I Thought This Was Obvious!

Sorry for the naysayers about those of us who see the need to give answers based upon the numbers that come from real-world testing and experiments that tell us, pracitcally, what to expect in the real world scenarios.

The OP had a real world scenario, and it is surprising to those of us without the experience to know, what to expect in real world applications. Yours' and some of the others' analysis, for those who know how to study the data and graphs, give some valuable information that will be helpful for anyone in the future who has this kind of thing to do.

Thank you!

I like to shoot from the hip with answers, but only in areas that I have sufficient experience to have conficence that I won't make a fool of myself or others. I think that there is a reason some things are well advised to be left to the experts... and few of us should consider ourselves experts in many areas. The rest of the time we should have access to expert consultation, in forums like this.

I just wish it were easier to keep the riff-raff off the topic... It makes it difficult for someone looking for valuable, real world, practical consultation to sort the good answers from the _)($#$%^&*

Thank you for the kind appreciation, it is always a pleasure if a work can be of help.

May I mention an interesting aspect in loads handling. If you have a structure on which you bring a load till it is in touch and then let it free an over load will occur and this on is not small as following computation shows.

All structures are deformable more or less since infinite stiffness does not exist in the real world.

When you let the load free it is at rest but under the gravity action so that a G force will act upon the structure (let is have the stiffness "C") which is not yet under load. Under this force the structure deforms and the mass moves till a balance occurs. This is the case when the energy of the mass is equal to the one of the structure deformation. Let this stroke be "h" so that you have : G*h = C*h^2/2 thus h= 2*G/C ! This means that in this situation the maximal load on the structure is 2*G. Very few think about this dynamic effect and if structure do not collapse this is because the tress design level is very low with respect to the elastic limit of materials or the ultimate portance of the structure.

As it was said above safety is in the range of 4.

Once more a short computation gives a lot of information in order to avoid failures.

But the question was not to design a dolly it was limited only to the load distribution when the container is already on it.

and back to the real world....and hats off to anybody who designed their first caster frame and then replace all the wheels a month or so later - you know who you are!

I found a 20k# caster at castercitydotcom (really such name).

The great thing is the note at the end

You should never select on the basis of load capacity alone. Capacity ratings do not take into account the effort required to manually move a load. Capacity ratings are based on manual operation under ideal conditions. If these casters are going to be moved by mechanically powered equipment, consult us for a reduced capacity rating based on your application. If a human being has to move the weight, select the largest practical wheel diameter.

If a caster failure occurs it is almost always because of misuse or abuse. It has been very rare that a product failed because of faulty material or poor workmanship. The following are examples of things that we do NOT want you to do:

Ok back to my 5 sec vote: 15k# per wheel target *1.5 and we get 22k#, I would pass on the the 20k# units unless I could not find a 25K# job although I would be even more happy with a 30K# unit. And then if I had time I would call and say, "what happens at 5mph!"

Don't forget this was supposed to be a 5 sec decision.