ELEVATORS

LIFT :-

Lift is an appliance by which persons and goods are moved vertically from one level to another. A passenger lift is designed to carry persons. Goods lift or hoist servers are primarily used to transport the material. A platform lift is used for transporting the materials. It has a platform or floor unlike a car. It has neither sides nor door.

1. Lift pits: – Minimum depth of lift pit required is 1.5 meter. The lift pit should be completely watertight. M.S. ladder to be provided for access to the lift pit.
2. Buffers: – Oil type or spring type buffers are fixed at the bottom of the pit . It should be in line with the center of the car and other in line with the counter weight, at the extreme lower limit of travel.
3. Lift car: – The unit, which carries the passengers. It has a steel frame which supported on the floor or platform in addition to side & top bodywork & to which the safety gear, guide shoes & suspension ropes are fixed.
4. Counter weight: – A unit consisting of steel weights which counter balances the self weight of the car and part of live load. The suspension ropes are attached to the counter weight.
5. Diverting pulley: – A wheel situated at the top of the shaft and below the driving sheave, which serve to bring the suspension ropes directly over the counter weight.
6. Driving sheave: – A wheel with V- shaped groove on its face the suspension ropes pass over & in the wheel the power from the lift machine is transferred to the wheel through the wire ropes.
7. Guide Rails: – These are fixed vertically in the shaft are of steel material and serve to guide the movement of both car and counter-weight.
8. Controller: – A group of device mounted on a panel, which governs the motion, direction, travel steep
9. and stopping of lift car.
10. Door closer: – A device, which closes the door automatically.
11. Landing call push: – A push button provided at landing for activating the call indicators.
12. Top clearance:- Adequate clearance shall be maintained between the top of the car ( when it is on top floor ) and the bottom of the diverting pully.
13. Template: – Template is a right angle frame of wood or M.S. angle, which is kept on two supports at the top of the lift shaft from which the plumb strings are suspended. For maintaining the verticality of the guide rails and body of the car. It also helps in deciding the position of the pockets.

Types of elevators: –

1. Passenger lifts: – For carrying passengers from the residential and commercial building.
2. Stretcher lift: – For hospital use.
3. Goods lift: – Use in factories to carry goods.
4. Hydraulic lifts: – Used for the buildings and bungalows with inadequate space for lift room.
5. Dumb waiters: – Used in hotels & Hospitals use.

Civil work required for lift:

1. Waterproofing to be done to the lift shaft below ground level from outside by fixing rough Shahabad tiles.
2. Minimum depth of 1.5m is to be kept below the F.F.L.of the bottommost stop.
3. Fix M.S. ladders for access to the pit
4. Make scaffolding as per the specification given by the erector & fix the template.
5. The surface walls of the lift shaft should be cleaned, free from any projections and finished smoothly.
6. Apply white wash to all internal faces of lift shaft.
7. Face walls of the lifts should be 230mm thick brickwork. The brickwork should be in plumb and right angle. Fix all the door frames except GF/basement levels frames in plumb and as positions given by the erector.
8. Plaster the above wall from both sides in line, plumb and right angle. The external face of the wall may be rough plaster for cladding work.
9. The ground floor/ basement level brickwork and frame fixing should be done after the lift car is installed.
10. Do the cladding work after completing the plaster.
11. Construct the machine room as per drawing, ensuring proper ventilation.
12.  Finish the machine room floor with IPS after all the wiring and raceways are completed.
13. Do the painting of machine room.
14. Fix shutter of machine room and keep it locked.

Electrical work: –

A three-phase & single phase connection is required in the lift machine room for which armored cable are run on the back wall of the lift shaft. A light point & a 3 pin socket at each floor level & are provided in lift shaft. Provision of a lift point & 3 pin socket is made in lift pit also.

Safety gear: –

Every passenger & goods lift must be provided with an emergency stop switch, a press button alarm & automatic safety gear on the car, which in the event of rope failure will stop and sustain the pulley-loaded car in the guides. Such gear is fitted below the platform and between the car guide nails. For slow speed lifts the gear should be quick acting and for high-speed lifts it must be more gradual in action. Details differ but essentially guide rails are gripped by the mechanism sufficiently to stop the car during its decent.

Over speed Governors: –

This is a form of safety gear, which operates when a descending car exceeds the predetermined maximum speed. It must be fitted to every lift having a travel exceeding 6 meters and is situated near the top of the shafts. A steel or bronze rope connected to the safety gears described above is passed over the pulley of the governor, continued down the shaft and passed under a pulley fixed in the pit and up to the car to which it attached. If the car during it’s decent exceeds the maximum speed, the governor comes into operation to lock the rope and thereby bring for operating the safety gear.

CHECKLIST: –

1. Check the depth of the lift pit as per standard dimensions given
2. Check the lift shaft for the right angles and plumb.
3. The interior specifications of car
4. The threshold of the lift door should be above the landing floor level. The slope of landing tiles should be away from the lift door.
5. Check the emergency light and bell are working.
6. Check whether all indicators are working or not.
7. Check whether Instruction sheets are fixed in the machine room and lift car.