Chubb Safe Deposit
The setup
in this lock is :- Bank guardian key operating a spring loaded
shutter over the renters keyway who also can set up 4 combination
dials. The removable dial has 20 numbers. When the renters key
is turned anti clockwise to close the lock the action automatically
scrambles the combination.
The combination is adjustable and the lock dates from 1920 -25
period.