Classification

Browse US Patents by Subject Classification

Patents are filed into subject classes so that related inventions sit together regardless of the words used to describe them. Two schemes matter here: the Cooperative Patent Classification used today, and the older United States Patent Classification it replaced.

Cooperative Patent Classification (CPC)

CPC is the scheme in current use, developed jointly by the USPTO and the European Patent Office. It splits all of technology into nine sections, each subdivided down to fine-grained groups. A code such as B64C29/0008 reads as section B, class 64, subclass C, then the specific group.

The section pages below collect every patent in the archive carrying a code in that section.

United States Patent Classification (USPC)

USPC was the national scheme used for well over a century before CPC replaced it for most purposes. Its classes are plain numbers — class 604 is Surgery, class 181 is Acoustics — and a great deal of older literature, citation and cross-reference still refers to patents by their USPC class.

The class pages below carry the official class definition, so that a reference to a USPC class encountered elsewhere can still be resolved.

CPC sections

8 sections

A — Human Necessities

Human necessities. The broadest section by everyday reach: agriculture and animal husbandry, foodstuffs and tobacco, personal and domestic articles from clothing to furniture, and the whole of medical and veterinary science — preparations, devices, hygiene and life-saving equipment. If an invention is used on or by a person rather than on a material or a machine, it usually lands here.

46 patents

B — Performing Operations and Transporting

Performing operations and transporting. Covers the actions industry performs on things: separating and mixing, shaping metal and plastics, printing, and the whole of transport — land vehicles, railways, ships, aircraft — together with packaging, handling of thin material, and micro- and nano-structural technology. The unifying idea is a process or a machine acting on something, rather than the substance acted upon.

41 patents

C — Chemistry and Metallurgy

Chemistry and metallurgy. Inorganic and organic chemistry, compositions, dyes, petroleum, fermentation and biochemistry including genetic engineering, alongside metallurgy, alloys and the treatment of metal surfaces. Where section B claims the apparatus that performs a process, section C generally claims the substance and the chemical route to it.

33 patents

D — Textiles and Paper

Textiles and paper. Covers natural and artificial threads and yarns, spinning and twisting, weaving, braiding, lace-making and knitting, trimmings and non-woven fabrics, ropes and cables, and the chemical and mechanical treatment of textile materials — alongside the making of paper, cellulose and board and the machinery used for it. A small section by volume, and an unusually mechanical one: most filings describe a machine or a discrete process step rather than a material, which is what separates it from the chemistry of section C. Papermaking sits here rather than in C for the same reason — the claimed invention is normally the apparatus or the process, not the pulp.

4 patents

E — Fixed Constructions

Fixed constructions. Covers building in the widest sense: foundations, walls, floors and roofs, doors, windows and stairs, locks and safes, scaffolding and formwork, and sanitary and water-supply installations — together with earth and rock drilling, mining, tunnelling and shaft sinking, and hydraulic engineering such as dams, canals, locks and coastal protection. What unites an otherwise disparate section is that the subject matter stays where it is built. That is the line against the transport section, where the same mechanical principles appear in something designed to move, and against section F, where a comparable machine is not tied to a site.

4 patents

F — Mechanical Engineering, Lighting and Heating

Mechanical engineering, lighting, heating, weapons and blasting. Engines and pumps of every kind, general engineering elements such as bearings, springs, valves and gearing, lighting and heating apparatus, refrigeration, steam generation, and weapons and ammunition. A large and deliberately mixed section, held together by mechanism rather than by application.

28 patents

G — Physics

Physics. Instruments and their use: measuring and testing, optics, photography, horology, signalling, computing and data processing, information storage, and nucleonics. This is where software-implemented inventions are generally classified, which makes it one of the most heavily populated sections in modern filings.

111 patents

H — Electricity

Electricity. Basic electric elements such as cables, resistors, semiconductor devices and batteries; the generation, conversion and distribution of electric power; and electronic circuitry and communication technique, including transmission, telephony and broadcasting. Section G measures and computes; section H generates, carries and switches.

75 patents

USPC classes

14 classes

Class 181 — Acoustics Devices for producing, transmitting, damping, or absorbing sound, including mufflers and silencers. Broadly equivalent modern CPC coverage sits in section F (Mechanical Engineering, Lighting and Heating).
Class 206 — Special Receptacle or Package Receptacles and packages distinguished by contents, structure, or method of packaging. Broadly equivalent modern CPC coverage sits in section B (Performing Operations and Transporting).
Class 221 — Article Dispensing Machines and devices for dispensing discrete articles from a supply. Broadly equivalent modern CPC coverage sits in section B (Performing Operations and Transporting).
Class 330 — Amplifiers Electrical amplifiers and amplifying systems, including their control and coupling arrangements. Broadly equivalent modern CPC coverage sits in section H (Electricity).
Class 362 — Illumination Light sources, luminaires, and systems for producing and directing artificial light. Broadly equivalent modern CPC coverage sits in section F (Mechanical Engineering, Lighting and Heating).
Class 367 — Communications, Electrical: Acoustic Wave Systems and Devices Sonar, echo ranging, seismic surveying, and related acoustic wave apparatus. Broadly equivalent modern CPC coverage sits in section G (Physics).
Class 384 — Bearings Bearings and bearing assemblies, including their lubrication, sealing, and mounting. Broadly equivalent modern CPC coverage sits in section F (Mechanical Engineering, Lighting and Heating).
Class 424 — Drug, Bio-Affecting and Body Treating Compositions Compositions for treating the human or animal body, including their preparation and use. Broadly equivalent modern CPC coverage sits in section A (Human Necessities).
Class 604 — Surgery Instruments and methods for introducing material into, or removing material from, the body. Broadly equivalent modern CPC coverage sits in section A (Human Necessities).
Class 623 — Prosthesis Artificial body parts and implants, including their attachment and fitting. Broadly equivalent modern CPC coverage sits in section A (Human Necessities).
Class 705 — Data Processing: Financial, Business Practice, Management, or Cost/Price Determination Automated systems for commercial transactions, business methods, and resource management. Broadly equivalent modern CPC coverage sits in section G (Physics).
Class 968 — Horology Timepieces and time-measuring apparatus, including their movements and regulation. Broadly equivalent modern CPC coverage sits in section G (Physics).
Class 977 — Nanotechnology Structures and processes involving matter at dimensions below one hundred nanometres. Broadly equivalent modern CPC coverage sits in section B (Performing Operations and Transporting).
Class PLT — Plants Plant patents: distinct and new varieties of plant reproduced asexually, other than tuber-propagated plants and plants found in an uncultivated state.