1975^ gives explanations of the U.S. codes. Figure 2 shows a typical 

 page from the manual. The U.S. Patent Office has available lists of all 

 patent numbers presently referenced to each U.S. classification code by 

 original or cross-reference classification. 



The names of the inventor's attorney and the U.S. Patent Office ex- 

 aminer who reviewed the application are included in the patent, along 

 with information on closely related patents discovered in their search. 

 The number, date of issue, inventor, and original classification code of 

 these patents are listed. Most patents issued since October 1970 also 

 have a list of the classifications searched for the review. 



Inventors make revisions to patents by having them reissued. Reis- 

 sued patents are assigned reference numbers preceded by the abbreviation 

 "Re." in a sequence separate from the original patents. The complete 

 text of the original patent is in the reissue with deletions in brackets 

 and additions in italics. 



The format of patents was changed in 1970 to streamline the search 

 process and prepare the documents for inclusion in a computer processable 

 library. All of the above information, an abstract, and an exemplary 

 figure are on the first page of the patent document as shown in Figure 1 . 

 Each data element on the page is identified with an internationally 

 recognized numeric code for worldwide use of the information. 



III. FINDING PATENTS 



Complete copies of all patents in the CERC collection are filed in 

 numerical order in bound reference volumes in the CERC library. At the 

 U.S. Patent Office Public Search Room, Crystal Plaza, 2221 Jefferson 

 Davis Boulevard, Arlington, Virginia, all issued patents are filed both 

 on microfilm in numerical order and in printed copies under their as- 

 signed classification codes [original or cross-reference) . Table 2 lists 

 the libraries in the United States that have patent collections open to 

 the public. Copies of patents may be ordered by patent number for 50 

 #ents apiece (1979) by writing the Commissioner of Patents and Trade- 

 marks, Washington, D.C. 20231. 



Several methods of finding patents in desirable categories are avail- 

 able to the searcher. Patent attorneys and examiners with access to the 

 Public Search Room commonly use guides to the patent classification sys- 

 tem to pick the classification codes covering the types of inventions 

 desired, then directly search the files under those codes. If the sole 

 available collection is filed only in numerical order, the searcher ob- 

 tains the Patent Office's lists of patent numbers assigned the chosen 

 codes. Searchers who must keep a current record of patents in a partic- 

 ular technical field can subscribe to the OfjHcial Gazette (Department 



2DEPARTr4ENT OF COMMERCE, PATENT AND TRADEMARK OFFICE, Manual of Clas- 

 sification of Patents, U.S. Government Printing Office, Washington, D.C, 

 1975 (Updated to 1979) . 



I I 



