Fluid-operated cylinder-piston unit, and a tool provided therewith

摘要

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.