WO2001045994A1 - Hopper discharge station - Google Patents

Abstract

The invention concerns a hopper discharge station for hoppers (34) each having a hopper body (36) and a bottom (38) which is pivoted to the body and carries rail wheels (40). The discharge station of the invention includes an excavation (14) which is traversed by a rail track (12) that includes a track section (22) which can move downwardly from a normal position in which it is aligned with the remainder of the rail track. This allows the bottom of a hopper (34) to pivot open for gravitational discharge of the contents of the hopper into the excavation. Means (28, 52, 56, 102) are provided for raising the track section (22) to the normal position thereby to pivotally close the bottom of the hopper (34). Means (30, 32) are also provided for supporting the hopper body (36) over the excavation (14) when the track section (22) moves downwardly.

Description

"HOPPER DISCHARGE STATION"

BACKGROUND TO THE INVENTION

THIS invention relates to a hopper discharge station at which mine hoppers can be discharged

So-called Rockflow Hoppers have been known for many years A hopper of this type has an ore carrying body defined by side and end walls and a pivoted bottom structure The rail wheels on which the hopper runs in normal use are mounted to the bottom structure which is pivoted to the remainder of the hopper about an axis transverse to the travel direction The bottom structure also carries a central so-called "bull wheel" between the normal rail wheels

A Rockflow Hopper is discharged under gravity at a specially designed discharge station at which there is an excavation beneath the level of the normal rails The normal rail track terminates on either side of the excavation while a central bull wheel rail extends through and follows the contour of the excavation In addition there is a robust supporting frame spanning the excavation and carrying a series of spaced apart support wheels elevated above the level of the normal rail track on either side of the track The hopper and tractive locomotive are fitted with laterally projecting flanges which can rest and ride on the support wheels

In use the locomotive and hopper train move continuously through the discharge station Each vehicle in the train leaves the rail track on one side of the excavation traverses the excavation on the support wheels and thereafter regains contact with the rail track on the opposite side of the excavation As each hopper moves over the excavation the bull wheel picks up and follows the bull wheel rail and the bottom of the hopper pivots downwardly into the excavation As the bottom of the hopper swings open the hopper contents discharge under gravity into the excavation and eventual chute or pass Rockflow Hoppers of the type described above operate extremely well and reliably in practice However a major drawback is the cost and complexity of the discharge station and, in particular, the size and cost of the excavation which is required to achieve the discharge operation

Furthermore, the support wheels at the discharge station are required to carry the combined weight of the locomotive and loaded hoppers resulting in considerable maintenance costs Insufficient maintenance could result in either the locomotive or the hoppers falling into the excavation There is also a reluctance on the part of the locomotive drivers to drive over a discharge station with no rails

Another drawback of the Rockflow Hopper described above is the inability of the train of hoppers to travel back over the excavation after discharge There is also the potential danger that other rolling stock may not be fitted with laterally projecting flanges, and may fall into the excavation

SUMMARY OF THE INVENTION

According to the present invention there is provided a hopper discharge station for hoppers each having a hopper body and a bottom which is pivoted to the body and carries rail wheels, the discharge station comprising an excavation traversed by a rail track that includes a track section which can move downwardly from a normal position in which it is aligned with the remainder of the rail track to allow the bottom of a hopper, the rail wheels of which are on that section, to pivot open for gravitational discharge of the contents of the hopper into the excavation, means for raising the track section to the normal position thereby to pivotally close the bottom of the hopper, and means for supporting the hopper body over the excavation when the track section moves downwardly ln the preferred embodiments, the movable track section is pivoted relative to a remainder of the rail track, most preferably about an axis transverse to the direction of movement of a hopper through the discharge station

In some embodiments, an hydraulic cylinder is provided for lowering and raising the track section

In other preferred embodiments, the discharge station is arranged for the movable track section to move downwardly under gravitational forces when a hopper is located on the track section and which comprises a counterweight system to raise the track section to its normal position after discharge of the hopper contents It may include releasable latching means for latching the track section releasably in its normal position The latching means may be arranged to be released automatically by a hopper, typically in a train of hoppers, arriving at the discharge station, whereby the hopper, or each hopper in the train, is discharged automatically at the discharge station Conveniently the latching means is arranged to be released by a trigger formation on each hopper The latching means may be arranged to latch the track section automatically in its normal position after the track section has been raised to that position after discharge of a hopper

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which

Figure 1 diagrammatically illustrates a hopper discharge station according to the invention with a hopper at the station prior to discharge,

Figure 2 shows a view similar to that of Figure 1 , during discharge of the hopper, Figure 3 diagrammatically illustrates a part of a second embodiment of the invention;

Figure 4 diagrammatically illustrates a third embodiment of the invention;

Figure 5 diagrammatically illustrates the automatic unlatching apparatus forming part of the Figure 4 embodiment in a cross-sectional view in the track direction;

Figure 6 shows a side view of a fourth embodiment;

Figure 7 shows another side view of relevant components of the fourth embodiment, the hoppers being omitted in the interests of clarity of illustration;

Figure 8 shows an end elevation of the components illustrated in

Figure 7;

Figure 9 shows a diagrammatic side view of the latching mechanism of the fourth embodiment prior to unlatching of the pivoted track section;

Figure 10 shows a diagrammatic plan view of the latching mechanism seen in Figure 9;

Figure 11 shows a diagrammatic side view of the latching mechanism of the fourth embodiment on unlatching of the pivoted track section;

Figure 12 shows a diagrammatic plan view of the latching mechanism on unlatching of the pivoted track section; and Figure 13 shows how a hopper can move in a reverse direction past the latching mechanism without unlatching the pivoted track section

DESCRIPTION OF EMBODIMENTS

Figures 1 and 2 diagrammatically illustrated an underground hopper discharge station 10 according to a first embodiment of this invention The hopper discharge station is served by a rail track 12 consisting of the normal, spaced apart rails The rail track 12 spans across an excavation 14 formed in the rock mass 16 beneath the track As illustrated, the excavation has a downwardly tapering upper section 18 leading to a relatively narrow chute or ore pass 20

The track 12 includes a track section 22 which is connected pivotally to the remainder of the track at a pivot axis 24 The track section 22 includes a pair of rails mounted on a supporting structure 26 A double acting hydraulic cylinder 28 acts between the track section 22 and a side of the excavation 14

Mounted alongside the rail track 12 and spanning across the excavation 14 is a support structure 30 On each side of the track the structure carries a row of spaced apart rollers or wheels 32 elevated some distance above the track

The numeral 34 indicates a hopper The hopper has a hopper body 36 consisting of side and end walls and a bottom 38 on which rail wheels 40 are mounted The bottom 38 is pivoted to the hopper body at an axis 42 Extending lengthwise along each side wall of the hopper body is a laterally projecting flange 44 Those skilled in the art will recognise that the hopper 34 is similar in many respects to a known Rockflow Hopper, but it will also be noted that the hopper does not include a bull wheel as is conventional on Rockflow Hoppers ln Figure 1 , the cylinder 28 is extended to raise the track section 22 into alignment with the remainder of the track 12 The hopper 34, which is one hopper in a train of hoppers, has been driven, by a locomotive (not shown) onto the track section and is stopped there for discharge of its contents to take place In this position, the flanges 44 may rest on the rollers 32 and the rail wheels 40 rest on the track section 22

The cylinder 28 is retracted to lower the track section 22 pivotally about the pivot axis 24 This is shown in Figure 2 As the track section moves downwardly, the bottom 38 of the hopper swings open to allow the hopper contents to discharge under gravity into the excavation It will be understood that the ore fragments which are discharged from the hopper fall directly into the chute or ore pass 20 When the track section 22 is lowered the hopper body remains at its original elevation, or is lowered slightly, supported by the interaction of the flanges 44 and the rollers 32

After the hopper has fully discharged, the cylinder 28 is again extended to raise the track section into alignment with the remainder of the track 12 again The hopper can then be driven forwardly through a distance chosen to bring the next hopper in the train into the discharge position As the hopper moves off the track section 22 the flanges 44 leave the rollers 32 and the hopper is once again fully supported by the track 12

The direction in which the hopper train moves through the discharge station 10 is indicated with the reference numeral 46 and it will be noted that the pivot point 42 is towards the leading end of the hopper

It is preferred that when the track section 22 is raised to its Figure 1 position after a discharge operation, the free end 48 is locked to the end 50 of the rail track This avoids the situation that the hydraulic cylinder 28 has to carry the weight of the track section and loads imposed thereon Any suitable locking means may be used Typically, the arrangement will be such that the locking means is released automatically to allow the track section 22 to be lowered when a hopper discharge operation is initiated

The configuration illustrated in Figure 1 is but one of many possible variants within the scope of the invention For instance instead of a track section 22 which is pivotally mounted, it would be possible to have a track section which is completely separable from the remainder of the rail track Suitable means will then be provided to raise and lower the entire track section relative to the remainder of the rail track, possibly with the track section remaining parallel to the remainder of the track throughout

Figure 3 diagrammatically illustrates a second embodiment of the invention which also makes use of a double acting hydraulic cylinder In this case, the cylinder 52 acts between the side of the excavation and a pivot joint 54 in a linkage 56 consisting of rigid links 58 and 60 The link 58 is pivoted at its opposite end to a fixed structure 62 and the link 60 to the track section 22

In the broken line position seen in Figure 2, the cylinder 52 has been retracted to lower the track section 22 pivotally In the full line position, the cylinder has been extended to raise the track section 22 into alignment with the remainder of the track 12 It will also be noted that in the latter position the joint 54 has gone over-centre, thereby locking the track section in its raised position To lower the track section again requires the cylinder to pull the joint 54 through the over-centre condition

In all embodiments illustrated herein the bottom of the hopper pivots relative to the hopper body about an axis which is transverse to the direction of hopper travel It is also within the scope of the invention for the hopper bottom to be pivoted to the hopper body about a longitudinal axis i e an axis extending in the direction of travel It will be understood that in this case, the movement of track section during raising and lowering will be such as to accommodate the required swinging movement of the hopper bottom In another variant, the flanges 44 on the hopper body could be replaced by rollers or wheels with the support structure at the sides of the rail track providing a surface for the rollers or wheels to locate on Alternatively any other form of support system to hold the hopper body in an elevated position above the excavation during discharge could be used There may, for instance, be interacting slides on the hopper body and at the sides of the rail track

As stated previously, any suitable type of raising and lower means to raise and lower the track section can be used In one possible alternative, a winch, acting through a cable and pulley system, could be used

A third embodiment is illustrated in Figure 4 In this Figure, components corresponding to components in the previous Figures are designated with the same reference numerals

In Figure 4, one end of a cable 51 is attached at a point 53 to the supporting structure 26 of the track section 22 which is mounted for pivotal movement about the pivot axis 24 It will be noted that the pivot axis 24 in this embodiment is located at a low elevation on the structure 26 The cable 51 passes over pulleys 54 and its opposite end is connected to a counterweight 56 in the upper section 18 of the excavation 14

Figure 5 illustrates an automatic latching and unlatching system which can be used in the third embodiment of Figure 4 Details of the system are omitted from Figure 4 in the interests of clarity of illustration The system includes a pair of ramp structures 60 which are located on opposite sides of the rail track Each of these structures includes an inclined ramp surface 62 supported by a crank lever which has arms 64 and 66 and which is pivoted on an axis 68 In an elevated position of the track section 22, the arm 66 contacts and supports the underside of a plate 70 which forms part of the support structure 26 and which carries the rails 22 1 , 22 1 which make up the track section 22 It will be understood that pivotal movement of the ramp surface and crank lever in the direction 72 will move the arm 66 away from the underside of the plate 70 thereby releasing the track section 22

This embodiment is designed to operate with continuous movement of the hopper tram through the discharge station 10 Referring to Figure 4, each hopper has lateral projections 74 on opposite sides thereof towards the rear of the hopper When each hopper reaches the discharge position on the track section 22, as is the case for the hopper designated 34 1 , the lateral projections on the hopper contact the ramp surfaces 62 and cause them and the crank levers to pivot in the directions 72, thereby releasing the track section 22 for downwardly pivotal movement about the axis 24

The crank levers, or alternatively the lateral projections 74 on the hopper can be spring loaded to allow the hoppers to return back over the discharge station without releasing the track section 22, thereby allowing passage of the tram in either direction, which is not possible with the present form of rockflow hoppers The crank levers can be designed to pivot out of the operational position thus preventing discharge from time to time should this be required

As viewed in Figure 4, the clockwise force moment which is applied to the rail section 22 by the counterweight 56 through the cable 50, and which tends to hold the rail section in its elevated position, is overcome by the anticlockwise force moment which is attributable inter alia to the mass of the track section and the hopper bottom and hopper contents as applied through the hopper wheels 40 As a result, once the track section 22 has been released by the latching and unlatching system, it pivots downwardly in an anticlockwise sense to the broken line position in Figure 4, allowing gravitational discharge of the hopper contents to take place

The speed with which the hopper train moves through the station 10 is such that by the time each hopper approaches the end of the track section 22, and before the next hopper has moved onto that section, there has been complete discharge of the hopper contents The mass of the counterweight 56 is selected such that the clockwise force moment which it applies to the track section now overcomes the opposing force moment which is of course reduced as a result of the absence of the hopper contents and the movement of the hopper wheels 40 towards the pivot axis 24

The track section is accordingly pivoted upwardly again to the full line position, closing the hopper bottom When the track section reaches the full line position the crank levers of the latching and unlatching system return to the illustrated position to latch it in position The process as described above is repeated on arrival of the next hopper at the designated position

It is believed that the invention as described above addresses the problem of high cost of the discharge station In particular, those skilled in the art will appreciate that the excavation 14 can be considerably smaller than that traditionally required It is also believed that the absence of a bull wheel rail of inverted camel-back shape extending through the discharge station will reduce the cost of the station It is also believed that having normal rails over the excavation will greatly enhance safety

Figures 6 to 13 illustrate a fourth, currently preferred embodiment which, like the embodiment of Figure 4, makes use of a counterweight system to return the movable rail section to its normal position after a discharge operation has taken place In these Figures, components corresponding to those of the earlier embodiments are designed by like numerals Details of the actual excavation and ore chute or pass are omitted from these Figures

In Figure 6 the track section 22 extends past the axis 24 at which it is pivoted and includes a pair of arms 100, on either side of the normal rail track, carrying counterweights 102 The counterweights 102 are located in respective cages 104 at the sides of the normal rail track The cages 104 are provided to prevent accidental injury to persons near to the counterweights The full lines in Figure 6 show the track section 22 raised to a normal, horizontal orientation, aligned with the rest of the rail track while the broken lines show the track section lowered pivotally to an orientation in which discharge of the hopper 34 takes place

As in the embodiment of Figure 4, discharge of the hoppers 34 in a hopper tram takes place automatically and continuously as the tram moves through the discharge station In its normal, horizontal orientation, the track section 22 is locked or latched in position It is unlatched from this position by a latching mechanism 106 described below in more detail

Also as in the embodiment of Figure 4, the arrangement is such that the weight of the hopper bottom or door 38, together with the weight of the hopper contents acting thereon, is sufficient to overcome the upward pivotal force applied to the track section 22 by the counterweights with the result that the door opens to allow discharge of the hopper to take place As soon as full discharge has taken place, the upward pivotal force attributable to the counterweights swings the track section 22 to the normal, horizontal orientation, thereby closing the door 38 It should be understood that the door 38 could be opened via a control mechanism rather than automatically under the influence of the weight of the hopper The control mechanism could include safety features to prevent the door from opening in a uncontrolled manner

Figures 7 and 8 illustrate the pivoted track section 22, counterweights 102 and support structure 30 in more detail, but omit the hoppers 34 themselves in the interests of clarity of illustration As illustrated, the structure 30 supports a series of inclined rollers 32 which interact with outwardly projecting formations or flanges 44 on the hoppers, thereby to maintain each hopper in an elevated position as the hopper traverses the discharge station

A feature of the embodiment of Figures 6 to 13 is a pair of downwardly extending brackets 108 carrying stops 110 at their lower ends The brackets 108 are mounted in a fixed manner at the sides of the excavation and so do not move when the track section 22 is unlatched and descends pivotally. At its sides the track section 22 carries downwardly extending shock absorbers 1 12 Downward pivotal movement of the track section 22 is arrested at a limit position by abutment of the shock absorbers 1 12 against the stops 1 10 The shock absorbers also serve to cushion the impact at the limit position.

Figures 9 to 13 illustrate the latching mechanism 106 which is used to unlatch the track section 22 when a hopper is in the correct position for discharge of its contents to take place. Referring to Figure 9, each hopper 34 carries triggers 114 in the form of an outwardly extending, ramped flanges on either side. The trigger mechanism also includes, on each side of the track section 22, a longitudinally slidable structure 1 16. Pivots 120 are mounted on fixed, transverse shafts 1 18 The triggers 114 on the hoppers are aligned with the upper ends of the pivots 120. The lower end of each pivot 120 carries a transverse pin 122 which rides in a curved slot 124 in the structure 116 and is formed with a hook 126. One end of a tension coil spring 128 engages the hook 126. The other end of the spring 128 is attached to the structure 116.

The track section 22 carries laterally projecting rollers 130 which, in the normal latched position of the track section, rest on undercut support formations 131 of the structure 1 16 A compression coil spring 132 acts between a fixed end plate 134 and the end of the structure 1 16 remote from the pivots 120.

In Figures 9 to 12, the hopper 34, details of which are omitted in the interests of clarity, is moving from right to left Figures 9 and 10 illustrate the situation when the triggers 1 14 have just contacted the upper ends of the pivots 120, which are maintained in a vertical orientation by the action of the spring 128. Further movement of the hopper to the left causes the pivots 120 to rotate in a counterclockwise sense. The pins 122 are at the right ends of the slots 124, with the result that the structure 116 is pushed to the right against the bias of the compression spring 132. The structure 116 moves to a position in which the rollers 130 are no longer supported by the formations 131 This unlatches the track section 22 and allows it to pivot downwardly under gravity, thereby initiating the discharge of the hopper contents This is illustrated in Figures 1 1 and 12

When discharge of the hopper contents has taken place and the track section 22 is pivoted upwardly again by the action of the counterweights 102, the rollers 130 strike the inclined surface 136 The sideways component of force applied to the structure 1 16 moves it to the right against the bias of the spring 132 As soon as the rollers have cleared the tips of the support formations 131 , the springs 132 return the structures 116 to the left, once again locating the formations 131 beneath the rollers and thereby latching the track section 22

The mechanism described above also incorporates auxiliary latches 140 located alongside the structure 1 16 and each pivoted about a fixed axis 142 When the structure 116 has moved to the unlatched position seen in Figures 1 1 and 12, the latches 140 drop into slots 144 in the structure 116 and prevent the springs 132 from moving the structures 116 to the left even after the triggers 114 have cleared the upper end of the pivots 120 When hopper discharge has taken place and the track section 22 is swung upwardly by the action of the counterweights 102, the rollers 131 displace the latches 140 upwardly to an unlatched position and thereby allowing the springs 132 to move the structures 1 16 to the left again as described above

It may happen that it is necessary to drive the hopper train in a reverse direction through the discharge station without unlatching of the track section 22 In Figure 13 the direction of hopper movement is from left to right In this situation, the triggers 114 on the hoppers once again contact and act upon the upper ends of the pivots 120 However in this case, the pivots 120 merely rotate clockwise against the bias of the springs 128 with their pins 122 riding in the slots 124 The pivots accordingly undergo lost motion without transferring any movement to the structures 1 16 As soon as the triggers 14 have cleared the upper ends of the pivots, the pivots are returned to their start positions by the springs 128

The hoppers 34 have been described only briefly Full details of the hoppers are described in a co-penmg patent application, filed simultaneously with the present application, and entitled "Hopper"

Claims

C LAI MS

1

A hopper discharge station for hoppers each having a hopper body and a bottom which is pivoted to the body and carries rail wheels, the discharge station comprising an excavation traversed by a rail track that includes a track section which can move downwardly from a normal position in which it is aligned with the remainder of the rail track to allow the bottom of a hopper, the rail wheels of which are on that section, to pivot open for gravitational discharge of the contents of the hopper into the excavation means for raising the track section to the normal position thereby to pivotally close the bottom of the hopper, and means for supporting the hopper body over the excavation when the track section moves downwardly

2

A hopper discharge station according to claim 1 wherein the movable track section is pivoted relative to a remainder of the rail track

3

A hopper discharge station according to claim 2 wherein the movable rail section is pivoted relative to the remainder of the rail track about an axis transverse to the direction of movement of a hopper through the discharge station

4

A hopper discharge station according to any one of the preceding claims and comprising an hydraulic cylinder for lowering and raising the track section 5

A hopper discharge station according to any one of claims 1 to 3 which is arranged for the movable track section to move downwardly under gravitational forces when a hopper is located on the track section and which comprises a counterweight system to raise the track section to its normal position after discharge of the hopper contents

6

A hopper discharge station according to claim 5 and comprising releasable latching means for latching the track section releasably in its normal position

7

A hopper discharge station according to claim 6 wherein the latching means is arranged to be released automatically by each hopper in a tram of hoppers arriving at the discharge station, whereby each hopper in the tram is discharged automatically at the discharge station

8

A hopper discharge station according to claim 7 wherein the latching means is arranged to be released by a trigger formation on each hopper

9

A hopper discharge station according to either one of claims 7 or 8 wherein the latching means is arranged to latch the track section automatically in its normal position after the track section has been raised to that position after discharge of a hopper