GB2153876A - Tunnelling machine or roadheader with boom-mounted flipper arm - Google Patents

Abstract

A boom-type tunnelling machine having a shield or a boom-type roadheader machine having a gathering apron, is characterised in that a flipper arm 47 is mounted on the boom. Preferably the flipper arm comprises a scoop movable between a retracted position, in which it does not interfere with the normal operation of the tunnelling machine or roadheader, and an extended position, in which it is engageable with the tunnel or roadway floor adjacent the front edge of the shield or apron by movement of the boom, the scoop, when engaged with the floor, being movable so as to clear cut material from the floor onto the gathering apron. The flipper arm is used to clear debris accumulating in front of the shield or apron to enable the machine to be steered correctly. <IMAGE>

Description

SPECIFICATION Tunnelling machine or roadheader with boom-mounted flipper arm The present invention relates to a tunnelling machine or roadheader, and in particular to such a machine having a boom-mounted flipper arm.

Tunnelling machines are used in many civil engineering and mining projects to form tunnels, for instance for sewage, drainage, water transport, road and rail tunnels. They can also be used to form access tunnels to mineral sources.

Generally, the tunnelling machine comprises a shield which surrounds the remainder of the machine. The shield is generally cylindrical, although may have any desired cross sectional shape. The edge of the shield, which, in use, is located towards the end of the tunnel generally slopes towards the centre of the shield. A conveyor is located under the sloping edge of the shield inside the shield to remove material cut from the tunnel.

In a first type of tunnelling machine, a sledge is fixed inside the shield and a pedestal support is slidably mounted on the sledge. A sumping ram connects the pedestal support to the sledge so that the support can be moved to and fro on the sledge. In this type of machine the shield has on its periphery a number of advancing rams arranged to bear on tunnel lining sections as they are fixed in place behind the tunnelling machine as it advances.

In a second type of tunnelling machine, the support pedestal may be fixedly mounted within the shield and there are not sumping rams. To sump this type of machine, the advancing rams have to be used. A jacking station remote from the end of the tunnel is used to push all the installed tunnel sections up to the shield towards the tunnel end once the advancing rams have been retracted. Further tunnel sections are then added to the remote end of the tunnel. This method of forming a tunnel is generally known as pipe jacking.

In both types of machine, a boom is mounted on the support pedestal, generally on a turntable, and is rotatable in a horizontal plane. The boom is pivotable on the turntable in a vertical plane. In some cases the boom may also be extensible along its axis, although this is not common.

A cutting head is rotatably mounted at the end of the boom remote from the pedestal support. The cutting head may be cylindrical, but is generally of truncated conical shape.

On the outside surface of the cutting head are mounted a plurality of cutting picks, usually in a scroll formation. A plurality of sumping picks may also be provided on the face of the head remote from the boom.

A guide ring for ensuring that the correct tunnel profile is formed maybe mounted on the boom for engagement with a guiding surface mounted on the shield. In some cases, the guiding surface comprises the sloping front edge of the shield.

The cutting head is rotatable by means of a powerful motor, usually mounted in the boom. The motor may be electrically or hydraulically powered. The pivoting of the boom and the rotation of the turntable may be achieved by use of electric motors, but generally is achieved by use of hydraulic rams.

In use, the cutting head is caused to rotate and the head is sumped into the end of the tunnel. In the first type of machine, this is done by using the sumping rams to move the support pedestal towards the tunnel end on the sledge. In the second type of machine, this is done by the advancing rams pushing the whole of the machine and the shield towards the tunnel end.

Once the head is sumped in, the boom is rotated and pivoted and where possible, extended and retracted, so that the cutting head is moved along a desired path, for instance a circular path, to cut out material from the end of the tunnel.

The material cut from the tunnel falls onto the tunnel floor. Before the machine is advanced to enable it to further cut out the tunnel, it is desirable to remove the cut material. One way of doing this is manually.

However, in these tunnelling machines there is very little space and it is therefore difficult for an operative to get to the floor on which the material is lying. Moreover. it is dangerous for the operative, as the roof above him will be unsupported and the boom may inadvertently be moved. The operative could therefore be injured by material falling from the roof or by the boom.

Therefore it has been proposed that a backhoe arrangement should be provided in the shield which can be operated to scrape the material from the floor onto the conveyor.

However, this is not possible in most tunnelling machines as there is no space available for such an arrangement. Even if there is space available, it may be necessary to provide the arrangement on a slide to enable it to be retracted when the boom is being rotated and pivoted. If such an arrangement is provided it must be used in a separate operation, thus adding to the time needed to excavate a tunnel.

Another proposal for removing the material has been to use the cutting head as a backhoe arrangement. In this method of operation, the boom is lowered as far as it can go, and then retracted, either by use of the sum ping rams or by its extending and retracting mechanism. If no such mechanism is available, as may be the case in a pipe jacking operation this method cannot be used. More over it is not a desirable procedure in that it puts undesirable strains on the machine, and especially on the picks. It is also not particularly efficient and may not entirely clear the material.

Therefore, in general, clearance of the material is achieved solely by the advance of the shield, the sloping front edge of the advance of the shield, the sloping front edge of which forces at least part of the material towards the conveyor.

However, it has not proved possible adequately to remove all the cut material before or during the advance of the shield. This can therefore cause problems in excavating tunnels using these machines. If relatively hard material is left in front of the shield, it can cause the orientation of the shield to change, thereby causing the tunnel to be driven in the wrong direction. Moreover, the boom or the guide may come into contact with unremoved material, making it difficult or impossible for the boom to be pivoted downwards to the extent required to cut out the correct tunnel profile. This can cause further problems because, as the shield is advanced, it will come into contact with unexcavated material. If this is relatively weak, the sloping edge of the shield may be able to cut through it, but only if a great deal of power is supplied to the advancing rams or jacking station.If the sloping edge cannot cut through the unexcavated material, the shield may be damaged or may be moved out of alignment. In extreme cases, sections of the tunnel may be shattered by the compression forces acting on it.

A simiiar type of machine, usually known as a roadheader, is often used in mining operation, for instance to drive roadways alongside mineral seams or to excavate minerals from a seam. In roadheaders the pedestal support is mounted on a tracked vehicle and the cutting head is sumped in by moving the machine on the vehicle, rather than by use of advancing rams or jacking stations. The roadheaders are generally only provided with a roof shield.

The tracked vehicle may also include stelling jacks and feet to hold the roadheader in position once it has been sumped in. The boom is then pivoted and rotated as with a tunnelling machine to cut out a desired profile.

The problem of removal of cut material also exists with such roadheaders. There were therefore developed boom-type roadheaders having a gathering apron disposed below the boom for engagement with the roadway or seam floor. In one alternative, the apron is provided with central conveyor running paral lel to the roadway direction and at least one pivotable gathering arm or star wheel on either side of the conveyor. Pivotal movement of the arms towards the conveyor or rotation of the star wheels causes the gathering of material accumulating on the apron and its movement to the conveyor for transport out of the roadway. Thus, as the roadheader is advanced into the roadway, cut material is forced onto the apron, and removed by the gathering arms or star wheels and conveyor.

In a second alternative, the apron is provided with a conveyor extending around its periphery, and especially extending along the front edge of the apron, which extends across the floor of the roadway. As the roadheader is advanced into the roadway, the cut material is forced onto the conveyor for transport out of the roadway.

It has been observed that in general boomtype roadheaders having a gathering apron can work efficiently without any need for an operator to move into the area beneath the unsupported roof area Most of the cut material is removed efficiently from the roadway and the roadheader can be advanced into the roadway without difficulty.

However, it has also been observed that there are still some problems with the use of such road-headers. Although most of the cut material is removed by the gathering arms, discrete piles of it tend to accumulate on the roadway floor in front of the apron as the roadheader is advanced.

These piles cannot be cleared effectively by the gathering apron and can therefore interfere with the operation of the roadheader. In particular. it may become extremely difficult to pivot the boom in the vertical or horizontal planes to the extent necessary to enable the bottom corners of the roadway to be cut.

Also, the cut material in the pile may cause the apron, at least at its edges, to rise up, thus preventing the apron from operating at its greatest efficiency. Thus, these piles prevent continuous and smooth advance of the roadheader on a smooth floor.

Therefore in the case of both tunnelling machines and roadheaders, it is still necessary, at least periodically, to manually remove accumulated cut material from below the boom. For the reasons given above, this is a difficult and potentially dangerous operation.

It is an object of the present invention to provide a solution to the above problem by eliminating the need for manual removal of accumulated piles of cut material.

According to the present invention, there is provided a boom-type tunnelling machine hav ing a shield, or a boom-type roadheader hav ing a gathering apron, having a flipper arm mounted on the boom.

Preferably, the flipper arm comprises a scoop movable between a retracted position, in which it does not interfere with the normal operation of the tunnelling machine or road header, and an extended position, in which it is engageabie with the tunnel or roadway floor adjacent the front edge of the shield or apron by movement of the boom, the scoop, when engaged with the floor, being movable so as to clear cut material from the floor onto the gathering apron.

The scoop may have on its free end removable wear pads, so that its working life can be extended without having to dismount the whole assembly. The free end of the scoop may have on it teeth to improve its scraping action.

In a preferred embodiment, the scoop is pivotally mounted on the underside of the boom and, in its retracted position, lies with its longitudinal axis substantially parallel to that of the boom and, in its extended position, lies with its longitudinal axis at an angle to the axis of the boom. Advantageously, the scoop is pivotable through an angle of at least 90 , preferably about 1 35', between its extended and retracted positions. In its retracted position the scoop is conveniently located closely adjacent the the body of the boom. In this embodiment, the length of the scoop is such that in its extended position the free end of the scoop engages the floor before the cutting head reaches the lower end of its vertical pivotal movement.

Preferably, in this embodiment, the scoop is pivoted by means of a hydraulic ram or rams, conveniently connected thereto by suitable link arms and pivot points. Alternatively, the scoop could be pivoted by means of a reversible electric motor.

In this embodiment, the movement of the scoop to effect clearance of the cut material may be achieved merely by moving the scoop from its extended to its retracted position.

However, this movement may also be coordinated, either manually or automatically, with movement of the boom in the vertical plane to ensure that the free end of the scoop remains engaged with the floor for as much of its length of travel as possible, whereby cut material is efficiently cleared onto the shield or apron. This may also be achieved by allowing the boom to move freely so that the only forces acting on it are its own weight and forces generated by the movement of the scoop.

In alternative embodiments of the invention, the scoop may be moved between its extended and retracted positions by one mechanism and then moved while fixed in its extended position to effect clearance of cut material by another mechanism. For instance, if the boom is extensible, the scoop may be moved into its extended position and held there while clearance of cut material is effected by suitable pivotable movement and retraction of the boom. Alternatively, the scoop may be moved between its extended and retracted positions by one set of hydraulic rams, and moved while in its extended position by another set.

The operation of the flipper arm may be carried out automatically or manually and is preferably co-ordinated with the cutting operation of the tunnelling machine or roadheader.

For instance, if the operations are automatically controlled, the tunnelling machine or roadheader may be arranged such that the scoop is operated to clear any accumulated cut material each time the machine is advanced, whether or not sufficient material has accumulated to affect the machine's operation.

Alternatively, an operator may manually activate the flipper arm to clear cut material only when sufficient material has accumulated to affect the machine's operation. This alternative is useful if material accumulates in an usual position. The operator can then adjust the horizontal position of the boom to enable this material to be cleared.

It will be evident that both manual and automatic co-ordination of the cutting and scraping operations could usefully be provided, with the manual operation being used to over-ride the automatic operation in unusal circumstances.

It will be appreciated that, even if coordination of cutting and scraping operations is carried out manually, it is still possible for co-ordination of boom and scoop movement during the scraping operation to be carried out automatically.

It is envisaged that the flipper arm may be fitted to any of the boom-type tunnelling machines having a shield or boom-type roadheaders with a gathering apron currently available.

The present invention has the advantage over previously used tunnelling machines or roadheaders that it can clear piles of cut material accumulating in front of the shield or gathering apron without the need for men to go into the hazardous and generally confined space below the boom. Moreover, the clearance of the piles may be carried out automatically. The present invention therefore facilitates the continuous smooth advance of a tunnelling machine in a clean excavation or of a roadheader on a clean floor, enabling the advance to be carried out automatically, and much more safely.

It is envisaged that a tunnelling machine of the present invention will be of particular use in civil engineering projects for forming lined under-ground tunnels for sewers, water courses, roads and railways. However, machines or road headers according to the present invention will also be of use in many other tunnelling operations and in the mining industry, as will be clear to a person skilled in the art.

One embodiment of a tunnelling machine according to the present invention is described hereinafter, by way of example only, with reference to the accompanying drawing, which shows a schematic side view of the tunnelling machine with its boom at the lower end of its vertical movement; Referring now to the drawing, the machine comprises a pedestal support 1 which is slidably mounted on a sledge 3. The pedestal support 1 is connected to the sledge 3 by sumping jacks (the end 5 of which is shown in the drawing) for moving the pedestal support 1 to and fro on the sledge 3.

The sledge 3 is fixedly mounted in a cylindrical shield 7, which has a sloping front edge 9. Advancing jacks 11 are mounted around the shield 7 for abutment with an adjacent tunnel lining section 1 3. The space between installed tunnel lining section 1 3 is filled with, for instance, concrete or a hardwood lining.

A turntable 1 7, which is rotatable in a horizontal plane, is mounted on the pedestal support 1, and a pair of boom pivoting hydraulic rams 1 9 (only one shown) are pivotally mounted on the turntable 17. An operator cab (not shown), including a seat and a control console is located at the rear of the machine.

Generally a power pack (not shown) for supplying electrical and/or hydraulic power is detachably connected to the rear of the tunnelling machine.

A boom 21 is mounted on a lifting arm 23 which is in turn mounted for pivotal movement in a vertical plane on the turntable 1 7.

The vertical position of the boom 21 is controlled by boom pivoting ram (the end 25 of which is shown in the drawing) which acts between the turntable 1 7 and the lifting arm 23.

A transfer conveyor 27 for transferring cut material, pushed thereonto from the sloping front edge 9 of the shield 7, to the rear of the machine is also provided.

The boom 21 includes an electric motor 29, having a fireproof connection 31, a gearbox 33 and a coupling 35 which drive shaft 37. A cutting head 39 is bolted onto the free end of the shaft 37. The cutting head 39 is shown schematically as a truncated conical member. This will have on it a plurality of cutting and sumping picks which are not shown.

It can be seen from the drawing that if any cut material accumulates behind the cutting head 39 but not on the sloping front edge 9 of the shield 7, it may prevent the boom 21 moving to the lower-most end of its travel.

This will, in turn, prevent the cutting head 39 from reaching the bottom of the tunnel. Also, if the material accumulates at the edges of the tunnel, the boom 21 may be prevented from reaching the tunnel edges. In this case, the machine will be unable to cut out the lower areas of the tunnel.

In order to avoid this problem, a flipper arm comprising hydraulic rams 41, link arms 43, 45 and scoop 47 is mounted on the boom 21. The scoop 47 is generally flat, but is curved at its edge and adjacent the link arm 43 so that, in the position shown in full in the drawing, it is located close to but slightly spaced from boom 21. This position is the scoop's retracted position. The construction of the flipper arm is symmethrical on either side of the boom and is as follows.

A mounting plate 49 is fixedly attached to the rear end of the housing for the motor 29.

The cylinder of hydraulic ram 41 is pivotally connected by plates 51 to the mounting plate so that the ram 41 can pivot in a vertical plane. (All other pivotal connections in the flipper arm mentioned below have their pivotal axes parallel to that of this connection.

The free end of the piston rod of ram 41 is pivotally connected to one end of first link arm 43. This link arm 21 comprises a pair of spaced plates having the piston rod received between them. A lug projecting from one edge of the scoop 47 is pivotally connected in a similar manner to the other end of link arm 43.

One end of second link arm 45 is pivotally connected to the first link arm 43 intermediate the other two connections, but adjacent the piston rod connection. The other end of the second link arm 45 is pivotally connected to a mounting block (not shown) which is fixed, for instance by welding, to the lower side of the front end of the housing for the coupling 35.

The scoop 47 is also pivotally connected to the mounting block, at a position somewhat in front of and below the connection for the second link arm 45, by means of a second lug on its edge.

The position shown in full lines in the drawing is the retracted position of the scoop 47. It can be seen that in this position, the scoop 47 cannot interfere with the normal operation of the machine.

However, if the piston rod of the ram 41 is retracted, it will cause the second link arm 45 to pivot about its mounting on the block. This will also cause the first link arm 43 to move, pulling with it the first lug on the scoop 47.

This will cause the scoop 47 to pivot about its mounting on the block. At the end of the retraction of the piston rod, the scoop 47 will occupy the position partly shown in phantom on the drawing. This is its extended position.

Clearly, moving the piston rod out of the cylinder again will cause the scoop 47 to return to its retracted position.

In use of the machine, the scoop 47 is normally held in its retracted position. The shield 7 is advanced towards the end of the tunnel by activating the advancing jacks 11 to bear against the tunnel section 1 3. The advancing jacks 11 are then retracted and the space created between the shield 7 and the tunnel section 1 3 is filled with a further tunnel section.

The cutting head 39 is sumped into the face by use of the sumping jacks, causing the pedestal support 1 to move towards the face on the sledge 3. The boom 21 is then pivoted in the horizontal and vertical directions, generally to cause it to follow a circular path, to cut out a further length of tunnel. The boom 21 is then moved away from the face by activating the sumping rams in the reverse direction.

The cut material accumulates on the tunnel floor. Once a length has been cut out, the process is repeated.

As the machine is advanced, most of the cut material may be pushed onto the sloping front edge 9 of the shield 7 and thence onto the transfer conveyor 27. However, some of the material will be pushed into piles generally underneath the boom 21.

In order to avoid the formation of these piles, it is preferred that the flipper arm is used before the machine is advanced. To do this boom 21 is lifted and the scoop 47 is moved to its extended position. The boom is then lowered until the bottom edge of the scoop engages the floor or the top of the pile of material. The scoop 47 is then moved to its retracted position. As the scoop moves, the pile of material is cleared onto the sloping front edge 9 or transfer conveyor 27 and transported out of the tunnel. The scoop 47 may be repeatedly moved between its retracted and extended positions to ensure that all the accumulated material is cleared.

Alternatively, when the scoop 47 of the flipper arm is in its extended position, it may be moved towards the vertical pivot point of the boom on the pedestal by means of a telescopic trunk, or by pulling the whole of the flipper arm assembly backwards by means of another set of hydraulic cylinders or motors, or by using the sumping jacks in a reverse direction, to clear the pile of material onto the conveyor.

The operation of the flipper arm may be automatic and co-ordinated with movement of the boom to enable the scoop to remain engaged with the roadway floor as much as possible. The horizontal position at which the flipper arm operates may be selected automatically, for instance at each edge of the roadway, or manually by the operator as he sees a pile forming.

In this way the continuous automatic formation of a tunnel with the machine advancing through a clean excavation can be achieved.

Claims (11)

1. A boom-type tunnelling machine having a shield or a boom-type roadheader machine having a gathering apron, characterised in that a flipper arm is mounted on the boom.

2. The machine of claim 1, wherein the flipper arm comprises a scoop movable between a retracted position, in which it does not interfere with the normal operation of the tunnelling machine or roadheader, and an extended position, in which it is engageable with the tunnel or roadway floor adjacent the front edge of the shield or apron by movement of the boom, the scoop, when engaged with the floor, being movable so as to clear cut material from the floor onto the gathering apron.

3. The machine of claim 2, wherein the scoop has on its free end removable wear pads, so that its working life can be extended without having to dismount the whole assembly.

4. The machine of claim 2 or claim 3, wherein the free end of the scoop has on it teeth to improve its scraping action.

5. The machine of any one of claims 2 to 4, wherein the scoop is pivotally mounted on the underside of the boom and, in its retracted position, lies with its longitudinal axis substantially parallel to that of the boom and, in its extended position, lies with its longitudinal axis at an angle to the axis of the boom.

6. The machine of claim 5, wherein the scoop is pivotable through an angle of at least 90 between its extended and retracted positions.

7. The machine of claim 5 or claim 6, wherein in its retracted position the scoop is located closely adjacent the body of the boom.

8. The machine of any one of claims 5 to 7, wherein the length of the scoop is such that in its extended position the free end of the scoop engages the floor before the cutting head reaches the lower end of its vertical pivotal movement.

9. The machine of any one of claims 5 to 8, wherein the scoop is pivoted by means of a hydraulic ram or rams, connected thereto by suitable link arms and pivot points.

10. The machine of any one of claims 2 to 4 wherein the scoop is moved between its extended and retracted positions by one mechanism and then moved while fixed in its extended position to effect clearance of cut material by another mechanism.

11. The machine of any one of claims 1 to 10, wherein the operation of the flipper arm is co-ordinated with the cutting operation of the machine.

1 2. A boom-type tunnelling machine having a shield, substantially as hereinbefore described with reference to the accompanying drawings.