Patent ID: 7475947

Claim:
A mining machine comprising, a mobile frame including a front end portion; a plurality of rotor assemblies including a plurality of rotor cutter arms, the plurality of rotor assemblies being disposed in spaced relation on the front end portion of the mobile frame; a cutter drum assembly disposed forwardly of the front end portion, the cutter drum assembly including: an axis of rotation disposed transversely across the front end portion of the mobile frame; a first end drum section including: a first shaft extending along the axis of rotation, the first shaft including a first bore extending along the axis of rotation; a first end drum being secured to the first shaft; a first end drum extension disposed coaxially about the axis of rotation; a first piston being relatively rotatably disposed in the first bore and being fixed with respect to the first end drum extension, the first piston being displaceable along the axis of rotation between an extended configuration of the first end drum extension and a retracted configuration of the first end drum extension; a first coupling transferring torque between the first end drum and the first end drum extension; a second end drum section including: a second shaft extending along the axis of rotation and being axially spaced from the first shaft, the second shaft including a second bore extending along the axis of rotation; a second end drum being secured to the second shaft; a second end drum extension disposed coaxially about the axis of rotation; a second piston being relatively rotatably disposed in the second bore and being fixed with respect to the second end drum extension, the second piston being displaceable along the axis of rotation between an extended configuration of the second end drum extension and a retracted configuration of the second end drum extension; a second coupling transferring torque between the second end drum and the second end drum extension; and an intermediate drum section being disposed coaxially with the axis of rotation and extending between the first and second shafts, wherein the first and second couplings each comprise an axially sliding coupling, and each axially sliding coupling comprises first and second sets of jaws, each of the first sets of jaws is disposed on a corresponding one of the first and second end drums, and each of the second sets of jaws is disposed on a respective corresponding one of the first and second end drum extensions.