A ruler in flexible form is called a measuring tape or tape measure. It consists of fibre glass, a ribbon of cloth, or plastic. It also has a metal strip with metric units and sometimes imperial units are added to the linear-measurement markings. It can easily be carried due to its flexibility, which is appropriate for a great length and can be used in measuring corners or curves. Tape measures with lengths of about 100 metre or 300+ ft are used by surveyors.
Measuring tapes that are made out of fibre glass are used in sewing, while those made of plastic or flexible cloth are purposely made for use in dressmaking and tailoring. Tape measures that are made of a curved, stiff metallic ribbon are used in construction or carpentry. This kind of tape measure can remain straight and stiff when stretched, but draws back into a convenient storage coil.
On July 14, 1868, a resident of Connecticut named Alvin J. Fellows patented the design of the modern spring measuring tapes. The tape measure designed by Fellows was said to be an improvement on the previously designed tape measures as per text of his patent. After Fellows’ patent, the spring measuring tape existed. This spring measuring tape slowly started to replace the common carpenter’s folding wooden ruler; Fellows’ tape acquired wide usage in the early 1940s. In the United States, some tape measures with additional marks, called ‘black truss’ markings, used to mark off equal length of trusses in roofing materials.