I've inherited a 4 drawer metal filing cabinet which can be locked but not unlocked. It has the standard locking bar arrangement on the right which prevents more than one drawer being opened at a time and doubles as the cabinet lock via a key.
Taking a drawer out gives access to the locking bar but the mechanism is pretty well hidden. The bar appears to have some kind of over-centre catch which soft latches it in the up or down position as the drawers open and close, really straightforward stuff.
The key operated part is a simple cam lock with a roller at the end to lift the bar when locking but there is nothing to push the bar back down when unlocking, the roller returns down an open slot.
My thoughts are that the bar should drop by gravity and that soft latching in the up position is a fault caused by a dirty mech or a broken spring.
Any thoughts or does anyone fancy having a look at their own cabs to see if the bar drops by gravity?
It's a Vickers if that helps.