GB2205804A

GB2205804A - Improved conveyor belt scraper

Info

Publication number: GB2205804A
Application number: GB08814307A
Authority: GB
Inventors: Ian Keith Stallard
Original assignee: C & J D Barton Ltd
Current assignee: C & J D Barton Ltd
Priority date: 1987-06-16
Filing date: 1988-06-16
Publication date: 1988-12-21
Anticipated expiration: 2008-06-16
Also published as: GB8814307D0; GB8713978D0; GB2205804B

Abstract

A conveyor belt scraper (1) for scraping a surface of a conveyor belt (3), comprises an elongate blade (5) including at least two edges (7, 9) suitable for use as belt engaging surfaces; each end of the blade being rotatably mounted to mounting means (11), the mounting means (11) being mounted on a support member (13) for movement towards and away from the belt surface (3); a bearing member mounted on the support member (13), capable of being mounted at at least two different distances from the belt surface (3); biasing means acting between the bearing member and the mounting means (11) to urge the mounting means (11) and the blade (5) toward the belt (3); the scraper including locking means (19) capable of locking the blade (5) in a number of different positions angularly with respect to the mounting means (11) such that each of said edges (7, 9) of the blade suitable for use as belt engaging surfaces may be locked into position facing the belt (3). <IMAGE>

Description

IMPROVED CONVEYOR BELT SCRAPER FIELD OF THE INVENTION The invention relates to an improved Conveyor Belt Scraper.

When conveyor belts are used to transport loose material the belt can often get very dirty quickly; with material adhering to the surface of the belt. Scrapers are often used to clean a conveyor belt on its return run. Often the scraper includes a blade which is spring biased towards the surface of the return of the conveyor tending to scrape off any dirt or debris as the belt passes over the blade. In many industries it has been found that such scraping greatly improves the efficiency of operation of the conveyor bell.

REVIEW OF THE PRIOR ART Conveyor belt scrapers typically comprise an elongate blade which is mounted to lie across the return run of a conveyor belt and biased towards the surface of the belt so that one surface of the blade engages the belt surface. In order to achieve a scraping action the blade is biased towards the belt to push the belt engaging surface onto the belt.

Often the biasing is achieved by a pair of springs with one spring being mounted at each end of the blade to give an even biasing force across the belt. As the scraper is operated the bell engaging surface gradually wears away and as this happens the spring biasing means push the blade towards the belt so the newly exposed belt engaging surface is in contact with the belt. However as the blade moves further in a direction towards the belt the spring (often compression springs) start to lose their effectiveness and the force applied on the blade decreases. Thus, gradually the effectiveness of the scraping action of the blade is reduced.

One conveyor belt scraper which was devised to overcome this problem was one described in UK Patent No. 2054 504B.

The scraper disclosed in that patent specification i 5 one in which the elongate blade has its ends connected to first and second mounting means; each mounting means being slidably mounted on a post tilting away from the belt surface.

A collar surrounds each post and a compression spring is coiled around the post between 1he collar and the mounting means so that force is applied by the spring in the distance between the collar and the mounting means. The scraper provides adjustment means which allows the collar to be moved axially of the post in which the adjustment means comprises a pin engaging a helical groove with one point on the post and the other on the collar. In this scraper as the bell engaging surface of the blade is worn away and the blade has lo move in a direction towards the belt, the collar can also be moved along the post in a direction towards the belt to maintain sufficient force applied by the compression spring on the mounting means. This scraper, therefore, exlended the life of the blade for the scraper since they could be used for a lol longer.However a number of different problems arose with this particular scraper.

The scraper is specifically designed for wiping clean belt surfaces in dirty situations but the structure of the scraper with the compression spring mounted outside the post and the use of the helical groove and pin was such ihat the dirt and debris scraped off the belt could easily interfere with the operation of the scraper. The scraper was designed to use blades on which opposite edges of the blade could be utilised as the belt engaging surface. However, once one belt engaging surface of the blade had been utilised the arrangement for changing the position of the blade was very complicated. The scraper included means for removing the mounting means from the post by sliding the mounting means up the post over the top of the post.Once this has been done the whole blade and mounting means would have to be rotated through 180 and the mounting means remounted on each post to allow the second face of the blade to be utilised. This operation was time-consuming and complicated, especially so in situ. Such conveyor belt scrapers are often used in tlie middle of big industrial plant and usually mounted beneath a conveyor belt and often a lot of other machinery. The blade can only be changed or its position changed with this procedure which is difficult when working in a confined space. Clearly, in most cases, this would be inconvenient.

SUMMARY OF THE INVENTION According to the invention there is provided a conveyor belt scraper for scraping a surface of a conveyor belt the scraper comprising an elongate blade including at least two edges suitable for use as belt engaging surfaces; each end of the blade being rotatably mounted to mounting means, the mounting means being mounted on a support member for movement towards and away from the belt surface; a bearing member mounted on the support member, capable of being mounted at, at least two different distances from the belt surface; biasing means acting between the bearing member and the mounting means to urge the mounting means and the blade toward the belt; the scraper including locking means capable of locking the blade in a number of different positions angularly with respect to the mounting means such that each of said edges of the blade suitable for use as belt engaging surfaces may be locked into position facing the belt.

In this way a simple scraper system is provided which can adjust the position of the bearing member to extend the life of one belt engaging surface of the blade and at the same time allow the elongate blade to be rotated to another position to allow a second belt engaging surface to be used. This can be done without having to disturb he conveyor belt and its overlying equipment or t he scraper itself. Thus, the efficiency of the scraper unit is greatly increased.

It is preferred that the elongate blade consists of an elongate bar of rectangular cross-section with two opposite edges forming the belt engaging surfaces. In this case the elongate blade need only be lockable in two different positions with respect to the mounting means, one being 180 from the other.

With most conveyor belts, the conveyor runs parallel to the ground or horizontal base structure and the support means consist of a vertical post with the in-use position of the blade being perpendicular to the belt and thus, parallel to the post. However, in some forms of machinery, the conveyor belt does not run horizontally but runs at an angle. However, in most cases, the support means consist of a vertical post and thus, in some cases the blade in order to be perpendicular to the conveyor belt would be non-parallel to the post. It is therefore preferred that the locking means can lock the blade in many different angular positions with respect to the mounting means so that the scraper can be used to scrape many different types of belts at different angles.With this form of scraper the blade can also be arranged so that it does not lie perpendicular to the belt if a different form of scraping action is required as it is with some materials. Preferably, the blade can be locked into up to eight different angular positions with respect to the mounting means.

The support means may comprise an upright post, having mounted upon it the bearing member with a compression spring forming the biasing means mounted above the bearing member to push in an upwards direction on the mounting means to push the blade in an upwards direction. Alternatively, the bearing member can be arranged to lie above the mounting means with the biasing means consisting of a tension spring which pulls the mounting means upwards. In this case, as the belt engaging surface becomes worn, the mounting means is pulled closer to the bearing member and the tension spring starts to lose it effectiveness.

In this case the bearing member then has to be moved further away from the belt surface to increase the force on the blade.

In an alternative embodiment the support means may comprise a post extending downwardly from the machinery supporting the conveyor belt. This can be arranged with the biasing means either pushing upwards against the mounting means or pulling upwards.

The biasing means may comprise coiled tension or compression springs. In the case of the biasing means pushing against the mounting means, the biasing means may comprise a rod of springy material such as hard rubber or polyurethane. This helps to avoid the need for lubrication of the biasing means.

Preferably the blade is a polyurethane, polyethylene or other plastics blade which is mounted to at least one elongate member extending between the two mounting means. Typically, the blade will be bolted to the elongate bar. Preferably in this case, the blade is rotatable to a position substantially parallel to the belt so that, at this position, the bolt can be removed and the blade slid out from beneath the belt for replacement of the blade. In this way, the change of blade can be effected with no requirement for disturbing either the conveyor belt of the scraper itself. This greatly increases the working time of the scraper since the conveyor belt does not have to be disturbed in any way and only has to stopped for a short time to allow replacement of the blade. This gives a great saving in both time and expense.

Preferably the blade is mounted between two packing bars to support it more firmly. More preferably the two bars between which the blade lie form a clamp assembly held together by a set of tightening means which tighten the connection between the two bars to hold the blade firmly in position. It is preferred that the tightening means are arranged such that when they are loosened they are not removable from the assembly in order to allow the blade to be removed. In this way there is no danger of any loose screws or nuts being lost in this position beneath the conveyor belt where il would be very difficult to find any loose parts.

It is preferred that the support means consists of a hollow leg in which is mounted, slideably, a box assembly. The box assembly has one closed end which provides provides the bearing member. Preferably the spring forming the biasing means is housed within the box assembly and bears against a mounting block, slideably mounted within the box assembly. In this way the spring and all the moving parts are housed within the leg which helps to cut down any effect of any debris falling from the belt could have on the workings of the scraper. Preferably the end of the spring box assembly has a bore passing through it and the leg has a number of holes passing through it so that a bolt can be passed through one of the holes on the leg and the bore through the spring box assembly to hold it in position.If the position of the bearing member with respect lo the belt is to be changed, the spring box assembly is merely slid within the leg so that a different hole is aligned to the bore in the spring box assembly. This provides a very simple way of effecting the adjustment required to maintain the effectiveness of the spring biasing means.

BRIEF DESCRIPTION OF DRAWINGS Two conveyor belt scrapers in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1. is a schematic perspective view of a first conveyor belt scraper in use; Figure 2. is an exploded perspective view of part of the scraper of Figure 1; and Figure 3. is an exploded perspective view of part of a second conveyor belt scraper.

DESCRIPTION OF THE PREFERRED EMBODIMENT A conveyor belt scraper 1 as shown in figures 1 and 2 is devised for scraping the surface of a conveyor belt 3 on its return run. The scraper 1 comprises an elongate blade 5 which includes two edges, 7 and 9, which are suitable for use as belt engaging surfaces. Each end of the blade 5, is rotatably mounted to the mounting means 11, as shown in detail in figure 2. The mounting means 11 is mounted on a support member 13, for movement towards and away from the belt surface 3.

A bearing member 15 is also mounted with respect to the support member 13 and can be mounted at at least two different distances from the belt surface 3. Biasing means 17 in the form of a compression spring acts between the bearing member 15 and the mounting means 11 to urge the mounting means 11 and the blade 5 in a direction towards the belt 3. The scraper also includes locking means 19 which allows the blade 5 to be locked into two different positions, one position in which edge 7 faces the belt 3 and the second position in which edge 9 faces the b.elt 3.

The blade 5 is an elongate bar of polyurethane having a rectangular cross-section. It is mounted between two mounting bars 21, 23, each of which is mounted between two barrels 25 and 27. The bars 21 and 23 include aligned bores 29 through which may be passed bolts 31 to clamp the two bars 21 and 23 together to hold the blade 5 firmly in position. Each barrel 25, 27 is rotatably mounted on a cylindrical support 33, as shown in figure 2. Figure 2 shows only the mounting of one end of the blade in detail.

The other end corresponds. Bores 35 on the barrel 25 and 27 can be aligned to a locking bore 37 on cylinder 33 and a nut passed into the bores 37 and 35 to lock the blade in a given posilion. In this case each barrel 25 includes two diametrically opposed bores 35 to allow the blade to be locked in two different positions 1800 from on another to allow edge 7 and edge 9 respectively to act as the belt engaging surface. The cylinder 37 is connected via bracket 39 to bar 40 which forms the mounting means 11.

The support 13 consists of a hollow upright leg of square cross-section including a set of spaced apart bores 41.

A box assembly 43, also of hollow square cross-section, is slideable within leg 13. The box assembly has a closed end 15 remote from belt 3 which is closed. This closed end 15 forms the bearing member against which spring 17 bears. The region 15 of the box assembly 43 includes a bore 45 which can be aligned with any one of the spaced apart bores 41 to hold the box assembly 43 and thus bearing member 15 in any one of four different positions at different distances with respect to the belt 3. Housed within the box assembly 43 is compression spring 17 and a split clamp assembly 47 which encloses the end 40 of the mounting means 11 which slide into the box assembly 43 through groove 49 which is of length longer than the height of end 40 to allow the end 40 to move up and down within groove 49.

A bolt 51 extends downwards through box assembly 43 to bear against the top of the split assembly 47 to hold the blade down away from the belt 3 for installation and maintenance purposes. When the scraper blade 5 is to be placed in its in-use position, bolt 51 is loosened to allow the mounting means 11 to move freely within the groove 49.

A slay 53 extends between the leg 13 to give added rigidity.

In use, the box assembly 43 is moved to its lower most position with bore 45 aligned with the lower-most of bores 41 in leg 13. A bolt is then passed through the two aligned bores to hold the box assembly 43 rigidly with respect to the support means 13. The spring 17 urges the split assembly 47 and therefore the mounting means 11 in an upwards direction to urge one edge 7 forming the belt engaging surfaceveengagement with the belt so that it has an effeclive scraping action. As the belt engaging surface 7 becomes worn the effectiveness of spring 17 will be reduced and the force applied on the belt by the blade will decrease.

Once the blade starts to lose effectiveness the bolt which passes through bore 35 and 37 on the barrel and cylinder assembly is loosened and the whole barrel and blade assembly is rotated through 1800 so that the diametrically opposed bore (not shown) is then aligned to bore 37. The bolt is then passed through the bores to lock the blade in position with the opposing edge 9 acting as the belt engaging surface.

When this engaging surface has also become worn, the bolt which passes through aligned bores 41 and 45 is then loosened and the box assembly 43 is moved upwards so that the bolt 45 is aligned to the next one up of the bores 41. Thus the @@@etime of the blade 5 is extended to eight times @@@ normal life. Clearly il is very simple to total the blade and to move the box assembly without disturbing belt 3.

When the belt engaging surfaces 7 and 9 are both completely worn the screw 51 can be used to hold the blade assembly away from the belt and the barrel assembly is rotated through 90 so that the blade lies substantially horizontal. The screws 31 are loosened and this allows the two bars to lose their clamping action to allow the blade 5 to be removed to allow insertion of a new blade. Again, this can be carried out without disturbing either the conveyor belt scraper or the conveyor belt and any surrounding machinery.

A second conveyor belt scraper is shown in figure 3. This arrangement is for use in situations where it is inconvenient to have the conveyor belt scraper mounted beneath the conveyor belt and where it is more preferable to have the conveyor belt scraper suspended from above the conveyor belt. The blade and the means for rotatably mounting the blade are all the same as the corresponding parts of the first conveyor belt scraper and the same reference numerals will be used for similar parts. The leg 53 is mounted such that its hollow open end 55 faces downwards. The leg 53 consists of a hollow upright leg of square crosssection similar to leg 13. It includes a set of spaced apart bores 57 at its lower end. A box assembly 59 has a closed end 61 which includes a loop 63. This closed end 61 is the end which will be remote from the conveyor belt.The box assembly 59 is slidable within leg 53. A tension spring 65 has a hook 67 on its upper end and hook 69 on its lower end. A clamp 71 includes a loop 73. In use hook 69 of spring 65 is hooked into loop 73 and hook 67 hooks onto loop 63. The box assembly 59 includes a slot 75 for accommodating the mounting means 11. Clamp 71 also includes a slot 77 of similar size. Spring 65 and clamp assembly 71 are mounted within box assembly 59. The upper end of the box assembly 59 includes bsre 79. In use the box assembly 59 is mounted within leg 53 by passing a bolt through the lower most of holes 57 and hole 79 to hold the box section 59 rigidly in position.

This places the blade beneath the conveyor belt.

When one face of the blade has been worn out the blade is flipped over thrpugh a 1800. Once this second face has been worn out the box section 59 is moved in an upwards direction until bore 79 is aligned with the second of the bores 57.

This second conveyor belt assembly is of particular use in mounting above the head drum of a conveyor belt. In this position the scraper is extremely effective and the debris scraped off the conveyor belt is easy to collect.

It will be readily apparent that the method of rotating the barrels 25 and 27 on the supports may be in the form of a ratchet wheel. Thus, the ratchet can define the required positions of the blade with respect to the belt and a lever can simply be used to rotate the barrel to its required position. Typically, such a ratchet would be an eight point ratchet.

It has been found that in some applications it is necessary for a roller to be spring biased against the belt on the opposite side of the belt to the conveyor belt scraper. The roller cannot be rigidly in position since if an obstruction on the 'conveyor belt passes between the roller and the conveyor belt scraper and neither is allowed to move out of the way, damage to both the roller and the conveyor belt scraper could occur. It is therefore required that the roller is movable away from the conveyor belt. Clearly, it would be possible to mount a roller on the same mounting post 13 or 53 of the first or second conveyor belt scraper. Also, a similar spring type assembly could be used for the correct mounting arrangement.

Claims

I A -o^.-e-z^r belt scraper for scraping a surface of a conveyor belt, the scraper comprising an elongate blade including at least two edges suitable for use as belt engaging surfaces; each end of the blade being rotatably mounted to mounting means, the mounting means being mounted on a support member for movement towards and away from the belt surface; a bearing member mounted on the support member, capable of being mounted at at least two different distances from the belt surface; biasing means acting between the bearing member and the mounting means to urge the mounting means and the blade toward the belt; the scraper including locking means capable of locking the blade in a number of different positions angularly with respect to the mounting means such that each of said edges of the blade suitable for use as belt engaging surfaces may be locked into position facing the belt.
2 A conveyor belt scraper according to Claim 1, in which the elongate blade consists of an elongate bar of rectangular cross-section with two opposite edges forming the belt engaging surfaces.
3 A conveyor belt scraper according to Claim 1 or 2, in which the locking means can lock the blade in many different angular positions with respect to the mounting means.
4 A conveyor belt scraper according to Claim 3, in which the blade can be locked into up to eight different angular positions with respect to the mounting means.
5 A conveyor belt scraper according to any one of the preceding Claims, in which the support member comprises a post which extends downwardly from the machinery supporting the conveyor belt.
6 A conveyor belt scraper according to any one of the preceding Claims, in which the support means comprises an upright post having mounted upon it the bearing member with a compression spring forming the biasing means mounted above the bearing member to push in an upwards direction on the mounting means to push the blade in an upwards direction.
7 A conveyor belt scraper according to any one of Claims 1 to 6, in which the bearing member lies above the mounting means with the biasing means consisting of a tension spring which pulls the mounting means upwards.
8 A conveyor belt scraper according to any one of Claims 1 to 6, in which the biasing means comprises a rod of hard rubber or polyurethane in compression.
9 A conveyor belt scraper according to any one of the preceding Claims, in which the blade is a polyurethane, polyethylene or other plastics blade which is mounted to at least one elongate member extending between the two mounting means.
10 A conveyor belt scraper accroding to Claim 9, in which the blade is rotatable to a position substantially parallel to the belt so that, at this position, the blade can be removed from the elongate member and the blade slid out from beneath the belt for replacement of the blade.
11 A conveyor belt scraper according to Claim 9 or 10, in which the blade is mounted between two packing bars which form a clamp assembly held together by a set of tightening means which tighten the connection between the two bars to hold the blade firmly in position.
12 A conveyor belt scraper according to Claim 11, in which the tightening means are arranged such that when they are loosened they are not removable from the assembly in order to allow the blade to be removed.
13 A conveyor belt scraper according to any one of the preceding Claims, in which the support means consist of a hollow leg in which is mounted, slideably, a box assembly, the box assembly has one closed end which provides the bearing member, and the spring forming the biasing means is housed within the box assembly and bears against a mounting block, slideably mounted within the box assembly.
14 A conveyor belt scraper according to Claim 13, in which the end of the spring box assembly has a bore passing through it and the leg has a number of 'holes passing through it so that a bolt can be passed through one of the holes on the leg and the bore through the spring box assembly to hold it in position.
15 A conveyor belt scraper for scraping a surface of a conveyor belt arranged substantially as described herein with reference to and as illustrated in Figures 1 and 2 of the drawings.
16 A conveyor belt scraper for scraping a surface of a conveyor belt arranged substantially as described herein with reference to and as illustrated in Figures 1 and 2 when modified in accordance with Figure 3 of the accompanying drawings.