International Patent Classification (IPC)
The Strasbourg Agreement concerning the International Patent Classification, concluded in 1971, aimed to overcome the difficulties caused by using diverse national patent classification systems. The common classification system defined by the Agreement is applicable to patent and utility model documents.IPC is supervised periodically - every five years - in order to make the system perfect and to follow the technical progress. However, the Strasbourg Agreement was signed by less than thirty, the classification codes are indicated by more than fifty countries. Hungary is not a member of the Agreement but indicates the IPC codes in the official Gazette and in patent specifications.
The revision, continuous enlargement, refining of the IPC is supervised by the World Intellectual Property organization. A publication is valid for five years, at the present the sixth publication is in use.
Validity of different IPC publications:
1. September 1, 1968 - June 30, 1974
2. July 1, 1974 - December 31, 1979
3. January 1, 1980 - December 31, 1984
4. January 1, 1985 - December 31, 1989
5. January 1, 1990 - December 31, 1994
6. January 1, 1995 -
The organization of IPC:
The International Patent Classification is a hierarchical system and represents the whole body of knowledge which may be regarded as proper to field of patents for inventions, devided into eight sections:
| A | Human necessities |
| B | Performing operations; Transporting |
| C | Chemistry; metallurgy |
| D | Textiles; paper |
| E | Fixed construction |
| F | Mechanical engineering; Lighting; Heating; Weapons; Blasting |
| G | Physics |
| H | Electricity |
The structures of the sections:
- classes: A 61,
- subclasses: A 61 N,
- main group: A 61 N 1/00,
- subgroup: A 61 N 1/36.
- subclasses: A 61 N,
The hierarchy within a subgroup is only determined by the number of dots before the definition and not by the numbering of the subgroups.
Non-hierarchic elements: main headings in subclasses
Cross-references: initiated with "to be preferred", "transferred to", "includes".
Italics: new marks
Square brackets: change of generation, e.g. [3,4]; the mark is valid from the given generation: e.g. [6].
Indexes: They contain the entries in alphabetical order characteristic of different technical fields. It is advisable to commence the research here or to navigate in the hierarchy in the IPC volumes to get to the required codes.
Revision concordance tables:
They show to which new or already existing code were the "technical content" or part of it in the classification system transferred during different IPC versions.