Maintenance and upkeep instructions for the traveling mechanism of a portal crane

The traveling mechanism of a portal crane is responsible for the movement and positioning of the entire machine. It consists of components such as a traveling motor, reducer, wheel sets, brakes, rails, rail clamps, buffer devices, and transmission couplings. It is subjected to heavy loads, sea breezes, salt spray, and bumpy impacts over long periods, making it a high-risk area for malfunctions. Proper daily maintenance can prevent problems such as traveling mechanism jamming, rail wear, wheel wear, and slippage, ensuring the safe operation of the entire machine. The key maintenance points and precautions during use are explained below.

I. Pre-Operation Inspections (Mandatory for Every Shift)

1. Wheel and Rail Inspection: Inspect the wheel flanges and treads for cracks, missing pieces, and severe wear; replace wheels with flanges worn beyond the standard thickness. Check the rail surface for debris, gravel, and welding slag; ensure the rail clamps are secure and not loose, and that the rails are not obviously deformed. Observe the wheel-rail fit for any signs of wear; promptly investigate and adjust any wheel edge wear or rail side scratches.

2. Brake and Rail Clamp Inspection: Inspect the travel brakes for excessive wear on the brake shoes, uniform clearance, and sensitive and reliable braking action without slippage or abnormal noise. The rail clamp is a key windproof device; before operation, confirm that the clamp's opening and closing action is normal, and that the clamping surfaces are free of oil and wear. In windy weather, the rail must be reliably clamped; never use a faulty rail clamp.

3. Transmission Component Visual Inspection: Ensure all coupling bolts are complete and tightened; check for cracks and aging in the elastic buffer components; and ensure the gearbox is free of oil leaks. The travel motor casing is intact, the junction box is securely sealed to prevent corrosion from rainwater and salt spray, and the motor operates without abnormal noise.

4. Buffer Device Inspection: The buffers at both ends are intact, without damage or deformation, the buffer springs are not broken, and they are properly aligned with the end stops of the track to prevent overtravel and impact.

II. Key Points for Regular Maintenance

1. Lubrication Maintenance

Travel Reducer： Regularly check the oil level according to the equipment manual, and replenish or replace gear oil as needed. Operation without oil is strictly prohibited. Pay attention to oil cleanliness; replace the oil immediately if emulsification or impurities appear.

Wheel Bearings and Hinge Pins：Regularly add grease. In coastal dock environments with high salt spray, appropriately shorten the lubrication cycle to prevent bearing corrosion and jamming.

Caution：Do not apply grease to wheel treads, brake shoes, or rail clamps during lubrication to prevent slippage and failure.

2. Fastener Tightening Inspection

Regularly check the bolts on the travel mechanism base, wheel bearing housing bolts, rail pressure plates, and coupling bolts. The portal crane experiences significant impact during travel and start-up, making bolts prone to loosening. Tighten any loose bolts to the specified torque. Replace any missing bolts promptly; do not use defective or substitute fasteners.

3. Transmission System Inspection： Listen to the operating sounds of the reducer and motor. Immediately stop the machine and investigate if abnormal noises or excessive vibrations are detected. Replace any aged, cracked, or detached rubber parts of the flexible coupling promptly to prevent damage from transmission impacts.

4. Wheel and Rail Wear Troubleshooting: Regularly measure the wheel track and diagonal, and check for wheel horizontal and vertical misalignment. If rail wear occurs, do not continue operation; stop the machine and investigate: wheel installation misalignment, track deformation, asynchronous travel motors on both sides, and inconsistent braking force can all cause rail wear. Only resume operation after adjustments are made to ensure the issues are resolved.

5. Wind Protection Device Maintenance: Regularly test the operation of rail clamps and anchoring devices, and remove rust and dirt from the clamping parts; check the accuracy of the limit switch signals on the rail clamps. Before typhoons or strong winds, in addition to tightening the rail clamps, proper anchoring should be ensured; wind protection cannot rely solely on the travel brake.

6. Electrical Component Maintenance: Regularly inspect the travel motor, cables, and limit switches. The travel limit switches (end-point limit switches) must be effective and reliable; short-circuiting the limit devices is prohibited. Ensure cables are free from damage, dragging scratches, and short circuits/leakage.

III. Prohibitions and Precautions During Use

1. When the portal crane is moving, no one should stand on the ground or on the track area. Sound the warning bell before moving and confirm there are no obstacles within the track area before operation.

2. High-speed sudden starts and stops are prohibited. Under heavy load conditions, minimize frequent movement, as large impacts will accelerate damage to the wheels, reducer, and bolts.

3. If the crane stops moving on one side, veers off course, makes abnormal noises, or the brakes slip, immediately disconnect the power to the traveling mechanism. Do not force movement to prevent motor burnout and wheel damage.

4. At outdoor docks, if strong winds reach the specified wind speed, do not attempt to move the crane. Position it immediately and engage rail clamps and anchor windproofing devices.

5. Avoid moving the crane when there is water or ice on the track to prevent wheel slippage. Clean salt and mud from the track promptly to reduce wheel wear.

6. When repairing the traveling mechanism, the main power supply must be disconnected, and a warning sign must be posted. Inspect the wheels and brakes, and ensure the entire machine is protected against slippage to prevent accidental equipment movement.

IV. Fault Record and Ledger Management Establish a maintenance ledger for the traveling mechanism, recording lubrication, bolt tightening, wheel wear, brake maintenance, and rail clamp testing. Replace wheels, brakes, and bearings promptly when they reach wear and tear standards; operation of equipment with defects is strictly prohibited. Track and rectify any issues such as rail wear, oil leaks, or abnormal noises to prevent minor faults from escalating into major safety accidents.