GB2324287A

GB2324287A - Aligning means for a conveyor belt

Info

Publication number: GB2324287A
Application number: GB9707574A
Authority: GB
Inventors: Danielle Neves Neo; Freitas Neto Fidelis Luiz De; Dione Luiz Oliveira; Adailson Jose Nolasco; Marcelo Aguiar Duarte; Carlos Augusto Rodrigues
Original assignee: Companhia Vale do Rio Doce
Current assignee: Vale SA
Priority date: 1995-08-03
Filing date: 1997-04-15
Publication date: 1998-10-21
Anticipated expiration: 2017-04-15
Also published as: GB9707574D0; BR9503602A; GB2324287B

Abstract

An aligning means for a conveyor belt comprises sensing rollers 1 for monitoring the edges of the belt 8 and producing signals to operate valves 3 for actuating a pneumatic ram 2 to pivot a roller 7 relative to the belt 8, such movement of the roller 7 bringing the belt 8 into a central position on the roller 7. Alternatively, the belt may be centered by rollers acting on its edges.

Description

SELF ALIGNING PNEUMATIC BRACKET The present invention relates to a self aligning pneumatic bracket1 and more specifically, an improvement in the design of a self aligning pneumatic bracket for conveyor belts.

Technical experts in this field are well aware of the fact that conventional brackets employed to correct the alignment of conveyor belts on their supporting rollers are inefficient in their performance to maintain the belts centrally aligned in relation of the conveyors.

Conventional fixed rollers with vertically extending axes are often attached to the conveyor's structure to the sides of the conveyor belt's normal position in order to limit any error or deviation of the alignment of the belt in relation to the conveyor's structure.

The deficiency inherent in this self alignment system does not eliminate the inadequate sitting of the belt on its bed, and thereby causing its dynamic misalignment and the consequent falling off of the conveyed materials.

Another consequence due to the belt's misalignment in relation to the conveyor's structure is due to the fact that wear occurs at the edges of the belt which engage with the rollers, which substantially reduces the belt's useful life.

The purpose of the present invention is to provide a self aligning pneumatic bracket that efficiently maintains a conveyor belt centrally aligned relative to the supporting rollers of the conveyor.

Another purpose of the present invention is to provide a self aligning pneumatic bracket which can correct the smallest error or deviation noted in the alignment of the belt relative to the conveyor's structure.

Another purpose of the present invention is to provide a self aligning pneumatic bracket which maintains the belt permanently and adequately seated on its bed, thereby eliminating its dynamic misalignment and the resulting falling from the belt of the conveyed materials.

Another purpose of the present invention is to provide a self aligning pneumatic bracket1 which avoids wear of the edges of the belt, thus increasing its useful life considerably, as compared to conventional guides.

The present self aligning pneumatic bracket was developed in order to fulfil these objectives, which provides the continuous alignment of the belt on its bed, by assuring a faster and more efficient alignment, improving the operative capacity of the conveyors, reducing the labour costs and the loss of material.

These and other objectives of the present invention are achieved with the self aligning pneumatic bracket consisting of a framed structure, which is deployed around the conveyor belt and installed adjacent to the return roller, the Structure being framed sideways and provided with misalignment switches, which detect and inform the misalignment through signals and a "PCL", which in tum interprets the said signals and controls a set of solenoids of the directional valves, which in its tum release compressed air into a pneumatic cylinder that corrects the self aligning bracket and thereby, conducting the belt to return to its normal bed.

According to a second aspect, an apparatus for maintaining alignment of a belt conveyor running over a return roller comprises a pair of sensors positioned to detect the edges of the belt after it exits the return roller, control means receiving sensing outputs from the sensors, and correction means controlled by the control means and acting on the belt to exert lateral force on the belt as it approaches the return roller. The correction means may comprise a second roller extending generally transversely to the belt and frictionally engaging it, and an actuator associated with the second roller and operated by the control means, the arrangement being such that the second roller may, under the action of the actuator, swing about an axis perpendicular to the plane of the belt.

Alternatively, the correction means may comprise a pair of guide rollers, each capable of engaging a respective edge of the belt to apply a lateral force thereto.

Embodiments of the invention will now be described in detail, with reference to the accompanying drawings, in which: Figure 1 represents a schematic and perspective view of the self aligning pneumatic bracket; Figure 2 represents a front and schematic view of the self aligning pneumatic bracket, showing the belt in a misaligned position in relation to the conveyor's structure; Figure 3 represents, in perspective, a detail of the pneumatic cylinder constituting the self aligning pneumatic bracket; Figure 4 represents a detail in perspective of the positioning of the inductive sensors adjacent to the conveyor belt's structure; Figure 5 represents a detail in perspective of the directional valves and solenoids making up the self aligning pneumatic bracket; Figure 6 represents a detail in perspective of the misalignment switch comprising the self aligning pneumatic bracket; and Figure 7 represents an enlarged view in detail and perspective of the self aligning pneumatic bracket, mounted adjacent to the conveyor belt's structure.

In accordance with the Figures, the self aligning pneumatic bracket of the present invention, consists of two misalignment or detector switches 1, one on each side of the conveyor belt's structure 8; at least one pneumatic cylinder 2; two directional air valves 3; three drainage regulating valves 3a; two solenoids 4; three sensors 5 their purpose being to inform the position of the bracket (left, right or centre) this information being monitorized and registered; one self aligning bracket 7.

Referring to Figure 1, there is seen a belt 8 running over a roller 7, the edges of the belt engaged by a pair of sensing rollers 1 which detect the edges of the belt. A pneumatic ram 2 is controlled by air valves 3, which extend and contract the ram to control the position of the roller 7, which in turn causes the position of the belt to be adjusted in the direction transverse to the length of the belt.

In Figure 2, The belt 8 is seen displaced to the left with respect to the roller 7, and contacts the sensing roller 1. This causes a signal to be sent to operate the valves 3 and the ram 2, so that the roller 7 is repositioned to bring the belt back to a central position on the roller 7.

The ram 2 may act on the roller 7 to incline its axis of rotation with respect to transverse direction of the belt 8, so that the roller exerts a sideways force on the belt as it runs over the roller.

Alternatively the ram 2 may urge a guide roller, whose axis extends generally vertically, into engagement with an edge of the belt to move the belt laterally.

In this manner, the belt conveyors which are provided with self aligning pneumatic brackets develop a higher conveying speed and a significant reduction in the loss of material due to falling off.

The operation of the self aligning pneumatic bracket is activated by using the electrical signal of the belt's misalignment switch 1, which instead of interrupting it, activates an electronic control circuit to control the extension and retraction of a pneumatic cylinder 2, which in its turn performs the necessary adjustments on structure 6 and 7, carrying the belt back toward its normal bed. Although this self aligning pneumatic bracket has been described and illustrated as an electro-pneumatic device, there are other options of designs, such as an electro-hydraulic or electrical electronic device, which can be built without departing from the purpose of the present invention.

Specifically, a hydraulic or electric actuator can be used in place of the ram 2. It is also foreseen that the device can be installed on any other type of roller or bracket, as well as on conveyors of various widths.

Claims

1. A self aligning pneumatic bracket comprising two misalignment switches 1; one on each side of the belt conveyor's structure; by at least one pneumatic cylinder 2; two directional valves 3; two solenoids 4; three sensors 5; one self aligning bracket or framed structure 6; one self aligning roller 7.

2. An apparatus for maintaining alignment of a belt conveyor running over a return roller, comprising a pair of sensors positioned to detect the edges of the belt after it exits the return roller, control means receiving sensing outputs from the sensors, and correction means controlled by the control means and acting on the belt to exert lateral force on the belt as it approaches the return roller.

3. An apparatus for maintaining alignment of a belt conveyor running over a return roller according to claim 2, wherein the correction means comprises a second roller extending generally transversely to the belt and frictionally engaging it, and an actuator associated with the second roller and operated by the control means, the arrangement being such that the second roller may, under the action of the actuator, swing about an axis perpendicular to the plane of the belt.

4. An apparatus for maintaining alignment of a belt conveyor running over a return roller according to claim 2, wherein the correction means comprises a pair of guide rollers, each capable of engaging a respective edge of the belt to apply a lateral force thereto.

5. An apparatus for maintaining alignment of a belt conveyor running over a return roller substantially as herein described, with reference to any of Figures 1 to 6 of the accompanying drawings.