Patent Publication Number: US-2023160223-A1

Title: Rebar tying tool and reel

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-188815, filed on Nov. 19, 2021, the entire contents of which are hereby incorporated by reference into the present application. 
     TECHNICAL FIELD 
     The disclosure herewith relates to rebar tying tools and reels. 
     BACKGROUND 
     Japanese Patent Application Publication No. 2017-24908 describes a rebar tying tool. The rebar tying tool includes a reel having a bobbin and a wire wound around the bobbin, wherein the bobbin includes a detection target portion; a reel attaching part to which the reel is rotatably attached; a feeding unit configured to feed the wire from the bobbin around rebars; a twisting unit configured to twist the wire around the rebars; a photointerrupter configured to detect the detection target portion; and a support supporting the reel attaching part, the feeding unit, the twisting unit, and the photointerrupter. The detection target portion is an annular rib arranged about a center axis of the bobbin. The photointerrupter is configured to detect the annular rib as the reel rotates. 
     SUMMARY 
     According to rebar tying tools such as the one above, the photointerrupter cannot detect the annular rib unless the reel rotates once. Thus, specific information of the reel cannot be detected unless the reel rotates once. The disclosure herein provides a technology that enables detection of specific information of a reel before the reel finishes rotating once. 
     A rebar tying tool disclosed herein may comprise: a reel comprising a bobbin and a wire wound around the bobbin, wherein the bobbin comprises a detection target portion; a reel attaching part to which the reel is rotatably attached; a feeding unit configured to feed the wire from the bobbin around rebars; a twisting unit configured to twist the wire around the rebars; a plurality of detectors configured to detect the detection target portion; and a support supporting the reel attaching part, the feeding unit, the twisting unit, and the plurality of detectors. The plurality of detectors may be disposed along a rotation direction of the reel and configured to detect the detection target portion as the reel rotates. 
     According to the configuration above, the plurality of detectors is disposed along the rotation direction of the reel, and thus the detection target portion can be detected before the reel finishes rotating once. Thus, specific information of the reel can be detected before the reel finishes rotating once. 
     A rebar tying tool disclosed herein may comprise: a reel attaching part to which a reel is rotatably attached, wherein the reel comprises a bobbin including a detection target portion and a wire wound around the bobbin; a feeding unit configured to feed the wire from the bobbin around rebars; a twisting unit configured to twist the wire around the rebars; a plurality of detectors configured to detect the detection target portion; and a support supporting the reel attaching part, the feeding unit, the twisting unit, and the plurality of detectors. The plurality of detectors may be disposed along a rotation direction of the reel and configured to detect the detection target portion as the reel rotates. 
     The configuration above can achieve the same effects as those of the rebar tying tool above. 
     A reel disclosed herein may be used by being rotatably attached to a reel attaching part of a rebar tying tool. The reel may comprise: a bobbin comprising a detection target portion; and a wire wound around the bobbin. The rebar tying tool may comprise a plurality of detectors disposed along a rotation direction of the reel. The detection target portion may include type information that indicates a type of the reel. The detection target portion may be detected by the plurality of detectors as the reel rotates. 
     According to the configuration above, the plurality of detectors is disposed along the rotation direction of the reel, and as such, after the reel is attached to the reel attaching part of the rebar tying tool, the detection target portion is detected before the reel finishes rotating once. Thus, the configuration can cause the rebar tying tool to detect specific information of the reel before the reel finishes rotating once. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a rebar tying tool  2  according to a first embodiment, as viewed from the upper left rear side. 
         FIG.  2    is a perspective view of the rebar tying tool  2  according to the first embodiment, as viewed from the upper right front side. 
         FIG.  3    is a side view of an internal configuration of the rebar tying tool  2  according to the first embodiment. 
         FIG.  4    is a perspective view of a feeding unit  38  according to the first embodiment. 
         FIG.  5    is a perspective view of the feeding unit  38  and a reel holder  10  according to the first embodiment. 
         FIG.  6    is a cross-sectional view of the rebar tying tool  2  according to the first embodiment, in the vicinity of its upper front portion. 
         FIG.  7    is a side view of a cutter unit  44  according to the first embodiment, illustrating a state before a first lever  76  and a second lever  78  pivot. 
         FIG.  8    is a side view of the cutter unit  44  according to the first embodiment, illustrating a state after the first lever  76  and the second lever  78  has pivoted. 
         FIG.  9    is a perspective view of a twisting unit  46  according to the first embodiment. 
         FIG.  10    is a cross-sectional view of a twisting motor  86 , a reducer  88 , and a retainer  90  according to the first embodiment. 
         FIG.  11    is an exploded perspective view of a carrier sleeve  98 , a clutch plate  100 , and a screw shaft  102  according to the first embodiment. 
         FIG.  12    is a perspective view of a clamp shaft  110  according to the first embodiment. 
         FIG.  13    is a perspective view of the twisting unit  46  according to the first embodiment, illustrating a state where a right clamp  112  and a left clamp  114  are attached to the clamp shaft  110 . 
         FIG.  14    is a perspective view of the right clamp  112  according to the first embodiment. 
         FIG.  15    is a perspective view of the left clamp  114  according to the first embodiment. 
         FIG.  16    is a perspective view of the twisting motor  86 , the reducer  88 , and the retainer  90  according to the first embodiment. 
         FIG.  17    is a perspective view of a rotation restrictor  92  according to the first embodiment. 
         FIG.  18    is a cross-sectional view of the reel holder  10  and a reel  33  according to the first embodiment. 
         FIG.  19    is a perspective view of a bobbin  160  of the reel  33  according to the first embodiment. 
         FIG.  20    is a perspective view of the reel holder  10  according to the first embodiment, illustrating a state where a main cover  28  is removed. 
         FIG.  21    is a perspective view of the reel holder  10  according to the first embodiment, illustrating a state where an auxiliary cover  30  is removed. 
         FIG.  22    is a perspective view of a right reel attaching part  190  and a type detecting device  220  according to the first embodiment. 
         FIG.  23    is an exploded perspective view of a turntable  198  and the type detecting device  220  according to the first embodiment. 
         FIG.  24    is a perspective view of the right reel attaching part  190  and support members  228  according to the first embodiment. 
         FIG.  25    is a top view of the reel  33 , a type detecting mechanism  158 , and the right reel attaching part  190  according to the first embodiment. 
         FIG.  26    is a right side view of the type detecting mechanism  158  and the right reel attaching part  190  according to the first embodiment. 
         FIG.  27    is a cross-sectional view of a reel  33 , the type detecting mechanism  158 , and the right reel attaching part  190  according to the first embodiment. 
         FIG.  28    illustrates signal charts detected by type-detecting magnetic sensors  222  and rotation-detecting magnetic sensors  248  according to the first embodiment. 
         FIG.  29    is a right side view of a type detecting mechanism  158  and a right reel attaching part  190  according to a second embodiment. 
         FIG.  30    illustrates signal charts detected by type-detecting magnetic sensors  222  and rotation-detecting magnetic sensors  248  according to the second embodiment. 
         FIG.  31    is a right side view of a type detecting mechanism  158  and a right reel attaching part  190  according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Representative, non-limiting examples of the present disclosure will now be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to provide improved rebar tying tools and reels, as well as methods for using and manufacturing the same. 
     Moreover, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the present disclosure in the broadest sense, and are instead taught merely to particularly describe representative examples of the present disclosure. Furthermore, various features of the above-described and below-described representative examples, as well as the various independent and dependent claims, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings. 
     All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter. 
     In one or more embodiments, the reel attaching part may comprise a turntable rotatably supported by the support. The bobbin may be fixed to the turntable when the reel is attached to the reel attaching part. 
     According to the configuration above, since the turntable is supported by the support, there is no need to attach/detach the turntable to/from the support. Thus, displacement of a rotation axis of the turntable can be suppressed. Displacement of a rotation axis of the reel thus can be suppressed. 
     In one or more embodiments, the rebar tying tool may further comprise a movable member movably supported by the turntable. The detection target portion may comprise a projection. The movable member may be at an initial position when the reel is not attached to the reel attaching part. The projection may be configured to push the movable member toward an attaching position when the reel is attached to the reel attaching part. Each of the plurality of detectors may be configured to detect the detection target portion by detecting the movable member at the attaching position. 
     According to the configuration above, specific information of the reel can be detected with a simple configuration of detecting the position of the movable member, before the reel finishes rotating once. 
     In one or more embodiments, the rebar tying tool may further comprise a type-detecting magnet fixed to the movable member. Each of the plurality of detectors may comprise a type-detecting magnetic sensor configured to detect whether the movable member is at the attaching position by detecting the type-detecting magnet. 
     In case of using an optical sensor, for example, a photointerrupter, the detection sensitivity of the photointerrupter may be decreased if the photointerrupter is contaminated by a foreign matter, etc. or if the photointerrupter is exposed to scattering light. According to the configuration above, the type-detecting magnetic sensor detects whether the movable member is at the attaching position or not, for example, by detecting magnetic variations caused by the type-detecting magnet. Whether the movable member is at the attaching position or not can be detected without the influence of contamination by foreign matters and scattering light, as compared to using a photointerrupter. 
     In one or more embodiments, the rebar tying tool may further comprise a biasing member configured to bias the movable member toward the initial position when the reel is detached from the reel attaching part. 
     According to the configuration above, the movable member can be returned to the initial position when the reel is detached from the reel attaching part. 
     In one or more embodiments, the bobbin may comprise: a trunk around which the wire is wound; and a flange disposed at one end of the trunk. The projection may project outward beyond an outer surface of the flange along a rotation axis of the reel. The turntable may comprise a receiver configured to receive and engage with the projection. 
     According to the configuration above, the reel can be fixed to the turntable with a simple configuration. 
     In one or more embodiments, each of the plurality of detectors may comprise a rotation detector configured to detect a rotation angle of the reel. 
     According to the configuration above, the detectors can be used to detect not only the type of the reel but also the rotation of the reel. 
     In one or more embodiments, the rebar tying tool may further comprise a rotation-detecting magnet configured to integrally rotate with the reel. Each rotation detector may comprise a rotation-detecting magnetic sensor configured to detect the rotation angle of the reel by detecting the rotation-detecting magnet. 
     In case of using an optical sensor, for example, a photointerrupter, the detection sensitivity may be decreased if the photointerrupter is contaminated by a foreign matter, etc. or if the photointerrupter is exposed to scattering light. According to the configuration above, the rotation-detecting magnetic sensors detect the rotation angle of the reel, for example, by detecting magnetic variations caused by the rotation-detecting magnet. The rotation angle of the reel can be detected without the influence of contamination by foreign matters and scattering light, as compared to using a photointerrupter. 
     In one or more embodiments, the plurality of detectors may be fixed to the support. 
     According to the configuration above, the position of the plurality of detectors does not change even when the reel rotates. Thus, the detection target portion can be detected accurately by the plurality of detectors. 
     In one or more embodiments, the plurality of detectors may comprise N detectors, wherein the N is an integer greater than or equal to 2. The detectors adjacent to each other may be disposed along the rotation direction at intervals corresponding to an angle of 360/N degrees. 
     According to the configuration above, specific information of the reel can be detected by the reel rotating by the angle of 360/N degrees. 
     In one or more embodiments, the plurality of detectors may comprise N detectors, wherein the N is an integer greater than or equal to 2. A maximum interval between the detectors adjacent to each other may be an interval corresponding to a specific angle that is greater than an angle of 360/N degrees along the rotation direction. 
     According to the configuration above, specific information of the reel can be detected by the reel rotating by the specific angle that is smaller than an angle of 360 degrees. 
     First Embodiment 
     As shown in  FIG.  1   , a rebar tying tool  2  is configured to tie a plurality of rebars R with a wire W. For example, the rebar tying tool  2  ties, with the wire W, rebars R having a small diameter of 16 mm or less or rebars R having a large diameter of greater than 16 mm (e.g., 25 mm or 32 mm). The diameter of the wire W is, for example, within a range from 0.5 mm to 2.0 mm. 
     As shown in  FIG.  1   , the rebar tying tool  2  comprises a main body  4 , a grip  6 , a battery attaching part  8 , a battery pack B, and a reel holder  10 . The grip  6  is configured to be gripped by an operator. The grip  6  is disposed at a lower rear portion of the main body  4 . The grip  6  is integral with the main body  4 . A trigger  12  is disposed at an upper front portion of the grip  6 . A trigger switch  14  (see  FIG.  3   ) configured to detect whether the trigger  12  is pressed or not is disposed within the grip  6 . The battery attaching part  8  is disposed at a lower portion of the grip  6 . The battery attaching part  8  is integral with the grip  6 . The battery pack B can be attached to and detached from the battery attaching part  8  by being slid with respect to the battery attaching part  8 . The battery pack B comprises, for example, secondary batteries such as lithium-ion batteries. The reel holder  10  is disposed at a lower front portion of the main body  4 . The reel holder  10  is disposed forward of the grip  6 . In the present embodiment, a longitudinal direction of a twisting unit  46  (which will be described later) is termed a front-rear direction, a direction perpendicular to the front-rear direction is termed an up-down direction, and a direction perpendicular to the front-rear direction and the up-down direction is termed a right-left direction. 
     The rebar tying tool  2  comprises a housing  16 . The housing  16  constitutes a part of a support  15 . As shown in  FIG.  2   , the housing  16  comprises a right housing  18 , a left housing  20 , and a motor cover  22 . The right housing  18  defines shapes of right halves of the main body  4 , the grip  6 , and the battery attaching part  8 . The left housing  20  defines shapes of left halves of the main body  4 , the grip  6 , and the battery attaching part  8 . The motor cover  22  is attached to an outer side of the right housing  18 . As shown in  FIG.  1   , an operation display  24  is disposed at an upper rear portion of the left housing  20 . The operation display  24  comprises a main power switch  24   a  and a main power LED  24   b . The main power switch  24   a  is configured to receive an operation to turn on/turn off the rebar tying tool  2  from the user. The main power LED  24   b  is configured to display whether the rebar tying tool  2  is on or off. 
     As shown in  FIG.  2   , the reel holder  10  comprises a holder housing  26 , a main cover  28 , and an auxiliary cover  30 . The holder housing  26  and the auxiliary cover  30  constitute a part of the support  15 . The holder housing  26  is fixed to the lower front portion of the main body  4  and a front portion of the battery attaching part  8 . The holder housing  26  includes an opening at its left end. The main cover  28  is attached to the holder housing  26  such that the main cover  28  is pivotable about a pivot axis  26   a  at a lower portion of the holder housing  26 . The main cover  28  is biased in its opening direction by a torsion spring  31  (see  FIG.  3   ). A closed state detecting sensor (not shown) configured to detect that the main cover  28  is in a closed state is attached to the holder housing  26 . The auxiliary cover  30  covers a right surface of the holder housing  26 . The auxiliary cover  30  defines an auxiliary space  30   a  between the right surface of the holder housing  26  and the auxiliary cover  30 . 
     As shown in  FIG.  1   , a lock lever  32  for keeping the main cover  28  closed is disposed at a lower front portion of the left housing  20 . When the lock lever  32  is pivoted, the main cover  28  is opened with respect to the holder housing  26  by the biasing force of the torsion spring  31  (see  FIG.  3   ). While the main cover  28  is in the closed state, a housing space  26   b  (see  FIG.  3   ) is defined by the holder housing  26  and the main cover  28 . A reel  33  (see  FIG.  3   ) comprising the wire W is disposed in the housing space  26   b . As shown in  FIG.  2   , a hole  26   c  is defined in a front surface of the holder housing  26 . The user can check a remaining amount of the wire W on the reel  33  by seeing the reel  33  through the hole  26   c.    
     As shown in  FIG.  3   , the rebar tying tool  2  comprises a control circuit board  36 . The control circuit board  36  is disposed within the battery attaching part  8 . The control circuit board  36  is electrically connected to each of the battery pack B, the trigger switch  14 , and the operation display  24  via wires which are not shown. Further, the control circuit board  36  is electrically connected to the closed state detecting sensor (not shown) attached to the holder housing  26  via a wire which is not shown. 
     The rebar tying tool  2  comprises a feeding unit  38 , a guiding unit  40 , a cutter unit  44 , and a twisting unit  46 . The feeding unit  38  is disposed within the front lower portion of the main body  4 . The guiding unit  40  is disposed at a front portion of the main body  4 . The cutter unit  44  is disposed within a lower portion of the main body  4 . The twisting unit  46  is disposed within the body  4 . 
     As shown in  FIG.  4   , the feeding unit  38  comprises a feeding motor  50 , a reducer  52 , and a feeder  54 . The feeding motor  50  is, for example, a brushless motor. The feeding motor  50  is disposed rightward of the right housing  18  (see  FIG.  2   ) and is covered by the motor cover  22  (see  FIG.  2   ). The feeding motor  50  is electrically connected to the control circuit board  36  via a wire which is not shown. The feeding motor  50  operates by electric power supplied from the battery pack B (see  FIG.  2   ). 
     The reducer  52  comprises, for example, a planetary gear mechanism. The reducer  52  is configured to reduce the rotational speed of the feeding motor  50 . 
     The feeder  54  comprises a base  56 , a guide  58 , a drive gear  60 , a first feed gear  62 , a second feed gear  64 , a release lever  66 , and a compression spring  68 . The guide  58  is fixed to the base  56 . The guide  58  has a guide hole  58   a . The guide hole  58   a  has a tapered shape with a broad lower end and a narrower upper end. The wire W is inserted through the guide hole  58   a.    
     Rotation is transmitted to the drive gear  60  from the reducer  52 . The first feed gear  62  is rotatably supported by the base  56 . The first feed gear  62  is meshed with the drive gear  60 . The first feed gear  62  is rotated by the rotation of the drive gear  60 . The first feed gear  62  has a groove  62   a . The groove  62   a  is defined in an outer circumferential surface of the first feed gear  62  and extends in a direction along a rotation direction of the first feed gear  62 . The second feed gear  64  is configured to mesh with the first feed gear  62 . The second feed gear  64  is rotatably supported by the release lever  66 . The second feed gear  64  has a groove  64   a . The groove  64   a  is defined in an outer circumferential surface of the second feed gear  64  and extends in a direction along a rotation direction of the second feed gear  64 . The release lever  66  is swingably supported by the base  56  via a swing shall  66   a . The compression spring  68  biases the release lever  66  with respect to the right housing  18  (see  FIG.  2   ) in a direction that brings the second feed gear  64  closer to the first feed gear  62 . Thus, the second feed gear  64  is pressed against the first feed gear  62 . The wire W is thereby held between the groove  62   a  of the first feed gear  62  and the groove  64   a  of the second feed gear  64 . As shown in  FIG.  5   , when the lock lever  32  is pivoted in a direction that releases the retention of the main cover  28 , a lower end of the release lever  66  is pushed by the lock lever  32  to move toward the right housing  18 . The second feed gear  64  is thereby separated away from the first feed gear  62 . In this state, the user can place the wire W of the reel  33  (see  FIG.  4   ) between the groove  62   a  of the first feed gear  62  and the groove  64   a  of the second feed gear  64 . As shown in  FIG.  2   , a window  16   a  is defined in front surfaces of the left housing  20  and the motor cover  22 , and the user can see a site where the first feed gear  62  meshes with the second feed gear  64  through the window  16   a.    
     The wire W is moved when the feeding motor  50  rotates with the wire W held between the groove  62   a  of the first feed gear  62  and the groove  64   a  of the second feed gear  64 , as shown in  FIG.  4   . In the present embodiment, when the feeding motor  50  rotates forward, the drive gear  60  is rotated in a direction D 1  shown in  FIG.  4    and the wire W is fed out from the reel  33  toward the guiding unit  40 . When the feeding motor  50  rotates in reverse, the drive gear  60  is rotated in a direction D 2  shown in  FIG.  4    and the wire W is pulled back toward the reel  33  from the feeding unit  38 . 
     As shown in  FIG.  6   , the guiding unit  40  comprises an upper curl guide  70  and a lower curl guide  71 . The upper curl guide  70  and the lower curl guide  71  are disposed at the front portion of the main body  4 . A lower end of the upper curl guide  70  is open downward. Thereby, an upper wire passage  70   a  is defined in the upper curl guide  70 . The lower curl guide  71  is disposed below the upper curl guide  70 . An upper end of the upper curl guide  70  is open upward. Thereby, a lower wire passage  71   a  is defined in the lower curl guide  71 . 
     The wire W fed out from the feeding unit  38  (see  FIG.  4   ) is directed into the upper wire passage  70   a . The wire W passes through the upper wire passage  70   a  from the rear toward the front. During this passing, a downward curl is given to the wire W. After passing through the upper wire passage  70   a , the wire W is directed into the lower wire passage  71   a . The wire W passes through the lower wire passage  71   a  from the front toward the rear. Thus, the wire W is wound around the rebars R. 
     As shown in  FIG.  7   , the cutter unit  44  comprises a fixed cutter  72 , a movable cutter  74 , a first lever  76 , a second lever  78 , a link  80 , and a torsion spring  82 . As shown in  FIG.  6   , the fixed cutter  72  and the movable cutter  74  are disposed on the path along which the wire W is directed to the guiding unit  40  from the feeding unit  38 . The fixed cutter  72  has a hole  72   a  through which the wire W passes. The movable cutter  74  is supported by the fixed cutter  72  such that the movable cutter  74  can slide along and rotate about the fixed cutter  72 . The movable cutter  74  has a hole  74   a  through which the wire W can pass. When the hole  74   a  of the movable cutter  74  is in communication with the hole  72   a  of the fixed cutter  72  (this state may be termed “communicated state” hereinbelow) as shown in  FIG.  7   , the wire W can pass through the hole  72   a  of the fixed cutter  72  and the hole  74   a  of the movable cutter  74 . Then, when the movable cutter  74  is rotated with respect to the fixed cutter  72  in a direction D 3  shown in  FIG.  6    (this state may be termed “cutting state” hereinbelow), the wire W is cut by the fixed cutter  72  and the movable cutter  74 . 
     As shown in  FIG.  7   , the first lever  76  and the second lever  78  are fixed to each other. The first lever  76  and the second lever  78  are swingable about an axis RX. Lower ends of the first lever  76  and the second lever  78  are rotatably coupled to a rear end of the link  80 . A front end of the link  80  is rotatably coupled to a lower end of the movable cutter  74 . The rear end of the link  80  is biased forward by the torsion spring  82 . When the lower ends of the first lever  76  and the second lever  78  are swung forward, the link  80  is moved forward and the fixed cutter  72  and the movable cutter  74  are thereby brought into the communicated state. When the lower ends of the first lever  76  and the second lever  78  are swung rearward, the link  80  is moved rearward and the fixed cutter  72  and the movable cutter  74  are thereby brought into the cutting state. 
     As shown in  FIG.  9   , the twisting unit  46  comprises a twisting motor  86 , a reducer  88 , a retainer  90 , and a rotation restrictor  92 . The twisting motor  86  is, for example, a brushless motor. The twisting motor  86  is fixed to the right housing  18  (see  FIG.  1   ) and the left housing  20  (see  FIG.  1   ). The twisting motor  86  is electrically connected to the control circuit board  36  (see  FIG.  3   ) via a wire which is not shown. The twisting motor  86  operates by electric power supplied from the battery pack B (see  FIG.  1   ). 
     The reducer  88  is fixed to the right housing  18  and the left housing  20 . The reducer  88  comprises, for example, a planetary gear mechanism. The reducer  88  is configured to reduce the rotational speed of the twisting motor  86 . 
     As shown in  FIG.  10   , the retainer  90  comprises a bearing box  96 , a carrier sleeve  98 , a clutch plate  100 , a screw shaft  102 , an inner sleeve  104 , an outer sleeve  106 , a push plate  108 , a clamp shaft  110 , a right clamp  112 , and a left clamp  114 . 
     The bearing box  96  is fixed to the reducer  88 . The bearing box  96  supports the carrier sleeve  98  via a bearing  96   a  such that the carrier sleeve  98  is rotatable. Rotation is transmitted to the carrier sleeve  98  from the reducer  88 . When the twisting motor  86  rotates forward, the carrier sleeve  98  is rotated counterclockwise as viewed from the rear. When the twisting motor  86  rotates in reverse, the carrier sleeve  98  is rotated clockwise as viewed from the rear. 
     As shown in  FIG.  11   , a clutch groove  98   a  extending in the front-rear direction is defined in an inner surface of a rear portion of the carrier sleeve  98 . The clutch groove  98   a  includes a first wall  98   b  and a second wall  98   c  at its front ends. A distance from a rear end of the carrier sleeve  98  to the first wall  98   b  in the front-rear direction is shorter than a distance from the rear end of the carrier sleeve  98  to the second wall  98   c  in the front-rear direction. The clutch plate  100  is disposed inside the carrier sleeve  98 . The clutch plate  100  includes a clutch piece  100   a  corresponding to the clutch groove  98   a . The clutch plate  100  is biased rearward with respect to the carrier sleeve  98  by a compression spring  116  disposed inside the carrier sleeve  98 . The clutch plate  100  is movable forward with respect to the carrier sleeve  98  until the clutch piece  100   a  contacts the first wall  98   b  of the clutch groove  98   a . When the wire W is twisted, the carrier sleeve  98  is rotated counterclockwise with respect to the clutch plate  100  as viewed from the rear, and thus the clutch plate  100  can move forward with respect to the carrier sleeve  98  until the clutch piece  100   a  contacts the second wall  98   c  of the clutch groove  98   a.    
     A rear portion  102   a  of the screw shaft  102  is inserted into the carrier sleeve  98  from the front and is fixed to the clutch plate  100 . The screw shaft  102  includes a radially protruding flange  102   c  between the rear portion  102   a  and a front portion  102   b  of the screw shaft  102 . A spiral ball groove  102   d  is defined in an outer surface of the front portion  102   b  of the screw shaft  102 . The screw shaft  102  includes an engagement portion  102   e  at its front end, and a diameter of the engagement portion  102   e  is smaller than that of the front portion  102   b.    
     As shown in  FIG.  10   , a compression spring  118  is attached to the front portion  102   b  of the screw shall  102 . The front portion  102   b  of the screw shaft  102  is inserted into the inner sleeve  104  from the rear. A ball hole  104   a  configured to hold balls  120  is defined in the inner sleeve  104 . The balls  120  fit in a ball groove  102   d  of the screw shaft  102 . The inner sleeve  104  includes a radially protruding flange  104   b  at its rear end. The inner sleeve  104  is inserted into the outer sleeve  106  from the rear. The outer sleeve  106  is fixed to the inner sleeve  104 . In the case where the rotation restrictor  92  (see  FIG.  17   ) permits the outer sleeve  106  to rotate, the inner sleeve  104  and the outer sleeve  106  are integrally rotated when the screw shaft  102  rotates. In the case where the rotation restrictor  92  prohibits the outer sleeve  106  from rotating, the inner sleeve  104  and the outer sleeve  106  are moved in the front-rear direction with respect to the screw shaft  102  when the screw shaft  102  rotates. Specifically, when the screw shaft  102  rotates counterclockwise as viewed from the rear by the twisting motor  86  rotating forward, the inner sleeve  104  and the outer sleeve  106  are moved forward with respect to the screw shaft  102 . When the screw shaft  102  rotates clockwise as viewed from the rear by the twisting motor  86  rotating in reverse, the inner sleeve  104  and the outer sleeve  106  are moved rearward with respect to the screw shaft  102 . The push plate  108  is disposed between the rear end of the outer sleeve  106  and the flange  104   b  of the inner sleeve  104 . Thus, the push plate  108  is also moved in the front-rear direction when the inner sleeve  104  and the outer sleeve  106  are moved in the front-rear direction. Slits  106   a  extending rearward from a front end of the outer sleeve  106  are defined in the front portion of the outer sleeve  106 . 
     The clamp shaft  110  is inserted into the inner sleeve  104  from the front. The engagement portion  102   e  of the screw shaft  102  is inserted in a rear end of the clamp shaft  110 . The clamp shaft  110  is fixed to the screw shaft  102 . As shown in  FIG.  12   , the clamp shaft  110  includes a flat-plate portion  110   a , an opening  110   b , and a flange  110   c . The flat-plate portion  110   a  is disposed at a front end of the clamp shaft  110  and has a flat-plate shape along the front-rear direction and the up-down direction. A hole  110   d  in which a pin  122  (see  FIG.  13   ) fits is defined in the flat-plate portion  110   a . The opening  110   b  is disposed rearward of the flat-plate portion  110   a . The opening  110   b  penetrates the clamp shaft  110  in the right-left direction and extends in the front-rear direction. The flange  110   c  is disposed rearward of the opening  110   b  and protrudes radially. 
     As shown in  FIG.  13   , the right clamp  112  is attached to the clamp shaft  110  such that the right clamp  112  passes through the opening  110   b  of the clamp shaft  110  from the right to the left. Below the right clamp  112 , the left clamp  114  is attached to the clamp shaft  110  such that the left clamp  114  passes through the opening  110   b  of the clamp shaft  110  from the left to the right. 
     As shown in  FIG.  14   , the right clamp  112  comprises a base  112   a , a downward protrusion  112   b , an upward protrusion  112   c , a contact portion  112   d , an upper guard  112   e , and a front guard  112   f  The base  112   a  has a flat-plate shape along the front-rear direction and the right-left direction. The downward protrusion  112   b  is disposed at a right front end of the base  112   a  and protrudes downward from the base  112   a . The upward protrusion  112   c  is disposed at the right front end of the base  112   a  and protrudes upward from the base  112   a . The contact portion  112   d  protrudes leftward from an upper end of the upward protrusion  112   c . The upper guard  112   e  protrudes leftward from an upper end of the contact portion  112   d . The front guard  112   f  protrudes leftward from front ends of the upward protrusion  112   c  and the contact portion  112   d . Cam holes  112   g ,  112   h  are defined in the base  112   a . From their rear ends toward front ends, the cam holes  112   g ,  112   h  extend forward from their rear ends, bend to extend diagonally forward right, and then bend again to extend forward. 
     As shown in  FIG.  15   , the left clamp  114  comprises a base  114   a , a pin retainer  114   b , a downward protrusion  114   c , a contact portion  114   d , a rear guard  114   e , and a front guard  114   f . The base  114   a  has a flat-plate shape along the front-rear direction and the right-left direction. The pin retainer  114   b  is disposed at a left front end of the base  114   a  and retains the pin  122  (see  FIG.  13   ) above the base  114   a  such that the pin  122  is slidable. The downward protrusion  114   c  is disposed at the left front end of the base  114   a  and protrudes downward from the base  114   a . The contact portion  114   d  protrudes rightward from a lower end of the downward protrusion  114   c . The rear guard  114   e  protrudes rightward from a rear end of the contact portion  114   d . The front guard  114   f  protrudes rightward from a front end of the contact portion  114   d . Cam holes  114   g ,  114   h  are defined in the base  114   a . From their rear ends toward front ends, the cam holes  114   g ,  114   h  extend forward from their rear ends, bend to extend diagonally forward left, bend again to extend forward, bend to extend diagonally forward left again, and then bend to extend forward. 
     As shown in  FIG.  13   , in the state where the right clamp  112  and the left clamp  114  are attached to the clamp shall  110 , a cam sleeve  124  extend through the cam holes  112   g  and  114   g  and a cam sleeve  126  extends through the cam holes  112   h  and  114   h . Further, a support pin  128  extends through the cam sleeve  124  and a support pin  130  extend through the cam sleeve  126 . An annular cushion  131  is attached between the right clamp  112  and the left clamp  114  and the flange  110   c  of the clamp shaft  110 . 
     As shown in  FIG.  9   , in the state where the clamp shaft  110  is attached to the inner sleeve  104 , the right clamp  112  and the left clamp  114  are in the slits  106   a  of the outer sleeve  106  and the support pins  128 ,  130  are coupled with the outer sleeve  106 . When the clamp shaft  110  is moved in the front-rear direction with respect to the outer sleeve  106 , the cam sleeve  124  attached to the support pin  128  is moved within the cam holes  112   g ,  114   g  in the front-rear direction and the cam sleeve  126  attached to the support pin  130  is moved within the cam holes  112   h ,  114   h  in the front-rear direction, and thereby the right clamp  112  and the left clamp  114  are moved in the right-left direction. 
     As shown in  FIG.  13   , in an initial state where the clamp shaft  110  protrudes forward from the outer sleeve  106 , the right clamp  112  is positioned furthest to the right from the left clamp  114 . In this state, a right wire passage  132  through which the wire W can pass is defined between the upward protrusion  112   c  of the right clamp  112  and the flat-plate portion  110   a  of the clamp shaft  110 , and the upper guard  112   e  covers the right wire passage  132  from above. This state of the right clamp  112  is termed a fully-open state. When the outer sleeve  106  is moved forward with respect to the clamp shaft  110  in that state, the right clamp  112  is moved leftward toward the clamp shaft  110 . In this state, the wire W is held between a lower end of the contact portion  112   d  of the right clamp  112  and an upper end of the flat-plate portion  110   a  of the clamp shaft  110  and a front end of the right wire passage  132  is covered by the front guard  112   f . This state of the right clamp  112  is termed a fully-closed state. 
     In the initial state where the clamp shaft  110  protrudes forward from the outer sleeve  106 , the left clamp  114  is positioned furthest to the left from the clamp shaft  110 . In this state, a left wire passage  134  through which the wire W can pass is defined between the downward protrusion  114   c  of the left clamp  114  and the flat-plate portion  110   a  of the clamp shaft  110 . This state of the left clamp  114  is termed a fully-open state. When the outer sleeve  106  is moved forward with respect to the clamp shaft  110  in that state, the left clamp  114  is moved rightward toward the clamp shaft  110 . The wire W can still pass through the left wire passage  134  in this state, while a rear end of the left wire passage  134  is covered by the rear guard  114   e  and a front end of the left wire passage  134  is covered by the front guard  114   f . This state of the left clamp  114  is termed a half-open state. When the outer sleeve  106  is moved further forward with respect to the clamp shaft  110 , the left clamp  114  is moved further rightward toward the clamp shaft  110 . In this state, the wire W is held between an upper end of the contact portion  114   d  of the left clamp  114  and a lower end of the flat-plate portion  110   a  of the clamp shaft  110 . This state of the left clamp  114  is termed a fully-closed state. 
     On the way from the feeding unit  38  (see  FIG.  6   ) to the guiding unit  40  (see  FIG.  6   ), the wire W passes through the left wire passage  134  before reaching the guiding unit  40 . Thus, when the wire W is cut by the cutter unit  44  (see  FIG.  6   ) with the left clamp  114  in the fully-closed state, a proximal end of the wire W wound around the rebars R is held by the left clamp  114  and the clamp shaft  110 . 
     Further, the wire W guided through the guiding unit  40  passes through the right wire passage  132 . Thus, when the right clamp  112  is brought into the fully-closed state, a distal end of the wire W wound around the rebars R is held by the right clamp  112  and the clamp shaft  110 . 
     As shown in  FIG.  16   , the outer sleeve  106  includes fins  138  on an outer surface of its rear portion. The fins  138  extend in the front-rear direction. In the present embodiment, eight fins  138  are arranged on the outer surface of the outer sleeve  106  with intervals of 45 degrees from each other. Further, in the present embodiment, the eight fins  138  comprise seven short fins  138   a  and one long fin  138   b . A length of the long fin  138   b  in the front-rear direction is greater than a length of the short fins  138   a  in the front-rear direction. In the front-rear direction, the position of a rear end of the long fin  138   b  is coincident with the positions of rear ends of the short fins  138   a . In the front-rear direction, the position of a front end of the long fin  138   b  is forward of the positions of front ends of the short fins  138   a.    
     The rotation restrictor  92  is disposed corresponding to the fins  138  of the outer sleeve  106 . The rotation restrictor  92  is configured to permit or prohibit the rotation of the outer sleeve  106  in cooperation with the fins  138 . As shown in  FIG.  17   , the rotation restrictor  92  comprises a base  140 , an upper stopper  142 , a lower stopper  144 , and torsion springs  146 ,  148 . The base  140  is fixed to the right housing  18  (see  FIG.  1   ). The upper stopper  142  is swingably supported by an upper portion of the base  140  via a swing shaft  140   a . The upper stopper  142  comprises a restriction piece  142   a . The restriction piece  142   a  is disposed at a lower portion of the upper stopper  142 . The torsion spring  146  biases the restriction piece  142   a  in an outwardly opening direction (i.e., in a direction that brings the restriction piece  142   a  away from the base  140 ). The lower stopper  144  is swingably supported by a lower portion of the base  140  via a swing shaft  140   b . The lower stopper  144  comprises a restriction piece  144   a . The restriction piece  144   a  is disposed at an upper portion of the lower stopper  144 . A rear end of the restriction piece  144   a  is positioned forward of a rear end of the restriction piece  142   a . The torsion spring  148  biases the restriction piece  144   a  in an outwardly opening direction (i.e., in a direction that brings the restriction piece  144   a  away from the base  140 ). 
     When the screw shaft  102  (see  FIG.  10   ) is rotated counterclockwise as viewed from the rear by the twisting motor  86  (see  FIG.  10   ) rotating forward, the rotation of the outer sleeve  106  is prohibited by the upper stopper  142  upon the restriction piece  142   a  contacting one of the fins  138  (see  FIG.  16   ) of the outer sleeve  106 . To the contrary, when the screw shaft  102  is rotated clockwise as viewed from the rear by the twisting motor  86  rotating in reverse, one of the fins  138  of the outer sleeve  106  contacts the restriction piece  142   a  and pushes in the restriction piece  142   a . In this case, the upper stopper  142  does not prohibit the rotation of the outer sleeve  106 . 
     When the screw shaft  102  is rotated counterclockwise as viewed from the rear by the twisting motor  86  rotating forward, one of the fins  138  of the outer sleeve  106  contacts the restriction piece  144   a  of the lower stopper  144  and pushes in the restriction piece  144   a . In this case, the lower stopper  144  does not prohibit the rotation of the outer sleeve  106 . To the contrary, when the screw shaft  102  is rotated clockwise as viewed from the rear, the rotation of the outer sleeve  106  is prohibited by the lower stopper  144  upon the restriction piece  144   a  contacting one of the fins  138  of the outer sleeve  106 . 
     Next, operation of the rebar tying tool  2  shown in  FIG.  1    will be described. The rebar tying tool  2  performs a tying operation when the trigger  12  is operated by the operator. During the tying operation by the rebar tying tool  2 , a feeding process, a distal end retaining process, a pull-back process, a proximal end retaining process, a cutting process, a twisting process, and a returning process are performed. 
     (Feeding Process) 
     When the feeding motor  50  shown in  FIG.  4    rotates forward (that is, rotates in the direction D 1  shown in  FIG.  4   ) in the initial state of the rebar tying tool  2 , the feeding unit  38  feeds out the wire W on the reel  33  by a predetermined length. The distal end of the wire W passes through the fixed cutter  72 , the movable cutter  74 , the left wire passage  134 , the guiding unit  40 , and the right wire passage  132  in this order. As a result, the wire W is wound around the rebars R in a loop shape. The feeding motor  50  is stopped upon completion of the feed-out of the wire W. 
     (Distal End Retaining Process) 
     When the twisting motor  86  shown in  FIG.  10    rotates forward after the completion of the feeding process, the screw shaft  102  rotates counterclockwise. At this occasion, the outer sleeve  106  is prohibited from rotating counterclockwise by the rotation restrictor  92 . Thus, the outer sleeve  106  moves forward together with the inner sleeve  104  with respect to the clamp shaft  110 , the right clamp  112  is brought into the fully-closed state, and the left clamp  114  is brought into the half-open state. The distal end of the wire W is thereby retained by the right clamp  112  and the clamp shaft  110 . The twisting motor  86  is stopped when the retention of the distal end of the wire W is detected. 
     (Pull-Back Process) 
     When the feeding motor  50  shown in  FIG.  4    rotates in reverse (that is, in the direction D 2  shown in  FIG.  4   ) after the completion of the distal end retaining process, the feeding unit  38  pulls back the wire W wound around the rebars R. Since the distal end of the wire W is retained by the right clamp  112  and the clamp shaft  110 , the diameter of the loop formed by the wire W around the rebars R is decreased. The feeding motor  50  is stopped upon completion of the pull-back of the wire W. 
     (Proximal End Retaining Process) 
     When the twisting motor  86  shown in  FIG.  10    rotates forward after the completion of the pull-back process, the screw shaft  102  rotates counterclockwise. At this occasion, the outer sleeve  106  is prohibited from rotating counterclockwise by the rotation restrictor  92 . Thus, the outer sleeve  106  further moves forward together with the inner sleeve  104  with respect to the clamp shaft  110  and the left clamp  114  is brought into the fully-closed state. The proximal end of the wire W is thereby retained by the left clamp  114  and the clamp shaft  110 . 
     (Cutting Process) 
     When the twisting motor  86  shown in  FIG.  10    further rotates forward after the completion of the proximal end retaining process, the screw shaft  102  rotates counterclockwise. At this occasion, the outer sleeve  106  is prohibited from rotating counterclockwise by the rotation restrictor  92 . Thus, the outer sleeve  106  further moves forward together with the inner sleeve  104  with respect to the clamp shaft  110  and the push plate  108  pushes the upper end of the second lever  78  forward as shown in  FIG.  8   . As a result, the wire W is cut by the fixed cutter  72  and the movable cutter  74 . The twisting motor  86  is stopped upon completion of the cutting of the wire W. 
     (Twisting Process) 
     When the twisting motor  86  shown in  FIG.  10    further rotates forward after the completion of the cutting process, the screw shaft  102  rotates counterclockwise. At this occasion, the outer sleeve  106  is permitted to rotate counterclockwise by the rotation restrictor  92 . Thus, the outer sleeve  106 , the inner sleeve  104 , the clamp shaft  110 , the right clamp  112 , and the left clamp  114  integrally rotate counterclockwise. The wire W wound around the rebars R is thereby twisted. The twisting motor  86  is stopped upon completion of the twisting of the wire W. 
     (Returning Process) 
     When the twisting motor  86  shown in  FIG.  10    rotates in reverse after the completion of the twisting process, the screw shaft  102  rotates clockwise. At this occasion, the outer sleeve  106  is prohibited from rotating clockwise by the rotation restrictor  92 . Thus, the outer sleeve  106  moves rearward together with the inner sleeve  104  with respect to the clamp shaft  110 , the left clamp  114  is brought into the fully-open state through the half-open state, and the right clamp  112  is brought into the fully-open state. Thereafter, when the clockwise rotation is permitted by the rotation restrictor  92 , the outer sleeve  106 , the inner sleeve  104 , the clamp shaft  110 , the right clamp  112 , and the left clamp  114  integrally rotate clockwise. When the long fin  138   b  contacts the lower stopper  144 , the rotation of the outer sleeve  106  is prohibited again and thus the outer sleeve  106  moves rearward again together with the inner sleeve  104  with respect to the clamp shaft  110 . The twisting motor  86  is stopped when the return of the twisting unit  46  to the initial state is detected. 
     For the rebar tying tool  2 , the thickness of the wire W varies depending on diameters of rebars R to be used. Further, depending on the environment in which the rebars R are used, etc., a wire W coated by a coat (e.g., a resin material) or a plated wire W can be used. The type of the reel  33  (see  FIG.  18   ) varies depending on the thickness of wire W, whether the wire W is coated or not, and/or whether the wire W is plated or not. Thus, the rebar tying tool  2  comprises a type detecting mechanism  158  (see  FIG.  18   ) for detecting the type of the reel  33 . 
     First, the reel  33  will be described. As shown in  FIG.  18   , the reel  33  is disposed in the housing space  26   b  of the reel holder  10 . The reel  33  is supported by the reel holder  10  such that the reel  33  is rotatable about a rotation axis AX extending in the right-left direction. The reel  33  comprises a bobbin  160  and the wire W. The central axis of the bobbin  160  is coincident with the rotation axis AX of the reel  33 . 
     As shown in  FIG.  19   , the bobbin  160  comprises a trunk  162 , a pair of flanges  164 ,  166 , and a plurality of projections  168  (six projections  168  in the present embodiment). Hereinafter, the pair of flanges  164 ,  166  may be separately termed a left flange  164  and a right flange  166 . For example, the trunk  162 , the pair of flanges  164 ,  166 , and the six projections  168  are constituted of a resin material. The trunk  162 , the pair of flanges  164 ,  166 , and the six projections  168  are integral with each other. 
     The trunk  162  comprises an outer cylinder  170 , an inner cylinder  172 , and a connection  174 . The outer cylinder  170  and the inner cylinder  172  have substantially cylindrical shapes. The wire W (see  FIG.  18   ) is wound around an outer circumferential surface of the outer cylinder  170  in multiple layers. The inner cylinder  172  is disposed inside the outer cylinder  170 . As shown in  FIG.  18   , an engagement groove  172   a  is defined in a right end portion of an inner circumferential surface of the inner cylinder  172 . A shaft receiving groove  172   b  is defined in a left end portion of the inner circumferential surface of the inner cylinder  172 . The connection  174  is disposed between an inner circumferential surface of the outer cylinder  170  and an outer circumferential surface of the inner cylinder  172 . The connection  174  connects the outer cylinder  170  to the inner cylinder  172 . 
     As shown in  FIG.  19   , the left flange  164  and the right flange  166  have broad disk shapes. The wire W (see  FIG.  18   ) is disposed between the left flange  164  and the right flange  166 . The left flange  164  is disposed at a left end of the trunk  162 . The left flange  164  extends radially outward from the outer circumferential surface of the outer cylinder  170 . The left flange  164  includes a lock groove  176  penetrating the left flange  164  in its thickness direction (in the right-left direction). The lock groove  176  comprises a guide portion  176   a  extending from an inner circumferential surface of the left flange  164  to an outer circumferential surface thereof, a base end locking portion  176   b  connected to the guide portion  176   a  near the inner circumferential surface of the left flange  164 , and a terminal end locking portion  176   c  connected to the guide portion  176   a  near the outer circumferential surface of the left flange  164 . One end of the wire W wound around the outer cylinder  170  is locked to the left flange  164  at the base end locking portion  176   b . The other end of the wire W wound around the outer cylinder  170  is locked to the left flange  164  at the terminal end locking portion  176   c.    
     The right flange  166  is disposed at a right end of the trunk  162 . The right flange  166  extends radially outward from the outer circumferential surface of the outer cylinder  170 . The diameter of the outer circumferential surface of the right flange  166  is smaller than the diameter of the outer circumferential surface of the left flange  164 . 
     The six projections  168  extend outward (rightward) along the rotation axis AX of the reel  33 , beyond an outer surface (right surface) of the right flange  166 , from between the inner circumferential surface of the outer cylinder  170  and the outer circumferential surface of the inner cylinder  172 . The projections  168  each have a substantially semicircular column shape formed by dividing a cylindrical column into two. The six projections  168  are arranged at regular intervals around the rotation axis AX of the reel  33  (along a rotation direction of the reel  33 ). In the present embodiment, adjacent projections  168  are arranged at intervals corresponding to an angle of 60 degrees around the rotation axis AX of the reel  33 . 
     The six projections  168  comprise three short projections  180  and three long projections  182 . A length of the long projections  182  in their longitudinal direction is greater than a length of the short projections  180  in their longitudinal direction. The long projections  182  extend farther away from the outer surface (right surface) of the right flange  166  than the short projections  180  do. Starting from one projection  168  (which is termed a reference projection  168   a ) among the six projections  168 , the three short projections  180  are arranged at a position of 0 degree, at a position of 120 degrees, and at a position of 180 degrees along the rotation direction of the reel  33 . Further, starting from the reference projection  168   a , the three long projections  182  are arranged at a position of 60 degrees, at a position of 240 degrees, and a position of 300 degrees along the rotation axis of the reel  33 . 
     The number of the short projections  180 , the number of the long projections  182 , and the arrangement of the short projections  180  and the long projections  182  vary depending on types of reels  33 . For example, in a reel  33  of another type, the six projections  168  comprise two short projections  180  and four long projections  182 . Starting from the reference projection  168   a , the two short projections  180  are arranged at the position of 0 degree and at the position of 180 degrees, and the four long projections  182  are arranged at the position of 60 degrees, at the position of 120 degrees, at the position of 240 degrees, and at the position of 300 degrees. 
     As shown in  FIG.  18   , the reel holder  10  further comprises a reel attaching part  186  for attaching the reel  33  such that the reel  33  is rotatable with respect to the reel holder  10 . The reel attaching part  186  comprises a left reel attaching part  188  and a right reel attaching part  190 . 
     The left reel attaching part  188  is attached to the main cover  28 . The left reel attaching part  188  comprises a stopper  192 , a cap  194 , and a compression spring  196 . The stopper  192  has a cylindrical shape and includes a bottom wall  192   a  at its right end. An insertion opening  28   a  is defined in the main cover  28  and the stopper  192  is inserted in the insertion opening  28   a  from the left. The stopper  192  comprises a flange  192   b  disposed at a left end of the stopper  192 . The flange  192   b  can contact the main cover  28  from the left. Thereby, the stopper  192  is suppressed from falling out from the insertion opening  28   a  from the left toward the right. The cap  194  is fixed to a left surface of the main cover  28 . The cap  194  suppresses the stopper  192  from falling out of the insertion opening  28   a  from the right toward the left. One end of the compression spring  196  is fixed to the cap  194  and the other end of the compression spring  196  is in contact with the bottom wall  192   a  of the stopper  192 . When the main cover  28  is in the closed state with respect to the holder housing  26  and the reel  33  is in the housing space  26   b , the compression spring  196  biases the stopper  192  toward the shaft receiving groove  172   b  defined in the inner cylinder  172  of the bobbin  160 . The stopper  192  is received by the shaft receiving groove  172   b  and supports the inner cylinder  172  such that the inner cylinder  172  is slidable. 
     The right reel attaching part  190  comprises a turntable  198 , bearings  200 ,  202 , and a ring member  204 . 
     An insertion opening  26   d  is defined in a right surface of the holder housing  26  and the turntable  198  is inserted in the insertion opening  26   d . In the insertion opening  26   d , the turntable  198  is spaced from the holder housing  26 . The turntable  198  is rotatable about a rotation axis extending in the right-left direction. The rotation axis of the turntable  198  is coincident with the rotation axis AX of the reel  33 . The turntable  198  comprises a turntable body  206 , an engagement member  208 , and a shaft  210 . The turntable body  206  has a substantially circular disk shape. As shown in  FIG.  20   , the turntable body  206  comprises a plurality of receivers  206   a  (six receivers  206   a  in the present embodiment). The number of the receivers  206   a  is equal to the number of the projections  168 . The receivers  206   a  are circular in cross section. The receivers  206   a  penetrate the turntable body  206  in its thickness direction. The six receivers  206   a  are arranged at regular intervals around the rotation axis AX of the reel  33  (along the rotation direction of the reel  33 ). In the present embodiment, adjacent receivers  206   a  are arranged at intervals corresponding to an angle of 60 degrees around the rotation axis AX of the reel  33 . 
     The engagement member  208  has a substantially cylindrical shape. The engagement member  208  extends leftward from a left surface of the turntable body  206 . The engagement member  208  includes an engagement wall  208   a  around its outer circumferential surface. As shown in  FIG.  18   , when the reel  33  is in the housing space  26   b , the engagement member  208  is inserted in the inner cylinder  172  of the bobbin  160  from the right. In this state, the engagement wall  208   a  (see  FIG.  20   ) is engaged with the engagement groove  172   a  of the inner cylinder  172 . The reel  33  is thus fixed to the turntable  198 . 
     The shaft  210  extends rightward from a right surface of the turntable body  206 . The shaft  210  has a substantially cylindrical shape. 
     The ring member  204  is disposed in the auxiliary space  30   a . The ring member  204  surrounds an outer circumferential surface of the shaft  210  in its circumferential direction. The ring member  204  supports the shaft  210  via the bearings  200 ,  202  such that the shaft  210  is rotatable. As shown in  FIG.  21   , the ring member  204  includes two screw holes  204   a . The ring member  204  is fixed to the auxiliary cover  30  (see  FIG.  18   ) by screws (not shown) being screwed in the screw holes  204   a . Thus, the turntable  198  is rotatably supported by the auxiliary cover  30  via the ring member  204  and the bearings  200 ,  202 . 
     Next, the type detecting mechanism  158  will be described. As shown in  FIG.  21   , the type detecting mechanism  158  comprises a type detecting unit  216  and a rotation detecting unit  218 . The type detecting unit  216  comprises a type detecting device  220  and a plurality of type-detecting magnetic sensors  222  (two type-detecting magnetic sensors  222  in the present embodiment) (see  FIG.  25   ). 
     As shown in  FIG.  22   , the type detecting device  220  is fixed to the turntable  198 . The type detecting device  220  comprises a cover member  226 , a plurality of support members  228  (six support members  228  in the present embodiment), a plurality of movable members  230  (six movable members  230  in the present embodiment), a plurality of type-detecting magnets  232  (six type-detecting magnets  232  in the present embodiment), and a plurality of compression springs  234  (six compression springs  234  in the present embodiment). 
     As shown in  FIG.  23   , the cover member  226  comprises a base  238  and a plurality of holding members  240  (six holding members  240  in the present embodiment). The base  238  has a circular disk shape and includes an opening at the center. The central axis of the base  238  is coincident with the rotation axis AX of the reel  33 . The six holding members  240  extend leftward from a left surface of the base  238 . The holding members  240  each comprise a pair of holding walls  240   a ,  240   b  opposing each other. The six holding members  240  are arranged at regular intervals around the rotation axis AX of the reel  33  (along the rotation direction of the reel  33 ). In the present embodiment, adjacent holding members  240  are arranged at intervals corresponding to an angle of 60 degrees around the rotation axis AX of the reel  33 . 
     As shown in  FIG.  24    the six support members  228  are integral with the turntable  198 . The six support members  228  extend rightward from the right surface of the turntable body  206 . The support members  228  are disposed at peripheral edges of the receivers  206   a  (see  FIG.  20   ) of the turntable body  206 . The support members  228  have a cylindrical shape that is partially interrupted in the circumferential direction. The support members  228  each comprise a notch  228   a  corresponding to the partial interruption in the circumferential direction and an inner projection  228   b  opposing the notch  228   a . The notches  228   a  are disposed outward of the inner projections  228   b  in a radial direction of the turntable body  206 . The six support members  228  are arranged to surround the ring member  204 . The six support members  228  are arranged at regular intervals around the rotation axis AX of the reel  33  (along the rotation direction of the reel  33 ). In the present embodiment, adjacent support members  228  are arranged at intervals corresponding to an angle of 60 degrees around the rotation axis AX of the reel  33 . 
     The movable members  230  shown in  FIG.  23    are supported by the support members  228  such that the movable members  230  are slidable in the right-left direction. The movable members  230  are disposed within the support members  228 . The movable members  230  each have a substantially cylindrical shape and include a bottom wall  230   a  at its left end. The movable members  230  each include a receiver groove  230   b  extending from its right end toward the bottom wall  230   a  and a fixture groove  230   c . The receiver groove  230   b  and the fixture groove  230   c  are arranged at intervals corresponding to an angle of 180 degrees in a circumferential direction of an outer circumferential surface of each movable member  230 . The receiver grooves  230   b  receive the inner projections  228   b  (see  FIG.  24   ) of the support members  228 . Thus, the movable members  230  are suppressed from rotating. The type-detecting magnets  232  are fitted in the fixture grooves  230   c . Thus, the type-detecting magnets  232  are fixed to the movable members  230 . 
     Each compression spring  234  is disposed between the pair of holding walls  240   a ,  240   b  of its corresponding holding member  240 . One end of each compression spring  234  is in contact with the base  238  and the other end thereof is in contact with the bottom wall  230   a  of its corresponding movable member  230 . The compression springs  234  bias the movable members  230  in a direction away from the base  238  toward an initial position. Thus, the movable members  230  are slidable between the initial position and a specific position. Here, the initial position means the position of the movable members  230  in the state where the reel  33  is not attached in the reel holder  10 . 
     As shown in  FIG.  25   , the type-detecting magnetic sensors  222  are fixed to sensor substrates  244 , respectively. The sensor substrates  244  face the type detecting device  220 . The type-detecting magnetic sensors  222  are electrically connected to the control circuit board  36  (see  FIG.  3   ) via wires which are not shown. 
     The rotation detecting unit  218  comprises a plurality of rotation-detecting magnetic sensors  248  (two rotation-detecting magnetic sensors  248  in the present embodiment). The rotation-detecting magnetic sensors  248  are fixed to the sensor substrate  244 , respectively. Each rotation-detecting magnetic sensor  248  is aligned with corresponding type-detecting magnetic sensor  222  in a direction along the rotation axis AX of the reel  33 . Hereinafter, the combination of a sensor substrate  244 , a type-detecting magnetic sensor  222 , and a rotation-detecting magnetic sensor  248  may be termed a detector  250 . In the present embodiment, the type detecting mechanism  158  comprises a plurality of detectors  250  (two detectors  250 ). Hereinafter, one of the detectors  250  (e.g., the front detector  250  in  FIG.  25   ) may be termed a detector  250   a , and the other detector  250  (e.g., the rear detector  250  in  FIG.  25   ) may be termed a detector  250   b.    
     As shown in  FIG.  26   , the two type-detecting magnetic sensors  222  are disposed at regular intervals along a rotation direction of the reel  33  (around the rotation axis AX of the reel  33 ). In the present embodiment, the two type-detecting magnetic sensors  222  are disposed at intervals corresponding to an angle of 180 degrees (360 degrees/two sensors) along the rotation direction of the reel  33 . The two rotation-detecting magnetic sensors  248  are also disposed at regular intervals along the rotation direction of the reel  33 . In the present embodiment, the two rotation-detecting magnetic sensors  248  are disposed at intervals corresponding to an angle of 180 degrees (360 degrees/two sensors) along the rotation direction of the reel  33 . 
     Next, a method of detecting the type of the reel  33  will be described. First, in the state where the main cover  28  (see  FIG.  18   ) of the reel holder  10  is open, the projections  168  (see  FIG.  27   ) of the reel  33  are inserted into corresponding receivers  206   a  (see  FIG.  27   ) of the turntable  198 . Thus, the projections  168  engage with the receivers  206   a . Then, the main cover  28  is closed and the lock lever  32  (see  FIG.  1   ) is pivoted to maintain the main cover  28  in the closed state. As a result, as shown in  FIG.  18   , the engagement wall  208   a  (see  FIG.  20   ) of the engagement member  208  of the turntable  198  engages with the engagement groove  172   a  and the stopper  192  is received into the shaft receiving groove  172   b  of the reel  33 . In this way, the reel  33  is attached to the reel attaching part  186  such that the reel  33  is rotatable with respect to the holder housing  26 . 
     As shown in  FIG.  27   , as the reel  33  is attached to the reel attaching part  186 , the three long projections  182  push corresponding movable members  230  to an attaching position from the initial position. In the direction along the rotation axis AX of the reel  33 , the attaching position is closer to the base  238  of the cover member  226  than the initial position is. The attaching position may vary depending on types of reels  33 . As the movable members  230  are pushed to the attaching position, the type-detecting magnets  232  are also pushed. In the state where the movable members  230  are at the attaching position, the type-detecting magnets  232  are at positions that face the rotation-detecting magnetic sensors  248  as the reel  33  rotates (see the front movable member  230  in  FIG.  27   ). Contrary to this, since the length of the short projections  180  is shorter than the length of the long projections  182 , the three short projections  180  do not contact corresponding movable members  230  even when the reel  33  is attached to the reel attaching part  186 . These movable members  230  are not pushed by the short projections  180  and thus maintained at the initial position by the biasing force of the compression springs  234 . In the state where the movable members  230  are at the initial position, the type-detecting magnets  232  are at positions that face the type-detecting magnetic sensor  222  as the reel  33  rotates (see the rear movable member  230  in  FIG.  27   ). 
     Next, the control circuit board  36  (see  FIG.  3   ) executes a type detecting process for detecting the type of the reel  33 . The control circuit board  36  executes the type detecting process in response to detecting that the main cover  28  is in the closed state via a closed state detecting sensor (not shown) attached to the holder housing  26 . The type detecting process is executed, for example, when the reel  33  is attached to the reel holder  10  of a newly purchased rebar tying tool  2  and/or when a new reel  33  is attached to the reel holder  10  in replacement of the used reel  33 . The type detecting process is different from the tying operation of tying the rebars R with the wire W. 
     When the control circuit board  36  rotates the feeding motor  50  (see  FIG.  4   ) forward (in the direction D 1  in  FIG.  4   ), the reel  33  thereby rotates. With the rotation of the reel  33 , the type detecting device  220  integrally rotates with the turntable  198 . Every time the movable members  230  at the initial position pass positions facing the type-detecting magnetic sensors  222 , the type-detecting magnetic sensors  222  detect the type-detecting magnets  232 , for example, by detecting magnetic variations. The control circuit board  36  detects that the type-detecting magnets  232  were detected. Further, every time the movable members  230  at the attaching position pass positions facing the rotation-detecting magnetic sensors  248 , the rotation-detecting magnetic sensors  248  detect the type-detecting magnets  232 , for example, by detecting magnetic variations. The control circuit board  36  detects that the type-detecting magnets  232  were detected. The control circuit board  36  detects signal charts shown in  FIG.  28    as the reel  33  rotates. In  FIG.  28   , the top signal chart depicted with a solid line is a signal chart associated with the detection by the type-detecting magnetic sensor  222  of the detector  250   a , the second signal chart from the top depicted with a solid line is a signal chart associated with the detection by the rotation-detecting magnetic sensor  248  of the detector  250   a , the third signal chart from the top depicted with a solid line is a signal chart associated with the detection by the type-detecting magnetic sensor  222  of the detector  250   b , and the fourth signal chart from the top (the bottom signal chart) depicted with a solid line is a signal chart associates with the detection by the rotation-detecting magnetic sensor  248  of the detector  250   b . In the example of  FIG.  28   , signal strength indicates “1” for when the type-detecting magnetic sensors  222  detect the type-detecting magnets  232  and when the rotation-detecting magnetic sensors  248  detect the type-detecting magnets  232 , whereas the signal strength indicates “0” for when the type-detecting magnetic sensors  222  do not detect the type-detecting magnets  232  and when the rotation-detecting magnetic sensors  248  do not detect the type-detecting magnets  232 . 
     Upon when the signal strength “1” takes place sixth times after the signal strength “1” took place for the first time in the four signal charts, the control circuit board  36  determines that the reel  33  has made a ½ turn and stops the feeding motor  50 . The control circuit board  36  determines that the feeding motor  50  stops when the number of rotations of the feeding motor  50  is decreased to or less than a predetermined number of rotations (e.g., 0). The signal strength “1” taking place six times after the signal strength “1” took place for the first time means that all of the type-detecting magnets  232  have been detected by the type-detecting magnetic sensor  222  and the rotation-detecting magnetic sensor  248  of the detector  250   a  or the type-detecting magnetic sensor  222  and the rotation-detecting magnetic sensor  248  of the detector  250   b . Then, the control circuit board  36  specifies shapes of the four signal charts detected within a time period T 1  in  FIG.  28   . The time period T 1  is a half of a time period T 2  of signal charts for when the reel  33  has rotated once. The control circuit board  36  then specifies reference signal charts that match the specified shapes of the four signal charts. Since the movable members  230  pushed to the attaching position varies depending on types of reels  33 , the shapes of the reference signal charts vary depending on types of reels  33 . The control circuit board  36  stores a plurality of reference signal charts corresponding to types of reels  33 . The control circuit board  36  specifies the type of the reel  33  based on the specified reference signal charts. Then, the control circuit board  36  sets conditions for tying the rebars R with the wire W using the rebar tying tool  2  according to the specified type of the reel  33 . Finally, the control circuit board  36  rotates the feeding motor  50  in reverse (in the direction D 2  in  FIG.  4   ) to pull back the wire W toward the reel  33 . 
     (Effects) 
     The rebar tying tool  2  comprises the reel  33  comprising the bobbin  160  and the wire W wound around the bobbin  160 , wherein the bobbin  160  comprises the long projections  182 ; the reel attaching part  186  to which the reel  33  is rotatably attached; the feeding unit  38  configured to feed the wire W from the bobbin  160  around the rebars R; the twisting unit  46  configured to twist the wire W around the rebars R; the plurality of detectors  250  configured to detect the long projections  182 ; and the support  15  supporting the reel attaching part  186 , the feeding unit  38 , the twisting unit  46 , and the plurality of detectors  250 . The plurality of detectors  250  is disposed along the rotation direction of the reel  33  and configured to detect the long projections  182  as the reel  33  rotates. 
     According to the configuration above, the plurality of detectors  250  is disposed along the rotation direction of the reel  33 , and thus the long projections  182  can be detected before the reel  33  finishes rotating once. Thus, specific information of the reel  33  can be detected before the reel  33  finishes rotating once. 
     Further, the rebar tying tool  2  comprises the reel attaching part  186  to which the reel  33  is rotatably attached, wherein the reel  33  comprises the bobbin  160  including the long projections  182  and the wire W wound around the bobbin  160 ; the feeding unit  38  configured to feed the wire W from the bobbin  160  around the rebars R; the twisting unit  46  configured to twist the wire W around the rebars R; the plurality of detectors  250  configured to detect the long projections  182 ; and the support  15  supporting the reel attaching part  186 , the feeding unit  38 , the twisting unit  46 , and the plurality of detectors  250 . The plurality of detectors  250  is disposed along the rotation direction of the reel  33  and configured to detect the long projections  182  as the reel  33  rotates. 
     The configuration above can achieve the same effects as those of the rebar tying tool above. 
     The reel  33  disclosed herein is used by being rotatably attached to the reel attaching part  186  of the rebar tying tool  2 . The reel  33  comprises the bobbin  160  comprising the long projections  182  and the wire W wound around the bobbin  160 . The rebar tying tool  2  comprises the plurality of detectors  250  disposed along the rotation direction of the reel  33 . The long projections  182  include type information that indicates the type of the reel  33 . The long projections  182  are detected by the plurality of detectors  250  as the reel  33  rotates. 
     According to the configuration above, the plurality of detectors  250  is disposed along the rotation direction of the reel  33 , and as such, after the reel  33  is attached to the reel attaching part  186  of the rebar tying tool  2 , the long projections  182  are detected before the reel  33  finishes rotating once. Thus, the configuration can cause the rebar tying tool  2  to detect specific information of the reel  33  before the reel  33  finishes rotating once. 
     Further, the reel attaching part  186  comprises the turntable  198  rotatably supported by the support  15 . The bobbin  160  is fixed to the turntable  198  when the reel  33  is attached to the reel attaching part  186 . 
     According to the configuration above, since the turntable  198  is supported by the support  15 , there is no need to attach/detach the turntable  198  to/from the support  15 . Thus, displacement of the rotation axis of the turntable  198  can be suppressed. Displacement of the rotation axis AX of the reel  33  thus can be suppressed. 
     Moreover, the rebar tying tool  2  further comprises the movable members  230  movably supported by the turntable  198 . The movable members  230  are at the initial position when the reel  33  is not attached to the reel attaching part  186 . The long projections  182  push the movable members  230  toward the attaching position when the reel  33  is attached to the reel attaching part  186 . Each of the plurality of detectors  250  is configured to detect the long projections  182  by detecting the movable members  230  at the attaching position. 
     According to the configuration above, specific information of the reel  33  can be detected with a simple configuration of detecting the position of the movable members  230 , before the reel  33  finishes rotating once. 
     Moreover, the rebar tying tool  2  further comprises the type-detecting magnets  232  fixed to the movable members  230 . Each of the plurality of detectors  250  comprises the type-detecting magnetic sensor  222  configured to detect whether the movable members  230  are at the attaching position by detecting the type-detecting magnets  232 . 
     In case of using an optical sensor, for example, a photointerrupter, the detection sensitivity of the photointerrupter may be decreased if the photointerrupter is contaminated by a foreign matter, etc. or if the photointerrupter is exposed to scattering light. According to the configuration above, the type-detecting magnetic sensors  222  detect whether the movable members  230  are at the attaching position or not, for example, by detecting magnetic variations caused by the type-detecting magnets  232 . Whether the movable members  230  are at the attaching position or not can be detected without the influence of contamination by foreign matters and scattering light, as compared to using a photointerrupter. 
     Moreover, the rebar tying tool  2  further comprises the compression springs  234  configured to bias the movable members  230  toward the initial position when the reel  33  is detached from the reel attaching part  186 . 
     According to the configuration above, the movable members  230  can be returned to the initial position when the reel  33  is detached from the reel attaching part  186 . 
     Moreover, the bobbin  160  comprises the trunk  162  around which the wire W is wound and the flange  166  disposed at one end of the trunk  162 . The long projections  182  project outward beyond the outer surface of the flange  166  along the rotation axis AX of the reel  33 . The turntable  198  comprises the receivers  206   a  configured to receive and engage with the long projections  182 . 
     According to the configuration above, the reel  33  can be fixed to the turntable  198  with a simple configuration. 
     Further, each of the plurality of detectors  250  comprises the rotation detecting unit  218  configured to detect a rotation angle of the reel  33 . 
     According to the configuration above, the detectors  250  can be used to detect not only the type of the reel  33  but also the rotation of the reel  33 . 
     Moreover, the rebar tying tool  2  further comprises the rotation-detecting magnets  232  configured to integrally rotate with the reel  33 . Each rotation detecting unit  218  comprises the rotation-detecting magnetic sensor  248  configured to detect the rotation angle of the reel  33  by detecting the rotation-detecting magnets  232 . 
     In case of using an optical sensor, for example, a photointerrupter, the detection sensitivity may be decreased if the photointerrupter is contaminated by a foreign matter, etc. or if the photointerrupter is exposed to scattering light. According to the configuration above, the rotation-detecting magnetic sensors  248  detect the rotation angle of the reel  33 , for example, by detecting magnetic variations caused by the type-detecting magnets  232 . The rotation angle of the reel  33  can be detected without the influence of contamination by foreign matters and scattering light, as compared to using a photointerrupter. 
     Further, the plurality of detectors  250  is fixed to the support  15 . 
     According to the configuration above, the position of the plurality of detectors  250  does not change even when the reel  33  rotates. Thus, the long projections  182  can be detected accurately by the plurality of detectors  250 . 
     Further, the plurality of detectors  250  comprises two detectors  250 . The detectors  250  adjacent to each other is disposed along the rotation direction at intervals corresponding to an angle of 180 degrees (360 degrees/2). 
     According to the configuration above, specific information of the reel  33  can be detected by the reel  33  rotating by the angle of 180 degrees (360 degrees/2). 
     (Correspondence Relationships) 
     The long projections  182  are examples of “detection target portion” and “projection”. The compression springs  234  is an example of “biasing member”. The rotation detecting units  218  are an example of “rotation detector”. The type-detecting magnets  232  are an example of “rotation-detecting magnet”. 
     Second Embodiment 
     Referring to the drawings, a second embodiment will be described. For the second embodiment, only differences from the first embodiment will be described, and like/same elements from the first embodiment will be labeled with like/same reference signs and description for them will be omitted. As shown in  FIG.  29   , in the second embodiment, two type-detecting magnetic sensors  222  are not disposed at regular intervals along the rotation direction of a reel  33  (see  FIG.  18   ) (around a rotation axis AX of the reel  33 ) and two rotation-detecting magnetic sensors  248  are not disposed at regular intervals along the rotation direction of the reel  33 , either. 
     The two type-detecting magnetic sensors  222  are disposed with an interval corresponding to an angle of 240 degrees therebetween along the rotation direction of the reel  33 . That is, the two type-detecting magnetic sensors  222  are disposed with an interval corresponding to an angle of 120 degrees therebetween along an opposite direction to the rotation direction of the reel  33 . The two rotation-detecting magnetic sensors  248  are disposed with an interval corresponding to an angle of 240 degrees therebetween along the rotation direction of the reel  33 . That is, the two rotation-detecting magnetic sensors  248  are disposed with an interval corresponding to an angle of 120 degrees therebetween along the opposite direction to the rotation direction of the reel  33 . 
     A method of detecting the type of the reel  33  will be described. Hereinafter, only a type detecting process will be described. Upon when the signal strength “1” takes place eight times after the signal strength “1” took place for the first time in the four signal charts shown in  FIG.  30   , a control circuit board  36  determines that the reel  33  has made a ⅔ turn and stops a feeding motor  50  (see  FIG.  4   ). The control circuit board  36  determines that the feeding motor  50  stops when the number of rotations of the feeding motor  50  is decreased to or less than a predetermined number of rotations (e.g., 0). The signal strength “1” taking place eight times after the signal strength “1” took place for the first time means that all of type-detecting magnets  232  have been detected by the type-detecting magnetic sensor  222  and the rotation-detecting magnetic sensor  248  of a detector  250   a  or the type-detecting magnetic sensor  222  and the rotation-detecting magnetic sensor  248  of a detector  250   b . Then, the control circuit board  36  specifies shapes of the four signal charts detected within a time period T 3  in  FIG.  30   . The time period T 3  is ⅔ of the time period T 2  of signal charts for when the reel  33  has rotated once. The control circuit board  36  then specifies reference signal charts that match the specified shapes of the four signal charts. Since the movable members  230  pushed to the attaching position varies depending on types of reels  33 , the shapes of the reference signal charts vary depending on types of reels  33 . The control circuit board  36  stores a plurality of reference signal charts corresponding to types of reels  33 . The control circuit board  36  specifies the type of the reel  33  based on the specified reference signal charts. Then, the control circuit board  36  sets conditions for tying the rebars R with the wire W using the rebar tying tool  2  according to the specified type of the reel  33 . Finally, the control circuit board  36  rotates the feeding motor  50  in reverse (in the direction D 2  in  FIG.  4   ) to pull hack the wire W toward the reel  33 . 
     (Effects) 
     The plurality of detectors  250  comprises two detectors  250 . The maximum interval between the detectors  250  adjacent to each other may be an interval corresponding to a specific angle (240 degrees) that is greater than 180 degrees (360 degrees/2) along the rotation direction. 
     According to the configuration above, specific information of the reel  33  can be detected by the reel  33  rotating by the specific angle (240 degrees) that is smaller than 360 degrees. 
     Third Embodiment 
     Referring to the drawings, a third embodiment will be described. For the third embodiment, only differences from the first embodiment will be described, and like/same elements from the first embodiment will be labeled with like/same reference signs and description for them will be omitted. As shown in  FIG.  31   , in the third embodiment, a type detecting mechanism  158  comprises three detectors  250 . Three type-detecting magnetic sensors  222  are disposed at regular intervals along the rotation direction of a reel  33  (see  FIG.  18   ) (around a rotation axis AX of the reel  33 ). In the present embodiment, the three type-detecting magnetic sensors  222  are disposed at intervals corresponding to an angle of 120 degrees (360 degrees/three sensors) along the rotation direction of the reel  33 . Three rotation-detecting magnetic sensors  248  are also disposed at regular intervals along the rotation direction of the reel  33 . In the present embodiment, the three rotation-detecting magnetic sensors  248  are disposed at intervals corresponding to an angle of 120 degrees (360 degrees/three sensors) along the rotation direction of the reel  33 . 
     In the third embodiment, as the reel  33  makes a ⅓ turn, all of type-detecting magnets  232  (see  FIG.  27   ) are detected by the type-detecting magnetic sensors  222  or the rotation-detecting magnetic sensors  248 . When determining that the reel  33  has made a ⅓ turn, a control circuit board  36  (see  FIG.  3   ) specifies the type of the reel  33  by using shapes of signal charts. 
     (Variants) 
     In one embodiment, the rotation detecting unit  218  may further comprise a plurality of rotation-detecting magnets. The rotation-detecting magnets may be fixed to the cover member  226  of the type detecting device  220 . In this instance, the rotation-detecting magnetic sensors  248  may be disposed at positions that face the rotation-detecting magnets as the reel  33  rotates. 
     In one embodiment, the number of the projections  168  is not limited to six but may be any number. Further, the number of the short projections  180  and the number of the long projections  182  are not limited to three but may be any numbers. 
     In one embodiment, the projections  168  may not be disposed at regular intervals around the rotation axis AX of the reel  33 . 
     In one embodiment, the number of the detectors  250  is not limited to two or three but may be four or more.