of the spring 12 enables also compensation of an angular error of the seat 5 of the closing elements 41 42 43 or an angular deviation between closing elements 41 42 43 and follower pin 11 according to fig4 c and 4 d play is provided only at the guide bearing 132 that is farthest removed from the cam 6 i e positioned opposite the cam relative to the closing elements 4 fig4 c shows an annular linear contact between the follower pin 11 and the guide bearings 131 that is closest to the cam 6 according to fig4 d the follower pin 11 is provided with a spherical bearing 14 at the guide bearing 131 that is closest to the cam 6 these configurations enable also compensation of an alignment deviation of the follower pin 11 or a bad orientation of the seat 5 of a closing element 41 42 43 fig5 a to 5 d show alternative embodiments of the closing elements 41 42 43 represented by 4 for optimizing the course of the cross sectional change during the adjustment of the closing elements the closing device valve body can have a curved shape below the valve seat 4 in order to achieve a progressive control action depending on the desired control action the curvature can be concave fig5 b or convex fig5 a 5 c or can have a stepped shape in order to improve the sealing action of the closing elements 41 42 43 relative to the valve seat 5 at the housing a seal 15 can be provided on the closing element 41.