GB2110623A - Improvements relating to conveyors - Google Patents

Abstract

Conveyor belts are guided over sets of rollers (transomes) which form the belt into a trough, and the attitude of the rollers can be arranged to generate a self-centering action on the belt. In order to have this for a reversible conveyor (24), the rollers (21, 22, 23) are mounted on a frame (25, 26, 27) which can freely pivot within limits set by stops (30) about an axis transverse to and below the conveyor. This automatically takes up position where the outer rollers (22, 23) have their axes directed upwardly, outwardly and downstream of the conveyor motion. <IMAGE>

Description

SPECIFICATION Improvements relating to conveyors This invention relates to conveyors and is concerned with the endless belt type where the top or working run is guided and supported by arrays of transverse rollers in generally 'U' or 'V' configuration, forming that top run into a trough.

In a standard example, as shown in Figure 1 of the accompanying drawing, there are three rollers 1, 2 and 3 providing a transome. Their axes lie in a plane normal to the direction of movement of a belt 4, and this direction may be left to right or right to left as seen in the Figure. The intersecting axes form a shallow 'U', and so the belt dips along its central portion and forms a trough. Should the belt track to one side or the other, the rollers exert no influence to restore it to a central position, and in the extreme case the belt can become unseated, or at least move so far to one side that the load is split.

One solution to this problem is shown in Figure 2, where there are again three rollers 11, 12 and 13, and a belt 14. However, that moves in one direction only, from left to right as shown. The central roller 11 has its axis horizontal and normal to the direction of belt movement. The outer rollers 12 and 13 have their axes inclined from the centre line slightly downstream as well as upwardly and outwardly. When the belt is central, as shown in full lines, its edge portions engage the rollers 12 and 13 equally, and so any lateral influence they may have as a result of their slightly skew attitude is equal and opposite, and therefore mutually cancelling.However, should the belt track to one side, as indicated by the broken lines, for example to engage the roller 12 more than the roller 13, then the roller 12 will tend to urge the belt back towards its centre position. The belt has a sliding and rolling relationship with the outer rollers, and therefore there is friction. This increases the more the roller is engaged by the belt, and its resultant on the belt is downstream and towards the centre line. When there is an imbalance, the greater frictional force at one side will generate a self-centering effect.

However, if it is desired to reverse the belt of Figure 2, this effect will no longer hold, and indeed if the belt tended to track, its condition would be made worse by the attitude of the rollers.

According to the present invention there is provided a transome for a reversible conveyor comprising a generally 'U' or 'V' shaped array of rollers with their axes transverse to the conveyor direction, the outer rollers at least being mounted to incline from their inner ends upwardly, outwardly and downstream whichever the direction of motion of the conveyor.

Conveniently, the outer rollers are on a common frame freely pivoted about an axis at the same height or below the axis of a central horizontal roller. This frame may have adjustable stops so that the downstream inclination can be optimised.

For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the remaining figures of the accompanying drawing, in which: Figure 3 is a front view of a three roller transome, and Figure 4 is a side view of the transome of Figure 1.

This transome has a central roller 21 with its axis horizontal and two outer rollers 22 and 23 with their axes in the same plane but directed outwardly and upwardly to form a cradle for a belt 24. The rollers are carried by brackets 25 and 26 upstanding from a bar 27 whose ends are journalled in bearing blocks 28. These have a horizontal axis parallel to but below the axis of the roller 21. The bar 27 has arms 29 projecting in both directions of belt movement, and underneath the ends of these are adjustable stops 30 which co-operate with conveyor frame 31.

In operation, the belt 24 urges the roller assembly to pivot about the axis of the bar 27 so that the downstream stop 30 engages the frame 31. The outer rollers 22 and 23 then have their upper, outer ends slightly downstream of the centre roller 21, and consequently perform a centering action on the belt 24. Their inclination can be changed by adjusting the stop.

Should the belt be reversed, the transome will flip over automatically so that the other stop 30 engages the frame 31.

1. A transome for a reversible conveyor comprising a generally 'U' or 'V' shaped array of rollers with their axes transverse to the conveyor direction, the outer rollers at least being mounted to incline from their inner ends upwardly, outwardly and downstream whichever the direction of motion of the conveyor.

2. A transome as claimed in claim 1, wherein the outer rollers are on a common frame freely pivoted about an axis at the same height as, or below, the axis of a central horizontal roller.

3. A transome as claimed in claim 2, wherein the frame has ajustable stop means to set a desired downstream inclination.

4. A transome for a reversible conveyor substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements relating to conveyors This invention relates to conveyors and is concerned with the endless belt type where the top or working run is guided and supported by arrays of transverse rollers in generally 'U' or 'V' configuration, forming that top run into a trough. In a standard example, as shown in Figure 1 of the accompanying drawing, there are three rollers 1, 2 and 3 providing a transome. Their axes lie in a plane normal to the direction of movement of a belt 4, and this direction may be left to right or right to left as seen in the Figure. The intersecting axes form a shallow 'U', and so the belt dips along its central portion and forms a trough. Should the belt track to one side or the other, the rollers exert no influence to restore it to a central position, and in the extreme case the belt can become unseated, or at least move so far to one side that the load is split. One solution to this problem is shown in Figure 2, where there are again three rollers 11, 12 and 13, and a belt 14. However, that moves in one direction only, from left to right as shown. The central roller 11 has its axis horizontal and normal to the direction of belt movement. The outer rollers 12 and 13 have their axes inclined from the centre line slightly downstream as well as upwardly and outwardly. When the belt is central, as shown in full lines, its edge portions engage the rollers 12 and 13 equally, and so any lateral influence they may have as a result of their slightly skew attitude is equal and opposite, and therefore mutually cancelling.However, should the belt track to one side, as indicated by the broken lines, for example to engage the roller 12 more than the roller 13, then the roller 12 will tend to urge the belt back towards its centre position. The belt has a sliding and rolling relationship with the outer rollers, and therefore there is friction. This increases the more the roller is engaged by the belt, and its resultant on the belt is downstream and towards the centre line. When there is an imbalance, the greater frictional force at one side will generate a self-centering effect. However, if it is desired to reverse the belt of Figure 2, this effect will no longer hold, and indeed if the belt tended to track, its condition would be made worse by the attitude of the rollers. According to the present invention there is provided a transome for a reversible conveyor comprising a generally 'U' or 'V' shaped array of rollers with their axes transverse to the conveyor direction, the outer rollers at least being mounted to incline from their inner ends upwardly, outwardly and downstream whichever the direction of motion of the conveyor. Conveniently, the outer rollers are on a common frame freely pivoted about an axis at the same height or below the axis of a central horizontal roller. This frame may have adjustable stops so that the downstream inclination can be optimised. For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the remaining figures of the accompanying drawing, in which: Figure 3 is a front view of a three roller transome, and Figure 4 is a side view of the transome of Figure 1. This transome has a central roller 21 with its axis horizontal and two outer rollers 22 and 23 with their axes in the same plane but directed outwardly and upwardly to form a cradle for a belt 24. The rollers are carried by brackets 25 and 26 upstanding from a bar 27 whose ends are journalled in bearing blocks 28. These have a horizontal axis parallel to but below the axis of the roller 21. The bar 27 has arms 29 projecting in both directions of belt movement, and underneath the ends of these are adjustable stops 30 which co-operate with conveyor frame 31. In operation, the belt 24 urges the roller assembly to pivot about the axis of the bar 27 so that the downstream stop 30 engages the frame 31. The outer rollers 22 and 23 then have their upper, outer ends slightly downstream of the centre roller 21, and consequently perform a centering action on the belt 24. Their inclination can be changed by adjusting the stop. Should the belt be reversed, the transome will flip over automatically so that the other stop 30 engages the frame 31. CLAIMS

1. A transome for a reversible conveyor comprising a generally 'U' or 'V' shaped array of rollers with their axes transverse to the conveyor direction, the outer rollers at least being mounted to incline from their inner ends upwardly, outwardly and downstream whichever the direction of motion of the conveyor.

2. A transome as claimed in claim 1, wherein the outer rollers are on a common frame freely pivoted about an axis at the same height as, or below, the axis of a central horizontal roller.

3. A transome as claimed in claim 2, wherein the frame has ajustable stop means to set a desired downstream inclination.

4. A transome for a reversible conveyor substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawing.