Fluid actuated impact tool

Claim 1

AN IMPACT TOOL POWERED BY A COMPRESSIBLE FLUID WHICH COMPRISES IN COMBINATION A HOUSING; AN INLET FOR ACTUATING FLUID INTO THE HOUSING; AN ANVIL MOUNTED IN THE HOUSING FOR LIMITED RECIPROCATING MOVEMENT; A HAMMER MOUNTED BETWEEN THE INLET AND ANVIL AND RECIPROCABLE IN THE HOUSING TO BEAT UPON THE ANVIL, SAID HAMMER HAVING ENDWISE SURFACES OF DIFFERENT AREAS AGAINST WHICH PRESSURE FROM FLUID IN THE HOUSING CAN ACT TO URGE THE HAMMER IN POWER AND RETURN STROKES; A FIRST FLUID PASSAGEWAY THROUGH THE HAMMER EXTENDING BETWEEN SAID SURFACES; A SECOND FLUID PASSAGEWAY THROUGH THE ANVIL EXTENDING FROM A SURFACE OF THE ANVIL OPPOSED TO THE HAMMER TO THE EXTERIOR OF THE TOOL; A FIRST VALVE CLOSURE MEMBER, CARRIED BY THE HOUSING, DISPOSED TO OPEN AND CLOSE SAID FIRST PASSAGEWAY AFTER FINITE MOVEMENT OF THE HAMMER IN POWER AND RETURN STROKES, RESPECTIVELY; A SECOND VALVE CLOSURE MEMBER, CARRIED BY THE HAMMER, DISPOSED TO CLOSE AND OPEN SAID SECOND PASSAGEWAY AFTER FINITE MOVEMENT OF THE HAMMER IN POWER AND RETURN STROKES, RESPECTIVELY, SAID VALVE CLOSURE ELEMENTS BEING COOPERABLE TO APPLY PRESSURE FROM FLUID IN THE HOUSING ALTERNATELY TO SAID ENDWISE SURFACES OF THE HAMMER AND TOO REDUCE PRESSURE ON THE ENDWISE SURFACE OPPOSITE TO THE ONE UPON WHICH PRESSURE IS APPLIED; AND A CHECK VALVE BIASED AGAINST INLET PRESSURE DISVERSE FLOW OF ACTUATING FLUID INTO THE INLET, SAID CHECK VALVE, HOUSING, HAMMER AND FIRST VALVE CLOSURE MEMBER BEING COOPERABLE TO PROVIDE A CLOSED SMALL VOLUME CHAMBER IN THE HOUSING WHEN SAID FIRST PASSAGEWAY IS CLOSED BY SAID FIRST VALVE CLOSURE MEMBER.