Stability of a high center of gravity Crane 1

[GTRVspec]

Hello

My question evolves the evaluation of the mobile gantry crane (on rollers) and making sure I have adequate base, thus preventing “tipping”. How can I determine a minimum length of the base members?

Thanks

 

[mloew]

Well, for minimum static stability, the CG's vertical projection must always be within the support boundary. But there are obviously dynamic conditions and factors of safety to consider. Are there any industrial specifications for this type of equipment?
Best regards,

Matthew Ian Loew

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[GTRVspec]

Mleow

Thanks for responding, I was starting to think it was a dumb question(we all know what our profs. said about that). this project is odd in it self as the gantry crane is being dessigned for a client who wishs to use it in his home garage to pull engins. It gets better with a 2000lbs lifting and a 12ft lift hight. Plus I'm not sure where to place it in the codes (industrial or home) so I selected a safety factor of 2. I've started with a assumed 5ft base of W150x22. In theory there is no horizontal forces acting the CG. So as you can see it is some what odd problem

Thanks again

 

[GregLocock]

If he can walk underneath the crane you'd better use a factor of 4, 2 is the test load. Cheers

Greg Locock

 

[dooron]

I very much suggest that you open a crane code design book to look at requirements for mobile cranes and at a design safety factor. Because its one of design I suggest that you consider (on ultimate load) of at least 8 to 10, not less. That is 5 to 7.5 on yield, and test it with a load 3 to 4. Photograph and record the test to keep a record that it has been tested.
The test should be at the worst expected position of work,including tipping. Then you can sleep a night when the guy lifts the engine out and at the same time lifts the whole car because something got snagged.

 

[HamishMcTavish]

You could try "Cranes: Design, Practice and Maintenance" by J Verschoof as a starter reference.

http://www.amazon.co.uk/exec/obidos...li_/026-0318636-7737232?coliid=I3E4EVEED3863X

No more things should be presumed to exist than are absolutely necessary - William of Occam