초록 ▼

A marine propulsion system includes a steerable lower gearcase portion and a drive mechanism including a chain drive for driving dual counterrotating propellers. The dual propellers are rotatably mounted to the lower steerable gearcase portion by means of inner and outer coaxially extending propelle

A marine propulsion system includes a steerable lower gearcase portion and a drive mechanism including a chain drive for driving dual counterrotating propellers. The dual propellers are rotatably mounted to the lower steerable gearcase portion by means of inner and outer coaxially extending propeller shafts. A sprocket is mounted to each propeller shaft, and first and second chain portions extend between the propeller shaft sprockets and a pair of upper drive sprockets, preferably disposed above the water line during boat operation. Coaxially extending inner and outer drive shafts are interconnected with the engine output shaft, and are adapted for counterrotation in response to rotation thereof. The coaxial drive shafts are interconnected with the upper drive sprockets for driving such sprockets in opposite rotational directions, thereby resulting in movement of the first and second chain portions in opposite directions. The longitudinal axis of the inner and outer drive shafts defines the steering axis about which the lower steerable gearcase portion is pivotable.

대표청구항 ▼

In a marine drive for a boat, said marine drive including an engine having a rotatable output shaft, the improvement comprising: a depending gearcase having an upper portion and a lower steerable portion pivotably mounted to said upper portion so as to ba pivotable about a steering axis; a first pro

In a marine drive for a boat, said marine drive including an engine having a rotatable output shaft, the improvement comprising: a depending gearcase having an upper portion and a lower steerable portion pivotably mounted to said upper portion so as to ba pivotable about a steering axis; a first propeller shaft rotatably mounted to said lower steerable portion of said gearcase; a second propeller shaft rotatably mounted to said lower steerable portion of said gearcase; a first propeller mounted to said first propeller shaft; a second propeller mounted to said second propeller shaft; flexible drive means drivingly interconnected between said engine output shaft and said first and second propeller shafts, said flexible drive means including a first portion for driving said first propeller shaft and a second portion for driving said second propeller shaft; and counterrotation drive means for driving said first and second portions of said flexible drive means in opposite directions in response to rotation of said engine output shaft, and thereby providing rotation of said first and second propeller shafts in opposite rotational directions, said counterrotation drive means accommodating pivoting movement of said lower steerable portion of said gearcase about said steering axis.