Abstract:
A moving unit, an elevation device, or the like is prevented from laterally projecting from an overhead travelling vehicle and interfering with a stationary device or an overhead travelling vehicle in the neighborhood thereof. Projection from an overhead travelling vehicle is prevented, the vehicle including a travelling unit, an elevation device lifting and lowering articles, and a lateral movement mechanism including a base member supported by the travelling unit and a moving unit laterally moving while supporting the elevation device. The moving unit is moved between a state in which it laterally protrudes from the travelling unit and a state in which it is retracted to a position under the travelling unit. The moving unit or the elevation device is engaged with the base member or the travelling unit in the state in which the moving unit is retracted to the position under the travelling unit.

Description:
CROSS-REFERENCE 
       [0001]    The present application is a National phase of PCT/P2010/058808, filed on May 25, 2010, and published as WO2011/148459. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to preventing a. transfer device from unintentionally projecting from an overhead travelling vehicle. 
       BACKGROUND OF THE INVENTION 
       [0003]    JP2008-127200A proposes a lateral movement mechanism on an overhead travelling vehicle to laterally move an elevation device that lifts and lowers articles. The lateral movement mechanism is configured of, for example, a belt-driven slide fork, and if the belt is cut, a moving unit of the slide fork may unintentionally project and interfere with an overhead travelling vehicle opposite thereto or for example, a strut of a buffer in the neighborhood thereof. 
         [0004]    There is a need in the art to prevent a moving unit from unintentionally projecting even when trouble has occurred with a lateral movement mechanism. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is directed to an overhead travelling vehicle including a travelling unit, an elevation device lifting and lowering articles, and a lateral movement mechanism, 
         [0006]    the lateral movement mechanism including a base member supported by the travelling unit and a moving unit supporting the elevation device, the base member moving the moving unit between a state in which the moving unit laterally protrudes from the travelling unit and a state in which the moving unit is retracted to a position under the travelling unit, the overhead travelling vehicle including: 
         [0007]    an engagement device engaging the moving unit or the elevation device with the base member or the travelling unit in the state in which the moving unit is retracted to the position under the travelling unit. 
         [0008]    The present invention is also directed to a method for preventing projection from an overhead travelling vehicle including a travelling unit, an elevation device lifting and lowering articles, and a lateral movement mechanism including a base member supported by the travelling unit and a moving unit laterally moving while supporting the elevation device, the method including: 
         [0009]    a step for moving the moving unit between a state in which the moving unit laterally protrudes from the travelling unit and a state in which the moving unit is retracted to a position under the travelling unit; and 
         [0010]    a step for engaging the moving unit or the elevation device with the base member or the travelling unit in the state in which the moving unit is retracted to the position under the travelling unit. 
         [0011]    The moving unit or the elevation device is engaged with the base member or the travelling unit, and therefore the moving unit or the elevation device will not unintentionally project. Although an example in which the moving unit is engaged with the base member will be described in an embodiment, the moving unit may be engaged with the travelling unit, or the elevation device may be engaged with the base member. 
         [0012]    Preferably, the moving unit or the elevation device has a member provided with a hole for engagement, and the engagement device includes at least one pin that is advanced and retracted between a state in which the pin is engaged in the hole and a state in which the pin is disengaged from the hole, and a mechanism for advancing and retracting the at least one pin. With this configuration, the engagement and disengagement can be performed in a simple manner by advancing and retracting the pin. The member provided with a hole for engagement may be, for example, the moving unit itself or may he a separate member provided on the moving unit. 
         [0013]    Preferably, the moving unit includes a top unit supporting the elevation device and a middle unit disposed between the base unit and the top unit, each of the top unit and the middle unit has the member provided with a hole for engagement, and the engagement device engages and disengages the at least one pin in and from the respective holes for engagement of the top unit and the middle unit. With this configuration, the top unit and the middle unit can be each individually engaged and anchored. In particular, in cases where separate members are used as a member, such as a belt, that drives the middle unit and a member, such as a belt, that drives the top unit, a situation in which even though only the middle unit or the top unit is engaged, the other member projects is conceivable. In contrast, when both of the top unit and the middle unit are engaged, neither of the members unintentionally projects. 
         [0014]    More preferably, the engagement device advances and retracts the at least one pin such that the pin is engaged in the respective holes for engagement of the top unit and the middle unit with a single stroke and disengaged therefrom with a single stroke. When engagement is established with a single stroke and the engagement is released with a single stroke, control is unnecessary between the engagement and the disengagement, so that the reliability of control is increased. Moreover, when engagement and disengagement are performed with a single stroke, the engagement and the disengagement can be performed quickly. 
         [0015]    Particularly preferably, the at least one pin is two pins located at different positions in a plan view, and the holes for engagement of the top unit and the middle unit are located at different positions in a plan view. With this configuration, as compared with cases where two holes are overlapped with each other in a plan view and a single pin is moved up and down with a long stroke, the pins can be reliably moved up and down with a short stroke. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a front view showing an overhead travelling vehicle according to an embodiment and travelling rails and buffers in the neighborhood thereof. 
           [0017]      FIG. 2  is a plan view of relevant portions of a lateral movement mechanism of the overhead travelling vehicle according to the embodiment. 
           [0018]      FIG. 3  is a side view showing the relevant portions of the lateral movement mechanism and an engagement device of the overhead travelling vehicle according to the embodiment. 
           [0019]      FIG. 4  is a horizontal cross-sectional view taken along line III-III in  FIG. 3 . 
           [0020]      FIG. 5  is a side view showing an engagement device and relevant portions of a lateral movement mechanism according to a variation. 
           [0021]      FIG. 6  is a plan view showing the engagement device and relevant portions of the lateral movement mechanism according to the variation. 
           [0022]      FIG. 7  is a side view showing an engagement device and relevant portions of a lateral movement mechanism according to a second variation. 
           [0023]      FIG. 8  is a plan view showing a pin of the engagement device and relevant portions of the lateral movement mechanism according to the second variation. 
           [0024]      FIG. 9  is a side view showing an engagement device and relevant portions of a lateral movement mechanism according to a third variation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]      FIGS. 1 to 9  show an embodiment and variations thereof. In the figures, reference numeral  2  denotes an overhead space such as an overhead space in a clean room, and below  FIG. 1  are a semiconductor processing device and the like (not shown). Reference numeral  4  denotes a ceiling, such as a ceiling of a clean room, which supports rails  10  for an overhead travelling vehicle  20  via struts  6  and support members  8 . The rails  10  each include, for example, a travelling rail  11  and an electricity feeding rail  12 , and struts  15  and  16  supports a buffer  14  for articles such as a FOUP  35  to be temporarily placed thereon. The buffer  14  may be replaced with an appropriate automated storage and retrieval system, stocker, or the like, and a buffer  14   a  between the right and left travelling rails  10 ,  10  in  FIG. 1  may not be provided. Furthermore, although the lateral pair of travelling rails  10 ,  10  is provided in  FIG. 1 , it is also possible that only one of these is provided. 
         [0026]    The overhead travelling vehicle  20  includes a travel driving unit and an electricity receiving unit, which are not shown; the travel driving unit is disposed in the travelling rail  11 , and the electricity receiving unit is disposed in the electricity feeding rail  12  and receives electricity from a non-contact electricity feeder line or the like provided in the rail  12 . The travel driving unit and the electricity receiving unit are collectively referred to as a travelling unit. A shaft extending from the travelling unit supports a slide fork  21 , and the travelling unit supports a base unit  22  thereof. Below the base unit  22  are a middle unit  24  and a top unit  26 , which are advanced and retracted on both sides m a lateral direction in  FIG. 1  to laterally move a rotary device  28 , the FOUP  35 , and components disposed therebetween. The slide fork  21  corresponds to a lateral movement mechanism, and the middle unit  24  and the top unit  26  correspond to a moving unit. The slide fork  21  may be of a type that protrudes to only one of the right and left sides, instead of a type that protrudes to both the right and left sides. 
         [0027]    The rotary device  28 , which rotates an elevation device  30  around a vertical axis, may not be provided, and, in the claims, the rotary device  28  is regarded as a part of an elevation device. The elevation device  30  lifts and lowers an elevation platform  32  through a suspending material such as a belt, a rope, or a wire, and the elevation platform  32  grips or releases articles such as the FOUP  35  through, for example, a pair of claws  33 . An engagement device  34  is attached to the base unit  22  or the travelling unit and engaged with the middle unit  24  and the top unit  26  so as to prevent these units from unintentionally projecting in the lateral direction. The configuration of the engagement device  34  will be described later with reference to  FIGS. 3 to 9 . 
         [0028]      FIG. 2  shows an example of the configuration of the slide fork  21 ; however, there is no limitation to this. Reference numerals  36  to  38  denote belts, and of these belts, the belt  36  is a driving belt and the belts  37  and  3 S are follower belts. Reference numeral  40  denotes a driving pulley, which drives the belt  36  through a driving motor  41 , and idler pulleys  42  and  43  are provided for the belts  37  and  38 . Reference numerals  44  to  49  denote fixed ends of the belts  36  to  38 . The driving pulley  40  and the fixed ends  44 ,  46 , and  48  are provided on the base unit  22 , and the idler pulleys  42  and  43  and the fixed end  45  are provided on the middle unit  24 . The fixed ends  47  and  49  are provided on the top unit  26 . 
         [0029]    Guide members  50  and rails  51  are provided between the base unit  22  and the middle unit  24 , and stoppers  52  and  53  are provided, for example, on opposite ends of each rail  51 . Here, the rails  51  are provided on the middle unit  24  and the guide members  50  are provided on the base unit  22 ; however, the rails and the guide members ma be arranged conversely. Similarly, guide members, rails, and stoppers are also provided between the middle unit  24  and the top unit  26 . As described above, when the belt  36  is driven by the driving pulley  40 , the belts  37  and  38  follow, so that the middle unit  24  laterally moves to the right and left sides of the base unit  22 , and the top unit  26  moves to both the right and left sides with a stroke that is, for example, twice the stroke of the middle unit  24 . 
         [0030]      FIGS. 3 and 4  show the configuration of the engagement device  34  according to the embodiment. The middle unit  24  is provided with an engagement member  56  having an L-shape as viewed from the side, and the top unit  26  is also provided with an engagement member  57  having an L-shape as viewed from the side as well. The L-shaped engagement members  56  and  57  have a horizontal end, and the two end portions are arranged, for example, at mutually different height positions so as to be overlapped with each other in a plan view. A hole  58  is provided in the end of the engagement member  56 , and a hole  59  is provided in the end of the engagement member  57 . The engagement device  34  vertically moves as pair of pins  54  and  55 , thereby advancing and retracting these pins into and from the holes  58  and  59 , respectively, and the pins  54  and  55  are attached to a plate  70 . Moreover, for example, a pair of shafts  68  is attached to the plate  70  to connect this plate to a magnetic plate  65  via a guide  66 . A shall  63  of a solenoid  62  is connected to the magnetic plate  65 , and the shaft  63  is pressed downward by a spring  64 . 
         [0031]    As a result, when an electric current is passed through the solenoid  62 , a coil is excited, so that the magnetic plate  65  is attracted as shown in  FIG. 3 , and the pins  54  and  55  are moved up out of engagement with the holes  58  and  59 . When the electric current to the solenoid  62  is turned off, the shaft  63  moves down due to the spring  64 , and the pins  54  and  55  are brought into engagement with the holes  58  and  59 . Thus, unless an electric current is passed through the solenoid  62 , lateral movement of the base unit  22  and the top unit  26  is inhibited. In addition, control of the solenoid  62  is simple, and both the engagement operation and the disengagement operation thereof are performed with a single stroke. Since the separate pins  54  and  55  are provided for the holes  58  and  59 , respectively, the upward and downward stroke of the pins  54  and  55  can be reduced. Accordingly, engagement and disengagement cart be performed reliably in as short period of time by simple control. 
         [0032]    The above embodiment has advantages such as the following. Even in the case where the belts  36  to  38  are cut for some reason, the middle unit  24  or the top unit  26  does not laterally project unless an electric current is passed through the solenoid  62 . Thus, the top unit  26 , the elevation device  30 , the components disposed therebetween, and the like do not interfere with another overhead travelling vehicle travelling along the rail  10  opposite thereto. Also, there is no interference with the buffer  14  and the like provided to the right and left thereof. The engagement of the middle unit  24  and the top unit  26  is established using, for example, the pair of pins  54  and  55 , and since these pins can be driven by the same solenoid  62 , control is simple, and, moreover, since the separate pins  54  and  55  are provided for the respective holes  58  and  59 , the stroke can be reduced. Although the middle unit  24  and the top unit  26  are engaged in the above embodiment, the rotary device  28  or the elevation device  30  may be engaged with the base unit  22  instead. Furthermore, if, in addition to the base unit  22 , there is any member connected to the travelling unit side, the engagement device  34  may be attached to that member. 
         [0033]      FIGS. 5 and 6  show an engagement device according to a variation, and the other aspects of this variation are similar to the embodiment shown in  FIGS. 1 to 4 . in  FIGS. 5 and 6 , end portions of engagement members  76  and  77  are made to be at the same height to make holes  78  and  79  be at the same height. As a result, ends of pins  74  and  75  are located at the same height position. In this case, the stroke necessary for the pins is the stroke for advancement into and retraction from the holes  78  and  79 , and remains unchanged from that of the embodiment shown in  FIGS. 1 to 4 . 
         [0034]      FIGS. 7 and 8  show a second variation. Reference numeral  81  and  82  denote new engagement members; the engagement member  81  is attached to, for example, a middle unit, and the engagement member  82  is attached to for example, a top unit. Holes  83  and  84  that are overlapped with each other a plan view are provided M an end of the respective engagement members  81  and  82 , and a single pin  85  is advanced into and retracted from these boles. With this configuration, when compared with the above embodiment, the stroke is increased by a distance S in  FIG. 7 , and a stronger solenoid and a stronger spring are necessary. 
         [0035]    Although the slide fork  21  is used as the lateral movement mechanism in the above-described embodiment and variations, a SCARA (Selective Compliance Assembly Robot Arm) arm or the like may also be used.  FIG. 9  shows an example in which a SCARA arm is used as the lateral movement mechanism, and aspects other than those particularly pointed out are similar to the above embodiment. Reference numeral  90  denotes a SCARA arm, which is configured of an upper arm  91  and a lower arm  92 , and, for example, engagement members  56  and  57  are provided in the neighborhood of a shaft that connects the upper arm  91  and the lower arm  92  to each other, and a pair of pins  54  and  55  is advanced and retracted by an engagement device  34  as in the embodiment shown in  FIGS. 1 to 4 . The engagement device  34 , the engagement members  56  and  57 , and the like may be provided on the side of a shall  96  that connects a main body portion  94  and the upper arm  91  to each other. 
       DESCRIPTION OF REFERENCE NUMERALS 
       [0036]      2  overhead space 
         [0037]      4  ceiling 
         [0038]      6  strut 
         [0039]      8  support member 
         [0040]      10  rail 
         [0041]      11  travelling rail 
         [0042]      12  electricity feeding rail 
         [0043]      14  buffer 
         [0044]      15 ,  16  strut 
         [0045]      20  overhead travelling vehicle 
         [0046]      21  slide fork 
         [0047]      22  base unit 
         [0048]      24  middle unit 
         [0049]      26  top unit 
         [0050]      28  rotary device 
         [0051]      30  elevation device 
         [0052]      32  elevation platform 
         [0053]      33  claw 
         [0054]      34  engagement device 
         [0055]      35  FOUP 
         [0056]      36  to  38  belt 
         [0057]      40  driving pulley 
         [0058]      41  driving motor 
         [0059]      42 ,  43  idler pulley 
         [0060]      44  to  49  fixed end 
         [0061]      50 ,  60  guide member 
         [0062]      51 ,  61  rail 
         [0063]      52 ,  53  stopper 
         [0064]      54 ,  55  pin 
         [0065]      56 ,  57  engagement member 
         [0066]      58 ,  59  hole 
         [0067]      62  solenoid 
         [0068]      63 ,  68  shaft 
         [0069]      64  spring 
         [0070]      65  magnetic plate 
         [0071]      66  guide 
         [0072]      70  plate 
         [0073]      72 ,  73  bolt 
         [0074]      74 ,  75  pin 
         [0075]      76 ,  77  engagement member 
         [0076]      78 ,  79  hole 
         [0077]      81 ,  82  engagement member 
         [0078]      83 ,  84  hole 
         [0079]      85  pin 
         [0080]      90  SCARA arm 
         [0081]      91  upper arm 
         [0082]      92  lower arm 
         [0083]      94  main body portion 
         [0084]      95 ,  96  shaft