Whether you use an elevator at work, home, or travel, they are a marvel of engineering genius. Most people who ride on them don’t take the time to appreciate what it takes to make it work but quickly become frustrated when it doesn’t. Many people think they are a modern invention, but the first primitive elevator surfaced around 236 B.C. by Greek Mathematician Archimedes. His first elevator was comprised of hoisting ropes wrapped around a drum and rotated by manual force by people propelling a capstan. According to Wikipedia, “A capstan is a vertical-axled rotating machine developed for use on sailing ships to multiply the pulling force of seamen when hauling ropes and hawsers. The principle is similar to that of the windlass, which has a horizontal axle.”
Did you know that a multi-complex of rooms existed in Rome, including animal pens and tunnels all below the Colosseum? Many elevators were powered by hundreds of men using winches and counterweights to move gladiators and large animals through various shafts in the arena for battle.
By 1743 Louis XV developed the “flying chair,” designed to bring one lady to her quarters on the third floor of the Palace of Versailles. In his retreat, château de Choisy, a “flying table,” enabled the king and their guests to dine without interruption from the servants. When the bell rang, a table would ascend from the kitchen beneath the dining room to deliver a lavish meal with all the trimmings.
Once the 19th century hit, elevators were now powered by steam or water. Unfortunately, ropes wore out, and brakes were yet to be invented, which was unsuitable for passengers. In 1852 Elisha Graves Otis engineered a safety brake that changed the vertical transport industry. Should an elevator’s hoisting rope break, a spring engaged gears on the car, which they called pawls. Once this mechanism was activated, it pushed out to the sides of the elevator car sides to the rails on the side, thus forcing it to lock in and suspend the elevator car safely in place. In 1957 Otis Elevator installed its first commercial elevator in a five-story department store in New York City.
Otis now made it possible to build skyscraper buildings, making them the most valuable piece of real estate. Now that we know how they became a staple of many buildings today, let us look at the different application types of elevators available. Elevators are frequently used for either: passengers, service, freight, or dumbwaiter.
Elevators today come in one of four engineering flavors: Traction Elevators, Hydraulic Elevators, Machine-Room-Less (MRL) Elevators, and Vacuum (Air Driven). The most important thing when choosing an elevator is understanding the design process and that every part of the building works together as a safe, reliable machine. When I refer to ropes, they are made of solid metal and solid today.
There are two types of traction elevators: Geared and a Gearless Traction Elevator. Geared Elevators use a motor that turns a drive chain that rotates the sheave in a geared elevator. In a traction geared traction elevator, the motor, wheel sheave, and control system are above the elevator’s machine room. The critical thing to note is that the main wheel is driven by a gearbox directly attached to the motor in the geared elevators. Geared elevators are less expensive, nosier, and require more maintenance, and older technology/some ropes are responsible for lifting and have counterbalances on the other side of the sheave.
Gearless elevators are also traction based. However, the wheel will be attached directly to the motor, thus quickly rotating the drive sheave. Each time the sheave rotates, the elevator car ascends and descends accordingly. Gearless elevators are designed to operate at higher speeds, able to accommodate more increased floor travel, and support passengers and freight; the unique high motor torque operates at lower speeds and works with a “U” shaped recess which allows it to grip the rope and its motor interfaces directly with the drive pulley. Remember that in a gearless elevator, the wheel that operates it is placed above the elevator, referred to as MRL (Machine Room Less). Gearless elevators can travel about 2000 ft/min; however, even though geared have the same weight capacity, they can only travel at about 500 feet/min with a maximum travel distance of 250 ft.
Another type of elevator often used in this application is a Hydraulic Elevator for smaller buildings ranging from two to eight floors. There are two types, with one that has a telescoping piston at the base of the elevator pit, which allows the elevator car to travel up to 50 ft. Another type also uses a piston that doesn’t telescope but supports heights only up to 20 ft. Hydraulic elevators are capable of traveling up to 200 ft/min. Located on the lowest floor is a machine room with an electric motor that pumps hydraulic fluid down the piston, pushing the elevator car up. When the elevator is requested to descend, a value releases the hydraulic fluid from the piston.
In 2005, PVE (pneumatic vacuum elevators) launched their first elevator, which does not require cables or pulley systems. This elevator operates by using Air and the natural laws of physics. It is constructed with polycarbonate and aluminum materials and is a tube sealed in a vacuum. The elevator moves up and down because of the air above and below the elevator. When one presses the up button, the system decreases the pressure above the tube by sucking it out, thus forcing the tube to move up. Similarly, when a user depresses the down button, the reverse happens in that the pressure below the tube is decreased as air is put back into the top of the elevator car, thus causing the tube to lower.
Thus elevators have come a long way from bringing meals to dinner time; freight elevators, passenger elevators, and even vacuum elevators. Pneumatic Vacuum Elevators are perfect for homes that transport people via air pressure and do not require any pit at the bottom.
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