The object of the invention is an apparatus for transfer¬ ring loose material such as peat, wood chips, coal, sand and the like from heaps or the like for further process¬ ing. In order to be able to perform the transfer, the apparatus is comprised of a conveyor, which preferably is a drag conveyor influencing the surface of the heap, such as a drag bar conveyor, for instance. Such a conveyor is designed to be raised and lowered vertically so that the conveyor is hinged at its discharge end in order to be turnable at least vertically. At the opposite end, the conveyor is suspended on a suitable raising and lowering device.

In order to extend the conveyor's area of operation, it is designed to be horizontally transferrable at least in respect to its end suspended on the raising and lowering device, whereby a sector equal to the horizontal dis- placement can be managed by the conveyor. Alternatively, the discharge end of the conveyor may be constructed to promote also a horizontal displacement in order to ex¬ tend the area managed by the conveyor. From the point of view of operation, it is advantageous also to have the discharge end of the conveyor vertically displaceable in order to be able to cope with different initial situ¬ ations considering the size and shape of the material heap.

Apparatuses of this kind are as such prior known and when using them the flow of material removed from the heap can be adjusted by lowering the conveyor in pace with the receding of the surface of the heap. The horizontal dis¬ placement of the conveyor is executed appropriately by having the heap removed essentially one horizontal slice at a time. The use of prior known control devices in these apparatuses leads to abundant idle operation, when the conveyor hangs on its lowering device too high with

respect to the surface of the heap. On the other hand the control device may lower the conveyor too rapidly with respect to the conveyor's discharge capacity and thereby cause overloading of the conveyor.

The apparatus according to the invention provides im¬ provements in regard to the shortcomings of prior known apparatuses so that the apparatus comprises a device which is connected to the suspension device, and controls the raising and lowering device by monitoring the suspen¬ sion load.

In accordance with a further characteristic of the inven¬ tion, it is possible to eliminate the groping associated with prior known apparatuses when being laterally dis¬ placed. In such situations, the prior known conveyors collide with the side of the heap too far up and operate at less than full capacity or if embedded too far into the heap they operate overloaded. This problem is elimin- ated by providing the apparatus with elements for moni¬ toring the vertical displacement of the suspending element while the conveyor is being laterally displaced. Another advantage of this further characteristic is that it accounts for changes caused on the heap from outside. An example of such a change is a supplementary load of material being added to the heap.

The invention is described in more detail by means of an equipment shown in the appended figures as one embodiment of the invention. In the drawings:

Figure 1 shows a side view of one recommended realis¬ ation of the apparatus in accordance with the inven¬ tion,

Figure 2 shows a part of apparatus seen from the sus¬ pended end of the conveyor and

Figure 3 shows a view from above of the apparatus shown in Figure 1.

Figure l is a schematic presentation of the basic realis¬ ation of the apparatus for the purpose of removing loose fuel material from a heap of the said material. The basic parts of the apparatus are the conveyor 1, attached from its discharge end to a pillar 6. This attachment is ex- ecuted in a hinged manner so that the conveyor 1 can be swung both vertically and horizontally. The conveyor 1 is attached to a raising and lowering device 3 by means of a suspending element 2 at the end opposite to its discharge end. The discharge end of the conveyor 1 shows a dis- charge conveyor 7 onto which the conveyor 1 surrenders the material removed from the heap of material. The said discharge conveyor can, for instance, convey the material to a combustion plant.

The raising and lowering device 3 is used to lower the pick-up end of the conveyor in pace with the receding of the surface of the heap as material is removed. A sensor 4 for recognising the suspension load imposed by the con¬ veyor l on the suspending element 2 is embodied in the set of equipment in accordance with the invention for the purpose of controlling the said lowering. The sensor 4 controls the raising and lowering device 3 so that the suspension load sensed by the sensor stays at the set value. The said control ensures that the conveyor 1 is lowered to conform with the surface of the heap so that the conveyor's transfer function is maximised, whereupon idle operation and overload situations are avoided.

As another control sensor, the apparatus includes a sen- sor 5 (Fig. 2) for monitoring the vertical displacement of the suspending element 2 which controls the func¬ tioning of the lateral displacement carriage of the

lowering and raising device 3. The purpose of the said sensor is to inform the control device of the horizontal displacement of the conveyor, and to prevent the conveyor from becoming disadvantageously positioned with respect to the side of the heap of material when the conveyor is displaced horizontally. In the event that the conveyor collides with the side of the heap of material at a point unsuitably low, the said collision will cause the sus¬ pending element 2 to be deflected from the vertical plane and this deflection is recognised by the sensor 5. The sensor 5 informs the control device of the occurrence whereupon the control device issues a command to the raising and lowering device 3 to raise the conveyor by a certain amount prior to proceeding to continuing with its horizontal displacement. If the conveyor still collides with the side of the heap, the aforementioned function is repeated until the sensor 5 no longer senses deflection from the vertical of the suspending element as lateral displacement proceeds. When this is the case, the control mechanism assumes the conveyor to have reached the top of the heap of material and commences the transfer function by lowering the conveyor guided by the information re¬ layed by the sensor 4 sensing the suspension load.

In the above situation, the heap of material may be transferred using the conveyor 1 by allowing the conveyor to come down a predefined distance after which it is raised slightly, displaced laterally a predefined step, lowered to the transfer position, allowed to come down while executing the transfer function, etc. However, the set of equipment in accordance with the invention also makes possible essentially linear proceeding at a speci¬ fic elevation thereby sweeping over the entire heap of material. When this is done, the starting point is the aforementioned top position and the conveyor sweeps away a slice of certain thickness per lateral displacement. In this function model, the sensor 4 sensing the suspension

load of the control element controls mainly the lateral displacement of the transfer carriage of the raising and lowering element 3 in such a manner that the load imposed on the sensor 4 stays at a certain value, monitored by the vertical deflection sensor 5. In accordance with these function models, and by way of an example, the ap¬ paratus is able to recognise supplementary loads added onto the heap of material since the preceding sweeping cycle and to control without any problems the conveyor also when it reaches point where the supplementary load was added.

The said basic set of equipment can, for instance, be operated within a certain sector finally delimited by the limit switches 8 of the transfer carriage of the raising and lowering device 3. The control logic for the set of equipment may also be thus construed that the movements of the conveyor serve to indicate when the edge of the heap of material has been reached and thereby avoid un- necessary lateral displacement of the conveyor.

In Figure 3, the set of equipment shown in Figure 1 is presented schematically as seen from above. In this ap¬ plication, the discharge end of the conveyor 1 is attached to the pillar 6 and the pick-up end is attached to the raising and lowering device 3 which in turn moves along a circular track with the pillar 6 as its centre.

The above basic apparatus can be supplemented by means of modifications such as those shown in the appended draw¬ ings. The hinged point of attachment to pillar 6 of the discharge end of the conveyor 1 can be achieved so that it can be moved vertically along the pillar 6. This fa¬ cilitates the advantageous positioning of the conveyor 1 in readiness for dealing with material heaps of varying sizes and shapes.

Further, the invention facilitates the mounting of the hinged point of attachment to pillar 6 of the discharge end of the conveyor 1 can be executed so that it can be moved laterally in which case the set of equipment can be operated covering a rectangular area of heaped material instead of a sector.

In the above, the invention is described as being appro¬ priate for the discharging of loose material from heaps, but the said equipment can also be applied for the oppo¬ site purpose, that of forming heaps of loose material.