Double Bit Locks?
The Double Bit locks are built and operate much differently than the conventional and more popular pin locks. Their biggest disadvantage is that they do not allow for as many master-key combinations as pin tumbler locks.
In a basic, fixed, lever lock design, the entire lock is enclosed in a case – The simple lever lock has three or more lever wafers or plates that pivot on a post and are pushed into the ‘locking’ position by springs, which are bound against the case and attached to the tail end of each lever plate. When the original key is inserted into the lock and turned, it raises each plate (wafer) to the point where the fence of the lock’s bolt can clear the obstruction or face of each wafer, which also blocks each tumbler’s gate. When all the levers are in this position, the fence can be thrown through each tumbler’s gate, which pushes the bolt into the retracted position.
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