An expansion device for drum brakes, which is floatingly and approximately centrally arranged between two substantially symmetrical brake shoes, the expansion device including at least two gear levers articulated to each other and each supported on a brake shoe, at least one of the gear levers of the expansion lock being coupled to an actuating element of an actuator system such that the brake shoes carry out an even, translationally directed expanding movement, which is converted by a gearing, in the direction of the brake drum. At least one of the gear levers of the spreader lock has a spring element integrated into it that can be elastically reversibly deformed by a brake application force about a defined elasticity ΔS of at least 1 mm in a defined manner.