Variable area turbine nozzle for axial flow gas turbine engines

Claim 1

IN AN AXIAL FLOW GAS TURBINE, A VARIABLE AREA TURBINE NOZZLE COMPRISING: WALL MEANS DEFINING AN ANNULAR FLUID FLOW PASSAGEWAY THROUGH WHICH HIGH TEMPERATURE MOTIVE FLUID IS SUPPILED TO SAID TURBINE, A PLURALITY OF CIRCUMFERENTIALLY SPACED RADIALLY EXTENDING VANES TRAVERSING SAID PASSAGEWAY WITH THE ENDS OF THE VANES IN PROXIMITY TO SAID WALL MEANS, EACH OF SAID VANES HAVING A CONCAVE SIDE WALL AND A CONVEX SIDE WALL CONNECTING AXIALLY SPACED LEADING AND TRAILING EDGE PORTIONS TO FORM AN AIRFOIL SHAPED CROSS SECTION, THE CIRCUMFERENTIAL SPACING BETWEEN ADJACENT ONES OF SAID VANES BEING SUBSTANTIALLY LESS THAN THE CHORD LENGTH OF SAID VANES, A PLURALITY OF CIRCULAR PLATFORMS HAVING RADIALLY EXTENDING CENTERS OF REVOLUTION, EACH END OF EACH OF SAID VANES HAVING ONE OF SAID CIRCULAR PLATFORMS SECURED THERETO ADJACENT AND LIMITED TO THE TRAILING EDGE PORTION OF THE ASSOCIATED VANE, PORTIONS OF THE ENDS OF SAID VANES EXTENDING ACROSS DIAMETRAL PORTIONS OF SAID CIRCULAR PLATFORMS, A PLURALITY OF CIRCULAR RECESSES IN SAID WALL MEANS, EACH OF SAID RECESSES RECEIVING A RESPECTIVE ONE OF SAID CIRCULAR PLATFORMS FOR LOCATION THEREIN, AND ACTUATING MEANS CONNECTED TO EACH OF SAID VANES FOR PIVOTING SAID VANES ABOUT THE CENTERS OF REVOLUTION OF SAID CIRCULAR PLATFORMS TO VARY THE FLOW AREAS BETWEEN ADJACENT ONES OF SAID VANES, WHEREBY EFFECTIVE SHROUDING IS PROVIDED FOR PREVENTING LEAKAGE BETWEEN THE CONCAVE AND CONVEX SIDES OF THE VANES IN THE HIGH PRESSURE GRADIENT REGION ADJACENT THE TRAILING EDGE PORTIONS.