1. IN APPARATUS FOR TENSIONING A MOVING WIRE ROD, A SUPPORT, A BASE PLATE MOUNTED ON SAID SUPPORT, A HOUSING STRUCTURE ROTATABLY SUPPORTED ON SAID BASE PLATE, SAID HOUSING STRUCTURE BEING CONSTRUCTED AND ARRANGED TO PROVIDE A RESERVOIR CHAMBER, MEANS CONNECTED BETWEEN SAID HOUSING STRUCTURE AND SAID SUPPORT FOR YIELDABLY RESTRAINING SAID HOUSING STRUCTURE AGAINST ROTATION AND FOR GIVING A SENSIBLE INDICATION OF THE TORQUE EXERTED BY THE HOUSING STRUCTURE, A SHEAVE ROTATABLY MOUNTED ON SAID HOUSING STRUCTURE, A PUMP MOUNTED IN SAID HOUSING STRUCTURE, A DRIVING CONNECTION BETWEEN SAID PUMP AND SAID SHEAVE, INTAKE CONDUIT MEANS LEADING FROM SAID RESERVOIR CHAMBER TO SAID PUMP, OUTLET CONDUIT MEANS LEADING FROM SAID PUMP TO SAID RESERVOIR CHAMBER, AND MEANS FOR ADJUSTABLY RESTRICTING FLOW OF FLUID THROUGH SAID OUTLET CONDUIT MEANS.