Electric Double Girder Gantry Crane

Electric double girder gantry crane is mainly used for loading and unloading operations in outdoor cargo yards, material yards and bulk cargoes. Its metal structure is like a door-shaped frame, with two legs installed under the main beam, which can move directly on the track on the ground. Both ends of the main beam can have overhanging cantilever beams, which has high site utilization, large operating range, and wide adaptability, strong versatility and other characteristics.

Electric double girder gantry crane structure

The electric double-girder gantry crane is composed of cart running mechanism, lower beam, outriggers, driver's cab, main girder, trolley running mechanism, lifting mechanism, escalator, electrical appliances and other components. Below are more details for the gantry crane components.

• Cart running mechanism

It is mainly composed of a lower beam and a trolley. The trolley is composed of a driving wheel set and a driven wheel set. The operating mechanism includes motors, reducers, gears, and wheel sets.

• Outriggers

The steel is used as the material, and then welded into a cage structure, the lower end is connected to the lower beam, and the upper end is connected to the main beam bolts through flanges.

• Driver's cab

The frame is made of section steel, and the shell is welded on the frame with thin steel plates. The driver's cab is closed with broken lines. The electrical appliances, power distribution cabinets and lines of the operating mechanism are generally located in the driver's cab.

• Main beam

The shaped steel and the steel plate are welded together, usually welded into a triangular truss frame, and on the main girder, there are trolley running rails.

• Car running mechanism

The main components are similar to the running mechanism of the trolley. The electric motor is driven by the reducer, and the small gear on the reducer is then transmitted to the large gear, so that the trolley can travel back and forth.

• Lifting mechanism

It is installed on the trolley frame, and the lifting movement is realized through the winch and the matching fixed pulley, movable pulley or hook.

Installation of electric double girder gantry crane

The installation is also divided into several parts, as follows:

• Preparations and precautions before installation

Be very familiar with the drawings and various technical materials. If there are errors or defects caused by improper transportation or storage, they should be corrected or eliminated in time, and can only be installed after correction or elimination.

Before installation, check whether the rotating parts are flexible, whether the connecting parts are firm, whether the bearings are short of oil, etc.

When the crane is transported or moved, collisions should be avoided. When lifting, the main beam should be fastened firmly. It is strictly forbidden to drag directly on the ground or the beam. There should be no standing water, otherwise the crane will be stripped and rusted.

• Installation of mechanical equipment

The erection of cranes can be divided into overall erection and partial erection according to the size of the equipment. Before erection, the quality of track installation should be checked and records should be made.

• Installation of electrical equipment

The electrical equipment installed on site includes: resistors, switches, control panels, floodlights, junction boxes, bridge parts, and welding of each threading pipe. The installation positions of resistors and control panels are allowed to be adjusted according to specific conditions.

The numbers of the start and end of all wires should be consistent with the schematic diagram to facilitate future installation and maintenance. If the cross-section of the wire is below 6mm², the wire connector can be used, but it should be tinned. If the wire is laid in the pipe, no joints are allowed.

There should be no rust on the contact surface of the slide wire, if any, it should be removed. The error of the horizontal and vertical centerlines of the angle steel sliding wires shall not be greater than ±20mm.

In terms of power and control circuits, when measuring the insulation resistance to the ground, all links of the electrical equipment need to be connected. The measured value should be less than 0.8 megohm, and the value of the insulation resistance between phases should not be too different. There will be a decrease, the lowest can be reduced to 0.4 megohms.

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