GB2087337A - Side seal clamping means for belt conveyors - Google Patents

Abstract

Flexible seal elements or "skirt rubbers" (7) provide a seal between a moving conveyor belt (1) and a stationary sidewall (5). In use, the bottom of these skirt rubbers (7) become worn which necessitates periodic lowering of the rubbers (7) to maintain their sealing contact with the conveyor belt (1). To facilitate such adjustment of the skirt rubbers (7), a clamping arrangement is provided for holding the skirt rubbers (7) in position, this arrangement comprising a pivoted clamping bar (8) for clamping a skirt rubber (7) against the outside of the side wall (5), and tightenable means (14) for pressing the clamping bar (8) towards the sidewall (5). Due to this arrangement, the whole length of skirt rubber (7) associated with the clamping bar (8) can be readily lowered simply by slackening of the said tightenable means (14). The tightenable means may comprise a threaded element (14) which is engaged in a threaded aperture formed in a plate (16) rigid with the sidewall (5) and which can be tightened down onto the clamping bar (8). <IMAGE>

Description

SPECIFICATION Belt conveyors The present invention relates to belt conveyors of the type in which a flexible seal element is used to provide a seal between a moving conveyor belt and a stationary sidewall.

Belt conveyors of the aforesaid type are used, for example, to transport coal and similar quarried materials and generally comprise a belt conveyor laterally bounded by sidewall plates. These sidewall or "skirt" plates are of substantially rigid form and are supported above the belt edge portions by supports arranged at intervals along the conveyor. In order to ensure an efficient sealing between the skirt plates and the conveyor belt, each skirt plate has an associated flexible seal element, known as a skirt rubber, which projects below the bottom of the plate into sealing engagement with the belt. Due to this sealing arrangement, material carried on the conveyor belt is prevented from escaping between the belt and skirt plates.

In known belt conveyors of the aforesaid type, the skirt rubbers are carried by their associated skirt plates with each skirt plate and associated skirt rubber being arranged in overlapping arrangement and being compressed together by bolts to form a sealed connection therebetween.

After a period of time the skirt rubbers become worn due to their sliding contact with the moving conveyor belt. In order to maintain the efficiency of the seal between the skirt plates and the conveyor belt, the skirt rubbers have periodically to be lowered relative to their associated skirt plates so that they once again sealingly seat on the belt. The required adjustment in position of the skirt rubbers is provided for by forming the bolt holes in skirt rubbers as vertical slots.

Since the bolts holding the skirt rubbers to the skirt plates must be closely spaced to ensure proper sealing therebetween, the operation of adjusting the level of the skirt rubbers is extremely time consuming as all the bolts must be loosened and then subsequently retightened. Furthermore, the replacement of a skirt rubber for any reason is also a very long process since in ths case the bolts must all be completely undone.

It is an object of the present invention to provide an arrangement for securing the skirt rubbers in position which facilitates their adjustment and replacement.

According to one aspect of the present invention, there is provided a belt conveyor of the aforesaid type, in which the said flexible seal element is secured in position by clamping arrangement comprising an elongate clamping bar which extends along the outside of the sidewall and is pivotally mounted on structure rigid therewith for pivotal movement towards and away from the sidewall about an axis parallel to and offset from itself, and tightenable means for pressing the clamping bar towards the sidewall whereby to enable the seal element to be clamped therebetween.

Due to this arrangement, the clamping in position of a substantial length of seal element can be effected rapidly enabling the time required to adjust the level of the seal element to be shortened.

The clamping arrangement of the invention can be used both on flat conveyors and on trough conveyors in which the peripheral portions of the conveyor belt are slanted upwards.

Preferably, the said tightenable means comprises a threaded element which engages in a threaded aperture in a fixed member and which can be tightened down either on the clamping bar itself or on a structure rigid therewith. Advantageously, the clamping bar is of angle-iron or flat bar form and is backed by a supporting structure designed to give added rigidity and prevent flexing of the bar under the clamping pressure.

Preferably the said tightenable means is displaceable from its normal position in which it can be tightened up to effect clamping of the seal element, into a position in which the clamping bar can be swung back from the sidewall, uninhibited by the tightening means.

With the clamping bar swung away from the sidewall, it becomes a relatively simple matter to remove and replace the seal element.

Advantageously, the tightenable means is held in its normal position by retaining means which can be quickly released. One very simple form of retaining means comprises freely engageable male and female members, one member being mounted rigid with the sidewall and the other being carried by the said tightenable means; normally, the male member will be engaged with the female member to locate the tightenable means in position, the reaction force experienced by the tightenable means when tightened up, serving to frictionally secure the male and female members together.

Preferably, the conveyor is provided with a longitudinally-extending wire-mesh guard protecting the side of the conveyor, the tightenable means being disposed outside the guard and the seal element being externally accessible by means of a tool passed through slots provided in the guard whereby to enable adjustment of said seal element without removal of the guard.

A conveyor skirt-seal clamping arrangement embodying the invention will now be particularly described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a side elevation of a belt conveyor provided with a skirt-seal held in positon by clamping bar of the clamping arrange ment to be described, the conveyor belt and idlers being ommitted for clarity and only one end mounting of the clamping bar being shown; Figure 2 is a transverse half-section through the belt conveyor taken on line ll-ll of Fig. 1; Figure 3 is a section, to reduce scale, taken on line Ill-Ill of Fig. 1 and illustrating the position of a safety guard, the opposite clamping-bar end mounting to that shown in Fig. 1 being visible; and Figure 4 is a section, to a reduced scale, taken on line IV-IV of Fig. 1 but showing a modified form of clamping bar and clampingbar support structure.

As can be seen in Fig. 2, the belt conveyor in relation to which one embodiment of the present invention is to be described, comprises a conveyor belt 1 running on horizontal idlers 2. The lateral portions 3 of the belt 1 slope upwardly so that the belt as a whole is shaped like a trough; the angle between the lateral portions 3 and the horizontal will generally be between 20 and 53 . The belt lateral portions 3 run on troughing idlers 4.

The central conveying zone of the belt 1 is laterally bounded on both sides by stationary sidewalls constituted by skirt plates 5. Each skirt plate 5 is positioned above the corresponding belt lateral portion 3 and is supported at intervals along the conveyor by fixed supports 6 integral with the idler mounting structure (not shown). The skirt plates 5 are of substantially rigid form.

To prevent material carried by the conveyor from escaping between the belt and the bottom of the skirt plate 5, a flexible skirt seal or rubber 7 is clamped to the outside of the skirt plate 5. This skirt rubber 7 extends along the whole length of the skirt plate and projects down below the bottom of the plate 5 into sealing engagement with the belt 1.

The arrangement for clamping the skirt rubber 7 in position against the skirt plate 5 is shown in Figs. 1 to 3 and includes a respective clamping bar 8 extending parallel to the skirt rubber 7 between adjacent supports 6.

Each clamping bar is pivotally mounted by means of two end mountings 50 one of which is visible in Figs. 1 and 2 and the other of which is visible in Fig. 3. Each end mounting 50 includes a triangular support plate rigidly connected to the corresponding end of the clamping bar 8. Each plate 9 is formed with a key siot opening 51 which enables the plate to be readily and positively engaged over a fixed pintle 10 for pivotal movement relative to the skirt plates 5, the fixed pintle 10 being carried by a support bracket 11 which is rigid with the skirt plate 5 and projects laterally therefrom. The pintles 10 carrying the two triangular support plates 9 associated with each clamping bar 8 define an axis of pivoting for the clamping bar 8 which is parallel to and offset from the bar itself; as a result, the bar 8 can be swung back away from the skirt rubber 7.

Each clamping bar 8 has a right-angle cross-sectional form and is arranged to contact the skirt rubber 7 with its two free end edges 1 2. Each clamping bar 8 is backed by a tubular support structure comprising a main support bar 52 extending between, and welded to, the two triangular support plates 9 associated with the clamping bar 8, and a plurality of connecting elements 53 interconnecting the main support bar 52 with the clamping bar 8. This tubular support structure 52, 53 increases the rigidity of the clamping bar 8 and, in addition, the support bar 52 serves as a handle by means of which the bar 8 can be swung back from the skirt rubber 7.

Associated with each support bracket 11 is a clamping screw assembly comprising a clamping screw 14 engaged in a threaded aperture 1 5 provided in a mounting plate 1 6.

A bridge piece 25 is welded to the top of the bracket 11 to define therewith a pocket 26 into which the mounting plate 1 6 can be freely slid (in direction from right to left as viewed in Fig. 1). The upper end of the clamping screw 14 is provided with a turning bar 1 8 which facilitates rotation of the screw 14. The lower end of the screw 14 abuts against a block 1 9 rigid with the triangular plate 9 which is pivoted on the bracket 11 associated with the screw 1 4.

By using their turning bars 18, the two clamping screws 14 associated with each clamping bar 8 can be tightened down on their corresponding blocks 1 9 which result in the clamping bar 8 being pressed against the skirt rubber 7. As a consequence, the skirt rubber is clamped between the outside of the skirt plate 5 and the clamping bar 8. Furthermore, upon the clamping screws 14 being tightened up, the reaction forces experienced thereby serve to frictionally jam the associated mounting plates 1 6 within their corresponding pockets 26. As soon as each screw 14 is slackened off, the clamping-screw mounting plate 1 6 can be with-:' awn from its pocket 26 with ease.

Due to the above-described clamping arrangement, the repositioning of the skirt rubber 7 to compensate for wear can be speedily effected. Thus, to carry out this repositioning, the clamping screws 14 are first rotated to controllably relieve the clamping pressure exerted- by the clamping bars 8 on the skirt rubber 7; this initial loosening is carried out such that there remains a residual clamping pressure holding up the skirt rubber 7.The skirt rubber 7 can then be pushed down into position in a controlled manner against the resistance of the frictional forces experienced by the skirt rubber due to the residual clamping pressure; advantageously the skirt rubber 7 is forced down using a lever 54 (shown dashed in Fig. 3) inserted under the main support bar 52, the latter serving as a fulcrum whereby upwards movement of the outer end of the lever produces a downwards force on the skirt rubber. Once the skirt rubber 7 has beensRositioned as desired, the clamping screws 14 are retightened.

When it becomes necessary to replace the skirt rubber 7 for any reason, the clamping screws 14 are loosened to enable the clamping screw assemblies to be disengaged from the pockets 26 and removed so that the clamping bars 8 and their associated support structure can be either swung back and away from the skirt rubber 7 or, more conveniently, lifted off the pintles 10 and taken away altogether while the skirt rubber is replaced.

As shown in Fig. 3, the conveyor can be provided with longitudinally-extending wiremesh side guards 55 which project outwardly from the conveyor skirt plates 5 and then down over the clamping bar support structure 52, 53, the extreme lateral portions of the moving belt 3, and the outer ends of the rotating troughing idlers 4, thereby preventing accidental contact with the otherwise exposed moving components of the conveyor. Each guard 55 is arranged to be carried by the corresponding support bar 52 in such a manner as to enable the guard 55 to be readily lifted away to provide access to the conveyor.

Each guard 55 is also supported along its lower edge by frame members (not shown) fixed to the supports 6.

In order to enable the adjustment of the skirt rubber 7 without removal of the guards 55, the latter are so configured that the clamping screws 14 of the skirt-rubber clamping arrangement are located outside the guards 55 and, in addition, the guards are provided with longitudinal slots 56 to permit the insertion of the lever 54 as indicated in Fig. 3.

Shown in Fig. 4 is a modified form of the skirt-rubber clamping arrangement in which the clamping bar 8, instead of being constituted by a length of angle iron, is formed by a flat metal strip capable of conforming to uneveness in the skirt rubber 7 caused by uneveness in the skirt plate 5. This conformability is achieved by arranging for the connecting elements 53 which join the flat-strip clamping bar 8 to the main support bar 52, to be adjustable in length. To this end, each connecting element 53 comprises an internallythreaded first tube element 60 welded to the bar 52, a second tube element 61 welded to the clamping bar 8 coaxial with the tube element 60, and an adjustment element 62 interposed between the tube elements 60, 61.The adjustment element 62 includes a threaded portion 63 engaging within the tube element 60, a nut portion 64 by means of which the element 62 can be rotated, and a locating portion 65 seating within the tube element 61. Adjustment of the spacing of the clamping bar 8 from the support bar 52 is effected by rotation of the element 62.

Various other modifications to the abovedescribed clamping arrangement are, of course, possible. Thus for example, the clamping bar 8 could be pivotally mounted on its triangular support plates 9 and connecting elements 53 to ensure that the pressure exerted by the bar 8 against the skirt rubber 7 is evenly distributed across the width of the clamping bar 8.

Furthermore, the plates 9 could be pivoted on the support brackets 11 by nut and bolt combinations instead of by the keyhole slot and pintle arrangement shown. A nut and bolt could also be used to releasably secure the mounting plate 1 6 of each clamping screw assembly to the associated suport bracket 11 in place of the bridge piece 25.

Another alternative to using the bridge piece 25 to secure each mounting plate 1 6 in position, would be to use a quick-release clamping arrangement comprising a cam element pivotally mounted on an arm rigid with the bracket 11 and rotatable by means of a handle. By arranging for the cam element to progressively clamp the mounting plate 1 6 in position against the bracket 11 as the handle is operated, a quick and simple clamping of the mounting plate is achieved.

Claims (11)

1. A belt conveyor of the type in which a flexible seal element is used to provide a seal between a conveyor belt and a stationary sidewall, wherein the said flexible seal element is secured in position by a clamping arrangement comprising an elongate clamping bar which extends along the outside of the sidewall and is pivotally mounted on structure rigid therewith for pivotal movement towards and away from the sidewall about an axis parallel to, and offset from, itself, and tightenable means for pressing the clamping bar towards the sidewall whereby to enable the seal element to be clamped therebetween.

2. A belt conveyor according to Claim 1, wherein the said tightenable means comprisees a threaded element engaged in a threaded aperture provided in a member fixed relative to the sidewall, the arrangement of the threaded element being such that it can be tightened down, by rotation, either on the clamping bar itself or on a structure rigid therewith.

3. A belt conveyor according to Claim 1 or Claim 2, wherein the said tightenable means can be moved from its normal position in which it can be tightened up to effect clamping of the seal element, into a position in which the clamping bar can be swung back from the sidewall, uninhibited by the tightenable means.

4. A belt conveyor according to Claim 3, wherein the tightenable means is held in its normal position by retaining means which can be quickly released to enable complete removal of the tightenable means.

5. A belt conveyor according to Claim 4, wherein said retaining means comprise freely engageable male and female members, one member being fixed relative to the sidewall and the other being carried by the said tightenable means, said male and female members when engaged serving to locate the tightenable means in its normal position with the reaction force experienced by the tightenable means when tightened up, serving to frictionally secure the male and female members together.

6. A belt conveyor according to any one of the preceding claims, wherein the clamping bar is backed by a rigid supporting structure arranged to increase the rigidity of the bar and reduce flexing of the bar under the clamping pressure.

7. A belt conveyor according to Claim 6, wherein the supporting structure of the clamping bar includes a main support bar extending parallel to the clamping bar and spaced laterally therefrom on the side of the clamping bar away from the sidewall, the main supporting bar being joined to the clamping bar by connecting elements.

8. A belt conveyor according to Claim 7, wherein the clamping bar is of strip form, the clamping bar being joined to the main support bar by connecting elements which are adjustable in length whereby to enable the clamping bar to be set to conform to any uneveness in the sidewall.

9. A belt conveyor according to any one of the preceding claims, wherein the conveyor is provided with a longitudinally-extending wire-mesh guard prntecting the side of the conveyor, the tightenable means being disposed outside the guard and the seal element being externally accesible by means of a tool passed through slots provided in the guard whereby to enable adjustment of said seal element without removal of the guard.

10. A belt conveyor according to Claim 9, when dependent on Claim 7 or Claim 8, wherein the guard is arranged to seat on said main support bar and the latter is so positioned as to enable a tool to be passed under the support bar and engaged with the top of the seal element whereby to enable the seal element to be levered downwards with the support bar acting as a fulcrum for the tool.

11. A skirt rubber clamping arrangement for a belt conveyor, said clamping arrangement being substantially as hereinbefore described with reference to Figs. 1 and 2, of the accompanying drawings.