Patent 11324290 was granted and assigned to YKK on May, 2022 by the United States Patent and Trademark Office.
An element includes a head having an engaging convex portion protruding from one surface thereof and an engaging concave portion formed on the back of the engaging convex portion on the other surface; and a pair of leg portions extending from the head. A protrusion is formed on a side of the engaging concave portion close to the leg portions to protrude inward of the engaging concave portion.