Rotary impact hammer

Claim 1

IN COMBINATION WITH A PORTABLE ELECTRIC DRILL OF THE TYPE HAVING A CASE AND A DRIVE SHAFT PROTRUDING THEREFROM, A ROTARY IMPACT HAMMER, COMPRISING, AN ELONGATED HOLLOW HOUSING MOUNTED ON THE CASE AT THE DRIVE SHAFT; A SPINDLE JOURNALED IN THE HOUSING FOR ROTARY AND LIMITED AXIAL MOVEMENT RELATIVE TO THE HOUSING AND EXTENDING THROUGH THE FORWARD END THEREOF; COUPLING MEANS ON SAID SPINDLE WITHIN SAID HOUSING FOR CONNECTION TO THE MOTOR DRIVE SHAFT; ANVIL MEANS COMPRISING A SHOULDERED COLLAR POSITIONED ON THE SPINDLE INTERMEDIATE ITS ENDS; HAMMER MEANS SLIDABLY MOUNTED ON AND KEYED TO THE SPINDLE FOR ROTATION THEREWITH AND MOVEMENT AXIALLY THEREOF BETWEEN A FIRST POSITION, IN ENGAGEMENT WITH THE SPINDLE ANVIL, AND A SECOND POSITION, SPACED FROM THE ANVIL; SPRING MEANS MOUNTED ON THE SPINDLE IN PRESSED ENGAGEMENT WITH THE HAMMER FOR NORMALLY BIASING THE HAMMER TO ITS FIRST POSITION; AND COOPERATING CAM MEANS ON SAID HAMMER AND HOUSING FOR ALTERNATELY MOVING THE HAMMER BETWEEN ITS FIRST AND SECOND POSITIONS FOR IMPARTING IMPACT TO THE SPINDLE ANVIL ALONG ITS AXIS OF ROTATION WHEN THE SPINDLE IS ROTATED IN THE HOUSING, SAID COOPERATING CAM MEANS COMPRISING A PLURALITY OF CIRCUMFERENTIALLY ARRANGED CAMMING PORTIONS ON AN END FACE OF THE HAMMER, AND ROTATING THEREWITH, AND A PLURALITY OF COOPERATING CIRCULARLY ARRANGED CAMMING PORTIONS ON THE HOUSING AND HELD STATIONARY THEREBY.