Rock drilling mechanisms

Claim 1

A ROCK DRILLING MECHANISM COMPRISING A HAND GUIDED AND DIRECTED DRILLING TOOL, SAID TOOL HAVING A PRESSURE FLUID OPERATED MOTOR FOR ACTUATING A DRILLING IMPLEMENT, A HANDLE MOUNTED AT THE REAR END OF THE TOOL WHICH IS GRASPED BY THE OPERATOR IN THE GUIDING AND DIRECTING OF THE TOOL, A PRESSURE FLUID OPERATED FEED LEG ADAPTED TO REST AT ITS LOWER END UPON THE FLOOR, AND COMPRISING RELATIVELY RECIPROCABLE FLUID CYLINDER AND PISTON ELEMENTS PROVIDING BETWEEN THEM AN EXPANSIVE CHAMBER, SAID CYLINDER ELEMENT PROJECTING UPWARDLY ABOVE SAID PISTON ELEMENT, A CYLINDER HEAD CARRIED BY SAID CYLINDER ELEMENT AT ONE END OF SAID EXPANSION CHAMBER IN SAID CYLINDER ELEMENT AT ONE END OF SAID PISTON ELEMENT, A FEED LEG CONTRACTION CHAMBER IN SAID CYLINDER ELEMENT AT THE OPPOSITE END OF SAID PISTON ELEMENT, A TRUNNION AND A COOPERATING BEARING ON SAID TOOL PROVIDING A TRANSVERSE HINGE CONNECTION BETWEEN THE UPPER END OF THE CYLINDER ELEMENT AND SAID DRILLING TOOL TO PERMIT TILTING OF SAID TOOL AND FEED LEG IN UPRIGHT PLANES IN DIFFERENT ANGULAR POSITIONS WITH RESPECT TO EACH OTHER, AT LEAST TWO CIRCUMFERENTIAL GROOVES IN SAID TRUNNION, PASSAGES IN SAID TOOL COMMUNICATING WITH SAID GROOVES, A FIRST PASSAGE IN THE TRUNNION AND IN THE CYLINDER HEAD AND FORMING COMMUNICATION BETWEEN ONE OF SAID GROOVES AND SAID EXPANSION CHAMBER, A SECOND PASSAGE IN THE TRUNNION AND IN THE CYLINDER FORMING COMMUNICATION BETWEEN ANOTHER OF SAID GROOVES AND SAID CONTRACTION CHAMBER, MEANS FOR ATTACHING SAID TRUNNION TO SAID CYLINDER HEAD, FLUID SUPPLY MEANS LEADING TO THE TOOL, CONTROL VALVE MEANS FOR CONTROLLING THE SUPPLY OF OPERATING FLUID THROUGH SAID PASSAGES FROM SAID FLUID SUPPLY MEANS TO SAID OPERATING CHAMBERS IN THE FEED LEG FOR PRODUCING EXPANSION OR CONTRACTION OF THE FEED LEG, RESPECTIVELY, AND MEANS LOCATED AT THE REAR END OF THE TOOL ADJACENT TO SAID HANDLE FOR VENTING PRESSURE FLUID FROM SAID FEED LEG EXPANSION CHAMBER.