Expansible rotary drill bit

Claim 1

AN EXPANSIBLE ROTARY BIT FOR OPERATION UPON THE FORMATONS IN WELL BORES TO ENLARGE THE WELL BORES INCLUDING, A BODY HAVING AN AXIAL BORE EXTENDING ENTIRELY THERETHROUGH AND HAVING A PLURALITY OF LONGITUDINAL SLOTS IN THE LOWER PORTION OF ITS WALL WHICH SLOTS ARE SPACED CIRCUMFERENTIALLY AROUND THE BODY, A PLURALITY OF CUTTER-SUPPORTING ARMS PIVOTALLY MOUNTED ON SAID BODY, EACH ARM BEING MOVABLE THROUGH ONE OF THE SLOTS IN A GENERALLY RADIAL DIRECTION WITH RESPECT TO THE BODY, A CUTTER CARRIED BY THE LOWER PORTION OF EACH ARM, A PISTON ASSEMBLY MOUNTED WITHIN THE BORE OF THE BODY AND MOVABLE LONGITUDINALLY THEREIN WITHIN LIMITS WITH RESPECT TO THE BODY AND TO THE CUTTER-SUPPORTING ARMS, A CONNECTING LINK MEMBER FOR EACH CUTTER-SUPPORTING ARM HAVING ONE END PIVOTALY CONNECTED TO SAID ARM AND ITS OPPOSITE END PIVOTALLY CONNECTED TO THE PISTON ASSEMBLY, WHEREBY MOVEMENT OF SAID PISTON ASSEMBLY DOWNWARDLY RELATIVE TO THE BODY AND CUTTER-SUPPORTING ARMS IMPARTS GENERALLY RADIAL OUTWARD MOVEMENT TO SAID ARMS AND THE CUTTERS CARRIED THEREBY, ERACH ARM HAVING ONE SURFACE THEREOF IN CONTACT WITH ONE WALL OF THE SLOT IN WHICH IT IS MOVABLE TO PROVIDE A ROTATIVE CONNECTION BETWEEN THE BODY AND EACH ARM, AND A DRIVE LUG ON THE INNER SIDE OF EACH ARM FORMING AN EXTENSION OF THAT SURFACE OF THE ARM WHICH ENGAGES THE WALL OF ITS RESPECTIVE SLOT, SAID LUG ALSO ENGAGING THE WALL OF THE SLOT TO PROVIDE ROTATIVE CONNECTION BETWEEN THE BODY AND ARM WHEN THE ARM IS AT ITS OUTERMOST RADIAL POSITION RELATIVE TO THE BODY.