Patent ID: 7252018

Claim:
A drive for closure elements, comprising a reference value generator arranged in or on gearing ( 14 , 12 , 10 ) of the drive for determining the actual position of the closure element, the reference value generator having two reference discs ( 18 , 20 ) offset with respect to one another and thereby rotating at different angular speeds, which, in predetermined angular positions to one another, define the reference point positions which can be scanned by at least one scanning device ( 22 ), said reference discs ( 18 , 20 ) overlapping at least once during respective rotation, each said reference disc ( 18 , 20 ) comprising at least one signal mark ( 26 , 28 ), and said signal marks ( 26 , 28 ) overlapping at least once during rotation of said respective reference discs ( 18 , 20 ), such that said overlapping is detected by said scanning device ( 22 ).