Overhead Travelling Crane

Overhead travelling crane periodic inspection is the examination and testing, by authorised engineers, of lifting machines consisting of a bridge girder running on two support rails with a travelling trolley. The load-bearing structure, hoisting/travelling organs, brakes and electrical equipment are assessed. Unlike a monorail, the integrity of both bridge supports and the building rail system is also in scope.

Crane Type and Scope

Overhead cranes are classified as single girder, double girder, double trolley and gantry types. The trolley carries a wire rope or chain hoist. They are heavily used in workshops, warehouses, machine parks, foundries and shipyards. Main organs inspected:

• Bridge girders, end trucks and wheel sets
• Trolley: hoisting mechanism, rope drum, rope, hook, sheave block
• Brakes (hoist, long, cross travel) and limit switches (upper/lower, end limits)
• Rail system: support beams, rail clamps, buffers and end stops
• Electrical equipment: cabin, panels, festoon, earthing, pendant control

Periodic Inspection Items

• Rope examination: Broken wires, strand distortion, rust and diameter loss; discard decision against the strand/local damage criteria of the standard.
• Hook and sheaves: Throat opening, latch, sheave groove wear; free hook swivel under load.
• Brake tests: Hoist brake holding without slip at nominal load; measuring the stopping distance of travel brakes.
• Safety limiters: Upper/lower limit switches, end limit switch and load limiter; functional verification (cut-out test).
• Structure: Cracks and permanent deformation in girders and weld zones, bolt tightness, wheel rim flange wear and rail alignment (skew) measurement.
• Rail and supports: Column connections, clamp tightness, rail joints, buffer/end-stop integrity, bridge span measurement.
• Load and function: Hoisting/travelling test at nominal capacity; static-dynamic proof test after erection, relocation and important repair and at the intervals defined by the standard.

Legislation and Standards

Overhead cranes are subject to periodic inspection at least once a year under Law No. 6331 and the Work Equipment Regulation; under heavy duty the interval is shortened. Technical references: TS 10116 (general crane rules), the TS EN 13001 series (design of lifting appliances), TS EN 14492 for mechanisms, TS EN 60204-32 for electrical equipment, TS EN 1090 for steel structures and TS EN 12385-9 for in-service inspection of steel wire ropes. The rules on retaining rope test samples are also evaluated.

Risks and Operator Recommendations

The most fatal failure modes of an overhead crane are hook or rope failure, brake slipping and derailment. Rope override and spooling faults on the drum are precursors of a rupture; rope life must be tracked by lay count. Cabin personnel must be trained on emergency stop and escape plan. Material left on the rail or loose clamps trigger end-truck jamming and overturning moment; therefore a daily shift checklist (rope, hook, brake sound, limiter test) must be in the procedure. Overload (side pull and two-blocking) shortens fatigue life and is noted as operator warning in the report.

Outcome

At the end of the examination a signed report containing rope, hook, brake, limiter and structural findings is issued. Overhead crane inspections are within our Lifting and Handling Machines group. For similar duties review our Gantry Crane and Jib Crane pages, or contact us for your programme.