A lift is a system permanently installed that serves for vertical (or in the direction smaller than 15% from perpendicular) transport of persons or goods in lift cars or on platforms.
Total shaft height Hs
Hs = Pit + Travel + Overhead
Note: dimensions concern the finished stop floors.
It is a load in kg that has been assumed for the drive calculations. The calculative load is the value that has been assumed for strength calculations of key bearing elements and usually it is the weight of maximum number of persons who a lift holds on a lift car defined area. There is a close relation between the load, a maximum number of persons and the area. For example, the load of 630 kg is the number of maximum 8 persons that is limited by the lift cabin area equal to 1,54 m2 (1,1 x 1,4 m). In case of passenger lifts the nominal load is equal to the calculative load whereas in case of goods lifts it is admissible to reduce the nominal load in relation to the calculative one resulting from the lift cabin area. For more information see EN 81-1/-2 standards.
Hydraulic lifts : the lift drive unit is composed of a tank, a hydraulic pump and an electric motor and starts a piston that through a direct ratio of 1:1 or through an indirect one of 1:2 (a rope pulley and ropes) drives the lift cabin.
Lift with a central pistonLift with a lateral piston
1:1 (with technology GMV SWEDEN ABTM 1:1)
GPL® Goods-passenger lifts GPL® Goods-passenger lifts
1:2 (with indirect roped drive)
Lift with 1 pistonGoods-passenger lifts with 2 pistons
The hydraulic lift’s machine room is not adjacent to the shaft and can be located in a distance from zero to several or even a dozen of meters from the shaft. Most frequently it is a free standing cabinet (so called machinery cabinet) or a separate room (a traditional machine room). There also exist hydraulic lifts without a machine room with a drive situated in the pit.
Traction lifts : the lift drive unit that is composed of an electric motor and a friction wheel coupled with it, drives the ropes connected with the lift car frame and a counterweight. There is distinguished a direct drive of 1:1 and an indirect one of 2:1 and 4:1 used in traction goods-passenger lifts.
Cabin: a lift unit designed for transportation of persons and/or goods.
Shaft: a space in which the lift cabin moves. The space is as a rule housed with pit bottom, walls and ceiling.
Machine room: a room in which the drive unit (or units) and the connected equipment are situated, e.g. control elements.
Drive unit: a unit that contains motor that drives a lift. In traction lifts it is so called traction machine and in hydraulic ones it is a set with a motor, pump and valve block.
T-guides: rigid elements that secure guiding of a car frame and a cabin.
Car frame: a rigid construction that holds the car and travels in the guides.
Counterweight: a separately guided mass that partly counterbalances the cabin and secures ropes pressure to a driving pulley.
Controller: a unit that controls the lift travel.
Piston: a lift component that uses a working medium for a plane motion. The piston is composed of a cylinder and a ram. There are also single or multistage pistons so called telescopic.
Passenger lifts - serve for transportation of persons.
Hospital lifts - are designed for transportation of persons and hospital beds together with medical equipment and personnel. They are characterized by accurate minimum cabin dimensions and door width as well as some functions such as “privileged travel”.
Vehicle lifts - are designed for transportation of vehicles. They are characterized by accurate minimum cabin dimensions and door width.
Goods-passenger lifts - are designed for transport of goods and persons accompanying the goods.
Goods lifts - is a group of lifts without a right to enter for persons. It is obtained by strict restrictions regarding the usage or by reduction of car dimensions (so called “small goods lifts”).
Special room - accessible only for the authorized persons - which contains the lift drive unit and equipment related to it, e.g. lift controller.
The shaft means the space in which a lift car moves. The shaft has usually a pit, walls and a ceiling. Depending on the lift type, in the shaft can be situated a drive unit, a counterweight and controller.
A lift’s unit serving for safe transportation of persons and/or goods.
1-opening - a cabin with a single entrance.
2-opening - a cabin with 2 opposite entrances.
Angle cabin - a cabin with 2 entrances situated at an angle of 90°.
Three-entrance cabin - a cabin with 3 entrances.
Lift doors are divided into landing (shaft) doors and cabin ones. The doors exist in two basic variants: central and telescopic (two or multipanel).
Central door - during opening / closing, the panels move in opposite directions.
Telescopic door - during opening / closing, the panels move in the same direction.
Telescopic door right - during opening the panels move to the right side
Telescopic door left - during opening the panels move to the left side
Swing doors - operated manually and are no longer used in newly designed lifts.
These are lifts of repeatable components and the shaft horizontal dimensions (width x length), and differ only in the number of stops and travel height. Thanks to the above fact, architects have easier task during a shaft designing and the risk of error is reduced.
(Tailor Made Lift). These are lifts of unrepeatable features and that is why they are designed individually to a given order. For example, lifts in existing shafts of atypical dimensions, panoramic with glass cars or lifts with 2 entrances to a car at an angle of 90o and even of 3 ones.
The lifts of full dimensions of shaft, pit and headroom.
Considering the shaft’s existing environment it is admissible to reduce the pit or the headroom, however with use of additional safety devices for lift fitters and maintenance technicians. For more information consult PN-EN 81-21 standard.
The building regulations require adaptation of passenger lifts for disabled persons. The basic requirements are minimum car dimensions (width x length) 1,1 m x 1,4 m, the door width of 0,9 m, push buttons marked with the Braille alphabet and voice information. Detailed requirements are defined in PN-EN 81-70 standard.
Ratio - is a basic parameter of a lift drive unit that enables increasing/decreasing of input speed in order to increase the torque / linear range of a lift operation. The higher ratio is the higher cabin’s sensitivity to instantaneous load. While in passenger lifts it is not so essential because a person entering the cabin is of 75 kg of average, in goods-passenger lifts it is very important. A forklift entering a cabin can load the floor with a force even of several tons and that is why it the hydraulic drives of 1:1 ratio is highly recommended. That means the direct supporting the cabin by pistons in order to obtain exceptionally stable floor during the loading. The hydraulic lifts of 1:2 ratio and traction ones of ratios from 2:1 up to even 4:1 are characterized by considerably worse stability during entering / exiting of passengers and particularly bad during loading with heavy goods.
Collective function - enables storing of a lift call commands in a memory by users and their execution by picking up the passengers going in the same direction. In multi-family apartment buildings a collective down is used (a lift picks up passengers going to a ground level) while in office buildings a collective up/down is usually applied. During going up a lift picks up successively passengers who want to go to higher floors while when going down it picks up persons who want to go to lower floors.
Reaction to electricity failure - in case of electricity failure (blackout) a lift should reach a nearest or lowest stop and open doors automatically to free passengers. Unfortunately, most of manufacturers use this solution as an option at high extra charge.
Operation in group - lifts that are located in a close neighborhood should operate in a group and a call regards one lift – that one which is closer to a calling person.
The cabin is a moving unit of a lift, which is loaded by persons or goods. The most unfavorable situations occurs at a time when on the sill of empty cabin appears a force Fs. The design of key structure elements should be strong enough to withstand forces and torques (Ts). Standards EN 81-1 and EN 81-2 recommend the use for the calculations the following values depending on the capacity Q:
Note: despite above requirements included in the lift standard, many manufacturers are not able to provide lifts with the right force values on the cabin’s sill. One should pay particular attention to it at the stage of selecting the right solution.
Every lift system emits noise during operation. However, use of a suitable lift type, the shaft correct construction and its location can considerably reduce noise emission in a building and inconvenience for the people staying in.
Hydraulic lifts are characterized by low noise level thanks to the drive unit location (power unit) outside the shaft: in a prefabricated engine room or in a separate room. It is worth to pay attention that the drive works only during going up. Going down is executed by the gravity force with the power unit off.
Traction MRL-type lifts without a machine room have drive in the shaft. This makes the noise emission going easier through the building. To reduce the noise inconvenience, the lift shafts are separated from the apartments with additional shaft concrete walls (dilatation) or the lifts are located in the central part of a staircase. Both methods waste a building internal space and require an additional energy-consuming heavy concrete construction.
Hydraulic lift with typically located power unit.
Travel up / down
MRL-traction lift without machine room and power unit located inside the shaft.
A very important parameter for designers and constructors. Greater weight means robust shaft’s construction and solid foundations as well as it has a bigger negative impact on the environment.
Electric lifts can be up to twice heavier than the comparable hydraulic ones.
WEIGHT COMPARISON OF LIFTS READY TO DISPATCH FROM THE FACTORY
Hp = 10 m, 4 stops