Quick access/adjustment piston

An hydraulic piston-cylinder assembly configured within a press machine enables adjustments to be made to the shutheight parameter through changes in the positioning of the bed in accordance with hydraulic pressure variations in the piston-cylinder assembly. The cylinder device, which is arranged to be reversibly movable with respect to the piston device under the influence of the pressure variations, is coupled to the bed such that movements of the cylinder device induce a corresponding displacement of the bed, thereby changing the shutheight. The piston device is characterized by a property of tensile elasticity in at least one dimension thereof substantially coincident with the shutheight dimension. Accordingly, in one operating mode, there may be effectuated a reversible displacement of the cylinder device beyond its established range-of-motion by changing the hydraulic pressurization of the piston-cylinder assembly in a manner sufficient to induce an elastic tensile effect in the piston device.