Where applicable, the utility surface will be referred to as an "activity surface" which embraces, inter alia, an area constructed and arranged for the performance of a particular human activity, especially the playing of a sport or game. The invention will particularly be exemplified in relation to a soccer pitch.

A soccer pitch is an example of an activity surface which, by virtue of its intended use and disposition, is of large surface area and subject to extreme wear and tear both by the users and by exposure to the natural elements. Traditionally, a soccer pitch comprises an area of natural living grass, although artificial pitches have been known for some time. This traditional type of soccer pitch suffers from a number of disadvantages. The material of the playing surface, whether it be natural or artificial grass, is normally permanently disposed on an area of ground where it is intended for its planned use. In such a disposition, unless it is covered by some protective means, such as a tarpaulin, it will be exposed to the natural elements. Whether or not

temporarily covered by a protective cover, this permanent disposition complicates the procedures of normal maintenance and incurs a high background cost element. Further, the underlying area of ground cannot usually be employed for any other activity.

Regular maintenance of the material of the playing surface needs to be carried out regardless of prevailing weather conditions and there will often be a need for a protective covering in order, for example, to reduce the risk of waterlogging due to excessive precipitation. The labour costs incurred in the overall management and care of such a pitch are considerable. Moreover, should a specific proportion of the playing area require longer term or more intensive maintenance, complications may arise from the need to continue to provide the playing area for use, in which case it may be difficult or impossible to provide an optimum condition of playing surface overall throughout the entirety of the normal soccer season. Clearly, in certain areas of the pitch, such as the goalmouths, a worsening condition of the playing surface may pose serious problems of pitch management.

In GB-A-2290239, there is disclosed a utility surface comprising, inter alia, a plurality of trays each filled to an appropriate depth with soil having, say, grass growing thereon and being in juxtaposition with each other, to provide a grass playing area or other activity surface. Each tray may have an upper portion of at least one side wall thereof detachable from or otherwise movable, such as pivotable, with respect to a fixed lower portion of the side wall, with a flexible membrane or other lining, possibly porous, disposed within the tray and having a portion

lying adjacent the or each side wall, preferably adjacent the upper portion thereof. In an embodiment of tray disclosed in the above-referenced patent application, soil or other filling material is placed in the internally-lined tray to a level approximate the lower edge of the detachable or otherwise movable upper portion of the or each side wall, with the grass growing in the soil or other filler at a height just above the upper edge of the detachable or otherwise movable upper portion of the or each side wall. The periphery of the grass growing in the soil or other filling material is thus contained within the upper region of the flexible member. When a plurality of the utility surface trays are being assembled side-by- side, the detachable or otherwise movable upper side wall portions of adjacent trays are detached from or otherwise moved with respect to the fixed lower side wall portions of the trays and the thus-exposed upper portions of the flexible membranes or other linings are pressed laterally into mutual engagement. The natural springiness of the grass should ensure that the grass at the peripheries of the trays expands or springs slightly laterally, so as to give the so- assembled utility surface the appearance and experience of a continuous surface.

US-A-5467555 discloses a turfing system for stadia wherein there is provided a plurality of growing pans for a transportable turf, activity surface, with each pan comprising side walls whose top edges have integral, outwardly-extending ledges to which respective, segmented fence sections are hingedly connected, whereby the top surface of a plant growing medium is maintained at a level above the side walls. In use of this prior art turfing system, a

plurality of such growing pans can be brought together in side-by-side relationship, to provide a playing surface which is devoid of removable components and which enables adequate drainage of water under the playing surface.

In US-A-5309846, there is described a system for creating a temporary grass playing field, comprising a plurality of pallets containing growing grass and having removable upper side wall edge members which, when removed from the pallet side walls, permit the grass of adjoining pallets to nit together for a prolonged period of, say, ten days, to provide a playing field of the desired shape.

Essentially, each of these three prior art arrangements described above can be summarised as including, inter alia, an element for use in the assembly of a utility or activity surface, which element comprises at least one upstanding side wall and means having an upper region which is at a level above that of the upper edge of said at least one side wall and whose upper surface defines at least part of the utility or activity surface to be assembled from one or more of the elements, said means being contained generally within said at least one side wall.

However, it has been found that the integrity of the "joins" between the grass at the peripheries of the adjacent elements is not always sufficiently good, resulting in undesirable linear gaps in the utility or activity surface which should otherwise be continuous.

Also, wear and tear of the utility or activity surface during use thereof tends to expose such joins between

the grass at the peripheries of adjacent elements.

Summary of Invention The present invention starts from a recognition of these and other disadvantages of the traditional soccer pitch, whilst also recognising the need for more cost effective, more readily manageable and efficient construction and arrangement of such a pitch. Accordingly, the present invention aims to eliminate, or at least substantially reduce, these and other disadvantages of the prior art arrangements discussed above.

Thus, and in accordance with a first aspect of the present invention, the utility surface element is characterised in that said means which is contained generally within said at least one side wall thereof, has a deformable, preferably compressible, peripheral portion of its upper region projecting outwardly beyond the upper edge of said at least one side wall.

Said means may comprise a filling material contained generally within the element which can be generally tray-shaped. In a preferred embodiment of inventive utility surface element, the filling material comprises soil and/or any other suitable growing medium, in which case, the upper surface thereof may be provided with a layer of growing grass which, in certain circumstances, can provide at least part of an activity surface, such as a soccer pitch.

When two or more of the elements are brought together in side-by-side relationship with each other during assembly of a utility surface, to bring

respective upstanding side walls of adjacent elements into confronting, preferably contacting, relationship with each other, the deformable, outwardly projecting, peripheral portions of respective upper surface regions are urged together and deformed, such as compressed, inwardly such that they become generally flush with the upper edges of the upstanding side walls of, say, respective tray-shaped elements. In this manner, secure and unobtrusive joins are formed between the now-compressed peripheral portions of those upper regions, and, as a result, any layer, such as grass, on the upper surface thereof. Those joins are such that their integrity is substantially maintained during use of the so-assembled utility surface, even under extreme and arduous conditions of wear and tear.

In certain circumstances, the compressing peripheral portions of the upper regions of two elements being brought together in side-by-side relationship during assembly of a utility surface, may be deformed upwardly out of the general plane of the utility surface, in which case, those upwardly- deformed peripheral portions may subsequently be urged downwardly back into the general plane of the utility surface by, say, rolling or other suitable means.

The outwardly projecting peripheral portions may be self-supporting. However, suitable support means may be provided. For example, the element may also comprises means arranged to support the deformable outwardly projecting peripheral portion of the upper region. Such support may be provided when the element is in use and/or not in use, but preferably the latter, as will be described in more detail

hereinbelow.

Such support means may comprise a ledge detachably or otherwise movably, such as pivotally, associated with the upper edge of the or each upstanding side wall of the element and may extend at least partially therealong and exterior thereto. In a preferred embodiment, the ledge, or other suitable support means, is provided on the inner face of a member which extends along at least part of the length of the at least side wall and which can be detached from or pivoted away from the or each side wall, so that the ledge no longer supports the outwardly projecting peripheral portion which is then suitably exposed for subsequent compression against the corresponding peripheral portion of an adjacent element when the two elements are brought together in side-by-side relationship with each other and with their respective upstanding side walls in confronting, preferably contacting, relationship.

The element may be mobile, that is to say, provided with suitable means, such as, wheels, runners air cushion or air skate, to facilitate its movement across a support surface, for example, the ground or the floor of a stadium in which a utility surface assembled from a plurality of the elements in side-by- side relationship, can be removably installed.

Also, the element may be provided with legs of adjustable height, to facilitate its being brought into juxtaposition, namely, side-by-side relationship, with another element.

In use of the element in assembling a utility

surface, the ledge supporting the outwardly projecting peripheral portion of the upper region can be detached from or otherwise moved with respect to the element side wall, to expose fully that deformable, outwardly projecting peripheral portion, such that it can be brought into contact with a corresponding peripheral portion of another element and, say, compressed as the two elements are brought finally into side-by-side relationship with each other, as described above, to form a secure, tight and unobtrusive join therebetween.

Although the outwardly projecting peripheral portion of the element can be deformable in some way so that it can be compressed, it may also be at least partially resilient. Thus, and on disassembly of the utility surface, the elements are separated from each other and, as a result, the compressed peripheral portions may recover at least partially to their original, outwardly projecting state with respect to the corresponding upper edges of the upstanding side walls. If such recovery does not take place to a reasonable extent or is not complete, then the surfaces of those portions can may be rolled, or otherwise deformed or treated, in order to effect full recovery thereof.

If support means is provided for the outwardly projecting peripheral portion, then such may be placed in position or may already be in position, for supporting those peripheral portions as they are decompressed at least partially into their original outwardly projecting state with respect to the upper edges of the side walls of the elements.

The invention also provides a method of assembling a utility surface using one or more of the elements as defined above in accordance with the first aspect of the invention, as well as any of the modifications thereof described above.

Thus, a second aspect of the present invention resides in a method of assembling a utility surface, comprising providing two or more mobile elements each having at least one upstanding side wall and an upper region whose surface constitutes part of the utility surface to be assembled and, which is at a level above that of the upper edge of said at least one upstanding side wall, and moving the elements into side-by-side relationship to bring upstanding side walls of adjacent elements into confronting, preferably contacting, relationship with each other, characterised by deforming, such as compressing, laterally together peripheral portions of corresponding upper regions of the elements which project outwardly beyond respective upper side wall edges thereof, preferably such that they are generally flush with their associated upstanding side walls, to form a secure and unobtrusive joint therebetween.

Optionally, the so-formed join can subsequently be urged downwardly, for example, by rolling, to counteract any upward deformation of the outwardly projecting peripheral portions of the upper regions of adjacent elements during lateral compression thereof, to return any so-deformed peripheral portions into the general plane of the utility surface.

Each mobile element may be provided with means for supporting the or each outwardly projecting

peripheral portion of its upper region and may be movable during assembly of the utility surface, to permit corresponding peripheral portions of adjacent elements to be compressed together to form the secure joint therebetween.

As discussed above in relation to the element in accordance with the first aspect of the invention, such supporting means may comprise a ledge which extends at least partially along the upper edge of the or each element side wall exterior thereof and which, when the element is in use, can be removed therefrom.

The invention further provides a utility surface when assembled using a method in accordance with the second aspect of the invention defined above.

Brief Description of the Drawings In order that the various aspects of the invention may be more fully understood, preferred embodiments in accordance therewith will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is an elevational view, in partial cross-section, of part of a first embodiment of an element for use in the assembly of a utility surface to be used as an activity surface, such as, a soccer pitch; Figure 2 is an elevational view of a portion of the element shown in Figure 1, showing various components of the element both individually and in an assembled state;

Figure 3 is an elevational view, in partial cross-section, of part of a second embodiment of an element for use in the assembly of an activity surface, such as, a soccer pitch, assembled from a plurality of such elements; Figures 4 to 8 are respective side elevational views of five steps in the assembly of an activity surface, such as, a soccer pitch, showing one element being brought into juxtaposition with respect to a previously-located and fixed element; Figures 5A to 8A are respective diagrammatic plan views of a guide arrangement between the two elements shown in Figures 4 to 8, in their respective assembly steps; and Figure 9 is a sectional view of part of one element showing detail in the region of a side wall thereof.

Detailed Description of the Embodiments Referring firstly to Figures 1 and 2 of the drawings, a utility surface element 1 is generally tray-shaped and of generally square or rectangular shape, when seen in plan, and comprises four upstanding side walls 2 (only one shown) each having an upper, substantially vertical section 3, an inwardly and downwardly directed section 4 and a lower, substantially vertical section 5, with the vertical section 3 having a free edge section 6 depending downwardly from its juncture with the inwardly and downwardly directed section 4.

The base 11 of the tray-shaped element 1 comprises a supporting under-structure of components 12, 13 to or in which may be mounted hover or wheel means, or any other suitable means, such as skids or skates, for rendering the element 1 mobile, so that it can be moved readily from a storage location into position for use as part of a utility surface.

Within the recess defined by the wall sections 4 and 5 and extending along the length of the side wall 2, are spaced structural webs 14 each arranged at right angles to the side wall 2. These webs 14 provide support for the side wall 2, particularly the section 4 thereof, and are supported by a structural beam 15 which also provides support for the base 11 of the element 1.

Outwardly projecting bars 16 mounted to the beam 15 have, at their outer ends, a rubbing strip 17 which can act as buffers to accept the load of adjacent utility surface elements 1 bumping against each other during their manoeuvring and assembly of the utility surface. These rubbing strips 17 may have locating lugs (not shown) to assist in the correct location of utility surface elements 1 adjacent each other in side-by-side relationship during and after assembly of the utility surface.

The tray-shaped utility surface element 1 is filled with soil 7 and may be provided with a flexible lining (not shown) of a suitable geotextile fabric, for drainage purposes. A layer 8 of grass grows on the upper surface of the filling soil 7 and provides a playing surface for the element 1.

As can be seen from Figure 1 and in accordance with the invention, an upper region 9 of the soil 7 extends upwardly above the upper edge 10 of the upper section 3 of the side wall 2, whilst also projecting outwardly beyond that edge 10.

That upper region 9 which extends upwardly above and projects outwardly from the upper edge 10 of the upper section 3 of the side wall 2, is supported by a ledge 24 provided along an inner face 23 of a generally L-shaped arm 20 of which there is a plurality (only one shown) spaced along the length of the side wall 2. The long limb 21 of each arm 20 lies generally exterior of the side wall 2, when in the position shown in full lines in Figure 1 and in chain- dotted lines in Figure 2.

Each L-shaped arm 20 has its short limb 22 pivoted at 25 to a respective web 14 and includes a locking arm 26 which is pivotally mounted to the long limb 21 of the arm 20 at 27 and has a latching nose 26' cooperable with the downwardly depending section 6 of the side wall 2, as shown in Figure 1. Each locking arm 26 may be spring-urged into its latching position. In this position, the arms 26 retain the arms 21 in their raised positions in which a ledge 24 is in supporting relationship with the underside of the outwardly projecting peripheral portion 9 of the filling soil 7.

In Figure 1, the L-shaped arm 20 is shown in its pivoted-down, lower position in chain-dotted lines, wherein the ledge 24 is no longer in supporting relationship with respect to the outwardly projecting peripheral portion and the arm 20 is accommodated

within the inwardly extending recess defined by the side wall sections 4 and 5 and the structural beam 15, thereby freeing the outwardly projecting peripheral portion 9 for subsequent positioning with respect to the outwardly projecting peripheral portion of an adjacent element 1 during manoeuvring thereof in the assembly of the utility or activity surface.

Buffers 28 are also provided on the L-shaped arms 20, to accept the load of adjacent elements bumping against each other during manoeuvring and assembly of the utility surface.

A flexible plastics lining element 30 is located adjacent the side wall 2 such that it follows the inner profile of the side wall sections 3 to 5, whilst also extending over the upper edge 10 of the side wall section 3. The upper end 31 of that liner 30 extends upwardly in the region of the outwardly projecting peripheral portion 9 of the soil 7, to assist in the support and, also, the containment thereof.

In Figure 3 of the drawings, there are shown two examples of a further embodiment of utility surface element 101, in side-by-side relationship just prior to their being brought together in confronting and contacting relationship with each other to form at least part of an activity surface, such as a soccer pitch.

Each element 101 is similar to the utility surface element 1 described above in relation to Figures 1 and 2 of the drawings, wherein each upstanding side wall 102 comprises an upper, substantially vertical section 103, an inwardly and

downwardly directed section 104 and a lower, substantially vertical section 105.

Each generally tray-shaped element 101 is filled with soil 107 having a layer of grass (not shown) growing on its upper surface. Drainage means, such as aggregate 107' is provided at the base of the tray 101.

An upper region of the filling soil 107 extends above the level of the upper edge 110 of the section 103 of the upstanding side wall 102 and, also, has a peripheral portion 109 which protrudes outwardly and laterally beyond that upper edge 110.

The left hand element 101 in Figure 3 shows that outwardly projecting peripheral portion 109 in its unsupported state, whilst the right hand element 103 shows its outwardly projecting peripheral portion 109 in its supported state, such support being provided by a ledge 124 extending along the length of a plate 120 which, in turn, extends along at least part of the length of each side wall 102.

The function of each supporting plate 120 corresponds with that of the L-shaped arm 20 of the embodiment of utility surface element 1 described above in relation to Figures 1 and 2 of the drawings, except that it is movable between its upper, supporting position, as shown in the right hand element 101 of Figure 3, and its lower position, as shown in the right hand element 101 of that Figure, by means of a parallelogram linkage shown generally at 126.

Each of those linkages 126 comprises a pair of parallel arms 127 each pivoted to the plate 120 at 128 and to a web (not shown), at 129, of each element 101.

Each linkage 126 is loaded by a spring 130 for counter-balancing purposes.

In the right hand element 101, the plate 120 is shown in its upper, supporting position with the spring 130 in a generally relaxed untensioned condition and, in its lower position in dashed lines with the spring 130 in its extended, tensioned condition. This arrangement facilitates the generally vertical movement of the supporting plate 120 between its upper and lower positions, and vice versa.

As in the case of the utility surface element 1 described above in relation to Figures 1 and 2, each utility surface element 101 is rendered mobile by means of a suitable wheeled, hover or other mobility arrangement of a conventional nature.

In use of the utility surface elements 1, 101, the elements can be suitably stored with there respective L-shaped arms 20 and supporting plates 120 in their upper positions, so that the outwardly projecting peripheral portions 9, 109 of the upper regions of the filling soil 7, 107, are supported by the ledges 24, 124.

When an activity surface such as a soccer pitch is required to be assembled in, say, a stadium, the requisite number of elements 1, 101 are moved from their storage positions into the stadium. Prior to their being brought into close side-by-side relationship with each other, the supporting L-shaped

arms 20 or supporting plates 120 are moved from their upper supporting positions to their lower non- supporting positions, to expose the outwardly projecting peripheral portions 9, 109 of the upper regions of the filling soil 7, 107. Then, adjacent elements 1, 101 are brought into close side-by-side relationship with each, such that the corresponding outwardly projecting peripheral portions 9, 109 are in substantial engagement with each other. Adjacent elements 1, 101 are then brought into closer side-by- side relationship with each other, such that they are in confronting relationship, with corresponding upper regions 3, 103 of the side walls 2, 102 in generally contacting relationship with each other. As a consequence of this movement, the outwardly projecting peripheral portions 9, 109 are compressed laterally inwardly, such that they are now flush with the upper edges 10, 110 of their respective side wall 2, 102.

In this manner, secure, tight and unobtrusive joins are provided between the grass-covered activity surfaces of adjacent elements 1, 101.

If, during lateral compression of the outwardly projecting peripheral portions 9, 109, those portions tend to be urged upwardly out of the general plane of the activity surface, then a final rolling or other pressing down of the joins will return those portions 9, 109 back down to the general plane of the activity surface, whilst still retaining the integrity of the joins.

When the activity surface is disassembled, adjacent elements 1, 101 are moved apart and, as a consequence, the compressed outwardly projecting peripheral portions 9, 109 will tend to return, or

attempt to return, to their original condition in which they project outwardly beyond the upper edges 10, 110 of the side walls 2, 102. The L-shaped arms 20 or supporting plates 120, as the case may be, are then moved upwardly into their upper supporting positions, such that the ledges 24, 124 are flush with the upper edges 10, 110 of the side walls 2, 102.

If the previously-compressed outwardly projecting peripheral portions 9, 109 do not recover fully to their original outwardly projecting states, then the upper edge region of the filling soil 7, 107 can be rolled once again, so that the portions 109 project to their fullest extent outwardly of the upper edges 10, 110 of the side walls 2, 102. This rolling or other "decompression" procedure may be carried out either whilst the elements 1, 101 are in the stadium or after they have been removed therefrom to their storage positions.

In their storage positions, the utility surface elements 1, 101 can have their utility surfaces treated and maintained in good condition whilst not in use.

Each of the two utility surface elements indicated generally at 201, in Figures 4 to 8, represents a third embodiment of the invention and is essentially the same as the first embodiment of utility surface element 1 described above in relation to Figures 1 and 2 but with modifications thereto.

Thus, each utility surface element 201 is generally tray-shaped and of generally square or rectangular shape, with each of its four side walls having an upper, substantially vertical section 203.

The base 211 of each tray-shaped element 201 comprises a supporting under-structure of components, indicated generally at 212, to which may be mounted hover means, such as an air skate, wheel means, or any other suitable means, such as skids or skates, for rendering each element 201 mobile, so that it can be moved readily from a storage location into position for use as part of a utility surface.

Mounted to the component - supporting under- structure 212 of each element 201 are buffers 217 for accepting the load of any adjacent utility surface element(s) 201 bumping against it during manoeuvring of the elements 201 and on final assembly of the utility surface. These buffers 217 may, if necessary, have locating lugs (not shown) to assist in the correct location of utility surface elements 201 adjacent each other in side-by-side juxtaposition during and after assembly of the utility surface.

Each tray-shaped utility surface element 201 is again filled with soil 207 and may be provided with a flexible lining (not shown) of a suitable geotextile fabric, for drainage purposes. A layer 208 of grass grows on the upper surface of the filling soil 207 and provides a playing surface for each element 201.

As can be seen from Figures 4 to 8, and in accordance with the invention, an upper peripheral region 209 of the soil 7 extends above and projects outwardly beyond the upper edge 210 of the upper section 203 of each side wall.

That upper peripheral region 209 which extends upwardly above and projects outwardly beyond the upper

edge 210 of the upper section 203 of each side wall 202, is supported temporarily by a ledge 224 extending along an inner face 223 of a generally L-shaped arm 220 of which there is a plurality spaced along the length of each side wall. The longer limb 221 of each arm 220 lies exterior of the side walls of the elements 201 in the upper position of the arms 220 shown in Figure 4, namely, when each element 201 is in storage and, usually, during preliminary manoeuvring of the elements 201, prior to their being brought into juxtaposition with each other. Each longer limb 221 also has a buffer 230 which, in this upper position of the arm 220, is in engagement with the buffer 217 of the corresponding element 201.

Each L-shaped arm 220 has its shorter limb 222 pivotally connected to the under-structure 212, as in the case of the corresponding element 1 of the first embodiment shown in Figures 1 and 2.

In Figures 5 to 8, each L-shaped arm 220 is shown in its pivoted-down, lower position, wherein each ledge 224 is no longer in supporting relationship with respect to the outwardly projecting peripheral portion 209, thereby freeing the outwardly projecting peripheral portion 209 for subsequent positioning with respect to the outwardly projecting peripheral portions of adjacent elements 201 during manoeuvring thereof in the assembly of the utility or activity surface.

The buffers 230 on the L-shaped arms 220 may also be arranged to accept the load of adjacent elements 201 bumping against each other during manoeuvring thereof and assembly of the utility surface, with the

arms 220 in their upper portions, as shown in Figure 4.

A flexible plastics lining element (not shown) may locate adjacent the side walls, to follow the inner profiles thereof, whilst optionally extending above the upper edges 210 of the side walls.

Each utility surface element 201 is provided with a plurality of legs 240, with only one such leg 240 for each element 201 being shown in Figures 4 to 8 and with each leg 240 having, at its lower end, a skid 241 or other type of foot for permitting sliding of the element 201 over the ground G or other support surface, usually for only short distances during the final assembly of the utility surface.

Supported beneath the under-structure 212 of each element 201 is a plurality of hydraulically - or pneumatically-operable rams 250 (only one shown) spaced along a side thereof, as shown in the right hand element 201 in Figures 4 to 8. The confronting side of the left hand element 201 in Figures 4 to 8 is provided with means, indicated generally at 251, with which the ram 250 of the right hand element 201 is engageable, to link the two elements 201 together during assembly of the utility surface, as will be described hereinbelow. Such sliding means 251 may comprise a latch element 252 engageable with a collar 253 on the operating arm 254 of each ram 250.

A Bowden cable linkage 260 is provided on the left hand element 201 for retaining each arm 220 securely in its pivoted-down, lower position, as shown in Figures 5 to 8, although a similar retention

arrangement (not shown) may also be provided for each arm 220 of the right hand element 201.

In Figure 4, the two utility surface elements 201 are shown just prior to their assembly, with respective arms 220 in their pivoted-up, upper positions supporting the peripheral projecting portions 209 of the soil 207 and grass layers 208, as described hereinabove.

In their parked, storage location, the utility surface elements 201 have respective confronting sides engaging each other, thereby occupying the least possible space, with respective pairs of buffers 230 in contact with each other and with their rams 250 retracted.

In Figure 4, however, the left hand element 201 has already been located in its assembled, in-use position upon the ground G which would usually be the floor of a stadium in which the eventually-assembled utility surface would be employed as an activity surface, such as, a soccer pitch.

Air skates (not shown) which can either be engaged detachably with the underside of the under- structure 212 of the elements 201 or be secured permanently thereto, as an integral part of the elements 201, are used to move the elements from their parked, storage location to their point of use prior to assembly.

The right hand element 201 in Figure 4 is shown in an elevated position above the surface of the ground G, supported as such by air skates.

The arrangement of the two elements 201 shown in Figure 5 is similar to that shown in Figure 4, except that the arms 220 have been pivoted downwardly into their lower positions and the elevated right hand element 201 has been brought into closer confronting relationship with respect to the fixed, left hand element 201. In this arrangement, the plurality of rams 250 of the right hand element 201 are still retracted, whilst the Bowden cable link 260 has been connected to each of the pivoted-down arms 220 of the left hand element 201.

In Figure 6, the right hand element 201 has been brought into closer confronting relationship with respect to the fixed, left hand element 201, with the latches 252 lowered into engagement with the collars 253 on the operating arms 254 of the rams 250, with those rams 250 now extended. Also, the edges of the projecting, peripheral portions 209 of the soil 207 and grass 208 are now just in contact with each other but the buffers 217 are spaced slightly apart. Still, the right hand element 201 is elevated above the level of the ground G, by means of the air skates.

The arrangement of the two utility surface elements 201 shown in Figure 7 is similar to that shown in Figure 6, except that the right hand element 201 has been lowered, again using the air skates but by reducing their lifting power, such that the skids 241 of the legs 240 are now in engagement with the surface of the ground G, with the right hand element 201 now supported thereon. As a consequence, the just, contacting edges of the protruding peripheral portions 209 are now at the same level, such that the respective grass layers 208 are flush with each other.

The final assembly step is carried out by retracting partially the rams 250, as shown in Figure 8, such that the skids 241 are slid along the surface of the ground G and the respective side walls 203 and buffers 217 of the two elements 201 are engaged with each other and, as a consequence, the previously- projecting, peripheral portions 209 are compressed, as shown at 209', to provide a secure join between the edges of the utility surface of adjacent elements 201, as well as an assembled utility surface with enhanced continuity and integrity. Thus, the edges of those compressed peripheral portions 209' are flush with the side wall sections 203.

In certain circumstances, the compressing peripheral portions 209 may be deformed upwardly out of the general plane of the so-assembled utility surface during the final assembly step, in which case, those upwardly-deformed peripheral portions 209 may be urged subsequently downwardly back into the general plane of the utility surface by, for example, rolling or other suitable means.

Once the utility surface has been assembled, its grass may be marked out with pitch markings to provide, say, a soccer pitch.

The utility surface elements 201 may be provided with respective, cooperable male and female docking guides, as shown in Figures 5A, 6A, 7A and 8A.

One of the elements 201 is provided with a male docking guide member, as shown at 301 in those four Figures, with its free end 302 having a ramped portion 303. The cooperable female docking guide member is

indicated generally at 401 in Figures 5A, 6A, 7A and 8A.

That female docking guide member 401 has a generally square cross-section with a square central aperture 402 in which the free end 302 of the male guide member 301 is receivable via an entrance 403.

A latching arm 405 has one end connected pivotally to the female guide member 401 at 406, with its other end pivotally connected at 407 to a restraining mechanism indicated generally at 408.

Intermediate the two ends of the latching arm 405 is provided a wheel 409 connected thereto and rotatable about an axis 410.

In Figure 5A, the male and female docking guide members 301, 401 are shown with the two utility surface elements 201 in their positional relationship discussed above in relation to Figure 5, namely, separated. As the right hand element 201 is moved towards the fixed, left hand element 201, the free end 302 of the male guide member 301 enters the central aperture 402 in the female guide member 402 via the entrance 403, such that the wheel 409 engages with the ramped portion 303 of the guide 301, as shown in Figure 6A.

With the arrangement of the two elements 201 shown in Figures 6 and 7, that is to say, with the edges of the projecting peripheral portions 209 just in contact with each other, the free end 302 of the male guide member 301 is located further inside the aperture 402 of the female guide member 401, as shown in Figure 7A. In this position of the male and female

guide members 301, 401, the wheel 409 has reached the end of the ramped portion 303 of the free end 302 of the male guide member 301.

On final assembly of the two utility surface elements 201, as a consequence of retraction of the rams 250, the free end 302 of the male guide member 301 is in its fully engaged position with respect to the female guide member 401, as shown in Figure 8A.

As a consequence, the restraining means 408 is biassed to the left, as a consequence of the clockwise movement of the latching arm 405 about its rotational axis 406, thereby effectively locking the male guide member 301 within the female guide member 401.

This so-called "docking guide" arrangement ensures that adjacent utility surface elements 201 are maintained in proper side-by-side positions with respect to each other during both assembly of the utility surface and thereafter during use of the so- assembled utility surface.

In Figure 9, there is shown an additional or alternative supporting arrangement for the outwardly projecting, upper peripheral portion 209 of the soil 207, particularly when the arm 220 (not shown in this Figure) is in its pivoted down, lower position and before two confronting portions 209 of respective adjacent utility surface elements 201 are compressed together during assembly of the associated utility or activity surface. This supporting arrangement comprises a flexible, permeable, for example, woven, liner, indicated generally at 501, comprising a first, generally horizontal portion 502 at the lower region of the soil 207, a first generally vertical portion

503 extending upwardly against the inner surface of the side wall 203, a second, generally horizontal portion 504 extending over the top edge of the side wall 203 and projecting outwardly thereof against the underside of the outwardly projecting, upper peripheral portion 209 of the soil 207, a second, generally vertical portion 505 extending upwardly against the outer edge of the outwardly projecting portion 209, and a third, generally horizontal portion 506 which is folded inwardly of the soil 207 to extend just below the surface thereof, embedded therein. An extension 507 of that portion 506 is inclined downwardly further into the depth of the soil 207.

Because this liner 501 is permeable, that is to say, it is woven or otherwise perforated or porous, the root network of the grass layer 208 is able to penetrate the portion 506, thus retaining it in position within the soil 207 and reinforcing the supporting function of the liner 501 upon the outwardly projecting peripheral portion 209 of the soil 207.

On compression of two such portions 209 of adjacent elements 201 during assembly of an associated utility surface, the portions 504, 505 of the liner 501 are deformed accordingly and, when the elements 201 are separated upon disassembly of the utility surface, the portions 504, 505 are able to return to their original conditions, as shown in Figure 9.

Further, and when the corresponding arm 220 is pivoted upwardly into its upper portion, its ledge 224 engages the underside of the portion 504, to provide additional support for the outwardly projecting portion 209.

It is to be appreciated that other types of filling for the elements 1, 101, 201 can be used to provide suitable activity or utility surfaces, for example, a synthetic surface, as long as the upper regions of the fillings have peripheral portions which project outwardly of the upper edges of the upstanding side walls of the elements and which can be compressed when adjacent elements and are brought into confronting, and preferably contacting, relationship with each other, to provide the necessary secure and unobtrusive joins therebetween.