Patent Publication Number: US-11642763-B2

Title: Ratchet wrench

Description:
RELATED APPLICATIONS 
     This application is a Continuation Application of U.S. patent application Ser. No. 16/633,103, filed Jan. 22, 2020, which in turn claims the benefits of International Application No. PCT/JP2018/027748, filed on Jul. 24, 2018, which claims the benefit of Japanese Patent Application No. 2017-150941, filed on Aug. 3, 2017, the entirety of which is incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The invention relates to an electric or air-driven ratchet wrench. 
     BACKGROUND ART 
     There has been known an electric ratchet wrench, which is also used manually, used to, for example, fasten a nut and a bolt as described in Japanese Laid Open Patent Publication No. 7-124871. 
     In the electric ratchet wrench, upper and lower end portions of a cylindrical socket rotatably supported to a distal end of a housing in a state where the socket is exposed on both upper and lower sides are held to a ratchet holder performing a reciprocating rotation operation. The socket has an outer peripheral surface where a sawtooth surface formed by arranging a ridge group having a mountain shape in cross section in parallel across the whole circumference is formed. Further, a ratchet claw that meshes with the sawtooth surface on the socket so as to allow a rotation in a free direction and restrict a rotation in a lock direction, which is a direction opposite to the free direction, is disposed outside the socket. 
     In the electric ratchet wrench, the reciprocating rotation operation by the ratchet holder in a state where the nut or the like is inserted into an upper half portion or a lower half portion of the socket progresses the fastening of the nut or the like via the socket. The action of the ratchet claw to the sawtooth surface intermittently progresses the fastening of the nut or the like in the lock direction each time the ratchet holder performs the reciprocating rotation operation, and the socket idles to the ratchet holder in the free direction. 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     With the above-described electric ratchet wrench, the meshing of the ratchet claw with the sawtooth surface on the socket achieves the lock direction and the free direction. Therefore, to improve strength of the lock, the ratchet claw and the sawtooth need to be increased in size, and there is a limit on achieving both compactability and a performance, such as the strength of lock and reliability of the operation. 
     Additionally, with the above-described electric ratchet wrench, the free direction and the lock direction are fixed. Accordingly, to switch these directions to the opposite directions substantially, it is necessary to reverse the electric ratchet wrench with respect to the nut or the like to change the insertion of the nut or the like from the inside of the lower half portion to the inside of the upper half portion of the socket or vice versa, requiring a lot of labor. 
     Additionally, with the above-described electric ratchet wrench, in a case where the nut or the like can be inserted only from the lower side due to, for example, a member being disposed on the upper side of the socket, the free direction and the lock direction cannot be switched to the opposite directions. 
     The main object of the invention is to provide a ratchet wrench achieving both compactability and a lock performance. 
     Additionally, the main object of the invention is to provide the ratchet wrench having further better operability regarding switching of a lock direction. 
     Further, the main object of the invention is to provide the ratchet wrench that performs the switching of the lock direction with more certainty. 
     Solutions to the Problems 
     An invention according to first aspect is a ratchet wrench that includes an electric or air-driven motor, a holder, and reciprocating motion conversion mechanism. The holder rotatably holds a tool bit or a tool bit holder via a one-way clutch mechanism. The reciprocating motion conversion mechanism is configured to convert a driving force from the motor into a reciprocating rotation motion of the holder. A space is provided between the tool bit or the tool bit holder and the holder. The space includes large interval portions and small interval portions. The small interval portions are adjacent to the large interval portions in a rotation direction of the tool bit or the tool bit holder. The small interval portions have distances smaller than distances of the large interval portions. The one-way clutch mechanism includes locking members disposed in the space. The locking member has a size equal to or less than the distance of the large interval portion and exceeding the distance of the small interval portion. 
     An invention according to second aspect, which is in the above-described invention, the locking member may include a pair of planar portions and a pair of bulge portions. The pair of planar portions may be arranged in a direction that the small interval portion is disposed viewed from the large interval portion. The pair of bulge portions may couple between end portions of the planar portions. A size between the pair of bulge portions may be equal to or less than the distance of the large interval portion and exceeding the distance of the small interval portion. 
     An invention according to third aspect, which is in the above-described invention, the pair of the planar portions may be parallel to one another. 
     An invention according to fourth aspect which is in the above-described invention, the pair of planar portions may have a posture of expanding toward the tool bit or the tool bit holder. 
     An invention according to fifth aspect, which is in the above-described invention, the locking member may be at least one ball. 
     An invention according to sixth aspect is a ratchet wrench that includes an electric or air-driven motor, a holder, and reciprocating motion conversion mechanism. The holder rotatably holds a tool bit or a tool bit holder via a one-way clutch mechanism. The reciprocating motion conversion mechanism is configured to convert a driving force from the motor into a reciprocating rotation motion of the holder. A space is provided between the tool bit or the tool bit holder and the holder. The space includes large interval portions and small interval portions. The small interval portions are adjacent to the large interval portions in a rotation direction of the tool bit or the tool bit holder. The small interval portions have distances smaller than distances of the large interval portions. The one-way clutch mechanism includes columnar or cylindrical locking members disposed in the space. The locking member has a diameter having a size equal to or less than the distance of the large interval portion and exceeding the distance of the small interval portion. 
     In an invention according to seventh aspect, which is in the above-described invention, the small interval portions may be disposed on both sides of the large interval portion. A retainer may be disposed between the tool bit or the tool bit holder and the holder. The retainer may be configured to change the spaces of the one small interval portion and the large interval portion to the spaces of another of the small interval portion and the large interval portion. 
     An invention according to eighth aspect, which is in the above-described invention, the retainer may include a protrusion. A direction switching lever including a cam portion in contact with the protrusion may be disposed on one of the holder and the tool bit or the tool bit holder. 
     An invention according to ninth aspect, which is in the above-described invention, in the retainer, springs that bias the locking member in a direction where the small interval portions are disposed viewed from the large interval portions may be disposed. 
     In an invention according to tenth aspect, which is in the above-described invention, a plurality of the spaces may be disposed in a state where arrangements of the small interval portions relative to the large interval portions in the rotation direction are similar to one another. The locking members may be disposed in the respective spaces. 
     In an invention according to eleventh aspect which is in the above-described invention, the tool bit or the tool bit holder may have an outer surface formed into a side surface shape of a regular polygonal prism. The holder may have an inner surface formed into a cylindrical surface shape. 
     Effects of the Invention 
     The main effect of the invention is to provide a ratchet wrench achieving both compactability and a lock performance. 
     Additionally, the main effect of the invention is to provide the ratchet wrench having further better operability regarding switching of a lock direction. 
     Further, the main effect of the invention is to provide the ratchet wrench that performs the switching of the lock direction with more certainty. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an electric ratchet wrench according to a first embodiment of the invention from an upper rear. 
         FIG.  2    is a right side view of  FIG.  1   . 
         FIG.  3    is a center vertical cross-sectional view of  FIG.  1   . 
         FIG.  4    is a partial enlarged view of  FIG.  3   . 
         FIG.  5    is a top view of  FIG.  1   . 
         FIG.  6    is a perspective view of a one-way clutch mechanism of  FIG.  1    and its peripheral area. 
         FIG.  7    is an exploded perspective view of  FIG.  6    and its peripheral area viewed from a left lower side. 
         FIG.  8    is an exploded perspective view of  FIG.  6    and its peripheral area viewed from a left upper side. 
         FIG.  9    is a cross-sectional view taken along the line A-A of  FIG.  2   . 
         FIG.  10 A  is an enlarged view of a front right portion of  FIG.  9    and a drawing when an operating unit of a direction switching lever is on a right side. 
         FIG.  10 B  is an enlarged view of a front right portion of  FIG.  9    and a drawing when an operating unit of a direction switching lever is on a left side. 
         FIG.  11    is a cross-sectional view taken along the line B-B of  FIG.  5   . 
         FIG.  12    is a cross-sectional view taken along the line C-C of  FIG.  3   . 
         FIG.  13 A  is an enlarged view of a front portion of  FIG.  12    and a drawing when the operating unit of the direction switching lever is on a right side. 
         FIG.  13 B  is an enlarged view of a front right portion of  FIG.  12    and a drawing when an operating unit of a direction switching lever is on a left side. 
         FIG.  14 A  is an enlarged view similar to  FIG.  10 A  and a drawing when an operating unit of a direction switching lever is on a right side according to a second embodiment of the invention.  FIG.  14 B  is an enlarged view similar to  FIG.  10 B  and a drawing when an operating unit of a direction switching lever is on a left side according to a second embodiment of the invention. 
         FIG.  15 A  is an enlarged view similar to  FIG.  10 A  and a drawing when an operating unit of a direction switching lever is on a right side according to a third embodiment of the invention. 
         FIG.  15 B  is an enlarged view similar to  FIG.  10 B  and a drawing when an operating unit of a direction switching lever is on a left side according to a third embodiment of the invention. 
         FIG.  16 A  is an exploded perspective view of a retainer and balls of an electric ratchet wrench according to a fourth embodiment of the invention when viewed from a left upper side. 
         FIG.  16 B  is an exploded perspective view of a retainer and balls of an electric ratchet wrench according to a fourth embodiment of the invention when viewed from a left lower side. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following describes embodiments of the invention and their modification examples based on the drawings as necessary. 
     Front and rear, up and down, and right and left in the embodiments and the modification examples are defined for a convenience of explanation and may change according to a situation of a work, a state of a moving member, and the like. 
     It should be noted that the invention is not limited to the following embodiments and modification examples. 
     First Embodiment 
       FIG.  1    is an example of a straight type electric power tool and a perspective view of an electric ratchet wrench  1  according to the first embodiment of the invention, which is an example of a ratchet wrench, in a battery separated state from an upper rear.  FIG.  2    is a right side view of the electric ratchet wrench  1  in a battery mounted state (the same applies to the following).  FIG.  3    is a center vertical cross-sectional view (a battery  10 , a controller  61 , a switch  62 , and a motor  16  are not in cross section) of the electric ratchet wrench  1 .  FIG.  4    is a partial enlarged view of  FIG.  3   . 
     The electric ratchet wrench  1  includes a housing  2  forming its casing. 
     The electric ratchet wrench  1  includes, in an order from a rear side to a front side, a battery mounting portion  12  to which the battery  10  is mounted, a handle portion  14  gripped by a user, a power unit  18  including the motor  16 , a power transmission unit  24  including a planetary gear mechanism  20  and a spindle  22 , and an output unit  32  including a holder  26  and a socket  28  and a one-way clutch mechanism  30  interposed between the holder  26  and the socket  28 . 
     In the electric ratchet wrench  1 , these main components (especially the motor  16 , the planetary gear mechanism  20 , and the spindle  22 ) are linearly arranged, serving as an electric power tool (straight type electric power tool) having one rod shape or an “I” shape as a whole. 
     The motor  16  is a driving source of the electric ratchet wrench  1 . A rotation of the motor  16  is transmitted to the holder  26  in a state where deceleration and reciprocating motion conversion are performed by the planetary gear mechanism  20  and the spindle  22  as a power transmission mechanism, and the socket  28  as a tool bit holder slides to idle relative to the rotation of the holder  26  in a predetermined direction (free direction) via the one-way clutch mechanism  30 . A rotation of the holder  26  in a lock direction, a direction opposite to the free direction, is output so as to lock and rotate together with the socket  28 . 
     To the socket  28 , a socket adapter  34  as a tool bit is mountable in a state where a direction of its center axis (output axis O) is in an up-down direction. The socket adapter  34  includes a hexagonal nut-shaped joint portion  34   a , a flange portion  34   b  on a lower side of the joint portion  34   a , and a quadrilateral driving portion  34   c  on a lower side of the flange portion  34   b . The joint portion  34   a  is put into the socket  28 . Various kinds of exchange sockets (not illustrated) are mounted to the quadrilateral driving portion  34   c , which protrudes downward from the socket  28 , and insertion of a bolt and a nut into the exchange socket, for example, fastens these components. The output axis O as a center axis from an upper end through a lower end of the socket adapter  34  or its extended line is in a direction (up-down direction) intersecting with a machine axis M in a front-rear direction as a center axis of the main components (especially the motor  16 , the planetary gear mechanism  20 , and the spindle  22 ) or its extended line, and protrudes downward in the quadrilateral driving portion  34   c . Here, the machine axis M (or its extended line) and the output axis O (or its extended line) are orthogonal to one another. 
     Since the direction of the machine axis M intersects with the direction of the output axis O, the electric ratchet wrench  1  is a kind of an angle electric power tool. It should be noted that the exchange socket may be handled as the tool bit, and the socket adapter  34  may be handled as the tool bit holder. 
     The housing  2  includes a main body housing  40  and a gear housing  42 . The main body housing  40  serves as a casing of the battery mounting portion  12 , the handle portion  14 , the power unit  18 , and a rear half portion of the power transmission unit  24 , and the gear housing  42  serves as a casing of the power transmission unit  24  and the output unit  32 . 
     It should be noted that the arrangement of various kinds of members in the various kinds of housings and cases appropriately includes a case where a part of the member is in the housing and the case and the remaining part projects or is exposed from the housing and the case, in addition to a case where the members are completely in the housing and the case. Additionally, such an arrangement appropriately includes a case where the members are indirectly supported, in addition to a case where the members are directly supported to the housing and the case. 
     The main body housing  40  is laterally halved and includes a left main body housing  44  and a right main body housing  45 . The left main body housing  44  includes a plurality of screw boss portions  46 , and the right main body housing  45  includes screw-holes corresponding to the respective screw boss portions  46 . The left main body housing  44  and the right main body housing  45  are mated with a plurality of screws  48  each inserted into the pair of the screw-hole and the screw boss portion  46 . 
     The gear housing  42  is a loupe-shaped member made of metal. A handle-shaped portion  50  at the rear of the loupe-shaped portion has a cylindrical shape and has a front diameter-expanded portion having an expanded diameter and a rear diameter-expanded portion having a further expanded diameter at its rear portion. Additionally, a frame-shaped portion  52  at a front portion of the loupe-shaped portion has a forked shape that projects from the front portion of the handle-shaped portion  50  to expand forward like a trumpet shape and further each project forward from the top and the bottom, and each projection has a rounded frame. 
     The handle-shaped portion  50  has a rear portion interposed into a front end portion of the main body housing  40 , and thus the gear housing  42  is coupled to the main body housing  40 . The diameter-expanded portions (especially the rear diameter-expanded portion) of the handle-shaped portion  50  avoid the gear housing  42  to come off forward. 
     The battery  10  is a 10.8V (bolt) lithium-ion battery that contains eight cells as rechargeable cells (not illustrated) in a rectangular parallelepiped-shaped battery case made of resin. The cell has a columnar shape long in an axis direction and directed in a longitudinal direction of the battery case. The battery  10  is rechargeable, and the electric ratchet wrench  1  is a rechargeable ratchet wrench. 
     The battery  10  has a plurality of groove portions (not illustrated) extending in the longitudinal direction formed on one surface (wide surface) of the battery case. In each groove portion, a battery terminal electrically coupled to the cell is disposed to be exposed in the groove portion. It should be noted that the battery terminal is not limited to be installed in the groove portion and, for example, may project or be biased during mounting. 
     Additionally, a microcomputer (not illustrated) is built into the battery  10 . The microcomputer controls an operation of the battery  10 , such as a supply of electric power from the cell to the battery terminal. 
     Groove-shaped rail guides  54  having a longitudinal direction in the front-rear direction are disposed on right and left of the battery case of the battery  10  when the battery terminals are faced downward. 
     Additionally, the battery  10  includes a battery claw  55  configured to project in a state of being biased from an installation surface in a projection direction on a side edge of the installation surface of the battery terminals. The battery claw  55  is integrated with a battery lever (not illustrated) disposed on a surface adjacent to the installation surface of the battery terminals and a surface close to the battery claw  55 . An operation of the battery lever allows the battery claw  55  to sink into the battery case against a biasing force. 
     Further, the battery  10  includes a battery state display unit  56  and a button (not illustrated). The battery state display unit  56  displays a state of the battery  10 , such as an amount of charge (remaining capacity) of the battery  10 , on a surface on a side opposite to the battery lever. The battery state display unit  56  includes a plurality of (four) lamps (not illustrated) arranged in the longitudinal direction on the installation surface. When the button is pressed, the microcomputer lights up the lamps by the number according to the current remaining capacity in the battery state display unit  56  from one end side for a predetermined period. Additionally, when the remaining capacity is equal to or less than a predetermined threshold and therefore the charging is required, the microcomputer flashes one lamp on the one end side of the battery state display unit  56  for a predetermined period. Further, when the battery  10  has a failure, such as a current value between the cell and the battery terminal in excess of a predetermined threshold, the microcomputer flashes two lamps on one end side and two lamps on the other end side in alternation. 
     It should be noted that the battery state display unit  56  is variously changeable. The battery state display unit  56  may be a seven-segment type display unit, the button may be omitted and the display may be performed, for example, while the battery  10  is mounted, at least one of the flash display for charging and the failure display may be omitted, the display may be continued until the button is pressed again or a second button disposed separately is pressed, another state of the battery may be displayed, or the battery state display unit  56  may be entirely omitted. 
     At least any of the installation position of the battery terminal, the installation position of the battery lever, and the installation position of the battery state display unit  56  is variously changeable. For example, the battery lever and the battery state display unit  56  are each disposed on an identical surface so as not to be disposed on opposed surfaces. 
     The battery mounting portion  12  is formed at the rear portion of the main body housing  40  and has a flat plate portion expanding into a flat plate shape from front to back and from side to side. The flat plate portion of the battery mounting portion  12  has a depressed portion depressed downward from its top surface. The flat plate portion, which occupies the most part of the battery mounting portion  12 , is put to one side, which is the lower side, with respect to the above-described extended line of the machine axis M, and the battery mounting portion  12  has a front end portion having a staged surface N expanding from side to side and up and down (in further detail, obliquely upward to the front). 
     The battery mounting portion  12  includes rail portions  57  in the front-rear direction disposed right and left of the upper portion of the depressed portion, a plurality of terminals  58  projecting upward from a bottom surface of the depressed portion and extending in the front-rear direction, and a hollow  60  formed to be further depressed downward at the rear portion of the depressed portion. It should be noted that the depressed portion of the battery mounting portion  12  may be disposed at a part other than one surface of the flat plate portion, such as a top surface of a semicolumnar portion having a flat top surface and a curved lower surface. 
     The controller  61  is disposed below the terminals  58  in the battery mounting portion  12 . The controller  61  is held by front and rear ribs formed on an inner surface of the main body housing  40 . The respective terminals  58  and the controller  61  are electrically coupled to one another with a lead wire (not illustrated). 
     The battery  10  is slid forward from the rear of the battery mounting portion  12  in a state where the battery lever is on the rear side and the installation surface of the battery terminals are on the lower side, thus being mounted to the battery mounting portion  12 . 
     At this time, the rail portions  57  in the battery mounting portion  12  enter the rail guides  54  on the battery  10  to guide the battery  10 . It should be noted that rail portions may be disposed in the battery  10  and rail guides may be disposed in the battery mounting portion  12 , or rail portions and rail guides may be omitted. 
     The corresponding terminals  58  enter the respective groove portions on the battery  10 , and at the completion of mounting, the battery terminals inside the groove portions contact the terminals  58 . 
     Further, the battery claw  55  of the battery  10  enters the hollow  60  at the completion of mounting, and thus the battery  10  is reliably held in the battery mounting portion  12 . Additionally, when the user operates the battery lever to retreat the battery claw  55  from the hollow  60 , the battery  10  is removable from the battery mounting portion  12  by sliding to the rear. 
     In addition, a clearance is generated between the battery state display unit  56  on the front surface of the battery  10  and the staged surface N of the battery mounting portion  12 . Accordingly, the button on the battery state display unit  56  is easily operated and the display in the battery state display unit  56  is easily seen. Additionally, by gripping the front portion of the battery  10 , the battery  10  is easily removed from the battery mounting portion  12 . 
     The switch  62  is disposed on the handle portion  14 . 
     The switch  62  includes a switch main body  64  and a plunger  66  that projects downward from the switch main body  64  in a state whose amount of projection is changeable. 
     While an external force does not act, the plunger  66  is biased downward so as to be a predetermined maximum amount of projection, and when receiving the action, the plunger  66  moves upward to reduce the amount of projection. 
     The switch main body  64  changes a switching state according to the amount of projection of the plunger  66 . Here, when the amount of projection decreases from the maximum amount of projection by a predetermined amount or more and the plunger  66  moves upward from the predetermined switching position, the switch main body  64  (switch  62 ) switches on from off, and the switch  62  switches off from on in the reverse situation. 
     The switch  62  is electrically coupled to the controller  61  via a lead wire (not illustrated). 
     A paddle-shaped lever  68  is disposed below the switch  62 . 
     The lever  68  includes an arm portion  70  and a bus tab-shaped button portion  72  bulging downward. 
     Pins are stood on right and left of a rear end portion of the arm portion  70  so as to project outward in the right-left direction, and supporting the arm portion  70  by the main body housing  40  allows the lever  68  to rotate around the pins. Supporting the lower surface of the arm portion  70  to the inner surface of the main body housing  40  sets the lever  68  at a lowest position. The plunger  66  contacts the top surface of the rear portion of the button portion  72 . At the center of the button portion  72 , a rib  74  projecting upward is integrally formed. The button portion  72  is exposed in the lower portion of the main body housing  40 . 
     A lock arm  76  is disposed in front of the switch  62  and at the rear of the motor  16 . 
     The lock arm  76  is a member extending up and down. Pins are stood on right and left of the center of the lock arm  76  so as to project outward in the right-left direction. Entering the pins into the cylindrical bosses formed in the inner surface of the main body housing  40  allows the lock arm  76  to rotate around the pins. 
     On an upper end portion of the lock arm  76 , a slider  78  having a small protrusion shape is disposed to project upward. The slider  78  is exposed from a hole  80 , which is provided in an upper portion of the main body housing  40 . 
     The lock arm  76  has a lower end portion formed as an arrowhead-shaped portion  82  having an arrowhead shape. 
     When the user operates the slider  78  to be positioned forward, the lock arm  76  has an inclined posture downward to the rear, and a lower end portion of the arrowhead-shaped portion  82  is adjacent to the upper end portion of the rib  74  of the lever  68 . In this state, even when the button portion  72  of the lever  68  is pressed upward, the rib  74  abuts on the arrowhead-shaped portion  82  to hold back upward movements of the button portion  72  and the plunger  66  and to block the switching of the switch  62  to the on-state (off-lock state). A rib  84  in contact with the upper end portion of the arrowhead-shaped portion  82  in the off-lock state is disposed to project inward from the inner surface of the main body housing  40  on the upper side of the arrowhead-shaped portion  82 . The rib  84  holds back the upward movement of the arrowhead-shaped portion  82  to reliably block the upward movements of the button portion  72  and the plunger  66 . 
     Meanwhile, when the slider  78  is operated to be positioned rearward, the lock arm  76  has an approximately perpendicular posture and the arrowhead-shaped portion  82  is away from a space immediately above the rib  74  of the lever  68  and the rib  84 . Pressing the button portion  72  of the lever  68  in this state rotatably moves the lever  68  upward, the plunger  66  is pressed, and the switch  62  is switched to the on-state (off-lock released state). 
     Since only the switch  62  and the lock arm  76  are disposed inside the handle portion  14  and the motor  16  and the battery  10  are not disposed, the handle portion  14  can be formed to be further thinned and can be formed in a state further easily gripped by the user. 
     The motor  16  is a DC motor with brush and disposed in the front portion of the main body housing  40 . 
     The motor  16  includes a cylindrical motor case  90 , a motor shaft  92  in the front-rear direction, and a motor terminal  93 . The motor shaft  92  is disposed so as to penetrate the motor case  90  on its center axis and is rotatably driven around the center axis of itself. The motor terminal  93  projects rearward from the rear portion of the motor case  90 . The motor  16  is electrically coupled to the controller  61  via the motor terminal  93  with a lead wire (not illustrated). 
     The controller  61  controls driving of the motor  16  and controls the rotation of the motor shaft  92  in the motor  16 . When a current equal to or more than a predetermined threshold is detected, the controller  61  grasps the unintended lock state of the motor shaft  92  and stops the driving of the motor  16 . 
     Additionally, the motor  16  includes a fan  94  integrally mounted with the motor shaft  92 . The fan  94  is disposed inward a plurality of exhaust outlets  95 , which are circumferentially arranged in the motor case  90 . A plurality of exhaust outlets  96  are opened in parts positioned circumferentially outward the exhaust outlets  95  in the main body housing  40 . It should be noted that the fan  94  may be disposed separately from the motor  16  or may be omitted. 
     Meanwhile, a plurality of air inlets  98  are opened at the front and rear of the exhaust outlets  96  in the main body housing  40 . The respective air inlets  98  are disposed at the front and rear of the motor  16 . A pinion gear  99  is fixed to the distal end portion of the motor shaft  92  integrally with the motor shaft  92 . 
     The planetary gear mechanism  20  as a deceleration mechanism includes a ring-shaped internal gear  100  having internal teeth, a plurality of (three) planetary gears  102  having external teeth meshing with the internal gear  100 , pins  104  as shafts for the respective planetary gears  102 , and a carrier  106  holding all (three) pins  104 . 
     The internal gear  100  is unrotatably mounted into a rear diameter-expanded portion of the gear housing  42  via a gear retainer  108 . The gear retainer  108  extends from the inside of the rear diameter-expanded portion of the gear housing  42  to the inside of the front end portion of the main body housing  40 . 
     The planetary gears  102  are each disposed inward the internal gear  100 . 
     Each pin  104  has a columnar shape having its front-rear direction in the axis direction. 
     The respective planetary gears  102  are supported to the pins  104  in a state rotatable around the corresponding pin  104 . 
     The carrier  106  is a ring-shaped member having a small-diameter portion on a front side of a large-diameter portion. The large-diameter portion of the carrier  106  has holes supporting the front portions of the pins  104 . The planetary gears  102  are disposed on the rear portions of the respective pins  104 . The pins  104  and the planetary gears  102  are circumferentially disposed at regular intervals. The pinion gear  99  meshes with each planetary gear  102 . The front end portion of the pinion gear  99  enters the inside of the large-diameter portion of the carrier  106 . The carrier  106  is disposed rotatable around an axis of itself in the front-rear direction inside a front diameter-expanded portion of the gear housing  42 . 
     The spindle  22  as a reciprocating motion conversion mechanism is a columnar member running along the front-rear direction and includes a spindle main body portion  110 , a coupling portion  112 , and a columnar eccentric pin  116 . The coupling portion  112  is concentric with the spindle main body portion  110  and projects rearward from a rear surface of the spindle main body portion  110  in a state where the cross-sectional surface has a non-rotation symmetrical shape (oval shape) viewed at the center. The eccentric pin  116  projects forward from the front surface of the spindle main body portion  110  in an eccentric state from the center axis of the spindle main body portion  110 . 
     The spindle main body portion  110  is rotatably supported by front and rear bearings (needle bearings)  118  fixed inside the front portion of the gear housing  42  around the center axis in the front-rear direction. The center axis of the spindle main body portion  110 , the center axis of the planetary gear mechanism  20 , and the center axis of the motor shaft  92  match, becoming the machine axis M of the electric ratchet wrench  1 . 
     The coupling portion  112  enters an inner hole of the small-diameter portion of the carrier  106  having a cross-sectional shape identical to the coupling portion  112  and is coupled so as to integrally rotate with the carrier  106 . 
     The eccentric pin  116  is covered with a barrel-shaped sleeve  120  rotatable around the eccentric pin  116 . 
     A light  122  is disposed under the spindle  22 . 
     The light  122  is an LED and is entered in a depressed portion formed in a lower portion at the front end of the main body housing  40 . A wiring groove  124  to put a lead wire (not illustrated) of the light  122  is formed at the rear of the depressed portion in the main body housing  40 . The light  122  is electrically coupled to the controller  61  via the lead wire. 
     The light  122  is disposed to face a front lower side to illuminate around a lower side of the quadrilateral driving portion  34   c  of the socket adapter  34 . 
     The holder  26  is a ring-shaped member made of metal having an inner diameter slightly smaller than an inner diameter of the frame-shaped portion  52  of the gear housing  42  and disposed between an upper portion and a lower portion of the frame-shaped portion  52 . The holder  26  is rotatably disposed around a center axis in the up-down direction of its round hole. The holder  26  expands from front to back and from side to side, and the extended line of the machine axis M passes through a center between top and bottom surfaces (thickness) of the holder  26  and is perpendicular to the center axis in the up-down direction of its round hole. It should be noted that the machine axis M may be grasped including the holder  26  (output unit  32 ), and in this case, the machine axis M is from the front end portion of the holder  26  to the rear end portion of the motor shaft  92 . 
     The rear portion of the holder  26  reaches an inside of a front end portion of the handle-shaped portion  50  of the gear housing  42  and includes a vertical groove  126  having a semi-cylindrical surface shape having an up-down direction in the axis direction. 
     The sleeve  120  and the eccentric pin  116  enter an inside of the vertical groove  126 , and right and left of the sleeve  120  contact the vertical groove  126 . The rotation of the spindle  22  rotates the eccentric pin  116  and the sleeve  120  in the eccentric manner, and the movements of the portions in the right-left direction are transmitted to the holder  26  via the vertical groove  126  by pressing the vertical groove  126  with the sleeve  120 . Additionally, the movements of the portions in the up-down direction are performed in the vertical groove  126  and are not transmitted to the holder  26 . The movements in the up-down direction are smoothly performed by the rotation of the sleeve  120  around an eccentric pin  116 . Thus, the rotation of the spindle  22  is converted into reciprocating motions to the right and left, and the reciprocating motions are transmitted to the holder  26 . 
     A tubular socket  28  is entered into the hole of the holder  26  and the hole of the frame-shaped portion  52  of the gear housing  42  overlapping with the hole of the holder  26  via the one-way clutch mechanism  30 . 
     In an inner hole in the up-down direction of the socket  28 ,  12  nut corner contact grooves in which six corners of a hexagonal nut can be entered are formed extending up and down. 
     A direction switching lever  130  that switches the free direction and the lock direction of the one-way clutch mechanism  30  is disposed on the front upper portion of the socket  28 . It should be noted that the direction switching lever  130  may be disposed in the holder  26 . 
     The direction switching lever  130  includes a rod-shaped operating unit  132  exposed on the top surface of the socket  28 , a shaft portion  134  that projects downward from one end part of the operating unit  132 , and a cam portion  136  that projects from the lower end portion of the shaft portion  134  in a direction opposite to the operating unit  132 . The shaft portion  134  is disposed at the center on the upper portion of the socket  28 . Depressed portions  138  are formed on right and left on the top surface of the socket  28 , and a projecting portion  139  (see  FIG.  11   ) into which the depressed portion  138  can be entered is formed on the lower surface of the other end part of the operating unit  132 . It should be noted that the projecting portion  139  may be formed in the socket  28 , the depressed portion  138  may be formed in the direction switching lever  130 , or a lock portion and a locked portion according to another aspect may be formed. 
     When the operating unit  132  is disposed in a state where the projecting portion  139  enters one depressed portion  138 , by an action of the cam portion  136 , the one-way clutch mechanism  30  allows the socket  28  to rotate so as to relatively slide to the holder  26  in the predetermined direction (free direction) and holds back the rotation of the socket  28  to the holder  26  in the opposite direction (lock direction) to integrally rotate the socket  28  and the holder  26 . When the operating unit  132  is operated from this state to a state where the projecting portion  139  enters the other depressed portion  138 , the direction switching lever  130  rotates around the shaft portion  134 , the cam portion  136  rotates and changes its posture, and the one-way clutch mechanism  30  switches the direction between the above-described free direction and lock direction. It should be noted that even when the ratchet mechanism using the gear and the claw is not used, since the electric ratchet wrench  1  operates similarly to a wrench using the ratchet mechanism as long as the free direction and the lock direction, which is the direction opposite to the free direction, are present like the one-way clutch mechanism  30 , the electric ratchet wrench  1  may be referred to as a ratchet wrench. 
     The socket adapter  34  is mounted from the lower side of the socket  28 . It should be noted that the user may insert a nut or the like into the socket  28  in a state where the socket adapter  34  is not mounted and may fasten the nut or the like. 
     The following further describes the one-way clutch mechanism  30  in detail. 
       FIG.  5    is a top view of the electric ratchet wrench  1 ,  FIG.  6    is a perspective view of the one-way clutch mechanism  30  and the socket  28  and the socket adapter  34 ,  FIG.  7    and  FIG.  8    are exploded perspective views of  FIG.  6   , and the holder  26 , the spindle  22  and the gear housing  42 ,  FIG.  9    is a cross-sectional view taken along the line A-A of  FIG.  2   ,  FIG.  10    is an enlarged view of a front right portion of  FIG.  9   ,  FIG.  11    is a cross-sectional view taken along the line B-B of  FIG.  5   ,  FIG.  12    is a cross-sectional view taken along the line C-C of  FIG.  3   , and  FIG.  13    is an enlarged view of a front portion of  FIG.  12   . 
     The one-way clutch mechanism  30  includes a plurality of (eight) locking pins  140 , a retainer  142  and a ring  144  that hold the locking pins  140 , an upper C-shaped ring  146  and a lower C-shaped ring  148  disposed above and below the retainer  142  and the ring  144 , and the above-described direction switching lever  130 . 
     The locking pins  140  as locking members each have a columnar shape and has a size identical to one another. It should be noted that at least one locking pin  140  may have a hollow columnar shape or a cylindrical shape. 
     The retainer  142  is a crown-shaped member and includes a ring-shaped base portion  150  on the upper portion, eight projections  152  projecting downward from the base portion  150 , and springs  154  as elastic bodies mounted to the respective projections  152 . 
     Right and left pair of protrusions  156  projecting upward are formed on the top surface at the front portion of the base portion  150 . An installation part of the direction switching lever  130  in a front portion of a flange portion of the upper portion of the socket  28  is depressed upward to be thin compared with another part of the flange portion. The cam portion  136  of the direction switching lever  130  and the protrusions  156  on the base portion  150  of the retainer  142  are entered into the depressed portion. The pair of protrusions  156  are positioned right and left of the cam portion  136 . 
     Additionally, these projections  152  are disposed at regular intervals in a circumferential direction. A surface outside in a radial direction of each projection  152  serves as a part of a cylindrical surface. The projections  152  each have a length in the up-down direction similar to a length of each locking pin  140 . 
     The springs  154  include mounting portions wound outer sides in the radial direction at the centers of the projections  152  by half turn and leaf spring portions partially in contact with the projections  152  while warped into a “)” shape or a “(” shape on both sides of the mounting portions. It should be noted that the spring  154  may be an elastic block, may be mounted by a method other than winding, or may be individually disposed on each side of the projection  152 . 
     The ring  144  contacts the lower end portions of the respective projections  152  of the retainer  142  and is adjacent to the lower end portions of the respective locking pins  140 . 
     The upper C-shaped ring  146  is interposed between the lower surface of the flange portion of the upper portion of the socket  28  and the top surface of the base portion  150  to press the retainer  142  downward. 
     The lower C-shaped ring  148  is disposed on the lower side of the ring  144  and is mounted to the lower portion of the frame-shaped portion  52  of the gear housing  42  together with the ring  144 . 
     The locking pins  140  in a state of having the up-down direction in its axis direction are disposed one by one between the adjacent projections  152  and between the adjacent leaf spring portions of the springs  154 . Each locking pin  140  has an upper end portion adjacent to the base portion  150  of the retainer  142  and a lower end portion adjacent to the top surface of the ring  144 . Additionally, an inner surface of the hole of the holder  26  and an inner surface of the hole of the frame-shaped portion  52  of the gear housing  42  are positioned radially outward of the base portion  150  in the respective locking pins  140 . These inner surfaces are cylindrical surfaces. Meanwhile, the outer surface at the center of the socket  28  is positioned radially inward of the base portion  150  in the respective locking pins  140 . The outer surface at the center of the socket  28  has a shape equivalent to a side surface of a regular octagonal pillar. In more detail, the outer surface is a side surface of a chamfered regular octagonal pillar, that is, a side surface of a hexadecagonal pillar having a shape close to the regular octagonal pillar. Each side surface has a length in the up-down direction similar to a length of each locking pin  140 . Additionally, each side surface has a width in a circumferential direction around twice to three times of a diameter of each locking pin  140 . 
     The pair of protrusions  156  are positioned on the upper side of the pair of projections  152  between which the locking pin  140  on the frontmost is interposed, and the cam portion  136  of the direction switching lever  130  is positioned above the locking pin  140  on the frontmost. 
     In a case where the operating unit  132  of the direction switching lever  130  is engaged with the right depressed portion  138  (a case illustrated in each drawing), as illustrated in  FIG.  13 A , the cam portion  136  is at a rotation position (phase) where the most part of the cam portion  136  is positioned left viewed from a rotational center T matching with the center of the shaft portion  134  to dispose the retainer  142  at a phase illustrated in  FIG.  10 A  via the protrusions  156 . The respective locking pins  140  are disposed at positions outward of one surface corresponding to the side surface of the socket  28  having the regular octagonal pillar and approaching a clockwise direction (a direction of an arrow L 1 ) in  FIG.  10 A  viewed from a center line U in the up-down direction passing through a circumferential center of the one surface with the projections  152  of the retainer  142 . 
     In this case, the spaces in which the respective locking pins  140  are disposed include large interval portions and small interval portions. The large interval portion is interposed between a virtual first surface, which is formed by radially extending the center line U on the outer surface of the socket  28  to the inner surface of the hole of the holder  26  and the inner surface of the hole of the frame-shaped portion  52 , and a virtual second surface opposed to the first surface separated around a radius of the locking pin  140 . The small interval portion is adjacent to the second surface of the large interval portion in the direction of the arrow L 1 . A maximum distance Ka in a radial direction in the large interval portion is a dimension of a side in the radial direction of the first surface and is larger than a smallest distance Kb in the radial direction in the small interval portion. The distance Ka is equal to or more than the diameter of the locking pin  140 , and the distance Kb is less than the diameter of the locking pin  140 . 
     In respective spaces in this case, the small interval portions are all disposed in the direction of the arrow L 1  viewed from the large interval portions and are similar to one another in the rotation direction (circumferential direction) of the socket  28 . 
     In this state, the rotation of the holder  26  in the direction of the arrow L 1  (lock direction) causes the respective locking pins  140  to approach the small interval portion sides from the state illustrated in the drawing in association with the rotation of the holder  26  by, for example, friction force and inertia force from the holder  26 , and the locking pins  140  are in line contact with the respective holder  26  and socket  28  and are meshed between the portions, and the socket  28  locks the holder  26  with the meshed locking pins  140  to rotate integrally with the holder  26 . The meshing of the locking pins  140  is assisted by the biasing action caused by pressing by the leaf spring portions of the springs  154  disposed on the side in the opposite direction to the arrow L 1 . It should be noted that the leaf spring portions of the springs  154  disposed on the side of the arrow L 1  direction are disposed so as to hardly act to the meshed locking pins  140  and therefore do not press the meshed locking pins  140 . 
     Meanwhile, the rotation of the holder  26  in the direction opposite to the arrow L 1  (free direction) causes the respective locking pins  140  to approach the large interval portion sides in association with the rotation of the holder  26  as illustrated in the drawing to be released from the meshed state, the lock of the holder  26  by the socket  28  is released, the relative rotation of the socket  28  to the holder  26  is allowed, and the socket  28  idles to the holder  26 . 
     Alternatively, in a case where the operating unit  132  of the direction switching lever  130  is moved from a position engaged with the right depressed portion  138  to a position engaged with the left depressed portion  138 , as illustrated in  FIG.  13 B , the cam portion  136  is rotated to move to a phase where the most part of the cam portion  136  is positioned right viewed from the rotational center T. Then, the retainer  142  is rotated to move such that a distance becomes around one time to 1.5 times of the diameter of each locking pin  140  (around a half of the width in the circumferential direction of each side surface of the socket  28 ) to cause the retainer  142  to reach the phase illustrated in  FIG.  10 B . The respective locking pins  140  are disposed at positions approaching an anticlockwise direction (a direction of an arrow L 2 ) in  FIG.  10 B  viewed from the center line U on one side surface of the socket  28  with the retainer  142 . 
     In this case, the spaces in which the respective locking pins  140  are disposed include large interval portions and small interval portions. The large interval portion is interposed between a virtual third surface, which is formed by radially extending the center line U on the outer surface of the socket  28  to the inner surface of the hole of the holder  26  and the inner surface of the hole of the frame-shaped portion  52 , and a virtual fourth surface opposed to the third surface separated around a radius of the locking pin  140 . The small interval portion is adjacent to the fourth surface of the large interval portion in the direction of the arrow L 2 . A maximum distance Kc in a radial direction in the large interval portion is a dimension of a side in the radial direction of the third surface and is larger than a smallest distance Kd in the radial direction in the small interval portion. The distance Kc is equal to or more than the diameter of the locking pin  140 , and the distance Kd is less than the diameter of the locking pin  140 . 
     The distance Kc in this case is approximately identical to the above-described distance Ka, and the large interval portion in this case and the above-described large interval portion can be grasped as one common large interval portion. 
     Additionally, since the center of the socket  28  has the regular octagonal pillar shape and the inner surface of the hole of the holder  26  is the cylindrical surface, the small interval portion in this case is symmetrical to the above-described small interval portion with respect to the center line U as a symmetrical axis, and the distance Kd and the above-described distance Kb are approximately equal. 
     In respective spaces in this case, the small interval portions are all disposed in the direction of the arrow L 2  viewed from the large interval portions and are similar to one another in the rotation direction (circumferential direction) of the socket  28 . 
     In this state, the rotation of the holder  26  in the direction of the arrow L 2  (lock direction) causes the respective locking pins  140  to approach the small interval portion sides from the state illustrated in the drawing, and the locking pins  140  are in line contact with the respective holder  26  and socket  28  and are meshed between the portions, and the socket  28  locks the holder  26  to rotate integrally with the holder  26 . The meshing of the locking pins  140  is assisted by the bias by the leaf spring portions of the springs  154  disposed on the side in the opposite direction to the arrow L 2 . 
     Meanwhile, the rotation of the holder  26  in the direction opposite to the arrow L 2  (free direction) causes the respective locking pins  140  to approach the large interval portion sides as illustrated in the drawing to be released from the meshed state, the lock of the holder  26  by the socket  28  is released, and the socket  28  idles to the holder  26 . 
     The arrows L 1  and L 2 , which correspond to the directions that the socket  28  locks the holder  26 , face the opposite directions to one another. The user changes the position of the operating unit  132  of the direction switching lever  130  to ensure switching the lock direction. The direction of the arrow L 2  is in the clockwise direction viewed from above and may be referred to as a forward direction, and the direction of the arrow L 1  is in the anticlockwise direction viewed from the above and may be referred to as a reverse direction. 
     It should be noted that the numbers of locking pins and spaces are not limited to eight but may be one or more to seven or less or may be nine or more. A part of the plurality of spaces and locking pins may have different shapes and sizes from the other spaces and locking pins, that is, the number of types of the spaces and the locking pins may be plural. In the spaces, the small interval portion may be disposed only on one side of the large interval portion. As long as the space including the large interval portion and the small interval portion is formed, the outer surface of the socket  28  may have a side surface shape of another regular polygonal prism or may have a side surface shape of a polygonal prism, such as an octagonal pillar not a regular octagonal pillar. Additionally, the outer surface of the socket  28  may be configured to have a cylindrical surface shape (columnar surface shape), the inner surface of the hole of the holder  26  may be configured to have a side surface shape of a regular polygonal prism or a side surface shape of a polygonal prism not a regular polygonal prism, or both of the outer surface of the socket  28  and the inner surface of the hole of the holder  26  may be configured to have a side surface shape of a polygonal prism. Alternatively, for example, a curved surface, such as an elliptic cylindrical surface, and a combination of a curved surface and a side surface of a polygonal prism may be used. 
     The operation example of the electric ratchet wrench  1  will be described. 
     The user mounts the battery  10  preliminarily charged with a charger to the battery mounting portion  12  by sliding forward. 
     Then, when the user grips the handle portion  14 , slides the slider  78  on the lock arm  76  rearward, and presses the button portion  72  on the lever  68  upward, the plunger  66  is pressed upward and the switch  62  switches to on. The battery  10  feeds power to the light  122  and the motor  16  via the controller  61 , the light  122  lights up to illuminate below the socket  28 , and the motor shaft  92  of the motor  16  is driven by the control by the controller  61 . It should be noted that the switching of the switch  62  and the control by the controller  61  may be adjusted such that switching timings of the light  122  and the motor  16  become different, such as the light  122  turning on at the beginning of a rising of the plunger  66  (beginning of pressing the button portion  72 ) and the motor  16  tuning on at further rising (pressing the button portion  72 ). 
     The rotation of the motor shaft  92  rotates the fan  94  to exhaust air from the exhaust outlets  95  and  96  and wind from the air inlets  98  to the exhaust outlets  95  and  96  is formed. The wind cools an internal mechanism of the electric ratchet wrench  1 , such as the motor  16 . 
     Further, a rotation force of the motor shaft  92  is decelerated by the planetary gear mechanism  20  and transmitted to the spindle  22 . The rotation force of the spindle  22  is converted into the right and left reciprocating rotation motion forces of the holder  26 , and the converted forces are appropriately transmitted to the socket  28  via the one-way clutch mechanism  30 . 
     The action of the one-way clutch mechanism  30  applies the reciprocating rotation motion force in the lock direction to the socket  28  and the socket adapter  34  and the exchange socket mounted to the socket  28  by the meshing of the respective locking pins  140  in the small interval portions. The reciprocating rotation motion force in the free direction is not applied by releasing the meshing by the movement of the respective locking pins  140  to the large interval portions. Accordingly, the socket  28  and the exchange socket give a torque to the fitted nut or the like only in the lock direction and do not give a torque in the opposite direction. Therefore, the fastening of the nut or the like is progressed intermittently in the lock direction at each reciprocation motion or the removal is similarly progressed. 
     In a case where an electric power of the battery  10  becomes insufficient, the user removes the battery  10  from the battery mounting portion  12  by sliding rearward, sets the battery  10  to the charger for charging, and mounts the charged battery  10  or another battery  10  to the battery mounting portion  12 . 
     The electric ratchet wrench  1  according to the first embodiment described above includes the electric motor  16 , the holder  26 , and the spindle  22 . The holder  26  rotatably holds the socket  28  via the one-way clutch mechanism  30 . The spindle  22  is configured to convert the driving force from the motor  16  into the reciprocating rotation motion of the holder  26 . The space is provided between the socket  28  and the holder  26 . The space includes the large interval portion and the small interval portion. The small interval portion is adjacent to the large interval portion in the rotation direction (lock direction) of the socket  28 . The small interval portion has the distance Kb or Kd smaller than that (distance Ka or Kc) of the large interval portion. The one-way clutch mechanism  30  includes the columnar locking pin  140  disposed in the space. The locking pin  140  has the diameter having the size equal to or less than the distance Ka or Kc of the large interval portion and exceeding the distance Kb or Kd of the small interval portion. 
     Accordingly, the rotation of the holder  26  in the direction from the large interval portions to the small interval portions (lock direction) causes the locking pins  140  to enter the small interval portions having the distances Kb and Kd less than the diameter of the locking pin  140  and to be meshed between the holder  26  and the socket  28 , and the socket  28  integrally rotates with the holder  26 . Meanwhile, the rotation of the holder  26  in the direction from the small interval portions to the large interval portions (free direction) causes the locking pins  140  to enter the large interval portions having the distances Ka and Kc equal to or more than the diameter of the locking pin  140 , the meshing of the locking pins  140  between the holder  26  and the socket  28  is released, and the socket  28  idles to the holder  26 . 
     The one-way clutch mechanism  30  includes the large interval portions and the small interval portions, and can be installed only by ensuring the spaces where the locking pins  140  are entered, which results in being compact. Further, since the one-way clutch mechanism  30  performs locking by meshing the locking pins  140 , sufficient locking strength can be obtained without increasing the sizes of the locking pins  140  so much. Therefore, the electric ratchet wrench  1  having both compactability and a lock performance is provided. 
     Additionally, the small interval portions are disposed on both sides in the circumferential direction of the large interval portions. The retainer  142  that can change the spaces for one small interval portion and large interval portion (see  FIG.  10 A ) to spaces for another small interval portion and large interval portion (see  FIG.  10 B ) is disposed between the socket  28  and the holder  26 . Accordingly, the retainer  142  can switch the direction that the locking pins  140  are meshed from the large interval portions to the small interval portions. Thus, the lock direction can be easily and reliably switched. 
     Further, the retainer  142  includes the pair of protrusions  156 , and the direction switching lever  130  including the cam portion  136  in contact with the protrusions  156  is disposed on the socket  28 . Accordingly, the lock direction can be further easily and reliably switched. 
     Further, the springs  154  that bias the locking pins  140  in the direction where the small interval portions are disposed viewed from the large interval portions are disposed in the retainer  142 . Accordingly, the movement of the locking pins  140  to the small interval portions is assisted, and the socket  28  is further smoothly locked with the locking pins  140 , thus further improving the lock performance. 
     In addition, the plurality of spaces are disposed in the state where the arrangements of the small interval portions relative to the large interval portions in the rotation direction are similar to one another, and the locking pins  140  are disposed between the respective spaces. Accordingly, the plurality of locking pins  140  mesh in the lock direction, and thus the electric ratchet wrench  1  with the further improved locking strength is provided. 
     Additionally, the socket  28  has the outer surface formed into the side surface shape of the regular octagonal pillar, and the holder  26  has the inner surface formed into the cylindrical surface shape. Accordingly, the spaces including the large interval portions and the small interval portions are simply formed, and the plurality of spaces including the small interval portions on both sides of the large interval portions are simply formed. 
     It should be noted that the above-described electric ratchet wrench  1  as one example of the straight type electric power tool includes the motor  16 , the power transmission unit  24 , the battery  10 , and the battery mounting portion  12 . The power transmission unit  24  transmits the driving force from the motor  16  to the output unit  32  on the front side. The battery  10  drives the motor  16 . The battery  10  is mounted to the battery mounting portion  12 . The motor  16 , the power transmission unit  24 , and the output unit  32  are linearly arranged in the front-rear direction. The output axis O of the output unit  32  is directed in the up-down direction intersecting with the front-rear direction and extends downward. The battery mounting portion  12  is disposed at the rear of the power transmission unit  24  and the motor  16 . The battery  10  is slidingly mounted to the upper side (the side opposite to the side from which the output axis O extends) of the battery mounting portion  12 . Thus, the battery  10  is easily replaced and the electric ratchet wrench  1  excellent in operability regarding the battery  10  is provided. 
     Additionally, the battery  10  is mounted so as to be oriented in the front-rear direction. Accordingly, the mounted battery  10  is oriented in the same direction as the direction in which the motor  16 , the power transmission unit  24 , and the output unit  32  are arranged. The battery  10  is mounted with a small protrusion from the motor  16 , the power transmission unit  24 , and the output unit  32 , thereby further facilitating the operation of the electric ratchet wrench  1 . 
     Further, the motor  16 , the power transmission unit  24 , and the output unit  32  are arranged around the machine axis M, and the battery mounting portion  12  is put to one side, which is the lower side, with respect to the machine axis M. Thus, compared with a case where the battery mounting portion  12  is not put to one side, the battery  10  is mounted more closer to the machine axis M. Accordingly, the battery  10  is mounted with a further small protrusion and its center of gravity is further close to the machine axis M, thus improving the operability of the electric ratchet wrench  1 . 
     It should be noted that the first embodiment of the invention is not limited to the above-described embodiments and modification examples but, for example, further includes the following modification examples appropriately. 
     The battery mounting portion may be formed to face downward such that the terminal projects downward from the lower surface and further may be put to one side, which is the upper side, with respect to the machine axis or its extended line. 
     A plurality of batteries may be mounted. In this case, when all batteries are disposed to be oriented in the front-rear direction, the batteries are each mounted with a small protrusion. For example, the respective batteries oriented in the front-rear direction may be mounted to the top and bottom of the rear portion of the main body housing formed so as to expand from front to back and from side to side including the machine axis or its extended line. 
     The batteries may be mounted to the right and left of the rear portion of the main body housing. Additionally, the battery may be mounted in an oblique direction having an angle with respect to a direction (front-rear direction) in which the motor, the planetary gear mechanism, and the spindle are arranged. Further, the battery mounting portion may be rotatable to another part, such as the main body housing, such that a posture of the mounted battery (for example, from a horizontal posture to a vertical posture) relative to the front-rear direction becomes variable. 
     Regarding the planetary gear mechanism, instead of the insertion of the pin to the carrier, for example, a shaft-shaped protrusion may be formed integrally with the carrier. 
     The planetary gear mechanism may be changed to another deceleration mechanism, may be configured as a mechanism transmitting power without deceleration, or may be omitted. 
     One or two or more of intermediate shafts may be interposed between the motor shaft and the holder. 
     As the battery, any lithium-ion battery, such as 14.4 V, 18 V (maximum 20 V), 18 V, 25.2 V, 28 V, and 36 V may be used, a lithium-ion battery having a voltage less than 10.8 V or exceeding 36 V may be used, or a battery of another type may be used. The battery may be rechargeable in a state being mounted to the battery mounting portion. 
     Instead of the battery mounting portion and the battery, a power supply cord coupled to a commercial power supply may be disposed and an AC motor is used as the motor to configure an AC electric ratchet wrench. Alternatively, the motor may be configured as a motor driven by air to configure an air ratchet wrench as one example of an air tool. With the air ratchet wrench, the spindle may be directly rotated by air. The numbers of various members and parts, and arrangements, materials, sizes, configurations, and the like of various members and parts may be appropriately changed, such as increase and decrease in the number of sections of the housing, the number of installed planetary gears, the number of stages of the planetary gear mechanism, the number of exhaust outlets, and the number of bearings. 
     Further, the invention is applicable to, for example, another straight type electric power tool, such as a multi tool and a multi cutter, a straight type electric power tool coupled to a commercial power supply, or a straight type gardening tool, such as a trimmer for gardening. 
     Second Embodiment 
     An electric ratchet wrench according to the second embodiment of the invention is configured similarly to the first embodiment excluding the locking pins and the retainer of the one-way clutch mechanism and the socket. Same reference numerals are given to the members and the parts configured similarly to those of the first embodiment and descriptions thereof are appropriately omitted. 
       FIG.  14    is a drawing according to the second embodiment similar to  FIG.  10   . 
     An outer surface at the center of a socket  228  of the second embodiment has a shape equivalent to a side surface of a regular nonagonal pillar. 
     Locking pins  240  of a one-way clutch mechanism  230  of the second embodiment are disposed by nine. Projections  252  of a retainer  242  of the second embodiment are disposed by nine, and nine spaces are disposed between the projections  252  where the locking pins  240  are disposed similarly to the first embodiment. 
     The respective locking pins  240  as locking members are pillar-shaped members having the axis direction in the up-down direction. A cross-sectional surface of each locking pin  240  perpendicular to the axis direction has an elliptical shape. In more detail, the cross-sectional surface has a shape enclosed by a pair of parallel straight lines facing one another and a pair of arcs convexed outward coupled to any one of end portions of the straight lines. Accordingly, the locking pins  240  each include a pair of planar portions  240   a  parallel in the axis direction and a pair of cylindrical surface-shaped bulge portions  240   b.    
     In each locking pin  240 , a virtual plane parallel to both planar portions  240   a  at equal distances includes a center axis at the center of the socket  228 . Each locking pin  240  faces a radial direction as a direction perpendicular to the rotation direction of the socket  228  (a direction perpendicular to the retainer  242  and the annular-shaped part of the holder  26 ). Between the pair of bulge portions  240   b  (distance J 1 ) has a size equal to or less than the distances Ka and Kc of the large interval portions and exceeding the distances Kb and Kd of the small interval portions in the spaces in which the respective locking pins  240  are disposed. 
     Each locking pin  240  has a locking pin side depressed portion  240   c , which depresses inward, at the center in the up-down direction in each planar portion  240   a.    
     Additionally, projection part side depressed portions  252   a , which depress inward, are disposed on both sides of the projection  252  of the retainer  242  in a circumferential direction and parts opposed to the locking pin side depressed portions  240   c.    
     Springs  254  instead of the springs  154  of the first embodiment are bridged between the locking pin side depressed portions  240   c  and the projection part side depressed portions  252   a  facing one another. 
     The electric ratchet wrench of the second embodiment operates similarly to the electric ratchet wrench  1  of the first embodiment. 
     Especially, with an action of the one-way clutch mechanism  230 , the reciprocating rotation motion force in the lock direction is applied to the socket  228  and the socket adapter  34  and the exchange socket mounted to the socket  228  by the pair of bulge portions  240   b  (distance J 1 ) of the respective locking pins  240  being meshed to the small interval portions in line contact. The reciprocating rotation motion force in the free direction is not applied by releasing the meshing by the movement of the respective locking pins  240  to the large interval portions. 
     The meshing of the respective locking pins  240  are assisted by the biasing action by the springs  254  disposed on both sides of the projection  252  in the circumferential direction. 
     The electric ratchet wrench of the second embodiment includes the electric motor  16 , the holder  26 , and the spindle  22 . The holder  26  rotatably holds the socket  228  via the one-way clutch mechanism  230 . The spindle  22  is configured to convert the driving force from the motor  16  into the reciprocating rotation motion of the holder  26 . The space is provided between the socket  228  and the holder  26 . The space includes the large interval portion and the small interval portion. The small interval portion is adjacent to the large interval portion in the rotation direction (lock direction) of the socket  228 . The small interval portion has the distance Kb or Kd smaller than that (distance Ka or Kc) of the large interval portion. The one-way clutch mechanism  230  includes the locking pin  240  disposed in the space. The locking pin  240  has the size equal to or less than the distance Ka or Kc of the large interval portion and exceeding the distance Kb or Kd of the small interval portion (distance J 1 ). 
     Accordingly, the rotation of the holder  26  in the direction from the large interval portions to the small interval portions (lock direction) causes the locking pins  240  to enter the small interval portions having the distances Kb and Kd less than the size between the bulge portions  240   b  (distance J 1 ) and to be meshed between the holder  26  and the socket  228 , and the socket  228  integrally rotates with the holder  26 . Meanwhile, the rotation of the holder  26  in the direction from the small interval portions to the large interval portions (free direction) causes the locking pins  240  to enter the large interval portions having the distances Ka and Kc equal to or more than the size between the bulge portions  240   b  (distance J 1 ), the meshing of the locking pins  240  between the holder  26  and the socket  228  is released, and the socket  228  idles to the holder  26 . 
     The one-way clutch mechanism  230  includes the large interval portions and the small interval portions, and can be installed only by ensuring the spaces where the locking pins  240  are entered, which results in being compact. Further, since the one-way clutch mechanism  230  performs locking by meshing the locking pins  240 , sufficient locking strength can be obtained without increasing the sizes of the locking pins  240  so much. Therefore, the electric ratchet wrench having both compactability and a lock performance is provided. 
     Additionally, the locking pin  240  includes the pair of planar portions  240   a , which are arranged in the direction that the small interval portions are disposed viewed from the large interval portions (circumferential direction), and the pair of bulge portions  240   b , which couple between the end portions of the planar portions  240   a . The size between the pair of bulge portions  240   b  (distance J 1 ) is equal to or less than the distances Ka and Kc of the large interval portions and exceeding the distances Kb and Kd of the small interval portions. Accordingly, while the locking with the sufficient strength is obtained with the bulge portions  240   b , the planar portions  240   a  make the locking pins  240  and eventually the holder  26  and the socket  228  compact. Additionally, disposing the locking pin side depressed portions  240   c  in the planar portions  240   a  prevents each locking pin  240  from rolling in the space and the springs  254  reliably enter the locking pin side depressed portions  240   c . Even if the spring  254 , which assists the meshing of each locking pin  240 , has a shape other than the leaf spring or a comparatively large size, the spring  254  is reliably held. 
     Further, the pair of planar portions  240   a  are parallel to one another. Thus, the locking pin  240  or the like is downsized, and the holding portion where the spring  254  is reliably held is simply installed. 
     The electric ratchet wrench of the second embodiment appropriately has the modification examples similar to those of the first embodiment. 
     Additionally, at least one of the bulge portions  240   b  needs not to have the cylindrical surface. 
     The number of locking pins  240  may be a number other than nine. The socket  228  may have an octagonal pillar shape or less or may have a decagonal pillar shape or more, or may have another shape. 
     The locking pins  140  and  240  of the first and the second embodiments may be mixed. 
     Third Embodiment 
     An electric ratchet wrench according to the third embodiment of the invention is configured similarly to the second embodiment excluding the locking pins and the retainer of the one-way clutch mechanism. Same reference numerals are given to the members and the parts configured similarly to those of the second embodiment and descriptions thereof are appropriately omitted. 
       FIG.  15    is a drawing according to the third embodiment similar to  FIG.  10   . 
     In a projection  352  of a retainer  342  in a one-way clutch mechanism  330  of the third embodiment, an arc radially outside in its cross-sectional surface has a shape longer than an inner arc and surfaces of both end portions in the circumferential direction have a posture of expanding from a radial direction toward radially inside. In surfaces of both end portions in the circumferential direction of the projection  352 , projection portion side depressed portions  352   a  perpendicular to the projection  352  are disposed. 
     The pair of planar portions  340   a  in nine locking pins  340  have a posture of expanding toward the socket  228 . The planar portion  340   a  faces the surface of the end portion in the circumferential direction of the projection  352  parallel to one another. The planar portions  340   a  each include a locking pin side depressed portion  340   c  perpendicular to the planar portion  340   a . The locking pin side depressed portion  340   c  faces the projection portion side depressed portion  352   a . The size (distance J 2 ) between bulge portions  340   b , which couple between the end portions of the respective planar portions  340   a , is equal to or less than the distances Ka and Kc of the large interval portions and exceeding the distances Kb and Kd of the small interval portions in the spaces in which the locking pins  340  are disposed. 
     The spring  254  similar to those of the second embodiment is bridged between the locking pin side depressed portion  340   c  and the projection portion side depressed portion  352   a , which faces one another, so as to be oriented in the same directions of the locking pin side depressed portion  340   c  and the projection portion side depressed portion  352   a.    
     The electric ratchet wrench of the third embodiment operates similarly to the electric ratchet wrench of the second embodiment. 
     Especially, with the action of the one-way clutch mechanism  330 , the reciprocating rotation motion force in the lock direction is applied to the socket  228  and the socket adapter  34  and the exchange socket mounted to the socket  228  by the pair of bulge portions  340   b  (distance J 2 ) of the respective locking pins  340  being meshed to the small interval portions in line contact. The reciprocating rotation motion force in the free direction is not applied by releasing the meshing by the movement of the respective locking pins  340  to the large interval portions. 
     The meshing of the respective locking pins  340  are assisted by the biasing action by the springs  254  disposed on both sides of the projection  352  in the circumferential direction. 
     The one-way clutch mechanism  330  of the electric ratchet wrench according to the third embodiment includes the locking pin  340  disposed in the space. The locking pin  340  has the size equal to or less than the distance Ka or Kc of the large interval portion and exceeding the distance Kb or Kd of the small interval portion (distance J 2 ). 
     Accordingly, the rotation of the holder  26  in the direction from the large interval portions to the small interval portions (lock direction) causes the locking pins  340  to enter the small interval portions having the distances Kb and Kd less than the size between the bulge portions  340   b  (distance J 2 ) and to be meshed between the holder  26  and the socket  228 , and the socket  228  integrally rotates with the holder  26 . Meanwhile, the rotation of the holder  26  in the direction from the small interval portions to the large interval portions (free direction) causes the locking pins  340  to enter the large interval portions having the distances Ka and Kc equal to or more than the size between the bulge portions  340   b  (distance J 2 ), the meshing of the locking pins  340  between the holder  26  and the socket  228  is released, and the socket  228  idles to the holder  26 . 
     The one-way clutch mechanism  330  includes the large interval portions and the small interval portions, and can be installed only by ensuring the spaces where the locking pins  340  are entered, which results in being compact. Further, since the one-way clutch mechanism  330  performs locking by meshing the locking pins  340 , sufficient locking strength can be obtained without increasing the sizes of the locking pins  340  so much. Therefore, the electric ratchet wrench having both compactability and a lock performance is provided. 
     Additionally, the locking pin  340  includes the pair of planar portions  340   a , which are arranged in the direction that the small interval portions are disposed viewed from the large interval portions (circumferential direction), and the pair of bulge portions  340   b , which couple between the end portions of the planar portions  340   a . The size between the pair of bulge portions  340   b  (distance J 2 ) is equal to or less than the distances Ka and Kc of the large interval portions and exceeding the distances Kb and Kd of the small interval portions. Accordingly, while the locking with the sufficient strength is obtained with the bulge portions  340   b , the planar portions  340   a  make the locking pins  340  and eventually the holder  26  and the socket  228  compact. Additionally, disposing the locking pin side depressed portions  340   c  in the planar portions  340   a  prevents each locking pin  340  from rolling in the space and the springs  254  reliably enter the locking pin side depressed portions  340   c . Even if the spring  254 , which assists the meshing of each locking pin  340 , has a shape other than the leaf spring or a comparatively large size, the spring  254  is reliably held. 
     Further, the pair of planar portions  340   a  have a posture of expanding toward the socket  228 . Accordingly, the locking pin  340  is each disposed in a state so as to increase in size in the circumferential direction as heading radially inward between the projections  352  of the retainer  342 . Accordingly, when the holder  26 , the socket  228 , and the one-way clutch mechanism  330  are manufactured, the respective locking pins  340  are less likely to come off outside. 
     The electric ratchet wrench of the third embodiment appropriately has the modification examples similar to those of the second embodiment. 
     Additionally, at least one planar portion  340   a  may be configured as a curved surface and have a posture of expanding toward the socket  228 . 
     At least any of two kinds of the locking pins  140 ,  240 , and  340  according to the first to the third embodiment may be mixed. 
     Fourth Embodiment 
     An electric ratchet wrench according to the fourth embodiment of the invention is configured similarly to the first embodiment excluding the locking pins and the retainer of the one-way clutch mechanism. Same reference numerals are given to the members and the parts configured similarly to those of the first embodiment and descriptions thereof are appropriately omitted. 
       FIGS.  16 A and  16 B  are exploded perspective views of a retainer and balls of the electric ratchet wrench according to the fourth embodiment when viewed from a left upper side ( FIG.  16 A ) and a left lower side ( FIG.  16 B ). 
     In a retainer  442  in the one-way clutch mechanism of the fourth embodiment, the projections  152  of the first embodiment are disposed by nine and lower end portions of the respective projections  152  are coupled into a ring shape (the ring  144  is integrated with the retainer  142 .) That is, the retainer  442  is a cylindrical member having nine windows  442   a  circumferentially arranged and each extending up and down. Thus, since the retainer  442  is configured by coupling the lower end portions of the respective projections  152  into the ring shape, the strength is further excellent. 
     Excluding that leaf spring portions are not warped and mounting portions of leaf springs are routed to an inside of the retainer  442 , springs  454  configured similarly to the springs  154  of the first embodiment are disposed on both sides of the windows  442   a  in the circumferential direction. 
     Since the nine windows  442   a  are disposed, the nonagonal pillar-shaped socket  228  according to the second embodiment is used in the fourth embodiment. 
     Similar to the space between the projections  152  of the retainer  142  of the first embodiment, the respective windows  442   a  form spaces including the large interval portions (distances Ka and Kc) and the small interval portions (distances Kb and Kd) between the socket  228  and the holder  26 . 
     In each window  442   a , three balls  440  (locking members) made of iron are disposed to be arranged up to down. 
     Each ball  440  has a diameter with a size (distance J 3 ) equal to or less than the distance Ka or Kc of the large interval portion and exceeding the distance Kb or Kd of the small interval portion. 
     The balls  440  are each configured to contact the spring  454 . 
     The electric ratchet wrench of the fourth embodiment operates similarly to the electric ratchet wrench  1  of the first embodiment. 
     Especially, with an action of the one-way clutch mechanism of the fourth embodiment, the reciprocating rotation motion force in the lock direction is applied to the socket  228  and the socket adapter  34  and the exchange socket mounted to the socket  228  by meshing (point contact) of each ball  440  (of which diameter is distance J 3 ) to the small interval portion. The reciprocating rotation motion force in the free direction is not applied by releasing the meshing by the movement of the respective balls  440  to the large interval portions. 
     The meshing of the respective balls  440  is assisted by a biasing action of the springs  454  disposed on both sides of the windows  442   a  in the circumferential direction. 
     The one-way clutch mechanism of the electric ratchet wrench of the fourth embodiment includes the balls  440  disposed in the windows  442   a  and having the size (distance J 3 ) equal to or less than the distances Ka and Kc of the large interval portions and exceeding the distances Kb and Kd of the small interval portions. 
     Accordingly, the rotation of the holder  26  in the direction from the large interval portions to the small interval portions (lock direction) causes the balls  440  to enter the small interval portions having the distances Kb and Kd less than the diameter of the balls  440  (distance J 3 ) and to be meshed between the holder  26  and the socket  228 , and the socket  228  integrally rotates with the holder  26 . Meanwhile, the rotation of the holder  26  in the direction from the small interval portions to the large interval portions (free direction) causes the balls  440  to enter the large interval portions having the distances Ka and Kc equal to or more than the size of the diameter of the ball  440  (distance J 3 ), the meshing of the balls  440  between the holder  26  and the socket  228  is released, and the socket  228  idles to the holder  26 . 
     The one-way clutch mechanism of the fourth embodiment includes the large interval portion and the small interval portion, and can be installed only by ensuring the spaces where the balls  440  are entered, which results in being compact. Further, since the one-way clutch mechanism of the fourth embodiment performs locking by meshing the balls  440 , sufficient locking strength can be obtained without increasing the sizes of the balls  440  so much. 
     Therefore, the electric ratchet wrench having both compactability and a lock performance is provided. 
     Additionally, since the locking members are the balls  440 , the locking member can be achieved at a low cost. 
     The electric ratchet wrench according to the fourth embodiment appropriately has modification examples similar to those of the first to third embodiments. 
     Additionally, the balls  440  may be disposed in each window  442   a  by two or less or may be disposed by four or more, or the different numbers of the balls  440  may be disposed in each of the windows  442   a.    
     A locking member formed by coupling the plurality of balls  440  into a rod shape may be employed. 
     The number of windows  442   a  may be eight or less or may be 10 or more. Arrangement of the windows  442   a  may be changed, such as the plurality of windows  442   a  being arranged in the up-down direction. 
     At least any of two kinds of the locking pins  140 ,  240 , and  340 , and the balls  440  of the first to fourth embodiment may be mixed. 
     In the first to third embodiments, the retainer  442  according to the fourth embodiment may be used.