Der Winkel der Rippen soll als gedachte Linie der eingeleiteten Kraft an der Oberkante des Scheibensitzes auslaufen, jedoch mindestens 20° betragen.

I've read through this sentence quite a few times now and I have to admit I'm still not quite sure what is meant by an angle that "ausläuft". Could one translate it simply as "should be"? Or perhaps "should end up being"?

(If there are any masochists out there, translations of the whole sentence are also welcome, but I'm pretty sure I can manage it once I know what is meant by the Winkel, der auslaufen soll.)