Velcro — The Hook-and-Loop Fastener Inspired by a Burr

This patent describes a two-part fabric fastener system. One side is covered with tiny rigid hooks — stiff loops cut in half so they form a 'J' shape. The other side is covered with soft, uncut loops. When pressed together, the hooks catch on the loops and the two surfaces bind. When pulled apart with sufficient force — especially from one edge, like peeling — the hooks release the loops and the surfaces separate cleanly. The cleverness is in the geometry: hooks release when peeled (angled pull) but resist when pulled straight apart (shear load). The original material was nylon, chosen for its resistance to repeated flexing.

The clever bit

De Mestral was a Swiss engineer who returned from a hunting trip in 1941 with cockleburs stuck all over his wool pants and his dog's fur. Instead of being annoyed and moving on, he put the burrs under a microscope and noticed that each seed was covered with tiny curved hooks that caught on the loops in fabric and fur. He spent eight years trying to replicate this in manufactured form — the challenge was making loops soft enough to catch but hooks rigid enough to hold and release cleanly, and making them survive repeated use. The name 'Velcro' comes from the French words 'velours' (velvet) and 'crochet' (hook). NASA's use of Velcro in the Apollo program — to keep objects from floating around in zero gravity — made it globally famous.

What it does not cover

• ×Magnetic closures or snap fasteners — different fastening mechanisms
• ×Adhesive-backed variants — the patent covers the fabric structure, not how the material is attached to surfaces
• ×Micro-scale Velcro (gecko-inspired dry adhesives) — materials science descendants that operate at nanoscale
• ×Specific applications (shoes, clothing, medical devices) — the patent covers the fastener structure, not its uses