An amphibious vehicle for traversing land and bodies of water includes a chassis, and a cycloidal propeller coupled to the chassis and which includes a plurality of cycloidal propeller blades rotatably coupled to the chassis and each extending parallel a rotational axis of the cycloidal propeller, and an extension/retraction system configured to extend the plurality of cycloidal propeller blades away from the chassis and to retract the plurality of cycloidal propeller blades towards the chassis.

An amphibious vehicle for traversing land and bodies of water includes a chassis, and a cycloidal propeller coupled to the chassis and which includes a plurality of cycloidal propeller blades rotatably coupled to the chassis and each extending parallel a rotational axis of the cycloidal propeller, and an extension/retraction system configured to extend the plurality of cycloidal propeller blades away from the chassis and to retract the plurality of cycloidal propeller blades towards the chassis.

A propeller pitch adjustment assembly is provided with a base hub operatively connected by blade shafts to propeller blades in which each blade rotates about an axis of each shaft. Each blade shaft is radially disposed about a propeller drive shaft and parallel to a pressure flange of a base hub spring plate. The spring plate counterforces the blade rotation with a lever screw that impacts the plate. An opposing spring transfers a load to the plate. The equilibrium position of the plate is determined by the spring force on the lever and a counteracting force exerted on the lever by a lift force generated by fluid flow over a propeller blade. A capping mechanism can provide a preload to the spring. A force exerted by the lift of the blade on the lever screw results in a blade pitch change.

A bistable pitch propeller includes a ball, a spring, and a clutch module where the clutch module has a range of rotational movement between a locked end position and a released end position. The clutch module includes a detent, where the ball sits inside and outside of the detent when the clutch module is in the locked end position and released end position, respectively. In response to an input torque and a spring force from the spring, the clutch module rotates toward the released end position and the locked end position, respectively. The bistable pitch propeller also includes an aircraft blade where the aircraft blade is at the first pitch angle and the second pitch angle when the clutch module is in the locked end position and the released end position, respectively.

A system and method for blade angle position feedback. The system comprises an feedback device and a sensor mounted adjacent the feedback device and configured for detecting a passage of position markers on the feedback device during propeller rotation. The position markers are spaced apart from one another around the circumference of the feedback device and are oriented at an angle to one another and to a longitudinal axis. The feedback device and sensor are configured for relative axial displacement. A detection unit is connected to the sensor for receiving the sensor signal therefrom, determining on the basis of the sensor signal a time interval elapsed between the passage of successive position markers, and computing from the time interval blade angle position.

A propeller (1) and a respective use method are described, comprising a cylindrical casing (3), a hub (2) couplable to an engine and rotatably mounted at least partially in the cylindrical casing of the propeller, and at least one blade (4) rotatably pivoted to the cylindrical casing. The hub (2) is rotatable with respect to the cylindrical casing of the propeller, or vice versa, to adjust the fluid dynamic pitch of the at least one blade (4). The propeller further comprises at least one elastic element (8) interposed between the hub (2) and the cylindrical casing (3) and it is characterized in that the elastic element (8) is preloaded to prevent its deformation until the resistant torque opposing the propeller rotation is lower than the torque generated by the preload of the elastic element (8), wherein said at least one blade is arranged on at least one first fixed fluid dynamic pitch before the deformation of the elastic element (8) begins. It is further described a flat spring (100) for propellers, which has a longitudinal development line (MS) and comprises a plurality of notches (103) transversally arranged with respect to the longitudinal development line. At least two distances (MD) between successive notches (103) are different from one another and/or at least two notches (103) are different from one another.

The invention concerns a hydraulic adjusting device (1, 35) having at least two leakage paths (24, 25) which are connected by a transition channel (27), a sealing arrangement (18) which leads back to a working chamber (10) being provided in one of the leakage paths (24, 25) in delimiting manner relative to the working chamber (10) of the adjusting device (35).

The invention concerns a hydraulic adjusting device (1, 35) having at least two leakage paths (24, 25) which are connected by a transition channel (27), a sealing arrangement (18) which leads back to a working chamber (10) being provided in one of the leakage paths (24, 25) in delimiting manner relative to the working chamber (10) of the adjusting device (35).

A propeller and related method for adjusting the fluid-dynamic pitch of the propeller blades are described. The propeller has at least one rotatable blade pivoted to a propeller cylindrical casing, a hub adapted to be coupled to an engine and mounted within the propeller casing. The hub is rotatable with respect to the propeller cylindrical casing, or vice versa, for a non-zero angular interval () for the adjustment of the fluid-dynamic blade pitch. Moreover, the hub has a contact surface movable between direct or indirect disengagement and engagement positions with a respective abutment which defines a limit stop of the angular interval (). The limit stop abutment has a region of a movable element arranged in a seat of the propeller cylindrical casing for modifying the limit stop abutment position of the at least one angular interval ().

A propeller and related method for adjusting the fluid-dynamic pitch of the propeller blades are described. The propeller has at least one rotatable blade pivoted to a propeller cylindrical casing, a hub adapted to be coupled to an engine and mounted within the propeller casing. The hub is rotatable with respect to the propeller cylindrical casing, or vice versa, for a non-zero angular interval () for the adjustment of the fluid-dynamic blade pitch. Moreover, the hub has a contact surface movable between direct or indirect disengagement and engagement positions with a respective abutment which defines a limit stop of the angular interval (). The limit stop abutment has a region of a movable element arranged in a seat of the propeller cylindrical casing for modifying the limit stop abutment position of the at least one angular interval ().