Chapter Table of Contents
A. Mandatory Classifications
By determining the proper classification designation of each claim in a patent separately, and then assigning each separate classification designation to the patent, you can be reasonably certain that the claimed subject matter contained in the patent is retrievable. Each such classification is a mandatory classification. The Original classification (OR) is selected from among the mandatory classifications as being the highest in the schedule (superiority) of the class containing the controlling claim (see Section IV, A, above). The remaining mandatory classifications are designated as cross-references (XR) and the patent documents are so labeled.
Also designated as cross-references are any number of additional classifications that are deemed appropriate by the classifier or examiner, within the guidelines set forth below. These cross-references may provide for disclosure not encompassed by the claims or for claimed subject matter that may be useful in classifications other than the mandatory classifications determined by the placement procedures in Section V. The question of what unclaimed subject matter should be cross-referenced, and where, must be left to the judgment of the classifier or the examiner familiar with the art. Since there is a presumption that unclaimed subject matter is not new, it may be of little value. However, this is not always true, and much of this subject matter should be cross-referenced to make it available to a searcher. There are no exact rules. When, in the judgment of the classifier or examiner, the subject matter is useful and is disclosed in sufficient detail and clarity to be used as a reference, it should be cross-referenced.
1. Cross-References to Any Part of System
Unfamiliar subject matter should not be ignored. If a specific composition, electrical circuit, joint support, etc., is disclosed, it should not be assumed that it is conventional or not useful merely because it is not claimed. A classifier or examiner having experience in such unfamiliar art should be consulted to determine if a discretionary cross-reference would be useful.
2. Cross-Referenced Subject Matter Should Fit Subclass Definition
Subject matter cross-referenced to a subclass should fit the definition of the subclass.
However, since the ultimate objective is to aid the searcher, a large amount of discretion may be used.
In creating the USPC system, several techniques have been used to limit the need for discretionary cross-referencing. These consist of (1) proper positioning of subclasses in a class schedule and (2) search notes.
a. Cross-Referencing Between Classes
A search note in the class definition of each of related classes generally precludes the need for discretionary cross-referencing. However, as in all discretionary cross-referencing, there may be a time when it is desirable to cross-reference even if there is cross noting. For example, if a claim is classified in a combination class, it may be desirable to cross reference it to the subcombination class even if the locations are cross noted. A patent classified in a class providing for a subcombination (e.g., a machine tool chuck) should not necessarily be cross-referenced to a combination class (e.g., machine tool) solely on the basis of the subcombination.
b. Cross-Referencing Between Subclasses
The following general considerations apply to the placement of discretionary cross-references:
- When two subclasses (either in the same or separate classes) contain subject matter related in structure or mode of operation but which are separated on different functional bases, the provision of a search note in each subclass referring to the other subclass generally precludes cross-referencing from either subclass to the other.
- Two coordinate subclasses may have a combination-subcombination relationship with the subcombination subclass title consisting of the identical terminology of a portion of the combination subclass title or a subclass indented thereunder. If a search note is provided in the subcombination subclass indicating that the combination subclass or the subclass indented thereunder must be searched when conducting a search for the subcombination, then no cross-references are made from the combination subclass, or subclass indented thereunder, to the subcombination. However, a disclosure of a combination in a patent placed in the subcombination subclass may be cross-referenced if it is believed to be useful.
- When two coordinate subclasses have a genus-species relationship (the species subclass appearing first in the schedule), generally no cross-reference of such species is made to the genus subclass.
- When there are two subclasses, the first of which contains a great number of patents having disclosures directed to subject matter which could be cross-referenced to the second subclass but which fact is not evident from the titles of the subclasses, a search note is generally provided in the definition of the second subclass indicating that the first subclass must be searched and no patents are cross-referenced from the first subclass to the second subclass.
- Generally, no cross-reference is made within a class when the relative schedule position of the subclasses involved indicates that a search for the disclosure would include both subclasses.
In each of the above situations, it is quite common to find one or two cross-references, irrespective of the presence of a search note. Classifiers frequently do this to alert a searcher who may have overlooked the search note to a pertinent field of search.
c. Cross-Referencing Between a Parent Subclass and Its Indents
The two most frequent types of relationship between a parent subclass and subclasses indented under it are (a) combination-subcombination and (b) genus-species.
(1) In a subclass array including a parent subclass and indented subclasses of the type involving the combination-subcombination relationship-that is, where the indented subclass is directed to subject matter of the parent subclass combined with an additional feature or with a perfecting feature-a claim to the combination will be placed, as original, in the indented subclass directed to the first claimed feature. If the claim also recites an unprovided for additional feature or perfecting feature, the claim may, by discretion, be cross-referenced in the parent subclass.
(2) In a subclass array including a parent subclass and indented subclasses of the type involving the genus-species relationship -i.e., where the parent subclass is directed to a genus and an indented subclass is directed to a species-a claim to the species provided for in the indent and to an un-provided for species is classified originally in the parent subclass and cross-referenced in the indented subclass.
d. Search Notes in a Subclass Do Not Preclude Cross-Referencing in Its Indents
A note in a first subclass may indicate that a second subclass should be searched in connection with a search for the subject matter of the first subclass. This does not preclude cross-referencing of a patent from the second subclass to a subclass indented under the first subclass and directed to a specific variant thereof.
Only U.S. patent grants classified with "original" (OR) classifications in a subclass are accorded evidential value to construe titles, definitions, and notes of the subclass. This is because discretionary cross-references often reflect a great deal of subjective judgment on the part of an examiner or classifier, and there is no distinction made between mandatory and discretionary cross-references in the labeling of patent documents. Thus, for the purpose of (a) resolving differences as to placement of a patent application or a patent or (b) demonstrating separate classifications or divergent fields of search in an examiner's requirement for restriction, only patents placed as ORs may be cited. There is no difference at all, with respect to reference value in an Examiner's action, between an OR and XR patent.