AU2918395A

AU2918395A - Conveyor belt cleaning

Info

Publication number: AU2918395A
Application number: AU29183/95A
Authority: AU
Inventors: Brian Tucker
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-07-18
Filing date: 1995-07-18
Publication date: 1996-02-16
Anticipated expiration: 2015-07-18
Also published as: AU681042B2

Description

"CONVEYOR BELT CLEANING" TECHNICAL FIELD OF THE INVENTION THIS INVENTION relates to conveyor belt cleaning, and it has more particular reference to methods of and means for cleaning residual conveyed material from the conveying surface of a conveyor belt after discharge past the head drum, so that the return run of the belt will be free of residual material.

BACKGROUND ART

Numerous types of apparatus have been devised in the past for the purpose of removing residual conveyed material from conveyor belts, mainly involving the mounting of rigid scraper blades beneath the return run of the belt, but for various reasons these tend to lack the desired degree of efficiency. It has also been proposed to provide a rotating brush system, as disclosed for example in Australian patent specification No.

65951/81 directed to the method of cleaning a conveyor belt which includes the steps of frictionally engaging a roller with the belt so that the roller is caused to be rotated as the belt moves, using rotation of the rotating roller to transmit rotation to rotary brush means, and maintaining the rotating brush means in contact with the belt so that it acts to brush the belt.

However, the means employed for that purpose, as disclosed in the said Australian specification, was so designed and arranged that positive and effective contact of the brush means uniformly across the belt could not be achieved.

OBJECTS OF THE INVENTION

My present invention has been devised to overcome the problems and difficulties currently associated with the cleaning of conveyor belts, and it has for its principal object the provision of novel apparatus which can employ rotating brush means but will be found to be positive in operation at all times while ensuring that uniform pressure is exerted on the belt across the width thereof and without possibility of damage to the belt. In particular the invention aims to provide apparatus of the aforedescribed type which permits the rotating brush means to clean the belt at any selected location after discharge of material from the belt. Other objects of the invention are to provide conveyor belt cleaning apparatus of the kind described which may be made relatively simply and inexpensively; which can be easily mounted adjacent the belt so that all desired adjustments can be achieved for efficient operation, and which will prove strong and durable in use.

DISCLOSURE OF THE INVENTION With the foregoing and other objects in view, my invention resides broadly in rotary belt scraper apparatus of the type for use in cleaning residual conveyed material from the lower surface of the return run of a conveyor belt forming a belt/drum power supply with a head drum mounted rotatably about a set horizontal axis between spaced side frame members of a conveyor main frame, said apparatus including drive wheel means adapted to be rotated about a drive axis transverse to the return run by frictional engagement with said belt/drum power supply when operatively disposed, and a cylindrical cleaning brush adapted to be rotated about a transverse brush axis parallel to that of the drive wheel means for contact with and beneath the return run when operatively disposed relative thereto; characterised in that the ends of the two said axes are constrained by individual bearing means mounted on end beams of a sub-frame, said end beams being rigidly interconnected by side beams of the sub-frame extending across and beneath the return run, the sub-frame having its end beams provided with connector means for releasable attachment to the spaced side conveyor frame members, the parts being so made and arranged that said connector means permit adjustment of the position of each sub-frame end relative to the belt, while the bearing means for the two said axes permit said axes to be set in desired spacing with the brush rotatable operatively by the drive wheel means, the sub-frame being adjustably settable in such selected disposition relative to the return run of the belt that the brush will rotate against the lower surface of the belt in correct contact for cleaning purposes.

In one embodiment, the brush is rotatable by the drive wheel means frictionally engaging end portions of the head drum spaced from the belt edges. However, if so desired the brush is rotatable by the drive wheel means via intermediate drive means driven by said drive wheel means, with the latter frictionally engaging the underside of the return run of the belt downstream of the brush.

Preferably the connector means between the sub-frame and the conveyor main frame members include at each end of the sub-frame one or more mounting rods or tubes rigidly connected to the sub- frame and passing slidably through main frame attachment means so as to provide adjustment for width between the conveyor main frame members. Suitably the connector means has said mounting rod or rods connected to mounting plates having screw-threaded adjustment means for setting the sub-frame in desired disposition. Preferably too, at each end of the sub-frame at least one bearing means has screw-threaded adjustment means for varying the spacing of one said axis from another at that respective end.

It will be appreciated that each said axis is that of a journalled shaft and adjustment means are provided including means for adjusting the distance between the ends of the shafts on the sub-frame, and also means for setting each end of the sub- frame in universal manner on and relative to the respective side frame of the conveyor main frame so that desired frictional engagement of all driven rotary means can be achieved. Other features and advantages of preferred practical design aspects will be hereinafter apparent. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, wherein:-

Fig. 1 shows in schematic side view or side elevation the principal belt-contact and control or treatment components necessary for carrying out one embodiment of the invention, deriving power from the drum itself;

Fig. 2 is an inverted plan view (or view from below in the direction of arrows A-A of Fig. 1) showing the components of Fig. 1 other than the head drum shaft mountings on the conveyor main frame;

Fig. 3 corresponds to Fig. 1 but showing bearing details for the shafts on the sub-frame, the latter being in a modified arrangement to that of Fig. 1;

Fig. 4 is a fragmentary plan view (or view from above in the direction of the arrows B-B of Fig. 3) showing the components of Fig. 3 and certain associated parts;

Fig. 5 shows in schematic end view the details of the friction drive wheel components;

Fig. 6 shows in side elevation the mounting and adjustment details for one end of the sub-frame, viewed in the direction of the side frame means but with the latter omitted;

Fig. 7 shows the components of Fig. 6, viewed in end view and with the components separated;

Fig. 8 shows in perspective view, from above, another embodiment of the invention for deriving power from the return run of the belt;

Figs. 9, 10 and 11 are further views of the embodiment of Fig. 8, and

Fig. 12 shows another embodiment in perspective view. The embodiment shown in Figs. 1 to 7 of the drawings are schematic and illustrative only, the drawings not being to scale or of the same scale between views, while standard components of conventional types have been omitted for the sake of clarity such as the head drum shaft mountings and the side frame means and the rest of the main conveyor frame at each side of and around and along the conveyor. Nevertheless the general appearance of the conveyor belt will be fully understood, any desired belt width being accommodated by the invention, such as normal widths of

450mm, 600mm and 750mm. However, smaller widths such as 350mm or large widths such as 1200mm, present no problems. The apparatus will be designed to clean by brushing across the full width of the belt, and in general there will be a space at each side of the belt between its edge and the main frame, typically one metre approximately so that the components provided by the invention can be simply accommodated.

The conveyor cleaning mechanism illustrated in the drawings will clean residual conveyed material from the conveying surface 30 of a conveyor belt 2 of the type driven by a head drum 1 mounted rotatably about a set axis of rotation 31 between side frame means 32 and 33 of a conveyor main frame 14 at respective sides of the belt 2. A cylindrical synthetic fibre brush 3 (of any resilient and/or flexible brushing material) constitutes a brushing roller mounted on a sub-frame 4 which constitutes the "cleaning mechanism frame", the roller-type cleaning brush 3 being rotatable parallel to the rotation axis 31 of the head drum 1 and at a position adjacent the discharge location as apparent from Fig. 1 for example.

The sub-frame 4 also carries intermediate drive means 34 adapted to be disposed so as to derive power from the head drum 1 when the latter is rotated to drive the belt, using standard componentry (not shown), the drive means 34 in turn transmitting the power to the brushing roller 3, various adjustments being provided, as later described, whereby the sub-frame 4 may be positioned relative to the main frame 14 and the head drum 1 so that the desired operative relationship will be attained for causing the intermediate drive means 34 to derive power from the head drum 1 and in turn cause the brushing roller 3 to rotate against the belt 2 at a position close to the commencement of the return run 35. Preferably the intermediate drive means 34 includes a shaft 8 journalled at its ends on the sub-frame 4 and parallel to the brushing roller 3 which also has a brush shaft 9 journalled at its ends on the sub-frame 4.

The aforementioned adjustment means includes means 19 for adjusting the distance between the ends of the two shafts 8 and 9 on the sub-frame 4, and also means such as components 21, 13, 17 and 18 for enabling each end of the sub-frame 4 to be set in universally adjustable manner on and relative to the side frame means 32 and 33 of the conveyor main frame 14 so that desired frictional engagements of the various aforementioned and other driven rotary components can be achieved.

In addition to the basic features as just described, it will be noted from Fig. 2 that the shaft 8 has at each end a conveyor driven wheel 5, adapted to grip frictionally a brush driven wheel 6 at each end of the brush shaft 9, this view not showing the head drum shaft 7. In the detailed view of Fig. 3, each shaft 8 and 9 is journalled in a bearing block 10 mounted on the sub- frame 4 as apparent in more detail in Fig. 4. Both these views show the driving tension adjuster 19 for moving one bearing block closer or further from the other, bearing mounting bolts 20 being provided as illustrated and adapted to coact with adjustment slots shown in dotted outline at 36 in Fig. 4.

As shown in Figs. 2, 4, 6 and 7, the sub-frame 4 has at each end a mounting plate 11 for securement to the respective side frame member 32 or 33 and adapted to cooperate with an adjusting plate 12 to which it may be adjustably connected by adjuster mounting bolts 13. The plate 12 is connected to a mounting bar 21 in turn connected to the sub-frame 4, and the disposition of the plate 12 relative to the plate 11 is determined by the brush pressure adjustment slot 15, driving pressure adjustment slot 16, driving pressure adjustment screw 17 and brush pressure adjustment screw 18, the method of adjustment being as described hereafter. It will be noted from Figs. 6 and 7 that the adjuster mounting bolts 13 are adjustably movable in the oversize slots 15 and 16 and can be locked by nuts and washers 27. Fig. 5 illustrates the use of rubber or synthetic tyres 22 on metal or alloy centres 23 for the shafts 8 and 9, each having a boss 24 and grub screw 25.

With regard to the method of operation, it will be apparent that the mechanism is designed to use power supplied to the head drum 1 to turn the shaft 8 which has a driving wheel 5 at each end. The drive shaft is in turn friction driven by wheels 6 which are attached to a drive shaft 9 having the cylindrical brush 3, the latter acting to clean the residual material off the returning conveyor belt 2 after discharge of the conveyed materials. The complete mechanism is carried on the mounting frame 4 which can be mounted in any position on the circumference of the conveyor head drum 1, but preferably more or less as illustrated in the drawings close to the position below the material discharge point.

The operating mechanism on the adjustable mounting frame 4 has the two shafts 8 and 9 rotatable in self-aligning bearings carried in the bearing blocks 10, secured to the frame 4 using the bearing mounting bolts 20. The cylindrical synthetic fibre brush 3 is suitably moulded to the cleaning brush shaft 9 which also has two friction driving wheels 6 attached at either end. Thus the brush 3 is rotated by the friction drive wheels 5 which drive the brush driving wheels 6 through the friction caused by the compression of the tyres 22 using the drive tension adjuster 19. Thus the drive energy obtained by rotation of the conveyor head drum 1 during the normal course of operation of the conveyor belt 2 (normally driven by electric motor or other means) is conveyed through the tyres 22 to the rotating brush. Fig. 1 shows the direction of discharge by arrow (a) causing rotation of the drive shaft 8 in the direction of arrow (b), the brush then rotating in the direction of arrow (c). This rotation of the brush 3 combined with the movement of the returning conveyor belt

2 in the direction of arrow (a) causes an intense cleaning action between the brush 3 and the conveyor belt 2, with the resultant cleaned material being discharged from the brush in the direction of arrow (c) towards the main conveyor material discharge (not shown).

The extent of cleaning action can be adjusted on the brush

3 and can be varied to any degree by repositioning the brush 3 closer to or further away from the conveyor belt 2 using the brush adjusters 18 to vary the position of the adjustment plate 12 relative to the "fixed" plate 11, as better understood from the following description of the installation and operation details.

To install the mechanism, the adjustment plate 12 is positioned so that the mounting bolts 13 are in the centre of or slightly below the centre of the pressure adjusting slots 15 and 16 on both ends of the mechanism. The nuts on the washers 27 on the adjusting mounting bolts 13 on both ends are then tightened just sufficiently to hold the mechanism in place. The next step is to tack weld or bolt the mounting plate 11 to the conveyor frame 14 so that the sub-frame 4 is parallel to the head drum 1, with the cleaning brush 3 just below the conveyor belt 2 and with the wheels 5 just making contact with the head drum 1. The mechanism can then be checked for correctness of position of all axes of rotation and the final position on the conveyor frame 14 is then secured by welding or bolting the mounting plate 11 to its respective frame member 14. The operator can then loosen the nuts 27 on the bolts 13 and turn the pressure adjuster 17 clockwise until firm pressure is made with the surface of the head drum 1 on both sides. Slightly more than finger tight securement should be sufficient, there being no need to compress the tyre 22 against the head drum 1. The pressure adjuster 18 is then turned clockwise until the cleaning brush 3 just makes contact with the surface of the conveyor belt 2 on both sides. Only a light pressure is required and the cleaning brush should not be jammed tightly against the conveyor belt 2. The cleaning mechanism is then ready to run once the nuts 27 have been tightened on all adjuster mounting bolts.

Following installation as above, the operator can render the conveyor operative and observe the action and rotation of the wheels 5 and the cleaning brush 3 to ensure sufficient driving force on the driving wheels 5 to keep the cleaning brush 3 rotating evenly while brushing the conveyor belt 2 lightly but with sufficient force to ensure that the conveyor belt 2 is cleaned. Should the mechanism be operating smoothly, normal operation can be resumed. However, should the driving force on the driving wheels 5 or the tension on the cleaning brush 3 need adjustment, it is a simple matter to loosen the nuts 27 on the adjusting plates 12 and readjust using the driving pressure adjusters 17 and/or the cleaning brush adjusters 18. Retightening of the nuts 27 is then effected and when the conveyor is restarted there should be smooth operation of the driving wheels 5 and cleaning brush 3.

Turning now to the embodiment of Figs. 8 to 11, the apparatus 50 in this case is illustrated without the conveyor belt or the head drum, and the drive wheel means 51 makes frictional contact with the return run instead of with the head drum as in the earlier embodiment. The drive wheel means 51 includes a shaft 52 having an axis 53 and fitted with contact drums 54 separated by a ribbed drive pulley (not shown) in a cover 55 so as to rotate an intermediate shaft 56 fitted at its ends with engagement wheels 57 to engage similar wheels 58 on a brush shaft 59 having an axis 60, the brush being indicated at 61. The said axes are constrained by individual bearing blocks 62 mounted on end beams 63 of a sub-frame 64, the end beams 63 being rigidly interconnected by side beams 65 extending across and beneath the return run, adjuster means 66 being provided on the bearing blocks 62 for varying the axis positions. At each end of the sub-frame 64 there are provided connector means 67 including in this case a pair of rods 68, adjustably connected as to length in mounting plates 69 for attachment to the frames with screw-threaded means 70 as indicated. Thus there are both drive adjuster nuts and brush adjuster bolts as illustrated, while mounting bolts may be passed directly through the conveyor frame.

In installing this embodiment, the operator ensures that the conveyor belt is tracking correctly and adjustments are made if necessary before the scraper apparatus is installed, the apparatus being able to be mounted at any position along the length of the return run of the belt. With the scraper below the return belt the drive adjuster bolt is used to bring the drive wheel up into contact with the belt. It is not necessary to have excessive pressure exerted on the drive wheel, and the belt should just rest on the wheels with minimal contact sufficient to drive the scraper. The drive adjuster nuts are then tightened slightly to hold the scraper in position to adjust the brush position, and the brush adjuster bolt is used to bring the brush up to a position just below the lower surface of the belt. The operator then starts the conveyor belt and brings the brush up until the minimum pressure required to achieve the desired level of cleaning has been reached. The brush must merely sweep the material off the belt and it is not designed to scrub the belt. Excessive brush pressure will cause the drive mechanism to generate excessive heat internally in the drive wheels and this will lead to their destruction. Finally when the desired clamping level has been achieved all adjuster bolts are tightened and locked in position. The scraper is now ready for continuous operation and will require minimal brush adjustment to compensate for wear to operate efficiently.

The third embodiment shown in Fig. 12 has similar features to that of the second embodiment except that the intermediate shaft is dispensed with and the drive wheel means 51a directly drives the brush shaft 59a. Other items are given corresponding numerals as illustrated.

The several embodiments have been given to illustrate that many modifications of constructional detail and design may be effected and it will be apparent that the invention embraces such modifications as lie within its broad scope and ambit as defined by the appended claims.

Claims

1. Rotary belt scraper apparatus of the type for use in cleaning residual conveyed material from the lower surface of the return run of a conveyor belt forming a belt/drum power supply with a head drum mounted rotatably about a set horizontal axis between spaced side frame members of a conveyor main frame, said apparatus including drive wheel means adapted to be rotated about a drive axis transverse to the return run by frictional engagement with said belt/drum power supply when operatively disposed, and a cylindrical cleaning brush adapted to be rotated about a transverse brush axis parallel to that of the drive wheel means for contact with and beneath the return run when operatively disposed relative thereto; characterised in that the ends of the two said axes are constrained by individual bearing means mounted on end beams of a sub-frame, said end beams being rigidly interconnected by side beams of the sub-frame extending across and beneath the return run, the sub-frame having its end beams provided with connector means for releasable attachment to the spaced side conveyor frame members, the parts being so made and arranged that said connector means permit adjustment of the position of each sub-frame end relative to the belt, while the bearing means for the two said axes permit said axes to be set in desired spacing with the brush rotatable operatively by the drive wheel means, the sub-frame being adjustably settable in such selected disposition relative to the return run of the belt that the brush will rotate against the lower surface of the belt in correct contact for cleaning purposes.

2. Rotary belt scraper apparatus according to Claim 1, wherein the brush is rotatable by the drive wheel means frictionally engaging end portions of the head drum spaced from the belt edges.

3. Rotary belt scraper apparatus according to Claim 1, wherein the brush is rotatable by the drive wheel means via intermediate drive means driven by said drive wheel means, with the latter frictionally engaging the underside of the return run of the belt downstream of the brush.

4. Rotary belt scraper apparatus according to any one of the preceding claims, wherein the connector means between the sub- frame and the conveyor main frame members include at each end of the sub-frame one or more mounting rods or tubes rigidly connected to the sub-frame and passing slidably through main frame attachment means so as to provide adjustment for width between the conveyor main frame members.

5. Rotary belt scraper apparatus according to any one of the preceding claims, wherein the connector means has said mounting rod or rods connected to mounting plates having screw-threaded adjustment means for setting the sub-frame in desired disposition.

6. Rotary belt scraper apparatus according to any one of the preceding claims, wherein at each end of the sub-frame at least one bearing means has screw-threaded adjustment means for varying the spacing of one said axis from another at that respective end.

7. Rotary belt scraper apparatus according to Claim 1, wherein each said axis is that of a journalled shaft and adjustment means are provided including means for adjusting the distance between the ends of the shafts on the sub-frame, and also means for setting each end of the sub-frame in universal manner on and relative to the respective side frame of the conveyor main frame so that desired frictional engagement of all driven rotary means can be achieved.

8. Apparatus for use in cleaning residual conveyed material from the conveying surface of a conveyor belt of the type driven by a head drum mounted rotatably about a set axis between side frame means of a conveyor main frame; characterised by the provision of a resilient or flexible brushing roller of substantially cylindrical form mounted on a sub-frame for rotation parallel to the head drum axis and at a position adjacent the discharge location; said sub-frame also carrying intermediate drive means adapted to be disposed so as to derive power from the belt/drum power source assembly and transmit same to the brushing roller, adjustment means being provided whereby said sub-frame may be so positioned relative to the main frame, the head drum and the belt, that the desired operative relationship will be attained for causing the intermediate drive means to derive power from the power source head drum/belt assembly and in turn cause the brushing roller to rotate against the belt at or prior to commencement of its return run, the brushing roller being set for uniform contact with the belt parallel to the axes of rotation.