The drive shaft K is mounted behind the Hammer R. In the first position when the point D is located in the upper half of the vertical diameter of R, the hammer is inclined to the left and the hammer J is just about to take the valve rod P. In the second position of the point D is on the left side of the horizontal diameter of the wheel R. The valve rod is touched by the hammer J, not just pushed all the way down, the valve is open. In the fourth position, D is removed from the hammer axis A. The drive rod has the hammer on the side of the valve out T, which is open in the fourth position already.