Oy Wartsila Ab

Sven-Eric Johansson

The invention relates to a method, and to an arrangement, for optimizing the operation of a door closer at different phases of opening and closing of the door. The door closer is provided with a force transmission shaft (1) turning in accordance with the movements of the door and with a spring element (2) operationally connected thereto. The opening of the door takes place against the force of the spring element (2). According to the invention, at the closing phase of the door the energy of the spring element (2), exceeding the return force of the spring element (2) needed to accomplish the desired closing movement of the door, is recovered through simultaneous braking of the closing movement of the door for the main part of the closing movement. When the door is only somewhat open any more, preferably under 5.degree., a final force securing the closing of the door is accomplished by making use of said recovered energy. For putting the method into practice, the door closer is provided with rotor (4), stator (5) and energy storing device (7), arranged to serve as an electric generator or as an electric motor as required.

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Torshalla, Sweden

Sven-Eric Johansson