Rotary fluid machines

Claim 1

ROTARY FLUID ENGINE COMPRISING A CASING, A ROTOR MOUNTED WITHIN SAID CASING AND HAVING SIDE WALLS EXTENDING AXIALLY AND RADIALLY OUTWARDLY BEYOND SAID CASING TO FORM END CLOSURE FOR SAID CASING, SAID CASING ON THE ONE HAND AND SAID ROTOR AND SIDE WALLS ON THE OTHER HAND BEING ARRANGED FOR RELATIVE ROTATION WITH RESPECT TO EACH OTHER, SAID ROTOR HAVING RADIAL SLOTS, VANES IN SAID SLOTS HAVING EXTENSIONS IN SAID SIDE WALLS PROVIDED WITH BEARING SURFACES IN SAID SLOTS AT SAID SIDE WALLS, ONE OF SAID BEARING SURFACES OF A VANE EXTENSION IN A CORRESPONDING SIDE WALL HAVING A COUNTERBALANCING RECESS TO RECEIVE PRESSURE FLUID, AND A PASSAGE LEADING FROM SAID RECESS TO THE FACE OF THE CORRESPONDING VANE WITHIN SAID CASING OPPOSITE SUCH RECESS, SUCH RECESS BEING DISPOSED RADIALLY IN SAID VANE EXTENSION SUCH THAT THE CENTER OF PRESSURE OF SAID RECESS IS SUBSTANTIALLY WITHIN THE RADIAL LIMITS OF THE CENTER PORTION OF THE VANE EXPOSED TO FLUID PRESSURE.