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:
Aug. 27, 1996
Filed:
Jan. 18, 1995
Stephen R Speer, Spokane, WA (US);
Aerostar Marine Corporation, Spokane, WA (US);
Abstract
This invention provides a variable pitch marine propeller which is replaceable onto the drive shaft of a marine engine and which provides an exhaust channel through the propeller. To improve and increase the flow of exhaust gas through the propeller the propeller is provided with a blade shank having a cross-sectional area perpendicular to the direction of exhaust gas flow which is less than the cross-sectional area parallel to such flow in the region of the shank arm attachment. There are also provided, within the interior of the propeller, internal surfaces formed within the blade arm adjacent the shank and defining at least one channel to allow exhaust gases to flow through the arm and counterweight assembly. In addition, the propeller is formed such that the connecting region between the blade arm and the counterweight on each blade has a reduced radial width, smaller than that of the counterweight mass along an axis parallel to the drive shaft axis and parallel to the flow of exhaust gases. In addition, each counterweight mass presses against, and is supported by, an inner surface of the hub case, when the blades are positioned at their maximum pitch position. This propeller further is provided with a secondary exhaust port opening through the hub case having a valve movably secured to the propeller so as to permit opening and closing of the secondary exhaust port; the valve is biased towards the closed position when the propeller is operating at low speed or is at rest. There are further provided cascading type inlet vanes, or blades, secured to the interior circumferential surface of the hub case and positioned in the exhaust gas flow path, wherein the maximum chord length of the inlet vanes or blades, is less than the radius of the hub outer case.