Lubrication of fan blade bearings

In combination with an axial flow fan having a housing, at least one rotor disposed within said housing and secured to a rotatable drive shaft formed with a center bore, a control shaft extending through the bore in spaced relation to the drive shaft, wall means defining a cavity within said rotor, blades mounted on the rotor, each of said blades being adapted to be angularly shifted about its central axis and including being fitted with a shank extending through a peripheral section of said wall means, bearing means interposed between said shank and peripheral wall section, a hydraulic device for shifting said blades, and wherein the control and drive shafts and the hydraulic device define a means for conveying a fluid lubricant into said cavity, the conveying means including the hydraulic device having an inlet and an outlet chamber, a fixed open ended tubular member interposed between and communicating with said inlet and outlet chambers, the outlet chamber having a perforated wall, and the control and drive shafts being formed with passages communicating with the center bore and with the rotor cavity and through the perforated wall with said outlet chamber, and valved conduit means connecting the inlet chamber with a source for supplying lubricant through the conveying means to said cavity, said lubricant being centrifugally displaced during rotation of the rotor to form a fluid layer against said peripheral wall section thereby providing a continuous supply of lubricant for said bearing means.