GB2290515A

GB2290515A - Open web conveyor connectors

Info

Publication number: GB2290515A
Application number: GB9512792A
Authority: GB
Inventors: Peter James Wood; Jeffery John Sanderson
Original assignee: Reekie Manufacturing Ltd
Current assignee: Reekie Manufacturing Ltd
Priority date: 1994-06-24
Filing date: 1995-06-23
Publication date: 1996-01-03
Also published as: GB9512792D0; WO1996000353A1; GB9412773D0; AU2748195A

Abstract

An open web suitable for use in a potato harvester comprises at least two belts (11) having embedded therein end portions of a plurality of rods (12) mounted across the belts in spaced parallel relation. The belt ends (22, 24) have male and female portions (23, 25) formed therein and the belts include tensile reinforcing layers and/or cords extending longitudinally in the belts. In one embodiment, the male and female portions (23, 25) are of complementary dovetail configuration and the ends of the reinforcing cords are secured to connecting members moulded in the male and female portions. Alternatively, the cords are secured around end portions of rods (12) which extend through outer metal casings provided on the male and female portions. In another embodiment, two male belt ends are connected by a steel member having two female portions and reinforcing cords in the belts are captively connected to the steel member via connecting rods passing through apertures in the steel member and the belt ends. <IMAGE>

Description

OPEN WEB CONNECTOR The present invention relates to open webs of the type often referred to as continental webs, which are widely used in agricultural machinery for conveying and cleaning root crops and other farm produce, stone and clod separation etc, and more particularly to connectors suitable for use therein.

Conventional webs 1, as shown in Fig. 1, generally comprise a plurality of rods or bars 2 mounted in parallel spaced apart relation across two or more parallel spaced apart belts 3. The rods 2 are of rounded section which is flattened 4 at connecting portions 5 which are provided with holes 6 through which extend rivets 7 which also pass through the belts 3 and clamping plates 8 so as to secure the rods 2 to the belts 3.

The above described form of construction is however plagued with numerous weaknesses which result in relatively poor web reliability. Thus for example breakages frequently occur at the junctions between the rounded and flattened parts of the bar, and within the flattened portions at the rivet holes, and the rivets themselves also lose their heads and/or break between their ends. The assembly of the rods and belts and riveting together thereof is relatively cumbersome and labour intensive. In addition the riveting process is susceptible to inaccurate positioning of the rivets and thereby the rods which results in incorrect spacing of the rods.This in turn leads to crop loss through over-sized inter-rod gaps, as well as strain on the rod-web interconnection at the under-sized inter-rod gaps where the rods tend to be forced apart by the drive sprocket teeth which engage the bars to drive the web, thereby also increasing the risk of premature failure. Having regard to the dramatically increased intensity in the use of agricultural machinery with very large areas of land having to be harvested or cleared of stones and clods, in a short period of time, it will be appreciated that any down-time at all resulting from the abovementioned kind of failures can have serious economic consequences to the farmer or contractor.

In our earlier patent application numbers GB9305681.0 and PCT/GB94/00520 there is disclosed an open web suitable for use in conveying and separating bodies such as root crops and stones and clods, which web comprises at least two elongate belts extending parallel to each other in substantially spaced apart relation, and a plurality of rods mounted in parallel spaced apart relation across said belts with connecting portions of said rods secured to said belts, characterized in that said connecting portions are substantially embedded within the body of said belts and secured thereto by bonding of said belts to said connecting portions.

In those applications the belt end portions are shown to be connected in generally conventional manner as illustrated in Fig. 3a of the accompanying drawings with hinge lugs 17 through which are threaded connecting rods 18. Figure 3b illustrates an alternative conventional arrangement for belt end connection, also utilising hinge lugs 17 and connecting rods 18. These known types of interconnection does however have certain limitations in that the full load in the belts has to be borne by the connecting rods. It may also be seen in Fig. 3 that the hinge lugs 17 extend longitudinally a substantial distance into the belts (or in Fig. 4, over the belt ends) thereby significantly reducing belt flexibility in the region of the belt end interconnections thereby increasing wear in the belts.

It is an object of the present invention to avoid or minimize one or more of the above disadvantages.

The present invention provides an open web suitable for use in conveying and separating bodies such as root crops and stones and clods, which web comprises at least two elongate belts extending parallel to each other in substantially spaced apart relation, and a plurality of rods mounted in parallel spaced apart relation across said belts with connecting portions of said rods substantially embedded within the body of said belts, said elongate belts having longitudinally extending therethrough tensile reinforcing means and having end members formed and arranged for connecting together with respective end members of the same or further said belts for forming respective endless elongate belts extending parallel to each other, characterized in that said end members have respective ones of substantially complementary male and female portions formed within the width of said belts, said male portions having head members for captive retention within said complementary female portions transversely of the belts in the plane of the respective endless belt thereat, said end members having captively inter-engaging connector means to which said tensile reinforcing means are captively connected.

In one embodiment the connection means may be constituted by a said connecting portion of a said rod extending through respective apertures in said male and female portions.

Advantageously said male and female portions are provided with reinforcing member means secured to the belt ends, in which reinforcing member means said apertures are formed, and to which said reinforcing means are captively secured.

Various forms of reinforcing member means may be used. Thus for example there may be used a stiffening means having web portions disposed internally and/or externally of a belt end in which said male or female portion is defined.

Alternatively there may be used reinforcing members in which the male and female portions are formed. It will moreover be appreciated that various combinations of the above may be used. Moreover one belt end may, in effect, be provided with a composite reinforcing member means with a separate connecting member having a male or female portion at one end of the connecting member for connection to the female or male portion of another belt end, the other end of the connecting member having a male or female portion connected to a female or male portion of said one belt end.

Preferably said connector means and said end members are formed and arranged so as to enable said male and female portions to relatively pivot.

Where said rod connecting portion extends through part of the belt itself, the latter may be provided with reinforcing member means comprising a bush which is secured within the belt, defining an aperture therein in which said rod connecting portion is received.

Said connecting portion of said rod constituting the connector means may be bonded to said male and/or female portions.

In another type of embodiment of the present invention the connector means has a male portion with an enlarged head portion extending from a narrower neck portion, whereby said head portion is captively retained longitudinally of the belt, in the complementary female portion. Various shapes of male/female portion may be used. Conveniently a dovetail type of configuration may be used. With this type of connector means it is not necessary to utilize a rod connecting portion extending through the interengaging male and female portions to retain them together against longitudinal disengagement, though if desired this can be included to provide greater security. Insofar as in this type of arrangement the tensile forces longitudinally of the belt are carried by the interengaging male and female portions, disengagement of the portions by relative movement perpendicular to the principal plane of the belt may be prevented by a relatively lightweight retaining pin or other suitable means.

As before, the male and female portions may be defined in the ends of the belt itself or in reinforcing member means secured thereto. In the former case the male and female portions may be provided with external reinforcing member means comprising a metal or other generally rigid, casing.

According to another aspect, the present invention provides an open web suitable for use in conveying and separating bodies such as root crops and stones and clods, which web comprises at least two elongate belts extending parallel to each other in substantially spaced apart relation, and a plurality of rods mounted in parallel spaced apart relation across said belts with connecting portions of said rods substantially embedded within the body of said belts and secured thereto by bonding of said belts to said connecting portions, said elongate belts having end portions formed and arranged for connecting together with respective end portions of the same or further said belts for forming respective endless elongate belts extending parallel to each other, characterized in that said end portions have respective ones of substantially complementary male and female portions, said male portions having substantially enlarged heads for captive retention within said complementary female portions longitudinally of the belts, said male and female portions having transversely extending passage means for receiving therethrough retaining rod means extending across said belts parallel to said plurality of rods, for captive retention of said male and female portions against transverse disengagement.

With the open web of the present invention it is possible to reduce the extent of the belt-end inter-connections longitudinally of the belts thereby improving flexibility of the belt and reducing wear and damage associated with reductions in belt flexibility, whilst at the same time providing high strength belt-end interconnections.

Preferably either or both of the male and female portions are provided with internal reinforcing. The generally flexible belt material itself may be locally reinforced thereat by incorporation of suitable material such as ( sir) chopped fibres e.g. of Kevlar(Trade Name), so as to harden and rigidify the male and female portions to limit compressibility and flexibility thereof and reduce the possibility of unintentional disengagement thereof.

Advantageously said tensile reinforcing means extending longitudinally through said belts is constituted by one or more reinforcing layers e.g. of woven textile material such (RrM) as kevlarl; polyamide e.g. nylon, or polyalkene e.g.

polypropylene, or glass fibre etc. Steel mesh reinforcing layers may also be used. Desirably such a reinforcement layer has an open weave or open mesh in the range of from 40% to 80% preferably 60%. Preferably such a reinforcement layer is tied-in, in one way or another, to the male and/or female portions, for example, by providing an enlarged head portion for mechanical interlocking or captive retention within a male portion or an enlarged head section partly defining a female portion, so that said tensile reinforcing means are captively connected to the captively interengaging connector means. Alternatively, or additionally, a reinforcement layer can be bonded or otherwise secured to an external casing provided on the male and/or female portion.

In order to protect reinforcing layers of woven textile material, such as kevlary, included in the belts, such reinforcing layers may be woven of rubber-coated textile material e.g. rubber pre-coated kevlar; The rubber coating acts to protect the textile material from fraying which may be inclined to occur due to friction between the reinforcing layer and the plurality of parallel rods, which are preferably made of metal, usually steel. Alternatively the rods could be made of plastics material e.g. glass reinforced plastics material.

Problems can be encountered when using reinforcing layers of steel mesh: damage to the mesh during use (for example, due to sharp objects penetrating the mesh) may create sharp ends which cut their way out of the belt material, thus damaging the belt(s). Accordingly, in a further embodiment of the invention, said reinforcing means comprises one or more tensile cords extending longitudinally in the belts. The cords may be of rubber pre-coated textile material, which is preferably rubber coated kevlark The cords may be moulded in the belts. The or each cord may be looped round said connecting portion of said rod which extends through said apertures, so as to pass back and forth along the length of the belts.Alternatively, or additionally, the or each cord may be disposed so as to extend at least partially around each of said plurality of rods mounted across said belts.

In one embodiment, the ends of said cord or cords may be captively secured to, or anchored in, said reinforcing member means secured to the belt ends.

Various polymeric materials may be used in the belt including rubber and polyurethane. Curing may be carried out in any suitable manner known in the art such as baking at a temperature not less than the curing temperature of the polymeric material for a sufficient period of time.

Further preferred features and advantages of the present invention will appear from the following detailed description given by way of example of some preferred embodiments illustrated with reference to the accompanying drawings in which: Fig. 1 is a general perspective view of part of a conventional open web; Fig. 2 is a plan view of part of our earlier design of an open web; Fig. 3a is a detail cross-sectional side elevation of a connecting arrangement of the web of Fig. 2; Fig. 3k is a detail perspective exploded view of an alternative connecting arrangement for the web of Fig. 2; Fig. 4 is a partial plan view of a belt connecting means of the present invention; and Fig. 5 is a sectional elevation of the belt connecting means of Fig. 4.

Fig. 6 is a partial plan view of a modified embodiment of the belt connecting means of Figures 4 and 5; Fig. 7 is a sectional side elevation of the belt connecting means of Figure 6; Fig. 8 is a partial plan view of a further modified embodiment of the belt connecting means; Fig. 9 is a sectional side view of the belt connecting means of Figure 8; Fig. 10a is a plan view of a connecting member of the belt connecting means of Figures 8 and 9; Fig. lOb is a side view of the member of Figure 10a; Fig. lOc is an end view of the member of Figure 10; Fig. 11 is a partial plan view of an alternative belt connecting means of the present invention; Fig. 12 is a sectional side elevation of the belt connecting means of Figure 11; Fig. 13 is a partial plan view of a modified embodiment of the belt connecting means of Figures 11 and 12;; Fig. 14 is a sectional side view of the belt connecting means of Figure 13; and Fig. 15 is a partial plan view of a further embodiment of the belt connecting means of the present invention.

Fig. 2 shows an open web 10 suitable for use in a potato harvester (not shown) comprising two elongate belts 11 extending parallel to each other and a large plurality of rods 12 mounted in regular parallel spaced apart relation.

Opposite end portions 13 of the rods 12 are embedded inside respective ones of the two elongate belts 11 which are made of polyurethane and reinforced with three polyamide webbing tapes 14. As shown in the detail view, the end faces 12a of the rods 12 are set back slightly from the outer sides 11a of the belts 11 so that the end portions 13 of the rods are fully enclosed thereby minimizing the risk of damage to crops or to the machinery from sharp corners and edges on the ends of the rods. In order to reduce the risk of damage to the belts 11, these may also conveniently have included therein a steel mesh layer 19 or the like just below the outer face 20 of the belt 11 in order to provide a barrier to sharp-edged stones or the like cutting into the belt 11.

As illustrated in the alternative possible arrangements of Figs. 3a and 3b, at each end 15 of the belts 11 are used rods 16 which have hinge lugs 17 secured thereto which are secured together with a connecting rod 18 similar to the other rods 12, 16, thereby to join the ends of the belts 11 and thereby the open web, together.

In accordance with one preferred embodiment of the present invention the belt connecting means 17, 18 of the open web of Figs. 2-3 is replaced by a belt connecting means 21 as shown in Figs. 4-5. In more detail, one belt end 22 has a male, generally dovetail form, portion 23 and another belt end 24 has a substantially complementary female portion 25 defined by two half-dovetail sections 26 at either side thereof.

The side and end faces of the male and female portions 23, 25 are encased in metal, e.g. steel, sections 27, 28 extending generally perpendicularly to the plane of the belt 11. These metal sections help to rigidify the male and female portions 23, 25 and provide a positive interlocking of the belt ends 22, 24 longitudinally of the belts 11 whilst facilitating engagement and disengagement thereof by transverse displacement perpendicularly to the plane of the belt 11 thereat. In addition the metal sections 27, 28 help to hold captive therein distal end pieces 29, 30 of the flexible belt material against disengagement longitudinally of the belts, of the metal sections 27, 28 and the belt end pieces 29, 30.In order to help reduce this possibility further, the end pieces are locally "hardened" or "rigidified" by incorporation thereinto, in the belt moulding or other production process, of suitable. material e.g. chopped fibres 31, conveniently of Kevlarl(Trade Name) (only some shown).

The male and female portions 23, 25 are conveniently held together against disengagement by means of a "retaining" rod 32 generally similar to the other rods 12 of the open web albeit slightly longer in order to extend fully through transverse bores 33 provided in the half-dovetail sections 26 defining the female dovetail portion 25 as well as through the male dovetail.

In order further to reduce the possibility of breakage or separation of the belt at the male and female portions 23, 25, the textile webbing reinforcement 14 and/or the protective steel mesh layer 19 are desirably tied-in to the dovetail sections 23, 26 conveniently by means of enlarged head portions 34 as shown in Fig. 4. It will be appreciated that with the mechanical interlocking between the male and female portions 23, 25 little or none of the loading in the belt 11 is transferred to the retaining rod 32.

Nevertheless, if desired, one or other of the steel mesh layer 19 and textile webbing reinforcement may be provided with loop means 35 disposed so as to extend around the bores through which the retaining rod 32 extends thereby providing a degree of anchoring of the belt ends 22, 24 to the retaining rod 32.

As may be seen in the drawings a feature of the present invention, is that, unlike in the prior art, the belt connecting means can have a substantially limited extent longitudinally of the belt 11 so that any reduction in flexibility in the belt between the retaining rod 32 and neighbouring rods 12, relative to that between successive rods 12 in other parts of the belt is substantially limited thereby providing a more uniform bending performance in the belt along its full length, thereby improving operation and reducing the possibility of failure of the belt at the ends.

A modified embodiment of the belt connecting means 21 is shown in Figures 6 and 7. The belt 11 has two ends 22, 24 having complementary male and female portions 23, 25 of similar dovetail and two half dove-tail form as with the embodiment of Figures 4 and 5. The side and end faces of the male and female portions 23, 25 are similarly encased in sections 27, 28 of metal or rigid plastics material.

Additional appendages 40, 42 of the metal or plastics casings extend from an inner face of each section 27, 28 of the casings deep into the respective male and female portions 23, 25 to further rigidify the belt ends. However, in this embodiment the webbing tapes 14 and steel mesh 19 are replaced by one or more reinforcing cords 44 of tensile

material (e.g. kevlarn which have been pre-coated with a rubber material and which pass back and forth along the length of the belt 11. Two of the connecting portions 13 of the rods 12 are embedded in respective ones of the belt ends 22, 24 where they extend through apertures 27a, 28a provided in the belt ends and the casing sections 27, 28, the apertures being disposed clear of the dovetail and half dovetail portions of the belt ends.The cord or cords 44 moulded in the belt 11 is/are disposed so as to loop round the connecting portion at each end 22, 24 of the belt 11, the cord or cords being thus passed back and forth along the length of the belt, and each end of the cord or cords being looped around one of said two connecting portions and secured to itself. In this arrangement, loading in the belt is maintained largely in the tensile cord(s) 44 by means of the connection between the tensile cord in the belt ends via the said two portions of the rods, these two connecting portions being connected by means of the casing sections 27, 28 of the male and female end portions.

A locating pin 46 extends through apertures provided in the casing sections 27, 28 and the male and female portions so as to prevent the male and female portions from transverse disengaging movement, perpendicular to the plane of the belt. However, as in the embodiment of Figures 4 and 5, little or none of the loading in the belt is transferred to the locating pin 46.

Another modified embodiment of the belt connecting means 21 is shown in Figures 8, 9 and 10 (a), (b), (c). In this embodiment a metal or rigid plastics connecting member 50, 52 is moulded into each of the belt ends 22, 24 to reinforce the male and female portions 23, 25 of the belt ends. The connecting members 50, 52 extend across the width of the belt. A portion 51 of generally tapered end cross section of each member is embedded within the respective belt end, the base and an upper tapered surface of these portions each being covered by a layer 53, 55 of the material of the belt.

A portion of generally rectangular side cross-section of each of the connecting members 50, 52 protrudes beyond the belt ends to form the dovetail and half dovetails profiles of the male and female portions 23, 25. These protruding portions are provided with apertures 56 for receiving one of the connecting portions of the rods 12 extending across the belts.

As in the embodiment of Figures 6 and 7, reinforcing cords 54 and moulded in the belt 11 extend longitudinally through the belt. However, in this embodiment the cords 44 do not loop back and forth along the length of the belt. Instead, there is provided a series of bores 58 drilled in each of the metal or plastic members 50, 52 and one end of each cord is threaded through a respective bore in a respective one of the end members 50, 52. The bores 58 are disposed such that the ends of the cords 54 extend into the dovetail and half dovetail portions of the male and female portions of the belt ends, respectively. The ends of the cords are each anchored in a widened mouth of a respective bore 58, by means of a pin to which the cord is secured, or by means of a head swaged on to the cord.As illustrated in Figure 9, the belt 11 has a generally toothed profile with the connecting portions 13 of the rods 12 being located in raised and toothed portions 60 of the belt 11. The cords 44 extend longitudinally through the belt, below the rods 12.

The bores 58 in the moulded-in connecting members 50, 52 are arranged alternately either parallel or at an angle to the plane of the belt, in each of the dovetail and half dovetail portions of the male and female portions, as illustrated by Figures 10 (a), (b) and (c) which show plan side and end views respectively of the member 50 which is embedded in the belt end having the male portion (not shown).

In accordance with an alternative preferred embodiment of the present invention the belt connecting means 17, 18 of the open web of Figs. 2-3 is replaced by a belt connecting means 61 as shown in Figs. 11-12 in which like parts in Figs. 11-12 and Figs. 2-3 are referenced using the same numerals. In more detail, one belt end 22 has a male portion 23 and another belt ends 24 has a similar male portion 63. A steel connecting member 65 of generally I-or H- shaped cross-section is located between the two male portions 23, 63, the steel member 65 defining two female portions 66, 67 for coupling to respective ones of said male portions 23, 63 and the width of the steel members being not greater than the width of the belt.One of said male portions 23 and a respective one of said female portions 66 of said steel member 65 are conveniently held together against disengagement by means of a connecting portion 13a of a rod 68, generally similar, and parallel, to the other rods 12 of the open web, which extends through an aperture defined by a bush 70 which is embedded in a protruding head portion of the male portion 23. The other one 63 of the male portions and the other respective one 67 of the female portions of the steel member 65 are also conveniently held together against disengagement by means of a connecting portion 13b of another rod 72, generally similar, and parallel, to the rods 12 of the open web, which extends through a similar bush 74 embedded in a similar protruding portion of the other male portion 63.Each one of the connecting portions of the rods 68, 72 which connect the male and female portions is held in place by means of a retaining pin 71 which extends through the steel member 65, or an O 'ring' located in the steel member 65, which engages with a recess 73 provided in the connecting portion of the respective rod. The bushes 70, 74 enable the belt ends 22, 24 to pivot relative to the steel member 65. A cover plate 75 is secured to an upper portion of the steel member 65 trapped between the male belt portions and the steel member 65.

The connecting means 61 is contained within the width of the belt, the female portions captively engaging the male portions against relative movement of the male and female portions transversely of the belt, in a direction parallel to the plane of the belt.

A tensile reinforcing cord or cords 76 are moulded into the belt 11 and extend longitudinally in the belt, the cord or cords 76 being looped round the bushes 70, 74 at each end of the belt so as to pass back and forth along the length of the belt. The ends of the cords are secured onto themselves around the bushes 70, 74. Loading in the belt 11 is largely maintained in the belt by means of the connection of the tensile cords in each belt end 22, 24 by the connecting portions 13a, 13k of the rods and the steel connecting member 65.

Figures 13 and 14 show a modified embodiment of the belt connecting means of Figures 11 and 12 in which the belt 11 is of generally undulating profile on both its upper and lower surfaces and wherein the cord or cords 76 extend(s) at least partially round each of the connecting portions of the rods 12 as well as looping round the bushes 70, 74 through which the connecting portions of the connecting rods 68, 72 extend.

Figure 15 shows a further embodiment of the invention in which one end 22 of the belt 11 has a male portion 23 and the other end 24 of the belt has a complementary female portion 25. Transverse passage means are provided by apertures in the male and female ends for receiving a connecting portion 80 of one of the rods 12 extending across the belts. A reinforcing tensile cord or cords 82 are moulded in the belt 11 and loop around the connecting portion of the rod so as to pass back and forth along the length of the belt. The male and female portions are provided within the width of the belt itself and are pivotable about the connecting portion 80 of the rod extending through the apertures. There may be provided one or more washers or O-rings 82 located on the connecting portion of the rod and between the male and female portions of the belt ends.

Whilst open webs of the invention will normally be made in one piece with only one belt connecting means in each belt, it will be appreciated that two or more sections may be connected together to provide longer open webs. In such cases opposite ends of each belt will usually be of opposite gender but if desired there could be used, for example, one belt with male formations at each end, with another belt with female formulations at each end etc.

It will be appreciated that various modifications may be made to the abovedescribed open web without departing from the scope of the present invention. Thus for example the belts may be provided with teeth for engagement with drive sprockets thereby avoiding the use of drive transmission to the open web via the rods and thus reducing loading on the interface between the rod ends and the belts. Also it will be appreciated that each belt end may have a plurality of male/female portions formed therein across the width of the belt.

Claims

1. An open web (10) suitable for use in conveying and separating bodies such as root crops and stones and clods, which web comprises at least two elongate belts (11) extending parallel to each other in substantially spaced apart relation, and a plurality of rods (12, 68, 72) mounted in parallel spaced apart relation across said belts with connecting portions (13, 13a, 13b) of said rods substantially embedded within the body of said belts, said elongate belts having longitudinally extending therethrough tensile reinforcing means (14, 19, 44, 54, 76, 82) and having end members (22, 24) formed and arranged for connecting together with respective end members of the same or further said belts for forming respective endless elongate belts extending parallel to each other, characterised in that said end members have respective ones of substantially male and female portions (23, 25, 63, 66, 67) formed within the width of said belts, said male portions (23, 63) having head members for captive retention within said complementary female portions (25, 66, 67) transversely of the belts, in the plane of the respective endless belt thereat, said end members having captively interengaging connector means (23, 25, 27, 28, 50, 52, 65, 68, 72, 80) to which said tensile reinforcing means are captively connected.

2. An open web according to claim 1, wherein the connector means comprises a said connecting portion (13, 13a, 13b) of a said rod (12, 68, 72) extending through respective apertures in said male and female portions (23, 25, 63, 66, 67).

3. An open web according to claim 2, wherein said male and female portions are provided with reinforcing member means (27, 28, 50, 52, 65, 70, 74) secured to the belt ends (22, 24), in which reinforcing member means said apertures are formed.

4. An open web according to claim 3, wherein said reinforcing member means comprises stiffening means (27, 28) having portions (40, 42) disposed internally of a belt end (22, 24) in which said male or female portion (23, 25) is defined.

5. An open web according to claim 3 or claim 4, wherein said reinforcing member means comprises stiffening means (27, 28) having portions disposed externally of a belt end in which said male or female portion is defined.

6. An open web according to claim 3 wherein said tensile reinforcing means (44, 54) are captively secured to said reinforcing member means (50, 52, 70, 74).

7. An open web according to any one of claims 3 to 6, wherein one belt end (22) is provided with a composite reinforcing member means comprising a separate connecting member (65) having a male or female portion at a distal end of the connecting member for connection to the female or male portion respectively of another belt end (24), a proximal end of the connecting member (65) having a male or female portion connected to a female or male portion respectively of said one belt end (22).

8. An open web according to any preceding claim wherein said end members (22, 24) and said connector means (68, 72, 65, 80) are formed and arranged so as to enable said male and female portions to relatively pivot.

9. An open web according to claim 8, as dependant from claim 2, wherein said rod connecting portion (13a, 13b) extends through part of the belt (11) itself, the belt being provided with a bush (70, 74) which is secured within the belt and defines an aperture therein in which aperture said rod connecting portion is received.

10. An open web according to claim 1, wherein the connector means comprises said male portion (23) having an enlarged head portion extending from a narrower neck portion, whereby said head portion is captively retained, longitudinally of the belt, in said complementary female portion (25).

11. An open web according to claim 10, wherein said male portion (23) is of substantially dovetail form and said complementary female portion (25) comprises opposed portions of substantially half dovetail form.

12. An open web according to claim 10 or claim 11 further comprising a retaining pin (12, 46) for preventing disengagement of the male and female portions by relative movement perpendicular to the principal plane of the respective endless elongate belt.

13. An open web according to any of claims 10 to 12, wherein said reinforcing member means comprises reinforcing members (50, 52) secured to the belt ends (22, 24) in which reinforcing members said male and female portions (23, 25) are formed.

14. An open web according to any of claims 10 to 13, wherein said connector means further comprises two of said connecting portions (13) of said rods (12), each connecting portion extending through apertures (27a, 28a) in a respective one of said male and female portions (23, 25), to which two connecting portions said tensile reinforcing means (44) are captively connected.

15. An open web (10) suitable for use in conveying and separating bodies such as root crops and stones and clods, which web comprises at least two elongate belts (11) extending parallel to each other in substantially spaced apart relation, and a plurality of rods (12) mounted in parallel spaced apart relation across said belts with connecting portions (13) of said rods substantially embedded within the body of said belts and secured thereto by bonding of said belts to said connecting portions, said elongate belts having end portions (22, 24) formed and arranged for connecting together with respective end portions of the same or further said belts for forming respective endless elongate belts extending parallel to each other, characterized in that said end portions (22, 24) have respective ones of substantially complementary male and female portions (23, 25), said male portions having substantially enlarged heads for captive retention within said complementary female portions longitudinally of the belts, said male and female portions having transversely extending passage means for receiving therethrough retaining rod means (32) extending across said belts parallel to said plurality of rods, for captive retention of said male and female portions against transverse disengagement.

16. An open web according to claim 15, wherein said male and female portions (23, 25) are each provided with external reinforcing member means comprising a casing (27, 28) of a metal or substantially rigid plastics material.

17. An open web according to any preceding claim, wherein a generally flexible material of the belt (11) is locally reinforced at the male and female portions (23, 25) of the end members by incorporation of chopped fibres.

18. An open web according to any preceding claim, wherein said belts (11) have included therein reinforcing means comprising one or more reinforcing layers (14) of woven textile material and/or steel mesh (19).

19. An open web according to claim 18, wherein said one or more layers (14) of textile material are pre-coated with a rubber material prior to inclusion in said belts.

20. An open web according to any preceding claims, wherein said belts have included therein reinforcing means comprising one or more tensile cords (44, 54, 76, 82) extending longitudinally in the belts.

21. An open web according to claim 20, wherein said one or more tensile cords (44, 54, 76, 82) are rubber pre-coated textile cords which are moulded in the belts.

22. An open web according to claim 20 or claim 21, as dependant from claim 2, wherein the or each tensile cord is looped round said rod connecting portion (13, 13a, 13b) which extends through said apertures in said male and female portions (23, 25, 63, 66, 67) and the or each cord passes back and forth along the length of the belts.

23. An open web according to claim 20 or claim 21, as dependant from claim 7, wherein the or each tensile cord (76) is looped round two rod connecting portions (13a, 13b) which connect said separate connecting member (65) to the belt ends (22, 24).

24. An open web according to claim 20 or claim 21, as dependant from claim 13, wherein opposite ends of each one of a plurality of such tensile cords (54) are secured to respective ones of said reinforcing members (50, 52) in the belt ends (22, 24).

25. An open web according to claim 20 or claim 21, as dependant from claim 14, wherein the or each tensile cord is looped round said two rod connecting portions (13).