Torque releasing clutch mechanism and motor control

Claim 1

A FLUID-POWERED WRENCH ADAPTED TO RELEASE ITS DRIVING TORQUE AND SHUT OFF ITS MOTOR IN RESPONSE TO A PREDETERMINED TORQUE LOAD, SAID WRENCH COMPRISING: (A) A BODY CONTAINING A FLUID MOTOR AND A SPINDLE FOR DRIVING FASTENERS; (B) A CLUTCH INTERCONNECTED BETWEEN SAID MOTOR AND SPINDLE ADAPTED TO RELEASE ITSELF IN RESPONSE TO A PREDETERMINED TORQUE, SAID CLUTCH INCLUDING A MEMBER ADAPTED TO MOVE AXIALLY REARWARD WHEN SAID CLUTCH RELEASES; (C) A VALVE LOCATED IN A PASSAGE FEEDING PRESSURE FLUID TO SAID MOTOR AND ADAPTED TO CLOSE SAID PASSAGE TO SHUT OFF SAID MOTOR, SAID VALVE BEING MOUNTED IN THE REAR OF SAID BODY AND ARRANGED TO MOVE REARWARDLY AS IT CLOSES, SAID VALVE INCLUDING FIRST SPRING MEANS ENGAGING IT AND URGING IT TO AN OPEN POSITION; (D) LINKAGE MEANS INTERCONNECTED BETWEEN SAID VALVE AND SAID AXIALLY MOVABLE CLUTCH MEMBER ADAPTED TO FORCE SAID VALVE REARWARDLY TOWARD ITS CLOSED POSITION AS SAID CLUTCH OPENS; (E) SAID VALVE INCLUDING MEANS FOR UTILIZING FLUID PRESSURE TO CLOSE IT COMPLETELY AFTER IT IS PARTLY CLOSED BY SAID LINKAGE MEANS DURING THE RELEASE OF SAID CLUTCH; AND (F) SECOND SPRING MEANS FOR NORMALLY URGING SAID CLUTCH MEMBER AXIALLY IN A DIRECTION RELEASING SAID CLUTCH, SAID SECOND SPRING MEANS ACTING IN A DIRECTION OPPOSITE TO AND BEING WEAKER THAN SAID FIRST SPRING MEANS URGING SAID VALVE TO AN OPEN POSITION, SAID SECOND SPRING MEANS BEING OPERATIVE TO FORCE SAID CLUTCH MEMBER REARWARDLY TO ITS CLUTCH RELEASING POSITION AFTER SAID VALVE IS CLOSED BY FLUID PRESSURE.