Safety Factor

[Creech]

Can someone tell me the saftey factor for a lift truck. Like a special fork lift. no one will be under it. It has to lift 8000lb, flip it then bring back down.

 

[ietech]

There are several safety constraints in lifting a load with a lift truck. All forklifts in the U.S. must have the safe operating loads on a data plate that is easily accessible/visible on the lift unit. This data would include CG, max load at full extension, attachment or accessory restrictions etc. etc.

My recommendation for accurate info, if you are looking to buy or rent, is to contact a reputable vendor. It sounds like the lift you either have or require must have special characteristics to allow it to flip a load. I would definitely contact an EXPERT.

Good Luck,

ietech

 

[Creech]

I guess what I'm asking is how the load capacity is established for a fork lift and how it relates to the safety factor in the design.

ex. the fork stresses and strains analysed might yeild a safety factor of say "4" to lift say 1000lbs and I lable it "Max Capacity 1000lbs". Is that safe enough or is it insufficient. What is the standard and or does anyone know where I can find that for a fork lift or something similar.

 

[Cockroach]

Yeah,I'm with Creech except I would probably go with 3, same as that used in bolting and other fastener design. Depending on your economic situation, budgetary concerns and what have you, higher may be acceptable.

I've done gibbs and alternate cranes to 2 1/2, but had absolute certainty with MTRs and craftsmanship, merchantability issues.

Your call, but at least you have an ball park estimate.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[unclesyd]

If you are in the US get a copy of the OSHA and ANSI standards for fork lifts prior to starting your project. There are very strict regulations as to what can be altered, changed, or repaired on fork trucks. Any thing other than routine maintenance requires the OEM concurrence and approval.

The fork lift you are considering is a very specialized lift and you will be hard pressed to find a local representative well versed in fork lifts of this size and type. Moving a load of that magnitude after lifting as mentioned in previous post is all about the important CG as well as few other things that hold the load.

I've been involved in investigations of serious accidents with Fork Trucks that had serious injuries. Two accidents were prior to OSHA and the last one was with OSHA, they were not much fun to work with. They were right so there was no argument, the fork truck had an unauthorized modification.

I would at the fork lifts used in the metals industry.

 

[Barry1961]

The common safety factor for lift trucks and overhead cranes is 10. This can be found in most chain catalogs that have leaf chain or hoist chain. This of course is for working over people.

Of course the chain pull should be calculated under a jam/stall condition and "E-Stop" and not by weight of load under normal conditions.

How much safety factor you need is mostly determined by how much damage/liabilty might be incurred if there is a failure.

Barry1961