US Patent 9435138 Modular lock plug

A plug assembly including, a plug, a sidebar movably mounted on the plug, and a plurality of rack pins seated in the plug. The sidebar is biased to an outer position in which the sidebar extends beyond an outer surface of the plug. Each rack pin is a single-piece unitary structure including a key-following leg, and a sidebar-engaging leg. The sidebar-engaging leg includes at least one true gate and a plurality of false gates. When a true gate of each rack pin is aligned with the sidebar, the sidebar is free to move radially inward to an inner position.