A chain drive for moving a closure element of a building opening, especially a window, a skylight, a door or a smoke extraction flap and/or an aeration and/or venting flap, with a) a housing, elongated in a longitudinal direction respectively with two lateral and front walls as well as a bottom and a ceiling wall, b) a power transmission chain with a rigid back, a chain having spaced straps, connected by bolts, leaving an intermediate space transversale to a longitudinal extension of the power transmission chain, c) a drive unit (7, 8) arranged in the housing, d) a chain sprocket which can be driven by a drive unit (7, 8) and co-operates with the power transmission chain for the longitudinal transfer thereof, e) an exit opening running through the housing wall for the power transmission chain, out of which protrudes a first outer chain end of the power transmission chain, f) a chain station provided in the housing, for receiving the power transmission chain in a retracted state, in three receiving sections (20, 21, 22) transversal to the longitudinal direction, substantially parallel to each other in the direction from one lateral wall to the other lateral wall seen as piled up over one another, extending respectively parallel to the longitudinal direction, sections divided in a first receiving station closest to the exit opening, a section which is an outer receiving section directed towards to a first of the lateral walls, a second receiving section, overlapping the first receiving section and provides an outer receiving section directed towards the second lateral wall, and a third receiving section, which is a middle receiving section arranged between the first receiving section and the second receiving section, wherein a first diverting section is provided at a first front side of the chain station, for transferring the power transmission chain between the first receiving section and the second receiving section by diverting the same by substantially 180° and, a second diverting section for transferring the power transmission chain is provided at a second front side, opposite the first front side of the power transmission chain, between the second receiving section and the third receiving section by diverting the same by substantially 180°, characterised in that the second receiving section and the third receiving section of the chain station are separated by a thin wall stucture made of sheet-metal, protuding transversally to the bottom or ceiling wall of the housing and transversally to the longitudinal direction of the power transmission chain into the inside of the housing, a structure extending along at least one portion of the boundary between the second receiving section and the third receiving section in the longitudinal direction of the housing, wherein the second receiving section and the third receiving section of the chain station are connected to each other immediately at the respective side of the sheet-metal wall structure facing the same and wherein a free-standing edge of the wall structure is provided in the area of the second diverting section and there guides the straps of the power transmission chain to its side opposite the back of the chain, when the power transmission chain is transferred and diverted from the third receiving section into the second receiving section. a) a housing, elongated in a longitudinal direction respectively with two lateral and front walls as well as a bottom and a ceiling wall, b) a power transmission chain with a rigid back, a chain having spaced straps, connected by bolts, leaving an intermediate space transversale to a longitudinal extension of the power transmission chain, c) a drive unit (7, 8) arranged in the housing, d) a chain sprocket which can be driven by a drive unit (7, 8) and co-operates with the power transmission chain for the longitudinal transfer thereof, e) an exit opening running through the housing wall for the power transmission chain, out of which protrudes a first outer chain end of the power transmission chain, f) a chain station provided in the housing, for receiving the power transmission chain in a retracted state, in three receiving sections (20, 21, 22) transversal to the longitudinal direction, substantially parallel to each other in the direction from one lateral wall to the other lateral wall seen as piled up over one another, extending respectively parallel to the longitudinal direction, sections divided in a first receiving station closest to the exit opening, a section which is an outer receiving section directed towards to a first of the lateral walls, a second receiving section, overlapping the first receiving section and provides an outer receiving section directed towards the second lateral wall, and a third receiving section, which is a middle receiving section arranged between the first receiving section and the second receiving section, wherein a first diverting section is provided at a first front side of the chain station, for transferring the power transmission chain between the first receiving section and the second receiving section by diverting the same by substantially 180° and, a second diverting section for transferring the power transmission chain is provided at a second front side, opposite the first front side of the power transmission chain, between the second receiving section and the third receiving section by diverting the same by substantially 180°,