Variable-pitch blade propeller

Claim 1

AN ADJUSTABLE PITCH PROPELLER HAVING A HOLLOW DRIVE SHAFT AND A HUB CASING MOUNTED AT THE END OF THE DRIVE SHAFT, SAID CASING HAVING A SUBSTANTIALLY SQUARE CROSS SECTION, A PROPELLER BLADE EXTENDING RADIALLY FROM EACH SIDE OF SAID CASING AND HAVING A FLAT CIRCULAR BASE OF MAXIMUM DIAMETER ROTATABLY MOUNTED ON THE CORRESPONDING SIDE OF SIDE CASING, A MOUNTING SHAFT EXTENDING FROM EACH CIRCULAR BASE THROUGH A BEARING IN SAID CASING AND HAVING AN ARCUATE RACK OR GEAR PORTION ON ONE SIDE AT THE INNER END OF SAID MOUNTING SHAFT AND AN ARCUATE GUIDE SURFACE ON THE OPPOSITE SIDE THEREOF, AN AXIALLY MOVABLE YOKE MEMBER FORMING A YOKE STRADDLING EACH MOUNTING SHAFT IN SAID CASING, EACH YOKE COMPRISING A PAIR OF AXIALLY EXTENDING LEGS SLIDABLY MOUNTED IN ANGULAR RECESSES AT THE INSIDE CORNERS OF SAID SQUARE CASING AND HAVING OPPOSING RACK AND FLAT GUIDE SURFACES COACTING WITH THE ARCUATE RACK PORTION AND ARCUATE GUIDE SURFACE RESPECTIVELY ON THE END OF THE CORRESPONDING MOUNTING SHAFT FOR SIMULTANEOUS ADJUSTMENT OF ALL THE BLADES, EACH LEG OF EACH YOKE SERVING ALSO AS THE ADJACENT LEG OF THE ADJACENT YOKE TO FORM A COMPACT YOKE MEMBER REENFORCED AGAINST DISTORTION BY THE SIDES OF SAID CORNER RECESSES, SUBSTANTIALLY CONICALLY STREAMLINED END PORTIONS FORE AND AFT OF SAID CASING, THE FORWARD END PORTION BEING STREAMLINED INTO THE AFT END OF SAID HOLLOW DRIVE SHAFT, A CONTROL ROD EXTENDING FREELY THROUGH SAID HOLLOW SHAFT IN SPACED RELATION THERETO,F AND CONNECTED TO SAID YOKE MEMBER FOR CONTROLLING SAID ADJUSTMENT OF ALL THE BLADES FROM THE FORWARD END OF SAID HOLLOW DRIVE SHAFT, SAID ROD HAVING A SUBSTANTIALLY SMALLER DIAMETER THAN THE INTERNAL DIAMETER OF SAID HOLLOW SHAFT, AND THE BASE OF EACH BLADE HAVING AN OVERHANGING CIRCUMFERENTIAL FLANGE FORMING A SUBSTANTIALLY CLOSED BALL BEARING OUTER RACE AND THE HUB CASING HAVING A RAISED CIRCULAR STEP TO FORM A BALL BEARING INNER RACE AND BALL BEARINGS COACTING WITH SAID RACES.