The spring tape measure has existed in the U.S. since Bang's patent in 1864, but its usage did not become very popular due to the difficulty in communication from one town to another and the expense of the tape measure. In the late 1920s, carpenters began slowly adopting H. A. Farrand's design is the one more commonly used. Farrand's new design was a concave/convex tape made of metal which would stand straight out a distance of four to six feet. This design is the basis for most modern pocket tape measures used today.

Source: Wikipedia