Maintenance of Tower Crane

Release time：2022-05-04    Click：101

Comply with JGJ196‑2010 and GB5144 standards. Maintenance is divided into daily, weekly, monthly, quarterly, annual and special‑condition maintenance, covering steel structures, mechanisms, wire ropes, brakes, safety devices and electrical systems.

I. Daily Maintenance (Per‑shift, performed by operator)

Complete machine and foundation: No cracking, settlement or water accumulation on foundation; anchor bolts free of looseness; counterweights without damage or displacement; no oil leakage or sundries on whole machine.

Steel structure: Visually inspect standard mast sections, jib and counter‑jib for deformation, weld cracking and cracks; walkways, guardrails and ladders shall be intact.

Wire ropes, sheaves and hook: Wire ropes free of broken wires, kinks and flattening; sheaves rotate flexibly; hook anti‑drop latch is in good condition.

Brakes: Hoisting, luffing and slewing brakes act sensitively, free of oil contamination; manual brake release functions properly.

Safety limit devices: Perform no‑load test for load‑moment limiter, weight limiter, height limit, luffing limit and slewing limit to confirm effectiveness.

Lubrication: Apply grease to pin shafts and sheaves as required; check oil level of reduction gearboxes.

Electric system: Cables without damage; emergency‑stop button valid; reliable earthing; operating handles return to zero position.

After operation: Release slewing brake; cut off main power supply; fill in hand‑over record.

II. Weekly Maintenance (Professional maintenance personnel)

Fully fasten bolts and pin shafts at all positions; split cotter pins shall be fully opened, no missing or substitute parts allowed.

Clean and apply grease to large slewing ring gear; inspect tooth surface for pitting and broken teeth.

Inspect trolley wheels and rails; lubricate trolley bearings; check trolley limit switches.

Inspect anchorage assembly: attachment frames, diagonal bracings, adjusting screw rods and building anchor seats free of looseness and deformation.

Inspect hydraulic jack‑up system: oil level and leakage; guide roller clearance and anti‑drop device of climbing pawls shall be intact.

Clean dust on cable drum and slip ring; check carbon‑brush wear.

III. Monthly Maintenance (At least once a month, keep records)

High‑strength bolts: Retorque bolts for standard sections, slewing support and anchorage with torque wrench to meet torque value specified in manual; apply anti‑rust grease on threads.

Double‑nut anti‑loosening for standard‑section bolts; bolt shall extend out of nut by no less than 3 threads.

Tower verticality measurement: Independent height ≤4‰; under attached condition ≤2‰. Measure under wind speed ≤3 m/s.

Reduction gearboxes: Check oil quality and oil level; unclog breather plug; inspect for leakage, abnormal noise and overheating.

In‑depth brake inspection: Replace brake pads when wear exceeds 50 % of original thickness; brake wheel free of grooves and cracks; no plastic deformation on springs.

Comprehensive wire‑rope inspection: Evaluate broken wires, wear, corrosion and deformation per GB/T5972. Replace immediately if exceeding limits; reliable wire‑rope end fixation and rope clamps.

Calibration of safety devices: Load calibration for load‑moment limiter and weight limiter; anemometer and obstacle light work normally.

Electrical system: Check cable insulation; fasten terminals; earthing resistance ≤4 Ω.

IV. Quarterly Maintenance

Disassemble and inspect slewing mechanism; retorque all slewing‑support bolts; check gear meshing condition.

Hydraulic jack‑up system: Sample hydraulic oil; replace oil if emulsified or contaminated. Verify balance valve / hydraulic lock function; direct connection between hose and cylinder is prohibited.

Visual inspection of key welds on steel structure; repair anti‑corrosion coating on corroded areas.

Inspect motor carbon brushes; replace when over‑worn; clean dust inside motors.

V. Annual Maintenance (Overhaul level)

Derust and apply anti‑corrosion coating for whole steel structure: primer plus topcoat. Repair or replace deformed / cracked components.

Disassemble, clean reduction gearboxes; replace gear oil and oil seals; inspect gear wear.

Fill lubricating grease for motor bearings; replace oil in fluid coupling.

Professional calibration and verification for all safety devices.

Comprehensive inspection of cables and contactors, limit switches; replace aged components.

Complete special inspection of whole machine; establish maintenance file.

VI. Maintenance under Special Working Conditions

Before & after jack‑up / section‑lowering: Focus on jack‑up cylinder, climbing pawls, sleeve frame guide rollers and steps of standard mast sections. Jack‑up operation is forbidden with faults.

After heavy wind or rain: Remeasure tower verticality; re‑inspect foundation, anchor bolts and anchorage assemblies; check damage of cables and steel structures.

Storage when out‑of‑service for more than 1 month: Clean whole machine and apply anti‑corrosion treatment; moisture‑proof protection for electric parts; release slewing brake. Perform full‑range monthly maintenance before re‑commissioning.

After disassembly‑reassembly for relocation: Conduct maintenance equivalent to annual overhaul; replace all damaged components before putting into service.

VII. Key Component Scrap Criteria

Wire rope: Scrap immediately if broken‑wire count within one lay exceeds standard, severe corrosion, kinking, flattening or bird‑cage distortion occurs.

Brake assembly: Replace brake pads with wear over 50 %; replace brake wheel when groove depth reaches 1.5‑2 mm; replace springs with plastic deformation.

High‑strength bolt: If cracks, elongation or thread damage occurs, do not retighten for reuse; replace directly.

Structural components: Components with main chord cracks, weld cracks or plastic deformation shall not be simply repaired by welding; evaluate per relevant specifications.

Important Reminder

All maintenance work must be documented in hard‑copy records. Major repairs shall be performed by qualified institutions.