Patent ID: 6220906
Filing Date: 2001-04-24
Classification: B63H

Abstract:
A marine propulsion assembly comprising:a drive shaft;a first propeller fixed to said drive shaft and turnable therewith in a first direction, said first propeller having a hub, propeller blades fixed to said hub, and an annular ring fixed to outboard tips of said blades;a first annular array of gear teeth disposed on said first propeller annular ring and turnable therewith;a second propeller aligned with said first propeller having a hub, propeller blades fixed to said second propeller hub, and an annular ring fixed to outboard tips of said second propeller blades;a second annular array of gear teeth disposed on said second propeller annular ring;bevel gears disposed between said first and second propellers, each of said bevel gears having one array of teeth engaged with said first and second annular arrays of gear teeth, said bevel gears transmitting rotation of said drive shaft and said first propeller to said second propeller, such that said second propeller turns in an opposite direction relative to said first propeller;a cage in which said first propeller is disposed, said bevel gears being rotatable mounted in said cage; anda second shaft rotatably disposed at one end in said first propeller hub and at a second end in said cage, said second propeller hub being fixed to said second shaft.