Elevators
In a double-deck elevator, there are two attached cars, one on top of the other. They move together in the same shaft. The great advantage in a many-story building is that two adjacent floors can be served simultaneously, with half as many stops. The capacity of each shaft is doubled, cutting down on dedicated floor space on each story.
In some designs, one of the cabs serves as a freight elevator. During peak traffic periods, it becomes a second passenger car.
Worldwide, many double-deck elevators have been built, as many in Asia as in Europe and North America combined.
In densely populated areas where space is limited, multi-level parking lots have inclined ramps so that users can drive to the desired level. Some of these facilities have automotive elevators that carry cars and passengers to their destinations. Most of these are hydraulic elevators, and they must be rated for large loads to safely accommodate a heavy vehicle loaded with passengers and luggage.
Closely related are aeronautic elevators on aircraft carriers. Here considerable space is needed on deck for the runway plus nautical equipment, and that leaves room for only a few aircraft. Most of the 100 or so jets are stored in below-deck hangars, which is convenient for servicing and general maintenance. But how are they moved back and forth? Early aircraft carriers experimented with various methods such as moving the aircraft up and down inclined ramps, and using cranes to lift them. In the end, a nineteenth-century solution was adapted for this twentieth-century need, the hydraulic elevator.
In a typical aircraft carrier, most of the jets that are not in use are stored in the hangar bay, which is located two decks below the flight deck, directly under the galley deck. The hangar bay may be 110 feet wide, 25 feet high, and close to 700 feet long, over two thirds the length of the aircraft carrier. Besides aircraft, there is a large maintenance area with spare engines, extensive tools, and areas open to the outside for testing engines. Various sections are separated by sliding fire doors. There may be four gigantic aluminum hydraulic elevators, each capable of lifting two 30-ton jets simultaneously.
Stage elevators are essential for large theatrical productions. They permit elaborate settings to be assembled in advance, ready for action, and raised into place between scenes. Similarly, large orchestras complete with musicians and heavy pianos can be instantly deployed. These elevators are invariably hydraulic, with heavy steel-framed floors supported by massive pistons. Radio City Music Hall has four large stage lifts behind which are three smaller ones, so that sections of the set and orchestra can be moved as needed.
Residential elevators are used to transport elderly and handicapped persons between floors in their own homes, often permitting partially disabled persons to live at home for many years without relocating to a ranch-style building. These home lifts are permitted to be less complex, and they are generally slower and less powerful than commercial elevators, so the cost is far less. Safety systems such as shaft and car door interlocks, safeties, and emergency phones are required. ASME A17.l, Section 5.3 covers residential elevators. This category does not include elevators in multi-family occupancies.
Dumbwaiters are intended to carry light freight between floors, never human passengers. They are frequently installed in restaurants and hotels, to connect kitchens to dining rooms on higher levels. Because of the lighter, inanimate loads, some of the usual safety features are not required. The platforms are much smaller than those in passenger and conventional freight cars, with three-foot door heights. At each landing there is a control panel, permitting calling, door control, and choice of destination.
The Paternoster consists of a series of moving compartments. It resembles the humanlift, found in multi-story industrial buildings, where the rider stands on a small platform, gripping a handhold.
The scissors lift is a mobile work platform that allows maintenance workers and painters to easily access outside walls and inside walls in industrial building that have high ceilings. Scissors lifts are used extensively by electricians in servicing light fixtures in high-bay areas. They can also be used as long-term fixed elevators where there is no space for pit, machine room, counterweight, or hydraulic cylinder.
Rack and pinion elevators are powered by a motor-driven pinion gear. They are often installed on the outside of a building under construction, and can easily be moved to the next work site.
Belt elevators are used extensively to move loose material such as grain and coal. Typically the loads are moved up inclined planes. Pit mines make extensive use of these elevators. Vertical elevators in underground mines, used to transport materials, equipment, and workers, are often large, powerful, and challenging in terms of design, installation, and maintenance. Electrical systems are sometimes in areas classified as hazardous.
A survey of elevator types should include a description of the major elevator manufacturers. There are relatively few compared to the number of household appliance or automobile manufacturers. This is because elevator systems are very complex. They vary widely in height, with shafts, traveling cables, and steel ropes sometimes thousands of feet long. Often there are group installations of multiple powerful high-voltage electric motors and elaborate control and communication systems. The entire assembly has to conform to detailed safety codes, which vary depending on the location and elevator type.
Here is Wikipedia’s list of current elevator manufacturers. We will focus on a few of them:
■ Acorn Stairlifts
■ Aichi
■ Anlev Elex
■ Anton Freissler
■ Canton Elevator Incorporated
■ Cibes Lift
■ Delaware Elevator Manufacturing
■ Delta Elevator
■ FUJIHD
■ Fujitec
■ GEDA USA
■ Hitachi
■ Hosting Elevator
■ Hyundai Elevator
■ KLEEMANN
■ Kone
■ LG Elevator
■ Liftech SA
■ Marshall Elevator
■ MEI-Total Elevator Solutions
■ Mitsubishi Electric
■ Orona Group
■ Otis Elevator Company
■ Schindler Group
■ Servas ascensores
■ Sicher elevator
■ Sigma Elevator
■ Symax Lift
■ Stannah Lifts
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