by Hanno van der Bijl
Like a lot of other automated machines today, we take the automatic opening and closing of elevator doors for granted. When the elevator was first invented in the mid-19th century, the elevator operator or the passengers themselves had to manually close the doors. The door to the elevator shaft also had to be closed manually. You have probably seen movies where well-groomed elevator operators open and close sliding doors for wealthy patrons. But life in tall buildings was not always that idyllic. Elevator and shaft doors were left open. Unsuspecting passengers would step into the shaft and fall down a number of stories, sometimes to their death.
One of the men who made a significant contribution to the automation of elevator doors and the safety of buildings was Alexander Miles, an African-American inventor. On October 11, 1887, he was awarded U.S. Patent 371,207 for an improved mechanism for opening and closing the doors to the shaft and the elevator:
“To whom it may concern. –
Be it known that I, ALEXANDER MILES, a citizen of the United States, residing at Duluth, in the county of St. Louis and State of Minnesota, have invented certain new and useful Improvements in Elevators, of which the following is a specification.”
Miles’ patent describes how the elevator cabin doors open and close through a series of levers and rollers. When the elevator came to stop at a floor, a flexible belt attached to the cabin, with its ends running over drums at the top and bottom of the shaft, would open the shaft doors. He describes the goals of his invention as:
“First, to provide mechanisms operating automatically to close the shaft openings above and below the elevator-cage, and so preclude the possibility of danger by reason of such openings being left unclosed through negligence; and, second, devices operating automatically by the movement of the cage to open and close the cage-doors when set by an operator to be in engagement at any desired floor.”
From Miles’ patent: “Fig. 3 is a detached view of one of the cage-doors and its operating devices. Fig. 4 is a detail of the devices for sliding the roller-wheels carried by the levers to and from positions to be engaged in the grooves. Fig. 5 is a cross-section of one of the uprights of the shaft, showing the beltway and a portion of one of the belt cross-strips in it. Fig. 7 is a top view of the sliding doors and their tracks.”
Miles was born in Ohio on May 18, 1838. After working in Waukesha, Wisconsin as a barber, he moved to Duluth, Minnesota where he met his wife, Mrs. Candance J. (Shedd) Dunlap, a widow with two children. In 1876, their daughter, Grace, was born. Eleven years later, when he was 49 years old, he was awarded the patent for his elevator invention. Two years later in 1889, he moved his family to Chicago where he worked as a laborer according to the city directories. By the next year, the directories listed him as an insurance agent. In 1903, he moved his family to Seattle where he worked in a hotel as a barber. He passed away on May 7, 1918.
Miles was recognized for his work when he was inducted into the National Inventors Hall of Fame in 2007. The value of his work is evident today every time an elevator’s doors open and you step into or out of the cabin. The automatic opening and closing doors creates a sense of mystery for elevator passengers. His invention has contributed to the creation of this aura as well as the convenience and safety of people movers in tall buildings.
From Miles’ patent: “Fig. 6 is a perspective view of an elevator shaft and cage provided with the improvements, but having a single cage-door.”