Tubular pin tumbler lock

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A tubular lock and key

A tubular pin tumbler lock, also known as an ace lock, circle pin tumbler lock, or radial lock, is a variety of pin tumbler lock in which six to eight pins are arranged in a circular pattern, and the corresponding key is tubular or cylindrical in shape.

Design[edit]

The design of a tubular lock is similar to the pin tumbler lock, in that there are several stacks of pins. The key is a cylinder shape with notches cut around the outer edge. Each of these notches depresses a single pin inside the lock to a specific height allowing the lock cylinder to turn freely.

Mechanism
The key pins (red) and driver pins (blue) are pushed towards the front of the lock, preventing the plug (yellow) from rotating. The tubular key has several half-cylinder indentations which align with the pins.
The protrusion on top of the key fits into the rectangular recess in the lock, causing the indentations to properly align with the pins. When the key is inserted, the gaps between the key pins (red) and driver pins (blue) align with the shear plane separating the plug (yellow) from the outer casing (green).
With the pins correctly aligned, the lock may turn.

Uses[edit]

Tubular locks are commonly seen on bicycle locks (such as the Kryptonite lock), Kensington computer locks, elevators, and a variety of coin-operated devices such as vending machines, and coin-operated washing machines.

Tubular pin tumbler locks are generally considered by the general public to be safer and more resistant to picking than standard locks. This is primarily because they are often seen on coin boxes for vending machines and coin-operated machines, such as used in a laundromat. However, the primary reason the locks are used in these applications is their lack of the depth requirement that most other locks require.[1]

Vulnerabilities[edit]

Such locks can be picked by a special tubular lock pick with a minimum of effort in very little time; it is also possible to defeat them by drilling with a hole-saw drill bit. Standard tubular-lock drill bit diameters are 0.375 in (9.5 mm) and 0.394 in (10.0 mm).[2] To prevent drilling, many tubular locks have a middle pin made from hardened steel or contain a ball bearing in the middle pin.

Tubular locks, used on kryptonite bike locks, can be opened with the back end of a ball point pen,[3][4] because they only used two pins.

See also[edit]

References[edit]

  1. ^ "A Beginner’s Guide to Tubular Lock Picking". 
  2. ^ "Tubular Lock Saws". hpcworld. HPC. Archived from the original on 28 September 2011. 
  3. ^ "Twist a Pen, Open a Lock". WIRED. Retrieved 2016-03-15. 
  4. ^ Polgreen, Lydia (2004-09-17). "The Pen Is Mightier Than the Lock". The New York Times. ISSN 0362-4331. Retrieved 2016-03-15.