WO2004041687A1

WO2004041687A1 - Conveyor belt scraper

Info

Publication number: WO2004041687A1
Application number: PCT/ZA2002/000170
Authority: WO
Inventors: Michael Edmond Smith
Original assignee: Michael Edmond Smith
Priority date: 2002-11-08
Filing date: 2002-11-08
Publication date: 2004-05-21
Also published as: AU2002346745A1

Abstract

A conveyor belt scraper assembly is provided comprising a mounting assembly (3, 7, 8) supporting a blade carrier (14) and a scraper blade arrangement (18) carried by the blade carrier. The blade carrier has a generally circular configuration whereof the axis extends operatively at generally right angles to a surface of a convoyer belt (16) to be cleaned with the scraper blade arrangement following said circular configuration. The blade carrier is rotatable about the axis of said circular configuration with the scraper blade arrangement presenting an operative scraping edge (19) at a position axially spaced from the blade carrier itself. Means are provided for causing rotation of the blade carrier abot its axis during operative contact of the blade with a conveyor belt surface. Such means may include adjustment mechanism (7) whereby one lateral side of the blade arrangement can be urged into contact with a conveyor belt surface with a force greater than that with which the other side of the blade arrangement is urged into contact with the conveyor belt surface. The result is that a greater drag is created at the one side of the conveyor belt by more firm contact with the scarper blade to thereby cause rotation of the blade carrier, in use.

Description

CONVEYOR BELT SCRAPER

FIELD OF THE INVENTION

This invention relates to a conveyor belt scraper of the type employed for removing adherent material from the surface of a conveyor belt, typically underneath the belt on its return pass at or towards the delivery end of the conveyor belt.

BACKGROUND TO THE INVENTION

Conveyor belt scrapers that are in general use usually comprise at least one flat blade, and typically a plurality of staggered flat blades, extending transversely across the width of the conveyor and arranged to extend upwards at generally right angles to the surface of the conveyor so that the upper free edge of the blade contacts the surface of the conveyor belt to remove adherent material from it.

There are more or less sophisticated mechanisms for maintaining the blades in contact with the conveyor belt surface whilst allowing them to move away from the surface under conditions in which damage to the belt or blades and their associated mechanism is likely.

Typically, the blades have an operative edge made of tungsten in view of its wear resistance and in order to provide the scraper blades with a satisfactory working life. The disadvantage of this is that, whilst the blades may last reasonably well, the belt life is often shortened as the adherent material is often abrasive and the tungsten urges the abrasive material more firmly into contact with the belt surface with obvious resultant deleterious effects. The tungsten blades also have the disadvantage that their cost is considerable when replacement is eventually necessary.

Existing scraper assemblies also require regular adjustment and maintenance in order to ensure effective operation and this leads to considerable labour being necessary with the attendant costs thereof.

Furthermore, most, if not all, of existing conveyor belt scrapers are not particularly effective at removing fine adherent particles and moisture.

Still further, tungsten blades cannot be effectively used in instances in which the conveyor belts are spliced utilizing certain types of steel clips or the like.

OBJECT OF THE INVENTION

It is, accordingly, an object of this invention to provide a conveyor belt scraper that overcomes, at least to some extent, one or more disadvantages associated with certain existing conveyor belt scraper assemblies.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a conveyor belt scraper assembly comprising a mounting assembly supporting a blade carrier and a scraper blade arrangement carried by the blade carrier, the conveyor belt scraper assembly being characterized in that the blade carrier has a generally circular configuration whereof the axis extends operatively at generally right angles to the surface of a conveyor belt to be cleaned with the scraper blade arrangement following said circular configuration; in that the blade carrier is rotatable about the axis of said circular configuration with the scraper blade arrangement presenting an operative scraping edge at a position axially spaced from the blade carrier itself; and in that means are provided for causing rotation of the blade carrier about its axis during operative contact of the blade with a conveyor belt surface.

Further features of the invention provide for the scraper blade arrangement to comprise one or more strips of resiliently deformable abrasion resistant material, typically a suitable grade of polyurethane, clamped to a circular outer support surface of the blade carrier; for the blade carrier to assume the form of a spoked wheel rotatable about a central journal or bearing; for the mounting means to comprise a pair of opposite attachment members for attachment one to each side of a conveyor belt support assembly, the attachment members supporting between them, by way of an adjustment mechanism, a transverse support beam for the blade carrier; and either for the blade carrier to be dimensioned to extend across substantially the entire width of a cooperant conveyor belt or, alternatively, for the blade carrier to be dimensioned such that two, three, or more of such blade carriers are required to extend substantially across the entire width of a conveyor belt in staggered relationship to each other.

A still further feature of the invention provides for the adjustment mechanisms to each comprise one or more compression spring and bolt assemblies whereby one lateral side of the blade arrangement can be urged into contact with a conveyor belt surface with a force greater than that with which the other side of the blade arrangement is urged into contact with the conveyor belt surface. The arrangement may even be one in which the blade at one side of the conveyor belt contacts the conveyor belt surface whilst the other side of the blade arrangement is out of contact or almost out of contact with the belt surface. This arrangement constitutes the said means for causing rotation of the blade carrier during operative contact of the blade with the conveyor belt surface in consequence of the greater drag created at the side of the conveyor belt more firmly contacted by the scraper blade. In this case, it will be understood, that the blade carrier is freely rotatable about its own axis. In order that the above and other features of the invention may be more fully understood one embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:-

Figure 1 is a perspective view of one embodiment of conveyor belt scraper according to the invention;

Figure 2 is a sectional elevation thereof;

Figure 3 is an elevation of the conveyor belt scraper illustrating, in end view, a conveyor belt with which it is operatively associated in dotted lines;

Figure 4 is a side view of the conveyor belt scraper illustrating a conveyor belt with which it is operatively associated in dotted lines;

Figure 5 is a plan view of an arrangement in which a plurality of blade and blade carriers are employed to span the width of a conveyor belt; and,

Figure 6 is a view similar to Figure 5 and illustrating an alternative arrangement of the plurality of blades and blade carriers. DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In the embodiment of the invention illustrated in Figures 1 to 4 of the drawings, a conveyor belt scraper comprises a mounting assembly, generally indicated by numeral (1), consisting of a pair of generally upright attachment members (2) each of which is operatively attached at its upper end (3) to one side of the supporting frame (4) of a belt conveyor (5).

The attachment members support at their lower ends (6) the lower ends of upwardly extending spring and bolt adjustment mechanisms (7) that support at their upper ends the two ends of a transverse support beam (8) that extends between them. The spring and bolt mechanisms each comprises a pair of spaced compression springs (9) through which a bolt (10) extends, the bolts being associated at their lower ends with a flange (12) carried by the lower end of the associated attachment member and at their upper ends with flanges (13) fixed to the ends of the support beam.

In this embodiment of the invention the conveyor belt scraper has a single blade assembly that comprises a spoked circular blade carrier (14) that is freely rotatable about a bearing (15) supported by the beam, the carrier having a diameter slightly less than the width of a conveyor belt (16) in association with which it is to be used. The carrier has a cylindrical outer surface to which is clamped, by means of an encircling clamping ring (16), one edge (17) of a scraper blade (18) in the form of a strip of polyurethane sheet of a suitable thickness and the opposite edge (19) of which forms the operative scraping edge. The strip of polyurethane material is preferably such that it encircles the entire periphery of the carrier and its two ends form a butt joint (20) in the circular configuration of the blade.

To set the conveyor belt scraper up for operation, and with the two attachment members secured in position to the conveyor frame members (4) to extend downwards therefrom, the scraping edge (19) is directed upwards at the return pass of the conveyor belt (16). The bolts (10) are then adjusted so that the compression springs urge the one side of the circular scraper blade into contact with the conveyor belt more firmly than the other side. Indeed the other side of the scraper blade need hardly touch the surface of the belt at all. Whatever the exact arrangement that is chosen, the result is that the drag on the scraper blade at one side of the conveyor belt, during movement of the belt, is greater than the drag, if any, at the diametrically opposite side of the blade. The result is that the blade and carrier rotate in consequence of the greater drag at the one side and this sets up a highly effective scraping action in a circular path across the width of the belt.

It has been found that a highly effective scraping action is achieved utilizing a scraper as described above. The polyurethane blade has extremely long- lasting qualities and does not inflict damage on a conveyor belt to the same extent as a tungsten blade. The unit is substantially self-cleaning; the blade seldom requires replacement; the unit is of low maintenance requirement; and the unit has a minimum of working parts. Tests conducted to date indicate that a Shore hardness of the polyurethane material from which the scraper blade is manufactured is advantageously from about 80 to about 90. The thickness of the material may typically be from about 5 mm to about 100 mm. However, it is also envisaged that, in certain applications, a laminated construction could well be of advantage and, in such an instance, the different layers could have different Shore hardnesses appropriate to the material or selection of materials to be conveyed by the relevant conveyor.

Numerous variations may be made to the embodiment of the invention described above without departing from the scope hereof. In particular, and as illustrated in Figure 5, the blade and blade carrier could be made significantly smaller in diameter with regard to the width of the conveyor belt and a plurality of them could be arranged in staggered relationship across the width of the belt as indicated by numeral (21) in Figure 5. The direction of rotation of the plurality of carrier and blade assemblies could be the same or different. As illustrated in Figure 6 different arrangements of plural blade and blade carrier assemblies are possible.

The invention therefore provides an extremely simple yet highly effective conveyor the scraper that it is envisaged could be manufactured in numerous different forms other the embodiments of the invention described above simply being illustrative of the invention.

Claims

CLAIMS:

1. A conveyor belt scraper assembly comprising a mounting assembly (3, 7, 8) supporting a blade carrier (14) and a scraper blade arrangement (18) carried by the blade carrier, the conveyor belt scraper assembly being characterized in that the blade carrier has a generally circular configuration whereof the axis extends operatively at generally right angles to the surface of a conveyor belt (16) to be cleaned with the scraper blade arrangement following said circular configuration; in that the blade carrier is rotatable about the axis of said circular configuration with the scraper blade arrangement presenting an operative scraping edge (19) at a position axially spaced from the blade carrier itself; and in that means are provided for causing rotation of the blade carrier about its axis during operative contact of the blade with a conveyor belt surface.

2. A conveyor belt scraper assembly as claimed in claim 1 in which the scraper blade arrangement comprises one or more strips (18) of resiliently deformable abrasion resistant material.

3. A conveyor belt scraper assembly as claimed in claim 2 in which the scraper blade comprises one or more strips of a suitable grade of polyurethane.

4. A conveyor belt scraper assembly as claimed in either one of claims 2 or 3 in which the strip or strips is or are clamped to a circular outer support surface of the blade carrier means of a clamp (16) encircling the blade carrier.

5. A conveyor belt scraper assembly as claimed in any one of the preceding claims in which the blade carrier assumes form of a spoked wheel rotatable about a central journal or bearing (15).

6. A conveyor belt scraper assembly as claimed in any one of the preceding claims in which the mounting means comprises a pair of opposite attachment members (2) for attachment one to each side of a conveyor belt support assembly (4), the attachment members supporting between them, by way of an adjustment mechanism (7), a transverse support beam (8) for the blade carrier.

7. A conveyor belt scraper assembly as claimed in claim 6 in which the adjustment mechanisms each comprise one or more compression spring and bolt assemblies whereby one lateral side of the blade arrangement can be urged into contact with a conveyor belt surface with a force greater than that with which the other side of the blade arrangement is urged into contact with the conveyor belt surface such that a greater drag is created at the one side of the conveyor belt by more firm contact with the scraper blade.

8. A conveyor belt scraper assembly as claimed in any one of the preceding claims in which the blade carrier is freely rotatable about its own axis.