Self-actuating variable pitch marine propeller
AssigneeNautical Development, Inc.
InventorStephen R. Speer
Life of this patent
Estimating the term…
Abstract
There is provided a self-actuating, variable pitch propeller having a plurality of blades. All of the blades are automatically movable between a first, relatively lower pitch position and a second, relatively higher pitch position, substantially simultaneously and equally in response to achieving a predetermined combination of propeller rotational speed and hydrodynamic loading on the propeller blades. The blades are releasably locked to prevent the pivoting of each blade when in the locked position. The locking means are released by actuating means activated by the combined effects of centrifugal force and hydrodynamic loading.
Claims11
A variable pitch marine propeller comprising a hub case;
- drive securing means designed to secure the propeller to a rotating drive shaft on a boat such that the entire propeller rotates with the drive shaft;
- a plurality of blades extending radially outwardly from the hub case and comprising a hydrodynamic surface and a retainer shaft means extending axially from the hydrodynamic surface and being pivotally secured to the hub case such that each blade is mounted to the hub case for pivotal movement about a blade axis between two extreme angular pitch positions:
- a first locked angular position defining a lower pitch position, and second angular position defining a high pitch position;
- pitch shifting means comprising a mass member operably secured to the retainer shaft means and designed to cause the blade to pivot from one angular position to the other angular position in response to the reaction force generated upon rotation of the propeller;
- positive locking means comprising a locking member operably connected between the hub case and the retainer shaft means for preventing pivoting of the blade in response to the pitch shifting means when the blades are in the first locked angular position;
- and release means comprising a second mass member operably engaging the locking member and designed to move in response to the rotation of the propeller at a minimum threshold rotation velocity so as to release the locking means and to permit the pitch shifting mass to cause the pivoting of the blades.
A variable pitch marine propeller comprising a hub case;
- drive securing means designed to secure the propeller to a rotating drive shaft on a boat, such that the propeller rotates with the drive shaft;
- a plurality of blades extending radially outwardly form the hub case, a blade shaft secured to each blade and extending radially inwardly of, and journalled to, the hub case, such that each blade is mounted to the hub case for pivotal movement, characterized by each blade being pivotable between two locked angular positions, a first locked angular position defining a lowest pitch position and a second locked angular position defining a highest pitch position;
- a moment arm member secured to each blade shaft and extending within the hub case substantially perpendicular to the blade shaft;
- a counter-weight secured to an end portion of each moment arm member in a position such that rotation of the propeller generates a turning moment on the blade shaft tending to turn the blade towards a higher pitch position;
- a two-position affirmative locking means operatively connected to the moment arm member for preventing pivoting movement of the moment arm member so as to secure the blade to one of the two locked angular positions;
- release means comprising actuating means and a release member, the actuating means comprising a mass member pivotally secured to the hub case so as to generate in reaction to the propeller being rotated a minimum threshold rotational velocity, and the release member being operably connected between the actuating means and the locking means, such that movement of the release member in response to the actuating member releases the locking means, thus permitting movement of the moment arm and pivoting of the blade to the second locked position and movement of the locking means from one locked position towards the second locked position.
Dependencies are inferred from the claim text.