Abstract: A cylindrical chamber full of oil, without any valves or inlet/exit ports for this oil. A piston travels in said sealed cylindrical chamber with a rod on either side, assembled with sealing rings and provided with a series of peripheral axial holes all of the same diameter and equidistant from the piston axis. On the rod anchored to the ram slides a plunger disc supported directly under the piston assembly by two diametrically opposed threaded studs with large heads. Said studs are first threaded through the piston assembly and then screwed through the two holes found on the plunger disc. The upward travel of this disc which stops under and against the piston holes, is prevented each time the dual push-button control is operated since, when operating, these buttons, besides starting the movement of the ram, prevents the upward travel of the plunger disc simultaneously.