What's the overhead crane?

An overhead crane, which is operated in elevated orbit, is also known as the skycar.Bridge crane bridge along the laid on on both sides of the elevated rail longitudinal operation, lifting trolley along the bridge is laid on the orbits of the horizontal run, constitute a rectangular scope of work, can make full use of bridge the space below the lifting materials, from the ground equipment obstacles.The crane is widely used in indoor and outdoor warehouses, factories, wharves and outdoor storage areas.

Ordinary bridge

Composition:

Lifting trolley consists of lifting mechanism, car running mechanism and trolley frame.The lifting mechanism includes motors, brakes, reducers, rolls and pulley blocks.The motor drives the drum through a reducer, which causes the wire rope to wound up or down from the reel to lift heavy objects.The trolley frame is a frame for supporting and mounting parts such as lifting mechanism and car running gear, usually welded structure.

The way the car turns

Car way of rotation is different according to the installation position of reducer is divided into two kinds, one kind is installed in the middle of the car driving wheel, let the car speed reducer output shaft and the axis of rotation on both sides of the torque is uniform,The other type of speed reducer is installed on the side of the car's active wheel, which is convenient for installation, maintenance and maintenance, but there will be a situation of uneven torque of the car body.

Bridge running mechanism

The metal structure of the bridge

The main beam and the end beam are composed of single main beam bridge and double beam bridge.The single main beam bridge is composed of single main beam and the end beam on both sides of the span. The double girder bridge is composed of two main beams and the end girders.The main beam is rigidly connected with the end beam, and the ends of the end beam are equipped with wheels, which are used for supporting the bridge to run on the elevated frame.The main beam is welded with rails for lifting trolley.The structure type of girder is more typical.

1. Box structure

(1) the right box double girder is a basic form of widely used, by upper and lower flange plate girders and on both sides of the vertical web, rail car arrangement in the center of the line on the flange, its simple structure, easy fabrication, suitable for batch production, but gravity is bigger.

Box (2) partial rail double beam and rail box single girder cross section are ranged from upper and lower flange plate and the thickness of main and deputy web, rail car is decorated in the main web above, the casing short stiffening plate could save, in which partial rail box single main box girder is composed of a wide flange instead of two main girder, the weight is small, but made more complex.

The four truss structure

By 4 pieces of plane truss assemble enclosed space structure, on the surface level on the truss generally covered by bedplate, weight light, stiffness big, but compared with other structures, appearance size, made more complex, the fatigue strength is low, have less production.

3. Hollow truss structure

Similar partial rail box girders, a closed structure consisting of 4 pieces of steel, in addition to the main web for solid abdomen i-section girder, rest 3 piece of sheet metal in accordance with the design requirements of cutting into many window, form a vierendeel truss without diagonal, in the upper and lower levels of truss surface covered by bedplate, crane running mechanism and electrical equipment installed inside the bridge, weight is lighter, the overall stiffness is large, it is more widely used in China a type.

Driving mode:

1. Centralized drive, with an electric motor driving the driving wheels of the two sides of the long drive shaft;

2. The drive of the active wheel on both sides is driven by one motor;

3. "three-in-one" driving mode, which is the driving mode of the combination of brake, reducer and electric unit.

Operation mode:

Ordinary bridge crane mainly USES electric power drive, usually in the driver interior control, also have remote control.The weight can be up to 500 tons and can span up to 60 meters.The ordinary bridge crane with large weight is easy to install and adjust, and the driving device often adopts universal coupling.The crane operation mechanism generally USES only 4 active and driven wheels, if the weight is very large, it is commonly used to increase the wheel to reduce the wheel pressure.When the wheel is more than 4, it must use the hinge balancing frame to distribute the load evenly on the wheels.

Simple bridge type

Also known as beam crane, its structure composition is similar to ordinary bridge crane.The weight, span and speed of work are small.Bridge girder is composed of steel and plate steel beams or other simple beam, with chain or electric hoist with simple and easy as lifting trolley car, the car at the bottom flange of the h beam.The bridge can be operated on an elevated rail or in an orbit suspended below the elevated frame, which is called a suspended beam crane.

Metallurgical special bridge type

This kind of crane can participate in certain technological operation in the process of steel production. The basic structure is similar to that of ordinary bridge cranes, but there are special working organs or devices in the crane trolley.This type of crane is characterized by frequent, poor conditions and high working level. There are five main types:

1. Casting crane:

It is used for the injection of ladle, ladle, ladle and ladle.The main trolley is hoisted into a barrel, and the vice car is turned into a bucket and other auxiliary work.

2. Clamping crane:

Use clamp to lift the high temperature ingots vertically to the pit soaking pit or remove it into the ingot cart.

3. Removal crane:

To force the ingot out of the ingot mould.There are specialized deinking devices on the trolley, and the way of deinking is determined according to the shape of the ingot mould: some deinking cranes hold the steel ingots with the top lever and lift the ingot mould with the tongs;Some use the clamps to hold the ingot mould and use the tongs to lift the ingots.

4. Loading crane:

Used to add a furnace to an open furnace.The bottom of the main car is mounted with a pole, which is used to pick up the box and send it to the furnace.The main column can rotate around the vertical axis, and the poles can be swung up and down.The auxiliary car is used to repair the furnace.

5. Forged crane:

Used for forging large workpieces with hydraulic press.Special tilting machine is mounted on the main trolley hook to support and reverse the workpiece.The auxiliary car is used to lift the workpiece.

Explosion-proof bridge

This kind of crane is mainly used in explosive gas environment lifting is used, the basic structure similar to ordinary bridge crane, but in the electrical and electrical parts and mechanical parts of the metal contact surface explosion protection measures, to ensure the safety of explosion-proof environment use.Explosion-proof bridge crane can be divided into two types according to explosion-proof type:

1. Explosion-proof bridge crane for coal mine:

It is mainly applied to the underground part of coal mine shaft and the non-excavated surface part of the mine. The crane should have the coal safety certificate (MA certification).

2. Factory explosion-proof bridge crane:

It is mainly used in dangerous and important places such as flammable gas or combustible mixture. The crane should have the explosion-proof certificate issued by the national testing center.

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