Variable-pitch propeller having feathering blades

A variable pitch-propeller having feathering blades, comprising:

• a hub fitted on a drive shaft of a propulsory means;
• a shell rotatably embracing the hub, said shell having a front annular shell half and a rear annular shell half axially fixed to each other;
• propeller blades mounted rotatably about their own axes through respective holes defined by the shell;
• a bevel toothing provided on the hub and meshing with bevel pinions carried by each of said propeller blades;
• an adjusting element rotatably engaged on the hub;
• a first circular sector connected to and projecting outwardly from the hub;
• a second circular sector projecting inwardly from the adjusting element and designed to engage the first circular sector to transmit a rotatory motion from the hub to the shell;
• a gear coupling having mating toothings carried respectively by the rear shell half and the adjusting element and meshing together to couple the shell and the adjusting element;
• axial securing screws housed in slots of circular outline formed in said adjusting element and engaging the rear shell half by threaded portions to lock axial movement of the adjusting element, said screws having a longitudinal dimension greater than the longitudinal dimension of said mating toothings, and wherein said axial axial screws may be loosened to allow reciprocal disengagement of the mating toothings and rotation of the adjusting element with respect to the shell.

A process for modifying the pitch of a variable-pitch propeller having a shell embracing rotatably a hub fitted on a drive shaft, and adjusting element rotatably engaged on the hub and coupled with the shell by a gear coupling having mating toothings carried respectively by a rear shell and the adjusting element, and axial securing screws housed in slots of circular outline formed in the adjusting element, said process comprising the steps of:

• loosening the securing screws;
• axially shifting said adjusting element until said toothings are disengaged from each other;
• rotating said adjusting element through a desired angle:
• moving said adjusting element in the opposite way relative to the shifting step bringing said toothings again into mutual engagement;
• and tightening again said securing screws.