Container gantry crane

The rail type container gantry crane consists of a main beam, rigid and flexible door legs, a running trolley, a lifting mechanism, a large vehicle running mechanism, an electrical system, and an operating cab. According to the yard operation process, overhanging the cantilever in the direction of single or double door legs becomes a single or double cantilever model, while not overhanging becomes a non cantilever model. According to the site, container storage and transportation process, and loading and unloading vehicles (container trucks or railway vehicles), different structural forms such as no cantilever, single cantilever, and double cantilever are determined.

Rail mounted container gantry cranes are divided into different forms based on the structure of the main beam and door legs, as well as the anti roll devices used.

(1) The double cantilever track container gantry crane requires the container to pass through the inner space of the two side door legs. So the width direction clearance inside the door legs is relatively large. Depending on the form of the main beam carried by the door legs, double cantilever rail container gantry cranes generally adopt a "U" shape with the upper part of the door legs open and a "π" shape with the upper part of the door legs connected. The structure of the cantilevered track type container gantry crane is relatively simple because the container does not need to pass through the space inside the door legs.

(2) Compared to shore mounted container cranes, rail mounted container gantry cranes have lower trolley speeds and generally do not have anti roll devices. If users request to reduce operational intensity and improve productivity, anti roll devices are installed. For rope type lifting mechanisms, roll reduction is generally achieved by applying damping to the ropes; For rigid lifting mechanisms, roll reduction is achieved through rigid components. Rail mounted container gantry crane

Rail mounted container gantry cranes are mainly used for container loading, unloading, handling, and stacking in container railway transfer yards and large container storage and transportation yards.

The rail type container gantry crane consists of a main beam, rigid and flexible door legs, a running trolley, a lifting mechanism, a large vehicle running mechanism, an electrical system, and an operating cab. According to the yard operation process, overhanging the cantilever in the direction of single or double door legs becomes a single or double cantilever model, while not overhanging becomes a non cantilever model. According to the site, container storage and transportation process, and loading and unloading vehicles (container trucks or railway vehicles), different structural forms such as no cantilever, single cantilever, and double cantilever are determined.

Rail mounted container gantry cranes are divided into different forms based on the structure of the main beam and door legs, as well as the anti roll devices used.

(1) The double cantilever track container gantry crane requires the container to pass through the inner space of the two side door legs. So the width direction clearance inside the door legs is relatively large. Depending on the form of the main beam carried by the door legs, double cantilever rail container gantry cranes generally adopt a "U" shape with the upper part of the door legs open and a "π" shape with the upper part of the door legs connected. The structure of the cantilevered track type container gantry crane is relatively simple because the container does not need to pass through the space inside the door legs.

(2) Compared to shore mounted container cranes, rail mounted container gantry cranes have lower trolley speeds and generally do not have anti roll devices. If users request to reduce operational intensity and improve productivity, anti roll devices are installed. For rope type lifting mechanisms, roll reduction is generally achieved by applying damping to the ropes; For rigid lifting mechanisms, roll reduction is achieved through rigid components.

Characteristics:

The rail type container gantry crane mainly has the following characteristics:

① The lifting speed is low while the running speed of the large vehicle is high. According to the requirements of the container yard, the lifting height of the track type container gantry crane is determined by stacking three to four or stacking four to five. Due to the low lifting height, the lifting speed is correspondingly lower. However, container yards generally have a longer length along the running track direction, and in order to achieve a certain level of productivity, the speed of large vehicles is relatively high.

② The running speed of the car can be determined based on the span of the bridge and the outward extension distance at both ends. When the span and cantilever length are small, the operating speed and productivity requirements of the trolley can be relatively small. When the span is large and the cantilever length is also large, the running speed of the trolley can be correspondingly increased to meet productivity requirements.

③ When the span exceeds 40m, during the high-speed operation of the large vehicle, there will be displacement due to the different running resistance of the door legs on both sides. Therefore, a synchronization device is set up to maintain the synchronization of the running speed of the running mechanisms on both sides through an electrical control system.

④ To meet higher usage requirements, the electrical drive control system adopts thyristor DC or AC speed regulation control system to achieve better speed regulation and control performance. The electrical control system can also adopt conventional AC eddy current speed control or AC stator voltage regulation speed control drive control system. For the electrical control system of high-speed large vehicle operating mechanisms, thyristor DC and AC speed control systems with electrical braking or AC stator voltage regulation speed control systems are usually used to avoid the use of conventional electrical drive systems that rely on brake braking during operation and parking, in order to avoid causing significant impact to the entire machine.

Metal structure:

The steel structure of track type container gantry cranes generally adopts box structure. To reduce the overall weight of the machine, truss structure can also be used, but the production cost is relatively high.

The overall structure of the machine often adopts "π" and "U" shapes depending on the support method of the door legs. The rigid and flexible door legs of the "π" structure are both in the form of "π". The lateral stiffness of the two main beams and the strength and stiffness of the door legs themselves are achieved through the stiffness of the door legs and the crossbeam on the door legs. The U-shaped structure of the door leg is achieved through the connection stiffness between the door leg and the lower crossbeam of the door leg.

(1) Main beam structure. The main beam structure consists of two box shaped end beams supported by rigid and flexible legs. At present, skewed track box girders are commonly used. In order to avoid high stress areas caused by wheel pressure on the flange welds, the rail bearing part is welded with "T" steel to the main beam panel and load-bearing web plate. The main beam is connected to the rigid leg using high-strength bolts or welding methods, and to the flexible leg using hinged connections. For ease of installation, the connection between the main beam and the end beam is generally made using high-strength bolt connections.

(2) Door leg structure. Both rigid and flexible door legs adopt box shaped structures, and for small and medium span rail type container gantry cranes, both sides of the door legs are made into rigid door legs. For the "π" - shaped door legs, the strength and stiffness along the direction of the large vehicle are achieved through the rigid connection between the door legs and the top crossbeam; for the "U" - shaped door legs, they are achieved through the rigid connection between the door legs and the bottom crossbeam, while the strength and stiffness along the direction of the small vehicle are achieved through the rigid connection between the main beam and the rigid door legs. For small and medium span rail mounted container gantry cranes, the tilting force on the door legs and main beams caused by the unsynchronized large vehicles on both sides is borne by the rigid and single degree of freedom hinge connections between the main beams and the rigid and flexible legs.