AU2009201759A1 - A grate or cover - Google Patents

Description

S&F Ref: 905479 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Patrick Pussell, of Applicant: of C201/27 Cadigal Avenue, Pyrmont, New South Wales, 2009, Australia Actual Inventor(s): Patrick Pussell Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: A grate or cover Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2008902758 02 Jun 2008 The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(2088158_1) I A GRATE OR COVER Field of the Invention The present invention relates to grates and covers of the type commonly used to 5 cover pits, sumps and other openings in roads and other surfaces. Grates support vehicular and pedestrian traffic passing over an opening and usually include a partially open mesh or grid surface to allow water to drain therethrough. Covers have a similar construction to grates, but with a solid top, and are often used to close access points. Covers can also include openings in their top or sides to act to as vents for pressure, fluid or gas, to escape from below the cover. Background of the Invention There are two main types of existing grates, cast iron and steel. Cast iron grates are typically sand-cast as a unitary structure and include a number of parallel bars 15 extending across the width of the grate. Steel grates are typically formed from a number of discrete mild steel bars that are welded together. In cross-section, the bars of cast iron grates taper inwardly from top to bottom whilst the bars of steel grates are rectangular. The strength of a grate is predominantly determined by the depth and width of the bars. The increase in strength due to increase in bar width and bar depth is linear and 20 logarithmic respectively. As grates must have adequate openings between the bars for flow of water and other materials, increasing the strength of mild steel grates is generally restricted to only increasing the depth of the bars. However, for cast iron grates, it is possible to produce bars of non-constant cross-section which are deepest at their mid point in order to increase load carrying capacity. This also allows the bars of a cast iron 25 grate to have edges that can be kept within normal edge mounting dimensions, whilst the bars of mild steel grates eventually become too deep for fitment when of sufficient strength for high load applications. Increasing strength by adding extra bars is possible, but it reduces the spaces between the bars and thus has a detrimental affect on the flow rate of water able to pass 30 through the grate. Cast iron grates can carry larger loads than equivalent section mild steel grates as they can be cast in metals of higher tensile strength, typically 500 MPa. However, due to labour intensive casting methods, they are more expensive to produce and heavier, which leads to increased transport costs. As a result, mild steel grates have become increasingly 2 popular over the last ten years due to the lower initial cost. However, many mild steel grates have begun to fail after 5-10 years of service. Object of the Invention 5 It is the object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages of the prior art grates and covers. Summary of the Invention Accordingly, the present invention provides a grate or cover including: 10 a peripheral frame; a surface part laterally within the peripheral frame; a reinforcing part positioned laterally inwardly from the peripheral frame and having at least one wall depending from the surface part with an inwardly facing lip on its distal edge; and is at least one strut connecting the reinforcing part to the peripheral frame. The walls preferably form a hollow structure extending from the surface part to the lip or lips. The lip or lips preferably extend around the entire distal edge of the hollow structure. The wall(s) and lip(s) preferably together form an L-shape in cross-section. The at least one wall preferably also includes an outwardly facing lip on its distal 20 edge. The wall(s) and lip(s) preferably together form an inverted T-shape in cross section. The reinforcing part preferably includes four walls arranged in a rectangular formation and has four or eight struts connecting the reinforcing part to the peripheral frame. 25 The reinforcing part preferably includes three walls arranged in a triangular formation and has three struts connecting the reinforcing part to the peripheral frame. The reinforcing part preferably includes one circular or oval wall and has four struts connecting the reinforcing part to the peripheral frame. In grate form, the surface part is preferably a partially open mesh or grid. In 30 cover form, the surface part is substantially solid. The strut(s) preferably also connect the reinforcing part to the surface part.

3 Brief Description of the Drawings Preferred embodiments of the present invention will now be described, by way of examples only, with reference to Fig. 1 is an upper perspective view of a first embodiment of a grate; s Fig. 2 is a lower perspective view of the grate shown in Fig. 1; Fig. 2 is a top view of a second embodiment of a grate; Fig. 3 is a side view of the grate shown in Fig. 2; Fig. 4 is a cross-sectional side view of the grate shown in Fig. 2; Fig. 5 is an end view of the grate shown in Fig. 2; l0 Fig. 6 is a cross-sectional end view of the grate shown in Fig. 2; Fig. 7 is an upper perspective view of the grate shown in Fig. 2; Fig. 8a is a bottom view of a third embodiment of a grate; Fig. 8b is a side view of the grate shown in Fig. A; Fig. 9b is a bottom view of a fourth embodiment of a grate; 15 Fig. 9b is a side view of the grate shown in Fig. 9a; Fig. I Oa is a bottom view of a fifth embodiment of a grate; and Fig. I Ob is a cross-sectional side view of the grate shown in Fig. 1 Oa, along the line lOb-10b. 20 Detailed Description of the Preferred Embodiments Figs. Ia and lb show a first embodiment of a cast-iron grate 20. The grate 20 has a generally rectangular shape and is bounded by a rectangular peripheral frame 22. The frame 22 defines the boundary of a surface part 24 that has a number of openings 26 therein formed by intersecting parallel and spaced apart straight bars 24a and parallel and 25 spaced apart sinusoidal bars 24b. The surface part 24 also includes a central solid rectangular section 28 for provision of product, manufacturer and other data. The rectangular section 28 is also suitable for receiving the centrally applied load required by the relevant Australian Standard as it distributes the load and increases load carrying capability. 30 As best seen in Fig. Ib, the underside of the grate 20 has a reinforcing part 30 formed from four walls 32 arranged in a generally rectangular or box-like formation. The walls 32 depend from the underside of the surface part 24 and each include an inwardly facing lip 34 along their distal edges.

4 The grate 20 also includes eight struts 36 which taper inwardly from the walls 32 to the frame 22. The walls 32 and lips 34 together form a beam of L-shaped cross-section which positions a relatively large amount of metal at a relatively large distance away from the 5 surface part 24. This arrangement greatly increases the overall strength of the grate 20, without causing a corresponding increase in its weight. The grate 20 thus utilises significantly less cast-iron mass content than equivalent prior art cast-iron grates whilst still conforming with relevant load carrying standards. The grate 20 can advantageously be produced as a unitary component using a relatively inexpensive sand-casting method, io and requires only a single resin core within the interior of the reinforcing part 30. Figs. 2 to 7 show a second embodiment of grate 50 which is similar to the grate 20 previously described. Figs. 8a and 8b show a third embodiment of grate 60 having a generally circular frame 22 and surface part 24 construction with a triangular reinforcing part 30. Figs. 9a and 9b show a fourth embodiment of grate 70 having a rectangular is frame 22 and surface part 24 and a circular reinforcing part 30. In these second, third and fourth embodiments, like features to the first embodiment are indicated with like reference numerals. Figs. 10a and 10b show a fifth embodiment of grate 80 in which the walls 32 of the reinforcing part 30 include both inwardly and outwardly facing lips 34 and 34' 20 respectively, which together with the walls 32 form a cross-section having an inverted T shape. It should be noted that casting this embodiment requires multiple resin cores. Although the invention has been described with reference to specific embodiments, it will be appreciated by persons skilled in the art that the invention may be embodied in many other forms. For example, the frame, surface part and reinforcing part 25 can be of various different shapes and the walls of the reinforcing part can include openings therein. The invention is also applicable to covers of similar construction to the grates described above, but having solid tops or generally solid tops with relatively small vent openings therein.

Claims (22)

1. A grate including: a peripheral frame; 5 a surface part laterally within the peripheral frame; a reinforcing part positioned laterally inwardly from the peripheral frame and having at least one wall depending from the surface part with an inwardly facing lip on its distal edge; and at least one strut connecting the reinforcing part to the peripheral frame. 10

2. The grate as claimed in claim 1, wherein the walls form a hollow structure extending from the surface part to the lip or lips.

3. The grate as claimed in claim 2, wherein the lip or lips preferably is extend around the entire distal edge of the hollow structure.

4. The grate as claimed in claims 2 or 3, wherein the wall(s) and lip(s) together form an L-shape in cross-section. 20

5. The grate as claimed in in claim 1, 2 or 3, wherein the at least one wall also includes an outwardly facing lip on its distal edge.

6. The grate as claimed in claim 5, wherein the wall(s) and lip(s) together form an inverted T-shape in cross-section. 25

7. The grate as claimed in any one of the preceding claims, wherein the reinforcing part includes four walls arranged in a rectangular formation and has four or eight struts connecting the reinforcing part to the peripheral frame. 30

8. The grate as claimed in any one of claims I to 6, wherein the reinforcing part preferably includes three walls arranged in a triangular formation and has three struts connecting the reinforcing part to the peripheral frame. 6

9. The grate as claimed in any one of claims 1 to 6, wherein the reinforcing part preferably includes one circular or oval wall and has four struts connecting the reinforcing part to the peripheral frame. 5

10. The grate as claimed in claim 7, 8 or 9, wherein the strut(s) preferably also connect the reinforcing part to the surface part.

11. The grate as claimed in any one of the preceding claims, wherein the surface part is a partially open mesh or grid. 10

12. A cover including: a peripheral frame; a surface part laterally within the peripheral frame; a reinforcing part positioned laterally inwardly from the peripheral frame and is having at least one wall depending from the surface part with an inwardly facing lip on its distal edge; and at least one strut connecting the reinforcing part to the peripheral frame.

13. The cover as claimed in claim 12, wherein the walls form a hollow 20 structure extending from the surface part to the lip or lips.

14. The cover as claimed in claim 13, wherein the lip or lips extend around the entire distal edge of the hollow structure. 25

15. The cover as claimed in claim 12, 13 or 14, wherein the wall(s) and lip(s) together form an L-shape in cross-section.

16. The cover as claimed in claim 12, 13 or 14, wherein the at least one wall also includes an outwardly facing lip on its distal edge. 30

17. The cover as claimed in claim 16, wherein the wall(s) and lip(s) together form an inverted T-shape in cross-section. 7

18. The cover as claimed in any one of claims 12 to 17, wherein the reinforcing part preferably includes four walls arranged in a rectangular formation and has four or eight struts connecting the reinforcing part to the peripheral frame. 5

19. The cover as claimed in any one of claims 12 to 17, wherein the reinforcing part includes three walls arranged in a triangular formation and has three struts connecting the reinforcing part to the peripheral frame.

20. The cover as claimed any one of claims 12 to 17, wherein the 1o reinforcing part includes one circular or oval wall and has four struts connecting the reinforcing part to the peripheral frame.

21. The cover as claimed in claim 18, 19 or 20, wherein the strut(s) preferably also connect the reinforcing part to the surface part. 15

22. The cover as claimed in any one of claims 12 to 21, wherein the surface part is substantially solid. Dated 4 May, 2009 20 Patrick Pussell Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON