Patent Publication Number: US-9421587-B2

Title: Pallet wiping device, pallet cleaning device, and pallet work line

Description:
TECHNICAL FIELD 
     The present invention relates to a pallet wiping device, a pallet washing device, and a pallet work line. 
     BACKGROUND ART 
     Pallets formed of resin such as plastic are used for transporting goods in a variety of industries. As pallets are repeatedly used, pallets that are used a certain number of times require washing. Resin pallets are washed, for example, with water or liquid cleaner. To reuse the washed pallets, the pallets have to be dried. In a conventional pallet washing step, for example, water left on a pallet is removed with a blower. A method of promoting drying of a pallet by blowing hot air onto the pallet with a blower and a method of promoting drying after washing by heating wash water are known. A pallet washing system is also known, which dries a pallet by hot air after the pallet is centrifugally spun for dewatering (see, for example, Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent Application Laid-Open Publication No. 2010-125388 
     SUMMARY OF INVENTION 
     Technical Problem 
     A pallet includes a fork insertion hole to which a fork is inserted. 
     It is necessary to ensure that the interior of the fork insertion hole is dried after washing. With the method of centrifugally spinning a pallet for dewatering, energy consumption for a power source for spinning the pallet is large, and its cost is high. In addition, the spin of a pallet having a heavy weight is rapidly accelerated and rapidly decelerated to cause great damage to the device that spins pallets, thereby increasing the maintenance cost. With such a method, the interior of the fork insertion hole is not fully dried, and the interior of the fork insertion hole therefore has to be dried with hot air, which increases the cost for running a device such as a boiler for obtaining hot air. Even with a method of drying a pallet only with a blower, the cost required for a device such as a boiler is increased similarly. With the method of washing a pallet with heated wash water, initial cost and running cost for a heater for heating wash water, and a circulator and a filter for recycling wash water are high. 
     The present invention is made in view of the problems described above. An object of the present invention is to provide a pallet wiping device, a pallet washing device, and a pallet work line capable of drying the washed pallet reliably at low cost. 
     Solution to Problem 
     A pallet wiping device according to an aspect of the present invention promotes drying after washing of a pallet including a fork insertion hole to which a fork is inserted. The pallet wiping device includes: a wiping unit including a water-absorbing portion, an arm, and a power source; and a pallet placement unit on which the pallet is placed at a certain position such that a direction in which the fork insertion hole extends is oriented along a certain direction. The water-absorbing portion is formed of a water-absorbent material. The arm supports the water-absorbing portion and is connected to the power source. The power source moves the arm reciprocally along the certain direction while bringing the water-absorbing portion into contact with an inner wall surface of the fork insertion hole of the pallet placed on the pallet placement unit. 
     In the pallet wiping device in the embodiment above, the water-absorbing portion supported by the arm reciprocates along the direction in which the fork insertion holes extends while coming into contact with the inner wall surface of the fork insertion hole, so that water left in the fork insertion hole of the pallet after washing can be removed. Accordingly, the pallet can be dried reliably. In addition, the pallet can be dried at low cost because removal of water in the interior of the fork insertion hole is implemented by wiping water with the water-absorbent water-absorbing member without using heat. 
     In the pallet wiping device according to another aspect, the wiping unit further includes a rail that supports the arm and is provided along the certain direction. The arm is formed with a rod-like member having a cross section smaller than a size of a cross section of the fork insertion hole and having a certain length, supports the water-absorbing portion in proximity to one end, and reciprocates along the rail. 
     According to the embodiment above, the reciprocation of the arm along the rail moves the water-absorbing portion reciprocally along the direction in which the fork insertion hole extends, so that water left in the fork insertion hole of the pallet after washing can be removed reliably. 
     In the pallet wiping device according to yet another embodiment, the wiping unit has a pair of such arms spaced apart from each other by a distance corresponding to a distance between two fork insertion holes of the pallet. The pair of arms are connected by an arm coupling portion in proximity to the other ends. The arm coupling member is connected to the power source. The power source moves the arm coupling member reciprocally along the certain direction. 
     According to the embodiment above, a pair of arms are provided corresponding to two fork insertion holes of a pallet, so that water in the interior of the two fork insertion holes can be removed efficiently. 
     In the pallet wiping device according to yet another embodiment, the fork insertion hole is provided so as to pass through between parallel side surfaces of the pallet. A pair of such wiping units are arranged along the certain direction so that the pallet placement unit is interposed therebetween. The arm has a length at least half a distance between the parallel side surfaces of the pallet. 
     According to the embodiment above, when compared with a case where one wiping unit is provided on either one side surface of a pallet, the wiping unit can be provided with a shorter arm, so that the distance over which the arm reciprocates can be reduced. In addition, the rigidity required for the material of the arm is low. Accordingly, the wiping unit can be configured in a small size. 
     In the pallet wiping device according to yet another embodiment, the water-absorbing portion may be formed with a ground fabric made of cloth and water-absorbent pile provided at least one side surface of the ground fabric. The ground fabric may be provided so as to cover one end of the arm. 
     Cloth having water-absorbent pile is preferred for the water-absorbing portion because of large water absorbency. According to this embodiment, more suitable water absorbency can be obtained. 
     Since the pile is flexible, the water-absorbing portion has a good contact property to the inner wall portion of the fork insertion hole to be wiped. 
     In the pallet wiping device according to yet another embodiment, the water-absorbing portion is made of cloth. The water-absorbing portion is provided so as to cover one end of the arm. According to the embodiment above, the cost for the water-absorbing portion can be reduced. 
     In the pallet wiping device according to yet another embodiment, the pallet placement unit is provided with a stacker that is a device for stacking pallets. According to this embodiment, the dried pallets can be neatly stacked. 
     In the pallet wiping device according to yet another embodiment, the wiping unit further includes an air blowing device that outputs air toward the water-absorbing portion. This embodiment can promote evaporation of water contained in the water-absorbing portion as a result of wiping pallets. Accordingly, in a case where one water-absorbing portion is repeatedly used to wipe a plurality of pallets until the water absorbency is deteriorated, the number of pallets to be wiped can be increased. 
     A pallet washing device according to an embodiment of the present invention is provided for washing a pallet. The pallet washing device includes a washing unit that washes a pallet with water, the pallet wiping device as described above provided at a stage subsequent to the washing unit, and a conveyance unit that conveys a pallet washed in the washing unit to the pallet placement unit of the pallet wiping device. 
     The pallet wiping device is provided at a stage subsequent to the washing unit, whereby the washed pallet can be dried reliably with the pallet wiping device. A preferred pallet washing device is thus configured. 
     The pallet wiping device according to another embodiment further includes a stacker that stacks pallets, and wiping means. The stacker includes a supporter that supports a bottom pallet of one or more stacked pallets at a position at a certain height, and a lifter including a table on which a pallet to be stacked is placed. The lifter is capable of raising and lowering the pallet to be stacked with the pallet being placed on the table. The wiping means is provided in the stacker so as to abut on a side surface of a pallet raised by the lifter for cleaning the side surface of the pallet. The lifter raises the pallet to be stacked to a position where an upper surface of the pallet to be stacked comes into contact with a lower surface of the bottom pallet, and further raises the pallet to be stacked and the stacked pallets put on the pallet to be stacked until the pallet to be stacked reaches the position at a certain height. The supporter supports the pallet to be stacked that is raised by the lifter, at the position at a certain height. The table of the lifter is included in the pallet placement unit. 
     In the embodiment above, the pallet wiping device includes a stacker for stacking pallets. In this stacker, the stacked pallets are raised in a state in which they are put on a pallet to be stacked. The wiping means is provided so as to abut on the side surface of the raised pallet, so that the pallet side surface is raised in contact with the wiping means whereby dirt, dust, and the like on the side surface of the pallet are removed. Such a configuration is implemented by simply providing the wiping means in the stacker and does not require a special operation mechanism other than the stacker. Accordingly, pallets can be cleaned readily at low cost. 
     The pallet wiping device according to yet another embodiment further includes an unstacker that unstacks a plurality of stacked pallets one by one, and wiping means. The unstacker includes a supporter that supports a bottom pallet of one or more stacked pallets at a position at a certain height, and a lifter including a table on which a pallet is placed. The lifter is capable of raising and lowering a pallet with the pallet being placed on the table. The wiping means is provided in the unstacker so as to abut on a side surface of a pallet lowered by the lifter for cleaning the side surface of the pallet. The supporter releases support to the bottom pallet in a state in which the lifter supports a lower surface of the bottom pallet from below with the table. The lifter lowers the stacked pallets until a pallet immediately above the bottom pallet of the stacked pallets reaches the position at a certain height. The supporter supports the pallet immediately above the bottom pallet. The lifter lowers the bottom pallet to a certain position with the bottom pallet being placed on the table. The table of the lifter is included in the pallet placement unit. 
     In the embodiment above, the pallet wiping device includes an unstacker for unstacking the stacked pallets. In this unstacker, when the bottom pallet of the stacked pallets is unstacked, the stacked pallets are lowered by the lifter. The wiping means is provided so as to abut on the side surface of the lowered pallet, so that the pallet side surface is lowered in contact with the wiping means whereby dirt, dust, and the like on the side surface of the pallet are removed. Such a configuration is implemented by simply providing the wiping means in the unstacker and does not require a special operation mechanism other than the unstacker. Accordingly, pallets can be cleaned readily at low cost. 
     The pallet wiping device according to yet another embodiment further includes a feed line at the table in the lifter of the stacker for moving a pallet to be stacked and placing the moved pallet onto the table. The feed line includes upper surface wiping means provided so as to abut on an upper surface of the pallet moved to the table for cleaning the upper surface of the pallet, and lower surface wiping means provided so as to abut on a lower surface of the pallet for cleaning the lower surface of the pallet. 
     According to the embodiment above, a feed line for feeding a pallet to be stacked into the stacker is provided. The pallet is moved on this line. The upper surface wiping means and the lower surface wiping means are provided so as to abut on the upper surface and the lower surface of the moved pallet, so that the pallet is moved with the upper surface and the lower surface thereof in contact with the upper surface wiping means and the lower surface wiping means, whereby dirt, dust, and the like on the upper surface and the lower surface of the pallet are removed. Such a configuration is implemented by simply providing the wiping means in the feed line and does not require a special operation mechanism other than the feed line. Accordingly, pallets can be cleaned readily at low cost. 
     The pallet wiping device according to yet another embodiment further includes an ejection line for moving a pallet unstacked from a plurality of stacked pallets by the unstacker and placed onto the table of the lifter and for ejecting the moved pallet from the unstacker. The ejection line includes upper surface wiping means provided so as to abut on an upper surface of the pallet moved from the table to be ejected from the unstacker for cleaning the upper surface of the pallet, and lower surface wiping means provided so as to abut on a lower surface of the pallet for cleaning the lower surface of the pallet. 
     According to the embodiment above, an ejection line for ejecting a pallet unstacked by the unstacker is provided. The pallet is moved on this line. The upper surface wiping means and the lower surface wiping means are provided so as to abut on the upper surface and the lower surface of the moved pallet, so that the pallet is moved with the upper surface and the lower surface thereof in contact with the upper surface wiping means and the lower surface wiping means, whereby dirt, dust, and the like on the upper surface and the lower surface of the pallet are removed. Such a configuration is implemented by simply providing the wiping means in the ejection line and does not require a special operation mechanism other than the ejection line. Accordingly, pallets can be cleaned readily at low cost. 
     A pallet work line according to an embodiment of the present invention includes a first pallet wiping device that is the pallet wiping device as described above including an unstacker, and receives one or more stacked pallets and outputs an unstacked pallet to a subsequent stage, a work line that performs a certain procedure on the pallet output from the first pallet wiping device and outputs the pallet to a subsequent stage, and a second pallet wiping device that is the pallet wiping device as described above including a stacker, and stacks the pallet output from the work line and outputs a plurality of stacked pallets to a subsequent stage. 
     In the pallet work line in this embodiment, a work line is provided at a stage subsequent to the first pallet cleaning device configured to include an unstacker, so that a certain procedure can be performed on the cleaned pallet. Accordingly, the working efficiency for a certain procedure is improved. The second pallet cleaning device configured to include a stacker is provided at a stage subsequent to the work line, so that the pallet that has been subjected to a certain procedure is cleaned. Accordingly, the pallets that have been subjected to a certain procedure can be output to a subsequent stage in a state in which they are cleaned and stacked. 
     In the pallet work line according to another embodiment,. the wiping means of the first pallet cleaning device is formed of a material capable of absorbing a dust absorber, a dust absorber having an ability to chemically absorb dust. The wiping means of the second pallet cleaning device is formed of a water-absorbent material. 
     According to the embodiment above, the pallet cleaned fully enough to perform a certain procedure can be provided to the work line, and the fully cleaned pallets in a stack are output to a subsequent stage. 
     Advantageous Effects of Invention 
     According to the present invention, the washed pallet can be dried reliably at low cost. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a pallet wiping device. 
         FIG. 2  is a perspective view of a pallet. 
         FIGS. 3A and 3B  are a top view and a side view of a wiping unit of the pallet wiping device, respectively. 
         FIGS. 4A and 4B  are a top view and a side view of the wiping unit of the pallet wiping device, respectively. 
         FIG. 5  is a perspective view of an arm and a water-absorbing portion. 
         FIGS. 6A and 6B  are diagrams illustrating operation of the arm and the water-absorbing portion. 
         FIG. 7  is a diagram illustrating a state in which the arm and the water-absorbing portion are inserted in a fork insertion hole of a pallet. 
         FIG. 8  is a perspective view of a pallet washing device. 
         FIG. 9  is a diagram illustrating an example of the pallet wiping device with an air blowing device. 
         FIG. 10  is a perspective view of a pallet cleaning device. 
         FIGS. 11A and 11B  are diagrams illustrating operation of an unstacker. 
         FIGS. 12A and 12B  are diagrams illustrating operation of the unstacker. 
         FIG. 13  is a diagram illustrating operation of the unstacker. 
         FIGS. 14A and 14B  are diagrams illustrating operation of a stacker. 
         FIGS. 15A and 15B  are diagrams illustrating operation of the stacker. 
         FIG. 16  is a diagram illustrating operation of the stacker. 
         FIGS. 17A and 17B  are diagrams illustrating cleaning of a pallet in a pallet cleaning device including the unstacker. 
         FIGS. 18A and 18B  are diagrams illustrating cleaning of a pallet in a pallet cleaning device including the stacker. 
         FIG. 19  is a schematic diagram illustrating a pallet work line. 
         FIG. 20  is a perspective view of a pallet wiping device including a configuration of part of the pallet cleaning device. 
         FIG. 21  is a schematic diagram illustrating a pallet work line including the pallet wiping device shown in  FIG. 20 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of a pallet wiping device, a pallet washing device, and a pallet work line according to the present invention will be described in detail below with reference to the figures. It is noted that in the figures, the same or corresponding parts are denoted with the same reference signs. 
     First Embodiment 
     A pallet wiping device  1  in the present embodiment is shown in  FIG. 1 .  FIG. 1  is a perspective view of the pallet wiping device  1 . The pallet wiping device  1  is a device that promotes drying after washing of a pallet P having a fork insertion hole to which a fork is inserted. The pallet wiping device  1  includes a wiping unit  10  and a pallet placement unit  30 , as shown in  FIG. 1 . 
     The wiping unit  10  is a unit that wipes water left in the fork insertion hole of the pallet P placed on the pallet placement unit  30 . The wiping unit  10  has a water-absorbing portion  11 , an arm  12 , and a cylinder  13  as a power source. The detailed configuration of the wiping unit  10  will be described later with reference to  FIG. 3  and  FIG. 4 . The pallet placement unit  30  is a unit on which a pallet P is placed. 
     Referring now to  FIG. 2 , an example of a pallet P to be cleaned in the present embodiment will be described.  FIG. 2  is a perspective view of a pallet P. As shown in  FIG. 2 , the pallet P has an upper surface P 1  that forms an approximately square main surface on which a cargo is put, an approximately square lower surface P 5  opposed to the upper surface P 1 , and two sets of opposing side surfaces P 2 , P 3 . The pallet P is also provided with fork insertion holes P 4  passing through the opposing side surfaces P 3 . The upper surface P 1  of the pallet P is formed with a deck portion on the top surface side of the pallet P. The lower surface P 5  of the pallet P is formed with a deck portion on the back surface side of the pallet P. 
     Referring to  FIG. 1  again, the configuration of the pallet placement unit  30  will be described. The pallet placement unit  30  has a base  300 , a table  301 , rotation shaft portions  302 A and  302 B, gear portions  303 A and  303 B, a motor  304 , a drive chain  305 , and a pallet feeding chain  306 . 
     The base  300  is configured such that four pillar-like members arranged at vertices of a rectangle as viewed from above and beam members coupling the pillar-like members to each other form a frame in which the table  301  is provided. 
     The table  301  is provided such that a pair of rectangular plate-like members, each having a longitudinal length approximately equivalent to the length of one side of the deck portion of the pallet P, are opposed to and spaced apart from each other on the base  300 . In the present embodiment, the pallet P is placed on the table  301  such that the direction in which the fork insertion hole P 4  extends is orthogonal to the longitudinal direction of the table  301 . 
     At one end and the other end of a surface of the table  301  that faces the opposing direction, the gear portions  303 A and  303 B that can rotate about the opposing direction are provided. The pallet feeding chain  306  is suspended between the gear portion  303 A and the gear portion  303 B. The opposing gear portions  303 A are coupled to each other by the rotation shaft portion.  302 A. The opposing gear portions  303 B are coupled to each other by the rotation shaft portion  302 B. 
     The motor  304  is provided at the base  300  to start and stop operation in accordance with an operation instruction input from a controller (not shown). The rotation shaft portion  302 A is coupled through the drive chain  305  so as to be able to be driven by the motor  304 . The motor  304  is operated to rotate the rotation shaft portion  302 A about the opposing direction of the table  301 , so that the gear portions  303 A coupled to the rotation shaft portion  302 A are further rotated. The pallet feeding chain  306  is then driven in the longitudinal direction of the table  301 . Accordingly, when the pallet wiping device  1  is configured as part of the pallet washing device, the pallet P can be easily received from a stage previous to the pallet wiping device  1  and output to a stage subsequent to the pallet wiping device  1 . 
     In the example shown in  FIG. 1 , the pallet wiping device  1  places the pallet P conveyed by a conveyor C onto the table  301 . When the pallet P is placed onto the table  301 , the pallet P is aligned, for example, by a stopper (not shown) provided in proximity to an end of the table  301  that is opposite to the direction in which the conveyor C is provided, as viewed from the pallet placement unit  30 . This enables accurate insertion of the water-absorbing portion  11  and the arm of the wiping unit  10  into the fork insertion hole P 4 . 
     Referring now to  FIG. 3  and  FIG. 4 , the detailed configuration of the wiping unit  10  will be described.  FIG. 3A  is a top view of the wiping unit  10  in a first state.  FIG. 3B  is a side view of the wiping unit  10  in the first state.  FIG. 4A  is a top view of the wiping unit  10  in a second state.  FIG. 4B  is a side view of the wiping unit  10  in the second state. The first state and the second state are states at different timings in the process of reciprocation of the arm  12 . In the first state, the arm  12  is furthest from the pallet placement unit  30 . In the second state, the arm  12  is closest to the pallet placement unit  30 , and the water-absorbing portion  11  is inserted into the fork insertion hole P 4  of the pallet P. 
     The wiping unit  10  has a base  15  for supporting the water-absorbing portion  11 , the arm  12 , and the cylinder  13 . The base  15  is configured such that four pillar-like members arranged at vertices of a rectangle as viewed from above and beam members coupling the pillar-like members to each other form a frame in which the portions  11  to  14  are provided. 
     The wiping unit  10  has a rail  14  provided on the beam members of the base  15  and facing upward. The rail  14  is a member that guides the arm  12  such that the arm  12  reciprocates in the direction in which the fork insertion hole P 4  extends. The rail  14  supports the arm  12  and is provided along the direction in which the fork insertion hole P 4  extends. The arm  12  is supported on the rail  14  so as to be able to reciprocate along the direction in which the rail  14  extends. 
     The arm  12  is formed of a rod-like member having a cross section smaller than the size of the cross section of the fork insertion hole P 4  and having a certain length. In the present embodiment, the arm  12  includes two rod-like members provided parallel to and spaced apart from each other along the direction in which the fork insertion hole P 4  extends. The arm  12  in the present invention is not limited to the manner in the foregoing embodiment. The distance between the two rod-like members of the arm  12  is set to a length corresponding to the cross-sectional shape and size of the fork insertion hole P 4 . In the present embodiment, since the cross section of the fork insertion hole P 4  has a rectangular shape having a longitudinal direction along the horizontal direction, the distance between the two rod-like members of the arm  12  corresponds to the length of the longitudinal side of the rectangular shape of the cross section of the fork insertion hole P 4 . 
     The arm  12  has the water-absorbing portion  11  supported in proximity to one end. A pair of such arms  12  are provided for one wiping unit  10  so as to be spaced apart from each other by a distance corresponding to the distance between two fork insertion holes P 4  of the pallet P. The pair of arms  12  are coupled by an arm coupling member  12   a  in proximity to the other ends. The arm coupling member  12   a  is a rectangular plate-like member having a longitudinal direction set to a length corresponding to the distance between the fork insertion holes P 4 . The arm coupling member  12   a  is connected to a front end  13   a  of a rod  13   b  of the cylinder  13 . 
     The cylinder  13  is a power source to move the arm  12  in a reciprocal manner along the direction in which the fork insertion hole P 4  extends, while bringing the water-absorbing portion  11  into contact with the inner wall surface of the fork insertion hole P 4 . The cylinder  13  is provided with, for example, an air cylinder that operates pneumatically. The cylinder  13  moves the rod  13   b  reciprocally in accordance with an operation instruction input from a controller (not shown). Specifically, the arm  12  is reciprocated by the cylinder  13 , so that the wiping unit  10  alternately exhibits the manner shown in  FIG. 3  and the manner shown in  FIG. 4 . 
     Since the arm  12  is connected to the rod  13   b , the cylinder  13  moves the arm  12  reciprocally along the rail  14  through the reciprocation of the rod  13   b . In the present invention, the power source for reciprocating the arm  12  is not limited to the cylinder  13  shown in the present embodiment. The power source may be, for example, a rodless cylinder or may be any other power generator that can move the arm  12  reciprocally. 
     The water-absorbing portion  11  is a portion for removing water left in the inner wall portion of the fork insertion hole P 4  of the pallet P after washing and is formed of a water-absorbent material.  FIG. 5  is a perspective view of the arm and the water-absorbing portion. The water-absorbing portion  11  is formed with a ground fabric  11  a made of cloth and water-absorbent pile  11   b  provided on at least one side surface of the ground fabric  11   a . The ground fabric  11   a  is provided so as to cover one end of the arm  12 . The pile  11   b  is water absorbent and therefore can absorb water left on the inner wall surface of the fork insertion hole P 4 . The pile  11   b  is elastic and therefore easily allows the water-absorbing portion  11  to come into intimate contact with the inner wall portion of the fork insertion hole P 4  when the arm  12  reciprocates along the direction in which the fork insertion hole P 4  extends. In the present embodiment, the water-absorbing portion  11  is formed with the ground fabric  11   a  and the pile  11   b . The present invention, however, is not limited thereto. For example, the water-absorbing portion  11  may be formed of only water-absorbent cloth. In this case, the water-absorbing portion  11  can be formed at low cost. 
     Referring now to  FIG. 6 , the operation of the arm  12  and the water-absorbing portion  11  will be described.  FIG. 6A  is a diagram illustrating a state in which the arms  12  and the water-absorbing portions  11  are not inserted into the fork insertion holes P 4 . This state corresponds to the state shown in  FIG. 3 .  FIG. 6B  is a diagram illustrating a state in which the arms  12  and the water-absorbing portions  11  are inserted into the fork insertion holes P 4 . This state corresponds to the state shown in  FIG. 4 . Specifically, through the operation of the cylinder  13 , the arms  12  and the water-absorbing portions  11  are moved from the position shown in  FIG. 6A  to the position shown in  FIG. 6B . Through the subsequent operation of the cylinder  13 , the arms  12  and the water-absorbing portions  11  are moved from the position shown in  FIG. 6B  to the position shown in  FIG. 6A . As a result of such movements, the water-absorbing portions  11  are inserted/removed into/from the fork insertion holes P 4  while coming into contact with the inner wall surfaces of the fork insertion holes P 4 , so that water left on the inner wall surfaces of the fork insertion holes P 4  are absorbed in the water-absorbing portions  11 . In order to remove water left on the inner wall surfaces of the fork insertion holes P 4 , the arms  12  and the water-absorbing portions  11  are reciprocated at least once. 
     In the case where a pair of wiping units  10  are provided along the direction in which the fork insertion hole P 4  extends, with the pallet placement unit  30  interposed therebetween, as shown in  FIG. 1 , the arm  12  preferably has a length at least half the distance between the parallel side surfaces of the pallet P. In this case, as shown in  FIG. 6B , the opposing water-absorbing portions  11  are moved to the position where the water-absorbing portions  11  come into contact with each other in proximity to the center in the direction in which the fork insertion hole P 4  extends, so that the water-absorbing portions  11  can be moved in contact with the entire inner wall surfaces of the fork insertion holes P 4 . Accordingly, water can be removed from the entire region of the interior of the fork insertion hole P 4 . The operation of the cylinder  13  may be controlled such that the timings at which the opposing water-absorbing portions  11  move from the position shown in  FIG. 6A  to the position shown in  FIG. 6B  do not match. In this case, even when the accuracy of alignment of a pair of wiping units  10  is not enough, collision of the opposing water-absorbing portions  11  can be avoided. 
       FIG. 7  is a diagram illustrating a state in which the arm  12  and the water absorption potion  11  are inserted into the fork insertion hole P 4  of the pallet P. As shown in  FIG. 7 , the water-absorbing portion  11  in the present embodiment is provided with the ground fabric  11  a and the pile  11   b . The pile  11   b  is yarn having a certain thickness and length, and is water absorbent and flexible. Because of the flexibility of the pile  11   b , even if the arm  12  that supports the water-absorbing portion  11  is not strictly aligned with the fork insertion hole P 4 , as long as the alignment has a certain degree of accuracy, the water-absorbing portion  11  can reciprocate with the pile  11   b  coming into contact with the inner wall surface of the fork insertion hole P 4  while having the cross section changed, as viewed from the direction in which the fork insertion hole P 4  extends. 
     A pallet washing device including the pallet wiping device  1  in the present embodiment will now be described.  FIG. 8  is a perspective view of a pallet washing device  50 . The pallet washing device  50  includes a side shower S 1  and a mist shower S 2  as washing units for washing a pallet, as shown in  FIG. 8 . 
     The side shower S 1  is a device for washing the side surfaces P 2  and P 3  and the inside of the fork insertion holes P 4  of the pallet P with water, and sprays water from the side of the pallet P. The mist shower S 2  is a device for washing the deck portion of the pallet P, and sprays water from above the pallet P and removes contamination of the pallet with a brush provided at the same position. 
     The pallet washing device  50  also includes a top surface dewatering wiper W 1 , high-pressure blowers B 1 , B 2 , and B 3 , and a back surface dewatering wiper W 2  as means for removing water left on the pallet P. The pallet washing device  50  further includes a conveyor C as a conveyance unit that conveys the pallet P from the washing unit to the water removing means and the pallet wiping device  1 . 
     The top surface dewatering wiper W 1  and the back surface dewatering wiper W 2  remove water left on the deck portion on the top surface side and the deck portion on the back surface side of the pallet P. The high-pressure blowers B 1 , B 2 , and B 3  are devices that remove water left on the pallet P by blowing high-pressure air to the pallet, and blow high-pressure air to the upper surface, the lower surface, and the side surface, respectively, of the pallet. 
     The high-pressure blower B 3  is provided to remove water in the interior of the fork insertion hole P 4 . The high-pressure blower B 3 , however, cannot fully remove water in the interior of the fork insertion hole P 4 . In the pallet washing device  50  in the present embodiment, the pallet wiping device  1  is provided at a stage subsequent to the washing unit, so that water left in the interior of the fork insertion hole P 4  can be fully removed. 
     At a stage subsequent to the pallet wiping device  1  in the pallet washing device  50 , devices for carrying out other processes may be provided as necessary. For example, a line for checking for breakage of pallets P, a stacker as a device for piling up pallets P, and the like can be provided at a stage subsequent to the pallet wiping device  1 . 
     As described above, in the pallet wiping device  1  in the present embodiment, the water-absorbing portion  11  supported by the arm  12  reciprocates along the direction in which the fork insertion hole P 4  extends, while coming into contact with the inner wall surface of the fork insertion hole P 4 , whereby water left in the fork insertion hole P 4  of the pallet P after washing can be removed. Accordingly, the pallet can be dried reliably. In addition, the pallet P can be dried at low cost because removal of water in the interior of the fork insertion holes P 4  is implemented by wiping water with the water-absorbent water-absorbing portion  11  without using heat. 
     The pallet wiping device  1  in the present embodiment has a configuration in which the pallet P is placed on the pallet placement unit  30  with the upper surface P 1  of the pallet P oriented approximately horizontally. The present invention, however, is not limited to this configuration. For example, the pallet wiping device  1  may have a configuration in which the pallet P is placed on the pallet placement unit  30  with the upper surface P 1  of the pallet P oriented approximately vertically. In this case, a pair of arms  12  of the wiping unit  10  may be arranged to be spaced apart from each other in the approximately vertical direction in accordance with the arrangement of the fork insertion holes P 4 . 
     In the present embodiment, water left in the fork insertion hole P 4  of the pallet P placed on the pallet placement unit  30  is removed. This pallet placement unit  30  may be provided with, for example, a stacker for piling up pallets P. Specifically, the pallet wiping device  1  can include a stacker in place of the pallet placement unit  30  shown in the figure, at the position where the pallet placement unit  30  in  FIG. 1  is provided. 
     The stacker includes a pallet receiving unit and a pallet stacking unit provided above the pallet receiving unit. The pallet receiving unit is a unit that receives a pallet conveyed by the conveyor C and on which the received pallet is placed. The pallet receiving unit has a function equivalent to the pallet placement unit  30  shown in  FIG. 1 . Specifically, the wiping unit  10  can remove water left in the fork insertion hole P 4  of the pallet P placed on the pallet receiving unit. 
     The pallet receiving unit has a mechanism that raises the placed pallet P to the position where the pallet stacking unit is provided, while supporting the pallet P. The pallet stacking unit has a mechanism that supports a plurality of stacked pallets. The pallet stacking unit can support the pallet raised by the pallet receiving unit and stack pallets by putting the raised pallet under the stacked pallets already supported. As described above, the pallet placement unit  30  can be configured as a stacker so that the washed and dried pallets P can be neatly stacked. 
     The pallet wiping device  1  in the present embodiment may further include an air blowing device for drying the water-absorbing portion  11  containing water as a result of wiping pallets.  FIG. 9  is a diagram illustrating an example of the pallet wiping device with an air blowing device  16 . In the example shown in  FIG. 9 , the wiping unit  10  includes the air blowing device  16  that outputs air toward the water-absorbing portion  11 . The air blowing device  16  is coupled, for example, to the rail  14  with an air outlet facing the water-absorbing portion  11 . However, the position where the air blowing device  16  is provided is not limited thereto as long as the air output from the air blowing device  16  is directed to the water-absorbing portion  11 . Since a pair of arms  12  and a pair of water-absorbing portions  11  are provided corresponding to two fork insertion holes P 4  of the pallet P, it is preferable that a pair of air blowing devices  16  should be provided so as to be able to output air toward a pair of water-absorbing portions  11 . This air blowing device  16  is provided with a device, for example, such as a blower. As described above, the provision of the air blowing device  16  can promote evaporation of water contained in the water-absorbing portion  11  as a result of wiping pallets. Accordingly, in a case where one water-absorbing portion  11  is repeatedly used to wipe a plurality of pallets until the water absorbency is deteriorated, the number of pallets that can be wiped can be increased. 
     Second Embodiment 
     Referring to  FIG. 10  to  FIG. 19 , an embodiment of a pallet cleaning device and a pallet work line as a second embodiment will be described in detail below. 
     A pallet cleaning device  100  in the present embodiment is shown in  FIG. 10 .  FIG. 10  is a perspective view of the pallet cleaning device  100 . The pallet cleaning device  100  includes a stacker/unstacker  2  and a wiping unit  4  as shown in  FIG. 10 . The stacker is a device that stacks pallets. The unstacker is a device that unstacks a plurality of stacked pallets one by one. The stacker and the unstacker have the same configuration and operate at different timings to implement the function as a stacker or an unstacker. Therefore, these devices are illustrated in a single drawing in  FIG. 10 . 
     The stacker and the unstacker are well-known devices in the art to which the present invention belongs. The stacker and the unstacker described in the present embodiment are illustrated as an example of devices applicable to the present invention and are not intended to exclude the application of devices other than the stacker and the unstacker shown in the present embodiment. 
     The stacker/unstacker  2  includes a supporter  21 , a lifter  22 , a frame  24 , and a pallet transfer  25 . 
     The supporter  21  is a portion that supports the bottom pallet of one or more stacked pallets at a position at a certain height. 
     The supporter  21  includes, for example, two sets of, four in total, rod-like members which are arranged in pairs to be opposed to each other at a position at a certain height of the frame  24  so as to extend in a first direction along the horizontal direction. The rod-like members are designed to be inserted into the four fork insertion holes of the pallet so as to support the pallet. In the stacker/unstacker  2 , therefore, a pallet is arranged such that the direction in which the fork insertion hole extends is orientated along the first direction. 
     The rod-like members that constitute the supporter  21  are provided to be able to reciprocate between the first position and the second position along the first direction dr 1  by certain drive means (not shown). The certain drive means may be, for example, a hydraulic drive mechanism, an electric drive mechanism, or any other similar mechanism. The supporter  21  is arranged and driven in the first position such that the distance between the tip ends of the opposing rod-like members is smaller than the length of one side of the upper surface of the approximately rectangular shape of a stack of pallets arranged in the stacker/unstacker  2 . The supporter  21  is arranged and driven in the second position such that the distance between the tip ends of the opposing rod-like members is greater than the length of one side of the upper surface of the approximately rectangular shape of a stack of pallets arranged in the stacker/unstacker  2 . The supporter  21  is arranged and driven in this manner, whereby the supporter  21  supports a stack of pallets in the first position and release support to a stack of pallets in the second position. 
     The lifter  22  includes a table  23  on which a pallet is placed, and has drive means (not shown) for raising/lowering the table  23  such that the pallet placed on the table  23  can be raised/lowered. This drive means may employ any driving system such as a hydraulic system and an electric system. 
     The frame  24  is configured, for example, such that four pillar-like members arranged at vertices of an approximately square shape as viewed from above and beam members coupling these pillar-like members to each other form a frame, as shown in  FIG. 10 . 
     The frame  24  is positioned such that, of the four beam members, a set of opposing two beam members extends in the first direction and the other set of two beam members extends in the second direction dr 2  orthogonal to the first direction dr 1 , and is placed on the ground. The approximately square shape as viewed from above that is formed with the frame has a size large enough to receive a pallet P. The lifter  22  is provided within this frame. 
     In the case of the stacker, the pallet transfer  25  is a device that receives a pallet to be stacked in the frame  24  of the stacker and arranges the pallet above the table  23  of the lifter  22 . In the case of the unstacker, the pallet transfer  25  is a device that discharges a pallet, unstacked and placed onto the pallet transfer  25  by the lifter  22 , to the outside of the frame  24 . The movement of pallets such as reception and discharge of pallets is implemented by, for example, a chain conveyor provided on the upper surface thereof. The chain conveyor is configured to be able to move the placed pallet along the second direction. 
     The detailed operation of the stacker/unstacker  2  will be described later with reference to  FIGS. 11 to 16 . 
     The wiping unit  4  is a unit that cleans a side surface of a pallet and is provided in the stacker/unstacker  2  so as to abut on the side surface of a pallet raised or lowered by the lifter  22 . Specifically, the wiping unit  4  is provided with, for example, a core provided at the frame  24  so as to extend in the first direction dr 1 , and a mop covering the core. The one that covers the core is formed of any material that can clean pallets, and, for example, cloth or sponge can be applied. 
     In the case of the stacker, a pallet to be stacked and a stack of pallets put above the pallet to be stacked are raised by the lifter  22 . In the case of the unstacker, a stack of pallets are lowered by the lifter  22 . The wiping unit  4  is provided at a position where the wiping unit  4  can abut on any one of the side surfaces of the pallet raised or lowered in this manner. 
     In the example shown in  FIG. 10 , a pair of wiping units  4  are arranged to be opposed to each other so as to abut on the side surfaces orthogonal to the second direction dr 2  of the bottom pallet of a stack of pallets supported by the supporter  21 . The arrangement position of the wiping unit  4  is not limited to the position in contact with the bottom pallet, and may be any position where the wiping unit  4  can abut on a side surface of the pallet raised or lowered by the lifter unit  22 . The arrangement position of the wiping unit  4  may be such a position where the wiping unit  4  can abut on a side surface of a pallet that is orthogonal to the first direction dr 1 . 
     The wiping unit  4  is provided at a position in contact with the pallet side surface to be cleaned while acting a certain pressure. Here, the pressure acting on the side surface of the pallet may be set in a design, considering, for example, the physical properties of the material that forms the wiping unit  4 . 
     Referring now to  FIGS. 11 to 13 , the operation of an unstacker  2 A that is included in the pallet cleaning device  100  in the present embodiment will be described in detail.  FIGS. 11 to 13  are diagrams for explaining the operation of the unstacker and therefore do not show the wiping unit  4 .  FIG. 11A  is a diagram illustrating a state in which a stack of pallets P S  are supported by a supporter  21 A. The operation of unstacking one pallet P O  starting from this state is described. As shown in  FIG. 11A , the supporter  21 A supports the bottom pallet P O  of the stack of pallets P S  by positioning the rod-like members of the supporter  21 A at the first position. 
     In the next  FIG. 11B , a table  23 A of a lifter  22 A is raised from the state shown in  FIG. 11A  so that the table  23 A supports the lower surface of the bottom pallet P O  from below. Here, since the stack of pallets P S  are raised by the table  23 A from the position shown in  FIG. 11A , the mass of the stack of pallets P S  does not act on the supporter  21 A. 
     Next, in  FIG. 12A , the supporter  21 A is moved to the second position. The stack of pallets P S  become ready to be lowered, and the bottom pallet P O  is released from support by the supporter  21 A. In this state, as shown in  FIG. 12B , the lifter  22 A lowers the stack of pallets P S  until a pallet P N  immediately above the bottom pallet P O  of the stack of pallets P S  reaches a position at a certain height where the supporter  21 A is provided. The supporter  21 A is then moved to the first position again to support the pallet P N . 
     As shown in  FIG. 13 , the lifter  22 A then further lowers the pallet P O  to place the pallet P O  onto the pallet transfer  25 A. Through the operation as described above, one pallet P O  is unstacked from the stack of pallets P S . 
     Referring now to  FIGS. 14 to 16 , the operation of a stacker  2 B that is included in the pallet cleaning device  100  in the present embodiment will be described in detail.  FIGS. 14 to 16  are diagrams for explaining the operation of the stacker  2 B and therefore do not show the wiping unit  4 .  FIG. 14A  illustrates a state in which a stack of pallets P S  are supported by a supporter  21 B and a pallet P I  to be stacked is placed on a pallet transfer  25 B. The operation of stacking the pallet P I  starting from this state is described. As shown in  FIG. 14A , the supporter  21 B supports the bottom pallet P of the stack of pallets P S  by positioning the rod-like members of the supporter  21 B at the first position. 
     In the next  FIG. 14B , a lifter  22 B raises the pallet P I  to a position where the upper surface P 1  of the pallet P I  to be stacked comes into contact with the lower surface of the bottom pallet of the stack of pallets P S , and further raises the pallet P I  until the mass of the stack of pallets P S  does not act on the supporter  21 B. 
     In  FIG. 15A , the supporter  21 B is then moved to the second position. The stack of pallets P S  then become ready to be raised. In this state, as shown in  FIG. 15B , the lifter  22 B raises the stack of pallets P S  and the pallet P I  until the pallet P I  to be stacked reaches a position at a certain height where the supporter  21 B is provided. The supporter  21 B is then moved to the first position again to support the pallet P I . 
     As shown in  FIG. 16 , the lifter  22 B then lowers the table  23 B, and the supporter  21 B supports the pallet P I  together with the pallets P S . Through the operation as described above, the pallet P I  is stacked. 
     Referring now to  FIG. 17 , cleaning of pallets in a pallet cleaning device  100 A including the unstacker  2 A will be described.  FIG. 17A  is a diagram illustrating a state of pallets P and the lifter  22 A when the unstacker  2 A is in a state shown in  FIG. 11B .  FIG. 17B  is a diagram illustrating a state of pallets P and the lifter  22 A when the unstacker  2 A is in a state shown in  FIG. 12B . 
     When the unstacker  2 A changes from the state shown in  FIG. 17A  to the state shown in  FIG. 17B , the table  23 A of the lifter  22 A is lowered, whereby the bottom pallet P O  of the stack of pallets is lowered with the side surfaces P 2  coming into contact with wiping units  4 A. 
     Accordingly, contamination such as dirt and dust on the side surfaces P 2  of the pallet P O  is cleaned by the wiping units  4 A. 
     Referring now to  FIG. 18 , cleaning of pallets in a pallet cleaning device  100 B including the stacker  2 B will be described.  FIG. 18A  is a diagram illustrating a state of pallets P and the lifter  22 B when the stacker  2 B is in the state shown in  FIG. 14B .  FIG. 18B  is a diagram illustrating a state of pallets P and the lifter  22 B when the stacker  2 B is in the state shown in  FIG. 15B . 
     When the stacker  2 B changes from the state shown in  FIG. 18A  to the state shown in  FIG. 18B , the table  23 B of the lifter  22 B is raised, whereby the bottom pallet P of the stack of pallets is raised with the side surfaces P 2  coming into contact with wiping units  4 B. Accordingly, contamination such as dirt and dust on the side surfaces P 2  of the bottom pallet P of the stack of pallets is cleaned by the wiping units  4 B. 
     A pallet work line including the pallet cleaning device  100  in the present embodiment will now be described.  FIG. 19  is a schematic diagram illustrating a pallet work line  60 . The pallet work line  60  includes the pallet cleaning device  100 A with the unstacker  2 A and the pallet cleaning device  100 B with a work line  9  and the stacker  2 B, as illustrated in  FIG. 19 . 
     The pallet cleaning device  100 A can include an ejection line  5  as shown in  FIG. 19 . The ejection line  5  is a line for moving a pallet unstacked from a stack of pallets and placed onto the pallet transfer  25 A and for ejecting the moved pallet from the unstacker  2 A. The ejection line  5  can include a conveyor  5 A that operates by a certain power source. The ejection line  5  can eject a pallet with this conveyor  5 A. 
     The ejection line  5  also has an upper surface wiper  6 A provided so as to abut on the upper surface P 1  of the pallet P ejected from the unstacker  2 A and moved for cleaning the upper surface of the pallet, and a lower surface wiper  6 B provided so as to abut on the lower surface P 5  of the pallet for cleaning the lower surface P 5  of the pallet. The ejection line  5  can further have side surface wipers  6 C provided so as to abut on the side surfaces P 3  of the pallet for cleaning the side surfaces of the pallet. 
     The upper surface wiper  6 A, the lower surface wiper  6 B, and the side surface wipers  6 C may be formed of any material that can clean pallets in the same manner as in the wiping unit  4 A and can be formed, for example, of a mop, cloth, or sponge. Accordingly, dirt, dust, and the like, on the upper surface P 1 , the lower surface P 5 , and the side surfaces P 3  of a pallet can be removed without requiring a special operation mechanism other than the mechanism for moving the pallet in the ejection line. 
     The pallet cleaning device  100 B can include a feed line  7  as shown in  FIG. 19 . The feed line  7  is a line for moving a pallet P to be stacked and feeding the pallet into the stacker  2 B. The feed line  7  can include a conveyor  7 A that operates by a certain power source. The feed line  7  can feed a pallet into the stacker  2 B with this conveyor  7 A. 
     The feed line  7  also has an upper surface wiper  8 A provided so as to abut on the upper surface P 1  of the pallet P moved to be fed into the stacker  2 B for cleaning the upper surface of the pallet, and a lower surface wiper  8 B provided so as to abut on the lower surface P 5  of the pallet for cleaning the lower surface P 5  of the pallet. The feed line  7  can further have side surface wipers  8 C provided so as to abut on the side surfaces P 3  of the pallet for cleaning the side surfaces of the pallet. 
     The upper surface wiper  8 A, the lower surface wiper  8 B, and the side surface wipers  8 C may be formed of any material that can clean pallets in the same manner as in the wiping unit  4 B and can be formed, for example, of a mop, cloth, or sponge. Accordingly, dirt, dust, and the like on the upper surface P 1 , the lower surface P 5 , and the side surfaces P 3  of a pallet can be removed without requiring a special operation mechanism other than the mechanism for moving the pallet in the feed line  7 . 
     The feed line  7  can further have sprays S 3  and S 4  for maintaining the moisture of the surface of pallet P for the purpose of enhancing the cleaning effect, as shown in  FIG. 19 . The sprays S 3  and S 4  spray, for example, water to the surface of pallet P. The sprays S 3  and S 4  may spray not only water but also a liquid detergent, for example, to the pallet. 
     The work line  9  is a line for performing a certain procedure on the pallet output from the pallet cleaning device  100 A and outputting the pallet to the pallet cleaning device  100 B. The procedure performed on the pallet P in the work line  9  includes, for example, checking whether breakage occurs by visual inspection. 
     The wiping unit  4 A in the pallet cleaning device  100 A is formed of, for example, a material capable of absorbing a dust absorber having the ability to chemically absorb dust. upper surface wiper  6 A, the lower surface wiper  6 B, and the side surface wipers  6 C may also be formed of a material capable of absorbing a dust absorber having the ability to chemically absorb dust. Accordingly, the pallet cleaned fully enough to perform a certain procedure can be provided to the work line. 
     The wiping unit  4 B in the pallet cleaning device  100 B is formed of, for example, a water-absorbent material. For example, the wiping unit  4 B can be provided with a mop containing water adequately, so that the pallet P can be fully cleaned in the pallet cleaning device  100 B. The upper surface wiper  8 A, the lower surface wiper  8 B, and the side surface wipers  8 C may also be formed of a water-absorbent material. Accordingly, the pallet can be fully cleaned in the feed line  7 . 
     As described above, the pallet cleaning device  100 B in the present embodiment includes the stacker  2 B for stacking pallets P. In the stacker  2 B, a stack of pallets P are raised in a state the pallets P are put on a pallet P to be stacked. The wiping unit  4 B is provided so as to abut on a side surface of the raised pallets P. Therefore, the pallet side surface is raised in contact with the wiping unit  4 B whereby dirt, dust, and the like on the side surface of the pallet P is removed. This configuration is implemented by simply providing the wiping unit  4 B in the stacker  2 B and does not require a special operation mechanism other than the stacker  2 B. Pallets therefore can be cleaned readily at low cost. 
     The pallet cleaning device  100 A in the present embodiment includes the unstacker  2 A for unstacking a stack of pallets P. In this unstacker  2 A, when the bottom pallet P of a stack of pallets P is unstacked, the stack of pallets P are lowered by the lifter  22 A. The wiping unit  4 A is provided so as to abut on a side surface of the lowered pallet. Therefore, the side surface of the pallet is lowered in contact with the wiping unit  4 A whereby dirt, dust, and the like on the side surface of the pallet is removed. This configuration is implemented by simply providing the wiping unit  4 A in the unstacker  2 A and does not require a special operation mechanism other than the unstacker  2 A. Pallets therefore can be cleaned readily at low cost. 
     Third Embodiment 
     Referring now to  FIG. 20  to  FIG. 21 , an embodiment of a pallet wiping device and a pallet work line as a third embodiment will be described in detail below. 
     A pallet wiping device  1 A in the present embodiment is shown in  FIG. 20 .  FIG. 20  is a perspective view of the pallet wiping device  1 A. 
     As shown in  FIG. 20 , the pallet wiping device  1 A includes a wiping unit  10 A and the pallet cleaning device  100 . 
     Specifically, the pallet wiping device  1 A includes the pallet cleaning device  100  in the second embodiment in place of the pallet placement unit  30  of the pallet wiping device  1  in the first embodiment described with reference to  FIG. 1 . 
     In the third embodiment, the pallet cleaning device  100  is included in the pallet placement unit on which a pallet P is placed such that the direction in which the fork insertion hole P 4  of the pallet P extends is orientated along a certain direction. The wiping unit  10 A can clean the interior of the fork insertion hole P 4  and wipe water left in the interior of the fork insertion hole P 4  of the pallet P placed on the pallet transfer  25  of the pallet cleaning device  100 . The wiping unit  10 A has a cleaning/water-absorbing portion  11 A, an arm  12 , and a cylinder  13  as a power source. The cleaning/water-absorbing portion  11 A cleans the interior of the fork insertion hole P 4  of the pallet P. The cleaning/water-absorbing portion  11 A also wipes water left in the interior of the fork insertion hole P 4 . Specifically, the wiping unit  10 A is aligned with the pallet cleaning device  100  such that the arm  12  reciprocates along the direction in which the fork insertion hole P 4  extends, while the cleaning/water-absorbing portion  11 A is brought into contact with the inner wall surface of the fork insertion hole P 4  of the pallet P placed on the pallet transfer  25  of the stacker/unstacker  2  included in the pallet cleaning device  100 . 
     In the pallet wiping device in the present embodiment, the cleaning/water-absorbing portion  11 A supported by the arm  12  reciprocates along the direction in which the fork insertion hole P 4  extends, while coming into contact with the inner wall surface of the fork insertion hole P 4 , whereby the interior of the fork insertion hole P 4  of the pallet P can be cleaned and water left therein can be removed. In addition, the wiping unit  4  provided in the stacker  2 B or the unstacker  2 A so as to abut on a side surface of the pallet can remove dirt, dust, and the like on the side surface of the raised or lowered pallet. 
       FIG. 21  is a schematic diagram illustrating a pallet work line  60 A in the present embodiment. As shown in  FIG. 21 , the pallet work line  60 A includes a pallet wiping device  1 B ( 1 A) in place of the pallet cleaning device  100 B in the pallet work line  60  in the second embodiment described with reference to  FIG. 19 . The pallet wiping device  1 B includes the pallet cleaning device  100 B configured to include the stacker  2 B and the wiping unit  10 A. 
     The pallet work line  60 A has the pallet cleaning device  100 A at a stage previous to the ejection line  5  in  FIG. 21 , in the same manner as in the second embodiment, but instead may include the pallet wiping device  1  including the pallet cleaning device  100 A configured to include the unstacker  2 A and the wiping unit  10 A. 
     In the pallet work line  60 A in the present embodiment, a work line can be provided at a stage subsequent to the pallet wiping device  1  configured to include the unstacker, so that a certain procedure can be performed on the cleaned pallet. This improves the working efficiency for a certain procedure. Since the pallet wiping device  113  configured to include the stacker is provided at a stage subsequent to the work line, the pallet that has been subjected to a certain procedure can be cleaned and dried. Accordingly, the pallets that have been subjected to a certain procedure can be output to a subsequent stage in a state in which they are cleaned and stacked. 
     INDUSTRIAL APPLICABILITY 
     As described above, the present embodiment provides a pallet wiping device capable of drying the washed pallet reliably at low costs. 
     REFERENCE SIGNS LIST 
       1 ,  1 A,  1 B . . . pallet wiping device,  2  . . . stacker/unstacker,  2 A . . . unstacker,  2 B . . . stacker,  4 ,  4 A,  4 B . . . wiping unit,  5  . . . ejection line,  5 A . . . conveyor,  6 A . . . upper surface wiper,  6 B . lower surface wiper,  6 C . . . side surface wiper,  7  . . . feed line,  7 A . . . conveyor,  8 A . . . upper surface wiper,  8 B . . . lower surface wiper,  8 C . . . side surface wiper,  9  . . . work line,  10 ,  10 A . . . wiping unit,  11  . . . water-absorbing portion,  11  A . . . cleaning/water-absorbing portion,  11   a  . . . ground fabric,  11   b  . . . pile,  12  . . . arm,  12   a  . . . arm coupling member,  13  . . . cylinder,  13   a  . . . tip end,  13   b  . . . rod,  14  . . . rail,  15  . . . base,  16  . . . air blowing device,  21 ,  21 A,  21 B . . . supporter,  22 ,  22 A,  22 B . . . lifter,  23 ,  23 A,  23 B . . . table,  24  . . . frame,  25 ,  25 A,  25 B . . . pallet transfer,  30  . . . pallet placement unit,  50  . . . pallet washing device,  60 ,  60 A . . . pallet work line,  100 ,  100 A,  100 B . . . pallet cleaning device, P, P I , P N , P O , P S  . . . pallet, P 4  . . . fork insertion hole.