|D28 / 9||-> 10||-> 14||-> 20||-> 4|
uspto searchesPatent Apps in D28/20
Granted Patents in D28/20
Advanced search in patft or appft for the hierarchy would be:
(ccl/D28/20 or ccl/D28/4)
Press the Search button below to send the query to the USPTO site. (Granted patents search)
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.