NCJ Number
101025
Date Published
1986
Length
14 pages
Annotation
Locks are distinguished by how they are installed and how they work (key and keyless), and each type has advantages and disadvantages.
Abstract
The common types of door lock installations are mortise locks, bored locks, unit locks, and rim locks. A mortise lock, including a latch and a deadbolt, is rectangular and fits into a large cavity cut into the door. This cut may weaken some doors. A bored lock is installed by drilling a hole through the door for the cylinder, which is housed in the door knob, and through the front edge of the door to the cylinder for the bolt assembly. These locks are easily defeated by knocking off the door knob. Unit locks are installed by making a U-shaped cut in the front edge of the door and putting the self-contained unit in the cutout. These locks are easy to install and difficult to defeat. Rim locks are mounted on the door's surface to supplement a primary lock. Interlocking bolts and extra-long throw deadbolts are rim locks that provide maximum security. Among the keyed locks in current use are warded locks, which have an open keyway; lever locks, which are typically used on safe deposit boxes, strong boxes, and post office boxes; and cylindrical locks, which provide for the key to rotate the cylinder plug rather than the bolt. Cylindrical locks can be changed by inserting a new tumbler arrangement and cutting new keys to match it, giving such locks an advantage when keys are lost or stolen. Keyless locks consist of pushbutton locks, and card entry systems. When installed and used properly, these locks can be the mainstay of an access control system, but they can be defeated or malfunction under a number of conditions. Glossary and 7-item bibliography.