chocks

Chocks are wedge-shaped blocks used to prevent unwanted movement of wheeled equipment by blocking the wheels’ contact with the supporting surface. They are commonly employed to secure parked vehicles, aircraft on the ground, ships at berth, and heavy machinery during maintenance. By pressing against the wheel, chocks create friction and a stopping force that resists rolling. When used on slopes, chocks are placed on the downhill side of wheels and, where practical, on additional wheels to reduce the risk of movement.

Chocks come in a range of materials and forms. Common types include wooden blocks, rubber or plastic blocks, and metal wedges. Some are molded with textured or serrated faces to enhance grip, and many are brightly colored or have reflective strips for high visibility. Portable chocks often include handles or integral anchors, and some specialized chocks are designed for aircraft, which may feature lanyards or locking mechanisms to prevent loss.

Use and installation guidelines emphasize suitability and fit. Select chocks sized for the wheel diameter and width, and ensure they are placed on firm, level ground. Position chocks securely against the wheel to prevent rotation, and use multiple chocks for multi-wheel configurations when possible. Do not rely on chocks as the sole means of restraint in unstable conditions; engage parking brakes where provided and follow applicable safety procedures. Regularly inspect chocks for cracks, wear, or damage and replace as needed. Proper storage keeps chocks dry and free from contamination to maintain effectiveness.