Design

Some^[who?] argue that lifts began as simple rope or chain hoists (see Traction elevators below). A lift is essentially a platform that is either pulled or pushed up by a mechanical means. A modern day lift consists of a cab (also called a "cage" or "car") mounted on a platform within an enclosed space called a shaft or sometimes a "hoistway". In the past, lift drive mechanisms were powered by steam and water hydraulic pistons. In a "traction" lift, cars are pulled up by means of rolling steel ropes over a deeply grooved pulley, commonly called a sheave in the industry. The weight of the car is balanced with a counterweight. Sometimes two lifts always move synchronously in opposite directions, and they are each other's counterweight.

The friction between the ropes and the pulley furnishes the traction which gives this type of lift its name.

Hydraulic lifts use the principles of hydraulics (in the sense of hydraulic power) to pressurize an above ground or in-ground piston to raise and lower the car (see Hydraulic elevators below). Roped hydraulics use a combination of both ropes and hydraulic power to raise and lower cars. Recent innovations include permanent earth magnet motors, machine room-less rail mounted gearless machines, and microprocessor controls.

The technology used in new installations depends on a variety of factors. Hydraulic lifts are cheaper, but installing cylinders greater than a certain length becomes impractical for very high lift hoistways. For buildings of much over seven stories, traction lifts must be employed instead. Hydraulic lifts are usually slower than traction lifts.

Lifts are a candidate for mass customization. There are economies to be made from mass production of the components, but each building comes with its own requirements like different number of floors, dimensions of the well and usage patterns.

Elevator doors

Elevator doors protect riders from falling into the shaft. The most common configuration is to have two panels that meet in the middle, and slide open laterally. In a cascading configuration (potentially allowing wider entryways within limited space), the doors run on independent tracks so that while open, they are tucked behind one another, and while closed, they form cascading layers on one side. This can be configured so that two sets of such cascading doors operate like the center opening doors described above, allowing for a very wide elevator cab. In less expensive installations the elevator can also use one large "slab" door: a single panel door the width of the doorway that opens to the left or right laterally.

Machine room-less

General

All elevators, whether traction or hydraulic, have required a machine room to store large electric motors (or hydraulic pumps) and a controller cabinet. This room is located above the hoistway (or below, for hydraulic elevators) and may contain machinery for a single or a group of elevators.

Machine room-less elevators are designed so that most of its components fit within the shaft containing the elevator car; and a small cabinet houses the elevator computer. The traction rope is configured for force multiplication in a complex pulley system. In this configuration, the traction motor moves more rope per distance traveled, but works half as hard due to force multiplication factors of the pulley system.

This new design was first developed by Kone in 1996.

Benefits

• creates more usable space
• uses less energy (70-80% less than hydraulic elevators)
• uses no oil
• all components are above ground (this takes away the environmental concern that was created by the hydraulic cylinder being stored underground)
• much lower cost than other elevators
• ride quality is better due to gearless traction
• operates at faster speeds than hydraulics

Facts

• Noise level is at 50-55 dBA (A-weighted decibels), which is much lower than other types of elevators
• Usually used for low-rise to mid-rise buildings
• The motor mechanism is placed in the hoistway itself
• The US was slow to accept the MRL Elevator because of codes

---national and local building codes did not address elevators without machine rooms