Due to long-term high-frequency operation, complex working conditions, improper handling, or inadequate maintenance, jib cranes are prone to issues such as jerky movement, brake failure, abnormal lifting, sluggish rotation, and electrical faults, all of which directly impact production efficiency and operational safety. Based on equipment structural principles and real-world failure cases, this analysis systematically outlines the causes, troubleshooting methods, and repair strategies for common jib crane faults, providing technical support for rapid maintenance and fault resolution.
Jerky movement and abnormal noises are the most common faults, primarily categorized into issues with jib rotation and hoist travel. Jerky jib rotation and abnormal slewing noises are mainly caused by a lack of lubrication in the slewing bearing, bearing wear or aging, debris obstruction, or reducer malfunctions. Troubleshooting steps include clearing debris from the slewing mechanism and checking bearing lubrication; if the bearing is dry, apply specialized grease. If the fault persists after lubrication, disassemble the unit to inspect the degree of wear and replace the bearing immediately if wear limits are exceeded. Simultaneously, check the lubricant in the cycloidal pin-wheel reducer—replenishing or replacing it if the oil is contaminated or the level is low—and adjust the gear transmission clearance. Jerky movement and abnormal noises during electric hoist travel along the main beam track are usually caused by track deformation, surface burrs, travel wheel wear, or wheel gauge misalignment. Corrective measures include calibrating track flatness, grinding away burrs, replacing worn travel wheels, and adjusting wheel clearance to ensure smooth operation against the track.
Abnormal lifting faults fall into three categories: jerky lifting/lowering, insufficient lifting power, and load slippage. Jerky movement is often caused by wire rope misalignment, chain jamming, or deformation of the rope guide; solutions involve realigning the wire rope, straightening the rope guide, and clearing debris causing the chain jam. Insufficient lifting power is likely due to motor power degradation, reducer transmission failure, or unstable voltage; troubleshooting requires checking the supply voltage and motor operating parameters, inspecting reducer transmission components, and replacing worn or aged parts. The "hook slippage" malfunction poses a severe hazard, primarily caused by excessive brake pad wear, slack brake springs, or excessive brake clearance. Addressing this requires dismantling the braking assembly to replace worn pads and adjust spring tension and clearance, ensuring a tight brake engagement and immediate locking upon power cutoff.
Electrical system malfunctions typically manifest as failure to start, start/stop control issues, or limit switch failure. Failure to start is often due to power circuit breaks, loose wiring, an un-reset emergency stop button, or triggered overload protection; troubleshooting should prioritize checking power lines, terminals, and the emergency stop status, as well as resetting the overload protection device. Start/stop malfunctions usually stem from aging or damaged control buttons or contactors, requiring the direct replacement of the faulty electrical components. Limit switch failure represents a major safety hazard, often caused by switch displacement, contact oxidation, or broken wiring; corrective measures include recalibrating the switch position, cleaning oxidized contacts, and repairing broken wires, followed by necessary testing and verification before the equipment is returned to service. After any repair, the equipment must undergo both no-load and load test runs to confirm the fault has been completely eliminated before resuming normal operations.
