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How much force would it take to open a locked restraint?

cjbrandy

cjbrandy

Hyper Poster
So, restraints from lap bars to OTSRs have one purpose: to make sure when the ride/coaster comes to a stop, you're still in it! But have you ever wondered how much force it would take to open one mid ride? I'm sure they're designed so even if Dwayne the Rock Johnson pushed with all his might it wouldn't open (well I hope so anyway) but I certainly would be too scared to try it especially on coasters where there isn't a failsafe belt like Gersts and some B&M hypers like Shambhala to name a few.

Does anyone know roughly how much force it would take? And in Newtons?
 
Hmm... as far as I can remember, the locking mechanism for Intamin's seat belts (from Kanonen and SpeedMonster, at least) are rated for 12 kN, and the belt itself for 20. That means you can safely pull up a car with it.

As for metal locking pins for restraints, the required force would be significantly higher. Assuming a yield strength of 355 MPa (standard for structural steel) and a cross-section of 1 square centimeter, you need a force of 35.5 kN to pull the pin apart. And 1 cm2 is a very small cross section. If such a force was applied to a restraint, I think the bar itself (which is usually hollow) would buckle before the locking pin snapped.
 
I think Poke is pretty much right (as right as you could be without seeing the full design and test data). His numbers for the belt and buckles sound sensible and are in line with what you'd expect from devices of that nature. His quoted figures for the shearing forces are correct too, which you can clearly see gives a much higher force than the belt/buckle.

All in all, the answer is "a lot". More than I think you could ever exert as a human.
 
Happened to me on Revolution at Blackpool, going down the first drop the restraint started to open. I just grabbed it and pulled it back towards me as we headed up into the loop and luckily it locked again. Long long time ago though and restraints are different now
 
Pokemaniac said:
the belt itself for 20 kN.
Click to expand...
Some roller coasters could carry an even higher rating.

I have noticed belt material on some roller coasters that is similar in design to climbing harness belts rated for 5,000 pounds of force (2.5 tons or 25 kN). 20 kN is equivalent to 4,000 pounds - enough to hold two Smart Cars and then your own personal weight. What is fascinating about this belt material is it's ability to hold weight even when sliced - typically you need to get over half way through the belt for true integrity loss in weight rating. VERY strong!
 
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