AU685801B2

AU685801B2 - Roofing profile

Info

Publication number: AU685801B2
Application number: AU66079/94A
Authority: AU
Inventors: Christopher Lee Healy; David John Lawrence
Original assignee: Stramit Corp Pty Ltd
Current assignee: Stramit Corp Pty Ltd
Priority date: 1993-06-29
Filing date: 1994-06-28
Publication date: 1998-01-29
Anticipated expiration: 2014-06-28
Also published as: AU6607994A

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT e o o Invention Title: ROOFING PROFILE Applicant: STRAMIT CORPOrATION LIMITED 0* t The following statement is a full description of this invention, including the best method of performing it known to me: ROOFING PROFILE The present invention relates to an improved profile for roofing or other cladding material.

Cladding sheet often incorporates a plurality of rib formations which are spaced apart across the sheet in a lateral direction between longitudinal edge regions of the sheet.

The rib formations are designed to improve the sheet performance, for example by increasing the strength of the sheet or improving its capacity to channel water across the major surface of the sheet. The rib formations extend transverse to the lateral direction of the sheet to fGrm an alternating series of crests and troughs across the sheet and may be in a form of regular corrugations or may include a series of upstanding ribs which are interspaced by pan sections.

A common method of fixing the cladding sheet in place is by way of fasteners which pass through the sheet into the underlying structure. An aimr of the present invention is to provide a cladding sheet of the above type which is adapted to be affixed by this method and which exhibits enhanced peirformance as compared to previous cladding profiles.

InI a first aspect, the present invention provides a cladding sheet of the type having first and second longitudinal edge regions spaced apart in a lateral direction of the sheet, the sheet being arranged to be fixed to an underlying structure and including a plurality of rib formations which form a pattern of crests and troughs across the sheet in the lateral direction, each rib formation extending in a direction transverse to the lateral

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direction between outer and inner margins relative to the underlying structure to which the sheet is to be fixed, and wherein selected ones of the rib formations each further include at least one fastener receiving formation adapted to receive a fastener for fixing the sheet to the underlying structure, each fastener receiving formation comprising a laterally extending shelf situated intermediate the inner and outer margins of its associated rib formation.

Preferably the fastener receiving formations are located substantially at the neutral axis of the cladding sheet.

The arrangement of the present inventi,3n provides significant benefits over previous cladding systems where the fasteners are located through the sheet at either the uppermost part of the crest, or within the lowermost part of the trough. Bending stress is one of the major stresses induced on a cladding sheet in its operation. This stress is predominantly caused by wind uplift, and the neutral axis represents the line of zero fibre stress in the sheet when it is subjected to bending. Accordingly, by locating the fasteners closer to the neutral axis of the sheet, substantial improve:nents in the wind uplift resistance of the sheet is attained. This is particularly important in cyclonic conditions which causes repeated high loading which can lead to fatigue failure.

In a further aspect, the present invention provides a cladding sheet of the above type when affixed to an underlying structure by fasteners which are secured to the structure and which extend through and engage the fastener receiving formations.

:i In yet a further aspect, the present invention provides a cladding system which includes a cladding sheet of the above type and a plurality of fasteners, the fasteners being operable to be secured to an underlying structure and being arranged to extend 0o ~through and engage the fastener receiving formations so as to affix the cladding sheet to the underlying structure.

.to, In yet another form, the present invention provides a method of securing a cladding 5 sheet to an underlying structure including the steps of: providing a cladding sheet of the above type on the underlying structure; and S(ii) locating fasteners through the fastener receiving formations into the underlying structure, the fasteners engaging the fastener receiving formations and the underlying structure to thereby fix the cladding sheet to the underlying structure.

Further preferred embodiment of the present invention will now be described with peference to the accompanying drawings, in which: Fig. 1 is an end view of a first preferred roofing profile according to the invention; Fig. 2 is a detail of the edge part of the profile of Fig. 1 when overlapping with an adjacent similar sheet and fastened to a supporting structure; and Fig. 3 is an end view of a second preferred profile according to the invention.

The profile of Figs. 1 and 2 is of constant cross section throughout its length and has a number of rib formations 5 which form a pattern of crests 10 and troughs 11 across the sheet. Each rib formation extends in a transverse direction of the sheet between anll outer and inner margin (6 and 7 respectively). In the arrangemernt of Figs. 1 and 2, the outer margins 6 form the outermost part of the crests 11 whereas th- inner margins 7 form the innermost part of the troughs 11.

Each rib formation includes opposing sides which merge at their respective outer margins 6. In the profile of Figs. 1 and 2, the first side portion is arcuate whereas the second side portion has a generally stepped configuration which includes a shelf 12.

~Moreover the longitudinal side edge regions have modified overlap 13 and underlap 14 end portions, the engagement of which is illustrated in Fig. 2.

Each shelf portion is formed as a stepped-dow'n end from the respective crest and may be substantially horizontal or siope slightly downwards towards the adjacent trough.

The shelf thus forms a surface well adapted for penetration by fasteners such as the self-drilling screws 15 commonly used in the fixing of roofing she .ts.

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As shown in Fig. 2, one edge of the sheet ends with the flange depending down from the edgemost shelf. The underlap portion 14 on the opposite edge of the sheet is formed to follow the profile of the edgemost shelf of the adjacent s'eet and has a leg 16 extending substantially vertically downwards. This provides support for the edgemost shelf during fastening and also results in efficient use of material, as it is not necessary to extend the underlap portion under the entire final crest.

By fastening the sheet through the shelves 12 rather than at the crests 10 or troughs 11, the fasteners exert restraining forces on the claddin' sheet closer to the neutral axis of the sheet. The neutral axis represents the line of zero fibre stress in a sheet which is subjected to bending and is located intermediate the outmost margins of the rib formations. This occurs as the material in the rib formations 5 provide the majority of the resistance of the sheet to bending stress.

Bending stress is predominantly caused by wind uplift and is one of the most significant stresses induced on the cladding sheet in its operation. These stresses induce compressive stresses which lead to buckling in thin metal profiles, which is a leading cause of failure. Accordingly, by locating the fasteners through the shelves 12, substantial improvements can be attained in wind uplift resistance of the arrangement, which is particularly important in cyclonic conditions.

A further advantage of the arrangement of the Figs. 1 and 2 is that the step-down to the shelf forms a shadow region which may make the fastener heads less visually prominent. Also, the fasteners required are shorter than those needed to fix through the crest, allowing cost savings and increased ease of installation.

:,20 fig. 3 illustrates a second roofing profile according to the invention. In this profile, @9 major and minor rib formations (5,19) are provided. The major rib formations 5 define the outmost parts of the crests 17 of the sheet and include shelves 18 on opposing sides 8, 9. The minor rib formations 19 are positiGned in the troughs 10 formed by adjacent major rib formations 5 and extend to a height intermediate the crests 17 and the troughs 20. With this arrangement, the shelves are located only on selected ones of the rib formations. However, the panel may be fixed to the underlying structure by not only securing the fasteners through the shelves 12 but also additional fasteners may be located through the minor rib formation 19, While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present .:.,embodiments and examples are therefore to be considered in all respects as illustrative vfr .ti J q I I i!-o4 'I'll, OLM and not rostrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalencey of the claims are therefore intended to be embraced therein.

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Claims

1. A cladding sheet of the type having first and second longitudinal edge regions spaced apart in a lateral direction of said sheet, said sheet being arranged to be fixed to an underlying structure and including a plurality of rib formations which form a pattern of crests and troughs across said sheet in said lateral direction, each rib formation extending in a direction transverse to said lateral direction between outer and inner mar!' relative to the underlying structure to which the sheet is to be fixed, and where,, selected ones of said rib formations each further include at least one fastener receiving formation adapted to receive a fastener for fixing the sheet to the underlying structure, each fastener receiving formation comprising a laterally extending shelf situated intermediate the inner and outer margins of its associated rib formation.

2. A cladding sheet according to claim 1, wherein the fastener receiving formations are located substantially at the neutral axis of said cladding sheet.

3. A cladding sheet according to either claim I or 2, wherein the outer margins of said rib formations form the outermost part of said crests and wherein said inner margins of said rib formations form the innermost part of said troughs.

4. A cladding sheet according to any preceding claim, wherein each rib formation includes generally opposing first and second side portions, said side portions of respective rib formations merging together at the outer margin of that formation.

5. A cladding sheet according to claim 4, wherein at least one of said fastener oo receiving formation is located in each of said first and second side portions of said selected rib formations. p S

6. A cladding sheet according to either claim 4 or 5, wherein the first arid second 25 side portions of respective rib formations are symmetrical about an axis passing through said outer margin of that rib formation. O

7. A cladding sheet according to claim 4, wherein a said fastener receiving formation is iormed in only one of either said first and second side portions of at least one of said selected rib formations.

8, A cladding sheet according to claim 7, wherein said first side portion extends in the lateral direction of the sheet by a substantially greater amount than the second side portion, I I

9. A cladding sheet according to either claim 7 or 8, wherein said fastener receiving formation is located in said second side portion, said second side po 'ion incorporating upper and lower portions which are interconnected by said fastene \cuiving formation, said upper and lower portions being substantially linear and ex! Ing outward!y such that said second side portion has a generally stepped configuratioin.

A cladding sheet according to any preceding claim, wherein the sheet is arranged to be juxtaposed with a like sheet with the first edge region of one sheet being adapted to overlap the second edge region of the other sheet such that a said selected rib formation is formed at the overlapping edge region, wherein said first edge region includes said fastener receiving formation located proximate to a terminal end of said first longitudinal edge region and wherein said second edge region includes an upwardly extending support member adapted to extend under and support a said fastener receiving formation of the first edge region of a like sheet.

11. A cladding sheet according to any preceding claim, further including substantially planar pan sections interconnecting said rib formations.

12. A cladding sheet according to any preceding claim when affixed to an underlying structure by fasteners se;ured to said structure and which extend through and engage said fastener receiving formations,

13. A cladding system including a cladding sheet according to any one of claims 1 to ~i and a plurality of fasteners, said fasteners being operable to be secured to an underlying structure and being arranged to extend through and engage said fastener receiving formations so as to affix said cladding sheet to said underlying structure.

14. A method of securing a cladding sheet to an underlying structure including the steps of: providing a cladding sheet according to any one of claims I to 11 on the 9040: underlying structure; and (ii) locating fasteners through said fastener receiving formations into said underlying structure, said fasteners engaging with said fastener receiving formations and said underlying structure to thereby affix said cladding sheet to said underlying structure. 0#V4OOgjIt A cladding sheet substantially as herein described with reference to the accompanying drawings. DATED: 30 September 1997 PHILLIPS ORMONDE FITZPATRICK Attorneys for STRAMIT CORPORATION LIMITED a a a.. a a a. U a a. a a a a a. a a.. *.aa a. U a. a a a a a a.. a ff 1 I _IrslL i ~L I sL h 4 0, ABSTRACT A cladding sheet profile has crests (10) and troughs (11) and further includes fastener receiving formations (12) of an intermediate height for fasteners (15) fixing the sheet to an underlying structure. Each fastener receiving formation may be a shelf formed as a stepped-down portion at the end of a crest. *oo 10 Recommended Figure: Fig. 2. S P 4 06 S *e I