Well apparatus setting tool

Claim 1

A WELL APPARATUS SETTING TOOL HAVING AN UPPER END AND A LOWER END AND COMPRISING A PLURALITY OF COAXIAL SERIALLY CONNECTED CYLINDERS DISPOSED WITH THEIR AXES VERTICAL WITH RESPECT TO SAID TOOL, A PLURALITY OF PISTONS DISPOSED ONE IN EACH OF SAID CYLINDERS, EACH PISTON HAVING A PASSAGE THERETHROUGH FROM ITS UPPER PART TO ITS LOWER PART, HOLLOW PISTON RODS SERIALLY CONNECTING SAID PISTONS AND SAID PASSAGES THERETHROUGH, THE UPPERMOST OF SAID CYLINDERS BEING ADAPTED FOR CONNECTION TO A SOURCE OF PRESSURE FLUID, MEANS SEALING BETWEEN EACH PISTON ROD AND THE ADJACENT CYLINDER, SAID PISTON RODS INCLUDING PASSAGES CONNECTING THE INTERIORS OF THE HOLLOW PISTON RODS TO THE SPACES BELOW THE PISTONS INSIDE THE SEVERAL CYLINDERS, THERE BEING A VENT TO THE SPACE ABOVE EACH PISTON INSIDE THE SEVERAL CYLINDERS WHEREBY ANY FLUID IN THE CYLINDER ABOVE THE PISTON CAN ESCAPE SO THAT THE PISTON IS FREE TO MOVE UPWARDLY SO FAR AS SUCH FLUID IS CONCERNED, SAID VENTS BEING DISPOSED JUST BELOW SAID SEALING MEANS, THERE BEING AN ADDITIONAL VENT TO THE SPACE INSIDE THE LOWERMOST CYLINDER, THE LAST SAID VENT BEING SPACED BELOW THE FIRST MENTIONED VENT FOR THE LAST SAID SPACE A DISTANCE GREATER THAN THE HEIGHT OF THE LOWERMOST PISTON, THE LAST SAID VENT PROVIDING A PASSAGE FOR THE ESCAPE OF FLUID THROUGH THE LAST SAID SPACE FROM THE LOWERMOST PISTON ROD WHEN THE LOWERMOST PISTON IS DISPOSED ABOVE SAID ADDITIONAL VENT, AND MEANS CONNECTED TO THE LOWERMOST PISTON AND CYLINDER FOR CONNECTION TO A DEVICE TO BE ACTUATED BY RELATIVE MOVEMENT BETWEEN SAID LOWERMOST PISTON AND CYLINDER.