Abstract:
Embodiments of the present invention include quayside cranes and yard cranes related by a low elevated transfer system and a ground transportation carrier system. The low elevated transfer system includes low elevated transfer subsystems having low elevated rails, the low elevates rails include low elevated crane rails and low elevated flat carrier rails, low elevated cranes are disposed on the low elevated crane rails and low elevated flat carriers are disposed on the low elevated flat carrier rail. The ground transportation carrier system includes ground transportation carrier rails and transportation carriers moving along the ground transportation carrier rails. Embodiments of the present invention transport the containers by rails and use municipal electric as the power supply. A three-dimensional low elevated transfer system and a ground transportation carrier system are provided to implement three-dimensional transportation of containers. Embodiments of the present invention provide a container transportation schema that is efficient, power saving, environmental and automatic, ground resources are utilized with high efficiency. The present invention is an expansion and development of the invention provided in CN 200510111464.0.

Description:
FIELD OF THE INVENTION 
       [0001]    Embodiments of the present invention relates to container loading/unloading technique for a container terminal, more particularly, relates to a loading/unloading system for efficiently transfer a container between a certain position on a ship and a certain position on a terminal. 
       BACKGROUND 
       [0002]    With the blooming demand for container transportation all over the world and the growth in throughput of container terminals, requirements on container loading/unloading device and process is also improved. There is a need for a new container loading/unloading device and system that has higher efficiency, so as to meet the requirements on loading/unloading production efficiency of a terminal for a scaled, speed and automatic transportation of containers. 
         [0003]    From 1990s, with the development of the world economic and trade, the amount of transportation of containers increases, new techniques, especially automatic control techniques of quayside container cranes develop quickly. However, loading/unloading systems that are currently used for a container terminal still have the following problems. 
         [0004]    Generally, a container terminal may be divided into a front area (a quayside area) and a rear area (a yard area) and a middle area. Quayside cranes located in the front area load/unload containers with a container ship, a yard at the rear area is used to stack containers. Trucks are used to transport containers between the front area and the rear area. 
         [0005]    For transportation between the quayside cranes and the yard, nowadays, plane trucks driven by diesel engine are used to achieve transportation between a front area and a rear area. For an unloading process, the quayside cranes unload containers from a ship to the plane trucks, the plane trucks transport the containers to a yard, then yard cranes hoist the containers from the plane trucks and put them on the yard. For a loading process, the yard cranes hoist containers from the yard and put them on plane trucks, the plane trucks transport the containers to a position below the quayside cranes, the quayside cranes load the containers to the ship. Attempts are made for an automatic loading/unloading process for containers, for example, Port of Rotterdam in Netherlands and Hamburger Harbor in Deutschland introduce Automatic Guided Vehicles (AVG) to replace the plane trucks driven by drivers. AGVs are still driven by diesel engine, there is no improvement in energy source. Additionally, AGVs are very expensive, and must move along a single guide line which is buried in advance in a same plane. If one of the AGVs is failed, the whole system is stopped. Unfortunately, failure possibility of AGVs is very high because of the complex structure, failures of AGVs are also difficult to deal with. Therefore, the current attempts of automatic systems face a low efficiency and a high cost. 
         [0006]    Whatever the traditional manual manner, or the automatic attempts, the loading/unloading mode of containers can be concluded as: a plane transportation mode consists of quayside cranes located at a quayside area of a container terminal, yard cranes located at a yard area of the container terminal, and diesel engine driven vehicles, such as container trucks, cross transportation trucks, AGVs moving between the quayside cranes and the yard cranes for transporting the containers. The loading/unloading mode needs dozens or even hundreds of diesel engine driven vehicles, for ensuring a smooth movement of these vehicles, a large space must be reserved between the quayside and the yard, which occupies a considerable size of ground. Even a large space is provided, the traffic within the container terminal is still very crowd because all of the vehicles move in a same plane. The vehicles work in a low efficiency, not being able to timely transport containers, and decrease the loading/unloading efficiency of the whole container terminal. Efficiency of vehicles becomes a bottle-neck of loading/unloading efficiency of the container terminal. Furthermore, oil is expensive, operation cost of the container terminal is high and benefit of the container terminal is getting lower. Another problem is, burning oil produces a large amount of exhaust gas and noise, seriously pollute the environment. Maintenance fee of the diesel engine driven vehicles is also very high. The plane transportation technique falls behind, and can not facilitate infomationization, automation and intelligentization of the container terminal. 
       SUMMARY 
       [0007]    Embodiments of the present invention provide a new loading/unloading system for container terminal, by using the new system, traditional plane transportation mode is changed to be a three-dimensional transportation mode, diesel engines are replaced with electric power supply, rails are also provided to guide the transportation. Embodiments of the present invention achieve an automatic transportation process of loading/unloading, transferring and stacking containers, which is high efficient, power saving, speedy, accurate and environmental. 
         [0008]    Embodiments of the present invention provide a new loading/unloading system for container terminal, including a three-dimensional low elevated transfer system located between quayside cranes and yard cranes, and cooperating with a ground transportation carrier system. The low elevated transfer system includes at least one low elevated transfer subsystem, each subsystem includes at least one group of low elevated rails disposed along a first direction. Each group of low elevated rails includes a low elevated crane rail and a low elevated flat carrier rail. At least one low elevated crane is disposed on the low elevated crane rail and moves along the low elevated crane rail, at least one low elevated flat carrier is disposed on the low elevated flat carrier rail and moves along the low elevated flat carrier rail. The low elevated rails are configured to enable the low elevated flat carriers and the low elevated cranes to reach at least a position where the low elevated cranes can cooperate with trolleys of the quayside cranes and a position where the low elevated cranes can cooperate with the ground transportation carriers. The low elevated cranes may load/unload containers on/off a low elevated flat carrier and a corresponding ground transportation carrier ay any necessary place. The low elevated place carriers may move to a certain position associated with a certain quayside crane and a certain position associated with a certain ground transportation carrier. The ground transportation carrier system includes at least a group of transportation carrier rails disposed along a second direction, which align to passages in the yard and extend to a necessary position in the yard. The transportation carrier rails also extend to a position below the lowest tier of the low elevated transfer subsystem in the low elevated transfer system. The ground transportation carrier system further includes ground transportation carriers moving along the ground transportation carrier rails. The ground transportation carrier rails are configured to enable the ground transportation carriers to reach at least a position where the ground transportation carriers can cooperate with the low elevated cranes and a position where the ground transportation carriers can cooperate with the yard cranes. The ground transportation carrier rails are further configured to ensure that the ground transportation carriers are not in the same plane with any low elevated flat carriers on any tier of the low elevated transfer system. One of ground transportation carrier or the low elevated crane has an ability to rotate to an angle between the first direction and the second direction with or without a container. The ground transportation carrier rails may be configured to extend to an end of the yard rather than entering into the yard, or be configured to extend into a deep position in the yard or extend though the yard. 
         [0009]    In a loading process, a yard crane hoists a container in the second direction from a yard, the yard crane moves to a position above a ground transportation carrier along a yard crane rail or the ground transportation carrier moves to a position below the yard crane along a ground transportation carrier rail, the yard crane puts the container onto the ground transportation carrier and the ground transportation carrier moves along the ground transportation carrier rail to a position below a low elevated rail of the low elevated transfer system, the round transportation carrier or a low elevated crane rotates the container from the second direction to the first direction, the low elevated crane hoists the container from the ground transportation carrier to a low elevated flat carrier, the low elevated flat carrier moves along the low elevated flat carrier rail to a position below a quayside crane, the quayside crane hoists the container from the low elevated flat carrier to the ship. In a unloading process, a quayside crane hoists a container in the first direction from a ship and puts the container onto a low elevated flat carrier, the low elevate flat carrier moves along a low elevated flat carrier rail to a position that can cooperate with a ground transportation carrier, a low elevated crane hoists the container to a ground transportation carrier, the low elevated crane or the ground transportation carrier rotates the container from the first direction to the second direction, the ground transportation carrier moves along a ground transportation carrier rail to a yard, a yard crane hoists the container from the ground transportation carrier to the yard. 
         [0010]    Embodiments of the present invention implement a railed transportation that uses municipal electricity as power supply, thus the problems such as pollution (exhaust gas and noise) caused by diesel engine driven vehicles (trucks, AGVs, cross-transportation vehicles) can be solved. Embodiments of the present inventions provide a better profit for the container terminals, and facilitate informationization, automation and intelligentization of the container terminals. The three-dimensional low elevated transfer system and the ground transportation carrier system used in embodiments of the present invention also overcome the drawbacks such as low efficiency and poor safety of the traditional plane transportation system, the speed and efficiency of transportation between the quayside cranes and the yard cranes are greatly increased. Furthermore, the three-dimensional low elevated transfer system reduces the distance considerably between the quayside cranes and the yard cranes, so that more space can be used to stack containers and the ground is sufficiently utilized. Rotation of the containers is solve by using a rotatable transportation carrier or a rotatable low elevated crane. A whole schema of the present invention is proper for an automatic container terminal. Embodiments of the present invention have an advantage of high load/unload efficiency, and provide a new production mode for load/unload process of a container terminal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
         [0011]    The above or other features, natures or advantages of the present invention will be more apparent to the skilled person in the art by the following descriptions of the embodiments accompanying with the drawings, the same sign reference indicates the identical features throughout the description, and wherein: 
           [0012]      FIG. 1   a  is a top view of a loading/unloading system according to a first embodiment of the present invention; 
           [0013]      FIG. 1   b  is a side view of  FIG. 1   a;    
           [0014]      FIG. 2   a  is a structural diagram of a quayside crane according to an embodiment of the present invention; 
           [0015]      FIG. 2   b  is a side view of  FIG. 2   a;    
           [0016]      FIG. 3   a  is a structural diagram of the structure of a low elevated transfer subsystem in a low elevated transfer system according to an embodiment of the present invention; 
           [0017]      FIG. 3   b  is a side view of  FIG. 3   a;    
           [0018]      FIG. 3   c  is a structural diagram of a multi-tier low elevated transfer system according to an embodiment of the present invention; 
           [0019]      FIG. 3   d  is a side view of  FIG. 3   c , which illustrates two low elevated transfer subsystems with two tiers of low elevated rails; 
           [0020]      FIG. 4   a  is a structural diagram of a ground transportation carrier in a ground transportation carrier system according to an embodiment of the present invention; 
           [0021]      FIG. 4   b  is a side view of  FIG. 4   a;    
           [0022]      FIG. 5   a  is a structural diagram of a yard crane according to an embodiment of the present invention; 
           [0023]      FIG. 5   b  is a side view of  FIG. 5   a;    
           [0024]      FIG. 6   a  is a structural diagram of a low elevated crane according to an embodiment of the present invention; 
           [0025]      FIG. 6   b  is a side view of  FIG. 6   a;    
           [0026]      FIG. 6   c  is a side view of  FIG. 6   c  from another perspective. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Main concept of embodiments of the present invention is to provide a three-dimensional low elevated transfer system and a ground transportation system between quayside cranes and yard cranes, utilize electric driven flat carriers (including low elevated flat carriers and ground transportation carriers) being disposed on rails with different height and moving there along and cranes (low elevated cranes) working between the rails with different height to realize transportation of containers between a certain place on a ship and a certain place in a yard. The electric driven flat carriers can move along the rails in both directions and transport the containers from one end to the other end. A rotation platform on the ground transportation carrier or a rotation mechanism on the low elevated crane can rotate clockwise or counterclockwise with or without the container, thus the containers may be arranged in different directions in the ship and in the yard. 
         [0028]    Based on the above concept, embodiments of the present invention provide a low elevated transfer system, a ground transportation carrier system, and also provide quayside cranes and yard cranes that are connected by the low elevated transfer system and the ground transportation carrier system, so as to implement high efficient transportation of containers. 
         [0029]    In the following descriptions, for the purpose of clarity, a first direction refers to a direction that the containers are arranged in a ship, a second direction refers to a direction that the containers are arranged in a yard, the first direction is perpendicular to the second direction. 
         [0030]    Loading/Unloading System for Container Terminal 
         [0031]    Embodiments of the present invention provide a loading/unloading system for a container terminal in which containers are arranged in perpendicular directions in a ship and in a yard. Referring to  FIGS. 1   a  and  1   b , a first schema of the loading/unloading system for a container terminal is shown. 
         [0032]    The system includes a plurality of quayside cranes  100 . A quayside crane  100  includes at least a travelling mechanism  101 , a trolley  102 , and a hoisting mechanism  103 . The quayside crane  100  is operable for loading/unloading containers on/off a ship, and loading/unloading containers on/off a low elevated transfer system  200 . The containers in the ship are arranged in the first direction and the containers hoisted by the quayside crane  100  are kept in the first direction. The trolley  102  on the quayside crane  100  moves along the second direction, which is perpendicular to the first direction. It should be noted that a rail of the trolley  120  extends to a position over low elevated rails  202  of the low elevated transfer system  200  and covers all of the low elevated rails  202 , so that the trolley  102  can load/unload of containers on/off any low elevated flat carriers  206  of the low elevated transfer system  200 .  FIGS. 1   a  and  1   b  illustrate a quayside crane  100  having a single trolley for hoisting two 40 feet containers as an example. For a quayside crane having two trolleys, the present invention may be realized through a reasonable arrangement of the rails of the two trolleys, which can be forecasted by one of the ordinary skilled in the art. 
         [0033]    The system also includes a low elevated transfer system  200  (which will be further described in detail below). The low elevated transfer system  200  includes at least one low elevated transfer subsystem. Each low elevated transfer subsystem has a low elevated structure  202  and supports  201 . At least one group of low elevated flat carrier rails  203  is disposed along the first direction, and at least one low elevated flat carrier  206  is disposed on each group of the low elevated flat carrier rails  203  and moves there along. At least one group of low elevated crane rails  204  is disposed along the first direction, and at least one low elevated crane  205  is disposed on each group of the low elevated crane rails  204 . The low elevated crane  205  loads/unloads containers on/off the low elevated flat carrier  206  and ground transportation carrier  301 . The low elevated flat carrier rails are configured to enable the low elevated flat carriers  206  to reach at least a position where the low elevated flat carriers  206  can cooperate with the trolley  102  of the quayside crane  100  and a position where the low elevated flat carriers  206  can cooperate with the ground transportation carrier  301 . Scale of the low elevated transfer system  200 , that is, the number of the low elevated transfer subsystems is determined based on the number of berths in the container terminal, the number of quayside cranes and the number of yards. On each group of low elevated crane rails  204 , one or two low elevated cranes  205  may be provided, the low elevated cranes  205  move in both directions along the low elevated crane rails  204 . Similarly, on each group of low elevated flat carrier rails  203 , one or two low elevated flat carriers  206  may be provided. When two low elevated flat carriers  206  are provided on each group of low elevated flat carrier rails  203 , the two low elevated flat carriers  206  are used for transportation of containers in a left side and a right side of the quayside crane  100  respectively. According to embodiments of the present invention, a plurality of low elevated structures can be stacked (which will be described in detail below). The low elevated flat carriers  206  and the low elevated cranes  205  may move along the low elevated flat carrier rails  203  and the low elevated crane rails  204 , which are disposed in the first direction to a position that is desired. It should be noted that, all of the low elevated cranes  205  and low elevated flat carriers  206  shall be arranged in a position that can be reached by the trolley  102  of the quayside crane. That is, all of the low elevated cranes  205  and low elevated flat carriers  206  shall be arranged in an area below the rail of the trolley  102  of the quayside crane and above the ground transportation rails of the ground transportation carrier  301 . In an embodiment, the low elevated transfer system  200  further includes a backup low elevated transfer subsystem. When the load/unload operation is busy, or a yard is so far away that the transportation speed of the low elevated transfer system and the ground transportation carrier system can not keep up with the loading/unloading speed of the quayside cranes, or one of the low elevated transfer subsystem is failed, the backup low elevated transfer subsystem can be used to maintain the production efficiency of the whole container terminal. 
         [0034]    The loading/unloading system further includes a ground transportation carrier system  300 . The ground transportation carrier system  300  includes at least one group of ground transportation carrier rails  302 . The ground transportation carrier rails  302  align to passages of the yard and extend to a desired position in the yard (according to the illustrated embodiment, two groups of ground transportation carrier rails are provided, one group extends through the yard and the other ground extends into the yard). The ground transportation carrier rails  302  also extend to a position below the lowest tier of the low elevated structure (if a multi-tier low frame structure is provided) in the low elevated transfer system  200 . The ground transportation carrier system  300  further includes a ground transportation carrier  301  moving along the ground transportation carrier rails  302 . According to an embodiment of the present invention, one of the ground transportation carrier  301  or the low elevated crane  205  has an ability to rotate to an angle between the first direction and the second direction with or without a container. According to an embodiment, the low elevated crane  205  performs the 90° rotation. In an implementation, it would be sufficient when one of the two devices had the ability to rotate. If a low elevated crane  205  that has the ability to rotate is used, then the ground transportation carrier  301  may not need the rotation ability. Similarly, if a low elevated crane  205  that does not have the ability to rotate is used, the ground transportation carrier  301  may rotate the container which is carried by it. Structure of the ground transportation carrier  301  will be described in detail below. The ground transportation carrier rails  302  are configured to enable the ground transportation carriers  301  to reach at least a position where the ground transportation carriers  301  can cooperate with the low elevated cranes  205  and a position where the ground transportation carriers  301  can cooperate with the yard cranes  400 . The ground transportation carrier rails  302  are further configured to ensure that the ground transportation carriers  301  are not in the same plane with any low elevated flat carriers on any tier of the low elevated transfer system  200  so as to avoid a collision between the ground transportation carriers  301  and the low elevated flat carriers  206 . The ground transportation carrier system  300  establishes a connection between the low elevated transfer system  200  and the yards. 
         [0035]    In a loading process, a yard crane  400  hoists a container and puts it onto a ground transportation carrier  301 . The yard crane  400  may move to a position above a ground transportation carrier  301  along a yard crane rail, or the ground transportation carrier  301  may move to a position below the yard crane  400  along a ground transportation carrier rail  302  (it is preferred that the ground transportation carrier  301  rather than the yard crane  400  moves, so as to avoid a movement of the large yard crane  400  with the containers). In an embodiment, one group of the ground transportation carrier rails extend through the yard and another group of ground transportation carrier rails extend into the yard. After the yard crane  400  puts the container onto the ground transportation carrier  301 , the ground transportation carrier  301  moves along the ground transportation carrier rails  302  to a position below the low elevated transfer system  200 . The containers in the low elevated transfer system  200  are in the first direction, that is, the direction of the container in the low elevated transfer system  200  is different with the direction of the containers on the ground transportation carrier  301  (in an embodiment, a difference is 90°). The ground transportation carrier  301  rotates 90° with the container and then the low elevated crane  205  hoists the container. According to an embodiment, the ground transportation carrier  301  does not rotates and the low elevated crane  205  rotates 90° during the hoisting process, either in clockwise or counterclockwise so as to make the container to be in the first direction. Then the low elevated crane  205  hoists the container from the ground transportation carrier to the low elevated flat carrier  206 , the low elevated flat carrier  206  moves along the low elevated flat carrier rail  203  to a position below the quayside crane. The quayside crane hoists the container from the low elevated flat carrier to the ship. 
         [0036]    For the unloading process, just perform the above process in a reverse order and will not be described in detail here. It should be noted that the yard crane  400  has a travelling mechanism  401  moving along the second direction, a trolley  402  moving along a direction perpendicular to the second direction and a hoisting mechanism  403  moving in a vertical direction. The containers are arranged in a second direction in the yard. The travelling mechanism  401  of the yard crane  400  enables the yard crane to move to at least a position that can connect with the ground transportation carrier  301  and a desired position in the yard. In an embodiment, when the ground transportation carrier rails  302  extend to the passages in the yard and go through the yard, the transportation of containers between the yard and the ground transportation carrier system is mainly achieved by the ground transportation carriers  301 . 
         [0037]    Quayside Crane 
         [0038]    For the quayside crane shown in  FIGS. 1   a  and  1   b , it could be any existent quayside crane. The quayside cranes are used to load/unload containers on/off a ship, and on/off the low elevated transfer system. The applicant of the present application has also proposed several applications on the quayside cranes, all of these quayside cranes may be applied to the whole schema of the container terminal that is provided according to the present invention. 
         [0039]    As shown in  FIGS. 2   a  and  2   b , a quayside crane for hoisting two 40 feet containers is illustrated as an example. The quayside crane  100  includes a traveling mechanism  101 , which drives the quayside crane  100  to move along the quayside. The quayside crane  100  includes a trolley  102  moving along a trolley rail to a position for loading/unloading on/off the ship and a position for loading/unloading on/off the low elevated transfer system. The quayside crane  100  further includes a hoisting mechanism  103  for loading/unloading containers at different heights. 
         [0040]    For the purpose of increasing the production efficiency and automatic level, a quayside crane having two trolleys, which is also proposed by the applicant of the present invention may also be applied to the loading/unloading system of the present invention. 
         [0041]    Furthermore, a quayside crane for simultaneously hoisting two 40 feet containers, which is also proposed by the applicant of the present invention may be applied to the loading/unloading system of the present invention. If such a quayside crane is used, the corresponding low elevated flat carriers  206 , ground transportation carriers  301 , low elevated cranes  205 , and yard cranes  400  shall also have the ability to process two 40 feet containers simultaneously, so that a best efficiency can be achieved. 
         [0042]    And, a quayside crane having two trolleys and can hoist two 40 feet containers simultaneously may also be applied to the loading/unloading system of the present invention. 
         [0043]    High efficient quayside cranes can increase the whole production efficiency of the container terminal, however, it should be noted that any existent quayside cranes or any new quayside cranes that will be developed can be applied in the loading/unloading system of the present invention. Embodiments of the present invention are focused on the whole loading/unloading system, not just a particular component, such as the quayside crane in the system. 
         [0044]    Low Elevated Transfer System 
         [0045]    The low elevated transfer system includes at least one low elevated transfer subsystem, each including at least one group of low elevated rails disposed along the first direction. Each group of the low elevated rails includes low elevated flat carrier rails and low elevated crane rails. At least one low elevated crane is disposed on and moving along one low elevated rail, at least one low elevated flat carrier is disposed on and moving along one low elevated flat carrier rail. The low elevated crane performs load/unload to a low elevated flat carrier and a corresponding ground transportation carrier, the low elevated flat carrier rails are configured to enable the low elevated flat carriers to reach at least a position where the low elevated flat carriers can cooperate with trolleys of the quayside cranes and a position where the low elevated flat carriers can cooperate with the corresponding ground transportation carriers. 
         [0046]    Referring to  FIGS. 3   a ,  3   b  and  3   c , a subsystem of the low elevated transfer system  200  is illustrated. Referring to  FIGS. 3   a  and  3   b , basic components of the low elevated structure is illustrated. A series of supports  201  are arranged with a predetermined interval. A low elevated structure  202  is disposed on the supports  201  along the first direction. Rails  203  and  204  are disposed on the low elevated structure  202 . As shown in  FIG. 3   d , a two-tier structure is shown. At least one low elevated crane is disposed on and move along each group of a low elevated crane rails  204 , and at least one low elevated flat carrier is disposed and move along each group of low elevated flat carrier rails  203  (see  FIG. 3   a ,  3   b ). The low elevated crane performs load/unload to the low elevated flat carrier  206  and to the ground transportation carrier  301 . The low elevated flat carrier rails  203  and the low elevated crane rails  204  are configured to enable the low elevated crane  205  and the low elevated flat carrier  206  to reach a position that can cooperate with the quayside cranes and a position that can cooperate with the ground transportation carriers. As mentioned above, for a large container terminal, two low elevated flat carriers  206  may be configured on each low elevated flat carrier rail  203  and two low elevated cranes  205  may be configured on each low elevated crane rail  204 . 
         [0047]    Referring to  FIGS. 3   c  and  3   d , for sufficient utilization of the space, the low elevated transfer system  200  of the present invention can be provided with a multi-tier structure. As shown in  FIG. 3   d , in the low elevated structure  202 , an upper tier low elevated flat carrier rail  203  and a lower tier low elevated flat carrier rail  203  is provided. One or two low elevated flat carriers  206  may be provided on each tier of the low elevated flat carrier rail so that the production efficiency can be further increased. 
         [0048]    Generally speaking, scale of the low elevated transfer system  200 , that is, the number of the low elevated transfer subsystem is determined based on the scale of the container terminal, including the number of berths in the container terminal, the number of quayside cranes and the number of yards. 
         [0049]    In an embodiment, the low elevated transfer system  200  further includes a backup low elevated transfer subsystem. When the load/unload operation is busy, or the low elevated cranes or low elevated flat carriers on one of the low elevated transfer subsystem are failed, the backup low elevated transfer subsystem can be used to maintain the production efficiency of the whole container terminal. 
         [0050]    Low Elevated Flat Carrier and Ground Transportation Carrier 
         [0051]    Referring to  FIGS. 4   a  and  4   b , a flat carrier according to an embodiment of the present invention is illustrated. The carrier may be used as a low elevated flat carrier  206 , or a ground transportation carrier  301 . The flat carrier  500  includes: a base  502 , a group of wheels and a driving device  504  mounted on the base  502 . The group of wheels is disposed on a group of rails and the driving device  504  drives the flat carrier  500  to move along the rails. The flat carriers of the present invention may have different driving manners, such as self-driven or traction-driven. 
         [0052]    As mentioned above, when the flat carrier is used as a ground transportation carrier  301 , it shall further have rotation ability. A rotation mechanism and a rotation plate may be provided on the flat carrier, and the rotation mechanism can rotate 90° with a container. Structure of the rotation mechanism may refer to an application with the application number 200610028895.5, which is also filed by the applicant of the present application. 
         [0053]    Ground Transportation Carrier System 
         [0054]    The ground transportation carrier system  300  of the present invention includes ground transportation carrier rails  302  except for the ground transportation carrier  301 , which is implemented by the flat carrier  500  mentioned above. The ground transportation carrier rails  302  are in the second direction, that is, parallel to the containers in the yard. According to different schemas of container terminals, the ground transportation carrier rails  302  may extend to the yard or extend through the yard, or just extend to an end of the yard. 
         [0055]    The ground transportation carrier system  300  connects the low elevated transfer system  200  and the yard. In a loading process, a yard crane  400  hoists the containers from the yard to a ground transportation carrier  301 , the yard crane moves to a position above a ground transportation carrier  301  along a yard crane rail or the ground transportation carrier moves to a position below the yard crane along a ground transportation carrier rail  302 . The ground transportation carrier rail  302  further extends to a position below the lowest low elevated structure of the low elevated transfer system  200 . 
         [0056]    In each yard, one or two groups of ground transportation carrier rails  302  may be provided according to application requirements. 
         [0057]    Yard Crane 
         [0058]    The yard crane  400  of the present invention may be any existent gantry crane. 
         [0059]    As mentioned above, when the quayside crane  100  can hoist two 40 feet containers simultaneously, if would be better that all of the components in the system can process two 40 feet containers simultaneously so as to sufficiently utilize the production speed of the quayside crane  100 . As mentioned above, the flat carrier  500  may have an expanded base  502  for accommodating two 40 feet containers simultaneously. 
         [0060]      FIGS. 5   a  and  5   b  illustrates structure of a yard crane  400  according to an embodiment of the present invention. A beam  401  of the yard crane  400  crosses a plurality of ground transportation carrier rails  302  (two rails  302  are shown in  FIG. 4   a ). A trolley  404  that can hoist two 40 feet containers simultaneously is provided on the beam  401 , the trolley  404  moves along the beam  401  to put the containers to a certain position in the yard or on the ground transportation carrier. A traveling mechanism  403  is provided in the bottom of the yard crane  400 , the traveling mechanism  403  enable the yard crane  400  to move along a yard crane rail  402 . 
         [0061]    Low Elevated Crane 
         [0062]      FIG. 6   a - 6   c  illustrates structure of the low elevated crane according to an embodiment of the present invention. The low elevated crane  600  may be used as the low elevated crane  205  in the low elevated transfer system  200 . The low elevated crane  600  includes supports  602 , a traveling mechanism  604  is provided below the supports  602 , the traveling mechanism  604  enables the low elevates crane  600  to move along the low elevated crane rails. A platform  606  is provided above the supports  602  and a rotation plate  608  is provided on the platform  606 . A hoisting mechanism  610  and a rotation mechanism  611  is provided on the rotation plate  608 . The hoisting mechanism  610  may rotate together with the rotation plate  608 . The hosting mechanism  610  can hoist two 40 feet containers simultaneously, as shown in  FIG. 6   c . If the ground transportation carrier has rotation ability, the rotation plate  608  and the rotation mechanism  611  may be removed, and the hoisting mechanism  611  is directly mounted on the platform  606 . 
       CONCLUSION 
       [0063]    Embodiments of the present invention solve the problems in traditional container handling terminals, such as high pollution, high power consumption, low efficiency and difficult to implement informationization, automation. The new system provided in embodiments of the present invention uses a clean energy—electric as the power supply, which has higher profit and lower pollution than oil. The transportation of the system is three-dimensional, has a higher efficiency and needs less ground than the traditional plane transportation. The production process of the present invention can be informationized, automatized and intelligentized, which is a trend for all container handling terminals.