AU2007247782B2 - Two-part turf pallet with interconnected components - Google Patents

Abstract

A pallet for natural or artificial turf comprising a structure moulded in foamed plastics to have a closed planar top surface supported by a lattice work of mutually perpendicular walls defining a flexible open base, the structure defining a pair of elongate spaced parallel channels extending across each side to facilitate forklift tine entry.

Description

WO 2007/128078 PCT/AU2007/000617 TWO-PART TURF PALLET WITH INTERCONNECTED COMPONENTS This invention relates to a pallet specifically for use in supporting natural and artificial turf. 5 Introduction In a modern day sporting stadium there is an ongoing need for multi purpose facilities. When used for sporting occasions there is a need for a surface that is usually 10 made of natural turf, though in certain circumstances sport fields include artificial turf. Sometimes a sporting field can have a central playing section of natural turf surrounded by artificial turf boundaries. There is often a need to move the turf thereby exposing a 15 concrete base which can then be used to stage concerts, motoring events or even be used as a car park. The turf can be removed to, in the case of natural turf, facilitate growing, watering and regeneration of the turf and in the case of artificial turf, to facilitate maintenance and 20 avoid damage. Although early versions of synthetic/artificial turf could be easily rolled up and removed, later versions that include a rubber/sand infill cannot be rolled up. 25 This need to constantly remove and reposition turf of both types requires a mechanism to aid the lifting and transportation of the turf products. One means of providing this aid is to provide pallets or 30 trays on which the turf can be placed. The pallets or trays support the turf in use whilst providing a facility for transportation of the turf. Turf pallets need to provide the desired support for the turf product whilst at the same time have the necessary strength and durability 35 to facilitate lifting and transportation. The strength, durability and weight of such pallets are important criteria that have brought about the present invention.

-2 Summary of the Invention According to the present invention there is provided a liftable support platform adapted for the dual role of supporting a layer of natural turf or artificial turf and infill above a foundation, the platform comprising: a 5 structure moulded in foamed plastics to have sides between 1250 and 2700mm in length, the structure having a closed planar top surface adapted to support the layer of turf above the foundation, said top surface being provided with specifically positioned drainage holes adapted for draining water which has drained through the layer of turf thereabove; a latticework which supports 10 the top surface and hence the layer of turf, said latticework having mutually perpendicular walls defining a flexible open foundation engaging planar base; the structure further having a pair of elongate spaced parallel wall channels extending across each side of the planar base of the lattice work to facilitate forklift tine entry therein and lifting of the support platform 15 and layer of turf; the platform having edge retainers fixed to the sides of the structure, the edge retainers having an upper edge above the top surface of the platform to define an enclosure to prevent escape of the natural turf or artificial turf infill, and each corner of the platform having a slot across adjacent edges adapted to accommodate means to join adjacent platforms 20 in abutting contact and prevent the corners arching upwardly in use. Preferably the pallet is moulded in two halves joined to form a square or rectangle, the join being about a diagonal. 25 In one embodiment, the join between the mould halves includes a plurality of spaced male projections in one mould half that are arranged to be accommodated in a plurality of similarly spaced female recesses in the other mould half. In a preferred embodiment fasteners are used to join the male projections to the female recesses. 30 The pallet is preferably constructed from commingled plastics, foamed through the use of Nitrogen gas. The plastic is preferably high density polyethylene. 35 In a preferred embodiment each corner of the pallet is located on a locator plate that facilitates the location of one corner of four adjacent pallets. 3658250_ 1 (GHMatters) P60156.AU.1 4/0912 WO 2007/128078 PCT/AU2007/000617 -3 Description of the Drawings Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which: 5 Figure 1 is a plan view of a pallet for supporting natural or artificial turf supported in two opposite corners by locator plates; 10 Figure 2 is a side elevational view of the pallet and location plate; Figure 3 is a cross sectional view taken along the lines A-A of Figure 1; 15 Figure 4 is a plan view of one mould section that forms half of the pallet; Figure 5 is one side elevational view of the mould 20 section; Figure 6 is the other side elevation view of the mould section; 25 Figure 7 is a plan view of an edge retainer that forms part of the pallet; Figure 8 is a side elevational view of the edge retainer; 30 Figure 9 is an end on view of the edge retainer; Figure 10 is a plan view of a locator for the corner of the pallet; and 35 Figure 11 is a side elevation of the locator; WO 2007/128078 PCT/AU2007/000617 -4 Figure 12 is a cross sectional view of an alternative edge section for the pallet with the retaining edge integrally formed with the pallet; 5 Figure 13 is a similar cross sectional view showing the pallet formed without an edge with the facility to screw on a detachable retaining edge; Figure 14a is a partial view of a pallet illustrating the 10 provision of a slot that can accommodate a removable edge strip; Figure 14b is a schematic illustration of a variation on that theme; 15 Figures 15a and 15b are plan and side elevational views of a mechanism for securing edges of adjacent pallets together; 20 Figure 16a is a plan view of a pallet illustrating the location for vertical lifting; Figure 16b is a side elevational view of a tool for use in vertical lifting; 25 Figure 1Gc illustrates the design and location of sockets in the pallet to accommodate the tools shown in Figure 16a; and 30 Figures 17a, 17b and 17c are schematic illustrations of another mechanism for lifting the modules from above. Description of the Preferred Embodiments As shown in the accompanying drawings a pallet 10 for use 35 to support natural or synthetic turf is moulded in foamed plastics in two halves 11, 12 that are joined about a diagonal 13. The pallet 10 is square in plan to define an WO 2007/128078 PCT/AU2007/000617 -5 upper surface 20, under surface 21 and sides 22, 23, 24, 25. Each side of the pallet has detachable secured thereto an edge retainer 50 to define the completed pallet and each pallet is arranged to sit on appropriately 5 positioned locators 70 that engage a corner of the pallet 10. It is however understood that the pallet may be moulded as a single piece with or without edge retainers. Thus, 10 depending on the end use of the pallet it can be moulded to have no edge retainers at all. Alternatively, it can be moulded so that fixed edge retainers are integrally formed in the pallet or it can be moulded as shown in Figures 1 to 9 whereby edge retainers 50 can be detachably 15 secured thereto. Further details on the edging systems are described later in the specification. The pallet is preferably moulded in either one or two pieces to define a square that is 2250mm. It is 20 understood however that the square could be larger such as 2400 mm or in some circumstances it is understood that the pallet would be considerably smaller such as a 1250mm square. Essentially, the pallet is usually square, although it can be rectangular, and has side dimensions 25 varying between 1250mm and 2700mm. As described above each pallet comprises two halves 11, 12 that are joined together. One half is shown in Figures 4, 5 and 6 and comprises a top side 22 and an edge side 23 30 joined by a diagonal 13 that has a pair of spaced recesses 14, 15 and a pair of spaced projections 16, 17. The first recess 14 defines four slots 18 and the second recess 15 has three slots 19. The first projection 16 near the centre of the mould half 11 has three projecting fingers 35 26 and the second projection 17 towards the edge of the mould half has four projecting fingers 27. The projecting fingers 26, 27 are arranged to be a sliding fit within the WO 2007/128078 PCT/AU2007/000617 -6 slots 18, 19 of the other mould half and fasteners in the form of countersunk bolts 28 and nuts 29 allow the two mould halves to be bolted together to form the square pallet shown in Figure 1. The lower edge 23 of the mould 5 half 11 shown in Figure 6, has a completed corner whilst the other edge 22 of that mould half has an incomplete corner which would be completed by the corner of the other mould half so that about the diagonal one corner is defined by one mould half 11 and the other by the other 10 mould half 12. Each mould half 11 or 12 has a substantially planar upper surface 20 that is supported by a plurality of mutually perpendicular latticework walls 30, 31 that extend down to 15 an open base structure 21. This wall structure is shown with particular reference to Figures 5 and 6. The density of the lattice work wall structure provides adequate support for the planar surface 20 of the pallet 10 and that surface is provided with a plurality of drainage 20 holes 35 that are usually tapered in cross section and are located centrally of each lattice work section as shown in Figure 4. The mould halves 11, 12 are also reinforced by a series of elongate parallel wall structures 36 that are positioned in spaced apart clusters to define as shown in 25 Figure 6 the reinforced walls 37 of rectangular slots 38 that extend along the length of the pallet from both sides to define a pair of spaced parallel slots 38, 39 for access of forklift tines. The top edge of Figure 4 shows how the reinforced wall structure of each tine slot is 30 slightly flared outwardly to facilitate tine entry. In the embodiment of Figures 1 to 9, each side of the pallet 10 is reinforced by an edge retainer 50 shown in Figures 7-9, The edge retainer 50 comprises a vertical 35 wall 51, the upper half 52 of which is part of the peripheral rim of the pallet 10 and the lower half 53 of which includes an aperture 54 through which a fastener can WO 2007/128078 PCT/AU2007/000617 -7 enable the edge retainer 50 to be screwed to the edge of the pallet 10. Thirteen fasteners secure each edge retainer 50 to the pallet mould halves. The vertical wall 51 of the edge retainer has a horizontally projecting web 5 55 on one side with a downwardly extending lip 56 that clips against the edge of the mould halves 11, 12. As shown in the plan view of Figure 7, the opposite ends of the edge retainer 50 is tapered inwardly at 450 to enable the edge retainers to join in a bevelled fashion at the 10 corners as shown in Figure 1. The upper half 52 of the wall 51 extends above the upper surface of the mould halves by 81mm to accommodate and locate natural turf that it located in the pallet. 15 In the embodiment shown in Figures 1 to 9, the pallet 10 is moulded to have detachable edge retainers 50. It is however understood that the pallet could be moulded to have no edge retainers at all as shown in Figure 14a or to have a fixed integrally formed edge retainer 101 shown in 20 Figure 12 or as a base unit 104 to facilitate attachment of an edge retainer 102 through screws 103 as shown in Figure 13. In the embodiment that has no edge retainer shown in Figures 14a and 14b, the pallet 105 is moulded to have an inbuilt slot 106 that is inclined at 150 to the 25 vertical inboard of the side edge of the pallet and to be approximately 25mm in depth with a width of 2mm. The slot 106 is arranged to accommodate a thin Mylar' m strip 110 that is approximately 0.7mm in thickness. The strip 110 is 55mm deep so that 30mm of the strip extends upwardly of 30 the top surface of the pallet 105 at an angle of 150. A 1mm HDPE retaining strip 111 30mm in depth protrudes 6mm above the top and is screwed to the Mylar" strip by three retaining screws 112 shown in Figure 14a. In another embodiment shown in Figure 14b, a folded strip 115 of 35 Mylar" having a 30mm, 150 upward projection is secured to the top surface of the pallet 105 by staples 109. In both cases, this pallet 105 is used to support artificial turf WO 2007/128078 PCT/AU2007/000617 that extends to a height of 62mm above the top of the pallet with an infill of sand and rubber being 40mm in depth. The Mylar" strip 110 prevents escape of the infill when the pallet 105 is transported. 5 Each corner locator 70 is shown in Figures 10 and 11 and comprises a planar surface 71 that has a central crossed pair of raised walls 72, 73 and in each corner a frusto conical stud 74. As shown in Figures 1 and 2, the corner 10 of the pallet 10 engages within the open channel defined by the raised walls 72, 73 the frusto-conical stud 74 locates in a recess 75 in the underside of the pallet 10. In this way, each locator can accommodate the four corners of four adjacent pallets that are positioned in close 15 proximity to each other. The raised walls 72, 73 of each locator 70 thus defines the spacing of the pallets that varies slightly for natural and synthetic turf. The pallet halves and the locators, as well as the edge 20 retainers, are moulded in foamed HDPE. As shown in Figure 6 the upper surface 20 of the pallet 10 is provided with tapered drainage holes 35 positioned adjacent the wall structures and towards the centre of 25 each lattice work structure. The upper surface 20 also includes carpet dimples 45 to assist in location of synthetic turf. Synthetic turf is usually in the form of a nylon carpet with tufts located in a base structure. It is usual to fill the carpet with an aggregate of sand and 30 rubber to define the playing surface. When the pallet is used with natural turf, a fine cloth is usually placed over the upper surface 20 of the pallet 10 onto which the turf product can be directly laid. The natural turf usually comprises a grass root zone on a layer of 35 sand/peat reinforced with plastics mesh inserts known as Re Flex®. The pallet 10 is usually 140mm in depth and the natural turf extends to a further 125mm above the upper WO 2007/128078 PCT/AU2007/000617 -9 surface of the pallet. The upstanding walls of the edge retainers 50 support natural turf for 81mm. The artificial turf is usually 50mm-60mm above the upper surface 25 of the pallet 10 and it is thus understood 5 that, when used with both artificial and natural turf, suitable lifting means may have to be incorporated within the pallet to raise it to the height to ensure that the artificial turf is at the same level as the natural turf. The pallet 10 when unladen weighs approximately 701bs and 10 the pallet is designed to be a square of 2.29 metres. The pallet is preferably constructed from structural foam using commingled plastics, foamed through the use of Nitrogen gas. The commingled plastics is a mixture of 15 some or all of the following: High Density Polyethylene (HDPE), Low Density Polyethylene, Polypropylene, fibres, ABS, and long fibres for reinforcement. The pallet when unladen weighs approximately 70lbs to 1501bs depending on the plastics mixture used and the pallet is designed to be 20 a square of 2.29 metres. The pallet described above is moulded in foamed plastics using lancing technology. Nitrogen gas is used to expand the plastics to produce a micro cellular arrangement, thereby substantially lightening the structure. This technique also allows the 25 use of commingled plastics. High Density Polyethylene (HDPE) is viewed as the most suitable plastics and this provides a structure that is sufficiently strong to withstand the loads that will be subjected to both natural and artificial turf. The plastics can have the gas 30 mixture varied to enhance impact, strength and flexibility. The plastics can also be recycled plastics. The lattice work structure defined by the wall structure of the pallet halves provides a good drainage facility 35 whilst excellent aeration for the root structure of natural turf that may be located above the pallet. The open structure of the underside of the pallet ensures that WO 2007/128078 PCT/AU2007/000617 - 10 there is no likelihood of the pallet aquaplaning on a smooth surface. The pallets described above have to satisfy two important 5 criteria, namely the structures need to be sufficiently flexible to ensure that they lay flat on the support surface that is usually a slab of concrete. This is especially the case when used to support artificial turf that is considerably lighter than natural turf. With 10 artificial turf, it is very important that the corners of each pallet do not arch upwardly. It is also important that there is no wobble. To solve this problem it is proposed in the embodiment shown in Figures 15a and 15b to provide slots 120 in the adjoining edges of the four 15 adjacent pallets 10 that make up a corner to accommodate a pin 121 that extends across the edges of the four pallets and prevents the edges of the pallets arching upwardly at the join. The slots would be approximately 10mm wide and 25mm deep to extend about 155mm in length. 20 Slots may also be positioned midway along the sides of each pallet and circular locking discs may be used instead of the pins to lock four adjacent corners in the manner shown in Figure 15(a) or to allow panels to be in offset 25 rows like brickwork with the disc engaging two adjacent corners of pallets in one row and the middle of the side of one pallet in the adjacent row. The open structure of the underside of the pallet provides 30 a flexible construction that can accommodate the uneven and possibly rough surface of the supporting substrate that is usually a concrete slab. The moulding of the pallet in a foamed plastic can by variation of the mix increase this flexibility to ensure a flat even support 35 without the problem of wobbling.

WO 2007/128078 PCT/AU2007/000617 - 11 Another important characteristic of turf assemblies of the kind described above is the impact resistance, especially when used with sports such as the various kinds of football i.e. soccer, football or rugby. There is a known 5 impact resistance test that is measured by a cleg hammer tested with a 2.25kg hammer at a drop height of 450mm. This impact resistance is measured in gravity units and it is generally viewed that an acceptable impact resistance is between 40-70 gravity units whilst resistance of 110 or 10 more is too severe and likely to cause injury. The tests have been carried out to compare the impact resistance from the following combinations: a) turf carpet directly on a concrete surface; 15 b) turf carpet on a rubber underlay on a concrete surface. This underlay was designed to be substantially similar to the underlay that is used in some artificial turf layouts; 20 c) carpet on a plastics pallet of the kind described above sitting directly on a concrete surface (1) with the impact resistance being directly against the plastic rib supports and 25 (2) with the impact resistance being measured between the supports. The results for three clegg hammer drops are illustrated in the following table: 30 Hammer Drops 1 2 3 a 80 90 90 b 50 50 50 C 1 40 40 40 C 2 30 30 30 WO 2007/128078 PCT/AU2007/000617 - 12 It is thus concluded that the impact resistance of artificial turf when supported by pallets of the kind described above will be between 30 and 40; well within the desired range. Tests have also been carried out on 5 natural turf modules that are between 100-120mm thick turf squares sitting directly on concrete and these produce an impact range of between 55-60 gravity units. Since it is desired to manufacture the turf pallets in plastics that provide a greater degree of flexibility than would be the 10 case of a plastics pallet design for artificial turf, it is considered that the impact resistance for natural turf on such pallets would be unlikely to be higher than 40 units. 15 The use of slots extending across both sides of the pallet ensure ready forklift tine access for lifting of the pallet and turf assemblies and it is understood that the pallet can be further modified to facilitate vertical lifting through either direct contact with the pallet or 20 contact into the turf which is in turn attached to the pallet to cause the assembly to be lifted. Figures 16 and 17 illustrate mechanisms that facilitate vertical lifting. In Figure 16a each pallet is provided with a lifting lug connection 130 in each corner of the pallet. Two options 25 of the lug connection 130 are shown in Figure 16c that can be either between a cross web and a side flange in the join between the web and the side flange. Figure 16b shows a tool 131 that has a handle 132 that is joined to an elongate shaft 133 that terminates in a head 135. The 30 head has a T shaped end to enable it to be inserted into the locator 130 and then turned through 900 to engage the underside of the locator. With four such tools engaging each corner of the pallet 10 it is possible to lift the pallet 10 and turf product without the use of forklift 35 tines.

WO 2007/128078 PCT/AU2007/000617 - 13 In the embodiment shown in Figures 17a, 17b and 17c there is a cork screw style device 210 that has a annular end 211 that is adapted to engage a bar 212 by screwing the corkscrew style device into the turf 222 the coils of the 5 screw engage and grip the turf 222 and then by placing the bar 222 through a series of these devices 210 that are arranged in parallel and lifting the bars the whole turf product can be lifted either clear of the pallet or, if the turf is attached to the pallet, with the pallet. It 10 is also understood that the corkscrew device 210 instead of simply screwing into the turf could, in certain circumstances, screw through the turf to engage the pallet thereby ensuring lift of both the pallet and the turf without necessarily having to attach the turf to the 15 pallet. The pallet structure described above is sufficiently light yet durable to withstand the impacts and stresses of use, to provide ready support for the turf when used as a 20 playing field whilst at the same time providing a means for facilitation transportation and storage of turf, especially natural turf which can be transported to a suitable site for regrowth. 25 The versatility of the pallet described above especially with its capacity to support natural and or artificial turf and the capacity of individually identifying each pallet and storing this information in a computer allows a stadium to manage the placement of its turf. The computer 30 can monitor the use time and wear assessment of the turf and select appropriate pallets for movement to even out wear characteristics and maximize utilization of the total field. Movement of the pallets also facilitates offsite application of lines or coloured images such as sponsor's 35 logos prior to installation in the stadium.

WO 2007/128078 PCT/AU2007/000617 - 14 It is understood that the system facilitates the ability to pick up and move pallets as desired, thus when a stadium is for multipurpose use all the turf can be 5 removed exposing the concrete base for concerts and like entertainment and when there is a need for sporting venue the turf can be moved back to the stadium, In the interim the artificial turf can be stacked in racks and the natural turf can be taken to a position of optimum growth. 10 The design of the pallets is such that natural turf can be left on the pallet and stored with adequate drainage being provided under the pallet to provide optimum growth especially in an environment that encourages growth in 15 contrast to environments usually provided by a stadium where cantilevered stands block out sunlight and retard growth of natural turf. A sophisticated conveyor system is envisaged that would 20 automatically transport the pallets to both a racked storage facility for artificial turf and a nursery position for natural turf. However it is considered that the turfing option described above allows stadiums to be designed without the need to have roof systems that can 25 open and close. These systems are very expensive to build and to maintain and are merely a compromise. A closed roof provides the optimum conditions for stadium use and with the ability to simply and effectively remove the turf the problems associated with a closed roof are overcome. 30 It is estimated that installation of natural turf can be completed within twelve hours using pallets of the kind described above and it similarly takes about eight hours to totally remove the turf units allowing the stadium to - 15 be used for other functions that would be based on the underlying concrete floor. The use of pallets with edge retainers to support artificial turf 5 substantially enhances the ability to move and transport artificial turf which is usually impossible because the turf is in long rolls which once spread out across the concrete base are then filled with an infill fill of sand and rubber which means that the sand and rubber infill has to be removed before the turf can be rolled up. With 10 pallets bordered by edge retainers which can be butted together the artificial turf can be removed in squares without loss of the infill thus rendering stadiums that use such turf considerably more versatile. 15 In the claims which follow and in the preceding description of the invention, 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 20 preclude the presence or addition of further features in various embodiments of the invention. 3498214_1 (GHMatters) P60156.AU.1 som2

Claims (14)

1. A liftable support platform adapted for the dual role of supporting a layer of natural turf or artificial turf and infill above -a 5 foundation, the platform comprising: a structure moulded in foamed plastics to have sides between 1250 and 2700mm in length, the structure having a closed planar top surface adapted to support the layer of turf above the foundation, said top surface being provided with specifically positioned drainage 10 holes adapted for draining water which has drained through the layer of turf thereabove, a latticework which supports the top surface and hence the layer of turf, said latticework having mutually perpendicular walls defining a flexible open foundation engaging planar base, 15 the structure further having a pair of elongate spaced parallel wall channels extending across each side of the planar base of the lattice work to facilitate forklift tine entry therein and lifting of the support platform and layer of turf, the platform having edge retainers fixed to the sides of the 20 structure, the edge retainers having an upper edge above the top surface of the platform to define an enclosure to prevent escape of the natural turf or artificial turf infill, and each corner of the platform having a slot across adjacent edges adapted to accommodate means to join adjacent platforms in abutting contact and prevent the 25 corners arching upwardly in use.

2. The support platform according to claim 1, wherein the edge retainers are secured to the structure through use of a plurality of spaced fasteners. 30

3. The support platform according to claim 1, wherein the structure is moulded so that the edge retainers form an integral part of the structure. 35

4. The support platform according to claim 1, wherein the edge retainers comprise thin sheets of plastics that project from elongated slits in the upper surface of the structure, the slits being 3658250_1 (GHMatters) P60156.AU.1 4109/12 - 17 positioned so that the edge retainers diverge outwardly from the sides of the structure.

5. The support platform according to any one of the preceding claims, 5 wherein the structure is moulded in two halves joined to form a square or rectangle, the join being about a diagonal.

6. The support platform according to claim 5, wherein the join between the mould halves includes a plurality of spaced male projections in 10 one mould half that are arranged to be accommodated in a plurality of similarly spaced female recesses in the other mould half.

7. The support platform according to claim 6, wherein fasteners are used to join the male projections to the female projections. 15

8. The support platform according to any one of the preceding claims, wherein the structure is constructed from commingled plastics, foamed through the use of Nitrogen gas. 20

9. The support platform according to claim 8, wherein the plastics is high density polyethylene.

10. The support platform according to any one of the preceding claims, wherein each corner of the support platform is located on a locator 25 plate that facilitates the location of one corner of four adjacent support platforms.

11. The support platform according to any one of the preceding claims, wherein the structure includes spaced lifting points. 30

12. An array of support platforms of the kind claimed in any one of the preceding claims, wherein the support platforms abut end to end and side by side and corner locators hold the corners of four adjacent support platforms. 35

13. A turf module comprising a support platform according :o any one of claims 1 to 12, wherein the top surface of the support platform 3658250_1 (GHMatters) P60156.AU.1 4109/12 - 18 supports a slab of natural turf or an area of artificial turf and infill.

14. A sporting or entertaining arena comprising: 5 a pre-prepared substrate; and a plurality of turf modules according to claim 13 positioned on the substrate abutted end to end and side by side to define the operative surface of the sporting or entertaining arena, the turf modules being removable and interchangeable to accommodate wear of the 10 operative surface. 3658250_1 (GHMatters) P60156.AU. 1 41No/12