I'm trying to find the original very informative video from a decade or so ago, but I've found this pdf[1], which mentions the heart of the mechanism as a disk/spring on page 19. Some product training in this pdf[2] touches on the mechanism as well, as does page 39 and 156 of this pdf[3]

Here's a PDF from Wyler's own site[4] about the Zerotronic, with the mention of the "pendulum" on page 7.

[1] https://ftp.wylerag.com/Downloads1/WYL_e_wyler.pdf

[2] https://www.someco.fr/wp-content/uploads/2021/08/zerotronic_...

[3] https://symetrie.fr/wp-content/uploads/2023/09/WYLER_Catalog...

[4] https://www.wylerag.com/fileadmin/pdf/manuel/zero_e.pdf