When we talk about overhead cranes, here is what all it consists of –
HOOK – The lifted load is supported using a hook which connects to the hoist.
HOIST – The hoist is what makes the lift and holds, raises, or lowers the load using wire rope or chain. Hoists can be powered manually (by hand), with electricity, or with compressed air (pneumatic).
TROLLEY – The trolley supports the hoist and moves horizontally along the Crane Bridge, to position the hoist and hook, prior to picking up or lowering a load.
BRIDGE – A load-bearing beam that runs the width of the building. This is the primary structural component that connects the runways and moves the hoist forward and backward using a trolley.
A bridge can be comprised of one or two beams—more often referred to as a single girder or double girder design. Girders can be made of rolled steel or can be fabricated by welding the beams into a steel box design.
RUNWAY RAIL OR TRACKS– Rail supported by the runway on which the crane travels. Top-running cranes typically run on ASCE/railroad rails. Gantry cranes can also utilize a rail or track system installed in the floor to move the bridge back and forth.
END TRUCKS – Located on either side of the bridge, the end trucks move the bridge up and down the runway utilizing a series of wheels that ride on the rail. Each end truck can have a configuration of 2, 4, or 8 wheels based on the crane’s capacity.
CONTROLS – Controls are typically mounted in a panel on the crane or hoist and the pendant or remote radio console allows the operator to run the crane. The controls operate the drive and hoist motors, and can control Variable Frequency Drives (VFDs) to control hoist speed for precise load positioning.
ELECTRIFICATION – Insulated conductor bars or festoon systems (flat cables) bring power to the crane from the building.