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Overhead Crane Terminology

Updated: Dec 3, 2020

Overhead CranesMove in 3 Directions:


  • Length, the length of a building or bay.

  • Width, the width of a building or bay.

  • Height, up or down.

  • The part of the crane moving the length is called the Bridge.

  • The part of the crane moving the width is called the trolley.

  • The part of the crane moving up and down is called the hoist.

  • These three parts, bridge, trolley, and hoist together are called a crane or overhead crane.


The following is a glossary of terms related to overhead cranes:


BAY: The space between the building frames measured parallel to the ridge of the building.


Brake: A device for retarding or, stopping motion by friction or by power means.


Bridge: a part of an overhead crane consisting of girders, trucks, and drive mechanism which carries the trolley and travels the length of the runway.


Building Aisle: A space defined by the length of a building and the space between building columns.


Capacity: the Maximum rated load (in tons) which a crane is designed to handle.


Collectors: Contacting devices for collecting current from the runway conductors. The mainline collectors are mounted on the bridge to transmit electrical current from the runway conductors.


Crane Aisle: That portion of the building aisle in which the crane operates, defined by the crane span and the uninterrupted length of the crane runway.


Crane girder: The principal horizontal beams of the crane bridge which supports the trolley and is supported by the end trucks.


Crane Span: the horizontal distance center to center of the runway beams.


Hand Geared: The operation of the bridge, hoist, or trolley of a crane by the manual use of chain and gear without electric power.


Hoist: a Machinery unit that is used for lifting and lowering a load.


Holding Brake: a brake that automatically prevents motion when the power is off.


Lift: The maximum safe vertical distance through which the hook can move.


Limit Switch: A device designed to cut off the power automatically at or near the limit of travel for the crane motion.


Pendant Push Button Station: Means suspended from the crane for operating the controllers from the floor or other level beneath the crane.


Rated load: The maximum load a crane is designed to handle.


Remote Operated Crane: a crane controlled by Radio Remote Controls.


Rotating Axle: An axle which rotates with a wheel.


Runway: The rails beams, brackets, and framework on which a crane operates.


Runway Conductors: the main conductors mounted on or parallel to the runway which supply electrical current to the crane.


Runway Rail: The rail supported by the runway beams on which the bridge travels.


Single girder Cranes: An electric overhead traveling crane having one main girder which supports a hoist mounted on a under running trolley.


Span: The horizontal distance center to center of runway rails.


(End)Stop: A device to limit the travel of a trolley or crane bridge. This device normally is attached to a fixed structure and does not normally have energy absorbing ability.


Support Column: A separate column which supports the runway beam of a top running crane.


Suspension system: The system (rigid or flexible) used to suspend the runway beams of under hung or monorail cranes from the rafter of the building frames.


Top Running Crane: An electric overhead traveling crane having the end trucks supported on rails attached to the top of the crane runway beams.


Under Running Crane: An electric overhead crane having the end trucks supported on track attached to the bottom flanges of beams or supported on the bottom flanges of the beams; these beams make up the crane runway.


Wheel Base: The distance from center to center of outermost wheels.


Wheel Load: The load without impact on any wheel with the trolley and lifted load (rated capacity) positioned on the bridge to give maximum loading.

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