WO2009004343A2

WO2009004343A2 - Excavator vehicle

Info

Publication number: WO2009004343A2
Application number: PCT/GB2008/002287
Authority: WO
Inventors: Gareth John Thomas
Original assignee: Gareth John Thomas
Priority date: 2007-07-03
Filing date: 2008-07-03
Publication date: 2009-01-08
Also published as: GB201118267D0; GB0803229D0; GB0712895D0; WO2009004343A3; GB2482261A; GB2450769A

Abstract

An excavator vehicle (1, 101) is provided, the excavator having a front and a rear, the excavator comprising a means for excavating material (9a, 9b, 109a, 019b) and two primary conveyors for the movement of excavated material (2a, 2b, 102a, 102b), each primary conveyor having a first portion associated with the front of the vehicle and each primary conveyor extending rearwardly, the excavator further comprising a jacking arrangement for securing the excavator vehicle, the jacking arrangement comprising a first jack (7, 107) extendible in a first direction and a second jack (14) extendible in a second direction, different from the first direction.

Description

Excavator vehicle

The present invention relates to an excavator vehicle, particularly but not exclusively the type of vehicle that is used to remove rock, coal or other hard substances from a substrate.

In accordance with a first aspect of the present invention, there is provided an excavator vehicle having a front and a rear, the excavator comprising a means for excavating material and two primary conveyors for the movement of excavated material, each primary conveyor having a first portion associated with the front of the vehicle and each primary conveyor extending rearwardly.

At least one of the primary conveyors may extend readwardly from the front of the excavator vehicle.

The excavator according to the first aspect of the present invention facilitates the provision of space between the two primary conveyors . Such space may be used to accommodate an excavating arm, for example. The space may also be used to accommodate other components, such as a jack.

It is preferred that the first portions of the two primary conveyors are mutually spaced. It is preferred that the two primary conveyors are mutually spaced along the majority of the length of (and further preferably along substantially the whole length of) the two primary conveyors. It is preferred that the two primary conveyors are substantially parallel to one another. At least one of the primary conveyors may be a belt conveyor, a push-belt conveyor or a screw conveyor.

The excavator vehicle may comprise an excavator main body (the excavator main body having a front and a rear) . The first portion of at least one of the primary conveyors may be located at or proximate to the front of the main body. It is preferred that the first portion of both of the primary- conveyors is located at or proximate to the front of the main body. At least one of the primary conveyors may extend to the rear of the main body.

The excavator vehicle may be provided with a secondary conveyor arrangement. It is further preferred that the two primary conveyors are arranged for the movement of excavated material to the secondary conveyor arrangement. The secondary conveyor arrangement may be arranged for the movement of excavated material to a lateral side of the excavator vehicle. The excavator may be provided with a plurality of unloading positions, with the secondary conveyor arrangement being arranged for the movement of excavated material to one or more of the plurality of unloading positions.

One may therefore unload material to one or more unloading positions at any given time. For example, the excavator may be arranged to deliver excavated material to a first unloading position at one time. The secondary conveyor arrangement may then be reconfigured so as to unload excavated material to a second unloading position. This reconfiguring may take the form of moving one or more components of the secondary conveyor arrangement. The secondary conveyor arrangement may be arranged so that when the second conveyor arrangement is in a first configuration, excavated material is deliverable to a first unloading position, and when the second conveyor arrangement is in a second configuration, excavated material is deliverable to a second unloading position. It is preferred that when the second conveyor arrangement is in a third configuration, excavated material is deliverable to a third unloading position. It is preferred that the secondary- conveyor arrangement is readily interchangeable between the first, second and optionally the third configurations. In each of the first and second (and third, if present) configurations of the secondary conveyor arrangement, the secondary conveyor arrangement may be fixed in position relative to the remainder of the vehicle.

Such interchangeability may conveniently be achieved by the second conveyor arrangement comprising a first secondary conveyor. The first secondary conveyor may be a delivery conveyor for delivering excavated material onto a collecting conveyor or into a collecting receptacle. Those skilled in the art will realise that such collecting conveyors and collecting receptacles are conventional and do not form part of the excavator of the present invention. A collecting conveyor is typically used to take excavated material away from the excavation site. The delivery conveyor may be an elongate conveyor. The delivery conveyor may typically have a first portion for receipt of excavated material and a second portion remote from the first portion. The second portion is typically raised compared to the first portion. This is to allow a collecting conveyor or receptacle to be placed below the delivery conveyor so that excavated material falling from the delivery conveyor is received by the collecting conveyor or receptacle. The excavated material may then be taken from the region from which it has been excavated.

In the first, second and optionally third configurations, the second portion of the delivery conveyor may be in mutually different positions. "Mutually different positions" typically means in mutually different positions relative to the primary conveyors. In each of the first, second and optionally third configurations, the position of the second portion of the delivery conveyor may be fixed relative to the primary conveyors. Thus, the position of the second portion relative to the primary conveyors may be different in the first and second configurations, but in each of the first and second configurations, the position of the second portion (relative to the primary conveyors) may be fixed.

In the first configuration, the second portion may be to one lateral side of the vehicle. In the second configuration, the second portion may be to a different lateral side of the vehicle or may be to the rear of the vehicle. It is preferred that in the second configuration, the second portion is to a different lateral side of the vehicle and in a third configuration, the second portion is to the rear of the vehicle.

The secondary conveyor arrangement may comprise a further secondary conveyor for moving excavated material to the delivery conveyor. The further secondary conveyor may move excavated material laterally. The excavator may comprise a first unloading position and a second unloading position. The first unloading position may be located on one lateral side of the excavator vehicle. The second unloading position may be located on another lateral side of the excavator vehicle. The secondary conveyor arrangement may be arranged for the movement of excavated material to both the first and second unloading positions.

The secondary conveyor arrangement may be arranged for the movement of excavated material to each of (i) a first unloading position located on one lateral side of the excavator and (ii) a second unloading position located on another lateral side of the excavator. The secondary conveyor arrangement may comprise a secondary conveyor, switchable between a first state in which said secondary conveyor may transfer material to the first unloading position and a second state in which said secondary conveyor may transfer material to the second unloading position. This is conveniently achieved by having a bidirectional conveyor. Bidirectionality may be achieved using a belt conveyor which is drivable in two directions (for example, by using a bidirectional motor or by using an idler gear to reverse the direction of travel of the conveyor) . Bidirectionality may be used to selectively move excavated material to the first unloading position or the second unloading position.

The secondary conveyor arrangement may comprise two secondary conveyors. A first secondary conveyor may be arranged for the movement of excavated material to the first unloading position and a second secondary conveyor may be arranged for the movement of excavated material to the second unloading position. Alternatively, the first and second secondary conveyors may each be switchable between a first state in which the first and second secondary conveyors may transfer material to the first unloading position and a second state in which the first and second secondary conveyors may transfer material to the second unloading position.

The excavator vehicle may comprise an apron for the receipt of excavated material. The apron may be, in use, associated with the front of the vehicle. The apron is preferably located at, or in proximity to, the front of the excavator main body (if present) . The apron is preferably arranged so that excavated material may be transferred from the apron to the primary conveyors. The excavator vehicle may be arranged so that the apron may act as a means for excavating material ., For example, the apron may be urged into the ground so that forward movement of the vehicle (or movement of a chassis to which the apron is attached) causes the apron to act as a shovel.

The means for excavating material may comprise an excavating attachment. The excavating attachment may comprise a shovel or bucket. The excavating attachment may comprise a cutter, such as a rotary cutter. The cutter may be suitable for excavating rock, coal or other hard material. The excavating attachment may _^be attached to an arm which is optionally attached to the excavator main body. The arm may be articulated. At least part of the arm may, in use, be received in the space between the two primary conveyors. The secondary conveyor arrangement may comprise one or more of a belt conveyor, a push-belt conveyor and a screw conveyor.

The excavator vehicle may comprise a ground-contacting means for moving the excavator vehicle. The excavator vehicle preferably comprises two ground-contacting means for moving the vehicle, each of the means for moving the excavator vehicle being associated with (and in spaced relationship with) a respective primary conveyor. A part of each of the primary conveyors may be proximate to the respective means for moving the excavator vehicle. Said parts of the primary conveyors may be movable away from the respective means for moving the vehicle. The excavator vehicle may be provided with means for moving said parts of the primary conveyors away from the respective means for moving the excavator vehicle .

It is preferred that at least one of the primary conveyors (and preferably each of the primary conveyors) is pivotally mounted so that said part of the primary conveyor is movable away from the respective means for moving the excavator vehicle .

At least one of (and preferably each of) the primary conveyors may be pivotally mounted at or proximate to the rear end of the respective primary conveyor.

The means for moving the vehicle may comprise a wheeled arrangement, the wheels being for contacting the ground and for moving the excavator vehicle. The means for moving the vehicle may preferably comprise a tracked arrangement, such as a caterpillar track arrangement. Excavated material may accumulate between the primary conveyor and a track, and this is undesirable. It is possible that such accumulation may result in jamming of one or both of the primary conveyor and the means for moving the vehicle so that one or both of these elements cannot be readily moved. Such jamming may cause damage to the jammed component if, for example, power is applied to the component when in a jammed state.

The excavator vehicle may be provided with a means for lifting the ground-contacting means for moving the vehicle out of contact with the ground. This may facilitate the cleaning of the excavator vehicle because if the means for moving the excavator vehicle is raised from the floor the means for moving the excavator vehicle may be operated or actuated without moving the vehicle. Such operation or actuation may, in certain circumstances, remove any material which was between the means for moving the vehicle and the respective primary conveyor.

The means for lifting the means for moving the vehicle may comprise one or more jacks, and preferable a plurality of jacks. Each jack may be hydraulic. The means for lifting the means for moving the vehicle from the ground may be capable of lifting the excavator vehicle from the ground such that there is no contact between the excavator vehicle (apart from the jacks, of course) and the ground.

The excavator vehicle may comprise a jacking arrangement for securing the excavator vehicle, the jacking arrangement comprising a first jack extendible in a first direction and a second jack extendible in a second direction, different from the first direction.

This jacking arrangement may secure the vehicle by extending the first jack in one direction so as to engage a surface of a rock face or the like (e.g. the ceiling of a mine chamber) and by extending the second jack in a different direction so as to engage a different surface of a rock face or the like (e.g. the floor of a mine chamber).

It is preferred that the second direction is substantially- parallel to the first direction. The second direction may be substantially opposite to the first direction.

The second direction may be coaxial with the first direction. This permits the rotation of the excavator vehicle about this axis.

It is preferred that the first jack is extendible away from an upper surface of the excavator vehicle. In this case, it is preferred that the second jack is extendible away from a lower surface of the excavator vehicle.

It is preferred that the first jack is extendible in a generally upwards direction and the second jack is extendible in a generally downwards direction. The "upwards" and "downwards" directions refer to the directions when the excavator vehicle is placed in a substantially horizontal orientation.

The excavator vehicle may be provided with a first set of additional jacks, the additional jacks of the first set being operable to extend in generally the same direction as the first jack. The .excavator vehicle may be provided with a second set of additional jacks, the additional jacks of the second set being operable to extend in generally the same direction as the second jack.

It is preferred that the second jack is capable of supporting the weight of the excavator vehicle. It is preferred that the second jack is operable to lift the excavator vehicle from the floor. This is particularly useful for working in environments with slippery floors and/or on sloping ground. It is preferred that the excavator vehicle comprises a chassis, and that the second jack is operable to lift the chassis from the floor. Any components attached to the chassis may also, therefore, be lifted from the floor.

The excavator vehicle may have a front and rear, and a first lateral side and a second lateral side.

The first jack may be extendible away from the first lateral side of the excavator vehicle, and the second jack may be extendible away from the second lateral side of the excavator vehicle. This arrangement may allow the vehicle to be secured, for example, between opposing walls of a chamber .

The jack arrangement facilitates the lifting of vehicle so that the means for moving the excavator (if present) is/are no longer in contact with the ground. Said part of the primary conveyor which is proximate to the respective means for moving the excavator vehicle may then be moved away from the respective means for moving the excavator vehicle. This facilitates the manual removal of any material which may have accumulated between said part of the conveyor and the means for moving the excavator vehicle. Alternatively, the means for moving the vehicle may be actuated, and such movement of the means for moving the vehicle may cause the shedding of some or all accumulated dirt.

It is preferred that the vehicle is provided with a chassis and the jack arrangement is provided with a third jack for moving the chassis when the first and second jacks have secured the excavator vehicle. The third jack may be located in a space provided between the two primary conveyors.

Those skilled in the art will realise that the third jack may move the whole of the vehicle but not the jacking arrangement. The conveyor, the means for excavating material, the apron (if present) and excavator main body (if present) may be associated with the chassis (for example, by being attached to the chassis) and so be movable by the third jack. The chassis may be slidably movable by the third jack. It is preferred that the third jack is arranged to be extendible in a substantially forward direction. This facilitates the forward motion of the primary conveyors and apron (if present) and facilitates the urging of an apron

(if present) into positive engagement with the ground, thus permitting the apron to act as a shovel, excavating material from the floor. The excavator may be provided with a slider arrangement as described below in relation to the excavator in accordance with the third aspect of the present invention. In accordance with a second aspect of the present invention, there is provided an excavator vehicle comprising a ground- contacting means for moving the excavator vehicle and a primary conveyor in spaced relationship from the means for moving the excavator vehicle, there being a part of the primary conveyor proximate to the means for moving the excavating vehicle, said part of the primary conveyor being movable away from the means for moving the excavator vehicle .

The excavator may be provided with means for moving said parts away from the means for moving the vehicle.

The primary conveyor may extend rearwardly, and optionally from the front of the vehicle.

It is preferred that the primary conveyor is pivotally mounted so that said part of the primary conveyor is movable away from the means for moving the excavator vehicle.

The primary conveyor may be pivotally mounted at or proximate to the rear end of the primary conveyor.

In this case, it is preferred that the excavator vehicle is provided with an apron for collection of excavated material. Movement of said part away from the means for moving the excavating vehicle may urge the apron towards the ground. In this case, the apron may act as a shovel, with forward motion of the excavator vehicle causing the apron to excavate material from the ground. The excavator vehicle may be provided with two primary conveyors, each being in spaced relationship with a respective ground-contacting means for moving the excavator vehicle, a part of each primary conveyor being proximate to the respective means for moving the excavator vehicle, the excavator being provided with means for moving each of said parts of the primary conveyors away from the respective means for moving the excavator vehicle.

It is preferred that the each of the primary conveyors is provided with a first portion associated with the front of the vehicle. It is preferred that the two primary conveyors are mutually spaced. It is preferred that the two primary conveyors are mutually spaced along the majority of the length of (and further preferably along substantially the whole length of) the two primary conveyors. It is preferred that the two primary conveyors are substantially parallel to one another.

At least one of the primary conveyors may be a belt conveyor, a push-belt conveyor or a screw conveyor.

The excavator vehicle may comprise an excavator main body (the excavator main body having a front and a rear) . The first portion of at least one of the primary conveyors may be located at or proximate to the front of the main body. It is preferred that the first portion of both of the primary conveyors is located at or proximate to the front of the main body. At least one of the primary conveyors may extend to the rear of the main body. The means for moving the vehicle may comprise a wheeled arrangement, the wheels being for contacting the ground and for moving the excavator vehicle. The means for moving the vehicle may preferably comprises a tracked arrangement, such as a caterpillar track arrangement. Excavated material may accumulate between the primary conveyor and a track, and this is undesirable. It is possible that such accumulation may result in jamming of one or both of the primary conveyor and the means for moving the vehicle so that one or both of these elements cannot be readily moved. Such jamming may cause damage to the jammed component if, for example, power is applied to the component when in a jammed state.

The excavator vehicle may be provided with a means for lifting the ground-contacting means for moving the vehicle out of contact with the ground. This may facilitate the cleaning of the excavator vehicle because if the means for moving the excavator vehicle is raised from the floor the means for moving the excavator vehicle may be operated or actuated without moving the vehicle. Such operation or actuation may, in certain circumstances, remove any material which was between the means for moving the vehicle and the primary conveyor.

The means for lifting the means for moving the vehicle may comprise one or more jacks, and preferable a plurality of jacks. Each jack may be hydraulic. The means for lifting the means for moving the vehicle from the ground may be capable of lifting the excavator vehicle from the ground such that there is no contact between the excavator vehicle (apart from the jacks, of course) and the ,ground. The excavator vehicle may comprise a means for excavating material. The means for excavating material may be substantially as described with reference to the excavator vehicle of the first aspect of the present invention.

The excavator vehicle may comprise an apron for the receipt of excavated material. The apron may be substantially as described with reference to the excavator vehicle of the first aspect of the present invention.

The excavator vehicle may comprise a jacking arrangement for securing the excavator vehicle, the jacking arrangement comprising a first jack extendible in a first direction and ^• a second jack extendible in a second direction, different from the first direction.

The jacking arrangement may secure the vehicle by extending the first jack in one direction so as to engage a surface of a rock face or the like (e.g. the ceiling of a mine chamber) and by extending the second jack in a different direction so as to engage a different surface of a rock face or the like (e.g. the floor of a mine chamber).

It is preferred that the second direction is substantially parallel to the first direction. The second direction may be substantially opposite to the first direction.

It is preferred that the first jack is extendible away from an upper surface of the excavator vehicle. In this case, it is preferred that the second jack is extendible away from a lower surface of the excavator vehicle. It is preferred that the first jack is extendible in a generally upwards direction and the second jack is extendible in a generally downwards direction. The "upwards" and "downwards" directions refer to the directions when the excavator vehicle is placed in a substantially horizontal orientation.

The excavator vehicle may be provided with a first set of additional jacks, the additional jacks of the first set being operable to extend in generally the same direction as the first jack. The excavator vehicle may be provided with a second set of additional jacks, the additional jacks of the second set being operable to extend in generally the same direction as the second jack.

It is preferred that the second jack is capable of supporting the weight of the excavator vehicle. It is preferred that the second jack is operable to lift the excavator vehicle from the floor. This is particularly useful for working in environments with slippery floors and/or on sloping ground.

The first jack may be extendible away from the first lateral side of the excavator vehicle, and the second jack may be extendible away from the second lateral side of the excavator vehicle. This arrangement may allow the vehicle to be secured, for example, between opposing walls of a ■ chamber . The excavator vehicle may comprise a ground-contacting means for moving the excavator vehicle (such as a tracked arrangement e.g. caterpillar tracks).

The excavator may also comprise a primary conveyor in spaced relationship from the means for moving the excavator vehicle, there being a part of the primary conveyor proximate to the means for moving the excavating vehicle, the excavator being provided with means for moving said part of the primary ^'conveyor away from the means for moving the excavator vehicle.

The jacking arrangement facilitates the lifting of vehicle so that the means for moving the excavator are no longer in contact with the ground. Said part of the primary conveyor may then be moved away from the means for moving the excavator vehicle. This facilitates the manual removal of any material which may have accumulated between said part of the conveyor and the means for moving the excavator vehicle. Alternatively, the means for moving the vehicle may be actuated, and such movement of the means for moving the vehicle may cause the shedding of some or all accumulated dirt.

It is preferred that the vehicle comprises a chassis and the jack arrangement is provided with a third jack for moving the chassis when the first and second jacks have secured the excavator vehicle. The third jack may be located in a space provided between the two primary conveyors.

Those skilled in the art will realise that the third jack may move the whole of the vehicle but not the jacking arrangement. The conveyor, the means for excavating material, the apron (if present) and excavator main body (if present) may be associated with the chassis (for example, by being attached to the chassis) so as to be movable by the third jack. The chassis may be slidably movable by the third jack. It is preferred that the third jack is arranged to be extendible in a substantially forward direction. This facilitates the forward motion of the excavator and apron (if present) and facilitates the urging of an apron (if present) into positive engagement with the ground, thus permitting the apron to act as a shovel, excavating material from the floor. The excavator may be provided with a slider arrangement as described below in relation to the excavator in accordance with the third aspect of the present invention.

The excavator vehicle may have a front and a rear, and may comprise a plurality of unloading positions, and a secondary conveyor arrangement arranged for the movement of excavated material to one or more of the plurality of unloading positions .

This arrangement allows excavated material to be delivered to more than one position around the excavator vehicle, which may be desirable when working in enclosed spaces in which it is not always possible to position a collecting receptacle or collecting conveyor to the rear of the vehicle or to one side of the vehicle.

One may therefore unload material to one or more unloading positions at any given time. For example, the excavator may be arranged to deliver excavated material to a first unloading position at one time. The secondary conveyor arrangement may then be reconfigured so as to unload excavated material to a second unloading position. This reconfiguring may take the form of moving one or more components of the secondary conveyor arrangement.

The secondary conveyor arrangement may be arranged so that when the second conveyor arrangement is in a first configuration, excavated material is deliverable to a first unloading position, and when the second conveyor arrangement is in a second configuration, excavated material is deliverable to a second unloading position. It is preferred that when the second conveyor arrangement is in a third configuration, excavated material is deliverable to a third unloading position. It is preferred that the secondary conveyor arrangement is readily interchangeable between the first, second and optionally the third configurations. In each of the first and second (and third, if present) configurations of the secondary conveyor arrangement, the secondary conveyor arrangement may be fixed in position relative to the remainder of the vehicle.

Such interchangeability may conveniently be achieved by the second conveyor arrangement comprising a first secondary conveyor. The first second conveyor may be a delivery conveyor for delivering excavated material onto a collecting conveyor or into a collecting receptacle. Those skilled in the art will realise that such collecting conveyors and collecting receptacles are conventional and do not form part of the excavator of the present invention. A collecting . conveyor is typically used to take excavated material away from the excavation site. The external conveyor is not part of the excavator of the present invention. The delivery- conveyor may be an elongate conveyor. The delivery conveyor may typically have a first portion for receipt of excavated material and a second portion remote from the first portion. The second portion is typically raised compared to the first portion. This is to allow a collecting conveyor " or receptacle to be placed below the delivery conveyor so that excavated material falling from the delivery conveyor is received by the collecting conveyor or receptacle. The excavated material may then be taken from the region from which it has been excavated.

In the first, second and optionally third configurations, the second portion of the delivery conveyor may be in mutually different positions. "Mutually different positions" typically means in mutually different positions relative to the primary conveyor. In each of the first, second and optionally third configurations, the position of the second portion of the delivery conveyor may be fixed relative to the primary conveyor. Thus, the position of the second portion relative to the primary conveyor may be different in the first and second configurations, but in each of the first and second configurations, the position of the second portion (relative to the primary conveyor) may be fixed. In the first configuration, the second portion may be to one lateral side of the vehicle. In the second configuration, the second portion may be to a different lateral side of the vehicle or may be to the rear of the vehicle. It is preferred that in the second configuration, the second portion is to a different lateral side of the vehicle and in a third configuration, the second portion is to the rear of the vehicle.

The secondary conveyor arrangement may comprise a further secondary conveyor for moving excavated material to the delivery conveyor. The further secondary conveyor may move excavated material laterally.

The excavator may comprise a first unloading position and a second unloading position. The first unloading position may be located on one lateral side of the excavator vehicle. The second unloading position may be located on another lateral side of the excavator vehicle. The secondary conveyor arrangement may be arranged for the movement of excavated material to both the first and second unloading positions.

The secondary conveyor arrangement may comprise a first secondary conveyor, switchable between a first state in which said first secondary conveyor may transfer excavated material to the first unloading position and a second state in which said secondary conveyor may transfer excavated material to the second unloading position. This is conveniently achieved by having a bidirectional conveyor. This may be achieved using a conveyor which is drivable in two directions (for example, by using a bidirectional motor or by using an idler gear to reverse the direction of travel of the conveyor) . It is therefore possible to deliver excavated material selectively to the first unloading position or the second unloading position.

The secondary conveyor arrangement may comprise two secondary conveyors. A first secondary conveyor may be arranged to transfer excavated material to the first unloading position and a second secondary conveyor may be arranged to transfer excavated material to the second unloading position. Thus, excavated material may be moved to the first and second unloading positions simultaneously.

Alternatively, the first and second secondary conveyors may each be switchable between a first state in which the first and second secondary conveyors may transfer material to the first unloading position and a second state in which the first and second secondary conveyors may transfer material to the second unloading position.

One or both of the first and second secondary conveyors may extend across the width of the excavator vehicle.

The secondary conveyor arrangement may be located at or proximate to the rear of the vehicle.

It is preferred that the excavator vehicle is provided with a primary conveyor for movement of excavated material to_ the secondary conveyor arrangement. The primary conveyor may have a first portion associated with the front of the excavator vehicle, and the primary conveyor may extend rearwardly i.e. away from the front of the excavator vehicle. The primary conveyor may extend rearwardly from the front of the vehicle.

It is preferred that the secondary conveyor arrangement is located generally rearwardly of the primary conveyor arrangement .

In accordance with a third aspect of the present invention, there is provided an excavator vehicle comprising a means for excavating material and a jacking arrangement for securing the excavator vehicle, the jacking arrangement comprising a first jack extendible in a first direction and a second jack extendible in a second direction, different from the first direction.

The excavator vehicle of the third aspect of the present invention may secure the vehicle by extending the first jack in one direction so as to engage a surface of a rock face or the like (e.g. the ceiling of a mine chamber) and by extending the second jack in a different direction so as to engage a different surface of a rock face or the like (e.g. the floor of a mine chamber) .

The second direction may be coaxial with the first direction. This permits the rotation of the excavator vehicle about this axis. It is preferred that the first jack is extendible away from an upper surface of the excavator vehicle.' In this case, it is preferred that the second jack is extendible away from a lower surface of the excavator vehicle.

It is preferred that the first jack is extendible in a generally upwards direction and the second jack is extendible in a generally downwards direction. The "upwards" and "downwards" directions refer to the directions when the excavator vehicle is placed in a substantially horizontal orientation .

The excavator vehicle may comprise a ground-contacting means for moving the excavator vehicle and a primary conveyor in spaced relationship from the means for moving the excavator vehicle, there being a part of the primary conveyor proximate to the means for moving the excavating vehicle, the excavator being provided with means for moving said part of the primary conveyor away from the means for moving the excavator vehicle.

It is preferred that the vehicle comprises a chassis and the jack arrangement is provided with a third jack for moving the chassis when the first and second jacks have secured the excavator vehicle. The third jack may be located in a space provided between the two primary conveyors. Those skilled in the art will realise that the third jack may move the whole of the vehicle but not the jacking arrangement. The conveyor, the means for excavating material, the apron (if present) and excavator main body (if present) may be associated with the chassis (for example, by being attached to the chassis) so as to be movable by the third jack. The chassis may be slidably movable by the jacking arrangement (typically slidably movable by the third jack) . This may be achieved by providing the vehicle with a slider arrangement, the slider arrangement comprising (i) slot for the receipt of a slider member and (ii) a slider member, the slot and slider ^smember being slidably movable relative to one another. The chassis may be provided with one of the slider member and the slot. The jacking arrangement may be provided with the other of the slider member or the slot. It is preferred that the chassis is provided with the slot and the jacking arrangement is provided with the slider member. It is preferred that the third jack is arranged to be extendible in a substantially forward direction. This facilitates the forward motion of the excavator and apron (if present) and facilitates the urging of an apron (if present) into positive engagement with the ground, thus permitting the apron to act as a shovel, excavating material from the floor.

The excavator vehicle may have a front and a rear, and may comprise a plurality of unloading positions, and a secondary conveyor arrangement arranged for the movement of excavated material to one or more of the plurality of unloading positions. One may therefore unload material to one or more unloading positions at any given time. For example, the excavator may be arranged to deliver excavated material to a first unloading position at one time. The secondary conveyor arrangement may then be reconfigured so as to unload excavated material to a second unloading position. This reconfiguring may take the form of moving one or more components of the secondary conveyor arrangement.

This allows excavated material to be delivered to different positions around the excavator vehicle, which may be desirable when working in enclosed spaces in which it is not always possible to position a collecting receptacle or collecting conveyor to the rear of the vehicle or to one side of the vehicle.

The secondary conveyor arrangement may be arranged so that when the second conveyor arrangement is in a first configuration, excavated material is deliverable to a first unloading position, and when the second conveyor arrangement is in a second configuration, excavated material is deliverable to a second unloading position. It is preferred that when the second conveyor arrangement is in a third configuration, excavated material is deliverable to a third unloading position. It is preferred that the secondary conveyor arrangement is readily interchangeable between the first, second and optionally the third configurations. In each of the first and second (and third, if present) configurations of the secondary conveyor arrangement, the secondary conveyor arrangement may be fixed in position relative to the remainder of the vehicle. Such interchangeability may conveniently be achieved by the second conveyor arrangement comprising a first secondary- conveyor. The first second conveyor may be a delivery conveyor for delivering excavated material onto a collecting conveyor or into a collecting receptacle. Those skilled in the art will realise that such a collecting conveyors and collecting receptacles are conventional and do not form part of the excavator of the present invention. A collecting conveyor is typically used to take excavated material away from the excavation site. The external conveyor is not part of the excavator of the present invention. The delivery conveyor may be an elongate conveyor. The delivery conveyor may typically have a first portion for receipt of excavated material and a second portion remote from the first portion. The second portion is typically raised compared to the first portion. This is to allow a collecting conveyor or receptacle to be placed below the delivery conveyor so that excavated material falling from the delivery conveyor is received by the collecting conveyor or receptacle. The excavated material may then be taken from the region from which it has been excavated.

In the first, second and optionally third configurations, the second portion of the delivery conveyor may be in mutually different positions. "Mutually different positio'ns" typically means in mutually different positions relative to the jacking arrangement.

In each of the first, second and optionally third configurations, the position of the second portion of the delivery conveyor may be fixed relative to the jacking arrangement. Thus, the position of the second portion relative to the jacking arrangement may be different in the first and second configurations, but in each of the first and second configurations, the position of the second portion (relative to the jacking arrangement) may be fixed.

It is preferred that the excavator comprises a first unloading position and a second unloading position. The first unloading position may be located on one lateral side of the excavator vehicle. The second unloading position may be located on another lateral side of the excavator vehicle. The secondary conveyor arrangement may be arranged for the movement of excavated material to both the first and second unloading positions.

The secondary conveyor arrangement may comprise two secondary conveyors. A first secondary conveyor may be arranged to transfer excavated material to the first unloading position and a ,second secondary conveyor may be arranged to transfer excavated material to the second unloading position. Thus, excavated material may be moved to the first and second unloading positions simultaneously.

The secondary conveyor arrangement may be located at or proximate to the rear of the vehicle. -Sl¬

it is preferred that the excavator vehicle is provided with a primary conveyor. for movement of excavated material to the secondary conveyor arrangement. The primary conveyor may have a first portion associated with the front of the excavator vehicle, and the primary conveyor may extend rearwardly, optionally from the front of the excavator vehicle .

The primary conveyor arrangement may be provided with two primary conveyors.

The excavator vehicle may be provided with a means for excavating material. The means for excavating material may be substantially as described with respect to the excavator vehicle of the first aspect of the present invention. ■^'

The excavator vehicle may be provided with an apron for the receipt of excavated material. The apron may^'be substantially as described with respect to the excavator vehicle of the first aspect of the present invention.

In accordance with a fourth aspect of the present invention, there is provided an excavator vehicle having a front and a rear, and comprising a plurality of unloading positions, and a secondary conveyor arrangement arranged for the movement of excavated material to one or more of the plurality of unloading positions. One may therefore unload material to one or more unloading positions at any given time. For example, the excavator may be arranged to deliver excavated material to a first unloading position at one time. The secondary conveyor arrangement may then be reconfigured so as to unload excavated material to a second unloading position. This reconfiguring may take the form of moving one or more components of the secondary conveyor arrangement.

Such interchangeability may conveniently be achieved by the second conveyor arrangement comprising a first secondary conveyor. The first second conveyor may be a delivery conveyor for delivering excavated material onto a collecting conveyor or into a collecting receptacle. Those skilled in the art will realise that such collecting conveyors and collecting receptacles are conventional and do not form part of the excavator of the present invention. A collecting conveyor is typically used to take excavated material away from the excavation site. The external conveyor is not part of the excavator of the present invention. The delivery conveyor may be an elongate conveyor. The delivery conveyor may typically have a first portion for receipt of excavated material and a second portion remote from the first portion. The second portion is typically raised compared to the first portion. This is to allow a collecting conveyor or receptacle to be placed below the delivery conveyor so that excavated material falling from the delivery conveyor is received by the collecting conveyor or receptacle. The excavated material may then be taken from the region from which it has been excavated.

In the first, second and optionally third configurations, the second portion of the delivery conveyor may be in mutually different positions. "Mutually different positions" typically means in mutually different positions relative to the front of the vehicle. "Mutually different positions" typically also means in mutually different positions relative to a primary conveyor, if such a primary conveyor is present.

In each of the first, second and optionally third configurations, the position of the second portion of the delivery conveyor may be fixed relative to front of the vehicle. Thus, the position of the second portion relative to the front of the vehicle may be different in the first and second configurations, but in each of the first and second configurations, the position of the second portion (relative to the front of the vehicle) may be fixed. In the first configuration, the second portion may be to one lateral side of the vehicle. In the second configuration, the second portion may be to a different lateral side of the vehicle or may be to the rear of the vehicle. It is preferred that in the second configuration, the second portion is to a different lateral side of the vehicle and in a third configuration, the second portion is to the rear of the vehicle.

This allows excavated material to be delivered to either side of the excavator vehicle, which may be desirable when working in enclosed spaces in which it is not always possible to position a collecting receptacle or collecting conveyor to the rear of the vehicle or to one side of the vehicle.

The secondary conveyor arrangement may comprise a first secondary conveyor, switchable between a first state in which said first secondary conveyor may transfer excavated material to ^'the first unloading position and a second state in which said secondary conveyor may transfer excavated material to the second unloading position. This is conveniently achieved by having a bidirectional conveyor. This may be achieved using a conveyor which is drivable in two directions (for example, by using a bidirectional motor or by using an idler gear to reverse the direction of travel of the conveyor) . It is therefore possible to deliver excavated material selectively to the first unloading position or the second unloading position.

Alternatively, the first and second secondary conveyors may each be switchable between a first state in which the first and second secondary conveyors may transfer material to the first unloading position and a second state in which -the first and second secondary conveyors may transfer material to the second unloading position.

The secondary conveyor arrangement may be located at or proximate to the rear of the vehicle. It is preferred that the excavator vehicle is provided with a primary conveyor for movement of excavated material to the secondary conveyor arrangement. The primary conveyor may have a first portion associated with the front of the excavator vehicle, and the primary conveyor may extend rearwardly, optionally from the front of the excavator vehicle .

The excavator vehicle may be provided with a means for excavating material. The means for excavating material may be substantially as described with respect to the excavator vehicle of the first aspect of the present invention.

The excavator vehicle may be provided with an apron for the receipt of excavated material. The apron may be substantially as described with respect to the excavator vehicle of the first aspect of the present invention.

An excavator in accordance with the present invention is now described by way of example only with reference to the following figures of which:

Figure 1 is a perspective view (generally from above) of an example of an embodiment of an excavator in accordance with the first, second, third and fourth aspects of the present invention;

Figure 2 is a perspective view (generally from below) of the excavator of Figure 1; Figure 3 is an exploded, simplified view of the jack arrangement used in the excavator of Figures 1 and 2; Figure 4a is a perspective view (generally from above) of a further example of an embodiment of an excavator in accordance with the present invention;

Figure 4b is a plan view from above of the excavator of Figure 4a;

Figure 4c is a side-on view of the excavator of Figure 4a; Figure 4d is a plan view from below of the excavator of Figure 4a;

Figure 4e is an first end-on view of the excavator of Figure ^' 4a, looking in the direction of arrow A and

Figure 4f is a second end-on view of the excavator of Figure 4a, looking in the direction of arrow B.

Figure 1 shows a perspective view of an example of an embodiment of an excavator in accordance with the first, second, third and fourth aspects of the present invention. The excavator is denoted generally by reference numeral 1 and comprises two primary conveyors 2a, 2b which extend from the front of the vehicle 1. The primary conveyors 2a, 2b are attached to an apron 23 for collecting excavated material, and, in use, excavated material is transferred from the apron to the primary conveyors. The excavator is provided with two cutters 9a, 9b, each of which is in the general form of a cylinder which is rotatable about its longitudinal axis and is provided with cutting teeth (two of which are labelled, 30a, 30b) on its exterior surface. The cutters 9a, 9b are mounted on an arm 8. The arm 8 is pivotally attached at pivot point 10 to a mounting point (not labelled) . The arm 8 may be pivoted about pivot point^' 10 so that cutters 9a, 9b may be brought into contact with the ground. Rotation of the cylindrical cutters 9a, 9b causes the cutting teeth to gouge away at the material to be excavated.

The arm 8 may enter the space between the two primary conveyors 2a, 2b if needed for operation of the arm 8.

The excavator vehicle 1 is further provided with caterpillar tracks 3, 33 which are driven by powered wheels 4, 5, 34, 35. Each of the primary conveyors 2a, 2b is mutually spaced from a respective caterpillar track 33, 3. Material may accumulate in the space between a primary conveyor and the respective caterpillar track. The excavator vehicle 1 is further provided with hydraulic rams for urging the primary conveyors 2a, 2b away from the respective caterpillar track 33, 3 by pivoting the primary conveyors about pivotal axis 11. This movement of the primary conveyors away from the respective caterpillar track increases the space between the conveyors and tracks, thus easing access for the purpose of cleaning.

The excavator vehicle further comprises a secondary conveyor arrangement 6. The secondary conveyor arrangement 6 comprises a secondary conveyor extending laterally across the width of the vehicle. The secondary conveyor is to the , rear of, and below, the primary conveyors 2a, 2b so that the secondary conveyor may receive excavated material from the primary conveyors 2a, 2b. The secondary conveyor is bidirectional i.e. may be driven in two directions. This means that the second conveyor may transfer excavated material to either side of the excavator vehicle. This means that a collecting receptacle or collecting conveyor may be placed on either side of the vehicle. Bidirectionality may be achieved in a number of ways, for example, by using a bidirectional motor or by providing an idler gear which, when engaged, reverses the direction of a conveyor belt. Further examples of bidirectional conveyors are disclosed in US4925016, US5318483 and US4095478.

Guard plates (not shown) are provided at each end of the secondary conveyor, but these guard plates have been omitted from the Figures in order to demonstrate more clearly the relationship between the primary conveyors 2a, 2b and the secondary conveyor arrangement 6.

The excavator vehicle is further provided with a jacking arrangement. The jacking arrangement comprises a first jack 7 which is extendible in a substantially upwards direction and a second jack 14 which is extendible in a substantially downwards direction. The "upwards" and "downwards" directions refer to the directions when the excavator vehicle is placed in a substantially horizontal orientation. The first 7 and second 14 jacks are provided with contact plates 13, 15 respectively for contacting an adjacent surface. Each contact plate is mounted to the respective jack by a suitable joint to allow movement of the contact plate to establish good contact between the contact plate and the surface. In use, the first 7 and second 14 jacks may be extended so that the contact plates 13, 15 engage with the ceiling and floor respectively of a chamber in which the excavator vehicle is operating. The second jack 14 provides sufficient force to support the weight of the excavator vehicle 1, and so the majority of the excavator vehicle

(apart from the jack/contact plate, of course) may be raised from the floor. This may be advantageous if it is desirable to clean the caterpillar tracks 3, 33. If the tracks 3, 33 are not in contact with the ground, then the tracks may be operated in an effort to remove any undesirable material from the tracks without moving the vehicle. The primary conveyors 2a, 2b may be moved away from the tracks 3, 33 as described above prior to operating the tracks for cleaning.

The contact plates may be urged into the respective surface with sufficient force so that a third jack 16 may be used to move the vehicle in a generally forward direction. The third jack 16 is mounted so that extension of the third jack 16 causes, inter alia, the primary conveyors 2a, 2b, apron 23, arm 8, cutters 9a, 9b and secondary conveyor 6 to move forward. This is advantageous when the excavator vehicle 1 is operating on a slope and/or in slippery conditions when it is not possible to move the vehicle forward using the caterpillar tracks. The apron may be urged into contact with the ground before extension of the third jack 16. In this way, the apron may act as a shovel which excavates material on forward motion of the apron.

The first, second and third jacks comprise hydraulic rams. Such hydraulic rams are known to those skilled in the art.

The excavator vehicle is provided with a power pack (not shown) . The power pack is electrically powered. The power pack is mounted in a first operational power pack position. The power pack is readily removable from the first operational power pack position by virtue of it being mounted onto the vehicle with readily removable bolts. The power pack comprises, in this case, an electric motor. The power pack may be moved away from the rest of the vehicle, being connected to the rest of the vehicle by conduits carrying hydraulic fluid and pressure from the remotely sited power pack to the rest of the vehicle. The power pack is provided with an electrical input socket for providing electricity to the electrical motor. The electric motor provides power to a hydraulic pump that is provided as part of the removable power pack. The hydraulic pump pumps hydraulic fluid from a hydraulic fluid tank to the hydraulically operated components of the vehicle. Quick release couplings are provided to enable conduits to be readily connected to, and disconnected from, the power pack. The quick release couplings are provided for both the "pressure" and "return" hydraulic circuits. Pressure relief valves are also provided in case the hydraulic pressure exceeds a predetermined value. Isolators are also provided for both the electric and hydraulic circuits.

The excavator vehicle does not have to comprise a removable power pack. The excavator vehicle may be electrically- powered (for example, battery powered as in US6199307).

The engine or motor for powering the excavator may, of course, be petrol or diesel-powered, as is well-known to those skilled in the art.

A simplified, exploded view of the jack arrangement used in the excavator vehicle of Figures 1 and 2 is shown in Figure 3. The jack arrangement is generally denoted by reference numeral 100, and comprises the upwardly-extending first jack 7 and the downwardly-extending second jack 14. The first 7 and second 14 jacks are secured in a metal block 40. One end of the third jack 16 is attached to attachment portion 43 which is secured to block 40. The other end of the third jack is attached to the front portion 60a of chassis 60. The block 40 is provided with two elongate guides (one of which is shown 41), one on either side of the block 40. Each guide is T-shaped in cross-section and comprises a narrow portion 42. The narrow portion 42 is located within receiving slots 44a, 44b formed in the rear portion 60b of the chassis 60. The chassis is movable relative to the guide 41. Operation of the jack arrangement 100 is now briefly described. Second jack 14 is extended downwards and the first jack 7 extended upwards so that the chassis 60 of the vehicle is raised from the ground and so that contact plates 13, 15 are firmly- engaged with a ceiling and floor respectively. Referring to Figures 1 and 2, the apron 23 may be moved into position to receive excavated material. Referring again to Figure 3, third jack 16 is extended, thus urging the front portion 60a and the rest of the chassis 60 forwards. The rear portion 60b of the chassis 60 may move relative to the guides 41 (and therefore the rest of the jack arrangement 100) because the guides 41 are received in respective receiving slot 44a, 44b.

The primary conveyors 2a, 2b, the second conveyor arrangement 6, the apron 23, arm 8 (with cutters 9a, 9b) and caterpillar tracks 3, 33 are all attached to the chassis 60 so that movement of the chassis causes movements of these components.

In a preferred embodiment (not shown in Fig. 3), the first jack 7 and the second jack 14 are co-axial. The first 7 and second 14 jacks may be extended so that the chassis 60 of the vehicle is raised from the ground and so that contact plates 13, 15 are firmly engaged with a ceiling and floor respectively. Because the first and second jacks are coaxial, it is possible, with care, to rotate the chassis 60 about the axis formed by the first and second jacks. This facilitates turning of the excavator vehicle without contact between the ground and the tracks; this reduces the damage caused to the floor by conventional turning operations.

Figures 4a-4f show a further example of an embodiment of an excavator in accordance with the present invention. The excavator is denoted generally by reference numeral 101 and comprises two primary conveyors 102a, 102b which extend from the front of the vehicle 101. The primary conveyors 102a, 102b are attached to an apron 123 for collecting excavated material, and, in use, excavated material is transferred from the apron to the primary conveyors. The excavator is provided with two cutters 109a, 109b, each of which is in the general form of a cylinder which is rotatable about its longitudinal axis and is provided with cutting teeth (two of which are labelled, 130a, 130b) on its exterior surface. The cutters 109a, 109b are mounted on an arm 108. The arm 108 is pivotally attached at pivot point 110 to a mounting point (not labelled) . The arm 108 may be pivoted about pivot point 110 so that cutters 109a, 109b may be brought into contact with the ground. Rotation of the cylindrical cutters 109a, 109b causes the cutting teeth to gouge away at the material to be excavated.

The arm 108 may enter the space between the two primary conveyors 102a, 102b if needed for operation of the arm 108. The excavator vehicle 101 is further provided with driven caterpillar tracks 103, 133. Each of the primary conveyors 102a, 102b is mutually spaced from a respective caterpillar track 133, 103. Material may accumulate in the space between a primary conveyor and the respective caterpillar track. The primary conveyors 102a, 102b may be pivoted about pivotal axis 111 to move the primary conveyor away from the respective caterpillar track 133, 103. This movement of the primary conveyors away from the respective caterpillar track increases the space between the conveyors and tracks, thus easing access for the purpose of cleaning.

The excavator vehicle further comprises a secondary conveyor arrangement 106. The secondary conveyor arrangement 106 comprises a lateral conveyor 106a and a delivery conveyor

106b. The lateral conveyor 106a extends laterally across the vehicle and is to the rear of, and below, the primary conveyor 102a so that the lateral conveyor 106a may receive excavated material from the primary conveyor 102a. The lateral conveyor 106a receives excavated material from primary conveyor 102a and delivers the excavated material to delivery conveyor 106b. Delivery conveyor 106b also receives excavated material from primary conveyor 102b. Delivery conveyor 106b has a raised end portion 106c so that a collecting conveyor or receptacle (not shown) may be placed below the end portion 106c so as to receive material from the delivery conveyor of the excavator.

Figures 4a-4f show the delivery conveyor 106b projecting rearwardly. The delivery conveyor may be arranged to extend laterally from either side of the vehicle as indicated by the dotted lines in Figure 4B. This is convenient when working in a cramped environment when the operator has little choice about the position of a collecting conveyor or receptacle to be used to take the excavated material away from the vehicle. Such an arrangement is also convenient when an excavator may move in a first direction along a face to cut material, and when the excavator moves in a second (opposite) direction along the face to cut material. It may^¬ be necessary to alter the relative position of the lateral conveyor 106a and the delivery conveyor 106b when changing the orientation^ of the delivery conveyor to ensure that excavated material from both primary conveyors 102a, 102b is moved to the delivery conveyor 106b.

The position and orientation of the delivery conveyor may be readily changed by the operator. In each different position or orientation of the delivery conveyor, it is attached to the rest of the vehicle, typically by metal pins.

The excavator vehicle is further provided with a jacking arrangement. The jacking arrangement comprises a first jack 107 which is extendible in a substantially upwards direction and a second jack 114 which is extendible in a substantially downwards direction. The "upwards" and "downwards" directions refer to the directions when the excavator vehicle is placed in a substantially horizontal orientation. The first 107 and second 114 jacks are provided with contact plates 113, 115 respectively for contacting an adjacent surface. The jacking arrangement operates in substantially the same manner as the jacking arrangement described above with reference to the excavator of Figures 1, 2 and 3. For example, the jacking arrangement operates as described above with reference to the excavator of Figures 1, 2 and 3 in order to move the chassis (not labelled) of the excavator and the other components of the vehicle associated with the chassis .

The excavator vehicle is powered with a power pack (not shown) . The power pack is typically located some distance from the rest of the vehicle, the power pack being connected to the rest of the vehicle by conduits carrying hydraulic fluid and pressure from the remotely sited power pack to the rest of the vehicle. The power pack is provided with an electrical input socket for providing electricity to the electrical motor. The electric motor provides power to a hydraulic pump that is provided as part of the removable power pack. The hydraulic pump pumps hydraulic fluid from a hydraulic fluid tank to the hydraulically operated components of the vehicle. Quick release couplings are provided to enable conduits to be readily connected to, and disconnected from, the power pack. The quick release couplings are provided for both the "pressure" and "return" hydraulic circuits. Pressure relief valves are also provided in case the hydraulic pressure exceeds a predetermined value. Isolators are also provided for both the electric and hydraulic circuits. An example of this type of power pack is the Celtic Miner 4500 power pack provided for the Celtic Miner 4500 vehicle (both available from Metal Innovations Holdings pic, Llandow, Cowbridge, South Wales, UK) .

Those skilled in the art will realize that the excavator vehicle does not have to comprise a removable power pack. The excavator vehicle may be electrically-powered (for example, battery powered as in US6199307). The engine or motor for powering the excavator may, of course, be petrol or diesel-powered, as is well-known to those skilled in the art.

The excavator of Figures 4a-4f is particularly adept at working in confined environments. The excavator 101 has a length of about 3.7m (including the 0.7m long "tail" provided by the delivery conveyor 106b), 1.2m wide and 0.8m high. Each of the cylindrical cutters 109a, 109b has a longitudinal length of about 0.5m and a diameter of 0.3m. Such a small machine is advantageous when seams of substrate are small or where it is not possible or disadvantageous to develop large galleries. Furthermore, the use of a small machine reduces the number and strength of supports which have to be used to support the walls and ceiling of a gallery. It has been found that the present excavator works very well in wet conditions on soft supporting ground where it would not be possible to use conventional larger excavators .

The cutters rotate at about lOOrpm, but this may be varied in order to achieve satisfactory cutting of a substrate; if the cutters rotate at too high or too low a speed, this may cause the cutting teeth 130a, 130b to "bounce" away from the substrate. Before the cutters may be rotated, the cutters are sprayed with water emanating from a spray nozzle (not shown) at a pressure of 100 pounds per square inch for a period of seven seconds. This spray disperses potentially flammable and toxic gases and helps suppress dust which is generated by the cutting process.

The cutting teeth 130a, 130b may be obtained from Sandvik Tools or Sandvik Mining and Construction LLC (Canada) .

Claims

1. An excavator vehicle having a front and a rear, the excavator comprising a means for excavating material and two primary conveyors for the movement of excavated material, each primary conveyor having a first portion associated with the front of the vehicle and each primary conveyor extending rearwardly, the excavator further comprising a jacking arrangement for securing the excavator vehicle, the jacking arrangement comprising a first jack extendible in a first direction and a second jack extendible in a second direction, different from the first direction.

2.An excavator according to claim 1 wherein the jacking arrangement is accommodated between the two primary conveyors .

3. An excavator vehicle according to claim 1 or claim 2 wherein the two primary conveyors are mutually spaced along substantially the whole length of the two primary conveyors .

4. An excavator according to any one preceding claim further provided with a. secondary conveyor arrangement, the two primary conveyors being arranged for the movement of excavated material to the secondary conveyor arrangement .

5.An excavator according to claim 4 wherein the excavator is provided with a plurality of unloading positions, the secondary conveyor arrangement being arranged for the movement of excavated material to one or more of the plurality of unloading positions.

6. An excavator according to claim 5 wherein the secondary conveyor arrangement is arranged so that when the second conveyor arrangement is in a first configuration, excavated material is deliverable to a first unloading position, and when the second conveyor arrangement is in a second configuration, excavated material is deliverable to a second unloading position.

7. An excavator according to claim 6, wherein ^'the secondary conveyor arrangement is readily interchangeable between the first and second configurations, and in each of the first and second configurations of the secondary conveyor arrangement, the secondary conveyor arrangement is fixed in position relative to the remainder of the vehicle.

8. An excavator according to any one of claims 4 to 7 wherein the secondary conveyor arrangement comprises a first secondary conveyor which is a delivery conveyor for delivering excavated material onto a collecting conveyor or into a collecting receptacle, the delivery conveyor having a first portion for receipt of excavated material and a second portion remote from the first portion, the second portion being raised compared to the first portion.

9. An excavator according to claim 8 wherein the secondary conveyor arrangement comprises a further secondary conveyor for moving excavated material to the delivery conveyor .

10. An excavator according to any one preceding claim comprising two ground-contacting means for moving the vehicle, each of the means for moving the excavator vehicle being associated with (and in spaced relationship with) a respective primary conveyor.

11. An excavator according to any one preceding claim wherein the second jack is extendible in a direction which is parallel and opposite to the direction in which the first jack is extendible.

12. An excavator according to any one preceding claim wherein the second jack is extendible in a direction which is coaxial with the direction in which the first jack is extendible.

13. An excavator according to any one preceding claim wherein the first jack is extendible away from an upper surface of the excavator vehicle and the second jack is extendible away from a lower surface of the excavator vehicle .

14. An excavator according to any one preceding claim wherein the excavator is provided with a chassis and the jack arrangement is provided with a third jack for moving the chassis when the first and second jacks have secured the excavator vehicle.

15. An excavator according to claim 14 wherein the chassis is slidably movable by the third jack, the third jack being arranged to be extendible in a substantially forward direction.

16. An excavator according to claim 15 wherein the excavator comprises a slider arrangement comprising (i) a slot for the receipt of a slider member and (ii) a slider member, the slot and slider member being slidably movable relative to one another, wherein the chassis is provided with one of the slider member and the slot and the jacking arrangement is provided with the other of the slider member or the slot.

17. An excavator according to claim 16 wherein the chassis is provided with the slot and the jacking arrangement is provided with the slider member.