Scraper for belt conveyor and mounting arrangement for scraper blade

Abstract: A conveyor scraper which includes support structure (12;42;124), scraper blade means (14;18) which is mounted to the support structure and which is movable to a limited extent relatively to the support structure, and biasing means (24;48;84;84A) which acts directly or indirectly between the support structure and the scraper blade means.

Description: This invention is concerned generally with the mounting of a conveyor scraper relatively to a conveyor belt. A conveyor scraper, during use, should be able to move in a vertical sense relatively to the direction of movement of a conveyor belt with which the scraper is engaged in order to allow for movement of the belt to ensure that the scraper is retained in scraping engagement with the belt surface. Such an arrangement is shown in German Gebrauchsmuster G 9405735.4 which shows a conveyor scraper comprising a support structure, a scraper blade means and a resilient biasing means, the biasing means being mounted to the support structure and which is movable to a limited extent relatively to the support structure and which urges the scraper blade means in a first direction towards a surface to be cleaned and ensures that an edge of the scraper blade means is retained in scraping contact with the surface. This type of vertical movement is also necessary to compensate for wear of the scraper blade which arises due to the abrading action of the conveyor belt surface on the scraper. In practice, however, horizontal movement, i.e. a lateral deflection of the scraper blade, must also be provided for at least to a limited extent and this aspect of lateral deflection is shown in US 5310042. It is possible to adjust a scraper blade, at periodic intervals, using manual techniques, to compensate for scraper blade wear. Again such an arrangement is shown in US 5310042. On the other hand, it is preferable to have an automatic means of compensating for such wear. The invention achieves the combined movement of the conveyor scraper in use in a vertical sense relative to the direction of movement of a conveyor belt together with the desirable lateral deflection of the scraper blade by ensuring that the scraper blade means includes a resiliently deformable mounting with at least one formation which is engageable with a scraper blade which extends from the mounting and enablimg that the blade to move in at least one direction which is transverse to the first direction with deformation of the mounting. The biasing means may take on any suitable form and may, for example, comprise at least one spring, torsion member, or any equivalent device. The biasing means may be engaged with a formation on the scraper blade means. The formation may be of any appropriate kind and, for example, may comprise a slot or similar formation which at least partially accommodates the biasing means. In a different form of the invention, the biasing means may act in a piston and cylinder assembly. For example, the biasing means may act on a piston and cylinder assembly wherein the piston is engaged with the cylinder and is movable relatively thereto with at least one attachment formation being provided to enable the scraper blade means to be attached directly or indirectly to the piston or the cylinder. In a preferred form of the invention, the scraper blade means is fixed to an extension of the piston. The biasing means may, for example, comprise a spring which extends circumferentially around the piston and which acts between the cylinder and a formation on the piston. The cylinder may be mounted for movement relatively to support structure so that the position of the cylinder may be adjusted towards or away from a conveyor belt. For example the support structure may include a threaded socket and the cylinder may be threadedly engaged with the socket. A protective shroud may be provided to prevent the ingress of dirt or foreign material between opposing relatively slidable surfaces of the cylinder and the piston. The scraper blade means may include a scraper blade which is mounted on a resilient mounting and the biasing means may act between the support structure and the mounting. The biasing means may be constrained to act in a vertical direction. The stiffness of the biasing means may be less than the stiffness of the mounting so that the biasing means may compress before the mounting compresses. The mounting may be designed to deflect laterally. The mounting may include a block which includes one or more formations each of which is respectively adapted to receive biasing means. The invention also provides a scraper assembly for use in a conveyor scraper which includes a scraper blade and a mounting with a body which is formed from a resiliently deformable material and in which is formed a passage and which is characterised in that the body has a first slot formation at one end in which an edge of the scraper blade is located and a second slot formation at an opposed end whereby the body is attachable to fixed structure, and in that the passage is between the first and second formations and encourages resilient flexing of the body about the passage in a lateral sense relatively to a line extending between the first and second formations. The invention is further described by way of examples with reference to the accompanying drawings. In the drawings in detail: Figure 1 is a view from below of a block for use in a scraper assembly according to the present invention, Figure 2 is a cross-sectional side view of the block shown in Figure 1, Figure 3 is a cross-sectional end view of the block, Figure 4 is a cross-sectional side view of a mounting to which the block of Figures 1 to 3 is attached, Figure 5 is a side view, partly sectioned, illustrating the use of the mounting as shown in Figure 4, Figure 6 is a cross-sectional plan view through the arrangement shown in Figure 5, and Figure 7 is a side view of a lower end of a modified mounting and a fixing arrangement for the mounting. Figures 1 to 3 illustrate a block 70 which is moulded from a suitable plastics material and which includes an internal slot 72 with vertically extending enlarged circular recesses 74 and 76 respectively. Two holes 78 and 80 respectively extend transversely through the block. The block 70 is mounted to a base 82 of a resilient mounting or torsion element 84, see Figure 4. The mounting has a body which is formed from a resiliently deformable plastics material e.g. rubber or polyurethane with a passage 86 which may be offset slightly from a centre line of the body. The passage forms a zone of weakness which encourages resilient flexing of the mounting about the passage in a transverse or lateral sense, relatively to a line extending between its opposed upper and lower ends. At its upper end the mounting has a slot 88 in which is moulded an insert 90. A scraper blade, not shown, is in use of the mounting located inside the insert. The blade extends from the mounting in an upwards direction. In an alternative arrangement the block 70 is moulded into and is directly bonded to the buffer 84. Figure 5 shows a mounting plate 92 which is fixed to a mounting bar or tube 94 of a conveyor scraper assembly. A plurality of similar mounting plates are fixed to the bar in line extending in the longitudinal sense of the bar. The plate 92 has vertically aligned slots 96 and 98. Figure 6 is a plan view, partly sectioned, of the assembly shown in Figure 5 with the mounting 84 attached to the plate 92. Spacers 100 and 102 are positioned in the slots 96 and 98. The enlarged recesses 74 and 76 of the block 70 house coil springs 104 and 106 respectively. It is possible to push the mounting downwardly onto the plate 92 and compress the springs 104 and 106 fully. The mounting is fixed to the plate 92 by means of bolts, not shown, which pass through the slots 96 and 98 and the respective spacers 100 and 102. The bolts keep the mounting captive on the plate 92 but permit the mounting to move vertically up or down within the constraint imposed by the slots 96 and 98. A scraper blade, not shown, is mounted in the slot 88 and the insert 90 of the mounting. As the blade wears during use the springs 104 and 106, which are constantly under compression, extend vertically and urge the mounting upwardly to compensate for the wear of the blade. If a lateral force is exerted on the mounting, due for example to an irregularity which is on the conveyor belt surface and which impacts the blade, then the mounting is able to deflect in a lateral sense due to the weakened zone created by the passage 86 in the body of the mounting. In an alternative arrangement the scraper blade is moulded into and is directly bonded to the mounting 84. The assembly shown in Figures 4 and 5 is capable of vertical adjustment to compensate for wear of the scraper blade and, when required, can deflect laterally. Figure 7 illustrates, on an enlarged scale, the lower end of a modified mounting 84A which in many respects is similar to the mounting shown in Figure 4. The mounting is attached to a support plate 120 which is attached by means of welding 122 to a support tube 124. An insert 126 is located inside a cavity 128 on a lower side of the mounting. The insert may be bonded to the mounting 84A. A catch member 130 is located inside a passage 132, formed inside the insert, and is biased to the left in the drawing by means of a coil spring 134. The catch member has a sealing plate with a rupture disk 136 at its left hand end in the drawing. The support plate 120 has an elongate slot 138 which is similar to the slots 96 and 98 shown in Figure 5 and which permits vertical movement of the mounting 84A relatively to the mounting plate, under the action of one or more springs, not shown. It is to be noted that an opening 140 in a base of the mounting 84A does not permit the catch member 130 to be removed, by horizontal sliding movement, as is the case with the bolts which are used in the slots 96 and 98. On the other hand the opening 140 does provide access to the sealing plate and rupture disk. When the mounting is to be mounted to the support plate the upper edge of the support plate is advanced into an elongate slot 142 which is formed in the insert 126 and which is similar to the slot 72 shown in Figure 1 The catch member 130 is then deflected to the right, against the biasing action of the spring 134, to permit this movement. Once the left hand end of the catch member reaches the slot 138 the spring biases the catch member to the left in the drawing and the catch member then engages, with a snap action, with the left hand portion of the passage 132 in the insert. The catch member secures the mounting to the support plate in such a way that the mounting is capable of relative vertical movement in a manner which is analogous to what has been described hereinbefore with reference to Figures 2 to 6. When the scraper blade which is mounted to the mounting is worn, or if for any other reason it becomes necessary to remove the mounting from the support plate, then by making use of a sharp instrument which is inserted into the opening 140 it is possible to fracture or break the rupture disk 136 and depress the catch member 130 thus releasing it. The mounting can then be removed from the support plate. The arrangement thus makes it possible for a mounting to be removed, using only one tool, and for a new mounting to be installed, without using any tools. The piston 46 can also move downwardly, with the spring 46 being further compressed, to allow for vertical downwards movement of the belt which may occur due to a variety of reasons. Vertical movement of the piston is guided by the washer 50 which slides inside the cylinder 44. Further, as has been noted, the vertical position of the cylinder can be adjusted periodically by rotating the cylinder in the socket 40 to provide a further means, in this case manual, for allowing for adjustment to compensate for wear of the scraper blade. Turning now to an illustrative embodiment in accordance with the invention, Figures 4 to 6 illustrate a block 70 which is moulded from a suitable plastics material and which includes an internal slot 72 with vertically extending enlarged circular recesses 74 and 76 respectively. Two holes 78 and 80 respectively extend transversely through the block. The block 70 is mounted to a base 82 of a resilient mounting or torsion element 84, see Figure 7. The mounting has a body which is formed from a resiliently deformable plastics material e.g. rubber or polyurethane with a passage 86 which may be offset slightly from a centre line of the body. The passage forms a zone of weakness which encourages resilient flexing of the mounting about the passage in a transverse or lateral sense, relatively to a line extending between its opposed upper and lower ends. At its upper end the mounting has a slot 88 in which is moulded an insert 90. A scraper blade, not shown, is in use of the mounting located inside the insert. The blade extends from the mounting in an upwards direction. In an alternative arrangement the block 70 is moulded into and is directly bonded to the buffer 84. Figure 8 shows a mounting plate 92 which is fixed to a mounting bar or tube 94 of a conveyor scraper assembly. A plurality of similar mounting plates are fixed to the bar in line extending in the longitudinal sense of the bar. The plate 92 has vertically aligned slots 96 and 98. Figure 9 is a plan view, partly sectioned, of the assembly shown in Figure 8 with the mounting 84 attached to the plate 92. Spacers 100 and 102 are positioned in the slots 96 and 98. The enlarged recesses 74 and 76 of the block 70 house coil springs 104 and 106 respectively. It is possible to push the mounting downwardly onto the plate 92 and compress the springs 104 and 106 fully. The mounting is fixed to the plate 92 by means of bolts, not shown, which pass through the slots 96 and 98 and the respective spacers 100 and 102. The bolts keep the mounting captive on the plate 92 but permit the mounting to move vertically up or down within the constraint imposed by the slots 96 and 98. A scraper blade, not shown, is mounted in the slot 88 and the insert 90 of the mounting. As the blade wears during use the springs 104 and 106, which are constantly under compression, extend vertically and urge the mounting upwardly to compensate for the wear of the blade. If a lateral force is exerted on the mounting, due for example to an irregularity which is on the conveyor belt surface and which impacts the blade, then the mounting is able to deflect in a lateral sense due to the weakened zone created by the passage 86 in the body of the mounting. In an alternative arrangement the scraper blade is moulded into and is directly bonded to the mounting 84. The assembly shown in Figures 7 and 8 is capable of vertical adjustment to compensate for wear of the scraper blade and, when required, can deflect laterally. Figure 10 illustrates, on an enlarged scale, the lower end of a modified mounting 84A which in many respects is similar to the mounting shown in Figure 7. The mounting is attached to a support plate 120 which is attached by means of welding 122 to a support tube 124. An insert 126 is located inside a cavity 128 on a lower side of the mounting. The insert may be bonded to the mounting 84A. A catch member 130 is located inside a passage 132, formed inside the insert, and is biased to the left in the drawing by means of a coil spring 134. The catch member has a sealing plate with a rupture disk 136 at its left hand end in the drawing. The support plate 120 has an elongate slot 138 which is similar to the slots 96 and 98 shown in Figure 8 and which permits vertical movement of the mounting 84A relatively to the mounting plate, under the action of one or more springs, not shown. It is to be noted that an opening 140 in a base of the mounting 84A does not permit the catch member 130 to be removed, by horizontal sliding movement, as is the case with the bolts which are used in the slots 96 and 98. On the other hand the opening 140 does provide access to the sealing plate and rupture disk. When the mounting is to be mounted to the support plate the upper edge of the support plate is advanced into an elongate slot 142 which is formed in the insert 126 and which is similar to the slot 72 shown in Figure 4. The catch member 130 is then deflected to the right, against the biasing action of the spring 134, to permit this movement. Once the left hand end of the catch member reaches the slot 138 the spring biases the catch member to the left in the drawing and the catch member then engages, with a snap action, with the left hand portion of the passage 132 in the insert. The catch member secures the mounting to the support plate in such a way that the mounting is capable of relative vertical movement in a manner which is analogous to what has been described hereinbefore with reference to Figures 5 to 9. When the scraper blade which is mounted to the mounting is worn, or if for any other reason it becomes necessary to remove the mounting from the support plate, then by making use of a sharp instrument which is inserted into the opening 140 it is possible to fracture or break the rupture disk 136 and depress the catch member 130 thus releasing it. The mounting can then be removed from the support plate. The arrangement thus makes it possible for a mounting to be removed, using only one tool, and for a new mounting to be installed, without using any tools.

Claims: A conveyor scraper comprising a support structure (124), a scraper blade means and a resilient biasing means (104; 106), the biasing means being mounted to the support structure and which is movable to a limited extent relatively to the support structure and which urges the scraper blade means in a first direction towards a surface to be cleaned, and characterised in that the scraper blade means includes a resiliently deformable mounting (84; 84A) with at least one formation which is engageable with a scraper blade which extends from the mounting and enabling the blade to move in at least one direction which is transverse to the first direction with deformation of the mounting. A scraper according to Claim 1, characterised in that the resilient biasing means includes at least one spring (104; 106). A scraper according to Claim 1 or 2, characterised in that the support structure (124) includes a mounting plate in which is formed at least one slot (138; 96; 98) and a fixing device which is engaged with the slot and the scraper blade means and which is movable along the slot relatively to the mounting plate. A scraper according to Claim 3, characterised in that the fixing device includes releasable catch means (130) which secures the scraper blade means to the mounting plate with a snap action. A scraper according to Claim 1 or 2, characterised in that it includes a piston and cylinder assembly and wherein the resilient biasing means acts between the piston and the cylinder, and the scraper blade means is fixed to the piston and the cylinder is mounted to the support structure. A scraper according to Claim 5, characterised in that the cylinder is mounted for movement relatively to the support structure to adjust the position of the scraper blade means relatively to the support means. A scraper according to any one of Claim 1 to 6, characterised in that the resilient mounting is formed from a resilient material with a zone of weakness (86) which promotes the transverse resilient deformation.

Inventors: BRINK AREND JACOBUS, BRINK, AREND JACOBUS
Applicants: SCORPIO CONVEYOR PRODUCTS PROP, SCORPIO CONVEYOR PRODUCTS (PROPRIETARY) LIMITED
Application year: 1998
Main classification: B65G45
IPC codes: B65G45