A zipper (English: zip fastener or zip) is a popular device for temporarily joining two edges of fabric. It is used in clothing (e.g. jackets and jeans), luggage and other bags, sporting goods, camping gear (e.g., tents and sleeping bags), and other daily use items, because it's stronger than the alternatives.
The bulk of a zipper consists of two strips of fabric tape, each affixed to one of the two pieces to be joined, carrying tens or hundreds of specially shaped metal or plastic teeth. These teeth can be either individual or shaped from a continuous coil, and are also referred to as elements. The slider, operated by hand, moves along the rows of teeth. Inside the slider is a Y-shaped channel that meshes together or separates the opposing rows of teeth, depending on the direction of its movement. The friction and vibration of the slider against the teeth causes a characteristic buzzing noise, which is probably the origin of the name zipper. The name also may have originated in the greater speed and ease with which the two sides of a zipper can be joined, compared to the time needed for fastening laces or buttons.
Some zippers have two slides, allowing variation in the opening's size and position. In most jackets and similar garments, the opening is closed entirely when one slide is at each end. In most baggage, the opening is closed entirely when the two slides are next to each other at any point along the zipper.
These variations are achieved by sewing one end of the zipper together, sewing both ends together, or allowing both ends of the zipper to come completely apart.
A zipper costs relatively little, but if it fails, the garment may be unusable until the zipper is repaired or replaced -- which can be quite difficult and expensive. Problems often lie with the zipper slider; when it becomes worn it does not properly align and join the alternating teeth.
An early device superficially similar to the zipper, "an Automatic, Continuous Clothing Closure", was patented in the United States by Elias Howe in 1851. Unlike the zipper, Howe's invention had no slider; instead a series of clasps slid freely along both edges to be joined, with each clasp holding the two sides together at whichever pair of points along them it was located. The clasps were joined together by a string, which, when pulled taut, caused the clasps to be evenly spaced along the closure, thus holding the two edges together. Pulling in the other direction caused the clasps to become bunched up at one end, by which means the device was opened.
The true zipper was the product of a series of incremental improvements over more than twenty years, by inventors and engineers associated with a sequence of companies that were the progenitors of Talon, Inc. This process began with a version called the "clasp locker", invented by Whitcomb L. Judson of Chicago (previously of Minneapolis and New York City), and for which a patent was first applied on Nov. 7, 1891. It culminated in 1914 with Gideon Sundback's invention of the "Hookless Fastener No. 2", the first version of the zipper without any major design flaws and essentially indistinguishable from modern zippers.
Initial versions of the zipper were based on the "hook and eye" principle, rather than on interlocking teeth, and tended to come apart easily. Some versions depended on constant pressure from one side of the joined fabric in order to hold together at all, which limited applications. In the 1891 version, the slider detached entirely from the zipper when not being used to open or close.
Judson, together with business partner Harry Earle, founded the first incarnation of what was to eventually become Talon Inc., in Chicago in 1894, as the Universal Fastener Company. The design deficiencies, combined with difficulties in getting the machinery needed for mass production to work, prevented the early devices from reaching market, which led to financial hardships for the company. This in turn led to a series of reorganizations and name changes, as well as relocations, first to Catasauqua, Pennsylvania; then to Elyria, Ohio; Hoboken, New Jersey; and finally Meadville, Pennsylvania.
Gideon Sundbäck, a Swedish-born American immigrant, joined the company, then called the Automatic Hook and Eye Company, in Hoboken, in 1906. At that time the company's product, still based on hooks and eyes, was called the "C-curity Fastener". Sundback developed an improved version of the C-curity, called the "Plako", but it too had a strong tendency to pull apart, and wasn't any more successful than the previous versions. Sundback finally solved the pulling-apart problem in 1913, with his invention of the first version of the zipper based on interlocking teeth, the "Hookless Fastener No. 1".
That version, however, had a tendency to wear out quickly, and again was not a commercial success. Finally, in 1914 Sundback developed another version based on interlocking teeth, the "Hookless No. 2", which solved the last remaining major design defect, and opened the way to commercial success. The principle is, each tooth is punched to have a dimple on its bottom and a nib or conical projection on its top. The nib atop one tooth engages in the matching dimple in the bottom of the tooth that follows it on the other side as the two strips of teeth are brought together through the two Y channels of the slider. The teeth are crimped tightly to a strong fabric cord that is the selvage edge of the cloth tape that attaches the zipper to the garment, with the teeth on one side offset by half a tooth's height from those on the other side's tape. They are held so tightly to the cord and tape that once meshed there is not enough play to let them pull apart - - a tooth cannot rise up off the nib below it enough to break free, and its nib on top cannot drop out of the dimple in the tooth above it. The classic zipper was made of a brass alloy, a metal that has low friction and is long-wearing.
Sundback's invention of the Hookless No. 2 took place while he was working for the Hookless Fastener Company in Meadville, which had previously been set up to manufacture the Hookless No. 1. Depending on which improvement one wants to consider to constitute the "invention" of the zipper, the zipper was invented either in Meadville, Chicago, or one of the other previously mentioned cities. The B. F. Goodrich Company coined the name Zipper in 1923 for the line of rubber overshoes that it made using the fastener. The name slowly came to be associated with the fastener itself, and eventually acquired generic status.
The zipper slowly became popular for children's clothing and men's trousers in the 1920s and 1930s. In the early 1930s the haute couture designer Elsa Schiaparelli featured zippers in her avant-garde gowns, helping it to become acceptable in women's clothing. In 1934, Tadao Yoshida founded a company called San-S Shokai in downtown Tokyo. Later, this company would change its name to YKK and become the world's largest manufacturer of zippers and fastening products. By World War II, the zipper had become widely used in Europe and North America, and after the war quickly spread through the rest of the world.
Clergy in the 1920s and 1930s described zippers as allowing one to take one's clothes off too quickly, thus hastening illicit sexual activity. Clothing with zippers was seen as inappropriate to be worn by women because of this belief, and was not fully adopted until the late 1950s.
Today, such global companies as YKK, Olympic Zippers Ltd, Opti, TALON, Ideal, NEO, KCC Group, and Tex Corp, make various types of zippers including "invisible" zippers, metallic zippers, and plastic zippers.
On a CBC-produced miniseries aired in January 2007, The Greatest Canadian Invention; the Zipper placed at No. 8 on the list. It qualified because Sundback had been president of a Canadian-based company that was one of the earliest manufacturers of the zipper.
Over a number of years the zipper has become extremely common on many of the clothing items that are worn by everyday people all over the world.
The components of a zipper are: