Portable lift table 3

[slickstyles5]

Hi,
I'm a junior engineer and have purchased the lift WXP36-15 from Prest-lift.

http://www.prestolifts.com/page159.html

I would like to know what the force at the handle would have to be to tip the whole thing over. How would I calculate that?

Thanks.

Gabriel

 

[TheTick]

It's on wheels. It will just roll.

 

[DesignerGuy16]

Have you tried asking the company? They may have that info on file.

What are you doing with it that you're worried about tipping it from the end? I'd think if you stayed within the vendor specs for capacity you'll be fine, unless you're lifting something very large and awkward.

James Spisich
Design Engineer, CSWP

 

[MiketheEngineer]

Simply sum moments about a set of wheels and you can find the load.

I guess you are speaking of vertical loads only - horizontal loads will just let the cart roll - as previously suggested.

 

[KENAT]

Hmm, you wouldn't be trying to turn one of these into a weapon loader would you? I seem to remember spending time on that particular project.

Anyway, the above have given you the basis.

You need to decide if the wheels are locked or free - if free then as above have mentioned horizontal forces in direction of wheel travel will make it roll not tip.

This is really just a high school level vector problem unless I'm missing something take a look at my diagram. If moment M is positive in the direction shown then you have a tipping concern.

As Jspisich says asking the vendor may be a good idea.

KENAT, probably the least qualified checker you'll ever meet...

 

[slickstyles5]

Hi Guys,

Thanks for the advice. I just determined the moment (assuming the wheels were locked) to flip the whole thing over. We are using this to support a test cell exhaust system. (A little awkward)

Thanks so much for the advice!!

Gabriel

 

[slickstyles5]

KENAT - Pretty cool drawing!!

 

[evelrod]

Pretty little illustrations. From what I see, it looks like the grip of the handle is directly over the centerline of the wheels in which case a vertical load would just bend the handle or break the wheels.
Sorry, but why would you load something like this so as to create a 'tipping hazard' ?

Rod

 

[CorBlimeyLimey]

If fully loaded, the (downward and backward) force at the handle (to lift the front wheels) would be far more than the handle could bear. Even unloaded it looks like the handle would bend first.

 

[slickstyles5]

Well we were studying the case where we were on a slopped surface to see if it would tip sideways. The other case was when a force (horizontal) was applied on our structure. It passed in all cases. A force of 165 lbs is required at the tip of our structure to make it tip. This is unlikely because someone would have to be in a ladder to apply this force. Anyways, this probably won't happen.

Thanks again guys!

 

[dvd]

Seems like a good example of the evils of FMEA-type exercises. Creator of tool has to report on possible problems and consequences of those problems. If the real problems are overlooked it doesn't matter just as long as all of the blanks get filled in.

I would be more concerned about the test cell causing tipping than the handle. If the unit tips due to handle applied forces a good weasly lawyer will be able to get out of that; if the unit tips due to problems caused by the test cell then you're on your own.

Some questions:

1.) Is the test cell being shuttled on or off of the lift?
2.) What forces are applied (and where) by the test cell?
3.) Will these forces cause overturning?
4.) Are there ways to stabilize the lift?
5.) What are the harmonic frequencies of the lift?
6.) What frequencies may be generated by the test cell?
7.) ... ad nauseum...?