Patent ID: 6935986

Claim:
A two speed gearbox mounted in-line for driving a hub, the gear box comprising: a gearbox casing adapted to journal mount about an input drive shaft and output shaft; a central planetary gear carrier assembly rotatably mounted within the gearbox casing comprising: a sun gear to accommodate and be driven by the input drive shaft; a plurality of planetary gears; a ring gear associated with a coupling to accommodate and drive the output shaft; a planetary gear carrier, the planetary gear carrier supporting and interconnecting the planetary gears; a low speed clutch assembly with a plurality of fixed discs mounted to the gearbox casing adapted to selectively engage a plurality of rotating discs there between attached to the ring gear of the plane gear carrier assembly; a high speed clutch assembly with a plurality of fixed discs housed within a carrier mount adapted to selective engage a plurality of rotating discs there between attached to the sun gear of the planetary gear carrier assembly; and an engaging/disengaging high speed hydraulically powered spring return piston operably associated with the high speed clutch assembly having a locking pin to hydraulically secure the planetary gear assembly to the casing to prevent slippage, and selectively secure the sun gear of the planetary gear carrier when engaged; an engaging/disengaging low speed hydraulically powered spring return piston attached to the casing and operably associated with the low speed clutch assembly to selectively hydraulically secure the ring of the planetary gear assembly, when engaged; and activation means to selectively activate the desired high speed and low speed hydraulically powered spring return pistons to provide the desired operating speed mode.