How to safely contain a fall of heavy equipment?

[Superslinky]

Hi all, I have a hoist that will be lifting roughly 5000lbs. My "weight" is in a skeleton frame (approx. 4' x 4' x 4')and will be lifted by cables. I need to implement something under it in case of a failure to catch it. I'm not sure what terminology to search for. I'm thinking air bags or some type of shock absorber. Any ideas to get me in the right direction?

Thanks

 

[chicopee]

If you decide to work under the load,you should crib it.

 

[SnTMan]

If I thought it was going fall I wouldn't lift it. If I did lift it, I'd follow chicopee's advice.

Regards,

Mike

 

[Superslinky]

No, nobody will be under it. But I plan to lift it with a cable. Everything I'm using has more than enough load ratings but I want a safety factor built in just in case. I also plan to cage the area so nobody can get close but I also don't want to crack the floor in the event of failure.

 

[IRstuff]

How far does it need to be lifted? One could imagine using hydraulic jacks to hoist stuff. How damageable is it?

I think that making sure you have sufficient margin (stronger) and redundancy (more) is a better way to go. Even a 2-ft drop would expend 13 kJ.

TTFN
faq731-376

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[MintJulep]

You're worried that it might fall.

So you want to place something underneath it "just in case".

But it's starting on the floor, right?

So how do you put something underneath without lifting first?

You are concerned with failure and safety, but now you need someone to work near or under your hazard to place your safety measure.

Just use redundant lifting cables of suitable capacity.

Or better yet, hire a competent rigging firm.

 

[Superslinky]

Ok, so obviously more detail is needed for MintJulep. It won't be on the floor. It'll be on a rack. I'm testing the load rating on an actuator. It's a rotary actuator. It needs to have a total capacity of over 5000 lbs in lift. So this is a test fixture testing the lift. No garuantees it will be built to spec regardless of how much engineering is put into it. Everything is built off premisise. It will also be tested to failure (the actuator that is) or nearly to failure and will be measured, inspected, and otherwise to verify capacity and accuracy of the design. I was looking for suggestions for safety in case of failure not for rigging firm recommendations or other banter. I'm confident nothing will break on my fixture (built in-house), but if the actuator fails the test weights will come down. Nobody will be under it or near the lifting portion of the test and it will be caged. It is also designed to 'contain' the weight as to not be able to leave the lift zone in the event of failure. I really just need a cushion.

I'm going to use industrial shock absorbers designed for this purpose so in the end I found what I needed. Thanks to everyone for your input.

 

[1gibson]

Obviously more detail is needed for everbody; why on earth would anyone assume you are building and testing a lifting device.

It is also difficult to not mention your poor terminology "in case of failure" when you know that it will definitely be tested to failure.

Take a step back and read your original post, with no other context, what advice would you offer?

Try this on: "I'm going to lift something to test a lifting device to failure, and I want to do it as safely as possible."

 

[Superslinky]

Its clear everyone needed more info. Nobody had to add the sarcasm though. I asked about ideas for air bags and or shock absorbers or something of the nature, not to make assumption of why and or how and without the crap. If you had nothing constructive to add then you could have just passed up the post.

 

[MintJulep]

If you want to know the best way to peel an orange you shouldn't start with "I've got this apple".

 

[Metalguy]

Cardboard honeycomb.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[GregLocock]

Just so next time somebody asks this -

-how far can the test mass fall if/when something breaks?
-what acceleration on impact can it withstand?
-what maximum impact force do you want the floor to see?
-what is the static load rating of the floor?
-how much vertical space is available between the target surface and the floor?
(-which planet are you on?)

Nothing wrong with shock absorbers if there is room, but cardboard boxes or airbags or even a water tank might be cheaper or more robust, depending on the exact scenario.

Cheers

Greg Locock


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[MiketheEngineer]

Good luck. Maybe a lots of steel and concrete might stop it - depending on the fall height....

 

[1gibson]

Closed cell foam, ask your shipping dept.

 

[dvd]

piled dirt or gravel.

 

[JohnRBaker]

And people always asked why we had wooden floors in the machine shop... and these were not your normal wooden floors made with planking, but rather square blocks set on end so that if someone did happen to drop something 'heavy', that it was easy to repair the floor.

And in a machine shop where we had not one but TWO 36-FOOT lathes, gear-hobbers which could machine a 12-FOOT diameter by 4-FOOT wide gear and where with one of our horizontal milling machines the operator's station was on the headstock and he moved with the machine, we could really mess-up a floor with the sorts of things we moved around the shop with from the overhead crane ;-)

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[KENAT]

dvd - or you could leave the ballast in the bag.

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[dvd]

KENAT - it's more fun to make a mess.

 

[KENAT]

Well, if it does drop, there may still be a mess.

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[zeusfaber]

Is there any scope to soften the load instead of softening the floor?

Waterbags have all sorts of advantages in terms of being able to add load gradually from a safe distance.

A.