What Exactly Is a Rim Lock?

Rim Locks are often recommended as the safest of door-locking options for residential properties.

Rim Lock Basics

Rim lock doors are also called internal locks, since they are found on the internal side of the door. Being slightly old fashioned in their working and appearance, they are sometimes not preferred for securing the main entrance doors. Some rim locks are referred to as rim deadbolt locks. These locks are more likely to be found on the back doors of older houses, since rim locks were very common a few decades ago.

Understand Working of Rim Lock

The working mechanism of a typical rim lock is easy-to-understand. When the lock is engaged, a bolt is extended from the side of the door. This bolt is pushed into a dedicated notch on the frame of the door. Thus, the door cannot be opened. For retracting the bolt to open the door, a key is needed. Most of the rim locks have a cylinder lock mechanism, wherein the key is inserted into the lock and the door is disengaged. When the key is inserted and moved, it turns a cylinder which in turn is connected to a cam. The cam in turn moves a plug, which helps to slide the bolt either forward or backward.

The cylinder lock is considered a bit old fashioned, as compared to the usual spring-based locking mechanism, wherein the lock is smoothly released. In comparison, rim locks use heavy bolts and are slightly harder-to-handle. The dependence of rim locks on a key for disengaging the locks makes them the favored choice among some home security experts.

Some rim deadbolt locks are offered with double-cylinder locks. These have key slots on both the sides. The more common variety of rim lock deadbolts has key slot on 1 side only--called the entry-only type rim lock.