The first step to classifying a document in CPC is to identify the subject matter that will be classified. The second step is to identify appropriate groups in CPC covering the subject matter to be classified.
The general rules for identifying the subject matter to classify in CPC are as follows:
- (A) All subject matter covered by the claims of a patent document must be classified as invention information along with any novel and unobvious constituents or components (subcombinations) of the claimed subject matter. Classification should be based on the subject matter of each claim as a whole and on each inventive embodiment within a claim.
- (B) Any unclaimed subject matter in the disclosure that is novel and unobvious must also be classified as invention information.
- (C) It is desirable to classify or index any additional information complementing the invention information, mentioned in the claims or in the unclaimed disclosure, if it is useful for search purposes.
- (D) A subcombination of the subject of the invention if the subcombination is itself novel and non-obvious.
The scheme or definitions in particular areas should be consulted to determine if additional classification or index codes are required. For example, places in CPC where multi-aspect classification is especially desirable are indicated by a note. See MPEP § 905.02. Depending on the nature of the subject matter concerned, such a note prescribes obligatory classification of the subject matter according to the indicated aspects, or contains a recommendation for multi-aspect classification if it is desirable for increasing the efficiency of the patent search.
The general procedure for identifying the appropriate groups for covering the subject matter to be classified is as follows:
- (A) Identify the appropriate subclasses covering the subject matter to be classified.
- (1) The scope of a subclass is defined by its title and definition. In order to determine a candidate subclass for classification one must review the titles of available subclasses for scope coverage.
- (2) After a candidate subclass has been identified, the subclass notes, references and definition should be consulted to verify that the scope of the subclass covers the subject matter to be classified.
- (3) The preceding steps should be repeated until a candidate subclass is verified to cover the subject matter to be classified.
- (B) Identify the appropriate group(s) covering the subject matter to be classified.
- (1) Identify candidate main groups that cover the subject matter to be classified.
- (2) Verify that the notes, references, and definitions do not exclude the subject matter to be classified, and that the group is in active use (not under reclassification).
The technical subject matter of many inventions is completely covered by only one group in the subclass. In this situation, classification is made in the one group covering the technical subject matter of the invention.
When multiple groups cover the technical subject matter of a single invention, classification is generally made in the group which most completely covers the invention. Within a group array, a group that covers the technical subject matter of the invention to be classified generally covers the subject matter more completely than the parent of that group.
When multiple groups cover the invention equally well, groups are selected according to the following rules:
- (a) In the case where the Last Place Priority Rule (LPPR) is applicable to the groups under consideration, then the group lowest in the scheme is selected for classification.
- (b) In the case where the First Place Priority Rule (FPPR) is applicable to the groups under consideration, then the group highest in the scheme is selected for classification.
- (c) In the case where neither LPPR nor FPPR are applicable to the groups under consideration, then classification is made in each group.
- (3) Whenever classifying into a group, the scheme notes and definitions should be consulted for guidance regarding special rules of classification applicable to the CPC groups at issue, such as the requirement for Multiple Aspect classification or Indexing.
- (4) Whenever classifying into a group, the scheme should always be consulted for precedence notes and references that indicate a preference for classification in another group. Precedence notes and limiting reference should always be followed when applicable.
- (5) Identify application/functional classification places. Occasionally, two or more subclasses/groups are identified that cover the disclosed invention information from different aspects. For example, one classification place might cover specific uses of the invention, whereas the second classification place may cover the generic uses of the invention. These types of coverage are respectively referred to as application and functional classification places. In general, classification is made in the application classification place when application specific adaptations are disclosed. For example, a pump specially adapted to replace a heart is classified in A61M 1/10, whereas pumps, in general, without any disclosed special adaptation are classified in F04B, F04C, F04D, or F04F depending on the specific structure of the pump. When uses of inventions are nominally disclosed, classification is generally made in functional classification places.
- (6) Identify genus/species classification places.
- (a) In the case where an invention is generically disclosed classification is made to the classification place covering the generic invention. Even in cases where species are nominally disclosed, such as by name only, classification is still made to the generic classification place.
- (b) In the case where fully enabled species are disclosed, classification is required in the classification places covering the individual species.
- (7) Identify residual classification places
In the event a classification place that explicitly covers the technical features of the invention to be classified cannot be identified, then classification should be made to a “residual” classification place. Residual classification places can be found at both subclass and group levels. Residual classification places are identifiable by their titles, which typically indicate they cover subject matter not elsewhere covered.