Looking for 500 lb chain fall found article!!!!

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bvd1940

bvd1940

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Have been trying to find a 500 lb chain fall (chain block/hoist) and have had no luck. ???
In my younger days it was hard to find higher tonnage hoist and the small light weight hoist was real common.

I need it for loading my mill and lathe and need the short height & fast chain action as overhead is limited.

I also had found a shop built chain fall on the internet but can not seem to find now and it was perfect for my application. ???

Any leads would be greatly appreciated. :bow:
Thanks to all of the feed back & the link :bow: ;D
http://www.frets.com/HomeShopTech/Projects/MiniHoist/minihoist.html
 
Have you tried looking at Northern Tool, Harbor Freight, Tractor Supply. Not sure if any of these supply companys are near you. Try E-bay, might find one from the good ol days.

Craig
 
Bill, if your overhead is limited, have you considered an engine hoist (cherry picker)? If it's a one-time need, a rental center should have one.

Rudy
 
Look for a comalong. You want the chain type, not the cable type. It will take up less headroom than a chain fall just slower acting.
 
CMS said:
Have you tried looking at Northern Tool, Harbor Freight, Tractor Supply. Not sure if any of these supply companys are near you. Try E-bay, might find one from the good ol days.

Craig
Click to expand...
Been there done that ;)Thanks.
 
rudydubya said:
Bill, if your overhead is limited, have you considered an engine hoist (cherry picker)? If it's a one-time need, a rental center should have one.

Rudy
Click to expand...
Have a cherry picker, I need sumptin to fit on my jib boom that is not to tall from hook to hook. ;)
I need a light on as its for mill vice/lathe chucks etc. on jib boom.
 
OK, a really dumb question... I looked over the linked mini-hoist project page, and I am baffled. Where is the mechanical advantage? It looks like he made a 10/11 pulley from one piece of solid brass. I can't see any advantage of his mechanism over a simple pulley.

On my commercial shop hoist, there is a gearing inside which requires maybe a foot or two of travel of the lift chain to raise the load an inch; I'm guessing a 15 or 25 to 1 compounding.

Am I missing something?

http://www.frets.com/HomeShopTech/Projects/MiniHoist/minihoist.html
 
How about a small block and tackle, like hunters use to hang up a deer to skin it?
 
Ok, Some here will already know this and don't need any preaching. And I'm a long ways from any defination of a safety natzi. I've been doing well above what would be considered as a heavy lifts in HSM terms for well over 30 years. Many, many multiple tons above that. I've also seen brand new industrial rated equipment fail for no aparent reason at under it's rated capacity. If your thinking of building something like this? I'd not use brass for anything but the bushings. I wouldn't even use scrap steel material for any of the parts unless it was built with a safety factor of at least 10 to 1. Anything your likely to lift with this would be consider as a high value lift. Shop equipment of this type also has a very bad habit of being used beyond its capabilitys because it's handy.

It's bad enough to damage something you've pinched pennies and saved for. Any parts of a human body under a failed lift.................? I own a 2 ton Chinese built engine hoist. I automaticly down grade that to less than 1,000 pounds. In industry I'm required to inspect all lifting rigging before using it. In 30 years, I've yet to see any that was manufactured in China. If the object your lifting weighs more than you do? That's not the place to cut corners becauses of a few bucks.

I'd hope anyone reading this will take it for how it's meant.

Pete
 
Mainer said:
@Swede:
I've not seen the article and the link you provided isn't working for me right now, but I think you may be talking about a differential windlass, sometimes called a Chinese windlass. It's quite an ingenious low-tech solution. Does this look right? http://en.wikipedia.org/wiki/Chinese_windlass#Differential_windlass
Click to expand...

Thats it exactly... The author, who does really nice work, BTW, created a solid brass sheave with two sections like the Wiki article, one with 11 teeth, the other with 10. This creates a little bit of advantage, but not much, only ten percent or so. If one had say five teeth, and the other had 25, it would certainly do the job.

There was also no brake or other mechanism to hold the load once raised.

I dont mean to beat up on him... The machining is top notch. I just thought I was missing something in his design. You may as well throw a dacron rope over a pulley, as afr as I can see.
 
Swede, I think you are looking at this system backwards. The closer the two joined pulleys are to the same size, the greater the mechanical advantage. You have to move a lot of chain to change the elevation of the load a small amount but the effort required to raise the load will be a lot less. If the pulleys are much different in size the load will move faster but the effort required will be much greater. By having the pulleys close to the same size the system is always close to equilibrium and a brake is not needed.

See Wikipedia http://en.wikipedia.org/wiki/Differential_pulley
 
Not to start a debate or anything - I understand how a differential pulley works, and the illustration in the Wiki link you posted is a good example. Note the Wiki device has two connected sheaves, one twice the diameter of the other. Pulling on the rope of the larger diameter sheave will give a large mechanical advantage, allowing one to raise a load which goes over the smaller. Without doing the math, pulling the large sheave rope a foot would raise the load say 4 inches.

In the device in question, the maker made a pair of sheaves that was a 10/11 ratio - essentially the same size. For the sake of argument, we can call them the same, in that a foot pull of the large sheave chain would move the small chain say 9 or 10 inches... there's an advantage, but not a big one, and releasing the chain would allow the load to free fall. I think a better device would have a greater ratio.

Oh well, it's not that important. I thought I was missing something in the design. Thanks!
 
The principal of the mechanism isn't obvious at first glance. I've used them, the commercial ones have cast gears that grip hoisting chain. The mechanical advantage is so great that they don't need a locking mechanism to hold the load.
By the formula in the link, the 11 and 10 tooth sprockets would give 220:1 ratio.
Greg
 
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