NCJ Number
84094
Journal
Security Management Volume: 26 Issue: 7 Dated: (July 1982) Pages: 10-11,17-18
Date Published
1982
Length
4 pages
Annotation
Types of locks, identified by how they are installed and how they operate, are described, and their advantages and disadvantages for security are explained.
Abstract
Although all types of locks can be defeated given sufficient time, locks require an intruder to expend extended entry time and provide evidence of forced entry, which increase the chance of apprehension. Four types of lock installations are commonly used on doors: mortise locks, bored (bore-in, cylindrical, key-in-the-door, or tubular) 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. While generally an excellent lock for commercial applications, mortise locks are less effective in doors that might be weakened by the cutout cavity. A bored lock is installed by drilling a hole through the door to accommodate the cylinder, which is housed in the door knob, and through the front edge of the door to the cylinder for the bolt assembly. While this is a popular model because of its quick installation, it can be easily defeated. Unit locks are installed by making a U-shaped cutout in the front edge of the door and slipping this self-contained unit into the cutout. This unit provides excellent security. Rim locks are mounted on the surface of the door to supplement another primary lock. Locks are also typed by whether they use traditional keys or operate without keys. The keyed locks in use are warded locks, level locks, and cylinder locks. Locks which operate with pushbutton combinations or cards eliminate the risks posed by the use of keys but have the disadvantages of being either time consuming to open or subject to computer or power failure.