Hashem71, you have just uploaded 3 files showing cranes :
1_crane[1].DWG , -------50M[1].DWG and -------60M[1].DWG.
I'm interrested with cranes and i'd like to know more about yours.
What cranes are shown in your files : brand, model, capacity, etc... ?
Your files are declared in inches but they are drawn in millimeters and meters, please modify DDUNITS. 
You have drawn your objects in meshes, why not solids ?
Please add some dimensions.
I hope to read you soon...philippe JOSEPH2014-09-03 07:57:35