GB2426011A

GB2426011A - Insulating and fastener aligning foot cover for roof support bracket

Info

Publication number: GB2426011A
Application number: GB0509780A
Authority: GB
Inventors: Francis Bryan Carey
Original assignee: Ash and Lacy Building Systems Ltd
Current assignee: Ash and Lacy Building Systems Ltd
Priority date: 2005-05-13
Filing date: 2005-05-13
Publication date: 2006-11-15
Anticipated expiration: 2025-05-13
Also published as: GB2426011B; GB0509780D0

Abstract

An insulating and fastener aligning cover 6 for the foot 3 of a bracket 1 for supporting a roof support bar via its head 2 comprises a sole portion 13 adapted to be disposed between foot 3 and an underlying support structure, and a fastener alignment tongue portion 8 spaced from but connected to sole portion 13 by hinge means 9 and having apertures for receiving and aligning fasteners 4 prior to being driven in.. As shown in Figure 3, as the fasteners, e.g. screws, are driven in to the underlying structure, e.g. an existing root cover 6 collapses about hinges 9, which may be living hinges, whilst maintaining fastener alignment.

Description

I

Improvements in and relating to Wall and Roofing Structures This invention relates to roofing structures, which expression also includes wall structures, comprising a weather-proof membrane supported on a grid of membrane support bars which are themselves supported by and spaced from a primary structural member, such as an existing roof structure, by a plurality of spaced apart support bar brackets.

In GB 2148975 there is described a roof/wall assembly in which the support bracket is designed to "twist and lock" into the support bar. An improvement to this concept is described in GB2240558 wherein the support bracket is adapted to instead be aligned with the major axis of the support bar and then levered up from an angled position to an upright position with respect thereto so that it cannot rotate about the vertical axis relative to a horizontally disposed bar. In each case, the space between the roofing membrane and the primary structure, which itself may typically be an existing roof membrane and supporting structure is filled with an insulating material such as fibreglass or rockwool and in order to increase thermal efficiency a thermal break is typically used between the respective bars and brackets. In the case of the invention described in GB2148975 this takes the form of a plastics cap overlaying the head of the bracket between it and the roof membrane support bar and in the case of GB2240558 there is instead typically used a foam pad secured to the underside or sole of the foot of the bracket, thereby acting as a thermal break between the bracket and the primary structural member, as well as a seal preventing leakage of air or water.

A known problem with such bar and bracket grid roofing systems is that at final assembly and installation they rely upon often-unsupervised and low skilled site labour and poor working site conditions such that the screwthreaded fasteners used to secure the brackets to the primary supporting structure may not be properly axially aligned relative to the foot of the bracket, particularly where the bracket, including the foot, are corrugated or otherwise non-planar so as to increase stiffness. In such circumstances, if a fixing screw is not aligned and installed in the required design position then unbalanced forces and pressures can result, particularly given that such brackets are of ever-increasing length so as to comply with increasing insulation obligations under the Kyoto agreement. Such misalignment of the fixing screws can therefore lead to a lowering of the overall strength of the roofing grid structure and possible distortion of the thermal break/seal between the foot of the bracket and the primary support structure. The former can lead to catastrophic structural failure and the latter to leakage of air and water.

According to the invention there is provided a combination fastener alignment and insulating foot cover for the foot of a roof/wall bar support bracket, the roof/wall bar being of the type in which a grid of such bars are supported by a plurality of such brackets on a primary support structure, and onto which grid can thereafter be fixed a roof/wall membrane, the foot cover comprising a lower, insulating, sole portion adapted to be disposed, in use, between the foot of the roof/wall bar support bracket and the primary support structure on which the bracket is to be fixed, and an upper fastener alignment tongue portion spaced from but connected to said sole portion by hinge means and including fastener receiving and fastener alignment apertures for receiving fasteners therein in a required alignment orientation prior to being driven into said primary support structure.

Conveniently, the combination foot cover is integrally moulded from plastics and includes at least a pair of fastener receiving and alignment apertures, adjacent to each of which is a living control hinge allowing the tongue portion to collapse onto the top of the foot of the bracket when the fasteners are driven into the primary support structure. On that portion of the tongue remote from the living control hinge and fastener receiving apertures there may be ribs depending therefrom such that as the tongue collapses onto the top of the foot of the bracket when a respective fastener is driven into the primary support structure its respective rib compensates for any distortion which may otherwise be caused by the compressed material around the living hinge.

Advantageously, the upper surface of the sole portion is shaped to follow the profile of the lower surface of the foot of a roof/wall bar support bracket and the lower surface of the sole portion is substantially planar. This is particularly advantageous because it maximises the surface area between the insulating foot cover and the primary support structure which, in turn, helps to prevent or inhibit "wander" of the fastener as it is being driven into the underlying support structure, which is typically an existing metal roof structure.

Conveniently, the foot cover also includes bracket edge receiving formations allowing the cover to be slideably receivable on the foot portion of a respective bracket.

As will be apparent, the combination fastener alignment and insulating foot cover for the foot of a roof/wall bar support bracket may be supplied as a separate item, although it conveniently lends itself to pre- assembly with the bracket and associated fasteners and, accordingly, the invention also extends to the combination of a roof/wall bar support bracket, onto the foot of which is secured a fastener alignment and insulating foot cover which includes fasteners, such as a pair of screw- threaded fasteners, driven therein but not therethrough such that upon placement of the bracket within a roof/wall bar and being positioned onto a primary support structure no separate step is required on site to ensure correct alignment of the fasteners relative to the foot of the bracket but instead such fasteners simply need to be driven into the primary support structure. A further advantage is that such pie-assembly ensures that the correct specification and number of such fasteners to suit the type of primary support structure is used, typically two screw threaded fasteners, thereby avoiding the possibility of inferior fasteners being used and fewer in number than is required for securely fixing the bracket to the primary support structure.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which, Figure 1 is a perspective view of a combination fastener alignment and insulating foot cover mounted on the foot of a roof bar support bracket, Figure 2 is a front view of the foot cover and the lower part of the bracket of Figure 1, and Figure 3 is a front view of the foot cover and the lower part of the bracket of Figure 1 but showing the foot cover in its final, collapsed, condition, Referring to the drawings, there is shown a roof bar support bracket I of the type described in GB2240558 which includes a head portion 2 intended to lockingly engage with a generally "L" shaped roof bar (not shown) and a foot portion 3 for placement upon and fixing to a primary support structure (not shown), such as an existing metal roof structure, by a pair of threaded fasteners 4 having drill-type tips 5 (shown in Figure 2) by which they may be self- drilled and tapped into e.g. an existing metal roof structure.

The arrangement thus far described is conventional but in accordance with this embodiment of the invention there is provided a combinatiàn fastener alignment and insulating foot cover shown generally at 6 which includes a, lower, insulating sole portion 7 and an, upper, fastener alignment tongue portion 8 spaced from but connected to the sole portion 7 by living hinges 9 acting to control the axial alignment of the fasteners 4 as they are being driven in, in the manner to be described with reference to Figure 3.

The tongue portion 8 includes a pair of fastener receiving recessed apertures 10 (shown in Figure 2) which are adapted to hold the fasteners 4 in their correct axial alignment relative to the foot 3 of the bracket I and adjacent to each such alignment aperture 10 is a respective rib 11 depending from the tongue portion 8.

The foot cover 6 also includes bracket edge receiving formations in the form of oppositely disposed channels 12 for receiving edges of the foot 3 of the bracket I so as to ensure correct alignment of the fasteners 4 relative to access holes (not shown) in the foot 3 of the bracket I through which the drill tips 5 of the fasteners 4 may be inserted to ensure correct alignment therewith prior to being driven into the primary support structure on which it rests.

As will be apparent from Figure 3, when the fasteners 4 are driven into an underlying support structure such as an existing metal roof, the tongue portion 8 will collapse at its edges towards the foot portion 3 of the bracket 1, the living control hinges 9 allowing for this and the ribs 11 compensating for the compressed material thereafter present in the region of the living hinges 9 to thereby angularly stabilise the thus compressed structure in this region. In so doing, the tongue 8, after initially acting as a means to stabilise the alignment of the fasteners 4 thereafter acts as a second thermal break and water/air seal to the sole portion 7. The sole portion 7, in being shaped to follow the profile of the foot 3 of the bracket I but whilst having a planar lower surface 13 is therefore effectively keyed into the foot 3 and hence bracket I such that as each fastener 4 is driven into the underlying primary structure there is a reduced tendency for the fasteners 4 to "wander" by skidding along the top of the underlying support structure when being driven in, particularly where the fasteners 4 are angularly offset to the perpendicular as shown in the drawings and as necessarily required where the foot 3 of the bracket 6 is corrugated along with the rest of the bracket in order to increase its overall stiffness.

As will be appreciated, although the living control hinges 9 are disposed in the embodiment described immediately adjacent the oppositely disposed channels 12 they may instead be disposed elsewhere on the tongue 8, or additional such hinges may be provided so as to collectively control axial alignment of the fasteners 4 whilst they are being driven into the primary support structure. Other forms of control may be adopted such as e.g. the use of frangible webs which initially support the upper end of the fasteners in their correct alignment relative to the foot portion 7 of the foot cover 6 but which may break after the fasteners 4 have been driven in by an amount sufficient to ensure their continued, correct, progress into the primary roof structure into which they are being driven, thereby preventing the tongue portion 8 from riding up the screw threaded portion of the fasteners 4 before such screw threads reach and can engage with the foot portion 7 of the foot cover 6 and the underlying primary support structure.

Claims

Claims 1. A combination fastener alignment and insulating foot cover for

the foot of a roof/wall bar support bracket, the roof/wall bar being of the type in which a grid of such bars are supported by a plurality of such brackets on a primary support structure, and onto which grid can thereafter be fixed a roof/wall membrane, the foot cover comprising a lower, insulating, sole portion adapted to be disposed, in use, between the foot of the roof/wall bar support bracket and the primary support structure on which the bracket is to be fixed, and an upper fastener alignment tongue portion spaced from but connected to said sole portion by hinge means and including fastener receiving and fastener alignment apertures for receiving fasteners therein in a required alignment orientation prior to being driveninto said primary support structure.
2. A combination fastener alignment and insulating foot cover according to claim I further characterised in being integrally moulded from plastics and including at least a pair of fastener receiving and alignment apertures, adjacent to each of which is a living control hinge allowing the tongue portion to collapse in a controlled manner onto the top of the foot of the bracket when the fasteners are driven into the primary support structure.
3. A combination foot cover according to claim 2 further characterised in that on that portion of the tongue portion remote from the living control hinge and fastener receiving apertures there are ribs depending therefrom such that as the tongue collapses onto the top of the foot of the bracket when a respective fastener is driven into the primary support structure its respective rib compensates for any distortion which may otherwise be caused by the compressed material around the living hinge.
4. A combination foot cover according to any preceding claim further characterised in that the upper surface of the sole portion is shaped to follow the profile of the lower surface of the foot of a roof/wall bar support bracket.
5. A combination foot cover according to claim 4 further characterised in that the lower surface of the sole portion is substantially planar.
6. A combination foot cover according to any preceding claim further characterised in including bracket edge receiving formations allowing the cover to be slideably receivable on the foot portion of a respective bracket.
7. The combination of a roof/wall bar support bracket, onto the foot of which is secured a fastener alignment and insulating foot cover which includes fasteners, such as a pair of screw-threaded fasteners, driven therein but not therethrough such that upon placement of the bracket within or on a roof/wall bar and being positioned onto a primary support structure no separate step is required on site to ensure correct alignment of the fasteners relative to the foot of the bracket
8. A combination support bracket according to claim 7 further characterised in that the fasteners are screw threaded fasteners.
9. A combination fastener alignment and insulating foot cover substantially as described with reference to the drawings.
10. A combination fastener alignment and insulating foot cover and associated fasteners driven therein but not therethrough substantially as described with reference to Figures 1 and 2.