DE 77f

From the Swedish patent's office's "Introduction to the German Patent Classification (DPK)" online:

The German Patent Office started developing a classification system for its patent documents in 1877. It was published in seven editions between 1906 and 1958, first as "Verzeichnis der deutschen Patentklassen" and later as "Gruppeneinteilung der Patentklassen". Between the editions, modifications were published in the form of "Änderungen" and "Ergänzungslieferungen".

The subsets of the German classes are listed in English on the Swedish site here, and in particular class 77's subsets, linked from that page, are listed here. In that context, DE 77f covers the category of "Toys." We don't know for certain that the meaning of DE 77f was the same at the time early aero.

References

This wiki has 2 patents in category "DE 77f".

Patents in category DE 77f

• Patent DE-1896-95914 (English title: Airship with concave, curved, sharp edge forming its bottom surface, Inventors: Carl Götzke • Karl Götzke, Filing date: 1896-09-25)
• Patent DE-1905-166740 (English title: Roof construction for toy buildings, Inventors: Friedrich Adolf Richter, Filing date: 1905-03-07, Applicant firm: F. Ad. Richter et Cie)

Enclosing categories	DE 77
Subcategories	DE 77f.23, DE 77f Gruppe 23
Keywords	toys
Start year
End year