AU642294B2 - Shearer - Google Patents

Description

-1I- *gO* 0 00 0 8 *0 00 09 ~0 *0 19 00 AUSTRAL IA PATENTS ACT 1990 TRUE COPY COMPLETE SPECIFICATION I certify that the following 9 pages are a true and correct copy of the description and claims of the original complete 'specification in respect of an invention entitled: "SHEARER" 0 ~Name of Applicant:. JOHN LENNON WALLACE by Signature Atllow Institute of Patent Attorneys of Australi;, of $UELSTON WATERS -2- The present invention relates to underground mining equipment and in particular to a long wall shearer.

The invention has been developed primarily for use with coal mining and will be described hereinafter with reference to that application. However, it will be appreciated that the invention has not been limited to this particular field and is also suitable for the mining of other stratified deposits.

Generally, a layer or seam in a stratified deposit of coal will not vary appreciably in thickness over a wide area. As it is preferable to simultaneously excavate over the whole thickness of the seam, the use of a shearer including a cutting disc or discs which provide *60* a cutting height matching the seam thickness simplifies So* 15 the cutting operation.

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S* Although the thickness of the seam to b, excavated

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may not greatly vary, such a layer generally does not have a uniform gradient. It is necessary to adjust both the top and bottom cutting horizons produced by the shearer so that only the coal will be extracted and not o* adjacent rock. The top horizon is easily visible to an operator and any required adjustments to account for seam contour can be made with reasonable accuracy. However, the bottom horizon is obscured by the associated conveyor

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assembly and the cut material.

Hitherto, the use of a single disc shearer has taken advantage of the relatively uniform seam thickness. The easily visible "'op horizon is followed by 3 cost o See.

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making suitable height adjustments to avoid extraction of unwanted material. The bottom cutting horizon is in consequence adjusted as the disc follows the contour of the seam. However, if the desired extraction height is not of the same dimension as the diameter of the cutting disc, the shearer will not be able to remove all the available coal in a single pass. Accordingly, the efficiency of the single disc shearer is reduced as either a second run across the seam will be required, or large quantities of coal will be left .unmined.

To ameliorate this problem shearers including two cutting discs have been used. Such shearers generally include a raised disc and a following lowered disc. The discs are independently operated such that a variable 15 cutting height can be achieved. However, to correctly maintain the cutting horizons to accord with the seam extremities, a complex control system is necessary.

Furthermore, as the horizon cut by the lowered disc is generally obscured by conveyors and cut material, it is 20 difficult to ascertain the correct cutting horizon as the gradient changes across the width of the seam.

Many methods 6f horizon control have not been entirely successful due to highly complex measurement techniques which usually involve the use of very sensitive transducers which are not sufficiently durable to withstand the harsh working conditions.

After the completion of a run across the seam, the shearer and associated apparatus are moved into the Cc~o Ce..

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See @0 C 4 area that was just excavated such that a new run can be commenced. The shearer conveyor assembly will now follow the contour of the completed run. As prior art horizon control systems have used the conveyor assembly as a reference any errors occurring in the completed run are now added to those occurring during the present run.

It is an object of the present invention, at least in its preferred embodiment, to overcome or substantially ameliorate at least some of these deficiencies of the 10 prior art.

According to the invention there is provided a shearer for excavating an underground deposit between an 0 upper and lower horizon, said shearer including a base assembly, two arms each rotatably mounted at or adjacent 15 respective first ends to said base assembly, two cutting discs rotatably mounted at or adjacent respective second ends of said arms for excavating between two cutting horizons respectively associated with each disc, and 0* adjustment means for actuating one of said arms such that one of said cutting horizons corresponds to one of said upper or lower horizons and for selectively maintaining said arms in a fixed angularly spaced apart configuration such that the other cutting horizon corresponds to the lower or upper horizon respectively.

Preferably, the adjustment means adjusts one of the cutting horizons to correspond with the upper horizon and by way of consequent adjustment brings the other cutting 5 o 0*0 0@ 0 go so ofr *0b S 0 8 S

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Preferably also, the adjustment means are manually operable for allowing an operator to adjust the cutting horizons to correspond with the upper and lower horizons.

In a preferred form, the adjustment means includes a connection element rotatably mounted to and extending between an intermediate portion of each arm. The adjustment means further including an hydraulic ram extending between one of the arms and the base assembly for allowing the adjustment of the cutting horizons.

Preferably also the arms are rotatably mounted to the base assembly about the same axis.

A preferred embodiment of the invention will now be described by way of example only, with r,.erence to the 15 accompanying drawings in which: Figure 1 is a side view of the shearer acco.ding to the inventio; Figure 2 is the shearer of Figure 1 with the arms in an inverted configuration; 20 Figure 3 is the shearer of Figure 1 with the linkage extended; and, Figure 4 is a'side view of the shearer of Figure 3 with the arms in an inverted configuration.

Referring to Figure 1 and Figure 3, a shearer 1 25 for excavating an underground coal seam 2 between a roof and floor hbrizon 3 and 4 includes a base assembly 5 and two arms 6 and I each rotatably mounted at one end 8 to e base 5 by pin 9.

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5 ii* @50 0 9 Seo, 0.00 6 Two cutting discs 10 and 11 are rotatably mounted at second ends 12 of respective arms 6 and 7 for excavating between two cutting horizons 13 and 14 defined by the tangents at the vertical extremities of discs and 11 respectively. Adjustment means in the form of an hydraulic ram (not shown) actuates arm 6 such that cutting horizon 13 corresponds to roof horizon 3. The adjustment means also includes a linkage bar in the form of an hydraulic ram 15 rotatably mounted to and extending between an intermediate portion of arms 6 and 7 for selectively maintaining a predetermined angle between the arms so that once horizons 13 and 3 correspond, so will horizons 14 and 4.

Base assembly 5 is able to progress along a haulage 15 system in the form of tracks 16. A conveyor assembly 17 co-extends with tracks 16 to allow movement of the excavated material to a more convenient point for subsequent transportation.

Referring in particular to Figure 1, shearer 1 is 20 configured such that cutting horizon 13 will correspond to horizon 3. Ram 15 is then adjusted such that cutting horizon 14 corresponds to horizon 4. As base assembly progresses to the right, with disc 10 leading, an operator adjusts cutting horizon 13 by manual controls such that at all times cutting horizon 13 follows roof horizon 3. The action of ram 15 in maintaining arms 6 and 7 in a fixed angularly spaced apart relationship has 7 seem

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0 at 5 5 the effect that any adjustment of disc 10 to account for the contour of roof horizon 3 will effect a consequent adjustment of disc 11 to compensate for a corresponding change in the contour of floor horizon 4.

When completing such a run across the deposit, shearer 1 is moved into the cavity just excavated so as to complete another run in the opposite direction. In order to achieve the best horizon control it is necessary that the easily visible raised disc is also leading the lowered disc. It is also necessary to maintain the predetermined angle between arms 6 and 7 such that the excavation height is maintained, that is, the distance between cutting horizons 13 and 14 needs to be maintained. Preferably this is achieved as illustrated in Figure 2 where corresponding features are denoted by corresponding reference numerals. Arms 6 and 7 are rotated such that discs 10 and 11 are now positioned such that cutting horizons 13 and 3.4 correspond to horizons 4 and 3 respectively. The arms are held by ram 15 in the 20 same angularly spaced apart relationship to ensure the height of the next extraction will be consistent with prior runs.

Referring to Figure 3 and 4, shearer 1 is configured to excavate a coal seam 2 having a height less 25 than that shown in Figures 1 and 2. Ram 15 is adjusted such that the angle between arms 6 and 7 is such that discs 10 and 11 will excavate only to horizons 3 and 4.

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S S o 55 -8- The adjustment of the leading disc to follow the horizon contour is carried out as described above. Furthermore, at the completion of a run the shearer is adjusted to the configuration of Figure 4 such that a run in the opposite direction is accurately made.

The adjustable nature of ram 15 allows the Sefficient excavation of coal seams over a large height range. The seam can be sufficiently excavated in a single pass, regardless of seam height. Furthermore, as sufficient horizon control is achieved by maintaining the predetermined angle between the arms by reference to only the roof horizon, complex control systems are not required. The present invention thus provides a flexible and simple alternative to prior art shearers.

15 Other preferred embodiments of the invention would include arms 6 and 7 being rotatably mounted about spaced apart points on base assembly 5. Furthermore, ram 15 is replaceable by a turnbuckle or other similar arrangements which are adjustable either mechanically or by hand.

20 Further preferred embodiments include two hydraulic rams 15, each associated with a respective arm 6 and 7 and both co-operatively rotating the arms to maintain horizon control and allow the leading disc to be in the raised position.

S 25 Although the invention has been described with ieference to a specific example, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (7)

1. A shearer for excavating an underground deposit between an upper and lower horizon, said shearer including a -base assembly, two arms each rotatably mounted at or adjacent respective first ends to said base assembly, two cutting discs rotatably mounted at or adjacent respective second ends of said arms for excavating between two cutting horizons respectively associated with each disc, and adjustment means for actuating one of said arms such that one of said cutting horizons corresponds to one of said upper or lower o horizons and for selectively maintaining said arms in a fixed angularly spaced apart configuration such that the other cutting horizon corresponds to the lower or upper S: horizon respectively. 99

2. A shearer according to claim 1 wherein said adjustment means adjusts one of said cutting horizons to correspond with said upper horizon.

3. A shearer according to claim 1 or claim 2 wherein said adjustment means are manually operable for allowing i// an operator to adjust a cutting horizon to correspond with the upper or lower horizons.

4. A shearer according to any one of the preceding claims wherein said adjustment means includes a connection element extending between an intermediate portion of each said arm. 10 A shearer according to claim 4 wherein the adjustment means includes an hydraulic ram extending between one of said arms and said base assembly.

6. A shearer according to any one of the preceding claims wherein said arms are rotatably mounted to said base assembly about the same axis.

7. A shearer according to any one of the preceding claims wherein said discs alternately reciprocate between a raised and lowered position as the shearer excavates back and forth across said deposit.

8. A shearer substantially as herein described with reference to the accompanying drawings. *V 4DATED this 12th Day of September, 1991 JOHN LENNON WALLACE g Attorney: LEON K. ALLEN Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS 0 *S 11 ABSTRACT A long wall shearer for excavating an underground coal seam between a roof and floor horizons including a base assembly and two arms each rotatably mounted at one end to base assembly by pin Two cutting discs (11) are rotatably mounted at second ends (12) of respective arms for excavating between two cutting horizons (14) defined by the tangents at the vertical extremities of discs (11) respectively. Adjustment means actuates arms such that cutting horizon (13) corresponds to roof horizon Hydraulic ram (15) is rotatably mounted to and extending between an intermediate portion of arms to selectively maintain a predetermined angle between 15 the arms so that once cutting horizon (13) and roof horizon correspond, so will cutting horizon (14) and floor horizon ae a