Hierarchy/Derived subclasses
| 213 / 220 | -> 221 | -> 222 |
| -> 223 |
uspto searches
Patent Apps in 213/220Granted Patents in 213/220
Use the links above or do an advanced search in ppubs for:
(213/220.ccls. or 213/221.ccls. or 213/222.ccls. or 213/223.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.