Abstract: A previously used lock assembly constructed for operation using a given key may be operated by a different key after rebroaching. Instead of requiring an expensive, complete replacement of a lock assembly and its operable keys, the present invention allows a lock assembly to be refitted for a different key by a relatively inexpensive replacement of its plug and at least one of the tumbler components, preferably the bottom pin only, of one or more preexisting sets of tumbler components, as needed to modify the lock to receive the different key.

Abstract: A card type locking apparatus having a chamber enclosed by an upper half and a lower half and having a slidable element, a spring, and four spring plungers in the chamber. When a card plate with raised blocks acting as security codes thereon is inserted into a preset opening provided on the locking apparatus, the raised blocks lift the spring plungers and urge the pin rods mounted on the spring plungers to align horizontally. When the card plate is pressed further the four pin rods enter a window formed on the upper half, which results in the backward movement of the slidable element and the release of the hook, producing the unlocked state.