GB575268A - Screw propeller, particularly for aircraft - Google Patents

Abstract

575,268. Screw propellers. REISSNER, H. Dec. 7, 1943, No. 20466. [Class 114] The pitch of the blades of a propeller is varied automatically under the influence of centrifugal force, torque and thrust, each blade 15 being supported on the hub by an axis disposed at a small angle to the centroid axis, the axis being supported by a bearing 18 and by an outer shell 24 slidably embracing a hemispherical shell 21 rotating with the shaft, the shell 24 having a socket containing a ring 26 eccentric to the axis, this ring having opposed tongues slidable in grooves in the shell 21. The shell 21 carries a bevel wheel 22 driven from a gear wheel 39 on the hub through differential gearing comprising a fixed pinion and a pinion 43 mounted on a ring movable by a rack 50. The orientation of the slots can thus be adjusted to vary the equilibrium conditions. Alternatively, the shell may be driven from the hub through an elastic connection which may be held in abnormal position by a brake to give orientation suitable for reversed thrust position. A counter-rotating propeller assembly may be used, with differential pitch-adjusting gear common to the two shells 21, and an idler gear conveying counter-rotation. A worm may replace the rack 50, its linear movement effecting rapid major adjustments and its rotary movement slower minor changes. Specification 499,932 is referred to.