Spring and threaded links

I was at the local hardware store looking for some spring or threaded links for putting up a hammock. Spring would be more convenient, but not
as strong.
They have 3/8 inch threaded links, rated at 2200 lbs like this:
http://www.google.com/products/catalog?q=%2Bthreaded+%2Blink&hl=en&um=1&ie=UTF-8&cid 813161763124965053
But everything has a warning sticker that reads:
"Do not use for overhead lifting of a load, support of human weight, athletic or playground equipment".
So, what do people use for hanging up a swing o hammock? Sure, this is all legalese to keep the mfg from getting sued and the 2200# stuff will probably hold me just fine. But what do professionals use who might be specing playground equipment? I don't see them ignoring such a warning. So what do they use and end up paying for stuff like this?
--
Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com
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I'm not a pro, but that technical climbing gear is definitely made, tested and rated to support people. I use aluminum locking carabiners to support me, practice prussik and abseil techniques, guy the ladder etc, and steel links and shackles for other lifting and hauling, to easily keep them separate.
Climbing and Rescue equipment isn't as rugged and idiot-resistant as industrial safety gear and users should get instruction.
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Paul Hovnanian P.E. wrote:
(...)

It wouldn't hold me at all.
I like my hammocks as horizontal as possible.
http://www.whiteblaze.net/forum/showpost.php?pp1405&postcount 
--Winston
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I dont know about the links but be real careful:
http://au.news.yahoo.com/thewest/a/-/mp/6396323/three-year-old-crushed-to-death-in-rotto-tragedy /
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wrote:

Chain/rope wrapped around when possible. 1/2" eyelet with the longest lag you can find if not.
I used a pair of 3/8" eyelets inside for a hammock chair (30" separation) and they have some spring to them. I weigh 215, so the 2200# seems a bit optimistic. Maybe that's the shear figure, not the uncurl figure.
If you go with 3/8", double them up for safety, in case a herd of kids decides to pay you a visit.
And run a 4x4 between the two uprights. Most porch uprights I've seen aren't anchored very securely. The last one I replaced had just four 8p nails holding it on top. A petite woman in a hammock would have pulled it right down.

Love it, Paul.

FOUR kids (probably at least one jumping) in the hammock when it collapsed? Yeah, what did they expect?
-- Make the best use of what is in your power, and take the rest as it happens. -- Epictetus
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Advert posted without.
LLoyd
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This will be the force to pull it apart in a straight pull. A taut hammock with a 215# person in the center could easily achieve this, due to the mechanical advantage.
If you need real strength, using hardware where the stated safe loads mean something, use only industrial or marine hardware, none of which is available at a hardware store near you, or cheap.

Make sure the loop is forged or welded shut.

And don't pull the hammock too tight. The mechanical advantage of pulling sideways on a taut rope is immense. People pull eye bolts out all the time.

<http://au.news.yahoo.com/thewest/a/-/mp/6396323/three-year-old-crushed-to-death-in-rotto-tragedy/
I bet that the hammock had been pulled straight before anybody got in, too. It would be easy to pull the pillars down unless they were designed and built for such loads. The Rottnest Island Authority probably now wishes that they had forbidden attachment of hammocks to the pillars.
There may also have been a construction blunder when the facility was redone.
Joe Gwinn
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On Thu, 30 Dec 2010 11:55:27 -0500, Joseph Gwinn

Anyone putting up a taut hammock doesn't know what they're doing. It will strain the crap out of any physical holder and tip so easily they'll never be able to stay -in- the thing.

I'd certainly agree with that.

Excellent idea.

I hadn't realized just how much force was applied until we had that discussion on tow trucks and winching here in the last year or two.

No kidding.

I wonder if it's cheaper to get an architect to spec things over there than a structural engineer.
-- Most people assume the fights are going to be the right versus the left, but it always is the reasonable versus the jerks. -- Jimmy Wales
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Larry Jaques wrote:
[snip]

Right. The hammock itself can snap.
What sort of certified, industrial grade material is the hammock made out of? Probably nothing as good as a 2200# rated link.
I can figure the loads given a certain weight and slack. So I can pick something off the shelf that will be at least as safe as the rope. The worst case will be my falling on my ass a few feet (not like that kid in WA that pulled a column down on himself).
--
Paul Hovnanian snipped-for-privacy@hovnanian.com
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wrote:

Indeed, on a tight rope, ANY transverse load produces an INFINITE stress initially. Not until there is some deflection in the rope does the stress become determinable. That "infinite" stress also applies to the end connections.
The hammock should have as much slack as possible; If you like it tight better have someone knowledgeable calculate the loads and stresses.
Wolfgang
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