A stackable container having excellent resistance to impact breakage includes (1) a plastic tank for containing liquids having at least one opening in its upper end and upper and lower abutments extending around sidewalls, (2) a top member engaged to the upper end of the tank having a downwardly facing...http://www.google.es/patents/US5361906?utm_source=gb-gplus-sharePatente US5361906 - Fluid container with sump
