Abstract: For tightening threaded connectors, a plurality of fluid-operated torque tools are used, each engaging with a respective of one threaded connector. It is sensed when at least one of the fluid-operated torque tools reaches a point during an advance stroke when it permits a return ratcheting, and automatically all pistons of all fluid-operated torque tools are retracted even if a rest of the pistons or the fluid-operated torque tools are not advanced to a point when the return ratcheting of the tools is permitted.

Abstract: A fluid-operated tool for tightening and loosening threaded connectors has a ratchet unit including a ratchet connectable with a threaded connector to be tightened and loosened and provided with a plurality of teeth, and a pawl engageable in and disengageable from the teeth of the ratchet, a drive connected with the ratchet and movable over an advance stroke to turn the ratchet when the pawl engages the teeth of the ratchet so as to turn a threaded connector connected with the ratchet for tightening or loosening, and a retract stroke in which the pawl is disengaged from the teeth of the ratchet, and a unit for sensing when the pawl falls into engagement with a tooth of the ratchet and in response reversing the drive from the retract stroke to the advance stroke.

Abstract: A fluid-operated cylinder-piston unit has a cylinder forming an inner space, a piston unit movable in the inner space and including a first piston and a second piston movable relative to one another and each having a displacement area at one end and a force applying area at another opposite end. The pistons are arranged so as to form a smaller displacement area associated with one of the pistons and a larger displacement area associated with both of the pistons. A fluid supply to the piston unit is performed so that first only one of the pistons moves and another of the pistons remains stationary during an advance stroke, and during a return stroke fluid has to be applied only to the displacement area of the one piston, while thereafter another of the pistons is moved as well under the action of fluid and both pistons move to apply a larger force due the larger total displacement area and during a return stroke fluid is applied to the larger displacement area.