GB2187428A - Bucket conveyor device for clearing stockpiles of bulk materials - Google Patents

Abstract

A device for clearing stockpiles of bulk materials has an endless conveyor with carrier buckets (7) each of which has at least one ploughshare-like guide face (12) equipped with a cutting edge (13) which penetrates and cuts away the material of the stock pile. The guide face is arranged at the leading edge of the floor (10) of the carrier bucket (7), and directs material removed from the stockpile onto the floor of the preceding bucket. To improve the filling ratio of the carrier buckets (7) whilst at the same time simplifying the construction of the carrier buckets, the inner edge of each guide face (12) defines an opening (15) in the carrier bucket of which that guide face forms part, enabling material removed by the guide face to pass onto the floor (10) of that bucket in addition to being directed onto the floor of the preceding bucket. <IMAGE>

Description

SPECIFICATION Device for clearing stockpiles of bulk materials The invention relates to a device for clearing stockpiles of bulk materials.

A known arrangement for clearing a stockpile comprisesabridgewhich can be moved inthedirection ofthe stockpile and which spans the base ofthe stockpile. The bridge carries an endless conveyor arrangement incorporating carrier buckets each of which has at least one ploughshare-like guide face equipped with a cutting edge which penetrates the material of the stockpile. The material cut away from the stockpile by the guideface of one carrier bucket is directed onto the floor ofthe preceding carrier bucket (in the conveying direction) and the floors of the carrier buckets together form a closed supporting surfaceforthe bulk material. At the end ofthe run of the conveyor, where the latter passes over a tail pulley, the bulk material falls out of the carrier buckets and can be removed.

This known construction does have the advantage that, because the carrier bucket floors form a closed supporting surfaceforthe bulk material, it can be used in particuiarfor bulk materials susceptibleto abrasion, such as coal and fertilizers. However, because the material cut away by a guide face is guided only onto the floor of the preceding bucket, the amount of material entering the buckets is limited and they are filled onlyto a minimum level.

The problem with which the present invention is concernedisthatofimprovingthefilling ratioofthe carrier buckets whilst, if possible, making use of carrier buckets of comparatively simpie construction.

The present invention provides a deviceforclearing a stockpile of bulk material, comprising an endless conveyor having a plurality of carrier buckets each of which has at least one guide face with a cutting edge arranged, in use, to penetrate the material of the stockpile, there being an opening in the bucket through which material removed from the stockpile by the guide face can pass into the bucket.

The guide face may be arranged to direct material removed from the stockpile into the preceding carrier bucket. The floors of the carrier buckets advantageouslyform a continuous supporting surface for material removed from the stockpile.

In embodiments ofthe invention described herein, the guide face is arranged at the front of the bucket and the lower edge of the guideface extends obliquely-forwards in the conveying direction. The floor ofthe bucket extends across the entire width, and as far as the tip, of the guide face. Intheseembodi- ments, the inner edge of the guide face defines the opening in the bucket.

Aforwardly-directed deflector face may be formed atthe top edge ofthe guideface. The or each deflectorface of a bucket may be joined to a supporting structure by means of which the carrier bucket is linked to a conveyor chain.

In one form of the invention, suitable for clearing a longitudinal stockpile, the carrier buckets are constructed symmetrically with respect to the long itudinal axis. More particularly, each bucket may have two guide faces, the inner edges of which define the sides ofthe opening and which are arranged symmetrically with respect to the longitudinal axis.

In anotherform of the invention, suitableforclear- ing a circular stockpile, the carrier buckets are con structedwith oneguideface and with a sidewall which extends in the conveying direction and which defines the other side of the opening.

Embodiments ofthe invention are illustrated, by way of example, in the drawings, in which: Figure ? shows a diagrammatic view of a device forclearing a bulk material stockpilewhich has been banked up as a longitudinal stockpile; Figureashows a similarview of a deviceforclear- ing a circular stockpile; Figure 3 shows a diagrammatic side view of the delivery end ofthe conveyor chain used in Figures 1 and 2; Figure4shows a plan view of three carrier buckets of the conveyor chain used in the device shown in Figure 2; Figure 5shows a perspective view of a carrier bucket ofthe conveyor chain shown in Figure 1; Figure 6shows an enlarged plan view of one ofthe carrier buckets shown in Figure 4;; Figure 7shows a rearviewofthe carrier bucket shown in Figure 6, and Figure 8shows a side view of the carrier bucket shown in Figure 6.

Figures1 and2showdiagrammaticallythecon- structions of devices for clearing bulk material stock pileswhich have been banked up longitudinal stockpile and as a circular stockpile, respectively.

Each of these two devices comprises a bridge 1 which can be driven in the direction of the stockpile and which spansthe base of the stockpile. In the em bodiment of Figure 1 forclearing a longitudinal stockpile, the bridge 1 is driven at its two ends on linearly-extending rails2 running on eithersideof the longitudinal stockpile. In the case of the device illustrated in Figure 2 for clearing a circularstockpile, the bridge 1 is rotatably mounted at one end of a central column 3 which is arranged in the middle ofthe circularstockpile,whilethe other end ofthe bridge 1 is supported on a rail 4which extends in a circle around the circular stockpile.

On the underside of each bridge 1 there is arranged an endless conveyor which comprises a conveyorchain6which isguided at its endsaroundtwo tail pulleys 5, and carrier buckets 7 which are arranged on the conveyor chain and which are not shown in any detail in Figures 1 and 2. With the assistance of these carrier buckets 7 the material which has been banked up to form the bulk material stockpile is conveyed to the left in the construction shown in Figure 1 and to the right in the construction shown in Figure 2. In the first embodiment (Figure 1), the material passes onto a conveyor belt 8 by which it istransported forfurther processing.In the second embodi ment (Figure 2), the material passes into a central funnel 9 from which it is likewise carried away by an underground conveyor belt, not illustrated in the drawings, and delivered to the subsequent processing stations.

Figure 3 is a diagrammatic illustration of how, in both embodiments, the material taken up by the carrier buckets 7 is discharged from the conveyor, in the region ofthe rear tail pulley 5, for the purpose of furthertransport. The drawing shows thatthe material lies on the rearwardly projecting floors ofthe carrier buckets and that these floors form a con tinuoussupportingsurfaceforthebulkmaterial in the underneath region of the conveyor chain 6. As soon as the carrier buckets 7 have been lifted, in the course of their rotating path around the tail pulley 5, the floors tilt, sothatthe material is able to fall backwards out ofthe buckets.The material then passes eitherontotheconveyorbelt8shown in Figure 1 or into the funnel 9 shown in Figure 2.

Figure 5 illustrates a carrier bucket 7 as used on the conveyor chain 6 of the device according to Figure 1.

This carrier bucket 7 has a floor 10 which extends across the entire width ofthe conveyor and runs as farasthetips 11 of ploughshare-like guide faces 12 which are arranged on both sides of the carrier bucket 7 and each of which has a cutting edge 13 with which it cuts into the material lying at the base ofthe stockpile. With their inner edges 1 4the two guide faces 12 define an opening 15 which lies in the middle ofthe floor 10, the latter adjoining the opening atthe rear. Atthetop edge ofthe guidefaces 12 there is arranged in each case a deflectorface 16 which runs approximately parallel with the floor 10 and is directed forwards in the direction of movement ofthe carrier bucket 7.This deflectorface 16 serves as a type of break-water and deflects material sliding upwards along the guideface 12, as will be described below.

Above the floor 10 there is a supporting structure 17 which is joined to thedeflectorfaces 16 and tithe guide faces 12. The carrier bucket 7 is secured by this supporting structure 17 to the conveyor chain 6.

While the carrier bucket shown in Figure 5 and used on the device shown in Figure 1 has a ploughshare-like guide face 12 on both sides, becausethe longitudinalstockpileto be cleared lies to the right and to the left in the discharge direction of the conveyor chain 6, the carrier buckets 7 of the conveyor shown in Figure 2 (illustrated in Figures 4 and 6 to 8) have such a guide face 12 only on one side. On the other side, the floor 10 is provided with a sidewall 18 extending in the conveying direction. This side wall 18 accordingly defines the other side ofthe opening 15 and is additionallyjoined to the supporting structure 17.This asymmetric construction ofthe carrier bucket 7 is necessary because, when using the device on a circular stockpile, the part of the stockpileto be cleared always lies on the same side of the bridge 1.

In the second form of carrier bucket shown in Fig urns 4 and 6to 8 it is a Is also apparentthatthefloor 10 extends across the entire width and as far as the tip 11 ofthe guide face 12, which is provided at its upper edge with a deflector face 16. Apart from the fact that it is asymmetric,the basic construction of this bucket (including the opening 15 provided in the middle) is thesameasthatshown in Figure 5.

As the conveyor chain 6 moves, the cutting edge 13 ofthe guide face(s) 12 of each carrier bucket7 pen etrates the bulk material at the base of the stockpile and cuts this material out. The material is guided, during the course of the movement, byway ofthe backwardly sloping guide faces 12 into the inside of the carrier buckets 7, wherein material sliding upwards on a guide face 12 of any particularbucketis deflected by the forwardly-directed deflector face 16 so that it cannot slide up overthe guide face 12 but moves forwards onto that part of the floor 10 of the preceding carrier bucket 7 which arranged in front oftheguideface in question.Atthebeginning ofthe conveying movement, material sliding upwards on a guide face 12 of one of the carrier buckets 7 moves only onto the floor 10 of the preceding carrier bucket 7 but, as the charge ofthis preceding carrier bucket7 increases, a portion of the material passes through the opening 15 and onto the middle region ofthe floor 10 ofthe carrier bucket carrying the guide face in question. Because a portion of the transported material passes through the opening 15, the charge ofthe carrier buckets 7 effectively increases. The construction of the floor 10in the region of the guide faces 12 prevents material that has been taken up and carried along by the guide faces 12 from being comminuted by constantfriction with the bottom surface.

It can be seen, accordingly, that the bucket construction described above causes material cutaway from the stockpile by the cutting edge 13 of a guide face 12 to be guided inwards into the carrier bucket as a resultofthe ploughshare-like construction ofthe guide faces, and to come to rest here, in front of the guide face, on thefloorofthe preceding carrier bucket. As the charge increases, the material also passes onto the middle of the floor and from here is abletopassthroughtheopening 15 defined bythe inner edge(s) 14 of the guide face(s) 12 and onto the central region ofthe floor ofthe carrier bucket in question. In contrast to known constructions, each guide face thus conveys material, not only onto the floor of the preceding carrier bucket, but also onto the floor of its own carrier bucket. This means that not only is there an improvement in the filling ratio of the carrier bucket but also, because the partition walls between buckets have been dispensed with, there is a not inconsiderable reduction in the continuously revolving mass of the conveyor, thereby saving effort and energy for operation.

The deflectorfaces 16 assist in improving thefilling ratio ofthe buckets by preventing material from spilling over the tops of the buckets in the region of the guide faces 12 whiiethe use of thesupporting structure 17 to link each bucket to the conveyor chain assists in the provision of a simple, low-mass construction using only a few individual parts and, thereby, in reducing the amount of energy required for operation.

Claims (13)

1. A device for clearing a stockpile of bulk material, comprising an endless conveyor having a plurality of carrier buckets each of which has at ieast oneguidefacewith a cutting edge arranged, in use, to penetrate the material ofthe stockpile, there being an opening in the bucketthroughwhich material re moved from the stockpile by the guide face can pass into the bucket.

2. A device as claimed in claim 1, in which the guide face is arranged at the front of the bucket and the lower edge of the guide face extends obliquelyforwards in the conveying direction.

3. A device as claimed in claim 2, in which the floor of the bucket extends across the entire width, and as faras the tip, ofthe guide face.

4. A device as claimed in claim 2 or claim 3, in which the inner edge of the guide face definesthe opening in the bucket.

5. A device as claimed in a ny one of the preced- ing claims, in which a forwardly-directed deflector face is formed at the top edge of the guide face.

6. A device as claimed in any one of the preceding claims, suitableforclearing a longitudinal stockpile, in which the carrier buckets are constructed symmetrically with respect to the longitudinal axis.

7. A device as claimed in claim 6, in which each bucket has two guide faces, the inner edges ofwhich define the sides of the opening and which are arranged symmetrically with respect to the longitudinal axis.

8. A device as claimed in anyone of claims 1 to 5, suitable for clearing a circularstockpile, in which the carrier buckets are constructed with one guide face and with a side wall which extends in the conveying direction and which defines the other side of the opening.

9. A device as claimed in claim 5, in which the or each deflector face is joined to a supporting structure by means of which the carrier bucket is linked to a conveyor chain.

10. A device as claimed in anyoneofthepreceding claims, in which the guide face is arranged to direct material removed from the stockpile into the preceding carrier bucket.

11. Adevice as claimed in anyone ofthe preceding claims, in which the floors of the carrier buckets form a continuous supporting surface for material removed from the stockpile.

12. A device as claimed in any one ofthe preceding claims, in which theconveyor iscarried bya bridge which is movable in the direction ofthe stockpile and which spans the base of the stockpile.

13. A device for clearing a stockpile of bulk material, substantially as described herein with referenceto, and as shown in, Figures 1,3 and 5 or Fig- ures 2 to 4 and 6to 8 ofthe accompanying drawings.