Sheaffer snorkel

The most intricate and interesting filler there is. Twist the end to extend a tube. Only that tube needs to be in the ink. This is the cleanest filler around. never need to wipe anything off after filling. Then draw back the knob and press in. This step is just like the Sheaffer Touchdown filler. After filling, screwing the end knob back on will retract the snorkel.

The patents are understandably complicated, so little reason to post the picture. Here are two patents that seem to apply.