The tape measure has become a staple in household tool chests. While longtime users are typically familiar with the parts of a tape measure, new users might not be aware of some of the functioning parts, such as the locking mechanism. Although there are not many parts of a tape measure, each has a function that serves the overall design.
A tape measure consists of a metallic tape with length markings on it, which can be in inches or centimetres or both. The housing of the tape measure holds the coiled tape. At the end of the tape is a tang, or lip, which is used to catch onto the edge of an object being measured. The housing is typically divided into halves. There is a spring coil, which provides the retraction force on the tape. Another tape measure part is the button, which is connected to a U-shaped tongue that can press down on the tape within the housing. A locking mechanism locks the U-shaped tongue onto the tape, and a release catch releases the locking mechanism.
Some tape measures have digital readout displays. The length on the display is an indication of how far the tape has been pulled out of the housing and is a measurement to the tang at the end of the tape. Tape measures typically come in several standard lengths, which include 25, 50 and 100 feet. Some housings are made of plastic, while other types of tape measures have metal housings.
Many tape measures also include a clip on the side of the housing. These clips can be handy because the tape measure can be clipped onto a belt or trousers pocket. When working around the house, having a tape measure nearby can be handy when needing a quick measurement. Digital tape measures are powered by batteries, and although they can last a long time, much like watch batteries, they will eventually have to be replaced.
Tape measures came from work with tailoring, and the original tape measures were strips of cloth with length markings on them. The modern spring-loaded tape measure evolved from a device patented in 1868.
For some tape measures, there is a display window on top of the housing. The tape can be seen through this window. The window has a line that indicates the length marking on the tape that should be read. This line in the window indicates the length from the tang at the end of the tape to the other end of the housing. This is so that the housing can be part of the measurement. This comes in handy for floor measurements, when the tang is placed against the wall at one end of the room and the tape measure is simply snuggled up to the other wall. You can look down at the window and read the length.