AU4487499A - Milling drum module for surface miner - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: MAN TAKRAF Fordertechnik GmbH Actual Inventor(s): Gerhard Nies Dieter Hoffmann Volkmar Schrader Thomas Stenzel S^ Manfred John Klaus Potenberg Hans-Joachim Schombel Bernd Glockner Matthias Gnilke Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: MILLING DRUM MODULE FOR SURFACE MINER Our Ref 596306 POF Code: 249595/249595 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- Description The invention concerns a milling drum module for a surface mining machine, comprising a milling drum for the loosening of the material from the block to be excavated, a carrier frame to fasten the milling drum on the surface mining machine and a discharge chute to maintain the intermediate transport of the loosened material in the region of the milling drum and for the targeted transfer of the material on to the following discharge belt according to the generic part of the main claim. With the milling drum module cutting heights in the order of up to half of the diameter of the milling drum can be achieved. The invention can be used for surface mining machines with milling drums operating in the downcut manner, i.e. on the side of the block to be excavated the direction of rotation of the milling drum is from top to bottom.

In the case of surface mining machines with milling drums of the above mentioned type working in the downcut manner the material is loosened by cutting tools from the ground at a certain cutting depth over the entire width, is carried away in the direction of rotation, the material loosened on the outside is conveyed in the direction of the centre of the machine by helical guide elements and then thrown on to a discharge belt which is narrower than the width of the milling drum. The losses between the obtaining of the material and the S intermediate transport should be as little as possible. The 36 feed movement is produced by the travel of the machine in the direction of excavation. When compared with milling drums operating in the upcut manner, surface mining machines with ~milling drums operating in the downcut manner have the advantage that only a limited amount of dust is generated and 5 no large lumps are loosened from the ground or picked up and carried away laterally. At the same time the maximum achievable cutting depth depends from the diameter of the drum as well as the mountings of the milling drum and their arrangement on the surface mining machine.

Known surface mining machines of the above mentioned type have such a construction, that the drum-shaped mining organ engages the material to be removed up to one third of its diameter.

This limited cutting height is due to the fact that certain sub-assemblies of the mining organ, like the mounting of the milling drum and its drives and the drive transmission elements like, for example, chains and sprockets, are arranged on both sides next to the body of the drum and thus a collision may take place with the lateral layers (blocks to be excavated) not yet removed. Such engagement conditions of the drum-shaped mining organs relative to the material to be excavated are known in the case of a first group of surface miners, like the ones disclosed in DE 35 04 610 C2 and DE 36 42 809 C2. On this occasion the milling drums have the same diameter over their entire length. The mounting of the milling drums is carried out on both sides by shaft bearings.

So that the material could travel from the milling drum to the narrower removal belt, firstly cutting tools and continuous guide plates are provided on the milling drum along helices extending from the outside towards the inside, and secondly a E chute is provided in the direction of the material transfer before the discharge belt for the purpose of transversely conveying the material loosened in the outer regions in the direction of the central region, determined by the discharge S belt, and then correct its flight trajectory in the direction 3 of the removal belt. This flight trajectory changes with the rotational speed of the milling drum.

A second known group of surface mining machines having principally the same drive is disclosed in the pamphlet "Easi- 15 Miner Model 1224, Continuous Surface Miner" by the Huron company, USA and the USA patents 4,536,037 and 4,690,461. The body of the milling drum has the same diameter over its entire length. There are cutting tools and guide plates provided on helices on the circumference of the milling drum. By guiding the material from the outer regions towards the central region an increasing material movement can be noticed from the outside towards the centre. However, as the milling drum has the same diameter over its entire length, the load in the space between the shell of the milling drum and the cutting circle diameter diminishes towards the outside. This is a disadvantage because in the case of smaller drum diameters with principally the same wall thickness a smaller stability is achieved and for the purpose of achieving a space in the centre of the milling drum which is sufficiently large to accommodate and forward the material conveyed, the cutting tools have to be correspondingly long to achieve a sufficiently large cutting circle diameter.

The milling drum is mounted on both sides. The drive is transmitted via a chain drive to the milling drum on one side from the outside by a motor arranged above. To enable a reliable transfer of the material from the milling drum to the discharge belt, here too a chute with a wide entry opening is provided, which chute becomes narrower in the direction of the discharge belt and thus corrects the flight trajectory of the material in the direction of the removal belt in the case of deviations. The flight trajectory of the material changes with the rotational speed of the milling drum in this case also.

*°o*oo Both above referenced types of machines have been designed preferably for hard material, which is picked up by the machine following the milling operation and is loaded on to trucks travelling with it. With machines constructed in this manner for excavating deposits using the surface mining method after reaching the maximum cutting depth an increase of the mining capacity is achieved by increasing the feed rate of the machine. With this the disadvantages of an increased wear of the travelling gear and increased energy requirement, occurring as the result of a faster movement of the entire mining 35 machine, are taken into consideration. Furthermore, at these high travelling speeds the connection of the mining machine to a belt conveyor for the purpose of a continuous mining is possible only with difficulties. When surface mining machines of this type are used for the mining of material at greater cutting depths, means have to be provided to prevent a lateral moving away of the loosened material from the central region to the outside of the milling drum.

From the Canadian patent 2,015,719 a further surface mining machine with a milling drum constructed as a drum-shaped mining organ is known, which can operate with a cutting depth which is approximately half of the diameter of the mining organ. Since the mountings for the milling drum are situated inside the body of the milling drum, this cutting height may be slightly increased while optimising the drives provided on the outside at both sides of the milling drum. The provision of the drives next to the milling drum requires, however, special measures to protect it from mechanical impairments. The milling drum operates in the upcut manner. The material cut is carried away to the upper region of the milling drum, where from, due its gravity, it falls into the interior through the grille-shaped shell of the drum. In the interior a transverse conveyor is provided with a chute, from which the material is removed laterally to the outside by a transverse conveyor and transferred to a conveyor belt further removing it. To have adequate room for this, it is a prerequisite that on this side of the material discharge the block to be excavated had already S been removed. For this reason a specific mining technique is S" always connected with a machine of this type.

To ensure that the loosened material would reliably fall into the interior through the grille-shaped shell of the drum, a Smaximum number of revolutions must not be exceeded.

Furthermore, moist and clayey grounds have a negative influence on the maximum possible conveying capacity of the machine.

.o A surface mining machine which is similar to that described above, is further known from the Canadian patent application 2,169,048. The material, which has fallen through the grille construction of the body of the milling drum in the same manner as described in the above solutions, is removed by a transverse conveyor from the interior of the milling drum, transferred to a vertical screw conveyor which assumes the function of an intermediate conveyor, and further transported to a discharge belt. To provide the screw conveyor with an adequate freedom of movement in the region of mining during the feed movement, at the bottom end of the screw conveyor an additional milling drum with a vertical axis of rotation is provided. Thus the maximum cutting height of the main milling drum is limited by the cutting height of the additionally required smaller milling drum.

The previous statement is valid with regard to the limited conveying capacity and the disadvantageous affect of moist and clayey grounds.

In the German journal "Braunkohle", 1990, Vol.3, pp.28-34, under Item 4, a surface mining machine is described, wherein a drum-shaped mining organ working in the upcut manner comprising four bucket wheels provided on a common shaft, which is provided in front of the machine in the direction of travel.

Their fastening on the machine is carried out by two carrier arms, each of which is arranged between the outside and central bucket wheels. By accommodating the drives in the interior of the bucket wheels and by positioning the leads for these drives 3 in the free space together with the carrier arms between two adjacent bucket wheels, the necessary freedom of movement is achieved on the side of the mining organ. A mining organ constructed in this manner is more material intensive and S- consequently heavier than those described above. However, with 3; the mining organ cutting heights can be achieved which are greater than half the diameter of the mining organ. The upcut manner of operation of the mining organ, however, results in tearing of lumps which cannot be picked up by the machine as well as in generating dust. The material loosened in the Soutside regions of the pick-up organ is partly moved away to S"the outside and it forms piles over the entire length next to the mining section. To prevent the penetration of the loosened material through the intermediate spaces into the interior of the mining organ and thus disadvantageously influencing the mining process and/or the additional wear of moving parts, special technical precautions are taken to hold back the conveyed material. The carrier arms between the bucket wheels do not allow a transverse conveying of the material towards the centre in the region of the mining organ. For this reason an additional transverse conveyor is required behind the drum.

The object of the invention therefore is so to construct the milling drum module that it would be sufficiently stable and suitable for a robust use of the surface mining machine with high conveying capacities. For this purpose the milling drum is brought into engagement with the material to be removed over its entire cutting width with a cutting height of the magnitude of up to half of the cutting circle diameter and thus carrying out the excavating work without the drive elements colliding laterally with the cutting edge. During the picking up of the material and its further transporting from the milling drum to the discharge belt, favourable dynamic conditions should be present and as little as possible material losses should occur under different conditions of cutting depths, rotational speed of the milling drum, feed rate of the machine and material properties.

This objective is achieved with the construction and S" arrangement of the milling drum on the surface mining machine and the use of a discharge chute in accordance with the characterising features of the main claim. Two drives are provided symmetrically on both sides of the milling drum directly in its interior and fastened with its stationary part on the carrier frame on the one hand and coaxially with its rotating part with the flanges of the shell of the milling drum on the other. The mounting between the stationary and the rotating drive parts are so stable that they serve at the same time as the mounting for the milling drum. To enable to realise various rotational speeds, the motors of the drives are provided with transmissions. The discharge chute is arranged between the milling drum and the removal belt following in the conveying direction to enable a reliable transport of the material in the region of the milling drum and the transfer of the material on to the discharge belt under various operating conditions and material properties.

Advantageous refinements of the individual sub-assemblies of the invention are the subject matter of the sub-claims. To provide sufficient room for the drives in the interior of the milling drum and sufficient transport space on the outside between the cutting circle diameter of the cutting tools and the shell of the milling drum for the increasing passing through of loosened material occurring as the result of the transverse transport from the two outside regions towards the central region, the diameter of the central region of the shell of the milling drum is smaller than that of the two outside regions. Both transitions between the different diameters of the shell of the milling drum are inclined. Due to this a basic body is produced which can be technologically easily produced, is very stable and in the pick-up and transport regions for the material to be conveyed is well suited for the actual passing through of the conveyed material.

For the fastening of the milling drum on the surface mining machine a carrier frame is provided. It comprises a horizontal central carrier joined to the superstructure of the surface mining machine and a lateral carrier each provided on the right and left sides. The lower, free ends of the two lateral carriers have an annular construction and as mountings of the stationary flanges of the drives can be joined with them by A bolts. At the same time the lateral carriers are so angled at the bottom that they protrude from the outside laterally into the body of the milling drum. This protrusion takes place in the upper region, so that blocks up to a height corresponding to half of the cutting circle diameter of the milling drum can be excavated. The leads for the drives are guided from the S" drive container within a protected profiled section of the carrier frame. By virtue of the bilateral mounting and drive of the milling drum favourable prerequisites are created for the construction and the static and dynamic conditions. The clearly organised arrangement of the drives allows a simple maintenance and repair. The encased construction of the drives offers a high degree of protection from dust and external mechanical influences. On each side of the milling drum the inside mounting of the drive is used simultaneously for the mounting of the milling drum. The joining of the milling drum with the surface mining machine via the carrier frame represents a simple solution for freely accessible installation points.

Thus controllable hydraulic motors, electric motors or other motors with transmissions can be used as drives, having a compact construction. The only condition is that the drive shaft of each drive is arranged in the axis of the milling drum and is joined with the milling drum via suitable machine elements.

The fitting of the milling drum with cutting tools and guide plates is carried out as a function of the intended capacity parameters and the prevailing conditions of application. Thus the milling drum is made to suit the size of the lumps and the physical parameters of the material to be excavated, like hardness, brittleness, stickiness and others. At the same time it has to be ensured that the lumps of the loosened material are smaller than the available annular transport space of the milling drum, which space is limited inside by the shell of the milling drum and on the outside by the cutting circle diameter, as otherwise interruptions may occur in the material flow and, consequently, in the mining process.

So that material loosened in the outside regions, in particular by the free cutting cutters, could not fall out laterally from the annular transport space of the milling drum, end rings, made up from segments, are provided on both external edges and 3 35 end ring segments in the edge region of the discharge chute.

Due to the downcut cutting direction of the milling drum an excessive breaking up of the lumps and an annoying dust formation will be prevented.

Further details and advantages of the subject matter of the invention become apparent from the following description and the associated drawings, in which a preferred embodiment is illustrated with the necessary details. They show in: Fig.l a perspective illustration of a surface mining machine with a milling drum working in the downcut manner, Fig.2 a longitudinal section of the milling drum, Fig.3 a perspective, partly sectioned illustration of the milling drum with the special construction of the carrier frame in this region, Fig.4 a perspective illustration of the milling drum, oooo *oo o .25 ooo* o oo oo ooo oooo ooooo oooo Fig.5 the development of the shell of the milling drum showing the arrangement of the cutting tools and the guides for the conveyed material, Fig.6 the sub-assemblies of the milling drum, discharge chute and discharge belt in a perspective view, Fig.7 a perspective view of the discharge chute with the following discharge belt, Fig.8 a lateral illustration of the milling drum with the partly illustrated discharge chute, sectioned, and Fig.9 a partly sectioned illustration of the detail on the side of the milling drum and discharge chute, in top view.

The surface mining machine according to Fig.l comprises the main sub-assemblies of the undercarriage 1 with the travelling gear 2, the superstructure 3 and the drive container 4 provided on it as well as the driver's cabin 5 positioned on it.

Furthermore, in the direction of excavation before the travelling gear 2 there is the milling drum module 3, comprising the milling drum 7 with the drives 8, the carrier frame 9 and the discharge chute 10. The discharge belt 11 is directed inclined upwards through the superstructure so that it transports away from the milling drum 7. Following the discharge belt 11 in the direction of conveying the pivotable loading boom 12 is arranged on the rear end of the superstructure 3. The milling drum 7 operates in the downcut manner and is fastened at both sides on the carrier frame 8.

The feed movement is produced by the travel of the machine in the direction of excavation. The milling drum 7 with its cutting tools 72 is directed towards the block to be mined. The material is loosened from the block to be mined over the entire width of the milling drum 7, carried away in the direction of rotation while transported in the direction of the centre of the machine by means of guide elements to be described in the following, while conveyed in the region outside of the block to be mined by means of the discharge chute 10 and purposefully transferred onto the discharge belt 11. From the discharge belt 11 the material is transported to the pivotable loading boom 12 and transferred either intermittently to trucks or continuously, via a belt cart, on to a belt system.

According to Fig.2 the milling drum is fastened on the 9 superstructure 3 via the carrier frame 9. The carrier frame 9 comprises a horizontal central carrier 91 and a lateral carrier 92 and 93 each at the right and left which are angled twice.

S Each of the two lateral carriers 92 and 93 is bolted together with the central carrier 91 in a vertical joint 94 and respectively, and centralised. The basic body of the milling drum 7 is the shell 71 of the milling drum. It has a tubular construction and comprises a wide central tube 71a having a defined diameter D. and two narrower outside tubes 71b and 71c provided left and right from it and having a larger diameter

D

2 At both ends of the central tube 71a a flange 71f and 71g is fitted to both faces. Between the outside edge of each of the flanges 71f and 71g and the two outside tubes 71b and 71c bevelled transitions 71d and 71e are provided in the form of the envelope of a truncated cone. These components 71a to 71g of the shell 71 of the milling drum are welded together and thus form a stable basic construction.

The basic concept of the milling drum 7 provides a bilateral, symmetrical arrangement of the mountings and of the drives 8 and thus a favourable force flow divided evenly to both sides.

It is further provided that the mountings of the drive 8 between the stationary and the rotating drive parts are at the same time the mountings for the milling drum 7. The drives 8 are mounted in the longitudinal axis, which is also the axis of rotation 13, of the milling drum 7 centrally in the shell 71 of the milling drum in those regions which have the larger diameter D 2 Both drives 8 have an encased construction and each of them has a hydraulic motor 81 and a transmission unit 82.

On its fixed side the drive 8 has a first flange 82a and on the side of its drive shaft a second flange 82b. The two flanges S 82a of the stationary part of the drive are joined to the carrier frame 9 leading to the superstructure 3. For this purpose the two free ends of the lateral carriers 92 and 93 are S also provided with flanges 96. The external shape of the lateral carriers 92 and 93 in the region of the shell 71 of the milling drum is so constructed that without hindering the rotating movement they protrude on both sides laterally from above into the shell 71 of the milling drum. The special S annular construction of the two lateral carriers 92 and 93 of the carrier frame 9, which protrude laterally into the shell 71 of the milling drum, is illustrated in Fig.3.

The stationary, non-rotating flanges 82a of the two drives 8 are bolted together with the respective flange 96 and 97 of the carrier frame 9 as are the flanges 82b of the output shaft with the flanges 71f and 71g associated with the shell 71 of the milling drum. Thus the drives 8 of the milling drum abut with their flanges 82b against the flanges 71f and 71g of the milling drum 7 and large portions of their transmission units 82 protrude through the flange 71f and 71g into the interior of the central tube 71a of the shell 71 of the milling drum. Due to the fact that the outside diameter of both flanges 71f and 71g is greater than the outside diameter D, of the central tube 71a, the drives 8 can be bolted together with the milling drum 7 from the outside without presenting any hindrance to the fitter. Thus a quick and problem-free fastening and detaching of both drives 8 is feasible. The entire mounting and dismantling of the drives 8 is also facilitated by that both lateral carriers 92 and 93 of the carrier frame 9 can be unbolted from the horizontal central carrier 91. For this purpose a joint 94 and 95 each with centring is provided between the two lateral carriers 92 and 93 and the horizontal central carrier 91. So that the lateral carriers 92 and 93 could be pulled off the central carrier 91 in a simple manner when being dismantled, guide tubes 91a and 91b are provided which in the region of both lateral carriers 92 and 93 protrude into the central carrier 91, which guide tubes are surrounded by sliding tubes 92a and 93a in the region of the two lateral carriers 92 and 93 and are fastened on these. This assembly aid is illustrated only on one side of Fig.2, the illustration of the second guiding on the other side has been omitted for the sake of clarity. As soon as the bolted joints of these two lateral carriers 92 and 93 are detached, the lateral carriers 92 and 93 can be pulled away from the central carrier 91 S. together with the drive 8 by means of this guidance without any problem.

By this arrangement of the drives 8 the interior of the basic body of the milling drum 7 is completely enclosed from the outside and thus protected. By providing the drives 8 inside of the milling drum 7 no additional force transmitting elements, like chain or the like are necessary between the drives 8 and the milling drum 7. Since the mountings of the drives 8 are simultaneously that of the milling drum 7, no additional mountings are required for the milling drum.

Since the shell 71 of the milling drum is laterally open in the region of both outside tubes 71b and 71c up to the drives 8 and thus loosened material may enter into the interior of these two tubes 71b and 71c, in this region at both ends of the lateral carriers 92 and 93 repelling means are provided which would strongly reduce the entering of the material and repel already entered material and convey it to the outside.

The transport space of the loosened material of the milling drum 7 is the annular space between the shell 71 of the milling drum and the cutting circle diameter By increasing this space from the outside towards the centre a solution is achieved which suits the actual passing through of the conveyed material. By means of the two inclined transitions 71d and 71e a smooth transition is achieved between the regions having the different diameters D I and D 2 which can be technologically easily produced and affects a favourable material flow.

For the loosening of the material from the block to be mined and its further conveying in the region of the milling drum 7 and its directed transfer on to the discharge belt 11, the fitting of the milling drum 7 with cutting tools and material guiding devices is important in conjunction with the interaction with the discharge chute The fitting of the milling drum 7 with cutting tools 72, S. ejector plates 73 as well as with lateral and helical guide plates 74 and 75 is illustrated perspectively in Fig.4 for one type of material having a low hardness and strength like, for example, brown coal, and according to Fig.5 schematically as a development on the shell 71 of the milling drum. The cutting tools 72, comprises the welded on milling cutter holders 72a and the exchangeable milling cutters 72b, are provided on the circumference of the shell 71 of the milling drum. The cutting edges of the milling cutters 72b are set to a common cutting circle diameter D s So that milling cutters 72b of the same size could be used, the milling cutter holders 72a are also of different lengths to fit the milling drum based on the different diameters D i and D 2 and thus constructed to equalise the differences. The fitting of the milling drum 7 on the shell 71 of the milling drum with cutting tools 72 depends essentially from the specific applications, the configuration of the machine, the intended delivery capacity and the grain size in which the material is to be excavated. This concerns first of all the milling cutter 72b, their numbers and arrangement relative each other on a helix, whereby the helix angle of these helices is also optimised to suit the properties of the material to be excavated. The cutting tools 72 are arranged on the circumference of the milling drum 7 behind each other in the direction of rotation on one or several helices extending from the outside towards the centre symmetrically or offset to each other. On this occasion the symmetrical arrangement of the helices can be used when the milling cutters 72b are positioned relatively close and evenly to each other.

In contrast to this, the arrangement illustrated is preferred when using fewer milling cutters 72b positioned at a greater distance from each other, thus reducing the dynamic loads during milling. This means that by engaging fewer, yet always almost the same number of milling cutters 72b a quieter operation of the milling drum 7 can be achieved. Since in this case the milling drum 7 is used for the mining of brown coal and special requirements are placed on the size of its lumps, the milling cutters 72b have to be positioned relatively far from each other. Since, however, due to the steps on the circumference of the drum the space for the material to be excavated is smaller in the two lateral regions than in the central region and although it is sufficient for smaller amounts of material, in the case of larger lumps problems may arise in the annular space between the stepped shell 71 of the milling drum and the cutting circle diameter This will be prevented by the deliberately obtained smaller lumps in both outside regions. For this reason the milling cutters 72b are provided there at a smaller distance from each other than in the central region. They are arranged on the outside on two helices, however, in contrast to this, in the central region only one of these extended helices is fitted with milling cutters 72b. In the central region of the drum the guide plates are replaced by ejector plates 73 provided behind the milling cutters 72b, due to which the transfer of the conveyed material to the discharge belt 11 will be evenly distributed.

Since in the central region of the drum the second helix is not fitted with milling cutters 72b for the purpose of achieving larger lumps, this is fitted only with ejector plates 73. The objective of arranging the helices offset at 90' relative each other is the reduction of the jolts on the milling drum 7 during the mining operation caused by the greater distances between the milling cutters 72b and provide an even better continuity of the transfer of the conveyed material on to the discharge belt 11. The milling cutters 72' provided on both external edges of the milling drum 7 have the additional task to produce the necessary lateral free cut thus preventing wedging of the milling drum 7. For this purpose the same milling cutters 72b can be used as the ones used on the entire shell 71 of the milling drum, merely the milling cutter holders 72a need to be so constructed and fastened that the cutting edges of the milling cutters 72b are inclined to the outside.

To enable the targeted transfer of the loosened material without loss from the milling drum 7 on to the following discharge belt 11, the discharge chute 10 is provided as part of the milling drum module 6. This should fulfil three tasks: the transport space following the block to be excavated is limited and thus the conveying of the material is supported in both the rotational and axial directions, S: the transfer position of the material is to be limited in a localised manner accurately to the discharge belt 11, to enable an elimination of the undulations (levelling) of the cut surface 15, which at the same time is travelling surface of the machine, and the pick-up of excess material with the support of the milling drum 7.

So that the receiving chute 10 could fulfil these three tasks, it has a stable construction and has a transfer opening. Fig.6 shows the arrangement of the discharge chute 10 between the milling drum 7 and the discharge belt 11. According to Fig.7 it comprises the curved shield 101. It surrounds the milling drum 7 over its entire width. Its height extends from the top edge of the layer to be cut, which is simultaneously the travelling plane of the machine, up to a height which corresponds to approx. 3/4 of the diameter of the milling drum 7, at a certain distance from its cutting circle diameter Thus the shield 101 surrounds the milling drum 7 on the side of the machine by an angle of approx. 1100. In the region in front of the discharge belt 11 an opening with a principally rectangular shape is provided in this shield 101 for the guide and conveying tunnel 102 to transfer the material from the milling drum 7 to this discharge belt 11. The opening is approx. 20 smaller than the discharge belt 11 to achieve a reliable transfer of the material and to avoid losses during the •go• transport. For a longer service life the shield 101 is provided with exchangeable plastic linings or it has a plastic coating.

In the bottom region the shield 101 has a stable wear edge 103, comprising segments 103a, which can be replaced after having reached a certain degree of wear.

The shield 101 is combined by ribs and lateral plates to form a stable welded construction. To illustrate this, the discharge chute 10 is shown in Fig.6 without its shield 101.

The discharge chute 10 combined in this manner is joined with the superstructure 3 of the surface mining machine at the top by bolts in both eyelets 104 directly and at the bottom by the two struts 14 indirectly. Each of the two struts 14 is joined on one side to the superstructure 3 and on the other side to the discharge chute 10 by means of pin joints. Both struts 14 have a construction whereby their lengths can be altered. The alteration of the length is achieved by providing various intermediate pieces/spacers on a hinging point or by two-part struts, which are connected by means of an adjustable and lockable threaded part, or by means of a hydraulic cylinder which is mechanically locked after having been adjusted. By virtue of this the annular gap between the cutting circle of the milling drum 7 and the discharge chute 10 can be changed and the distance from the wear edge 103 to the cutting surface/plane will be corrected to adjust for the wear of the cutting tools 72. At the same time the discharge chute 10 is pivoted about the top hinge, by means of which it is joined to the superstructure 3 of the surface mining machine. If both pins of the top hinge have an eccentric construction, the differences of the gap between the cutting circle diameter D s of the cutting tools 72 and the shield 101 or the wear edge 103 of the shield 101 to the layer can be equalised. By using adjusting members the eccentric pins can be adjusted automatically. For maintenance and repair works the rear suspension of the discharge chute 10 can be simply released and afterwards swivelled away from the milling drum 7 by means of a hoist.

Since the material after having been loosened from the block to be excavated by the cutting tools 72 used for the cutting has S the tendency to move from these four cutting tools 72 towards both sides before it is seized by the following cutting tools 72 and the helical guide plates 75, according to Figs.8 and 9 end rings 16 are provided at both ends of the milling drum 7 on its shell 71, the outside diameter of which end ring is smaller than the cutting circle diameter D s of the cutting tools 72.

0 These end rings 16 comprise individual segments 16a, which in the direction of rotation commence behind the two cutting tools 72' intended for the free cutting and reach up to the guide plate 75 which belongs to the following cutting tool 72. This version is illustrated in Fig.8 on the right half of the milling drum. In a second version, shown in the same figure on the left half of the milling drum, these segments 16a are divided once again into sub-segments 16a' in the direction of the centre of the machine for a better removal of the material, and their ends, as it is shown in Fig.5, are bent inwards as lateral scoops. Parallel to these end rings 16, in both external regions of the discharge chute 10, an end ring segment 17, having an inside diameter greater than the shell 71 of the milling drum, is provided extending over the entire height of the shield 101. An end ring segment 17, associated with the discharge chute 10, and an end ring 16, associated with the milling drum 7 and comprising segments 16a or sub-segments 16a', together form a labyrinth-shaped closure. By virtue of this lateral closure, formed in this manner, of the annular conveying space for the material, in the region of the milling drum 7 only a very small portion of the material can escape from the block to be excavated after having been loosened.

Accordingly, the conveying losses are considerably reduced.

0000 r o ooeo e oo S o S

Claims (6)

1. A milling drum module for a surface mining machine comprising a milling drum working in the downcut manner, of drives for the milling drum, of elements guiding the material between the milling drum and the subsequent discharge belt and of a fastening of the milling drum on the surface mining machine, wherein the milling drum is arranged horizontally about its longitudinal axis and simultaneously axis of rotation in front of the travelling gear transversely to the direction of travel, is mounted on both sides in the region of its faces and is driven and on its circumferential surface cutting tools and guide plates are provided, and the material is loosened from the block to be excavated, carried away in the direction of rotation and afterwards transferred on to a discharge belt which is narrower than the cutting width of the milling drum, wherein the transport space of the loosened material in the region .:Of of the milling drum is the annular space between the shell of the milling drum and the cutting circle diameter, characterised in that the basic body of the milling drum is a shell of the milling drum and accommodates on both sides a drive each and the drive shafts of the drives are joined to the milling drum and the stationary drive housing is joined to the carrier frame and the mountings of the drives are at the same time the mountings of the milling drum and in the direction of rotation of the milling drum following the block to be excavated a discharge chute is provided for the guiding of the material and the targeted transfer of the material on to the following discharge belt, which discharge chute surrounds curved the milling drum at a distance from its cutting circle diameter from the top edge of the cut surface in the direction of rotation of the drum by an angle of approx. 110 and thus limits on the outside the transport space for the loosened material and in the region of the intended transfer of the material on to the discharge belt is provided with a guide and conveying tunnel and the discharge chute is joined to the surface mining machine by a top hinge and two bottom struts which are longitudinally adjustable.

2. A milling drum of a milling drum module for a surface mining machine according to claim i, characterised in that the shell of the milling drum has a tubular and laterally open construction and is made up from a wide central tube having a defined diameter and two outside tubes which are shorter and have a larger diameter than the central one, the central tube is provided on both circular outsides with a flange each, the diameter of these flanges is smaller than the inside diameter of the central tube and a bevelled transitions is provided between each of the lateral tube and the flange and thus between the cutting circle diameter and the outside diameters of the shell of the milling drum an increase of space occurs from the outside regions towards the central region which is made to suit the passing through of the conveyed material, and in the interior of the shell of the milling drum encased drives are provided on both sides in the longitudinal axis and the axis of rotation of the milling drum, while each of these drives comprises a motor with a stationary housing part and a transmission with a drive shaft, while the stationary housing part and the rotating drive shaft are provided with a flange and the two flanges of the drive shaft are connected axially with the flanges of the milling drum and the two flanges of the stationary housing part of the motor are connected with the free ends of the carrier frame which are also provided with S a flange and the connecting leads for the drives are guided inside the profiled section of the carrier frame to the drives.

3. A carrier frame of a milling drum module for a surface mining machine according to claim i, characterised in that it is made up from a horizontal central carrier provided on the superstructure of the surface mining machine and two 'I vertical lateral carriers detachably connected with central carrier and the vertical surfaces facing each other are bolted joints with centring and as assembly aids guide tubes are provided in the horizontal central carrier on the right and left which protrude in the region of the two lateral carriers, which guide tubes in the region of the two lateral carriers are surrounded by sliding tubes fastened in the lateral carriers and the two lateral carriers are so angled twice at the bottom that in the top half diameter of the milling drum they protrude with their flanges into the milling drum.

4. A discharge chute of a milling drum module for a surface mining machine according to claim 1, characterised by the combination of the following features, known per se: Sa shield surrounds the milling drum on the side averted from the block to be excavated at a distance to the cutting circle diameter over the entire milling width and at the height from the layer to be cut by an angle of approx. 1100, 0the bottom edge of the shield is provided with a wear edge which comprises exchangeable segments, the shield is reinforced on its rear by a carrier and support construction, the discharge chute is joined with the superstructure at the top parallel to the axis of rotation of the milling drum by a hinge and at the bottom by a right and left double-hinge via a strut each as intermediate part, and Sin the discharge chute an opening for the transfer of the •3 -material on to the discharge belt is provided which is constructed as a guide and conveying tunnel in the flight trajectory of the material.

A milling drum of a milling drum module for a surface mining machine according to claim i, characterised in that the annular transport space for the loosened material is limited by a right and left end ring, wherein each of these end rings comprises segments arranged on the edge of the drum and extend from the rear of a milling cutter provided for the free cut up to the commencement of the helical guide plate of the milling cutter for the free cut following in the direction of rotation of the drum and these segments may be divided in their lengths once again into sub-segments, the ends of which are bent inwards as side scoops, and the outside diameter of the end ring is smaller than the cutting circle diameter of the cutting tools and on the discharge chute in both external regions on the curved side directed towards the milling drum extending over its entire height parallel to the milling drum end rings comprising segments or sub-segments are provided inside on the side of the centre of the machine a further end ring segment is provided, and so on both sides the end ring of the milling drum together with end ring segment form a closure in the form of a simple labyrinth.

6. A milling drum of a milling drum module for a surface mining machine according to claims 1 and 2, characterised in that when using milling cutters of the same size the milling 6:04 cutter holders are so dimensioned that the tips of all eeeo milling cutters forma common cutting circle diameter despite the different sizes of the diameters D, and D 2 of the milling drum. oeoe e oe DATED: 30th August, 1999 0*@S PHILLIPS ORMONDE FITZPATRICK Attorneys for: MAN TAKRAF FORDERTECHNIK GmbH SS 0 *ooSOo *°oeS S