AU726947B3 - Mesh screen with improved system for fastening to rainwater guttering - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION PETTY PATENT for the invention entitled: "MESH SCREEN WITH IMPROVED SYSTEM FOR FASTENING TO RAINWATER GUTTERING" The following statement is a full description of this invention, including the best method of performing it known to me: MESH SCREEN WITH IMPROVED SYSTEM FOR FASTENING TO RAINWATER GUTTERING Background and Summary of the Invention This invention concerns the use of mesh, particularly mesh made from plastics materials, to cover the guttering along the edge of the roof of a house for the purpose of preventing the entry of unwanted materials such as sticks, leaves and other tree debris, large insects, litter and the like into the guttering.

The use of various mesh materials to cover roof guttering to prevent the ingress of leaves and sticks is well known. Typically the aperture size of the mesh used is in the range from about 1.5mm to about 2mm. At the large end of this range the holes in the mesh are proned to catch leaves and sticks and the debris so caught results in a significant barrier to the removal of further leaves and sticks from the roof. With meshes having the smaller aperture sizes, leaves and sticks are not so readily caught but water running from the roof has a much greater tendency for "sheeting" or running over the top of the mesh rather than falling through the apertures into the guttering.

One particularly successful method of covering guttering with mesh involves taking a strip of mesh of width from 25cm to 100cm and running the full length of the guttering and affixing one longitudinal edge of this strip to the roof material and the opposite edge of the mesh strip to the upper edge of the guttering. Along the edge of the mesh strip affixed to the top of the guttering, it is common to provide a strip of angle sectioned metal to hold the mesh to the guttering. Screws are fixed through the metal angle to clamp the mesh between the angle and the guttering to help prevent the mesh from pulling away.

However there is still a significant tendency for the mesh to tear and pull away if a load is placed upon it. Such a load could be by someone on the roof accidentally stepping on the mesh, or possums, cats and the like runnfiing along the roof edge. A particular problem occurs due to the relatively large thermal expansion of plastic mesh whereby up to I or 2mm expansion and contraction can occur. When a mesh screen is neatly tensioned in hot weather, later cold ambient temperatures can lead to failure of the mesh at the locating screws. A fine weave on the edge of the mesh has been tried but this has given only a small degree of improvement in the tendency of the mesh to pull away under load.

An aim of the present invention is to provide a mesh and installation method which substantially reduces these difficulties.

Accordingly, in one aspect the invention provides a screen for fixing to the top of roof guttering to prevent sticks and leaves entering the guttering, said screen comprising a long strip of mesh, said strip having two lengthwise edges with a first of the lengthwise edges having a plurality of generally parallel ribs, each rib extending from the plane of the mesh and running lengthwise along or adjacent said first lengthwise edge, said ribs being spaced apart from each other sufficiently for a fixing element having a head to be pushed between the ribs so that the head of the fixing element or a collar beneath the head may bear upon the parallel ribs to spread the load on the mesh.

When affixed to the top of a roof guttering, the screen may comprise the long strip of mesh fixed along said first lengthwise edge to the top outer edge of the guttering and fixed along the second lengthwise edge of the strip to the roof, the strip having said generally parallel ribs extending from the plane of the mesh downwards towards the top outer edge of the guttering, and screws passing through said strip near the first edge through said spacing between adjacent ribs and threadedly engaging with the upper outer edge of the guttering In another aspect the invention provides a screen applied to the top of a roof guttering to prevent sticks and leaves entering the guttering, said screen comprising a long strip of mesh fixed along one of its lengthwise edges to the roof and along the opposite Xq lengthwise edge of the mesh to the top outer edge of the guttering, the mesh having a plurality of generally parallel ribs extending along or adjacent the edge of the mesh and extending from the plane of the mesh downwards towards the top outer edge of the guttering and screws passing through said outer edge of the mesh and between adjacent ribs and threadedly engaging with the upper outer edge of the guttering.

In a further aspect the invention provides a method of preventing the entry of sticks and leaves into a guttering on a roof of a building including affixing a screen over the edge of the roof and the guttering, said screen having a strip of mesh configured and affixed as described above.

Brief Description of the Drawings In order that the invention may be more fully understood there will now be described, by way of example only, preferred embodiments and other elements of the invention with reference to the accompanying drawings where: Figure 1 shows diagrammatically an installation of a guttering screen according to the prior art; Figure 2 is a cross-section view through guttering having a screen according to one embodiment of the present invention; Figure 3 is a plan view of a portion of one form of mesh which can be used in the arrangement shown in Figure 2; Figure 4 is a plan view of a portion of an alternative mesh which can be used in the arrangement shown in Figure 2; Figure 5 is an end-on view looking lengthways along portion of a further mesh used in an alternative embodiment of the invention; and Figure 6 is a view similar to Figure 2 except that a mesh generally as shown in Figure 5 is used for the screen.

Detailed Description of Embodiments Referring to Figure 1, the corrugated steel roof 10 has a fascia 12, soffit 14 and guttering 16 to collect the rainwater from the roof. A screen 18 to keep leaves and sticks out of the guttering is formed by unrolling a strip of mesh along the length of the guttering and attaching the long inner (roof-side) edge 19 of the mesh to the roof with appropriate cleats or clips 20 screwed onto the roof metal through the mesh. The outer long edge 22 of the mesh is attached to the curled lip which forms the top outer edge 24 of the guttering by way of angle trim 26 which is screwed at appropriate intervals to the curled lip 24 of the guttering. The lip 24 forms the top edge of the gutterings outer face 25. In a situation (not shown in the Figures) where the roof has roofing tiles, the screen may be attached to the roof by the weight of the second bottom row of tiles being laid upon the mesh.

It has been found from experience that conventional meshes used for such screening applications require the use of the angle trim 26 in order to more securely affix the mesh to the guttering. Without the angle trim the mesh is easily damaged where the screws penetrate it whenever the screen is subjected to a significant load such as a possum or cat walking along the mesh, someone on the roof inadvertently stepping on the screen or large temperature differentials giving high levels of thermal contraction.

In addition, it has been found that the mesh is still prone to stretching and damage under these conditions even when the angle trim is used.

Referring to Figure 2, a screen 38 according to one embodiment of the invention is shown attached to guttering 36. A mesh generally the same as that of Figure 2 is shown in plan view in Figure 3. The mesh in the screen is formed from a plastics material (preferably UV stabilised polyethylene) and has strands which are in the range of 0.8 to 1.7mm, preferably about 1.0mm, diameter and spaced at centres in the range 4mm to 9mm, preferably about 7mm, to give an aperture size in the range 2.0 to preferably about 3.0mm. The inner edge of the screen 38 (not shown in Figure 2) is attached to the roof of the house by one of the conventional ways described above. However the outer edge 42 of the screen carries one rib lengthwise along the edge of the mesh and another rib 41 inboard of the edge rib The ribs each have a cross-section of about 8mm wide and 4mm high. They are firmly bonded to one face of the mesh either by being welded or glued to the mesh or, more preferably, formed integrally with and as part of the process of moulding the mesh.

The two ribs 40 and 41 are spaced apart just sufficiently for the fixing screws 48 to be pushed between the ribs and through the mesh. In practice this spacing is in the order of 4mm. The fastening screws 48 have a pancake head or, more preferably, a wide collar formed just beneath the head in order to spread the load on the mesh. With mesh formed and fastened in this manner there is a greatly reduced tendency for the mesh to stretch or tear away from the screws when a vertical load or strong thermal contraction is applied to the mesh. The angle trim reinforcement 26 as shown in Figure 1 is no longer required.

It has also been found that such an arrangement of a plurality of ribs provides superior performance to that of a single rib. The reason for this is that with a single rib of the relevant size, holes for the screws need to be pre-drilled or in some other way preformed into the rib because otherwise the rib has a tendency to split in use. Predrilling is an additional step in the installation process and it is more economical to avoid. Alternatively, if the screw holes are moulded into the rib during its forming process, this adds additional cost to the manufacture and also can lead to the holes being in an unsuitable position when the screen is being installed on site.

Preferably ribs are formed integrally with the mesh, the whole strip of mesh being moulded integrally with the ribs from UV stabilised polyethylene in a single continuous operation.

Whereas the mesh in Figure 3 has its strands 50 and 51 oriented in rows respectively parallel and at right angles to the longitudinal, edges of the mesh, and thus also to the ribs, the alternative mesh shown in Figure 4 has its strands 54 and 55 aligned at 45' to the lengthwise (longitudinal) edges and ribs. Also for the mesh in Figure 4, the diameter of its strands and the size of its apertures are somewhat larger than those described above with reference to Figure 3. Other diamond shaped or rectangular shaped apertures for example may alternatively be chosen as desired. The orientation and size of the holes in the mesh through which the water passes may be chosen to suit aesthetics or particular water flow properties required.

The screen 38 is installed over the guttering 36 with the ribs 40 and 41 preferably protruding downward from the mesh so that they come in direct contact with the top outer edge 44 of the guttering. If the ribs are directed upwards to engage the underside of the screw head or washer, they will undesirably provide a potential additional barrier to sticks and leaves sliding off the top face of the screen.

Figure 5 shows an end view of portion of an alternative mesh 58 suitable for installation as a screen according to the present invention. The longitudinal edge 59 used for the outer edge of the screen has four ribs 60 to 63 protruding from the plane of the mesh and the method of fixing these is illustrated by Figure 6. Each of these ribs has width x height dimensions in the range of 1.0 x 3.0mm to 2.5 x 6.0mm and preferably about 2mm wide and 5mm high.

In each of the embodiments the ribs along and adjacent the edge of the mesh provide a substantial means of reinforcement against tearing and stretching and also make the edge much more rigid, so reducing the catenary effect between adjacent screws. The four-rib version shown in Figures 5 and 6 is particularly advantageous because a backup rib 60 is available if the first rib 61 under tension fails.

An advantage of the embodiment shown in Figure 6 is that slight variations in the width of the guttering can be easily accommodated by moving the screw from between the central ribs 61 and 62 as shown in Figure 6 to between either of the other adjacent pairs. This provides an additional means of adjusting the fit during the fixing process.

Another significant advantage of the embodiment as shown in Figure 6 is that the inner rib 63 provides a good drip point to encourage water flowing along the mesh to fall into the guttering earlier than it would otherwise have done so.

The meshes shown in Figures 5 and 6 are slightly different. In the mesh of Figure 6, the longitudinal and lateral strands 69 and 70 respectively of the mesh are in substantially the same plane whereas in Figure 5 the mesh is moulded such that the longitudinal strands 66 lie in one plane while the lateral strands 67 lie in an adjacent plane. In Figure 5 the ribs 60 to 63 run along the opposite side of the lateral strands 67 to the side where the longitudinal strands 66 are.

Whilst the above description includes the preferred embodiments of the invention, it is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention.

It will be also understood that where the word "comprise", and variations such as "comprises" and "comprising", are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of other feature or features.

Claims (3)

1. A screen for fixing to the top of roof guttering to prevent sticks and leaves entering the guttering, said screen comprising a long strip of mesh, said strip having two lengthwise edges with a first of the lengthwise edges having a plurality of generally parallel ribs, each rib extending from the plane of the mesh and running lengthwise along or adjacent said first lengthwise edge, said ribs being spaced apart from each other sufficiently for a fixing element having a head to be pushed between the ribs so that the head of the fixing element or a collar beneath the head may bear upon the parallel ribs to spread the load on the mesh.

2. A screen according to claim 1 wherein the mesh is formed of a plastics material, the ribs are integrally formed with the mesh and the ribs are spaced apart by a distance of the order of 4mm.

3. A screen according to either claim 1 or claim 2 when affixed to the top of a roof guttering, said screen comprising said long strip of mesh fixed along said first lengthwise edge to the top outer edge of the guttering and fixed along the second lengthwise edge of the strip to the roof, the strip having said generally parallel ribs extending from the plane of the mesh downwards towards the top outer edge of the guttering, and screws passing through said strip near the first edge through said spacing between adjacent ribs and threadedly engaging with the upper outer edge of the guttering. Dated this 15 th day of March 2000 Bruce Percival Wickett by his patent attorney Norman Morcom