Zippers with common teeth variations: metal teeth (top), coil teeth and plastic teeth.
A zipper, zip, fly, or zip fastener, formerly known as a clasp locker, is a commonly used device for binding the edges of an opening of fabric or other flexible material, such as on a garment or a bag. 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 items. Zippers come in all different sizes, shapes, and colors. Whitcomb L. Judson was an American inventor from Chicago who invented and constructed a workable zipper. The method, still in use today, is based on interlocking teeth. Initially, it was titled the “hookless fastener” and was later redesigned to become more reliable.Contents
The bulk of a zipper/zip consists of two rows of protruding teeth, which may be made to interdigitate, linking the rows, carrying from tens to 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 the slider's movement. The word Zipper is onomatopoetic, because it was named for the sound the device makes when used, a high-pitched zip.Examples of special zippers with different tape materials, colors and patterns.
In many jackets and similar garments, the opening is closed completely when the slider is at the top end. Some jackets have double-separating zippers with two sliders on the tape. When the sliders are on opposite ends of the tape then the jacket is closed. If the lower slider is raised then the bottom part of the jacket may be opened to allow more comfortable sitting or bicycling. When both sliders are lowered then the zipper may be totally separated.
Bags, suitcases and other pieces of luggage also often feature two sliders on the tape: the part of the zipper between them is unfastened. When the two sliders are located next to each other, which can be at any point along the tape, the zipper is fully closed.A two-way (double-separating) 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 fall 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. With separating zippers, the insertion pin may tear loose from the tape; the tape may even disintegrate from use. If a zipper fails, it can either jam (i.e. get stuck) or partially break off.History
In 1851, Elias Howe received a patent for an "Automatic, Continuous Clothing Closure". He did not try seriously to market it, missing recognition he might otherwise have received. Howe's device was more like an elaborate drawstring than a true slide fastener.
Forty-two years later, in 1893 Whitcomb Judson, who invented a pneumatic street railway, marketed a "Clasp Locker". The device served as a (more complicated) hook-and-eye shoe fastener. With the support of businessman Colonel Lewis Walker, Judson launched the Universal Fastener Company to manufacture the new device. The clasp locker had its public debut at the 1893 Chicago World's Fair and met with little commercial success. Judson is sometimes given credit as the inventor of the zipper, but he never made a practical device.
The company, reorganized as the Fastener Manufacturing and Machine Company, moved to Hoboken, N.J. in 1901. Gideon Sundback, a Swedish-American electrical engineer, was hired to work for the company in 1906. Good technical skills and a marriage to the plant-manager's daughter Elvira Aronson led Sundback to the position of head designer. The company moved to Meadville, PA, where it operated for most of the 20th century under the name Talon, Inc. Sundback worked on improving the fastener and in 1909 he registered a patent in Germany. The US-rights to this invention were on the name of the Meadville company (operating as the Hookless Fastener Co.), but Sundback retained non-U.S. rights and used these to set up in subsequent years the Canadian firm Lightning Fastner Co. in St. Catharines, Ont. Sundback's work with this firm has led to the common misperception that he was Canadian and that the zipper originated in that country.
Gideon Sundback increased the number of fastening elements from four per inch (about one every 6.4 mm) to ten or eleven (around every 2.5 mm), introduced two facing rows of teeth that pulled into a single piece by the slider, and increased the opening for the teeth guided by the slider. The patent for the "Separable Fastener" was issued in 1917. Gideon Sundback also created the manufacturing machine for the new device. The "S-L" or "scrapless" machine took a special Y-shaped wire and cut scoops from it, then punched the scoop dimple and nib, and clamped each scoop on a cloth tape to produce a continuous zipper chain. Within the first year of operation, Sundback's machinery was producing a few hundred feet (around 100 meters) of fastener per day. In March of the same year, Mathieu Burri, a Swiss inventor, improved the design by adding a lock-in system attached to the last teeth, but his version never got into production due to conflicting patents.
In 1923 during a trip to Europe Sundback sold his European rights to the Swiss Martin Othmar Winterhalter who improved the design by using ribs and grooves instead of Sundback's joints and jaws  and started producing with his Riri-company on large scale first in Germany, then in Switzerland.Zipper slider brings together the two sides
The popular North American term zipper, (UK zip, or occasionally zip-fastener), came from the B. F. Goodrich Company in 1923. The company opted to use Gideon Sundback's fastener on a new type of rubber boots (or galoshes) and referred to it as the zipper, and the name stuck. The two chief uses of the zipper in its early years were for closing boots and tobacco pouches. Zippers began being used for clothing in 1925 by Schott NYC on leather jackets.
In the 1930s, a sales campaign began for children's clothing featuring zippers. The campaign praised zippers for promoting self-reliance in young children by making it possible for them to dress in self-help clothing. The zipper beat the button in 1937 in the "Battle of the Fly", after French fashion designers raved over zippers in men's trousers. Esquire declared the zipper the "Newest Tailoring Idea for Men" and among the zippered fly's many virtues was that it would exclude "The Possibility of Unintentional and Embarrassing Disarray."
The most recent innovation in the zipper's design was the introduction of models that could open on both ends, as on jackets. Today the zipper is by far the most widespread fastener, and is found on clothing, luggage, leather goods, and various other objects.Types A coil zipper with its slider removed.
Airtight zippers were first developed by NASA for making high-altitude pressure suits and later space suits, capable of retaining air pressure inside the suit in the vacuum of space.
The airtight zipper is built like a standard toothed zipper, but with a waterproof sheeting (which is made of fabric-reinforced polyethylene and is bonded to the rest of the suit) wrapped around the outside of each row of zipper teeth. When the zipper is closed, the two facing sides of the plastic sheeting are squeezed tightly against one another (between the C-shaped clips) both above and below the zipper teeth, forming a double seal.
This double-mated surface is good at retaining both vacuum and pressure, but the fit must be very tight, to press the surfaces together firmly. Consequently, these zippers are typically very stiff when zipped shut and have minimal flex or stretch. They are hard to open and close because the zipper anvil must bend apart teeth that are being held under tension. They can also be derailed (and damage the sealing surfaces) if the teeth are misaligned while straining to pull the zipper shut.
These zippers are very common where airtight or watertight seals are needed, such as on scuba diving dry suits, ocean survival suits, and hazmat suits.
A less common water-resistant zipper is similar in construction to a standard toothed zipper, but includes a molded plastic ridge seal similar to the mating surfaces on a ziploc bag. Such a zipper is easier to open and close than a clipped version, and the slider has a gap above the zipper teeth for separating the ridge seal. This seal is structurally weak against internal pressure, and can be separated by pressure within the sealed container pushing outward on the ridges, which simply flex and spread apart, potentially allowing air or liquid entry through the spread-open ridges. Ridge-sealed zippers are sometimes used on lower-cost surface dry suits.Anti-slide zipper locks
Some zippers include a designed ability for the slider to hold in a steady open or closed position, resisting forces that would try to move the slider and open the zipper unexpectedly. There are two commons ways this is accomplished:
The zipper handle can have a short protruding pin stamped into it, which inserts between the zipper teeth through a hole on the slider, when the handle is folded down flat against the zipper teeth. This appears on some brands of trousers. The handle of the fly zipper is folded flat against the teeth when it is not in use, and the handle is held down by both slider hinge tension and the fabric flap over the fly.
The slider can also have a two-piece hinge assembly attaching the handle to the slider, with the base of the hinge under spring tension and with protruding pins on the bottom that insert between the zipper teeth. To move the zipper, the handle is pulled outward against spring tension, lifting the pins out from between the teeth as the slider moves. When the handle is released the pins automatically engage between the zipper teeth again. They are called "auto-lock sliders".
A three-piece version of the above uses a tiny pivoting arm held under tension inside the hinge. Pulling on the handle from any direction lifts the pivoting arm's pins out of the zipper teeth so that the slider can move.Components Components of a zipper Different types of zipper pullers and sliders.
The components of a zipper are:
Forbes reported in 2003 that although the zipper market in the 1960s was dominated by Talon Zipper (USA) and Optilon (Germany), Japanese manufacturer YKK grew to become the industry giant by the 1980s. YKK held 45 percent of world market share, followed by Optilon (8 percent) and Talon Zipper (7 percent).
Indian Tex Corp has also emerged as a significant supplier to the apparel industry.
In Europe, Cremalleras Rubi company established in 1926 in Catalonia, continues to compete with the big multinationals selling over 30 million zippers in 2012.
In 2005, The Guardian reported that China had 80 percent of the international market. Most of its product is made in Qiaotou, Yongjia County.Patents
Zippers have entered into urban legends. American folklorist Jan Brunvand noted that "The zipper has been the subject of jokes and legends since... the 1920s". Those stories reflect "modern anxieties and desires", emphasizing embarrassments and accidents, primarily involving the flies of men's trousers in stories such as "The Unzipped Stranger" and "The Unzipped Fly".Durability and repairs
The zipper is often the least durable component in any garment or type of equipment. Most often the zipper fails to close due to a worn or bent slider not being able to apply the necessary force to the sides of the teeth to cause them to interlock. This problem can sometimes be redressed by using small pliers to carefully squeeze the back part of the slider together a fraction of a millimeter. This can compensate for the wear of the slider. The slider is typically made as a magnesium diecast which breaks easily. It is necessary to reduce the force on the pliers before it can be felt that the slider actually gives in. If it is not yet possible to successfully close the zipper, the pressure applied to the slider should only gradually be increased. Another way to reduce the gap of the open end of the slider is by preparing a small block of wood by sawing a slot into one end so that it fits over the upper arm of the slider. Then a hammer can be used to exact a force onto the slider by carefully hitting the wood.
When the protective coating of the diecast slider has been worn off by prolonged usage, the material can corrode. The corrosion products are usually metal salts which can accumulate and block the slider from moving. When this happens the salt can often be dissolved by submerging the slider in vinegar or another mild acid. Otherwise the slider needs to be removed and replaced.See also