Abstract: Disclosed is a lock having a lock tongue with a rearwardly facing elongated rack having teeth and a plurality of notches disposed at intervals along it and a rocking arm having a camming surface and a lug which is sized to be received by the notches in the rack. A rotationally mounted sector gear is provided which has teeth arranged to engage with the teeth of the rack and a cam arranged to engage the camming surface of the rocking arm. The sector gear in one rotational position drives the lock tongue and in another rotational position locks the lock tongue in place by means of the cam and camming surface causing the lug to engage one of the notches.