Cutterhead assembly for a shield-type tunneling machine

Claim 1

IN A CUTTERHEAD ASSEMBLY FOR AN EARTH BORING MACHINE; A REVERSIBLE CUTTERHEAD, CUTTERHEAD SUPPORT MEANS MOUNTING SAID CUTTERHEAD FOR ROTATION ABOUT A CENTER AXIS, REVERSIBLE DRIVE MEANS FOR SELECTIVELY ROTATING THE CUTTERHEAD IN EITHER DIRECTION ABOUT SAID AXIS, AND MEANS FOR MOVING THE CUTTERHEAD ASSEMBLY AXIALLY FORWARDLY INTO AN EARTH FORMATION, SAID CUTTERHEAD COMPRISING A FORWARD WALL, FORWARDLY DIRECTED CUTTER MEANS ON SAID WALL FOR CUTTING AND DISLODGING THE EARTH FORMATION DURING CUTTERHEAD ROTATION, IN EITHER DIRECTION, AT LEAST ONE PERIPHERAL BUCKET HAVING AN AXIALLY FORWARDLY DIRECTED INLET OPENING AND A SCOOP WHICH OPENS IN ONE DIRECTION OF CUTTERHEAD ROTATION, AND SCOOPS UP EARTH FORMATION CUTTINGS DURING CUTTERHEAD ROTATION IN SUCH DIRECTION, AT LEAST ONE OTHER PERIPHERAL BUCKET HAVING AN AXIALLY FORWARDLY DIRECTED INLET OPENING AND A SCOOP WHICH OPENS IN THE OPPOSITE DIRECTION OF CUTTERHEAD ROTATION, AND SCOOPS UP EARTH FORMATION CUTTINGS DURING CUTTERHEAD ROTATION IN SUCH DIRECTION, EACH SAID SCOOP OCCUPYING A FIXED POSITION ON THE CUTTERHEAD AND INCLUDING WALL MEANS FOR TURNING AND DIRECTING THE SCOOPED EARTH FORMATION CUTTINGS GENERALLY RADIALLY INWARDLY, AND AN ELONGATED MATERIAL CHUTE EXTENDING GENERALLY RADIALLY INWARDLY FROM EACH SAID BUCKET.