Velcro

From Wikipedia, the free encyclopedia

Velcro is a brand name of fabric hook-and-loop fasteners.^[1] It consists of two layers: a "hook" side, which is a piece of fabric covered with tiny hooks, and a "loop" side, which is covered with even smaller and "hairier" loops. When the two sides are pressed together, the hooks catch in the loops and hold the pieces together.^[2] When the layers are separated, the strips make a characteristic "ripping" sound.

Velcro hook and loop fasteners can be made of many things—the first sample was made of cotton, which proved to be impractical.^[3] Nylon and polyester^[4] are the fibers most commonly used now. Velcro fasteners made of Teflon loops, polyester hooks, and glass backing is used on space shuttles.^[4]

There are variations on the standard Velcro hook and loop fasteners: one of which, for example, includes hooks on both sides. However these are not common. Alternatives to Velcro brand fasteners are buttons, zippers, laces and buckles.

George de Mestral named his invention "Velcro", which is a portmanteau of the two French words velours, meaning 'velvet', and crochet, or 'hook'.^[5][6][1] The term Velcro is a registered trademark in most countries. Generic terminology for these fasteners includes "hook and loop", "burr" and "touch" fasteners. The Velcro company headquarters is in Manchester, New Hampshire, USA.

Contents 1 History 2 Strength 3 Advantages and disadvantages 4 Applications 4.1 Hook and loop jumping 5 Hook and loop in popular culture 6 See also 7 References 8 External links

[edit] History

The hook-loop fastener was invented in 1941 by Swiss engineer, George de Mestral^[5][7][8] who lived in Commugny, Switzerland. The idea came to him one day after returning from a hunting trip with his dog in the Alps. He took a close look at the burrs (seeds) of burdock that kept sticking to his clothes and his dog's fur. He examined them under a microscope, and noted their hundreds of "hooks" that caught on anything with a loop, such as clothing, animal fur, or hair. ^[3] He saw the possibility of binding two materials reversibly in a simple fashion,^[8] if he could figure out how to duplicate the hooks and loops.^[5]

Originally people refused to take him, and the idea, seriously when he took his idea to Lyon, which was then a center of weaving. He did manage to gain the help of one weaver, who made two cotton strips that worked. However the cotton wore out quickly, so de Mestral turned to synthetic fibers.^[3] He settled on nylon as being the best synthetic, which had several advantages. Nylon doesn’t break down, rot, or attract mold, and it could be produced in threads of various thickness.^[4] Nylon had only recently been invented, and through trial and error he eventually discovered that, when sewn under hot infrared light, nylon forms hooks that were perfect for the hook side of the fastener.^[5] Though he had figured out how to make the hooks, he had yet to figure out a way to mechanize the process, and to make the looped side. Next he found that nylon thread, when woven in loops and heat-treated, retains its shape and is resilient, however the loops had to be cut in just the right spot so that they could be fastened and unfastened many times. On the verge of giving up, a new idea came to him. He bought a pair of shears and trimmed the tops off the loops, thus creating hooks that would match up perfectly with the loops.^[3]

Mechanizing the process of weaving the hooks took eight years, and it took another year to create the loom that trimmed the loops after weaving them. In all, it took ten years to create a mechanized process that worked.^[3] He submitted his idea for patent in Switzerland in 1951 and the patent was granted in 1955.^[5] Within a few years he had gotten patents and began to open shop in Germany, Switzerland, Great Britain, Sweden, Italy, the Netherlands, Belgium, and Canada. In 1957 he branched out to the textile center of Manchester, New Hampshire in the United States. Columnist Sylvia Porter made the first mention of the product in her column Your Money's Worth of August 25, 1958, writing "It is with understandable enthusiasm that I give you today an exclusive report on this news: A 'zipperless zipper' has been invented—-finally. The new fastening device— which is on my desk as I type this, and which I have been opening and closing, opening and closing for days— is in many ways potentially more revolutionary than was the zipper a quarter century ago."^[9] A Montreal firm, Velek, Ltd., acquired the exclusive right to market the product in North and South America, as well as in Japan, with American Velcro, Inc. of New Hampshire, and Velcro Sales of New York, marketing the "zipperless zipper" in the United States.^[10]

De Mestral got patents in many countries right after inventing Velcro fasteners as he expected a high demand immediately. Partly due to its appearance though, hook and loop's integration into the textile industry took time. At the time, hook and loop looked like it had been made from left-over bits of cheap fabric, and thus was not sewn into clothing or used widely when it debuted in the early 1960s.^[11] It was also viewed as impractical.^[11]

Velcro fasteners got their first break when they were used in the aerospace industry to help astronauts maneuver in and out of bulky space suits. However, this reinforced the view among the populace that hook and loop was something with a very limited utilitarian uses. The next major use hook and loop saw was with skiers, who saw the similarities between their costume and the astronauts, and thus saw the advantages of a suit that was easier to get in and out of. Scuba and marine gear followed soon after. After seeing astronauts storing food pouches on walls^[12] and stand upright in the weightless atmosphere with the aid of hook and loop, children's clothing makers came onboard.^[11] As hook and loop only became widely used after NASA's adoption of it, NASA is popularly credited with the invention of hook and loop.

Later improvements included strengthening the filament by adding polyester.^[4]

In 1978 de Mestral's patent expired, prompting the flood of low-cost imitations from Taiwan, China and South Korea onto the market. Today, the trademark is the subject of more than 300 trademark registrations in over 159 countries.^[specify] George de Mestral was inducted into the national inventors hall of fame for his invention.^[3] He once offered some advice to Velcro executives:

"If any of your employees ask for a two-week holiday to go hunting, say yes."

The big breakthrough George de Mestral made was to think about hooks and eyes on a greatly reduced scale. Hook and eye fasteners have been around for centuries, but what was new about Velcro fasteners was the scale of the hooks and eyes. Shrinking the hooks led to the two other important differences. Firstly, instead of a single file line of hooks, Velcro fasteners have a two dimensional surface.^[13] This was needed because in decreasing the size of the hooks, the strength was also unavoidably lessened, thus requiring more hooks for the same strength. The other difference is that Velcro fasteners have indeterminate matchup between the hooks and eyes. With larger hook and eye fasteners, each hook has its own eye. On a scale as small as that of hook and loop, matching up each of these hooks with the corresponding eye is impractical, thus leading to the indeterminate matching.^[13]

[edit] Strength

Hook and loop is surprisingly strong. A two inch square piece of hook and loop is enough to support a 175 pounds (79 kg) person.^[11] The strength of the bond depends on how well the hooks are embedded in the loops, how much surface area is in contact with the hooks, and the nature of the force pulling it apart. If hook and loop is used to bond two rigid surfaces, e.g. auto body panels and frame, the bond is particularly strong because any force pulling the pieces apart is spread evenly across all hooks. Also, any force pushing the pieces together is disproportionally applied to engaging more hooks and loops. Vibration can cause rigid pieces to improve their bond. Full-body hook and loop suits have been made that can hold a person to a suitably covered wall.

When one or both of the pieces is flexible, e.g. a pocket flap, the pieces can be pulled apart with a peeling action that applies the force to relatively few hooks at a time. If a flexible piece is pulled in a direction parallel to the plane of the hook and loop surface, then the force is spread evenly as it is with rigid pieces.

Three ways to maximize the strength of a bond between the two flexible pieces are:

• increase the area of the bond, e.g. using larger pieces of hook and loop
• ensure that the force is applied parallel to the plane of the fastener surface, e.g. bending around a corner or pulley.
• increase the number of hooks and loops per area unit

Shoe closures can resist a large force with only a small amount of hook and loop. This is because the strap is wrapped through a slot, which halves the force on the bond by acting as a pulley system and getting a mechanical advantage, and which ensures that the force is parallel to the hook and loop strips.

[edit] Advantages and disadvantages

In favor of hook and loop, it is easy to use, safe, and maintenance free. There is only a minimal decline in effectiveness even after many fastening and unfastenings. The tearing noise it makes can also be useful against pickpockets.^{[citation needed]} Additionally, in the United States Air Force, where hook and loop is used to attach patches to flight suits, aircrew have learned that they can remove small cloth pile balls that accumulate on the suits by using the hook side on the back of the patches like a brush to remove them.

Hook and loop has several deficiencies: it tends to accumulate hair, dust, and fur in its hooks after a few months of regular use. The loops can become elongated or broken after extended use. Hook and loop often becomes attached to articles of clothing, especially loosely woven items like sweaters. Additionally, the clothing may be damaged when one attempts to remove the hook and loop, even if they are separated slowly. The tearing noise made by unfastening hook and loop makes it inappropriate for some applications. For example, a soldier hiding from the enemy would not want to alert the enemy to his or her position by opening a hook and loop pocket.^[5] It also absorbs moisture and perspiration when worn next to the skin, which means it will smell if not washed.
Textiles can contain chemicals or compounds, e.g. dyes, ^[14] that may be allergenic to sensitive populations. Velcro products have been tested according to the Oeko-tex certification standard which imposes limits on the chemical content of textiles to address the issue of human ecological safety.

[edit] Applications

Because it is easy to use, maintenance free and safe, the hook-and-loop fasteners have been used for just about every conceivable application where a temporary bond is required. It is especially popular in clothing where it replaces buttons or zippers, and as a shoe fastener for children who have not yet learned to tie shoelaces and for those who choose hook and loop over laces. Hook and loop is used in adaptive clothing, which is clothing designed for people with physical disabilities, the elderly, and the infirm who may experience difficulty dressing themselves due to an inability to manipulate closures, such as buttons and zippers. As hook and loop is easier to manipulate, it makes a good replacement.

Hook and loop held together a human heart during the first artificial heart surgery, and it is used in nuclear power plants and army tanks to hold flashlights to walls. Cars use it to bond headliners, floor mats and speaker covers. It is used in the home when pleating draperies, holding carpets in place and attaching upholstery, among many other things.^[3] It closes backpacks, briefcases and Trapper Keepers, secures pockets and holds disposable diapers on babies. It is an integral part of the game tag rugby, is used in surfboard leashes and orthopaedic braces.

NASA is a big user of hook and loop. Each space shuttle has ten thousand inches of a special hook and loop made of Teflon loops, polyester hooks, and glass backing.^[4] Hook and loop is used everywhere, from the astronauts' suits, to anchoring equipment. In the near weightless conditions in orbit, hook and loop is used to temporarily hold objects and keep them from floating away.^[15] A hook and loop patch is used inside astronauts' helmets where it serves as a nose scratcher.^[3][4] During mealtimes astronauts use trays that attach to their thighs using spring and hook and loop fasteners.^[12]

The US Army is another big user. It uses hook and loop fasteners on combat uniforms to attach name tapes, rank insignia, shoulder pockets for unit patches, skill tabs, and recognition devices, such as the infrared (IR) feedback American flag. They also had a silent version of hook and loop developed for use with Army soldier uniforms, as the ripping sound could betray a soldier's position. A new version was created which reduced the noise by over 95%. The manufacturing process to create this noiseless hook and loop is, however, a military secret.^[4]

There have been some failed uses for hook and loop as well. One such failure was a worm collar that consisted of a cylindrical strip that fishers were supposed to slip over their live bait. The hook and loop was supposed to snag in the teeth of striking bass. Another failure was a strap-on device for impotent men.^[4]

[edit] Hook and loop jumping

Hook and loop jumping is a sport where people wearing hook and loop covered suits take a running jump and hurl themselves as high as possible at a hook and loop covered wall.^[4][16] The wall is inflated, and looks similar to other inflatable structures. It is not necessarily completely covered in hook and loop—often there will be vertical strips of hook and loop. Sometimes, instead of a running jump, people use a small trampoline.

David Letterman immortalized this during the Feb 28, 1984 episode of Late Night with David Letterman on NBC. David Letterman proved that with enough hook and loop a man could be hurled against a wall and stick, by performing this feat himself on TV.^[3][11][16] This put hook and loop in the national spotlight.^[11]

Hook and loop jumping goes beyond David Letterman though. Amusement companies rent hook and loop walls and jumpsuits for 400-500 dollars a day.^[16] It was also done on a regular basis in pubs in both New York and New Zealand, where it is a competition to see how high a person can get their feet above the ground.^[17] Jeremy Bayliss and Graeme Smith of the Cri Bar and Grill in Napier, New Zealand, started it after seeing American astronauts velcroed to walls during space flights. They created their own equipment for the "human fly" contests, and sold it to several others in New Zealand.^[17]

The sport moved to the US after Sports Illustrated ran a story on it in 1991. Adam Powers and Stephen Wastell of the Perfect Tommy's bar in New York city read of the sport, and soon became the United States distributor of Human Bar Fly equipment. Hook and loop wall-jumping now exists in dozens of New Zealand bars and is said to be one of the favorite bar activities there (outside of the steady consumption of alcohol).^[17]

[edit] Hook and loop in popular culture

Lists of miscellaneous information should be avoided. Please relocate any relevant information into appropriate sections or articles. (October 2008)

Hook and loop has worked its way into popular culture and common knowledge. As such, it has been part of many movies, and mentioned in songs and television shows. In 2001: A Space Odyssey flight attendants on commercial spacecraft wear hook and loop soled slippers to keep themselves attached to the deck; on Star Trek hook and loop was used to attach phasers and communicators to the uniform belts or trousers, although it was never named as such. In the 1996 John Frankenheimer film The Island of Dr. Moreau, Moreau's assistant jokingly claims that the doctor won his Nobel Prize for inventing hook and loop. ^[18]

Hook and loop has become part of a recurring joke in various media in which it is claimed that modern humans would be unable to invent it, and that it is in fact a form of advanced technology. For example, K claims in Men in Black that hook and loop was originally alien technology,^[19] and part of the plot of the 2002 Star Trek Enterprise episode "Carbon Creek", features hook and loop as being given to modern society by crash-landed Vulcans in 1957. (Also one of the Vulcan characters in this episode was named Mestral in tribute to the name of hook and loop's real-life inventor, George de Mestral.)^[20] More recently one of the characters in the 2004 film Garden State made a vast fortune from inventing silent velcro.^[21]

[edit] See also

• Mr Velcro Fastener
• Velcro dog
• Velcro Fly
• Adaptive clothing
• Biomimicry

[edit] References

[edit] External links

Look up velcro in Wiktionary, the free dictionary.

• Velcro Official US company website
• closeup of Velcro hooks and loops
• VELCRO USA INC. Celebrates 50TH
• VELCRO Patent - from Google Patents Anniversary
• Adhesives Guide by Velcro USA - Adhesive Guide by Velcro USA

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