As one of the main lifting equipment in industrial and construction industries, bridge crane plays an irreplaceable role. In fact, the working principle of the bridge crane is also very simple. It usually consists of and operates only three simple machines: levers, pulleys and hydraulic cylinders. Next, this article will introduce the working principle and working terminology of overhead crane in detail.
Terminology for Bridge Cranes
Axial load – total vertical force on the support structure of the jib crane
Box section – a rectangular cross-section at the intersection of beams, trucks, or other components
Trailing brake – locking system that does not require force to provide braking
Explosion proof – made of explosion-proof materials
Boom Lower Height (HUB) – The distance from the floor to the lower side of the boom
Lifting capacity – maximum lifting load of the crane
Lifting speed – the speed at which the lifting mechanism lifts the load
Operating speed – speed of crane mechanism and trolley
Span – the distance between the centerline of the wheels at both ends of the main beam
Two blockages – when the load hanging from the hook is stuck on the crane
Web plate – a plate that connects the upper and lower flanges of a beam to the web plate.
Wheel Load – The weight that a single crane wheel will bear (in pounds)
Workload – determined by the load rate, which can be light, medium, heavy, or ultra heavy
Driving Device of Bridge Crane
The driving device is the power device that drives the working mechanism. General driving devices include electric drive, internal combustion engine drive, manual drive, etc. Electric power is a clean and economical energy source, and electric drive is the main driving method for modern cranes.
Working Mechanism of Bridge Crane
The working mechanism of an overhead crane includes a lifting mechanism and a running mechanism.
1. The lifting mechanism is the mechanism for achieving vertical lifting of objects, therefore it is the most important and basic mechanism for cranes.
2. The operating mechanism is a mechanism that horizontally transports objects through a crane or lifting trolley, which can be divided into rail work and trackless work.
Overhead Crane Pickup Device
The pickup device is a device that connects objects to a crane through a hook. Use different types of pickup devices based on the type, form, and size of the suspended object. Suitable equipment can reduce the workload of employees and greatly improve efficiency. The basic requirements for preventing the winch from falling and ensuring the safety of workers and equipment without damage to the winch.
Overhead Travelling Crane Control System
Mainly controlled by the electrical system to manipulate the entire movement of the crane mechanism for various operations.
Most bridge cranes start working vertically or horizontally after picking up the lifting device, unload at the destination, empty the travel to the receiving location, complete a working cycle, and then proceed with a second lifting. In general, lifting machinery performs material extraction, handling, and unloading work in sequence, with corresponding mechanisms working intermittently. Lifting machinery is mainly used for handling single items of goods. Equipped with grab buckets, it can handle loose materials such as coal, ore, and grain. Equipped with buckets, it can lift liquid materials such as steel. Some lifting machinery, such as elevators, can also be used to carry people. In some cases, lifting equipment is also the main operating machinery, such as loading and unloading materials at ports and stations.
