U.S. Patent Specifications

In a hub for airplane or similar propellers having a plurality of blades, sleeves integral with the hub adapted to receive the spindles of the blades so as to permit their turning about their longitudinal axes for the variation of pitch, a holding member for the spindle of each blade, a sliding member mounted on the hub in axial sliding relation thereto, means connecting the holding member to said sliding member, a means adapted to displace said sliding member, gearings operated by the rotation of the hub for actuating said displacing means a coupling included in said gearings comprising two ratchet‐wheels having oppositely directed teeth and pawls adapted to be engaged by centrifugal action, and means intermediate said coupling and the blades to cause the automatic disengagement of one of said pawls from its ratchet wheels through the movement of the blades upon the latter reaching the end positions of their angular displacement.