Transferring containers in storage system

1. A storage system comprising:

first and second storage sections, each configured for storing containers arranged in multiple rows at various horizontal levels with respect to ground, and

a first group of transportation devices configured for moving in a horizontal direction along corresponding pairs of rails arranged at multiple horizontal levels in a passage between the first storage section and the second storage section so as to have access to the containers arranged in both the first and second storage sections, wherein

each transportation device movable along a corresponding pair of rails is configured to include a container access mechanism movable up with respect to the corresponding pair of rails so as to handle one or more containers stored in a row above the corresponding pair of rails, and movable down with respect to the corresponding pair of rails so as to handle one or more containers stored in a row below the corresponding pair of rails,

the first group of transportation devices includes a first transportation device movable along a first pair of rails, and a second transportation device movable along a second pair of rails arranged above the first pair of rails,

the first transportation device is configured to access containers arranged in the first and second storage sections at a first set of rows, and the second transportation device is configured to access containers arranged in the first and second storage sections at a second set of rows provided above the rows of the first set,

the first set and the second set include a pre-determined number of rows common to the both first and second sets, the number of common rows is less than the number of rows in the first set and the number of rows in the second set.

2. The system of claim 1 further comprising a third storage section configured for storing containers arranged in multiple rows at various horizontal levels with respect to ground, and a second group of transportation devices configured for moving in a horizontal direction along corresponding pairs of rails arranged at multiple horizontal levels in a passage between the second storage section and the third storage section so as to have access to the containers arranged in both the second and the third storage sections.

3. The system of claim 2 , wherein the second group of transportation devices includes a third transportation device movable along a third pair of rails arranged at a horizontal level corresponding to the first pair of rails, and a fourth transportation device movable along a fourth pair of rails arranged above the third pair of rails at a horizontal level corresponding to the second pair of rails.

4. The system of claim 3 , wherein the third transportation device is configured to access containers arranged in the second and third storage sections at the first set of rows, and the fourth transportation device is configured to access containers arranged in the second and third storage sections at the second set of rows.

5. The system of claim 4 , wherein the first transportation device is configured for loading a selected container from a first slot in a first row of the first storage section and unloading the selected container to a second slot in a second row of the second storage section, where the second row is a row common to the both first and second sets of rows.

6. The system of claim 5 , wherein the second row differs from the first row.

7. The system of claim 6 , wherein the fourth transportation device is configured for loading the selected container from the second slot and unloading the selected container to a third slot in a third row of the third storage section, where the third row differs from the second row.

8. The system of claim 1 , wherein each transportation device includes a frame movable along the corresponding pair of rails and a movable platform configured to move up with respect to the frame to take a container arranged in a row above the corresponding pair of rails, and configured to move down with respect to the frame to take a container arranged in a row below the corresponding pair of rails.

9. A method of transferring containers in a storage system including multiple storage sections, each configured for storing containers arranged in multiple rows at various horizontal levels with respect to ground, and at least one group of transportation devices configured for moving in a horizontal direction along corresponding pairs of rails arranged at various horizontal levels in a passage between adjacent storage sections so as to have access to the containers arranged in the adjacent storage sections, each transportation device in the group being configured for accessing containers arranged at a set of rows, adjacent sets of rows include a predetermined number of common rows less than the number of rows in each of the adjacent sets, the method comprising:

configuring a first transportation device in a first group of transportation devices for accessing containers arranged in first and second storage section at a first set of rows, and

transferring a selected container by the first transportation device from a first row in a first set of rows in the first storage section to a second row in the second storage section common to the first set of rows and the second set of rows, where the second row differs from the first row.

10. The method of claim 9 , further comprising the steps of:

configuring a second transportation device in a second group for accessing containers arranged in the second storage section and a third storage section at a second set of rows adjacent the first set of rows, and

transferring the selected container by the second transportation device from the second row in the second storage section to a third row in the third storage section.