GB2143492A

GB2143492A - Conveyor belt tensioner

Info

Publication number: GB2143492A
Application number: GB08417014A
Authority: GB
Inventors: John George Darley
Original assignee: Conveyor Improvements Doncaster Ltd
Current assignee: Conveyor Improvements Doncaster Ltd
Priority date: 1983-07-18
Filing date: 1984-07-04
Publication date: 1985-02-13
Also published as: GB8417014D0

Abstract

So that the operation of tensioning a conveyor belt can be carried out within sight of the driving drum, the apparatus for tensioning comprises a pair of freely rotatable rollers disposed side by side on one side of the belt and a single roller located equidistant the said pair of rollers on the other side of the belt, and means whereby the roller or rollers on one side of the belt can be forced towards the roller or rollers on the other side of the belt. <IMAGE>

Description

SPECIFICATION Conveyor belt tensioner The invention relates to apparatus for tensioning an endless conveyor belt, for example a conveyor belt such as might be used in a coal mine for the conveying of coal.

When a new or newly repaired conveyor belt has been fitted to extend around the usual driving and idler drums at the opposite ends of a conveyor run, the upper length of belt resting at intervals on the usual support rollers, it is still a considerable operation to tighten the belt sufficiently to ensure a belt tension around the driving drum to bring about non-slip frictional engagement with said drum. A so-called snub drum may be fitted adjacent the driving drum to increase the effective arc of contact of the belt around said drum, but this takes only a little of the slack out of the belt and other means must be employed to tension the belt sufficiently.Such other means generally involve the adjustment of the idler drum away from the driving drum, but of course the idler drum is remote from the driving drum and it is difficult to know when sufficient tension has been produced in the belt. The invention has for its object to provide very simple apparatus whereby an endless conveyor belt can be tensioned very easily and conveniently.

According to the invention, there is provided apparatus for tightening an endless conveyor belt, the apparatus including a frame arrangement having pairs of parallel posts at opposite sides of the conveyor between which extend respective mounting members for bearing housings for a pair of freely rotatable rollers disposed side by side on one side of the belt and for a single roller located equidistant the said pair of rollers on the other side of the belt, the arrangement being such that the roller or rollers on one side of the belt can be forced towards the roller or rollers on the other side of the belt sufficiently to cause the belt to be deflected so that slackness is taken out of the belt and a required tension is produced in the belt.Means which are provided whereby the roller or rollers on the one side of the belt can be forced towards the roller or rollers on the other side of the belt may include bolts which abut against adjustable mounting members on the opposite sides of the conveyor. In this case, the bolts may extend through brackets which are secured to the pairs of posts at the opposite sides of the conveyor and which overlie end portions of said adjustable mounting members. The bolts will preferably be fitted with nuts which can be used as locknuts to fix the bolts in adjusted positions. The adjustable mounting members will preferably be capable of being fixed in their adjusted positions between the respective pairs of parallel posts by bolts which extend through slots in said posts.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a perspective view of apparatus embodying the invention, in use for tensioning a conveyor belt, Figure 2 is an exploded view of the apparatus, and Figure 3 is a semi-diagrammatic view which will be referred to.

Referring now to Figure 1 of the drawings, the apparatus 10 there illustrated is shown to be installed close to a driving drum 1 2 around which an endless conveyor belt 14 extends. A so-called snub drum 1 6 is shown to have been fitted adjacent the driving drum, this being shown to increase the effective arc of contact of the belt around the drum.

The apparatus 10 includes a frame structure including, at the opposite sides of the conveyor, pairs of upstanding posts 18 between which extend fixed mounting members 20 and adjustable mounting members 22.

Respective sets of three bearing housings 24, 26 and 28 are located in the spaces between the fixed mounting members and the adjustable mounting members. The bearing housings 24 and 26 of each set are bolted as shown in spaced relation on the fixed mounting members. The bearing housing 28 of each set is bolted beneath the respective adjustable mounting member and is located equidistant the bearing housings 24 and 26. Respective rollers 30, 32 and 34 are mounted for free rotation in bearings (not shown) in the oppositely disposed bearing housings.

The adjustable mounting members 22 are bolted in position between the respective posts of the frame structure by bolts 36 which extend through elongate slots 38 in said posts. Brackets 40 which are welded to the upper ends of the posts overlie the opposite end portions of the adjustable mounting members and carry bolts 42 which extend downwards to abut against said mounting members. The bolts are fitted with nuts 44 which can be used as locknuts to fix the bolts in adjusted positions.

The arrangement is such that when a return run of the endless conveyor belt concerned has been passed through the initially widely spaced rollers of the apparatus 10, that is to say to extend over the rollers 30 and 32 and beneath the roller 34, the adjustable mounting members 22 can be forced downwardly by the bolts 42 so that the roller 34 is brought to a position in which it causes the belt to be deflected, as shown in Figure 3, as it passes through the apparatus. This has the effect of taking the slackness out of the conveyor belt and can be continued until there is sufficient tension in the belt to bring about non-slip frictional engagement with the driving drum.The fact that the tensioning apparatus is located adjacent the driving drum makes it very easy for a person tensioning the belt to observe that he has brought about sufficient tension in the belt and to avoid over-tensioning the belt. Over-tensioning of a conveyor belt can overload the bearings of the driving and idler drums and can ncedlessly overstress the belt itself and lead to premature failure of the belt. When the belt has been tensioned sufficiently, the bolts 42 can be fixed in position by the nuts 44, and the adjustable mounting members 22 can be fixed in their adjusted positions between the respective posts 1 8 by tightening the bolts 36.

Thus there is provided very simple apparatus whereby an endless conveyor belt can be tensioned very easily and conveniently. An added advantage of using apparatus embodying the invention is that since the three rollers are all of very much smaller diameter than the driving and idler drums, and in fact smaller than the usual snub drums if fitted, there is a considerable centrifugal effect tending to throw off any water adhering to the belt.

Consequently, the belt will tend to be drier when such tensioning apparatus is used, this again tending to promote non-slip engagement of the belt around the driving drum.

Various modifications may be made. For example, it will be understood that the bearing housings 28 for the single roller could be bolted on the fixed mounting members of the frame structure and the bearing housings 24 and 26 for the pair of side by side rollers could be bolted in spaced relation beneath the adjustable mounting members.

Claims

1. Apparatus for tightening an endless conveyor belt, the apparatus including a frame arrangement having pairs of parallel posts at opposite sides of the conveyor between which extend respective mounting members for bearing housings for a pair of freely rotatable rollers disposed side by side on one side of the belt and for a single roller located equidistant the said pair of rollers on the other side of the belt, the arrangement being such that the roller or rollers on one side of the belt can be forced towards the roller or rollers on the other side of the belt sufficiently to cause the belt to be deflected so that slackness is taken out of the belt and a required tension is produced in the belt.

2. Apparatus according to claim 1, in which means which are provided whereby the roller or rollers on the one side of the belt can be forced towards the roller or rollers on the other side of the belt include bolts which abut against adjustable mounting members on the opposite sides of the conveyor.

3. Apparatus according to claim 2, in which the bolts extend through brackets which are secured to the pairs of posts at the opposite sides of the conveyor and which overlie end portions of said adjustable mounting members.

4. Apparatus according to either one of claims 2 and 3, in which the bolts are fitted with nuts which can be used as locknuts to fix the bolts in adjusted positions.

5. Apparatus according to any one of claims 2 to 4, in which the adjustable mounting members are capable of being fixed in their adjusted positions between the respective pairs of parallel posts by bolts which extend through slots in said posts.

6. Apparatus for tightening an endless conveyor belt, the apparatus being constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.