The Elevator Brake
The elevator brake was invented by Elisha Otis. At first he started making safety brakes for trains that could make the trains stop faster. This business hadn't lasted very long because the power supply was cut off. He moved and started a bedstead factory. The elevator brake was invented because Elisha couldn't get the debris from the lower floor to the upper floors in the factory easily. He had designed and tested his own safety elevator with his sons and it worked but he never thought that to patent or sell the safety elevator. Eventually he did a demonstration with the safety elevator and everyone was amazed and sales started doubling every year.