목차
Like all mechanical equipment, wire rope hoists are subject to wear, and tear, and occasional breakdowns. Recognizing the early signs of trouble and knowing how to address them can mean the difference between making minor adjustments facing costly and time-consuming repairs, or worse, a complete operational shutdown.
The importance of electric wire rope hoist maintenance and inspection cannot be overstated. It not only ensures the longevity and optimal performance of the hoist but also guarantees the safety of operators and the workplace. This article aims to equip wire rope hoist users with the knowledge needed for wire rope hoist maintenance and inspection.
Preventive wire rope hoist maintenance is the cornerstone of ensuring the longevity and reliability of wire rope hoists. This proactive approach involves regular inspections, lubrication, timely repairs, and adherence to a wire rope hoist maintenance plan tailored to the hoist’s operational requirements and environmental conditions. It aims to prevent common issues like wire rope wear, misalignment, and mechanical failures. Proper upkeep can identify signs of wear or damage in advance, allowing for timely repairs and significantly reducing the likelihood of unexpected breakdowns and costly downtime. Here are key strategies for implementing a robust preventive wire rope hoist maintenance program.
Operators should perform a visual wire rope hoist inspection daily to check for any signs of wear or damage on the wire rope, hook, and other visible components. Ensure that all controls are functioning properly and that the hoist operates smoothly without any unusual noises.
Inspection Items | Requirements |
Work Location | Ensure there are no obstacles within the operator’s walking area. |
Running Tracks | From the ground, observe that there are no abnormalities on the tracks. |
Button Controls | The lifting, lowering, and lateral movements should be responsive and accurate. Pressing a group of buttons simultaneously should not cause the hoist to operate. |
리미트 스위치 | When the hook is unloaded and reaches the limit position, the limit switch should be accurate and reliable. |
Hook Assembly | The hook should rotate freely within a 360° horizontal and 180° vertical range. Ensure that the pulley rotates smoothly without jamming or rubbing, the hook nut has no abnormality, and the groove lock device functions properly. |
Wire Rope | Inspect visible sections of the wire rope daily for any signs of damage or deformation. Pay special attention to the points where the wire rope is secured on the machinery. Report any noticeable changes to a supervisor, who should inspect according to ISO4309:2017, section 5.2. |
브레이크 | The brakes for lifting, lowering, and operation should be responsive and reliable. |
Guide Rollers and Other Safety Devices | Ensure that they operate normally and are safe and reliable. |
Schedule comprehensive wire rope hoist inspections at intervals recommended by the manufacturer, typically every six months or annually. These wire rope hoist inspections should be conducted by trained personnel who can identify signs of wear, corrosion, or damage to mechanical and electrical components.
The frequency of monthly wire rope hoist inspections is determined based on the importance of each component for safe operation, the frequency of use, and whether the part is considered to be prone to wear. Generally, inspections are categorized into three levels:
The wire rope hoist inspection items, requirements, and levels are outlined in the table below:
Inspection Items | Requirement | Level | |
---|---|---|---|
Running Tracks (I-Beam) | Obstacles within Running Range | The minimum distance from buildings and other equipment should be no less than 100mm. | I |
Track End Stops and Connection Bolts or Welds | No deformation or damage; bolts should not be loose; welds should be free of cracks. | I | |
Connection Bolts for Fixed Tracks | Bolts should not be loose. | III | |
Track Joint Welds | Welds should be free of cracks or defects. | III | |
Track Wear | No abnormal deformation or wear at the contact points with wheels. | III | |
Hook Assembly | Pulleys | Pulley grooves should not have abnormal wear; rims should be intact and undamaged. | I |
Appearance | Pulley covers should not be damaged; shaft covers and pins should not be loose; hook locking device should operate normally. | I | |
Working Condition | Pulley rotation should be smooth and flexible. | III | |
Balance Pulley | Appearance | The pulley should be undamaged and connections should be secure. | III |
Wall Plates | Bolts should not be loose. | III | |
Wheels | Tread and rims should not have abnormal wear or damage. | III | |
Wire Rope | End Fixation | Wire rope ends should be securely fixed and free from abnormalities. | I |
Appearance | No kinks, burns, significant looseness, or corrosion; rope should be lubricated. | I | |
Safety Standards (Discard Criteria) | Follow ISO4309:2017 section 6. | I | |
Gears | Lubrication | Open gears should be regularly greased; enclosed gears should be regularly oiled. | II |
케이블 | Appearance | Cables should be free of external damage, abnormal bending or twisting, and aging. | II |
Assembly Condition | Connections to switches should be secure; central ring should not be detached from the slide; support wires at both ends should not be loose. | III | |
Collector | Working Condition | Collector rollers should rotate smoothly and without noticeable wear. | II |
Appearance | Connection bolts should not be loose; insulators should not be loose or damaged; springs should not have lost their elasticity. | III |
Electric hoists that are in normal operation should undergo a comprehensive safety inspection once a year. The items and requirements for the annual wire rope hoist inspection are outlined in the table below:
Inspection Items | Requirement | |
---|---|---|
Tracks (I-Beam) | Surface Cleanliness | No oil stains or excessive dust. |
Inclination | Should not exceed 1/1000. | |
Joints | No cracks in welds or tracks; vertical and horizontal offsets should not exceed 1mm. | |
Wear Condition | Wear on the surface should not exceed 10% of the original size; width wear should not exceed 5% of the original size. | |
Wheels | Rim | Wear on the rim thickness should not exceed 50% of the original thickness; the lateral total gap between the rim and track should be less than 50% of the wheel tread width. |
Tread | Wear on the tread diameter should be less than 5% of the original size; diameter difference should be less than 1% of the nominal diameter; roundness difference should be less than 0.8mm. | |
Appearance | No cracks or damage. | |
브레이크 | Repeat checks as per monthly inspection requirements. | |
Wire Rope | Repeat checks as per monthly inspection requirements. | |
Gears | Lifting Mechanism Gears | Wear on the first-stage gear should be less than 10% of the original tooth thickness; other gears should be less than 20%. |
Running Mechanism Gears | Wear on the first-stage gear should be less than 15% of the original tooth thickness; other gears should be less than 25%; open gears should be less than 30%. | |
Tooth Surface Defects | No cracks or broken teeth; pitting damage should not exceed 30% of the mating surface, and depth should not exceed 10% of the original tooth thickness. | |
훅 | Appearance | Surface should be free of cracks; no plastic deformation at threaded parts, danger sections, or neck; defects should not be repaired by welding. |
Danger Section Wear | Wear should not exceed 5% of the original size. | |
Opening Degree | Should not exceed 10% of the original size. | |
Twisting Deformation | Should not exceed 10. | |
Pulleys | Uneven wear should be less than 3mm; wall thickness wear should be less than 20% of the original wall thickness; bottom wear should be less than 25% of the wire rope diameter; no other defects that damage the wire rope. | |
Shafts | Gear Shaft Wear | Wear should not exceed 1% of the original shaft diameter. |
Other Shafts | Wear should not exceed 2% of the original shaft diameter. | |
북 | No cracks; wall thickness wear should be less than 10% of the original wall thickness. | |
Keys | Keys and keyways should not have looseness, deformation, or abnormal wear. | |
Splines | No abnormal wear or deformation. | |
Rolling Bearings | No damage or cracks. | |
Oil Seals | No cracks on the mating surface. | |
케이블 | Repeat checks as per monthly inspection requirements. | |
Collector | Repeat checks as per monthly inspection requirements. | |
Insulation Resistance | Insulation resistance to ground should be no less than 1.5 MΩ. | |
Resistance Between Live Parts and Grounding Screws | Should not exceed 0.19 Ω. |
Regular lubrication of the wire rope and other moving parts is crucial for minimizing friction, wear, and corrosion. Use lubricants specified by the manufacturer and apply them according to the recommended schedule.
Conduct a load test annually or according to local regulations and manufacturer requirements. This ensures that the crane can safely handle its maximum rated load and helps identify potential issues under operational stress.
Prevent Adverse Conditions: If the crane is used in harsh environments, such as those with high humidity, dust, or corrosive substances, increase the frequency of wire rope hoist inspections and maintenance to counteract these conditions.
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