I have seen those clips before on You Tube and have them saved as favourites so have seen them a few times, you just get the odd glimpse of the locking mechanism so we can probabley draw up something similar.

Have you seen this clip sadly too short..

http://www.youtube.com/watch?v=nG4gsljBHro

or this one which is brilliant

http://www.youtube.com/watch?v=X7xm7jTyZ-w

Ken