GB2264685A

GB2264685A - Conveyor system with belts.

Info

Publication number: GB2264685A
Application number: GB9204806A
Authority: GB
Inventors: John Richard Ewen
Original assignee: Cable Belt Ltd
Current assignee: Cable Belt Ltd
Priority date: 1992-03-04
Filing date: 1992-03-04
Publication date: 1993-09-08
Also published as: ZA931506B; GB9204806D0; CA2090916A1; AU3370093A

Abstract

A conveyor system comprises a conveyor belt 10 supported and driven by engagement between an under surface of the belt with a pair of parallel spaced cables 15 extending longitudinally along the belt. The cables are driven to drive the conveyor belt and a feed chute 20 is mounted adjacent a loading end of the belt. Material is fed on to the belt through the feed chute and a pair of spaced side plates 21 are provided to define a channel therebetween for containing material loaded on to the belt. Each side plate has a lower edge adjacent to but spaced from the conveyor belt surface and the belt is provided with scrapers which pass through these gaps to scrape material from the lower edges of the side plates. This prevents the build-up of material between the lower edges of the side plates of the conveyor belt and so reduces belt wear and frictional loads. <IMAGE>

Description

CONVEYOR SYSTEMS AND CONVEYOR BELTS The invention relates to conveyor systems and conveyor belts and more particularly to conveyor systems in which a conveyor belt is supported and driven by engagement between an under surface of the belt and a pair of parallel spaced cables extending longitudinally along the conveyor belt. The cables are driven to drive the conveyor belt and a feed chute is mounted adjacent a loading end of the conveyor belt and includes a pair of spaced side plates defining a channel therebetween for containing loose material loaded on to the conveyor belt at the loading end.

The purpose of these side plates is to centralize and contain the volatile loose material on the belt without spillage until it becomes settled and moves forward at belt speed. The lower edges of these side plates are formed by adjustable strips of flexible rubber or hard synthetic material, to seal against material emission whilst minimizing damage to the belt by constant rubbing action.

In practice, the sealing strips can be mounted in one of two ways. In the first way, the strips press hard on the conveyor belt to prevent the passage of material between the belt and the strips. However, whilst an effective seal may be obtained, to prevent material spillage, it produces also high resultant wear rates to the sealing strips and to the conveyor belt, requiring frequent or continuous adjustment of the sealing strip position and causing damage to the conveyor belt which, in some cases, can require premature replacement of the belt. One cause of the high wear rate is the effect of particles of the contained material passing between the lower edges of the sealing strips and the conveyor belt, so increasing attrition. This can also increase significantly the power requirement to drive the conveyor.

The alternative way is to leave a small gap between the lower edges of the sealing strips and the conveyor belt.

This allows the majority of particles to be contained between the plates with only dust and other small particles passing through the gap. These particles can be contained by outer and more flexible secondary sealing arrangements.

This arrangement has, also, the problem that material builds up between the lower edges of the sealing strips and the conveyor belt causing high wear on the belt at the skirt plate paths, leading to belt damage.

According to a first aspect of the invention, there is provided a conveyor system comprising a conveyor belt supported and driven by engagement between an under surface thereof and a pair of parallel spaced cables extending longitudinally along the conveyor belt, the cables being driven to drive the conveyor belt, and a feed chute mounted adjacent a loading end of the conveyor belt and including a pair of spaced side plates defining a channel therebetween for containing loose material loaded on to the conveyor belt at the loading end, each side plate having a lower edge adjacent to but spaced from the conveyor belt surface, the conveyor belt being provided with at least two scrapers of limited length in the direction of the length of the belt which are spaced laterally of the width of the belt and which project from the surface of the belt, the scrapers moving with the belt and engaging intermittently respective lower edges of the side plates to release material adhering thereto.

According to a second aspect of the invention, there is provided a conveyor belt comprising upper and lower belt surfaces and formations adjacent each edge of the belt for receiving respective cables for supporting and driving the belt, the upper surface of the belt being provided with at least two scrapers of limited length in the direction of the length of the belt which are spaced laterally of the width of the belt and project from the surface of the belt.

The scrapers thus remove regularly material adhering to the lower edges of the plates and thus prevent the build-up of material which might cause attrition to the belt. The wear to the belt is thus reduced and there is no additional power requirement.

The following is a more detailed description of some embodiments of the invention, by way of example, reference being made to the accompanying drawings in which: Figure 1 is a cross-sectional view of a conveyor system, Figure 2 is a cross-sectional view of a belt of the conveyor system of Figure 1, showing a first form of scraper, Figure 3 is a partial side elevation of the conveyor belt of Figure 2 showing the length of the scraper, Figure 4 is a similar view to Figure 3 but showing a second form of scraper, Figure 5 is a similar view to Figure 3 but showing a third form of scraper, and Figure 6 is a similar view to Figure 3 but showing a fourth form of scraper.

Referring first to Figure 1, the conveyor system comprises an endless conveyor belt 10 of plastics or rubber material. The belt is arranged in a loop with upper and lower runs.

The belt 10 has an upper surface 11 provided with a pair of spaced longitudinally extending shoes adjacent respective lateral edges of the belt 10. The lower surface 13 has similar shoes 14 but spaced inwardly of the longitudinal edges.

A pair of side-by-side but spaced looped cables 15 are supported in respective upper runs on a first pair of spaced pulleys 16 and in a lower run on a second pair of spaced pulleys 17. The pulleys are rotatably mounted on a frame 18 and a number of such frames are provided at spaced intervals along the length of the conveyor belt 10.

In their upper runs, the cables engage the shoes 14 dn the lower surface 13 of the conveyor belt 10. In their lower runs, the cables 15 engage the shoes 12 on the upper surface 11 of the conveyor belt 10.

The cables 15 are driven by motors (not shown) and so perform the dual purpose of supporting and driving the conveyor belt 10. Such a system is well known and has the advantage that there is no direct engagement between the drive and the conveyor belt and that the conveyor belt 12 can trough between the cables 15 to accommodate a load of loose material 19.

The frame 18 shown in Figure 1 is a frame at a loading end of the conveyor. The frame supports a feed chute 20 through and by which loose material 19 is guided on to the upper surface 11 of the conveyor belt 10. The feed chute 20 terminates at its lower end in generally vertical side plates 21 which terminate at their lower edges adjacent the upper surface 11 of the belt 10. Each side plate 21 includes an elongate sealing strip 22 which projects downwardly below of the lower edge of the associated side plate 21, and is spaced from the upper surface 11 of the conveyor belt 10 by a small gap (not seen in Figure 1).

The sealing strips 22 may be carried on mountings 23 that allow the vertical position of the sealing strips 22 to be adjusted.

In use loose material 19 is fed down the feed chute 20 on to the moving conveyor belt 10. The loose material 19 is contained by the side plates 21 and the sealing strips 22 until it becomes settled and moves forward at belt speed.

Some material may pass through the gaps between the lower edges of the sealing strips 22 and the belt 10 and, if this is a substantial problem (as may be the case if the material is particularly dusty), further sealing strips (not shown) may be provided of very flexible material spaced laterally outwardly of the side plates 21.

As best seen in Figures 2 and 3, the belt 10 is provided with a plurality of pairs of laterally spaced scrapers 24. Each scraper 24 is in the form of a pad of flexible material, which may be the same material as the material of the upper surface 11 of the belt 10. Each scraper 24 may include a reinforcement 24a. As seen in Figure 2, the pads of each pair are in axial register and as seen in Figure 3, each pad is of limited length in the direction of the length of the conveyor belt 10. As also seen in Figure 2, each pad projects inwardly from the adjacent edge of the belt 10 towards the centre of the belt. The thickness of each pad is substantially the thickness of the gap between the lower edges of the sealing strips 22 and the adjacent upper surface 11 of the conveyor belt 10.

The scrapers 24 are positioned so that, as the conveyor belt 10 moves, they pass through the associated gaps between the sealing strips 22 and the upper surface 11 of the conveyor belt 10. In this way, each scraper 24 removes any build-up of material 19 adhering to the associated sealing strip 22. This prevents such material wearing the belt 10 and also reduces the frictional forces between the belt 10 and the sealing strips 22 so reducing the power requirement.

The frequency at which the pairs of scrapers 24 are provided along the upper surface 11 of the conveyor belt 10 may be varied in accordance with the cohesiveness and abrasiveness of the material being conveyed. Where the material has great tendency to stick to the sealing strips 22 and is particularly abrasive, scrapers 24 will be provided very frequently to ensure that no build-up of material occurs. On the other hand, where the material is neither cohesive nor abrasive, the scrapers 24 may be provided at greater intervals.

As shown in Figures 4, 5 and 6 the scraper of each pair may take different forms.

In the embodiment of Figure 4, a scraper 25 is provided which is generally the same as the scraper 24 of the embodiment of Figures 1 to 3 but has a greater length in the direction of the length of the conveyor belt 10. This may be useful if the material is particularly adhesive and requires greater removal force In the embodiment of Figure 5, a scraper 26 is provided which has angled leading and trailing edges 27a,27b and an upper surface provided with spaced projections 28.

In this arrangement, material can collect in the gaps between the projections 28 and, as the scraper 26 is passed round pulleys at the ends of the system, the gaps will open and the material will be released.

In the embodiment of Figure 6, a scraper 29 is provided that is similar to the scraper 26 but is of greater axial length. Hard inserts 30 may also be introduced to the leading edge of the projections 28.

The scrapers described above with reference to the drawings can be of any suitable material. They can be attached to the conveyor belt by bonding, by adhesives, by vulcanizing or by recessed fixings. They could be formed integrally with the conveyor belt 10 during its construction. There may be as few as one pair of scrapers. The scrapers of each pair need not be axially aligned - they could be axially staggered.

The embodiments of Figures 5 and 6, which are provided with projections, are only one example of scrapers which have upper surfaces that vary in depth along their length. Other forms of variable depth surface may be provided.

Claims

1. A conveyor system comprising an endless conveyor belt having an under surface, support means for supporting the conveyor belt in an elongate path, a pair of parallel spaced cables extending longitudinally along the conveyor belt and engaging said under surface, drive means for driving the cables to drive the conveyor belt in said path between a loading end and unloading end thereof, a feed chute mounted adjacent said loading end of the conveyor belt and including a pair of spaced side plates defining a channel therebetween for containing loose material loaded on to the conveyor belt at the loading end, each side plate having a lower edge adjacent to but spaced from the conveyor belt surface, the conveyor belt being provided with at least two scrapers of limited length in the direction of the length of the belt, said scrapers being spaced laterally of the width of the belt and projecting from the surface of the belt, the scrapers moving with the belt and engaging intermittently respective lower edges of the side plates to release material adhering thereto.

2. A conveyor system according to claim 1 wherein the conveyor belt includes an upper load carrying surface, the scrapers being carried on said upper load carrying surface.

3. A conveyor belt comprising upper and lower belt surfaces and formations adjacent each edge of the belt for receiving respective cables for supporting and driving the belt, the upper surface of the belt being provided with at least two scrapers which are of limited length in a direction parallel to the length of the belt, which are spaced laterally of the width of the belt and which project from the surface of the belt.

4. A conveyor according to claim 2 or claim 3 wherein each scraper comprises a pad of flexible material attached to said upper load carrying surface.

5. A conveyor according to claim 4 wherein each pad has an upper surface remote from said conveyor load carrying surface, the thickness of each said pad between said upper surface and said load carrying surface varying in a direction parallel to the length of the conveyor.

6. A conveyor according to claim 5 wherein each said pad includes at least one projection.

7. A conveyor according to claim 6 wherein each said pad includes at least two projectors, the at least two projections being aligned in a direction parallel to the length of the conveyor belt and being spaced in said parallel direction.

8. A conveyor according to claim 6 wherein each projection has an edge which is a front edge and the direction of travel of the conveyor belt, each front edge including a hardened insert.

9. A conveyor according to claim 6 wherein said at least one projection has an edge which is a front edge in the direction of travel of the conveyor belt, said front edge having a face which extends at an angle relative to the load carrying surface of the conveyor belt.

10. A conveyor according to claim 2 or claim 3 wherein two scrapers are provided, the two scrapers being axially aligned relative to the length of the conveyor belt and laterally spaced.

11. A conveyor according to claim 2 or .claim 3 wherein a plurality of pairs of scrapers are provided, the scrapers of each paid being axially aligned relative to the length of the conveyor belt but laterally spaced, and the pairs of scrapers being axially spaced along the length of the conveyor belt.

12. A conveyor system substantially as hereinbefore described with reference to Figures 1 to 3 and to Figures 1 and 2 as modified by Figure 4 or Figure 5 or Figure 6 of the accompanying drawings.

13. A conveyor belt substantially as hereinbefore described with reference to Figures 1 to 3 and to Figures 1 and 2 as modified by Figure 4 or Figure 5 or Figure 6 of the accompanying drawings.