The invention pertains to the laying of sheets of material, for example films, membranes, textiles and sheathing materials, on ground surfaces such as landfills to form a barrier between the ground surface and the environment.

Background of the Invention

The covering of landfills is a practice required by regulation in many jurisdictions. For example, it is often required that the daily fill of garbage be covered at the end of the day, or that the landfill be covered when it is not in operation. It is known in the art to lay strips of degradable film, such as polyethylene, in a side-by-side or

overlapping arrangement to cover the landfill, and to place an anchoring material (sometimes called ballast) such as dirt on the film to hold it in place. The ground area that requires regular covering in a landfill may be very large, and machines have been developed to apply strips of film to cover such areas. For example, Lammers et al. , US 5,536, 116 and US 5,620,281 , disclose an apparatus which is carried by a landfill compactor for laying and anchoring a film. Other examples in the patent literature include Brauer et al. , US 6,267,535 and Kozak, US 6,558,080. Such apparatuses have their limitations, including limited capacity to carry and dispense ballast, and an inability to handle large film rolls or to be adjusted for different widths of film. Typically, such prior art apparatuses require a separate vehicle to move them, such as a compactor. They may require frequent reloading of ballast,

compromising their efficiency in covering large ground areas. With high ballast load they may be unsafe in moving over unstable ground such as refuse. They also require the operator to drive the apparatus backwards in order to lay film, adding to the difficulty of the

deployment operation. There remains a need for effective apparatus and methods for efficiently applying strips of film to large areas of ground surfaces.

Summary of the Invention One aspect of the invention provides a machine for laying film or other sheet material on a ground surface and simultaneously depositing an anchoring material on the laid sheet.

The machine may be self-propelled and has a container for holding the anchoring material, the container having a front end and a back end, and means for moving the anchoring material toward the back end of the container. The container has an opening at its back end for release of the anchoring material therefrom. The machine has a first conveyor and a second conveyor separated by a gap, the two conveyors and the gap being arranged to receive the anchoring material released from the container opening. The machine has a holder for holding a roll of film for unwinding onto the ground surface as the machine moves, whereby the anchoring material may be deposited onto the film from the first and second conveyors and from the gap. The machine may have a film roll stabilizer to stabilize the roll of film from moving as it travels to or from the location of deployment.

Another aspect of the invention provides a method for laying a film or other sheet material on a ground surface and depositing an anchoring material on it. A machine as aforesaid is moved over the ground surface. The anchoring material is moved to the back end of the container and is released from an opening onto a first conveyor and a second conveyor, and into a gap between the first and second

conveyors. A strip of sheet material is unwound as the machine moves and the anchoring material is deposited from the first and second conveyors and from the gap onto the strip of material. The operation is repeated to lay successive strips of sheet material, which may be overlapping if required to create a barrier between the ground surface and the atmosphere, for example against liquids, gases, odors, dust, disease vectors, litter, etc.

Further aspects of the invention and features of specific

embodiments of the invention are described below.

Brief Description of the Drawings

Figure 1 is a side perspective view of the a machine according to one embodiment of the invention.

Figure 2 is a partially cut-away back elevation view thereof.

Figure 3 is a partially cut-away top plan view thereof. Detailed Description Throughout the following description and the drawings, specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. The description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. An embodiment of the film-deploying machine and method of the invention is described below in respect of applying a film to a landfill. This is only one example of a practical application of the invention. The invention is suitable for use in other applications where there is a need to create a barrier at the ground surface, for example to reduce run-off or environmental contamination, or to contain gases under and/or above the ground surface. Such applications include those in the farming, mining and road construction industries. Referring to Figure 1 , the film-deploying machine 20 is a motorized, self-propelled tracked vehicle having an operator's cab 22 at the forward end of the vehicle, a track 24 and a frame 26 supporting a box or container 28. The track may have rubber track plates. The box 28 has side walls 30, a front wall 32 behind the cab and an end gate 34 at the back end. The end gate 34 is vertically movable by means of hydraulic cylinders.

The box 28 has a hydraulic chain floor 38, best seen in Figures 1 and 3, for moving anchoring material towards the back end of the box for removal, as described below. The box is sufficiently large that it can carry a large volume of anchoring material to the area of

deployment, thus increasing the efficiency of the deployment operation. The anchoring material 112 may comprise dirt, clay, gravel, sand, crushed stone, sludge, recycled waste such as pieces of asphalt, or other materials suitable for a particular application.

The chain floor 38 comprises a floor panel 40, a front roller 42 at the front end of the floor, i.e. the end adjacent to the cab, and a rear roller 44 at the back end of the floor, the rear roller being driven by a hydraulic motor 46. Two spaced-apart pairs of chains 48 engage sprockets 45 on the floor rollers 42, 44 and extend around the floor rollers and the floor panel 40, forming continuous loops running above and below the floor panel 40. Each pair of chains is connected by a plurality of spaced-apart bars 50 extending transverse to the longitudinal axis of the machine. The bars 50 are rectangular in cross section and may be about 1.5 inches (3.8 cm) in height, being adapted to engage and move anchoring material. Bars of greater or lesser heights can be employed, depending on the intended volume of anchoring material to be moved at a given speed of rotation of the chain floor. As the rear roller 44 is rotated, the chains and accordingly the bars 50 are moved rearwardly along the top surface of the floor panel, moving anchoring material in the box toward the end gate.

When the end gate is raised, there is an opening 52 between the floor panel 40 and the lower edge of the end gate 34, through which the anchoring material can pass. The height of the opening 52 is

controllable by the operator by actuation of the hydraulic cylinders 36, to regulate the flow of anchoring material out of the box. Optionally, a flexible rubber strip (not shown in the drawings) may be attached to the end gate along its lower edge, partly covering the opening 52, to reduce leakage of small pieces of the anchoring material when the vehicle is being moved after laying one strip of film into position to lay a further strip. The box 28 also has a center gate 54 about half-way between the front wall 32 and the end gate 34, extending between the side walls 30. There is a space 56 between the floor panel 40 and the lower edge of the center gate. The vertical position of the center gate is manually adjustable to adjust the height of the space 56. The center gate is used to regulate the movement of anchoring material within the box as the chain floor is operated. An anchoring material distribution module 58, best seen in

Figures 2 and 3, is disposed at the back end of the box 28. It comprises a frame 60 with two side panels 62, a top panel 64 and a rear panel 66. Two conveyors 68, 70 are disposed in the frame 60, separated by a gap 72 and oriented transverse to the longitudinal axis of the machine. The conveyors 68, 70 comprise conveyor belts 74, 76 and associated rollers and hydraulic motors. The belts 74, 76 are positioned below the rear roller 44 of the chain floor, so that anchoring material that falls off the back end of the chain floor falls onto the belts 74, 76 and into the gap 72 that separates them. In use, the belts 74, 76 are driven a direction so as to convey the anchoring material towards to the outer ends 78, 80 respectively, of the conveyors.

A pair of deflector plates 82 is provided at the back end of the box, adjacent to the inner ends of the conveyors 68, 70, to regulate the amount of anchoring material that is directed toward the gap 72, as opposed to toward the belts 74, 76. The position of the deflector plates is manually adjustable. Two film roll support arms 84, 86 are disposed on the frame near the back end of the box 28, each extending laterally outward from a respective side of the machine. The support arms may be locked in selected positions such that the distance between the respective outer ends 88, 90 of the arms may be varied to accommodate films of different widths and diameters. A lockable pulley and cable mechanism 92 is provided at each outer end 88, 90 of the support arms.

The film roll holder includes a metal tube or spool 96 on which is placed a roll 94 of film 95, the inner diameter of the roll being larger than the outer diameter of the tube, so that the roll can rotate on the tube as the film is unwound. The film may be any suitable plastic film, for example a poly olefin such as polyethylene, and it may be

degradable. An end cap or top hat structure 98 is positioned over each end of the tube 96 adjacent to the ends of the roll 94. The end cap has a flange section 100 which fits over the tube 96 and is removably locked to it, and a circular plate 102. The end caps hold the film roll in position on the metal tube 96. The end cap has a support ring 104, and a cable hook 106 clips to the support ring for supporting the roll of film under the support arms 84, 86. The vertical distance between the roll of film and the support arms, or between the roll and the ground, is manually adjustable by means of the pulley and cable mechanisms 92.

Two film roll stabilizers 107 are provided, one adjacent to each outer end 88, 90 of the support arms 84, 86. The film roll stabilizers comprise a vertical member 108 and an angled holding member 109 which fits over the film roll. The film roll stabilizers 107 are used when the machine 20 is traveling without deploying film, in order to stabilize the roll. This is accomplished by winching up the roll until it fits snugly against the holding members 109 and locking it in that position by the pulley and cable mechanism 92. The roll is lowered for deployment of the film.

Three clips 110 are arranged at the back of the distribution module 58 for attaching the end of a strip of film when commencing deployment, and after a stip is laid and cut, as further described below.

The cab 22 includes operator controls for actuating the chain floor 38 and the conveyors 68, 70, for raising and lowering the end gate 34, and for controlling the direction and speed of the vehicle. The operator can accordingly control the amount of anchoring material deposited on a given length of film strip. Strips of film 95 are deployed using the machine 20 in the following manner. Anchoring material 112 is loaded into the box 28 and a roll of film of a selected width, for example 16 feet (4.9 meters), is suspended from the support arms 84, 86, hanging out of contact with the film roll stabilizers 107. The free end of the strip of film is attached to the three clips 110, forming a loose length of film below the

anchoring material distribution module 58, as shown in Figure 1. The two outer clips 110 are attached to respective longitudinal edges of the strip and the middle clip 110 is attached to the middle of the strip. The length of film hanging between the three clips and the film roll forms a pocket to catch the anchoring material that initially falls onto it. The end gate 34 is raised to form the opening 52 and the chain floor 38 and conveyors 68, 70 are actuated. As anchoring material falls through the gap 72 and off the outer ends 78, 80 of the conveyors, it falls onto the hanging length of film. The weight of the anchoring material pulls the film to the ground surface, holding it there. The vehicle 20 is then driven forward, i.e. to the right in the view of Figure 3, tearing away the free end of the film from the clips 110. As the vehicle advances forward, film is unwound from the roll, laying a strip of film on the ground behind the machine, and three lines of anchoring material are deposited on the strip, one along the center line from anchoring material falling through the gap 72, and one line near each longitudinal edge of the strip from the material falling off the outer ends 78, 80 of the conveyors.

Depending on the width of film being use, chutes may optionally be provided at the outer ends 78, 80 of the conveyors 68, 70 to direct the two outer streams of anchoring material to a position adjacent to the edges of the film strip. For example, outwardly-extending chutes may be used if the width of the film is substantially greater than the distance between the outer ends 78, 80 of the conveyors. Alternatively, the speed of the conveyor belts may be increased or decreased to control the position of the streams of anchoring material thrown from the ends 78, 80 of the conveyors.

When the machine 20 has laid a strip of film to the end of the landfill working face or other selected position, the machine is stopped and the strip is cut, either manually or by automated cutting means. The free end of the strip of film on the roll is attached to the clips 110, so the film is in position to receive anchoring material. The machine is then moved into position to lay a second strip parallel to the first strip and adjacent to or overlapping it. The operation is repeated until the desired ground area has been covered. The strips would be applied in overlapping manner for applications that require a continuous, impermeable barrier at the ground surface.

In another embodiment of the invention (not illustrated in the drawings) the film-deploying machine is configured to lay a sheet material that is sufficiently heavy that it does not require anchoring material to hold it on the ground, for example a heavy rubberized sheet material. In this embodiment, the machine does not have a box for holding and releasing anchoring material or an anchoring material distribution module and associated controls. The machine is otherwise the same as the vehicle 20 as described above. In use, this embodiment of the machine simply advances forward and a strip of the heavy sheet material is unwound from the spool 96 onto the ground surface behind the machine.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the scope thereof. Possible alterations and modifications include, without limitation: Instead of being self-propelled, the machine may be propelled by means of towing by a compactor, loader other vehicle.

The conveyors in the anchoring material distributor module may be augers or other structures, rather than belts.

Instead of a chain floor in the box, the means for moving anchoring material to the back of the box may be any other practical material-moving means such as conveyor belts or augers.

A second holder for suspending a roll of film may be provided at the front end of the machine. Film unwound from this roll would be run over by the tracks of the vehicle as it moves forward.

Instead of a film, the sheet material deployed may be any sheet material that is suitable for a particular application, for example textiles, sheathing materials, textiles, woven and unwoven materials, etc.

Optionally, anchoring material deflector plates can be provided at the gap 72 to divide the anchoring material that falls through the gap into two streams, so two lines of anchoring material from the gap are laid on the film, rather than one.

Accordingly, the scope of the invention is to be construed in accordance with the following claims: