US Patent 8627907 Steering drive system and skid steer vehicle equipped therewith

A steering drive system includes a drive arrangement having a first drive and a second drive, a summing gear unit for summing driving torques of the drives on an output shaft of the summing gear unit, a first drive connection device by which the first drive is drivingly connected to a first input shaft of the summing gear unit, and a second drive connection device by which the second drive is drivingly connected to a second input shaft of the summing gear unit. The two drive connection devices are arranged in each instance such that no driving torque directed to the drives from the summing gear unit can be transmitted to the drives during a continuously produced drive connection between the drives and the summing gear unit.