Impact absorbing blade mounts for variable pitch blades
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsRichard Ravenhall, Charles T. Salemme, Arthur P. Adamson
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Abstract
A variable pitch blade and blade mount which is suitable for propellers, fans and the like and which has improved impact resistance. The invention is particularly directed to composite fan blades and blade mounting arrangements wherein the blades are permitted to pivot relative to a turbine hub about an axis generally parallel to the centerline of the engine upon impact of a large foreign object, such as a bird. By thus providing for the pivoting of the blades upon impact, centrifugal force recovery becomes the principal energy absorbing mechanism and a blade having improved impact strength is obtained.
Claims21
A blade mount for a variable pitch blade including a blade root, said blade mount comprising:
- a. a jaw having opposing sides defining a cross-sectional shape corresponding to that of the blade root, said jaw being open on at least one end for slideably receiving said blade root, and providing for the pivoting of the blade about an axis for absorbing impact energy, and
- b. a tie bar interconnecting said jaw opposing sides to resist the expansion of said jaw during centrifugal loading.
An improved blade retaining apparatus for connecting a variable pitch blade to a rotatable hub, wherein the improvement comprises:
- a. a shank attached to said hub and extending substantially radially outwardly therefrom;
- b. means for rotating said shank on its longitudinal axis;
- and
- c. a jaw connected at its one end to the end of said shank and comprising a pair of oppositely disposed arms defining an enlarged slot for receiving a blade root and retaining it from movement in the radially outward direction.
Dependencies are inferred from the claim text.