The flap door has an opening angle of 110° and is supported on both sides by tension springs. The aim is to create a suitable manual force curve for different door panel weights (here: 2 to 8 kg) with the help of the adjustably mounted springs. A suitable manual force curve is positive at the beginning (when closed), i.e. force must be applied to open the door at first, and becomes negative at about 15-20° opening angle and then remains negative, i.e. the door opens by itself all the way to the end.
The shapes were imported as several DXF drawings and some of them were attached to the kinematics. In order for the energy storage to represent two tension springs, its force was doubled. The actually used range of the stroke is always marked in green. The drive rotates with 1°/s, so that the diagrams can also be read to be over the door opening angle.