Double Girder Electric Hoist Overhead Crane

Lifting Capacity:	5t to 32t
Span:	7.5m-31.5m
Lifting Height:	6m to 30m
Lifting Speed:	7m/min,8m/min,3.5m/min,2.4m/min
Traveling Speed:	20m/min
Working Class:	M4
Ambient Temperature:	-20℃ to 40℃

 

Double Girder Electric Hoist Overhead Crane also known as electric hoist bridge crane or electric hoist double beam crane. The applicable lifting capacity range of this crane is between 5-32 tons, the span range of the two end beams of the crane is between 7.5 and 31.5 meters, and the normal working environment temperature is -20~+40 ℃. The LH type electric hoist bridge crane has the characteristics of light weight, small size, simple structure, and economic practicality. It mainly consists of three parts: metal structure, operating mechanism, and electrical equipment. Suitable for transportation, assembly, maintenance, and loading and unloading operations in mechanical processing workshops, metallurgical plant auxiliary workshops, warehouses, material yards, power stations, etc.

 

 

The LH type electric hoist bridge crane is designed according to GB3811-2008 and JB/T3695-2008 standards. It is a workshop lifting equipment that uses A2 fixed electric hoists such as CD1, MD1, WH164 as lifting mechanisms. It is widely used in mechanical processing workshops, metallurgical plant auxiliary workshops, warehouses, material yards, power stations, and other transportation, assembly, maintenance, and loading and unloading operations; It can also replace ordinary double beam bridge cranes and be used in production workshops of the textile and food industries. It is an important tool and equipment for modern industrial enterprises to achieve mechanization and automation of production processes, reduce heavy physical labor, and improve labor productivity.

 

This product has the advantages of compact structure, good rigidity, easy operation, low noise, low building clearance height, light weight, low wheel pressure, safety and reliability, and beautiful appearance. The main components include: electronic control system, trolley, crane, and bridge frame.

Four wheels on one side, connected by a flexible wheel in the middle, eliminate phenomena such as three legs, rail gnawing, and deviation, ensuring even wheel pressure and smooth operation.

 

Bridge frame:

The bridge mainly consists of main beams, end beams, walkways, conductive supports, trolley tracks, walkways, railings and other components. The bridge adopts a double beam structure, which has sufficient strength, stiffness, and overall stability.

The materials used for the main structural components (main beam, end beam, and trolley frame) shall comply with the provisions of GB/T14405-93 and meet the requirements of GB700. The surface treatment of steel structures shall meet the grade Sa21/2 specified in GB8923.

Main beam:

The main beam is an important load-bearing structural component of the crane, and this series of cranes adopts a skewed track box beam. Each main beam is manufactured strictly according to our company's box girder manufacturing process standards from drop to welding. The main beam is made of Q235B material, and all steel plates are rolled, leveled, shot blasted, rust removed, and then sprayed with weldable primer before cutting. Prefabricate the upper camber when cutting the web plate. The arch degree of the completed main beam shall be ensured to be 0.9S/1000-1.4S/1000 (S is the span of the crane). The maximum camber value is controlled within the range of S/10 at the mid span. There is a complete track for the operation of the trolley in the middle of the upper cover plate, and the track is welded to make it a whole. The joints are polished flat to ensure the good operation of the trolley. The design of the main beam fully meets the requirements of strength, stiffness, and stability.

End beam:

The end beam device, also known as the crossbeam, is made of rectangular tubes and made of Q235B material. It is located at both ends of the main beam and connected to the end beam bolts through the main end beam connection plate. Hand holes are provided on both sides of the middle connection plate of the crossbeam for easy disassembly and installation of the main end beam. Polyurethane buffers are installed at both ends of the end beam to prevent damage to structural components due to collisions. The positioning pin axis is used between the main and end beams, which improves installation accuracy, has a simple structure, is easy to install, and is convenient for transportation and storage. It has the characteristics of lightweight structure, good rigidity, and beautiful appearance.

Trolley frame:

The main structural components of the trolley frame are made of Q235B material, and the trolley frame adopts a six beam structure consisting of two end beams, two longitudinal beams, and two transverse beams.

The end beam of the car is made of rectangular tubes, and the longitudinal and transverse beams are respectively made of channel steel, I-beam or rectangular tubes according to the tonnage and lifting height. Under rated load, its static deflection trolley S/2000 (S is the track gauge of the trolley) ensures sufficient strength and stiffness to ensure the smooth operation of the mechanism.

Hoisting mechanism:

Using CD, MD or WH type A2 fixed high-quality steel wire rope electric hoist as the lifting mechanism. The lifting mechanism is driven by the lifting motor through the coupling and the hollow shaft of the reducer to rotate the drum, so that the steel wire rope wound on the drum drives the hook device to rise or fall.

Electric hoist is mainly composed of components such as electric motor, reducer, drum, hook assembly, pulley assembly, etc.

 

Operating mechanism:

Trolley operating mechanism:

The running mechanism of the trolley consists of a three in one drive device, a wheel set, etc;

The trolley series adopts a three in one drive device, which integrates a soft start motor, reducer, and brake, thereby improving the quality of on-site installation, shortening assembly time, and optimizing on-site installation procedures. The integrated feature of the driver is small in size, light in weight, easy to install, and compact in structure.

The wheel set is made of 45 # steel, which is processed through rough turning, quenching, tempering, and precision turning. The heat treatment hardness is 300-380HB, and the depth of the quenched layer is not less than 260HB at 15mm. The wheel shaft material is 45 # steel, which is processed through rough turning, quenching and tempering, and precision turning, with a heat treatment hardness of 235-269HB.

Crane operating mechanism:

The crane operating mechanism consists of a three in one drive device, a wheel set, etc;

The crane series adopts a three in one drive device, which integrates a soft start motor, reducer, and brake, thereby improving the quality of on-site installation, shortening assembly time, and optimizing on-site installation procedures. The integrated feature of the driver is small in size, light in weight, easy to install, and compact in structure.

The wheel set is made of 45 # steel, which is processed through rough turning, quenching, tempering, and precision turning. The hardness of the heat treatment is 300-380HB, and the depth of the quenched layer is not less than 260HB at 15mm. The wheel shaft material is made of 45 # steel, which is processed through rough turning, quenching and tempering, and precision turning, and the hardness of the heat treatment is 235-269HB. The wheels are equipped with track sweepers and buffers.

The crane operating mechanism adopts dual drive or four-wheel drive separate driving devices, which have stable operation, light weight, good universality, easy installation and maintenance, and the operating performance is not affected by bridge deformation during lifting. Separate driving also has the advantages of reducing the wear and tear caused by wheel tilting and deviation, and reducing the risk of wheel climbing and falling off the track

 

Electric control system:

Power supply

The standard power supply for the crane is a three-phase 380V (± 10%, with a lower limit of -15% during peak current), 50Hz electrical control system.

Power supply method

The slides used for feeding soft cables and cable pulleys can be angle steel slides or special-shaped steel slides.

Electrical control mode

• Direct control mode: The direct control mode means that the motor is directly controlled by contactor, which can achieve single and dual speed, forward and reverse control of the motor.

Control method:

• Ground operation: Press the buttons on the handle to control the movements of various mechanisms of the crane.
• Remote control operation: The corresponding mechanism of the crane is controlled by an industrial remote control.

In addition, the crane can also be equipped with two sets of operating devices, namely ground+remote control operation. The two operating modes can only be switched and cannot be used simultaneously. The control circuit voltage is generally 36V safe voltage.

 

Electrical protection system

Short circuit protection

The main power circuit is equipped with an automatic air switch as a short-circuit protection for the crane; The control circuit is equipped with a small capacity automatic air switch as short-circuit protection.

Voltage loss protection

The circuit structure has a voltage loss protection function, and when power is restored after a power outage, the crane must press the start button again to resume operation, eliminating the possibility of self operation of the crane when powered on.

Emergency power-off switch

The crane is equipped with a red mushroom shaped rotating reset emergency power-off switch, which is used to quickly cut off the main power supply and control circuit of the crane in emergency situations. The emergency power-off switch is installed in a convenient location for personnel to operate.

Overload limiter

When the load reaches 90% of the rated lifting capacity, the overload limiter emits a warning signal. When the load reaches 110% of the rated lifting capacity, the lifting power supply is immediately cut off and a prohibition alarm signal is issued. The sensor of the overload limiter has the characteristics of moisture resistance and earthquake resistance. The sensor is integrated with the control box, reducing the interference of the sensor signal.

Travel limit

The lifting mechanism is equipped with a rising and falling cut-off limit switch, which serves as a limit switch for the lifting range of the lifting mechanism and also has a protective effect against controller adhesion.

The vehicle mechanism is equipped with an operating limit limiter. It consists of a travel limit switch and a safety ruler. The travel limit switch is installed on the crane, and the safety ruler is installed on the rail beam or wall where it does not hinder the operation of the crane, ensuring that the crane operates within a safe range. The limit limiters for both large and small vehicles can be ordinary limit switches.

Phase failure, phase mismatch, overvoltage, undervoltage protection

The comprehensive protector in the crane circuit system has protection functions for phase failure, phase mismatch, overvoltage, and undervoltage. When these four situations occur, it will automatically cut off the main power supply of the crane to prevent personnel injury and equipment damage.

Grounding protect

The metal structures on the crane and all electrical equipment metal shells and pipe troughs, as well as the low-voltage side of the transformer, are reliably grounded with a total grounding resistance of ≤ 4 Ω. It is allowed to use the crane's track as a grounding wire. The insulation resistance of the crane to the ground at room temperature shall not be less than 1M Ω (this value is measured by a 500V megohmmeter at room temperature).

 

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