US Patent 10100575 Folding ladder with brace-locking apparatus

A brace locking mechanism locks the foldable braces of a folding ladder in the open position. The brace locking mechanism is used with a ladder that has a stepped unit and a support unit foldably attached to the stepped unit with a foldable brace extending between the stepped unit and the support unit. The brace locking mechanism comprises a lock block that is movable between a locked position in which the lock block prevents the foldable braces from moving out of their open position when the ladder is open, and an unlocked position in which the ladder may be folded into the storage position.