what is eot crane, how much do you know about it?

What Is EOT Crane?

EOT crane, whose full form is electric overhead travelling crane, is a kind of widely used lifting equipment for material lifting in the workshop, warehouse, and material field. The operation range of a EOT crane is constructed as rectangular, due the crane span structure on a bridge crane can realize longitudinal operation along both sides of the rail laid on the elevated frame, while the lifting trolley can realize horizontal operation along the rail laid on the crane span structure. Because of the unique structure, the crane can take full advantage of the space under the crane span structure to lift material from the ground without be hindered. This kind of crane is widely used in various of fields like indoor and outdoor warehouse, factories, wharf, and outdoor material storage yard, etc.

EOT Crane Application

EOT crane is an important tool and equipment in the production process of modern industrial production and transportation. So the overhead travelling crane have been widely used in the indoor and outdoor industrial and mining enterprise, iron and steel industry, railway transportation, port terminals, logistics, and other departments and places.

EOT Crane Design

Trolley

The EOT crane is composed of hoisting mechanism, trolley running mechanism, and trolley frame. Hoisting mechanism including electric motor, brake, reduction gear, drum, and block and tackle. Electric motor drives the drum to rotate through the reduction gear, and make wire rope wound on a reel or put down from the reel to lift heavy weights. The trolley frame which is usually adopted welding structure, is a rack used to support and install the hoisting mechanism and the trolley running mechanism.
Rotation Mode of the Trolley
The rotation mode of trolley is divided into two different types according to the installation position of the reduction. One type is installing the reduction in the middle of the active wheel, so that the torque on the trolley reduction and the two sides of the rotating shaft is more balance. Another kind is installing the reduction on one side of the active wheel, this kind of method provides a great convenience on installation and maintenance, but the trolley body twist will be unstable.

EOT Crane Control

The heavy weights should be moved along the up, down, left, right, front, and back direction, and can be moved in vertical direction at the same time.
There must be a reliable brake device, even in the case of power outages, heavy loads will not fall due to weight.
There should be a large speed range, at the beginning of the static state, the crane should be started gradually accelerated from a low speed, and the acceleration should not be too big.
In order to prevent possible danger because of overload or speeding, short-time overload protection measure is essential. Over current relay is generally used as the circuit overload protection.
Missing-voltage protection should be set up.
Necessary security measures are also essential.

EOT Crane Driving Mode

Concentrated driving, which uses an electric motor to drive the long drive shaft so that drive the active wheel on both sides;

Separately driving, that is, both sides of the active wheel are drived by a motor drive;

Three in one" driving method, the brake, the reducer and the electric motor assembly as one of the driving mode.

The Crane Span Structure Running Mechanism

Metal Structure of Crane Span Structure

The crane span structure consists of main girder and end carriages, and it can be divided into two types – monogirder crane span structure and double girder crane span structure. The nomogorder crane span structure consists of a main girder and end carriages on both sides of the span, while a double girder consists of two main girders and end carriage. The connection between main girder and end carriages adopts rigid connection method, the two sides of end carriages are equipped with wheels, used to supported crane span structure running on the overhead frame. What’s more, a rail is welded on the main girder for trolley running. There are various types of the main girder structure, the typical ones are as follows:

Box Structure

On track box double girder is a widely used basic form, the main girder consists of the upper and lower flange plate and both sides of the vertical web, trolley rail is arranged on the center line of the flange, which with many advantages like simple structure, easy fabrication, suitable for batch production, but gravity is bigger.
The cross sections on both partial rail box double girder and partial rail box single girder all composed with upper and lower flange plate, or web plate with different thickness. The trolley rail is placed above the main flange plate, short stiffening plate into the box can be saved, The partial rail box single girder consists of a wide flange box girder instead of two main girder, whose heavy is small, but the manufacturer process is more complicated.

Four Braced Structure

This kind of crane is constructed into a enclosed space structure by four pieces of plane truss, the surface level of the truss is generally covered by bedplate with light weight and large stiffness, but compared with other structure, four braced structure has less production because of its bigger size, complex manufacturing process and lower fatigue strength, compared with other structure.
Vierendeel truss structure
Similar to the partial rail box main girder, vierendeel truss structure is constructed into a enclosed space structure by four pieces of plane truss. In addition to the main web is solid i-section girder, the rest three pieces of sheet metals are cut into many windows according to design requirements, formed into a vierendeel truss without diagonal. The upper and lower horizontal truss surface are covered by bedplate. What’s more, the operation mechanism and electrical equipment are installed inside the bridge frame, with light weight and large stiffness, this kind of structure is a widely used type.


Double Girder EOT Overhead Crane	Single Girder EOT Overhead Crane

EOT Crane Operating Mode

Ordinary bridge crane is mainly used in electric power, usually in the driver's interior control, but also has a remote control. Lifting weight comes up to 500 t, and the span comes up to 60 meters. In order to facilitate the installation and adjustment, the large lifting weight of ordinary bridge crane drive device often uses universal coupling. The crane operation mechanism generally consists of only 4 active and driven wheels, if the weight is great, commonly used to increase the wheel to reduce the wheel pressure. When the wheel is more than 4, the articulated frame device must be used, so that the load of the crane can be distributed evenly on each wheel.

The Simple Beam Bridge Crane

This kind of crane is also known as beam crane, whose structure is similar to the ordinary bridge crane. Lifting weight, span and working speed are smaller, and the structure is similar to the ordinary bridge crane. The girder bridge is a simple beam, which composed of I-shaped steel beam or other types of steel beam and steel plate, hand hoist or electric hoist with a simple trolley as a lifting trolley, and the trolley usually runs on the lower flange of the beam. The bridge frame can be run along an elevated rail, or run along a rail suspended under the elevated. This kind of crane is called as a suspension beam crane.

Foundry Crane

The foundry crane is a member of bridge crane family and specifically used in the metallurgical plant. This kind of crane may be involved in the process of steel production, whose structure is similar to the ordinary bridge crane, but there is also a special working mechanism or device on the lifting trolley. The crane is characterized by frequent using, poor operating condition, and higher working level. There are five main types:

casting crane

soaking pit crane

stripping crane

charging crane

forging crane

Explosion-Proof Bridge Crane

This kind of crane is mainly used to lifting heavy material in the environment of explosive gas. The basic structure is similar to the ordinary bridge crane, but in the mechanical parts like motor and electrical parts and metal contact surface are taken explosion-proof measures to ensure the safety of the using in explosion-proof environment. Explosion-proof bridge crane can be divided into two types according to explosion-proof categories:

Explosion-proof bridge crane used in coal mine

Explosion-proof bridge crane used in factory