The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1998
Filed:
Jul. 15, 1997
Kurt D Willows, West Bend, WI (US);
Brunswick Corporation, Lake Forest, IL (US);
Abstract
A propeller for a marine propulsion system that provides variable length exhaust paths depending upon the speed of the boat and motor. The propeller includes a propeller hub and an exhaust tube positioned within the propeller hub. The exhaust tube extends past the aft end of the propeller hub and defines a first exhaust passageway. A second exhaust passageway is positioned between the propeller hub and the exhaust tube. The second exhaust passageway is shorter than the first exhaust passageway. At low speeds, engine exhaust exits the longer first passageway, while at moderate speeds, engine exhaust exits the shorter second passageway. Therefore, the effective length of the exhaust path varies depending upon the speed of the motor, such that the length of the exhaust path is specifically tuned to several speeds of the motor.