It is a combination of two wedge mechanisms.
Yellow button and blue pin move in opposite directions.
Pink wedge consists of two portions fixed together by a sunk screw. Cross holes on grey base, yellow button and blue pin are for assembling purpose.

STEP files of this video:
http://www.mediafire.com/file/8ea4x0q...
Inventor files of this video:
https://www.mediafire.com/file/hi9y7z...