Storage system

Abstract

The present invention addresses the problem of providing a storage system capable of supplying a purge gas such as an inert gas to an article by means of a simple structure. The present invention is a storage system 10 including: a conveyance vehicle 4 that travels on a ceiling track and thereby conveys an article M; and storage equipment 12 that is located below and to the side of the ceiling track, receives the article from the conveyance vehicle, and stores the article, wherein the conveyance vehicle comprises a slide mechanism 26 for moving a placed article sideways, the storage equipment comprises a plurality of stages of storage sections arranged vertically, the storage section at the uppermost stage of the storage equipment is a fixed shelf 16 incapable of advancing or retreating sideways, the storage sections other than that of the uppermost stage are movable shelves 18 capable of advancing and retreating between a position advanced to directly below the ceiling track when viewed from above and a position shunted to the side from directly below the ceiling track, and the storage equipment additionally comprises purge equipment 32 for supplying a purge gas to an article placed on the fixed shelf at the uppermost stage.

Description

Storage System

[0001] The present invention relates to a storage system, and more particularly to a storage system for storing articles such as containers containing semiconductor wafers.

[0002] An example of a conventional storage system for transporting goods in a factory is described in Japanese Patent Application Laid-Open No. 62-297050. This storage system includes an overhead mobile vehicle for transporting goods and a rack for storing the goods. The rack is arranged below and to the side of the overhead track along which the overhead mobile vehicle travels, and includes multiple shelves arranged vertically. The shelves are designed to slide to a position directly below the overhead mobile vehicle so that goods can be transferred between the rack and the overhead mobile vehicle.

[0003] Japanese Unexamined Patent Publication No. 62-297050

[0004] In the conventional storage system described above, for example, if the item is a container containing semiconductor wafers, the container is filled with an inert gas to prevent deterioration of the semiconductor wafers. If the container is stored on a rack for a long period of time, the inert gas gradually leaks out of the container. Therefore, it is expected that the rack will be equipped with a device for purging the inert gas into the container even while the item is being stored. If the racks are arranged in multiple levels vertically, each level of the rack is equipped with movable shelves that move the item to directly below the overhead mobile vehicle. However, if the shelves are movable, the mechanism for installing purging piping becomes complex, which can cause design problems and make this difficult.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a storage system that is capable of supplying a purge gas such as an inert gas to items with a simple structure.

[0006] In order to achieve the above-mentioned object, the present invention provides a storage system comprising an overhead transport vehicle that travels on an overhead track to transport items, and storage equipment that is located below and to the side of the overhead track and receives and stores items from the overhead transport vehicle, wherein the overhead transport vehicle is equipped with a lateral movement device for moving the items it carries sideways, the storage equipment has multiple storage sections arranged in a vertical direction, the top storage section of this storage equipment is a fixed storage section that cannot move sideways, and the storage sections other than the top are movable storage sections that can move between a position advanced directly below the ceiling track and a position retracted to the side from directly below the ceiling track when viewed from above, and the storage equipment further comprises purge equipment that supplies purge gas to items placed on the top fixed storage section. In the present invention configured in this manner, the topmost storage section of the storage facility is a fixed storage section that cannot move back and forth sideways, and the storage sections other than the topmost are movable storage sections that can move back and forth between a position advanced directly below the ceiling track and a position retracted to the side from directly below the ceiling track when viewed from above.The storage facility is further equipped with purge equipment that supplies purge gas to items placed on the topmost fixed storage section.Therefore, even if the storage sections are arranged in multiple levels vertically, it is sufficient to supply purge gas to the topmost fixed storage section using the purge equipment, which simplifies the arrangement of purging piping, etc., resulting in an extremely practical storage system.

[0007] In the present invention, preferably, the movable storage units are installed on the floor and the fixed storage units are suspended from the ceiling. In the present invention configured in this manner, the movable storage units are installed on the floor and the fixed storage units are suspended from the ceiling, so that the movable storage units other than the topmost level can have a simple structure by installing the movable storage units on the floor.

[0008] In the present invention, preferably, all of the multi-tiered storage sections are suspended from the ceiling. In the present invention configured in this manner, since all of the multi-tiered storage sections are suspended from the ceiling, the space between the multi-tiered storage sections and the floor surface can be effectively utilized.

[0009] In the present invention, preferably, the fixed storage section includes a fixed shelf, and the movable storage section includes a movable shelf. In the present invention configured in this manner, the fixed storage section includes a fixed shelf, and the movable storage section includes a movable shelf, so that both storage sections can have simple structures.

[0010] In the present invention, it is preferable to further include a controller that specifies a storage section in which the items should be stored and instructs the ceiling transport vehicle to transfer the items to this storage section, and when this controller determines that it is necessary to supply purge gas to the items, it instructs the ceiling transport vehicle to transfer the items to the topmost fixed storage section, and when it determines that it is not necessary to supply purge gas to the items, it instructs the ceiling transport vehicle to transfer the items to a movable storage section other than the topmost.

[0011] The present invention is a storage system having an overhead transport vehicle that travels on an overhead track to transport items, and storage equipment located below and to the side of the overhead track that receives and stores items from the overhead transport vehicle, wherein the storage equipment comprises a plurality of first storage sections arranged in a vertical direction, and a second storage section that is fixedly arranged below these plurality of storage sections and directly below the ceiling track, and the first storage section of the storage equipment is a movable storage section that can move back and forth between a position advanced directly below the ceiling track and a position retracted to the side from directly below the ceiling track when viewed from above, and the storage equipment further comprises purge equipment that supplies purge gas to items placed on the second storage section.

[0012] According to the storage system of the present invention, it is possible to supply a purge gas such as an inert gas to an article with a simple structure.

[0013] Fig. 1 is a schematic plan view showing a conveyance system to which a storage system according to a first embodiment of the present invention is applied. Fig. 2 is a perspective view showing a storage system according to a first embodiment of the present invention. Fig. 3 is a front view showing a transport vehicle and a part of a storage unit (fixed shelf) of the storage system according to the first embodiment of the present invention. Fig. 4 is a front view showing a part of a storage unit equipped with purging equipment provided in the storage system according to the first embodiment of the present invention. Fig. 5 is a schematic view showing the system configuration of the storage system according to the first embodiment of the present invention. Fig. 6 is a flowchart showing operations executed by the storage system according to the first embodiment of the present invention. Fig. 7 is a perspective view showing a storage system according to a second embodiment of the present invention. Fig. 8 is a perspective view showing a storage system according to a third embodiment of the present invention.

[0014] Storage systems according to embodiments of the present invention will be described below with reference to the drawings. First, the basic structure of a storage system according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. In this embodiment, the present invention is applied to a storage system that stores items such as FOUPs that store semiconductor wafers and reticle pods that store reticles in a clean room of a semiconductor manufacturing factory.

[0015] First, a conveyance system to which a storage system according to a first embodiment of the present invention is applied will be described with reference to FIG. 1 . FIG. 1 is a schematic plan view showing a conveyance system to which a storage system according to the first embodiment of the present invention is applied. As shown in FIG. 1 , the conveyance system 1 to which the first embodiment of the present invention is applied includes a conveyance vehicle 4 that conveys articles to be processed in a processing device 2, a plurality of buffers 6 that are temporary storage areas for temporarily storing the articles to be transported, a plurality of intrabay tracks 7 that can transport articles to the processing device 2, and an interbay track 8 that connects these intrabay tracks 7. The conveyance system 1 further includes a controller (not shown), which controls the conveyance vehicle 4 to transport articles processed in a first processing device 2 to the buffer 6, and, after the articles have been stored in the buffer 6, transports the articles to the second processing device 2 when a second processing device 2 that will perform the next process on the articles is determined.

[0016] First, the intrabay track 7 is a traveling track made up of rails attached to the ceiling, and a plurality of processing equipment 2 are arranged along this intrabay track 7 so that items can be transported to the processing equipment 2. The transport vehicle 4 travels while suspended from the intrabay track 7, thereby transporting items M from one processing equipment 2 arranged along the intrabay track 7 to another processing equipment 2. In this way, the transport vehicle 4 is a ceiling transport vehicle that travels along a traveling track attached to the ceiling. Furthermore, the transport system 1 is equipped with a plurality of intrabay tracks 7, and the rails that make up each intrabay track 7 are suspended from the ceiling of the semiconductor manufacturing factory.

[0017] Next, the interbay track 8 is a traveling track made up of a circular rail suspended from the ceiling of the semiconductor manufacturing plant, and is connected to each intrabay track 6 via the branch track 7a. This allows the transport vehicles 2 provided in the transport system 1 to move from one intrabay track 6 to another intrabay track 6 via the interbay track 8. In other words, the transport system 1 can transport items M from a processing device 12 arranged along one intrabay track 6 to another processing device 12 arranged along another intrabay track 6.

[0018] Next, a storage system according to a first embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a perspective view showing the storage system according to the first embodiment of the present invention. As shown in Fig. 2, the storage system 10 according to the first embodiment of the present invention includes the transport vehicle 4, which is the above-mentioned ceiling transport vehicle, and storage equipment 12 for storing items M.

[0019] The storage facility 12 includes multi-tier buffers 14 arranged on both sides (the right and left sides in FIG. 2 ) of the travel direction of the transport vehicle 4. The multi-tier buffer 14 on one side (the left side) includes a fixed shelf 16 serving as a storage section at the top, and seven movable shelves 18 arranged vertically below the fixed shelf 16. The fixed shelf 16 is suspended from a ceiling 17 (see FIG. 3 ) and is unable to move laterally (widthwise). The movable shelf 18 is arranged on a floor surface 19, allowing the items M to move laterally (widthwise) up to directly below the transport vehicle 4.

[0020] The movable shelves 18 are used to receive and store items M from the transport vehicles 4, and to deliver the stored items M to the transport vehicles 4, and therefore the movable shelves 18 are capable of moving laterally. For this reason, each movable shelf 18 on each level is provided with a movement mechanism 20 for moving the movable shelf 18 laterally.

[0021] The moving mechanism 20 includes rails 20a extending laterally and provided at the bottom of each movable shelf 18, rollers 20b attached to the movable shelf 18 and running on the rails 20a, and a drive motor 20c for rotating the rollers 20b. The moving mechanism 20 moves the movable shelf 18 to directly below the transport vehicle 4, thereby enabling the delivery of the item M between the movable shelf 18 and the transport vehicle 4.

[0022] The multi-tier buffer 14 on the other side (right side) is similar to the right side, and has a fixed shelf 16 that serves as a storage section at the top, and seven movable shelves 18 arranged vertically below the fixed shelf 16. The movable shelves 18 are also provided with a movement mechanism 20 for moving the movable shelves 18 laterally, and this movement mechanism 20 also has rails 20a, rollers 20b, and a drive motor 20c.

[0023] Next, the transport vehicle 4 and the fixed shelf 16 will be described with reference to Figure 3. Figure 3 is a front view showing the transport vehicle and part of the storage section (fixed shelf) of the storage system according to the first embodiment. As shown in Figure 3, the transport vehicle 4 is suspended from rails 22 that form the intrabay track 7 and can travel by a traveling mechanism 24 to a target position. The transport vehicle 4 also includes a slide mechanism 26 and a gripping mechanism 28.

[0024] The slide mechanism 26 can extend and retract horizontally by a ball screw drive mechanism (not shown), and has a gripping mechanism 28 attached to its tip for gripping a flange M1 provided on the top of the article M. The gripping mechanism 28 also has a suspension belt 28a and a gripper 28b. Four suspension belts 28a are provided on one transport vehicle 4, and are wound around a reel (not shown) provided at the tip of the slide mechanism 26. The gripper 28b has an opening and closing function that allows it to clamp the flange M1 of the article M.

[0025] The grippers 28b are suspended from four suspension belts 28a, and are moved up and down via the suspension belts 28a by forward and reverse rotation of the reels driven by a drive device (not shown), such as a motor. The length of the suspension belts 28a is set so that the grippers 28b can grip an item M on the fixed shelf 16 and move it up and down. When the slide mechanism 26 extends and the gripping mechanism 28 moves to a position directly above the item M, the grippers 28b are lowered to above the item M. The grippers 28b are then opened and closed to clamp the flange M1. As shown in FIG. 3 , the fixed shelf 16 is an overhead buffer (OHB) suspended from the ceiling 17 by suspension rods 30.

[0026] 2 and 3, the placement and removal of an item M by the transport vehicle 4 onto and from the multi-tier buffer 14 of the storage facility 12 will be described. The removal operation of the item M is as follows. First, when removing an item M from a fixed shelf 16, the transport vehicle 4 travels along the intrabay track 7 and stops at a position opposite the multi-tier buffer 14. The transport vehicle 4 extends the slide mechanism 26 toward the topmost fixed shelf 16 of the multi-tier buffer 14. This causes the gripper 28b of the gripping mechanism 28 that is not gripping the item M to move directly above the item M. After the gripper 28b has moved directly above the target item M, the suspension belt 28a is extended, and the gripper 28b is lowered to above the specified item M on the fixed shelf 16, and the gripper 28b grips the flange M1 arranged on the item M. Next, after gripping the item M, the reel (not shown) is rotated to wind up the suspension belt 28a, raising the item M together with the gripper 28b, and then the slide mechanism 26 is retracted.

[0027] Next, when the item M on the movable shelf 18 is to be removed, the movable shelf 18 is moved laterally inward by the movement mechanism 20, and the item M on the movable shelf 18 is moved directly below the transport vehicle 4. Next, without operating the slide mechanism 26 of the transport vehicle 4, the suspension belt 28a of the gripping mechanism 28 that is not gripping the item M is extended, and the gripper 28b is lowered to above the specified item M, and the gripper 28b grips the flange M1 arranged on the item M. Next, after gripping the item M, the reel (not shown) is rotated to wind up the suspension belt 28a, and the item M together with the gripper 28b is raised to the transport vehicle 4. Thereafter, the movement mechanism 20 returns the movable shelf 18 from the position directly below the transport vehicle 4 to its original lateral position.

[0028] In this way, the transport vehicle 4 carrying the item M travels on the intrabay track 7 and interbay track 8 toward the next destination of the item M.

[0029] Next, the operation of placing the item M is as follows. First, when placing the item M on the fixed shelf 16, the placing operation is similarly performed in the reverse order of the removal operation. That is, the transport vehicle 4, which has been traveling along the intrabay track 7 with the item M gripped by the gripper 28b, stops at a predetermined position facing the fixed shelf 16 on which the item M will be placed. Next, the slide mechanism 26 is unwound to move the item M directly above the fixed shelf 16, and the reel (not shown) is rotated to extend the suspension belt 28a, lowering the gripper 28b gripping the item M to the height position of the fixed shelf 16 on which the item M will be placed. Thereafter, the gripper 28b is released, and the item M is placed on the fixed shelf 16.

[0030] Next, when placing the item M on the fixed shelf 18, the placement work is similarly performed in the reverse order of the removal. The fixed shelf 18 is moved laterally inward by the movement mechanism 20, and the movable shelf 18 is moved to directly below the transport vehicle 4. Next, without operating the slide mechanism 26 of the transport vehicle 4, the suspension belt 28a of the gripping mechanism 28 gripping the item M is extended, and the gripper 28b gripping the item is lowered to the height position of the movable shelf 18. The gripper 28b is then released, and the item M is placed on the movable shelf 18. The movement mechanism 20 then returns the movable shelf 18 from the position directly below the transport vehicle 4 to its original lateral position.

[0031] Next, the purging equipment provided on the fixed shelf of the storage system according to the first embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is a front view showing a portion of a storage section equipped with the purging equipment provided in the storage system according to the first embodiment of the present invention. As shown in Fig. 4, an item M is placed on the fixed shelf 16. As described above, this item M is a container for storing semiconductor wafers, reticles, etc. The fixed shelf 16 is provided with a purging equipment 32 for supplying a purging gas to the item M.

[0032] First, an opening M2 is formed on the side of the container (item M), and this opening M2 is closed by a lid M3. Semiconductor wafers or the like are stored inside the container (item M) through this opening M2. In addition, a purge gas inlet 34 and a purge gas outlet 36 are formed on the bottom surface of the container (item M). These purge gas inlet 34 and outlet 36 are provided with check valves (not shown).

[0033] The purge equipment 32 is equipment for supplying a purge gas into the container (item M). The purge gas is, for example, a gas inert to the items stored in the container, such as nitrogen gas. Clean dry air, which is dry air, is also used as the purge gas. The purge equipment 32 includes a purge nozzle 38 and an exhaust nozzle 40. The purge nozzle 38 and the exhaust nozzle 40 are provided on the upper surface of the fixed shelf 16. The purge nozzle 38 and the exhaust nozzle 40 are arranged so as to connect to the purge gas inlet 34 and the purge gas outlet 36 of the container (item M), respectively, when the item M is placed on the movable shelf 16. The purge nozzle 38 is connected to a purge gas supply source via piping, and the exhaust nozzle 40 is connected to a purge gas exhaust path via piping.

[0034] However, the purge gas purged into the container (item M) may leak from the sealed portion of the container lid M3, etc. Depending on the type or concentration of the purge gas, the leaked purge gas may deteriorate the surrounding environment. Therefore, in this embodiment, as shown in FIG. 4, a suction device 42 is provided to prevent the leaked purge gas from accumulating near the lid M3.

[0035] The suction device 42 includes a hood 44, which includes a wall 44a, a space 44b, and an opening 44c. The space 44b is formed inside the wall 44a, and functions as a flow path for the sucked gas. The opening 44c opens toward the lid M3 of the container (item M) and serves as an inlet for the gas flow path within the hood 44. An exhaust path 46 is connected to the outlet of the hood 44, and the sucked gas is exhausted through the opening 44c of the hood 44 via the exhaust path 46. A fan 48 is provided in the space 44b of the hood, and when the fan 48 is driven, the gas is exhausted to the outside.

[0036] Next, the system configuration of the storage system according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic diagram showing the system configuration of the storage system according to the first embodiment. As described above, the storage system 10 includes a transport vehicle 4 that travels on an intrabay track 9 and a multi-tier buffer 14 as storage equipment 12. The multi-tier buffer 14 includes a fixed shelf 16 at the top and multiple tiers of movable shelves 18 located below it. The fixed shelf 16 is provided with purge equipment 32 for supplying purge gas to containers (items M).

[0037] 5, the control devices for operating the storage system 10 include a manufacturing equipment system (MES) 50, a transport control system (MCS) 52, a purge controller 54, a transport vehicle controller 56, a fixed shelf control panel 58, and a movable shelf control panel 60. In this embodiment, when an item M is placed on the fixed shelf 16 of the multi-tier buffer 14, these control devices cause a purge gas to be purged into the container (item M).

[0038] The manufacturing management system (MES) 50 is a controller for managing production throughout the factory, the transport management system (MCS) 52 is a controller for managing the transport of items M by transport vehicles, the purge controller 54 is a controller for reporting the purging status and errors of the fixed shelves 16 to the transport management system (MCS) 52, the transport vehicle controller 56 is a controller for providing information about the transport vehicles 2 to the movable shelves 18 of the multi-tier buffer 14, the fixed shelf control panel 58 is a control panel for controlling the purging of the fixed shelves 16, and the movable shelf control panel 60 is a control panel for controlling the movement of the movable shelves 18. Note that the purge controller 54 may not be provided, and the purge status and the like may not be reported to the transport management system (MCS) 52. Furthermore, the manufacturing management system (MES) 50 determines which containers (items M) on the fixed shelves 16 to supply purge gas to.

[0039] Next, the operations performed by the storage system according to the first embodiment will be described. Fig. 6 is a flowchart showing the operations performed by the storage system according to the first embodiment of the present invention. In Fig. 6, S indicates each step. First, in S1, the transport vehicle 2 transports the item M. Next, the process proceeds to S2, where it is determined whether or not a supply of purge gas to the item M is necessary. If a supply of purge gas is necessary (YES), the process proceeds to S3.

[0040] In S3, the item M is placed on the top fixed shelf 16. Next, the process proceeds to S4, where purge gas is supplied to the item M. On the other hand, if it is determined in S2 that supply of purge gas to the item M is not necessary (NO), the process proceeds to S5. In S5, the item M is placed on a movable shelf 18 other than the top one.

[0041] Next, the effects of the storage system according to the first embodiment described above will be explained. First, in the first embodiment, the top storage section of the storage facility 12 is a fixed shelf 16 that cannot move sideways, and the storage sections other than the top storage section are movable shelves 18 that can move back and forth between a position advanced to directly below the overhead track or transport vehicle 4 and a position retracted to the side from directly below the overhead track or transport vehicle 4, as viewed from above. The storage facility 12 further includes a purge system 32 that supplies purge gas to the items M placed on the top fixed shelf 18. Therefore, even if multiple storage sections are arranged in a vertical direction, it is sufficient to supply purge gas to the top fixed shelf 16 using the purge system 32, which simplifies the arrangement of purging piping and the like, resulting in an extremely practical storage system.

[0042] Second, in the first embodiment, the movable shelves 18 are installed on the floor 19 and the fixed shelves 16 are suspended from the ceiling 17, so that the movable shelves 18 other than the topmost shelf can be simplified in structure by installing the movable shelves 18 on the floor 19. Third, in the first embodiment, the fixed shelves 16 are provided as fixed storage sections, and the movable shelves 18 are provided as movable storage sections, so that both storage sections can be simplified in structure.

[0043] Next, a storage system according to a second embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a perspective view showing the storage system according to the second embodiment of the present invention. As shown in Fig. 7, a storage system 70 according to the second embodiment of the present invention includes the transport vehicle 4, which is the above-mentioned ceiling transport vehicle, and storage equipment 12 for storing items M.

[0044] The storage facility 12 includes multi-tiered buffers 14 arranged on both sides (the right and left sides in FIG. 7 ) of the travel direction of the transport vehicle 4. The multi-tiered buffer 14 on one side (the right side) includes a fixed shelf 16 serving as a storage section on the top tier, and two tiers of movable shelves 18 below the fixed shelf 16. The top tier of the fixed shelf 16 and the two tiers of movable shelves 18 are suspended from the ceiling 17 (see FIG. 3 ) by suspension rods 72. The fixed shelf 16 itself cannot move laterally (widthwise), while the movable shelf 18 allows the items M to move laterally (widthwise) up to directly below the transport vehicle 4. As in the first embodiment described above, the fixed shelf 16 is provided with a purge facility 32 for supplying purge gas to the containers (items M).

[0045] The movable shelves 18 are the same as those in the first embodiment, and are used to receive and store items M from the transport vehicles 4, and to deliver the stored items M to the transport vehicles 4, and therefore the movable shelves 18 are capable of moving laterally. For this reason, each movable shelf 18 on each level is provided with a movement mechanism 20 for moving the movable shelves 18 laterally.

[0046] The moving mechanism 20 includes rails 20a extending laterally and provided at the bottom of each movable shelf 18, rollers 20b attached to the movable shelf 18 and running on the rails 20a, and a drive motor 20c for rotating the rollers 20b. The moving mechanism 20 moves the movable shelf 18 to directly below the transport vehicle 4, thereby enabling the delivery of the item M between the movable shelf 18 and the transport vehicle 4.

[0047] The multi-tier buffer 14 on the other side (left side) is similar to the right side, and includes a fixed shelf 16 serving as a storage section at the top, and two tiers of movable shelves 18 below the fixed shelf 16. The top fixed shelf 16 and the two tiers of movable shelves 18 are suspended from the ceiling 17 (see FIG. 3 ) by hanging rods 72. The fixed shelf 16 itself cannot move laterally (widthwise), and the movable shelf 18 allows the item M to move laterally (widthwise) up to directly below the transport vehicle 4. The movable shelf 18 is also provided with a movement mechanism 20 for moving the movable shelf 18 laterally, and this movement mechanism 20 also includes rails 20 a, rollers 20 b, and a drive motor 20 c.

[0048] Next, the effects of the storage system according to the second embodiment will be described. First, the second embodiment provides the same effects as the first and third effects provided by the storage system according to the first embodiment.

[0049] Secondly, in the second embodiment, all of the fixed shelves 16 and movable shelves 18 that make up the multi-tiered storage section are suspended from the ceiling 17, so that the space between the multi-tiered storage section and the floor surface 19 can be effectively utilized.

[0050] Next, a storage system according to a third embodiment of the present invention will be described with reference to Fig. 8. Fig. 8 is a perspective view showing the storage system according to the third embodiment of the present invention. As shown in Fig. 8, a storage system 80 according to the third embodiment of the present invention includes the transport vehicle 4, which is the above-mentioned ceiling transport vehicle, and storage equipment 12 for storing items M.

[0051] The storage facility 12 includes multi-tier buffers 14 arranged on both sides (the right and left sides in FIG. 8 ) of the travel direction of the transport vehicle 4. The multi-tier buffer 14 on one side (the right side) includes three tiers of movable shelves 18. The three tiers of movable shelves 18 are suspended from the ceiling 17 (see FIG. 3 ) by suspension rods 74. The movable shelves 18 are designed so that the items M can move laterally (in the width direction) up to directly below the transport vehicle 4. As in the first embodiment described above, the fixed shelves 16 are provided with purge equipment 32 for supplying purge gas to the containers (items M).

[0052] The movable shelves 18 are the same as those in the first embodiment, and are used to receive and store items M from the transport vehicles 4, and to deliver the stored items M to the transport vehicles 4, and therefore the movable shelves 18 are capable of moving laterally. For this reason, each movable shelf 18 on each level is provided with a movement mechanism 20 for moving the movable shelves 18 laterally.

[0053] The moving mechanism 20 includes rails 20a extending laterally and provided at the bottom of each movable shelf 18, rollers 20b attached to the movable shelf 18 and running on the rails 20a, and a drive motor 20c for rotating the rollers 20b. The moving mechanism 20 moves the movable shelf 18 to directly below the transport vehicle 4, thereby enabling the delivery of the item M between the movable shelf 18 and the transport vehicle 4.

[0054] The multi-tier buffer 14 on the other side (left side) is similar to the right side and includes three tiers of movable shelves 18. The three tiers of movable shelves 18 are suspended from the ceiling 17 (see FIG. 3 ) by hanging rods 74. The movable shelves 18 are designed so that the articles M can move laterally (widthwise) up to directly below the transport vehicle 4. The movable shelves 18 are also provided with a movement mechanism 20 for moving the movable shelves 18 laterally, and this movement mechanism 20 also includes rails 20 a, rollers 20 b, and a drive motor 20 c.

[0055] In the third embodiment, in addition to the three tiers of movable shelves 18 provided on each side as described above, a fixed shelf 16 is provided below these movable shelves 18 and directly below the transport vehicle 2. This fixed shelf 18 is suspended by the above-mentioned suspension rod 74. The fixed shelf 18 itself cannot move laterally (in the width direction).

[0056] Next, the effects of the storage system according to the third embodiment will be described. First, the third embodiment provides the same effects as the first and third effects provided by the storage system according to the first embodiment.

[0057] Secondly, in the second embodiment, all of the fixed shelves 16 and movable shelves 18 that make up the multi-tiered storage section are suspended from the ceiling 17, so that the space between the multi-tiered storage section and the floor surface 19 can be effectively utilized.

[0058] REFERENCE SIGNS LIST 1 Transport system 4 Transport vehicle 6 Buffer 7 Intra-bay track 8 Inter-bay track 10, 70, 80 Storage system 12 Storage equipment 14 Multi-stage buffer 16, 82 Fixed shelf 17 Ceiling 18 Movable shelf 19 Floor 20 Moving mechanism 20a Rail 20b Roller 20c Drive motor 22 Rail 24 Traveling mechanism 26 Slide mechanism 28 Grip mechanism 30, 72, 74 Suspension rod 32 Purge equipment 34 Inlet 36 Outlet 38 Purge nozzle 40 Exhaust nozzle 50 Manufacturing management device 52 Transport management device 54 Purge controller 56 Transport vehicle controller 58 Fixed shelf control panel 60 Movable shelf control panel M Item

Claims

1. A storage system having an overhead transport vehicle that travels on an overhead track to transport items, and storage equipment that is located below and to the side of the overhead track and receives and stores the items from the overhead transport vehicle, wherein the overhead transport vehicle is equipped with a lateral movement device for moving the items it carries sideways, the storage equipment has multiple storage sections arranged in a vertical direction, the topmost storage section of the storage equipment is a fixed storage section that cannot move sideways, and the storage sections other than the topmost are movable storage sections that can move between a position advanced directly below the ceiling track and a position retreated to the side from directly below the ceiling track when viewed from above, and the storage equipment further comprises purging equipment that supplies purging gas to items placed on the topmost fixed storage section.

2. The storage system of claim 1, wherein said movable storage unit is mounted on a floor and said fixed storage unit is suspended from a ceiling.

3. The storage system of claim 1, wherein all of said multiple storage levels are suspended from the ceiling.

4. The storage system of claim 1, wherein said fixed storage section comprises a fixed shelf and said movable storage section comprises a movable shelf.

5. A storage system as claimed in any one of claims 1 to 4, further comprising a controller which designates a storage section in which an item is to be stored and instructs the ceiling transport vehicle to transfer the item to the storage section, wherein when it is determined that it is necessary to supply purge gas to the item, the controller instructs the ceiling transport vehicle to transfer the item to the topmost fixed storage section, and when it is determined that it is not necessary to supply purge gas to the item, the controller instructs the ceiling transport vehicle to transfer the item to a movable storage section other than the topmost.

6. A storage system having an overhead transport vehicle that travels on an overhead track to transport items, and storage equipment located below and to the side of the overhead track for receiving and storing items from the overhead transport vehicle, wherein the storage equipment comprises a plurality of first storage sections arranged in a vertical direction, and a second storage section fixedly arranged below the plurality of storage sections and directly below the ceiling track, wherein the first storage section of the storage equipment is a movable storage section that can move back and forth between a position advanced directly below the ceiling track and a position retreated to the side from directly below the ceiling track in a top view, and wherein the storage equipment further comprises purging equipment that supplies purging gas to items placed on the second storage section.

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