Gear case
bicycle chain or belt enclosure to protect the rider from getting dirty or getting clothes stuck in the driveline
A gear case, also known as a chain case or chain guard, is a protective enclosure for the bicycle's chain and sprocket assemblies. Its primary function is to protect the cyclist from being soiled or trapped in the chain rings while also protecting the chain from dirt and moisture. Gear cases may fully or partially enclose the drivetrain and sometimes incorporate an oil bath for continuous lubrication. Modern examples are usually moulded in plastic. Although they are also used by some touring bicycles as well as some chain-drive machinery, chain cases are most frequently found on utility bicycles.
History
From the 1880s until the 1970s, bicycle chain cases were typically made from metal or varnished cloth. These materials provided protection against dirt and damage, with metal cases offering greater durability but increased weight and production cost.
In the mid-20th century, Willemine Johanna van der Woerd (née Looijen), director of the De Woerd bicycle accessory factory, improved the design of cloth chain cases. On 25 July 1959, she filed a patent for a closure for a chain case in which the seam had alternating open hooks. A wire could be zigzagged through these hooks to close the case, providing a closure that was easy to open and close while remaining under proper tension.
This brief starts where responsible research should: with the source description of “Gear case” as bicycle chain or belt enclosure to protect the rider from getting dirty or getting clothes stuck in the driveline. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the general reference register because the source frames it as bicycle chain or belt enclosure to protect the rider from getting dirty or getting clothes stuck in the driveline. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Oct 30, 2025. The linked authority identifier is Q1467873. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1959.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
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This entry incorporates text from “Gear case” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.