National Zipper Day

National Zipper Day, observed on April 29th, marks the anniversary of the 1913 patent filing by Swedish-American engineer Gideon Sundback for the modern zipper design, originally called the "separable fastener." While earlier fastening devices had been patented by inventors including Elias Howe and Whitcomb Judson in the 19th century, those early designs were unreliable and prone to jamming or splitting open, limiting their practical adoption. Sundback, working as an engineer for the Universal Fastener Company, significantly refined the design by increasing the number of fastening elements per inch and creating a more reliable interlocking tooth mechanism guided by a sliding tab, essentially establishing the basic mechanical design still used in zippers today. Despite this improved design, the zipper took decades to achieve widespread commercial adoption, initially finding use mainly in boots and tobacco pouches, since clothing manufacturers and the general public remained hesitant to trust the fastener. The B.F. Goodrich Company is credited with coining the name "zipper" in 1923 for the sound the device made, using it for a new line of rubber boots. The fashion industry's acceptance of zippers accelerated significantly in the 1930s as designers began incorporating them into clothing, including children's clothing marketed for its ease of use, eventually establishing the zipper as a ubiquitous fastening technology used in clothing, bags, and countless other products worldwide.