Miscellaneous Definitions — accessories, trims, tools and general fashion terms from Apparel Search
Velcro is a brand name of fabric hook-and-loop fasteners used for connecting objects. It was invented in 1948 by George de Mestral, a Swiss engineer, after he examined the seed pod burrs that kept sticking to his dog on their daily walk in the Alps. De Mestral named the invention from the French words velours, meaning velvet, and crochet, meaning hook. Velcro consists of two layers: a hook side covered with tiny plastic hooks and a loop side covered in equally tiny plastic loops. Pressed together, the hooks catch in the loops and hold; pulled apart, the strips make a telltale ripping sound.
Velcro is a brand name of fabric hook-and-loop fasteners used for connecting objects.
Velcro was invented in 1948 by George de Mestral, a Swiss engineer. The idea came to him after he took a close look at the seed pod burrs which kept sticking to his dog on their daily walk in the Alps. De Mestral named his invention after the French words velours, meaning 'velvet', and crochet, meaning 'hook'.
Velcro consists of two layers: a "hook" side, which is a piece of fabric covered with tiny plastic hooks, and a "loop" side, which is covered in equally tiny plastic loops. When the two sides are pressed together, the hooks catch in the loops and hold the pieces together. When the layers are separated, the Velcro strips makes a telltale ripping sound. Since the name Velcro is a registered trademark, generic implementations often use the name "hook and loop", though in common usage, "velcro" is used generically.
The strength of the Velcro bond depends on how well the hooks are embedded in the loops and the nature of the force pulling it apart. If Velcro 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.
When one or both of the pieces is flexible, e.g. a pocket flap, the pieces can be pulled apart with a peeling action which applies the force to relatively few hooks at a time. If a flexible piece is pulled parallel to the plane of the velcro surface the force is spread evenly like with rigid pieces.
There are three ways to maximise the strength of a Velcro bond with one or more flexible pieces:
ensure that the force is applied parallel to the plane of the Velcro surface, e.g. bending around a corner or pulley.
increase the area of the Velcro bond, e.g. long purse straps.
use a pulley system, e.g. shoe closures.
Shoe closures can resist a large force with little bonding area by wrapping a strap through a slot which reduces the force on the Velcro by ensuring the force is parallel to the plane of the Velcro and by halving the force on the Velcro bond by acting as a pulley system.
Velcro has several deficiencies: it tends to accumulate hair, dust, and fur in its hooks after a few months of regular use and the loops can become elongated or broken. It 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 Velcro, even if they are separated slowly. The tearing noise made by unfastening Velcro makes it inappropriate for some applications, but is useful against pickpocketing.
The strength of a Velcro bond depends on how much surface area is in contact with the Velcro hooks: full-body Velcro suits have been made that can hold a person to a Velcro-covered wall.
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The above article is licensed under the GNU Free Documentation License. From Wikipedia, the free encyclopedia (https://en.wikipedia.org/wiki/velcro). 10/25/04 |
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How the Hook-and-Loop Fastener WorksVelcro consists of two layers that do opposite jobs. The hook side is a piece of fabric covered with tiny plastic hooks, and the loop side is covered in equally tiny plastic loops. When the two sides are pressed together, the hooks catch in the loops and hold the pieces together across the whole contact area, not at a single point like a button or snap. When the layers are separated, the strips make a telltale ripping sound as the hooks pull free. That distributed grip copies the burr that inspired De Mestral in 1948: many small hooks engaging at once. The strength of the bond depends on how well the hooks are embedded in the loops and on the nature of the force pulling it apart. With two rigid surfaces, such as auto body panels and frame, the bond is particularly strong because force pulling the pieces apart is spread evenly across all hooks, and force pushing them together disproportionately engages more hooks and loops; vibration can even improve the bond. At full contact the strength is considerable: full-body Velcro suits have been made that can hold a person to a Velcro-covered wall. Peeling, Shear, and Making a Bond StrongerFlexible pieces behave differently. When one or both pieces is flexible, such as a pocket flap, the pieces can be pulled apart with a peeling action that applies force to relatively few hooks at a time, so the fastener opens progressively and easily. If a flexible piece is pulled parallel to the plane of the Velcro surface, by contrast, the force is spread evenly as with rigid pieces and the bond resists far more strongly. There are three ways to maximise the strength of a bond with one or more flexible pieces: ensure the force is applied parallel to the plane of the surface, for example by bending around a corner or pulley; increase the area of the bond, for example with long purse straps; and use a pulley system, as shoe closures do. Limitations of Hook-and-Loop FastenersVelcro has several deficiencies. It tends to accumulate hair, dust and fur in its hooks after a few months of regular use, and the loops can become elongated or broken. It often becomes attached to clothing, especially loosely woven items like sweaters, and clothing may be damaged when it is removed. The tearing noise makes it inappropriate for some applications, though it is useful against pickpocketing. The US Army has had the Velcro company investigating a silent version for use with Army soldier uniforms. Common QuestionsWho invented Velcro and when?Velcro was invented in 1948 by George de Mestral, a Swiss engineer. The idea came after he took a close look at the seed pod burrs that kept sticking to his dog on walks in the Alps. What does the name Velcro mean?De Mestral named his invention after the French words velours, meaning velvet, and crochet, meaning hook, combining the soft loop side and the catching hook side in one word. Why is the generic name hook and loop used?Velcro is a registered trademark, so generic implementations often use the name hook and loop, though in common usage velcro is also used generically for the same kind of fastener. More to ExploreMore from Apparel Search: Miscellaneous Definitions | Clothing Industry Glossary | Fashion Terms | Apparel Search Home
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