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.