A pneumatic spring brake cylinder is provided for brake systems of vehicles, including a housing in which a spring brake piston loaded by an accumulator spring and connected to a spring brake piston tube is guided in a movable manner, and an emergency release device for the emergency release of the spring brake piston in the event of a drop in pressure. The emergency release device contains a spindle which can be rotated relative to the spring brake cylinder and which can be screwed in a nut that is held in a rotationally fixed manner in the spring brake piston tube by a form-fitting connection. The nut interacts with an axial stop on the spring brake piston in order to trigger a release movement against the effect of the accumulator spring. The formfitting connection is formed between an outer polygonal profiled section of the outer circumference of the nut in a circumferential direction and a complementary circumferential inner polygonal profiled section on the inner circumference of an intermediate bushing and between an outer polygonal profiled section of the outer circumference of the intermediate bushing in the circumferential direction and a complementary circumferential inner polygonal profiled section on the inner circumference of the spring brake piston tube.