Basic Elevator Components - Part Two



In the previous topic " Basic Elevator Components - Part One" , I indicate that the basic elevator components are as follows:


  1. Car. 
  2. Hoistway. 
  3. Machine/drive system. 
  4. Control system. 
  5. Safety system. 
I explained the elevator car components in this prevouis topic, and today I will continue explaining the second item from basic elevator components which is Hoistway as follows.

You can review the following prevouis topics for more information and good following. 


Second: Hoistway 


Hoistway is the space enclosed by fireproof walls and elevator doors for the travel of one or more el
evators, dumbwaiters or material lifts. It includes the pit and terminates at the underside of the overhead machinery space floor or grating or at the underside of the roof where the hoistway does not penetrate the roof. (Hoistway is sometimes called "hatchway" or "hatch".) 

Hoistway 

A simple definition for the hoistway is the shaft that encompasses the elevator car.

Note: Generally the Hoistway serving all floors of the building but in high-rise buildings hoistways may be banked with specific hoistways serving only the lower floors and others serving only middle or upper floors while traveling in a blind hoistway until reaching the floors that it serves. A blind hoistway has no doors on the floors that it does not serve.


Hoistway components:


Hoistway is equipped with the following components:

  1. Guide rails for both the car and counterweight.
  2. Counterweight.
  3. Suspension (Hoisting) Ropes (Cables).
  4. Landing (Hoistway) doors.
  5. Buffers in the pit.

1- Guide Rails 



Guide Rails

Guide Rails are Steel Tracks in the form of a “T” that run the length of the hoistway, round, or formed sections with guiding surfaces to guide and direct the course of travel of an elevator car and elevator counterweights and Usually mounted to the sides of the hoistway.

Car Guide rails are fixed to the hoistway by means of steel brackets 
which consists as shown in the below image

Car steel brackets

While counterweight guide rails are fixed to the hoistway by means of side steel brackets which consists as shown in the below image. 

counterweight  side steel brackets 

And the guide rails are fixed to these brackets by means of clips which usually have (3) types as follows: 

Guide Rails Brackets Clips


  1. (M Clips) Hot Forhed Clips. 
  2. (SL Clips) Sliding Clips. 
  3. (SH Clips) Combined Clips. 

Some special brackets are used in special cases as follows:

A- Combined Bracket: 

Combined Bracket

Combined bracket is used only when the arrangement of the lift equipments (Car and Counterweight) are too closed and perpendicular to each other in a specific point.

 B- Combination Bracket: 

Combination Bracket

Combination bracket is used to mount both rails of counterweight with one rail of the car as shown in the below image.


2- Counterweight 



Counterweight 

Counterweight is A tracked weight that is suspended from cables and moves within its own set of guide rails along the hoistway walls.

Counterweight is used for the following:

  • Balancing the mass of the complete car and a portion of rated load, and it will be equal to the dead weight of the car plus about 40% of the rated load. 
  • Reducing the necessary consumed power for moving the elevator. 


Counterweight components:

Counterweight components

The counterweight composed of a steel frames that can be filled with cast iron fillers above one another to get the required and it is usually composed of the following parts:

A- Top Part Assembly:
Top part consists of main bent sheet metal 4 mm and hitch plate 8 mm thickness for ropes attachment drilled with holes pattern to ropes size and quantity.

B- Bottom Part Assembly:
Bottom part consists of two halves made of steel 4 mm, the two halves are screw connected using vertical profile with buffer plate welded to one of the two halves, the buffer plate made of sheet metal 8 mm thickness to buffer the buffer loads.

C- Vertical Profile:
The vertical profile consists of U-shaped, bent sheet metal components. The vertical profiles are screw-connected to the upper and bottom parts.

Standard vertical profiles are available for 60 filler weights above one another, variable vertical profile lengths are possible for special versions.

The fillers can be inserted through the side cut in the vertical profile.

D- Filler Weights:
Filler weights are made of cast iron, there are standard lengths for fillers depend on the counterweight size and gauge. Ends of filler weights prepared to be guided in the vertical profile.

E-Guide Shoes:
The counterweight has a separate guide rails (as indicated above in the guide rails paragraphs) , which will keep counterweight running without twisting and avoid colliding with car or other lift components.

Sliding Guide Shoes 

The counterweight equipped with sliding guides to ensure smooth running along the travel height Variable gauges between counterweight rails are possible.



3- Suspension (Hoisting) Ropes (Cables) 

Suspension Ropes

Suspension Ropes are Suspension means for car and counterweight, which are represented by steel wire ropes.
They are Used on traction type elevators, usually attached to the crosshead and extending up into the machine room looping over the sheave on the motor and then down to the counter weights.
Hoisting cable are generally 3 to 6 in number. These ropes are usually 1/2”or 5/8” in diameter. 

The term Roping system can be defined as the arrangement of cables supporting the elevator and which has many types or arrangements as follows:

Roping system


  • Single wrap: rope passes over sheave once and connected to counterweight. 
  • Double wrap: rope wound over sheave twice in high speed elevators for additional traction.
  • 1:1 roping: when rope connected to counterweight where cable travels as far as car in opposite direction. 
  • 2:1 roping: rope wraps sheave on counterweight and connects to top of the shaft, rope moves twice as far as cab.

Note: A variety of roping systems can be employed dependant on the particular conditions of each and which are summarized in the below image. 


4- Landing (Hoistway) Doors

The door that is seen from each floor of a building is referred to as the outer or hoistway door. This hoistway door is a part of the building (each landing). It is important to realize that the car door does all the work; the hoistway door is a dependent. These doors can be opened or closed by electric motors, or manually for emergency incidents.

Safety devices are located at each landing to prevent inadvertent hoistway door openings and to prevent an elevator car from moving unless a door is in a locked position.

The difference between the car doors and the hoistway doors is that the elevator car door travels through the hoistway with the car but the hoistway doors are fixed doors in each landing floor.

Hoistway Door Types:


There are four basic types of hoistway doors used on elevators as follows: 

Hoistway Door Types

  • Automatic Door: Center opening doors consist of two power operated panels that part simultaneously with a brisk, noiseless motion.
  • Swing Door: Swing hall doors consists of a hoistway door that is manually opened and a single slide car door that is power operated.
  • Telescopic Door: It consists of two power operated panels that are geared together. One door moves twice as fast as the other door so that both doors will meet concurrently in the open position. 
  • Collapsible Gate: Constructed from double channel rolled pickets 16mm wide x 2.5mm thick interconnected by 6mm thick galvanized steel solid lattice bars. 

Hoistway Door Interlock 

Hoistway Door Interlock 

The hoistway door locking mechanism provides a means to mechanically lock each hoistway door. They are also interconnected electrically to prevent operation of the elevator if any of the elevator’s hoistway doors are open.

Hoistway Emergency Door Keys

Hoistway Emergency Door Keys

Hoistway Emergency Door Keys permit the unlocking of the hoistway door interlock.


Escutcheon Tube

Escutcheon Tube

The keyhole on the upper portion of a hoistway door that accepts a hoistway emergency door key and permits unlocking of the hoistway door locking mechanism.

These keyholes are usually located at the bottom and top floors, but may also be on other selected floors or all floors.

You may find a lock covering these keyholes on some new elevator installations. Locate these keys during pre-fires. 


5- Buffers in the pit

A Buffer is a device designed to stop a descending car or counterweight beyond its normal limit and to soften the force with which the elevator runs into the pit during an emergency. They may be of polyurethane or oil type in respect of the rated speed.

There are two principal types of buffers in existence:

  • Energy accumulation: accumulate the kinetic energy of the car or counterweight. 
  • Energy dissipation: dissipate the kinetic energy of the car or counterweight. 

Polyurethane buffers which are energy accumulation type with non-linear characteristics are used for our lifts that have rated speed not more than 1 m/sec.

Polyurethane buffers have three shapes as shown in the below image.


The main types of elevator buffers are: 

types of elevator buffers

  • A Spring Buffer is one type of buffer most commonly found on hydraulic elevators or used for elevators with speeds less than 200 feet per minute. These devices are used to cushion the elevator and are most always located in the elevator pit. 
  • An Oil Buffer is another type of buffer more commonly found on traction elevators with speeds higher than 200 feet per minute. This type of buffer uses a combination of oil and springs to cushion a descending car or counterweight and are most commonly located in the elevator pit, because of their location in the pit buffers have a tendency to be exposed to water and flooding. They require routine cleaning and painting to assure they maintain their proper performance specifications. Oil buffers also need there oil checked and changed if exposed to flooding. 


Main Electro-mechanical requirements in Hoistway: 

Hoistway Pit

  • No light is required at the top of the hoistway as the car top is equipped with a standard caged light fixture for use by the mechanic during his maintenance visits.
  • GFI duplex receptacle is required in the pit for use by the mechanic during his maintenance visit. 
  • Ladder shall be provided and extend 48" above the pit access floor or as instructed by the consultant. 
  • Light must have an external guard and be located at a point where illumination on the pit ladder base is no less than 10 foot candles. 
  • Light switch must be accessible from access floor and ladder. 
  • Pit must be clean and dry. A drain or sump pump is required. Sump pump recess must have a metal cover. 
  • Smoke detectors are required in hoistways if sprinkled. 
  • Only machinery, equipment, electrical wiring, raceways, cables, coaxial wiring, and antennas used directly in connection with the elevator, including wiring for signals, for communication with the car, for lighting, heating, air conditioning, and ventilating the car, for fire detecting systems, for pit sump pumps, and for heating and lighting the hoistway and/or the machinery space machine room, control space, or control room shall be permitted to be installed inside the hoistway, machinery space, machine room, control space, or control room.


In the next Topic, I will continue explaining the Basic Elevator Components. So, please keep following. 


Note: these topics about elevators in this course EE-1: Beginner's electrical design course is an introduction only for beginners to know general basic information about elevators as a type of Power loads. But in other levels of our electrical design courses, we will show and explain in detail the Elevator Loads Estimation calculations. 




8 comments:

  1. plz give the control circuit diagram for four floor lift using proxy sensors and relay.

    ReplyDelete
  2. Whats the standard hydraulic elevator pit dept, is it 2 4 or 6 feet

    ReplyDelete
  3. im interested in pit bottom beffers design anmd supply, please advice

    ReplyDelete
  4. good information for this helpful to others ..please keep on do your regular update ..thanks by mydeen....

    ReplyDelete

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