Zf Friedrichshafen Ag

Brunswick Corporation

Zf Marine Propulsion Systems Miramar, LLC

Dave Gruenwald

Bryan Danner

Andrew Orvieto

Keith Stanley

Stephen Crane

A marine propulsion system, supported by a strut, which comprises an inner propeller shaft supporting a first propeller adjacent a trailing end thereof, and the inner propeller shaft is connected to the drive shaft for receiving and supplying a first portion of torque to the first propeller as well as transfer thrust, generated by the first propeller, along the inner propeller shaft back to the drive shaft. An outer propeller shaft supports a second propeller adjacent a trailing end thereof, and the outer propeller shaft surrounds the inner propeller shaft. A planetary gear assembly receives a second portion of the torque and supplies the torque to the outer propeller shaft so that the second propeller rotates in an opposite direction to the first propeller. A portion of the planetary gear assembly is accommodated vertically above a flat end face of the strut for reducing hydrodynamic drag of the strut.

Marine propulsion system supported by a strut

A marine propulsion system, supported by a strut, comprising an inner propeller shaft supporting a first propeller adjacent a trailing end thereof, and the inner propeller shaft is connected to the drive shaft for receiving and supplying a first portion of torque to the first propeller as well as transfer thrust, generated by the first propeller, along the inner propeller shaft back to the drive shaft. An outer propeller shaft supports a second propeller adjacent a trailing and thereof, and the outer propeller shaft surrounds the inner propeller shaft. A differential gear set receives a second portion of the torque and supplies the second portion to the outer propeller shaft so that the second propeller rotates in an opposite rotational direction to the first propeller. The thrust, generated by the first and the second propellers, is conveyed along either the inner or the outer propeller shafts, to the drive shaft.

A rotational molding method is provided consisting in a first method of spraying the inner mold area with an acrylic polyethylene alloy prior to loading the resin into the mold. The mold is then heated, rotated and cooled to form the molded part. The part is provided with a shinier and harder surface layer as compared to previous rotational molding methods. In a second method, in lieu of spraying, the acrylic polyethylene alloy is loaded into the mold with the resin. In the third and fourth methods, a drop box is provided for releasing resins into the mold. Other materials, in addition to acrylic polyethylene, can also be used with the various methods.

Growing community of inventors

Oshkosh, WI, United States of America

Dave Gruenwald