AU2015101443A4 - Grate - Google Patents

Abstract

A trafficable grate assembly 100 and grate 108 for an opening in a structure comprising a body 112 and a plurality of intersecting load-bearing ribs 124, 126. The body 112 may comprise an upper trafficable surface 114, an opposing lower surface 116, and a plurality of apertures 118 extending between the upper 114 and lower surfaces 116. The plurality of intersecting load-bearing ribs 124, 126 may project from and extend along the lower surface 116 of the body 112. 6979570_1 (GHMatters) P101050.AU.1 BENB C\j 1) C CO ------- w0 _ \J CD' c~co qtr) fl * C~ ( 7- = -= I C\ CC*j 7-0 C')D 4 If3

Description

GRATE TECHNICAL FIELD This disclosure relates to a trafficable grate that has particular, but not exclusive, 5 use in roads, pavements, bike paths, etc. BACKGROUND ART A grate is generally used to cover an opening in a structure (e.g. road, pavement, bike path, etc.) to allow traffic, such as people, animals, vehicles, bikes, etc. to pass across the opening whilst maintaining the ability for fluids (e.g. rainwater) to 10 flow into the opening. Grates are generally formed of a plate structure having a plurality of holes therethrough to allow for fluid flow. In many cases grates must provide a trafficable surface that can withstand traffic loading. As a result, these grates can be heavy and costly. 15 It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country. SUMMARY Disclosed herein is a trafficable grate for an opening in a structure comprising a 20 body and a plurality of intersecting load-bearing ribs. The body may comprise an upper trafficable surface, an opposing lower surface, and a plurality of apertures extending between the upper and lower surfaces. The plurality of intersecting load-bearing ribs may project from and extend along the lower surface of the body. 25 The provision of load-bearing ribs strengthens and stiffens the grate, such that the body (providing the trafficable surface) does not need to perform a load bearing 1 6979570_1 function (or may only require limited load-bearing capacity). The primary function of the body may be to provide the trafficable surface (i.e. allowing vehicles to pass over an opening), whilst the load-bearing function of the grate may predominantly (but not necessarily completely) be performed by the load 5 bearing ribs. Because the body does not need to provide full load-bearing function, its size and weight may be reduced. This may provide a reduction in the overall weight of the grate. In one embodiment the load-bearing ribs may be integrally formed with the body. The body and ribs may optionally be formed of ductile iron. Ductile iron has a 10 superior weight-to-strength ratio than, for example, mild steel. It also generally has greater flexibility and elasticity that mild steel. Thus, with mild steel, more material may be required to achieve similar loadings to a grate formed of ductile steel and to rebound to a permanent set (as can be required by government regulations). 15 In one embodiment the grate may comprise sidewalls projecting from and generally extending around the periphery of the lower surface of the body. These sidewalls may also stiffen and strengthen the grate. Also disclosed is a grate assembly comprising a grate as described above and a mounting frame. The grate may be locatable within and hingedly connected to the 20 mounting frame so as to be pivotable between an open and closed position. In the closed position the grate may cover the opening, and in the open position the grate may allow access into the opening. The grate assembly may further comprise a biasing means configured to apply a biasing force to assist movement of the grate from the closed position to the open position. 25 Thus, the biasing means may make it easier for a user to move the grate from the closed position to the open position (i.e. it may reduce the 'lifting weight of the grate). Also disclosed herein is a grate assembly for positioning at an opening in a structure to support traffic loading over the opening. The grate assembly may 2 6979570_1 comprise a grate comprising an upper trafficable surface, an opposing lower surface, and a plurality of apertures extending between the upper and lower surfaces. The grate assembly may further comprise a mounting frame. The grate may be locatable within and hingedly connected to the mounting frame so as to be 5 pivotable between a closed position and an open position. In the closed position the grate may generally cover the opening, and in the open position the grate may allow access into the opening. The grate assembly may further comprise a biasing means configured to apply a biasing force to assist movement of the grate from the closed position to the open position. 10 Again, the biasing means may make it easier for a user to move the grate from the closed position to the open position (i.e. it may reduce the 'effective' weight of the grate). BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will now be described by way of example only, with reference to 15 the accompanying drawings in which: Figures 1A, 1B and IC are top, bottom and side views of a grate assembly with the grate in a closed position; Figure 1D is a side view of the grate assembly with the grate in an open position; 20 Figures 1E and 1F are perspective view of the grate; and Figures 1G and 1H are top and bottom views of the grate. DETAILED DESCRIPTION In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative 25 embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope 3 6979570_1 of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this 5 disclosure. Figures 1A, 1B, IC and ID show an embodiment of a trafficable grate assembly 100 that is suitable for e.g. covering the entrance to a drain located in a road or path so as to allow traffic (e.g. vehicles, bicycles, people) to travel across the 10 drain. The grate assembly comprises a mounting frame 110 and a grate 108, formed of ductile iron, that is located within the mounting frame 110. The grate 108 comprises a body 112 having a generally planar upper trafficable surface 114 that, in use, lies generally flush with the ground (e.g. road) and supports vehicles, 15 bicycles, people, etc. as they pass over the grate 108. In the illustrated embodiment, the upper surface 114 comprises a bicycle tyre penetration resistance (BTRP) anti-skid surface pattern to provide grip for bicycle traffic passing across the grate 108. In other embodiments the upper surface 114 may comprise various other surface patterns, which may be adapted for specific purposes. 20 The body 112 further comprises a generally planar lower surface 116 that opposes and is generally parallel to the upper surface 114, such that the body 112 has a rectangular box- or plate-like form. A plurality of square-shaped apertures 118, in a generally rectangular array, extend between the upper 114 and lower 116 surfaces. These allow fluid to flow through the body 112 and into the opening, in 25 use. The apertures 118 in the illustrated embodiment are sized and shaped such that a bicycle may pass across the upper surface 114 without getting caught in one of the apertures 118. It should be appreciated that in other embodiments the apertures may be shaped and sized differently depending on the application of the embodiment. 4 6979570_1 The apertures 118 are defined by evenly spaced laterally 120 and longitudinally 122 extending beams that intersect so as to form a lattice structure. The upper edges of these beams 120, 122 generally define the upper surface 114 of the body 112. The upper edges of the lateral beam 120 are castellated so as to form the 5 anti-skid surface pattern discussed above. The lower edges of the beams 120, 122 define the generally planar lower surface of the body 112. The grate 108 comprises a plurality of intersecting load-bearing ribs 124, 126 that project from, and extend along, this lower surface. In particular, the grate 108 comprises two parallel longitudinal load-bearing ribs 124 10 and two parallel lateral load-bearing ribs 126. The ribs 124, 126 are integrally formed with the body (i.e. to form the grate 108) and intersect at a central portion of the lower surface 116. The ribs 124, 126 provide load-bearing support to the body 112 to enable the grate 108 to withstand traffic loading. That is, the provision of load-bearing ribs 124, 15 126 strengthens and stiffens the grate 108, such that the body 112 (providing the trafficable surface) does not need to perform a load bearing function (or may only require limited load-bearing capacity). In other words, the primary function of the body 112 is to provide the trafficable surface (i.e. allowing vehicles to pass over an opening), whilst the load-bearing function of the grate 108 is predominantly 20 performed by the load-bearing ribs 124, 126. Because the body 112 does not need to provide full load-bearing function, its size and weight may be reduced (i.e. as is the case with the illustrated embodiment). This may provide a reduction in the overall weight of the grate assembly 100. To further facilitate a reduction in weight of the grate assembly 100, the load 25 bearing ribs 124, 126 are thinner (i.e. they project a small distance from the lower surface 116) at their ends, and are thicker at their centres, where the body 112 spans across the opening (and where more stiffness is required). At their ends, the load-bearing ribs intersect with tapered sidewalls 128 that project from and extend partway around the periphery of the lower surface 116 of the body 112. These 5 6979570_1 sidewalls 128 provide further stiffness to the grate 108 and, in use, their lower edges rest upon, and are supported by, the frame 110. The mounting frame 110 has an open-topped (and partially open-bottomed) box form. It comprises four sidewalls 130 that extend around the body 112 when 5 received therein, and a base portion formed by flanges 132 extending perpendicularly and inwardly from lower edges of the sidewalls 130. It is these flanges 132 that the sidewalls 128 of the body 112 rest upon and are supported by when the body 112 is located within the mounting frame 110. The mounting frame 110 of the illustrated embodiment has a depth of 10 approximately 90 mm. This dimension is equivalent to that set out in the Australian standards for grate sizing. As such, the mounting frame 110 may suitably fit within existing pre-cast concrete designs. The grate 108 and the frame 110 are hingedly connected at a rear edge, such that the grate 108 is able to pivot relative to the frame 110 between open and closed 15 positions. This hinged connection comprises opposing pins 134 that project outwardly from sidewalls 128 of the body 112 proximate the rear edge of the body 112, and that project through corresponding apertures 136 (i.e. forming knuckles of the hinge) in the mounting frame 110. Although not apparent from the figures, each pin 134 supports a biasing means in 2 0 the form of a torsion spring 140 that provides a biasing force between the grate 108 and the mounting frame 110. The direction of the biasing force is such that it urges the grate 112 from the closed position to the open position 110. The operation of the biasing means force will be described in more detail below. Figures 1A, B and C show the grate 108 in the closed position. In this position, 25 the body 112 is located within the mounting frame 110, such that it covers an opening (over which the grate 108 is positioned). Although the direction of the biasing force is such that it urges the grate 108 towards the open position, the torsion springs 140 are configured such that the strength of the biasing force is unable to overcome the weight of the grate 108. Hence, the weight of the grate 6 6979570_1 108 is enough to maintain the body in the closed position (i.e. a latch assembly is not required to hold the grate 108 in the closed position). Nevertheless, the grate 108 can be further secured in the closed position by way of a locking assembly 138 (for example, where the grate is partially lifted by the torsion springs so as not 5 to be flush with the ground). This locking assembly 138 comprises a bolt, a bolt receiving aperture in the body 112, and a threaded bolt-engaging recess in the mounting frame 110. To secure the grate 108 in the closed position, the bolt is received through the aperture in the body 112 and then engaged with the recess in the mounting frame 110. The head of the bolt abuts the upper surface 114 of the 10 body 112 to secure the grate 108 in position. Figure ID shows the grate 108 in the open position. In this position, the grate 108 is pivoted away from the mounting frame 110 such that access (e.g. by a worker) is provided into the opening covered by the grate assembly 100. To facilitate pivoting of the grate 108, the body of the grate comprises two keyhole lifting 15 rebates 142. In use, a user can insert a lifting key (having a boss that corresponds to the lifting rebates) into one of the rebates and lift the grate using the lifting key. The rebates 142 may be adapted so as to be suitable for a standardised lifting key. The biasing force of the torsion spring 140 assists the pivoting of the grate 108 from the closed position to the open position. That is, the torsion spring 140 20 reduces the force required to open the grate 108. Variations and modifications may be made to the parts previously described without departing from the spirit or ambit of the disclosure. For example, the locking mechanism may comprise a camlock mechanism, rather 25 than a bolt arrangement. The cam-lock mechanism may comprise a barrel that is rotatable by a key and which is connected to a retainer that projects laterally from, and rotates with, the barrel. In order to lock the grate in the close position, a user may rotate the barrel using the key, which causes the retainer to be rotated so as to project under a portion of the frame. The retainer then abuts the underside of the 7 6979570_1 frame and prevents the grate from pivoting upwards (e.g. due to the biasing force). To unlock the cam-lock mechanism, the user can turn the key in the opposite direction to move the retainer out of engagement with the frame. The key may be a lifting key. That is, the barrel may be adapted for receipt of the end of a lifting 5 key, such that the lifting key is used to rotate the barrel to lock and unlock the locking mechanism. In this way, the user can make use of the same tool to unlock and lift the grate. The body may be hexagonal, circular, etc. rather than rectangular in shape. Similarly, the apertures through the body may be triangular, circular, hexagonal, 10 etc. The apertures on a body may also vary in size and shape. The shape, size and number of load-bearing ribs may vary. The ribs may, for example, be curved. The size of the frame may vary. For example, the depth of the frame may be between 85 mm and 95 mm, or between 50 mm and 150 mm. 15 Other forms of biasing means (i.e. other than one or more torsion springs) may be used to assist pivoting of the body from the closed position to the open position. For example, one or more compression springs, leaf springs, elastic members, etc. may be used at the hinged joint. In the claims which follow and in the preceding description of the invention, 20 except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 25 8 6979570_1

Claims (5)

1. A trafficable grate for an opening in a structure comprising: a body comprising an upper trafficable surface, an opposing lower surface, and a plurality of apertures extending between the upper and lower 5 surfaces; and a plurality of intersecting load-bearing ribs projecting from and extending along the lower surface of the body.

2. A grate as claimed in claim 1 wherein the load-bearing ribs are integrally formed with the body, the body and ribs optionally being formed of ductile iron. 10

3. A grate as claimed in claim 1 or 2 comprising sidewalls projecting from and generally extending around the periphery of the lower surface of the body.

4. A grate assembly comprising: a grate as claimed in any one of the preceding claims; a mounting frame, the grate locatable within and hingedly connected to the 15 mounting frame so as to be pivotable between: a closed position in which it generally covers the opening; and an open position, in which it allows access into the opening; and a biasing means configured to apply a biasing force to assist movement of the grate from the closed position to the open position. 20

5. A grate assembly for positioning at an opening in a structure to support traffic loading over the opening, the grate assembly comprising: a grate comprising an upper trafficable surface, an opposing lower surface, and a plurality of apertures extending between the upper and lower surfaces; and 9 6979570_1 a mounting frame, the grate locatable within and hingedly connected to the mounting frame so as to be pivotable between: a closed position in which it generally covers the opening; and an open position, in which it allows access into the opening; and 5 a biasing means configured to apply a biasing force to assist movement of the grate from the closed position to the open position. 10 6979570_1