Double spherical socket

It is used mostly on surveying instruments.
The orange socket is clamped by drawing the plates together with thumbscrews.
Advantages over single spherical socket: compact and large movement.
This mechanism is numbered 1548 in the book “1800 Mechanical Movements, Devices and Appliances”, Gardner D. Hiscox, 1921.

Inventor files of this video:
https://www.mediafire.com/file/3khhfz0aib0ofgl/DoubleSphericalSocketInv.zip/file

Видео Double spherical socket канала thang010146