Class 260 , the class of organic chemistry, once contained the largest array of patent documents in the PTO. It was decided that this class needed to be reclassified because its concepts did not necessarily address new technology and several of its subclasses were too difficult to search because of their size.
Also, it was decided that a new format for reclassification should be adopted so that the results of reclassification projects could be used as soon as possible. In the past, a class was reclassified in its entirety; however, it is not practical to reclassify a large class like 260 in its entirety because it could take years before a newly created class and its subclasses could be published.
Consequently, the decision was made to segment Class 260 into a number of individual reclassification projects so that the results of these projects would be available for searches. Using this approach has resulted in the publication of several individual classes, within the range of Classes 518-585 , to replace subclasses and concepts found in Class 260. Whenever subclasses are replaced in Class 260, the individual subclass areas are noted by a reference box in Class 260 to indicate the new search areas. Eventually, all of Class 260 will be reclassified and Class 260 will be abolished. Within the range of Classes 518-585, Classes 520-528 are considered the 520 series and Classes 532-570 are considered another series. Each of Classes 518-585 is considered an independent class under the Class 260 umbrella.
Within the newly established classes, the schedule hierarchy and placement superiority are indicated by the class number. For instance, Class 525 is superior to Class 528 and Class 544 is superior to Class 560. The Class numbers merely indicate superiority of subject matter within the Class 260 family. Each class in the 520 Series and in the 532-570 series has been noted by upper case characters followed by a one-dot indent level with a carryover on the top of the manual page indicating the appropriate series¾ i.e., 520, 532-570. The general rules of patent placement in Section V, B, 1, of this handbook apply to the 520 and 532-570 series.