Electric drive unit for the corner steady of a trailer vehicle

An overload protection in a drive unit for a steady or jack for a caravan is constituted by an electro-mechanical control system. The support leg (3) is actuated by a spindle (7) driven by a motor (13) through a gearbox (15). The motor (13) is controlled through the power supply (50) connected by an electric circuit (51). A control device in the system comprises a movable part (28) slidably seated on an output shaft (30) of the gearbox (15), where the movable part (28) is connected with the spindle (7). Movement between the shaft (30) and the sliding part (28) is counteracted by springs (34, 35). The slidable part (28) is provided with extending actuating points (42) that may contact switches (44, 45) by axial movements of the part (28). When a nut (9) on the spindle (7) reaches an end position, a reactive force in the spindle (7) will cause the part (28) to move against the force of springs (34, 35), eventually actuating a switch (44 or 45) and thereby causing interruption of the circuit (51). The motor (13) and the engagement between nut (9) and spindle (7) are thereby protected from electric and mechanical overload, respectively.