Velcro On Steroids

Researchers design steel analog of well-known fastener.

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By Janet Raloff, Science News

Hook-and-loop tape is the generic name. But everyone knows the plastic fastener that can be reused and repositioned endlessly as Velcro. Now, German engineers have developed industrial-grade analogs for automotive and other applications. Made from steel, the newly patented fasteners can operate at temperatures as high as 800° Celsius and at tensile loads of up to 35 metric tons per square meter.

Industrial companies approached the Technical University of Munich’s Institute of Metal Forming and Casting four years ago about developing the new connectors. They’re patterned on the burrs that some plants have evolved to adhere to the coats of animals for seed dispersal.

In the new Metaklett fasteners, rows of protruding, gently barbed points cover one surface of a perforated metal strap. A second strap houses rows of catches that stand poised to lock any barbed points in place. Pulling the paired straps apart releases the barbs. But just as with Velcro, the locked straps won’t loosen and slide with strong shear forces.

Josef Mair, a mechanical engineer who heads a team that helped develop the university’s working prototypes, says the connectors could be used in automotive systems — such as near exhaust pipes where extreme heat and corrosive gases might degrade other fasteners. The strips could also be used to snap aluminum siding onto homes or for attaching curtains in hospitals where fasteners are regularly sterilized with strong chemicals.