Patent Description:
The maintenance and repair of a rotable bucket wheel assembly of a bucket wheel reclaimer are difficult and expensive exercises. In one method, this may involve the disassembly of component parts of the rotable bucket wheel assembly such as the bucket wheel itself, drive system, drive shaft, bearings, ring chute and discharge chute. While this disassembly occurs, and maintenance is being performed the bucket wheel reclaimer is unable to operate.

To speed up the maintenance process and thereby minimise downtime it has been proposed to construct a rotable bucket wheel assembly as an integral unit that can be disconnected from a bucket wheel reclaimer and moved as a unit to a maintenance location. While this is occurring a new or refurbished rotable bucket wheel assembly can be fitted to the reclaimer to enable normal operation.

<CIT> discloses a bucket wheel machine system and a method for maintenance of such a bucket wheel machine system.

<CIT> discloses a dual lane, multi-axle transport vehicle for moving heavy loads including a forward module mounted on a plurality of axles and a rearward module mounted on a plurality of axles.

The above references to the background art do not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art.

In one aspect there is disclosed rotable bucket wheel assembly for coupling to a boom of a bucket wheel reclaimer comprising:
a bucket wheel;.

In one embodiment the structural frame comprises a plurality of coupling points to enable coupling to a transfer system to facilitate transferring the load of the bucket wheel assembly from the boom to the transfer system whereby the bucket wheel assembly is capable of being transported away from the boom by the transfer system.

In one embodiment the coupling points are configured to facilitate coupling with the transfer system when the transfer system is disposed beneath the structural frame.

In one embodiment the structural frame is provided with a plurality of connecting mechanisms configured to cooperate with complementary connecting mechanisms on the boom, wherein when the structural frame is attached to the boom the connecting mechanisms on the frame engage the connecting mechanisms on the frame.

In one embodiment the connecting mechanisms comprise locating elements formed on the structural frame and arranged to cooperate with associated locating elements on the boom and wherein upon engagement of the locating elements remaining connecting mechanisms on the structural frame are in alignment with associated remaining connecting mechanisms on the boom.

In one embodiment the locating elements comprise hooks formed on the structural frame.

In one embodiment the locating elements comprise a plurality of pad eyes configured to receive coupling pins.

In one embodiment the rotable bucket assembly comprises a drive system mounted on the shaft.

In one embodiment the rotable bucket assembly comprises a conveyor pulley rotatably coupled to the structural frame.

In various embodiments the rotable bucket wheel assembly may also include any one or any combination of two or more of:.

The structural frame of the assembly forms a part of the boom of the bucket wheel reclaimer. Therefore, embodiments of the disclosed assembly can facilitate the maintenance of a rotable bucket wheel of a bucket wheel reclaimer by decoupling the structural frame from the remaining part of the boom and moving it to maintenance location. The bucket wheel assembly can be placed back into operation during the maintenance by attaching the structural frame of a like assembly to the boom.

In a second aspect there is disclosed a boom for a rotable bucket wheel reclaimer comprising:.

In a third aspect there is disclosed a method of refurbishing a bucket wheel reclaimer having a boom supporting a rotable bucket wheel assembly the method comprising:.

In on embodiment, moving the bucket wheel assembly comprises transferring the load of the bucket wheel assembly to a transfer system disposed beneath the structural frame.

In one embodiment the method comprises locating a transfer system beneath the structural frame and engaging the coupling points of the structural system with the transfer system wherein the transfer system carries the load of the bucket wheel assembly.

In one embodiment the method comprises disconnecting the connecting mechanisms of the structural frame from associated connecting mechanisms on the boom when the load of the bucket wheel assembly is transferred to the transfer system.

In one embodiment transferring the load of the bucket wheel assembly comprises operating a jack system on the transfer system.

In one embodiment the rotable bucket assembly comprises forming the transfer system as a transfer frame and a self-propelled modular trailer on which the transfer frame is demountable supported.

In one embodiment locating the transfer system comprises driving the self-propelled modular trailer on which the transfer frame is demountable supported to a position wherein the transfer frame is below the structural frame.

In one embodiment engaging the coupling points of the structural system with the transfer system comprises one or both of (a) operating the self-propelled modular trailer to lift the transfer frame into contact with the structural frame; and (b) operating a jack system on the transfer frame.

In one embodiment the method comprises forming the transfer system as a transfer frame on bogie mounted on a rail system.

In one embodiment locating the transfer system comprises driving the bogie on the rail system to a position wherein the transfer frame is below the structural frame.

Disclosed herein is a transfer system for facilitating the removal of a bucket wheel assembly from a boom of a bucket wheel reclaimer, the transfer system comprising a transport frame configured to support the bucket wheel assembly from a location beneath the bucket wheel assembly, and a jack system coupled with the transport frame and located on a portion of the transfer frame wherein the when operated the jack system is able to contact the bucket wheel assembly and transfer the load of the bucket wheel assembly to the transfer frame.

The transfer system may comprise: a trailer or self-propelled modular trailer or a rail mounted bogie on which the transfer frame is supported.

In various embodiments the rotable bucket wheel assembly may also include any one or any combination of:.

Notwithstanding any other forms which may fall within the scope of the apparatus and method as set forth in the Summary, specific embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:.

<FIG> shows a prior art bucket wheel reclaimer <NUM>. The reclaimer <NUM> has a boom <NUM> with a rotable bucket wheel <NUM> supported at a front end. The boom <NUM> is pivotally connected at an end opposite the bucket wheel <NUM> to a body structure <NUM>. A tower <NUM> extends upwardly from the body structure <NUM> and mechanically supports the front end of the boom <NUM>. The reclaimer <NUM> has rail wheels which run on as associate rail, and a switch room <NUM>.

<FIG> provide a close-up view of a front end portion of the boom <NUM> of the bucket wheel reclaimer <NUM>. The bucket wheel <NUM> is rotatably supported at the front end of the boom <NUM>. The bucket wheel <NUM> is shown with a plurality of attached buckets <NUM> and a ring chute <NUM>. Material picked up by the buckets <NUM> as the bucket wheel <NUM> rotates is dropped by gravity into the ring chute <NUM> and channelled onto and underlying conveyor <NUM>.

When the bucket wheel <NUM> is being maintained or repaired it may be decoupled from the boom <NUM> and lifted by a crane onto a transport vehicle, driven to a maintenance location, then lifted again by crane from the vehicle onto a purpose-built jig to facilitate maintenance and/or repair.

<FIG> depict an embodiment of the disclosed rotable bucket wheel assembly <NUM> (herein after also referred to as "bucket wheel assembly <NUM>" or "assembly <NUM>") coupled to a boom 12a of a bucket wheel reclaimer 10a. The bucket wheel assembly <NUM> includes a structural frame <NUM> that in use forms a structural part of the boom of a bucket wheel reclaimer. The structural frame <NUM> supports a bucket wheel <NUM> having a plurality of attached buckets <NUM>; a ring chute <NUM> and associated discharge chute <NUM>. The bucket wheel <NUM> is attached to the middle of shaft <NUM>, which is supported by two bearings (one shown as item <NUM>, the other being hidden under the bucket wheel discharge chute). The drive unit is attached to the shaft <NUM> to provide the rotation torque, and the drive unit is also attached to the structure <NUM>. The structural frame <NUM> couples to a portion of the reclaimer boom and transfers the load of the assembly <NUM> to the reclaimer boom when the reclaimer is in operation.

The bucket wheel assembly <NUM> may also include a plurality of rollers <NUM> in the form of conveyor belt idler support/troughing rollers. The rollers <NUM> are located adjacent the discharge chute <NUM>. When the bucket wheel assembly <NUM> is in use, the bucket wheel <NUM> rotates relative to the ring chute <NUM>/discharge chute <NUM>. Material picked up by the buckets <NUM> is held in the buckets by the ring chute <NUM> and is then dumped by gravity onto the discharge chute <NUM> onto a conveyor (not shown) that runs over the rollers <NUM>.

Also supported on the structural frame <NUM> forward of the rollers <NUM> is a boom conveyor pulley <NUM>. A reclaimer boom conveyor (not shown), which runs along the length of the boom, turns about the pulley <NUM>.

The structural frame <NUM> is provided with a plurality of coupling points <NUM> to facilitate connection to a machine to enable the rotable bucket wheel assembly <NUM> to be supported and lifted relative to the boom and then moved away from the reclaimer for example to a repair/maintenance location. The coupling points <NUM> are distributed about the structural frame <NUM> to ensure that the load of the rotable bucket wheel assembly <NUM> is substantially balanced when supported and lifted by the crane. The coupling points may be in the form of pinned coupling, hooked couplings or bolted couplings. The coupling points <NUM> in this embodiment are configured to facilitate coupling with a jacking mechanism or machine disposed beneath the structural frame <NUM>. In this instance the coupling points <NUM> also act as jacking points. Therefore, in this embodiment there is no need for a crane to lift the structural frame <NUM> and the bucket wheel assembly <NUM>, but rather a mechanism or machine beneath the bucket wheel assembly <NUM>.

The ability to swap out a bucket wheel assembly <NUM> without the use of a crane has advantages over know prior art methods. The assembly <NUM> may have a mass in the order of <NUM> tonnes or more. Therefore, a heavy lift crane would be required. Such cranes are very expensive to hire and due to their limited number not always available particularly if an off-cycle maintenance and repair is required. This is of course not to say that in other embodiments the coupling points <NUM> cannot be arranged to facilitate connection with a crane.

Looking more closely the structural frame <NUM> has:.

The mounting structure <NUM> includes a rectangular frame <NUM> and a number of connecting mechanisms for connecting the bucket wheel assembly <NUM> to the rest of the boom 12a of a corresponding bucket wheel reclaimer 10a. In this embodiment there are six connecting mechanisms although in other embodiments this number may vary. Also, three different types of connecting mechanisms are incorporated. A first type incorporates or comprises locating elements, in this embodiment in the form of hooks <NUM>, one at each of the upper corners of the rectangular frame <NUM>. The hooks <NUM> are configured to sit on and engage corresponding pins fixed to the distal end of the boom 12a.

A second type of connecting mechanism incorporated in this embodiment is a fish plate <NUM>. Three fish plates <NUM> are provided as part of the mounting structure <NUM>. One fish plate <NUM> is on an upper element of the rectangular frame <NUM> in line with and midway between the hooks <NUM>. One of each of the remaining two fish plates <NUM> are located at the lower corners of the rectangular frame <NUM>. These two fish plates are in orthogonal plane to the fish plate <NUM> on the upper element.

A third type of connecting mechanism in this embodiment is a shear key <NUM> (<FIG>). This is in alignment with and midway between the fish plates <NUM> at the lower corners of the rectangular frame <NUM>.

When coupled to the boom 12a the hooks <NUM> carry the vertical load of the assembly <NUM> and shear key <NUM> transmits lateral forces resulting from operation of the reclaimer 10a. The fish plates <NUM> are bolted to the front end of the boom 12a to demountably fix the assembly <NUM> to the boom 12a.

Additionally, during the reattachment of the assembly <NUM> the hooks <NUM> assists in aligning the bucket wheel assembly <NUM> and in particular the fish plates <NUM> to facilitate an operational connection to the boom 12a.

<FIG> show sequentially an embodiment of the disclosed method for replacing/refurbishing a bucket wheel assembly <NUM>.

To start the removal of the bucket wheel assembly <NUM>, the reclaimer 10a is driven to a location where a front end of the boom 12a can be lowered onto a tie down cradle <NUM>. As shortly explained the removal of the bucket wheel assembly <NUM> also uses a transfer system <NUM> which in this embodiment comprises the combination of transport frame <NUM> and jack system which is incorporated in a self-propelled modular trailer (SPMT) <NUM> illustrated in <FIG>. In general terms the transfer system <NUM> facilitates the removal of a bucket wheel assembly <NUM> from the boom 12a of a bucket wheel reclaimer 10a. The transfer system <NUM> comprises the transport frame <NUM> which is configured to support the bucket wheel assembly <NUM> from a location beneath the bucket wheel assembly <NUM>, and a jack system coupled with the transport frame <NUM>.

The jack system is operable to enable contact between the transfer system and the bucket wheel assembly <NUM>. Here the jack system is provided in or by the SPMT <NUM> which also is drivable to move or transfer the bucket wheel assembly <NUM> away from the boom 12a and the reclaimer 10a. But in other embodiments described later the jack system can be incorporated in the transfer frame <NUM> itself.

One possible procedure for the removal of the bucket wheel assembly <NUM> will now be described.

As a precursor to decoupling the bucket wheel assembly <NUM> from the boom 12a the transfer system <NUM> (i.e. the transport frame <NUM> loaded on the SPMT <NUM>) is driven close to the tie down cradle <NUM>. The reclaimer 10a is driven into a location where the boom 12a can be lowered onto the support cradle <NUM> such as shown in <FIG>. The boom 12a is luffed down and slewed to a designated slew angle ensuring access by the transport frame <NUM> and SPMT <NUM>.

A hold down rope may be slung about the boom connection and secured. Optionally additional jacking cylinders may be installed to jack against the boom 12a to positively arrest the position of the boom 12a prior to commencing decoupling of the bucket wheel assembly <NUM>.

<FIG> and <FIG> show sequentially the transfer system <NUM> being driven underneath the bucket wheel assembly <NUM> to the purposes of removing the bucket wheel assembly <NUM> from the boom 12a. <FIG> shows the transfer system <NUM>, constituted by the SPMT <NUM> on which the transport frame <NUM> is carried, being driven in alignment with and toward the bucket wheel assembly <NUM>.

<FIG> shows the SPMT <NUM> and the transport frame <NUM> (i.e. the transfer system <NUM>) beneath the bucket wheel assembly <NUM>. The jacking points <NUM> on the structural frame <NUM> are in alignment with but spaced from corresponding seats <NUM> on the underlying transport frame <NUM>.

With the boom 12a is supported on the support cradle <NUM> and arrested against uncontrolled movement:.

As an aside, the removal of the conveyor belt may be part of a planned conveyor belt change out.

The bucket wheel assembly <NUM> can now be jacked upwardly using the jack system of the SPMT <NUM> to lift the hooks <NUM> above the corresponding locating pins on the boom 12a. This is also shown in <FIG>. The bucket wheel assembly <NUM> is now totally free of the boom 12a and its load is fully supported by the transfer system <NUM>.

As shown in <FIG> the transfer system <NUM>/SPMT <NUM> can be driven to a maintenance location. During this process the SPMT <NUM> can be operated to lower the bucket wheel assembly <NUM> thereby lowering the centre of gravity and enhancing safety.

<FIG> shows a maintenance platform <NUM> and associated transport frame supports <NUM> at a maintenance location. The maintenance platform <NUM> includes stairs and walkways to enable easy access by maintenance staff to the bucket wheel assembly <NUM>. The SPMT <NUM> is driven so that shoulders <NUM> of the transport frame <NUM> are in alignment with the supports <NUM> as shown in <FIG>. The SPMT <NUM> is now lowered so that the shoulders <NUM> engage the supports <NUM>. The load of the transport frame <NUM> is now carried by the supports <NUM>, as depicted in <FIG>. The shoulders <NUM> can be bolted to the supports <NUM> prior to the SPMT <NUM> being further lowered and driven out from under the transport frame <NUM>, as shown in <FIG>.

The SPMT <NUM> is then driven to pick up a new or refurbished bucket wheel assembly <NUM>' for installation on the front end of the boom 12a, as shown in <FIG>. The new or refurbished bucket wheel assembly <NUM>' is supported on another transport frame <NUM> at a location near the support cradle <NUM> and elevated for example on supports similar to the supports <NUM> to enable the SPMT <NUM> to drive beneath the transport frame <NUM>.

The sequence for installation is in essence the reverse of that for the removal and in summary involves the following steps:.

<FIG> show a second embodiment of the rotable bucket wheel assembly <NUM> and associated method and equipment for swapping out an assembly <NUM> for a refurbished or new assembly <NUM>. In describing this embodiment, the same reference numbers will be used as for the use embodiment to denote the same or substantially same features.

The second embodiment is similar to the first embodiment in that both have a structural frame <NUM> which supports the bucket wheel <NUM> and connects onto the boom 12a; and utilise a transfer system <NUM> having a transfer frame <NUM> and SPMT <NUM> to support and move bucket wheel assemblies <NUM> to and from the boom 12a. There are however differences in the connecting mechanisms operating between the structural frame <NUM> and the boom 12a as well as differences in how the transfer system <NUM> and in particular the transfer frame <NUM> engages the structural frame <NUM>. Also, as explained in greater detail below in this embodiment an access platform <NUM> is utilised that supports the transfer frame <NUM> and provides multiple degrees of movement for adjusting the position of the bucket wheel assembly <NUM> which may greatly assist in the reconnection of the bucket wheel assembly <NUM> to the reclaimer.

The structural fame <NUM> supports the ring chute <NUM> and associated discharge chute50 which is coupled with the bucket wheel <NUM>, wheel shaft, bearings and drive unit as in the previous embodiment although not individually visible in these figures. The structural frame <NUM> has a mounting structure <NUM> that includes a rectangular frame <NUM> and a number of connecting mechanisms for connecting the bucket wheel assembly <NUM> to the boom 12a.

However instead of three different types and a total of six connecting mechanisms; the structural frame <NUM> of this embodiment has only two types and a total of four connecting mechanisms, as shown in <FIG>.

The first type of connecting mechanism is in the form of pins <NUM> that pass through respective pad eyes formed on the rectangular frame <NUM> at a location corresponding to the hooks <NUM> of the first embodiment. Each pad eye locates between corresponding pairs of lugs <NUM> formed at each upper corner of the front end of the boom 12a. Respective pins <NUM> can then be inserted to couple a pad eye and a corresponding pair of lugs <NUM>.

A second form of connecting mechanism used in this embodiment is a fish plate <NUM> like that described in relation to the first embodiment. However here only two fish plates are used, one of each lower corner of the rectangular frame <NUM>. The fish plates <NUM> have a large tolerance for misalignment. While the vertical position is restrained by the pins <NUM>, a vertical key is applied in the fish plates <NUM> to align the connection in horizontal direction.

<FIG> shows the general structure of the bucket wheel assembly <NUM> as well as the setup for removing and installing a bucket wheel assembly <NUM>. The bucket wheel assembly <NUM> is attached to a front end of the boom 12a, with the boom 12a located in its normal storm parking position and tied onto the support cradle <NUM>. The access platform <NUM> is adjacent the support cradle <NUM>. The transfer system <NUM> is also shown located underneath the bucket wheel assembly <NUM>.

<FIG> show the support cradle <NUM> used in this embodiment. The cradle <NUM> is designed to lock the boom 12a positively against vertical and horizontal movements and to take the significant uplift forces once the bucket wheel assembly <NUM> has been removed. The cradle <NUM> has a structure which includes a vertical mainframe <NUM> that is braced backwards.

Two hydraulic tie-down mechanisms <NUM> with integrated mechanical locking assemblies are installed on top of the cradle <NUM>. Packer plates <NUM> are inserted between boom 12a and cradle upper cross beam <NUM>, once the boom 12a has been lowered. The boom is 12a pinned to the tie down mechanism <NUM> and pulled against the packer plates <NUM> with controlled hydraulic pressure, then mechanically locked in position.

For lateral restraint of the boom 12a, two conventional hand operated spindle mechanisms <NUM> are installed each side of the cross beam <NUM> of the cradle <NUM>. Minor boom adjustment is possible within the backlash allowance of the slew gear. Access to the tie down cradle <NUM> is provided from the access platform <NUM>.

<FIG> illustrate an embodiment of the access platform <NUM>. The main purpose of the access platform <NUM> is to provide adequate access around the bucket wheel assembly <NUM> during routine maintenance activities and for the bucket wheel assembly replacement procedure so that all necessary work can be executed safely from dedicated walkways without the need of temporary access via EWP or scaffolding. The access platform <NUM> also supports the transport frame <NUM> loaded with the bucket wheel assembly <NUM> and accommodates horizontal forces resulting from the alignment of the transport frame, and wind loads.

The access platform <NUM> has two main horizontal beams <NUM> on either side of a central opening providing a parking space for the transfer system <NUM> (SPMT <NUM> and the transport frame <NUM>). When the transfer system <NUM> is located within the central opening the legs of the transport frame <NUM> are supported on the horizontal beams <NUM>. All horizontal total movements of the transport frame <NUM> are actuated and controlled via hydraulic cylinders that on the longitudinal main beams <NUM> and on a cross beam <NUM> at the back of the platform <NUM>. With this arrangement the bucket wheel assembly <NUM> can be aligned properly and effectively with the connection points of the boom 12a from the very course position attributed to the transfer system <NUM>/SPMT <NUM> travel, to a precise position enabling structural reconnection.

The rotable bucket wheel assembly <NUM> is adjustable in the horizontal plane by hydraulic cylinders mounted at each corner of the access platform <NUM> and a set of hydraulic cylinders mounted to the back cross beam <NUM>. The cylinders may be operated from ground level via portable power packs and with the assistance of spotters. For this purpose, the transport frame <NUM> rests on the longitudinal beams <NUM> and the SPMT <NUM> needs to be removed beforehand. Vertical adjustment of the bucket wheel assembly <NUM> is achieved via the jack system of the transfer frame <NUM>, which comprises four hydraulic cylinders located under the support pins between bucket wheel assembly <NUM> and cradle. The cylinders are operated in a <NUM>/<NUM> configuration which allows tilting about the longitudinal axis with the two independent back cylinders and tilting about the traverse axis with the two combined front cylinders. In one non-limiting example vertical adjustment may be in the order +<NUM> under load of the assembly <NUM>.

<FIG> shows an example of the transport frame <NUM> in this embodiment. The frame <NUM> is formed with legs <NUM> and shoulders <NUM>. The legs <NUM> enables the frame <NUM> to be placed on the ground while the shoulders <NUM> are configured to sit on the longitudinal beams <NUM>. In contrast to the first embodiment in this embodiment the jack system is provided as a part of the transport frame <NUM> and is embodied by four vertical lift and lock mechanisms <NUM>. The mechanisms <NUM> are at locations corresponding those of the seats <NUM> in the first embodiment for engaging the jacking points <NUM> of the structural frame <NUM>.

To enable easy access for the assembly <NUM> replacement, a front cross beam <NUM> of the transport frame <NUM> may have a bolted connection enabling removal during long term storage (but will need to be reinstalled for transport). The bucket wheel <NUM> with buckets <NUM> attached can be rotated when resting on the transport frame <NUM>.

<FIG> show the lift and lock mechanisms <NUM> and transport frame <NUM> coupled with the assembly <NUM>. and transport frame <NUM>. Each of the lock mechanisms includes a threaded and tapered pin <NUM> with hole clearance inside of a corresponding bracket <NUM>. Two nuts <NUM>, <NUM> are provided to lock (nut <NUM>) and to counter lock (nut <NUM>) the position. The bracket <NUM> provides sufficient clearance to support the pin <NUM> with a hydraulic jack <NUM> which is operable to extend and retract the pin <NUM> to adjust the vertical position of the assembly <NUM>. During transport and horizontal adjustment, the assembly <NUM> is locked with the four pins <NUM> to the transport frame <NUM>. The pins <NUM> are pushed into counter sections formed in the jacking points <NUM> of the structural frame <NUM>.

The change out of a rotable bucket wheel assembly <NUM> involves respective: parking; tiedown; removal and installation procedures. These are broadly described below.

Prior to the tie down procedure commencing, the transport frame <NUM> on the SPMT <NUM> (i.e. the transfer system <NUM>) is driven into the central opening of the platform <NUM>, then lower the SPMT to place the shoulders <NUM> on the longitudinal beams <NUM>.

The boom 12a is fully restrained against uplift and lateral movements. This involves in this embodiment the boom 12a being pulled down to the tie down cradle <NUM> and secured in vertical and lateral direction. With reference to <FIG> this can be achieved with the following procedure performed at both sides of the support cradle <NUM> simultaneously:.

The rotable bucket wheel assembly <NUM> is removed as follows:.

The installation of a new or refurbished assembly <NUM> is performed as follows:.

<FIG> show a third embodiment of the rotable bucket wheel assembly <NUM> and associated method and equipment for swapping out an assembly <NUM> for a refurbished or new assembly <NUM>. In describing this embodiment, the same reference numbers will be used as for the use embodiment to denote the same or substantially same features.

This embodiment is similar to the second embodiment shown in <FIG> in that it uses a transfer system <NUM> having a transport cradle <NUM> having a jack system comprised of four jacks to engage jacking points on the structural frame <NUM> of the rotable bucket wheel assembly <NUM>, and uses a pin connection at the top corners of the structural frame <NUM> adjacent the boom 12a and bolted connections at the bottom two corners, similar to the pins <NUM> and fish plate <NUM> shown in <FIG>.

With reference to <FIG> a substantive difference however lies in the motive aspect of the transfer system <NUM> for moving the assembly <NUM> supported on a transport cradle <NUM> of the transfer system <NUM> to facilitate the swapping out the worn assembly <NUM> for a new or refurbished assembly <NUM>. In this embodiment the transfer system <NUM> has rail mounted bogie system <NUM> rather than a SPMT <NUM> as in the first and second embodiments. The bogie system <NUM> supports a structure <NUM> that includes a transport frame <NUM> as well as an integrated work platform. The bogie system <NUM> enables the transfer system <NUM> and associated transport frame <NUM> to move along mutually orthogonal rail tracks <NUM>, <NUM>.

The bogie system <NUM> comprises: a first bogie system enabling movement of the transport frame <NUM> parallel to and in alignment with the boom 12a along the tracks <NUM> as shown by double headed arrow <NUM>; and a second bogie system enabling movement of the transport frame <NUM> transverse to the boom 12a along the tracks <NUM> as shown by double headed arrow <NUM>.

The bogie systems are equipped with drives to roll in and roll out the assembly <NUM>. Thus, during the shutdown of the reclaimer no additional manipulation equipment (such as a trailer, or SPMT) is needed which may cause additional down time as the cradle has to be moved also sideways.

When the transfer system <NUM> and supported assembly <NUM> is being moved along tracks <NUM> by the first bogie system, the second bogie system is disengaged. Conversely when the transfer system <NUM> and supported assembly <NUM> is being moved along the tracks <NUM> by the second bogie system, the first bogie system is disengaged. Engagement and disengagement of the bogie systems is achieved using hydraulics. The second bogie system is disengaged during travel along the tracks <NUM> and is activated with a hydraulic system once the transverse tracks <NUM> are reached. Fully engaged, the first bogie system is lifted/retracted and transverse movement along rail <NUM> is possible. The complete process mitigates potential risk by not needing any manual work in the vicinity of the cradle.

The rail mounted transfer system <NUM> can achieve minimal down time, accurate preadjustment and risk mitigation. The transfer system <NUM> with the new assembly <NUM>' can be located on the rails by trailer or SPMT prior to the shutdown because it is outside of the operation limit of the reclaimer. As mentioned previously, no interaction with other transport equipment during shut down is needed.

If the worn assembly <NUM> is to be transported to a different location for maintenance work a hydraulic trailer or SPMT <NUM> (<FIG>) can be placed underneath the frame <NUM> and the complete unit can be lifted and transported.

The procedure for changing out a bucket wheel assembly <NUM> using the transfer system <NUM> will now be described.

Prior the shutdown an empty transfer system <NUM> and a transfer system <NUM> with a refurbished bucket wheel assembly <NUM> are placed on top of the rail system by hydraulic trailer or SPMT in the maintenance area.

The bucket wheel reclaimer 10a is driven to a maintenance area and slewed to locking position at <NUM>° slew angle.

The boom 12a is lowered onto a support cradle (ground mounted ballast), with the boom 12a luffed to approximately -<NUM>°. The horizontal adjustment of the bucket wheel assembly <NUM> relative to the tracks may be done by spindles mounted on the storm tower.

The boom 12a is locked to the ground by either a manual or hydraulic mechanism mounted onto the ground mounted ballast structure. Then a degree of pretension between boom and ground mounted ballast is generated by bleeding off the luff cylinders of the reclaimer 10a. The pretension is required to have just minimal movement during the change out process between the boom 12a and the bucket wheel assembly <NUM>.

Embodiments of the disclosed rotable bucket wheel assembly <NUM> provide the genesis for a new form of boom for a reclaimer. The boom comprises the combination of a first structural portion and the structural frame <NUM> of the rotable bucket wheel assembly <NUM>. This combination provides the substantive structural and operational features of a boom of a conventional reclaimer but of course has the benefit that the bucket wheel assembly <NUM> which includes the structural frame <NUM> can be decoupled together with the remaining components of the rotable bucket wheel assembly <NUM> as a single unit.

An embodiment of the disclosed method for performing maintenance on and/or repairing a bucket wheel reclaimer includes an initial and prerequisite step of forming the boom of the reclaimer as a first structural portion and a demountable structural frame coupled to a front end of the first structural portion. In this method the structural frame includes the structural frame <NUM> of the rotable bucket wheel assembly <NUM>. The maintenance thereafter involves uncoupling the structural frame <NUM> from the front end of the boom; and lifting the bucket wheel assembly <NUM> by the structural frame <NUM>. This is achieved by attaching the structural frame <NUM> to a lifting machine via the lifting points <NUM>. The use of cranes can be avoided by lifting the assembly from below, using a jack system. The transfer system <NUM> can initially support the rotable bucket wheel assembly <NUM> during decoupling of the structural frame <NUM> from the remainder of the boom. Once the structural frame <NUM> is decoupled a vehicle can move or transport the bucket wheel assembly <NUM> which of course includes the structural frame <NUM> as a single unit to a maintenance location.

Claim 1:
A rotable bucket wheel assembly (<NUM>) for coupling to a boom (12a) of a bucket wheel reclaimer (10a) comprising:
a bucket wheel (<NUM>);
a shaft (<NUM>) coupled to the bucket wheel (<NUM>);
bearings (<NUM>) through which the shaft (<NUM>) extends; and characterized by
a structural frame (<NUM>) on which the bucket wheel (<NUM>) and shaft (<NUM>) are supported, wherein the structural frame (<NUM>) is arranged for demountable attachment to an end of a boom (12a) of a bucket wheel reclaimer (10a).