Patent ID: 7418888
Filing Date: 2008-09-02
Classification: B64C,F16H,Y10T

Abstract:
1. A transmission mechanism between at least one accessory ( 1 , 2 ) and engine members ( 3 , 4 ) for driving a rotor ( 5 ) of the rotorcraft, the first engine member ( 3 ) being allocated for driving the accessory either in isolation or else together with the rotor, and a second engine member ( 4 ) being provided for driving only the rotor, the mechanism comprising a main shaft ( 7 ) provided with a rotor drive member ( 10 ), the main shaft being associated with a drive shaft ( 6 ) engaged with the first engine member via a main rotary speed differential member ( 8 ) and a selective rotary drive member ( 9 ), the selective rotary drive member being movable between a position for combined drive of the accessory and the rotor in which the main shaft engages the drive shaft, and an isolated drive position in which the main shaft does not engage the drive shaft so as to drive the accessory alone, the accessory being engaged via gearing with a secondary shaft ( 12 ) associated with the drive shaft of the first engine member, in which said gearing comprises at least one intermediate shaft ( 13 ) interposed between the main shaft and the secondary shaft, the intermediate shaft directly engaging the main shaft and engaging the secondary shaft, a second rotary speed differential member ( 16 , 17 ) being interposed between the secondary shaft and the intermediate shaft to enable the accessory to be driven either by the secondary shaft alone, being driven by the drive shaft in the isolated drive position, or by the intermediate shaft driven by the main shaft, and in which the main shaft is mounted on the same axis as the drive shaft, the selective drive member being interposed between the drive shaft and the main rotary speed differential member, the mechanism including an axial rod ( 11 ) for moving the selective drive member.