NZ542317A - Tree grate system - Google Patents

Abstract

The present invention discloses both a grate system, and method, whereby a tree planted in soil which supports a paved or otherwise sealed surface can grow for relatively long periods without disturbing that surface. The tree (1) and its root ball (31) are planted in the soil (2) with an air gap (27) between the upper surface (22) of the soil (2) and a support member (16, 46) which spans an opening (12) in a foundation (10) for the footpath (6) or similar sealed surface. The root ball (31) is able to grow upwardly into the air gap (27) for years without disturbing either the footpath (6) or the support member (16, 46).

Description

54231 PATENTS FORM NO. 5 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION TREE GRATE SYSTEM We, HUB STREET EQUIPMENT PTY LIMITED of 10 Regent Street, Chippendale, New South Wales, 2008, Australia hereby declare the invention for which I/we pray that a patent may be granted to me/us and the method by which it is to be performed, and particularly described in and by the following statement: 5087A-NZ 1 j^pRTYOmCEj SEP 2005 I —BJLCglvpn / The present invention relates to trees growing in soil which supports a paved or otherwise sealed surface. In particular, the present invention relates to trees growing on paved footpaths (or sidewalks as they are referred to in the USA) alongside roads in urban areas.

Trees form a very desirable part of the urban landscape and are much admired and desired for their aesthetic and environmental values. However, tree roots and paved surfaces are to some extent incompatible and it is not unknown in some municipalities for trees which are planted at regularly spaced intervals along the kerb 10 separating a footpath from a roadway, for example, to require some attention every six months or so. In particular, as the tree grows its roots also expand thereby lifting and cracking the pavement alongside the tree. Such a pavement maybe concrete, an asphalt surface, adjoining pavers, and the like. By lifting the paving surface and creating an obstacle for pedestrians, such tree roots constitute a severe risk of injury to 15 the pedestrians and a risk of litigation for the municipal authority responsible for the tree.

As a consequence, there has for a long time been a need for a system of planting such trees where the tree does not so rapidly disturb the pavement and thus 20 can be left unattended for years, rather than months, as with the prior art systems. Further, municipal authorities spend a lot of money planting new trees. A large percentage of these new trees do not establish due to the harsh urban environment in the first three months and then die. This represents a further drain on municipal funds. Thus there is a need for an improved tree grate system.

The object of the present invention is to go at least some way towards meeting the abovementioned needs.

In accordance with the first aspect of the present invention there is disclosed a 30 tree grate system for a tree planted in soil which supports a paved or otherwise sealed surface, said tree comprising a root ball from which a trunk extends upwardly, said system comprising a foundation upon which said paved surface is supported, a opening in said foundation to accommodate said root ball, a structural support member which spans said opening and which includes an aperture through which said 5087A-NZ 2 trunk emerges, said structural support member providing a fovindation for said paved surface located between said aperture and the periphery of said opening, and said structural member and said root ball being vertically spaced apart to provide an air gap therebetween.

In accordance with the second aspect of the present invention there is disclosed a method of growing a tree in soil which supports a paved or otherwise sealed surface, said method comprising the steps of: (i) if necessary, forming an opening in the foundation upon which said paved surface is supported, (ii) if necessary, forming a recess in said soil to accept the root ball of said tree via said opening, (iii) spanning said opening with a structural support member so as to form an air gap which extends vertically between said root ball and said structural support member, said structural support member having an aperture therein through which the trunk of said tree emerges, and (iv) locating a paved surface on said structural support member between said aperture and the periphery of said opening.

A streetscape incorporating the abovementioned tree grate system is also 20 disclosed.

Some embodiments of the present invention will now be described with reference to the drawings in which: Fig. 1 is a cutaway perspective view of a tree incorporating a grate system in 25 accordance with the first embodiment of the present invention, Fig. 2 is a plan view taken at street level of the arrangement of Fig. 1, with part of the paving being cutaway to illustrate the interior construction, Fig. 3 is vertical cross-sectional view taken along the line (III)-(III) of Fig. 2, Fig. 4 is a view similar to Fig. 3 but in respect of an arrangement of a second 30 embodiment, Fig. 5 is an exploded perspective view of the structural support member of the embodiments of Figs. 1-4, Fig. 6 is a view similar to Fig. 1 but of a third embodiment of the present invention, 5087A-NZ 3 Fig. 7 is a view similar to Fig. 2 but in respect of the third embodiment, Fig. 8 is a cross-sectional view taken along the line (XIII)-(XIII) of Fig. 7, Fig. 9 is a cutaway perspective view of a fourth embodiment, and Fig. 10 is a perspective view of the slat array of Fig. 9.

As seen is in Figs. 1-3, in the system of the first embodiment, a tree 1 is planted in soil 2 alongside a road 3 having a gutter 4 and a kerb 5 which extends along one edge of a footpath 6.

The footpath 6 is formed from pavers 8 which are laid on a layer 9 of sand which is in turn supported by a concrete foundation 10. At the location of the tree 1 the foundation 10 is provided with a relatively large opening 12. Embedded in the concrete foundation 10 and forming a peripheral boundary of the opening 12 is a rim 13 including a horizontal lip 14.

As best seen in Fig. 5, the lip 14 of the rim 13 provides a seat for a two part support member 16 which spans the opening 12 and which includes a centrally located aperture 17 through which the trunk 21 of the tree 1 extends. The support member is fabricated in two pieces, each of which has a bight 19. The two bights 19 20 together form the aperture 17. The support member 16 is also provided with small perforations 18 which are of a sufficient size to enable water to drain through the support member 16 and yet still support on the support member 16 the sand layer 9 onto which are positioned paving stones 20 having a configuration which is generally similar to that of a cube. It will be appreciated that the upper surface of the paving 25 stones 20 is flush with the upper surface of the pavers 8 of the footpath 6. The support member 16 is preferably sufficiently strong to enable a single wheel of a vehicle, such as a light truck to be supported by the support member 16.

As best seen in Figs. 1 and 3, the trunk 21 is surrounded with a granular 30 material 23 (such as road base, small pebbles, crumbed rubber, or the like) which substantially fills the space between the aperture 17 and the trunk 21. As best seen in Fig. 3, it will be appreciated that because the support member 16 spans the opening 12, a substantial air gap 27 is able to be present between the upper surface 22 of the soil 2 which covers the root ball 31 of the tree 1. 5087A-NZ 4 A number of substantial advantages flow from the construction illustrated in Figs. 1-3. Firstly, because of the air gap 27 present between the upper surface 22 of the soil 2 and the support member 16, the root ball 13 can expand with time into the air gap 27 without disturbing the flush surface formed by either the paving stones 20 or the pavers 8. It is anticipated that a period of up to 5 years can pass before the support member 16 is in any way dislodged by the root ball 31 and thus some remedial work is called for. This is to be compared with a time period of approximately 6 months with prior art arrangements.

Secondly, moisture is able to percolate between the paving stones 20 and pavers 8 into the sand layer 9 and from there it is able to drip through the air gap 27 and onto the upper surface 22 of the soil 2. This is of considerable assistance in maintaining the tree 1 adequately watered.

Thirdly, the granular material 23 contained within the aperture 17 can be dislodged by expansion of the trunk 21 without in anyway disrupting or unseating the support member 16. Any superfluous granular material 23 is merely washed away during rain events, for example, and forms part of the detritus normally washed down the gutter 4.

If desired, as indicated in Fig. 2, one or more of the paving stones 20 can be removed and a light 30 installed to enable the tree 1 to be illuminated at night. The support member 16 is preferably provided with four holes 36, one in each corner, through which an electrical cable maybe passed in order to supply the light 30. Such an electrical cable (not illustrated) can be located under the footpath 6 and pass through the air gap 27 below the support member 16. In addition, irrigation integrated with the grate is able to be supplied by means of a surface manifold and sub surface piping (both not illustrated) which get water to the base of the root ball.

Turning now to Fig. 4, here a second embodiment of the present invention is illustrated in which the foundation 10 supports a layer of asphalt 38. Between the rein 13 and aperture 17 the asphalt 38 is supported by the support member 16. In all other respects the embodiment of Fig. 4 is substantially the same as the embodiment of Figs. 1-3. 5087A-NZ A third embodiment of the present invention is illustrated in Figs. 6-8. Here the support member takes the form of a support grid 46 which has regularly spaced rectangular windows 48 each of which is sized to mate with, and support, a 5 cobblestone 50 (or porphyry set). The cobblestones 50 are embedded in matrix of sand 59. In addition, in the arrangements of Figs. 6-8 the tree 1 is provided with a tree guard 52 having four legs 53 each of which is dimensioned to be supported by a corresponding one of the windows 48. The cobblestones 50 are surrounded by asphalt 38 in order to provide a flush surface for the footpath 6.

Turning now to Fig. 9, a fourth embodiment is illustrated in which the granular material 23 is replaced by a generally rectangular array 60 of slats 61. The slats 61 are generally T-shaped, preferably fabricated from a strong but flexible material such as polypropylene, and are interconnected by means of clip 62. Each clip 62 is formed 15 from a pair of interconnected opposed channels. The channels are dimensioned to snugly receive the width of the slats 61. The clips 62 are preferably moulded as a single piece from polypropylene also. The clips 62 enable the array 60 to be assembled around the trunk 21 of the tree 1.

The array 60 is illustrated in more detail in Fig. 10 and fits within the aperture 17 and is surrounded by paving stones 20. The array 60 is able to support moderate forces such as those created by a person's footfall. However, the array 60 and slats 61 are able to be moved or deformed over time by the growing trunk and/or roots of the tree 1. This movement can take the form of the clips 62 sliding or the deformation 25 can take the form of the slats 61 bending and/or pivoting in response to mechanical force applied by the roots and/or the trunk. However, unlike conventional cast iron grates, for example, the array 60 and slats 61 do not exert sufficient resistance to deform or restrict the growth of the growing trunk or roots. Prior art grates required regular maintenance such as the removal by grinding of inner rings. This 30 maintenance is entirely avoided by the array 60.

The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the street furniture arts, can be made thereto without departing from the scope of the present invention. 5087A-NZ 6 The term "comprising" (and its grammatical variations), as used herein, is used in the inclusive sense of "having" or "including" and not in the exclusive sense of "consisting only of'. 5087A-NZ 7

Claims (19)

What we claim is:

1. A tree grate system for a tree planted in soil which supports a paved or otherwise sealed surface, said tree comprising a root ball from which a trunk extends upwardly, said system comprising a foundation upon which said paved surface is supported, a opening in said foundation to accommodate said root ball, a structural support member which spans said opening and which includes an aperture through which said trunk emerges, said structural support member providing a foundation for said paved surface located between said aperture and the periphery of said opening, and said structural member and said root ball being vertically spaced apart to provide an air gap therebetween.

2. The system as claimed in claim 1 wherein said opening is provided with a peripheral rim upon which said support member is seated.

3. The system as claimed in claim 1 or 2 wherein said support member comprises a perforated plate.

4. The system as claimed in claim 1 or 2 wherein said support member comprises a grid.

5. The system as claimed in any one of claims 1-4 wherein said support member is formed from two substantially similar pieces, each of which has a bight, said bights comprising said aperture.

6. The system as claimed in any one of claims 1-5 wherein said aperture is substantially filled with granular material without filling said air gap.

7. The system as claimed in any one of claims 1-5 wherein an array of slats substantially fills said aperture.

8. The system as claimed in claim 7 wherein said slats are flexible.

9. The system as claimed in any one of claims 1-8 wherein ancillary services are located in said air gap.

10. The system as claimed in any one of claims 1-9 wherein said paved surface is selected from the group consisting of asphalt, pavers and cobble stones.

11. A tree grate system for a tree planted in soil which supports a paved or otherwise sealed surface, said system being substantially as herein described with reference to Figs. 1, 2, 3 and 5; Figs. 4 and 5, or Figs. 6-8 of the drawings.

12. A streetscape incorporating the system as claimed in any one of claims 1-11. 5087A-NZ 8

13. A method of growing a tree in soil which supports a paved or otherwise sealed surface, said method comprising the steps of: (i) if necessary, forming an opening in the foundation upon which said paved surface is supported, (ii) if necessary, forming a recess in said soil to accept the root ball of said tree via said opening, (iii) spanning said opening with a structural support member so as to form an air gap which extends vertically between said root ball and said structural support member, said structural support member having an aperture therein through which the trunk of said tree emerges, and (iv) locating a paved surface on said structural support member between said aperture and the periphery of said opening.

14. The method as claimed in claim 13 including the further step of: (v) substantially filling the space within said aperture surrounding said trunk with granular material without filling said air gap.

15. The method as claimed in claim 13 including the further step of: (vi) locating an array of slats in said aperture.

16. The method as claimed in claim 15 including the further step of: (vii) forming said slats to be flexible.

17. The method as claimed in any one of claims 13-16 including the further step (viii) fabricating said support member to be permeable to moisture.

18. The method as claimed in any one of claims 13-17 including the further step (ix) locating ancillary services in said air gap.

19. A method of growing a tree in soil which supports a paved or otherwise sealed surface, said method being substantially as herein described with reference to the drawings. of: of: Dated this 12th day of September 2005 INTELLECTUAL PROPERTY OFFICE OF N.Z HUB STREET EQUIPMENT PTY LIMITED BY: 2 o SEP 2005 FRASER OLD & SOHN Patent Attorney for the Applicant RECEIVED 5087A-NZ 9