Post on 15-Apr-2017
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INTRODUCTION The hoisting is the lifting of the material against gravity and maybe done with a wide range of equipments from the small hand operated simple screw or hydraulic-jack to modern high powered cranes and elevators.
The common equipments used are as follows:
Pulley and sheave blockChain hoists Mobile cranesWinchJackShear legTower cranesWhirler cranesDerrick cranesGantry cranes
Pulley and sheave block A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a cable or belt along its circumference. Pulleys are used in a variety of ways to lift loads, apply forces, and to transmit power. In nautical contexts, the assembly of wheel, axle, and supporting shell is referred to as a "block."A pulley may also be called a sheave or drum and may have a groove between two flanges around its circumference. The drive element of a pulley system can be a rope, cable, belt, or chain that runs over the pulley inside the groove.
The pulley and sheave blocks suitable for lifting rough surface and heavy loads.For this purpose the chains and wire ropes are used.The alloy chains are best suited for hoisting operation.The weakest component of this system is the load hook. The hook fails by straightening. Once the hook gets elongated or straightened, it should be replaced.A typical sheave and pulley block is shown in fig.
Chain hoistsThe chain hoists are the popular mechanism for lifting loads upto tones.The system consists of two sets of chains, namely the hand and load chain.The hand chains are particularly useful for the isolated location , where an electric motor or other types of mechanical equipments are not available.The pull applied through the hand chain is transmitted to the load chain with a multiplication factor of over 20.
The load to be lifted is held by a load hook while another hook(called support hook) at the top, support the mechanism.The two hooks however ,should not be interchange as the support hook is made much stronger than the load hook.There are four types of hand operated chain hoists are in use:( 1) Differential (2)screw geared(3) spur geared (4) pull lift
Mobile crane is used in big construction projects for lifting heavy loads.It is used for loading and unloading for material in coal mines.Loading and unloading of ships.To take the load from ground level and place it into the trucks.
WinchA winch is a mechanism in the shape of a cylinder or drum, over which rope or chain is wound.If a winch is used only for raising and lowering, it is sometimes referred to as hoist.The winches are of two types :-(1) hand winches (2) power winches
These are the crane of swing job type and are mounted on high steel towers. The height of tower maybe 25 to 30 m and these cranes are found to be suitable in the construction of tall buildings in congested areas.The ground area required for such cranes is very small.
Whirler cranesThis crane is a combination of stationary and mobile unit. This combines the advantages of log boom of derrick crane and mobility of the mobile crane. The rotating structure has an outer framework.The boom is attached to the front end of this framework. The counter weight is provided at the rear end. On the diagonally opposite corners of the base, two separate motors are provided, which give movement to the central shaft.
Derrick cranesThe derrick cranes are of two types, namely:(1) Guy derrick and(2) Stiff leg derrickThe guy derrick consists of a vertical mast. This mast is supported by the number of guys and can revolve through 360.While revolving, the radius of revolution should be such that the revolving structure is not obstructed by the guy wires.The power is supplied by a diesel engine or by an electric motor.
A typical derrick crane is illustrated in fig.This derrick can be constructed upto 200 tonnes capacity .In stiff leg type derricks, the guy wires are replaced by trussed structure.This type of derricks are suitable for loads from 10 to 50 tonnes.
The Gantry cranes or overhead cranes are the indispensable machines in factories and workshops.In large workshops, there are separate machines for fabrications or repairs of the machine parts.The machine or the components, which are to be repaired, can be transferred to the place of fabrication or assembly with the help of Gantry cranes.
COSTING/ECONOMYPulley and sheave block :- 30000 - 120000Electric chain hoist 2 tonnes:- 30000 - 1200000Electric whinches :- 8400 - 300000 Hydraulic jack :- 30000 84000Overhead crane or gantry crane :- 360000 18000000Tower crane :- 6000000 1200000070 tone hydraulic crawler crane :- 1500000 18000000Elevators :- 600000 1800000
Fixed Derrick crane :- 1560000 2400000 Mobile cranes :- 1200000 3000000Truck cranes 7 ton :- 500000 - 1800000Truck mounted crrane 70 ton :- 12000000 - 18000000
ADVANTAGES OF HOISTING EQUIPMENTS Hoisting equipment assists in the lifting and positioning of large, heavy loads in a variety of industries, including:AutomotiveChemicalsCommercial printingManufacturingNewspaperPaperSteelWarehousing and distribution
Hoisting equipment provides a variety of benefits:
Customizable Hoisting equipment can be customized with below the hook attachments, end effectors or specialized tooling to handle a diverse variety of products and loadsErgonomics By doing the heavy lifting, hoisting equipment takes the strain off operators, reducing fatigue and lowering the risk of injuryFlexible Hoisting equipment can be easily re-fitted for longer lifting capability
Indoor/outdoor use Hoisting equipment can be used with equipment both inside a facility and outside, on the dock or in the yardLower maintenance costs Incorporating the latest technologies and offered in a variety of usage and capacity ratings, hoisting equipment requires less maintenance compared to other lifting devicesPortable Hoisting equipment can be easily transported from job to job or site to sitePositioning Highly automated systems maneuver with the precision of one thousandth of the rated speed to an exact location
Reduction in product damage By allowing for smooth, direct-path lifting over obstacleswith soft start features, multiple speed options and a variety of end effectors to interface with and secure the loadproducts are handled gently to minimize damageSafety Because they operate overhead and work in a specific area, hoisting equipment is less likely than forklift traffic to maneuver a load into personnel, walls, machinery or other obstacles
How is Hoisting Equipment Used?Hoisting equipment is used in a variety of areas to support processing and handling throughout a facility:
Assembly: Moving products through production processesPositioning: Securing a component for additional workTransportation: Loading finished products onto open trailers or railcars
Staging: Holding work-in-process for additional production processes
Storage: Transporting heavy items to and from storage areas
Warehousing: Moving large, heavy products to and from docks
DISADVANTAGES OF HOISTING EQUIPMENTSDisadvantage of chain hoist is slow lifting pace and limited places.Hydraulic engine hoist can take a lot of space in garage.Electric hoist are not good with heavier loads.electric hoist is that they need a special place to be installed.electric hoist will be static and cannot be moved around(without special installations), so you will always have to place a reparable car in the same place.
Electric hoist needs to be placed above the ground. This usually means mounting it to ceiling or building a special scaffolding to install an electric hoist.Another disadvantage of electric hoist is that it needs an electric power source in order to work. Hydraulic or chain engine hoists need to be operated manually, while electric hoist has got anelectrical motorthat works with an electrical power.electric hoist isfast and convenient tool to use for lifting moderately heavy loads, but becomes much more expensive, if you need to lift loads heavier than 225 kg(500 lb).
The lifting of load is also very slow in chain hoist.Thislifting process in chain hoist is slower than electric hoists or hydraulic hoists.The cranes used as hoisting equipments are expensive.
The climbing tower crane disadvantages:
Due to the direct support tower crane in the construction, the need for checking the structure, when necessary, temporary reinforcement, increased costs.
Due to the crane installed in the elevator shaft of the building, so the crane installation will affect the construction schedule basement structure. due to the crane installed in the elevator shaft of the building, so the crane installation will affect the construction schedule basement structure.driver communication links with the ground is difficult, driver vision is not enough open to lifting bring some security risks.after the project is completed, disassemble downstairs need auxiliary lifting equipment, difficult to disassemble, not safety.
MANUFACTURERS OF HOISTING EQUIPMENTSRoughneck Industries Neiko Enterpises Haulmaster IndustriesTorinBlackbull Goodway industries, GhaziabadTechno industries, AhmedabadHydraulic force Enterprises, delhiPower tech industries, LudhianaD.A.V. Engineering works, Ludhiana
Belt and Bearing house, AhmedabadTrophy Tech India, BengaluruSouthern Plantaids private Limited secunderabadSany Group, etc.
Hiring charges of hoisting equipmentsTruck mounted 70 tone crane :- 40,000/day Mobile crane 15 tone :- 10,000/dayChain hoist :- 5000/day T