Flow control valve for jet type bits

Claim 1

IN A DRILL BIT HAVING A BODY, A PLURALITY OF CUTTER MEANS JOURNALLED ON SAID BODY, A RECESS IN SAID BODY FORMING UPPER AND LOWER CHAMBERS, A PLURALITY OF JET PASSAGEWAYS EXTENDING THERETHROUGH INTERSECTING SAID UPPER CHAMBER AND ORITENTED TO DIRECT A JET OF AIR BETWEEN ADJACENT CUTTER MEANS, AND A COOLING PASSAGEWAY EXTENDING THERETHROUGH FOR EACH OF SAID CUTTER MEANS INTERSECTING SAID LOWER CHAMBER AND ARRANGED TO DISCHARGE AIR INTO THE JOURNALS FOR SAID CUTTER MEANS, THE IMPROVEMENT COMPRISING: FLOW CONTROL MEANS LOCATED IN THE UPPER CHAMBER OF SAID RECESS RELATIVELY ABOVE THE INTERSECTIONS OF SAID JET PASSAGEWAYS WITH SAID UPPER CHAMBER, SAID FLOW CONTROL MEANS INCLUDING MEANS FOR SUBSTANTIALLY PREVENTING FLOW FROM SAID JET PASSAGEWAYS THERETHROUGH WHILE PERMITTING FLOW IN THE OPPOSITE DIRECTION; AND A HOLLOW MEMBER LOCATED IN SAID RECESS AND EXTENDING THROUGH SAID FLOW CONTROL MEANS, SAID HOLLOW MEMBER HAVING AN OPEN LOWER END LOCATED IN SAID LOWER CHAMBER IN COMMUNICATION WITH SAID COOLING PASSAGEWAYS AND A PERFORATED UPPER END PORTION ABOVE SAID FLOW CONTROL MEANS.