Gearing units for use with mining apparatus

A drive unit for use with mineral mining apparatus;

• said unit comprising a housing, an input shaft extending into the housing, an output shaft extending into the housing, gearing at least including planetary gearing, within the housing drivably interconnecting the input shaft to the output shaft, a rotatable component of the planetary gearing which when held stationary permits drive to be transmitted through the gearing and when released to rotate interrupts the drive, brake means for selectively holding the rotatable component of the planetary gearing stationary, said brake means being composed of a first plate carrier and a second plate carrier, biasing means for causing the plates of the carriers to engage one another to rotatably lock the carriers together, a pressure chamber for receiving hydraulic fluid used to oppose the biasing means and to disengage the plates of the carriers, a toothed coupling drivably interconnecting the first plate carrier to the rotatable component of the planetary gearing, holding means for holding the second plate carrier stationary in relation to said housing, a load sensor incorporated in the holding means for providing an electrical signal indicative of loading, and means responsive to said signal to provide fluid to flow to the pressure chamber to release the rotatable component of the planetary gearing in the event of overloading.