Zipper Types – Hook and Eye
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. 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.
Interlocking Teeth Model
Gideon Sundback, a Swedish-born Canadian 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.
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 Yoshida Kagya Kabushiki-gaisha 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.
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.
Over a number of years the they has become extremely common on many of the clothing items that are worn by everyday people all over the world.
Coil Zippers now form the bulk of sales of zippers worldwide. The slider runs on two coils on each side; the teeth are the coils. Two basic types of coils are used: one with coils in spiral form, usually with a cord running inside the coils; the other with coils in ladder form, also called the Ruhrmann type. This second type is now used only in a few parts of the world, mainly in South Asia. Coil zippers are made of polyester coil and are thus also known as polyester zippers. Nylon was formerly used and though only polyester is used now, the type is still known as a nylon zipper.
Invisible Zippers teeth are behind the tape. The tape’s color matches the garment’s, as does the slider, so that, except the slider, the zipper is invisible. This kind is common in skirts and dresses. Invisible zippers are usually coil zippers.
Metallic Zipper are the classic zipper type, found mostly in jeans today. The teeth are not a coil, but are individual pieces of metal moulded into shape and set on the zipper tape at regular intervals. Metal zippers are made in brass, aluminium and nickel, according to the metal used for teeth making. All these zippers are basically made from flat wire. A special type of metal zipper is made from pre-formed wire, usually brass but sometimes other metals too. Only a few companies in the world have the technology. These type of pre-formed metal zippers are mainly used in high grade jeanswear, workwear, etc., where high strength is required and zippers need to withstand tough washing.
Plastic Moulded Zipper are identical to metallic zippers, except that the teeth are plastic instead of metal. Metal zippers can be painted to match the surrounding fabric; plastic zippers can be made in any color of plastic. Plastic zippers mostly use polyacetal resin though other resins are used too like polyethylene.
Open-ended Zippers use a box and pin mechanism to lock the two sides of the zipper into place, often in jackets. Open-ended zippers can be of any of the above specified types.
Closed-ended Zipper are closed at both ends; they are often used in baggage.
Japan makes 90% of the world’s zippers. A large part of these are manufactured by YKK, which has production facilities in 68 countries and the world’s largest zipper manufacturing center in Macon, Georgia USA, with 900 employees. Almost all of the rest are made in Southeast Asia. Major zipper manufacturing countries in Southeast Asia are now Bangladesh, China, India and Pakistan. These countries are not only manufacturing zippers for domestic use and use in exported products but are exporting zippers directly to other countries as well.