Composite Hoop Lock Structure Against Sawing and Grinding

The patent applies composite materials by filling the hollow cavity of the metal tube with granulate material (such as concrete, ceramic, or other hard particles). This creates a composite structure where the metal tube provides tensile strength and structural integrity, while the granulate filling provides resistance to sawing, grinding, and cutting attacks. The composite design achieves enhanced security properties without requiring the hoop to be solid metal throughout, thus reducing manufacturing complexity compared to a fully solid construction.

The patent applies local quality by creating a differentiated structure where the locking structure is closed off from the cavity at critical locations. Specifically, the locking structure includes a closed end that seals against the cavity, preventing attackers from accessing the granulate filling through the locking mechanism. This localized closure at the locking structure provides enhanced security without requiring the entire tube to be solid or complex manufacturing processes. The open portions of the locking structure can still be easily manufactured, while the closed end provides the necessary security barrier.