ABSTRACT
The year was 1854. At the Crystal Palace Exposition in New York a curious crowd had gathered around a stunt that was in progress. A man stood on a wooden platform that was suspended by a rope high above the ground. (See Figure 1.1.) Two vertical guard rails flanked the platform on either side. As the crowd watched, an axe-man severed the rope sending the platform into what seemed certain to be a free fall. However, instead of going into a free fall, to the crowd’s surprise, the platform fell only a few inches before a braking apparatus, attached to the platform, latched into the vertical guard rails arresting the platform’s fall. In this staged stunt, the man on the platform, Elisha Graves Otis, demonstrated that his invention, the braking apparatus for elevators, could ensure the safety of the passengers even if the elevator cable were to snap [Srinivasan 2005].
