écrou

An "écrou" is a mechanical component commonly used in fastening applications, primarily to secure bolts and threaded rods. Originating from French terminology, the term "écrou" translates to "nut" in English. It is a cylindrical or hexagonal piece with internal threading, designed to engage with a complementary threaded shaft or bolt.

The primary function of an écrou is to create a secure attachment between two or more components, preventing undesired movement or loosening due to vibration or load. The most common shape for an écrou is hexagonal, facilitating easy tightening and loosening with standard tools such as wrenches or spanners. Variations include lock nuts, wing nuts, and cap nuts, each designed for specific forces or accessibility constraints.

Ecrous are manufactured from diverse materials, including steel, stainless steel, brass, nylon, and other alloys, depending on the application requirements such as strength, corrosion resistance, or electrical insulation. They are often used in conjunction with bolts, screws, or threaded rods in machinery, construction, automotive, aerospace, and electronics industries.

Standardization of écrous is maintained through organizations like the International Organization for Standardization (ISO) and the American National Standards Institute (ANSI), which specify dimensions, materials, and performance criteria. Common sizes range from small metric diameters (e.g., M3, M6) to large industrial sizes.

In summary, the écrou is a fundamental fastener component that plays a vital role in assembly and maintenance across numerous fields, offering a simple yet effective means of securing connections in various mechanical systems.