Piston door damperED STD3

For hinged lift doors of the makes Thyssen/Stahl and Otis The DICTATOR ED STD3 hinged door damper is designed for the final damping of hinged landing doors being closed by a spring. The damper is installed in the door frame and is accessible through the lift shaft. The piston rod of the damper points through the door frame and makes contact with the side of the closing door where the hinges are fixed. To protect the sheet steel on the door leaf from wear, a special hardened counter plate for the piston rod needs to be fixed to the point where the piston rod meets the door. For Otis lift doors this counter plate is round, for all other lift doors it is rectangular. The ED STD3 damper works hydraulically. Its special feature is the oil tank on top which is connected to the damping cylinder. This guarantees that the ED STD3 slows down and effectively damps the door as soon as it hits the piston. If the cylinder consisted only of a simple tube, air in the cylinder could reduce the damping considerably as there is only a damping distance of 20 mm. Highest performance and a long operational life of the damper are achieved by a tempered guide for the piston rod in the damper and a set of special seals. A scraper ring of polyurethane prevents the soiling of the guiding and sealing elements.