Abnormal Signals During Daily Operation and Run
Abnormal Signals
Abnormal Sounds
A piercing scream: This usually indicates that the brake pads are excessively worn, and the metal parts are beginning to rub directly against the brake wheel (brake disc).
A dull thud or "clunk": This may indicate severe wear clearance in transmission components such as the brake arm pin, connecting rod, etc., or excessive travel of the electromagnet armature.
A continuous humming or vibration: For electromagnetic brakes, this may be due to the electromagnet not fully engaging or disengaging, causing jamming.
Abnormal Signals
Insufficient braking force (hook slippage): Under load, the hook or trolley continues to slowly slide down after braking. This is an extremely dangerous signal and requires immediate shutdown and inspection.
Delayed braking: After returning the operating handle to zero, the crane or trolley needs to slide a considerable distance before stopping.
Slow start: After releasing the brake, the mechanism does not start immediately, feeling as if it is "stuck." This may be due to the brake not fully opening (poor return).
Abnormal Signals
Abnormal Operation Feel
For lever-controlled brakes, the operator may notice a change in the "force" or "stroke" of the lever, such as it becoming too light or too heavy.
Abnormal Signals
The brake housing or surrounding area feels abnormally hot to the touch. Overheating accelerates liner wear, reduces the coefficient of friction, and can even lead to complete brake failure.
When is maintenance required?
1. Performance-wise: Any form of hook slippage, significantly increased braking distance.
2. Sensory-wise: Abnormal noise heard, burnt smell smelled, abnormally high temperature felt.
3. Inspection: Brake pads worn to their limit, brake drums with severe grooves or cracks, and pins found to be severely loose or jammed.
4. Maintenance Schedule: Maintenance should be performed at predetermined intervals, regardless of the condition.
Daily Inspection
Performed by crane operators before each shift, focusing on checking the above-mentioned "abnormal signals".
Weekly/Monthly Inspection
Performed by maintenance personnel with a more detailed visual inspection, cleaning, and operational testing of the brake.
Annual Comprehensive Overhaul
Completely disassemble the brake, clean all parts, inspect for wear, replace all worn parts (such as pads, pins, and seals), reassemble, and precisely adjust
Safety is paramount
Crane brakes are the last line of defense for equipment and personnel safety; any doubt about their condition should be considered sufficient grounds for immediate maintenance. Strict adherence to operating procedures and the manufacturer's maintenance manual is fundamental to ensuring the safe and reliable operation of the crane.
