Patent Publication Number: US-11396111-B2

Title: Thickness planer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Chinese patent application No. 2019 1063 3943.0 filed on Jul. 15, 2019, the contents of which are fully incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a thickness planer. 
     BACKGROUND ART 
     Japanese Patent No. 4165917 discloses a thickness planer which is driven by power being supplied from an external power source. 
     SUMMARY 
     According to one aspect of the present invention, a thickness planer is provided. The thickness planer has a motor, a planing part that is configured to be driven by the motor and plane a workpiece, a placing part on which the workpiece is placeable, a feeding part that is configured to feed the workpiece placed on the placing part to the planing part. and a battery pack mounting unit to which a battery pack for supplying power to the motor is attachable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a thickness planer. 
         FIG. 2  is a perspective view for showing a feeding area of the thickness planer. 
         FIG. 3  is a front view of the thickness planer. 
         FIG. 4  is a rear perspective view of the thickness planer. 
         FIG. 5  is a rear view of the thickness planer. 
         FIG. 6  is a left side view of the thickness planer with a left side cover removed. 
         FIG. 7  is a right side view of the thickness planer with a right side cover removed. 
         FIG. 8  shows the arrangement position of a battery pack mounting unit. 
         FIG. 9  shows the internal structure of a main housing. 
         FIG. 10  is an explanatory drawing showing a driving mechanism of the thickness planer. 
         FIG. 11  shows the battery pack mounting unit. 
         FIG. 12  shows a battery pack. 
         FIG. 13  is a rear view of the battery pack. 
         FIG. 14  is a partly cutaway left side view of the thickness planer when stored. 
         FIG. 15  is a front view of a thickness planer of a second embodiment. 
         FIG. 16  is a top view of the thickness planer of the second embodiment. 
         FIG. 17  is a front view of a thickness planer of a third embodiment. 
         FIG. 18  is a top view of the thickness planer of the third embodiment. 
         FIG. 19  is a front view of a thickness planer of a fourth embodiment. 
         FIG. 20  is a partly cutaway right side view of the thickness planer of the fourth embodiment. 
         FIG. 21  shows a thickness planer of a fifth embodiment. 
         FIG. 22  is a rear view of the thickness planer of the fifth embodiment. 
         FIG. 23  is a rear view of a thickness planer of a sixth embodiment. 
         FIG. 24  is a top view of the thickness planer of the sixth embodiment. 
         FIG. 25  shows a thickness planer of a seventh embodiment. 
         FIG. 26  is a rear view of the thickness planer of the seventh embodiment. 
         FIG. 27  is a rear view of a thickness planer of an eighth embodiment. 
         FIG. 28  is a front view of a thickness planer of a ninth embodiment. 
         FIG. 29  is a top view of the thickness planer of the ninth embodiment. 
         FIG. 30  shows a thickness planer of a tenth embodiment. 
         FIG. 31  shows a battery pack mounting unit in a first turning state in the thickness planer of the tenth embodiment. 
         FIG. 32  shows the battery pack mounting unit in a second turning state in the thickness planer of the tenth embodiment. 
         FIG. 33  is a front view of a thickness planer of an eleventh embodiment. 
         FIG. 34  is a bottom view of the thickness planer of the eleventh embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     First Embodiment 
     The structure of a thickness planer  1  is briefly described as an embodiment of the present disclosure with reference to  FIGS. 1 to 5 . 
     The thickness planer  1  is configured to feed a workpiece (material to be planed) CM placed on a placing surface  431  of a table  43  to a cutting area (planing area) CA and plane an upper surface of the workpiece CM passing through the cutting area CA. In this embodiment, the thickness planer  1  feeds the workpiece CM placed on the table  43  in a feeding direction shown by an arrow in  FIG. 1 . 
     In the following description, for convenience sake, the feeding direction is defined as a front-rear direction, and in the front-rear direction, the side of the thickness planer  1  to which the workpiece CM is fed is defined as a rear side and the opposite side is defined as a front side. Specifically, the workpiece CM is fed from the front side to the rear side of the thickness planer  1 . Further, a direction perpendicular to the placing surface  431  of the table  43  on which the workpiece CM is placed is defined as a vertical direction. In the vertical direction, a direction from the table  43  toward the workpiece CM is defined as an upper direction and the opposite direction is defined as a lower direction. Further, a direction perpendicular to the front-rear direction and the vertical direction is defined as a left-right direction. In the left-right direction, a left and right sides in the feeding direction are respectively defined as a left side and a right side. 
     As shown in the drawings, the thickness planer  1  has a body unit  10  having a cutting (planing) function. A top cover  41  is arranged above the body unit  10  and a base  80  is arranged below the body unit  10 . The table  43  is arranged on an upper side of the base  80 . Further, a left side cover  46  and a right side cover  47  are arranged on left and right sides of the body unit  10 , respectively. 
     A lifting handle  48  is provided on the top cover  41  and configured to be rotatable around a rotation axis extending in the vertical direction. The body unit  10  is configured to be raised and lowered in the vertical direction with respect to the table  43  by user&#39;s operation of turning the lifting handle  48 . The vertical length of the cutting area CA which is surrounded by the body unit  10 , the table  43 , the left side cover  46  and the right side cover  47  can be adjusted by raising and lowering the body unit  10 . The thickness planer  1  is configured to be capable of planing the workpiece CM of different thicknesses by adjusting the vertical length of the cutting area CA according to the thickness (vertical length) of the workpiece CM. 
     A front auxiliary table  44  is pivotally supported around a pivot axis extending in the left-right direction on a front end of the table  43 . Further, a rear auxiliary table  45  is pivotally supported around a pivot axis extending in the left-right direction on a rear end of the table  43 . The front auxiliary table  44  and the rear auxiliary table  45  have respectively a placing surface  441  and a placing surface  451  on which the workpiece CM can be placed. The placing surfaces  441 ,  431 ,  451  are configured to be flush with each other when the front and rear auxiliary tables  44 ,  45  are placed in a horizontal state (unfolded or open state). When turned upward around the pivot axis, the front and rear auxiliary tables  44 ,  45  are folded (closed) upward from the front and rear ends of the table  43 . 
     As described above, an area which is surrounded by the body unit  10 , the table  43 , the left side cover  46  and the right side cover  47  is defined as the cutting area (planing area) CA. Further, as shown in  FIG. 2 , an area through which the workpiece CM passes while being fed is defined as a feeding area TA. Furthermore, as shown in  FIG. 3 , an area above the top cover  41  including the lifting handle  48  is defined as a cover upper area CUA. An area above an upper end of a main housing  100  is defined as a housing upper area HUA. An area extending from a lower end of a main frame  30  of the body unit  10  to the upper end of the main housing  100  is defined as a driving mechanism arrangement area DMA. An area below the placing surface  431  of the table  43  is defined as a base area BSA. An area extending on the left side of the left side cover  46  is defined as a left side area LSA. An area extending on the right side of the right side cover  47  is defined as a right side area RSA. 
     In this embodiment, a battery pack mounting unit  50  is mounted in an area above the main housing  100  and below the top cover  41 . In other words, the battery pack mounting unit  50  is mounted in the housing upper area HUA. Specifically, the battery pack mounting unit  50  is fastened to a lower surface of the top cover  41  by a plurality of screw parts. The battery pack mounting unit  50  is configured to be mounted such that two battery packs  60  is removably attached thereto. The battery packs  60  are attached and detached by being slid with respect to the battery pack mounting unit  50 . 
     As shown in  FIGS. 4 and 5 , the battery packs  60  are attached and detached by being slid in the front-rear direction with respect to the battery pack mounting unit  50  from the rear of the thickness planer  1 . An arch-shaped escape part  420  is formed in a rear part of the top cover  41  and facilitates user&#39;s operation of attaching and detaching the battery pack  60 . 
     The battery pack mounting unit  50  and the body unit  10  are electrically connected to each other by an electric cord  52 . The thickness planer  1  in this embodiment has the rated voltage of 36 volts. The battery packs  60  each having a nominal voltage of 18 volts are electrically connected in series and attached to the battery pack mounting unit  50 . The thickness planer  1  is driven by power supply from the battery packs  60  attached to the battery pack mounting unit  50 . The battery pack mounting unit  50  and the battery pack  60  will be described below in detail. 
     As shown in  FIG. 3 , the body unit  10  includes the main housing  100  and the main frame  30 . On the main housing  100 , a residual capacity display part  19  is provided to display a battery residual capacity of each of the battery packs  60  attached to the battery pack mounting unit  50 . The residual capacity display part  19  is provided with two residual capacity gauges  191  and  192 . The residual capacity gauges  191  and  192  respectively display battery residual capacities of the two battery packs  60  attached to the battery pack mounting unit  50 . The residual capacity gauge  191  has three LED lamps arranged in a row in the left-right direction. When the battery pack  60  associated with the residual capacity gauge  191  is fully charged, all of the three LED lamps illuminate. The three LED lamps are sequentially turned off as the battery residual capacity of the battery pack  60  decreases. The structure of the residual capacity gauge  192  has the same structure as the residual capacity gauge  191  and is not therefore described here. 
     Further, a main switch  71  and a lever switch  72  are provided on the main housing  100 . When the main switch  71  is turned on, power is supplied up to the lever switch  72  in an electrical circuit from the battery packs  60  attached to the battery pack mounting unit  50  to a motor  15  described below. When the lever switch  72  is turned on while the main switch  71  is kept on, power is supplied to the motor  15  and the motor  15  starts rotating. Thus, the thickness planer  1  comes into a driven state ready for planing the workpiece CM. 
     The main switch  71  is a push-button alternate switch. Once pressed in the off state, the main switch  71  is turned on and kept in the on state, while once pressed in the on state, the main switch  71  is turned off and kept in the off state. 
     The lever switch  72  is pivotally supported around a pivot axis extending in the left-right direction by the main housing  100 . When the lever switch  72  in the off state is turned upward by a prescribed angle around the pivot axis, the lever switch  72  is turned on and kept in the on state, while, when the lever switch  72  in the on state is turned downward around the pivot axis and returned to an initial position, the lever switch  72  is turned off and kept in the off state. In the thickness planer  1  shown in  FIGS. 1 to 5 , the lever switch  72  is in the off state. In the thickness planer  1  of this embodiment, the main switch  71  and the lever switch  72  are arranged adjacent to each other so as to provide ease of operation for a user. 
     When the workpiece CM is fed to the cutting area CA while the main switch  71  and the lever switch  72  are in the on state and the thickness planer  1  is driven, the thickness planer  1  planes the workpiece CM. Shavings generated when the thickness planer  1  planes the workpiece CM are discharged from a chip discharge port  145  provided in a rear part of the body unit  10 . An air is jetted from the chip discharge port  145  and blows off the shavings discharged from the chip discharge port  145 , thereby preventing the shavings from being accumulated in the vicinity of the chip discharge port  145 . Further, a plate-like chip cover  350  is fastened to the main frame  30  above the chip discharge port  145  by screw parts  351 ,  352 . The chip cover  350  prevents the scattering of the shavings discharged from the chip discharge port  145 . 
     The detailed structure of the thickness planer  1  is now described with reference to  FIGS. 6 to 10 . 
     As shown in  FIGS. 6 to 8 , columns  411 ,  412 ,  413 ,  414  are erected vertically to the placing surface  431  in four corners of the base  80 . Upper ends of the columns  411 ,  412 ,  413 ,  414  are fastened to the top cover  41  by screw parts  415 ,  416 ,  417 ,  418 , respectively. Further, sliding parts  341 ,  342 ,  343 ,  344  are respectively provided on four corners of the main frame  30  and slidable in the vertical direction with respect to the columns  411 ,  412 ,  413 ,  414 . The sliding parts  341 ,  342 ,  343 ,  344  have respective through holes through which the columns  411 ,  412 ,  413 ,  414  are respectively slidably inserted. 
     On left and right end parts of the base  80 , lifting screw shafts  485 ,  486  are erected vertically to the placing surface  431  so as to be rotatable via respective bearing members provided on the placing surface  431 . Lower end parts of the lifting screw shafts  485 ,  486  both protrude downward from the base  80 . A space (lower side area) is formed on the lower side of the base  80 . The lifting shaft (not shown) which is a rotation axis extending in the left-right direction is arranged in the lower side area of the base  80 . The lifting shaft connects the lower end parts of the lifting screw shafts  485 ,  486 . The lifting shaft is provided to synchronize rotation of the lifting screw shaft  485  and rotation of the lifting screw shaft  486 . The lifting shaft converts rotation of the lifting screw shaft  485  around a rotation axis extending in the vertical direction into rotation around a rotation axis extending in the left-right direction and further converts this rotation into rotation around a rotation axis extending in the vertical direction, thereby rotating the lifting screw shaft  486 . 
     Lifting screw hole parts  345 ,  346  are provided in left and right end parts of the main frame  30 . The lifting screw hole parts  345 ,  346  have respective through holes extending therethrough in the vertical direction and the lifting screw shafts  485 ,  486  are rotatably threadedly engaged with the through holes, respectively. As shown in  FIG. 8 , an upper end part of the lifting screw shaft  485  extends through the top cover  41  and is connected to the lifting handle  48 . When the lifting handle  48  is turned by a user, the lifting screw shaft  485  rotates together with the lifting handle  48 . Further, the lifting screw shaft  486  rotates in synchronization with the rotation of the lifting screw shaft  485 . When the lifting screw shafts  485 ,  486  are rotated, the lifting screw hole parts  345 ,  346  receive force in an upward or downward direction from the lifting screw shafts  485 ,  486  and thus the main frame  30  slides upward or downward. By upward or downward slide of the main frame  30 , the body unit  10  slides upward or downward, so that the length of the cutting area CA in the vertical direction is changed. In this manner, the length of the cutting area CA in the vertical direction is changed by user&#39;s operation of rotating the lifting handle  48 . 
     Next, the body unit  10  is described in detail. 
     As shown in  FIG. 9 , the main housing  10  has a first housing  110 , a second housing  160  and a third housing  180 . The motor  15  and a controller  112  are housed in the first housing  110 . The controller  112  has a control board  114  for controlling driving of the motor  15 . The control board  114  has a transistor  115  for switching the current flowing to the motor  15 . In this embodiment, an FET (Field Effect Transistor) is adopted as the transistor  115 . The control board  114  controls driving of the motor  15  by PWM (Pulse Width Modulation) control using the transistor  115 . 
     The motor  15  is disposed below the controller  112 . In this embodiment, a brushless motor having a stator  151 , a rotor  152  and a motor shaft  153  extending from the rotor  152  is adopted as the motor  15 . The motor shaft  153  extending in the left-right direction is rotatably supported at its left and right end parts by bearings  154 ,  155 . In this embodiment, when the motor  15  and the bearing  155  are assembled into the first housing  110 , the motor shaft  153  is inserted into the first housing  110  from the outside of a right end wall part  118  of the first housing  110 . After the motor shaft  153  is inserted into the first housing  110 , the bearing  155  is mounted to the first housing  110  from the outside of the right end wall part  118  so as to journal the motor shaft  153 . 
     A fan  156  is provided onto the motor shaft  153  between the bearing  154  and the rotor  152 . The fan  156  rotates together with the motor shaft  153  around a rotation axis of the motor shaft  153 . The main housing  100  has an intake port  121  and an outlet port  125 . Further, an air flow passage is formed in the main housing  100  to provide communication between the intake port  121  and the outlet port  125 . The fan  156  generates flow of air from the intake port  121  to the outlet port  125  through the air flow passage. The air flowing through the air flow passage cools the motor  15  and the controller  112 . 
     Gears  161 ,  162 ,  163  are housed in the second housing  160 . Each of the three gears  161 ,  162 ,  163  is configured to be rotatable around a rotation axis parallel to the rotation axis of the motor shaft  153 . A left end part of the motor shaft  153  protrudes into the second housing  160  and the gear  161  is engaged with this protruding part. The gear  161  engages with the gear  162  and the gear  162  engages with the gear  163 . A drive shaft  164  is housed in the third housing  180  and a right end part of the drive shaft  164  is integrally connected to the gear  163 . The drive shaft  164  is configured to be rotatable around a rotation axis parallel to the rotation axis of the motor shaft  153 . The drive shaft  164  rotates together with the gear  163 . Rotational power (speed) of the motor  15  is appropriately changed via the gears  161 ,  162 ,  163  and then transmitted to the drive shaft  164 . As shown in  FIG. 10 , a gear  166  is connected to a left end part of the drive shaft  164  and rotates together with the drive shaft  164 . A chain  301  is looped over the gear  166 . Feed rollers  31 ,  33  are housed in the main frame  30 . The chain  301  is looped over a gear  312  of the feed roller  31  and a gear  332  of the feed roller  33 . Rotational power of the drive shaft  164  is transmitted to the feed roller  31  via the gear  166 , the chain  301  and the gear  312  and also transmitted to the feed roller  33  via the gear  166 , the chain  301  and the gear  332 . 
     As shown in  FIG. 10 , a cutter head  21  for planing the workpiece CM and the feed rollers  31 ,  33  for feeding the workpiece CM are disposed in the main frame  30 . The feed roller  31  is disposed in front of the cutter head  21  and the feed roller  33  is disposed behind the cutter head  21 . The feed roller  31  has a shaft  311 , a gear  312  and a roller part  313 . The shaft  311  is configured to be rotatable around a rotation axis extending in the left-right direction. The gear  312  is integrally connected to a left end part of the shaft  311 . The roller part  313  is provided peripherally around the rotation axis of the shaft  311  and comes into contact with the workpiece CM when feeding the workpiece CM. The feed roller  33  has a shaft  331 , a gear  332  and a roller part  333 . The shaft  331  is configured to be rotatable around a rotation axis extending in the left-right direction. The roller part  333  is provided peripherally around the rotation axis of the shaft  331  and comes into contact with the workpiece CM when feeding the workpiece CM. The roller parts  313 ,  333  are configured to transmit rotating forces of the feed rollers  31 ,  33  as driving force to the workpiece CM. 
     As shown in  FIG. 10 , a pulley  157  is connected to a right end part of the motor shaft  153  so as to rotate together with the motor shaft  153 . A belt  201  is looped over the pulley  157 . The belt  201  is looped over a pulley  211  of the cutter head  21 . The rotating power (speed) of the motor  15  is appropriately changed via the pulley  157 , the belt  201  and the pulley  211  and is transmitted to the cutter head  21 . 
     The cutter head  21  is configured to be rotatable around a rotation axis extending in the left-right direction. Plane blades  213 ,  214  are provided extending in parallel to the rotation axis on a periphery of the cutter head  21 . The plane blades  213 ,  214  are fastened to the cutter head  21  by a plurality of screw parts  215  in symmetrical positions with respect to the rotation axis of the cutter head  21 . A pulley  211  is connected to a right end part of the cutter head  21  so as to rotate together with the cutter head  21 . As described above, the cutter head  21  is rotated by the rotational power of the motor  15  which is transmitted via the pulley  157 , the belt  201  and the pulley  211 . The plane blades  213 ,  214  of the cutter head  21  plane the workpiece CM which is fed rearward from the front by the feed rollers  31 ,  33 . 
     Next, the battery pack mounting unit  50  and the battery pack  60  are described with reference to  FIGS. 8 and 11 to 14 . 
     Each of the battery packs  60  has a nominal voltage of 18 volts and is used as a power source for the thickness planer  1 . The battery pack  60  can also be used as a power source for power tools other than the thickness planer  1 , including an electric drill, an electric driver, an electric wrench, an electric grinder, an electric circular saw, an electric reciprocating saw, an electric jigsaw, an electric hammer, an electric cutter, an electric chainsaw, an electric planer, an electric nailing machine, an electric hedge trimmer, an electric lawn clipper, an electric lawnmower, an electric bush cutter, an electric blower and an electric cleaner. 
     The battery pack  60  can be referred to as a battery package or an assembled battery. The battery pack  60  has an outer housing formed into a prescribed size and five lithium-ion battery cells which are housed within the outer housing and connected in series. The battery pack  60  is rechargeable and can be recharged with a charger (not shown) after used as a power source for the thickness planer  1  or other power tools. The battery pack  60  is a so-called slide-type battery pack and can be removably attached to the battery pack mounting unit  50  of the thickness planer  1  and the charger. 
     As shown in  FIG. 12 , a pair of left and right rail receiving parts  61   a  are provided in the battery pack  60 . In the following description, the side of the battery pack  60  on which the rail receiving parts  61   a  are disposed is defined as an upper side of the battery pack  60  and the side opposite to the upper side of the battery pack  60  is defined as a lower side of the battery pack  60 . A positive output terminal  61   b  and a negative output terminal  61   c  are arranged between the left and right rail receiving parts  61   a . Between the positive output terminal  61   b  and the negative output terminal  61   c , a connector part  61  is arranged to transmit/receive a control signal to/from the charger when the battery pack  60  is charged by the charger. Further, a lock member  61   e  is provided on an upper part of the battery pack  60  and a spring member (not shown) is arranged below the lock member  61   e  within the housing of the battery pack  60 . This spring member biases the lock member  61   e  upward. An unlock button  61   f  is arranged on a back side of the battery pack  60  and the lock member  61   e  moves downward when the unlock button  61   f  (see  FIG. 13 ) is pressed down. 
     As shown in  FIG. 11 , the battery pack mounting unit  50  has two mounting parts  51  having the same structure. The mounting parts  51  is electrically connected in series. Therefore, in the battery pack mounting unit  50 , the battery packs  60  each having a nominal voltage of 18 volts can be connected in series. As described above, the thickness planer  1  has the rated voltage of 36 volts, and the thickness planer  1  can be driven by power supply from the battery pack mounting unit  50  to which the two battery packs  60  are attached. A pair of left and right rail parts  51   a  are provided in each of the mounting parts  51 . A positive input terminal  51   b  and a negative input terminal  51   c  are arranged between the rail parts  51   a . Further, a lock receiving hole  51   e  is provided in the mounting part  51  to be engaged with the lock member  61   e  of the battery pack  60 . 
     In order to attach the battery pack  60  to the mounting part  51 , the battery pack  60  is slid in a mounting direction with respect to the mounting part  51  such that the rail receiving part  61   a  is engaged with the rail part  51   a . Further, in the following description, a direction along the rail part  51   a  of the battery pack mounting unit  50  is defined as a sliding direction. When the battery pack  60  is attached to the mounting part  51 , the positive input terminal  51   b  and the negative input terminal  51   c  of the mounting part  51  are electrically connected to the positive output terminal  61   b  and the negative output terminal  61   c  of the battery pack  60 , respectively. Further, when the battery pack  60  is attached to the mounting part  51 , the lock member  61   e  is engaged with the lock receiving hole  51   e , so that the battery pack  60  is fixed and locked so as to be unmovable in the sliding direction. 
     When the unlock button  61   f  of the battery pack  60  mounted to the mounting part  51  is pressed down by a user, the battery pack  60  is disengaged from the lock receiving hole  51   e  (the battery pack  60  is unlocked). In the unlocked state, the battery pack  60  is removed from the mounting part  51  by being slid in a removing direction with respect to the mounting part  51 . In this manner, the battery pack  60  can be removably attached to the mounting part  51  of the battery pack mounting unit  50 . 
     A mounting position of the battery pack mounting unit  50  in the thickness planer  1  of this embodiment is described in detail with reference to  FIGS. 8 and 14 . 
     The battery pack mounting unit  50  is arranged in the thickness planer  1  such that the battery pack mounting unit  50  and the battery pack  60  lie in a position avoiding the feeding area TA (see  FIG. 2 ). In this embodiment, the battery pack mounting unit  50  and the battery pack  60  are arranged in the housing upper area HUA (see  FIG. 3 ). Specifically, the battery pack mounting unit  50  is arranged above the main housing  100  and below the top cover  41 . As shown in  FIG. 14 , in the thickness planer  1  of this embodiment, a length HL of the main housing  100  in the front-rear direction is shorter than a length FL of the main frame  30  in the front-rear direction and the main housing  100  is arranged in a front part of an area above the main frame  30 . Thus, a free space exists in a rear part of the area above the main frame  30 . Therefore, in this embodiment, the battery pack mounting unit  50  is fixed to a rear part of a lower surface of the top cover  41  by a plurality of screw parts. By provision of such a structure, when the body unit  10  is raised up to a highest position with respect to the table  43 , the battery pack  60  and the battery pack mounting unit  50  are fitted in this free space and thus avoided from getting into contact with the body unit  10 . 
     In this embodiment, the battery pack mounting unit  50  is mounted to the top cover  41  with the mounting part  51 , the rail parts  51   a , the positive input terminal  51   b  and the negative input terminal  51   c  facing downward. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50  with the rail receiving part  61   a , the positive output terminal  61   b  and the negative output terminal  61   c  facing upward. 
     As described above, the battery pack mounting unit  50  and the main housing  100  are connected to each other by an electric cord  52 . In this embodiment, the electric cord  52  is extended from the battery pack mounting unit  50  in a direction twisted with respect to the direction in which the electric cord  52  is extended from the main housing  100 . Specifically, as shown in  FIG. 8 , the electric cord  52  is extended from the battery pack mounting unit  50  in the left-right direction, while the electric cord  52  is extended from the main housing  100  in the front-rear direction. In other words, when viewed from above, the direction in which the electric cord  52  is extended from the battery pack mounting unit  50  is substantially perpendicular to the direction in which the electric cord  52  is extended from the main housing  100 . By provision of such a structure, when the distance between the main housing  100  and the battery pack mounting unit  50  is shortened as the body unit  10  is raised with respect to the table  43 , the surplus length of the electric cord  52  with respect to the distance between the main housing  100  and the battery pack mounting unit  50  escapes into a free space existing behind the main housing  100  and on the left side of the battery pack mounting unit  50  while being gently curved or bent. Thus, when the body unit  10  is raised, the electric cord  52  is avoided from being sharply curved or bent. 
     As shown in  FIG. 14 , when the thickness planer  1  is transported or stored, the front auxiliary table  44  and the rear auxiliary table  45  are turned upward around a pivot axis extending in the left-right direction so as to be folded upward from the front and rear ends of the table  43  (closed). The thickness planer  1  of this embodiment is configured such that rear end parts of the battery pack mounting unit  50  and the battery pack  60  are located forward (inward) of a rear end of the closed rear auxiliary table  45 . Therefore, the battery pack mounting unit  50  and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 . 
     The lifting handle  48  is provided on an upper surface of the top cover  41  and supported by a pivot shaft  483 . When the thickness planer  1  is used, as shown in  FIG. 4 , the lifting handle  48  is turned around the pivot shaft  483  such that an operation part  481  of the lifting handle  48  faces upward. On the other hand, when the thickness planer  1  is transported or stored, as shown in  FIG. 14 , the lifting handle  48  is turned around the pivot shaft  483  and folded such that the operation part  481  of the lifting handle  48  faces downward. When the lifting handle  48  is folded, an upper end of the lifting handle  48  is located below an upper end of the top cover  41 . By provision of such a structure, the lifting handle  48  is avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 . 
     As described above, the thickness planer  1  of this embodiment has the battery pack mounting unit  50  for mounting the battery pack  60 . Thus, with the battery pack  60  being attached to the battery pack mounting unit  50 , power can be supplied to the motor  15  to drive the thickness planer  1 . Therefore, the thickness planer  1  can be driven without an external power source, so that the convenience of the thickness planer  1  is enhanced. 
     In this embodiment, the battery pack mounting unit  50  is configured such that the battery pack mounting unit  50  and the battery pack  60  attached to the battery pack mounting unit  50  lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50  and the battery pack  60  are arranged in the housing upper area HUA. Particularly, in this embodiment, the battery pack mounting unit  50  is arranged above the main housing  100 . Therefore, during planing operation by a user, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50  and the battery pack  60  while being fed, so that decrease in working efficiency is avoided. Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50  and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50  and the battery pack  60  in the thickness planer  1 . 
     The battery pack mounting unit  50  and the battery pack  60  are surrounded on the upper and lower sides and the left and right sides by other members. Specifically, the top cover  41 , the main housing  100  and the left and right side covers  46 ,  47  are arranged above and below and on the left and right sides of the battery pack mounting unit  50  and the battery pack  60 , respectively. Therefore, the battery pack mounting unit  50  and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during planing operation and transportation. 
     In this embodiment, the battery pack mounting unit  50  is arranged below the top cover  41 . Therefore, the size of a portion of the thickness planer  1  above the top cover  41  (the length of the thickness planer  1  in the vertical direction) is avoided from increasing due to arrangement of the battery pack mounting unit  50 . As a result, the thickness planer  1  realizes space saving when stored. 
     In this embodiment, the battery pack mounting unit  50  is mounted to the lower surface of the top cover  41 , so that the battery pack mounting unit  50  and the battery pack  60  are adequately protected from impact and contact from above the top cover  41 . 
     The thickness planer  1  of this embodiment is configured such that the rear end parts of the battery pack mounting unit  50  and the battery pack  60  are located forward (inward) of the rear end of the closed rear auxiliary table  45 . Therefore, the battery pack mounting unit  50  and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 . Thus, according to this embodiment, the storability and portability of the thickness planer  1  are improved. 
     In the thickness planer  1  of this embodiment, the lifting handle  48  is configured to be turned around the pivot shaft  483  and folded such that the operation part  481  of the lifting handle  48  faces downward. When the lifting handle  48  is folded, the upper end of the lifting handle  48  is located below the upper end of the top cover  41 . By provision of such a structure, the lifting handle  48  is avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 . Therefore, the thickness planer  1  is provided with improved storability and portability. 
     The battery pack mounting unit  50  is configured such that the battery pack  60  is removably attached thereto. Therefore, when the residual capacity of the battery pack  60  which supplies power to the thickness planer  1  is reduced, this battery pack  60  can be easily replaced with a fully charged battery pack  60 . Further, the battery pack  60  is attached with its upper surface facing upward. Therefore, a user can attach and detach the battery pack  60  while supporting the weight of the battery pack  60  by a hand. Particularly, when detaching the battery pack  60 , the user can hold the battery pack  60  detached from the battery pack mounting unit  50  on a palm of the user, so that the user does not have to handle the battery pack  60  with too much care. 
     In this embodiment, the battery pack mounting unit  50  is configured such that the two battery packs  60  can be attached thereto and the battery packs  60  attached to the battery pack mounting unit  50  are electrically connected to the motor  15  in series. Specifically, the two battery packs  60  each having a nominal voltage (18 volts) lower than the rated voltage (36 volts) of the thickness planer  1  are attached to the battery pack mounting unit  50  to drive the thickness planer  1 . Therefore, the battery packs  60  having a nominal voltage lower than the rated voltage of the thickness planer  1  are effectively used. 
     The battery pack  60  can also be used as a power source for other power tools. Therefore, when other power tools are used, a new battery pack need not be prepared and the battery pack  60  to be used for the thickness planer  1  can be further effectively used. 
     In this embodiment, the main switch  71  and the lever switch  72  are arranged on the front side of the thickness planer  1 . During planing operation, the workpiece CM is fed to the cutting area CA from the front of the thickness planer  1 . Therefore, a user normally starts an operation in front of the thickness planer  1 . In this case, when a user starts the operation, the main switch  71  and the lever switch  72  are located in front of the user. Therefore, according to this embodiment, operability of the thickness planer  1  is improved. 
     Particularly, in this embodiment, the main switch  71  and the lever switch  72  are arranged adjacent to each other on the front side of the thickness planer  1 , so that the operability of the thickness planer  1  is further improved. 
     Further, in this embodiment, the residual capacity display part  19  is arranged on the front side of the thickness planer  1 , so that a user can perform a planing operation while checking the residual capacity of the battery pack  60 . Therefore, convenience of the thickness planer  1  is improved. 
     In this embodiment, the electric cord  52  is extended from the battery pack mounting unit  50  in a direction twisted with respect to the direction in which the electric cord  52  is extended from the main housing  100 . Further, in this embodiment, when viewed from above, the direction in which the electric cord  52  is extended from the battery pack mounting unit  50  is substantially perpendicular to the direction in which the electric cord  52  is extended from the main housing  100 . Therefore, when the body unit  10  is raised, the electric cord  52  escapes into a free space existing behind the main housing  100  and on the left side of the battery pack mounting unit  50  while being gently curved or bent, thereby being avoided from being sharply curved or bent. Thus, deterioration of the electric cord  52  is suppressed, so that durability of the thickness planer  1  is improved. 
     Second Embodiment 
     A thickness planer  1 A according to a second embodiment of the present disclosure is now described with reference to  FIGS. 15 and 16 . A main difference between the thickness planer  1 A of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 A and the battery pack  60  are arranged. 
     The thickness planer  1 A of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 A is arranged on top of the main housing  100 . Specifically, the battery pack mounting unit  50 A is arranged in the housing upper area HUA. Particularly, in this embodiment, the battery pack mounting unit  50 A is fastened to the top of the main housing  100  by a plurality of screw parts. In an upper front part of a top cover  41 A arranged on the upper side of the thickness planer  1 A, an escape part  420 A is formed to be open at an upper front end of the top cover  41 A. Specifically, the escape part  420 A is formed into a recessed shape such that the whole top surface of the battery pack  60  attached to the battery pack mounting unit  50 A is visible when viewed from above. Further, the escape part  420 A is formed into such a shape that the whole front surface of the battery pack  60  attached to the battery pack mounting unit  50 A is visible when viewed from the front. 
     The battery pack mounting unit  50 A is mounted onto the top of the main housing  100  in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 A. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 A by being slid rearward with respect to the battery pack mounting unit  50 A from the front of the thickness planer  1 A. Thus, the mounting direction is a direction heading from the front to the rear of the thickness planer  1 A. Further, the battery pack  60  is detached from the battery pack mounting unit  50 A by being slid forward with respect to the battery pack mounting unit  50 A in the thickness planer  1 A. Thus, the removing direction is a direction heading from the rear to the front of the thickness planer  1 A. 
     In such a structure, the unlock button  61   f  of the battery pack  60  can be operated from the front of the thickness planer  1 A. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 A like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. 
     The thickness planer  1 A of this embodiment is configured such that rear end parts of the battery pack mounting unit  50 A and the battery pack  60  are located rearward (inward) of a front end of the closed front auxiliary table  44 . Therefore, the battery pack mounting unit  50 A and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 A. Thus, the thickness planer  1 A is provided with improved storability and portability. 
     As described above, the thickness planer  1 A of this embodiment has the escape part  420 A in the upper front part of the top cover  41 A, which facilitates attachment and detachment of the battery pack  60 . 
     Further, the battery pack mounting unit  50 A is mounted onto the top of the main housing  100  in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 A. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 A like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA, so that convenience of the thickness planer  1 A is improved. 
     Further, in the thickness planer  1 A of this embodiment, the battery pack mounting unit  50 A is fastened to the top of the main housing  100  by the screw parts. Therefore, the battery pack mounting unit  50 A and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 A. 
     In this embodiment, like in the first embodiment, the battery pack mounting unit  50 A is configured such that the battery pack mounting unit  50 A and the battery pack  60  attached to the battery pack mounting unit  50 A lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 A is arranged in the housing upper area HUA. Particularly, in this embodiment, like in the first embodiment, the battery pack mounting unit  50 A is arranged above the main housing  100 . Therefore, during planing operation by a user, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 A and the battery pack  60  while being fed. Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 A and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 A and the battery pack  60  in the thickness planer  1 A. 
     In this embodiment, the battery pack mounting unit  50 A is arranged below the top cover  41 A. Therefore, the size of a portion of the thickness planer  1 A above the top cover  41 A (the length of the thickness planer  1 A in the vertical direction) is avoided from increasing due to arrangement of the battery pack mounting unit  50 A. As a result, the thickness planer  1 A realizes space saving when stored or loaded. 
     In this embodiment, the battery pack mounting unit  50 A is mounted to the top of the main housing  100 , so that a free space above the main housing  100  is effectively utilized. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     Further, it may be configured such that the battery pack mounting unit  50 A is fixed to the main housing  100  in a different orientation from that in this embodiment. For example, the battery pack mounting unit  50 A may be fixed to the main housing  100  in such an orientation that the battery pack  60  is mounted thereto from the rear or the left or right side of the thickness planer  1 A. 
     The direction in which the escape part  420 A opens in the top cover  41 A may be changed according to the orientation of the battery pack mounting unit  50 A mounted to the main housing  100 . For example, when the battery pack mounting unit  50 A is fixed to the main housing  100  in such an orientation that the battery pack  60  is mounted thereto from the rear of the thickness planer  1 A, the escape part  420 A may be formed to be open at an upper rear end of the top cover  41 A. When the battery pack mounting unit  50 A is fixed to the main housing  100  in such an orientation that the battery pack  60  is mounted thereto from the left or right side of the thickness planer  1 A, the escape part  420 A may be formed to be open at an upper left or right end of the top cover  41 A. 
     The escape part  420 A formed in the top cover  41 A may be shaped as follows. The escape part may be formed into a recessed shape such that part of the top surface of the battery pack  60  attached to the battery pack mounting unit  50 A is visible when viewed from above. Further, the escape part  420 A may be formed into such a shape that part of the front surface of the battery pack  60  attached to the battery pack mounting unit  50 A is visible when viewed from the front. 
     In this embodiment, the main housing  100  and the battery pack mounting unit  50 A may be integrally formed with each other. In this case, the strengths of the main housing  100  and the battery pack mounting unit  50 A are improved. 
     The structure in which the battery pack mounting unit  50 A and the battery pack  60  are arranged on the top of the main housing  100  may be applied to a thickness planer not having the top cover on the top of the main housing. By provision of such a structure, like in this embodiment, a free space above the main housing  100  is effectively utilized. 
     Third Embodiment 
     A thickness planer  1 B according to a third embodiment of the present disclosure is now described with reference to  FIGS. 17 and 18 . A main difference between the thickness planer  1 B of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 B and the battery pack  60  are arranged. 
     The thickness planer  1 B of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, a battery pack housing part  410 B is provided on a top cover  41 B and houses at least parts of the battery pack mounting unit  50 B and the battery pack  60  attached to the battery pack mounting unit  50 B. The battery pack housing part  410 B is arranged above the main housing  100 . 
     The battery pack housing part  410 B is configured to house at least parts of the battery pack mounting unit  50 B and the battery pack  60  attached to the battery pack mounting unit  50 B below an upper surface of the top cover  41 B. More specifically, the battery pack mounting unit  50 B is arranged in the housing upper area HUA and the cover upper area CUA. 
     The battery pack housing part  410 B is formed to be open at an upper front end of the top cover  41 B. Specifically, the battery pack housing part  410 B is formed into a recessed shape such that the whole top surface of the battery pack  60  attached to the battery pack mounting unit  50 B is visible when viewed from above. Further, the battery pack housing part  410 B is formed into a recessed shape such that the whole front surface of the battery pack  60  attached to the battery pack mounting unit  50 B is visible when viewed from the front. 
     The battery pack mounting unit  50 B is fastened to a bottom of the battery pack housing part  410 B by a plurality of screw parts. The battery pack mounting unit  50 B is mounted to the bottom of the battery pack housing part  410 B in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 B. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 B by being slid rearward with respect to the battery pack mounting unit  50 B from the front of the thickness planer  1 B. Thus, the mounting direction is a direction heading from the front to the rear of the thickness planer  1 B. Further, the battery pack  60  is detached from the battery pack mounting unit  50 B by being slid forward with respect to the battery pack mounting unit  50 B in the thickness planer  1 B. Thus, the removing direction is a direction heading from the rear to the front of the thickness planer  1 B. 
     In such a structure, the unlock button  61   f  of the battery pack  60  can be operated from the front of the thickness planer  1 B. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 B like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. 
     The thickness planer  1 B of this embodiment is configured such that rear end parts of the battery pack mounting unit  50 B and the battery pack  60  are located rearward (inward) of the front end of the closed front auxiliary table  44 . Therefore, the battery pack mounting unit  50 B and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 B. Thus, the thickness planer  1 B is provided with improved storability and portability. 
     As described above, in the thickness planer  1 B according to this embodiment, the battery pack housing part  410 B is provided on the top cover  41 B and houses at least parts of the battery pack mounting unit  50 B and the battery pack  60  attached to the battery pack mounting unit  50 B. Therefore, at least parts of the battery pack mounting unit  50 B and the battery pack  60  attached to the battery pack mounting unit  50 B are protected. For example, the battery pack mounting unit  50 B and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment. 
     Further, the battery pack housing part  410 B is formed to be open at the upper front end of the top cover  41 B, which facilitates attachment and detachment of the battery pack  60 . 
     Further, the battery pack mounting unit  50 B is mounted to the bottom of the battery pack housing part  410 B in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 B. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 B like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA, so that convenience of the thickness planer  1 B is improved. 
     In the thickness planer  1 B according to this embodiment, the battery pack mounting unit  50 B is fastened to the bottom of the battery pack housing part  410 B by a plurality of the screw parts. Therefore, the battery pack mounting unit  50 B and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 B. 
     In the thickness planer  1 B according to this embodiment, like in the first embodiment, the battery pack mounting unit  50 B is configured such that the battery pack mounting unit  50 B and the battery pack  60  attached to the battery pack mounting unit  50 B lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 B is arranged in the housing upper area HUA and the cover upper area CUA. Particularly, in this embodiment, like in the first embodiment, the battery pack mounting unit  50 B is arranged above the main housing  100 . Therefore, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 B and the battery pack  60  during planing operation. Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 B and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 B and the battery pack  60  in the thickness planer  1 B. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     Further, it may be configured such that the battery pack mounting unit  50 B is fixed to the bottom of the battery pack housing part  410 B in a different orientation from that in this embodiment. For example, the battery pack mounting unit  50 B may be fixed to the bottom of the battery pack housing part  410 B in such an orientation that the battery pack  60  is mounted thereto from the rear or the left or right side of the thickness planer  1 B. 
     The direction in which the battery pack housing part  410 B opens in the top cover  41 B may be changed according to the orientation of the battery pack mounting unit  50 B mounted to the bottom of the battery pack housing part  410 B. For example, when the battery pack mounting unit  50 B is fixed to the bottom of the battery pack housing part  410 B in such an orientation that the battery pack  60  is mounted thereto from the rear of the thickness planer  1 B, the battery pack housing part  410 B may be formed to be open at an upper rear end of the top cover  41 B. When the battery pack mounting unit  50 B is fixed to the bottom of the battery pack housing part  410 B in such an orientation that the battery pack  60  is mounted thereto from the left or right side of the thickness planer  1 B, the battery pack housing part  410 B may be formed to be open at an upper left or right end of the top cover  41 B. 
     The battery pack housing part  410 B may be configured as follows. The battery pack housing part  410 B may be formed into a recessed shape such that part of the top surface of the battery pack  60  attached to the battery pack mounting unit  50 B is visible when viewed from above. Further, the battery pack housing part  410 B may be formed into a recessed shape such that part of the front surface of the battery pack  60  attached to the battery pack mounting unit  50 B is visible when viewed from the front. 
     In this embodiment, the top cover  41 B and the battery pack housing part  410 B may be integrally formed with each other. In this case, the strengths of the top cover  41 B and the battery pack housing part  410 B are improved. Further, in this embodiment, the battery pack housing part  410 B and the battery pack mounting unit  50 B may be integrally formed with each other. In this case, the strengths of the battery pack housing part  410 B and the battery pack mounting unit  50 B are improved. Furthermore, in this embodiment, the top cover  41 B, the battery pack housing part  410 B and the battery pack mounting unit  50 B may be integrally formed with each other. In this case, the strengths of the top cover  41 B, the battery pack housing part  410 B and the battery pack mounting unit  50 B are improved. 
     In this embodiment, it may be configured such that an upper end part of the battery pack  60  attached to the battery pack mounting unit  50 B and housed in the battery pack housing part  410 B does not protrude upward from the upper surface of the top cover  41 B. Thus, the size of a portion of the thickness planer  1 B above the top cover  41 B (the length of the thickness planer  1 B in the vertical direction) is avoided from increasing due to the battery pack mounting unit  50 B and the battery pack  60  being housed in the battery pack housing part  410 B. As a result, the thickness planer  1 B realizes space saving when stored or loaded. 
     Fourth Embodiment 
     A thickness planer  1 C according to a fourth embodiment of the present disclosure is now described with reference to  FIGS. 19 and 20 . A main difference between the thickness planer  1 C of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 C and the battery pack  60  are arranged. 
     The thickness planer  1 C of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 C is arranged in the cover upper area CUA. Further, in this embodiment, a battery pack housing part  410 C is provided on a top cover  41 C and houses at least parts of the battery pack mounting unit  50 C and the battery pack  60  attached to the battery pack mounting unit  50 C. The battery pack housing part  410 C is arranged above the main housing  100 . 
     The battery pack housing part  410 C is formed by a box-like member provided on a top of the top cover  41 C. Further, the battery pack housing part  410 C is formed with an open front end. Specifically, the battery pack housing part  410 C is formed such that the whole front surface of the battery pack  60  attached to the battery pack mounting unit  50 C is visible when viewed from the front. 
     The battery pack mounting unit  50 C is fastened to an upper inner wall of the battery pack housing part  410 C by a plurality of screw parts. The battery pack mounting unit  50 C is mounted to the upper inner wall of the battery pack housing part  410 C in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 C. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 C by being slid rearward with respect to the battery pack mounting unit  50 C from the front of the thickness planer  1 C. Thus, the mounting direction is a direction heading from the front to the rear of the thickness planer  1 C. Further, the battery pack  60  is detached from the battery pack mounting unit  50 C by being slid forward with respect to the battery pack mounting unit  50 C in the thickness planer  1 C. Thus, the removing direction is a direction heading from the rear to the front of the thickness planer  1 C. 
     In such a structure, the unlock button  61   f  of the battery pack  60  can be operated from the front of the thickness planer  1 C. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 C like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. 
     The thickness planer  1 C of this embodiment is configured such that rear end parts of the battery pack mounting unit  50 C and the battery pack  60  are located rearward (inward) of the front end of the closed front auxiliary table  44 . Therefore, the battery pack mounting unit  50 C and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 C. Thus, the thickness planer  1 C is provided with improved storability and portability. 
     As described above, in the thickness planer  1 C according to this embodiment, the battery pack housing part  410 C is provided on the top of the top cover  41 C and houses at least parts of the battery pack mounting unit  50 C and the battery pack  60  attached to the battery pack mounting unit  50 C. Therefore, at least parts of the battery pack mounting unit  50 C and the battery pack  60  attached to the battery pack mounting unit  50 C are protected. For example, the battery pack mounting unit  50 C and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment. 
     Further, the battery pack housing part  410 C has the open front end, which facilitates attachment and detachment of the battery pack  60 . 
     Further, the battery pack mounting unit  50 C is fixed to the upper inner wall of the battery pack housing part  410 C in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 C. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 C like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA, so that convenience of the thickness planer  1 C is improved. 
     In the thickness planer  1 C of this embodiment, the battery pack mounting unit  50 C is fastened to the upper inner wall of the battery pack housing part  410 C by the screw parts. Therefore, the battery pack mounting unit  50 C and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 C. 
     In the thickness planer  1 C according to this embodiment, like in the first embodiment, the battery pack mounting unit  50 C is configured such that the battery pack mounting unit  50 C and the battery pack  60  attached to the battery pack mounting unit  50 C lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 C is arranged in the cover upper area CUA. Particularly, in the thickness planer  1 C according to this embodiment, like in the first embodiment, the battery pack mounting unit  50 C is arranged above the main housing  100 . Therefore, during planing operation, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 C and the battery pack  60 . Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 C and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 C and the battery pack  60  in the thickness planer  1 C. 
     Further, the battery pack mounting unit  50 C and the battery pack  60  are surrounded on the upper and lower sides and the left and right sides by the battery pack housing part  410 C. Therefore, the battery pack mounting unit  50 C and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during planing operation or transportation. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     Further, it may be configured such that the battery pack mounting unit  50 C is fixed to the upper inner wall of the battery pack housing part  410 C in a different orientation from that in this embodiment. For example, the battery pack mounting unit  50 C may be fixed to the upper inner wall of the battery pack housing part  410 C in such an orientation that the battery pack  60  is mounted thereto from the rear or the left or right side of the thickness planer  1 C. 
     The direction in which the battery pack housing part  410 C opens may be changed according to the orientation of the battery pack mounting unit  50 C mounted to the upper inner wall of the battery pack housing part  410 C. For example, when the battery pack mounting unit  50 C is fixed to the upper inner wall of the battery pack housing part  410 C in such an orientation that the battery pack  60  is mounted thereto from the rear of the thickness planer  1 C, the battery pack housing part  410 C may be formed to have an open rear end. When the battery pack mounting unit  50 C is fixed to the upper inner wall of the battery pack housing part  410 C in such an orientation that the battery pack  60  is mounted thereto from the left or right side of the thickness planer  1 C, the battery pack housing part  410 C may be formed to have an open left or right end. 
     The battery pack mounting unit  50 C may be arranged on a lower inner wall of the battery pack housing part  410 C, that is, on top of the top cover  41 C. Alternatively, the battery pack mounting unit  50 C may be arranged on a left or right inner wall of the battery pack housing part  410 C. 
     In this embodiment, the top cover  41 C and the battery pack housing part  410 C may be integrally formed with each other. In this case, the strengths of the top cover  41 C and the battery pack housing part  410 C are improved. Further, in this embodiment, the battery pack housing part  410 C and the battery pack mounting unit  50 C may be integrally formed with each other. In this case, the strengths of the battery pack housing part  410 C and the battery pack mounting unit  50 C are improved. Furthermore, in this embodiment, the top cover  41 C, the battery pack housing part  410 C and the battery pack mounting unit  50 C may be integrally formed with each other. In this case, the strengths of the top cover  41 C, the battery pack housing part  410 C and the battery pack mounting unit  50 C are improved. 
     Fifth Embodiment 
     A thickness planer  1 D according to a fifth embodiment of the present disclosure is now described with reference to  FIGS. 21 and 22 . A main difference between the thickness planer  1 D of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 D and the battery pack  60  are arranged. 
     The thickness planer  1 D of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 D is fastened to a top of the chip cover  350  behind the main housing  100  by a plurality of screw parts. Specifically, the battery pack mounting unit  50 D is arranged in the driving mechanism arrangement area DMA (see  FIG. 3 ). Particularly, in this embodiment, the battery pack mounting unit  50 D is mounted to the top of the chip cover  350  in such an orientation that the battery pack  60  is attached and detached from the rear of the thickness planer  1 D. The battery pack  60  is attached to the battery pack mounting unit  50 D by being slid forward with respect to the battery pack mounting unit  50 D from the rear of the thickness planer  1 D. Thus, the mounting direction is a direction heading from the rear to the front of the thickness planer  1 D. Further, the battery pack  60  is detached from the battery pack mounting unit  50 D by being slid rearward with respect to the battery pack mounting unit  50 D in the thickness planer  1 D. Thus, the removing direction is a direction heading from the front to the rear of the thickness planer  1 D. In such a structure, the unlock button  61   f  of the battery pack  60  can be operated from the rear of the thickness planer  1 D. 
     In this embodiment, an upper end part of the battery pack  60  attached to the battery pack mounting unit  50 D is located below an upper end of the main housing  100 . Therefore, when the body unit  10  is raised up to the highest position, the battery pack  60  can be avoided from getting into contact with a lower surface of a top cover  41 D. 
     The thickness planer  1 D of this embodiment is configured such that rear end parts of the battery pack mounting unit  50 D and the battery pack  60  are located forward (inward) of the rear end of the closed rear auxiliary table  45 . Therefore, the battery pack mounting unit  50 D and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 D. Thus, the thickness planer  1 D is provided with improved storability and portability. 
     As described above, in the thickness planer  1 D according to this embodiment, the battery pack mounting unit  50 D is fastened to the top of the chip cover  350  behind the main housing  100  by a plurality of screw parts. Therefore, the battery pack mounting unit  50 D and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 D. 
     A free space exists above the chip cover  350  behind the main housing  100 . In the thickness planer  1 D according to this embodiment, the battery pack mounting unit  50 D is arranged on the top of the chip cover  350 , so that the free space existing above the chip cover  350  behind the main housing  100  is effectively utilized. 
     In the thickness planer  1 D according to this embodiment, like in the first embodiment, the battery pack mounting unit  50 D is configured such that the battery pack mounting unit  50 D and the battery pack  60  attached to the battery pack mounting unit  50 D lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 D is arranged in the driving mechanism arrangement area DMA. Therefore, during planing operation, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 D and the battery pack  60 . Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 D and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 D and the battery pack  60  in the thickness planer  1 D. 
     In the thickness planer  1 D according to this embodiment, the battery pack mounting unit  50 D is arranged below the top cover  41 . Therefore, the size of a portion of the thickness planer  1 D above the top cover  41  (the length of the thickness planer  1 D in the vertical direction) is avoided from increasing due to arrangement of the battery pack mounting unit  50 D. As a result, the thickness planer  1 D realizes space saving when stored or loaded. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     Further, it may be configured such that the battery pack mounting unit  50 D is fixed to the chip cover  350  in a different orientation from that in this embodiment. For example, the battery pack mounting unit  50 D may be fixed to the chip cover  350  in such an orientation that the battery pack  60  is mounted thereto from the left or right side of the thickness planer  1 D. 
     In this embodiment, the chip cover  350  and the battery pack mounting unit  50 D may be integrally formed with each other. In this case, the strengths of the chip cover  350  and the battery pack mounting unit  50 D are improved. 
     The structure in which the battery pack mounting unit  50 D and the battery pack  60  are arranged on the top of the chip cover  350  may be applied to a thickness planer not having the top cover on the top of the main housing  100 . By provision of such a structure, like in this embodiment, a free space above the chip cover  350  is effectively utilized. 
     Sixth Embodiment 
     A thickness planer  1 E according to a sixth embodiment of the present disclosure is now described with reference to  FIGS. 23 and 24 . A main difference between the thickness planer  1 E of this embodiment and the thickness planer  1  of the first embodiment is the structure and arrangement position of a battery pack mounting unit  50 E. 
     The thickness planer  1 E of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 E is arranged in the left side area LSA. Specifically, a connection terminal  461 E is provided in a lower part of a left side cover  46 E and electrically connected to the motor  15 , and one end of an electric cord  52 E is electrically connected to the connection terminal  461 E. The electric cord  52 E is removably connected to the connection terminal  461 E. The other end of the electric cord  52 E is electrically connected to the battery pack mounting unit  50 E. The battery pack mounting unit  50 E includes a body part  50 E 1  and a lid part  50 E 2 . The lid part  50 E 2  is supported by the body part  50 E 1  so as to be turnable around a pivot shaft  50 E 3 , and can be opened and closed with respect to the body part  50 E 1 . In order to attach and detach the battery pack  60  with respect the battery pack mounting unit  50 E, the lid part  50 E 2  is opened and the battery pack  60  is slid with respect to the body part  50 E 1 . When the lid part  50 E 2  is closed with the battery pack  60  attached to the body part  50 E 1 , the whole battery pack  60  is covered by the body part  50 E 1  and the lid part  50 E 2  Like in the first embodiment, the battery pack mounting unit  50 E is configured such that the battery pack  60  is removably attached thereto. In this embodiment, the battery pack mounting unit  50 E is configured such that two battery packs  60  can be attached thereto so as to be electrically connected in series. 
     In use of the thickness planer  1 E, the battery pack mounting unit  50 E is connected to the connection terminal  461 E via the electric cord  52 E, and the two battery packs  60  are attached to the battery pack mounting unit  50 E. 
     When the thickness planer  1 E is not in use, the electric cord  52 E is removed from the connection terminal  461 E, so that the thickness planer  1 E and the battery pack mounting unit  50 E can be separately stored. 
     In this embodiment, the electric cord  52 E and the battery pack mounting unit  50 E are inseparably connected to each other, but they may be separably connected to each other. 
     As described above, in the thickness planer  1 E according to this embodiment, the battery pack mounting unit  50 E is arranged outside the housing of the thickness planer  1 E, so that the battery pack  60  can be easily attached and detached. 
     The battery pack mounting unit  50 E is arranged in a position avoiding the feeding area TA. More specifically, the battery pack mounting unit  50 E is arranged in the left side area LSA outside the housing of the thickness planer  1 E. Therefore, when the cutter head  21  is taken out of and into the thickness planer  1 E for replacement of the plane blades  213 ,  214 , the battery pack mounting unit  50 E and the battery pack  60  are prevented from interfering with the replacement work, so that the efficiency of the replacement work is improved. Further, the battery pack mounting unit  50 E is separable from the thickness planer  1 E. Therefore, when the battery pack mounting unit  50 E is separated from the thickness planer  1 E, the battery pack mounting unit  50 E and the battery pack  60  do not interfere with the replacement work of replacing the plane blades  213 ,  214 . Thus, the efficiency of the replacement work is further improved. 
     Further, with the structure in which the battery pack mounting unit  50 E is separable from the thickness planer  1 E, the thickness planer  1 E is provided with improved storability and portability. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     The electric cord  52 E and the battery pack mounting unit  50 E may be integrally formed with each other. Further, the electric cord  52 E, the battery pack mounting unit  50 E and the battery pack  60  may be integrally formed with each other as one battery unit. 
     The structure in which the thickness planer  1 E is connected to the battery pack mounting unit  50 E disposed outside the thickness planer  1 E via the electric cord  52 E may be applied to a thickness planer not having the top cover on the top of the main housing. In such a case, the same effects as this embodiment can be obtained. 
     Seventh Embodiment 
     A thickness planer  1 F according to a seventh embodiment of the present disclosure is now described with reference to  FIGS. 25 and 26 . A main difference between the thickness planer  1 F of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 F and the battery pack  60  are arranged. 
     The thickness planer  1 F of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 F is arranged in the driving mechanism arrangement area DMA and the housing upper area HUA. Specifically, the battery pack mounting unit  50 F is mounted to the main housing  100 . Further, the battery pack mounting unit  50 F is configured such that the battery pack  60  moves in the vertical direction as moving in the front-rear direction when the battery pack  60  is slid in a direction (sliding direction) along the rail parts  51   a  of the battery pack mounting unit  50 F. Specifically, the battery pack mounting unit  50 F is mounted to the main housing  100  such that the battery pack  60  slides in an oblique direction with respect to the vertical direction and the front-rear direction. Particularly, in this embodiment, the battery pack mounting unit  50 F is mounted to a rear side of the main housing  100  such that the battery pack  60  is mounted thereto in an obliquely downward direction from the rear to the front. Further, a connection surface of the battery pack mounting unit  50 F for connection to the battery pack  60  faces downward. 
     In the thickness planer  1 F according to this embodiment, the battery pack  60  is attached to the battery pack mounting unit  50 F by being slid forward in the obliquely downward direction from the rear of the thickness planer  1 F, while the battery pack  60  is detached from the battery pack mounting unit  50 F by being slid rearward in an obliquely upward direction in the thickness planer  1 F. 
     In the thickness planer  1 F according to this embodiment, an arch-shaped escape part  420 F is formed in a rear part of a top cover  41 F and facilitates user&#39;s operation of attaching and detaching the battery pack  60 . 
     As described above, in the thickness planer  1 F according to this embodiment, the battery pack mounting unit  50 F is mounted such that the battery pack  60  is mounted thereto in the obliquely downward direction from the rear to the front. The battery pack  60  is attached to the battery pack mounting unit  50 F by being slid forward in the obliquely downward direction from the rear of the thickness planer  1 F. Therefore, a user can attach the battery pack  60  to the battery pack mounting unit  50 F by a natural action of moving a hand in the obliquely downward direction from the user&#39;s front side to the inner depth side. Further, the battery pack  60  is detached from the battery pack mounting unit  50 F by being slid rearward in the obliquely upward direction from the rear of the thickness planer  1 F. Therefore, a user can detach the battery pack  60  from the battery pack mounting unit  50 F by a natural motion of moving a hand in the obliquely upward direction from the inner depth side to the user&#39;s front side. Thus, in the thickness planer  1 F according to this embodiment, attachment and detachment of the battery pack  60  are facilitated. 
     Further, in the thickness planer  1 F according to this embodiment, when the battery pack  60  is detached from the battery pack mounting unit  50 F, the battery pack  60  needs to be slid rearward in the obliquely upward direction from the rear of the thickness planer  1 F. Therefore, the battery pack  60  is avoided from falling off the battery pack mounting unit  50 F during transportation of the thickness planer  1 F. 
     Further, the arch-shaped escape part  420 F is formed in the rear part of the top cover  41 F. Therefore, this embodiment is configured to facilitate the user&#39;s operation of attaching and detaching the battery pack  60 . 
     In this embodiment, the battery pack mounting unit  50 F is configured such that the battery pack mounting unit  50 F and the battery pack  60  attached to the battery pack mounting unit  50 F lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 F and the battery pack  60  are arranged in the driving mechanism arrangement area DMA and the housing upper area HUA. Therefore, during planing operation by a user, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 F and the battery pack  60  while being fed, so that decrease in working efficiency is avoided. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     Further, it may be configured such that the battery pack mounting unit  50 F is mounted to the main housing  100  such that the battery pack  60  is mounted thereto in the obliquely upward direction from the rear to the front. Further, the connection surface of the battery pack mounting unit  50 F for connection to the battery pack  60  may be configured to face upward. Furthermore, the battery pack mounting unit  50 F may be mounted to a front side of the main housing  100 . 
     The structure of the battery pack mounting unit  50 F in this embodiment may be applied to a thickness planer not having the top cover on the top of the main housing. In such a case, the same effects as this embodiment can be obtained. 
     Eighth Embodiment 
     A thickness planer  1 G according to an eighth embodiment of the present disclosure is now described with reference to  FIG. 27 . A main difference between the thickness planer  1 G of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 G and the battery pack  60  are arranged. 
     The thickness planer  1 G of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as in the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawing. 
     In this embodiment, the battery pack mounting unit  50 G is arranged on the left or right side of the main housing  100 . Particularly, in this embodiment, the battery pack mounting unit  50 G is arranged on a left side surface of the left side cover  46 . In other words, the battery pack mounting unit  50 G is arranged in the left side area LSA. Specifically, the battery pack mounting unit  50 G is fastened to the left side surface of the left side cover  46  by a plurality of screw parts. 
     The battery pack mounting unit  50 G is mounted to the left side surface of the left side cover  46  in such an orientation that the battery pack  60  is attached and detached from above on the left side of the thickness planer  1 G. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 G by being slid downward with respect to the battery pack mounting unit  50 G from above the thickness planer  1 G. Thus, the mounting direction is a direction heading from the upper side to the lower side of the thickness planer  1 G. Further, the battery pack  60  is detached from the battery pack mounting unit  50 G by being slid upward with respect to the battery pack mounting unit  50 G in the thickness planer  1 G. Thus, the removing direction is a direction heading from the lower side to the upper side of the thickness planer  1 G. In such a structure, the unlock button  61   f  of the battery pack  60  is operated from the left side of the thickness planer  1 G. 
     As described above, in the thickness planer  1 G according to this embodiment, the battery pack mounting unit  50 G is arranged on the left side surface of the left side cover  46 , so that a user can easily attach and detach the battery pack  60 . 
     In the thickness planer  1 G of this embodiment, the battery pack mounting unit  50 G is fastened to the left side surface of the left side cover  46  by the screw parts. Therefore, the battery pack mounting unit  50 G and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 G. 
     Further, when the battery pack  60  is detached from the battery pack mounting unit  50 G, the battery pack  60  needs to be slid upward with respect to the battery pack mounting unit  50 G in the thickness planer  1 G. Therefore, the battery pack  60  is prevented from falling off the battery pack mounting unit  50 G during transportation of the thickness planer  1 G. 
     In the thickness planer  1 G according to this embodiment, the battery pack  60  is attached and detached by a user on the outside of the left side cover  46 , so that a user&#39;s hand is prevented from approaching the vicinity of the area of the body unit  10  and the vicinity of the cutting area CA. 
     With the structure in which the battery pack mounting unit  50 G is arranged on the left side surface of the left side cover  46 , when the cutter head  21  is taken out of and into the thickness planer  1 G for replacement of the plane blades  213 ,  214 , the battery pack mounting unit  50 G and the battery pack  60  are prevented from interfering with the replacement work, so that the efficiency of the replacement work is improved. 
     In the thickness planer  1 G according to this embodiment, like in the first embodiment, the battery pack mounting unit  50 G is configured such that the battery pack mounting unit  50 G and the battery pack  60  attached to the battery pack mounting unit  50 G lie in a position avoiding the feeding area TA. Particularly, in the thickness planer  1 G according to this embodiment, the battery pack mounting unit  50 G is mounted to the left side surface of the left side cover  46 . Specifically, the battery pack mounting unit  50 G is arranged in the left side area LSA. Therefore, during planing operation, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 G and the battery pack  60 . Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 G and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 G and the battery pack  60  in the thickness planer  1 G. 
     In the thickness planer  1 G according to this embodiment, with the structure in which the battery pack mounting unit  50 G is mounted to the left side surface of the left side cover  46 , a free space on the left side of the left side cover  46  is effectively utilized. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     The battery pack mounting unit  50 G may be arranged on a right side surface of the right side cover  47 . Further, the battery pack mounting unit  50 G may be arranged on the left side surface of the left side cover  46  or the right side surface of the right side cover  47  such that the battery pack  60  is attached to and detached from the battery pack mounting unit  50 G from the front-rear direction. Particularly, the battery pack mounting unit  50 G may be arranged on the left side surface of the left side cover  46  or the right side surface of the right side cover  47  such that the battery pack  60  is attached to the battery pack mounting unit  50 G from the front to rear. 
     In this embodiment, the left side cover  46  or the right side cover  47  and the battery pack mounting unit  50 G may be integrally formed with each other. With this structure, the strengths of the left side cover  46  or the right side cover  47  and the battery pack mounting unit  50 G are improved. 
     The structure in which the battery pack mounting unit  50 G is arranged on the left or right side of the main housing  100  may be applied to a thickness planer not having the top cover on the top of the main housing  100 , or it may be applied to a thickness planer not having the left side cover  46  and the right side cover  47 . In this case, for example, the battery pack mounting unit  50 G may be arranged on the left or right side surface of the main housing  100 . By provision of such a structure, a free space on the left or right side of the main housing  100  is effectively utilized. 
     Ninth Embodiment 
     A thickness planer  1 H according to a ninth embodiment of the present disclosure is now described with reference to  FIGS. 28 and 29 . A main difference between the thickness planer  1 H of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 H and the battery pack  60  are arranged. 
     The thickness planer  1 H of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 H is mounted to a front or rear part of the main housing  100 . In other words, the battery pack mounting unit  50 H is arranged in the driving mechanism arrangement area DMA and the housing upper area HUA. Particularly, in the thickness planer  1 H of this embodiment, the battery pack mounting unit  50 H is arranged on the front of the main housing  100 . Specifically, the battery pack mounting unit  50 H is fastened to the front of the main housing  100  by a plurality of screw parts. 
     The battery pack mounting unit  50 H is mounted to the front of the main housing  100  in such an orientation that the battery pack  60  is attached and detached from above in front of the thickness planer  1 H. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 H by being slid downward from above with respect to the battery pack mounting unit  50 H in front of the thickness planer  1 H. Thus, the mounting direction is a direction heading from the upper side to the lower side of the thickness planer  1 H. Further, the battery pack  60  is detached from the battery pack mounting unit  50 H by being slid upward with respect to the battery pack mounting unit  50 H in the thickness planer  1 H. Thus, the removing direction is a direction heading from the lower side to the upper side of the thickness planer  1 H. 
     In such a structure, the unlock button  61   f  of the battery pack  60  is operated from the front of the thickness planer  1 H. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 H like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. 
     As described above, in the thickness planer  1 H according to this embodiment, the battery pack mounting unit  50 H is arranged on the front of the main housing  100 . Therefore, a user can easily attach and detach the battery pack  60 . Further, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 H like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. Therefore, the thickness planer  1 H according to this embodiment is provided with improved convenience. 
     In the thickness planer  1 H of this embodiment, the battery pack mounting unit  50 H is fastened to the front of the main housing  100  by a plurality of screw parts. Therefore, the battery pack mounting unit  50 H and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 H. 
     Further, when the battery pack  60  is detached from the battery pack mounting unit  50 H, the battery pack  60  needs to be slid upward with respect to the battery pack mounting unit  50 H in the thickness planer  1 H. Therefore, the battery pack  60  is prevented from falling off the battery pack mounting unit  50 H during transportation of the thickness planer  1 H. 
     With the structure in which the battery pack mounting unit  50 H is arranged on the front of the main housing  100 , when the cutter head  21  is taken out of and into the thickness planer  1 H for replacement of the plane blades  213 ,  214 , the battery pack mounting unit  50 H and the battery pack  60  are prevented from interfering with the replacement work, so that the efficiency of the replacement work is improved. 
     In the thickness planer  1 H according to this embodiment, like in the first embodiment, the battery pack mounting unit  50 H is configured such that the battery pack mounting unit  50 H and the battery pack  60  attached to the battery pack mounting unit  50 H lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 H and the battery pack  60  are arranged in the driving mechanism arrangement area DMA and the housing upper area HUA. Particularly, in the thickness planer  1 H according to this embodiment, the battery pack mounting unit  50 H is mounted to the front of the main housing  100 . Therefore, during planing operation, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 H and the battery pack  60 . Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 H and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 H and the battery pack  60  in the thickness planer  1 H. 
     In the thickness planer  1 H according to this embodiment, with the structure in which the battery pack mounting unit  50 H is mounted to the front of the main housing  100 , a free space in front of the main housing  100  is effectively utilized. 
     The battery pack mounting unit  50 H may be arranged on the rear of the main housing  100 . Further, in this embodiment, the main housing  100  and the battery pack mounting unit  50 H may be integrally formed with each other. With this structure, the strengths of the main housing  100  and the battery pack mounting unit  50 H are improved. 
     The structure in which the battery pack mounting unit  50 H is arranged on the front or rear of the main housing  100  may be applied to a thickness planer not having the top cover on the top of the main housing  100 . By provision of such a structure, a free space in front of or behind the main housing  100  is effectively utilized. 
     Tenth Embodiment 
     A thickness planer  1 I according to a tenth embodiment of the present disclosure is now described with reference to  FIGS. 30 to 32 . A main difference between the thickness planer  1 I of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 I and the battery pack  60  are arranged. 
     The thickness planer  1 I of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as thickness planer  1 . Therefore, in the following description, the same structures as the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 I is supported by the left side cover  461  so as to be turnable around a pivot shaft  53 I extending in the vertical direction. The battery pack mounting unit  50 I is configured to be turned between a first side area (inner area) of the left side cover  461  which faces the main housing  100  and a second side area (outer area) on the opposite side to the first side area. Specifically, the battery pack mounting unit  50 I is arranged in the driving mechanism arrangement area DMA and the housing upper area HUA, or in the left side area LSA. 
     In the following description, a state (shown in  FIG. 31 ) in which the battery pack mounting unit  50 I is located in the first side area (the driving mechanism arrangement area DMA and the housing upper area HUA) by turning around the pivot shaft  53 I is defined as a first turning state, while a state (shown in  FIG. 32 ) in which the battery pack mounting unit  50 I is located in the second side area (the left side area LSA) by turning around the pivot shaft  53 I is defined as a second turning state. 
     When transporting or storing the thickness planer  1 I, a user places the battery pack mounting unit  50 I in the first turning state, while, when using the thickness planer  1 I or attaching and detaching the battery pack  60 , the user places the battery pack mounting unit  50 I in the second turning state. 
     In the second turning state, the battery pack mounting unit  50 I is supported on the left side cover  461  by the pivot shaft  53 I such that the rail parts  51   a , the positive input terminal  51   b  and the negative input terminal  51   c  face forward. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 I. 
     In the second turning state, the battery pack mounting unit  50 I is supported on the left side cover  461  by the pivot shaft  53 I in such an orientation that the battery pack  60  is attached and detached from above the thickness planer  1 I. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 I by being slid downward from above the thickness planer  1 I with respect to the battery pack mounting unit  50 I. Thus, the mounting direction is a direction heading from the upper side to the lower side of the thickness planer  1 I. Further, the battery pack  60  is detached from the battery pack mounting unit  50 I by being slid upward with respect to the battery pack mounting unit  50 I in the thickness planer  1 I. Thus, the removing direction is a direction heading from the lower side to the upper side of the thickness planer  1 I. 
     As shown in  FIG. 30 , in the first turning state, the battery pack mounting unit  50 I is located behind the main housing  100  above the chip cover  350 . Further, in this embodiment, it is configured such that rear end parts of the battery pack mounting unit  50 I and the battery pack  60  in the first turning state are located forward (inward) of the rear end of the closed rear auxiliary table  45 . Therefore, the battery pack mounting unit  50 I and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 I. 
     As described above, in the thickness planer  1 I according to this embodiment, the battery pack mounting unit  50 I in the second turning state is supported on the left side cover  461  by the pivot shaft  53 I such that the rail parts  51   a , the positive input terminal  51   b  and the negative input terminal  51   c  face forward. Therefore, a user can easily attach and detach the battery pack  60  from the front of the thickness planer  1 I. Further, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 I like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CM. Therefore, the thickness planer  1 I according to this embodiment is provided with improved convenience. 
     Like in the first embodiment, the battery pack mounting unit  50 I in the second turning state is configured such that the battery pack mounting unit  50 I and the battery pack  60  attached to the battery pack mounting unit  50 I lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 I is arranged in the left side area LSA. Particularly, in the thickness planer  1 I according to this embodiment, the battery pack mounting unit  50 I in the second turning state is located on the left side of the left side cover  461 . Therefore, during planing operation by a user, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 I and the battery pack  60  while being fed, so that decrease in working efficiency is avoided. Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 I and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 I and the battery pack  60  in the thickness planer  1 I. 
     With the structure in which the battery pack mounting unit  50 I in the second turning state is located on the left side of the left side cover  461 , when the cutter head  21  is taken out of and into the thickness planer  1 I for replacement of the plane blades  213 ,  214 , the battery pack mounting unit  50 I and the battery pack  60  are prevented from interfering with the replacement work, so that the efficiency of the replacement work is improved. 
     In the thickness planer  1 I according to this embodiment, it is configured such that the rear end parts of the battery pack mounting unit  50 I and the battery pack  60  in the first turning state are located forward (inward) of the rear end of the closed rear auxiliary table  45 . Therefore, the battery pack mounting unit  50 I and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 I. Thus, the thickness planer  1 I of this embodiment is provided with improved storability and portability. 
     In the thickness planer  1 I according to this embodiment, with the structure in which the battery pack mounting unit  50 I is supported on the left side cover  461  by the pivot shaft  53 I, the battery pack mounting unit  50 I and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 I. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     Further, the battery pack mounting unit  50 I may be supported on the right side cover  471  so as to be turnable around the pivot shaft  53 I. 
     Eleventh Embodiment 
     A thickness planer  1 J according to an eleventh embodiment of the present disclosure is now described with reference to  FIGS. 33 and 34 . A main difference between the thickness planer  1 J of this embodiment and the thickness planer  1  of the first embodiment is a position where a battery pack mounting unit  50 J and the battery pack  60  are arranged. 
     The thickness planer  1 J of this embodiment is configured to plane a workpiece CM like the thickness planer  1  of the first embodiment and includes the same structures as the thickness planer  1 . Therefore, in the following description, the same structures as the thickness planer  1  are given like numerals and are not or briefly described, and different structures are mainly described with reference to the drawings. 
     In this embodiment, the battery pack mounting unit  50 J is arranged below the table  43 , that is, in the base area BSA. Specifically, the battery pack mounting unit  50 J is arranged in a front part of a lower side area of a base  80 J. Particularly, in this embodiment, the battery pack mounting unit  50 J is fastened to a lower surface of the base  80 J by a plurality of screw parts. An opening  83 J is formed in a front side of the base  80 J. The battery pack mounting unit  50 J is mounted to the lower surface of the base  80 J in such an orientation that the battery pack  60  is attached and detached from the front of the thickness planer  1 J. Specifically, the battery pack  60  is attached to the battery pack mounting unit  50 J by being slid rearward from the front of the thickness planer  1 J with respect to the battery pack mounting unit  50 J. Thus, the mounting direction is a direction heading from the front to the rear of the thickness planer  1 J. Further, the battery pack  60  is detached from the battery pack mounting unit  50 J by being slid forward with respect to the battery pack mounting unit  50 J in the thickness planer  1 J. Thus, the removing direction is a direction heading from the rear to the front of the thickness planer  1 J. 
     In such a structure, the unlock button  61   f  of the battery pack  60  is operated from the front of the thickness planer  1 J. Therefore, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 J like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. 
     In this embodiment, it is configured such that rear end parts of the battery pack mounting unit  50 J and the battery pack  60  are located rearward (inward) of the rear end of the closed front auxiliary table  44 . Therefore, the battery pack mounting unit  50 J and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 J. 
     As described above, in the thickness planer  1 J according to this embodiment, a user can easily attach and detach the battery pack  60  from the front of the thickness planer  1 J. Further, a user can attach and detach the battery pack  60  from the front of the thickness planer  1 J like in operating the main switch  71  and the lever switch  72  and in feeding the workpiece CM to the cutting area CA. Therefore, the thickness planer  1 J according to this embodiment is provided with improved convenience. 
     Like in the first embodiment, the battery pack mounting unit  50 J is configured such that the battery pack mounting unit  50 J and the battery pack  60  attached to the battery pack mounting unit  50 J lie in a position avoiding the feeding area TA. Specifically, the battery pack mounting unit  50 J is arranged in the base area BSA. Particularly, in this embodiment, the battery pack mounting unit  50 J is arranged in the lower side area of the base  80 J. Therefore, during planing operation by a user, the workpiece CM is avoided from getting into contact with the battery pack mounting unit  50 J and the battery pack  60  while being fed, so that decrease in working efficiency is avoided. Further, the user&#39;s view of the cutter head  21  (or the cutting area CA) is avoided from being obstructed by the battery pack mounting unit  50 J and the battery pack  60 , so that a user can easily check how the workpiece CM is being planed. As a result, the working efficiency of a user is prevented from lowering due to provision of the battery pack mounting unit  50 J and the battery pack  60  in the thickness planer  1 J. 
     With the structure in which the battery pack mounting unit  50 J is arranged in the lower side area of the base  80 J, when the cutter head  21  is taken out of and into the thickness planer  1 J for replacement of the plane blades  213 ,  214 , the battery pack mounting unit  50 J and the battery pack  60  are prevented from interfering with the replacement work, so that the efficiency of the replacement work is improved. 
     It is configured such that rear end parts of the battery pack mounting unit  50 J and the battery pack  60  are located forward (inward) of the front end of the closed front auxiliary table  44 . Therefore, the battery pack mounting unit  50 J and the battery pack  60  are avoided from getting into contact with external elements such as a user and surrounding equipment during transportation or storage of the thickness planer  1 J. Thus, the thickness planer  1 J of this embodiment is provided with improved storability and portability. 
     In the thickness planer  1 J according to this embodiment, with the structure in which the battery pack mounting unit  50 J is fastened to the lower surface of the base  80 J by the screw parts, the battery pack mounting unit  50 J and the battery pack  60  are prevented from falling off during transportation of the thickness planer  1 J. 
     Further, in this embodiment, the battery pack mounting unit  50 J is arranged below the table  43 , so that a free space below the table  43  is effectively utilized. 
     In this embodiment, other effects similar to those of the above-described first embodiment are also obtained by provision of the same structures and methods as in the first embodiment. 
     The battery pack mounting unit  50 J may be arranged in a rear part of the lower side area of the base  80 J. Further, the battery pack mounting unit  50 J may be mounted to the lower surface of the base  80 J in such an orientation that the battery pack  60  is attached and detached from the rear of the thickness planer  1 J. 
     The structure in which the battery pack mounting unit  50 J is arranged below the table  43  may be applied to a thickness planer in which the table can be raised and lowered in the vertical direction respect to the base, or it may be applied to a thickness planer not having the top cover on the top of the main housing. In this case, the same effects as in this embodiment can also be obtained by arranging the battery pack mounting unit in the lower side area of the base like in this embodiment. 
     According to the above-described embodiments, the thickness planer is configured such that the battery pack  60  is removably attached thereto, but it may be configured otherwise. For example, the thickness planer may be configured such that the battery pack  60  is unremovably attached thereto. Specifically, the thickness planer may be provided with a built-in battery pack. The battery pack mounting unit may include a fixing metal fitting and a screw part for unremovably attaching the battery pack to the thickness planer, or other members necessary to attach the battery pack to the thickness planer. Further, in this case, the thickness planer may be configured such that the battery pack mounting unit and the battery pack attached to the battery pack mounting unit lie in a position avoiding the feeding area TA through which the workpiece CM passes when fed to a planing part by a feeding part. 
     According to the above-described embodiments, the battery pack mounting unit is configured such that two battery packs can be attached thereto, but it may be configured otherwise. The battery pack mounting unit may be configured such that one or three or more battery packs can be attached thereto. 
     According to the above-described embodiments, the thickness planer is configured such that a plurality of battery packs attached to the battery pack mounting unit are electrically connected in series to the motor, but it may be configured otherwise. For example, it may be configured such that the battery packs attached to the battery pack mounting unit are electrically connected in parallel to the motor. 
     According to the above-described embodiments, the thickness planer is configured such that the workpiece is fed in one direction, but it may be configured otherwise. For example, the thickness planer may be configured such that the workpiece is fed in both directions. 
     (Correspondences) 
     Correspondences between the features of the above-described embodiments and the features of the invention are as follows. The thickness planer  1 ,  1 A,  1 B,  1 C,  1 D,  1 E,  1 F,  1 G,  1 H,  1 I,  1 J is an example embodiment that corresponds to the “thickness planer” according to the present invention. The workpiece CM is an example embodiment that corresponds to the “workpiece” according to the present invention. The motor  15  is an example embodiment that corresponds to the “motor” according to the present invention. The cutter head  21  is an example embodiment that corresponds to the “planing part” according to the present invention. The table  43 , the front auxiliary table  44  and the rear auxiliary table  45  are example embodiments that correspond to the “placing part” according to the present invention. The feed roller  31 ,  33  is an example embodiment that corresponds to the “feeding part” according to the present invention. The battery pack  60  is an example embodiment that corresponds to the “battery pack” according to the present invention. The battery pack mounting unit  50 ,  50 A,  50 B,  50 C,  50 D,  50 E,  50 F,  50 G,  50 H,  50 I,  50 J and the members necessary to unremovably attach the battery pack to the thickness planer are example embodiments that correspond to the “battery pack mounting unit” according to the present invention. The feeding area TA is an example embodiment that corresponds to the “feeding area” according to the present invention. The main housing  100  is an example embodiment that corresponds to the “motor housing” according to the present invention. The top cover  41 ,  41 A,  41 B,  41 F is an example embodiment that corresponds to the “cover part” according to the present invention. The battery pack housing part  410 B,  410 C is an example embodiment that corresponds to the “battery pack housing part” according to the present invention. The chip cover  350  is an example embodiment that corresponds to the “scattering prevention part” according to the present invention. The top cover  41 , the left side cover  46 , the right side cover  47  and the base  80  are example embodiments that correspond to the “housing forming the thickness planer” according to the present invention. The electric cord  52 ,  52 E is an example embodiment that correspond to the “energizing member” according to the present invention. The left side cover  46 ,  46 E and the right side cover  47  are example embodiments that correspond to the “side member” according to the present invention. The first side area (inner area) is an example embodiment that corresponds to the “first side area” according to the present invention. The second side area (outer area) is an example embodiment that corresponds to the “second side area” according to the present invention. The pivot shaft  53 I is an example embodiment that corresponds to the “pivot shaft around which the battery pack mounting unit is configured to be turnable between a first side area and a second side area on the opposite side to the first side area” according to the present invention. 
     DESCRIPTION OF THE NUMERALS 
       1 ,  1 A to  1 J: thickness planer,  10 : body unit,  15 : motor,  19 : residual capacity display part,  21 : cutter head,  30 : main frame,  31 ,  33 : feed roller,  41 ,  41 A to  41 D,  41 F: top cover,  43 : table,  44 : front auxiliary table,  45 : rear auxiliary table,  46 ,  46 E,  461 : left side cover,  47 ,  471 : right side cover,  48 : lifting handle,  50 ,  50 A to  50 J: battery pack mounting unit,  51 : mounting part,  51   a : rail part,  51   b : positive input terminal,  51   c : negative input terminal,  51   e : lock receiving hole,  52 ,  52 E: electric cord,  53 I: pivot shaft,  60 : battery pack,  61   a : rail receiving part,  61   b : positive output terminal,  61   c : negative output terminal,  61   d : connector part,  61   e : lock member,  61   f : unlock button,  71 : main switch,  72 : lever switch,  80 : base,  80 J: base,  83 J: opening,  100 : main housing,  110 : first housing,  112 : controller,  114 : control board,  115 : transistor,  118 : right end wall part,  121 : intake port,  125 : outlet port,  145 : chip discharge port,  151 : stator,  152 : rotor,  153 : motor shaft,  154 ,  155 : bearing,  156 : fan,  157 : pulley,  160 : second housing,  161 ,  162 ,  163 : gear,  164 : drive shaft,  166 : gear,  180 : third housing,  191 ,  192 : residual capacity gauge,  201 : belt,  211 : pulley,  213 ,  214 : planer blade,  215 : screw part,  301 : chain,  311 : shaft,  312 : gear,  313 : roller part,  331 : shaft,  332 : gear,  333 : roller part,  341 ,  342 ,  343 ,  344 : slide part,  345 ,  346 : lifting screw hole part,  350 : chip cover,  351 : screw part,  352 : screw part,  410 B,  410 C: battery pack housing part,  411 ,  412 ,  413 ,  414 : column,  415 ,  416 ,  417 ,  418 : screw part,  420 : escape part,  420 A: escape part,  420 F: escape part,  431 : placing surface,  441 : placing surface,  451 : placing surface,  461 E: connection terminal,  481 : operation part,  483 : pivot shaft,  485 ,  486 : lifting screw shaft, CM: workpiece, CA: cutting area, TA: feeding area, CUA: cover upper area, HUA: housing upper area, DMA: driving mechanism arrangement area, BSA: base area, LSA: left side area, RSA: right side area