Abstract:
There is provided a seedbed holding unit capable of reliably and firmly holding a seedbed with a simple structure, causing no damage to a plant. A seedbed holding unit  160  that holds a seedbed B used in plant cultivation includes a first holding member  170  and a second holding member  180  that are rotatable relative to each other about a predetermined rotation axis A, the first holding member  170  is provided with a first claw part  173  in a fixed state, the second holding member  180  is provided with a second claw part  183  in a fixed state, and the seedbed B is held between the first claw part  173  and the second claw part  183  by rotating the first holding member  170  and the second holding member  180  relative to each other.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a seedbed holding unit that holds a seedbed used in plant cultivation, and more particularly to a seedbed holding unit that is used in plant transplantation. 
       BACKGROUND ART 
       [0002]    In the prior art, there is known an automatic planting device for a hydroponic seedling, which includes a seedbed transfer conveyor that transfers a seedbed by performing intermittent rotation and lateral reciprocation, a planting panel transfer conveyor that is provided below the seedbed transfer conveyor and transfers a planting panel by performing the intermittent rotation, several transfer opening/closing holders that are positioned above the front end part of the seedbed transfer conveyor, hold and separate several seedbed pieces positioned collectively in the front end row of the seedbed on the seedbed transfer conveyor, and transfer the seedbed pieces forward, several insertion opening/closing holders that are positioned in front of the several transfer opening/closing holders, hold and lower the seedbed pieces transferred by the transfer opening/closing holders, and plant the seedbed pieces by inserting same into holes of the planting panel on the planting panel transfer conveyor, and an operation mechanism that is coupled to the seedbed transfer conveyor and causes the seedbed transfer conveyor to intermittently reciprocate in a lateral direction by the width of the seedbed piece of the seedbed (see, e.g., Patent Literature 1). 
         [0003]    In the automatic planting device described in Patent Literature 1, the opening/closing holder (the transfer opening/closing holder and the insertion opening/closing holder) configured to hold the seedbed using a pair of holding pieces capable of linearly moving closer to and away from each other is used as a seedbed holding unit that holds the seedbed. 
       CITATION LIST 
     Patent Literature 
       [0004]    Patent Literature 1: Japanese Patent Application Laid-open No. 2000-4699 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    The opening/closing holder described in Patent Literature 1 requires a movement space S for the pair of holding pieces  570  and  580  to move closer to and away from each other in a lateral direction. Accordingly, as shown in Reference Example in  FIG. 9 , in the case where the pair of the holding pieces  570  and  580  are caused to pass through a hole  521  of a predetermined size and hold a seedbed B positioned beyond the hole  521 , it is necessary for the holding pieces  570  and  580  to have a sufficient length. In addition, in the case where limitations are posed on the entire width of the holding pieces  570  and  580  including the movement space S, it is necessary to design each holding piece such that the width thereof is reduced with consideration to the movement space S, so it becomes difficult to secure the rigidity of the holding pieces  570  and  580 . As a result, the holding pieces  570  and  580  are more susceptible to deformation and thus incapable of holding the seedbed B firmly, resulting in the problem of slippage of the seedbed B and a failure to hold same. 
         [0006]    In addition, as in the opening/closing holder described in Patent Literature 1, in the case where the seedbed B is held by the pair of the holding pieces  570  and  580  capable of moving closer to and away from each other, it is not possible to separately hold each of a plurality of portions (C 1 , C 2 , C 3 , and C 4  shown in  FIG. 9 ) of the seedbed B that are spaced part in a direction X in which the holding pieces  570  and  580  move closer to and away from each other, and hence certain limitations are posed on the design of the portion of the seedbed B to be held, e.g. it is not possible to hold the four corners C 1  to C 4  on the lower surface of the seedbed B separately, as shown in  FIG. 9 . 
         [0007]    The present invention has been devised to solve these problems, and an object thereof is to provide a seedbed holding unit capable of reliably and firmly holding the seedbed with a simple structure, causing no damage to a plant. 
       Solution to Problem 
       [0008]    The present invention is a seedbed holding unit that holds a seedbed used in plant cultivation, the seedbed holding unit including a first holding member and a second holding member that are rotatable relative to each other about a predetermined rotation axis, wherein the first holding member is provided with a first claw part in a fixed state, the second holding member is provided with a second claw part in the fixed state, and the seedbed is held between the first claw part and the second claw part by rotating the first holding member and the second holding member relative to each other, whereby the above problem is solved. 
       Advantageous Effects of Invention 
       [0009]    According to a first aspect of the present invention, by configuring the seedbed holding unit such that the seedbed is held between the first claw part of the first holding member and the second claw part of the second holding member by rotating the first holding member and the second holding member relative to each other, unlike the conventional seedbed holding unit configured such that the seedbed is held between a pair of the holding pieces that are capable of moving closer to and away from each other, it is not necessary to secure the movement space for causing the first holding member and the second holding member to move closer to and away from each other in the lateral direction, and hence, even in the case where the holding member is caused to pass through a hole of a predetermined size, it is possible to secure the sufficient width of each holding member. With this, it is possible to secure the rigidity of each holding member, and reliably and firmly hold the seedbed without causing deformation in each holding member. 
         [0010]    In addition, by adopting the configuration in which the seedbed is held between the first claw part and the second claw part by moving the first claw part and the second claw part in a circumferential direction, unlike the conventional seedbed holding unit, limitations, such as the impossibility to separately hold each of a plurality of portions of the seedbed that are spaced apart in a direction in which the holding pieces move closer to and away from each other, are not posed, and hence flexibility in design related to the portion of the seedbed to be held is improved, and it is possible to reliably and stably hold the seedbed in accordance with the form of the seedbed. 
         [0011]    According to a second aspect of the present invention, by providing the first holding member with a plurality of the first claw parts in a fixed state and providing the second holding member with a plurality of the second claw parts in a fixed state, it is possible to reliably synchronize timings of holding by the plurality of the claw parts, and hence it is possible to hold a plurality of portions of the seedbed at the same time using the plurality of the claw parts and, in particular, even in the case where the outer edge of the seedbed is held instead of holding a portion near the center of the seedbed in order to avoid damage to a plant, it is possible to hold a plurality of portions in the outer edge of the seedbed so that it is possible to grasp the seedbed in a well-balanced manner. 
         [0012]    According to a third aspect of the present invention, the first claw part and the second claw part are provided on outer edge sides of a first claw supporting part and a second claw supporting part, whereby it is possible to hold a portion near the outer edge of the seedbed using the claw parts instead of the portion near the center of the seedbed in which seeds and roots of the plant are retained, and hence it is possible to firmly hold the seedbed without damaging the plant retained in the seedbed. 
         [0013]    According to a fourth aspect of the present invention, the second holding member has a pipe part, and the first holding member has a shaft part that extends along the rotation axis and is inserted into the pipe part, whereby it is possible to bear the shaft part of the first holding member using the pipe part of the second holding member, and hence a necessity to additionally provide a bearing member is eliminated, the occurrence of a trouble is prevented by simplifying the structure, and it is possible to achieve a reduction in the size of each of the first holding member and the second holding member. In addition, by disposing the shaft part of the first holding member inside the pipe part of the second holding member, it is possible to prevent an increase in size in the lateral direction even in the case where the rigidity of each of the pipe part and the shaft part is secured. 
         [0014]    According to a fifth aspect of the present invention, by fixing the second holding member having the pipe part to a base part and rotationally driving the first holding member having the shaft part disposed in the pipe part, it is possible to prevent the rotationally driven shaft part from being exposed to the outside to secure the safety of a user, and the design of a peripheral environment is facilitated. 
         [0015]    According to a sixth aspect of the present invention, by driving the base part using an advance/retreat driving part such that the base part is able to advance or retreat along the rotation axis direction, it is possible to insert or pull out the seedbed into or from a seedbed retaining part formed in a container or the like in a state in which the seedbed is held by the claw parts, and hence it is possible to stably and smoothly perform a transplantation operation of the seedbed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a perspective view showing a plant-transplanting device into which a seedbed holding unit as a first embodiment of the present invention is incorporated. 
           [0017]      FIG. 2  is a front view showing the plant-transplanting device. 
           [0018]      FIG. 3  is an explanatory view showing a seedbed. 
           [0019]      FIG. 4  is an explanatory view showing the seedbed holding unit in a state in which claw parts are spaced apart. 
           [0020]      FIG. 5  is an explanatory view showing the seedbed holding unit in a state in which the claw parts are in contact with each other. 
           [0021]      FIG. 6  is a cross-sectional view showing the seedbed holding unit. 
           [0022]      FIG. 7  is an explanatory view showing a seedbed transplanting flow. 
           [0023]      FIG. 8  is an explanatory view showing a seedbed holding unit as a second embodiment of the present invention. 
           [0024]      FIG. 9  is an explanatory view showing a seedbed holding unit as Reference Example. 
       
    
    
     REFERENCE SIGNS LIST 
       [0000]    
       
           100  Plant-transplanting device 
           110  Plant holder 
           120  Cultivation pallet 
           130  Holder retaining/moving mechanism 
           140  Pallet retaining mechanism 
           150  Transferring mechanism 
           151  Supporting part 
           152  Lateral linear actuator 
           153  Longitudinal linear actuator 
           160 ,  260  Seedbed holding unit 
           170 ,  270  First holding member 
           171  Shaft part 
           172 ,  272  First claw supporting part 
           173 ,  273  First claw part 
           174  Driven part 
           180 ,  280  Second holding member 
           181 ,  281  Pipe part 
           182 ,  282  Second claw supporting part 
           183 ,  283  Second claw part 
           184 ,  284  Flange part 
           190 ,  290  Base part 
           191 ,  291  Support stand 
           192 ,  292  Rotational driving part 
           193  Advance/retreat driving part 
           194  Sliding bearing member 
         B Seedbed 
       
     
       DESCRIPTION OF EMBODIMENTS 
       [0051]    Hereinbelow, a seedbed holding unit  160  as a first embodiment of the present invention will be described based on the drawings. 
         [0052]    First, it should be noted that the seedbed holding unit  160  is used by being incorporated into a plant-transplanting device  100  that transplants a seedbed B from a plant holder  110  to a cultivation pallet  120 . Specifically, the seedbed holding unit  160  is incorporated into a transferring mechanism  150  of the plant-transplanting device  100 , and transfers the seedbed B in a vertical direction while holding the seedbed B during the transfer of the seedbed B in the vertical direction. 
         [0053]    As shown in  FIG. 1 , the plant-transplanting device  100  includes the plant holder  110  in which a plurality of holder seedbed retaining parts  111  that pass through the plant holder  110  in the vertical direction and retain the seedbed B are disposed in a horizontal direction, the cultivation pallet  120  in which a plurality of pallet seedbed retaining parts  121  that pass through the cultivation pallet  120  in the vertical direction and retain the seedbed B are disposed in the horizontal direction, a holder retaining/moving mechanism  130  that retains the plant holder  110  and moves the plant holder  110  in the horizontal direction, a pallet retaining mechanism  140  that retains the cultivation pallet  120  in a fixed state, and a transferring mechanism  150  that transfers the seedbed B in the vertical direction. 
         [0054]    As shown in  FIG. 7 , in the plant-transplanting device  100  of the present embodiment, the plant holder  110  is retained at a position above the cultivation pallet  120  by the holder retaining/moving mechanism  130  and the pallet retaining mechanism  140 , the seedbed B retained by the holder seedbed retaining part  111  is lowered and inserted into the pallet seedbed retaining part  121  by the transferring mechanism  150 , and the seedbed B is thereby transplanted. 
         [0055]    Note that, conversely, the plant-transplanting device  100  may also be configured such that the plant holder  110  is retained at a position below the cultivation pallet  120 , the seedbed B retained by the holder seedbed retaining part  111  is raised and inserted into the pallet seedbed retaining part  121  by the transferring mechanism  150 , and the seedbed B is thereby transplanted. 
         [0056]    The seedbed B in the present embodiment is formed of urethane or the like and is formed into a mat-like shape in which a plurality of seedbeds B 1  each having a seed and seedling accommodating part B 2  are coupled to each other longitudinally and laterally, as shown in  FIG. 3 . Each seedbed B 1  is partially coupled to the adjacent seedbed B 1  at the central portion of each side of the seedbed B 1  with a coupling part B 3  that extends along a thickness direction of the seedbed B. Note that the specific form of the seedbed B 1  is not limited to the form described above, and the specific form thereof may be any form. 
         [0057]    Next, the transferring mechanism  150  into which the seedbed holding unit  160  of the present embodiment is incorporated will be described based on the drawings. 
         [0058]    As shown in  FIG. 1  and  FIG. 2 , the transferring mechanism  150  has a plurality of the seedbed holding units  160 , a supporting part  151  that supports the plurality of the seedbed holding units  160 , a lateral linear actuator  152  that moves the supporting part  151  in the lateral direction, and a longitudinal linear actuator  153  that moves the lateral linear actuator  152  in a longitudinal direction, adjusts the position of each seedbed holding unit  160  in the horizontal direction using the lateral linear actuator  152  and the longitudinal linear actuator  153 , and transfers the seedbed B in the vertical direction in a state in which the seedbed B is held by the seedbed holding unit  160 . 
         [0059]    As shown in  FIG. 4  to  FIG. 6 , each seedbed holding unit  160  includes a first holding member  170  and a second holding member  180  that are rotatable relative to each other about a predetermined rotation axis A, a base part  190  that supports the first holding member  170  and the second holding member  180 , and an advance/retreat driving part  193  (shown in  FIG. 2 ) that drives the base part  190  such that the base part  190  is able to advance or retreat along the vertical direction (rotation axis direction). 
         [0060]    The first holding member  170  is formed of a rigid material such as metal and, as shown in  FIG. 4  to  FIG. 6 , integrally includes a bar-shaped shaft part  171  that extends along the predetermined rotation axis A, a first claw supporting part  172  that is formed at the tip of the shaft part  171 , two first claw parts  173  that are formed on the first claw supporting part  172 , and a driven part  174  that is formed at the lower end of the shaft part  171  and engages with a rotational driving part  192  of the base part  190 . The first claw supporting part  172  has an outer edge that is circular when it is viewed in the rotation axis direction, and the two first claw parts  173  are formed at positions that oppose each other with an angle of 180° on the outer edge of the first claw supporting part  172 . 
         [0061]    The second holding member  180  is formed of a rigid material such as metal and, as shown in  FIG. 4  to  FIG. 6 , integrally includes a cylindrical pipe part  181  that extends along the rotation axis direction, a second claw supporting part  182  that is formed at the tip of the pipe part  181 , two second claw parts  183  that are formed on the second claw supporting part  182 , and a flange part  184  that is formed at the lower end of the pipe part  181  and fixed to the base part  190 . The second claw supporting part  182  has an outer edge that is circular when it is viewed in the rotation axis direction, and the two second claw parts  183  are formed at positions that oppose each other with an angle of 180° on the outer edge of the second claw supporting part  182 . As shown in  FIG. 6 , the shaft part  171  of the first holding member  170  is inserted into the pipe part  181  of the second holding member  180 . Note that, in the present embodiment, as shown in  FIG. 6 , a sliding bearing member  194  is disposed between the first holding member  170  and the second holding member  180  but, in the case where the shaft part  171  and the pipe part  181  are configured so as to slide relative to each other adequately, the installation of the sliding bearing member  194  is not necessary. 
         [0062]    As shown in  FIG. 4  and  FIG. 5 , each of the first claw part  173  and the second claw part  183  is formed such that the tip side thereof is narrower than the bottom side thereof, and an uneven nonslip part is formed on a holding surface thereof. 
         [0063]    As shown in  FIG. 4  to  FIG. 6 , the base part  190  has a support stand  191  to which the second holding member  180  is fixed, and the rotational driving part  192  that is disposed so as to be fixed to the support stand  191 . The rotational driving part  192  engages with the shaft part  171  of the second holding member  180  and rotationally drives the second holding member  180 , and is configured as an air-driven actuator in the present embodiment. Note that the specific form of the rotational driving part  192  may be any form as long as the rotational driving part causes the first holding member  170  and the second holding member  180  to rotate relative to each other, and the rotational driving part may be, e.g., an electric motor. 
         [0064]    The advance/retreat driving part  193  is configured as the air-driven actuator, and drives the base part  190  such that the base part  190  is able to advance or retreat along the vertical direction. Note that the specific form of the advance/retreat driving part  193  may be any form as long as the advance/retreat driving part drives the base part  190  such that the base part  190  is able to advance or retreat along the rotation axis direction. 
         [0065]    The seedbed holding unit  160  configured as described above holds the seedbed B using the first claw parts  173  formed on the first holding member  170  and the second claw parts  183  formed on the second holding member  180  by rotating the first holding member  170  and the second holding member  180  relative to each other about the predetermined rotation axis A using the rotational driving part  192 , and transfers the held seedbed B in the vertical direction by driving the base part  190  such that the base part  190  advances or retreats in the vertical direction using the advance/retreat driving part  193 . 
         [0066]    Next, a seedbed holding unit  260  according to a second embodiment of the present invention will be described based on  FIG. 8 . Herein, in the second embodiment, the configurations other than that of the claw part formed in the holding member are the same as those in the first embodiment described above. Accordingly, the description of the configurations other than that of the claw part will be omitted by changing the leftmost digit of each reference sign shown in the description and the drawings related to the first embodiment from 1 to 2. 
         [0067]    In the second embodiment, as shown in  FIG. 8 , four first claw parts  273  are formed at intervals of 90° on an outer edge of a first claw supporting part  272  of a first holding member  270 , and four second claw parts  283  are formed at intervals of 90° on an outer edge of a second claw supporting part  282  of a second holding member  280 . 
         [0068]    In addition, in the first embodiment, the first claw parts  173  and the second claw parts  183  are formed integrally with the first holding member  170  and the second holding member  180 . On the other hand, in the second embodiment, as shown in  FIG. 8 , the first claw parts  273  and the second claw parts  283  are formed separately from the first holding member  270  and the second holding member  280 , and are fixed to the first claw supporting part  272  and the second claw supporting part  282 . Thus, in the case where the claw parts  273  and  283  are formed separately from the holding members  270  and  280 , it becomes possible to perform usage such as replacing the claw parts  273  and  283  when the claw parts  273  and  283  are damaged or changing the type of each of the claw parts  273  and  283  in accordance with the size and shape of the seedbed B. 
         [0069]    Thus, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. 
         [0070]    For example, in the embodiments described above, the description has been made on the assumption that the seedbed holding unit is used for the transplantation of the seedbed into the cultivation pallet from the plant holder, but the specific usage of the seedbed holding unit is not limited thereto, and the usage of the seedbed holding unit may be any usage as long as the usage requires holding of the seedbed. 
         [0071]    In addition, in the embodiments described above, the description has been made on the assumption that two or four first claw parts and two or four second claw parts are provided, but the specific number of the first claw parts or the second claw parts only needs to be one or more. In the case where a plurality of the first claw parts and a plurality of the second claw parts are provided, it is preferable to dispose the claw parts at regular angle intervals on the outer edge of the claw supporting part of each holding member. 
         [0072]    Further, in the embodiments described above, the description has been made on the assumption that the seedbed is held by the first claw part and the second claw part by fixing the second holding member and rotating the first holding member, but the seedbed holding unit may be configured such that the second holding member is also rotated when the seedbed is held.