AU754564B2

AU754564B2 - Fixing sheet material

Info

Publication number: AU754564B2
Application number: AU14224/99A
Authority: AU
Inventors: David James Alexander Roberts
Original assignee: ITW AFC Pty Ltd
Current assignee: Illinois Tool Works Inc
Priority date: 1998-02-11
Filing date: 1999-01-29
Publication date: 2002-11-21
Anticipated expiration: 2019-01-29
Also published as: AU1422499A

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

S

o* 0 *e Invention Title: Applicant: FIXING SHEET MATERIAL W.A. DEUTSHER PTY LTD The following statement is a full description of this invention, including the best method of performing it known to me: 1 C:\WINWORMSHARONANDREW\VENERAL518013CP.DOC 1.

2 FIXING SHEET MATERIAL This invention relates to devices and systems for securing sheet material to a support, such as a roof or wall supporting structure of a building. It will be convenient to hereinafter describe the invention as applied to fixing sheet metal roofing material, but it is to be understood that the invention has wider application.

Sheet metal roofing material is commonly of corrugated or otherwise profiled form so as to have suitable strength characteristics. The profiling of the roofing material is generally such that the material is formed with a series of parallel ribs and intervening valleys. The top or crown surface of each rib usually has a convex curvature when viewed in transverse cross-section, and in some cases the radius of curvature is quite large so that the top or crown surface appears to be substantially flat. Roofing material in which the ribs and valleys have a relatively high degree of curvature a relatively small radius of curvature) is generally referred to as corrugated, whereas material having relatively flat crown ribs is generally referred to as trapezoid, trapezoidal or square ribbed (hereinafter referred to as "square ribbed"). The form of 0000identification adopted in this specification will be to refer to the roofing material as either corrugated or square ribbed respectively.

Ribbed roofing material is commonly secured to an underlying supporting structure by fastening screws which are passed through the top or crown surface of the ribs. It is necessary to weather-proof the fixing points by providing a suitable seal between the head of the fastening screw and the roofing material. It is also often necessary to protect the roofing material from distortion under high wind loads, and that usually involves providing a relatively large washer or plate between the head of each fastening screw and the roofing material.

Weather-proofing is usually attended to by means of a resilient sealing member located between the roofing material and the wind load plate, and the nature of the wind load plate is generally such that the sealing member needs to be of complex configuration. Such sealing members are therefore relatively CAWINWORD SHARON\ANDREWPROVS518013.DOC expensive and are not always reliable in service.

The configuration of the wind load plate varies according to the profile of the roofing material with which it is to be used. Attached Figures 1 and 2 show typical fixing installations for corrugated and square ribbed sheet respectively.

In both instances the wind load plate 1 is designed to bear down on the roofing material rib 2 at or near the outer periphery of the plate 1. Figures 1 and 2 show the plates 1 correctly installed, but it sometimes happens that the 0.:0 fastening screw 3 is not located at the true center of the roofing material rib 2, so: 1 and that may cause the plate 1 to bear more firmly against one side of the rib 2 0 10 than the other.

Wind load plates 1 of the foregoing kind are not satisfactory even when correctly installed. High wind loading will cause the roofing material to flex so that bending tends to occur at the pressure zones 4 and 5 shown on Figures 1 and 2. Permanent distortion of the roofing material results if relatively severe bending occurs at the zones 4 and 5. If the plate 1 is not correctly installed there will be greater stress at one zone 4 or 5 than the other, and there will then be a greater probability of the roofing material suffering permanent distortion.

It is an object of the present invention to provide an improved system for fixing sheet material to a support. It is a further object of the invention to provide an improved system for fixing profiled sheet material to a support. It is yet another object of the invention to provide an improved load bearing plate for use in fixing sheet material to a support.

According to the invention there is provided a load bearing plate for securing sheet material to a support, said plate having an opening therethrough for the passage of a fastening screw and an under surface of a contour which is different to the contour of the surface of the sheet material which the plate is intended to overlie, said different in contour being such that under normal conditions of use (as hereinbefore defined), said plate bears on the sheet material in a region adjacent said opening and a clearance space exists between said plate and said sheet material outwardly of said region, said plate F being of dished shape in transverse cross-section.

It is preferred that the clearance space progressively increases from a 0CC minimum (possibly zero clearance) adjacent the aforementioned pressure region to a maximum at the outer periphery of the plate.

If a resilient sealing member is interposed between the opposed surfaces of the plate and the sheet material respectively, the aforementioned clearance could be clearance between that member and either one or both of the opposed surfaces.

The clearance could extend completely around the plate opening, or it could extend on each of two opposite sides of the opening. The latter situation will usually exist when the plate is intended to overlie the crown surface of a rib, and in that event each of the two zones of clearance will extend towards a respective one of the two longitudinal sides of the rib.

Reference to "normal conditions of use" in this specification is to be understood as including conditions under which the sheet material is not subjected to wind or other loading 'such as to cause it to flex relative to the load bearing plate. When the sheet material is subjected to such loading it will tend to flex about the aforementioned pressure region so as to lift into the clearance •...*space at each clearance zone. As the sheet material lifts there is a progressive increase in the surface area of the sheet material which presses against the 000 overlying plate, and the resulting distribution of stress minimises the possibility S 20 of the sheet material experiencing permanent distortion.

The present invention further provides a fastening system for securing sheet material to a support, said system including a load bearing plate arranged to overlie said sheet material and having an opening therethrough, a fastening screw passing through said opening and said sheet material and threadably engaging said support, the surface of said plate facing said sheet material having a contour such that said plate bears against said sheet material in a region adjacent said opening and a clearance space exists between said plate and said sheet material outwardly of said region, said plate being of dished shape in transverse cross-section.

The invention will be hereinafter described with particular reference to T the fixing of profiled or ribbed sheet material, but the concept upon which the z invention is based could be also used in fixing other types of sheet material r-WWRMWRNWAMW"O ju 1013DCC including flat or relatively flat sheet material.

It will be convenient to hereinafter describe the invention in greater detail by reference to the accompanying drawings which show example embodiments of the invention. The particularity of those drawings and the related description is not to be understood as superseding the generality of the preceding broad description of the invention.

Figures 1 and 2 show a cross-sectional view of prior art fixing installations for corrugated and square ribbed sheets respectively.

Figure 3 shows a cross-sectional view of a fixing installation for corrugated sheeting according to one embodiment of the invention.

Figure 4 shows a cross-sectional view of the wind load plate shown in ::Figure 3.

Figure 5 shows an enlarged cross-sectional view of the fixing installation of Figure 3.

Figure 6 is a plan view of the wind load plate of Figure 3.

Figures 7 and 8 show a fixing installation for square ribbed sheeting according to a further embodiment of the invention.

Figure 9 shows a fixing installation for a flat sheet according to a further embodiment of the invention.

Figures 3 to 6 show one form of load bearing plate 10 according to the *00 invention which is designed for use in association with corrugated metal sheet 11 intended for use as roofing material. The sheet 11 is secured to an underlying roof batten 12 of metal or other material, by means of a number of fastening screws 13. Cooperation between each screw 13 and the batten 12 may be as shown by Figures 1 and 2. Furthermore, the fastening screw 13 may be of the self-drilling and self-tapping kind, an example of which is shown by Figures 1 and 2.

The fastening screw 13 passes through an opening 14 (Figures 4 and 6) formed through the plate 10, preferably at the approximate center of that plate.

It is preferred, as shown by Figure 4, that a cavity 15 is formed below the opening 14 so as to receive a resilient sealing washer 16. The cavity can have any suitable shape and is preferably formed to be frusto conical, or C:\WINWORA SHARON\ANDREWROVS%518013,DOC 6 approximately frusto conical. The cavity 15 as shown in Figure 4, is shown in an exaggerated form, and in practice, a typical plate 10 could have a cavity depth of approximately 1.5mm. As shown by Figure 4, the washer 16 can be of very simple annular form. In use, the head 17 of the screw 13 presses down on the plate 10 so that the washer 16 is compressed between the plate 10 and the sheet 11 as shown by Figure 3.

Figure 5 is an enlarged view showing the way in which the plate bears down on the crown surface 18 of a rib 19 of the sheet 11. As will be evident from Figure 5, the under surface 20 of the plate 10 is formed so as to have a flatter curvature than that of the crown surface 18, with the result that *..the engagement between the surfaces 18 and 20 is confined to a region 21 between the two lines 22 as shown by Figures 5 and 6. At least, such confinement will exist when the sheet 11 is not subjected to load. In the :*)particular example shown, the region 21 extends between opposite ends 23 (Figure 6) of the plate The arrangement is such that a clearance space 24 (Figure 5) exists on each side of the pressure region 21. Each clearance space 24 preferably :')increases from zero depth at or adjacent a respective one of the region "o boundaries 22, to maximum depth at or adjacent a respective one of the side edges 25 of the plate 10. When the sheet 11 is subjected to wind or other loading it will tend to flex at the region 21 so as to move upwards on each side of that region and thereby progressively remove part or all of each clearance space 24. That is unlikely to create permanent distortion or deformation of the sheet 11, and consequently the sheet 11 will return to the configuration shown by Figure 5 when the relevant load is removed.

The plate 10 can be formed of metal or any other suitable material, and can have a peripheral shape different to that shown by Figure 6.

Figures 7 and 8 show a plate 10 according to another embodiment of the invention and which is designed for use with square ribbed sheet 11. The relationship between the surfaces 18 and 20 is as described in relation to the embodiment of Figures 3 to 6. Also, the washer 16 may be of the same form as that shown by Figure 4.

C:\WINWORDISHAROMANDREWtPROVS%518013.DOC P:\OPER\RSHU422072.spe.doc-29/01/02 -7- Figure 9 shows yet another form of plate 10 which is designed for use with substantially flat sheet material 11. In this arrangement the plate under surface is convex rather than concave as in the previously described embodiments. Also, the clearance space 24 may extend completely around the central region of the plate 10 as shown in Figure 9.

Although the specific shape of the plate 10 varies in each of the embodiments in accordance with the type of sheet material for which the plate is designed to be used, nevertheless it will be appreciated from the drawings that in each embodiment the plate has a dished shape when considered in transverse 10 cross-section, the depressed side thereof either facing towards the sheet material *so: or away from the sheet depending on the form of the sheet material to provide the effects described. It will be noted from the drawings, that in each of the embodiments described, the plate is of substantially constant cross section along its length apart from the zone of the opening 14 and associated cavity 15 It will be apparent from the foregoing description that a load bearing plate according to the invention has several benefits. The plate can be used with a resilient sealing washer of simple and inexpensive form. Also, when used in a sheet fixing installation the plate significantly reduced the risk of the sheet being permanently distorted under high load conditions. Still further, the nature of the 20 plate is such that the incidence of incorrect installation is minimised, and incorrect installation is unlikely to have serious adverse consequences.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.

Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

Claims

1. A load bearing plate for securing sheet material to a support, said plate being intended to overlie said sheet material and having an opening for receiving a fastening screw and an under surface of a contour which is different to the contour of the surface of the sheet material which the plate is intended to overlie, said difference in contour being such that under normal conditions of use (as hereinbefore defined), said plate bears on said sheet material in a 06 region adjacent said opening and a clearance space exists between said plate 0 10 and said sheet material outwardly of said region, said plate being of dished shape 00 0* in transverse cross-section. 0 *SO

2. A load bearing plate according to claim 1, said plate having an under surface contour such that said clearance space progressively increases from a minimum adjacent said region, to a maximum at the outer periphery of said plate. 000

3. A load bearing plate according to claim 1 or 2, said plate having an under surface contour such that said clearance space extends completely around said bearing region. oo 4. A load bearing plate according to claim 1 or 2, said plate having an under surface contour such that said clearance space extends from opposite sections of said opening and said bearing region extends in a band from opposite sections of said opening which are generally perpendicular to said opposite sections from which said clearance space extends. A load bearing plate according to any one of claims 1 to 4, said plate including a cavity formed below said opening for receiving a resilient sealing member to seal between said under surface and the surface of the sheet material which the plate is intended to overlie. CI'_ 'PRW OI"''3 OC

6. A load bearing plate according to claim 5, said cavity being of frusto-conical configuration.

7. A load bearing plate according to any one of claims 1 to 6, said under surface contour being generally concave.

8. A load bearing plate according to any one of claims 1 to 6, said under oooo surface contour being generally convex.

9. A load bearing plate according to any one of claims 1 to 8, said plate being formed in a metallic material. o0oo A load bearing plate according to any one of claims 1 to 9, said plate being generally square or rectangular in plan view. o 11. A fastening system for securing sheet material to a support, said system including a load bearing plate arranged to overlie said sheet material and having an opening therethrough, a fastening screw passing through said opening and said sheet material and threadably engaging said support, the .o under surface of said plate facing said sheet material having a contour such that said plate bears against said sheet material in a region adjacent said opening and a clearance space exists between said plate and said sheet material outwardly of said region, said plate being of dished shape in transverse cross-section.

12. A fastening system according to claim 11, said clearance space progressively increasing from a minimum adjacent said region, to a maximum at opposite sections of the outer periphery of said plate.

13. A fastening system according to claim 12 or 13, wherein said sheet aterial is generally corrugated or square ribbed and said plate is fixed by said fastening screw to the crown under surface of a rib of said sheet material, the under surface of said plate facing said sheet material having a generally concave contour of flatter curvature than said crown surface.

14. A fastening system according claim 12 or 13, wherein said sheet material is generally flat and the surface of said plate facing said sheet material has a generally convex contour relative to said sheet material. 10 15. A fastening system according to any one of claims 11 to 14, wherein a resilient sealing member is positioned between said plate and said sheet material about said plate opening.

16. A fastening system according to claim 15, said plate including a cavity below said opening for receipt of said resilient sealing member.

17. A fastening system according to claim 16, wherein said cavity is frusto- conical.

18. A fastening system according to any one of claims 15 to 17, said resilient 0 sealing member having an annular form. Cfl swworMiAROiANoaeWPovl15a,3 00: P:,OPER\RSH\2422072.spe.doc-30D 1/02 -11-

19. A fastening system for securing sheet material to a support in conditions where the sheet material may be exposed to a high wind loading such as to cause the sheet material to flex, said system including a load bearing plate arranged to overlie the sheet material and having an opening therethrough, the plate being of dished shape in transverse cross-section, and a fastening screw passing through the opening and the sheet material to engage the support, the under surface of the plate facing the sheet material having a contour such that the plate bears against :o the sheet material in a region adjacent the opening and a clearance exists between the plate and said sheet material outwardly of said region, the clearance 06 space progressively increasing from a minimum adjacent said region to a maximum at opposite sections of the outer periphery of the plate such that when the sheet material is subject to a high wind loading which causes the sheet material to flex about said region, the sheet material will lift into the clearance space with a consequent progressive increase in the surface area of the sheet 15 material which presses against the overlying load bearing plate. "So:*

20. A fastening system according to claim 19, wherein a resilient sealing member is positioned between the plate and the sheet material about the plate opening. o

21. A fastening system according to claim 19 or claim 20, wherein the plate is generally square or rectangular in plan view.

22. A fastening system according to anyone of claims 19 to 21, wherein apart from the zone of the plate having the opening therethrough, the plate is of substantially constant transverse cross-section along its length.

23. A load bearing plate substantially as herein described with reference to Figures 3 to 9. P:WOER\RS HU 422072 ,pcdo.-3/OI/02 12

24. A fastening system substantially as herein described with reference to Figures 3 to 9. DATED this 3 0 th day of January 2002 W.A. Deutsher Pty Ltd 0:00 By DAVIES COLLISON CAVE e00. Patent Attorneys for the applicant