B21L MAKING METAL CHAINS
Introduced: September 1968
Classification Context
- Section:
- PERFORMING OPERATIONS; TRANSPORTING
- Class:
- MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- Subclass:
- MAKING METAL CHAINS
Description
B21L covers mechanical processes and machinery for manufacturing metal chains without substantial material removal. This subclass encompasses chain fabrication methods including welding, forming, and assembling of chain links, along with associated equipment such as linking machines, welding apparatus, and quality control devices. Typical applications include production of conveyor chains, lifting chains, and decorative chains from ferrous and non-ferrous metals. Excluded are drawing operations for wire or rod preparation (covered under B21B) and operations that involve significant material removal such as cutting or grinding of finished chain components.
Filing statistics
IPC subclass B21L recorded 2,434 patent applications worldwide between 2013 and 2023. Annual filings grew from 138 in 2013 to 225 in 2023 (+63%), peaking at 354 applications in 2020. The most active applicants in class B21 are JFE STEEL (2,318 applications), JFE STEEL (2,294 applications) and POSCO (POHANG IRON AND STEEL COMPANY) (2,083 applications).
Source: EPO PATSTAT, worldwide filings
In class comparison
B21L ranks 8th of 9 subclasses with filings in B21, with 2,434 applications between 2013 and 2023, 0.4% of the class. Annual filings grew 63% from 2013 to 2023, below the class as a whole (+146%).
| Rank | Subclass | Title | Applications | Share |
|---|---|---|---|---|
| 1 | B21D, Working or Processing of Sheet Metal or Metal Tubes, Rods or Profiles Without Essentially Removing Material; Punching Metal | Working or Processing of Sheet Metal or Metal Tubes, Rods or Profiles Without Essentially Removing Material; Punching Metal | 351,007 | 53.1% |
| 2 | B21C, Manufacture of Metal Sheets, Wire, Rods, Tubes, Profiles or Like Semi-Manufactured Products Otherwise Than by Rolling; Auxiliary Operations Used in Connection With Metal-Working Without Essentially Removing Material | Manufacture of Metal Sheets, Wire, Rods, Tubes, Profiles or Like Semi-Manufactured Products Otherwise Than by Rolling; Auxiliary Operations Used in Connection With Metal-Working Without Essentially Removing Material | 84,269 | 12.8% |
| 3 | B21B, Rolling of Metal | Rolling of Metal | 71,906 | 10.9% |
| 4 | B21F, Working or Processing of Metal Wire | Working or Processing of Metal Wire | 67,229 | 10.2% |
| 5 | B21J, Forging; Hammering; Pressing Metal; Riveting; Forge Furnaces | Forging; Hammering; Pressing Metal; Riveting; Forge Furnaces | 53,883 | 8.2% |
| 6 | B21K, Making Forged or Pressed Metal Products, e.g. Horse-Shoes, Rivets, Bolts or Wheels | Making Forged or Pressed Metal Products, e.g. Horse-Shoes, Rivets, Bolts or Wheels | 18,766 | 2.8% |
| 7 | B21H, Making Particular Metal Objects by Rolling, e.g. Screws, Wheels, Rings, Barrels, Balls | Making Particular Metal Objects by Rolling, e.g. Screws, Wheels, Rings, Barrels, Balls | 9,223 | 1.4% |
| 8 | B21L | Making Metal Chains | 2,434 | 0.4% |
| 9 | B21G, Making Needles, Pins or Nails of Metal | Making Needles, Pins or Nails of Metal | 1,702 | 0.3% |
Source: EPO PATSTAT, worldwide filings
Related Keywords
11 direct subcodes
Child Classifications
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- B21L 1/00 Making chains or chain links by bending workpieces of rod, wire, or strip to form links of oval or other simple shape
- B21L 11/00 Making chains or chain links of special shape
- B21L 13/00 Making terminal or intermediate chain links of special shape; Making couplings for chains, e.g. swivels, shackles
- B21L 15/00 Finishing or dressing chains or chain links, e.g. removing burr material, calibrating
- B21L 19/00 Appurtenances for chain-making not restricted to any particular process
- B21L 21/00 Tools or implements for repairing chains using metal-working operations, e.g. for detaching deformed chain links
- B21L 3/00 Making chains or chain links by bending the chain links or link parts and subsequently welding or soldering the abutting ends
- B21L 5/00 Making chains or chain links by working the starting material in such a way that integral, i.e. jointless, chain links are formed
- B21L 7/00 Making chains or chain links by cutting single loops or loop-parts from coils, assembling the cut parts and subsequently subjecting same to twisting with or without welding
- B21L 9/00 Making chains or chain links, the links being composed of two or more different parts, e.g. drive chains
- B21L 99/00 Subject matter not provided for in other groups of this subclass
Top Applicants
Top 10 applicants by patent filingsfor class B21, 2013–2023, worldwide · Source: EPO PATSTAT
- JFE STEEL 2,318
- JFE STEEL JP 2,294
- POSCO (POHANG IRON AND STEEL COMPANY) KR 2,083
- NIPPON STEEL CORPORATION JP 1,650
- NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 1,631
- SMS GROUP DE 1,472
- BAOSHAN IRON & STEEL COMPANY 1,181
- SGCC(STATE GRID CORPORATION OF CHINA) 1,079
- ANHUI JIANGHUAI AUTOMOBILE 984
- HYUNDAI STEEL COMPANY KR 980