GB2561420A - Process for producing turf pieces and a turf harvesting machine - Google Patents

Abstract

A process is disclosed for the production of turf pieces having a desired length and capable of being laid in abutting relationship with one another to form a grass lawn. The process comprises harvesting from a field a strip of turf having a length significantly greater than the desired length of the turf pieces, coiling the strip into a roll in the field and, while coiling, inserting between the coils of the roll a web of a sheet material having high tensile strength to separate the soil side of each coil from the grass side of the adjacent coil, tension in the web being increased during coiling, transporting the roll from the field to a processing plant, and, at the processing plant, uncoiling and cutting the strip into individual turf pieces of the desired length. Also disclosed is a turf harvesting machine for harvesting a coiled strip of turf 16 having a web 52 separating subsequent coils and a tensioning device for increasing the web tension during coiling of the strip.

Description

(54) Title of the Invention: Process for producing turf pieces and a turf harvesting machine Abstract Title: Process for producing turf pieces and a turf harvesting machine (57) A process is disclosed for the production of turf pieces having a desired length and capable of being laid in abutting relationship with one another to form a grass lawn. The process comprises harvesting from a field a strip of turf having a length significantly greater than the desired length of the turf pieces, coiling the strip into a roll in the field and, while coiling, inserting between the coils of the roll a web of a sheet material having high tensile strength to separate the soil side of each coil from the grass side of the adjacent coil, tension in the web being increased during coiling, transporting the roll from the field to a processing plant, and, at the processing plant, uncoiling and cutting the strip into individual turf pieces of the desired length. Also disclosed is a turf harvesting machine for harvesting a coiled strip of turf 16 having a web 52 separating subsequent coils and a tensioning device for increasing the web tension during coiling of the strip.

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Pack and/or palletise processed turf pieces

- 1 PROCESS FOR PRODUCING TURF PIECES AND A TURF HARVESTING MACHINE

The present invention relates to the production of turf pieces for laying grass lawns.

BACKGROUND

Lawns can be produced by sowing grass seeds but they take a long time to grow. In some warmer regions of the world, it is possible to grow a lawn by scattering sprigs of grass, sometimes also called plugs, instead of seeds. Though faster than sowing seeds, this method still requires a relatively long period of time for the sprigs to grow roots into the earth and for them to propagate laterally to form a uniform lawn. The fastest method of producing a lawn, and to which the present invention relates, is to lay pre-grown turf pieces.

It is important to distinguish between turf pieces and sprigs. Turf pieces are produced by growing grass, which may be a mixture of different species of grass, in a field and harvesting the turf by horizontally cutting the ground under the grass to a uniform depth. The shaved off thin layer of the ground, which comprises the grass, at least part of the root system and some of the soil which is held together by the root system, is cut into turf pieces, usually rectangles, having an area of typically 1sq.m, which are laid on previously prepared ground in the same way as tiles. It takes a relatively short time for the roots of the grass of the turf to grow into the soil of the ground and for the pieces of turf to grow and mesh into one another so as to close any gaps between them. As a result a complete manicured lawn can be created in a matter of days. The turf pieces are butted together tightly and new grass only needs to grow to fill in the small cracks between the individual turf pieces.

-2The essential point to note is that, in the case of a lawn made from turf pieces, most of the grass will have been laid, whereas in a lawn grown from sprigs most of the grass will have grown in situ. This accounts for the difference in time required for the lawn to reach full maturity.

Because of the difference between sprigs and turf pieces, the methods by which they are produced are totally different. To produce sprigs, turf pieces may first be harvested as described above and then broken up into small sprigs. It has been proposed in US 4,063,385 to harvest a strip of turf and to transport it to a processing plant, where the strip is washed before excess soil and moisture are removed to leave a grass mesh with exposed roots. The mesh is scored to define small sprigs which can be broken away from this grass mesh and scattered over prepared soil. The sprigs are packaged in absorbent trays and moisture held in the trays is gradually given back to the living grass during shipment.

Unlike sprigs, turf pieces are large heavy and bulky items that are normally packaged on pallets in the field.

After they have been harvested, the turf pieces are stacked, commonly by the harvesting machine, on a pallet. The palletised turf pieces can either be flat or, in some cases, coiled into rolls. After a set of rolls has been amassed, typically comprising ten turf pieces, they are picked up by a stacker and placed onto a pallet. A number of sets are then stacked one above the other, each set of rolls being rotated through 90° about a vertical axis relative to the next lower set. Once a pallet has reached a desired height it is discharged from the harvesting machine and a new pallet is commenced.

Sprigs and turf pieces present very different problems in their packaging, transportation and shipment. As previously mentioned, sprigs are packaged in open trays that retain moisture and they can continue to grow from the time of their

-3 cultivation until they reach the end user. As they have access to both oxygen and light when in storage, the shelf life of sprigs is not of major concern.

By contrast, turf pieces start to decay the moment that they are coiled or stacked. The grass continues to breath and to give off carbon dioxide which then builds up in the pallet, be it between the coils of a roll or between the individual turf pieces in a stack. This is accompanied by a rise in temperature, which can reach values as great as 70°C at the centre of a stack. Because grass can only survive for a short time under such conditions, the shelf life of harvested turf pieces is quite short. For this reason, the entire production process for turf pieces is designed to minimise the time from harvesting to palletising and shipment and with, this in mind, harvesting is performed on demand regardless of the prevailing weather conditions and may often even take place at night.

Using a harvesting machine to harvest the turf, then to stack the turf pieces on pallets, has obvious efficiency advantages and is therefore the frequently adopted method in the turf growing industry. It is also known, though less efficient, for a harvesting machine to leave turf pieces on the ground for them to be picked up and palletised manually or using a separate machine.

SUMMARY

According to the one aspect of the present invention, there is provided a process for the production of turf pieces having a desired length and capable of being laid in abutting relationship with one another to form a grass lawn, which process comprises:

harvesting from a field a strip of turf having a length significantly greater than the desired length of the turf pieces, .

-4coiling the strip into a roll in the field and, while coiling, inserting between the coils of the roll a web of a sheet material having high tensile strength to separate the soil side of each coil from the grass side of the adjacent coil, tension in the web being increased during coiling, transporting the roll from the field to a processing plant, and at the processing plant, uncoiling and cutting the strip into individual turf pieces of the desired length.

The tension in the web needs to be low at the commencement of coiling of a roll, in order to permit the web to be entrained with the turf. Once the web is securely entrapped between the initial coils of the roll, the tension is increased either gradually as the diameter of the roll increases, or in one or more step changes, so that the outer coils of the roll are more tightly bound by the web.

The high tensile strength of the web is essential to add structural integrity to the roll by being able to add significant tension to the web whilst rolling. Without such high tensile strength, the web would break under tension. Also due to the size and weight of the roll, high forces are applied to the roll / web as it is handled again needing a high tensile strength to avoid breaking.

To commence a roll, the strip of turf may either be coiled onto itself or around a cylindrical core. If coiled on itself, the weight of the roll is supported during transportation entirely by engaging the outer surface of the roll, the tensioned web permitting this to take place without the roll collapsing. If coiled around a core, the roll may be used to support some or all of the weight, but the web is still needed to prevent collapse of the roll.

All of the processing of harvested turf to produce turf pieces, as opposed to sprigs, whether carried out using a

-5 single harvesting machine or using separate machines for harvesting and palletising, has hitherto been carried out in the field. By processing the harvested strip under controlled conditions in the processing plant, the invention enables the quality of the palletised turf to be monitored and improved.

The size of the strip from which sprigs are produced need not be large and will typically not exceed 20m. Such a strip can readily be coiled into a roll around a tube, or core, and transported. A machine capable of harvesting a strip of turf and coiling it in this manner is disclosed for example in CA 2399352, which also contemplates winding a fine mesh or web between the coils of the roll. The central core can be engaged by a lifting arm on a fork lift truck to transport the roll.

By contrast, for the process of the present invention to be economically viable, the length of the strip that needs to be harvested to produce turf pieces needs to be significantly greater, being typically well in excess of 100m in length. Coiling and transporting a strip of such length cannot be achieved by the methods taught in the prior art. Even with the use of a core at the commencement of a roll, the resulting roll would not be transportable. Attempts to raise such a large roll either using the core or by engaging its outer surface could result in collapse of the roll and/or in serious damage to the turf.

In the present invention, the integrity of the coiled roll is derived, not from the turf itself nor from a core about which it is coiled, but from the web wound between the coils. Even with the strip coiled only on itself, avoiding the need for a core, the tensioned web results in a tightly bound bundle that has sufficient structural integrity to be lifted by engaging its outer surface, such as by means of a fork lift truck.

-6The web proposed in the prior art, for example in CA 2399352, is intended only as a wrapping around a completed roll and is not one intertwined with the coils of the roll to provide structural strength. Furthermore, the suggested materials of the web, namely a mesh or polythene, have too little tensile strength to give a large roll the necessary structural integrity to enable it to be lifted by a fork or a clamp engaging its outer surface.

While the use of the same harvesting machine to shave turf from the ground, to cut the turf into pieces, to roll or stack the pieces and then to palletise them, minimises the time from harvesting to re-laying of the turf pieces, the present inventors have recognised that this conventional method of production adversely affects the quality of the finished product, that is to say the rolled (or stacked) and palletised turf pieces. A primary factor affecting the quality is that processing of the turf has to be carried out in the open. The conditions can therefore be wet, cold and windy. Furthermore, harvesting may sometimes need to be carried out in the dark. Even under ideal harvesting conditions, some turf pieces produced by the harvesting machine can be of substandard quality, and these need to be identified by the operator and prevented from being palletised.

There are various reasons for the occurrence of such substandard turf pieces. A first reason is that weeds or undesirable weed grasses may be present which are difficult to see in the field. A second reason is that the harvesting machine may cause damage to the turf as it is being harvested as a result of the condition of certain areas of the field or by improper operation of the harvesting machine. For example, if the speed of the harvesting machine is not correctly matched to the cutting speed, the turf pieces may tend to fall apart by being over-stretched especially in an area of the field where the turf is weaker. Clearly, when operating in the

-7dark or in poor weather conditions, the operator is unlikely to reject all sub-standard turf pieces.

In the present invention, only the harvesting of the turf is carried out in the field. The harvesting machine makes no attempt to cut or palletise turf pieces and the operator is primarily called upon only to keep driving the harvesting machine in a straight line. After a harvested strip has attained the required length, the operator needs only to lower it onto the ground and prepare the harvesting machine to commence harvesting of a new strip. Each strip shaved from the ground (there are usually two as the ground may not be perfectly flat) is rolled into a single large roll, which may be seventy, eighty, ninety, a hundred or more times the length of the turf pieces to be cut from it. As long as the shaved strip is being added to the roll, the harvesting machine operator does not need to concern himself with turf quality and the entire operation can therefore be carried out from the cab of harvesting machine, where it is warm and dry. Lighting at night is only required constantly to give the operator a clear view of the ground in front of and around the harvesting machine .

After transportation to the processing plant, the harvested turf is uncoiled and may now be viewed and analysed under controlled ambient conditions before it is cut and palletised. Weather will not affect the operating conditions in the processing plant and as much light as is necessary can be provided to facilitate identification of sub-standard regions of each harvested turf strip, to prevent them from finding their way into the end product.

The action of uncoiling the large roll at the processing plant allows harmful respiration gases (CO2) and heat to escape, which is of benefit.

-8An important advantage of analysing the turf in a processing plant is that many operations may be automated. For example, the analysis of the turf quality can be carried out using cameras and suitable image analysis software, making quality control less subjective. Such techniques would be difficult to implement on board a harvesting machine because of the adverse operating conditions; for example, camera lenses would be constantly coated with cutting debris or mud.

Automated detection of sub-standard regions also enables wastage to be minimised in that only those regions that need to be rejected are discarded instead of having to reject a complete turf piece because it contains a small defect such as a hole or a bald patch.

In order to implement the process of the invention, it is necessary to handle a rolled up strip of turf that may have a length of typically around 130m, the roll having a diameter of about 2m.

A problem that may occur when forming a strip of such great length into a roll is that if the operator drives through an area of damaged turf and the turf breaks apart for any reason, it would fall back on itself as it is added to the roll that is being formed, and prevent the harvester continuing. Another problem is that even the harvested strip is of turf of good quality, it can fall apart when discharged from the harvesting machine, or when an attempt is made to transport it using a fork lift truck.

These problems are all mitigated in the present invention on account of the fact that the harvesting machine inserts between the coils of the roll a web of a sheet material having high tensile strength separating the black, or soil, side of each coil from the green, or grass, side of the adjacent coil.

-9Preferably further layers of the web may be wrapped around a completed roll to protect the outermost coil on the roll. When wrapped in this manner, a roll can be picked up using a forklift truck without causing damage to the outermost coil of the roll.

It is desirable that the web should not be an open mesh, but that its surface should be continuous. This ensures that the web cannot become entangled with soil and it also prevents the forks of a forklift truck, or a clamp designed to engage the outer surface of a rolled strip, from making direct contact with the outer coil of the roll.

While it would be possible to use a material, such a woven polypropylene fabric, it is preferred for lightness to use TYVEK®, or a plasticised fibre-reinforced paper.

The web may furthermore comprise different materials. For example the start, middle and end could be of different materials that are welded or stitched together. Heavier material may be used at the end of the web to add extra support to the outside of the formed roll, and it the end material can also be chosen to be more 'robust' material, to withstand handling.

The web may be made of a material that is highly wearresistant and virtually tear-proof, permitting it to be recycled without incurring any significant damage.

The web may be separated from the turf strip in the processing plant and coiled back into a roll which it returned to the harvesting machine to be wrapped around a fresh strip of turf.

An important advantage offered by the invention is that the harvesting can be carried out rapidly, and on arrival at the processing plant it will be cooled down when uncoiled. Any decay of the turf need not therefore commence until after the

- 10turf has been processed in the processing plant, and steps can be taken during the processing of the turf to minimise decay during shipment. In this respect, the processing plant may control the atmospheric conditions at the station where the turf pieces are being rolled, to minimise carbon dioxide content and thereby increase shelf life. The turf pieces may further be refrigerated before or after they are packaged for transportation to the end user.

A further advantage offered by the invention, is that, in the processing plant, the turf may be mowed under controlled condition and debris from its surface removed by suction before it is cut and coiled into smaller turf pieces for palletising and distribution. The mowing and vacuum cleaning after mowing avoids composting of the cuttings taking place in the palletised turf pieces.

The processing of the turf in a processing plant converts turf production from an essentially agricultural process to a manufacturing process where a variety of further steps may be performed before the final packaging of the turf pieces.

Other processing steps that may be carried out in the processing plant, include spraying the turf with different solutions, for added benefit and removing excess moisture to reduce transportation costs and improve the ease of handling, when laying a lawn.

A primary advantage of the invention resides in the ability to improve quality control by constant automated monitoring of the turf production process. As well as minimising the occurrence of sub-standard turf pieces, the process can be used to improve uniformity which can also improve the palletising, allowing it to be more regular.

The processing of the turf in a plant further allows the retention of data on each batch of turf produced. Indeed, it would be possible to identify each turf piece using an

- 11 inexpensive RFID tag and to photograph and maintain a record of each turf piece during production.

Furthermore the palletising may be improved as the pallets can be wrapped in film and each pallet may carry a printed label containing information as to its date and place of production traced as well as recommendations for laying of the turf and information on the species of grass that it contains .

In accordance with a second aspect of the invention, there is provided a turf harvesting machine comprising a vehicle having a cutting head for shaving a strip of turf from the ground, an elevating conveyor for raising the shaved strip from the level of the ground, a coiling station at which the strip transported by the elevating conveyor is coiled into a roll, and a web supply for feeding into the coiling station, under tension, a web of a sheet material having high tensile strength to be wound between the coils of the turf strip so as to separate the black soil side of each coil of turf from the green grass side of the adjacent coil and bind the coiled turf into a roll, the web supply comprising a tensioning device for increasing the web tension during coiling of the strip.

The vehicle may either be self-propelled or designed to be towed by a tractor.

In an embodiment of the machine, the coiling station the turf is coiled on itself to produce a coreless roll.

In view of the size of the completed roll, it risks being damaged if dropped onto the ground from any significant height. In an embodiment of the invention, such risk is avoided by the entire coiling station being displaceable relative to the elevating conveyor to enable a completed roll to be lowered substantially to ground level prior to being discharged from the harvesting machine.

- 12In some embodiments, the coiling station may comprise two mutually inclined conveyors and the relative angle of inclination of the two conveyors may be increased as the size the roll of turf that is being formed increases.

The mutual inclination of the coiling station conveyors may be controlled either in dependence of the measured length of strip fed into to the coiling station or in dependence upon the detected size of the diameter of the roll being formed.

In order to avoid tearing or buckling of the shaved strip, it is desirable for the speed of the elevating conveyor and of the conveyors of the coiling station to be set automatically in dependence upon the measured ground speed of the harvesting machine.

Turf tends to stretch slightly as it is being harvested and it is desirable for the speed of the conveyor to exceed the ground speed of the harvesting machines by a factor, preferably adjustable by the operator of the machine, to compensate for the stretching.

During operation, if the elevating conveyor is operating faster than the coiling conveyors, a ripple will tend to form upstream of the roll. If the coiling conveyors are too slow, this ripple may grow to a point of collapsing on itself and create an undesirable fold in the coiled strip. Operation of the coiling conveyors at too high a speed, on the other hand, will reduce the height of the ripple and may result in tearing of the turf strip.

In some embodiments of the invention, a sensor is provided to determine the height of a ripple in the turf upstream of the coiling conveyors, the sensor output serving to control the speed of the coiling conveyors so as to maintain the ripple at a desired height.

- 13 As has been mentioned earlier, because of possible unevenness in the ground, two strips of turf are commonly harvested side by side using separate cutters and they are coiled at the same time. If the cutters are set at different depths and the resulting strips are of different thickness, rolls having strips of the same length will have different diameters. As the same coiling conveyors are being used to form both rolls, the angle between conveyors cannot be set correctly for both sides at the same time. If the strips are being wound around a common core, the resulting rolls would be asymmetrical.

To mitigate this problem, embodiments of the invention may include sensors to determine the thickness of the harvested turf strips and to control the depth of the cutters to ensure that the rolls grow in diameter at the same rate.

The sensors may sense the thickness of the two turf strips directly, or they may sense the diameters of the two rolls.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram showing the essential components of a harvesting machine of the invention,

Figure 2 shows the harvesting machine of Figure 1 in an alternative position,

Figure 3 shows the harvesting machine shown in Figure 2, in a further alternative position, and

Figure 4 is a flow chart showing the steps involved in carrying out the process of a preferred embodiment of the invention.

- 14DETAILED DESCRIPTION OF THE DRAWINGS

Figures 1 to 3 of the drawings illustrate schematically the operation of a turf harvesting machine designed to harvest a long strip of turf. More usually two such strips at the same time disposed side by side are harvested at the same time and each is coiled into a respective single large roll. The length of each strip is typically in the region of one hundred and thirty metres, which is very significantly longer (by a factor of around one hundred) than the length of the turf pieces one normally butts together to form a lawn.

The parts of the harvesting machine 10 shown in Figure 1 may be mounted on a trailer that is towed by a tractor but are preferably part of self-propelled vehicle. The vehicle cab and drive train may be similar to a conventional turf harvesting machine and are therefore not shown in the drawing and are not described herein in detail.

As the harvesting machine moves from right to left in Figure 1, a knife 12 maintained at a preset depth beneath the ground by a roller 14 is oscillated from side to side to slice through the soil beneath the grass and separate a strip of turf, designated 16 in Figure 1. The turf 16 is raised by a driven elevating conveyor 18 onto an inclined driven conveyor 20 towards a roll forming conveyor 22 which will be described in more detail by reference to Figures 2 and 3.

The roll forming conveyor 22 starts in the position, and near vertical attitude, shown in Figure 1. As the leading edge of the strip 16 of turf collides with the conveyor 22, it is driven upwards and ultimately falls back on itself, as shown in Figure 1, and commences to form a roll. In an alternative embodiment of the invention, not shown in the drawings, the leading edge of the harvested strip 16 may be wrapped around a central support core placed at the junction between the conveyors 20 and 22.

- 15 Figures 2 and 3 show the conveyor 20 mounted on a rocking frame 26 that is pivotable relative to the main frame 24 of the harvesting machine about an axle 28. One end of the roll forming conveyor 22 is mounted on the rocking frame 26 and is pivotable about an axle 30 relative to the rocking frame 26. A first hydraulic cylinder 32 is used to pivot the roll forming conveyor 22 about the axle 30 and a second hydraulic cylinder 34 is used to pivot the rocking frame 26 about the axle 28.

At the start of harvesting a strip 16, the rocking frame 26 adopts the near vertical attitude shown in Figure 1. As the length of the harvested strip 16 increases, the diameter of the roll that is formed by coiling the strip increases. The size of the roll is sensed by a sensor 40 mounted on the rocking frame 26. The sensor 40 controls the hydraulic cylinder 32 to cause the roll forming conveyor 22 to pivot clockwise, as viewed, towards the position shown in Figure 2, thereby increasing the angle between the two conveyors 20 and 22 to accommodate the increasing diameter of the rolled strip.

When the roll reaches its desired size, the turf strip is cut and all three conveyors 18, 20 and 22 continue to operate. The operator then issues a control signal to the hydraulic cylinder 34 which tilts the rocking frame 26, and with it both of the conveyors 20 and 22 to the position shown in Figure 3 to enable the completed roll to be lowered gently onto the ground. As the roll forming conveyor 22 may be nearly horizontal when a roll is being discharged, it may not be sufficient to rely on the action of gravity for the lowering of the completed roll onto the ground. For this reason, when a new roll is completed and the rocking frame is tilted to lower conveyor 22 to the ground, the roll does not simply roll down the conveyor 22 and instead the conveyor is powered to deposit the roll on the ground.

- 16If turf were to be rolled into a large roll without any additional steps being taken, harvesting would need to be stopped if the strip of turf breaks for any reason. Furthermore, the roll of turf risks falling apart while being raised from the ground and transported. To avoid this problem, the harvesting machine carries a roll 50 of a web 52 having high tensile strength, Tyvek®, tarpaulin or a polypropylene fabric being possible materials, which web 52 is fed onto the conveyor 20 and is coiled together with the strip 16 of turf.

The web 52 has a leader (not shown) with a metal pole that is used to thread the web 52 onto the conveyor 20 ahead of the leading edge of the strip of turf to be coiled. If a central core is used, the leading edge of the web may be secured to the core to assist in wrapping the harvested strip around the core. At the commencement of the formation of a new roll, the web 52 can be drawn freely from the roll 50 the result in its leading edge being firmly secured between the initial coils of the turf roll. Thereafter, the web 52 is tensioned by friction braking of the roll 50 so that the web acts to bind the coils of the roll firmly. When the web 52 approached its end, the turf strip is cut to separate it from the ground but rotation of the conveyors 20 and 22 is continued until the entire strip has been coiled and the end of the 52 has been wrapped around the completed roll. Only when a roll of turf has been enveloped in the web 52 in this manner, does the operator activate the cylinder 34 to tilt the frame 26 into the discharge position shown in Figure 3 where rotation of the conveyor 22 will lower the completed roll to substantially ground level before it is discharged from the harvesting machine.

To avoid the strip 16 of turf from tearing or buckling, it is desirable to match the speed of the conveyors to the ground speed of the harvesting machine and to allow for the stretching of the turf that tends to occur naturally.

Hitherto, this has been done by eye but it is preferred for

- 17the conveyors 18, 20 and 22 to be driven by variable speed motors controlled by a sensor producing a signal indicative of ground speed. The operator may set the ratio of the two speeds to ensure that the degree of stretch is compensated for by the conveyors as the turf is being harvested.

The harvesting machine as described above does not require the quality of the harvested turf to be monitored as it is being harvested. All the operator has to do is drive and steer the machine until a desired length of turf has been harvested. In some embodiments, the machine may not even be steered by the operator but steered by GPS, for example.

Once a strip of the desired length has been harvested, the operator brings the harvesting machine to a stop and the conveyors 18, 20 and 22 continue to operate for a short time while the harvesting machine remains stationary. This causes the ends of the strip to be torn from the ground and ensures that the whole of the strip is wound on the roll and wrapped in the web 52. The conveyors 18 and 20 and 22 are then stopped and the rocking frame pivoted towards the position in Figure

3. Finally, the conveyor 22 is driven to lower the roll onto the ground and a fresh roll 50 of web 52 is mounted on the machine and threaded onto the conveyor 20 to commence harvesting of the next strip.

All the operations described above can be carried out by one operator, even when working at night and under adverse weather conditions. This considerably simplifies and speeds up the harvesting process, which in turn results in a reduction of the time during which the turf can start decomposing.

The process of an embodiment of the invention will now be described by reference to the flow chart of Figure 4. Steps above the dotted line in Figure 4 are carried out in the field whereas those below the dotted line are carried out in a processing plant.

- 18 Once a long roll of turf has been harvested, coiled together with the web (SI) and left on the ground (S2), another machine, such as a suitably modified fork lift truck, picks up the roll by its outer surface and either transports it to a processing plant (S3) or places it on a vehicle such as a lorry for transport to the processing plant.

At the processing plant, the turf is first uncoiled (S4) and separated from the web in which it is wrapped. This can once again be carried out by two mutually inclined conveyors, analogous to the previously described conveyors 20 and 22. The separated web is recyclable and therefore rewound onto rolls that can be returned to the harvesting machine (S5), when a fork lift truck or lorry returns to the field to collect the next rolled strip(s) of turf.

Because of the uncoiling of the roll, the harvested turf is cooled down and harmful respiration gases such as (CO2) are allowed to escape, thus enabling the turf to recover from any decomposition that may already have commenced. If desired, forced cooling may be used during the uncoiling of the rolls but often the natural cooling that occurs on exposure to the ambient air may suffice.

The strip of turf can now be processed in a processing line under controlled conditions with the processing bearing a greater resemblance to industrial production than agricultural production.

In the first step (S6) performed in the processing line, the strip passes through a station at which the grass on each turf piece is mowed to a desired height and the cuttings, and any other debris, on the surface of the turf pieces are removed by vacuum. The mowing ensures uniformity when the turf pieces are laid and the vacuuming removes matter likely to decompose and generate heat during storage and transportation.

- 19The turf may be advanced through the various processing stations by means of a conveyor belt and while passing through a cutting and vacuum cleaning station it is desirable to provide suction on the underside of the turf to ensure that the turf pieces do not lift off the conveyor belt as they are being cut or vacuum cleaned.

The first step (S6) may include further processing stations if desired, to treat the turf before it is analysed and cut into turf pieces. For example, it may be desirable to spray various solutions onto the turf to improve its quality.

A further possibility would be treat the turf to make it lighter, for ease of transportation and handling.

After passing through the various processing stations of the first step (S6), the strip may be subjected to quality control (S7). This can be done by a human operator or, more preferably, by cameras of which the video output is analysed by a computer using proprietary software that is programmed to recognise different forms of defect, for example by detection of image discontinuities or by colour analysis. For example, when harvesting uneven ground, the strip may have missing patches that can readily be detected. The video analysis may further detect other defects, such as weeds, which can be distinguished by their colour and/or shape.

In some embodiments, the visual analysis by computer may serve to grade the turf as to its quality, for example by colour analysis.

After the analysis step (S7), the strip of turf is cut into turf pieces (S8) and defective regions can be rejected (S9). While performing the analysis step (S7), it is possible for a suitably programmed computer to determine where best to cut the turf strip to maximise yield and minimise the regions of the strip to be rejected (S9) after they have been cut

-20(S8). Any rejected regions of the strip being processed may be diverted onto a discharge conveyor (S9), so that defective regions are removed from the main processing line.

Once the turf has been processed (S6) , subjected to quality control (S7 and S9) and cut into pieces of the desired size (S8), the turf pieces they may be palletised (S10) using conventional equipment, such as that currently to be found in harvesting machines. Hence, the turfs may be rolled individually and stacked on pallets. The uniformity of the turf pieces that can be achieved under controlled conditioned makes for neater pallets and the pallets may also be wrapped to safeguard them against damage in transit.

Turf pieces sold to landscape gardeners will generally be laid within a short time of delivery and longevity is not therefore of primary concern. However, turf sold to garden centres for resale to the public may benefit from being packaged differently. Embodiments of the invention permit different methods of packaging to be adopted to suit the intended purchaser and end user. Thus, if desired, the turf pieces may be individually wrapped or stacked flat. As a further alternative, by placing the turf pieces in stackable trays, they may be stacked in such a manner as to leave a space between them in order to delay or prevent decomposition.

If desired, the processing and in particular the packaging may be carried out under controlled conditions in order to prolong shelf life. In particular, the packaging may be performed at reduced ambient temperature and/or in a controlled gaseous atmosphere with increased nitrogen content and/or reduced carbon dioxide content.

Claims (31)

1. A process for the production of turf pieces having a desired length and capable of being laid in abutting relationship with one another to form a grass lawn, which process comprises:

harvesting from a field a strip of turf having a length significantly greater than the desired length of the turf pieces, .

coiling the strip into a roll in the field and, while coiling, inserting between the coils of the roll a web of a sheet material having high tensile strength to separate the soil side of each coil from the grass side of the adjacent coil, tension in the web being increased during coiling, transporting the roll from the field to a processing plant, and at the processing plant, uncoiling and cutting the strip into individual turf pieces of the desired length.

2. A process as claimed in claim 1, wherein at the processing plant the web is separated from the turf strip during uncoiling of the roll and returned to the field for reuse .

3. A process as claimed in claim 1 or claim 2, wherein further layers of the web are wrapped around a completed roll to protect the outermost coil on the roll.

4. A process as claimed in any one of claim 1 to claim 3, wherein the web has a continuous surface.

5. A process as claimed in claim 4, wherein the web is formed of a plasticised fibre-reinforced paper, tarpaulin or a polypropylene fabric.

-226. A process as claimed in any one of claim 1 to claim 5, wherein a leading edge of the web has a rigid member secured thereto to assist in threading of the web during coiling of the strip of turf.

7 . A process as claimed in claim 6 wherein the rigid member is a tube . 8 . A process as claimed in any one of claim 1 to claim

7, which further comprises, at the processing plant, analysing the uncoiled turf strip to identify defective regions, and cutting the turf strip into individual turf piece while rejecting defective regions.

9. A process as claimed in claim 8, wherein the analysing of the turf strip is performed by viewing the turf by means of at least one camera connected to an image processing computer programmed to detect image discontinuities .

10. A process as claimed in any one of claims 1 to claim 9, which further comprises, at the processing plant, mowing the harvested turf.

11. A process as claimed in claim 10, which further comprises vacuum cleaning the harvested turf after mowing.

12. A process as claimed in claim 10 or claim 11, wherein during mowing, and vacuum cleaning if applicable, the turf is held against a transport conveyor by suction.

13. A process as claimed in any one of claim 1 to claim 12, further comprising, at the processing station, spraying the turf with a treatment solution.

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14. A process as claimed in any one of claim 1 to claim 13, further comprising, at the processing station, processing the turf to reduce its weight.

15. A process as claimed in any one of claim 1 to claim 14, further comprising, at the processing station, packaging or palletising the turf pieces.

16. A process as claimed in claim 15, wherein the packaging or palletising the turf pieces is carried out under controlled temperature and atmospheric conditions.

17. A process as claimed in claim 16, in which the atmospheric conditions are controlled by reducing the carbon dioxide, and/or increasing the nitrogen content, of the ambient atmosphere.

18. A process as claimed in any one of claim 1 to claim 17, further comprising, at the processing station, retaining data on each batch of turf produced.

19. A process as claimed in any one of claim 1 to claim 18, further comprising, at the processing station, securing an RFID tag to each turf piece or pallet and maintaining a photographic record.

20. A turf harvesting machine comprising a vehicle having a cutting head for shaving a strip of turf from the ground, an elevating conveyor for raising the shaved strip from the level of the ground, a coiling station at which the strip transported by the elevating conveyor is coiled into a roll, and a web supply for feeding into the coiling station, under tension, a web of a sheet material having high tensile strength to be wound between the coils of the turf strip so as to separate the black soil side of each coil of turf from the green grass side of the adjacent coil and bind the coiled turf

-24into a roll, the web supply comprising a tensioning device for increasing the web tension during coiling of the strip.

21. A turf harvesting machine as claimed in claim 20, wherein in the coiling station the turf is coiled on itself to produce a coreless roll.

22. A turf harvesting machine as claimed in claim 20, wherein in the coiling station the turf is coiled onto a tube secured to the leading edge of the web.

23. A turf harvesting machine as claimed in claim 20 or claim 22, wherein the entire coiling station is displaceable relative to the elevating conveyor to enable a completed roll to be lowered substantially to ground level prior to being discharged from the harvesting machine.

24. A turf harvesting machine as claimed in any one of claim 20 to claim 23, wherein the coiling station comprises two mutually inclined conveyors, the angle of relative inclination of the two conveyors being variable as the size the roll of turf that is being formed increases.

25. A turf harvesting machine as claimed in claim 24, wherein a sensor is provided to measure the length of strip fed into to the coiling station, the mutual inclination of the coiling station conveyors being controlled in dependence of the measured length of the strip.

26. A turf harvesting machine as claimed in claim 24, wherein a sensor is provided to measure the size of the diameter of the roll being formed, the mutual inclination of the coiling station conveyors being controlled in dependence upon the measured size of the roll.

27. A turf harvesting machine as claimed in claim 24 or 26, wherein the speed of the elevating conveyor and of the

-25 conveyors of the coiling station are set automatically in dependence upon the measured ground speed of the harvesting machine .

28. A turf harvesting machine as claimed in claim 27, wherein means are provided to set the speed of the conveyor to exceed the ground speed of the harvesting machines by a factor to compensate for stretching of the turf.

29. A turf harvesting machine as claimed in claim 28, wherein the factor is adjustable by the operator of the machine .

30. A turf harvesting machine as claimed in any one of claim 24 to 29. wherein a sensor is provided to determine the height of a ripple in the turf upstream of the coiling conveyors, the sensor output serving to control the speed of the coiling conveyors so as to maintain the ripple at a desired height.

31. A turf harvesting machine as claimed in any one of claim 20 to claims 30, wherein the coiling station is mounted on the turf harvesting machine for pivoting movement about a horizontal axis between a roll forming position and a roll discharging position.

32. A turf harvesting machine as claimed in any one of claim 20 to claim 31, having two cutting heads to harvest two strips of turf side by side and further including sensors to determine the thickness of each harvested turf strip, the depth of the cutters being controlled in dependence upon the sensed thicknesses to ensure that the rolls grow in diameter at the same rate.

33. A turf harvesting machine as claimed in claim 32, wherein the sensors sense the thickness of the two turf strips directly.

-2634. A turf harvesting machine as claimed in claim 32, wherein the sensors sense the diameters of the two rolls for by rolling the two strips.

Intellectual

Property

Office

Application No: GB 1720272.2