Here's some information from Hahn:
Scantling Lamp Family
A domestic floor lamp made from timber. Without the need for any counterweight this light’s adaptability relies on a hidden mechanism that uses friction without the usual self-loosening.
To be used above dining tables this lamp uses the same mechanism as the floor lamp. Because the whole construction is suspended from a hook in the ceiling, the light is free swinging.
This allows the user to adjust the height of the lampshade by simply changing the angle of the wooden components. The position to the sides stays the same as the lamp is pivoting on the hook.