The Classification of Patents

by United States. Patent Office

In this schedule the miscellaneous subclass is numbered 1, then follow three subclasses (2-4) of rolling plus another function, then four major subclasses (5-16) of rolling, merely, but applied to blanks of special form producing special products, then one special subclass (17) based upon a special class of material treated, then five subclasses (18-31) specialized in type and mode of operation, then general types of rolling mills (32-40), then various parts and accessories (41-59), then processes (60-66). This is the usual arrangement and is an exhaustive division for the art of metal rolling. Had there been miscellaneous subclasses for all combined operations of rolling plus some other function, a miscellaneous subclass for all mere rolling machines, either special or general, and a miscellaneous subclass for all parts and accessories, the requirements of exhaustive division would have been also satisfied.

In the illustrative schedule, there being no miscellaneous subclass for means having combined functions of rolling and another, any patent having claims for the combination of a means for rolling and a means for cooling would fall in subclass 1, Miscellaneous. In that subclass would also fall all "Mills," such as for rolling spiral conveyer-flights, the same not falling under any of the subclasses 32-40, no miscellaneous subclass of "Mills" and no special article-rolling subclass having been provided; also all parts or accessories, such as a water-cooled screen, peculiarly adapted to rolling-mills, there being no existing subclass of screens therein and no miscellaneous subclass of parts. The arrangement of subclasses in Class 80 requires that the combination of a furnace and a rolling-mill shall be placed in subclass 2, even if the combination be designed and adapted for rolling annular bodies (subclass 5) or tubes (subclass 11). Means special to rolling a tube between a concave and roll must be placed in subclass[p. 29] 13 rather than in subclass 18. A work-reversing mill must be placed in subclass 33 rather than in subclass 34 even though it have three or more coacting rolls.

The rolling of "Screw-threads" having been given higher rank than a "Concave and roll" mechanism, any concave and roll mechanism limited for use in rolling screw-threads should be formed into a subclass indented under "Screw-threads" and not into a subclass "Screw-threads" indented under "Concave and roll."

(10) Class schedules are arranged with certain subclasses appropriately indented according to a commonly understood expedient. In a properly indented schedule subclasses in column at the extreme left are the main species (the proximate species) of the class. The titles and definitions of all subclasses proximate to the class (at extreme left) must be read with the title and definition of the class, as if indented under the class title one space to the right; so also with the titles and definitions of subclasses indented under other subclasses. If a title has no number (as in Class 80, "Mills"), it represents merely a subject-matter to be divided, assumed to have no representatives other than those in the species indented under it. If a title having indented species under it has a number, it not only represents a subject to be divided but also a subclass including all other species not falling within the indented titles. Indention does not indicate superiority or inferiority, but merely that the title and the definition of the indented subclass must be read with the title and definition of the subclass under which it is indented. A title selected in a scheme of subdivision to be of first importance and placed, therefore, in advance, should not thereafter be indented under a title selected to be of secondary importance and, therefore, having a lower position. (See Rule [8].)

(11) A group of material may be divided on several different bases. "Use" or "purpose" or "object treated" may be adopted only when the "use" or "purpose" or "object treated" stamps upon the invention such peculiarities of operation or construction as to limit the applicability of the invention to the use or purpose named. (See Basis of Classification, Rule [1].) A group based upon mode of operation also may be divided into subclasses (1) with a "functional" title, usually participial in form, and adapted therefore to receive machines, processes, and tools; (2) with special use, purpose, or object-treated title containing the name of the use, purpose, or object; (3) with "type" title, usually a name or a name with a qualifying adjective; (4) with a title of a part or subcombination, also a name.

Example: In Class 90, Gear-Cutting, Milling, and Planing, are to be found subclasses entitled "Gear-cutting," certain machines being peculiar to that use; also other subclasses with the general functional title "Planing," subordinate to which are the special use subclass "Planing, Soft metal," and the type subclass "Planers" divided into two coordinate subclasses, "Reciprocating bed" and "Reciprocating cutter," and several subordinate "part" subclasses, including "Tool-feeds" and[p. 30] "Tool-heads." The adjective form of the title "Planers, Reciprocating bed," indicates a type subclass. If the title had been Planers, Reciprocating beds, the indication would be that the subclass was a part subclass to receive planer beds only. In the class referred to for illustration, "Tool-feeds" and "Tool-heads" indicate subclasses for parts and not for types of planers having tool feeds.

(12) In arranging the divisions of a class, such arrangement should be sought as will minimize the need of cross-references. Search for any particular matter can not always be limited to one group without such extensive cross-referencing as would in some cases defeat the purpose of classification. Forming the subdivisions of a class according to the total similarities of the inventions, rather than according to some selected more or less important characteristic, and arranging them in the correct order of superiority and inferiority, with care to maintain throughout the schedule the relative positional values of the several selected bases of division, will ordinarily in a closely bonded class limit the search for any single invention to the subclass particularly suited to receive it and some subclasses preceding that one, excluding from the necessity of search the subclasses succeeding.

Example: In Class 80, Metal-Rolling, it would not be expected to find any tube-rolling mill lower in the schedule than the tube-rolling subclasses, but a tube-mill might be found higher up in "Heating and rolling," "Drawing and rolling," etc. No concave and roll combination should be found succeeding the subclass of "Concave and roll," but it may be found under subclasses above, such as "Tubes, Screw-threads," etc. No rolls should be found lower than the subclass of "Rolls," but they may be found in many subclasses above.

DEFINITION.

(13) Having some knowledge of the nature of the materials about to be classified, a tentative definition of a class to be formed may be framed, which may be either written down or merely carried in mind, to serve as a tentative guide. This tentative definition must be considered as subject to change to any extent by the fuller knowledge obtained by careful consideration of the material. After a full knowledge of the materials to be classified has been acquired, it will be necessary to frame a careful definition of the class, and also of each subclass whose title does not unequivocally indicate what is contained in it.