Okay for some reason my dad’s supervisor at work asked him this problem about pulleys moving massive amounts of weight. Now, the question should be “why is this white collar supervisor type guy asking the blue collar sheet metal worker this, when the supervisor has most likely been to college” but that is neither here nor there.
Anyway, I tried to look up some stuff about pulleys online but I was a bit baffled because I don’t know Newtons from pounds and pretty much I am not willing to put a whole lot of effort into this problem. I know you Dopers are near genius level, so perhaps someone can help me out.
What is the best pulley system for moving 128,000 lbs. 10 feet laterally (that is not up, but across a floor).
I know we have to account for friction, but let’s assume this thing is on wheels (well actually, it IS). Also let’s assume the floor is flat with no inclines.
Is this something that you can even do with a pulley system? I have never really considered pulling something sideways with a pulley but i guess it would work.
A pulley system like the one you’re thinking of is basically a way to trade pulling force for pulling distance. You get the same results for pulling twice as far with half the force, or 4 times as far with one-quarter the force, and so forth.
If the weight is on wheels, and the cable you’re using can take the full weight without breaking, it’s just a matter of adding enough pulleys and loops until you get the force down to a low enough level for you to pull.
This diagram should help. See if you can get your hands on an Intro to Statics text.
Now that I reread, I see you’re moving the load laterally. Er, extend that 8F line in the link down around a pulley at floor level (or rather, the level of the c.g. of the weight you’re moving) and out to the weight.
How are the wheels? Do they have ball bearings in them or are we talking about one step above Erector set? You need a cable and system strong enough to withstand the inertia (a slower pull would help this) and the friction in the wheels; it doesn’t necessarily have to support 128 kps tension.
Nah, I’ve had plenty of managers who didn’t know shit about engineering. They either didn’t take the relevant classes or have long since forgotten anything they learned in them. Anyways, even among people with some mechanical knowledge, the gear heads are generally going to be more effective at implementing this sort of thing than the cone heads are.
While many good intentioned SDers are willing to do your homework you didn’t provide enough information. What is available to attach the stationary pulley to? How much room do you have? What is the motive force available to pull the rope? A bunch of guys, your dad or a winch?
Which is just two rods with several pullies on them. Each rod is put into a rectangular frame for additional strength. A block and tackle allows you to loop the rope between the rods lotsa times and multiply your force applied (at the expense of distance) a lot.
No really, this is not for school. If i had a physics book i could figure it out. My dad’s boss did actually ask him and the info i gave you is actually all i do know about it.
