GB2269410A - Excavation apparatus - Google Patents

Abstract

An excavation apparatus for preparation of open cast land fill sites, comprises an excavation drum 10 for excavating a first layer of earth material 3, eg. a top soil layer, from a layer of sub soil 4; a drum 12 which cooperates with the drum 10 to reduce the size of large stones; a storage tank 5 for storing collected earth material; and a conveyor 6 for moving the earth material from the excavator drum to the storage tank. The apparatus can be self propelled by means of a chassis 8 and track assembly 9, which is motor driven. The apparatus may provide a substantially flat sub-soil layer, after excavation of a top soil layer, and reduce the amount of mixing of material between layers during excavation of a site. <IMAGE>

Description

EXCAVATION APPARATUS The present invention relates to excavation apparatus.

In the preparation of green field sites for open cast mining or quarrying, different layers of earth material need to be skimmed from the surface of the land and stored separately in separate areas adjacent to a crater region to be mined or quarried. When the mining or quarrying operation in the crater is complete, the crater is often lined with clay material, filled with domestic and/or industrial waste, capped with clay material and then restored for use as agricultural land. Restoration comprises re-laying the stored layers of earth material in their original order on top of the quarried region and landscaping the site.

To obtain agricultural land of acceptable quality, in the initial skimming operation, various layers of soil, sub-soil and overburden need to be skimmed separately and stored in separate storage regions.

Typically a top soil layer is of a depth six inches to one foot and over-lies a sub-soil layer of depth around two feet. The top soil and sub-soil layers lay on top of an overburden layer which can be in the range six to ten feet. The thicknesses of each of the soil, sub-soil and overburden layers varies from region to region depending on geological conditions.

Each layer is removed by conventional excavation apparatus, for example a back-hoe excavator. The top soil is excavated by a bucket on the back-hoe excavator and loaded into a dumper truck, which transports the top soil to a pile at the edge of the crater region. The whole of the top soil layer covering the desired crater region is removed by repeated filling of such dumper trucks. Then, the sub-soil layer is similarly removed and stored in a different place. Similarly, the overburden layer is removed and stored in another place. Each of the storage piles are then shaped using earth moving apparatus, for example, a bull dozer, to form tidy storage sites.

The above operation has a problem in that the backhoe machine is not capable of removing the top soil uniformly to expose a smooth upper sub-soil surface.

Portions of the sub-soil are unavoidably scooped up with the top soil and stored with the top soil. Also, portions of the top soil are left on the upper surface of the subsoil so that when the sub-soil is removed parts of the top soil are mixed in with the stored sub-soil. A rough, pitted and uneven exposed sub-soil surface is left.

Excavation using back hoe apparatus cannot distinguish between the top soil and sub-soil at the interface between the two, and an undesirably uneven exposed subsoil surface results. Thus, when the sub-soil is excavated, pockets of top soil are lost into the subsoil.

There is a similar problem in excavating the sub-soil at the interface between the sub-soil and the overburden layer. An uneven overburden layer results.

Where the ground is stony, stones and rocks are unavoidably excavated with the stored top soil, sub-soil and overburden during excavation. Stones or rocks which were originally in the overburden or sub-soil layers become mixed in with the top soil. During restoration, where~stones are mixed in with the top soil, sub-soil and overburden layers, often it is impracticable to restore the layers without having stones of a significant size mixed into the top soil and sub-soil layers. Stones in the top soil layer makes the land of poorer quality for agricultural use than originally, since the stones interfere with ploughing and other agricultural operations.

To improve the quality of the finally restored land, during restoration or skimming, gang labour is used to manually pick out stones from the top soil or sub-soil so that the restored sub-soil and/or top soil can have fewer stones. Such gang labour is expensive.

Conventionally, where separation of stone from excavated top soil, sub-soil or overburden is required, to improve the quality of restored land, and the yield of stone which can be sold, the respective top soil, sub-soil or overburden layers are each skimmed using conventional excavators as above-mentioned, and transported to a separating machine.

For example, where the top soil has been skimmed, the separating machine separates out stone from the top soil and produces separate piles of top soil and stone. Each of these piles needs then to be transported to its respective storage site. This operation has a disadvantage of numerous unloading and loading operations of the skimmed layer material, for example loading the top soil from the excavator into a dumper truck, unloading the dumper truck into either a pile near the separating machine or directly into the separating machine, loading the separated top soil from the separating machine into another dumper truck to be then unloaded at a storage site and similarly loading the separated stone material from the separating machine or a pile near the crusher into a dumper truck, to be stored separately at stone storage site or delivered direct to a customer.

A similar operation is carried out for the sub-soil layer.

Another type of conventional excavator is a wheeled scraper machine such as used for motorway construction.

Such scrapers comprise a towed trailer having an adjustable blade for skimming the top surface of a land site. These scrapers can produce a smooth exposed surface where conditions allow, but have the disadvantage that they will not operate in stony ground because the blade becomes snagged on the stones.

Specific embodiments of the present invention aim to address some of the above problems.

According to one aspect of the present invention there is provided an excavation apparatus comprising an excavation means for excavating a layer of earth material, and a reducing means for reducing said earth material into particulate components.

Said reducing means may comprise first and second drums having a nip therebetween.

Said reducing means may further comprise an impact member against which said earth material is thrust for reducing said material.

According to another aspect of the present invention, there is provided an excavation apparatus comprising an excavation means for excavating a layer of earth material and a separation means for separating out particulate components of said excavated material.

Preferably, said separation means comprises a vibratable grill, grid or riddle.

Said separation means may comprise a conveyor belt.

Preferably, the excavation apparatus is capable of excavating a strip of earth material of a substantially constant thickness.

Preferably, said excavation means comprises a rotatable drum having a plurality of projecting members arranged to dig into a said layer of earth material.

Said projecting members may be teeth, picks or flails.

Preferably, said excavation apparatus further comprises collection means for collecting said earth material.

Preferably, said collection means comprises a scraper member arranged to scrape along an upper surface of an exposed earth material layer to leave a substantially smooth exposed surface.

Said collection means may comprise a rotating auger.

Preferably, said collection means further comprises a conveyor means for conveying collected earth material away from a point of excavation.

Said collection means may include a rotatable lift or feed roller to lift material onto said conveyor means.

Preferably, said excavation apparatus further comprises a storage means for storing a quantity of excavated material.

Preferably, said storage means comprises one or more individual containers.

Preferably, said one or more containers are detachably mounted on said apparatus.

Said storage means may comprise a bin having first and second container portions.

Preferably, said excavation apparatus further comprises emptying means for emptying one or more said storage means.

Preferably, said emptying means comprises at least one conveyor belt.

Preferably, said excavation apparatus is self propelled.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 shows a first excavator apparatus according to a first embodiment of the present invention; Figure 2 shows further details of the first excavator; Figure 3 shows a storage tank arrangement according to a second embodiment of the present invention; Figure 4 shows a rotating drum arrangement according to a third embodiment of the present invention; Figure 5 shows a roll assembly arrangement according to a fourth embodiment of the present invention; and Figure 6 shows a second excavator apparatus according to fifth embodiment of the present invention.

Referring to Figure 1, a first excavator apparatus 1 comprises excavation means 2 for excavating a first layer of earth material 3 (for example a top soil layer) from a sub layer or second layer 4 of earth material (for example a sub-soil layer), storage means 5, for example a container tank or skip having forward and rearward compartments for storing collected earth material, collection means 6 for conveying the collected material from the excavation means to the storage means, propulsion means 7 for propelling the whole apparatus, and a suspension means comprising a chassis 8 and a track assembly 9.

The earth excavation means 2 comprises a first rotating drum 10 which rotates in a direction so as to bite into and lift the first layer of earth material 3 upwardly as shown in Figure 1. The drum 10 is adjustable by means of hydraulic rams 16 mounted to the chassis to alter the depth to which the earth material is excavated.

The drum 10 is provided with a plurality of teeth 11, which'arse for example teeth of a hard metal material such as manganese steel. The excavation means 2 further comprises a second rotating drum 12 rotating in an opposite sense to the first rotating drum to urge the earth material 3, which has been lifted by the first rotating drum, in a downward direction towards a nip 13 between the first and second rotating drums. A shield member 14 is provided to deflect any flying earth material in a downward direction and to help break up the material, and a scraper 15 is provided for scraping the exposed surface of the second layer to leave a substantially smooth surface.

In use, the first excavator machine moves in a forward direction (a direction left as shown in Figure 1) with the two rotating drums 10 and 12 contra-rotating with respect to each other. The drums are lowered with respect to the chassis 8 so that as the machine moves forward, the first drum 11 digs into the first layer 3 of earth material. As the machine progresses forward, the teeth on the first drum 10 attack the material of the first layer 3 and carry the earth in a clockwise (as shown in Figure 1) direction into the nip 13 between the two contrarotating drums. The action of the teeth on the first and second drums crushes and breaks any large stone material into smaller stone pieces.The excavated material, including the crushed stone, then passes into a space behind the two rollers and in front of the shield 14 to be collected by the conveyor belt 6, raised upwardly and dropped from an upper end of the conveyor belt and down a chute 18 on to a separating apparatus 19 which is for example a reciprocating grill/grid or riddle. A roller 22 in the space within the shield 14 behind the drums 10, 12 rotates in a clockwise (as shown) direction to lift the excavated material onto the conveyor 6. The riddle can be of a known type for example a spring mounted riddle driven by an electric motor which causes a reciprocating shaking action such that the earth material moves in a forward direction with respect to the machine. Any large stones fall into a forward bin 20 but finer material falls into a rearward bin 21 of the storage means 5.

Operation of the machine is controlled from a driving position 22 overlooking the drums.

Referring to Figure 2 of the accompanying drawings, further details of the first excavation machine are shown.

In addition to the hydraulic lowering ram 16, one or more tilt rams 30 are provided to tilt the shield, scraper and drum assembly backwardly or forwardly with respect to the chassis 8. Earth material 3 is shown schematically carried up the conveyor 6 and dropping from the upper end 31 of the conveyor 6. A conveyor ram 40 for adjusting the angle and position of the collection conveyor 6 is provided. Also shown, are first and second emptying conveyors 33, 34 respectively for emptying the rearward bin 21 and the forward bin 20. The emptying conveyors are operable independently of the collection conveyor 6.

In use, the excavator proceeds in a forward direction excavating and collecting a strip of earth material until either of the forward or rearward bins are full of top soil or stone material, at which point a truck can be driven alongside the excavator. The conveyor 33 and/or 34 can empty the respective bin into the truck.

The conveyors 33, 34 can be operated independently of each other to empty each respective bin as required. For example, in some soil conditions where little rock is found, the excavated earth layer 3 may comprise mainly soil, for example 95% upwards of the material will be soil. In this case, the rearward bin 20 will fill much more quickly than the forward bin 21 and will therefore need emptying more regularly. In other soil conditions in which the top soil contains a large quantity of stone, the forward stone bin will need emptying more regularly.

Each of the emptying conveyors 33, 34 may also be swung outwardly transversely to the direction of movement of the excavator and in an upward or downward direction by means of rams, chains, or other support means. Such rams and supports may be hydraulically operated.

Referring to Figure 3, an alternative arrangement of storage tank for an excavator is shown. In this embodiment, the storage tank comprises a large bin 50 having a smaller bin region 51. Earth material is dropped from a collection conveyor 6 onto a vibrating screen 53 for separating finer soil material from coarser material 54 e.g. stones (shown arrowed). A conveyor 55 is provided for emptying the coarse material 54 to a truck continuously, as the truck drives alongside the excavator apparatus. This feature allows a smaller volume of tank 51 for coarse material compared to the larger tank 50 for fine material. The larger fine material tank 50 can be emptied by means of a second conveyor 56.

Such a tank may be used in an operation in which an excavator drives through a strip or layer of earth material to separate out stones reducing them in size.

Residual sifted earth material in the bin 50 may be continuously unloaded behind the moving excavator by means of conveyor 56.

The vibrating screen is of conventional type, for example a reciprocating grid.

Such a tank embodiment may be suitable for soil which contains a low percentage of rock or stone.

Referring to Figure 4, a single rotating drum machine is shown. The machine comprises a single rotating drum 60 having a plurality of peripheral picks or flails 62. In this case, the drum rotates anti-clockwise as shown in Figure 4 such that the earth material layer 61 is dragged by the picks or flails underneath the rotating drum and upwardly into a space between the drum and a contrarotating auger 65. This contra-rotating movement aids pick up of the earth material which is then transported on the top of the conveyor 70 and back towards a storage bin (not shown).

The single rotating drum machine has a cutting edge 67 for providing a residual level upper surface exposed in the earth sub-layer. The rotating drum 62 is driven by a hydraulic drive motor 68 and gear box 69.

Referring to Figure 5, an alternative drum arrangement is shown. The alternative arrangement comprises a central drum 80 and side drums 81, 82 extending outwardly and angled with respect to the forward direction of travel of an excavator (the forward direction of travel is upwards in Figure 5). The drums 80, 81, 82 rotate in front of a shield 83. Excavated earth material is collected by a conveyor 89, and rotating augers 87 skim the surface of the exposed layer to leave a substantially smooth flat surface. The drums have a plurality of picks, teeth or flails 86.

Referring to Figure 6, a second excavator apparatus is shown. The second excavator apparatus is similar to the first excavator apparatus, having a chassis 100, a tracked suspension 101, a motor 103 for example a Diesel engine, a twin drum assembly 104, a conveyor 105 and a control cab 106. The twin drum assembly 104 is adjustable in height by means of a ram 110 connected to the chassis.

The second excavator differs from the first excavator in that two separate storage bins, first and second bins 120 and 121 are provided. The separate storage bins may be removable, and may be for example conventional skips.

In use, excavating operations of the second excavator are similar as described with reference to operation of the first excavator. However, in the second excavator, earth material is raised by the conveyor 105 to fall upon a vibrating riddle grill, or grid 109 driven mechanically, or by an electric motor 111. Finer material falls into the first bin 120, and coarser material eg stones falling into the second bin 121. Rather than empty each bin by means of a separate conveyor as in the first excavator, in the second excavator, each bin may be wholly removable from the excavator, and replaceable with an empty bin.

Alternatively, each bin may be fixed to the excavator and when either bin is full, the whole excavator apparatus may be driven to a point where of unloading the contents of either bin can be effected.

Preferred dimensions for either the first or second excavator are as follows. The excavation head may be around 3 metres wide and may be either two cylindrical drums as shown in Figures 1 and 2 of the accompanying drawings, a single drum as shown in Figure 4, or may be a compilation of drums and augers as shown in Figure 5. The height of a shield above a scraper 15 is preferably around 1.9 to 2 metres and the total height to the top of the cab is around 5 to 5.5 metres. The cab is preferably of dimensions length 1.5 metres and the total length of the apparatus is preferably around 9.5 metres. The length between axles at either end of the tracks is around 5.5 metres. In the second excavator, a rear half of the machine is of length of around 3 metres, defined from a centre of the first bin 120 to a rearmost periphery of the machine.A forward half of the machine (excluding the collection means) is of length around 3.5 metres measured from the centre of the bin 120. The drums are preferably of diameter around 80 centimetres.

Although a machine has been described having dimensions above, any one or more of these dimensions may be varied and specific embodiments of the invention are not restricted to having such dimensions, these being illustrative only.

The above-mentioned specific embodiments may advantageously provide a cleaner or smoother exposed subsoil surface and/or overburden exposed surface than hitherto available using conventional excavator apparatus.

Various of the above-mentioned specific embodiments may advantageously separate stone or rock material from top soil, sub-soil material, or overburden material, improving the yield of stone recovered from an open cast mine or quarry site.

Various of the above-mentioned specific embodiments may advantageously provide means for skimming for top soil in a more efficient manner than hitherto, such that the skimmed top soil contains a lower proportion of sub-soil and stone than hitherto possible.

Similarly, specific embodiments may improve the quality of sub-soil and/or overburden skimmed from a green field site.

Specific embodiments of the present invention may advantageously reduce the number of loading/unloading operations involved in separating stone from top soil, sub-soil, or overburden material.

The first and second rotating drums 10, 12, in the above described embodiment are shown as provided with a plurality of teeth, but in other embodiments may be provided with impeller blades, blow bars or the like.

Where teeth are shown in the above embodiments, alternatively picks, mounted in pick boxes maybe used.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (33)

1. An excavation apparatus comprising an excavation means for excavating a first layer of earth material from a second layer of earth material; and a reducing means for reducing said first layer of earth material into particulate components.

2. An excavation apparatus according to claim 1, in which said excavation means comprises a rotatable drum having a plurality of projecting members arranged to dig into a said layer of earth material.

3. An excavation apparatus according to claim 2, in which said projecting members are teeth, picks or flails.

4. An excavation apparatus according to claim 2 or 3, wherein said rotatable drum is arranged to rotate in a direction so as to bite into and lift a first said layer of earth material.

5. An excavation apparatus according to claim 2, 3 or 4, in which the drum is adjustable to alter the depth to which the earth material is excavated.

6. An excavation apparatus according to any one of claims 1 to 5, wherein said reducing means comprises first and second rotatable drums having a nip therebetween.

7. An excavation apparatus according to claim 6, in which the second drum rotates in an opposite sense to the first drum, to urge the earth material in a downward direction towards the nip.

8. An excavation apparatus according to any one of the preceding claims, further comprising a scraper for scraping along an upper surface of an exposed second layer of earth material, to leave a substantially smooth exposed upper surface.

9. An excavation apparatus according to claim 8, in which the scraper is adjustable with respect to a chassis of the excavator apparatus.

10. An excavation apparatus according to any one of the preceding claims, having a shield member to deflect excavated material in a downward direction and break up the material.

11. An excavation apparatus according to any one of claims 1 to 10, having a separation means for separating out particulate components of said excavated material.

12. An excavation apparatus according to claim 11, wherein said separation means comprises a vibrateable grill, grid or riddle.

13. An excavation apparatus according to claim 12, wherein said separation means comprises a conveyor belt.

14. An excavation apparatus according to any one of the preceding claims, further comprising collection means for collecting said earth material.

15. An excavation apparatus according to claim 14, wherein said collection means further comprises a collection conveyor for conveying collected earth material away from the excavation means.

16. An excavation apparatus according to claim 15, wherein a ram is provided for adjusting the angle and position of the collection conveyor.

17. An excavation apparatus according to claim 15 or 16, having a roller positioned behind the drum, the roller rotating to lift the excavated material onto the collection conveyor.

18. An excavation apparatus according to any one of the preceding claims further comprising a storage means for storing a quantity of excavated material.

19. An excavation apparatus according to claim 18, wherein said storage means comprises one or more individual containers.

20. An excavation apparatus according to claim 19, wherein said one or more containers are detachably mounted on said apparatus.

21. An excavation apparatus according to claim 18 or 19, wherein said storage means comprises a bin having first and second container portions.

22. An excavation apparatus according to any one of claims 18 to 21, further comprising emptying means for emptying one or more said storage means.

23. An excavation apparatus according to claim 22, wherein said emptying means comprises at least one conveyor.

24. An excavation apparatus according to claim 23, in which two emptying conveyors are provided, each operable independently of the collection means.

25. An excavation apparatus according to claim 23 or 24, in which the emptying conveyor(s) may be swung outwardly in a direction transversely to the direction of movement of the excavator apparatus, and/or in an upward or downward direction by means of rams, chains, or hydraulically operated means.

26. An excavation apparatus according to any one of the preceding claims, having a rotating auger which skims the surface of the exposed earth material layer to leave a substantially smooth surface.

27. An excavation apparatus according to any one of the preceding claims, which is controllable from a driving position overlooking the drum(s).

28. An excavation apparatus according to any one of the preceding claims, which is self propelled.

29. An excavation apparatus according to any one of the preceding claims, having a twin drum assembly which is adjustable in height by means of a ram connected to a chassis of the excavator.

30. An excavation apparatus according to any one of the preceding claims, in which the height of the shield above the scraper is about 2 m.

31. An excavator apparatus according to any one of the preceding claims, having a drum of diameter around 80 cm.

32. An excavator apparatus according to any one of claims 20 to 31, which may be driven to a point where unloading of the contents of a said container can be effected.

33. An excavation apparatus according to any one of the preceding claims capable of excavating a strip of earth material of a substantially constant thickness, to leave a substantially smooth exposed sub-soil or overburden surface.