{"id":14921,"date":"2026-10-06T14:31:15","date_gmt":"2026-10-06T13:31:15","guid":{"rendered":"https:\/\/ventsystems.de\/?p=14921"},"modified":"2026-10-09T07:36:40","modified_gmt":"2026-10-09T06:36:40","slug":"chain-actuator-roof-windows","status":"publish","type":"post","link":"https:\/\/ventsystems.de\/en\/kettenantrieb-dachfenster\/","title":{"rendered":"Chain actuator for roof windows"},"content":{"rendered":"

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Technical specification and use of chain drives on roof windows<\/h2>\n

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Using electric chain drives on roof windows and skylights places higher demands on drive technology than vertically installed fa\u00e7ade windows. This is mainly due to the changed kinematics and the static loads caused by the roof pitch and external environmental factors. Chain drives automate ventilation processes (natural ventilation) and ensure smoke extraction openings in smoke and heat exhaust ventilation systems (SHEV).<\/p>\n

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Building physics and structural characteristics<\/h2>\n

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Unlike turn-and-tilt windows in the fa\u00e7ade, where the drive essentially has to overcome the friction of the fittings and the sash weight along a vertical axis, different force vectors act on roof windows.<\/p>\n

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Load bearing and snow load<\/h3>\n

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A chain drive on a roof window must lift the entire sash weight against gravity. In addition, the push force (N)<\/strong> of the drive must be dimensioned so that it can also handle external loads. These include in particular snow load in winter and wind load (suction and pressure). While 200 N to 300 N are often sufficient for a fa\u00e7ade window, roof window drives often require push forces of 400 N up to 1000 N, depending on the area and glass weight.<\/p>\n

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Tight closing and wind tightness<\/h3>\n

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Due to the exposed position on the roof, the contact pressure in the closed state is critical. The drive must have sufficient Holding force<\/strong> to compress the window seals enough to keep out driving rain and wind. If the locking force of the drive is too low, this can lead to moisture damage in the roof structure.<\/p>\n

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Function and design<\/h2>\n

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Chain drives use a special back-stiff chain that bends in one direction (for winding into the housing) but remains rigid in the other (push direction).<\/p>\n

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Geometric adjustment with brackets<\/h3>\n

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As roof windows are usually designed as top-hung or pivot sashes, the angle between the window frame and the sash changes significantly during opening. A rigidly mounted drive would create mechanical stresses that damage the chain or the mounting point. Therefore, mounting with swivel brackets<\/strong> is therefore essential. They allow the drive body to follow the movement of the window and keep the exit angle of the chain in line with the point of force application.<\/p>\n

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Stroke lengths and opening width<\/h3>\n

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The stroke length (usually between 250 mm and 800 mm) determines the geometric free cross-section of the opening.<\/p>\n

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