Patent Publication Number: US-2022219746-A1

Title: Carrier device with coupling mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2021-004117, filed Jan. 14, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a carrier device comprising a coupling mechanism for coupling, for example, a caster-mounted carriage to an automatic controlled vehicle. 
     2. Description of the Related Art 
     In production sites such as factories, warehouses and the like, caster-mounted carriages are used to move objects to be carried. The caster-mounted carriages may be carts or wagons. To move the carriages to desired locations, an automatic controlled vehicle may be used. In this case, each carriage is coupled to the automatic controlled vehicle via a coupling mechanism. The coupling mechanism couples the carriage and the automatic controlled vehicle to each other as needed. The coupling mechanism can also decouple the carriage from the automatic controlled vehicle. 
     JP 2013-232078 A (Patent Literature 1) describes an automatic controlled vehicle including a coupling mechanism that uses a coupling pin. The automatic controlled vehicle is configured to be able to enter the undersides of carriages. The coupling mechanism includes a coupling pin, a drive mechanism for moving the coupling pin in the vertical direction, and a pin receiving portion. The coupling pin is provided on an upper surface of the automatic controlled vehicle. The pin receiving portion is provided on the lower surface of the carriage. The coupling pin is ascended by the drive mechanism, and then, the coupling pin is inserted to the pin receiving portion. Thus, the carriage is coupled to the automatic controlled vehicle. 
     JP 2019-162953 A (Patent Literature 2) describes an automatic controlled vehicle including a coupling portion. The coupling portion includes a coupling rod and a clamping mechanism. The coupling rod is provided on the lower surface of the carriage. The clamping mechanism is provided on the upper surface of the automatic controlled vehicle. While the automatic controlled vehicle is inserted underneath the carriage, the coupling rod is grasped with the clamping mechanism. Thus, the carriage is coupled to the automatic controlled vehicle. 
     JP 2018-24415 A (Patent Literature 3) describes an automatic controlled vehicle comprising a guide portion and a coupling mechanism. The first example of the coupling mechanism described in Patent Literature 3 includes a pair of guide portions, a coupled member and a coupling pin. The pair of guide portions are provided on the upper surface of the automatic controlled vehicle. The coupled member is provided on the lower surface of the carriage. The coupling pin is movable along the horizontal direction. The coupled member includes a pin receiving hole formed therein to insert the coupling pin thereto. While the coupled member is inserted between the guide portions, the coupling pin is inserted to the pin receiving hole. Thus, the carriage is coupled to the automatic controlled vehicle. 
     The second example of the coupling mechanism in Patent Literature 3 comprises a pair of guide portions, a pair of coupling shafts and a coupling member. The pair of guide portions are provided on the upper surface of the automatic controlled vehicle. The pair of coupling shafts are provided on the lower surface of the carriage. The coupling member is movable along the horizontal direction. While the coupling shafts are inserted between the guide portions, the coupling member is pressed against the coupling shafts. Thus, the carriage is coupled to the automatic controlled vehicle. 
     In the coupling mechanism described in Patent Literature 1, the coupling pin is inserted to the pin receiving portion. With this structure, if the relative positions of the automatic controlled vehicle and the carriage are shifted even slightly during coupling, the coupling pin cannot be inserted to the pin receiving portion. 
     The clamping mechanism described in the above-mentioned patent document 2 can be used even if the positioning accuracy of the automatic controlled vehicle relative to the carriage may be loose. However, when the automatic controlled vehicle and the carriage turned around the vertical axis, excessive load is applied to the clamping mechanism, which undesirably may easily cause damage to the clamping mechanism. 
     In the first example of Patent Literature 3, the horizontally movable metal-made coupling pin is inserted to the pin receiving hole of the metal-made coupled member. With such a structure, contact noise between the coupling pin and the pin receiving hole and vibration thereof are problematic. Especially in clean rooms where a clean environment is required, the generation of fine particles (micro-particles) by friction between metals creates a major problem. In the second example of Patent Literature 3, the coupling member is pressed against the coupling shaft. In such a structure, it is necessary to keep pressing the coupling member against the coupling rod with a large force. Therefore, a great amount of consumption energy is involved, placing a heavy load on the battery. Further, the rigidities of the coupling member and the coupling shaft need to be considerably increased. 
     The present invention provides a carrier device comprising a coupling mechanism that has a large coupling strength between the automatic controlled vehicle and the carriage and also can suppress generation of dust such as metal particles. 
     BRIEF SUMMARY OF THE INVENTION 
     According to one embodiment, a carrier device comprises a coupling mechanism that couples an automatic controlled vehicle to a carriage. The coupling mechanism comprises a first roller, a second roller, a third roller and a fourth roller. The roller are disposed on the carriage. The first roller rotates around a first axial line extending in a vertical direction. The second roller is disposed on the carriage with an interval from the first roller. The second roller rotates around a second axial line extending in the vertical direction. The third roller rotates around an axial line extending in a same direction as the first axial Line, independent of the first roller. The fourth roller rotates around an axis extending in a same direction as that of the second axis, independent of the second roller. 
     The coupling mechanism comprises a guide rail section disposed on the automatic controlled vehicle, a lock member provided in the automatic controlled vehicle and an actuator. The guide rail section includes a pair of rail members extending in a horizontal direction. Between the pair of rail members, a gap is formed, in which the first roller and the second roller can enter. The lock member moves between a first position and a second position. When the lock member is moved from the first position to the second position, the lock member is sandwiched between the third roller and the fourth roller. The actuator moves the lock member between the first position and the second position. 
     According to a carrier device comprising a coupling mechanism according to this embodiment, a large coupling strength can be obtained between the automatic controlled vehicle and the carriage, and further the generation of dust can be suppressed. 
     The coupling mechanism may include a first common shaft that supports the first roller and the third roller rotatably. The diameter of the first roller may be greater than a diameter of the third roller. The coupling mechanism may include a second common shaft that supports the second roller and the fourth roller rotatably. The diameter of the second roller may be greater than the diameter of the fourth roller. The first roller, the second roller, the third roller and the fourth roller may each comprise a roller body made of a material having rubber elasticity. 
     An example of the guide rail section may include straight portions that form longitudinal parts of the pair of rail members, respectively, a first expanding portion and a second expanding portion. In the straight portions, the rail members are parallel to each other. In the first expanding portion, the gap expands as a distance from one end of the straight portions increases. In the second expanding portion, the gap expands as a distance from the other end of the straight portion increases. 
     The lock member may include an end surface, one side surface, the other side surface and a pair of tapered surfaces. The end surface is in a front side of the lock member when moving from the first position to the second position. The one side surface and the other side surface are on a rear side when the lock member is moving. The distance between the pair of tapered surfaces decreases from the one side surface and the other side surface toward the end surface. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a perspective view of a carrier device according to a first embodiment. 
         FIG. 2  is a perspective view of the carrier device shown in  FIG. 1  while an automatic controlled vehicle thereof and a carriage are separated from each other. 
         FIG. 3  is a front view partially showing the carrier device. 
         FIG. 4  is a cross-sectional view of the carrier device taken along an axis of a first roller assembly. 
         FIG. 5  is a side view partially showing the carrier device. 
         FIG. 6  is a plan view of the automatic controlled vehicle of the carrier device. 
         FIG. 7  is a plan view showing the automatic controlled vehicle of the carrier device and a part of the carriage. 
         FIG. 8  is a plan view showing a state where the carriage is coupled by the lock member to the carrier device. 
         FIG. 9  is a plan view schematically showing a part of a carrier device according to a second embodiment. 
         FIG. 10  is a side view schematically showing a part of the carrier device shown in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A carrier device according to the first embodiment will be described with reference to  FIGS. 1 to 8 . 
       FIG. 1  is a perspective diagram showing a carrier device  10 . The carrier device  10  includes an automatic controlled vehicle  11 , a carriage  12  and a coupling mechanism  13 . The coupling mechanism  13  has the function of coupling the automatic controlled vehicle  11  and the carriage  12  to each other.  FIG. 2  shows the state where the automatic controlled vehicle  11  is separated from the carriage  12 .  FIG. 3  shows a front view of a part of the carrier device  10 . 
     The automatic controlled vehicle  11  will be explained in detail later, and the carriage  12  will be explained first. 
     The carriage  12  comprises a frame structure  20 , casters  21 ,  22 ,  23  and  24 , a first roller assembly  31  and a second roller assembly  32 . The first roller assembly  31  and the second roller assembly  32  are each provided in the frame structure  20 . The roller assemblies  31  and  32  form a part of the coupling mechanism  13 . In an upper portion of the frame structure  20 , a loading section  35  (shown in  FIGS. 1 and 2 ) is formed for loading an object to be carried thereon. 
     The frame structure  20  includes a pair of lower frames  36  and  37 , a vertical frame  38 , upper frames  40 ,  41  and  42 , a reinforcing member  43  and the like. The vertical frame  38  extends along the vertical direction. Under the upper frames  40 ,  41  and  42 , a space section  45  is formed. To the space section  45 , the automatic controlled vehicle  11  can enter from the horizontal direction. 
     The casters  21  and  22  are provided on respective ends of the lower frame  36 . The casters  23  and  24  are also provided on respective ends of the other lower frame  37 . The casters  21 ,  22 ,  23  and  24  can each rotate around a vertical axis. The casters  21 ,  22 ,  23  and  24  can change their orientations according to the direction of movement of the carriage  12 . 
     The first roller assembly  31  and the second roller assembly  32  have structures common to each other. The first roller assembly  31  is provided at a position of the upper frame  41 , which is closer to one longitudinal end  41   a  thereof. The second roller assembly  32  is provided at a position of the upper frame  41 , which is closer to the other longitudinal end  41   b  thereof. A cross section of the first roller assembly  31  is shown in  FIG. 4 . 
     As shown in  FIG. 4 , the first roller assembly  31  includes a first common shaft  50 , a first roller  51 , and a third roller  53 . The first common shaft  50  extends in the vertical direction. The first roller  51  and the third roller  53  are provided on the first common shaft  50 . The first common shaft  50  extends from the upper frame  41  downwards. The first common shaft  50  is fixed to a lower surface side of the upper frame  41  by a screw portion  50   a.    
     The first, roller  51  is attached to the first common shaft  50  by a bearing member  51   a . The first roller  51  can rotate around a first axial line X 1  (shown in  FIGS. 4 and 5 ). The first axial line X 1  extends in the vertical direction. The third roller  53  is attached to the first common shaft  50  by a bearing member  53   a . The third roller  53  can rotate around an axial line X 3  (shown in  FIG. 5 ). The axial line X 3  extends in the same direction as that of the first axial line X 1 . 
     The first roller  51  includes a roller body  51   b  (shown in  FIG. 4 ). The roller body  51   b  is made, for example, of a material having rubber elasticity such as a urethane elastomer. The third roller  53  includes a roller body  53   b . The roller body  53   b  is made, for example, of a material having rubber elasticity such as urethane elastomer. A diameter D 1  of the first roller  51  is greater than a diameter D 2  of the third roller  53 . The first roller  51  and the third roller  53  rotate around the first common shaft  50  independently of each other. 
     As shown in  FIGS. 5, 7 and 8  the second roller assembly  32  includes a second common shaft  55 , a second roller  56  and a fourth roller  57 . The second common shaft  55  extends in the vertical direction. The second roller  56  and the fourth roller  57  are provided on the second common shaft  55 . The second common shaft  55  is fixed to the lower surface side of the upper frame  41  by screws as in the case of the first common shaft  50 . The second common shaft  55  extends downwards from the upper frame  41 . 
     The second roller  56  is attached to the second common shaft  55  by a bearing member. The second roller  56  can rotate around the second axial line X 2  (shown in  FIG. 5 ). The second axial line X 2  extends in the vertical direction. The fourth roller  57  is attached to the second common shaft  55  by a bearing member. The fourth roller  57  can rotate around the axial line X 4  (shown in  FIG. 5 ). The axial line X 4  extends in the same direction as that of the second axial line X 2 . 
     The second roller  56  and the fourth roller  57  each includes a roller body. The roller body is made, for example, of a material having rubber elasticity such as urethane elastomer. The diameter of the second roller  56  is greater than that of the fourth roller  57 . The second roller  56  and the fourth roller  57  rotate around the second common shaft  55  independently of each other. 
       FIG. 8  is a plan view of the automatic controlled vehicle  11  as viewed from above. As shown in  FIG. 8 , the first roller assembly  31  and the second roller assembly  32  are arranged along an imaginary straight line M 1  extending in the horizontal direction.  FIG. 5  is a side view of a part of the automatic controlled vehicle  11 . As shown in  FIG. 5 , the first common shaft  50  and the second common shaft  55  are disposed on the upper frame  41  with a predetermined distance S 1  therebetween in the horizontal direction from each other. 
     Next, the automatic controlled vehicle  11  will be described. 
       FIG. 6  is a plan view showing the automatic controlled vehicle  11 . The automatic controlled vehicle  11  includes a vehicle main body  61  and a coupling unit  62 . The vehicle main body  61  includes a traveling mechanism  60  (shown in  FIG. 2 ). The traveling mechanism  60  is covered by a cover member  63 . The coupling unit  62  is disposed on top of the vehicle main body  61 . The vehicle main body  61  contains software and electrical components for controlling automatic operation. The vehicle main body  61  runs along a predetermined travel path. 
     The traveling mechanism  60  comprises wheels. The vehicle main body  61  moves in a first direction (indicated by arrow F 1 ) and a second direction (indicated by arrow F 2 ) by the traveling mechanism  60 . The traveling mechanism  60  also comprises a steering mechanism. The vehicle main body  61  can be swiveled around the vertical axis Z 1  by the steering mechanism. That is, the vehicle main body  61  can swivel in the first rotational direction indicated by the arrow R 1  and in the second rotational direction indicated by the arrow R 2  in  FIG. 2 . 
     The coupling unit  62  is provided on top of the vehicle main body  61 . The coupling unit  62  forms a part of the coupling mechanism  13 . The coupling unit  62  includes a base plate  70 , a guide rail section  73  including a pair of rail members  71  and  72 , a lock member  74 , an actuator  75  (shown in  FIGS. 3 and 5 ), a detecting section  77  including a plurality of sensors  76  and the like. The base plate  70  expands in substantially horizontal direction. The pair of rail members  71  and  72  are disposed on top of the base plate  70 . The lock member  74  is moved along the horizontal direction by the actuator  75 . The detecting section  77  has the function of detecting the carriage  12 . The base plate  70  is fixed to the upper surface of the vehicle main body  61  by a plurality of fixing members  79  such as bolts. 
     The pair of rail members  71  and  72  are each made of, for example, a metal plate. The rail members  71  and  72  are fixed to the base plate  70  by fixing members  80  (shown in  FIGS. 6 to 8 ). The rail members  71  and  72  includes straight portions  71   a  and  72   a , respectively. The straight portions  71   a  and  72   a  are parallel to each other and extend along the horizontal direction. The straight portions  71   a  and  72   a  form longitudinal parts of the rail members  71  and  72 , respectively. 
     Between the straight portions  71   a  and  72   a , a gap G 1  (shown in  FIG. 7 ) is formed. The gap G 1  is slightly greater than the diameter D 1  (shown in  FIG. 4 ) of the first roller  51 . The gap G 1  is slightly greater than the diameter of the second roller  56 . For example, the gap G 1  is 1 mm to several mm greater than the diameter D 1  of the first roller  51 . The gap G 1  is 1 mm to several mm greater than the diameter of the second roller  56 . With this structure, the first roller  51  and the second roller  56  can enter the gap G 1 . 
     At one end side of the guide rail section  73 , a first expanding portion  73   a  is formed. At the other end side of the guide rail section  73 , a second expanding portion  73   b  is formed.  FIG. 6  is a plan view of the automatic controlled vehicle  11  viewed from above. As viewed from above, the guide rail section  73  incudes the first expanding portion  73   a  and the second expanding portion  73   b . In the first expanding portion  73   a , as the distance from one end of the straight portion  71   a  or  72   a  increases, the distance (gap G 1 ) between the rail members  71  and  72  increases. An inlet width W 1  of the first expanding portion  73   a  is twice or more the diameter D 1  of the first roller  51 . The inlet width W 1  is also twice or more the diameter of the second roller  56 . With this structure, the first roller  51  and the second roller  56  can each easily enter between the rail members  71  and  72 . 
     In the second expanding portion  73   b , as the distance from the other end of the straight portion  71   a  or  72   a  increases, the distance (gap G 1 ) between the rail members  71  and  72  increases. An inlet width W 2  of the second expanding portion  73   b  is twice or more the diameter D 1  of the first roller  51 . The inlet width W 2  is also twice or more the diameter of the second roller  56 . With this structure, the first roller  51  and the second roller  56  can each easily enter between the rail members  71  and  72 . 
     The detecting section  77  including a plurality of sensors  76  detects at least one of the first roller assembly  31  and the second roller assembly  32  when the automatic controlled vehicle  11  enters the space section  45  of the carriage  12 . 
     As shown in  FIGS. 6 to 8 , a groove  85  is formed in the base plate  70 . The groove  85  extends in a direction perpendicular to the straight portions  71   a  and  72   a  of the rail members  71  and  72 . The lock member  74  can move horizontally along the groove  85 . The lock member  74  moves over between a first position (a standby position) shown in  FIGS. 6 and 7  and a second position (a locked position) shown in  FIG. 8 . The actuator  75  (shown in  FIGS. 3 and 5 ) is provided on the base plate  70 . The actuator  75  moves the lock member  74  to the first position and the second position. For example, the actuator  75  is a ball screw mechanism with a servo motor as the driving source. 
     As viewing the automatic controlled vehicle  11  from above, the lock member  74  includes an end portion  91  including an end surface  90 , one side surface  92 , an other side surface  93 , and a pair of tapered surfaces  94  and  95 . When the lock member  74  moves from the first position to the second position, the end surface  90  becomes the front side. The end surface  90  extends in the same direction as that of the straight portions  71   a  and  72   a  of the rail members  71  and  72 . When the lock member  74  moves from the first position toward the second position, the one side surface  92  and the other side surface  93  become the rear side. The one side surface  92  and the other side surface  93  extend in a direction parallel to the groove  85 . 
       FIG. 8  shows a distance L 1  taken between the one side surface  92  and the other side surface  93 . A distance L 2  is also taken between the third roller  53  and the fourth roller  57 . Here, note that L 1  is sufficiently greater than L 2 . A width L 3  of the end surface  90  is sufficiently smaller than the distance L 2  between the third roller  53  and the fourth roller  57 . That is, the relationship here is L 1 &gt;L 2 &gt;L 3 . In the meantime, the one tapered surface  94  is formed between the end surface  90  and one side surface  92 . The other tapered surface  95  is formed between the end surface  90  and the other side surface  93 . 
       FIG. 7  shows a distance L 4  taken between the tapered surfaces  94  and  95 . The distance L 4  decreases as the location approaches the end surface  90  from the one side surface  92  and the other side surface  93 . When the lock member  74  moves to the second position, one of the tapered surfaces  94  and  95  is brought into contact with the third roller  53  and the other tapered surface is brought into contact with the fourth roller  57 . The taper surfaces  94  and  95  with such structures are formed in the lock member  74 . Thus, even if the relative positions of the automatic controlled vehicle  11  and the carriage  12  are slightly displaced with respect to each other, the lock member  74  can enter between the third roller  53  and the fourth roller  57 . 
     Now, the operation of the carrier device  10  of this embodiment will be described. 
     First, towards the carriage  12 , which is stopped, the automatic controlled vehicle  11  moves in a direction approaching the carriage  12 . Then, the automatic controlled vehicle  11  enters the space section  45  inside the carriage  12 . When the automatic controlled vehicle  11  enters the inside of the carriage  12 , the vehicle  11  moves forward toward the gap G 1  in the guide rail section  73 . According to the moving direction of the automatic controlled vehicle  11 , the first roller  51  or the second roller  56  is guided by the first expanding portion  73   a  or the second expanding portion  73   b . Then, the first and second rollers  51  and  56  enter the gap G 1  of the guide rail section  73 . 
     The gap G 1  of the guide rail section  73  is greater than the diameter D 1  (shown in  FIG. 4 ) of the first roller  51  and the diameter of the second roller  56 . With this structure, when the first roller  51  and the second roller  56  enter the gap G 1 , the first roller  51  and the second roller  56  are rotated while touching one of the rail members  71  and  72 , respectively. Thus, the rollers  51  and  56  are rotated, it is possible to avoid generation of dust, which may be caused by the first roller  51  and the second roller  56  rubbing against the guide rail section  73 . 
       FIG. 7  illustrates the state where the automatic controlled vehicle  11  has been moved to a predetermined position (the coupling position) with respect to the carriage  12 . At this time, the lock member  74  is located at the first position (the standby position). When the automatic controlled vehicle  11  is moved to a predetermined position with respect to the carriage  12 , the roller assemblies  31  and  32  are detected by the sensors  76 , and the automatic controlled vehicle  11  is stopped. At this time, the first and second rollers  51  and  56  are located in the gap G 1  of the guide rail section  73 . 
       FIG. 8  illustrates the state where the lock member  74  has been moved to the second position (the lock position). The lock member  74  is moved from the first position to the second position by the actuator  75  (shown in  FIGS. 3 and 5 ). When the lock member  74  is moved to the second position, the relative positions of the automatic controlled vehicle  11  and the carriage  12  may be displaced with respect to each other along the length direction of the guide rail section  73 . In that case, the third roller  53  or the fourth roller  57  is brought into contact with the one tapered surface  94  or the other tapered surface  95 . 
     When the lock member  74  moves from the first position toward the second position, the third and fourth rollers  53  and  57  are brought into contact the tapered surfaces  94  and  95 , respectively. At this time, the third and fourth rollers  53  and  57  are able to rotate. Therefore, it is possible to avoid generation of particles (dust), which may occur when the lock member  74  is moved to the second position. 
     The first roller  51  and the third roller  53  are provided on the first common shaft  50 . The first roller  51  and the third roller  53  rotate independently of each other. In other words, the first roller  51  and the third roller  53  can rotate in different directions from each other. For example, when the first roller  51  enters the guide rail section  73 , the first roller  51  rotates. For example, when the lock member  74  moves toward the second position, the third roller  53  rotates. The first roller  51  and the third roller  53  can rotate independently of each other. With this structure, even if the direction of rotation of the first roller  51  and the direction of rotation of the third roller  53  are different from each other, the rotation of the first roller  51  and the rotation of the third roller  53  do not interfere with each other. Therefore, the first roller  51  and the third roller  53  can rotate without problems. 
     The second roller  56  and the fourth roller  57  are provided on the second common shaft  55 . The second roller  56  and the fourth roller  57  rotate independently of each other. In other words, the second roller  56  and the fourth roller  57  can rotate in different directions from each other. For example, when the second roller  56  enters the guide rail section  73 , the second roller  56  rotates. For example, when the lock member  74  moves toward the second position, the fourth roller  57  rotates. The second roller  56  and the fourth roller  57  can rotate independently of each other. Therefore, even if the direction of rotation of the second roller  56  and the direction of rotation of the fourth roller  57  are different from each other, the rotation of the second roller  56  and the rotation of the fourth roller  57  do not interfere with each other. Thus, the second roller  56  and the fourth roller  57  can rotate without any problem. 
       FIG. 8  shows the state in which the lock member  74  has moved to the second position. When the lock member  74  is moved to the second position, the lock member  74  is sandwiched between the third roller  53  and the fourth roller  57 . With the lock member  74  sandwiched between the third roller  53  and the fourth roller  57 , and with the first roller  51  and the second roller  56  positioned in the gap G 1  of the guide rail section  73 , the automatic controlled vehicle  11  runs. 
     For example, the automatic controlled vehicle  11  runs in the first direction F 1  (shown in  FIG. 1 ). Or, the automatic controlled vehicle  11  runs in the second direction F 2 . Here, the lock member  74  is sandwiched between the third and fourth rollers  53  and  57 , and therefore the automatic controlled vehicle  11  and the carriage  12  can be securely coupled to each other against the load applied to the coupling mechanism  13  when running. 
     Because the first and second rollers  51  and  56  are inserted to the gap G 1  of the guide rail section  73 , the relative movement of the automatic controlled vehicle  11  and the carriage  12  in the width direction is inhibited by the guide rail section  73 . When the automatic controlled vehicle  11  and the carriage  12  swivel around the vertical axis Z 1 , a load (torque) in the rotational direction is applied to the coupling mechanism  13 . Even against the load in the rotational direction, the coupling mechanism  13  can exhibit a great deal of strength. 
     While the automatic controlled vehicle  11  and the carriage  12  being coupled to each other, the automatic controlled vehicle  11  automatically runs along a predetermined route. Thus, the object to be carried out, on the carriage  12  is carried out to a predetermined location. The automatic controlled vehicle  11  and the carriage  12  may swivel around the vertical axis Z 1  in order to change direction. When the automatic controlled vehicle  11  swivels around the vertical axis Z 1 , the casters  21 ,  22 ,  23  and  24  are turned and rotated. Thus, a large force is applied to the coupling mechanism  13 . 
     Against the rotation around the vertical axis Z 1 , the first roller  51  and the second roller  56  are constrained by the guide rail section  73 . Moreover, the third and fourth rollers  53  and  57  are fixed by the lock member  74 . As a result, the coupling mechanism  13  can exhibit great strength against the load applied when the automatic controlled vehicle  11  and the carriage  12  move back and forth with relative to each other or swivel around the vertical axis Z 1 . 
     The first roller  51  and the third roller  53  of the coupling mechanism  13  of this embodiment are attached to the first common shaft  50 . Further, the second roller  56  and the fourth roller  57  are attached to the second common shaft  55 . In other words, while having four rollers  51 ,  53 ,  56  and  57 , it suffices if only two common shafts  50  and  55  are used. Such a structure exhibits the advantage of reducing the number of parts and making it easy to secure a space for mounting the common shafts  50  and  55 . 
       FIG. 9  is a plan view schematically showing a part of a coupling mechanism  13 A of a carrier device  10 A of the second embodiment.  FIG. 10  is a side view schematically showing a part of the coupling mechanism  13 A. For the carrier device  10 A, parts in common with the carrier device  10  of the first embodiment ( FIGS. 1 to 8 ) are denoted by common reference symbols with those of the carrier device  10  of the first embodiment and the explanations thereof will be omitted. 
     The coupling mechanism  13 A of the second embodiment comprises a first roller  51  and a third roller  53 , which constitutes a first roller assembly  31 , and a second roller  56  and a fourth roller  57 , which constitute a second roller assembly  32 . 
     The first roller  51  and the third roller  53  are attached to shaft members  100  and  101 , respectively, which are independent of each other. The first roller  51  rotates around the first axial line X 1 . The first axial line X 1  extends in the vertical direction. The third roller  53  rotates around the third axial line X 3 . The third axial line X 3  is parallel to the first axial line X 1  and extends in the same direction as that of the first axial line X 1 . The third roller  53  rotates independently of the first roller  51 . The diameter of the first roller  51  is greater than that of the third roller  53 . 
     The second roller  56  and the fourth roller  57  are attached to shaft members  110  and  111 , respectively, which are independent of each other. The second roller  56  rotates around the second axial line X 2 . The second axial line X 2  extends in the vertical direction. The fourth roller  57  rotates around the fourth axial line X 4 . The fourth axial line X 4  is parallel to the second axial line X 2  and extends in the same direction as that of the second axial line X 2 . The fourth roller  57  rotates independently of the second roller  56 . The diameter of the second roller  56  is greater than that of the fourth roller  57 . 
     The first roller  51  and the second roller  56  enter the gap G 1  of the guide rail section  73 . As the lock member  74  moves from the first position to the second position, the lock member  74  is sandwiched between the third roller  53  and the fourth roller  57 . In this way, the automatic controlled vehicle and the carriage can be securely coupled to each other. 
     When implementing the present invention, it is only natural to carry out by remodeling specific embodiments thereof in various ways, for the specific structures of the automatic controlled vehicle and the carriage, as well as, for example, the first and second roller assemblies, guide rail sections, lock members, actuators, etc., which constitute the coupling mechanism. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.