Cutter blade and screen for lawn mower mulching attachment

Claim 1

IN COMBINATION WITH A ROTARY POWER LAWN MOWER OF THE TYPE INCLUDING A HOUSING HAVING A GENERALLY HORIZONTAL TOP WALL WITH A PERIPHERAL SKIRT DEPENDING THEREFROM AND DEFINING THEREWITH A DOWNWARDLY OPENING MOWING CHAMBER, SAID SKIRT INCLUDING A LATERAL OUTLET FOR THE DISCHARGE OF GRASS CUTTINGS FROM SAID MOWING CHAMBER, SAID HOUSING HAVING A POWER SOURCE MOUNTED THEREON AND INCLUDING A DEPENDING ROTATABLE POWER SHAFT PROJECTING DOWNWARDLY THROUGH SAID TOP WALL INTO SAID CHAMBER, A BLADE MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH AND DISPOSED WITHIN SAID CHAMBER, A MULCHER COMPRISING AN UPSTANDING DRUMSHAPED MEMBER DISPOSED ENTIRELY WITHIN SAID CHAMBER AND INCLUDING UPSTANDING GENERALLY CYLINDRICAL SIDE WALLS, A GENERALLY HORIZONTAL TOP WALL EXTENDING BETWEEN THE UPPER EDGE PORTIONS OF SAID SIDEWALLS AND HAVING AN OPENING THEREIN DOWN THROUGH WHICH SAID SHAFT PROJECTS, AN ANNULAR INWARDLY PROJECTING BOTTOM WALL SECURED BETWEEN THE LOWER EDGE PORTIONS OF SAID SIDE WALLS, FASTENING MEANS REMOVABLY SECURING THE SECOND MENTIONED TOP WALL TO THE UNDERSURFACE OF SAID FIRST-MENTIONED TOP WALL, SAID CYLINDRICAL SIDE WALL HAVING AN OPENING FORMED THEREIN REGISTERED WITH SAID LATERAL OUTLET, A DRUM-SHAPED MULCHING SCREEN CONCENTRICALLY DISPOSED WITHIN SAID DRUMSHAPED MEMBER AND INCLUDING UPSTANDING GENERALLY CYLINDRICAL SIDE WALLS OF A DIAMETER GREATER THAN THE INNER DIAMETER OF THE BOTTOM WALL AND SMALLER THAN THE DIAMETER OF THE FIRST-MENTIONED CYLINDRICAL SIDE WALLS, SAID MULCHING SCREEN INCLUDING AN ANNULAR TOP WALL THROUGH WHICH SAID FASTENERS ARE ALSO SECURED TO FASTEN SAID ANNULAR TOP WALL TO THE UNDERSURFACE OF THE SECOND-MENTIONED TOP WALL, THE LAST-MENTIONED SIDE WALL EXTENDING THE FULL DISTANCE BETWEEN SAID SECOND-MENTIONED TOP WALL AND SAID ANNULAR BOTTOM WALL AND BEING ABUTTED AGAINST THE LATER, THE LAST-MENTIONED SIDE WALL INCLUDING A PLURALITY OF OPENINGS FORMED THEREIN AND SPACED CIRCUMFERENTIALLY THEREABOUT AND HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED PORTIONS THEREOF LATERALLY STRUCK INWARDLY THEREFROM DEFINING INWARDLY PROJECTING LUGS, AT LEAST SOME OF SAID OPENINGS BEING FORMED BY THE INWARD DISPLACEMENT OF THE FREE END OF SAID LUGS, SAID BLADE BEING ELONGATED AND INCLUDING OPPOSITE END PORTIONS WHICH ARE INCLINED RELATIVE TO THE PLANE IN WHICH SAID BLADE IS ROTATABLE, SAID END PORTIONS INCLUDING INTERNAL ENDS DISPOSED FOR SWINGING IN CLOSE PROXIMITY TO THE INNER ENDS OF SAID LEGS UPON ROTATION OF SAID SHAFT.