施工升降机的创新设计英文介绍.doc

The Innovative Design of Construct HoistJia Wenhua,Yin ChenboInstitute of Automobile and Construction Machinery,Nanjing University of technology,Nanjing 210009,P.R.ChinaAbstract In this paper,the current development of construction hoist is reviewed.The structure and the characteristics of the construction hoist are described.The key technologies such as the structure of the diversity of the construction,the traction-lift construction,the integrated winch system and the computer aided design are discussed.Keywords Construction machinery hoist;Innovative design; Electro-hydraulic.1 IntroductionThe construction hoist is a kind of mechanical machinery used to lift passengers and materials along the vertical or rail-dumping mast.It is composed of platforms,hopper ,cage and so on. It can help to improve productivity and reduce costs. To meet the needs of different kinds of constructions,many new types of construction hoists have sprung up which have advanced functions.2 Innovative design of structure2.1 Common structureConstruction hoists can be divided into four types according to the number of cage and mast. Their relative position is shown in Fig.1. a b c d(a) double mast and single cage(b) Single mast and cages on both sides(c) Single mast and a cages in one side (d) Single mast and a cage insideFig.1 Common structure diagramThe hoists have been widely applied in construction to enhance productivity and construction costs greatly. The standard sections of hoists with either single mast sections or double mast sections are all connected by bolts,and fixed on the wall by connections.There are mechanical springs fixed on the bottom frame of this in order to increase the reliabilities.2.2 Several new types of structureThe tilt hoist has rail-dumping masts,which can be applied where the building is not vertical.Its mast is parallel to the fade of buildings.It is widely used for chimneys,towers,bridges and other high-rise tilt buildings.One folding and removal hoist for low-rise buildings has emerged in recent years.He folding and removal hoist made by German BOCKER and it has a good performance.This hoist can pass through narrow passenger ways,when the structure is compact.The rail sections of this hoist can rotate 360 around the base,operating easily and efficiently.Furthermore,the rail sections can be extended and bended so that materials can be transported conveniently to the roof of the buildings.According to those superiorities,this type hoist will be applied widely in low-rise buildings.To adapt the trend of energy-saving and safety,the effective ways to optimize the machinery hoists are reduction of self-weight and diversity of product forms.The MB-hoists made by Italy MABER has a trilateral cross-section mast.This type of mast sections can reduce self-weight but not lower performance,and it can reduce cost and be installment quickly and easily.The CM-double mast can share the mast with other cage or platform,so that it overcomes the problem of low utilization about the traditional double mast hoist,increases the load capacity.In general,this type hoist is suitable in the large-scale buildings for material or passenger.3 drive system innovative designThe drive system is the core part of a hoist,and it plays a significant role in the advanced,safe and comfortable characters of a hoist.3.1 Rack-and-pinion gears drive systemUsing rack-and-pinion gears,the drive system has high efficiency and reliability.There are two types of connection between the cage and the drive system.The first type is that the drive system arranged within the cage.It is fastened on the hoist,driving the hoist moving directly.Another is that the drive system arranged upon the cage,it is connected the cage by pins,drawing the hoist moving indirectly.The form of the elastic fixing is simpler than of the rigid fastening and can compensate for the influence and can compensate for the influence of rack-and-pinion gears,these influences incurred by the error of the production and assembly. The elastic fixing can also avoid of the damages of the drive system and play a buffer so that the hoist has a stable brake.3.2 Traction drive systemThe drive system is driven by the tractor,and the speed reducer outputs the torque to the dray round.The tractor driver through the ropes and the dray round the hoist moving.The tractor has two types of relative placement,underneath type and top-installed type.Because of the complex of the structure and the higher cost,the underneath type has not been applied widely.As show in Fig.2,the manned hoist with top-installed traction machine developed by the authors of this Fig.2 Manned with top-installed traction machinepaper,whose tractor is fixed on beam.This hoist uses the over-speed governor and the safety gears.When the speed reaches or surpasses a given value,the over-speed governor will stop and pull the safety gears to move in the mean time,the cage is stopped on the mast.For this type hoist,the problems about the complex structure and cage crashing were solved.Because of all of these advantages,this new type hoist will be applied widely.3.3 Integrated winch drive systemThe winch is a non-continuous working machine,starting and braking frequently.Its safe operation is very important for the hoisting.To avoid various steel wires of mutual rubbing and multi-winding piling up,the winch should establish a rope arranging device,and the rope distance is slightly bigger than the wire diameter.Meantime,the wire winding height of the drum between the outer sides should have a certain safe altitudes.This height should not be smaller than 2 times of the wire diameter.The voltage frequency converter system has been used in winch drive system.Using the VFC system,it is not only can simplify the wiring control but also can adjust speed conveniently,so that the hoist has a strong mechanical properties,high precision control and low electricity consumption.With the development of the integrated mechanical technology,the winches are no longer assembled in independent modules and series completed,but to use the electro-hydraulic technologies to be assembled a computer unit.Using the integrated winch,the system can achieve the given movement and function accurately,leading to the reliable,compact,high performance and energy saving purposes.The integrated winch integrates the motor,brakes,drive gears,coupling as a whole.At present the biggest integrated winch is installed in the Western Mimings Olympic Dam in Australia.About this integrated winch,the motor os installed in the drum,and something such as the motor or the gear box is not on the outside.The winch and the related systems were designed and made cooperatively by German Demag GHH Company,Australia Cegelec Company and Man GHH Company.3.4 Hydraulic driveThe hydraulic drive is a later development technology relative to mechanical drive.With the increasing demand of computer technology as well as other advanced technologies,the hydraulic technology is developing rapidly and is seeping to various industry areas.The elector-hydraulic technology is becoming the mainly studying field.To the engineering machinery,electro-hydraulic product is a integrated product collected by hydraulic,mechanical and electronic device.One type hoist made by German PAUS is composed by power unit,driving unit and operating device.Its electro-hydraulic technology is mainly represented in the electronic control of the total hoist,electro-hydraulic drive,manipulation,remote control and so on.The hydraulic and electrical control technology is coordinated conveniently to realize the procedure movement.By controlling the work fluid the hydraulic pump and the solenoid electric valve complete the actions,either the leg cylinder movement or the rack cylinder to expand and contract or two motors movement,then the two motors impetus the winches to drive the cage movement.Microprocessor control systems can remote control the hoist timely action,safely and reliably.4 Computer aided innovative designThe rapid development and popularization of the computer technology has laid a strong foundation for the construction hoists.Such as 3D model design,Optimization Design,Finite Element Analysis and so on.To avoid of forming isolated“island”of modern designs,the integrated design emerges.4.1 Application of integrated design technologyThe integrated design technology is based on the parallel design processing,breaks the serial pattern traditional product development process.Standing on the product design and manufacturing process,the integrated design considers all of the related process to complete th ee product process efficiently.Fig.3 is the integrated design system flow chart which has been designed by the authors of this paper.In CAD the structure is designed,then the finite element analysis in Fig.3 Flow diagram of integrated design systemCAE will be used and the kinematics and dynamics simulation will be taken on.If the results are not up to the design requirements,they should be redesigned,until the results meet the requirements.Next they are transmitted to CAPP(Computer Aided Process Planning)to be planned,then to CAM(Computer Aided Manufacturing)to be production simulated and to be assembly simulated based on DFA.This integrated design will be used to shorten the cycle of the production development and to reduce the costs.Among these technologies,the 3D design and the finite element analysis are the key part of the product design.4.2 3d model design 3D model is easy to understand and is intuitive,but also can prepare for the other follow-up treatments.It has run through the process of the design and production instead of acting as an assistant role.The method of 3D model has been used in the software of the computer aided design which has been developed by the authors.It is so difficult to express clearly the mast tie of the hoist by 2D map (Fig.4) so that workers only can rely on experience in welding and assembling.Fig.4 2D map of mast Fig.5 3D model of mast tieHowever,then 3D model will be able to overcome this disadvantage smoothly.As shown in Fig.5,the 3D model has expressed the mast tie obviously to improve productivity and reduce labor intensity successfully.4.3 Finite element analysisThe finite element analysis can be considered as an effective way to solve complex practical engineering problems which cant be solved by theoretical analysis.In this paper,the hoist has been analyzed by the finite element.That shows that the deformation of the mast section close to the top or the mast tie is smaller than the other.After finishing the static structural analysis,the comparison between the conclusion and the design requirements will determine whether to continue or to renew the process so that the design of the failure rate is minimization.5 ConclusionsIn this paper,the structure of several typed of m