WO2001023284A1

WO2001023284A1 - Conveyor belt cleaner tensioning device

Info

Publication number: WO2001023284A1
Application number: PCT/AU2000/001175
Authority: WO
Inventors: Robert Patrick Gilbert; Kevin Rudd
Original assignee: Mato Australia Pty Ltd
Priority date: 1999-09-27
Filing date: 2000-09-27
Publication date: 2001-04-05
Also published as: ATE285372T1; ES2233458T3; EP1218268A4; NZ518313A; CA2385687C; EP1218268B1; DE60016942T2; US6820734B1; DE60016942D1; EP1218268A1; CA2385687A1

Abstract

The present invention relates to a conveyor belt cleaning apparatus for use with belt conveyors. The invention provides a conveyor belt cleaning apparatus (1) for use with a belt conveyor, the cleaning apparatus comprising a first arm (20a) and a second arm (20b) adapted to support a scraping blade (30), the first and second arms being rotatably mounted on a shaft (2) for independent rotation about an axis, the rotation of the arms causing corresponding positional adjustments of the scraping blade (30) with respect to the belt. The mountings (21a, 21b) of each arm (20a, 20b) on the shaft (2) includes a biasing means which, in use, acts to bias the arms towards the conveyor belt. The apparatus further includes an intermediate arm (40) located midway between the first arm (20a) and the second arm (20b) one end of which is connected to the shaft (2) and the opposing end of which is connected to the scraping blade (30) to provide support for the scraping blade (30).

Description

TITLE: CONVEYOR BELT CLEANER TENSIONING DEVICE

FIELD OF THE INVENTION

The present invention relates generally to belt conveyors, and more particularly to a

conveyor belt cleaning apparatus for use with such conveyors.

BACKGROUND TO THE INVENTION

Belt conveyors are used in a variety of applications for the transportation of

particulate or granular material, such as coal, grain, ore, minerals, and the like.

One problem commonly encountered with belt conveyors is the tendency for

particulate material to adhere to the carrying surface of the conveyor belt. This problem is

particularly significant in applications such as underground mining operations and coal

transportation, where the material moving on the belt must continually be sprayed with

water to suppress dust. The water mixes with the fine particulate component of the coal or

other material to form a slurry which is particularly prone to sticking to the surface of the

belt. This phenomenon reduces the transportation efficiency, and increases the running and

maintenance costs of the conveyor.

In an attempt to ameliorate these problems, various conveyor belt cleaners in the

form of scraping devices have been developed to scrape residual debris from the surface of

the belt. These are normally positioned on the underside of the conveyor, at or near the

head pulley and just past the intended discharge point, such that the lower run of the belt on

its return loop is substantially clean.

However, known scraping devices have several inherent disadvantages. The most

significant of these relates to the need for the scrapers to accommodate surface

irregularities in the belt. Such irregularities most commonly take the form of belt fasteners, which are typically formed from steel and protrude beyond the surface of the belt. These

fasteners can cause hardened scraping blades to break, chip or shatter, leading to reduced

scraping efficiency and downtime whilst repair operations take place. This can also cause

premature failure of the belt fasteners.

In an attempt to avoid these problems, some scraping blades have been formed from

relatively soft materials such as polyurethane, polypropylene and other plastics. Whilst

being better able to accommodate surface irregularities in the belt without breakage, such

blades are prone to rapid abrasive wear, and hence require frequent replacement. This is

costly, and again often results in undesirable downtime.

A further problem with known scraping devices relates to the need for each of several

scraping blades to be individually adjusted to the correct position relative to the belt, and

relative to the adjacent blades. This set-up procedure is time consuming, labour intensive

and expensive. Moreover, frequent recalibration is normally required in order to

accommodate wear of the scraping blades.

It is an object of the present invention to provide a belt scraping assembly which

overcomes or substantially ameliorates at least some of these disadvantages of the prior art.

SUMMARY OF THE INVENTION

Accordingly, a first aspect of the present invention provides a conveyor belt

cleaning apparatus for use with a belt conveyor, said cleaning apparatus comprising a first

arm and a second arm adapted to support a scraping blade, said first and second arms being

mounted to a support frame for rotation about respective first and second pivot axes, such

that rotation of said arms about said pivot axes effects corresponding positional

adjustments of the scraping blade with respect to the belt. A second aspect of the present invention provides a conveyor belt cleaning apparatus

for use with a belt conveyor, said cleaning apparatus comprising a first arm and a second

arm adapted to support a scraping blade, said first and second arms being mounted to a

support frame for rotation about respective first and second pivot axes, such that rotation of

said arms about said pivot axes effects corresponding positional adjustments of the

scraping blade with respect to the belt, said apparatus further including a third arm

positioned intermediate said first and second arms and adapted to support said scraping

blade.

A third aspect of the present invention provides a conveyor belt cleaning apparatus

for use with a belt conveyor, said cleaning apparatus comprising a scraping blade, a first

arm adapted to support said scraping blade, and a second arm adapted to support said

scraping blade, said first and second arms being mounted to a support frame for rotation

about respective first and second pivot axes, such that rotation of said arms about said pivot

axes effects corresponding positional adjustments of the scraping blade with respect to the

belt, said apparatus further including a third arm positioned intermediate said first and

second arms and adapted to support said scraping blade.

Advantageously, the present invention provides a conveyor belt cleaning apparatus

for positioning a scraping blade against the surface of a conveyor belt and which is

designed to maintain a relatively uniform blade pressure across substantially the full width

of the blade, whilst maintaining the blade in a plane substantially perpendicular to the

plane of the conveyor belt surface. Preferably, the first and second arms are mounted for independent rotation about a

common pivot axis. Preferably the pivot axis lies in a plane transverse to the direction of

movement of the conveyor belt.

Preferably the support frame is mounted to a fixed frame of the belt conveyor

assembly, such that the pivot axis of the first and second arms is also substantially fixed.

Preferably the apparatus further includes resilient bias means adapted to provide a

degree of resilient displacement to the first and second arms towards and away from the

belt, thereby enabling the scraping blade to traverse surface irregularities in the belt.

Preferably, the mountings of the first and second arms each include a resilient biasing

means so as to urge the scraper blade into operative scraping engagement with the belt.

Preferably the mountings can be adjusted to provide a predetermined degree of pre-load

force to produce the desired contact pressure between the scraper blade and the conveyor

belt.

In use, the apparatus is preferably positioned on the underside of the conveyor belt.

Preferably, the apparatus allows the opposing sides of the cleaner blade to move

independently of each other so as to conform to any conveyor belt movement.

The present invention has particular application with a curved scraping blade,

although the invention may be adapted for use with a straight (also known as "inline")

scraping blade. Currently, belt cleaners which employ a curved blade use an adjustment

mechanism which produces an arced motion so as to bring the cleaner blade into contact

with the conveyor belt. This results in a non-uniform pressure across the width of the

blade, with greater pressure being applied around the mid point of the cleaner blade. Unless the context clearly requires otherwise, throughout the description and the

claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive

as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including,

but not limited to".

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way of example

only, with reference to the accompanying drawings in which:

Fig. 1 is a side elevation of one preferred embodiment of a belt cleaner assembly

according to the present invention, adapted for mounting to a belt conveyor;

Fig. 2 is a perspective view of the belt cleaner assembly shown in Fig. 1 ;

Fig. 3 is a perspective view of a second preferred embodiment of a belt cleaner

assembly according to the present invention;

Fig. 4 is an enlarged perspective view of the scraping blade support arm circled in

broken line in Fig. 3;

Fig. 5 is a side elevation of the belt cleaner assembly shown in Fig. 3;

Fig. 6 is a partially exploded perspective view of the scraping blade mounting and

tensioning sub-assembly;

Fig. 7 is a further perspective view of the mounting and tensioning sub-assembly

shown in Fig. 6;

Fig. 8 is a perspective view of the belt cleaner assembly illustrating the torque and

load vectors when the belt cleaner assembly is in use;

Fig. 9 is a side view of the belt cleaner assembly illustrating the torque and load

vectors when the belt cleaner assembly is in use; and Fig. 10 is a perspective view of the belt cleaner assembly illustrating the torque and

load vectors when the belt cleaner assembly is in use.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the accompanying drawings, the present invention provides a conveyor

belt cleaning apparatus 1 for use with a conveyor comprising an endless flexible belt

extending between head pulleys (not shown). The head pulleys, intermediate rollers, drive

mechanisms and associated support structures of conventional belt conveyor assemblies are

well known to those skilled in the art, and so will not be described in further detail.

Referring to Figs. 1 and 2, a first preferred embodiment of a conveyor belt cleaning

apparatus according to the present invention is depicted. The conveyor belt cleaner 1

includes a shaft 2 which, in use, is mounted on the conveyor structure so as to extend

transversely across the width of the conveyor. At each end of the shaft 2 there is provided

a mounting sub-assembly 3 a, 3 b in order to mount the belt cleaner to the frame of the

conveyor (not shown). In use, the belt cleaner assembly is mounted on the underside

(commonly referred to as the "return side") of the conveyor belt so as to clean the carrying

surface of the conveyor belt as it returns from its discharge point. The direction of motion

of the conveyor belt is indicated by the arrow X.

The mounting sub-assemblies 3a, 3b include bearings 4a, 4b within which respective

ends of the shaft 2 are rotatably mounted. The bearings 4a, 4b are each mounted on

mounting plates 5a, 5b of the respective mounting sub-assemblies 3a, 3b. Each mounting

sub-assembly 3a, 3b further includes a respective adjustment means 6a, 6b at each end of

the shaft 2 in the form of a threaded bolt and nut arrangement 7, 8 so as to provide for

adjustment of the position of the shaft 2 relative to the plane of the conveyor belt. In use the adjustment means 6a, 6b provides for the movement of each end of the shaft 2 in a

substantially vertical plane as illustrated by arrow A in Fig. 1.

Fixedly mounted on each end of the shaft 2 are arms 10a, 10b. In use, each arm 10a,

10b is connected to a tensioning means (not shown) in the form of a spring, pneumatic or

hydraulic ram, or the like which applies a tension force to the arm in the direction indicated

by the arrow B in Fig. 1. This force is transmitted via the arms 10a, 10b to provide a

torque (indicated by the arrow T in Fig. 2) to the shaft 2 and bring scraping blade 30 into

contact with the carrying surface of the conveyor belt. In this way a pre-load force is

applied to the scraping blade 30 which allows the blade to follow the surface of the belt as

it moves during operation.

The belt cleaner assembly further includes a pair of arms 20a, 20b, which are

mounted on the main shaft 2. The arms 20a, 20b are pivotably connected to respective

ends of a curved cleaner blade 30 so as to support the cleaner blade at its ends and provide

a relatively uniform and controlled contact pressure between the blade and the conveyor

belt surface across the full width of the blade. The mountings 21a, 21b of the arms 20a,

20b on the shaft 2 are adapted to provide for independent tensioning so as to allow each

arm to move independent of the other and thereby allow for any belt movement. Each

mounting 21a, 21b on the shaft includes a resilient biasing means (not shown) which

permits a degree of biased rotation for each arm with respect to the axis of the shaft 2 and

which, in use, acts to bias the respective arms 20a, 20b towards the conveyor belt. In the

embodiment depicted in Figs. 1 and 2 the mountings 21a, 21b preferably include a

resiliency deformable material, such as rubber, which acts to resiliency bias the respective arms 20a, 20b towards the conveyor belt. However it should be appreciated that other

forms of biasing may be employed, such as springs for example.

The assembly further includes a supporting arm arrangement 40 located intermediate

the end arms 20a, 20b. Preferably the intermediate arm 40 is located mid-way between the

end arms 20a, 20b. The intermediate arm arrangement 40 assists in keeping a uniform

pressure on the blade over the full width of the blade. The linkage comprises an arm 41

which is connected at one end to the shaft 2 and is pivotably connected to arm 42 at hinge

point 43. The supporting arm 40 acts to maintain the cleaner blade substantially

perpendicular to the surface of the conveyor belt.

Referring to Figs. 3 to 10 a second preferred embodiment of the present invention is

depicted. For the sake of clarity, those components which are shared with the embodiment

depicted in Figs. 1 and 2 are provided with identical reference numerals.

In this embodiment the mounting sub-assembly 3 a, 3 b for each end of the shaft 2

includes a mounting bush 5 la, 5 lb within which the shaft 2 is rotatably mounted. Each

mounting bush 51a, 51b is held in a respective mounting block 52a, 52b which is attached

to mounting plate 5a, 5b. The mounting plates 5a, 5b are each provided with an elongated

slot 11 through which bolts 12 pass so as to secure the mounting block to the mounting

plate. Each mounting sub-assembly includes a respective adjustment means 6a, 6b at each

end of the shaft 2 in the form of a threaded bolt 7 and nut 8 arrangement so as to provide

for adjustment of the position of the shaft 2 relative to the plane of the conveyor belt as

previously described with reference to the embodiment of Figs. 1 and 2. When the end of

the shaft is located in the correct position the bolts 12 are tightened to secure the mounting

block in position on the mounting plate. Each mounting sub-assembly further includes a pair of inner and outer torsion

springs and collars which are mounted on the shaft 2 and which are configured to impart

the desired loadings upon the cleaner blade 30. As with the embodiment of Figs. 1 and 2,

each end of the cleaner blade is pivotably connected to an arm 20a, 20b. The arms 20a,

20b are connected to a pair of first collars 53a, 53b which are rotatably mounted on

respective ends of the shaft 2. A pair of second collars 54a, 54b are rotatably mounted on

respective ends the shaft but can be locked in position on the shaft 2 by means of locking

screws/bolts 55. A pair of first torsion springs 56a, 56b are interposed between each pair

of adjacent first and second collars with the free ends of the torsion spring engaging in the

collars. By rotatably adjusting the relative position of the first and second collars on the

shaft it is possible to adjust the spring tension in the torsion springs 56a, 56b and hence the

biasing torque imposed on the arms 20a, 20b connected to each end of the cleaner blade.

Each mounting sub-assembly further includes an outer locking collar 57a, 57b

through which the shaft 2 passes and which can be locked in position on the shaft by means

of locking screws/bolts 58. A second torsion spring 59a, 59b is interposed between each

outer locking collar 57a, 57b and its respective mounting block 52a, 52b, with one free end

60a, 60b of the torsion spring being engaged in the respective collar 57a, 57b and the

second free end 61a, 61b being respectively engaged in the mounting block 52a, 52b.

As with the embodiment depicted in Figs. 1 and 2, the assembly further includes a

supporting arm arrangement 10 located intermediate the end arms 20a, 20b. Preferably the

intermediate arm 40 is located midway between the end arms 20a, 20b. The linkage

comprises an arm 41 which is connected at one end to the shaft 2 and is pivotally connected to arm 42 at hinge point 43. In the embodiment depicted in Figs. 3 to 10, the

arm 42 is adjustable in length by means of a threaded shaft and nut arrangement.

Referring to Figs. 8 to 10, typical force and torque vectors imposed on the cleaner

assembly when in use are illustrated. The shaft 2 is free to rotate in the mounting bushes

51a, 51b and is attached to the cleaner blade 30 by means of the outer arms 20a, 20b and

the intermediate arm 40. The outer torsion spring 59a, 59b on each end of the shaft has one

free end engaged in its adjacent mounting block 52a, 52b and its other free end engaged in

its respective outer torsion collar 57a, 57b. The outer torsion springs are supplied in sets of

two, with one being wound left hand and the other right hand. By means of the outer

torsion springs, the outer torsion collar on each end of the shaft provides a torque to the

shaft 2 which acts against the shaft's tendency to rotate away from the conveyor belt when

under load. This provides an upward force "FC" acting at the cleaner's blade centre (see

Fig. 10).

Adjustment of the magnitude of the force "FC" is achieved by holding the shaft

stationary, loosening the locking bolts in the torsion collar, rotating the torsion collar in the

direction of "AIL" and "AIR" respectively until the desired pre-load is achieved and then

tightening the locking bolts to secure the torsion collar in the new position.

The cleaner blade connecting arms 20a, 20b provide the forces "F2L" and "F2R" at

each end of the cleaner blade via the inner torsion springs. The forces "F2L" and "F2R"

are increased by adjusting the inner torsion collars position on the shaft in the direction

indicated by "A2L" and "A2R". The forces "F2L" and "F2R" act independently of each

other and thus provide the even distribution of cleaner blade pressure on the belt while

allowing the blade to follow any variations in the plane of the conveyor belt. Advantageously, the assembly of the present invention provides for a belt cleaner

assembly which provides a relatively uniform pressure across the full width of the cleaner

blade whilst enabling a full adjustable inline tensioning device.

Although the invention as been described with reference to specific examples, it will

be appreciated by those skilled in the art that the invention may be embodied in many other

forms.

Claims

1. A conveyor belt cleaning apparatus for use with a belt conveyor, said cleaning

apparatus comprising a first arm and a second arm adapted to support a scraping blade, said

first and second arms being mounted to a support frame for rotation about respective first

and second pivot axes, such that rotation of said arms about said pivot axes effects

positional adjustments of the scraping blade with respect to the belt.

2. A conveyor belt cleaning apparatus for use with a belt conveyor, said cleaning

positional adjustments of the scraping blade with respect to the belt, said apparatus further

including a third arm positioned intermediate said first and second arms and adapted to

support said scraping blade.

3. A conveyor belt cleaning apparatus for use with a belt conveyor, said cleaning

apparatus comprising a scraping blade, a first arm adapted to support said scraping blade,

and a second arm adapted to support said scraping blade, said first and second arms being

that rotation of said arms about said pivot axes effects positional adjustments of the

blade.

4. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 3 wherein

there is a relatively uniform blade pressure across substantially the full width of the blade, whilst maintaining the blade in a plane substantially perpendicular to the plane of the

conveyor belt surface.

5. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 3 wherein the

first and second arms are mounted for independent rotation about a common pivot axis.

6. A conveyor belt cleaning apparatus as defined in claim 4 wherein the pivot axis lies

in a plane substantially transverse to the direction of movement of the conveyor belt.

7. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 5 wherein the

support frame is mounted to a fixed frame of the belt conveyor assembly, such that the

pivot axis of the first and second arms is substantially fixed.

8. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 6 wherein the

apparatus further includes resilient bias means adapted to provide a degree of resilient

displacement to the first and second arms.

9. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 7 wherein the

mountings of the first and second arms each include a resilient biasing means so as to urge

the scraper blade into operative scraping engagement with the belt.

10. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 8 wherein the

mountings can be adjusted to provide a predetermined degree of pre-load force to produce

the desired contact pressure between the scraper blade and the conveyor belt.

11. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 8 and

adapted to be positioned on the underside of the conveyor belt, so as to clean the carrying

surface of the conveyor belt as it returns from its discharge point.

12. A conveyor belt cleaning apparatus as defined in any one of claims 1 to 10 wherein

said scraping blade is of a curved type.