GB2364985A

GB2364985A - Conveyor belt scraper

Info

Publication number: GB2364985A
Application number: GB0112751A
Authority: GB
Inventors: Alan Bowler
Original assignee: Horizon
Current assignee: Horizon
Priority date: 2000-05-27
Filing date: 2001-05-25
Publication date: 2002-02-13
Also published as: GB0012881D0; GB0112751D0

Abstract

A conveyor belt scraper comprises a beam 1 and at least one buffer 2 which is removably mounted on the beam by snap-engagement of a flexible attachment part 5 of the buffer with the beam. The beam may have one or more projecting pins 12 which are received in one or more corresponding holes 7 in the attachment part. The attachment part preferably fits closely around the beam and embraces more than half its circumference. The buffer may be formed from an elastomeric material and may have a hollow region 8. The buffer may support an individual scraper blade 3 or may have an integral blade portion (18, Fig. 3). The integral blade portion may comprise a wear line (20, Fig. 3) along a face thereof so as to indicate the maximum extent of wear before replacement is necessary.

Description

<Desc/Clms Page number 1> Conveyor Belt Scrapers This invention relates to conveyor belt scrapers of a kind suitable for use in scraping the working surfaces of continuous conveyor belts, to remove material which remains adhered to the belts after the belts have deposited loads therefrom. The belt surfaces are therefore continuously cleaned for reuse. Such belt scrapers are commonly used on conveyor belts employed in the quarying and mining industries, but are used generally in other industries as well. It is common practice to provide a first scraper (usually referred to as a primary scraper) to act against the belt at a position below the level of an outward belt run where the belt is supported by a head pulley between its outward and return runs. The primary scraper ordinarily comprises a scraping blade which extends across the width of the belt, the blade lying at a sharp acute angle to the belt surface. A second scraper (usually referred to as a secondary scraper) is commonly provided to act against the belt at a position immediately after the belt has left the surface of the head pulley in commencing its return run. The secondary scraper ordinarily comprises a scraping blade which extends across the width of the belt and stands substantially perpendicularly to the belt surface. One known form of scraper, suitable for use as a secondary scraper, comprises a beam which is arranged to extend transversely of the conveyor belt run and supports a row of blade-carrying, shock- absorbing, mountings moulded of an elastomeric material such as rubber or polyurethane; the shock-absorbing mountings are commonly referred to as buffers. Individual scraping blades are held by the row of buffers to form

either a substantially continuous or a staggered blade edge. The blade edge may, for example, be of tungsten carbide. The actual material providing the blade edge is selected according to the duties it must perform, some blades being of rigid polyurethane. In one known arrangement a buffer comprises lower and upper bifurcated portions embracing, respectively, an upwardly projecting flange of the beam and a lower portion of the blade, a middle portion of the buffer provides effectively a stiff hinge between the upper and lower portions, whereby to provide some resilience in the mounting for deflection of the blade edge in the direction of the belt path (i.e. laterally of the blade). In another known arrangement the buffer is resiliently compressible in the direction towards and away from the belt to be cleaned. The buffer is fixed to the beam but a part of the buffer carrying the scraping blade is resiliently movable relative to the beam, thereby providing the required resilient compressibility.

It is also known to provide primary scrapers which similarly comprise buffers/blades of an elastomeric material supported on a beam. These buffers/blades may have integral scraping portions which act on the belt to be cleaned. Hitherto the buffers of primary and secondary scrapers have been fixed to their respective beams by means of bolts. Access to the bolts for fitting and removing the buffers to and from the beams can be restricted so that applying and releasing the bolts may not be easy. Furthermore, some of the material which a belt carries inevitably becomes adhered to the buffers and beams and it can be difficult to release the bolts when buffers are required to be removed for maintenance or replacement.

According to the present invention a conveyor belt scraper is provided comprising a beam and at least one buffer which is removably mounted on the beam by means of a flexible attachment part of the buffer which is snap-engaged with the beam. The attachment part of the buffer and the beam may have mating male and female components at which the snap-engagement is made. For example, the beam may have one or more projecting elements, such as a pin or pins which engage with one or more holes, sockets or recesses in the attachment part of the buffer. The flexibility of the attachment part is employed to achieve the snap-action in the engagement. The flexibility must allow deflection of the attachment part sufficient to make and release the snap-engagement of the buffer with the beam, but it should resist unintentional flexing of the attachment part so as to avoid accidental release of the buffer from the beam. The snap-engagement may be released by levering a portion of the attachment part away from the beam. An aperture or recess may be provided in the portion in which a screwdriver or other suitable tool may be engaged to assist in levering the portion away from the beam. Preferably the attachment part fits closely about the beam, embracing more than half the circumference of the beam. The close fit resists undesirable penetration of foreign matter between the buffer and the beam. Resilient compressibility of the buffer may be afforded by the material and/or the form of the buffer. The buffer may be made of rubber, polyurethane or other suitable elastomeric material. It may have a hollow portion which enhances the resilient compressibility.

The buffer may provide a shock-absorbing mounting for a primary or a secondary scraper. It may support an individual scraper blade. The resilience of the buffer allows movement of the scraper relative to the beam so as to enable it to accommodate variations in the attitude of the conveyor belt being cleaned, during the travel of the belt, and thereby maintain effective cleaning contact with the belt. Preferably the buffer is adapted to support a scraper blade offset from a diametral plane through the beam. Preferably the arrangement is such that when the buffer is installed for use with a conveyor belt the scraper blade it supports extends perpendicularly or substantially so with respect to the surface of the belt to be cleaned. Two or more of the buffers may be mounted on the beam. When the buffers provide mountings for secondary scrapers, by having each of the buffers arranged to support the scraping blades offset from a diametral plane through the beam, the buffers may be mounted on the beam either in a first manner in which the scraping blades are aligned and present a continuous, or substantially continuous, blade edge, or in a second manner, in which adjacent buffers are mounted the opposite way round on the beam, having the scraping blades staggered along the beam, thereby presenting a discontinuous blade edge. End portions of the scraping blades may be formed so that end portions of the scraping blades of adjacent buffers on the beam, in either manner of mounting, overlap. An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is an end view of a conveyor belt secondary scraper, in accordance with the invention;

Figure 2 is a front view of the conveyor belt scraper, and Figure 3 in a side view of a buffer for a conveyor belt primary scraper in accordance with the invention. Referring to Figures 1 and 2, a secondary scraper is shown which comprises a beam 1 of metal cylindrical tube, a buffer 2 of compressibly resilient rubber or polyurethane and a steel scraping blade 3. The buffer 2 may be moulded or extruded to shape. The buffer 2 is a one-piece element having a lower portion 4 of notionally rectangular section and an upper portion 5 of generally equilateral triangular section. A part-cylindrical seating recess 6 formed in the lower portion 4 opens through opposite ends of the buffer and through the bottom of the buffer. The seating recess 6 is of a diameter complementary to the external diameter of the beam and extends circumferentially for substantially more than 180 , typically approximately 270 . Diametrically opposed holes 7 extend into the seating recess from front and back faces of the buffer at the lower portion. The holes 7 are at spaced positions along the recess. The lower portion 4 forms an attachment part of the buffer. A semi-cylindrical compression hollow 8 symmetrically formed in the upper portion 5 also opens through the opposite ends of the buffer and has its arcuate surface towards the apex of that portion. Adjacent but offset from the apex of the upper portion is an upwardly extending flange 9, one face 10 of the flange lying on the central longitudinal plane of the buffer extending through the apex of the upper portion 5. Both holes 11 are formed in the flange 9 at spaced positions along its length.

Split tubular pins 12 are securely fixed diametrically in the beam at spaced positions along the beam corresponding to the positions of the holes 7 in the lower portion of the buffer. Opposite ends 12' of the pins 12 project from the beam by distances corresponding to the thickness of the material of the lower portion containing the holes 7. The resilience of the material of the buffer allows the lower portion to be flexed sufficiently for it to be sprung over the beam and its pins 12 for the beam to be engaged in the seating recess 6. The buffer is positioned so that the holes 7 in the lower portion align with and receive with snap- engagement the projecting opposite ends 12' of the pins 12 as the lower portion is forced onto the beam. As soon as the seating recess is coaxial with the beam the resilience of the buffer material urges the lower portion back towards its normal unstressed condition so that the projecting opposite ends 12' penetrate fully into the holes 7, thereby securely retaining the buffer on the beam. If the buffer is required to be removed from the beam, for replacement or servicing, the lower portion can be levered away from the opposite sides of the beam, by use of a suitable levering tool, or even a screwdriver, to release the pins 12 from engagement with the holes 7. A hole, not shown, may be formed in the lower portion at at least one side of the seating recess 6 in which the levering tool can be engaged for the levering action. The scraping blade 3 is bolted to the flange 9 at the upper portion 5 of the buffer, against the face 10 of the flange. Bolts 13 are engaged in the bolt holes 11 in the flange. The secured scraping blade 3 is offset from the central 6 longitudinal plane of the buffer extending through the apex of the upper portion. The scraping blade is longer than the buffer and it is secured so that it's opposite ends 3' overhang the ends of the buffer. The

overhanging ends 3' are reduced to half thickness by cutting the blade away from one side at the ends.

In use of the scraper the resilience of the material of the buffer and the compression hollow 8 in its upper portion permit the scraping blade 3 to move a little towards and away from the belt being scraped, although the blade is constantly urged into engagement with the belt by the resilience of the buffer.

A number of the buffers are mounted in a row on the beam in the manner described and releasably retained thereto by the snap-engagement of the pins 12 in the holes 7 of the lower portions of the buffers. The buffers may all be mounted the same way round on the beam so that the scraping blades 3 they carry all align, overlapping at their overhanging ends 3', to provide a continuous blade edge along the beam. Alternatively adjacent buffers may be mounted the opposite way round on the beam, and so, because of the offset arrangement of scraper blades on the buffers, the blades are staggered along the beam with a circumferential gap between the overhanging ends 3' of adjacent blades. A discontinuous blade edge is thus presented along the beam. The circumferential gap is quite small and the blades are a11 contained within the plan area of the beam. Suitable markings may be provided on the buffers for ready indication of the manner of mounting the buffers on the beam for the continuous or discontinuous blade edge arrangements of the scraper blades.

Referring now the Figure 3, a buffer 14 for a primary scraper is shown. This buffer is also made of compressibly resilient rubber or polyurethane, as a moulding or extrusion. It has lower and upper portions 15, 16 substantially similar to those of the buffer 2 described above and it is snap-engaged on a beam, not shown, in similar manner. In this example the compression hollow 17 in the upper portion has a pointed arced

surface directed towards the top of the upper portion but it may be of semi -cylindrical shape as in the example described above. The essential difference is that this buffer 14 has an integral blade portion 18 extending upwardly with a slight, rearwardly inclined, curve from the top of the upper portion 16. The blade portion 18 tapers at its upper end to a scraping edge 10. A wear line 20 is formed by a groove along a face of the blade portion to indicate the maximum extent to which the blade portion may be worn down by use before the buffer needs to be replaced. As before, the resilience of the material of the buffer constantly urges the scraping edge 19 of the blade portion 18 into scraping engagement with the conveyor belt with which the primary scraper is used, and the resilience and the compression hollow 17 allow some resilient movement of the blade portion towards and away from the beam.

A number of the buffers are mounted in a row in line on the beam to make up the primary scraper.

For some applications of use it may be desirable for the buffers described, whether for the primary or the secondary scraper, to have the thickness of their lower portions at opposite sides of the seating recesses increased for added strength, but the facility for snap-engagement with the beams would still be retained.

Claims

CLAIMS 1. A conveyor belt scraper comprising a beam and at least one buffer which is removably mounted on the beam by means of a flexible attachment part of the buffer which is snap-engaged with the beam.
2. A conveyor belt scraper according to claim 1 wherein the attachment part and the beam have mating male and female components at which the snap-engagement is made, the flexibility of the attachment part enabling the snap-action in the engagement.
3. A conveyor belt scraper according to claim 2 wherein the beam has one or more projecting elements which engage with one or more holes, sockets or recesses in the attachment part.
4. A conveyor belt scraper according to claim 2 wherein the or each projecting element is a pin.
5. A conveyor belt scraper according to any preceding claim wherein the attachment part has a portion which is leverable away from the beam to release the snap-engagement.
6. A conveyor belt scraper according to any preceding claim wherein the attachment part fits closely about the beam, embracing more than half the circumference of the beam.
7. A conveyor belt scraper according to any preceding claim wherein the buffer is made of elastomeric material and has a hollow portion which enhances the resilient compressibility of the buffer.

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8. A conveyor belt scraper according to any preceding claim wherein the buffer is adapted to support an individual scraper blade.
9. A conveyor belt scraper according to any preceding claim wherein the buffer is adapted to support a scraper blade offset from a diametral plane through the beam.
10. A conveyor belt scraper according to any preceding claim wherein the buffer is adapted to support a scraper blade such that when the buffer is installed for use with a conveyor belt the scraper blade extends perpendicularly, or substantially perpendicularly, with respect to the surface of the belt to be cleaned.
11. A conveyor belt scraper according to any of claims 1 to 7 wherein the buffer has an integral blade portion extending away from the attachment part.
12. A conveyor belt scraper according to claim 11 wherein the blade portion extends with a curve away from the attachment part.
13. A conveyor belt scraper according to claim 11 or claim 12 wherein the blade portion tapers to a scraping edge.
14. A conveyor belt scraper according to any of claims 11 to 13 wherein the blade portion is formed with a wear line along a face thereof to indicate the maximum extent to which the blade portion may be worn down before use before the buffer needs to be replaced.
15. A conveyor belt scraper according to any preceding claim wherein a number of the buffers are removably mounted in a row on the beam by snap-engagement of their attachment parts with the beam.

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16. A conveyor belt scraper according to claim 15 as dependent from claim 9 wherein the buffers are mounted on the beam such that their scraper blades are aligned and present a continuous, or substantially continuous, blade edge along the beam.
17. A conveyor belt scraper according to claim 15 as dependent from claim 9 wherein the buffers are mounted on the beam such that adjacent ,buffers support their respective scraper blades offset to opposite sides of a common diametral plane through the beam, the blades, thereby, being staggered along the beam and presenting a discontinuous blade edge along the beam.
18. A conveyor belt scraper substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.
19. A conveyor belt scraper substantially as described herein with reference to Figure 3 of the accompanying drawings.