Chain Block lifting mechanism

We often say that the Chain Block lifting height differ in the lifting mechanism, the lifting mechanism of what is, what the specific differences,
Wire rope electric hoist lifting mechanism comprises a lift hoist motor through the shaft coupling through the reducer hollow axle driving drum rotation, so that the wire rope around the drum driven by a rising or falling hook device.
Lifting height H=6m, with a jaw coupling is connected to the motor shaft and reducer input shaft. H ≥ 9m is added in the intermediate shaft and the rigid coupling. H ≥ 18m, with support to strengthen the intermediate shaft rigidity, guarantee the smooth rotation.
electric hoist with trolley structure: motor, gear box, drum, steel wire rope, hook
Motor drive gearbox the drum is rotated winding wire rope, hook up and down

How to tell mini electric hoist performance

Mini electric  wire rope hoist  products workshop interior often use lifting tools, but also the home of choice for heavy lifting, mini electric hoist, small size, light weight facilitate installation, operation and lifting stability. Users at the time of purchase, according to the following distinguished miniature electric hoist quality and performance.
1, click the up and down keys to observe the running interval, the interval is smaller miniature gourd better.
2, mini electric hoist body shell or high strength die-cast aluminum body stretching.lever hoist Extrusion molding thin-walled precision manufacturing. Have an independent transmission system, sealed inside two coaxial transmission gear mechanism, the use of long-life oil bath lubrication system.
3, miniature gourd with DC electromagnetic disc brake, brake torque, smooth, fast, low noise.
4, mini electric  lift hoist  control after power up and down and move around, observe the arrow keys are accurate, running up and down at the same time pay attention to rest, is there a brake sound, while looking after repose, when there is decline in the chain, if so, that friction plate over loose, or not installed properly.

Explosion-proof chain hoists classification

Explosion-proof electric  lift hoist  lifting equipment is not the only, and explosion-proof chain hoists, the same product in the job it is friction between the impact will not occur mechanical sparks to effectively prevent fire accidents, ensure that the national wealth and personal safety, but also machinery and mechanical maintenance of essential special tools.


Explosion-proof hoist and hoist the main difference is that ordinary proof chain hoists material is aluminum bronze and beryllium as the blank, chain hoists shell is also used in H62 copper alloy materials. Why use this information as proof chain hoists raw materials, mainly bronze alloy, aluminum bronze alloy does not occur when impact or friction sparks, it is very suitable for the manufacture of flammable, explosive, corrosive place under magnetic and safe to use. Mainly alloy containing 30% oxygen or 6.5-10% methane empty oxygen withstand 561LJ impact energy, the impact of 20 magnetic, neither of sparks and burning.
Explosion-proof grade is proof chain block s level is d Ⅱ AT2 to d Ⅱ AT4, d represents flameproof; II on behalf of Class II proof that Plant Explosion. C stands for C-level hazardous areas, that is, for the most dangerous region, T4 temperature class representatives, from T1-T6, T6 is to achieve the highest.
The force of friction parts chain hoists including chain hoists lifting round form, siding, bracelet wheel, hooks, gears, gear shafts are made ​​of aluminum bronze and bronze alloy made ​​of data, proof chain hoists can be widely applied the petroleum, petrochemical, gas stations,hoist and trolley oil depots, gas, chemical, military, power, mining, electronics, railways, and other potential fire and explosion hazard environments.

Four features of frequency electric hoist wire rope

1, can reduce the starting and stopping of the shock: wire rope winch  with a smooth operation frequency performance, which can reduce the start and stop time of the impact, especially for the installation of precision molds, etc. are not allowed vibration in the work environment.
2, can be set according to demand the lifting speed: to pay Lifting speed at 1/10 of the rated speed to be set between the rated speed, in order to select the most suitable operating speed.
3, improve work efficiency: wire rope  lift hoist  inverter under no-load, can hoisting speed at rated speed to 1.5 times the rated speed is set between, improve the operating speed under load, in order to improve work efficiency.
4, can easily set the car speed: the motor can be running through the inverter frequency control, you can easily make the motor run at low speed run, improve the accuracy of positioning operation,hoist equipment jog operation can also be carried out.

Explosion-proof electric hoist electric idea how to deal with

Explosion-proof electric hoist applications rather special, in general, relatively high demand for proof. Explosion-proof electric  lift hoist  proof grade is divided into three and four explosion, the explosion of different products corresponding to different environments.
All electrical components electric motor are mounted in explosion-proof enclosure. Including explosion-proof enclosure consisting of several parts, end caps, bearing cover, shaft, terminal box and cover, terminals, terminal screws, seals, screw terminal sets, compression nut, etc., explosion-proof enclosure fastening bolts connecting the number of non-missing, each bolt with spring washers to prevent self-loosening,wire rope winch otherwise they will lose proof function.
Introduction of cable diameter electric motor with terminal box match the diameter of the inlet ring, good line, pressed by the compression nut seals the cable diameter and the inner ring and the seal between the outer diameter and junction box no gap between the seat bore so as to achieve proof function, brake inlet ring diameter Φ6.
Explosion proof enclosure between the mating surfaces of the joint surface, such as the base and cover of the Mouth of the mating surfaces, axis and the axis of the inner cover mating surface,manual hoist terminal screw threaded sleeve with the mating surfaces, etc., can not be bump-proof combination of surface and rust.

Electric hoist overload limiter works

Electric hoist overload limiter is one of important safety devices, such as weight lifting process over rated, then overload limiter will cut off the electric hoist lifting loop, the electric  chain Block  to stop heavy lifting, so as to protect operating personnel and equipment safety, the following for you to explain the working principle of overload limiter.

Overload limiter balancing hoist pulley mounted on the housing means and between the end plates, end plates electrically with one end of the housing to a positioning spindle and the stopper plate, positioning the spindle head equipped with an eccentric shaft extension bracket, balance one end of the pulley device hanging in the eccentric shaft extension bracket head, the eccentric bottom bracket with dowel pins, eccentric side of the bracket support plate, the upper loading a proximity switch, eccentric bracket overhang bracket with the eccentric shaft center positioning hole centers offset mandrel 3 mm. When lifting heavy overload, the eccentric bracket shell around the  lift hoist  side panel positioning mandrel rotates counterclockwise in to a preset distance proximity switches, proximity switches off the contactor line package lifting circuit, cutting off electric hoist lifting motor power, the electric hoist stops running, play overload limiting role in achieving the safe operation of the crane, improve the reliability and security.
Hoist overload limiter are one and split into two categories, such as the need to replace the overload limiter encounter such situations, to consider the electric hoist load, the case was Joseph wire rope electric hoist rope should also consider factors such as magnification and diameterload chain , to avoid overload limiter after the purchase can not be used without situation.

Diversification of electric hoist operation mode

According lift hoist  structure is divided into fixed and running style, no matter what form will need to run on the beam or crane work, but with the requirement to improve the device's operating environment determines the diversity of electric hoist operating mode , the following Detailed.

Electric  rope hoist  operating mode changes on: trolleys can work in large curvature track, and trolley wheels can be equipped with multi-beam models, such as the most common H-type, U type, etc., all framed car, you can in a single beam run, can also be run on dual-beam track.
Operating agencies parameter changes: lifting height increases, according to the different requirements, up to 120 meters, changing the speed of running and lifting, running speed can also be made ​​into double speed.
Changes in the structure: with multiple roping,chain block you can use the electric hoist lifting hook, the field can be used for high temperature metallurgical hoist, to solve the user due to space constraints and plant design, low headroom hoist and so on.
Hoist motor parameter changes: According to user's requirements, the motor voltage, frequency, series protection and insulation class and other new designs. Such as: voltage 220V415V440V660V, frequency 50HZ, 60HZ; protection class IP54, IP55IP56 etc.; insulation level up to class H.

Wire rope hoist brake selection to local conditions

Wire rope hoist brake is one of the essential parts, according to the wire rope hoist selection and use of environmental products and other practical needs to choose, the following detailed description of your brakes to choose how to do local conditions.

Wire rope chain Block  brakes must first consider the type and standard specifications, such as: lifting mechanism, luffing mechanism must be set to normally closed brake, walking or turning mechanism can be used normally closed brake.
Second, consider the use of premises, such as: Brakes installed there is enough space, the choice of block, arm band brake or disc brake, space is limited value, can be used within the shoe or clamp disc brakes.
Finally consider supporting wire rope lift hoist s used in the environment, there are strict requirements for oil leakage occasion use pneumatic brakes, the ambient temperature can be used insulation demanding high level of electro-hydraulic brakes. For special occasions, should be based on need for additional brake additional features. In the low temperature environment, you can use the electro-hydraulic thrusters of the heater. Conversion process for starting and braking when there are strict requirements, the installation of the brake limit switch for opening and closing state.wire rope winch For maintenance, adjustment difficult implementation environment, the installation of brake clearance balancing device and the friction lining wear compensation device. Additional manual brake device can be opened manually in exceptional circumstances brakes.
Wire rope  lever hoist  are many types of brake parts, the choice of when to use the environment to local conditions and other factors to consider, if you choose incorrectly, can damage the host, re-appeared personal risk and property damage.

Affect the life of lifting belt use and maintenance

    Lifting belt is particularly widely used sling products, materials commonly used polyester filaments, with a wear-resistant,manual hoist anti-UV, anti-oxidation effect. In addition to material on the edge, lifting with the life of the same with our daily use and maintenance is closely related to the following detailed description.
       Use lifting belt overloading can not remember when first used, you can not sling and eye damage and its connected devices, lifting devices should be smooth with no sharp edges. Secondly, do not use the strap to tighten knot or play in the mobile lifting belt and cargo must not drag.load chain Finally, be careful not to be used without jacket lifting belt carrying a sharp corners, edges of heavy loads.
       Lifting with routine maintenance should pay special attention to:
       1, high temperature applications or lifting chemicals circumstances, must comply with the instructions for use or production plant for consultation.
       2, lifting belt in acid-base environment, it should be immediately washed with water.
       3, lifting belt should be stored in dry and ventilated dedicated shelves, light and no UV radiation conditions,lift hoist not on an open flame or flammable materials nearby.

Three rope frayed Analysis

The hoist rope can be said that the most frequently used accessories, but also lifting the most widely used, but when the operation wire in contact with other objects, friction. In the mechanical, physical and chemical action, wire rope wear and other issues will continue to surface, a serious impact on the  lift hoist  and the whole machinery of operation and efficiency, the following is your analysis of the three main situations rope wear:
1, deformation wear
Due to vibration, collision damage caused by the rope hit the surface, called deformation wear, abrasion is a local phenomenon. If the surface of the wire rope drum impact by other objects, wire rope electric hoist lifting wrapped around each other to fight, or due to deflection pulley and roll center phenomena arising bite rope, wire rope will cause deformation wear. This deformation wear and deformation due to local press, the wire cross-section extending to the sides at the extrusion into a fin-shaped.chain block From outward appearances, wire width expansion, although much reduced wire cross-sectional area, but the local press at the steel surface material hardened, easily broken wire.
2, internal wear
In use, the rope pulley rolls or after exposure to the entire load of the pressure in the side of the rope, the plurality of thin wires can not be exactly the same radius of curvature. Same time as the rope bends, wire rope, steel wire inside the root will generate force and produce another slip, then contact stress between stocks and shares increases, the share between adjacent wires produce local indentation furrow. When repeated cycles stretch bending, is generated in the deep recesses of stress concentration was broken, constitute internal wear. Usually thin wire rope surface pressure and the pressure proportional to the tension of the same case, since the pressure receiving area are different, the pressure per unit area is different. Under pressure from the surface wear of view, the use of line contact wire rope advantageous than using point contact, the use of surface contact wire rope line contact than using more favorable. In addition, the degree of bending wire rope, velocity, internal wear on the rope are affected. Obviously, the selection line contact or surface contact type of rope is an effective way to reduce internal wear.
3, the external wear
In the course of wire rope and the pulley groove outer periphery, drum set, a top hook surface wear caused by the contact part of the external wear. The external worn rope diameter becomes thinner,hoist and trolley the outer peripheral surface is polished fine steel.
External wear of the rope to bear the load of the wire cross-sectional area decreases, the rope breaking load is reduced accordingly.
Wear a single week than the whole week wear worse, hook group it should be possible to make a single week of the wire to wear uniform wear all week. Entire length of the wire should be as far as possible uniform wear. Such as cranes wire rope used for the first medium-term, generally extend rope life 30% to 40%.

How to check before installing hoist beam

    Before installing and using electric hoist,hoist equipment the intention is very important job is to check whether the standard I-beam, in order to ensure the normal operation of electric hoist, how to check the work, the following for you to do the following description:
       Electric hoist installation, respond beam track end, straightness and twist to check method is: Level measurement track elevation, level degree, track the location of the top face of the longitudinal inclination of its design should be ≤ 1/1000. Each 2m measuring point, full height difference of not more than 10mm; rail top surface elevation tolerance ± 10mm, the same cross section relative difference in elevation between two parallel tracks should be ≤ 10mm; should be noted that: electric  lift hoist  beam track along the longitudinal direction in the horizontal plane the bend, each measuring 2m length tolerance of ± 1mm;hoist and trolley beam lateral inclination orbit track width should not exceed 1/100; orbital welding electric welding quality should meet the relevant requirements, then the head and sides welds shall be ground smooth.
       Electric hoist can be used alone and also can be used with lifting beam or driving for use.

Upside down electric chain hoist features

Upside down electric  lift hoist  is also called "stage gourd", the name of the field associated with the use of history is nothing, why the inverted chain hoist can be applied to the stage, compared with other chain hoist What characteristics do the following description:
       Upside down electric chain hoist with 110 volt control circuit heat treatment, with screw-type limit switches, stamping steel shell, lightweight and rugged; high-strength safety hook;hoist equipment chain galvanized grease in the gear box fitted to prevent oil droplets penetrate into the arena, hoist motors sealed in aluminum rims cylindrical enclosure permanently protect motors. Upside down electric chain hoist efficient, lightweight motors, non-asbestos brake system, low energy consumption; forming heat treatment of steel chain guide plate; hanging hanging there under the limit switch device,wire rope winch the motor automatically stops to prevent the chain beyond, to ensure safety; suitable for use with various controllers and circuit distributor connected.
        Note: upside down electric chain hoist for temperature -25 degrees to 40 degrees, in the absence of fire, explosion and corrosive media environment, prohibit lifting the molten metal, toxic, flammable and explosive items.

Electric wire rope hoists serialization problem

   For now, the domestic electric  lift hoist  and other lifting industry developed rapidly, especially in the past two years, as China's economic strength gradually improved, driven by the rapid development of the lifting industry, but in comparison with developed countries, too single product variety lack of technological innovation, the specification is not complete.
       CD1 wire rope hoist is that people most frequently used one of the products, but the structural design, speed reducer, safety precautions, electrical control and other areas to consider our electric hoist comparison with the developed countries have yet to progress.load chain Wire rope hoist fewer varieties, specifications missing. Eg: CD1 wire rope electric hoist weighs only 0.5 t, 1t, 2t, 3 t, 5t, 10t these six types, lifting height coverage for the 6-30m, lifting speed :1-5t single speed of 8m / min, 10t single speed 7m/min. Although some domestic manufacturers on the basis of the development of the 10t 16t, 20t, 30t expansion of large-tonnage electric hoist series, but still can not form a more complete and reasonable wire rope hoist  products, and foreign range 0.25-80t lifting capacity and a variety of play l combination of height and lifting speed compared to there is a big gap.

Electric hoist control box work environment requirements

   Electric hoist electric hoist control box is to control the operation of the main control mechanism.hoist and trolley Mainly by the transformer, box, terminals, contactors and other components. Electric hoist control box chain with a machine quality AC contactor, the load and instantaneous overload are much improved, but the working environment of the control box there is a certain requirements before normal use.
       Control box work environment requirements:
1, ambient air temperature: -20 ℃ ~ +40 ℃.
2, the air relative humidity: lowest average humidity of 90%, with an average temperature of 25 ℃, and also taking into account variations due to temperature control box on the lift hoist  Cream.
3, in the workplace should be no violent oh one and vibration.
4, in the absence of an explosion in the use of micro-media, and medium without corrode metal and damage the insulation of gas and dust (including the point of dust).
5, no more than 2500 meters above sea level to use.
       Electric  rope hoist  control box can also be provided upon request multi-core cables of different lengths and flashlight door, opened the lid of the control box, the removable from hinge, user-dark group Aung, maintenance, control box electronics chain has to take and mechanical linkage, so that the same group of two contacts can not be connected to the circuit; each hoist control box is equipped with electrical schematics, wiring terminals are clearly consistent with the schematic diagram number, easy to use almost maintenance, wiring.

Electric hoist way to promote and noise fault solutions

Electric  lift hoist  so that our country in this field and construction mechanization level of civilization has a greatly improved. From the early promotion of do not know, do not understand, do not use to this day in the cities of the construction industry has become an indispensable prerequisite equipment for the industry thought and understanding is a great improvement; domestic hoist manufacturing and leasing industry mushrooming development of the country's manufacturing enterprises no less than dozens of gourd, annual production had over 10,000, in the world, can also be called gourd production big country. Moreover, in the  wire rope hoist  structure, technology, technology has been greatly improved and enhanced. Meanwhile reach cantilever beam structure is the way, the stability of its force far less now widely used zipper-style lightweight and stable. Nevertheless, China's manufacturing industry in the technology gourd, structure, process and even the materials are to improve and enhance the space. Abnormal noise occurs in the control loop, making noises, typically contactor fails to deal with fault contactor maintenance, overhaul can not be replaced, treatment, self-noise elimination.hoist equipment Motor makes any abnormal noise, immediately stop, single-phase operation, the entire issue of regular motor suddenly strong suddenly weak hum; while bearing damage when near the bearing and shaft couplings errors, or when the motor slightly sweep chamber, when not accompanied by shrill voice. In short, the difference should be based on the noise, to find fault, for itemized repair and restore normal performance of the motor when the motor fault untreated,load chain prohibit the use of gourds. First determine reducer gearbox or bearing on whether to raise the oil prior to use, whether to use periodic replacement of oil, but also excessive wear or damage to the gears and bearings.

Master control loop electrical damage to the electric hoist impact

Electric hoist at work will usually be some failures, there will mainly introduce the cause of the malfunction. When the lift hoist  Lord, electrical control circuit is damaged, the line is disconnected or bad, but also make hoist motor phase does not work, this phase is missing, the need to repair the main, the control loop, maintenance, in order to prevent the main, control loop gave power phase three-phase motors and burned the motor. Hoist motor terminal voltage is lower than the rated voltage, motor starting torque is too small, so do not move goods lifting hoists, and unable to work. Abnormal noise occurs in the control loop, making noises, typically contactor fails to deal with fault contactor maintenance, overhaul can not be replaced. Motor makes any abnormal noise, immediately stop and check whether the motor running single phase, or bearing damage, coupling axis errors and "sweep chamber" faults, abnormal noise from the gearbox issue, reducer fails, then should stop examination, first determine the reducer gearbox or bearing on whether to raise the oil prior to use, whether to use periodic oil change. Electric  rope hoist  long-term application, the brake ring wear is too large, the brake spring pressure decreases, the braking force is reduced. Should first check the hoist is overloaded with overloading the motor heat, long-term overload the motor will burn; motor is not overloaded, still hot, you should check whether the motor bearing damage; should also check whether the motor is required duty work, which is caused by the motor heat one of the reasons, should be used in strict accordance with the motor duty work. Weight rose to the air, check the system voltage is too low or fluctuating too large, this kind of situation is generally contactor contact welding, when you press the stop switch when the contactor contacts can not be disconnected, the motor was as usual power operation,  hoist equipment  without stopping; into extreme positions such as limit malfunction, Hulu does not stop. This happens, immediately cut off the power, the gourd forcibly stop. Winter construction, the circuit still can not start the motor without failure, the reason is the brake ring freezing.

Chain hoists different in different geographical appellation

There is a simple to use, easy to carry the manual lifting is called chain hoists,  chain Block  with the widespread use of different geographical rivals pull hoist is called also different. Chain hoists in the northeast of China referred to as "burden does not fall" in the Hebei region referred to as "chain hoist" or "down chain" in the Shanghai region it is addressed as "gods gourd", due to geographical and cultural differences around the so called France is also different, leading some people will not misunderstand that hoists.
manual hoists hands by pulling the chain, bracelet wheel rotation, the friction plate ratchet, brake pressure into one common rotation axis will rotate sprocket teeth, tooth stub shaft and spline hole gears. Thus, the device is splined sprocket holes on the lifting gear driven lifting chains, heavy lifting so smoothly. Using one-way ratchet friction disc brakes, the braking load on their own, under the action of the spring pawl and ratchet gear.
Chain hoists specifications from the smallest can reach 100 tons 0.25 tons of large tonnage specification chain  lift hoist  , chain hoists, including imports and domestic chain hoists chain hoists are two chain hoists, there are many brands: Elephant Chain gourd, TOTO chain hoists, chain hoists day Chile, Germany Yale chain hoists.
Chain hoists are widely used in factories, miners, docks, warehouses, construction sites, agricultural production and other fields, and lifting equipment for lifting goods. And supporting the use of a variety of manual monorail composed manual lifting and transport trolley for overhead monorail transport, manual single girder overhead cranes and jib crane.

On the lifting industry chain hoists

manual hoist is a simple to use, easy to carry the manual lifting, also known as "chain hoist" or "down chain." Chain hoists for small equipment and cargo lifting a short distance, the weight is generally not more than 10t. Chain hoists with a compact, hand-pull small features.
Chain hoists lifting gear structural principle: with reverse backstop brake reducer and chain pulley combination.
Chain hoists hands by pulling the chain, bracelet wheel rotation, the friction plate ratchet, brake pressure into one common rotation axis will rotate five tooth sprocket, four minor tooth gear and spline hole. Thus, the device is splined sprocket holes on the lifting gear driven lifting chains, heavy lifting so smoothly. chain Block  with one-way ratchet friction disc brakes, the braking load on their own, under the action of the spring pawl and ratchet engagement to ensure the safety brake. Chain hoists with safe, reliable, easy maintenance, high mechanical efficiency, bracelets pull small, light weight and portability, smaller size and beautiful appearance, durable, suitable for factories, mines, construction sites, wharves, docks, warehouses, etc. for installation of equipment, lifting goods, especially for open and no power supply, as well as flammable and explosive places more of its important role.
Major parts chain hoists used steel materials,lift hoist chain lifting chain with 800Mpa high strength, high strength material foot hook, chain heat, low wear, corrosion of the chain; calcined playing style hook design ensures a slow start l prevent overload; meet European CE safety standards.

Engineering machinery and the development of multi-purpose mini larger space

  With vigorously promote western development, China's large-scale infrastructure construction has entered a crucial stage,chain block led the construction machinery industry, the market for infrastructure to promote the kind of greatly increased demand for construction machinery. China will be a long period of time to maintain the strong market demand for construction machinery, the face of this broad market space, the construction machinery industry with products of large, high-end into the mainstream of development of China's construction machinery.
    Based on our existing level of infrastructure, massive rail, road, port and airport construction boom is expected to continue for at least 10 years or so. During this time, high-end large-scale construction machinery demand will be the mainstream. Chinese enterprises in the field of large-scale high-end engineering machinery share is very low,rope hoist which also means a larger growth potential and space.
    Versatile, miniaturized construction machinery products will also have a larger market space. When large-scale infrastructure construction period, multi-purpose, construction machinery products miniaturization will become mainstream. Such as electric hoist chain  lift hoist ,  on the one hand, multi-purpose versatility is reflected in the improvement of mechanical work, which enables users without increasing the investment under the full effectiveness of the device itself, thus completing more work; the other hand, in order to maximize the use of machinery instead of human labor, and improve the professional production efficiency, adapt to different workplaces and to increase the docks, warehouses, accommodation, building layers and underground engineering applicability of operating environment, a variety of small micro-mechanical will have a broad market space. In this regard, can be completely specialized construction machinery enterprises, will obviously have a more long-term, more potential investment opportunities.

Distinguish the quality of electric chain hoist observe the arrow keys, etc.

We certainly do not remember how electric chain  lift hoist  should be installed today will tell you how to install the electric chain hoist, so that we can be more understanding of the electric chain hoist, also at the time of purchase to know its structure, so as to better law and order to its quality.

Electric chain hoist is often used inside the workshop lifting tool, this small volume, light weight, easy installation, operation and lifting hoists are very stable, has begun to replace bulky electric hoist, electric and CD Hulu will slowly be replaced. In the purchase of electric chain hoist before.

Can be distinguished according to the following quality electric chain hoist, first after power control electric  wire rope hoist  to move around and observe the arrow keys are correct, while paying attention to running up and down stops, if there is the sound of brakes, another stop watching after the chain have declined, and if so, that friction plate too loose, or not installed properly. After these there is no problem, click the up and down keys, observing run distance, the smaller the distance the chain hoist as possible. Use Tips: In some factories or workshops, sometimes you need to run relatively small distances, such as installation or butt,wire rope winch you need to hoist slowly raised or lowered to facilitate calibration and installation, but single-speed electric chain hoist majority, two-speed sometimes slow speed of installation can not meet, this time you can press the button a little way, that tap stopped, time is very short, so that relatively small range of movement can be calibrated after every click once, and so on, will equipment installation was successful. This is why the choice of electric chain hoist when lifting point distance by checking the reason, in principle, the landing distance as small as possible.