How Does a Safe Combination Lock Work?
Certain safes utilize combination locks to safeguard the material inside. In a combination lock, only a specific series of numbers will get the lock to open and allow entry. Unlike a keypad or other electronic device, a combination lock does not require electricity to run and instead utilizes a very basic, yet effective, system to work.
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Combination Dial
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On the outside of the safe is a combination dial. This is what the safe opener turns to input the numbers in the combination. The amount of numbers in the combination depends entirely on the specific safe that is being opened. The dial is attached to a spindle that runs through several wheel notches and connected on the other side to the drive cam, which has a metal tooth jutting out from it. By using the tooth, the drive cam can turn the wheel notches, which also have metal teeth of their own, in a specific direction, lining up their holes with the fence, a metal bar that sits on top of the lock. Once the notches have their holes lined up, the fence can fall due to gravity and the lock will open.
First Turn
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In an example, the code is going to be right 42, left 32, right 12. This means the combination will have to be entered by first turning the dial to the number 42, turning left to the number 32, and turning right to the number 12. In the first turn (right 42), the user turns the dial connected to the drive cam. The drive cam uses its metal tooth to move the front wheel notch. When the user gets to 42, the front wheel notch aligns its opening with the fence. The front wheel notch is in place, meaning one-third of the combination is intact.
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Second Turn
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The user now enters the second number of the combination (left 32). This means, the user turns the dial left to the number 32. Due to entering the first number correctly, the user now has control of the second wheel notch. By turning the dial to the number 32, the connected drive cam at the end of the lock uses its metal tooth to line up the second wheel notch. If entered correctly, the hole in the second wheel notch is then aligned with the fence.
Third Turn
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The user now must enter the final number in the combination (right 12). By turning the dial to the right and to number 12, the dial cam uses its metal tooth to move the third and final wheel notch in a direction that will line up its opening with the fence.
Open Lock
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As soon as all three wheel notches in the lock are lined up, the fence will fall into the three lined up openings. The fence opens the bolt in the back of the lock, opening the safe and allowing the person access to whatever is inside.
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References
- Photo Credit Safe box image by Raulmahón from Fotolia.com
