A foldable cart comprising an upper frame, a lower frame, and a plurality of legs attached to and supporting the upper frame and the lower frame is disclosed. Each leg is configured to be folded into a folded configuration from an erect configuration. Each leg comprises a lock configured to hold the leg in the erect configuration. The lock comprises a lock bar movable between a locking position and an unlocking position, an internal support brace, wherein the lock bar extends through the internal support brace, and a spring configured to bias the lock bar into the locking position to hold the leg in the erect configuration. The lock bar is spring-loaded against the internal support brace, wherein the entire length of the spring surrounds the lock bar, and wherein the spring is confined entirely within the internal support brace.