Milling Device for Excavating Mining Materials

Abstract

A milling device for excavating mining materials is disclosed. The milling device comprises a milling drum rotatable about a drum axis; a first group of excavating heads arranged around a periphery of the milling drum and driven to rotate about a first rotational axis extending substantially radially to the drum axis; and a second group of excavating heads arranged around the periphery of the milling drum and rotatable about a second rotational axis extending substantially radially to the drum axis. The first group of excavating heads includes a plurality of first excavating tools configured to perform a first, cutting operation, and the second group of excavating heads includes a plurality of second excavating tools configured to perform a second excavating operation different from the first, cutting operation.

1 . A milling device for excavating mining materials, the milling device comprising:
 a milling drum rotatable about a drum axis;   a first group of excavating heads arranged around a periphery of the milling drum and driven to rotate about a first rotational axis extending substantially radially to the drum axis;   a second group of excavating heads arranged around the periphery of the milling drum and rotatable about a second rotational axis extending substantially radially to the drum axis; wherein   
       the first group of excavating heads includes a plurality of first excavating tools configured to perform a first, cutting operation, and
 the second group of excavating heads includes a plurality of second excavating tools configured to perform a second excavating operation different from the first, cutting operation. 
 
     
     
         2 . The milling device of  claim 1 , wherein the second excavating operation is a blunt compression operation acting against a tensile strength of the mining material. 
     
     
         3 . The milling device of  claim 1 , wherein the second excavating tools include a disc-like shape with a blunt contact region configured to perform the second excavating operation. 
     
     
         4 . The milling device of  claim 3 , wherein the blunt contact region includes a conical cross-sectional shape in a plane including the second rotational axis, the conical cross-sectional shape further including
 a radially outer face with respect to the drum axis,   a lateral face having a diameter increasing in a radial outward direction with respect to the drum axis, and   a blunt edge connecting the lateral face and the radially outer face.   
     
     
         5 . The milling device of  claim 4 , wherein the radially outer face includes a planar portion at a radially inner side with respect to the second rotational axis, and a bevel portion at a radially outer side with respect to the second rotational axis. 
     
     
         6 . The milling device of  claim 5 , wherein
 the second rotational axis and a radial direction of the drum axis confine a first angle,   the bevel portion and the planar portion confine a second angle, and   the second angle is substantially equal to the first angle.   
     
     
         7 . The milling device of  claim 1 , wherein the first group of excavating heads and the second group of excavating heads are alternately arranged on the periphery of the milling drum. 
     
     
         8 . The milling device of  claim 1 , wherein,
 the first excavating tools include a first maximal radial distance from the first rotational axis,   the second excavating tools include a second maximal radial distance from the second rotational axis, and   the second maximal radial distance is substantially equal to the first maximal radial distance.   
     
     
         9 . The milling device of  claim 1 , wherein,
 the first excavating tools include a first maximal radial distance from the drum axis,   the second excavating tools include a second maximal radial distance from the drum axis, and   the second maximal radial distance is substantially equal to the first maximal radial distance.   
     
     
         10 . The milling device according to  claim 1 , wherein the second group of excavating heads includes a shaft carrier portion disposed on a radially inner side with respect to the drum axis, and a tool carrier portion disposed on a radially outer side with respect to the drum axis, the shaft carrier portion being driven to rotate about the second rotational axis, the tool carrier portion being configured to accommodate the second excavating tools, the tool carrier portion further being rotatably mounted on the shaft carrier portion and being rotatable about a third rotational axis, wherein the third rotational axis is offset from the second rotational axis by a predetermined value. 
     
     
         11 . The milling device of  claim 1 , wherein the first group of excavating heads includes a plurality of slot cutting rings arranged in an axial of the first rotational axis, each slot cutting ring accommodating the plurality of first excavating tools, and
 the second group of excavating heads includes a plurality of disc-shaped rings arranged in an axial direction of the second rotational axis, each disc-shaped ring accommodating the plurality of second excavating tools and being configured to engage with slots produced by the respective slot cutting ring.   
     
     
         12 . The milling device of  claim 1 , wherein the first rotational axis is identical with the second rotational axis, and the first excavating tools are arranged on a radially outer side with respect to the drum axis and the second excavating tools are arranged on a radially inner side with respect to the drum axis. 
     
     
         13 . A method for excavating mining materials with a milling device, the milling device including a milling drum rotatable about a drum axis, a first group of excavating heads driven to rotate about a first rotational axis and accommodating a plurality of first excavating tools, a second group of excavating heads rotatable about a second rotational axis and accommodating a plurality of second excavating tools different from the first excavating tools, the first group of excavating heads and the second group of excavating heads being alternately arranged around a periphery of the milling drum, the method comprising:
 rotating the milling drum about the drum axis in a direction towards the mining material thereby engaging the first excavating tools with the mining material;   concomitantly rotating the first group of excavating heads about the first rotational axis thereby performing a first, cutting operation with the first excavating tools;   
       rotating the milling drum further in the direction towards the mining material thereby engaging the second excavating tools with the mining material; and 
       performing a second excavating operation different from the first, cutting operation using the second excavating tools. 
     
     
         14 . The method of  claim 13 , wherein the first, cutting operation and the second excavating operation are performed in the same area of the mining material. 
     
     
         15 . The method of  claim 13 , wherein the second excavating operation further includes
 performing a blunt compression operation on the mining material, the blunt compression operation acting against a tensile strength of the mining material;   
       engaging the second excavating tools with slots generated in the mining material during the first, cutting operation, and
 breaking out remaining mining material by rotating the milling drum further in the direction towards the mining material.