James wroteHow does the anti-pressure device work and what does it do?
Also why is there different height ‘bolt throwers’ ? on the key and in 3 pieces as well? mine didn’t come with a key.
I’ll answer your second question 1st, the three piece is purely decorative (ie the 3 bands of turning) The bolt thrower being angled is probably just to enable ease of entry into the keyway.
The anti - pressure is designed to prevent picking, as if you are intending to pick a lock you apply rotational tension first and then move the sliders second (the exact opposite of the key). However with this design the black steel element within the lock case is the locking point and it can move slightly and cause the brass ‘ anchor ’ to engage in the two cuts in the side of the inner cylinder. So the second rotational tension is applied - if the sliders have not been aligned to their gates first the anti - pressure device will trip and prevent the lock opening.
A.C.Hobbs tried and failed to pick a top of the range cotterill bank lock.
