WO2005049454A2

WO2005049454A2 - Improvements relating to belts

Info

Publication number: WO2005049454A2
Application number: PCT/GB2004/004829
Authority: WO
Inventors: Hugh Sharkey
Original assignee: Duromould Limited
Priority date: 2003-11-14
Filing date: 2004-11-15
Publication date: 2005-06-02
Also published as: WO2005049454A3; GB2423293B; GB0326595D0; GB0611766D0; GB2423293A

Abstract

An open web conveyor comprising a pair of endless belts formed from belt pieces (20) having at least one aperture (36) for securing the belt to a connector, each belt piece having a tensile reinforcement cord (38) extending substantially longitudinally therethrough, continuously between the ends of the belt piece and around the one or more apertures therein, the position of the one or more apertures within the ends of the belt piece and the location of the cord within the belt piece being such that the resultant force acting on the or each aperture due to tension applied to the reinforcing means during use of the belt piece acts in a substantially radial direction with respect to the axis of said the or each aperture, whereby there is substantially no resultant turning moment about the or each aperture.

Description

Improvements relating to belts

The present invention relates to belts and belt pieces for use with open webs.

Open webs of the type often referred to as continental webs are widely used in agricultural machinery for conveying, sorting and cleaning root crops and other farm produce, stone and clod separation, etc. The web generally comprises a plurality of rods or bars, generally steel, mounted in parallel spaced apart relation across two or more parallel spaced apart belts. The rods are sometimes inter-linked so as to form squares, hexagons or circles, etc. of a required size such as for use as a potato grader.

The belts are generally rubber traction belts designed to support the rods, but also to provide a means for driving the web using rollers at the edge of the agriculture machinery. Robust web construction is naturally desired, not only because of the active nature of the use of the web, but also the general rough handling expected with agricultural machinery. Meanwhile, the commonest method of forming belts is to cut suitable lengths of belt material from a continuous belt manufacturing process, add clamp pieces to each end, and clamp the two ends together to form a continuous belt loop. The rods or bars can then be riveted through the belt material and into clamping plates underneath the belt, so as to secure the rods to the belt.

This form of construction has several benefits. The simple riveting connection enable rods to be replaced without need for special tools. This arrangement is relatively cost effective, as no expensive materials are required. Standard engineering shop equipment can be used to make the construction process cheap, and the final web is generally sufficiently robust for many uses, and has an adequate life span if properly maintained.

However, the weakness in such webs is the clamping together of the two ends to form the continuous belts. Whilst the clamp pieces are generally riveted to the belt ends, the joining system is usually a poor quality and unsuitable for heavily loaded applications. It is also inflexible and inaccurate on sprocket drives which leads to premature failure of such belts. It is usually the clamp which breaks for such belts, and then rejoining the belt either by repairing the clamps or adding new clamps requires a separate workshop.

Moreover, there is no flexibility between the belt and clamps, which, especially for closer pitched webs, provides a definite point of weakness, and hence likely breakage.

GB 2,290,515 discloses, in Figures 6 and 7, an open web conveyor comprises spaced parallel belts having elongate rods mounted therebetween, each belt being reinforced with one or more thin reinforcing cords of tensile material passing back and forth along the length of the belt . The cord or cords moulded within each belt are disposed so as to loop around the connecting portions and around through apertures provided therein. The location of the cord or cords within the belt (i.e. adjacent the lower surface of the belt) and the position of the connection apertures are such when tension is applied to the cords during use of the belt, such tension creates a resultant force acting substantially tangentially to the apertures around which the cords pass. Such resultant force creates a turning moment around the central axis of said aperture which is resisted by the dovetail connection and this leads to uneven stresses and stress concentrations in the cords which leads to early failure thereof. The thin cords also fret against the rod causing premature failure. Furthermore, the action of stones against the belt causes internal weakness within the thin diameter cords. It is an object of the present invention to provide an improved belt for open webs .

According to the present invention there is provided a belt piece having a main body and a connection portion at each end thereof, each connection portion including at least one aperture therethrough for receiving an elongate member defining or forming part of a connection means to permit the connection portions of the belt piece to be interconnected to form an endless belt for use in an open web conveyor, the belt piece being provided with tensile reinforcement means comprising one or more cables or cords extending substantially longitudinally through the main body of the belt piece, continuously between the connection portions and around the one or more apertures of each connecting portion, the position of the one or more apertures within the connection portions and the location of the reinforcement means within the belt piece being such that the resultant force acting on the or each aperture of each connection portion due to tension applied to the reinforcing means during use of the belt piece acts in a substantially radial direction with respect to the axis of said the or each aperture, whereby there is substantially no resultant turning moment about the or each aperture.

Preferably the rein orcement means extends a plurality of times between the connection portions and around each one or more aperture therein. The reinforcement means may encir-cle the or each aperture in each connection portion one or more times before returning to the main body of the belt piece.

The connection portions can h>e brought and connected together either directly, or indirectly using an intermediate connection means such as a clip, joining piece or the like.

The conjunction of the connecting portions, or the connecting portions and the connection means, is preferably flexible in the general direction of belt travel .

In one embodiment the aperture of each connection portion extends transversely to the length of the belt piece in a plane parallel to the surface of the belt piece. The connection means and connection portions may be conjoined by co-journalled rods or bars, such as the rods or bars of the complete web. The aperture of each connection portion is preferably adapted to receive or house an end of one of said rods or bars.

In an alternative embodiment the at least one aperture of each connection portion extends perpendicular to the surface of the belt piece. Preferably each connection portion is provided with a plurality of parallel apertures arranged at spaced locations across the width of the belt piece. Each connection means may be securable to a joining piece by means of fasteners , such as one or more bolts , screws , rivets or the like, passing through said one or more apertures in each connection portion of the belt piece .

The reinforcement means may encircle the or each aperture in each connection portion one or more times before returning to the main body of the belt piece.

The or each aperture in each connection portion may be reinforced by a bush or ferrule contained therein.

The main body of the belt piece may be formed of any suitable material known in the art, such material generally being a flexible material involving rubber and/or plastics, or a combination or a plurality of same.

Preferably, the connection portions and main body of the belt piece are formed integrally. The belt piece could be formed by any suitable means, including moulding. Moulding provides the ability for the adaptation of the belt to be secured to rods to be integrally formed or shaped therefor. For example, rod rivet holes could be formed integrally in the mould, as well as the locations for rod clamping plates.

The reinforcement means may be formed using any suitable material, preferably a metal or plastic material or combination, such as steel or a polyester. The reinforcement means is preferably wholly or substantially circular in cross section rather than the flat or sheet-like reinforcement layers added to other types of belts. Such circular reinforcement can occupy less space, and hence make the belt thinner, and hence more flexible especially, the ends of the belts . This flexibility is essential as conventional belts frequently break just behind their (inflexible) joining ends. Preferably the reinforcement means comprises one or more cords or cables having a diameter of at least 5mm.

The present invention extends to the belt piece being formed into an endless belt for use with an open web, and an open web having one or more endless belts formed from belt pieces as hereinbefore defined.

According to a further aspect of the present invention there is provided a method of manufacturing a belt piece as herein defined, comprising the steps of providing- an elongate through belt mould; introducing fluid uncured mouldable material into the mould.; adding into the mould, either prior to or after introducing the fluid material, one or more elongate tensile reinforcement means comprising one or more cables or cords which extend substantially longitudinally at least from the main body to each connection portion of the mould; placing formations to form one ore more apertures in each connection portion within the mould; curing the material so as to form an elongate belt piece in which is embedded the or each tensile reinforcement means and in which, is integrally formed one or more apertures, such that the reinforcement means is protected, from the environment surrounding the thus produced belt piece when in use.

Preferably rivet holes for securing rods to the belt piece are integrally moulded within the belt piece.

An embodiment of the present invention will now be described of example only, and with reference to the accompanying drawings in which;

Figure 1 is a plan view of a potato grader web;

Figures 2a and 2b are partial plan views of a prior art belt and its clamping arrangement ;

Figure 3 is a two-part plan view of the ends of a belt piece according to a first embodiment of the present invention;

Figure 4 is a cross section along line X-X in Figure 3;

Figure 5 is a side view of Figure 3;

Figure 6 is a cross sectional view along the line Y- Y in Figure 5; Figure 7 is a side view of a ferrule cap which can be fitted around the connection portions to increase wear resistance;

Figure 8 is an end view of the ferrule cap of Figure 7;

Figure 9 is a two-part plan view of the ends of a belt piece according to a second embodiment of the present invention;

Figure 10 is a cross section along line X-X in Figure 9;

Figure 11 is a side view of the belt piece of Figure 9;

Figure 12 is a cross section along line Y-Y in Figure 11;

Figure 13 is a plan view of a belt piece according to a third embodiment of the present invention;

Figure 14 is a side view of Figure 13;

Figure 15 is a cross section along line X-X in Figure 13;

Figure 16 is a two-part plan view of the ends of a belt piece according to a fourth embodiment of the present invention; Figure 17 is a cross section on line X-X of Figure 16;

Figure 18 is a side view of the belt piece of Figure 16;

Figure 19 is a cross section on line Y-Υ of Figure 18;

Figure 20 is a plan view of the ends of a belt piece according to a fifth embodiment of the present invention;

Figure 21 is a cross section on line X-_X of Figure 20; and

Figure 22 is a side view of the belt piece of Figure 20.

Referring to the drawings, Figure 1 shows a known potato grader web suitable for use in a potato grader (not shown) . It comprises a number of link pieces 2 supported on a plurality of perpendicular supporting rods 4 mounted in regular parallel spaced apart relation. Opposite ends of the rods 4 are supported by two rubber traction belts 6. The link pieces 2 form squares of desired shape and size, and the supporting rods 4 keep the link pieces 2 together, whilst still providing flexibility of the lines of link pieces 2 as is required. Figure 2a shows part of the rods 4 and ends of the belt 6 in a form common in the art, used for example on a potato harvester or stone separator. The belt 6 is formed from a length of belt material, the ends of which have complementary clamp pieces 8 which are riveted to the belt material by four rivets 10, overlapping the last rod on each side 4a. Similar rivets 10 are used to rivet the other rods 4 to the belt 6. The clamp pieces 8 are brought together and share a common rod 4b to effect the forming of a continuous belt 6.

However, the clamp so-formed is only as strong as the rivets 10, and whilst the breaking of a rivet 10 which holds on each of the other rods 4 only leads to simple repair of that rod 4, breakage of the closer rivets 10 holding on the clamp pieces 8 leads to disuniting of the belt ends, and thus complete breakage of the whole web. Moreover this elongated clamp makes the joint inflexible, adding increased stress to belts between first and. second rods 4a, 4, causing breakage.

Another common failure is when the rivets 10 do not break but the clamp piece 8 is simply 'pulled off the end of the belt 6. This is shown in Figure 2b. This causes the belt 6 to be shortened during repair and renders it useless.

Figure 3 shows a plan view of two ends of a belt piece 20 according to a first embodiment of the present invention. The belt piece has a main body 22 and a connecting portion 24 at each end.

Attached to the main body 22 are rods 26. The rods 26 are generally rounded in section, but flattened at connection portions 28 which are provided with holes. Through the holes extend rivets 30 which pass through the main body 22 of the belt piece 20 and clamping plates 34 to secure the rods 26 to the belt 20.

Figure 4 shows a cross section through Figure 3, showing each connection portion 24 of the belt piece 20 having a transverse aperture 36 as a connecting means therethrough. This is also shown in Figure 5. Figure 4 also shows the belt piece 20 including a 6mm diameter twisted polyester cord 38 which extends around each connection portion 24 and continuously through the main body 22.

As shown in Figure 6, the cord 38 is a single cable which runs continuously along the belt piece 20 and around each connection portion end 24 several times, and which is terminated in the body of the belt piece 20. The use of the cord 38 or similar cable reduces the necessary thickness of the belt piece 20, a critical factor related to flexibility. The thinner the belt piece 20, the greater flexibility, reducing the problem concerning rubber thickness which can be susceptible to flex cracking, along the length of the belt, but critically at or near the ends. This is more important in closer pitch webs where there is less room between the joint and first rivet rod.

By running the cord 38 around the aperture 36 through each connection portion 24, increased strength and reinforcement is provided to each connection portion 24 through the main body 22, and indeed to the opposite connection portion 24.

As can be seen in Figure 4, the cord 38 is substantially aligned with the central axis of the aperture 26 such that tension forces applied to the cord 38 are transmitted to the connection portion through the centre of the aperture whereby there is substantially no resultant turning moment about the aperture resulting in an equal force distribution throughout the cord 38 and no fretting of the cord.

Figures 3, 4 and 5 show a joining clip 44 as a means for connecting the connection portions 24. The joining clip 44 comprises a central body 46 and wings 48 extending from each side. Each wing 48 is journalled to have complementary apertures to that of the connecting portions 24, such that a rod (not shown) , similar to those used elsewhere in the grader web but not having flattened ends, could be introduced through the apertures in the wings 48 and the connecting portions 24 to create the connection, and also to serve as part of the complete web.

The result is a joint which is quickly replaceable, and as strong as the belt piece 20 itself . The flexibility of the joint, providing separate rotation about the rod to the clip 44 and connection portions 24, provides increased flexibility of the complete joint compared with that shown in Figure 2, reducing the stress on the completed continuous belt, especially between the closest rods to the joint, which is a common source of belt breakage in conventional webs, as shown in Figure 2b.

Figure 6 shows the rivets 30 through the flattened ends 28 of the rods 26, the main body 22 of the belt piece 20, and the clamp pieces 34. The holes for the rivets 30 could be formed in a moulded belt piece 20, such that the reinforcing cable 38 deliberately passes around the holes. This results in no reduction in the tensile strength of the belt 20 despite the existence of the rivet apertures. All the slots for the clamping plates 34 can also be moulded with the belt piece 20, giving very accurate pitching of the position of the rods 26.

Figures 7 and 8 show front and side views of a ferrule cap 50 which can be fitted around the connection portions 24 to increase wear resistance, or fitted or moulded into the connections portions 24 also.

Dimensions shown in the drawings are for illustration purposes only, and are not limiting.

The belt piece 20 of the present invention can be lengthened by the easy addition of further belt pieces, possibly of different lengths, using the simple joining clips 44. The joining system is as strong as the belt, and as flexible as well. The joining clips 44 can be made from heavy plate metal which adds to the service of the belt piece 20.

The second through fifth embodiments shown in Figures 9 to 22 differ from the first embodiment shown in Figures 3 to 8 in that the apertures 36 in the connection portions 24 of the belt piece 20, ty means of which the belt piece 20 is secured to a connection means and around which the tensile reinforcement cord 38 is looped, extend perpendicularly to the surface of the belt piece 20. This enables the cord 38 to be more easily aligned! with the central axis of the apertures 36 in the connection portions 24, thus balancing the stress on each section of cord 38 extending between the connection portions 24. In each of the second to fifth embodiments, the single cord 38 passes back and forth through the main body 22 of the belt piece 20 between the connection portions 24 and is wound around each aperture 36 in the end portions 24 of the belt piece 20 one ore more times, preferably twice, before returning to the main body 22 to maximise the strength of the joint between the connection portions 22 when the connection portions 22 of the belt piece 20 are connected together to form an endless belt.

Figures 9 to 12, show a belt piece according to a second embodiment of the invention, wherein a tensile reinforcement cord 28 extends backwards and forwards through the main body 22 of the belt piece 20 and the connection portions 24 thereof, the cord looping around apertures provided in the connection portions 24 of the belt piece, the apertures extending perpendicular to the surface of the belt piece 20.

Rods 26 are connected to the main body 22 of the belt piece 20 and are identical to those shown in the first embodiment. The rods 26 are generally rounded in section, but flattened at connection portions 28 which are provided with holes. Through the holes extend rivets 30 which pass through the main body 22 of the belt piece 20 and clamping plates 34 to secure the rods 26 to the belt 20. The rivets 30 pass between the sections of the cord 38 running though the main body 22 of the belt piece 20.

The connection means connecting the connection portions 24 of the belt piece 20 together comprises an upper plate 100 having a pair of rods 102 integrally formed therewith and extending therefrom to a mirror image plate for connection to connection portions of a belt piece on the opposite side of the open web and a corresponding pair of lower plates 104.

The rods 102 of the upper plate are similar in size and spacing to the rods 26 secured to the main body 22 of the belt piece 20. The upper plate 100 has a plurality of countersunk apertures 106 therethrough corresponding to the apertures 36 provided in the connection portions 24 of the belt piece 20. The corresponding lower plate 104 has threaded apertures 108 formed therein corresponding to the apertures 106 provided in the upper plate 100 and apertures 36 provided in the connection portions 24 of the belt piece 20. Threaded fasteners 110 are inserted through the respective apertures 106,36 in the upper plate 100 and end portions 24 of the belt piece 20 and are screwed into the threaded apertures 108 in the lower plate 104 to secure the connection portions 24 of the belt piece 20 together to form an endless belt.

As shown in Figures 9, 10 and 12, the cord 38 extends through the main body 22 of the belt piece 20 into one connection portion 24, is wrapped around an aperture 36 twice before returning to the main body 22 and then extending into the other connection portion 24 where it again is wrapped twice around an aperture 36 before returning to the main body and extending again to the first connection portion. Since there are three apertures 26 in each connection portion 24 this process occurs three times such that there are six portions of cord 38 extending longitudinally within the main body of the belt piece 20.

Figures 13 to 15 show a third embodiment of the invention, essentially identical to that of the second embodiment with the exception of the connection means for connecting the connection portions 24 of the belt piece 20.

A U-shaped clamp portion 200 is secured to each connection portion 24 in the same manner as the upper and lower connecting plates 100, 104 of the second embodiment using threaded fasteners extending through the apertures 36 in the connection portions 24. The clamp portions 200 provide a transverse aperture extending across the width of the belt piece by means of which a joining clip 204, comprising a central body 206 and wings 208 extending from each side, can be secured to the connection portions 24 of the belt piece 20. Each wing 208 is journalled to have a complementary aperture to that of the clamp portion 200, such that a rod 210, similar to those rods 26 attached to the belt piece but not having flattened ends, can be introduced through the apertures in the wings 208 and the clamp portions 200 to create the connection, and also to serve as part of the complete web. This connection means provides greater flexibility than that of the second embodiment .

Figures 16 to 19 show a fourth embodiment of the invention wherein the rods 26 are moulded into the main body 22 of the belt piece 20. In order to prevent the rods from being pulled out of the main body 22 of the belt piece 20, rod retainers 300, in the form of wire loops, are provided to secure the ends of each rod to the reinforcement cord 26 provided within the belt piece 20. The rod retainers are similar in construction and operation to those disclosed in EP 0937001 and this will not be described in more detail herein.

Figures 20 to 22 disclose a further embodiment of the invention, similar to that shown in the fourth embodiment but with a different connection means where more flexibility of the connection means is required.

The connection means 400 comprises a pair of complementary connection components 402, 404 connectable together in the manner of a hinge . Each connection component 402,404 comprises a substantially U-shaped clamp like member adapted to be fitted around a connection portion 24 of the belt piece 20 and having apertures corresponding to the apertures 36 provided in the connection portions 24 of the belt piece 20 by means of which each connection component 402,404 can be secured to a connection portion 24 of the belt piece 20 by means of threaded fasteners 110.

Each connection component 402,404 defines a transverse aperture therethrough, such that a rod 406, similar to the rods 26 attached to the belt piece 20, but not having flattened ends, can be introduced through the apertures in the connection components 402,404 to create a hinge like connection, and also to serve as part of the complete web. This connection means provides greater flexibility than that of the fourth embodiment .

The present invention provides a simple but effective way of significantly increasing the strength of a belt, so as to increase the robustness of the belt joint and increasing flexibility, whilst maintaining the easy means to repair broken rods, by using the riveting methods.

In each of the preferred embodiments, the belt piece is manufactured by moulding comprises the steps of placing the reinforcement cord 38 and other components within a mould and integrally moulding the connecting apertures 36 and other holes (e.g. rivet holes) such that the reinforcing cord 38 is sealed within the material of the belt piece and is protected from fluid which would otherwise lead to premature degradation of the reinforcement cord 38. The reinforcement cord 38 is effectively isolated from degrading liquids and the like.

Claims

Claims 1. A belt piece having a main body and a connection portion at each end thereof, each connection portion including at least one aperture therethrough for receiving an elongate member defining or forming part of a connection means to permit the connection portions of the belt piece to be interconnected to form an endless belt for use in an open web conveyor, the belt piece being provided with tensile reinforcement means comprising one or more cables or cords extending substantially longitudinally through the main body of the belt piece, continuously between the connection portions and around the one or more apertures of each connecting portion, the position of the one or more apertures within the connection portions and the location of the reinforcement means within the belt piece being such that the resultant force acting on the or each aperture of each connection portion due to tension applied to the reinforcing means during use of the belt piece acts in a substantially radial direction with respect to the axis of said the or each aperture, whereby there is substantially no resultant turning moment about the or each aperture.

2. A belt piece as claimed in claim 1, wherein the reinforcement means comprises a single cable or cord.

3. A belt piece as claimed in claim 1 or claim 2, wherein the reinforcement means extends a plurality of times between the connection portions and around each one or more aperture therein.

4. A belt piece as claimed in any preceding claim, wherein the reinforcement means encircles the or each aperture in each connection portion one or more times before returning to the main body of the belt piece.

5. A belt piece as claimed in any preceding claim, wherein the aperture of each connection portion extends transversely to the length of the belt piece in a plane parallel to the surface of the belt piece.

6. A belt piece as claimed in claim 5, wherein the connection means and connection portions are conjoined by co-journalled rods or bars, such as the rods or bars of the complete web, the aperture of each connection portion being adapted to receive or house an end of one of said rods or bars.

7. A belt piece as claimed in any of claims 1 to 4, wherein the at least one aperture of each connection portion extends perpendicular to the surface of the belt piece.

8. A belt piece as claimed in claim 7, wherein each connection portion is provided with a plurality of parallel apertures arranged at spaced locations across the width of the belt piece.

9. A belt piece as claimed in claim 7 or claim 8, wherein each connection means is securable to a joining piece by means of fasteners, such as one or more bolts, screws, rivets or the like, passing through said one or more apertures in each connection portion of the belt piece.

10. A belt piece as claimed in any preceding claim, wherein the or each aperture in each connection portion is reinforced by a bush or ferrule contained therein.

11. belt piece as claimed in any preceding claim, wherein, the connection portions and main body of the belt piece are formed integrally.

12. A belt piece as claimed in any preceding claim, wherein the reinforcement means is wholly or substantially circular in cross section.

13. A belt piece as claimed in claim 12, wherein the reinforcement means has a diameter of at least 5mm.

14. A method of manufacturing a belt piece as claimed in any preceding claim, comprising the steps of providing an elongate through belt mould; introducing fluid uncured mouldable material into the mould; adding into the mould, either prior to or after introducing the fluid material, one or more elongate tensile reinforcement means comprising one or more cables or cords which extend substantially longitudinally at least from the main body to each connection portion of the mould; placing formations to form one ore more apertures in each connection portion within the mould; curing the material so as to form an elongate belt piece in which is embedded the or each tensile reinforcement means and in which is integrally formed one or more apertures, such that the reinforcement means is protected from the environment surrounding the thus produced belt piece when in use.

15. A method of manufacture as claimed in claim 14, wherein rivet holes for securing rods to the belt piece are integrally moulded therein.

16. endless belt for use with an open web, said continuous belt being formed from a belt piece as claimed in any preceding claim.

17.An open web having one or more endless belts formed from belt pieces as claimed in any of claim 1 to 13.