AU594021B2 - Plastics pail and lid - Google Patents

Description

k

AUSTRAIA

Patents Act 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FORM 594021 FOR OFFICE USE Short Title: Int. Cl: Application Number: SO9 /S.

Lodged: 4 9, 0 4 9.a 9 r, 9* 9* 4 4*4 4 44*.

9s~ Complete Specification Lodged: Accepted: Lapsed: Published: Priority: Related Art: This d oment anellrh on t is )1to 1 9 and is ef I1T dii. Is correct for- 44 4 ft. 4 41 *I 4 TO BE COMPLETED BY APPLICANT C C Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: Rheem Australia Limited Level 26, CBA Centre, Margaret Street, Sydney, New South Wales, 2000 Roland David SOUTH, Robin Michell ADDISON and Kenneth Allan MAXWELL Mr. A.W. Tilley, Rheem Australia Limited, Brodie Street, Rydalmere, NSW 2116 j: c:i i t Complete Specification for the Invention entitled: "PLASTICS PAIL AND LID" The following statement is a full description of this invention, including the best method of performing it known to me:i I ri 2t This invention relates to container assemblies and more specifically concerns a pail-to-lid interlock for providing a liquid tight seal between the respective rims of the pail and lid in the face of both normally and abnormally induced service stresses such as impacts caused by accidental falls of filled containers. Such falls frequently occur during the commercial transportation phase and are a potential hazard recognised by inclusion in standard test procedures for the approval of containers used for regulatory )"000, controlled transport of dangerous goods.

The invention is particularly applicable where O*i both container and lid are moulded from thermoplastics oo materials such as polyolefin types.

00.0 It is particularly suited to the so called "full open head" style of pail manufactured by the injection moulding of an appropriate thermoplastics material. This style is most usefully employed industrially as a container enabling substantially complete emptying of viscous products such as paints, adhesives and printing inks, many of which are classified as dangerous goods. It is more particularly 4 0 envisaged as being most advantageously used for such containers having volumetric capacities in the range of to 25 litres, requiring, when ladings so demand, "Dangerous Goods Approvals" under national or international codes or regulations.

Many prior attempts have been made to solve the problem of the simiultaneous provision of a reasonably easily removable, replaceable and -2 1 v 1 a y .i i ir resealable lid together with an adequate degree of liquid tight integrity against applied stacking loads and to impacts and to stresses such as those imposed during railway journeys which have been known to cause Lids to separate from containers during transportation in stacks.

To the knowledge of the present inventors prior art attempts have been unsuccessful in overcoming all problems. A relatively early Australian patent in the field, number 435466, in the name of W.H. Roper et al, discloses a reasonably successful solution to the problem generally although, in that case, the integrity 0 0 of the seal is very reliant on the provision of a resilient gasket at the pail-to-lid interface. Such gasketted lids are relatively expensive in relation to the moulded lid without gasket and so the public would be well served to have available as an alternative an effective pail with lid not requiring a resilient gasket. Furthermore, the pre~sent invention is as economical of plastic resin consumption as comparable prior art pails of like type and capacity. Several other prior art pails of the type have been proposed but C C it is known that they do not provide the degree of integrity required by all segments of the market. The present inventors are generally aware of many related disclosures in this field including for example, Australian patents 491578, 512734, Australian patent applications 51843/79, 78504/81 and 21773/83.

This invention offers new and useful improvements to the interlock achieved between the H -3pr r": ;i container and lid in a full open head style injection moulded plastic pail and lid, or at least offers the public a useful choice.

The invention consists of a pail-to-lid interlock, not essentially reliant on a resilient gasket in the interlock region but which nevertheless provides hitherto unsurpassed ability to maintain leaktightness under adverse impact induced stresses as well as stacking load or superimposed load stresses.

The lid has a sealingly engageable recess at I its rim region which, with transient deformation during the fitting operation in the manner of a "snap fit", engages a complementary bead located around the upper open periphery of the container. The lid features specific location members, recesses and particular reinforcements as will be described with the aid of figures,those features which acting together provide the desirable performance required by the purchasing public in their desire to most economically comply with legally

I

't0 mandated regulations for the transportation of dangerous goods. The lid may on its first application be sealed t with a high degree of integrity of seal as necessary to *t C S t withstand the rigors of the commercial transportation environment, but may then be readily modified, upon receipt by the user, to convert it to an easily reopenable and resealable container adequate for safe storage, or minor (as distinct from commercial) transportation. The lid features a central moulding.

detail to improve control of variable shrinkage sometimes observed during serial production on ~Ji< I I 4 i v 1 6 1 1 71 00@4 I I a. e o 0 a. 0 9 0 I a a.

0* I 0 940 *001 *1*O 00 a 0 o *0 99 a *1 0* ~o *0 a. a a commercial injection moulding equipment.

The invention will be more fully understood from the following description of a preferred embodiment of a container, lid and their inter-engagement; the description making reference to the accompanying drawings in which:- Figure 1 is a half section fragmental elevation view of a container without lid fitted.

Figure 2 is an enlarged fragmental sectional view of the lip region of the container of Figure 1, the view being taken through the section plane 2-2 of Figure Figure 3 is an inverted plan fragmental view with accompanying third angle projection of a half section elevation view of a lid.

Figure 4 is an enlarged fragmental sectional view of the rim region of a lid, the view being taken through the section plane 4-4 of Figure 3, and Figure 5 is a fragmental half sectional elevation view of a container with lid fitted.

Figure 1 of the drawings shows an injection moulded plastics pail 10 which in the preferred example is slightly tapered to enable empty containers to be nestable one inside the other, but this is not an essential requirement.

The container is described by the following terms with associated numerals on Figure- Pail as a whole 11 Top (open) end 12 Peripheral wall 4F

I

4 i

L

0*040 0 5 0 000* @0 0 08 o *Q 04 0 900 0 0090 04*4 0 00 0 4 0500 50 0 1 4 4t 4 t

S

4'

C

4 13 Lip 14 outwardly directed bead Circumferential skirt 16 Hole for wire handle 17 Lid prising shoulder Figure 2 shows enlarged the following features of Figure 1: 12, 13, 14 and 17.

Figure 3 shows an injection moulded plastics lid 20 which is capable oli engagement with the open end 11 of pail 10. The lid is described in relation to Figures 3 and 4 in the following terms.

20 Lid as a whole 21 Inverted U-shaped rim 22 Telescopically fitting wall 23 Engagement barb 24 Radial ribs 25 Locating ribs for suPerimposed pail in a stack 27 Step in closing wall 29 Inwardly directed ring shaped stiffener 31 Slotted holes -to assist lid first removal 33 Junction point 34 Reinforcement ring on outer skirt of rim Radial reinforcing rib termination (inner) Figure 5 in showing the inter-engagement of the lid and pail uses numerals related to prominent features established in Figures 1 to 4.

Referring to Figures 1 and 2, the pail 10 has -6- A"4

I

ri lip 13 situated at the upper extremity of the peripheral wall 12 and terminated by radially outwardly directed bead 14. At a relatively short distance down the external surface of the peripheral wall is a circumferential skirt 15, having two diametrically opposed holes 16 to receive a wire carrying handle (not shown). Extending around the full periphery of the container at a position intermediate between the outwardly directed bead 14 and the container circumferential skirt is a lid prising shoulder 17.

The circumferential skirt 15 serves in reinforcing the upper region of the pail and in assisting to retain the circularity of the pail opening. As well, it provides a location suitable for attachment of the wire carrying handle.

o 9,a o o a 99 9r 0**9 I .0 it' a.

*9lt 9I~ Referring to Figures 3 and 4, the lid 20 has an inverted shaped rim 21 (when viewed in cross-section) made up of a telescopically fitting wall 22 which forms part of and extends the radially innermost leg of the inverted shape. The outer leg of the inverted has a circumferentially continuously extending engagement barb 23, and skirt reinforcement t' 34. At locations spaced around the circumference, there are six slotted holes 31 extending through the skirt to enable the convenient insertion of the blade of a pointed trimming knife so that the skirt reinforcement 34 may be severed just below and, if desired, above some or all of the slotted holes provided.

The cutting of the skirt reinforcement 34 is intended to enable, without precluding future

I

:i ii Ji 7

C

i sk 1 .l~lI..

47/ 0 w reusability, the simplified first opening of the container once it reaches its point of use. The lid has ffEatures moulded in the closing wall spaced between the inside diameter of the wall 22 and the centre.

These include a number of locating ribs 25 to assist in centralising a superimposed pail of the same type when stacked on the lid, so that the base of such superimposed container is guided inside the rim of the lid to make located contact with the lid of any like closed container immediately below it in a stack. This accuracy of location is considered important to cause o uniform distribution of load transference in a column Spo like manner to the substantially vertical wall of the lower pail or pails bearing the load in a stack. On the central portion of the lid there is also provided a step 27 preferably inwardly directed (with respect to the inside of the closed container). Generally close to *this step is ring shaped stiffener 29.

Interconnecting the ring shaped stiffener 29 e and the inside face of the telescopically fitting wall 22 is a series of many inwardly directed radial ribs 24 SzT which intersect wall 29 and extend radially and inwardly to intersect the inside (lower) surface of the closing wall of the lid at inner termination point 35. The inwardly directed ring shaped stiffener, the step in the Sclosing wall and the series of radial ribs acting in conjunction provide a useful and highly advantageous injection mouldable shape which provdies to the finished lid and, in its interconnection to the pail disclosed, a hitherto unobtained resistance to leakage resulting from 1 l 1 1 L ~'Ii -:i distortion caused by substantial impacts involving the pail-to-lid inter-engagement. Such impacts would typically occur in the event of the closed container, when substantially filled with liquid being dropped, lidded end down, from a 1.2 metre high release point, to strike a substantially unyielding surface.

Figure 5 shows the manner in which the lid interlocks with the container. From Figure 5 may be seen that a space is provided between the rim skirt circumferential reinforcement 34 and the lid prising *shoulder 17. Whether or nozE some or all the holes 31 low4 to assist lid removal have been severed, one or more prising levers may be inserted in the space provided and 9 the lid may be locally deformed to disengage the engagement barb 23 from the outwardly directed bead 14 OIE the container. From that single -localised disengagement the barb may be progressively disengaged quickly around the full lid circumference. Lid resealing may be achieved by locally engaging the barb and outwardly directed bead then progressively engaging j the remainder with, for example, the aid if necessary of r a number of blows from a mallet or equivalent aimed at points firstly close to and then progressively further away from the point of first engagement of the barb and bead.

Thus the lid and pail are provided with a convenient means of deliberate separation which does not detract from their assembled leaktightness during times of transportation stresses and storage stresses of V substantial magnitude.

Claims (3)

1. 2. The pail-to-lid assembly of claim 1 wherein t 4 C C C C r t c r *CC 9*R S sr a ':lt 1r 10 i1 rI each component is injection moulded from high density polyethylene.
2. 3. The pail-to-lid assembly of claims 1 and 2 wherein the capacity of the closed pail lies in the range of 5 to litres.
3. 4. The pail-to-lid assembly as described in the attached specification together with reference to Figures 1 to DATED this 8th day of December 1989 0@ 0 RHEEM AUSTRALIA LIMITED *004 4: C t4 C vC C f TC /I -11