AU1356100A - Improvements relating to conveyor scrapers - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION STANDARD PATENT Improvements Relating to Conveyor Scrapers" The following statement is a full description of this invention, including the best method of performing it known to me: IMPROVEMENTS RELATING TO CONVEYOR SCRAPERS This invention concerns the use of scrapers for conveyors and in particular, scrapers for cleaning material adhering to rubber belt conveyors. It has particular applicability to conveyor systems used in mining and mineral processing operations.

In the use of rubber belt conveyors to transport bulk materials, the problem of materials sticking to the conveyors is well known. Many types of scraper systems have been 10 proposed and developed for scraping such adhering material from the belt. Metal scraping blades either rubbing on the belt, or suspended slightly above the belt, are widely used, as oo are chains rubbing against the belt. Even complex and expensive systems involving air jets directed adjacent the belt have been used to lift off the adhering material.

However there is a need for an improved scraper system which offers the following advantages: inexpensive to purchase and install (ii) effective cleaning of the belts (iii) installs onto a wide range of conveyor frames 20 (iv) regular maintenance minimised low cost of consumables (vi) low wear induced upon belt (vii) adaptable to a wide range of conveyor widths, in particular the standard widths of rubber belting An aim of the present invention is to provide a conveyor scraper which addresses the present difficulties.

Accordingly, in one aspect the invention provides a scraper for cleaning a conveyor belt, said scraper comprising a plate member having a first end attached to an adjusting element and a second end, opposite the first end, removably engaged with a scraping tip, the scraping tip having a slot formed therein into which is snugly accommodated said second end of the plate member in order to retain the scraping tip on the plate member, and the adjusting element being adapted to adjust and retain the plate member such that the scraping tip is brought into biased engagement with the belt.

In another aspect the invention provides a replaceable scraping tip for a conveyor belt scraper, said scraping tip having a slot let into a face thereof said slot forming a pouch adapted to snugly accommodate a rectangular plate member such that the scraping tip may be retained on the plate member.

10 Preferably the scraper tip has the general shape of a rectangular solid having long, medium and short edges, except that one of the long edges distal of the slot is displaced from its position in a true rectangular solid to a parallel position outwards from such rectangular solid shape. The tip may be moulded entirely from elastomer plastics or rubber material.

oooo• Alternatively the tip may have a body formed of elastomeric plastics or rubber material and 15 a hard metal or ceramic strip bonded to the plastics material along its wiping edge.

In a further aspect the invention provides a method of cleaning a conveyor belt comprising: .ooooi affixing a scraper as defined above adjacent a belt on a conveyor, (ii) adjusting said adjusting element to move the plate member to bring the scraping 20 tip into biased contact with the belt, and (iii) operating the conveyor with the scraper so positioned, whereby the scraping tip cleans from the belt material adhering to the belt.

Examples of the invention will now be described with reference to the attached drawings where: Figure 1 is a diagrammatic general side view of the head of a conveyor incorporating a scraper assembly according to one embodiment of the present invention; Figure 2 is a partial cutaway detail view of the scraper assembly shown in Figure 1; Figure 3 is a view, in direction A shown on Figure 2, of one component of the assembly in Figure 2; Figure 4 is a view, in direction B shown on Figure 2, of the component shown in Figure 3; Figure 5 is a view, in direction A shown on Figure 2, of another component of the assembly in Figure 2; and Figure 6 is a view, in direction B shown on Figure 2, of the component shown in Figure Referring to Figure 1, a rubber conveyor belt 4 is wound around an end pulley 6 at the head of a conveyor. The pulley rotates in the direction shown by the curved arrow. A scraper 10 assembly 8 bears against the belt where it overlies the pulley in order to clean off material left adhering to the belt. The scraper assembly 8 is bolted to a support bracket 10 which in turn is welded to a tubular shaft 12. The shaft 12 is held by a bearing (not shown) at each of its ends and is rotated and clamped at the appropriate position to bring the scraper into oeeoe contact with the belt 4. The shaft 12 thus provides an adjustable element for supporting the 15 scraper. The means for accomplishing such positional clamping of the shaft are not shown in Figure 1, but many ways are well known to the skilled worker and need not be described here in further detail. In practice a plurality of scraper assemblies 8 would be fixed to the *ooo° shaft alongside each other in order to extend coverage across the full width of the belt.

20 Referring to Figures 2 to 4, the scraper assembly shown in Figure 2 has a generally rectangular plate member 18 forming a scraper body having a head end 19 and a foot On the head is engaged a scraper tip 22 which forms the blade of the scraper. At the foot a rubber block 24 is bonded on one face to the body plate 18 and on the opposite face to a backing plate 26. The backing plate 26 has two bolts 28 protruding outwardly through holes with the bolt heads encapsulated within the rubber block 24. In Figure 2 part of the rubber block and backing plate are shown as a cut away view in order to better illustrate the structure.

Rubber isolators of the general form of block 24 are well known, and would be moulded in place against the body plate 18 and the backing plate 26. The bolts 28 are used with nuts to affix the scraper assembly to the rotatable support The plate forming the scraper body has a bend 32 of about 300 about midway up so forming two flat panels, a head panel 33 and a foot panel 34. At the head 19 of the scraper body the head panel narrows at shoulders 36 to create a tongue 38 in the same plane as the remainder of the head panel.

Referring to Figures 2, 5 and 6, the scraping blade or tip 22 is formed as a single moulding of a suitable elastomeric polyurethane material. It has the shape of a pentagonal prism having two adjacent included angles ac and 13 of 90* and having an acute included angle 0 located between an obtuse included angle y and an included angle 8 in the range of 1800 to 10 270 The edge 44 subtended by acute angle 0 is sharper than the others and is used for bearing against the conveyor belt 4 to scrape or wipe adherent material from the bolt. The face 56 of the blade 22 opposite the wiping edge 44 forms a narrow base of the blade. The base face 56 has a slot 58 of length, width and depth to match the width, thickness and depth respectively of the tongue 38. The slot thus forms a pouch into which the tongue is 15 fully and snugly accommodated.

The head corners 42 of the tongue 38 are trimmed to provide a taper for easier insertion of the tongue into the slot. When the tongue is pressed into the slot, in the manner of a spade connection, the shoulders 36 are brought to bear against the base face 56. The tongue and 20 slot are a firm press fit by hand; this provides sufficient support to the blade while also **allowing convenient replacement of the blade when required. In Figure 2 the blade 22 is shown in section to better illustrate the connection.

When installing the scraper assembly, the foot 20 is affixed to the bracket 10 which is then rotated and fixed in position when the blade exerts a predetermined force against the belt.

This force is typically in the order of 4 to 10kg when measured by a spring balance hooked on to the top of the blade.

As the scraper operates, it may ride over some material tightly adhering to the belt. The body plate 18 and the blade 22 are comparatively stiff components and do not flex significantly, but the blade is allowed to move away from the belt due to the resilience in the rubber block 24. The deflection away from the belt occurs through pivoting of the scraper about the axis 50 through the rubber.

As an alternative to the arrangement described above, instead of the shaft 12 being clamped in position with the appropriate preload set up, the force exerted by the blades onto the belt may be facilitated by having the shaft freely rotatable in its bearings and having a torque exerted on the shaft by use of a lever arm and counterweights.

The scraping tip 22 described above is formed entirely of polymer or rubber material.

10 Alternatively it may be largely polymer or rubber material but have its wiping edge 44 •formed of tungsten carbide or some other hard metal or ceramic strip bonded to the plastics material. The hard metal or ceramic strip may be contiguous or be formed from a plurality of components such as tungsten carbide strips sized approximately 50mm x 10mm x 3mm.

•ooo° The hard metal or ceramic strip may be bonded to the outside of the wiping edge 44 or be S 15 bonded into the polymer or rubber slightly below the surface of the wiping edge 44 so that the hard metal or ceramic strip comes into contact with the conveyor belt only after the overlying elastomer is worn away.

Throughout this specification, unless the context requires otherwise, the word "comprise", V 20 and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.

Claims (8)

1. A scraper for cleaning a conveyor belt, said scraper comprising a plate member having a first end attached to an adjusting element and a second end, opposite the first end, removably engaged with a scraping tip, the scraping tip having a slot formed therein into which is snugly accommodated said second end of the plate member in order to retain the scraping tip on the plate member, and the adjusting element being adapted to adjust and retain the plate member such that the scraping tip is brought into biased engagement with the belt.

2. A scraper according to claim 1 said scraping tip having the general shape of a rectangular solid having long, medium and short edges, except that one of the long edges distal of the slot is displaced from its position in a true rectangular solid to a parallel position outwards from such rectangular solid shape.

3. A scraper according to claim 1 or 2 wherein said scraping tip is a moulding of plastics or rubber material. Vo..o.

4. A scraper according to claim 1 or 2 wherein said scraping tip is a moulding of 20 elastomer material. 00o o° A scraper according to claim 2 wherein said scraping tip comprises a body formed of elastomeric plastics or rubber material and a hard metal or ceramic strip bonded to said elastomeric material along said wiping edge.

6. A replaceable scraping tip for a conveyor belt scraper, said scraping tip having a slot let into a face thereof said slot forming a pouch adapted to snugly accommodate a rectangular plate member such that the scraping tip may be retained on the plate member.

7. A scraping tip according to claim 6 having the general shape of a rectangular solid having long, medium and short edges, except that one of the long edges distal of the slot is 8 displaced from its position in a true rectangular solid to a parallel position outwards from such rectangular solid shape.

8. A scraping tip according to claim 6 or 7 wherein said scraping tip is moulded from plastics material.

9. A scraping tip according to claim 7 wherein said scraping tip comprises a body formed of plastics material and a hard metal or ceramic strip bonded to the plastics material along said wiping edge. A method of cleaning a conveyor belt comprising: affixing a scraper according to any one of claims 1 to 5 adjacent a belt on a :..'.conveyor, (ii) adjusting said adjusting element to move the plate member to bring the S 15 scraping tip into biased contact with the belt, and (iii) operating the conveyor with the scraper so positioned, whereby the scraping tip o•.o ••cleans from the belt material adhering to the belt. oooo Dated this 27th day of January 2000 :Graeme Seabrook DUNCAN by his patent attorney Norman Morcom