extends do~nwardly from the extremity of the upper wall in spaced relationship .,:' ~ ~ S 5 and substantially parallel to inner ~7all 43 and is resili-ently flexible outwardly from the base.
From an inner surace o~ outer wall 48, there extends an annular bead ~9 having an upper surface 50 which slopes downwardly inwards to the crest o~ the bead at an angle to the vertical which is slightly greater in the normal unflexed state of the outer wall than the angle o~ lower sur~ace 19 of the container lip.
` The ou~er wall also comprises an annular flared skirt 51 which extends radially outwards from the bead on the other side of the bead from the base at an angle of approximately 40 to the vertical. The skirt and a planar annular foot 52 with which lt is provided is of a thickness which is substantially no greater than that o~ the remainder ' 15 of the outer wall above the ~ead.
,l As may be seen, the above closure lends i-tself ;' readily to Being made by injection moulding techniques with a two p~rt mould in which a male mould part forms the under-side surface of the closure and skirt and the upper surface is ~ormed by a female mould part. Removal o the male mould part is efected after removal o the female mould part.
Removal of the male mould part is carried out by :Elexirg of ; the outer wall of the closure thus allowing for the mould part l~Jing within the U-shaped rim to be wit~drawn.
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In applying the closure 40 to the container 10, the closure is oered up to the container opening. ~nner ~all . . .
extension 45 is entered into the opening until a lawer sur-face 53 of the skirt 51 sits on the outer radiused edge 17a -- of the container lip 16. Snap closure by hand is effected by commencing pressing the closure do~n at one spot with the ::
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~S58 lower palm of one hand which urges the skirt outwards at this point by virtue of its engagement with the edge 17a.
Local outward flexing of outer wall 48 caused by movement of the skirt quite easily permits the crest of the bead to ride over the lip 16 so that upper surface 50 of the bead ~;9 now contacts shoulder lower surface 19 of the container ; lip and splayed surface 46a within the annular recess 44 contacts the inner radiused edge 17 of the container rim~
The remainder of the operation is merely one of progressive pressure around the edge of the closure with the palms of both hands in opposite directions. The pressure required to force the container rim into the closure groove increases progressively until at a position opposite the starting point the closure snaps into place. During this operation, flexure o~ the outer wall o the closure has increased to a fl maximum at snap-down point while distortion of the container rim has been minimal.
In the snap-down position, peripheral contact ' ; be~ween rim radius 17 and splayed seating surface 46a is made in a substantially tangential fashlon; substantial ~ f portions of shoulder lower surface 19 and bead upper sur-f~ ace 50 are in full contact. No other parts of rim 16 ~ contact any other parts of recess 44~ In its final posi~ion, ,:
~:~ outer~wall 48 of the closure is in an ou~wardly resiliently ,: !
, ~ 25 fle~ed state. Because of its resilient nature, which in- ~ ~
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cludes that of the bead and the skirt, a considerable con-strictive force is placed upon the shoulder surface 19. ~-:, ; Interaction between sloping surfaces 19 and 50 is such as to : :
' ~ ~pply a downward force to the closure thereby seating~splayed ~ ` 30 surface 46a more firmly against the radiused inner edge 17 of ,~. ' .
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the container ~ith a compressive loading~ The pressure applied is considerable as it is applied to an annular line of contact between these two suraces and is suffi~ient to overcome minute irregularities in their formation and ensure continuous, fluid-tight contact which would no~ obtain with plane surface-to-surface contact.
Removal of the closure is quite simple, being merely a matter of applying leverage under the skirt Sl and against the upper surface of flange 20 on the container with .
; 10 a screw driver or like tool. ~orking progressively around the container will release the closure fully and allow its ' complete removal with ease.
Becauqe the skirt tends towards an axiall~ straight line rela~ion~hip with the remainder o~ wall 48, there is a tendency for the outer wall to 1ex about a point towards the base thus assisting in removal of the bead from around the shoulder~ Although the skirt is no thicker than the wall above the bead, there is little or no tendency for the skirt itself to flex relative to the wall above it at least until the bead has been stretched around the shoulder 18.
.:, The container according to the invention and also according to the embodiment descr~bed above, provides an efficient seal for fluid-tightly sealing any liquid and in - particular paint within the container whi~e the seal may be made by hand pressure. This is largely because of the single point contact along the line of sealing engagement at edge 17 and surface 46a which provides a continuous unbroken seal. The seal is found to be more efficient than in con-structions having container bodies and closures engagable over two annular areas of contact, which in practice result 1t)5589~ ~ ~
in varied pressure being applied ~irst to one and then the other area of contact because of dificul~ies in manufactllre and fitting. In the latter case, leak paths can be caused.
The seal is also a better seal than one in which there is a large area of contact when surfaces are engaged over a sub stantial distance in axial cross-section as such surfaces - would require to be very care~ully prepared to enable them to provide complete sealing contact.
Further, because of the flared skirt extending at an angle of 4C to the vertical and there is little or no tendency for it to flex relative to the remainder of the wall above it, there is no reason or the provision of a much ~hicker sec~ion o plastics material for the skirt which ; could cause shrlnkage distortion p~oblems ater moulding~
i 15 It should be ~mderstood that minor changes in configuration and materials may be made without departlng ~-from the spirit of the invention and the scope of the appended claims. In particular, the materials mentioned above for the container body and closure may be replaced by other mate~ials which have suitable characteristîcs for the purpose of the application such as, for example, suitability o modulus of stiffness.
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A container comprising 2 container body and a closure both being of plastics material, the body having an annular wall defining an opening and a lip around the open-ing, the lip having a sealing region surrounding the opening and a radially outwardly directed shoulder spaced axially along the wall from the sealing region, the shoulder having an abutment surface facing radially outwardly and axially away from the lip, and the closure having a cover portion surrounded by a U-shaped rim, the rim comprising a radially inner axial wall, a spaced radially outer axial wall and a base interconnecting said walls which define between them an axially facing recess of the rim for insertion of the lip between the walls, the rim also including a sealing region at the junction of the inner wall and base, one sealing region being in compressively loaded and tangential engage-ment with the other region to provide substantially a point contact between the regions in a cross-section along the axis and along a single annular line when the lip is received within the rim, and the outer wall incorporating a radially inwardly projecting bead to coact with the shoulder to urge the lip towards the base of the rim and to urge the sealing regions into said engagement, the outer wall being resili-ently flexible outwardly for snap engagement around and release from the shoulder.

2. A container according to Claim 1 in which the rim sealing region is an annular splayed surface at the junction of the inner wall and base and the lip sealing region is a convex edge of said lip,

3. A container according to either of Claims 1 and 2 wherein the outer wall of the closure incorporates a skirt which flares outwardly on the side of the bead remote from the base.

4. A container according to Claim 3 wherein the skirt extends at an angle of between 35° and 45° to the axial direction of the outer wall in the normal and unflexed state of the skirt and the skirt has a thickness which is sub-stantially no greater than the thickness of the remainder of the outer wall apart from at the bead.

5. A container according to either of Claims 1 and 2 in which at least one of the container body and the closure is made from high density polyethylene.

6. A container according to either of Claims 1 and 2 in which the container body is made from high density poly-ethylene and the closure is impact polypropylene.