The people answering apparently don't know that you can use counter-weights, cables and pulleys instead of a torsion spring. It takes more space, but it rock solid and safer to fix.
It is very common in some other countries.
It is very common in some other countries.
They seem far safer, longer lasting, and cheaper and easier to repair than springs, but are more expensive to install, take up more space, and probably cost more all in all compared to springs.
I found this that also goes into it:
https://engineering.stackexchange.com/questions/8692/why-are...
I bet those tubes go below the foundation though and god help you if the cable breaks and you have to fish those weights out to reattach it.
Maybe there is some easily reachable latch point on top or some sort of fluid pump port that will make it easier on you?