AU619017B2 - Lug-cover - Google Patents

Description

_I_

P I DATE 12/12/89 6 19 Opr JP DATE 25/01/90 APPLN. ID 37439 89 PCT NUMBER PCT/AU89/00227 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 43/03, B21D 51/44 (11) International .ication Number: WO 89/11423 Al (43) International Publication Date: 30 November 1989 (30.11.89) (21) International Application Number: (22) International Filing Date: Priority data: PI 8429 25 May 1 PCT/AU89/00227 23 May 1989 (23.05.89) (81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (European patent), FR (European patent), GB (European patent), IT (European patent), JP, LU (European patent), NL (European patent), SE (European patent), US.

Published With international search report.

988 (25.05.88) (71) Applicant (for all designated States except US): RHEEM AUSTRALIA LIMITED [AU/AU]; Brodie Street, Rydalmere, NSW 2116 (AU).

(72) Inventor; and Inventor/Applicant (for US only) DUFFY, Douglas, C.

[AU/AU]; 114 Marsden Road, West Ryde, NSW 2114

(AU).

(74) Agent: TILLEY, Rheem Australia Limited, P.O.

Box 6, Rydalmere, NSW 2116 (AU).

(54) Title: LUG-COVER (57) Abstract A lug-cover (10) to close and seal a container such as a pail, especially for transport of dangerous goods, in which the lug-cover is provided with a drawn wall having extending circumferentially around it a stepped ledge circumferentially divided into narrower portions (19) and wider portions (18) which alternate segmentally around the circumference of the stepped ledge and extend axially downwardly in corresponding non-circularity to corner radii (16) corresponding respectively with th: narrower and wider portions of the stepped ledge. The circumferential extent of each narrower and wider portion is different from other narrower and wider portions.

During manufacture the lug-covers are rotated before being stacked. Consequently there is a very high probability that adjacent lug-covers in a stack will have been rotated through different angles and so the narrower ledge portions (19) of one lug-cover are supported on the wider ledge portions (18) of the lug-cover below it. The lug-covers are capable of providing a superior integrity seal to a pail, easy separability after being stacked and transported to a point of use and ease of intentional removal from the pail.

SWO 89/11423 PCT/AU89/00227 -1- 1 LUG-COVER

BACKGROUND

This invention relates to a mass-produced metal cover or lug-cover for a pail or drum. It has a particular application in the case of a multi-lugged lug-cover of the general type illustrated in the accompanying Figures 1 and hereinafter referred to as a lug-cover.

The invention concerns the provision of new features in a lug-cover for the purpose of substantially preventing the problem of lug-covers jamming or binding together after having beei: transported in stacks. The problem has been more evident in palletised stacks particularly when other loads are superimposed but known types also tend to jam together even under their own weight with the influence of vibration in the transportation environment. Jamming together is likely to be a greater problem when the lug-covers have been painted or lacquered. It is to be understood that normal practice is to transport quantities of empty pails separately from their lug-covers prior to filling and sealing, thus for convenience the lug-covers are transported on pallets in stacks containing typically 50 or more.

One means of overcoming this problem of jamming of lug-covers has been in widespread use already and is illustrated in the accompanying Figure 10 and explained in more detail below.

However, continued use of the known means was found to cause a substantially insurmountable difficulty when a pail to lug-cover closure was developed for complying with regulations for the transport of dangerous goods. One form of known lug-cover closure required among other things deletion of the previously known non-jamming means to enable it to meet its primary object of resistance of leakage caused by drop impact and excessive internal pressure.

WO089/11423 PCf/A U89/00227, -2- 1 A further proposed solution to the problem of preventing stacks of pail lug-covers jamming together involved forming ai.symmetric outwardly directed deformations on some lugs of each cover. This was found to be disadvantaged by manufacturing difficulties and increased risk of accidental cuts when handling. Accordingly the present invention has been devised to overcome known prior art limitations and disadvantages.

SUMMARY

The invention consists of a lug-cover to close and seal a container opening having a curl~ed rim extending around the opening, said lug-cover comprining a press formed sheet metal article including; a central substantially planar circular portion; a corner radius extending outwardly and upwardly from the circumference of the central portion; a drawn wall extending upwardly from the uppermost extent of the corner radius; a stepped ledge in the drawn wall extending circumferentially around the drawn wall and dividing it into two substantially cylindrical form lower and upper strips joined by said stepped ledge; a curved gasket groove extending upwardly and outwardly from V the top edge of said upper strip then downwardly and outwardly to meet a substantially cylindrical peripheral strip extending downwardly a short distance; and a plurality of spaced-apart lugs extending downwardly from the lower edge of said peripheral strip; and wherein said stepped ledge is circumferentially divided into first, narrower portions and second, wider portions alternately located around the stepped edge.

Preferably each narrower ledge portion has a different WO 89/11423 PCT/AU89/00227 -3- 1 circumferential extent compared with other narrower ledge portions in the lug-cover.

The significance of the preference for differing circumferential extents of the narrower ledge portions is that this makes probable, in two adjacent stacked lug-covers, several segmental contacts between narrower ledge and wider ledge portions between adjacent lug-covers. This results because of a negligible probability that adjacent lug-covers in a stack will have been rotated through identical angles as a result of operations performed on the lug-cover between the pressing and the stacking operations.

Preferably each narrower ledge portion is coextensive with its adjacent wider ledge portions and upper and narrower strips of the drawn wall via smoothly radiused transition regions.

Preferably the width of the wider ledge portions is in the range of twice to four times the metal thickness of the lug-cover in which it is formed.

More preferably the width of the wider ledge portion is approximately three times the metal thickness of the lug-cover in which it is formed.

Preferably the diameter at the location of the upper strip is formed to provide a narrow band of the lug-cover having a tight fit without clearance between the lug-cover and the opening in the top of the pail when the lug-cover is sealed to the pail.

Preferably the height dimension of the upper strip is selected to be as small as possible consistent with the provision of said tight fit between the lug-cover and the opening in the top of the pail.

WO 89/11423 PCr/A U89/00227, -4- 1 Preferably the lower strip is formed to provide a width difference between the wider and narrower ledge portions at H least equal to the thickness of the lug-cover.

More preferably the lower strip is formed to provide a width H difference between the wider and narrower ledge portions which is 1.5 times the thickness of the lug-cover.

The significance of the preference for minimising the height dimension of the upper strip is that the superior performance, required of the lug-cover to pail seal as a whole in transportation of dangerous goods, is aided by a tight size-for-size fit between the lug-cover and the mouth of the pail. However, the unusually pronounced inward arid upward deformation of the lugs required in this seal tends to tighten the fit between the lug-cover and the pail by inward deformation of the pail wall. If extended too far down the drawn wall of the lug-cover the tightness would tend to make very difficult the removal of the lug-cover. The clearance between the drawn wall of the lug-cover and the wall of the pail just below its rim, as provided in this invention V because of the provision of the stepped ledge, enables both ease of intentional removal of the lug-cover and the required non-jamming of the lug covers after having been stacked for transportation.

Preferably the corner radius measured at its outside surface is at least five times the metal thickness of the sheet metal forming the lug-cover.

Preferably the lugs are formed into a first, upper, radially outwardly flared portion and second, lower, unflared or lesser flared portion downwardly depending from the lower end of said first portion, wherein the first and second portions are positioned and dimensioned to be effective in providing support between adjacent like lug-covers in a stack by the end extremities of lugs of one lug-cover engaging a part of the first flared portion of the lug-cover below it in the stack.

WO 89/11423 PCT/A U89/00227 1 Preferably the first flared portion of the lugs is at an angle in the range 5 to 10 degrees from the vertical.

More preferably the upper flared portion of the lugs is at an angle of 8 degrees from the vertical.

The invention consists also of a method of forming a sheet metal lug-cover for a pail comprising the steps of: forming a flat substantially circular blank having around its periphery a plurality of outwardly extending lug profiles having holes formed in each lug profile to be useful in removing the lug-cover subsequent to it having been crimped to the opening of a pail; drawing the blank formed in the first operation to provide a second operation form having a flat central disc region surrounded by a vertically upwardly extending drawn wall from the top of which extends an outwardly extending flange; forming the second operation form into a third operation component having a gasket groove formed at the top of the drawn wall, an angularly outwardly flared upper lug portion and a lower, non-flared or less flared lug portion and a stepped ledge formed in the drawn wall and comprising first, narrower portions and second, wider portions alternately located around the stepped ledge; flowing-in a gasket compound in liquid form into the gasket groove while rotating the inverted third operation component; and Scuring the gasket compound to form a cellular, elastomeric gasket in the lug-cover.

WO 89/11423 PCT/AU89/00227 6- 1 DESCRIPTION OF THE DRAWINGS The invention is explained in greater detail by description of an example in the form of a particularly preferred embodiment and variations thereof as illustrated in the accompanying Figures.

Figure 1 is an unscaled reduced size part-elevation, part-section view of a metal lug-cover according to the invention.

Figure 2 is projected plan view of the lug-cover of Figure 1.

Figure 3 is a first schematic cross-sectional view showing only the cutting plane III-III as indicated in Figure 2.

i Figure 4 is a second schematic cross-sectional view showing ai only the cutting plan IV-IV as indicated in Figure 2.

li 20 Figure 5 shows to an enlarged scale a cross-section of the peripheral region of a metal lug-cover according to the invention in schematically depicted engagement with the rim of a pail prior to crimping the lugs.

Figure 6(a) shows to an enlarged scale a cross-sectioned detail of the peripheral region of a metal lug-cover according to this invention in engagement with the peripheral region of an identical lug-cover when stacked together as for storage and transportation.

Figure 6(b) shows the same features as Figures 6(a) in a cross section angularly displaced from the section shown in Figure 6(a).

Figure 7 shows to a reduced scale a portion of the lug-cover of Figure 1 showing its form after the £'irst pressing operation in its manufacture.

WO 89/11423 PCT/AU89/00227 -7- 1 Figure 8 shows to an unscaled red~uced size, mating portions of male and female halves of a forming die, show open, used to perform the third pressing operation in the manufacture of the lug-cover according to the invention and between the die halves is shown in cross section a portion of the lug-cover after the second and before the third pressing operation in its manufacture.

Figure 9 shows to an unscaled reduced size portions of the die halves of Figure 8, shown schematically in cross-section.

Figure 10 shows plan, elevation and part section views of a known type of lug-cover over which the present invention provides advantages.

DETAILED DESCRIPTION Referring to Figure 1, 2, 3, 4 and 5 the circular lug-cover comprises a generally flat central reion 12 which extends at its radially outer extremity via a corner radius into a drawn wall extending vertically upwardly from the centre reion 12. As best seen in Figures 3 and 4 the drawn wall is formed to comprise four distinct portions as follows:- 425 from the upper extremity of the corner radius a substantially cylindrical but not perfectly cylindrical form lower strip 17 extends upwardly, a narrower portion stepped ledge 18 in Figure 3 and a wider portion stepped ledge 19 in Figure 4 extend outwardly and slightly upwardly from the top extremity of the lower strip 17, and a cylindrical upper strip extends upwardly from the upper extremities of the stepped ledge portions 18 and 19. Those portions 16 of the corner radius (Figure 3) blending the lower strip 17 with the flat central area 12 directly below the wider portions 18 of the stepped ledge are correspondingly more inward-,y directed towards the centre of the lug-cover than portions 15 of the corner radius (Figure 4) directly below the narrower portions 19 of the stepped ledge. A gasket groove 21 which may be W089/1423PCT/AU89/00227 -8- 1 semi-circular in cross-section extends from the top of the upper strip 20 tipwardly and outwardly then downwardly and I outwardly through an angle of approximately 180 degrees.

From the radially outer termination of the gasket groove 21 a peripheral strip 22 of cylindrical form extends downwardly.

From the lower edge of the peripheral strip 22, lugs 24 around the periphery are formed and depend downwardly. An elongated hole 26 in each lug 24 is provided to enable removal of the lug-cover 10 by partially restraightening the lugs after the latter have been bent into a crimped interengagement (not shown) with the rim 28 of a pail (Figure Referring to Figure 2, the lug-cover 10 is divided into an even number of segments, eight as illustrated, by virtue of regions of different radial dimension R1 and R2. The radii Rl and R2 are applicable to the as defined lower strip 17, as best seen by referring to Figures 3 and 4. The larger radius, R1, relates to the circumferential extents of the narrower ledge portions 19 whilIst the smaller radius R2, relates to the circumferential extents of the wider ledge portions 18. The wider ledge portions 18 provide support for the corner radii, 15 and 16 of above adjacent lug-cover in a stack to seat upon, thereby advantageously creating great resistance to being telescopically jammed one inside the other, as will be described with reference to Figures 6(a) V and The segmental dividing lines 30 to 37 in Figure 2 define unequal angles A, B, C, D, E, F, G and H, adding in total to 360 degrees, each angle subtending at the drawn wall the alternating wider portions 18 and narrower portions 19 of the stepped ledge formed in the drawn wall.

With particular reference to Figures 6(a) and the narrower ledge portions 18 of the stepped ledge in the drawn wall of the lower lug-cover make contact with the outside surface of the corner radius 15 of the lug-cover above it.

To be effective in preventing jamming together of adjacent lug-covers there is preferably, in the drawn wall four spaced WO 89/112 PCT/AU89/00227 142 apart wider portions 18 of the stepped ledge separated from each other by part circumferentially extending narrower ledge portions 19. There could be as few as three wider portions 18, or more than four, but presently four is preferred.

The purpose of the unequal angular dimensions A to H as shown in Figure 2 substantially prevent the possibility of an exact match of corresponding portions of the stepped ledge mating in two adjacent lug-covers in a stack. To explain that, it should be noted that the manufacturing steps between press forming the lug-covers including the drawing of the wall and forming the segmentally distinct narrower and wider ledge portions 19 and 18 and stacking the finished lug-covers, involves several feeding steps and one multi-turn rotation step for flowing-in the gasket. These steps result in a complete radomness of angular orientation of lug-covers stacked one above the other, that is, a very high probability of narrower portions 19 of one lug-cover being supported on wider portions 18 of the lug-cover below it. Therefore, the contac-t between adjacent lug-covers in a stack will tend to I, be limited to four localised points. This is conducive to avoiding frictional binding between lug-covers, especially those coated with some softer varieties of paints or lacquers in common use and which would otherwise be particularly prone to being difficult to separate after having been stacked.

Each narrower ledge portion 19 has a different circumferential length compared with other narrower ledge portions formed in the drawn wall of the same lug-cover.

That is, the angles B, D, F and H in Figure 2 are not equal.

With reference to Figure 5, the lugs 24 around the periphery are provided with a downwardly and outwardly flared portion 54 defined by an upper end 52 and a lower end 53. The upper end 52 coincides with the lower extremity of the peripheral strip 22 and the lower end 53 defines the upper extremity of WO 89/ 11423 PCT/AU89/00227, 10 1 a less flared or non-flared second portion 55 of the lugs which second portion has its lower extremity generally coincident to the lower extremity of the lugs 56.

The lowermost tip 56 of any lug 24 of any lug-cover in a stack (other than the bottom one) containing lug-covers oriented with the lugs downwardly as illustrated in Figures 6(a) and engages with at least a point on the downwardly and outwardly flared portion 54 of a correponding lug or lugs of a lug-cover below it in a stack. The lower end portion 55 of the lugs are relatively more easily deflected elastically radially outwardly than the upper end 52 of the lugs and thus the contact between the tips of the lugs assists in avoiding inseparable binding or jamming occurring between the lug-covers after stacking and transporting.

Figure 6(a) shows lug-cover contact occurring at two locations, the wider ledge 18 to corner radius 15 location and the lug tip 56 to lug flared portion 54 location.

Contact at the former one of these locations can be sufficient in providing the predominant non-jamming effect ji but both acting in conjunction is preferred. As shown in Figure non-contact between the stepped portions of adjacent lug-covers can occur where a segment of corner radius 16 is verticallv above a segment of narrower ledge portion 19.

Incidental to the advantage of the present invention as has been described in relation to Figures 6(a) and the presence of the radially inward displacement of lower strip 17 with respect to cylindrical upper strip 20 provides an additional benefit unrelated to non-jamming of lug-covers in stacks, being most important in the broader context of the lug-covers being suited to dangerous goods class of duty.

The nature of the lug-cover to pail seal involves an inward and upward deformation of the lugs using a sealing or WO089/11423 PCr'/AU89/00227 1 crimping tool as described and illustrated in published Australian patent application 7 3752/87. The uncompressed gasket shown cross-hatched in Figure 5 after crimping of the J lugs to effect the seal, is highly compressed to a thickness which may be only 1.5mm or approximately three times the metal thickness. As can be understood from inspection of Figure 5, the cylindrical portion 20 of the lug-cover, upon sealing, enters the cylindrical portion of the open top of the pail opening. The pail opening and lug-cover are dimensioned such that the cylindrical portion 20 and the pail opening are a tight fit. The action of the sealing tool tends to inwardly deform the wall of the pailI 30 just below the rim 28. Because of the clearance provided by the inward displacement of the lower strip 17 the inward deformation of the wall of the pail does not result in excessive tightness between the lug-caver and the pail. This has been found to greatly facilitate the intentional removal of the lid when the lugs 24 have been bent outwardly as is required when removing the lug-cover in order to withdraw the contents.

Certain manufacturing steps are illustrated in Figures 7 and 8. The lug-covers are formed in three sequential press operations, as follows:in the first operation, Figure 7, a flat component 76 is blanked from sheet steel or tinplate, the lugs 24 and holes 11 26 in each lug being formed. In the second operation, the j flat component 76 as first blanked is drawn over a die to form the drawn wall and flanged periphery 78 as shown in Figure 8. In the third operation, the mating male 80 and female 82 parts of the die having the required form to produce the angularly flared portion of the lugs are provided so that the flared lugs are formed as the die reaches the closed position, simultaneously forming the gasket groove (21 of Figure 3) and stepped ledge portions 18 and 19 also.

The parts of the die having the required form to produce the WO 89/11423 PCI/A U89/00227, -12 1 ledge portion in the drawn wall of the cover are illustrated in relation to Figure 9, which shows the male die sectioned schematically as indicated in Figure 8, the different radii used for forming the ledge portions being shown greatly exaggerated. Radii R2 and R4 are associated with producing the wider ledge portions (18 of Figure 3) and radii R3 and R5 are associated with producing the narrower ledge portions (19 of Figure 4) as the die of Figure 8 fully closes.

In respect of a particular illustrative example involving covers made from 0.43mm thickness steel for fitting to pails having an internal diameter at the opening of 285.6mm, values of R2 and R3 fouind to be effective were 0.65mm, that is about times the metal thickness, different. Angles A to H ranging between 39 and 54 degrees were found to be effective.

Referring to Figure 10, the known type of lug-cover 100 is shown for comparison. Many of the elements of the lug-cover in Figure 10 are generally similar to those shown in Figures 1 and 2. The anti-jamming provision consists in Figure 10 of four asymmetrically disposed radially inwardly directed formations, known as stacking nibs 101, in the draw region 102 of the lug-cover. These stacking nibs have been used in the industry for many years and are known to be effective in preventing jamming. However, they have proved to be a serious impediment in attempts to make a superior pail to lug-cover closure adequate for compliance with dangerous goods regulations. When nibs 101 are in the drawn wall 104 it has been found that damaging impacts to the rim of the pail to lug-cover closure when the pail is dropped onto the closure end, are most likely to result in leakage at the stacking nibs. This leakage is due to creases formed in the cover which tend to preferentially form at one or more stacking nibs at the top of the gasket groove 106 allowing compression to be reduced at the gasket to pail rim interface, so resulting in leakage. The known stacking nibs WO 89/11423 PCT/AU89/O0227 13 1 101, as visible in the elevation and section parts of Figure extend as high as the top of the gasket groove, where the nib 101 is inclined partly at an angle of 45 degrees, and Sblends with the top of the groove 106 tangentially.

This contrasts to the height of the stepped ledge portions of the present invention in relation to their position with respect to that of the gasket groove. The radial inward displacement of the known stacking nibs also contrasts with the present invention in which the radial inward displacement is relatively much smaller, being preferably in the range of two to three times the metal thickness of the lug-cover whereas the known stacking nibs are inwardly displaced at least six times the metal thickness of the cover.

V USES AND ADVANTAGES Therefore an alternative means of preventing jamming as described herein has been devised and now enables the practical application of the superior lug-cover to pail closure. The stepped ledge portions having considerable circumferential extent and maintaining tight diametral support for the rim and mouth region of the pail into which it is fitted, provides a lug-cover to pail interconnection highly resistant to damage, lug-covers which do not jam together when stacked and which are readily able to be removed after having been sealed to a pail.

The invention as explained above by description of an example of the invention with respect to a particularly preferred embodiment and variations thereof may be modified in particular aspects obvious to one skilled in the art while still being within the scope of the present invention as claimed below.

L

Claims (8)

1. A lug-cover to close and seal a container opening having a curled rim extending around the opening, said lug-cover comprising a press formed sheet metal article including; a central substantially planar circular portion; ,j a corner radius extending outwardly and upwardly from the circumference of the central portion; a drawn wall extending upwardly from the uppermost extent of the corner radius; a stepped ledge in the drawn wall extending circumferentially around the drawn wall and dividing it into two substantially cylindrical form lower and upper strips joined by said stepped ledge; a curved gasket groove extending upwardly and outwardly from the top edge of said upper strip then downwardly and outwardly to meet a substantially cylindrical peripheral strip extending downwardly a short distance; and a plurality of spaced-apart lugs extending downwardly from the lower edge of said peripheral strip; and wherein said stepped ledge is circumferentially divided into first, narrower portions and second, wider portions j alternately located around the stepped edge.

2. A lug-cover as claimed in Claim 1 which each narrower ledge portion is coextensive with its adjacent wider ledge portions and upper and narrower strips of the drawn wall via I smoothly radiused transition regions.

3. A lug-cover as claimed in either preceding claims in which the width of the wider ledge portions is in the range of twice to four times the metal thickness of the lug-cover in which it is formed.

4. A lug-cover as claimed in Claim 3 in wnich the width of the wider ledge portion is approximately three times the metal thickness of the lug-cover in which it is formed. 1 WO 89/11423 PCT/AU89/00227 15 1 5. A lug-cover as claimed in any one of the preceding claims in which the diameter at the location of the upper strip is formed to provide a narrow band of the lug-cover having a tight fit without clearance between the lug-cover and the opening in the top of the pail when the lug-cover is sealed to the pail.

6. A lug-cover as claimed in Claim 5 in which the height dimension of the upper strip is selected to be as small as possible consistent with the provision of said tight fit between the lug-cover and the opening in the top of the pail.

7. A lug-cover as claimed in any one of the preceding rclaims in which lower strip is formed to provide a width difference between the wider and narrower ledge portions at Sleast equal to the thickness of the lug-cover.

8. A lug-cover as claimed in Claim 7 in which the lower strip is formed to provide a width difference between the wider and narrower ledge portions which is 1.5 times the thickness of the lug-cover. S9. A lug-cover as claimed in any one of the preceding claims in which the corner radius measured at its outside surface is at least five times the metal thickness of the sheet metal forming the lug-cover. A lug-cover as claimed in any one of the preceding claims in which the lugs are formed into a first, upper, I 30 radially outwardly flared portion and second, lower, unflared or lesser flared portion downwardly depending from the lower end of said first portion, wherein the first and second portions are positioned and dimensioned to be effective in providing support between adjacent like lug-covers in a stack by the end extremities of lugs of one lug-cover engaging a part of the first flared portion of the lug-cover be'.ow it in the stack. WO 89/11423 PCT/AU89/00227,

16- 1 12. A lug-cover as claimed in either Claim 10 or Claim 11 in which the upper flared portion of the lugs is at an angle of 8 degrees from the vertical. 13. A method of forming a sheet metal lug-cover for a pail comprising the steps of: forming a flat substantially circular blank having around its periphery a plurality of outwardly extending lug profiles having holes formed in each lug profile to be useful in removing the lug-cover subsequent to it having been crimped to the opening of a pail; drawing the blank formed in the first operation to provide a second operation form having a flat central disc region surrounded by a vertically upwardly extending drawn wall from the top of which extends an outwardly extending flange; forming the second operation form into a third operation component having a gasket groove formed at the top of the drawn wall, an angularly outwardly flared upper lug portion and a lower, non-flared or less flared lug portion and a stepped ledge formed in the drawn wall and comprising first, narrower portions and second, wider portions alternately located around the stepped ledge; flowing-in a gasket compound in liquid form into the gasket groove while rotating the inverted third operation component; and curing the gasket compound to form a cellular, elastomeric gasket in the lug-cover. 14. A lug-cover substantially as described with reference to the accompanying Figures 1 to 5 and 6(a) and 6(b). WO 89/11423 PCT/AU89/00227 -17 1 14. A lug-cover substantially as described with reference to the accompanying Figures 1 to 5 and 6(a) and 6(b). A method of forming a lug-cover substantially as described with reference to the accompanying Figures 7, 8 and 9. I I I 3 hi