Technical Field

The present invention relates to a method of positioning a protective sheet to cover a stack of goods, the stack of goods comprising the protective sheet in place, the protective sheet, and the support for delivering the sheet into position. Background and prior art

It is estimated that the demand for straw for use in biofuel power stations will be

approximately 1 million tonnes per year by 2018. This has resulted in a market developing for providing large quantities of straw.

Straw is typically grown and then harvested and formed into bales. A number of such bales are typically stacked together to form large stacks for example with a height of 10 metres. Such stacks then remain in place until it is desirable or timely to transport the material to a power station for consumption.

As such, these stacks of straw may spend a considerable time outside exposed to the elements. In particular rain water can cause wastage and rot of the top layer of straw bales. Such wasted bales are typically disposed of at zero value to the grower. It would be desirable therefore to cover the stack of straw with e protective sheet or similar. However in view of the height of such stacks, it is not safe or even legal sue to health and safety legislation, to send a human being up to place a protective sheet onto such a stack.

Additionally, such stacks are often so large that they have a risk of bales coming loose or even being toppled by high winds, resulting in further loss of valuable product.

Therefore there exists a need for reducing the wastage that naturally occurs in such stacks.

Summary of Invention

In a first aspect, the invention relates to A method of positioning a protective sheet to cover a stack of goods having first and second opposing sides and a top surface, (a) the protective sheet comprising first and second opposing parallel sides, each side comprising an attached first and second rigid elongate member extending substantially the entire length of each respective parallel side of the sheet, each rigid elongate member having attached at least one securing strap and at least one positioning strap, with

(b) a lifting device comprising a support for mounting the first rigid elongate member in a substantially horizontal orientation, the support comprising at least one positioning strap projector; the method involving the steps of:

(1) engaging the lifting device to lift the first rigid elongate member adjacent to a first side of the stack of goods, while the first rigid elongate member remains substantially horizontal, wherein the at least one positioning strap attached to the first rigid elongate member being lifted is loaded into a respective at least one positioning strap projector, until the first rigid elongate member is positioned above the top surface of the stack of goods;

(2) projecting the at least one positioning strap from the at least one positioning strap projector, such that the at least one positioning strap passes over the top of the stack and down the second side of the stack;

(3) securing the at least one positioning strap and disengaging the first elongate rigid member from the support so that the sheet is free of the lifting device;

(4) applying tension to the at least one positioning strap so as to pull the first

elongate rigid member across the top surface of the stack of goods towards the second side of the stack of goods whilst also lifting the second elongate rigid member up the first side of the stack of goods;

(5) once the sheet is in place over the top surface of the stack of goods, securing the at least one securing strap depending from both the first and second rigid elongate members to a respective location at or near the base of the first and second side of the stack of goods respectively.

In a second aspect, the invention relates to a stack of goods having first and second opposing sides and a top surface substantially covered by a protective sheet, the protective sheet comprising first and second opposing parallel sides, each side comprising an attached first and second rigid elongate member extending substantially the entire length of each respective parallel side of the sheet, each rigid elongate member having attached at least one securing strap, wherein the first and second rigid elongate members are located at or near the top of the first and second sides of the stack of goods, and the securing straps are secured to a location at or near the base of the first and second side of the stack of goods respectively.

The goods can be any perishable goods that are formed into a stack that could be expected to be exposed to the elements. Typically, the goods are bales of straw or hay but could be other perishable goods such as wood. The present invention is particularly suitable to large stacks of goods. Thus, preferably the stack of goods is greater than 5m, more preferably greater than 8m tall.

In a third aspect, the invention relates to a protective sheet for covering a stack of goods the protective sheet comprising first and second opposing parallel sides, each side comprising an attached first and second rigid elongate member extending substantially the entire length of each respective parallel side of the sheet, each rigid elongate member having attached at least one securing strap.

The rigid elongate members may take a variety of forms, however a convenient form is a metal tube.

The present invention is particularly suitable for large sheets, and thus preferably the sheet covers an area greater than 100m ² . Each opposing side should have sufficient securing traps according to the prevailing needs. However it has been found that from two to eight securing straps is generally sufficient.

In a fourth aspect, the invention relates to a support for a lifting device for lifting a protective sheet as described herein, the support comprising

(a) a horizontal support bar comprising a mount for reversibly mounting an elongate rigid member in a substantially horizontal orientation

(b) at least one positioning strap projector.

The support preferably comprises two positioning strap projectors, as this provides a means to evenly pull the sheet over the top surface of the stack, however there could be more than two. The positioning strap projectors are preferably operable by catapulting a coil of positioning strap.

Thus, the present invention provides a method for positioning a protective sheet to cover a stack of goods, which can be applied to even very high stacks, without the need for sending a human being up onto the stack.

Furthermore, the invention provides a means of securing the protective sheet to the stack at high levels of tension and thus mechanically strengthening such a stack to prevent it from being damaged or destroyed by high winds.

The invention will now be illustrated by reference to the accompanying figures, in which:

Figure 1 is an image of a support for use with the present invention.

Figure 2 is an image of a securing strap projector mounted on a support.

Figure 3 is a perspective view of a portion of a protective sheet according to the present invention.

Figure 4 is an image of a stack of goods about to be covered by a protective sheet.

Figure 5 is an image of the stack of goods shown in figure 3, as a protective sheet is lifted along one side of the stack of goods.

Figure 6 is an image of the stack of goods shown in figure 3, wherein the protective sheet is above the top surface of the attack of goods.

Figure 7 is an image of the stack of goods shown in figure 3, wherein the securing straps are being projected by strap projectors.

Figure 8 is an image of the stack of goods shown in figure 3, wherein the protective sheet is free from the lifting device and the securing straps are secured.

Figure 9 is an image of the stack of goods shown in figure 3, wherein the sheet has been pulled to cover the top surface of the stack of goods with the protective sheet in its final covering position.

Figure 10 is an image of the stack of goods shown in figure 3, wherein the sheet is secured in place by tensioning the securing straps.

Turning to the figures, figure 1 shows a support 10 attached to a lifting device 12, which in this case is a commercially available 17m telehandler. The support comprises a horizontal beam 18, which comprises a box section with another such box section beam inserted therein to provide a telescopic function, and a number of depending bent metal rods 20, so that they can support an elongate metal pole 22, which can act as a rigid elongate member according to the invention. The support also comprises two positioning strap projectors 14, 16 fixed 3.6m from the centre of horizontal beam 18 operated by a 12 volt battery located in the centre of the support 12. The strap projectors are arranged to be activated remotely e.g. from the ground.

The telehandler 12 comprises a boom extension, which is a 10mm thick right angle plate locked in by securing clips.

Figure 2 shows a close up image of one of the strap projectors 14. As can be seen there is provided a holder 24 for containing a coil of positioning strap 25. The positioning strap is

50mm wide nylon. One end of securing strap 25 is attached to pole 22. Holder 24 is adapted to be rotatable about a horizontal axis, located by nut 27. Also provided is a control box 28 which actuates the holder 24 when a command is sent remotely e.g. from the cabin of telehandler 12.

In use, the control box 28 actuates the holder 24 to rotate rapidly in a counter-clockwise direction from the perspective of Figure 2. This has the effect of the coil of positioning strap 25 leaving the holder 24 and being projected and unravelled at the same time. Thus the coil of positioning strap is catapulted or thrown.

Figure 3 shows a protective sheet 30 according to the present invention. At one end the sheet material is folded and stitched onto itself to create a sheath 32 so that pole 22 can be inserted therein. Also provided are five cutouts 34 to provide access to the five securing straps 26 attached on the pole 22. The cutouts also are located where the bent metal rods 20 of the support engage with the pole 22.

As the positioning straps 25 need to extend along one side of the stack 40 and a portion of the top surface, they are generally longer than the securing straps 26 that only need to extend down one side of the stack.

In a further refinement, the sides of the sheet 30 are also folded in to create sheaths 31 down the sides. Into these sheaths 31 are inserted side straps 33 which extend along the sides and are looped around the pole 22. Importantly, the straps 33 are a distance, e.g. 20mm from the end of sheath 32. This has the effect that when pole 22 is pulled by securing straps 26 the side straps 31 are pulled in tight before the rest of sheet 30. This allows the sides of the sheet to bite into the stack and provide a tight fit on the sides of the sheet 30. Figure 4 shows a stack of straw bales together forming a stack of goods 40 according to the present invention.

Also shown is the lifter 12 having mounted thereon the support 10 as discussed in relation to figure 1. In this arrangement sheet 30 is provided which is rectangular in shape and generally in accordance with the sheet described in relation to figure 3.

As such the two positioning straps 25 are wound into a coil and placed into securing strap projectors 14, 16. Their outer end is secured to the pole 22 at one of the cutouts 34.

The lifter 12 then lifts the support 10 which lifts the rigid elongate pole 22 which in turn lifts the sheet 30 upwards adjacent to the first side of the stack of goods 40, as can be seen in figure 5. The lifter then continues to raise the support 10 and pole 22 so that the pole is located approximately centrally above the top surface of the stack of goods as shown in figure 6.

Once in position, the strap projectors 14, 16 project the coils of positioning strap over the top surface of the stack 40 and down the opposite side of the stacks as can be seen in figure 7.

The ends of the positioning straps are then secured, in this case to a second telehandler 42. Second telehandler then tensions the positioning straps 25 so that pole 22 is pulled out of the retaining feature of the bent metal rods 20. This has the effect of the pole 22 falling onto the top surface of the stack of goods, as can be seen in figure 8. Alternatively the positioning straps could be pulled by a winch.

The telehandler 42 continues to tension the positioning straps 25 until the protective sheet is in place over the top of the stack 40, as seen in figure 9. To finalise the positioning of the sheet, metal rods (not shown) are inserted into the body of bales at the base of the stack. The positioning straps 25 are removed from the pole 22 and the ends of the securing straps 26 are attached to the metal rods. A ratchet device can be added to the ends of the securing straps 26 at this point so that more tension can be applied to the securing straps 26. The end result is a protected stack as shown in figure 10.

As the securing straps are attached to the rods 22 and not directly to the sheet material, there is no danger of tearing of the sheet, even if high levels of tension are applied to the securing straps. This has the effect that a very tight and compact structure can be produced which provides stability to the stack as shown in figure 10.

In an alternative embodiment, instead of having five securing straps and two positioning straps, it would be possible to have five securing straps, a number of which also act as positioning straps. Clearly the positioning straps need to be longer than securing straps, so this arrangement would result in the straps that acted as both securing and positioning straps being a little longer than necessary in the final finished covered stack.