Hydraulic pop riveters

Claim 1

IN A RIVET SETTING TOOL FOR THE PULLING OF BLIND RIVETS AND THE LIKE WHICH CONTAIN A MANDREL MEMBER TO BE BROKEN AT THE COMPLETION OF THE RIVET SETTING OPERATION, SAID TOOL HAVING A FLUID SUPPLY CYLINDER AND PISTON ASSEMBLY, A DRAW CYLINDER CONNECTED TO THE FLUID SUPPLY CYLINDER, A DRAW ROD SLIDABLY DISPOSED IN THE DRAW CYLINDER HAVING RIVET GRIPPING MEANS ON ONE END AND A PISTON ON THE OTHER END, A CONDUIT EXTENDING FROM THE FLUID SUPPLY CYLINDER TO THE DRAW CYLINDER, AND MEANS FOR FORCING FLUID FROM THE SUPPLY CYLINDER TO THE DRAW CYLINDER TO INITIATE A WORKING STROKE OF SAID TOOL, THAT IMPROVEMENT COMPRISING MEANS FOR PREVENTING RECOIL ACTION OF SAID TOOL, SAID LAST MEANS INCLUDING METERING MEANS DISPOSED IN SAID CONDUIT AND RESPONSIVE TO THE FLOW OF THE FLUID FROM THE FLUID CYLINDER TO THE DRAW CYLINDER TO RESTRICT SAID FLOW DURING SAID WORKING STROKE, WHEREBY SAID RESTRICTED FLOW OF FLUID PREVENTS RECOIL ACTION BY RETARDING EXCESSIVE TRAVEL OF SAID PISTON WHEN THE MANDREL OF THE RIVET IS BROKEN.