GB2333275A - Guide roller for conveyor belts - Google Patents

Abstract

A guide roller 5 for conveyor belts 4 has a pair of flanges 9, arranged coaxially on the corresponding outer surface of a sleeve 6, able to slide axially and rotate along/around the sleeve independently of each other; flexibly yielding springs 13 operate on each flange 9, to maintain said flanges facing each other and reciprocally in contact in a neutral, non operating end position in which the flanges 9 cover the outer surface of the sleeve 6. The flanges 9 are able reciprocally to move away from each other axially along a direction that is parallel to a longitudinal axis (x) of the roller 5 and in opposite directions at the point of contact with the belt 4 and with the possibility of rotating independently, in order to allow the flanges 9 and sleeve 6 gradually to rotate according to the surface area of the belt (4) in contact with the guide roller 5.

Description

Guide roller for conveyor belts The present invention relates to a guide roller for application on conveyor belts. This general statement signifies use of a belt, which is initially flat, closed in a loop, and forming two branches, an active conveying branch and a passive return branch. Said guide roller can be used for a wide range of applications such as: cavity conveyor belts used in plants for loading/unloading bulk material, sacks, etc; flat belt conveyors used mainly for conveying packed loads; machines in which belt movement is used, e.g. for testing components designed for rolling, such as wheels, and rollers, or to obtain machining or testing of non moving pieces (for example, polishing, testing of abrasion resistance).

In the present description, with the sole purpose of providing examples, reference will be made to the above mentioned conveyor belts used in systems calling for loading bulk material at one point and unloading said material at another point, without ''C thereby limiting the scope of the invention in other fields.

These conveyor belts have a standard configuration comprising a conveying station consisting of a set of rollers deployed in groups of three at a prearranged distance from each other thus to form a branch (the upper active branch) of the conveying station, whereas a subsequent set of rollers, parallel to each other, is located under the previous set and performs as the return branch of the station.

The rollers support the two branches of material transport conveyor belt, which is often equipped with slats for moving the material and is usually closed in a loop around two end rollers, which are usually motor driven, and runs on the outer surface of the roller.

Each of the above mentioned rollers consists of a cylindrical element or sleeve freely rotating around its longitudinal axis, to thus facilitate the movement of the belt, and is supported by a relevant shaft projecting from the end of the sleeve thus allowing it to be associated with a bilateral support structure forming the lateral areas of the conveying station.

The above mentioned three-roller groups consist of three different rollers, one of which is central and at a horizontal axis, and two rollers, bilateral with respect to the first and deployed according to a longitudinal axis angled with respect to the first roller in order to form a concave profile for supporting the belt.

Guide rollers, also in groups of three, uniformly distributed along the active branch, are used to prevent lateral wandering of the belt and possible egress of the belt from the cavity formed by the three previous rollers: these guide rollers, which have a similar structure to the previous rollers, are associated at the outer ends of the support structure and are located perpendicularly with respect to the corresponding bilateral angled rollers, in order partly to face the belt inside the cavity.

This special solution for the guide rollers has not proved particularly efficient, because these rollers are not always capable of containing the wandering movements of the belt due also to vibrations caused by the slats skipping as they pass over the return branch: in fact, the belt moves at high speed, whereas the guide roller is basically motionless unless, as it wanders, the belt comes into contact with the roller.

The difference in speed between the belt and the guide roller which, as it is motionless at time of contact with the belt, requires some time to reach its peripheral speed, causes temporary friction between belt and roller which can cause: rapid wear of the roller and, to a certain extent, of the belt; rapid failure of the roller thus creating cutting profiles that may cut the belt and, lastly, the belt moving above the guide roller.

The purpose of the present invention is, therefore, to eliminate the problems mentioned above by providing a guide roller which can compensate the speed between roller and belt, ensure quicker return of the belt into its correct conveying position, without, however, overly altering the simple, economic structure of the roller.

The technical characteristics of the invention according to the above mentioned purposes are described in the claims below and the advantages of the invention can be evinced from the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention and in which: - figure 1 shows, in a schematic front view, part of the belt-aided conveying station equipped with three-roller groups constituting an active branch of the conveyor belt provided with guide rollers conforming to the present invention; - figure 2 is a front view, partially in crosssection and in a larger scale compared to figure 1, of the guide roller disclosed by the present invention; - figure 3 shows a detail of a flat conveyor belt equipped with the guide roller disclosed by the present invention, in a schematic front view with some parts cut away.

With reference to the accompanying drawings, especially figure 1, the guide roller in question can be used on conveyor belts generally consisting of a belt 4, initially flat, closed in a loop on at least one pair of drums (not shown here as they are a well known type and not strictly part of the invention), which drive and support the belt 4 thus forming two branches: an active conveying branch 3 and a passive return branch.

In the remainder of the description, purely as an example, we shall refer to a conveyor belt for loading-unloading bulk material (for example, gravel), with the belt 4 possibly equipped with slats for pushing the material; obviously, this description does not limit the inventive scope of the solution, which can be used also on other types of conveyor belts performing functions other than those described here.

Conveyor belts of the type mentioned above include, amount other things, a first set 1 of rollers 2 arranged at established distances from each other to form a support and transit surface of the active conveying branch 3 of the belt 4. The latter is closed in a loop and extends, with the second return-branch, along a second surface consisting of a second set of rollers (not shown here, as they are a well known type and not strictly part of the invention), parallel to each other and located under the previous rollers 2.

In the above mentioned first set 1 of rollers 2, there is a three-roller group, labelled 2a, 2b and 2c, consisting of a first horizontal roller 2a, and a pair of rollers 2b and 2c which are angled with respect to the first 2a and arranged as bands opposing the first horizontal roller: in this way, jointly with the upper generators, a cavity-shaped profile is formed.

Three-roller groups are described in these solutions, but sets of single rollers (see figure 3) may also be used for the active branch, or sets of roller pairs inclined with respect to each other to form a "V" profile without the solution losing its originality.

As can be seen in figure 1, one or more of these three-roller groups 2a, 2b and 2c have a pair of guide rollers 5 for controlling any partial sideways, or even vertical, wandering of the belt 4.

These guide rollers 5 are associated at the free end of the corresponding angled rollers 2b and 2c and are inclined with respect to the latter, so that they may project, partially facing the edges of the belt 4.

Each of the rollers 2 mentioned so far, that is, rollers 2a, 2b and 2c and guide rollers 5, consists basically of a cylindrical element 6 or sleeve freely rotating around its longitudinal axis X thanks to a corresponding pair of bearings 17 placed between the sleeve 6 and a central support shaft 7. The latter projects from the relevant ends of the sleeve 6 and is associated with respective support walls 8 which are part of a frame 18 bearing the conveyor.

As better shown in figure 2, each guide roller 5 has a pair of flanges 9, that are deployed coaxially on the corresponding outer surface of the sleeve 6; these flanges 9 are able to slide axially and rotate along and around the sleeve independently of each other.

Moreover, flexibly yielding means 10 operate on each flange (9), to maintain the flanges facing each other and reciprocally in contact in a neutral, non operating end position in which the flanges (9) cover the outer surface of the sleeve (6).

By virtue of these flexibly yielding means 10, the flanges 9 can also move away from each other axially along a direction F parallel to the longitudinal axis X of roller 5 and in opposite directions at the point of contact with the belt 4 (that is, if the belt 4 tends to move sideways) and with the possibility of rotating independently: this possibility of moving away with the flanges 9 rotating enables the flanges 9 - sleeve 6 assembly gradually to rotate according to the surface area of the belt 4 in contact with guide roller 5.

To examine construction in greater detail (see figure 2), every flange 9 consists of a first discoid section 11 at an end and in contact with the belt 4 and of a cylindrical section 12 coupling with the outer surface of the sleeve 6: this cylindrical section 12 partially houses the corresponding flexibly yielding means 10.

As an example of this solution, these flexibly yielding means 10 consist of a spring 13 for every flange 9, coaxially fitted on the respective sleeve 6 and secured at its ends in an internal circumferential seat 14 within the flange 9 and, respectively, inside a corresponding cup element 15 associated with the end of the sleeve 6.

This cup element 15 partially encloses the corresponding second section with the flange 9, to form a kind of cover, the said flange being able to slide axially inside the cup element 15 and to thus cover, jointly with the flange 9, at least half of the sleeve 6, at the neutral, non operating position of the flange.

Moreover, the cup element 15 is secured, but still able to rotate, to the sleeve 6, by a stop ring 16 linked to the corresponding end of the sleeve 6.

In practice, the guide roller 5 thus structured makes it possible to oppose the sideways wandering action of the belt 4 (shown by a hatched line in figure 1 and indicated with arrow F1) by means of initial contact of the edge of the belt 4 with the discoid section 11 of the flanges 9, which tend to impede the transverse motion of the belt 4, by beginning to rotate around the sleeve 6.

If the sideward thrust exerted by the edge of the belt 4 continues, the discoid sections 11 can slide along the sleeve 6 independently and according to the thrust direction of the belt 4. At this point, the sleeve 6 is exposed and can thus come gradually into contact with the belt 4 and likewise begin to rotate around its X axis.

When equilibrium is restored on the belt 4 and, consequently, the belt is re-positioned correctly on the three-roller groups 2a, 2b and 2c, the flanges 9 return to the neutral non operating position with the aid of spring 13.

To confirm the validity of the solution hitherto described, figure 3 illustrates a detail of a flat conveyor belt 50 showing a guide roller 5 similar to the one described, with its axis perpendicular to the axis of roller 52.

Roller 5 is located at the end of the belt 4 to enable it to intercept the end if the belt moves transversally (shown by F2) and to restore a conveying situation as described further above.

A guide roller thus constructed achieves the intended purposes by having a structure that is extremely simple, functional and, as a whole, economical.

Use of mobile flanges makes it possible to compensate the differing peripheral speeds when the belt is in contact simultaneously with both the sleeve and one of the flanges, thus reducing the risk of rapid wear of the roller and possible failure of the same.

In addition to this, the flanges enable the sleeve to start rotating gradually, thus reducing, in this case too, wear due to friction in the event of significant differences between the speeds of sleeve and belt if direct contact occurs.

Whenever use of the guide roller is necessary, the special architecture of the flanges and the possibility of sliding along the sleeve makes it possible to clean and protect the sleeve against atmospheric agents, which may be particularly aggressive if the systems are located in ports, quarries, chemical plants, etc., and/or depending on the type of material loaded on the conveyor.

The invention described can be subject to modifications and variations without thereby departing from the scope of the inventive concept.

Claims (7)

1. Claims 1) A guide roller for conveyor belts comprising a belt, initially flat, closed in a loop and tensioned by at least one pair of drums thus forming two branches, an active conveying branch and a passive return branch; one or more pairs of guide rollers being located on each side of the belt to control sideways wandering of the belt, the rollers being associated with relevant walls which support the belt on both sides, so that they project, partially facing the edges of the belt; each of the guide rollers consisting of a cylindrical element, or sleeve, rotating freely around its longitudinal axis and has a central support shaft, projecting from the ends of the sleeve, and associated with the respective support walls, characterized in that each of the guide rollers is equipped with a pair of flanges, deployed coaxially on the corresponding outer surface of the sleeve, sliding axially and able to rotate along/around the sleeve independently of each other; flexibly yielding means operate on each of the flanges to maintain the flanges facing each other and in reciprocal contact in a neutral, non operating end position in which the flanges cover the outer surface of the sleeve, the flanges being able to move away from each other axially along a direction parallel to the longitudinal axis of the other roller and in opposite directions at the point of contact with the belt and being able to rotate independently, to enable the flange - sleeve assembly gradually to rotate according to the surface area of the belt in contact with the guide roller.
2. 2) The guide roller according to claim 1, characterized in that each of the flanges consists of a first discoid end section in contact with the belt and of a cylindrical section for coupling with the outer surface of the sleeve.
3. 3) The guide roller according to claim 1, characterized in that each of the flanges consists of a first discoid end section in contact with the belt and of a cylindrical section for coupling with the outer surface of the sleeve which partially houses the corresponding flexibly yielding means.
4. 4) The guide roller according to claim 3, characterized in that the flexibly yielding means consist of a spring for each of the flanges, fitted coaxially on the respective sleeve and secured at its ends within a seat made in the internal circumference of the flange and respectively inside a corresponding cup element associated with the end of the sleeve.
5. 5) The guide roller according to claim 4, characterized in that each cup element partially encloses the corresponding flange, to form a kind of cover, the flange being able to slide axially inside the cup element and thus form, jointly with the flange, a body completely covering the sleeve, at the neutral, non operating position of the flange.
6. 6) The guide roller according to claim 4, characterized in that the cup element is secured to the sleeve, but able to rotate, by a stop ring linked to the end of the sleeve.
7. 7) The roller as in the foregoing claims and substantially as described with reference to the accompanying drawings