Hydraulic cylinder for downcoiler having bearing and damping features

PURPOSE: A hydraulic cylinder for a downcoiler having properties of a dynamic bearing and a damper is provided to minimize the friction between a piston member and the outer circumference of a cylinder and to have a damping effect when the piston member reciprocates inside the cylinder. CONSTITUTION: A hydraulic cylinder for a downcoiler comprises a cylinder(10), inlet/outlet ports(14), a piston member(20), check valves(30), orifices(31), and protrusion portions(40) The cylinder has first and second piston sheets(11,12) where an inner hole(13) is punched. The inlet/outlet ports are respectively formed in both sides of the outer circumference of the cylinder. The piston member longitudinally reciprocates between the first and second piston sheets. The check valves and orifices are embedded in the first and second piston sheets to serve as a damper when the piston member longitudinally reciprocates. The protrusion portions fix the position of the piston member when the piston member laterally reciprocates.