Abstract: The invention relates to a drive (1) for a movable element, with which the element is brought from an initial position into a second position, an opening and closing position in particular. The drive (1) has a housing (2), at least one spring element (9) arranged in the housing (2), at least one spring supporting member (6) at which the spring element is supported (9), and at least one roller element (19, 20, 26, 27) arranged at the spring supporting member. The task of the invention is therefore to simplify the design of the known drive in order to facilitate assembly and reduce the manufacturing and assembly costs. According to the invention the spring supporting member (6) of the drive (1) has at least one curved surface (18, 25), and the roller element (19, 20, 26, 27) is arranged at the curved surface (18, 25).

Abstract: The power wrench is provided with a coupling (14), switching dependent on the rotational moment and switching between a fast run mode and a load mode, when the rotational moment of the output exceeds a limit value. A distributing shaft (23) simulaneously drives two drive gears (26, 27). The output shaft (28) is pulled by a coupling member (32) that may be engaged to any one of said drive gears (26, 27). The coupling member (32) is prestressed by a spring (38) towards said first drive gear. At reaching the limit moment, the guiding member (40) shifts along the guide surface (39). This causes an axial movement of the coupling member (32) to disengage from said first drive gear (26) and to engage with said second drive gear (27).