Every lock is provided with an external casing which provides it an elegant look. After removing the external casing, one can observe the internal casing which press-confines the internal parts. After removing the internal casing too, one can observe the internal structure of the lock as shown in fig.

* A u-shaped spring loaded hook with a half cut slot at one end.
* A locking or stoping plate which engages with the slot in the hook to   "lock" the lock.
* SEVEN LEVERS:-

• Main lever (lever 1) provided with a projecting pin (stop) and slots at both the sides.


• Lever 2 (spring loaded, notched)
• Lever 3 (spring loaded, notched)
• Lever 4 (non spring loaded, unnotched)
• Lever 5 (non spring loaded, unnotched)
• Lever 6 (spring loaded, notched)
• Lever 7 (spring loaded, notched)

NOTE:-

• Generally levers ( lever 2 to 7 ) have a slot inside them.
• Spring loaded levers are notched on the inside of the slot.
• Non spring loaded levers do not have any notch.
• The undersides of each lever may be uniquely shaped and ordering of levers in different locks is different to make them unique.
• Key is provided with cuts and projections corresponding to the variously shaped undersides of different levers.
• The motion of the engaging plate is controlled by the main lever.

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