strange ratchet mechanism

[Aerolight]

On my crane topic a large moc from Spain was given as a possible guide, the part that was odd was the mechanism for looking the telescopic sections together (when at max extension) then releasing them if the section was moved past its max (allowing it to be fully retracted). I built a copy of this to test and I just cant see how its meant to work (carbon copy except from elastic band placement  but it can only have one function at least I think) the original creator of the moc says it works but I cant find any pictures of the jib extended (pictures of it extended would also show how its meant to lock). Here's the link if you want to see a super impressive crane or decode the mechanism better than I have: https://itlug.org/forum/topic/7536-gru-telescopica/page/1/

IMG_0414 by michael waterfield, on Flickr

Any thoughts on a such a ratchet or the reasoning behind the strange build of this one?

[Kladovec]

If you translete his (Italian guy) article, you can find out, that he´s using in his largest boom (15 x 15) section some inner boom with 5 x 5 dimensions. In which is located some, for me didn´t understanded mechanism. This inner section is with some rope and ratchet. But how it works .... hmmm, who knows? Maybe something like this.

[Aerolight]

I did not expect someone to make a whole diagram for it props to you. I could under stand if it was the locking of the carrier that disengages the ratchet but the creator says that it is just the movement of the section 2 studs past its locking point that releases it , meaning it should work no mater what was inside of it. I just finished my version of the stage carrier and managed to get one to work (in the exact same way as the diagram) in a 5x3 but with a slightly modified 2x1 that is free to move on the drive from the inner motor (although the longest single axle I know of is from the old tow truck; which is the one I'm using, and the Italian moc would need one far longer so it might use a second cable to trigger the carrier lock). 

[steph77]

i used a similar system in this moc:

Spoiler

Mahybe it helps...

Steph