Lock for sliding closure

Locking apparatus for a sliding closure slidable within a frame defining a closure plane, the locking apparatus comprising:

• a deadlock including:
• at least one locking tang movable transversely to the closure plane, between:
• a locking position where the at least one locking tang extends laterally, in a direction transverse to the closure plane, beyond the closure to be received within a corresponding locking recess in the frame, such that the at least one locking tang resists opening of the closure;
• and
• a release position where the at least one locking tang is withdrawn within the dimensions of the frame, such that the closure may be opened or closed wherein the at least one locking tang is biased to the release position;
• and
• an actuating tang which is extendible longitudinally from the closure, to move the at least one locking tang into its locking position,
• wherein the at least one locking tang comprises a cam surface whereby extension of the actuating tang pushes on the cam surface of the respective at least one locking tang and causes the actuating tang to matingly engage with the cam surface of the at least one locking tang to move the at least one locking tang laterally, and
• wherein the actuating tang is movable by one or more of:
• operation of a key or a turn snib, and spring force;
• and
• a mortice lock including:
• at least one mortice locking tang movable transversely to the closure plane, between:
• a locking position where the at least one mortice locking tang extends laterally, in a direction transverse to the closure plane, beyond the closure to be received within a corresponding locking recess in the frame, such that the at least one mortice locking tang resists opening of the closure;
• and
• a release position where the at least one mortice locking tang is withdrawn within the dimensions of the frame, such that the closure may be opened or closed wherein the at least one locking tang is biased to the release position;
• and
• a mortice actuating tang which is extendible longitudinally from the closure, to move the at least one mortice locking tang into its locking position,
• wherein the at least one mortice locking tang comprises a cam surface whereby extension of the mortice actuating tang pushes on the cam surface of the respective at least one mortice locking tang and causes the mortice actuating tang to matingly engage with the cam surface of the at least one mortice locking tang to move the at least one mortice locking tang laterally, and
• wherein the mortice actuating tang is biased outwardly from the closure to an extended position, to thereby bias the at least one mortice locking tang to the locking position, and
• wherein the at least one mortice locking tang comprises an external cam surface, such that when the closure is slid to a closed position, the external cam surface engages with the frame to push the at least one mortice locking tang to its release position, until it reaches the recess within the frame and is biased back to the locking position.