Blue crank, green conrod (door panel) and orange roller create crank slider mechanism (to some extent, because the roller can be replaced with a slider).
Lower fixed end of red spring is set at position so as to keep the green door panel firmly at its closed or open positions (to create anticlockwise moment on the blue crank at closed position and vice versa).
Inventor files of this video:
http://www.mediafire.com/file/n26ah7n...
STEP files:
http://www.mediafire.com/file/rwa9c5c...