Patent ID: 7448564

Claim:
A rock crushing machine comprising; a base; a jaw assembly secured to the base, the jaw assembly being adapted to receive rock as input material to be at least partially crushed, the jaw assembly having an arcuate reaction surface that progressively engages the input material; a hollow crushing roll having an axial inner chamber that has an axis of symmetry (O), the crushing roll being a driven member having an outside surface that forms a crushing zone between it and the reaction surface of the jaw assembly; an eccentric shaft serving as a driving member that is positioned at least partially within the crushing roll, the eccentric shaft having an axis of rotation (E), the axis (E) being displaced from the axis (O) by a distance (T); a torque transmitting device positioned between the eccentric shaft and the crushing roll; and a drive mechanism that is coupled to the eccentric shaft, so that as the eccentric shaft turns, at least a portion of rotational forces are transmitted to the crushing roll by the torque transmitting device, one or more grooves being provided in an outer surface of the eccentric shaft and one or more grooves being provided within the axial inner chamber of the hollow crushing roll, the torque transmitting device including fluid that serves to transmit rotational forces between the longitudinal grooves of the eccentric shaft and those of the crushing roll, the torque transmitting device including a fluid that is viscous and transmits at least a portion of rotational energy from the eccentric shaft to the roll so that the roll may rotate with the eccentric shaft when no crushing action is taking place, and so that when crushing begins, a combination of drive torque biasing and the rotating mass-inertia of the crushing roll provide forces that promote efficient crushing action and so that when a heavy crushing force event is encountered between the jaw reaction surface and the crushing roll, slippage of the torque transmitting device allows the crushing roll to temporarily stop or reverse rotation until the heavy crushing action is completed.