Lock monitor

Claim 1

A lock monitor for fitting to lockable objects that have locks that incorporate a bolt mechanism including a slidable bolt having an engaging face at the free end thereof and a mortise, where the opening of said mortise is larger in at least one dimension than said engaging face of said slidable bolt, said lock monitor comprising: an electrically operated status indicator; an actuating arm attachable to the engaging face of said slidable bolt, where said actuating arm extends generally perpendicular to the direction of movement of said slidable bolt; a contact plate attachable to said bolt mechanism adjacent to said engaging face of said slidable bolt; and first and second circuit contacts located on said contact plate, said first and second circuit contacts being connected in a circuit monitored by said status indicator, with said first and second circuit contacts being separated and insulated from each other such that said circuit remains open until the separation between said first and second circuit contacts is bridged by engagement with said actuating arm when said slidable bolt is disengaged from said mortise, said engagement between said actuating arm and said first and second circuit contacts causing said status indicator to register a change in status of said lock.