Abstract: A pneumatic actuating drive (1, 61) for final control elements comprises a drive housing (6) and a drive component (15) movable therein, to which the drive component (15) is attached a drive element (24) that exits from the drive housing (6) and that can be moved together with the drive component (15), and which has the function of actuating the actuator (1, 61) and which divides the drive housing (6) into a pressure chamber (16) and a reset chamber (17) with a reset element (19, 20) that acts on the drive component (15). The actuating drive (1, 61) furthermore comprises a position controller (41) whose output (48) merges into an internal supply duct (49), which is connected to a transfer connection (35, 62) on the reset chamber side on the drive element (24), whereby the drive element (24) exhibits an air duct (30), which originates from the transfer connection (35, 62) and merges into the air duct (30).

Abstract: A pneumatic control drive 1, 51, 71 for control devices, in particular control valves, comprises a drive housing 5 and a drive member 11 displaceable therein and to which is affixed a drive element 18 displaceable together with said drive member 11 to actuate the control device and exiting the drive housing 5, said drive member dividing the drive housing 5 into a pressure chamber 12 and a reset chamber 13 with a reset member 15, 16 loading the drive member 11. A position controller 3 is adjacent to one of the chambers (13) and communicates through an inner air-supply duct 30, 28, 55, 74 with the pressure chamber 12, a vent duct 35, 58, 76 issuing from the reset chamber 13 toward a vent aperture. In the invention, the drive element 18 comprises an air-supply duct 24, 25 issuing at the side of the drive member 11 away from the position controller 3 into the pressure chamber 12 there.