On April 29, 1913, Swedish-American electrical engineer Gideon Sundback was granted U.S. Patent No. 1,219,881 for an improved separable fastener—what came to be recognized as the basis for the modern zipper. Sundback’s design refined earlier attempts at an automatic fastener by arranging individual metal teeth on facing tapes and shaping them so that the slider would interlock and separate them reliably. The improvement solved key durability and usability problems that limited earlier designs from the 1890s and early 1900s. Background The idea of a mechanical clothing fastener predates Sundback. French engineer Elias Howe received a patent in 1851 for an “automatic continuous clothing closure” but did not commercialize it. In the 1890s Whitcomb Judson developed and marketed a “clasp locker” for shoes; it reached only limited success because the mechanism was bulky and often unreliable. Judson’s company and early machines advanced public awareness of the concept, but the closures were not yet the practical, mass-producible device clothing manufacturers needed. Sundback’s contribution Gideon Sundback, working for the Universal Fastener Company in Hoboken, New Jersey, built on prior work and practical manufacturing needs. His 1913 patent described a series of U-shaped metal clips hinged to a cloth tape and a slider that meshed and unmeshed the elements. Crucially, Sundback’s teeth were designed to interlock precisely and the slider guided them into alignment, creating a smoother, stronger closure. He also developed improvements in manufacturing machinery that made mass production of the fastener feasible. Reception and adoption Initially, the fastener was used in specialized applications. In the 1910s and 1920s, manufacturers began using Sundback’s fasteners for boots and tobacco pouches; during World War I, they were adopted for some military gear, which helped demonstrate the device’s utility. The name “zipper” itself came later: in the 1920s the B.F. Goodrich Company used Sundback-style fasteners on a type of rubber boot and marketed them as “Zippers,” and the term gradually entered general use. Legacy Sundback’s patent and related manufacturing innovations shifted the fastener from a curiosity to an industrially viable product. Over subsequent decades, materials and designs evolved—brass, nickel, and later plastic teeth; improved sliders; and different tape materials—but the fundamental principle Sundback patented—interlocking fed elements guided by a slider—remained central. Zippers became ubiquitous in clothing, luggage, and industrial applications worldwide, profoundly affecting garment design and everyday convenience. Notes on sources and attribution The central fact that U.S. Patent No. 1,219,881 was granted to Gideon Sundback on April 29, 1913, is documented in U.S. patent records. Historical accounts place Sundback’s work in continuity with earlier inventors such as Elias Howe and Whitcomb Judson; Sundback’s improvements are widely cited as decisive in producing a practical, mass-producible fastener. Some details about the pace and pathways of adoption vary among sources, and the popular term “zipper” emerged from commercial branding rather than from the patent itself.