Graders such as root crop graders are used to sort out various sizes of (root) crops. One example is a potato grader. Various improvements in moulded conveyor webs are described in GB9305681, GB9512792 and GB9622077 which involve using a web (sometimes also termed a"screen") to sort the relevant crop into sizes for different markets. The web consists of plastic links making up squares, hexagons or circles, etc, of the required size. These are supported by steel rods running through the links with the ends bonded into rubber traction belts on the outside edges of the web. The rubber belts keep the links in place, and more importantly, provide a means for driving the web using rollers at the edges of the grader.

However, manufacture of the webs is very time consuming and inefficient. Moulding and bonding the belts to the assembled rods and links requires a gap to be left in the link pieces to accommodate the moulding tool. This gap requires to be covered up after moulding which is a time consuming exercise.

The cover pieces also tend to fall off in service due to flexing of the web.

Customer demand for various sizes and shapes of web also varies wildly. This makes the market in each web a low-volume market such that economically, such webs can only be made to order.

It is an object of the present invention to overcome this disadvantage and provide a web that could be stored in component form.

According to one aspect of the present invention, there is provided a web comprising a plurality of link pieces, a plurality of supporting rods adapted to run through the link pieces, and one or more end- belts adapted to support the supporting rods, wherein the supporting rods are secured to the or each belt by a push-fit connection.

The push fit connection is based on a simple mechanical process compared with the equipment and apparatus needed to bond'supporting rods into traction belts as is currently conducted. Thus, the components of such webs can be stored in component

form, and simply assembled anywhere, including on site, rapidly and easily to meet the customer specification as to size and shape of the web. The present invention also provides the advantage that the belts can be made separately.

Thus, according to a second aspect of the present invention, there is provided a kit for assembly of a web comprising a plurality of link pieces, a plurality of supporting rods adapted to run through the link pieces, and one or more end-belts, wherein the supporting rods are secured to the or each belt by a push-fit connection.

The link pieces may be of any suitable shape, size or design as is known in the art.

The supporting rods may be of any suitable size, shape or design as is known in the art. In general, the supporting rods are made of metal such as steel, in particular stainless steel, but may also be plastic and/or tubular.

The belts may be of any suitable size, shape or design. Such belts are generally made of rubber or other elastomeric material and are designed to provide the means of driving the web around two or more rollers.

The mechanical push-fit operation of the supporting rods into the or each belt may involve integral or

separate means adapted to secure the end of the supporting rods into the or each belt. The or each belt may include pockets or apertures adapted to receive the ends of the supporting rods either partly or fully through the belt.

The ends of the supporting rods may be secured to the belts directly by design of the belts, or by use of intermediate fastening or fixing means such as push- fit clips, washers, bushes, rings, nuts, sleeves and the like. These could be plastic or metal.

Any intermediate fastening or fixing means may be within or outside the belts. More than one intermediate means may be used, or such means may comprise more than one clip, etc. The fastening or fixing means could have one or more moveable and/or deformable portions adapted to allow ease of insertion of a rod therethrough, but no similar ease of opposite movement.

The fastening or fixing means could be held in a retainer means to support the or each fastening or fixing means prior to engagement with the belt. The retainer means could even be moulded into or with the belt. The retainer means could have one or more aligned slots, slits, etc, designed to retain a plurality of the fastening or fixing means in an aligned manner.

If necessary or desired, additional means can be used to secure the supporting rods to the or each belt such as additional mechanical fixing or fastening means, or bonding means such as adhesive.

According to a third aspect of the present invention, there is provided a method of forming a web comprising a plurality of link pieces, a plurality of supporting rods adapted to run through the link pieces, and one or more end-belts adapted to support the supporting rods, wherein the supporting rods are securable to the or each belt by push-fit operation.

The web of the present invention may be used in any conveying, grading or destoneing operation. Grading is a common part of harvesting many crops, e. g. root crops such as potatoes and carrots, fruit or vegetables such as onions.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a plan view of a fully formed potato grader web; Figure 2 is a cross-sectional view of three supporting rods under a perpendicular traction belt using the present invention; Figure 3 is a side view along line A-A in Figure 2;

Figure 4 is an expanded view of a typical securing clip shown in Figure 3; Figures 5a and 5b are cross-sectional views of a sleeve for use with the present invention; Figures 6a-6d are views of a retaining frame for use with the present invention; and Figures 7a and 7b are plan and cross-sectional views of a conveying web according to the present invention.

Referring to the drawings, Figure 1 shows a potato grader web having a plurality of link pieces 2, a plurality of perpendicular supporting rods 4 through the link pieces 2, and two end rubber traction belts 6 supporting the ends of the supporting rods 4. The link pieces are put together to form squares of desired shape and size, and the supporting rods 4 keep the link pieces 2 together, while still providing flexibility of the lines of link pieces 2 as is required.

Currently, the supporting rods 4 are bonded into the end belts 6, which bonding requires significant equipment and apparatus, and also requires significant finishing and assembly operations. Thus, there is no flexibility in rapidly and easily forming different shapes and designs of grader webs to more immediately meet the varied customer demand.

Figure 2 shows three supporting rods 10 according to the present invention. The right hand supporting rod l0a is shown ready for insertion and securement into a first aperture 12 through a traction belt 14.

Surrounding the first aperture 12 are three securing or retaining clips 16, also shown in Figures 3 and 4.

Figure 2 shows a middle supporting rod 10b already inserted into a second aperture 12 and retaining clips 16, and a third supporting rod 10c similarly secured into the belt 16 in a blind hole 18, rather than through aperture 12.

As shown in Figures 3 and 4, the retaining clip 16 is generally circular, with a central aperture 19, and slots regularly extending from the central aperture to form a number of fingers'20 thereinbetween. The fingers 20 are moveable. The central aperture 19 is slightly smaller than the cross-section of the supporting rods 10, such that insertion of a supporting rod 10 through a retaining clip 20 forces slight outward movement of the fingers 20, which are then biased against the supporting rod 10 and so secure the supporting rod 10 to the belt 14.

No mechanical preparation of the ends of the rods is necessary as the clips 16 are designed to grip a smooth surface. Moreover, reverse movement of the supporting rods 10 is wholly or substantially not possible due to the grip of the fingers on the supporting rods 10.

The securing clips can be produced as a special one- piece pressing which will reduce the manufacturing time and cost. A single pressing or other forming process may produce more than one clip simultaneously.

Figure 5a shows a sleeve 22 formed with three sets of circular inserts 24, each insert having deformable portions 26.

Figures 6a to 6d show a retaining frame 30 having a U-shaped section in which there are three slits. In each slit can be placed a push-fit clip 32. The frame 30 can be inserted into suitable apertures in a belt 34, or moulded during formation of the belt 34.

At one end of the frame 30 is and end flap 36 to act as a solid end-stop for a rod 38. The frame 30 ensures accurate spacing of the clips 32 during either the moulding and/or insertion process.

The present invention provides a simple and rapid method of conjoining supporting rods with the belt or belts of a web which can be carried out by any person, and does not require any significant equipment or apparatus. Thus, the supporting rods and belts can be stored separately, ready for conjunction when the relevant link pieces are put together to from the required size and shape of web.