- $29 for $100 worth of storage rental and move-in fees
Combination Locks: Safety in Numbers
You’ll want to use a combination lock to keep your stuff secure. Learn just what’s protecting it with Groupon’s look at the combination lock’s inner workings.
Although they’ve made skeleton keys obsolete for everyone but medieval dungeon masters, combination locks do have a key—it’s just hidden inside. In that sense, turning a padlock’s dials is like drilling a keyhole, thanks to a surprisingly simple mechanism. Inside the hull, an axle supports a set of tiny wheels equal to the number of inputs in the combination (usually three). Each wheel has two distinct features that contribute to the combination: a deep notch somewhere along its edge, and a small peg jutting from its face.
Engaging each of these pegs in the correct order is the goal of the fussy routine of precise turns that makes every seventh grader late to class. The first two carefree clockwise spins of the dial let each peg catch on its neighboring wheel, causing all the wheels to turn as one. Then, the puzzle begins, and it’s time to start lining up those notches. Most dials have you spin clockwise until you reach the first number, at which point the first notch is in position. Changing to counterclockwise then leaves that first wheel where it is so only the remaining wheels turn. Upon reaching the second number, the second notch aligns with the first, and so forth until all the wheels are in line.
At this point, the keyhole comes into play. At the end of that U-shaped metal shackle is the latch assembly, typically a semicircular piece of metal trapped by a simple lever called a pawl. When locked, the pawl presses against the stack of cams and can’t budge. But when all the notches line up, they form a convenient slot for the pawl to slide into, triggering the latch and freeing the shackle.
Theoretically, you could stack up as many wheels as you’d like to create a lock with an extra-long code. But even a typical lock with 40 numbers on its face and a three-digit code has tens of thousands of possible permutations. Most manufacturers also mark the wheels with shallower “false” notches to thwart any lock-pickers who try to puzzle out the code by spinning the dial and feeling for motion. There’s no reason that code has to be made of numbers, either. Master Lock patented a model that works with directional gestures, and the first known design, described in 1206 in inventor al-Jazari’s Book of Knowledge of Ingenious Mechanical Devices, was based on 12 letters of the Arabic alphabet.
Most Popular Service: self storage
Staff Size: 50+ people
Average Duration of Services: 30 Minutes or Less
Brands Used: StorageMart
Pro Tip: Bring your photo ID along. Ask us for tips on moving, packing and storing.
Q&A with the VP or Marketing
Describe a time your services really changed a client's life for the better.
We have a lot of customers who felt overwhelmed in their homes by the lack of space. We help them by being their "other place" where they can store the things they don't need right now. We have had many people tell us how much more livable their homes are now that they are better organized, less cluttered and more open.
Do you or your staff have any special certifications or degrees?
Our staff is well versed in best practices for moving and packing and storing.
When and how did you first develop a passion for your work?
We get a good feeling knowing people don't have to worry about what to do with their extra belongings during a move or a renovation project.
Is there anything else you want to add that we didn't cover?
We have customers from every walk of life and every demographic. Everyone needs storage and we are here to help.