pulley system for telescoping crane

[anchange]

Hey guys,

I'm trying to figure out how the pulley system / gearing works on something like this -

http://www.chapman-leonard.com/products/telescoping%20crane%20arms/15'%20Telescoping%20Hydrascope.htm

 

Basically some kind of pulley system make the front 2 telescoping sleeve move in and out in unison as well as making the back counter weight slide to compensate for added or subtracted force on the front end.

 

In addition the places that the camera is mounted stays level to the base as the crane is arced up or down.

 

Any ideas?

 

another picture -

http://www.panavision.com/product_detail.php?imgid=158&id=110&cat=103&PHPSESSID=6kn8scjcplmgfn5i5nlnop1il6