AU680319B2 - Fastener retention - Google Patents

Description

I-

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Application Number Lodged Class Int. Class Complete Specification Lodged Accepted Published Priority: Australian Provisional Patent Application No. PM3376 dated 14 JANUARY 1994 Related Art: Applicant's Ref: Applicant: STRAMIT CORPORATION LIMITED 00 0.600: 0 9 .00.

0 0* *0 0 Actual Inventor(s): Address for Service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 VIC AUSTRALIA Complete Specification for the invention entitled: FASTENER RETENTION ,0o Our Ref: IRN 383970 The following statement is a full description of this invention, including the best method of pt.rforming it known to applicant: RNC/383S70A.DOC I ~'lr sseir~ ~PIIPI~ -2- FASTENER RETENTION S.

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The present invention relates to the retention of screw fasteners in metal anchor members, such as metal sections. The invention finds particular application in the context of securing screws into metal anchor members comprising metal roofing battens, to ietain roofing sheets in relation to the battens, and is described here in that context. However, the invention also can be used similarly to retain wall sheeting in relation to wall battens or studs, while it is to be appreciated that the invention has still broader application.

A typical prior art metal roofing batten is of channel form, defining a generally top hat cross section, roll-formed from sheet metal of a base metal thickness (BMT) as low as 0.4mm. That is, the batten has two opposed, longitudinal side walls, an outturned flange at the lower edge of each side wall, and a web or crown joining each upper edge of the side walls. In use, the side flanges are secured to the roof structure. A roofing sheet is then secured to the batten by screws, usually of the self-drilling type, inserted through the roofing sheet and penetrating the crown of the batten. To prevent slippage of fasteners on the crown top surface during installation, and also to provide additional strength to the batten, the crown may be knurled to form a series of shallow 20 crests and valleys.

The present invention aims to provide an anchor member, such as a roof batten, which provides an increase in the strength of the fastener connection into the anchor member, such as in the crown. In the case of a batten, the strengthened fastener connection can increase the resistance to wind uplift on .25 roofing sheets.

The present invention is characterised by the provision of a metal anchor member which has an anchor portion by which it is attachable to a support structure and, integral with the anchor portion, an attachment portion by which a component can be secured in relation to the support structure by means of a fastener having a threaded, serrated or circumferentially ribbed shank engageable through the component and the attachment portion. In the anchor member of the invention, the attachment portion is provided with at least one *5

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-3flute or groove having opposed walls with which the threads, serrations or ribs of the fastener shank engages.

In a variety of applications, the anchor portion and the attachment portion may be adjacent and, in such case, they typically are mutually inclined, such as at right angles. The anchor member may be in the form of an L-shaped bracket or it may be of elongate form and have an L-shaped cross-section. In some applications, the anchor portion and the attachment portions may be spaced by a spacer portion therebetween, such as in the form of a Z-shaped or C-shaped bracket or an elongate bracket of Z- or C-shaped cross-section.

In another form, the anchor member may have two anchor portions with which the attachment portion is integral. The anchor portion may be adjacent to and spaced by the attachment portion, with the member being of U-shape or of an elongate form of U-shaped cross-section. In a variant of this form, each 0% 15 anchor portion may be spared from the attachment portion by a respective spacer portion. A batten according to the invention is an example of an elongate anchor member according to such variant in which relative to the batten described above, the attachment portion comprises the crown, each spacer portion comprises a side wall and each anchor portion comprises an 20 outwardly turned flange.

The anchor member of the invention can be formed of a suitable metal by any suitable cold forming operation. Thus, they can be formed from sheet metal, such as by stamping, bending operations, rolling, or by any other cold forming operations. The anchor member preferably is formed by cold forming or cold rolling of steel sheet, such as high tensile steel sheet, but other metal sheet such as of aluminium alloy, copper or copper alloy can be used in at least some applications.

The attachment portion may have only a single flute. However, it preferably has a plurality of adjacent flutes enabling a selected one to be utilised in a given in use situation Most preferably, at least the attachment portion is such that the flutes are in the form of corrugations of substantially uniform wall thickness between each of opposite surfaces thereof. In general terms, the flute or flutes can extend in any suitable direction. However, in the -4case of an elongate member such as a batten, the flute or flutes preferably extend longitudinally, either continuously or along selected parts of the length of the member.

The fastening means may comprise screws, such as self-drilling screws, However, they can comprise other forms of fasteners, such as nails having serrated or circumferentially ribbed shanks. The fastening means most preferably are in accordance with an accepted standard or specification, with the flute or flutes with which they are to be used having a width between their opposed walls such as to be engaged by the thread, serrations or ribs of the fastening means. However, the fastening means can be specifically designed for use with a given anchor member for which that width of flute or flutes provides suitable engagement.

The flute or flutes may have parallel opposed walls. However, those walls may be inclined slightly so as to converge in an intended direction of :I 15 application of the fasteners.

:When self-tapping screws are used, they of course can form openings through the material of the attachment portion where they are applied or secured. The same can occur with other forms of fastening means. However, if required, longitudinally spaced dimples or indentations can be provided along 20 the centre-line of the or each flute, from the surface of the attachment portion from which the fastening means are applied, to assist in achieving perforation of the attachment portion by the fastening means.

The anchor member can be of any suitable thickness and, as indicated, it can be formed of sheet metal. In the case of an anchor member comprising a 25 batten, for use in a roofing or wall structure, but also for anchor members for many other applications, the member may have a BMT of from about 0.3 to about 0.53mm. The BMT preferably is from about 0.38 to about 0.45mm, such as about 0.4mm. The anchor member preferably is of a suitable steel, such as a high tensile steel.

The or each flute preferably is of a uniform cross-section. However, the actual width and depth of the or each flute can vary, depending on the application for the anchor member and, in part, also on the number of flutes and the thickness of the anchor member. In general, the flutes can have a L s I depth of from about 3 to 15mm, although the depth preferably is from about 4 to such as about 4 to 6mm.

In general, the flutes have a width which is similar to or less than the depth. However, a factor relevant to both the depth and width of the flutes is the nature of the fastener to be used with the anchor member, such as the diameter of the fastener and the pitch of the thread or longitudinal spacing between serrations or ribs of the fastener.

Where, for example, a flute has parallel side walls and the fasteners comprise screws, such as self-drilling screws, the depth and width of the flute preferably are such as to accommodate a suitable fastener so that at least two threads of the screw engage the side walls above the base of the flute.

Depending on whether the screw has a coarse or fine thread, the arrangement may be such as to enable up to six or more threads to engage the walls.

Usually, there is likely to be limited further benefit in having more than ten 15 threads engage the side walls. Similar considerations apply to serrated or ribbed fasteners, the reference to the number of threads in the case of screw fastenings corresponding to the number of serrations or ribs of other fasteners.

The matters of the immediately preceding paragraph herein generally are applicable to flutes with mutually inclined side walls. Again, the 20 arrangement is such that two threads, serrations or ribs engage each side wall.

S However, subject to the ability of the material, of which the anchor member is made, to deform at the side walls, it can be difficult in general to have more S* than four to six threads, serrations or ribs engage the side walls.

As will be appreciated, reference herein to a number of threads is to 25 successive turns of the thread or threads.

Relative to an intended fastener for a given anchor member with parallel flute side walls, the spacing between those walls is to be less then the major diameter of the fastener. That is, the spacing is to be less than the diameter of the threads in the case of a screw, and less than the diameter set by serrations or ribs in the case of other forms of fasteners. The arrangement is to be such that the threads, serrations or ribs positively engage the side walls and, for this, the spacing between the wide walls may be at least 5% less than the major diameter, but preferably is at least 10% less than the major diameter. Most preferably, the spacing is at least 20% less than the major diameter.

The spacing may be less than the minor diameter of the fastener, that is, of the diameter of the fastener shank at the root of the threads, serrations or ribs. However, subject to the ability of the material of the anchor member to deform at the side walls, it generally is desirable for the spacing between the I side walls not to be less than about 90% of the minor diameter. Somewhat similar considerations apply where the side walls are mutually inclined, except that the average spacing between those walls needs to be considered. Also, with such inclined walls, it generally, is not desirable for the inclination to be excessive, with an included angle of not more than 150 to 200 being preferred.

Reference is made to the BMT of the anchor member. However, the anchor member may have a galvanised, zincalume or plastics coating. In such case, it generally is appropriate to have regard to the spacing between coated 15 surfaces of the side walls of a flute, as the engagement between the fasteners and the side walls can be with or in the coating or, by deforming the coating, at least partly through the coating to engage the base metal.

In order that the invention can be more readily understood, description is now directed to preferred embodiments shown inn the accompanying drawings, 20 in which: Figure 1 is a schematic vertical section of a roofing system having a Preferred roofing batten according to the invention; Figure 2 is a more detailed schematic cross-section of the system of Figure 1; 25 Figure 3 is a schematic cross-section similar to Figure 2, showing a second embodiment of the invention; and Figure 4 is similar to Figure 1, but shows a variation possible.with thei present invention.

In Figure 1, a roofing system 10 includes a parallel array of rafters 12 of i a roof frame, with only part of one rafter 12 visible. Secured across rafters 12, there is a parallel array of battens 14, of which only one is shown. Roofing decking represented by sheeting 16 is secured to battens 14.

r: -7- Each batten 14 is formed from sheet metal ,such as of roll-formed steel sheeting of substantially uniform 0.4, BMT. As shown, each battens 14 have opposed sir' 'ails or webs 20 each of which has an outwardly turned flange 22 at its lowe, edge. Walls 20 converge at a slight angle to the vertical and are joined at their upper edges by a crown 24 of batten 14.

Each batten 14 is secured across rafters 12 by respective screws 26 passing through each flange 22 into each rafter 12. Sheeting 16 is then laid on battens 14 and secured by self-drilling screws 28 passing into the crown 24 of respective battens 14.

The crown 24 of each batten 14 is rolled to a form in which it defines a respective shoulder 30 which extends inwardly from each wall 20. The shoulders 30 provide positive support for sheeting 16 as the latter is clamped onto crown 24 with tightening of screws 28. Between the shoulders 30, crown 24 is rolled to a corrugated form to define longitudinal flutes 32. Each flute 32 15 has opposed, substantially vertical side walls 32a which are spaced apart by a distance slightly less than the thread diameter of screws 28. Also, each flute 32 ass has a base 32b and crests 32c which are curved in cross-section, to provide a ass* smooth continuation between successive walls 32a.

As a screw 28 penetrates sheeting 16, its leading end enters between 20 the walls of 32a of an aligned flute 32, or is guided by a crest 32c so as to align ii S with a flute 32. On further application of the screw 28, it passes through the flute 32, and penetrates its base 32b. As a minimum, the walls 32a of the flute 32 are spaced by a distance slightly less than the thread diameter of screws 28, so as to resiliently engage the thread of the screw 28 and resist the tendency 25 for the latter to loosen. However, more typically, the thread of screw 28 bites into walls 32a arid this, in combination with the resilience of the metal of batten 14, results in screw 28 being firmly engaged.

Figure 2 shows a somewhat schematic representation of engagement of a screw 28 in a flute 32 of batten 14 of Figure 1. As shown in Figure 2, the thread of screw 28 has deformed walls 32a, by biting into those walls as screw 28 is driven down into the flute 32. Typically, screw 28 will be harder than the stee' used for fabrication of the batten 14, to enable this form of engagement.

However, the resilience of the side walls 32a enhances and retains the -8engagement, while the curved form of the crests 32c and base 32b of each flute 32 can provide strengthening which assists in maintaining resilient engagement. Additionally, the side walls 32a may locally deform, plasticly outwardly, by the action of tie threads of the screw and this can further assist in maintaining resilient engagement. Also, depending on the spacing between walls 32a relative to the thread diameter of screw 28, the deformation of walls 32a may be only or partly in a protective surfacing over batten 14, such as a surfacing provided by a galvanised coating.

In Figure 2, and also in the other illustrated embodiments, the required engagement between the side walls 32c and the fastener is due at least in part to the resilience of the side walls. However, as shown, for example, in Figure 2, the engagement can be enhanced by the fastener thread (or serrations or ribs with other fastener types) biting into the side walls. Si ilch biting of the side walls, which can be akin to a partial threading of their surfaces on application of 15 the fastener, can itself at least in part be attributed or result from the resilience iof the side walls.

The arrangement of Figure 3, which shows only part of the detail of Figure 1, differs in that walls 32a of each flute 32 converge downwardly towards its base 32b. This can provide further strengthening of engagement between 20 walls 32a and screw 28. The required spacing between walls 32a for S engagement by the thread of screw 28 needs to commence upwardly of base 32b, such as at about the mid-height of flute 32 or higher. As screw 28 is driven into the flute 32, the engagement force increases and necessitates more extreme deformation of walls 32a. Also, as the leading end of screw 28 25 approaches base 32b of the flute 32, deformation of walls 32a is resisted by the base 32b, further increasing resultant engagement forces acting to retain screw 28 once it is fully applied.

Figure 4 shows a variant of the arrangement of Figure 1. in this, that comprising each shoulder 30 in Figure 1 is defined by an outermost crest 32c.

Also, the thickness of the sheet metal, of which batten 14 is formed, is such that the crown 24 tends to bow downwardly on fixing sheeting 16 by means of screws 28. As a consequence, the upper extent of walls 32a are flexed morestrongly into engagement with screw 28. Also, wind forces tending to lift -9sheeting 16 will tend to return crown 24 to its original unflexed, initial position and, while this will reduce engagement forces between the upper extent of walls 32a and screw 28, it also will act to increase engagement forces bet .3en the lower extent of walls 32a and screw 28.

Thus in each of Figures 1 to 4, each screw 28, after passing through the sheet 26, will self-engage into the most convenient flute 32 and will be guided to pass down the flute 32 with the thread engaging the opposed side walls 32a as well as penetrating through the base 32b of the flute 32. This provides extra grip between the thread of each screw 28 and the batten 14, thus increasing the fastener retention strength. The wind uplift force required to rip the screw 28 out of the crown 24 of a batten 14 is increased, leading to more secure fastening of the roofing sheet 26.

The depth of the flute 32 is preferably sufficient to allow engagement of the thread of screws 28 with the side walls 32a over a length of at least several 15 times the thread pitch. In the illustrated batten 14, the flutes 32 may be about deep.

The illustrated batten constructions may also be used as a ceiling batten.

Also the principle of the invention is applicable to other metal sections, and particularly to roll-formed sections, where use of the invention allows an 20 increase in fastener retention strength without the need to increase the metal gauge over the entire section. For example, the invention may be used for metal framed house construction.

In the context of an understanding of the embodiments of Figures 1 to 4, other variants of the invention readily will be able to be understood. A number 25 of variants of the invention now will be detailed.

SIn each of Figures 1 to 4, it will be appreciated that batten 14 is of elongate form, and has a substantial length in a direction perpendicular to the plane of each Figure. However, in a first variant, suitable for some applications where sheet material is to be attached to a support, the anchor means may be similar to batten 14 but quite short in that direction. Thus, the dimension in that direction may, for example, by similar to the width of crown 24, with the anchor member being in the form of a saddle-shaped bracket.

~s In a further variant, the anchor member may be of elongate form, and have a cross-section similar to batten 14 except that it has is only one side wall so as to be of Z-shaped cross-section. In a further variant, the anchor member may be short, rather than elongate, and comprise a Z-form bracket.

In a further variant, the anchor member may be elongate and similar to a batten 14 in having walls 20 and crown 24, but have no flanges 22. In a still further variant, the anchor member may be similar to a batten 14 in having one wall 20 and a part corresponding to crown 24, with the one wall 20 note having a flange 22. Also, non-elongate brackets corresponding to each of these variants are possible.

In battens 14, and each of the elongate variants, the flutes 32 may be continuous throughout the length of the anchor member. However, in each case, the flutes may extend along only successive longitudinally spaced parts of the length of the anchor member. Also, while battens 14 have longitudinal 15 flutes, as is preferred for ease of products, the flutes in battens 14 and in elongate variants may extend laterally of crown 24 and the corresponding part of each variant. Similarly, the direction of flutes in non-elongate anchor members may extend in a direction which corresponds to such lateral flutes.

In battens 14, flutes are provided only on crown 24. However, in at least 20 some elongate and non-elongate variants, a respective set of flutes may be provided on each of a part corresponding to crown 24 and on a part corresponding to a side wall 20 and/or a flange 22. An arrangement illustrating the provision of respective sets of flutes is that of an elongate anchor member 4 of L-section which is to inter-connect two mutually inclined sheeting members at 25 adjacent edges. Such L-section member may have longitudinal or lateral flutes formed in each of its flanges.

With each of Figures 1 to 4, battens 14 are formed of sheet metal.

However, in at least some variants, the anchor member of the invention can be formed of a suitable plastic material.

In each of Figures 1 to 4, sheeting 26 is shown as comprising substantially flat decking. However, as will be appreciated, sheeting 26 can be ribbed or corrugated.

-11 In the invention as illustrated by reference to Figures 1 to 4, the flutes are taken as opening towards the component to be secured. Also, the or each fastener is shown as applied through the component so as to enter a flute, and then pass between the opposed walls of the flute prior to penetrating the base of the flute. However, alternative arrangements are possible. Thus, the or each fastener can penetrate the crest of a flute and then enter the flute to engage the side walls of the flute. Also, with either arrangement, the or each fastener can be applied first through a flute and thereafter through the component, although this, of course, generally will not be appropriate where the anchor member is a batten and the component is roofing or wall sheeting.

In this invention, as illustrated by reference to the drawings, the or each flute is shown as of part-sinusoidal or corrugated form in which it has a curved base and curved crests. This generally is the most practical form, particularly where the anchor member is elongate and produced by a roll forming or 1F bending operation or sheet metal. However, an alternative arrangement is possible, in that the base of each flute can be substantially flat, with the inlet to each flute defined between two oppositely extending substantially flat lands.

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 20 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 and not restrictive,, all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

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Claims (29)

1. A metal anchor member having an anchor portion by which it is attachable to a support structure and, integral with the anchor portion, an attachment portion by which a component can be secured in relation to the support structure by means of a fastener having a threaded, serrated or circumferentially ribbed shank engageable through the component and the attachment portion; the attachment portion being provided with at least one flute or groove having opposed walls with which the thread, serrations or ribs of the fastener shank engages.

2. A member according to claim 1, wherein the member is formed from sheet metal by a cold forming operation.

3. A member according to claim 2, wherein the anchor and attachment portions are adjacent and mutually inclined. 15

4. A member according to claim 3, wherein the member is in the form of an **i i L-shaped bracket or is of elongate form of L-shape cross-section.

A member according to claim 1 or claim 2, wherein the anchor pcrtion and the attachment portion are spaced by a spacer portion therebetween.

6. A member according to claim 5, wherein the member is in the form of a 20 Z- or C-shaped bracket or is of elongate form of Z- or C-shape cross-section.

7. A member according to claim 1 or claim 2, wherein there are two anchor portions each spaced from a respective one of opposed sides of the attachment portion by a respective spacer portion.

8. A member according to claim 7, wherein the member is in the form of a 25 saddle or U-shaped bracket or is of elongate form of U-shape cross-section.

9. The member according to claim 8, wherein each anchor portion extends outwardly with respect to its spacer portion, away from the other anchor portion.

A member according to any oJrn of claims 1 to 9, wherein the attachment portion is provided with a plurality of flutes or grooves.

11. A member according to any one of claims 1 to 10, wherein the opposed walls of the or each flute or groove are substantially parallel and engagement of the walls by the thread, serrations or ribs at least partially results from the resilience of the side walls. -13-

12. A member according to any one of claims 1 to 10, wherein the opposed walls of the or each flute or groove converges slightly in a direction of intended application of the fastener and engagement of the walls by the thread, serrations or ribs at least partially results from the resilience of the side walls.

13. A member according claim 8 or claim 9, or to any one of claims 10 to 12, when appended to claim 7 or claim 8, wherein the member is of elongate form and comprises a batten suitable for use in a roofing system.

14. A member according to claim 13, wherein the or each flute or groove extends longitudinally along the attachment portion thereof.

15. A member according to claim 1, substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings, or to Figures 1 and 2 as modified in accordance with Figures 3 or 4 of those drawings.

An attachment system, providing securement of a component to a support structure, the system including an anchor member according to any 15 one of claims 1 to 14, wherein the anchor portion of the anchor member is attached to the support member and the component is secured in relation to the support structure by at least one fastener having a threaded, serrated or 1 circumferentially ribbed shank engaged through the component and the ii attachment portion, and wherein the shank of the fastener extends into the or a Io: 20 flute or groove of the attachment portion so as to project through a base or :.crest thereof, with the opposed walls of the flute or groove engaged by the thread, serrations or ribs at least partially due to the resilience of the side walls.

17. A system according to claim 16, wherein the anchor member is of elongate form, the component abuts at least part of the longitudinal extent of the attachment portion and the component is secured by a plurality of fasteners ii spaced along the anchor member.

18. A system according to claim 17, wherein there is a plurality of flutes or grooves of which at least one is used in securing the component by said fasteners.

19. A system according to claim 17 or claim 18, whierein said anchor member comprises a batten, the support structure comprises a roof or wall frame structure, and the component comprises roof or wall sheeting.

I -L I I LI -C -I sl -14- A system according to any one of claims 17 to 19, wherein the or each flute or groove extends longitudinally over at least part of the length of the attachment portion.

21. A system according to claim 19 orto claim 20 when appended to claim 19, wherein the anchor member has two anchor portions each spaced from a respective side edge of the attachment portion by a respective side wall of the batten.

22. A system according to any one of claims 16 to 21, wherein the or each flute has a depth of from 3 to

23. A system according to claim 22, wherein said depth is from 4 to

24. A system according to any one of claims 16 to 23, wherein the or each flute has a width which is similar to or less than the depth thereof.

A system according to any one of claims 16 to 24, wherein each flute side wall engaged by the or a fastener is engaged by from 2 to 10 thread turns, 15 serrations or ribs of the fastener. @oo i:i

26. A system according to claim 25, wherein the engagement is by trom 2 to 6 thread turns, serrations or ribs.

27. A system according to any one of claims 16 to 26, wherein the or at least one fastener is applied so as to enter between the side walls of the respective 20 flute prior to penetrating through the attachment member. S

28. A system according to any one of claims 16 to 26, wherein the or at least one fastener is applied so as to penetrate through the attachment member prior Go": to entering between the side walls of the respective flute. S..

29. A system according to any one of claims 16 to 28, wherein the or each 25 fastener is applied so as to penetrate through the component prior to S• engagement with the respective flute. Dated: 16 January, 1995 STRAMIT CORPORATION LIMITED la';aA4 6 r" t1c By their Patent Attorneys PHILLIPS ORMONDE FITZPATRICK RNC/1rn383970.do 1 -I c-, I l ABSTRACT A metal member having an anchor portion by which it is attachable to a support structure and, integral with the anchor portion, an attachment portion by which a component can be secured in relation to the support structure by means of a fastener having a threaded, serrated or circumferentially ribbed shank engageable through the component and the attachment portion. The attachment portion is provided with at least one flute or groove having opposed walls with which the thread, serrations or ribs of the fastener shank engages. An attachment system providing securement of a component to a support structure includes the anchor member. The anchor portion of the anchor member is attached to the support member and the component is secured in relation to the support structure by at least one fastener having its shank engaged through the component and the attachment portion. In the system, the shank of the fastener extends into the or a flute or groove *:Poo: of the attachment portion so as to project through a base or crest thereof, with the opposed walls of the flute or groove engaged by the thread, serrations or ribs at least partially due to the resilience of the side walls. 0 V I,' o so^- S l ll 0 S* 005000'--;, 'S S 4