drmini in aust wrote:
smac wrote:
Hehe...I love this topic. Next thing to happen is someone (like me) asks how the force at a particular point in a closed system can double while the overall force somehow stays the same, and then people start arguing with bad science, and it's
great!

It's just snatch block mechanics technology. The top mount in a retractable system acts as a pulley. As old as the hills, older than me even.
Ask any woodcutter or serious offroad 4WD enthusiast.

Ya but that's where the bad science comes in
The reason a pulley can lift twice as much (for the same force) or in this case exert twice the force is only if
the distance is doubled. That's the important bit that gets missed from these (numerous!) threads. In this case the total distance the belt being pulled out does not change (in fact I think it halves due to the pulley, and that's how the force is the same).
I don't claim to know all the answers on this one yet, I'm still thinking (it takes a while!) but I DO know it's not as simple as it seems.
Don't get me wrong though - I completely agree using an "unre-enforced" (it's now a word) bin is a no go. The belt can't act as the re-enforcement as suggested above because it's the surrounding bin metal that's the problem. You'll either pop your mount clean through the bin metal, or as doc says pop the bin off the floor.