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To ensure the safe and normal operation of the electric hoist gantry crane and to extend the lifespan of its components, parts, and the crane itself, regular inspection and maintenance are essential. This article provides a detailed explanation of how often each part of the crane should be inspected and maintained, and the specific steps involved in these processes. We hope this guide proves helpful to you.
During operation, the operator should constantly observe for any of the following abnormal conditions. If detected, stop operation immediately and notify maintenance personnel. Resume operation only after the issue is resolved.
After finishing the work, the operator must perform routine safety inspections and inform the next shift operator verbally or in writing of any problems. If repairs are needed, the next shift operator should inform maintenance personnel. Resume operation only after repairs are completed.
Artikel | Frequency | Content and Requirements |
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Machine noise test | Once every 3 months | Use a sound level meter (decibel meter) to measure noise during lifting, lowering, and traveling. The sound level meter acts like a stethoscope to detect and analyze abnormal conditions through noise levels. |
Inspection with full load | Once every 3 months | Visually inspect for abnormal vibration of the main beam or load during full-load lifting; listen for unusual sounds from mechanisms; when possible, touch gearboxes and motors to detect overheating. Analyze and eliminate any abnormalities. |
Check when full down with full load | Once every 3 months | During full-load lowering, stop the hoist and observe the amount of slip. If excessive, adjust the brake gap of the hoisting mechanism until proper braking is restored. |
Hoist trolley traveling check | Once a week | Observe whether the trolley struggles when climbing, slips, has suspended wheels, rail biting, or flange climbing. If such issues occur, check the main beam stiffness, rail surface cleanliness, and trolley assembly precision. |
Crane brake check | Once a week | Check if there is noticeable asynchrony during running and braking. If so, adjust the gap of the main trolley brake. Preferably, the same person should adjust both brakes to ensure consistent hand feel. |
Crane running condition check | Once a week | During operation, check for abnormal snake-like movement, twisting, lateral slipping, skewing, rail biting, or unusual noises. Record findings and investigate the cause. |
Check the brake in the crane operation | Once every 3 months | Check whether the traveling brake is sensitive and whether it fails to stop the crane or has excessive sliding distance. |
Wheel load balance (three-Leg phenomenon) check | Once every 3 months | Observe whether any of the crane’s four wheels are suspended, or if any wheel shows partial rotation or no rotation during operation, indicating a “three-leg” phenomenon. |
Leakage check | Once every 3 months | Check for oil seepage or leakage in the hoisting reducer and trolley/traveling reducers. |
Surface appearance & quality check | Once every 6 months | Inspect for rust, paint peeling, or physical damage on any part of the crane surface. |
Artikel | Frequency | Content and requirements |
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Running range inspection | Once a week | Check for any obstacles within the travelling range. Ensure the gap between the crane and the top and sides of the construction building is not too small. Also, check for any dangers that may cause collisions with lamps, tubes in the building, or proximity to bare copper conductors. |
End stopper inspection | Once for three months | Check if the end stoppers are deformed, damaged, or at risk of detachment. If fixed by bolts, check for looseness; if welded, inspect weld seams for cracks. |
Rail deformation inspection | Once for half a year | Inspect the rail from both vertical and horizontal directions for abnormal bending or deformation beyond installation tolerance limits. |
Rail installation inspection | Once for half a year | Check for deformation at rail joints, loosened fixing bolts, lateral rail displacement, and weld cracks. Also check for looseness in shim plates and connecting plates. |
Rail wear inspection | Once for half a year | Inspect the rail tread and side surfaces for excessive local wear. For I-beam rails, check the flange tread and ends for peeling, wear, or deformation. |
Artikel | Frequency | Content and requirements |
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Main and end beam weld inspection | Once for half a year | Check whether there are cracks in the welds on the main beam and end beams. |
Main beam wear and deformation inspection | Once for half a year | Check the I-beam flange tread and side areas of the main beam for severe wear or plastic deformation (flange sagging). |
Main and end beam connection inspection | Once for half a year | If the main and end beams are bolted together, check whether the bolts are loose. |
Rail on main beam inspection | Once for half a year | For supported-type rails installed on the main beam, check for abnormal bending or deformation. Check if rail clamps and bolts are loose, and inspect welds for cracks. |
Trolley end stop inspection on main beam | Once for three months | Check whether the trolley end stops on the main beam are deformed, damaged, or at risk of falling off. Check if bolts are loose and welds are cracked. |
Buffer inspection on main and end beams | Once for half a year | Impact buffers installed on the main beam end stops and end beam ends must be securely fastened. Check for loosened bolts and any cracks, fractures, or damage on the buffers. |
Artikel | Frequency | Content and requirements |
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Motor overheating inspection | Once for three months | Check whether the hoisting and traveling motors are overheating. If so, analyze whether the cause is excessive overload, voltage fluctuation, frequent start-stop operations, too small brake clearance, or abnormal friction between the brake wheel and the brake ring. |
Motor abnormality inspection | Once for three months | Check whether the hoisting and traveling motors are difficult to start, excessively noisy, or producing abnormal sounds. Analyze whether the causes include excessive overload, low power supply voltage, incomplete brake release, or poor/loose wiring connections. |
Artikel | Frequency | Content and requirements |
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Wear condition inspection | Once for half a year | For conical brake motors, open the motor cover to observe the wear condition of the conical brake ring or flat brake ring. Manually push the fan wheel axially to check end play; excessive end play indicates severe wear. The end play must not exceed 4 mm and should be adjusted to 1.5 mm. Otherwise, the brake ring must be scrapped and replaced. For flat or shoe-type brake materials, replace them when the wear reaches 50% of the original thickness. |
Brake performance inspection | Once for half a year | Check whether the brake in the hoisting mechanism can effectively stop the load during lowering. If there is excessive slippage, adjust the brake performance promptly. |
Abnormality inspection | Once for half a year | Check whether the locking nuts of each brake (for conical brakes) are loose. Inspect the wear of joints in the linkage mechanism of electromagnetic shoe brakes and check if the spring is loose. If there is a screeching noise during braking, inspect for relative friction or poor contact between the brake wheel and the brake ring (pad or block), and check if the spring is plastically deformed. |
Artikel | Frequency | Content and requirements |
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Gear transmission noise inspection | Once for half a year | Check whether the transmission gears in each mechanism produce abnormal noise. Determine if the abnormal sound is caused by insufficient lubrication, severe gear or bearing wear, gear surface damage, or poor gear machining and assembly accuracy. |
Abnormality inspection | Once for half a year | Check whether the connecting or fixing bolts of each reducer are loose and whether there is any oil leakage. For the hoisting reducer, inspect if the housing has been cracked due to hook swing impact, possibly caused by failure of the hoisting limiter. |
Artikel | Frequency | Content and requirements |
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Wear condition inspection | Once for half a year | Check the wear condition of the rope grooves on the drum. Look for any abnormal wear. |
Drum shell inspection | Once for half a year | Check whether the drum shell has any dents or damage, especially those caused by the hook pulley striking the shell when the hoisting limiter fails. |
Rope guide inspection | Once for half a year | Check whether the rope guide is cracked, and ensure the wire rope can pass smoothly through the rope guide outlet during empty hook lowering. |
Abnormality inspection | Once for half a year | Check whether the rope pressing plate on the drum is loose, whether the drum connection bolts or rope guide mounting bolts are loose, and whether the guide slider inside the rope guide moves smoothly. |
Artikel | Frequency | Content and requirements |
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Broken wire inspection | Once a week | Observe whether there are broken wires on the rope. If the number of broken wires within one lay length exceeds 10% of the total wires, the rope must be scrapped. |
Wear condition inspection | Once a week | The reduction in rope diameter due to wear must not exceed 7% of the nominal diameter. Otherwise, the rope must be scrapped. |
Deformation inspection | Once a week | Ropes that are crushed or twisted due to oblique lifting must be scrapped. |
Corrosion inspection | Once a week | The surface of the wire rope must be free of corrosion and should retain a proper amount of lubricant, without excessive dirt. |
Twist in the air fault inspection | Once for three months | Observe whether the wire rope is twisted due to failure to loosen the rope when binding, which may cause internal stress or misalignment. |
Abnormality inspection | Once a week | Frequently inspect critical working and safety-related areas of the wire rope. Ensure that all rope fixing points are secure. Check for sufficient lubrication and that there is no rope biting at the contact points with pulleys or sheaves. |
Artikel | Frequency | Content and requirements |
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Crack inspection | Once a week | There should be no harmful cracks on the hook, block, or block shell. |
Wear condition inspection | Once a week | There must be no abnormal wear on the hook opening or pulley grooves. |
Abnormality inspection | Once a week | Check for pulley damage, unsecured hook nut, loose bolts on the shell, baffle plate, or baffle shaft plate, and loose bolts on the balance pulley. |
Deformation inspection | Once a week | The hook opening must not show any abnormal deformation. |
Rotation inspection | Once for half a year | Check whether the hook and pulleys can rotate freely and smoothly. |
Artikel | Frequency | Content and requirements |
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Wear inspection | Once for half a year | The tread and the inner surface of the wheel flange must not show any abnormal wear. |
Crack inspection | Once for half a year | The wheel surface must be free from abnormal cracks and damage. |
Artikel | Frequency | Content and requirements |
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Deformation inspection | Once for half a year | Check if the drive shaft has deformation, vibration, or other abnormal phenomena. |
Support inspection | Once for half a year | Check whether the drive shaft support bolts are loose and the oil supply condition. |
Coupling operation inspection | Once for half a year | Check the wear status, fastening condition, and operational state of the coupling for abnormalities. |
Artikel | Frequency | Content and requirements |
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Fixed condition inspection | Once for half a year | Check if the cab’s fixing bolts are loose; if welded, check for cracks in weld seams. |
Working condition inspection | Once for half a year | Verify ventilation, heating, lighting are normal and reasonable; check if the cab shakes excessively. |
Artikel | Frequency | Content and requirements |
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Check visibility | Once for half a year | Check whether the location of tonnage plate is reasonable and obvious. |
Check fixed condition | Once for half a year | Check whether bolts or rivets of tonnage plate and nameplate are loose. |
Artikel | Frequency | Content and requirements |
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Bare slide-wire safety inspection | Once for three months | Check whether the safety distance between crane bare slide wire and surrounding equipment meets regulations and whether appropriate safety protection measures are in place. |
Surface of slide-wire inspection | Once for three months | Inspect the sliding contact surface of the slide wire for corrosion or rust defects; use wire brush or sandpaper to clean timely to ensure conductivity. |
Insulation device | Once for three months | No damage allowed on supporting insulators of slide wire; connection parts should not be loose. |
Cable introducing device inspection | Once for three months | Check wear and tightness of strained steel wire rope supporting the cable when cable introducing device is used. |
Slide wire safety mark inspection | Once for half a year | Check whether there is a safety mark on the non-conductor side connection surface of slide-wire and whether there is an indicator light showing power status. |
Artikel | Frequency | Content and requirements |
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Inspection of wear condition | Once for half a year | Check wear condition of current collector pulley, pin shaft, or suspension ring; no abnormal wear allowed. |
Fixed condition inspection | Once for half a year | Connection bolts between current collector and cable must not be loose; insulators and fixing must be safe and reliable. |
Block turning state inspection of current collector | Once for three months | Current collector pulley should rotate flexibly and smoothly; if there is friction noise or difficulty in rotation, lubricate promptly. |
Spring of current collector inspection | Once for half a year | Springs of current collector should maintain good elasticity without rust or fatigue. |
Artikel | Frequency | Content and requirements |
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Wiring surface inspection | Once for three months | Wiring from current collector to motor and electrical devices (internal wiring), including rubber soft cables, must have no external damage. |
Fixed connection inspection | Once for half a year | All electrical fixing bolts and internal wiring fixing bolts must not be loose; wiring conduits must be firmly fixed to the machine body. |
Flat cable extension performance inspection | Once for half a year | Check whether flat cable has difficulty extending or retracting due to material or aging; flexibility must not deteriorate. |
Cable remove inspection | Once for three months | Check whether the soft cable used as power input has abnormal bending or twisting during movement. |
Artikel | Frequency | Content and requirements |
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Contact and core inspection | Once for three months | Open electromagnetic switch box; check contacts and core for abnormal wear or damage; core end face should be flat and clean. |
Wiring fixed state inspection | Once for half a year | Check whether each wiring fixing bolt is loose. |
Contactor operation inspection | Once a week | Operation should be sensitive and reliable; contacts must be tight without sticking or jamming faults. |
Artikel | Frequency | Content and Requirements |
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Appearance Inspection | Once a week | Button mark should be obvious and there should be no damage to the pendant switch. |
Troubles Abnormity Inspection | Once a week | Connection part between pendant control and end of cable should not have damage and there should not have trouble like broken wire. |
Artikel | Frequency | Content and Requirements |
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Action inspection | Once a week | Check whether the hoist limit switch action is sensitive, safe, and reliable. |
Contact point inspection | Once for three months | Check whether the switch contacts are damaged or broken; replace promptly if severely damaged or worn for safety. |
Wiring fixed state inspection | Once for half a year | Check whether the wiring fixed joint bolts have loosened. |
Spacing position inspection | Once a week | When the hook pulley block is hoisted to the upper limit position, the hoist limit switch should act immediately; the distance between the highest point of the hook pulley block and the lowest point of the drum should be at least 150mm. |
Artikel | Standard |
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Rail tread cleanliness | No attached greasy dirt or amount of dirt. |
Rail span inspection | Bearing type rail: S ≤ 10m, ΔS = ±3mm S > 10m, ΔS = ±[3 + 0.25 × (S-10)] mm Suspension type rail: ΔS = ±5mm Notera: S = span (m), ΔS = tolerance of span. |
Inclination of rail tread | ≤ I/1000. |
Elevation difference of two rails in same section | ≤ s/1000. |
Elevation difference of same side rail bearing | ≤ L/1000. |
Rail joint distance | Joint distance ≤ 2mm. |
Crack and deformation inspection | Cracks and plastic deformation are not allowed. |
Rail juncture displacement | Vertical and lateral offset ≤ 1mm. |
Rail tread fatigue inspection | No spalling or fatigue damage on rail tread. |
Wear and tear of rail | Support type rail: wear ≤ 10% of original size Suspension type rail: tread wear ≤ 10%, width wear ≤ 5%. |
Fixed installation inspection | Joint bolts must be tight; welding lines must have no cracks or defects. |
Artikel | Standard |
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Appearance quality of main beam inspection | Damage or unusual deformation is not allowed, the corrosion proportions should be not more than 10% of original dimension, coat of paint should not flake. |
Welding line quality inspection | Defects like crackles in welding line are forbidden. |
Camber inspection at midspan of main girder | Camber △F=(1/1000~1.4/1000)s. |
Bending of main beam inspection | Bending △Fp≤s/2000. |
Worn condition inspection of electric hoist traveling rail | For main girder I-beam type rails, tread wear should not exceed 10% of the original size; width wear should not exceed 5% of the original size. |
Deformation of I-beam flange | Flange of I-beam should not have obvious plastic deformation. |
Running rail fixed installation inspection | The rails are connected by bolts, which should not be loose, fixed rail through welding, welding seam should not have crackles. |
Artikel | Standard |
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Appearance quality of end beam inspection | Damage or unusual deformation is not allowed, the corrosion proportions should be not more than 10% of original dimension, coat of paint should not flake. |
The deviation degree of wheel distance | K≤3m, △K=±3mm K>3m, △K=±K/1000mm (K: base distance, △K: deflection of base distance). |
Artikel | Standard |
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Traveling motor inspection | The motor should not have difficult starting, excessive noise, abnormal sounds, or overheating. |
Traveling brake inspection | Brake should be safe, reliable and flexible. When the following conditions occur in the brake parts, they should be scrapped: Wear of crackles, brake ring or brake block reach 50% of original thickness. Spring deformation. Wear of small shaft or diameter of axle hole reach 5% of original diameter. Brake friction surface of brake wheel should not have faults or oil stains. When wear of brake wheel flange thickness reaches 50% of original thickness, and flange roughness reach 1.5 mm, they should be scrapped. |
Installation of traveling reducer | Fixed connection bolts must not be loose. |
Appearance of traveling reducer | The shell must not be traumatized or damaged. |
Gear quality inspection | The gear should be scrapped under any of the following conditions: Cracks on the gear. Broken teeth. Pitting damage on the tooth surface reaches 50% of the meshing surface or the depth reaches 15% of the original tooth thickness. Other meshing tooth thickness wear reaches 25% of the original tooth thickness, or 30% for open gears. |
Traveling reducer sealing inspection | No leakage. |
Key connection inspection | The key cannot be loose or deformed. |
Worn condition of shaft | Diameter difference of wheel tread is no more than 2%. |
Bearing inspection | Check whether there is grease; there should be no damage or crack. |
Oil seal inspection | There shall be no aging. |
Gear coupling inspection | Reject when any of the following has occurred: Crackles. Broken gear teeth. The worn of rim thickness amounts to 20% of original thickness. |
Surface of wheel quality inspection | Reject when any of the following has occurred: Crackles. The worn wheel rim thickness amounts to 50% of the original thickness. Deflection of flange thickness reaches 20% of original thickness. Wheel tread thickness proportion amounts to 15% of original thickness. When traveling speed ≤ 50 m/min, roundness reaches 1 mm. When traveling speed > 50 m/min, roundness reaches 0.5 mm. |
Difference of both sides wheels diameters | Diameter difference of wheel tread ≤ 1%. |
Worn condition of wheel shaft | The worn proportion should be less than 2% of the original shaft journal. |
Bearing inspection | There should be no damage or crack. |
Artikel | Standard |
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Deviation degree of span(△S) | S≤10m, △S=±2mm. S>10m, △S=±[2+0.1(S-10)]mm. △Smax=10mm. |
Diagonal difference of loading bridge | K≤3m, |S1-S2|≤5mm. K>3m, |S1-S2|≤6m. |
Height different of wheel forced on(△h) | S≤10m, △h=±2.5mm, 10<S≤15m △h=±3.5mm, 15<S≤20m △h=±4.5mm, 20<S≤25m △h=±5.5mm, 25<S≤30m △h=±6.5mm, 30<S≤35m △h=±7.5mm. |
Artikel | Standard |
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The rising temperature of motor inspection | The rising temperature for E grade insulation motor should be no more than 115℃. The rising temperature for F grade insulation motor should be no more than 155℃. |
Abnormity inspection of motor | Check whether the motor starts grudgingly or whether there is abnormal sound. |
Artikel | Standard |
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Brake performance inspection | Brake performance should be safe and reliable and act flexibly. |
Brake parts quality inspection | Reject when any of the following has occurred: CracklesWorn proportion of brake ring amounts to 50% of original thickness.The spring has plastic deformation. Worn proportions of axis hole diameter amounts to 5% of original diameter. |
Brake wheel quality inspection | Brake friction surface of brake wheel should not have the faults or oil stains.Reject when any of the following has occurred: CracklesThe brake ring worn thickness is 40% of original thickness, wear of the running brake wheel reach 50% of original thickness. |
Artikel | Standard |
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Installation state inspection | Joint bolt should not be loose. |
Gear quality inspection | Reject when any of the following has occurred: Crackles. The gear teeth have broken. The corrosive-pitting surface amount to 50% of the mating surface and the depth amounts to 10% of the origin. The permitted worn proportion of first-level gear amounts to 10% of the origin, and others amounts to 20%, traveling gear amounts to 25%. The exposed gear amounts to 30%. |
Reducer appearance inspection | No defect like damage. |
Sealing quality inspection | No leakage. |
Anomaly inspection | Abnormal sound and abnormal heating are forbidden. |
Inspection of other reducer parts | Any loosening, distortion or unusual wear are all banned to the connection between key and key slot. The worn proportion of gear shaft should be less than 1% the original shaft journal. The worn proportion of other shafts should be less than 2% the original shaft neck. Aging and metamorphosis are forbidden. Seamless on the matching surfaces are forbidden. |
Artikel | Standard |
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Fixed condition at the end of steel wire rope inspection | Pressing plate at the end of steel wire rope should not be loosened. |
Rope guider working state inspection | The steel wire rope should successfully be let out from rope guide when empty hook is descending. |
Drum inspection | Reject when any of the following has occurred: Crackles. Worn proportion of drum wall amounts to 20% of the original thickness. |
Artikel | Standard |
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Pulley groove appearance inspection | Block groove should be smooth and there should be no limitation. |
Block rejection standards | Reject when any of the following has occurred: Crackles. Uneven wear of block groove amounts to 3mm. Wear of groove wall amounts to 20% of the origin. The worn of the bottom of block groove proportion amounts to 50% of the wire rope diameter. Any defects damage the wire rope. |
Artikel | Standard |
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Wire rope quality inspection | wire scrap specific requirements can reference ISO 4309-2017. |
Artikel | Standard |
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Hook quality inspection | Reject when any of the following has occurred: Crackles. Wear and tear of dangerous section is more than 10% of original dimension. Open degree is more than 15% of the original dimension. Twisted deformation is more than 10% the original dimension. Dangerous section or neck of hook occurs plastic deformation. |
Artikel | Standard |
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Wheel quality inspection | Reject when any of the following has occurred: Crackles The worn wheel rim thickness should be no greater than 50% the original thickness. The worn width proportions should be greater than 5% of max diameter of original wheel. |
Clearance limit between wheel rim and rim of I-steel | Max. Clearance should be not more than 50% of the wheel tread width. |
Artikel | Standard |
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Bare feed slide wire security check | Same to monthly inspection. |
Sliding surface inspection | Same to monthly inspection. |
Insulation device inspection | Same to monthly inspection. |
Flexible cable entry device | Same to monthly inspection. |
Safety sign of slide line inspection | Same to monthly inspection. |
Artikel | Standard |
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Wear and tear state | Same to monthly inspection. |
Steady state | Same to monthly inspection. |
Rotation condition of collector pulley | Same to monthly inspection. |
Collector spring in spection | Same to monthly inspection. |
Artikel | Standard |
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Wiring appearance inspection | Same to monthly inspection. |
Steady condition | Same to monthly inspection. |
Flexible movement inspection | Same to monthly inspection. |
Stretch performance of flat cable inspection | Same to monthly inspection. |
Artikel | Standard |
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Contact point and iron core inspection | Same to monthly inspection. |
Wiring fixed state | Same to monthly inspection. |
Contactor inspection | Same to monthly inspection. |
Artikel | Standard |
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Appearance inspection | Same to monthly inspection. |
Abnormal failure inspection | Same to monthly inspection. |
Artikel | Standard |
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Action inspection | Same to monthly inspection. |
Electric shock inspection | Same to monthly inspection. |
Wiring fixed state | Same to monthly inspection. |
Limit location inspection | Same to monthly inspection. |
Artikel | Standard |
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No-load test running | Operate the crane to move forward and backward, the trolley to move left and right, and the hoist to lift and lower. Check for any abnormalities and ensure that the operations match the button labels |
Safety device check | Check the lifting limit switch, travel limit switch, and other safety devices to ensure their actions are sensitive, safe, and reliable. |
Artikel | Standard |
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Rated load test | The vertical deflection of the main beam must not exceed the specified values in the safety standards for various types of cranes with hoist. |
Overload test | When lifting 125% of the rated load, the main beam must not show any signs of permanent deformation, cracks, paint peeling, loosening, or damage after unloading. |
Dynamiskt belastningstest | Lift 1.1 times the rated load at mid-span and perform only hoisting, lowering, and crane travel operations. Within the specified time, all mechanisms should operate smoothly, flexibly, and reliably without any abnormalities. |
All moving parts of the crane that require lubrication must be lubricated regularly. The lubrication system should be inspected to ensure that the lubricant is being delivered smoothly. The lubrication points, frequency, and type of lubricant used should follow the manufacturer’s recommendations. Lubricant should only be applied when the crane is stationary.