AU755848B2 - Roofing sheet retaining clip - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: STRATCO (AUSTRALIA) PTY LIMITED Actual Inventor: Michael Roy Stenhouse Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention title: ROOFING SHEET RETAINING CLIP Details of Associated Provisional Application No: PP 7755 dated 16 December 1998 The following statement is a full description of this invention, including the best method of performing it known to us.

The present invention relates to the retention of roofing sheets to roof structures such as purlins and in particular relates to roof sheet retaining clips that obviate the need for penetrations through roofing sheets.

Various arrangements of methods and means for retaining steel roofing sheets to purlins are known.

One method is to use nails or screw fasteners to attach the roofing sheets to the purlins below. The acceptability of this method relies on the ability to obtain a seal between the fastener and the hole in the roof sheeting through which the fastener passes. The seal must be sufficient to prevent the ingress of water into the roof space S below the fixed sheets.

0% e A second method of attaching ribbed roofing sheets to purlins is the use of clips of various kinds which interact with the ribs from below the sheet to retain the sheet to the purlins. Clips that are located between the purlins and the underside of the roofing sheeting have the advantage that they are concealed and do not require penetrations through the roofing sheets. However, existing designs for concealed fixing clips are complex, expensive to produce and not always easy to install.

It is therefore an object of the invention to provide an improved roofing sheet retaining clip that overcomes at least some of the abovementioned problems.

SUMMARY OF THE INVENTION According to the invention, there is provided a roofing sheet retaining clip comprising a one-piece elongate strip having: an upstand end which has an underside profile adapted to fit over the upper side of a roofing sheet rib and an upper side profile adapted to receive the underside of a roofing sheet rib; at least two intermediate upstands each adapted to receive and retain the underside of a roofing sheet rib; and a tab end having a slot of greater length than width extending longitudinally of said strip wherein the pitch between said upstands is constant and the distance between the centre of the intermediate upstand nearest said tab end and the far end of said slot is greater than said pitch and the distance between the centre of the intermediate upstand and the near end of said slot is less that said pitch.

Having the tab end extending a distance greater than said pitch enables the first upstand end of a second roofing sheet retaining clip to be joined to the second tab end of a first roofing sheet retaining clip with overlap, while retaining a constant pitch between upstands for the assembled pair of clips.

Preferably said roofing sheet retaining clip is further characterised in that said intermediate upstands are shaped as an inverted and have lateral projections adapted to retain said roofing sheet ribs.

S 15 Preferably said roofing sheet retaining clip is further characterised in that between each of said upstands said elongate strip has at least one fold about an axis parallel to its longitudinal axis, to thereby strengthen said strip.

ooo.oi A specific embodiment of the invention will now be described in some further detail 20 with reference to and as illustrated in the accompanying figures. This embodiment is illustrative, and is not meant to be restrictive of the scope of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION The embodiment is illustrated in the accompanying Figures in which: Figure 1 shows a perspective view of a roofing sheet retaining clip according to the invention; Figure 2 shows the clip of Figure 1 in an underside perspective view; Figure 3 shows a side view of the clip of Figure 1; Figure 4 shows two clips according to the invention positioned for assembly end to end of one another (purlins or roof sheets not shown); and Figure 5 shows respective ends of two roofing sheet retaining clips according to the invention over each other just prior to their fastening together. This figure also shows how the ends of adjacent roofing sheets are retained using the roofing sheet retaining clips Figure 1 shows a roofing sheet retaining clip 10 comprising a one piece elongate strip. The elongate strip has an integral first upstand end 11 with an underside profile adapted to fit over the top of a roofing sheet rib and a top side profile adapted to receive the underside of a roofing sheet rib; two integral intermediate upstands 12 and 13 are each adapted to receive and retain the underside of a roofing sheet rib; and an integral tab end 0 Tab end 15 has a slot 26 extending longitudinally of the roof sheet retaining clip The pitch (the linear distance as depicted pictorially in Figure. 1) between the centre lines of the upstands 11, 12 and 13 is constant and the distance between the centre of ooeee S the intermediate upstand 13 (nearest the tab end 15) and far end of the slot is greater 20 than this pitch and the distance between the centre of the intermediate upstand and the near end of the slot is less than this pitch.

Referring to Figure 3 the intermediate upstands 12 and 13 are shaped like an inverted and have lateral projections 20. The function of these lateral projections 20 is to provide a positive connection to the re-entrant portions of the ribs of the roofing sheeting. Each side of the upstands 12 and 13 of the elongate strip has recesses 21 which provide a depression for the head of fasteners used to connect the roofing sheet retaining clip to purlins below so that it does not directly contact the underside of the installed roofing sheet. A plurality of holes 25, shown in Figure 2 provide apertures through which fixing means can be used to attach the roofing sheet retaining clip 10 to roof purlin. Attachment slot 26 is provided within tab 15 which itself is recessed from the top 16 of the elongate strip. Also at the tab end 15 of the clip 10, as depicted in Figure 2 is a tab 24 in which hole 25 is located. The tab 24 is also recessed from the top 16 of the elongate strip.

The use of roofing sheet retaining clips 10 will now be described. After constructing a roofing structure to purlin level, a set of roofing sheet retaining clips 10 are laid onto the purlin with the tab ends 15 directed along the purlin in the roofing sheet laying direction down the width of one side of the roof. Clips are aligned so that their upstands lie on parallel lines with respect to adjacent purlins so that a first sheet can be laid down over the clips. Once positioned, the roofing sheet retaining clips are fastened to their respective purlins using at least three self tapping screws or other suitable fasteners through holes 25. The first roofing sheet can now be placed over the clips. Each rib of the roofing sheet is then snapped onto each purlin using foot pressure ensuring complete roofing sheet engagement for every rib on every roofing sheet retaining clip 10. The next row of roofing sheet retaining clips 10 can now be positioned on the purlins with their upstand ends 11 hooking over the last S rib of the previously laid roofing sheet and their tab end directed along the purlin in the roof sheet laying direction. The end attachment hole 25' is located somewhere over the slot 26 of the previously laid retaining clip 10. With the hole 25' and slot 26 oo.oop aligned, a fastener is inserted to retain the newly laid retaining clip 10' and simultaneously fasten it to the previously located retaining clip 10. This arrangement .is shown in Figure The attachment slot 26 allows for some variability of the lateral position of the next clip as the sheets may vary very slightly in width and the last rib of the sheet may need to be slightly compressed or stretched laterally to ensure that respective upstands of the clips along the length of each sheet remain parallel and at approximately constant pitch and to compensate for any variation in the squareness of the roof structure.

To complete the retention of the newly laid retaining clip 10' at least two additional fasteners are inserted through attached holes 25 to the purlin below before the second roof sheet is laid. The second roofing sheet can now be placed over the retaining clips ensuring that the ends of the roofing sheet are aligned with the first sheet. The inner face between successive roofing sheets and successive roofing sheets retaining clips are shown in Figure Roofing sheet retaining clips 10 eliminate the need to pierce the roofing sheet to fix the sheet roofing to the purlins. This provides better security against entry, minimises the possibility of faster corrosion and resists updrafts which may otherwise dislodge the sheeting. Another important benefit is that water tightness of the roof does not rely on the performance of washers and is less dependent on installer competence. Due to the combination of rib height and concealed clips, roofing sheets can be installed on roofs with pitches as low as 1 degree. This reduces the need for extensive parapet structures to conceal the roof, reducing flashing cost and makes for a safer roof traffic during maintenance and installation.

While the present invention has been described in terms of a preferred embodiment in order to facilitate better understanding of the invention, it should be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope.

.6 S0•0

Claims (3)

1. A roofing sheet retaining clip comprising: a one-piece elongate strip of metal having an upstand end which has an underside profile adapted to fit over the upper side of a roofing sheet rib and an upper side profile adapted to receive the underside of a roofing sheet rib; at least two intermediate upstands each adapted to receive and retain the underside of a roofing sheet rib; and a tab end having a slot of greater length than width extending longitudinally S•of said strip wherein the pitch between said upstands is constant and the distance 5 between the centre of the intermediate upstand nearest said tab end and the far end •@oo of said slot is greater than said pitch and the distance between the centre of the intermediate upstand and the near end of said slot is less that said pitch.

2. A roofing sheet retaining clip according to claim 1 wherein said roofing sheet retaining clip intermediate upstands are an inverted shape and have lateral I *projections adapted to retain said roofing sheet ribs. ooooo 20

3. A roofing sheet retaining clip according to claim 1 wherein said elongated .4•o strip has between each of said upstands at least one fold about an axis parallel to its longitudinal axis to strengthen said strip. Dated this 10h day of December, 1999. STRATCO (AUSTRALIA) PTY LIMITED By its Patent Attorneys MADDERNS