AU2003100532B4 - Improved road header - Google Patents

Description

P/00/009 Regulation 3.2

AUSTRALIA

Patents Act 1990 INNOVATION PATENT SPECIFICATION Invention Title: Applicant: IMPROVED ROAD HEADER JOHN HOLLAND PTY LTD The invention is described in the following statement: 2 IMPROVED ROAD HEADER The present invention relates to a road header machine for mining, mine development and civil tunnelling, and excavation of rock and in particular to an improvement in such a machine.

Road header machines are used for excavating rock surfaces, for creating openings or tunnels in the rock and the machines employ an excavating or cutting head, which is mounted for rotation on one end of a boom. The boom is mounted at the other end to a carriage, which provides the motive force and controlling mechanisms to drive the cutting head to rotate and the boom to move and which reacts the excavation loads transmitted through the cutting head and boom. The boom is mounted for movement both vertically and horizontally to allow the cutting head to sweep across the rock face and to excavate the face to create an opening or tunnel of any desired shape.

When excavating a tunnel, the walls and roof of the tunnel are supported progressively as excavation takes place, to stabilise the walls and roof of the tunnel against fragmentation or collapse. The tunnel walls and roof can be supported by a variety of different methods, and one common form of support is bolting. Bolts are installed manually or automatically, and in manual installation, the approach adopted for installation varies depending on the height of the tunnel being excavated. For a tunnel with only a low height, work personnel may be able to install the support in the roof and walls while standing on the tunnel floor, while in tunnels of greater height, it is normal for personnel to stand on a part of the carriage (a platform is sometimes provided). In either case, the object is to install the bolts into roof and wall sections behind or just back from the rock face being excavated. It is preferable for the bolts to be installed reasonably close to the rock face, to ensure that the tunnel walls and roof are stabilised as soon as possible after they are created.

Installing support, such as bolting in the above manner, usually is sufficient to stabilise the roof prior to fragmentation or collapse, although wall or roof sections can, albeit infrequently, fragment or collapse, which places the safety X:AKthylAndrewTrishlMPROVED ROAD HEADER.doc 3 of personnel, in particular those completing the support installation, at significant risk of injury or even death.

It is an object of the present invention to provide a road header machine which improves the safety of personnel, in particular those personnel involved in the installation of tunnel support.

A road header machine according to the invention is operable for excavating a tunnel through rock and includes a movable carriage, a boom extending from and mounted at one end to the carriage for sweeping movement through vertical and horizontal axes, a cutting head mounted to an opposite end of the boom for rotation, a roof guard mounted to the carriage and movable from a withdrawn position to an operative position. In the operative position, the guard is in contact with the roof of the excavated tunnel preferably adjacent the face under excavation to support the tunnel roof from fragmentation or collapse above or adjacent the roof guard, a stabilising arrangement being provided to stabilise the roof guard during movement to and at the operative position.

Employment of a roof guard in a road header according to the invention advantageously reduces or even eliminates the possibility of rock falling from an unsupported tunnel wall or roof and compromising the safety of personnel.

Accordingly, the safety of personnel can be increased, but with little or no change to the rate of tunnel excavation.

A roof guard as defined above can be fitted to existing road headers, or can be included in the construction of new road headers. In one arrangement, the roof guard is hydraulically shifted between the withdrawn and operative positions, although pneumatic operation, or mechanical operation, such as by pulley or cam arrangements, could be employed. However, hydraulic operation is considered preferable, given that typically other parts of a road header would be hydraulically operated, so that the hydraulic systems already exist in known road header construction.

In a preferred hydraulic arrangement, a pair of hydraulic rams may be mounted on opposite sides of the road header and hydraulic extension of the pistons of T.\TresselmPu .20300532.8pedAmend.0 02.04.doc the rams is employed to lift the roof guard from a lowered withdrawn position to a raised operative position. The movement can be vertical or inclined as appropriate. The hydraulic rams could be mounted elsewhere in relation to the road header, such as within the sides of the header, and the particular positioning adopted may depend on whether the roof guard is fitted to an existing road header, or a new road header which is designed to include a roof guard.

In an alternative arrangement, the rams may extend from and in engagement with the tunnel floor, so that any loading experienced by the rams is transmitted through the rams to the floor. The rams may be fixed to the road header, for example, so as to be movable with the road header when it is moved forward or backwards within the tunnel, but the arrangement can be such that when the roof guard is raised to the operative position, the rams are each supported for load bearing against the tunnel floor. For this, the rams may be fixed to the road header in a manner that raises the feet of the rams from the tunnel floor when the guard is shifted to the withdrawn position for movement of the road header, while the manner of fixing may return the feet of the rams into engagement with the tunnel floor automatically, when the roof guard is shifted to the operative position.

In an alternative arrangement, a single hydraulic ram may be employed, with suitable guides provided to guide the roof guard. The single ram may be centrally positioned with respect to the opposite sides of the road header and it may be arranged for attachment to the road header as appropriate. Likewise as discussed above, the ram may engage the tunnel floor in the operative position of the roof guard.

The roof guard is arranged for contact with the tunnel roof preferably under only very light pressure. This is because forcing the roof guard against the tunnel roof under high pressure serves no positive purpose. That is, while the tunnel maintains structural integrity against fragmentation or collapse, the application of a significant load against the roof of the tunnel does not add or improve that integrity. However, in the event that a section of the tunnel would otherwise X:ftathyndevATgisthMPROVED ROAD HEADERdoc fragment or collapse, the roof guard can support that section. In other words, the roof guard is operative upon the conditions for collapse or fragmentation occurring, to prevent such collapse or fragmentation. Under those conditions, the roof guard may experience significant loading and it is necessary that the structure of the roof guard and the structure provided to support the roof guard have sufficient strength to support the tunnel. With the tunnel supported by the roof guard, subsequent installation of support will stabilise the tunnel against collapse or fragmentation. Additionally, installing support in the tunnel section supported by the roof guard (which can include sections of the tunnel roof on either side of the guard) can be undertaken with personnel protected against fragmentation or collapse.

Advantageously, by using the roof guard, personnel who perform the support installation operation can position themselves below, or substantially below the guard, even though the tunnel section being supported is on either side of the guard, i.e. ahead or behind it, so that the roof section is "unguarded". By "unguarded", the reference is to a tunnel section which has not yet been supported and which does not have roof guard protection immediately below it.

Accordingly, by the invention, personnel can conduct the supporting operation from a guarded position, despite installing support in unguarded tunnel roof.

The roof guard preferably will have a generally planar facing surface for facing a generally flat tunnel roof. The roof guard alternatively will have a curved facing surface if the tunnel roof is curved. Therefore, the facing surface of the roof guard can be configured to suit the roof of the tunnel being excavated.

Preferably the guard extends fully across, or across a substantial portion of the tunnel. In particular, the extent of the roof guard should be such as provide protection for personnel who work beneath the guard, against rock fragmentation or collapse.

With the roof guard in position against or adjacent the tunnel roof, in one form of roof guard support such as, bolting takes place between a front edge of the guard and the tunnel face. The roof guard can be positioned, so that only a short unguarded rock span exists between the tunnel face and the roof guard, X:WKathyAndrwTrdshlIMPROVED ROAD HEADER.doc 6 with the span being sufficiently small that the likelihood of rock collapse or fragmentation is negligible. In a different form of roof guard, the guard can include openings or slots or the like, that facilitate bolting through the guard.

For example, a leading edge of the guard may be formed with a plurality of forward opening slots or fingers that facilitate bolting of the tunnel through the slots or spaces between the fingers, so that bolting can be conducted from below the guard.

The roof guard can have any suitable structure to provide the guarding function.

Mild steel is the preferred material for construction, although other materials could be employed as necessary to suit the environment under excavation.

While a generally planar rectangular shape is considered to be most appropriate, with support being provided at either end thereof, the guard may include any suitable strengthening or stiffening arrangement, and a suitable stabilising arrangement may also be provided. In one arrangement, the guard is movable between the withdrawn and operative positions by rams, preferably hydraulic rams, disposed at opposite ends of the guard. Because the guard can have a significant end to end dimension dependent on the size of the tunnel and the road header in a preferred arrangement, a stabilising arrangement is provided to engage the guard generally centrally between the ends thereof, to stabilise the guard against excessive vibration during movement and to maintain the guard against tilting or rotating in the event of tunnel collapse or fragmentation. In this respect, tilting of the guard may be possible depending on the type of connection made between the guard and the rams at either end.

While the connection preferably is a pin connection between each ram with a bracket extending from the bottom of the guard, such a pin connection may allow the guard to tilt or rotate about the pin connection when loaded by tunnel collapse or fragmentation. In this arrangement, a stabilisation arrangement can prevent such tilting or rotation.

In one arrangement, the stabilisation arrangement of the roof guard includes a bracket extending from the bottom surface of the guard and a stabilising arm extends from the bracket to a fixed point relative to the carriage. The stabilising arm can be pivot connected to each of the roof guard bracket and the -point of X:KathyAndrevTdshlIMPROVED ROAD HEADER.doc 7 fixing to the carriage and the effect of the arm under load is to prevent the roof guard from rotating about the pin connections of the guard with the rams.

More than a single stabilising arm can be employed, and in one arrangement, a pair of arms, spaced apart between the ends of the roof guard are provided. In a further arrangement, four arms are provided, two pairs of which are spaced between the ends of the roof guard, and in each pair the arms are spaced one above the other. The four arms define a three dimensional parallelogram and provide significant resistance to rotation or tilting of the roof guard under load and increase the load bearing capacity of the roof guard.

The connection of the stabilising arm or arms to the carriage can be to any suitable part of the carriage, but preferably the carriage is fitted with a bracket for pin connection with the or each stabilising arm.

In the above arrangement, as the roof guard is moved from the withdrawn to the operative position, connection to the stabilising arm or arms may cause the guard to slightly rotate. While this does not affect the end performance of the roof guard, preferably the length of the arm is sufficient that arc of movement of the arm is no more than about 500 and that rotation of the roof guard is minimised.

The attached drawings show an example embodiment of the invention of the foregoing kind. The particularity of those drawings and the associated description does not supersede the generality of the preceding broad description of the invention.

Figure 1 is a side schematic view of a road header machine according to one aspect of the invention.

Figure 2 is a top view of the road header machine of Figure 1.

Figure 3 is a front end view of the road header machine of Figure 1.

X:\KathyAndrewTdsh\lIMPROVED ROAD HEADER.doc 8 Referring to Figures 1 and 2, but in particular Figure 1, a road header machine is shown which includes a tracked carriage 11 having a caterpillar track 12, a rear foot support 13 and a front conveyor apron 14. An operator cabin 15 is supported on an upper and rearward section of the carriage 11, while a boom 16 extends from a forward end of the carriage 11, adjacent a rear portion of the conveyor apron 14. The boom 16 is shown in two positions, sweeping between a lower position 16a, through a vertical sweep to a raised position 16b. A cutting head 32 is fitted to the end of the boom 16 and is rotatable relative thereto. Figure 1 shows the cutting head 32 at the lower and raised positions 16a and 16b of the boom 16, and further shows an upper position of the cutting head 32 with the boom omitted.

Referring to Figure 2, the same road header machine 10 is shown, but that figure shows the rotational arc 17 of the boom 16 as it sweeps horizontally. A person skilled in the art would appreciate that the boom 16 is able to sweep simultaneously both vertically and horizontally, so that the boom has complete freedom of movement within the boundaries of its vertical and horizontal arcs to excavate an opening in a rock face of any suitable shape within those boundaries.

Attached to the carriage 11, on each side thereof, is a pair of hydraulic rams 18.

This is shown most clearly in Figure 3, and from that figure it can be seen that the hydraulic rams 18 are mounted generally in co-axial alignment, on elongate supports 19. The supports 19 are fixed in any suitable manner to the carriage 11, and suitable bolting and welding can be used for that purpose.

The hydraulic rams 18 are connected at the upper ends thereof, to a roof guard through a pin connection, and from Figure 3, that connection can be seen as comprising an inverted U channel 21 which receives an end portion 22 of a piston of the hydraulic ram 18 and through each of which extends a pin 23. It will be appreciated that by this pin connection, the roof guard 20 would be able to pivot about the pins 23 unless it is otherwise restrained. A suitable restraining mechanism is illustrated in the figures, and with reference to Figure 1, the mechanism comprises a bracket 24 which is centrally located on the X:KathyAndrewTrish\IMPROVED ROAD HEADER.doc 9 carriage 11, adjacent the operator cabin 15. The bracket 24 comprises a pair of spaced apart upright members 25 and a pair of diagonal cross-members 26 which brace the upright members 25. A further pair of bracing members 27 is shown in Figures 1 and 2, and those members provide a forward bracing capacity.

Extending from a bottom or underneath surface 28 (see Figure 3) of the roof guard 20, is a bracket 29 which comprises a pair of spaced apart fins 30 (only one of which is shown in Figure and which provide a connection point for connection between the bracket 24 and the roof guard 20 of a plurality of stabilizing bars 31. This arrangement is most clearly shown in Figure 1, although in that side view, only a pair of vertically spaced stabilizing bars 31 are shown, when in fact a further pair of bars spaced on the other side of the bars 31 shown, are provided. That further pair of bars is connected to the second of the fins 30 and to the adjacent of the upright members 25 not shown in Figure 1, and the arrangement of that pair of bars is identical to the bars 31 shown in Figure 1.

The roof guard 20 shown in Figures 1 and 3, is shown in a lowered or withdrawn position. In that position, it will be appreciated that the guard is positioned well below the roof of a tunnel which is excavated by the cutting head 32, and in the withdrawn position shown, the roof guard 20 provides no impediment to movement of the road header 10 along the caterpillar track 12.

By such movement, the cutting head 32 is brought into a position for engagement with the rock face of the tunnel and for commencement of excavation of that face. As tunnel excavation continues, the excavated tunnel is supported for stability, often by elongate rock bolts which are cemented or grouted into position. These rock bolts extend some distance into the tunnel walls or roof in the order of 500 mm or greater. Prior to bolting however, the tunnel is susceptible to collapse or fragmentation, and such collapse or fragmentation can have serious consequences for the safety of personnel.

The propensity for the tunnel roof to collapse or fragment increases as the distance of the unsupported roof section increases. Accordingly, it is necessary X:Kathy AndrewMTdshlIMPROVED ROAD HEADER.doc to support the tunnel at the earliest opportunity as that minimises the likelihood of collapse or fragmentation as well as increasing the safety under which personnel who complete the supporting process work. Guidelines provide that personnel cannot work away from the road header beneath unsupported tunnel sections. Personnel therefore install support at or immediately adjacent the road header. However, by employing the roof guard 20, personnel can work ahead of the road header, supporting the tunnel earlier against fragmentation or collapse than would be permitted without the roof guard. Therefore, by employment of the roof guard, personnel can safely install tunnel support ahead of the roof header at tunnel sections that are less prone to fragment or collapse, but guarded against such fragmentation or collapse in the event that it would have otherwise occurred.

With reference to Figure 1, operation of the road header will be clear. Figure 1 shows the cutting head 32 at a rearward position, identified by broken line R and an advanced forward position identified by the broken line F. These lines represent the vertical sweeping of the cutting head 32 on the boom 16, and shows the advance of the cutting head through subsequent sweeps from R to F.

It will be appreciated that in making a vertical sweep, horizontal sweeps of the kind shown in Figure 2 are also made to create the tunnel.

When the sweep R is completed, personnel move in to support the tunnel prior to the further excavation along sweep line F. In a road header 10 according to the present invention, when support installation takes place, the roof guard 20 is raised by the hydraulic rams 18, while being stabilised by the stabiliser bars 31, to a position either in light pressure engagement with the tunnel roof surface 34, or to a position close to but slightly spaced from that surface. In the event that the tunnel roof is likely to collapse or fragment, then the roof will be supported by the upper surface 35 of the roof guard 20 against that fragmentational collapse.

By use of a roof guard 20 according to the invention, personnel can alternatively complete the support process forward or rearward of the roof guard advantageously, personnel may shelter below the roof guard while performing X:\(athy~ndrewMTr1sh\1MPROVED ROAD HEADERdoc 11 the support operation thereby being shielded from rock that may drop from the tunnel roof, while the support process is completed. In particular, the roof guard may include a forward extending lip 36, that is slotted or includes openings, for passage for example, of a roof bolt therethrough and in that arrangement, the roof guard 20 may be brought into firm engagement with the roof surface 34 prior to bolting taking place.

When installation of the support is completed, the roof guard 20 may be withdrawn from the operative raised position by the hydraulic rams 18, for forward movement of the carriage 11 so that the excavation along sweep line F can be commenced. Once that sweep line has been completed, the roof guard may again be raised while the next support operation takes place.

The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the above description.

X:%KathyAndrewMTr1sh\IMPROVED ROAD HEADERdoc

Claims (4)

1. A road header machine including a movable carriage, a boom extending from and mounted at one end of the carriage for sweeping movement through vertical and horizontal axes, a cutting head mounted to an opposite end of the boom for rotation, a roof guard mounted to the carriage and movable from a withdrawn position to an operative position, in said operative position, said guard being positioned closely adjacent to, or in contact with the roof of the excavated tunnel to support the tunnel roof or walls from fragmentation or collapse above or adjacent the roof guard, a stabilising arrangement being provided to stabilise the roof guard during movement to and at the operative position.

2. A road header machine according to claim 1, said roof guard being movable substantially vertically between said withdrawn and operative positions.

3. A road header machine according to claim 1 or 2, said roof guard being generally rectangular in plan view and being in use, disposed to extend transverse across a tunnel being excavated and being supported at or adjacent opposite ends thereof on rams operable to move the roof guard between the withdrawn and operative positions.

4. A road header machine according to any one of claims 1 to 3, said stabilising arrangement including at least one stabilising arm which extends between and is pivotably connected at each end to said roof guard and said carriage, said arm extending rearwardly from said roof guard to the connection with said carriage and said arm pivoting through an arc of about 250 on either side of horizontal as said roof guard moves between said withdrawn and operative positions. 7 in ss.~Pmfl~iOOA32 SMdAmal.M 02*04*noc A road header machine according to claim 4, said stabilising arrangement including four arms, two pairs of which are spaced between opposite ends of said roof guard, and in each said pair, said arms are spaced substantially one above the other, said arms defining a three dimensional parallelogram. DATED: 6 February 2004 PHILLIPS ORMONDE FITZPATRICK Attorneys for: JOHN HOLLAND PTY LTD T:'Trens PBtUl23100532.SpedClAmnd 0.02.04.doc