Where turf is to be laid, or has recently been laid, it is essential that normal vehicles are prevented from moving over the surface either of the laid turf or the turf substrate as it is critical that these are permitted to retain their profile until the turf planted is established and can handle the weight of vehicles or the like.

In order to allow access but to cause little damage to the turf, there have been proposed devices which minimize loading onto the surface, which devices had a number of closely adjacent low pressure tyres but we have found that these do not provide the low loading required and can cause local compression of the surface.

One particular area of difficulty has been where the substrate is being laid. For example the requirements for golf greens in the US demands a very shallow, 2 inch, layer of sand over a gravel base through which water at the bottom of the profile passes before passing into drains and it has effectively been impossible to lay a layer of this thickness using any conventional apparatus so the layer has normally had to be laid by hand. Whilst this is inconvenient and expensive for golf greens, it is very difficult indeed if a larger area must have a similar profile.

In the production of root zones for the growth of turf using reinforcement, there have been a difficulty in mixing the reinforcement material with the sand or other material to be used.

There are two normal forms of reinforcing material, plastic mesh elements, which are manufactured and sold under the trade mark of "Netlon", and fibre reinforcement.

Particularly with the mesh elements, these are small portions of a synthetic plastic mesh material cut from a web of such material and it will be appreciated that the elements have free edges extending outwardly therefrom.

Normally, these elements are supplied in bales where they are laid on a sheet material and rolled to keep the elements effectively flat and this minimises the interaction between the elements.

However, once the elements are released from the bale, they can entangle one with another unless carefully handled and this has caused difficulties in mixing the elements with sand where it is desired that the elements, as far as possible, do not inter-engage or inter-engage only with a small number of other elements.

Conventionally, the elements have been mixed into sand by adding the elements to a sand pile and then physically mixing by the use of a front end loader or the like.

This has been slow and cumbersome and not fully satisfactory.

We have proposed dropping the elements onto a moving belt on which sand is already located causing the sand element mixture to drop through the air onto an adjacent belt and possibly repeating this process a number of times and, whilst this is an improvement on the previous methods of handling and mixing elements, it is still not optimal.

The main object of the invention is to provide a means whereby work can be carried out on a surface which can suffer damage by normal wheeled vehicles.

A second object is to provide such means which can be used to delivery accurately layers of material on a prepared surface.

It is a further object of the present invention to provide an apparatus for effectively and economically mixing reinforcing elements with sand, which can if required by associated with a device of the type referred to above.

In a first aspect of the invention, we provide a self propelled apparatus for use on surfaces which are to be undisturbed having a chassis, rollers mounted transverse to the chassis having at least one continuous belt located thereabouts, means on the chassis to provide a driving connection with at least one of the rollers whereby the apparatus can be self propelled.

In a particular form of the device, we provide in association with the apparatus a distributor means whereby a controlled layer of a material can be delivered from the apparatus to the surface over which it is travelling.

In a further aspect of the invention, we provide an apparatus to effect mixing of sand and a reinforcing material comprising a hopper adapted to deliver sand, a main conveyor associated with the hopper and onto which the sand is received, a distribution apparatus by which reinforcing material can be placed on the conveyor and a flail at the end of the conveyor into which the sand/reinforcing mixture passes and which causes the mixture to forceably strike a surface effecting mixing of the components.

In a preferred form of such apparatus, we provide two conveyors, a first conveyor which is located under the source of sand or soil and onto which a relatively thick layer of sand or soil is placed and which is located above a second conveyor onto which the sand or soil is delivered and which travels faster than the first conveyor so that a layer of the material of the required thickness is provided before the re-enforcing material is laid on the top thereof.

We may also provide an apparatus to provide a required sand mixture to the conveyor belt at which the reinforcing material is laid which includes a number of hoppers each of which provides a component which can be metered and which feed into a screw conveyor which acts to mix the components and to deliver them to a hopper for delivery to the conveyor.

In order that the invention may be more readily understood we shall describe in relation to the accompanying drawings one example of each embodiment of the invention.

In these drawings: Fig 1 is a side elevation, with some parts broken away, of the apparatus of the invention; Fig 2 is a section along line 2-2 of Fig 1 of the apparatus showing the roller arrangement.

Fig 3 is a longitudinal section of the distrinution device shown in Fig 1; and Fig 4 is a schematic side view of the mixing apparatus; Referring to the apparatus of Figs 1 and 2 of the drawings, we illustrate a transporting device 10 which has a chassis 11 to which there is connected an undercarriage 12. This undercarriage has a pair of rollers 13, 14, which are preferably of two components 13',13" and 14',14" which can rotate one relative to the other and which extend across a substantial part of the width of the device. There may be located between the rollers 13,14 a number of subsidiary rollers 15 which have their axes parallel to those of the primary rollers. These rollers 15 are idler rollers and may also be split.

One or both of the rollers 13, 14, and normally the rear roller 14 is driven by an hydraulic motor 21 located on each side thereof, the power for which motors can be provided by a diesel or petrol engine 20 attached to the rear of the chassis 11.

Fitted about the rollers 13, 14 are a pair of continuous belts 16',16" each of which is associated with the similarly indicated part of the primary rollers and these belts carry the weight of the device. At the same time, they provide a continuous track over which the driven, and the associated idler rollers 15 pass to provide a traction force for the device. The rollers may be mounted to be adjustable to maintain a required tension on the belt and such an adjustment means is shown at 28. The arrangement is such that the loading on the surface is provided over a large area so that the loading on any area is very slight. Indeed, the loading is such that the compressive force by the device on a surface is sufficiently small as to cause effectively no damage to the surface, even if it is uncompacted.

The drives to the hydraulic motors can be such that each motor is controlled by a lever or the like which levers 22 have 3 basic positions, one where the motor drives the roller to move the device forward, one where it drives the roller to move the device rearward and a neutral position.

It is preferred that the levers can take a number of or a variable position on both the forward and reverse drive to vary the speed of the device. Thus, when the device is driven forward, both levers are in the same position, as they are when the device is reversing. When the device is stopped both levers are in the neutral position.

When the device is to be turned, the levers are located in different positions. Where the turn is gentle, which will normally be the case where the device is being used on a newly formed surface, both levers will be driving the belts in the same sense, one driving the associated roller faster than the other. For a sharper turn, one motor can be stopped with the other driving. For very tight turns, the motors could drive their associated rollers in opposite directions.

Mounted on the chassis 11 adjacent the rear thereof is a driver's position which may have associated therewith the necessary controls to operate the motor 20, the levers 22 for the turning mechanism and any attachment which is connected to the device as will be discussed hereunder.

Some other applications to which the apparatus is extremely well suited, it could be used to spread fertiliser or sand over a surface while causing little or no damage to the surface itself and a specific embodiment of this is described in relation to Fig 3.

It could be used to supply material into areas where it is desirable not to cause any damage to the surface and in one particular form, we may provide a hopper on the machine which has an outlet which may include a screw conveyor or the like in a manually operated tube or chute which can be placed into whatever position required before material is delivered therefrom.

The chute or the like may be provided with an outlet which can be controlled to deliver a metered dose of material.

This apparatus can be particularly useful on, say, a race track where it is required to fill divots taken by horses hooves and in which very often sand is used alone, or it could be used with additional seed and/or fertiliser or other materials therein.

It could be preferred that the outlet could be operated in front of the direction of movement of the machine and the machine could act to provide a flat surface on the top of the divot.

It could also be used as a general tool carrier which could take equipment across or along areas where the surface load has to be maintained as low as possible to avoid damage to the surface.

To provide some indication as to the efficiency of the device, the surface loading is of the order of 30 KPa (4 PSI) whereas a low flotation, rubber tyred vehicle normally has a loading of 140 Kpa (20 PSI).

The device is adapted to operate at 2-3 KPH but under road conditions can operate at 7 KPH.

In the form of device illustrated in Figs 1 and 3 there is a hopper 30 which can receive any required material, such as a sand/reinforcement mix and the arrangement may have associated therewith various output devices, depending on the application. Specifically there may be a delivery conveyor, not illustrated, whereby the contents of the hopper can be delivered to some other apparatus. For example, where we are laying a sand or sand reinforcement mix onto a surface by another machine, which we know as a PaveAyr (trade mark), the hopper of this machine has to be continually refilled with the material being laid and the apparatus of the invention can be used to supply this material without damaging the surface adjacent the PaveAyr. In order to facilitate this, the hopper 30 may be mounted on a turntable 35, so that it can side deliver.

In other applications we use the flat upper surface of the device to carry SquAyrs (trade mark) which are slabs of turf with the root zone associated with the turf and the device may have a hoist and a grab assembly to enable the SquAyrs to be located thereon and delivered therefrom as the required positions. These SquAyrs are heavy and so it is essential when they are being carried over an uncompacted surface that no damage to the surface occurs. At the same time, they have to be accurately located on the surface. We may provide on the device a grab arrangement whereby individual SquAyrs can be taken from the device and delivered accurately into required position In each case it is critical that the loading on the surface be as generalised and as light as possible.

Where, say, a sand based playing field is to be established, it is normal that there be a drainage layer of gravel or stones and beneath which there may be drainage trenches, and over the top of which, there is laid a sand layer which provides the base for the root zone which sand layer is laid and compressed. Over this, again, there is laid a further layer which is a sand/reinforcing material mixture which will ultimately comprise the root zone and on top of this, there is laid or planted turf.

This may be in the form of SquAyrs, as previously mentioned, a washed turf which is laid over the root zone and may have further sand placed on the upper surface thereof which turf will grow into the root zone or, alternatively, although less likely, seeds or stolons could be planted in the root zone layer and turf established in that way.

It is desirable that there be as little disturbance as possible of both the sand layer and the root zone layer. The sand layer, in fact, is normally provided with a predetermined slope is very accurately formed, and it is required that the root zone layer follow the same contour so that the final surface area is as required.

Any localised disturbance of the surface of the layers can either be reflected in the upper surface of the area when completed or, where this is of the sand layer, could provide differential water tables and possible difficulties in maintaining a good surface.

In the embodiment of the invention illustrated in Figures 1 and 3 we provide an arrangement whereby material can be delivered from the device to the ground therebeneath.

In this arrangement, the hopper 30 has a conveyor belt 32 extending along its floor which conveyor belt 32 carries material, which may be sand, matrix material or gravel forwardly to a delivery hopper 41 which may have an auger 42 extending across the width thereof to ensure even spreading of the material and at the lower end of which hopper 41 there is a delivery roller 43 which is driven at a speed which is dependent on the speed along the ground of the device. This roller may be provided with a ribbed or otherwise formed surface to assist in accurate delivery. A shutter 44 is associated with this roller so that, depending on the speed of the device and the position of the shutter the rate of delivery of the material can be accurately controlled.

Mounted forwardly of the roller 43 is a rotary bristle brush roller 45 which ensures that the material on the roller 43 is all delivered to the adjacent surface.

The arrangement is such that if, say, sand is being delivered from the device a very thin, accurate layer of material can be delivered. It is possible to provide a consistent layer of as little as 5 mm can be provided.

It will be appreciated that when the material has been delivered, it almost immediately passes under the belts 16 and this, although it provides a minimum loading it ensures that the material delivered is retained as it was laid.

Whilst the device is particularly useful for the accurate delivery of sand, it is to be appreciated that it is also very useful where screenings or soil have to be delivered. In these cases, the thickness of cover will generally be greater, but the delivery is sufficiently controlled to ensure accurate and even delivery.

The hopper 41 may have an extension or pair of extensions 46 whereby the hopper can be located over a circular member 47 on the chassis. An hydraulic ram 48 associated with the hopper 30 is connected at one end to hopper 41 to locate the distribution device in position. The distribution device may be disconnected by extending the hydraulic ram 48 causing the extensions 46 from disconnecting with the the member 47 and then releasing the ram 48. This ram can be used for other applications such as control of the delivery conveyor mentioned earlier.

Referring now to Fig 4 we illustrate a device which is adapted to mix reinforcing material with sand or a matrix (which can be a mixture which includes sand, soil, peat moss and possibly other components). For the purpose of the description, we shall refer generally to sand unless there is reason to differentiate the material.

In the illustrated embodiment we have an elongated frame 50 which frame has a conveyor 51 running a substantial part of the length thereof.

Adjacent one end of the conveyor, there is a hopper 52 which is adapted to receive the sand.

This sand is adapted to provide the root zone on which turf is to be grown and through which the root system of the turf is to pass.

This hopper is provided with an adjustable outlet means which comprises conveyor 53 which may deliver sand at a required depth, in practice of the order of 200 to 300 mm and there is a rotary brush 54 which ensures that all the sand is delivered to the conveyor 51. We may provide a shutter 55 at the forward end of the hopper 52 so that the quantity of sand which is passed onto the conveyor 51 can be varied so that variations of the outlet size and the speed of conveyor 53 can control the movement of sand therefrom.

The speed of conveyor 51 can be of the order of 10 times the speed of conveyor 53 so that the thickness of the sand layer on the conveyor 51 can be of the order of 20mm.

Further along the conveyor 51, there is provided means to distribute reinforcing material onto the surface of the sand on the conveyor.

Depending on the type of reinforcing material this can vary.

In a first form, the reinforcing material is in the form of Netlon mesh elements which are delivered in bales which are formed by rolling a web of synthetic plastic material onto which elements are fed when being formed so that as the bale is unrolled, elements are freed.

In the particular arrangement we may have a first distributor 60 having an upward delivery position 61 at which a bale is located. The arrangement being such that the web material from the bale can move forwardly and downwardly, on the downward movement the reinforcing material 62 drops onto the conveyor 51 which is there below, and then rearwardly to a take up means 63 whereby the web can be gathered for later destruction.

The take up position 63 may be provided with an hydraulic motor 64 or the like whereby the speed of rotation can be varied so that the quantity of mesh material delivered onto the surface of the sand can be varied.

A second delivery position 65 can be considered identical to the position 60, and is spaced along the conveyor therefrom and this arrangement permits continuous delivery of the Netlon elements. The elements are first delivered from one position and when the bale is depleted, the elements are fed from the other position whilst the first bale is replaced and so on..

Of course, the hopper 52 can continually be refilled and in this way the machine can be used to maximum effect.

In the second application of this embodiment, the reinforcing material may again be elements but may be provided, initially in the form of a broad loom roll approximately of the same width as the conveyor, the arrangement being such that as the roll leaves the delivery reel, it can initially be cut into strips longitudinally and as it passes over an edge cut transverse into elements which are effectively identical to those which would come from a bale and drop onto the conveyor.

In order to effectively do this cutting, we may prefer to ensure that we keep a positive pressure in a chamber through which the web passes to ensure that the cutting knives are not blunted by any sand or foreign material which may be passing therethrough.

One particular manner of cutting the re-enforcing material is to provide a pair of rollers, one of which has a number of recesses therein which define the shape of the required elements and the other has blades which are complementary to these, the two rollers meshing so that the blades enter the recesses and act to cut the re-enforcing material which passes therebetween into the required shapes.

In the third aspect, which may be more suitable for fibre reinforcement, the reinforcing material may be fed into a hopper and the hopper may either have means whereby the material can fall there from under gravity or may have delivery means therein to, once again, place the material onto the surface of the sand on the conveyor.

At the forward end of the conveyor 51, there is a flail 70 which may comprise a central axis 71 having a number of, preferably four, blades 72 extending along its length, the blades being of a flexible material such as a rubber coated fabric or the like.

This flail is connected to a source of power which can be a chain drive 73 from the conveyor and can rotate at a relatively high speed.

The arrangement is such that mounted forwardly of the flail there is a wall 74, which in one form is comprised of three members connected horizontally and at an angle to each other so as to present an angled face towards the flail and the material from the flail is thrown forwardly, hits the wall and then drops either to a position from which it can be moved or alternatively onto a conveyor by which it can be moved.

We have found that this basically, rather simple operation causes extremely good mixing of the reinforcing material with the sand and the sand/reinforcing material mixture so formed is ready for use without further operations.

If it was believed that further mixing was beneficial in particular cases, then there would be no reason why the material could not be either re-circulated through the flail or alternatively passed through a further mixing station which may comprise a flail or some other form of mixing.

In a still further variation, we may require to use a sand mixture, typically sand, peat moss and fertilizer. In order to pre-mix these and pass them to the delivery hopper, we can provide 3 hoppers each of which has one of the components. If required, a preliminary treatment can be effected in or associated with the hoppers. For example, peat moss could be commutated in a hopper so that small particles can be delivered from the hopper.

Each of these hoppers deliver at a metered rate to a screw conveyor which serves two purposes.

One of these is that it delivers the mixture from the hoppers to the hopper of the machine in which the re-enforcing material is delivered. The second is that during delivery, the components can be thoroughly mixed.

Thus, the individual components can effectively be mixed before they reach the machine at which the re-enforcement is added.