Impact drill

Claim 1

AN IMPACT DRILL, COMPRISING IN COMBINATION, AN ELECTRIC MOTOR, INCLUDING A DRIVE SHAFT, MOUNTED IN A CASE HAVING A HAND GRIP; A SPINDLE HOUSING MOUNTED ON THE CASE AT THE DRIVE SHAFT; A SPINDLE MOUNTED ON THE END OF THE DRIVE SHAFT, FORMING A CONTINUATION THEREOF, AND EXTENDING THROUGH THE HOUSING; TOOL HOLDING MEANS MOUNTED ON THE FREE END OF THE SPINDLE, BEYOND THE HOUSING; A CYLINDRICAL ANVIL CO-AXIALLY MOUNTED ON THE SPINDLE, WITHIN THE HOUSING, AND ROTATABLE THEREWITH; THE ANVIL HAVING A PLURALITY OF BORES THERETHROUGH, SPACED FROM AND PARALLEL TO THE AXIS OF THE SPINDLE, EACH OF SAID BORES BEING COUNTER-BORED TO DEFINE AN ANVIL SEAT AT THE INNER END OF EACH COUNTER-BORE; A CYLINDRICAL HAMMER SLIDABLY MOUNTED IN EACH OF SAID COUNTER-BORES, FREELY MOVABLE LONGITUDINALLY OF SAID COUNTER-BORES TOWARD AND AWAY FROM THEIR RESPECTIVE ANVIL SEATS; A PRESSURE WASHER MOUNTED ON THE SPINDLE, AGAINST THE ANVIL, AND COVERING THE OUTER ENDS OF THE COUNTER-BORES; SPRING MEANS MOUNTED IN EACH COUNTER-BORE, BETWEEN THE WASHER AND HAMMER, FOR NORMALLY BIASING EACH HAMMER TO A FIRST POSITION, WHEREIN IT BEARS AGAINST THE ANVIL SEAT THEREOF; A CAM-FOLLOWER MOUNTED IN EACH OF THE ANVIL BORES, OF A LENGTH SUCH THAT IT WILL CONTACT THE HAMMER AND PROTRUDE BEYOND THE END OF THE ANVIL, WHEN THE HAMMER IS IN ITS FIRST POSITION; AND A STATIONARY CAM MOUNTED ON THE HOUSING, IN CO-AXIAL RELATION WITH SAID ROTATING SPINDLE, OPPOSED TO AND SPACED FROM THE CIRCULAR TRAVEL PATH OF THE ANVIL BORES, HAVING AN INTERRUPTED CAM SURFACE ENGAGEABLE WITH THE CAM-FOLLOWERS PROTRUDING FROM THE ROTATING ANVIL, WHEN THE HAMMERS ARE IN THEIR FIRST POSITIONS, TO PUSH THE HAMMERS LONGITUDINALLY OF THE ANVIL COUNTER-BORES, AGAINST THE BIASING ACTION OF THE SPRINGS, TO A SECOND POSITION, SPACED FROM THE ANVIL SEATS; THE HAMMERS BEING RETURNED TO THEIR FIRST POSITIONS, BY THE SPRING, WHEN ENGAGEMENT BETWEEN THE CAM AND CAM-FOLLOWERS IS INTERRUPTED AS THE CAM-FOLLOWERS ARE MOVED RELATIVE TO THE CAM SURFACES BY THE ROTATION OF THE ANVIL.