Dunc came across one of these latches being fitted to a door in the workshop this morning. His curiosity got the better of him, so he paused to take a closer look. He assures me that what I thought to be quite a common piece of door hardwear is, in fact, quite rare on steel doors.
Most of us are familiar with this sort of latch and it is fairly obvious how they work. The main ‘live’ bolt is spring loaded and has a rounded edge. For the door to open the bolt has to be withdrawn into the casing. When the bolt is released, the door can be closed by simply pushing the door into the frame. With the deadlock set, the bolt locks and cannot be pushed back from the outside with a piece of plastic when the door is closed.
On most doors, these sorts of latches are not known to be particularly secure, but when fitted to steel doors the retainer is anchored by use of a custom made steel plate which offers greater protection from casual attack.