- Due to space constraints and compact building designs, elevators and lifts are often required in multi-story buildings.
- On a single walk, an average man can only go up to a height of 30 meters before needing a break for the rest of the way up.
- However, as the practice of going up and down stairs becomes more common, buildings with a height exceeding 14.5 meters (or four stories) will almost certainly have elevators installed.
- Escalators, which have moving steps, are required for traffic rates of more than 3200 people per hour. If the building is very tall, elevators can account for 10-15 percent of the total construction cost.
So now let’s look to a list of lift parts more closer.
I. Components of the lift
An Elevator for Passengers: Design and Section
1. A stairway or elevator shaft
- Unless it is part of the lift, there should be no other equipment in the lift well.
- The lift’s internal surfaces should be completely smooth.
- RCC at least 15cm thick may also be used to construct the lift’s side walls.
- At the very least, the lift shafts that surround the stairwells must be fire resistant for two hours.
- A half-hour-resistance smoke stop door will be used to exit the lift lobby.
2. Machine room
- There is a machine room in which all lift drive and control devices are kept.
- The machine room should be located as close to the lift as possible, which has numerous benefits, including reduced load.
- For the same lift car size, a smaller lift well and lower power consumption are all advantages over a basement machine room.
3. Lift pit
When the car’s speed increases, so does its weight, resulting in a greater depth in the lift pit:
- a minimum of 1.6 meters of pit depth
- The lift pit should be waterproofed
- A ladder 0.75m above the pit floor should be provided if the height exceeds 1.6m.
- On the basis of vehicle speed and weight
- A minimum of 4.8 meters in height is required.
- It’s the distance from the bottom of the machine room to the finished floor level of the last landing.
- Assisting drivers in the event that their vehicle or the governing rope fails or overspeeds as a result of high voltages.
5. A counter-weight system
In order to counterbalance the lift car’s weight and rated load, these weights are attached to one end of the rope.
Gives the vehicle and counterweight a path to follow. It also keeps them where they are. Empty cage weight plus 40% to 50% of the counter weight is the counter weight.
Lift car overruns or rope failures can cause the lift car to slam into the lift pit floor, which is why the floor of the lift pit has been reinforced.
- In a building, lift cars are used to raise and lower passengers by means of transaction force generated by the lift driving machinery, which is invariably an electric motor.
- In order to maintain balance, counter weights are provided at the other end, which add 40 to 50 percent to the vehicle’s rated capacity. To reduce tractive effort, counter weights are provided.
- A motor, its brake, and a drum or pulley are the basic components of the driving machinery. Depending on the transmission method, a lift can be categorized as one of the following:
- Drum type:
- There are two number ropes attached to a drum and a counter weight in this system, which connects the car to the driving system
- The drum is a spool-like device on which the rope’s ends are wound and unwound during the car’s motion.
- A variety of mounting options are available for this system.
- Slow-speed elevators are the only places where drum-style elevators are still in use.
- Transaction type:
- Pulleys and counter-weights are connected to the ropes in this type of elevator.
- Friction between the rope and a pulley (traction sheaves), over which ropes roll, is used to transfer tractive force to the rope. There is
- an electric motor attached to the pulley that makes it turn.
- The drive motor can be directly connected to the traction pulley, or it can be linked to another gear, resulting in a lift that is either gearless or geared.
- Drum type:
Elevators with electric traction but no gears
- Buildings of any height could use the gearless traction electric elevator, which could operate at much higher speeds than steam-powered ones.
Elevators in this category typically travel at a rate of more than 500 feet per minute.
These ropes, known as hoisting ropes in the industry, are woven around the drive sheave of a gearless traction machine using special grooves. As a counterweight moves up and down in the hoistway, the other end of each cable is attached to it.
The cables on the drive sheave get the traction they need when the sheave turns because of the weight of the elevator car and the counterweight.
Lifts powered by gears
- The hoisting sheave is rotated by a wormand-gear reduction unit, as implied by the design’s name. As a tradeoff for the slower lift rates, a less powerful motor is needed to turn a sheave in a gear reduction elevator.
- These elevators are capable of carrying loads of up to 13,600 kilograms at speeds ranging from 125 to 500 meters per minute (30,000 lb).
- The elevator is stopped by an electrically controlled brake between the motor and the reduction unit.