Basic Working Principle of Overhead Crane

Brief Introduction of Overhead Crane

Bridge crane is a kind of bridge type crane whose bridge frame runs on elevated track, also known as overhead crane. The bridge frame of the bridge crane runs longitudinally along the rails laid on the elevated sides on both sides, and the lifting trolley runs horizontally along the rails laid on the bridge frame, forming a rectangular working range, which can make full use of the space under the bridge frame for hoisting and transporting materials. Hindered by ground equipment.
Bridge cranes are widely used in indoor and outdoor warehouses, factories, docks and open storage yards. In terms of general structure, overhead cranes can be divided into two types: single-girder overhead cranes and double-girder overhead cranes.

Basic Structure of Overhead Crane

The general-purpose bridge crane is generally composed of a bridge running mechanism, a lifting trolley, and a bridge metal structure. The lifting trolley is composed of three parts: the lifting mechanism, the trolley running mechanism and the trolley frame.

Crane Trolley

The lifting mechanism includes brakes, motors, reducers, drums and pulley blocks. The motor drives the reel to rotate through the reducer, so that the wire rope is wound on the reel or lowered from the reel to lift the heavy object. The trolley frame is a frame for supporting and installing components such as the lifting mechanism and the trolley running mechanism, and is usually a welded structure.

The driving mode of the crane operating mechanism can be divided into two categories: one is centralized drive, that is, one motor is used to drive the long drive shaft to drive the driving wheels on both sides; the other is separate drive, that is, the driving wheels on both sides use one Electric motor drive. Medium and small bridge cranes mostly use the "three-in-one" drive mode that combines brakes, reducers and motors. Ordinary bridge cranes with large lifting capacity are easy to install and adjust. The drive device often uses a universal coupling. 

Crane Operating Mechanism

The crane operating mechanism generally only uses four driving and driven wheels. If the lifting capacity is large, the method of adding wheels is often used to reduce the wheel pressure. When there are more than four wheels, a hinged balance frame device must be used to distribute the load of the crane evenly on each wheel.

Bridge Metal Structure

The metal structure of the bridge is composed of main girders and end girders, which are divided into two types: single main girder bridge and double girder bridge. The single girder bridge consists of a single main girder and end girders located on both sides of the span, and the double girder bridge consists of two main girders and end girders.

The main girder is rigidly connected with the end girder, and the two ends of the end girder are equipped with wheels to support the bridge running on the elevated. Rails are welded on the main girder for the trolley to run. There are many structural types of the main girder of the bridge, and the typical ones are box structure, four-truss structure and vierendeel truss structure.

The box-shaped structure can be divided into several types such as off-track box-shaped double girders, off-track box-shaped single main girders, and regular-track box-shaped double girders. The regular box-shaped double girder is a basic form widely used. The main girder is composed of upper and lower flange plates and vertical webs on both sides. The trolley rail is arranged on the center line of the upper flange plate. Its structure is simple. It is easy to manufacture and is suitable for mass production, but it has a large dead weight.

The section of partial rail box-shaped double girder and partial rail box-shaped single main girder is composed of upper and lower flange plates and main and auxiliary webs of unequal thickness. The slab can be omitted, and the off-track box-shaped single main girder is replaced by a wide-flange box-shaped main girder for two main girders. The self-weight is small, but the manufacturing is more complicated.

Why Custom a Crane Solution?

At Yuantai, we know that there is no "one size fits all" in the lifting field. Universal cranes are suitable for general factories, warehouses, etc. Besides, different applications have different needs for cranes. For example, steel industries often lift steel plates, so need electromagnetic cranes. Ports and docks often need to load ore, gravel, and other bulk goods, so need to grab bucket cranes. Chemical dangerous places often need to carry flammable and explosive materials, so need explosion proof cranes.

So, we provide customized cranes according to the special needs of our customers. Custom crane solutions offer many benefits in a variety of applications：

Hoist

Overhead Crane

Gantry Crane

Jib Crane

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I'm happy to help you with a crane solution and pricing. Please provide me with the following crane specifications:

1. What type of overhead cranes do you need? (i.e., overhead crane, gantry crane, etc.)
2. What lifting capacity do you need for your overhead crane?
3. What span of crane do you need? 
4. What lifting height of overhead cranes do you need? 
5. What material will the crane lift? (i.e., steel, concrete, etc.)
6. Will the crane be used indoors or outdoors?
7. Any special requirements for the crane? (i.e., explosion-proof, etc.)

If you have any crane needs, please contact us online or email us at cherry@ytcrane.com. WhatsApp/WeChat：+86 15093126500 . Our crane engineers will give you a suitable crane solution and a specific crane price within 24 hours.