UNITED STATES PATENT AND TRADEMARK OFFICE PATENT CLASSIFICATION SYSTEM

http://www.uspto.gov

Three major classifications for utility patents:
(1) General and Mechanical - Examples
• Class 137 Fluid Handling
• Class 198 Conveyors: Power-Driven
• Class 297 Chairs and Seats

(2) Chemical - Examples
• Class 260 Chemistry of Carbon Compounds
• Class 435 Chemistry: Molecular Biology and Microbiology

(3) Electrical - Examples
• Class 363 Electric Power Conversion Systems
• Class 369 Dynamic Information Storage or Retrieval
• Class 455 Telecommunications

Index to the U.S. Patent Classification System http://www.uspto.gov/web/patents/classification/uspcindex/indextouspc.htm

Manual of Patent Classification
http://www.uspto.gov/web/patents/classification/