AU2007100177B4 - Leafguard - Google Patents

Description

Editorial Note Description Starts at Page 2. Abstract is Page numbered 1.

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Field of Invention

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This invention relates to gutter guards, as a means for preventing the entry of leaves, debris and vermin into the open gutter, which may cause blockages to the gutter system.

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o Background of the Invention Most buildings incorporate a gutter system in their design to assist in the diversion of

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o 15 rainwater from the roof surface. Essentially this prevents flooding and undermining of the foundations and also provides a means for channeling rainwater to a catchment facility.

As rainwater is becoming an increasingly valuable resource the harvesting and re-use of rainwater from the roofs of buildings is desirable both for its environmental and economical benefits.

Australia's well publicized bushfire threat in populated regions is another area of major concern. Airborne embers from bushfires may ignite 'dry-leaf build up' in guttering, thereby creating a significant fire hazard.

In the past the use of many forms of woven and extruded plastic mesh inserted into the gutter has been a popular choice due to its low cost and ease of installation, however these plastic products have proven inadequate in most instances especially where a fire resistant product is required to meet council regulations. Also, due to the way some mesh is rolled concave convex to fit into the gutter it tends to act as a barrier accumulating leaf and debris. The unnecessarily large hole sizes used in many of these meshes also tend to entrap the leaf stem and twigs creating both an unacceptable appearance and potential fire hazard.

In recent times several perforated, expanded and woven metal products have appeared on the market, however many of these have retained inadequacies of the plastic mesh (i.e.

unnecessarily large hole sizes). As previously stated leaves and twigs are easily entrapped in large mesh openings, encouraging the build-up of leaf mulch. If left unattended this leaf mulch may promote premature breakdown of the metal mesh and guttering and reduce the overall effectiveness of the system.

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Whilst metal mesh may prove significantly more fire resistant than plastic it is however subject to atmospheric degradation, especially in coastal locations. Protective coatings such as painting and powder coating are generally employed to combat this problem, but 0 due to some manufacturing processes many of these metal meshes are perforated and expanded after being coated and some woven mesh is coated after weaving, thereby rendering some areas of the mesh unprotected. This inability to treat the total surface area

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O of the mesh may lead to rust and corrosion problems, once again reducing mesh performance and life expectancy, and possibly creating an adverse reaction with the roof

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o 15 surface.

The size of the openings and shape of the mesh dramatically effect the way the system performs. Flattened smooth metal mesh whether perforated or expanded provides minimal resistance as water flows across it, therefore relatively large openings are required to break this water flow and direct water through the mesh. Also as wet leaves dry they have a tendency to stick to flat surfaces creating a 'snag' for other debris.

Louvered (cheese grater style) mesh is designed to be positioned so that when viewed from a point on the roof looking towards the gutterline, no holes are visible and when looking in the opposite direction from a point beyond the gutterline the holes appear relatively large and open. Whilst in theory this louvered design prevents debris entering the gutters the effect is predominantly achieved during heavy rainfall as the excessive flow of rainwater washes debris down the pitch of the roof and across the louvered surface. As a compromise these louvered openings are again required to be of a relatively large size to allow the fast flowing water opportunity to enter the gutters and not pass across the mesh to the gutters outer-edge. Observation indicates that the majority of small debris slowly migrates down the pitch of the roof surface due to a number of factors; Gravity, dew, rain showers, and light breezes. This gradual migration allows small debris to enter these large openings whilst wind activity may also cause debris to be blown back into the louvered openings eventuating in sediment buildup in the gutters, an undesirable outcome.

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o Mesh has been cut, shaped, and fixed in many forms to correspond to the roof surface it

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attaches to, however most prior art examples have not worked very affectively. Some systems use saddles/clamps which tend to catch leaves and twigs and look unattractive, whilst other systems use double sided tape which does not generally perform long term.

In regards to metal roof profiles e.g. Custom orb (corrugated) some prior art shows a variety of scalloped shapes which form into the corrugated profile, however in general these scallops are too short in length and instead of forming a gradually sloping O transition from roof surface to mesh top tends instead to create an abrupt dam like effect which catches debris and appears unsightly.

0 O When fitting gutter mesh to a tiled roof some systems are fixed to the outer gutter edge, across the first row of tiles and fixed under the second row of tiles. In most cases this system works quite effectively however, the appearance is unacceptable to many property owners. Other systems that fit inside the gutter generally fail as they tend to sit higher than the gutter tile bottom edge and create a barrier, conversely the mesh fits too low in the gutter sometimes sloping in the wrong direction (back towards the fascia) also the leading edge of the mesh maybe fitted into the roll of the gutter lip thereby creating a barrier, again accumulating debris. Other prior art shows mesh that fits under the first row of tiles between the fascia board and tile, this mesh has 90 degree folds along the length of the mesh. The mesh fits below the trough of the tile perpendicularly against the front edge or nose of the tile, unfortunately the mesh makes contact with the foremost protruding point of the tile edge so that any irregularities or (dags) on the tile edge prevents the mesh from obtaining a very close fit thereby creating a gap in which leaves are trapped.

This present invention seeks to alleviate at least one of the problems associated with prior art and provide a substantial contribution to the working of such prior art.

Summary O 0 The Invention In a first broad form the present invention provides a mesh filter tbr preventing the ingress of leaf and debris into a gutter or the like.

The gutter mesh filter comprises a semi-rigid length of expanded metal sheet (preferably aluminium) having typically uniliorm hexagonal shaped openings /apertures and substantially large elongated protruding joints which produce a predominantly recessed surtace.

These protruding joints are designed to run across the width of the sheet providing extra strength and durability (when compared to prior art expanded mesh) this significantly reduces the possibility of snapping and breaking where acute angled ol6diing along the length of the mesh is required.

The recessed surface arrangement of this invention breaks the surface tension as the rainwater flows across it reducing the likelihood of*sheeting allowing mesh \ith opening of relatively small dimension (when compared to prior art expanded mesh) to perform effectively in diverting the flow of rainwater into these openings.

*Sheeting is a phenomenon which occurs as liquid (water) passes at a particular flow rate over a substantially flat surface comprising apertures which are of a dimension (size &/or shape) that thil to direct the flow of water into these openings This recessed surtace combined with the relatively small hexagonal shaped openings thereby substantially reduce the likelihood of fine debris entering through the mesh into the gutter when compared to louvered or flattened mesh with relatively large openings.

Another significant advantage of the recessed surface of this invention as opposed to a flattened/smooth surface is the enhanced leaf shedding capabilities. The leaf is suspended on the elongated protruding joints making contact with only the high points of the recessed surface. This greatly assists natural wind action to flow more effectively under the leaf increasing the probability of the leaf being blown offtthe mesh to the ground This high point suspension of the leaf also alleviates another problem whereby wet leaves as they dry tend to stick to flat/smooth surfaces due to their contact with the larger surface area. These leaves may create snags promoting the accumulation of further debris on the mesh.

r 5 flat/smooth surfaces due to their contact with the larger surface area. These leaves may 0 0 create snags promoting the accumulation of further debris on the mesh.

This present invention is designed to correspond with the roof material used providing a neat, close fitting junction between the mesh and the roof.

0 The edge of the mesh is cut/shaped and folded prior to the powder coating process so that no cut edges are exposed, ensuring total coating protection.

Metal Roof O When used in relation to custom orb corrugated metal roofing the edge of the mesh is cut in a scalloped wave like profile. These scallops which are significantly longer and 0 O 15 more elongated than prior art are folded to correspond with the pitch angle of the roof.

This produces a more gradual slope from the roof surface to the mesh top surface significantly reducing the abrupt angle and damlike effect created by some prior art.

The mesh is fixed (screwed riveted) through the mesh to the high point of the corrugated roof profile eliminating the need for clamps saddles to hold or form the mesh to the roof surface. The outer gutter edge of the mesh is fitted to the top edge of the gutter lip roll using screws or rivets or 90 degree angle cover trims. It is also possible to simply fit the mesh into the roll of the gutter which appears quite neat however a 10 m barrier is formed by the lip which may cause debris to accumulate, therefore this method is not recommended.

Tiled Roof When used on a tiled roof the present invention is designed in a unique shape which is created by folding along the length of the mesh acute angles of approximately degree and also a third less acute fold which provides a pivot point This pivot point #3 creates an extra strengthening fold increasing the rigidity of the mesh and also reduces the possibility of leaves laying flat on the mesh, this aids wind action to more effectively dislodge leave from the mesh. The shaped folds #1 #2 allow for modem round nosed tiles and tiles with uneven 'dagged' edges to make closer contact with the mesh when compared to prior art, Only the #1 point of the shape makes contact with the r> 5 tile edge reducing the likelihood of a gap in which debris may be trapped. This effect can

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o be more easily realised in the following diagrams Ct By compressing the shape the distance between the two points #1 #2 of the is adjusted to suit the thickness of the tile.

0 To fit the present invention to a tiled roof the mesh is firstly fixed to the gutter edge in the same manner as with a metal roof.

O To fit the roof side of the mesh the first row of tiles are slipped back up the roof, t exposing the top edge of the fascia board. A screw is fixed through the mesh into the top

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o 15 of the fascia at appropriate intervals to hold the mesh in place. The tiles are then slipped back down making sure that the nose of the tiles fits snuggly against the #1 point of the on the mesh. If required a bead of silicone sealer may be applied to this joint.

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T n i Brief Description of the drawings The present invention will become more fully understood on viewing the following detailed description of a preferred but non-limiting embodiment thereof, described in O connection with the accompanying drawing, wherein, Fig.1 Depicts a side cross-sectional view of a first embodiment of the present invention

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o 15 installed across a gutter wherein an engagement portion is fitted to a corrugated profile 'metal roof' Fig.2 Depicts a side cross-sectional view of a first embodiment of the present invention installed across a gutter wherein an engagement portion is fitted to a 'tiled roof'.

Fig.3 Depicts an enlarged top-view perspective of a section of the present invention detailing the 'hexagonal' shaped openings Aand the large elongated 'Joining Knuckles'

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Fig. 4 Depicts and end view perspective of a section of the present invention detailing the elongated 'joining knuckles' B and 'dimpled surface' C Fig. 5 Depicts an actual size top view perspective of a section of the present invention detailing the elongated 'scalloped' contour edge D which corresponds to the 'custom orb/corrugated' profile metal roof sheeting E Fig.6 Depicts a side cross-sectioned view of the folded mesh when used on a tiled roof detailing the acute angle folds #1 and #2 which create a Z shaped fold allowing only the point of the #1 fold to make contact with the nose (front edge) of the tile.

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c'1 Fig.7 Depicts a side cross-sectional view of the folded mesh when used on a 'modern curve nosed' tiled roof detailing the close contact achieved by the Z shape profile of the mesh.

0 O Fig.8 Depicts a side cross-sectional view of the folded mesh detailing a 3 d fold which provides a pivot point This pivot point #3 allows wind action to flow more easily O 15 under the leaf causing leaves to be dislodged from the mesh.

This fold #3 also provides extra strength and rigidity to the mesh

Claims (4)

1. A guard for excluding debris from a rain gutter of the type mounted to a building roof, said guard including an expanded metal sheet to fit between the roof and an outer edge of said gutter wherein said sheet is formed with a plurality ofhexagonally shaped apertures for passing rainwater flow therethrough and elongated protruding joints between said apertures which are shaped to form a recessed surface of said sheet to break up said rainwater flow and to direct said flow into the apertures and said elongated protruding joints being orientated in a direction which in use of said guard extends across a width of said sheet between the roof and said outer edge of the gutter whereby the possibility of sheet breakage at any longitudinal folds along the length of said gutter is reduced.

2. The guard as claimed in claim I wherein said sheet is formed from aluminium which has been anti corrosion chromate pre-treated and powder coated.

3. The guard as claimed in claim I wherein said sheet includes an edge profile which is contoured to closely engage a surface of said roof. -11-

4. The guard as claimed in claim 3 wherein said edge profile is a scalloped wave-like profile which is bent to closely engage and correspond to the pitch of a corrugated metal roof. The guard as claimed in claim I wherein said sheet is formed into a Z shape to facilitate close engagement with round nosed tiles or other roof tiles with uneven edges Dated this 15th day of June, 2007 Grahame Roy Webber By His Patent Attorney MICHAEL ANDERSON-TAYLOR