Patent Publication Number: US-9834236-B2

Title: Conveyance system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a conveyance system. 
     2. Description of the Related Art 
     As a conventional conveyance system, for example, the one described in Japanese Patent Application Laid-Open Publication No. 2010-67028 is known. In the conveyance system described in Japanese Patent Application Laid-Open Publication No. 2010-67028, out of a plurality of areas, some areas where conveyance vehicles can travel are set as traveling areas in accordance with the types of the conveyance vehicles, and the conveyance vehicles are controlled so as not to enter areas other than the traveling areas thus set. 
     As in the above-described conventional system, when a plurality of types of conveyance carriages travel on the same track over a plurality of areas, a conveyance carriage may enter by mistake an area where the conveyance carriage is not allowed to enter. If a conveyance carriage has entered an area where it is not allowed to enter, the conveyance carriage may interfere with a device in an area that is not designed on the assumption that the conveyance carriage enters the area. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments of the present invention provide a conveyance system that prevents conveyance carriages from mistakenly entering an area. 
     A conveyance system according to one aspect of various preferred embodiments of the present invention includes a track that extends across a plurality of areas; a first conveyance carriage that travels along the track; a second conveyance carriage that travels along the track and has a width and a height at least one of which differs from that of the first conveyance carriage; a sensor that is provided to one of the first conveyance carriage and the second conveyance carriage, arranged at a position that does not overlap the other of the first conveyance carriage and the second conveyance carriage in a traveling direction, and detects an obstacle in front; and a member to be detected that is arranged, in an entry section into a certain area where only the other of the first and second conveyance carriages is allowed to enter out of a plurality of areas, at a position where the other of the first and second conveyance carriages is allowed to enter the certain area, the position being detectable by the sensor provided to the one of the first and second conveyance carriages. 
     This conveyance system includes the first conveyance carriage and the second conveyance carriage having a width and a height at least one of which differs from that of the first conveyance carriage. One conveyance carriage out of the first conveyance carriage and the second conveyance carriage is provided with the sensor that detects an obstacle in front. In an entry section into a certain area where only the other of the first and second conveyance carriages is allowed to enter out of a plurality of areas, this sensor detects the member to be detected that is arranged at a position where the other of the first and second conveyance carriages is allowed to enter the certain area. Accordingly, in the conveyance system, the one conveyance carriage that is not allowed to enter the certain area is able to detect the member to be detected with the sensor to identify the area where entry is not allowed. Thus, the conveyance system prevents the conveyance carriages from mistakenly entering an area. 
     In one preferred embodiment of the present invention, the track may be an overhead track on a ceiling or near the ceiling. The first and second conveyance carriages may be suspended carriages that are suspended from the overhead track to travel, and the one of the first and second conveyance carriages may have a height greater than that of the other conveyance carriage. The sensor may be arranged, in the one of the first and second conveyance carriages, within a range a predetermined height below a lower end of the other of the first and second conveyance carriages. This configuration allows the sensor in the conveyance system to be arranged at a position in the one of the first and second conveyance carriages where the sensor does not overlap the other of the first and second conveyance carriages, and thus the member to be detected is arranged at a position where the member does not come in contact with the other of the first and second conveyance carriages. Furthermore, in the conveyance system including the suspended carriages (overhead conveyance vehicles), a device that is installed on a floor in the certain area that is prevented from coming in contact with the one of the first and second conveyance carriages. 
     In one preferred embodiment of the present invention, the conveyance system may include a contact sensor that is provided to the one of the first and second conveyance carriages, arranged at a position where the contact sensor comes in contact with the member to be detected, and detects contact with the member to be detected. This configuration enables the conveyance system to detect the member to be detected with the contact sensor, thus preventing the one of the first and second conveyance carriages from entering by mistake even if the member to be detected cannot be detected by the sensor. Thus, in the conveyance system, fail safe operation is properly achieved. 
     In one preferred embodiment of the present invention, the member to be detected is preferred to be arranged at a position where the member is not detected by the sensor provided to the one of the first and second conveyance carriages when the one of the first and second conveyance carriages has not entered the entry section into the certain area. By this arrangement, in the conveyance system, the sensor of the one of the first and second conveyance carriages traveling near the certain area is prevented from detecting the member to be detected. Thus, the conveyance system prevents improper operation. 
     Preferred embodiments of the present invention prevent conveyance carriages from mistakenly entering an area. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically illustrating a conveyance system according to a preferred embodiment of the present invention. 
         FIG. 2  includes diagrams of a FOUP conveyance vehicle and a reticle conveyance vehicle seen from the front. 
         FIG. 3  is a diagram illustrating a configuration of the FOUP conveyance vehicle. 
         FIG. 4  is a partially enlarged diagram of rails. 
         FIG. 5  is a front view illustrating a member to be detected. 
         FIG. 6  is a diagram illustrating a relation among the member to be detected, the FOUP conveyance vehicle, and the reticle conveyance vehicle. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will be described hereinafter in detail with reference to the attached drawings. In the description of the drawings, like reference signs are given to like or equivalent elements, and duplicated explanation is omitted. 
       FIG. 1  is a diagram illustrating a conveyance system according to a preferred embodiment of the present invention.  FIG. 2  includes diagrams of a front-opening unified pod (FOUP) conveyance vehicle and a reticle conveyance vehicle seen from the front. As depicted in  FIG. 1 , this conveyance system  1  includes a rail (track, overhead track) R, and a FOUP conveyance vehicle (first conveyance carriage)  10  that travels on the rail R, and a reticle conveyance vehicle (second conveyance carriage)  20  that travels on the rail R. In the conveyance system  1 , a plurality of types of suspended conveyance carriages (FOUP conveyance vehicle  10 , reticle conveyance vehicle  20 ) travel on the same rail R. 
     The rail R is constructed on a ceiling or near the ceiling. In the present preferred embodiment, the rail R includes a main rail R 1  and branching/merging rails R 2  to R 6  that branch from or merge into the main rail R 1 . The main rail R 1  constitutes an inter-bay route, the branching/merging rails R 2  to R 6  each constitute an intra-bay route. The branching/merging rails R 2  to R 6  are preferably provided in a plurality of (herein, five) areas A 1  to A 5 , respectively. In other words, the rail R is constructed across the areas A 1  to A 5 . In each of the areas A 1  to A 5 , various devices and a stocker (not depicted) are arranged. In the conveyance system  1 , into any of the respective areas A 1  to A 5 , entry of the FOUP conveyance vehicle  10  or the reticle conveyance vehicle  20  is restricted. 
     As depicted in  FIG. 2 , the reticle conveyance vehicle  20  is an overhead hoist transport (OHT: overhead conveyance vehicle) that conveys a reticle standard mechanical interface (SMIF) pod accommodating reticles. The reticle conveyance vehicle  20  includes a running unit  22  that runs on the rail R and a main unit  24  that includes a hoist, a belt, and a gripper. The reticle conveyance vehicle  20  is configured to convey the reticle SMIF pod and also enter an area where the reticle conveyance vehicle  20  is allowed to enter so as to be able to transport the reticle SMIF pod between various processing devices and a loading port provided to the stocker. 
     The FOUP conveyance vehicle  10  is an OHT that conveys a FOUP. The FOUP conveyance vehicle  10  includes a running unit  12  that runs on the rail R and a main unit  14  that includes a hoist, a belt, and a gripper. The FOUP conveyance vehicle  10  is configured to convey the FOUP and also enter an area where the FOUP conveyance vehicle  10  is allowed to enter so as to be able to transport the FOUP between various wafer-processing devices and a loading port provided to the stocker. 
     As depicted in  FIG. 2 , the FOUP conveyance vehicle  10  is larger than the reticle conveyance vehicle  20 . Specifically, the height of the main unit  14  of the FOUP conveyance vehicle  10  is greater than that of the main unit  24  of the reticle conveyance vehicle  20 . The difference D in height between the FOUP conveyance vehicle  10  and the reticle conveyance vehicle  20  preferably is about 100 millimeters, for example. In other words, the FOUP conveyance vehicle  10  includes a portion that does not overlap the reticle conveyance vehicle  20  in the traveling direction when traveling on the rail R. 
       FIG. 3  is a diagram illustrating a configuration of the FOUP conveyance vehicle. As depicted in  FIG. 3 , the FOUP conveyance vehicle  10  includes an optical sensor  15 , a contact sensor  16 , and a controller  17 . The optical sensor  15  detects an obstacle in front of the FOUP conveyance vehicle  10 . The optical sensor  15  is arranged on the lower end of the main unit  14 . Specifically, the optical sensor  15  is arranged on the portion that does not overlap the reticle conveyance vehicle  20 , i.e., within a range of the height difference D from the reticle conveyance vehicle  20  (within a range a predetermined height below the lower end of the main unit  24  of the reticle conveyance vehicle  20 ). The detection range of the optical sensor  15  preferably is about 100 millimeters in height and width at a distance of about five meters, for example. The optical sensor  15  outputs detection information to the controller  17  when having detected an obstacle. 
     The contact sensor  16  detects contact with an obstacle. The contact sensor  16  is arranged on the lower end of the main unit  14 . Specifically, the optical sensor  15  is arranged on the portion that does not overlap the reticle conveyance vehicle  20 , i.e., within the range of the height difference D from the reticle conveyance vehicle  20 . In the present preferred embodiment, the contact sensor  16  is arranged above the optical sensor  15 . The contact sensor  16  extends along the width direction of the main unit  14 , and also defines and functions as a bumper. The contact sensor  16  outputs detection information to the controller  17  when having detected contact with an obstacle. 
     The controller  17  is a control device that controls operation of the FOUP conveyance vehicle  10 . The controller  17  controls each component (the running unit  12  and the hoist, etc.) of the FOUP conveyance vehicle  10 . The controller  17  includes a traveling controller  18 . The traveling controller  18  controls the FOUP conveyance vehicle  10  to travel to a specified address based on an instruction from a conveyance instruction unit (not depicted). The traveling controller  18  causes the running unit  12  to perform braking control when having received detection information output from the optical sensor  15  or the contact sensor  16 . In other words, the FOUP conveyance vehicle  10  stops traveling when an obstacle has been detected by the optical sensor  15  or contact with the obstacle has been detected by the contact sensor  16 . 
     As described above, in the conveyance system  1 , in any of the respective areas A 1  to A 5 , entry of the FOUP conveyance vehicle  10  or the reticle conveyance vehicle  20  is restricted. For example, in the area A 1 , entry of the FOUP conveyance vehicle  10  is not allowed (entry of the FOUP conveyance vehicle  10  is restricted). Accordingly, in the conveyance system  1 , as depicted in  FIG. 4 , the member  30  to be detected is provided in the entry section of branching/merging rail R 2  that branches from the main rail R 1  to the area A 1 . 
       FIG. 5  is a front view illustrating the member to be detected. As depicted in  FIG. 5 , the member  30  to be detected is a plate member, for example. Both ends of the member  30  to be detected are supported by supporting members  32   a  and  32   b  at the branching/merging rail R 2 . Specifically, the member  30  to be detected is positioned at a predetermined height below the branching/merging rail R 2 , and extends in a direction orthogonal to the extending direction of the branching/merging rail R 2 . The member  30  to be detected is an obstacle that is detected by the optical sensor  15  and the contact sensor  16  of the FOUP conveyance vehicle  10 . The member  30  to be detected is arranged within the detection range of the optical sensor  15  and the contact sensor  16  of the FOUP conveyance vehicle  10  at a position where the member does not come in contact with the reticle conveyance vehicle  20 . 
     As depicted in  FIG. 6 , while the member  30  to be detected allows the reticle conveyance vehicle  20  to pass by, the member comes in contact with the FOUP conveyance vehicle  10  so as not to allow the FOUP conveyance vehicle  10  to pass by. In other words, in the conveyance system  1 , entry of the reticle conveyance vehicle  20  into the area A 1  is allowed by the member  30  to be detected, and entry of the FOUP conveyance vehicle  10  into the area A 1  is restricted by the member  30  to be detected. 
     The member  30  to be detected is arranged at a position where, even when the FOUP conveyance vehicle  10  stops in the entry section of the branching/merging rail R 2  after entering from the main rail R 1 , the FOUP conveyance vehicle  10  does not block the following FOUP conveyance vehicle  10  or the reticle conveyance vehicle  20  traveling on the main rail R 1 . Specifically, assuming that the optical sensor  15  has a detection range of about 5 meters, for example, the member  30  to be detected is arranged so that, when the FOUP conveyance vehicle  10  stops about 5 meters or short from the member  30  to be detected, the FOUP conveyance vehicle  10  stops at a position at which the FOUP conveyance vehicle  10  does not overlap another FOUP conveyance vehicle  10  or the reticle conveyance vehicle  20  traveling on the main rail R 1 . The member  30  to be detected is also arranged at a position where the member does not enter the detection range of the optical sensor  15  of the FOUP conveyance vehicle  10  traveling on the main rail R 1 . 
     The FOUP conveyance vehicle  10  that stops after detecting the member  30  to be detected is brought back to the main rail R 1  by manual operation, for example. In the conveyance system  1 , when an instruction is issued indicating that the reticle conveyance vehicle  20  enters the branching/merging rail on which the FOUP conveyance vehicle  10  is stopping, in response to the information indicating that the FOUP conveyance vehicle  10  is stopping, the reticle conveyance vehicle  20  is controlled to travel on the main rail R 1  until the FOUP conveyance vehicle  10  is brought back to the main rail R 1 . 
     As described above, in the conveyance system  1  of the present preferred embodiment, the lower end of the main unit  14  of the FOUP conveyance vehicle  10  that does not overlap the reticle conveyance vehicle  20  in the traveling direction is provided with the optical sensor  15  to detect an obstacle in front. In an entry section into a certain area where only the reticle conveyance vehicle  20  is allowed to enter out of the areas A 1  to A 5 , the optical sensor  15  detects the member  30  to be detected that is arranged at a position where the reticle conveyance vehicle  20  is allowed to enter the certain area. Accordingly, in the conveyance system  1 , the FOUP conveyance vehicle  10  that is not allowed to enter the certain area is able to detect the member  30  to be detected with the optical sensor  15  to identify the area where the FOUP conveyance vehicle  10  is not allowed to enter. Thus, the conveyance system  1  prevents the conveyance carriages from entering by mistake. 
     Accordingly, in the conveyance system  1 , a device that is installed on a floor in the certain area is prevented from coming in contact with the FOUP conveyance vehicle  10 . For example, because entry of the FOUP conveyance vehicle  10  is not assumed in the certain area where the reticle conveyance vehicle  20  is allowed to enter, the height of the device is set based on the height where the reticle conveyance vehicle  20  travels. Accordingly, if the FOUP conveyance vehicle  10  enters the certain area, the FOUP conveyance vehicle  10  may come in contact with the device. Thus, in the configuration of the present preferred embodiment in which conveyance is performed by the overhead conveyance vehicles, the configuration of the conveyance system  1  is particularly effective. 
     In the present preferred embodiment, by providing the optical sensor  15  to the FOUP conveyance vehicle  10  and also providing the member  30  to be detected that is detected by this optical sensor  15 , the conveyance system  1  prevents the conveyance carriages from entering an area by mistake. Thus, with a simple configuration, the conveyance system  1  prevents the conveyance carriages from mistakenly entering an area. The conveyance system  1  is also able to be applied to existing systems. 
     In the present preferred embodiment, the FOUP conveyance vehicle  10  includes the contact sensor  16  that is provided at a position where the contact sensor  16  comes in contact with the member  30  to be detected. This configuration enables the conveyance system  1  to detect the member  30  to be detected with the contact sensor  16 , thus preventing the FOUP conveyance vehicle  10  from entering by mistake even if the member  30  to be detected cannot be detected by the optical sensor  15 . Thus, in the conveyance system  1 , fail safe operation is properly achieved. 
     In the present preferred embodiment, the member  30  to be detected is arranged at a position where, even when the FOUP conveyance vehicle  10  stops after entering from the main rail R 1 , the FOUP conveyance vehicle  10  does not block another following FOUP conveyance vehicle  10  or the reticle conveyance vehicle  20  traveling on the main rail R 1 . Accordingly, in the conveyance system  1 , even when the FOUP conveyance vehicle  10  stops in the entry section (branching/merging rails R 2  to R 6 ) into the certain area, the following FOUP conveyance vehicle  10  or the reticle conveyance vehicle  20  is able to continue to travel. 
     In the present preferred embodiment, the member  30  to be detected is arranged at a position where the member is out of the detection range of the optical sensor  15  of the FOUP conveyance vehicle  10  traveling on the main rail R 1 . This arrangement enables the conveyance system  1  to prevent misoperation in which the optical sensor  15  of the FOUP conveyance vehicle  10  traveling on the main rail R 1  improperly detects the member  30  to be detected thus stopping the FOUP conveyance vehicle  10 . 
     The present invention is not limited to the above-described preferred embodiments. For example, in the above-described preferred embodiments, non-limiting examples have been described in which the FOUP conveyance vehicle  10  and the reticle conveyance vehicle  20  that preferably are overhead conveyance vehicles are used, but the conveyance carriages maybe carriages that travel on a floor. 
     In the above-described preferred embodiments, assuming as one non-limiting example a configuration in which the height of the FOUP conveyance vehicle  10  is greater than the height of the reticle conveyance vehicle  20 , a configuration in which the sensor is provided to the lower end of the main unit  14  of the FOUP conveyance vehicle  10  has been described as one non-limiting example. However, when the width of one of the conveyance carriages is greater than that of the other conveyance carriage, the sensor may be provided to one end in the width direction. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.