in which the movement of a door leaf 8 8 u2032 is prevented for example as a result of trapped persons or objects in a position which does not correspond to the closed position the connecting link 14 also prevents the locking axle or shaft 10 from pivoting and the resulting reaction torque which corresponds to the motor torque can for example be used to detect an incidence of persons or objects being trapped the locking device and the arrangement of the drive for twin leaf doors in a region of a main closing edge has a functional advantage and also an advantage that the important and relatively bulky components are provided at a point of the doorway or portal that is most accessible and where there is the greatest availability of space this facilitates inspections adjustments and repairs the embodiment of fig1 and 2 shows a sliding door it is possible to use the locking device or arrangement according to the present disclosure with swing and sliding doors in which the drive serves both to guide the door leaves 8 8 u2032 longitudinally and to impart a swinging out movement out of the plane of the portal a brake 17 or the like can be provided on the locking transmission 4 the brake may be engaged at a very beginning of the opening movement so that the swinging out movement takes place as a result of the reaction torque on the motor housing 2 a whereupon the brake is released the locking action is.