This is probably a newbie question, maybe even a dumb one: What stops the key in opening a lock when there is an other key inserted on the other side? Furthermore: how does the emergency function work?
I've read a fair share of lock literature and taken quite a few locks apart, but either I missed it somehow or this info not easy to come by. So thanks a lot for the help!:
With Euro cylinder locks both sides of the lock cylinder share the same cam which operates the mechanism to open the door...
When a key from one side engages the cam and is rotated away from the key pull position the opposite cylinder can not engage the cam and with some Euros you can not even insert a normal key all the way into the cylinder...
The emergency function usually involves some manipulation of the lock from the outside to allow the exterior cylinder to function again...
Hey Evan, Thanks a lot for the help! Quite logical... Should have thought about that. So in case the lock is operable when both keys are fully inserted,then the cam has some sort of gearing allowing it funcsion as if it were split?