Truss Gantry Crane: Lifting Mechanism

Truss gantry cranes, commonly known as gantry cranes, are large lifting equipments widely used in ports, shipyards, heavy industry, logistics centers and other places. 

Although the truss gantry crane belongs to the gantry crane, it has undergone a great defense in structure, which also makes the truss gantry crane have a stronger carrying capacity and has a higher working efficiency in use. Now, let's focus on the lifting mechanism of the truss gantry crane.

Lifting mechanism introduction

As an important component of the truss gantry, the lifting mechanism is mainly composed of a large torque bidirectional hydraulic motor and a winch, and the motor drives the winch to lift the heavy object. Since the speed of the hydraulic motor can be adjusted by changing the engine speed, the lifting hydraulic circuit of the truss gantry crane is a balance circuit, and the balance valve is composed of an improved external control sequence valve and a one-way valve.

It is precisely because the truss gantry crane uses a balance valve that the heavy object will not stop and start when it is lowered. When the reversing valve core is changed to the right position, the pressure oil enters the hydraulic motor through the one-way valve of the balance valve to lift the heavy object. When the reversing valve core is changed to the left position, the pressure oil directly enters the hydraulic motor; the balance valve is opened, and the hydraulic motor oil return chamber returns oil through the balance valve, and the heavy object falls steadily.

When the reversing valve in the truss gantry crane is switched back to the middle position, the balance valve is closed, the hydraulic motor stops, and the heavy object stops in the air. However, since the leakage of the hydraulic motor is much larger than that of the hydraulic cylinder, the heavy object still slips in the air despite the good sealing of the balance valve.

In order to avoid similar phenomena, the truss gantry crane is equipped with a brake cylinder on the hydraulic motor. When the reversing valve core is switched back to the middle position to stop the hydraulic motor, the oil in the rod chamber of the brake cylinder returns through the one-way valve of the throttle valve, so that the hydraulic motor brakes quickly and the heavy object stops falling quickly.

When the reversing valve core is switched back to the right position to make the heavy object rise again, the pressure oil slowly flows into the rod chamber of the brake cylinder through the throttle valve of the throttle valve, so that the brake cylinder slowly loosens, so as to avoid the heavy object in the truss gantry crane from sliding down due to its own weight.

truss double girder gantry cranes

usage characteristics and advantages

The main structure of the truss gantry crane includes two supporting legs (columns), a beam (crossbeam) spanning the two supporting legs, and a lifting trolley that can move on the crossbeam. This structural form allows it to carry out material handling in a larger range.

According to the frequency of use and load conditions, the truss gantry crane is divided into different working levels, such as light working level (A3-A4), medium working level (A5) and heavy working level (A6-A7). 

Modern truss gantry cranes usually use remote control or automatic control systems to improve the safety and efficiency of operation.

Many truss gantry cranes are designed with tracks and can move on the tracks, increasing the working range and flexibility.

Truss gantry cranes can carry very heavy cargoes, and the lifting capacity can reach hundreds of tons or even thousands of tons.

According to needs, the truss gantry crane can be designed with a large span, which is suitable for material handling in a wide field.

The lifting trolley of the gantry crane can move quickly on the crossbeam, greatly improving the handling efficiency. 

Whether indoors or outdoors, ports or factories, flower-frame gantry cranes can adapt to different working environments.

Conclusion

Due to their unique structure and multiple advantages, flower-frame gantry cranes play an indispensable role in the industrial and logistics fields. With the development of technology, the functions and efficiency of these lifting equipment are also constantly improving, better meeting the needs of modern industrial production. 

If you want to know more about truss gantry cranes, here is "Introduction to Truss Type Electric Gantry Crane".