Hierarchy/Derived subclasses
252 / 500 | -> 518.1 | -> 520.2 | -> 520.21 |
-> 520.22 |
uspto searches
Patent Apps in 252/520.2Granted Patents in 252/520.2
Use the links above or do an advanced search in ppubs for:
(252/520.2.ccls. or 252/520.21.ccls. or 252/520.22.ccls.)
This will show what classes derive from the input. Ex: entering 43/42.24 shows the derived classes and the search that can be used to find patents or patent applications in those subclasses.