Maintenance points for daily use of bridge cranes

What are the specific maintenance points for daily use of bridge cranes? Let's learn about them together with the editor from the bridge crane manufacturer.

As a core equipment in industrial production, the daily maintenance of bridge cranes is directly related to the stability, safety, and service life of the equipment. The following systematically outlines the maintenance points of bridge cranes from four stages: before operation, during operation, after operation, and periodic maintenance, combining specific methods and standards to ensure scientific maintenance work.

1. Pre-operation inspection: Build a solid safety line

Visual inspection of key components

Steel wire rope: Inspect for broken wires (replacement required if over 10% of single strands are broken or over 5% of the entire rope is broken), twisting, and corrosion (derusting and oiling required if over 10% of the area is corroded).

Hook: Observe whether the opening degree has increased (if it exceeds 15% of the original size, it needs to be scrapped) and the wear amount of the dangerous section (if it exceeds 10% of the original thickness, it needs to be replaced).

Brake: Test the braking effect (braking distance ≤ 0.2V, where V is the operating speed), and check the thickness of the friction plate (remaining thickness ≥ 50% of the original thickness).

Track: Clean the debris (such as welding slag and iron chips) on the track surface, and inspect the track joints for misalignment (deviation ≤1mm) and height difference (deviation ≤1mm).

Functional test of safety device

Limit switch: Manually trigger the upper and lower limits (trigger position ≥0.5m from the limit position), and the crane/trolley limits (trigger position ≥1m from the end), to confirm that the equipment has stopped running.

Overload limiter: Simulate an overload (apply 1.25 times the rated load) and observe whether the power supply is automatically cut off (response time ≤ 0.1s).

Windproof device: In open environments, it is necessary to check whether the rail clamps and anchoring devices are flexible (with a clamping force of the rail clamps ≥50kN).

Lubrication system inspection

Oil Level: Check the oil level of the reducer and gearbox (within ±5% of the scale mark), and the oil level of the hydraulic system (not less than 1/3 of the oil tank).

Oil quality: Observe the color of the lubricating oil (transparent and free of impurities is normal, turbidity or discoloration requires replacement), and viscosity (no granular sensation when twisted by hand).

II. Monitoring during operation: ensuring safety in real time

Observation of operating status

Vibration: Monitor the vibration values of the main beam and reducer with a vibration tester (such as VM-63C) (normal ≤ 4.5mm/s, exceeding the standard may cause structural fatigue).

Noise: Measure the operating noise using a sound level meter (such as TES-1350A) (normal noise level ≤ 85dB, abnormal noise may indicate bearing or gear wear).

Temperature: Use an infrared thermometer to measure the surface temperature of the motor and brake (normal temperature should be ≤65℃, as overheating may cause insulation damage).

Operational behavior norms

Smooth lifting: Avoid sudden acceleration or braking (acceleration ≤ 0.5 m/s²) to reduce mechanical impact (impact force reduced by 60%).

Vertical lifting: Monitor the angle between the lifted object and the vertical direction using a laser range finder (accuracy ±1mm) (adjust when the angle is greater than 3° to prevent the steel wire rope from coming off the groove).

No oblique pulling: When the oblique pulling angle exceeds 5°, the force on the steel wire rope increases by 30%, which is prone to fracture.

Handling of abnormal situations

Brake failure: Immediately press the emergency stop button and inspect the brake oil circuit for any oil leaks, and check the spring for any signs of fatigue or fracture.

Wire rope jumping: stop