| 摘要 |
The door actuator comprises a spindle drive having a spindle (1) connected to a freewheel allowing rotation of the spindle in the direction corresponding to the closing direction of the door and preventing rotation of the spindle in the direction corresponding to the opening direction. The part of the freewheel furthest from the spindle is mounted so that it rotates but is releasably fixed relative to a release device (2) by a coupling, brake, etc. released by a solenoid (8) against the force of at least one pressure spring (5). The brake, coupling, etc. is/can be fixed in its open position. A closing magnet is provided. The closing magnet is designed as a double-acting lifting magnet. In the released position a moving part (gear (3)) consisting of ferromagnetic material moves so close to at least one permanent magnet that its forces of attraction exceed the force of the pressure spring. |
