Drag bit

Claim 1

A ROTARY DRAG BIT COMPRISING: A HOLLOW BIT BODY INCLUDING AN UPPER BODY SECTION PROVIDED WITH MEANS FOR CONNECTING SAID BODY TO THE LOWER END OF A ROTARY DRILL STRING AND AN ENLARGED LOWER BODY SECTION CONTAINING CIRCUMFERENTIALLYSPACED FLOW CHANNELS OF STREAMLINED CROSS SECTION EXTENDING LONGITUDINALLY IN THE OUTER SURFACE THEREOF TO PERMIT THE PASSAGE OF DRILLING FLUID UPWARDLY FROM BENEATH SAID LOWER SECTION INTO THE SPACE SURROUNDING SAID UPPER SECTION; A PLURALITY OF ELONGATED BLADES ATTACHED TO AND DEPENDING FROM SAID LOWER BODY SECTION AT INTERMEDIATE POSITIONS BETWEEN SAID FLOW CHANNELS, THE OUTERMOST SURFACE OF SAID LOWER BODY SECTION ADJACENT EACH BLADE EXTENDING CIRCUMFERENTIALLY IN FRONT OF SAID BLADE TO A FLOW CHANNEL AND BEHIND SAID BLADE TO A FLOW CHANNEL AND EACH OF SAID BLADES INCLUDING A FACE EXTENDING LATERALLY IN A SUBSTANTIALLY RADIAL DIRECTION FROM A POINT NEAR THE LONGITUDINAL AXIS OF SAID LOWER BODY SECTION TO A POINT ADJACENT THE OUTER SURFACE OF SAID LOWER BODY SECTION; AND NOZZLES LOCATED IN SAID LOWER BODY SECTION BETWEEN THE FACES OF SAID BLADES AND THE ADJACENT FLOW CHANNELS NEAR THE PERIPHERY OF SAID LOWER BODY SECTION, EACH OF SAID NOZZLES COMMUNICATING WITH THE INTERIOR OF SAID BODY AND BEING ORIENTED TO DIRECT A STREAM OF DRILLING FLUID DOWNWARDLY TOWARD A POINT NEAR THE LOWER GAGE CORNER OF A BLADE.