Safety stop for the traveling block of drilling rigs

Claim 1

A SAFETY STOP MECHANISM FOR SELECTIVELY STOPPING THE ROTATION OF A POWER DRIVEN WINDING DRUM WHICH IS MOUNTED ON A SHAFT, A FRAME MOUNTING THE SHAFT OF SAID WINDING DRUM FOR ROTATION IN EITHER DIRECTION, A FLUID ACTUATED CLUTCH MOUNTED ON THE SHAFT OF SAID WINDING DRUM, A FLUID ACTUATED BRAKE MOUNTED ON SAID FRAME AND BEING CONNECTED IN BRAKING RELATION WITH SAID WINDING DRUM, SAID SAFETY STOP MECHANISM COMPRISING A GEAR REDUCTION UNIT MOUNTED ON SAID FRAME, MEANS OPERATIVELY CONNECTING SAID GEAR REDUCTION UNIT IN DRIVEN RELATION OUTTHE SHAFT OF SAID WINDING DRUM, A SHAFT EXTENDING OUTWARDLY FROM A SIDE OF SAID GEAR REDUCTION UNIT, A CAM DISC MOUNTED ON SAID SHAFT EXTENDING OUTWARDLY FROM SAID GEAR REDUCTION UNIT, A CAM OF EFFECTIVE, ADJUSTABLE LENGTH OF AT LEAST 30* OF ARCUATE LENGTH OPERABLY MOUNTED ON SAID CAM DISC AND BEING ROTATABLE THEREWITH ABOUT THE AXIS OF SAID SHAFT AND IN UNISON THEREWITH, A FIRST VALVE ACTUATOR PIVOTALLY MOUNTED ON SAID GEAR REDUCTION UNIT, A CAM FOLLOWER MOUNTED ON SAID FIRST VALVE ACTUATOR AND BEING ACTUATED BY SAID CAM ON SAID CAM DISC WHEN SAID SHAFT IS ROTATED, A FIRST FLUID VALVE MOUNTED ON SUPPLY FLUID UNDER PRESSURE, A FIRST VALVE MOUNTED ON SAID GEAR REDUCTION UNIT AND CONNECTED IN FLUID COMMUNICATION WITH SAID FIRST FLUID SUPPLY CONDUIT, SAID FIRST VALVE BEING OPERATED BY SAID FIRST VALVE ACTUATOR UPON MOVEMENT OF SAID CAM, A SECOND VALVE ACTUATOR, SAID SECOND VALVE ACTUATOR BEING OPERABLE BY FLUID PRESSURE FROM SAID FLUID ACTUATOR CONDUIT, A FLUID CONDUIT VALVE ACTUATHE OUTLET OF SAID FIRST VALVE AND SAID SECOND VALVE ACTUATOR IN FLUID COMMUNICATION, A SECOND VALVE, SAID SECOND VALVE BEING CONNECTED IN ACTUATING RELATION WITH SAID SECOND VALVE ACTUATOR, A SECOND FLUID SUPPLY CONDUIT CONNECTED TO SAID SECOND VALVE, BRANCH CONDUITS LEADING FROM SAID SECOND VALVE, ONE OF SAID BRANCH CONDUITS BEING CONNECTED WITH THE FLUID ACTUATED CLUTCH, THE OTHER OF SAID BRANCH CONDUITS BEING CONNECTED WITH THE FLUID ACTUATED BRAKE, SO THE FLUID ACTUATED CLUTCH AND THE FLUID ACTUATED BRAKE RESPECTIVELY WILL BE ACTUATED SIMULTANEOUSLY, BUT INVERSELY, UPON MOVEMENT OF SAID SECOND VALVE BY SAID SECOND VALVE ACTUATOR IN SYNCHRONOUS RELATION TO THE CAM ACTUATED FIRST VALVE TO DIRECT FLUID FROM SAID FLUID ACTUATED CLUTCH AND TO DIRECT FLUID UNDER PRESSURE TO SAID FLUID ACTUATED BRAKE RESPECTIVELY TO STOP THE ROTATION OF SAID WINDING DRUM.