How LEGO Bricks Connect and Stay Together

This patent describes the design of a toy building brick that uses studs on top and hollow tubes inside to create a strong, interlocking connection with other bricks.

What it covers

Based on the patent title "Toy building brick" and its historical context, this patent describes a building block with studs on its upper surface and hollow tubes on its lower surface. These tubes are designed to fit snugly around the studs of another brick. This creates a friction fit, allowing the bricks to interlock securely in various configurations. For example, two bricks can be stacked, and the tubes of the top brick will grip the studs of the bottom brick, holding them together.

What it doesn't cover

• —Does not cover toy building bricks that connect using magnetic forces.
• —Does not cover toy building bricks that use adhesive or glue for connection.
• —Does not cover toy building bricks that rely on clips or latches for interlocking.
• —Does not cover toy building bricks that lack the internal hollow tubes for friction fit with studs.
• —Does not cover toy building bricks with connection mechanisms that do not involve studs.

The clever bit

The clever bit was the inclusion of hollow tubes inside the brick, which, when combined with the external studs, created a precise friction fit. This design allowed bricks to interlock securely and also permitted offset connections, offering greater building flexibility than earlier, simpler stacking blocks.

Why it matters

This patent is historically significant as it describes the core interlocking mechanism of the classic LEGO brick. This design allowed for strong, versatile connections between bricks, enabling children to build complex and stable structures. This invention became the foundation of the LEGO Group's global success, transforming a simple toy into a creative system used by millions worldwide.

Real-world examples

• 1.LEGO System of Play bricks
• 2.LEGO Duplo bricks
• 3.Compatible third-party building bricks