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Ludmila Lisovskaya

Patent Specialist / Chemical Specialist

13 January 2020

What types of a patent classification are there and what are they for?

A patent classification is primarily a tool for patent offices and other consumers carrying out various searches for patent documents. The consumers include the patent attorneys, the patent examiners, the employees of research institutes, the employees of enterprises, in particular of patent departments or design offices, the individuals or the representatives of legal entities that plan to defend their technical solution with the help of a patent or to check whether they violate somebody's exclusive rights, etc.

Currently, the search for the patent documentation is usually carried out using the International Patent Classification (hereinafter referred to as the IPC), as it is used by almost all countries in all modern automated search systems and databases as a search attribute.

The IPC is a hierarchical system of the patent classification, which is uniform internationally and it is a means for the classification of the patent documents, namely the patents and the copyright certificates for inventions, utility models, including for the published applications. The IPC was established in accordance with the Strasbourg Agreement in 1971 and it is updated on a regular basis by the Committee of Experts consisting of the representatives of the signatory states (the countries of the Agreement) and the observers from other organizations, such as the European Patent Organization, while the administrative functions of the Agreement are performed by the World Intellectual Property Organization (WIPO).

Each patent document of all countries of the Agreement, as well as of the majority of others, has at least one classification index of the IPC indicating the field of technology to which the invention refers. The multiple indexes can also be determined to ensure more detailed information on the content of the document.

The IPC appeared on the basis of the International (European) Patent Classification, which was established in accordance with the provisions of the European Convention on the International Classification of Patents for Invention in 1954 and it was published on September 1, 1968. In 1967, the United International Bureaux for the Protection of Intellectual Property (BIRPI), the predecessor of the WIPO, and the Council of Europe began the negotiations aimed at granting the status of a truly “international” one to this classification. Thus, after the signing the Strasbourg Agreement on March 24, 1971, this classification was considered to be the first edition of the IPC. The predecessor of the current IPC consisted of eight sections, 103 classes and 594 subclasses. Subsequently, the eighth edition of the IPC consisted of eight sections, 129 classes, 639 subclasses, 7,314 basic groups and 61,397 subgroups.

The IPC is reviewed periodically with the aim of improving the system taking into account the technological developments. Seven editions of the classifier were issued before December 31, 2005. This happened practically every five years. However, it was a paper based information tool. For the effective application of the IPC in an electronic environment, a reform was carried out from 1999 to 2005, which resulted in that the eighth edition of the IPC came into force on January 1, 2006.

As a result of the reform, the IPC was divided into a basic level (with a three-year revision cycle) and an extended level (with a continuous revision). This made it possible to meet the needs of the different categories of users. The changes related to the reclassification of the patent documents under the changes of the IPC and the use of the advantages of an electronic layer were made.

The IPC has been revised annually since 2010 and the new edition comes into force each year on January 1.

The edition of the International Patent Classification of 2015 – the IPC-2015.01 – comes into force on January 1, 2015 and it contained 71,738 headings.

The IPC covers all fields of the knowledge, which subject matters may be subject to the defense by the protection documents. There are five basic levels of hierarchy to specify the field of technology[: 1 – Section; 2 – Class; 3 – Subclass; 4 – Group; 5 – Subgroup.

The further clarification occurs through the subordination of some subgroups to the others.

Each subject matter of the classification consists of an index and a descriptive part. The index of the subject matter, in addition to the sections, consists of the corresponding index of the previous level and a letter or a number added to it. The descriptive part, as a rule, consists of a title of the subject matter and a short list of the topics relating to it or the headings. Thus, the classification index is formed, under which the specific technical solution is “hidden.”

The IPC is divided into eight sections. The sections represent the highest level of the IPC hierarchy. Each section is indicated by a capital letter of the Latin alphabet from A to H. The sections have the following names: А: The satisfaction of the survival needsof a person; В: Various technological processes; transportation; С: Chemistry; metallurgy; D: Textiles; paper; E: Construction and mining; F: Mechanical engineering; lighting; heating; engines and pumps; weapon and ammunition; blasting workings; G: Physics; H: Electricity.

Each section is divided into classes. The classes are the second level of the IPC hierarchy. The class index consists of the section index and the two-digit number. The class title reflects the content of the class. For example, A01 – Agriculture; forestry; animal husbandry; hunting; trapping; fishing and fish farming.

Each class contains one or more subclasses. The subclasses represent the third level of the IPC hierarchy. The subclass index consists of the class index and the capital letter of the Latin alphabet. The subclass title determines the content of the subclass as accurately as possible. For example, A01B – Tilling in agriculture and forestry; units, parts and accessories of agricultural machinery and implements in general.

Each subclass is divided into groups. In turn, the groups are divided into basic groups (i.e., the fourth level of the IPC hierarchy) and subgroups (a lower level of the hierarchy compared to the basic groups). The IPC group index consists of the subclass index followed by two numbers separated by a slash.

The basic group index consists of the subclass index followed by the one-, two- or three-digit number, the slash and two zeros. The text of the basic group determines precisely the field of technology that is considered appropriate for carrying out the search. For example, A01B 1/00 – Manual implements.

The subgroups form the headings subordinated to the basic group. The subgroup index consists of the subclass index followed by the number of the basic group, which this subgroup is subordinated to, the slash and at least two digits other than 00. The subgroup text is always understood within the limits of the scope of its basic group and it determines precisely the topic field that is considered to be the most appropriate one for carrying out the search. One or more dots are placed before the subgroup text, which determine its subordination degree, that is, they indicate to the fact that the subgroup is the heading subordinated to the nearest higher-level heading printed with a smaller shift, that is, having one dot less.

For example,   A01B 1/02 .spades; shovels

A01B 1/04 ..with teeth

Currently, having the scope of the patent publications grown up to 3 million publications per year, it is impossible to imagine carrying out the search in the patent databases without such classification criterion, which puts each technical solution on its “shelf.”

One can get acquainted with the content of the IPC and its Guidance on the website of Rospatent.

However, some countries, in particular, the USA and Japan, have been still classifying their patent documentation in accordance with the National Patent Classification (NPC), and the IPC is used as an additional one.

The USPS (United States Patent Classification) is the National Patent Classification (NPC) of the USA.

The NPC of the USA was established in 1836. It is based on a functional and branch principle. The methods and devices performing the same functions that manufacture the same products or achieve the same effect are combined. The main division in the classification is the class. In turn, the classes are subdivided into subclasses. The classification index is denoted by the Arabic digits and it consists of two numbers separated by a dash.

The NPC of the USA is used for the classification of the inventions, the industrial designs and the plants of the USA, and it is used for the search of the patent documents of the USA in the following search systems: PatFT: Patents и AppFT: Applications;  Global Patent Index;PatSearch.

FI (FI Section / Broad-Facet Selection) and F-term (F-term Group of Theme Selection) are the National Patent Classifications (NPCs) of Japan (Patent Map Guidance).

Japan has two National Patent Classifications, FI and F-term.

FI is based on the IPC and it includes its extensions in the fields that are the most popular ones in Japan; it consists of the IPC indexes, which are supplemented by digital characters.

F-term being an original system of the classification of the inventions of Japan was introduced in 1948. F-term is a “facet” (“multi-facet”) classification, with the help of which the subject matter of the invention is classified from the different points of view simultaneously (a material, a shape, a preparation, an application, etc.). The main steps of the division are the class, the subclass and the group. The classes are denoted by the Arabic digits, the subclasses are denoted by the capital letters of the Latin alphabet, the groups are denoted by the Arabic digits using a decimal principle.

The classifications are used to index the inventions and the utility models of Japan and they are applied for the search of the patent documents of Japan in the following search systems: The Industrial Property Digital Library (IPDL); Global Patent Index; PatSearch.

Access to the above search systems can be obtained on the websites of the above patent offices or in the All-Russian Patent and Technical Library.

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