4.2.2.2.1 Common Rule

Also in this Chapter:

• 4.2.2.2.1 Common Rule
• 4.2.2.2.2 First Place Priority Rule

• 4.2.2.2.3 Last Place Priority Rule

• 4.2.2.2.4 Special Rules

• 4.2.2.2.5 Classifying a Combination of Technical Subjects

The common rule is the default classification rule in the IPC/CPC and it is applied in all areas of the IPC/CPC, unless specified otherwise.

The common rule is based on the principle of devising the classification in such a way that the same technical subject can be classified in one and the same place in the Classification. This principle assumes that classification places in the IPC are mutually exclusive.

Example (hypothetical):

• Inventive subject matter: characterised by both Wind and Chemical energy
• Relevant CPC scheme:

A (1/00) main group

• A1(1/02) Electrical energy
• A2(1/04) Wind energy
• A3(1/06) Solar energy
• A4(1/08) Chemical energy
• When the common rule is applied, the invention should be classified under both A2 and A4.

Classification should be made in all appropriate places. However, the following principles of priority can be applied to limit unnecessary multiple classification and to select groups that most adequately represent the technical subject to be classified:

a) Groups for more complex matter take priority over groups for less complex matter. For example, groups for combinations take priority over groups for sub-combinations and groups for “whole things” take priority over groups for “details”

b) Groups for more specialised subject matter take priority over groups for less specialised subject matter. For example, groups for unique types of matter or groups for matter with means for solving particular problems take priority over more general groups.