CSCS Tower Crane key terms

A large geared bearing that connects the crane's upper rotating structure to the base or mast, allowing the jib and counter-jib to rotate as one unit under load.

The rearward arm of a tower crane that carries counterweights and often houses the hoist machinery, balancing the load moment produced by the jib and suspended load.

Ballast blocks fixed to the counter-jib to oppose the overturning moment created by a lifted load, keeping the crane stable within its designed capacity envelope.

A wheeled carriage running along the horizontal jib that carries the hoist rope and hook, allowing the load radius to be adjusted by moving in or out.

The long horizontal working arm of a tower crane along which the trolley travels; its length and configuration determine the maximum reach available at any given capacity.

The vertical lattice structure made of stacked sections that supports the slewing assembly and jib at height, transmitting loads down to the foundation.

A tower crane whose jib pivots up and down rather than carrying a travelling trolley, letting it raise the jib to work in tight or obstructed sites.

The engineered concrete pad, ballasted raft, or anchored base that transfers crane overturning and vertical loads into the ground and must match the manufacturer's specified design.

A hydraulic or mechanical assembly attached to the mast that supports the upper crane while a new mast section is inserted, raising the working height incrementally.

The controlled process of raising a tower crane on its own climbing frame and inserting additional mast sections to increase working height, performed under an engineered procedure.

The competent person appointed to plan, direct, and verify the assembly, climbing, or dismantling of a tower crane, ensuring the sequence and checks follow the manufacturer's instructions.

The product of the suspended load and its horizontal distance from the crane's slewing centre, used to assess overturning tendency against the crane's rated capacity.

The horizontal distance from the crane's slewing axis to the centre of the hook or load, which directly affects the capacity available at that position.

The manufacturer's table or graph showing the maximum permitted load for each combination of radius, jib configuration, and reeving, which the operator must consult before every lift.

The maximum load a crane configuration is permitted to lift at a stated radius and condition, as published by the manufacturer and reduced by any site-specific factors.

The maximum load that lifting gear or a crane may safely handle in a given configuration, usually the rated capacity reduced by an appropriate factor and marked on the equipment.

A multiplier applied to a sling's capacity to account for the increased tension in each leg as the angle between the legs and the vertical increases.

The selection, inspection, and attachment of slings, shackles, and lifting accessories to connect a load securely to the crane hook.

The documented check of a tower crane carried out before each shift or first use, covering structure, ropes, brakes, limiters, and safety devices for obvious defects.

A detailed inspection by a competent person at statutory intervals or after significant events, verifying the crane remains safe and recorded in the relevant register.

A device that stops a crane motion, such as hoist, trolley, or slew, before it reaches a dangerous end position, protecting the structure and preventing over-travel.

A safety device that senses load and radius together and prevents the crane from lifting or moving into an overload condition beyond its rated capacity.

An instrument mounted on the crane that measures wind speed, allowing the operator to stop work when limits set by the manufacturer or site rules are reached.

The maximum wind velocity at which lifting or specific crane operations may continue, specified by the manufacturer and often reduced for large-surface loads.

The exposed surface area of a load that catches the wind, increasing the force on the crane and often requiring reduced working limits in breezy conditions.

A setting that releases the slewing brake so the jib can turn freely with the wind when the crane is left unattended, reducing wind load on the structure.

A brake that holds or controls rotation of the upper structure; it must be released or set according to procedure so the crane can weathervane safely when out of service.

A defined height or zone below which the jib or load must not travel to maintain safe clearance from overhead obstructions such as power lines or structures.

A marked area beneath or around the crane, such as under the jib or near power lines, where people are prohibited from standing while lifting operations occur.

A competent person who directs the crane operator using agreed hand signals or radio communication, positioned to see both the load and the operator.

Standardised arm and hand movements used to instruct the crane operator when radio communication is unavailable or unreliable, agreed before the lift begins.

Two-way voice contact between the operator and signaller on an agreed channel, used to give clear, unambiguous instructions and confirm actions during lifting.

The wire rope that runs from the winch over sheaves to the hook block, raising and lowering the load; it must be inspected for wear, broken wires, and correct spooling.

The manufacturer's plan listing points to be greased or oiled, the correct lubricant, and the interval, keeping gears, bearings, and ropes in safe working condition.

A person with the training, knowledge, and experience to identify hazards and assess crane condition or operations, appointed to carry out inspections and examinations.

A documented assessment of a lift setting out the load, crane position, capacity checks, rigging, personnel roles, and controls for identified hazards before work starts.

The duties of the crane operator to be trained and authorised, follow the lift plan, conduct checks, refuse unsafe lifts, and record defects promptly.