Rotary vane-type pump structure

Claim 1

IN AN IMPELLER UNIT FOR A ROTARY VANE-TYPE DISPLACEMENT PUMP HAVING A PUMP DRIVE SHAFT ROTATABLY MOUNTED GENERALLY ECCENTRICALLY WITHIN A PUMP HOUSING, (A) A SUPPORTING HUB CARRIED BY THE SHAFT AND ROTATING THEREWITH, SAID HUB HAVING A PLURALITY OF VANE SOCKETS CIRCUMFERENTIALLY DISTRIBUTED ABOUT THE HUB, AND (B) VANES OF A RESILIENT FLEXIBLE MATERIAL HAVING ATTACHMENT BASES SECURED ONE EACH WITHIN THE SOCKETS AND EXTENDING OUTWARDLY INTO ENGAGEMENT WITH THE PUMP HOUSING, (C) THE HUB HAVING RESTRICTED OPENINGS TO THE SOCKETS THROUGH WHICH THE VANES PROJECT WITH THE OPENINGS BEING EACH DEFINED BY A DEFLECTION CONTROL SURFACE ON THE HUB EXTENDING AS A CONTINUOUS SMOOTH CURVED SURFACE OF INCREASING RADIUS FOR A SUBSTANTIAL PORTION OF THE HUB BETWEEN THE ADJACENT SOCKETS IMMEDIATELY ADJACENT THE BASE OF THE CORRESPONDING VANE, AND THE ECCENTRICITY OF THE PUMP HOUSING RELATIVE TO THE PATH OF THE VANE SERVING TO FLEX SAID VANES SUCCESSIVELY INTO CONTACT WITH THE CORRESPONDING CONTROL SURFACES BEGINNING AT THE RESTRICTED OPENING AND MOVING OUTWARDLY AS SAID HUB ROTATES AND SAID VANES MOVE FROM THE MAXIMUM SPACING TO THE MINIMUM SPACING BETWEEN THE HUB AND THE WALL OF THE PUMP HOUSING.