Information AboutVelcro |
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HISTORY The hook and loop fastener was invented in 1948 by Georges De Mestral , a Swiss Engineer . The idea came to him after he took a close look at the Burdock seeds which kept sticking to his clothes and his dog's fur on their daily walk in the Alps . De Mestral named his invention "VELCRO" after the French words ''velours'', meaning 'velvet', and ''crochet'', meaning 'hook'. COMPOSITION Hook and hooks, and a "loop" side, which is covered with even smaller and "hairier" plastic loops. There are many variations to this which include hooks on both sides, for example. When the two sides are pressed together, the hooks catch in the loops and hold the pieces together. When the layers are separated, the strips makes a characteristic ripping sound. The term ''VELCRO'' is a registered Trademark in most countries. Generic terminology for these fasteners includes "hook and loop", "burr" and "touch" fasteners. USE The strength of the hook and loop bond depends on how well the hooks are embedded in the loops 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. 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 fastener surface the force is spread evenly as with rigid pieces. Two ways to maximise the strength of a bond with one or more flexible pieces are:
APPLICATIONS Because it is easy to use, maintenance free, and totally 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 velcro over laces. A stronger version of the hook-and-loop material have even made it possible to create semi-permanent bonds (where it is extremely hard to separate the hooks from the loops), useful for higher stress applications (see section above). The strength of a hook and loop bond depends on how much surface area is in contact with the hooks: full-body hook and loop suits have been made that can hold a person to a suitably-covered wall. Research is being performed on developing "silent velcro" for military clothing and other covert uses. ADVANTAGES AND DISADVANTAGES Advantages:
Disadvantages:
VELCRO IN FILM AND TELEVISION
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