Variable pitch marine propeller with hydrodynamic shifting
US5219272A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1991 |
| Grant date | Jun 15, 1993 |
| Priority date | — |
| Expiry date | Dec 2, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB63H1/26
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A marine propeller includes a hub rotatable about a longitudinal axis and having a plurality of blades extending radially outwardly therefrom and pivotable about respective radial pivot axes between a low pitch position and a high pitch position. Each blade has a hydrodynamic force characteristic which shifts the location of the resultant hydrodynamic force on the blade in a direction aiding up-pitching of the blade, and increasing the up-pitching pivot moment with decreasing angles of attack. A counteractive hydrodynamic force generating area is provided on the negative pressure backside surface of the blade and shifts the location of the resultant hydrodynamic force on the frontside surface forwardly with decreasing angle of attack. The blade is pivoted by increased water flow along the counteractive hydrodynamic force generating area with decreasing angles of attack, which increased water flow generates a backside hydrodynamic force on the blade at the counteractive hydrodynamic force generating area spaced from the pivot axis by a moment arm provided by the section of the blade between the pivot axis and the counteractive hydrodynamic force generating area, such that the backsi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.