how dose a quck release bucket work?

[cosworth34677]

i want to make a quck release buck for the excavator. i've seem them where there is no hydraulic or any kind of mechanical way of locking they just hook and go. how dose that work? can someone please explain that? kind of stumped. and if you can find some pick of that setup please post thanks

[Lil Giants]

Here's pics of the Vario quick attach. 4 side plates, 1 cross plate & brace, brass cyl with a spring in between two pins. Front hooks into a welded in shaft at the front of bucket, back of bucket just has holes.