Patent Publication Number: US-2023141074-A1

Title: Pipe expanding tool

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Japanese patent application No. 2021-181036 filed on Nov. 5, 2021, the contents of which are hereby fully incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a pipe expanding tool that is configured to expand an end of a pipe. 
     BACKGROUND 
     A pipe expanding tool is configured to expand an end of a pipe made of plastic (polymeric) material, such as PEX (cross-linked polyethylene) so as to allow connection of pipes. The pipe expanding tool has a conical (tapered) wedge (also referred to as a needle) that reciprocates in an axial direction, and a plurality of jaws (also referred to as chucks) that are configured to expand the end of the pipe by moving radially outward along with forward movement of the wedge. Further, a pipe expanding tool is also known that includes a rotating mechanism for the jaws, in order to change positions of the jaws in the circumferential direction (see, e.g. U.S. Pat. No. 7,922,475). This rotating mechanism has a cam that moves integrally with a needle in an axial direction, and a crown that is operably coupled to the cam via a follower. The crown is rotated integrally with the jaws around an axis while the cam moves in the axial direction. 
     SUMMARY 
     The above-described rotating mechanism for the jaws is forced to rotate the jaws even if the jaws cannot be rotated for some reason. Therefore, excessive load may be applied to the rotating mechanism, so that the rotating mechanism may break. 
     It is accordingly a non-limiting object of the present disclosure to provide an improvement of a rotating mechanism for jaws in a pipe expanding tool for expanding an end of a pipe. 
     In one non-limiting aspect according to the present disclosure, a pipe expanding tool includes a wedge, a plurality of jaws, a spring and a first rotary member. The wedge is movable in a reciprocating manner between a first position and a second position along a first axis. The jaws are rotatable around the first axis and are movable relative to the first axis to a closed position and to an open position that is defined (located) radially outward of the closed position. The jaws are configured to move from the closed position to the open position as the wedge moves from the first position to the second position. The jaws are also configured to move from the open position to the closed position as the wedge moves from the second position to the first position. The first rotary member is engaged with the jaws such that the first rotary member is integrally rotatable with the jaws. The first rotary member is configured to be rotated only in one direction around the first axis by an elastic force (elastic energy, a restoring force) of the spring. 
     In the pipe expanding tool according to this aspect, the first rotary member is rotated by the elastic force of the spring to thereby rotate the jaws. Therefore, even if the first rotary member is forced to rotate the jaws while the jaws cannot be rotated for some reason, any force that exceeds the elastic force of the spring is not applied to the first rotary member. Therefore, possibility of damage to the first rotary member due to excessive load thereon can be effectively reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a sectional view of a pipe expanding tool according to an embodiment of this disclosure, showing a state in which a wedge is in a first position and jaws are in a closed position. 
         FIG.  2    is a partial, enlarged view of  FIG.  1   . 
         FIG.  3    is a sectional view taken along line III-III in  FIG.  2   . 
         FIG.  4    is a perspective view of the wedge, a reciprocating mechanism and a rotating mechanism for the jaws, showing the state in which the wedge is in the first position. 
         FIG.  5    is a sectional view corresponding to  FIG.  2   , showing a state in which the wedge is in a second position and the jaws are in an open position 
         FIG.  6    is a sectional view corresponding to  FIG.  3   , showing a state in which the wedge is in the second position and the jaws are in the open position. 
         FIG.  7    is a perspective view of the wedge, the reciprocating mechanism, the rotating mechanism for the jaws, and a holding sleeve, showing the state in which the wedge is in the second position. 
         FIG.  8    is a perspective view of a jaw assembly. 
         FIG.  9    is an exploded, perspective view of the rotating mechanism (except for a driven gear ring) for the jaws. 
         FIG.  10    is a perspective view of a second member of a rotary shaft. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     In one non-limiting embodiment according to the present disclosure, the first rotary member may be configured to be rotated by the elastic force of the spring, corresponding to at least a portion of a first movement phase of the wedge in which the wedge moves from the second position to the first position. According to this embodiment, after expanding an end of a pipe, the jaws rotate while returning from the open position to the closed position (i.e., while moving away from an inner peripheral surface of the expanded end of the pipe). Thus, the possibility that the jaws are affected by the inner peripheral surface of the pipe can be reduced, so that the first rotary member can smoothly rotate the jaws. 
     In addition or in the alternative to the preceding embodiment, the spring may be configured to store (accumulate) the elastic force, corresponding to at least a portion of a second movement phase of the wedge in which the wedge moves from the first position to the second position. The first rotary member may be configured to be rotated by the elastic force stored (accumulated) in the spring, corresponding to at least a portion of the first movement phase of the wedge. According to this embodiment, a phase in which the spring stores the elastic force (elastic energy, restoring force) and a phase in which the first rotary member rotates the jaws using the elastic force stored in the spring can rationally correspond to the two movement phases (the second and first movement phases) of the wedge, respectively. 
     In addition or in the alternative to the preceding embodiments, the pipe expanding tool may further include a movable member that is operably coupled to the spring and that is configured to move to thereby elastically deform the spring, corresponding to at least a portion of the second movement phase of the wedge. According to this embodiment, the movable member can efficiently cause the spring to store the elastic force. 
     In addition or in the alternative to the preceding embodiments, the pipe expanding tool may further include a second rotary member and a transmitting member. The second rotary member may be configured to be rotated in a first direction around a second axis, corresponding to at least a portion of the second movement phase of the wedge Further, the second rotary member may also be configured to be rotated in a second direction, which is opposite to the first direction around the second axis, by the elastic force of the spring, corresponding to at least a portion of the first movement phase of the wedge. The transmitting member may be operably coupled to the first rotary member and the second rotary member. The transmitting member may be configured to transmit only rotation of the second rotary member in the second direction to the first rotary member. This embodiment achieves a rational structure for rotating the jaws only while the second rotary member is rotated in the second direction by the elastic force of the spring, by utilizing the second rotary member that is rotatable in the two opposite directions (i.e., the first and second directions) around the second axis. 
     In addition or in the alternative to the preceding embodiments, the pipe expanding tool may further include a motion converting mechanism that is operably coupled to the spring and to the first rotary member. The motion converting mechanism may be configured to convert linear motion into rotation (rotary motion). The motion converting mechanism may be at least configured to be actuated by the elastic force of the spring to rotate the first rotary member, corresponding to at least a portion of the movement phase of the wedge from the second position to the first position. According to this embodiment, the first rotary member and the jaws can be efficiently rotated by utilizing the elastic force of the spring to convert linear motion into rotation. 
     In addition or in the alternative to the preceding embodiments, the motion converting mechanism may include a fixed member and a second rotary member that is operably engaged with the fixed member via a cam part. At least a portion of the second rotary member may be configured to cause the first rotary member to rotate by rotating around the second axis while moving along the second axis relative to the fixed member. According to this embodiment, a rational mechanism for converting linear motion into rotation can be achieved. 
     In addition or in the alternative to the preceding embodiments, the spring may be a coil spring. The fixed member and the second rotary member may be at least partially disposed inside the coil spring. According to this embodiment, the spring and the motion converting mechanism can be disposed within a relatively small space. 
     In addition or in the alternative to the preceding embodiments, the second rotary member may include a first part and a second part that are connected to each other. The first and second parts may be integrally rotatable around the second axis and movable relative to each other along the second axis. According to this embodiment, both the first and second parts can be integrally rotated by simply moving only one of the first and second parts along the second axis. 
     In addition or in the alternative to the preceding embodiments, the first part may be movable along the second axis relative to the fixed member and the second part. Further, the first part may be configured to elastically deform the spring by moving along the second axis, corresponding to at least a portion of the second movement phase of the wedge. According to this embodiment, the elastic force can be efficiently stored in the spring along with movement of the first part. 
     A pipe expanding tool  1  according to a non-limiting embodiment of the present disclosure is now described with reference to the drawings. The pipe expanding tool  1  is a power tool that is used to expand an end of a pipe or a tube (e.g., a pipe made of cross-linked polyethylene (PEX)) so as to allow connection of the pipe to another pipe. The pipe expanding tool  1  may also be called a PEX expansion tool. 
     First, the general structure of the pipe expanding tool  1  is described. 
     As shown in  FIG.  1   , the pipe expanding tool  1  mainly includes an L-shaped housing  10 , a jaw assembly  5  that is disposed on one end portion of the housing  10 , a motor  20  that is disposed within the housing  10 , and a wedge  3  that is disposed within the housing  10  and that is configured to be moved in a reciprocating manner (reciprocated) by the motor  20 . 
     The wedge  3  extends along a driving axis A 1  within the housing  10 . A front (distal) end portion of the wedge  3  protrudes into the jaw assembly  5  via an opening formed in the housing  10 . The jaw assembly  5  includes a plurality of jaws  51  that are disposed around the wedge  3  to be movable in a radial direction relative to the driving axis A 1 . An elongate portion of the housing  10  that extends substantially orthogonally to the driving axis A 1  includes a grip part  16  that is configured to be held by a user. A lever (also referred to as a trigger)  161  is supported by the grip part  16  and configured to be manually depressed by a user. When the motor  20  is driven in response to depressing operation of the lever  161  performed by the user, the wedge  3  is reciprocated and the jaws  51  are moved in the radial direction. An end of a pipe is expanded by radially outward movement of the jaws  51 . 
     In the following description, for the sake of convenience, the extending direction of the driving axis A 1  is defined as a front-rear direction of the pipe expanding tool  1 . In the front-rear direction, the side of the front end of the wedge  3  is defined as the front side and the opposite side is defined as the rear side of the pipe expanding tool  1 . A direction that is orthogonal to the driving axis A 1  and that corresponds to a longitudinal direction of the grip part  16  is defined as an up-down direction of the pipe expanding tool  1 . In the up-down direction, the side of a distal end (free end) of the grip part  16  is defined as a lower side, and the opposite side is defined as an upper side of the pipe expanding tool  1 . A direction that is orthogonal to the front-rear direction and the up-down direction is defined as a left-right direction of the pipe expanding tool  1 . 
     The detailed structure of the pipe expanding tool  1  is now described. 
     As shown in  FIG.  1   , the housing  10  includes a body part  11  extending in the front-rear direction along the driving axis A 1 , the grip part  16  protruding downward from a rear end portion of the body part  11 , and a controller housing part  18  connected to a lower end of the grip part  16 . 
     The jaw assembly  5  is removably coupled to a front end of the body part  11 . The body part  11  houses the wedge  3 , a reciprocating mechanism  4  for the wedge  3 , and a rotating mechanism  6  for the jaws  51 . The detailed structures of the mechanisms (components, elements) disposed within the body part  11  and the jaw assembly  5  will be described below. 
     The grip part  16  houses the motor  20 , a speed reducer  23  and a switch  163 . 
     The motor  20  is within a central portion of the grip part  16  in the up-down direction. In this embodiment, a brushless DC motor is employed as the motor  20 . An output shaft  201  of the motor  20  extends in the up-down direction. The output shaft  201  is rotatably supported at its upper and lower ends by bearings that are supported within the housing  10 . A rotational axis of the output shaft  201  extends orthogonally to the driving axis A 1 . 
     The speed reducer  23  is disposed above the motor  20  within the grip part  16 . The speed reducer  23  is operably coupled to the output shaft  201  of the motor  20 . In this embodiment, a multi-stage planetary gear reducer is employed as the speed reducer  23 . The output shaft  201  of the motor  20  functions as an input shaft of the speed reducer  23 . A driving shaft  41  is coupled to an output shaft of the speed reducer  23 . An axis A 3  of the driving shaft  41  extends in the up-down direction and orthogonally to the driving axis A 1 . The driving shaft  41  is rotationally driven around the axis A 3  at a lower speed than the output shaft  201  of the motor  20  when the motor  20  is driven. A speed reducer that includes a normal gear train may be employed as the speed reducer  23 , in place of the planetary gear reducer. 
     The switch  163  is disposed within a lower end portion of the grip part  16 . A plunger  164  of the switch  163  is directly behind the lever  161  (more specifically, directly behind a lower end portion of the lever  161 ) that is on the front side of the grip part  16 . The switch  163  is kept OFF while the lever  161  is not depressed. When the lever  161  is depressed rearward, the plunger  164  is pushed rearward by the lever  161  and turns ON the switch  163 . The switch  163  is electrically connected to the controller  27  (described below) via electric wires (not shown), and configured to output a prescribed signal to the controller  27  while the switch  163  is ON. 
     The controller  27  is disposed within the controller housing part  18 . The controller  27  is configured to control operation of the pipe expanding tool  1 . The controller  27  is configured, for example, as a microcomputer that includes a CPU, a ROM and a RAM. Alternatively, the controller  27  may be other kind of circuit. The controller  27  is configured to drive the motor  20  while the switch  163  is ON. Further, a battery mounting part  181  is provided in a lower end portion of the controller housing part  18 . The battery mounting part  181  is configured to removably receive a rechargeable battery (also referred to as a battery pack or a battery cartridge)  185 . Although not shown and described in detail, the battery mounting part  181  has an engagement structure that is configured to slidingly engage with the battery  185 , and terminals that are electrically connectable to terminals of the battery  185 . 
     The structures of the wedge  3  and the reciprocating mechanism  4  for the wedge  3  are now described in detail. 
     As shown in  FIGS.  2  to  4   , the wedge  3  is an elongate member having a conical (tapered) front portion (hereinafter referred to as a conical part  31 ). More specifically, the front portion of the wedge  3  is configured such that the diameter gradually decreases toward the front end. The wedge  3  may also be referred to as a needle or a cone. In this embodiment, a portion of the wedge  3  that extends rearward from the conical part  31  is cylindrically shaped (this portion is hereinafter referred to as a cylindrical part  32 ). The wedge  3  also has a flange part  33  that is provided rearward of the cylindrical part  32  and that protrudes radially outward of an outer peripheral surface of the cylindrical part  32 . 
     The wedge  3  is disposed within the housing  10  (the body part  11 ) such that its longitudinal axis coincides with the driving axis A 1 . The wedge  3  is held to be linearly movable relative to the housing  10  in a reciprocating manner in the front-rear direction along the driving axis A 1 . More specifically, a driven gear ring  68  is disposed within a front end portion of the body part  11 . The driven gear ring  68  includes a first ring  681  and a second ring  685 . The driven gear ring  68  is a portion of the rotating mechanism  6  for the jaws  51 , as will be described in detail below. The driven gear ring  68  is supported by a bearing  111  such that the driven gear ring  68  is rotatable around the driving axis A 1  and substantially immovable in the front-rear direction relative to the housing  10 . The wedge  3  is coaxially inserted through the driven gear ring  68  and held to be slidable in the front-rear direction relative to the driven gear ring  68 . 
     Further, a guide frame  113  substantially inhibits the wedge  3  from rotating around the driving axis A 1 . The guide frame  113  is held behind the driven gear ring  68  such that the guide frame  113  is substantially immovable relative to the housing  10  (the body part  11 ). A front half of the guide frame  113  is a tubular member and is disposed around the wedge  3 . A rear half of the guide frame  113  is formed by two protruding parts  114  that respectively extend rearward from upper and lower rear ends of the front half. A guide groove  115  is formed in each of the upper and lower protruding parts  114 . The two (upper and lower) guide grooves  115  extend forward from a rear end of the guide frame  113  directly above and directly below the driving axis A 1 , respectively. 
     A pin  36  is engaged with a rear end portion of the wedge  3 . More specifically, two protruding parts  34  protrude rearward from the flange part  33  of the wedge  3 . The protruding parts  34  are symmetrically arranged relative to the longitudinal axis of the wedge  3 . Each of the protruding parts  34  has a through hole. The through hole extends through the protruding part  34  in a direction that is orthogonal to the longitudinal axis of the wedge  3 . The pin  36  is inserted through the through holes of the protruding parts  34  and thus engaged with the wedge  3 . Two axial end portions of the pin  36  protrude radially outward of the wedge  3  from the protruding parts  34 , and are respectively arranged within the upper and lower guide grooves  115  such that the pin  36  is slidable in the front-rear direction. Thus, the pin  36  extends in the up-down direction and is movable integrally with the wedge  3  relative to the housing  10  in the front-rear direction. 
     Owing to such a holding structure, the wedge  3  is movable in the front-rear direction relative to the housing  10  (the body part  11 ) within a range in which the pin  36  can slide along the guide groove  115 , without substantially rotating around the driving axis A 1 . The wedge  3  is always biased rearward relative to the housing  10  and the jaw assembly  5  by the biasing spring  48 . More specifically, the biasing spring  48  is a compression coil spring and is disposed around (radially outside of) the wedge  3 . One end of the biasing spring  48  abuts on a rear surface of the driven gear ring  68  from the rear, and the other end of the biasing spring  48  abuts on a front surface of the flange part  33  of the wedge  3  from the front. 
     Further, a roller  37  is disposed between the two protruding parts  34  of the wedge  3  in the up-down direction around the pin  36 . The roller  37  is rotatable around an axis of the pin  36  relative to the pin  36 . A cam  45  of the reciprocating mechanism  4  is arranged directly behind the roller  37 . The roller  37  is always held in abutment (contact) with the cam  45  (a cam face  450 ) since the wedge  3  is biased rearward relative to the housing  10 . 
     As shown in  FIGS.  2  to  4   , the reciprocating mechanism  4  is operably coupled to or engaged with the motor  20  and the wedge  3 . The reciprocating mechanism  4  is configured to be driven by the motor  20  to reciprocate the wedge  3  along the driving axis A 1 . The reciprocating mechanism  4  of this embodiment includes the driving shaft  41 , the cam  45  and the biasing spring  48 . 
     The driving shaft  41  extends in the up-down direction, and is rotatably supported at its upper and lower ends by bearings  411 ,  412  that are supported within the housing  10  (the body part  11 ). As described above, the driving shaft  41  is rotationally driven by the motor  20  around the axis A 3  that extends in the up-down direction. 
     The cam  45  is a member that is configured to convert rotation into linear motion. The cam  45  is fixed around the driving shaft  41  such that the cam  45  rotates integrally with the driving shaft  41 . Specifically, the cam  45  is fixed around the driving shaft  41  between the bearings  411 ,  412  in the up-down direction. In this embodiment, the cam  45  is a plate cam (a disc cam, a radial cam), in which the distance from the rotational axis to an outer peripheral surface of the cam is not uniform. Specifically, the cam face  450  includes (i) a minimum-diameter part  451  whose distance from the rotational axis (the axis A 3 ) is minimum, (ii) a diameter-varying part  452  whose distance from the axis A 3  gradually increases as the cam  45  rotates, and (iii) a maximum-diameter part  453  whose distance from the axis A 3  is maximum. 
     As described above, the roller  37  is operably coupled to the wedge  3  and always pressed against the outer peripheral surface (the cam face  450 ) of the cam  45  by the biasing force of the biasing spring  48 . Thus, the wedge  3  reciprocates in the front-rear direction as the roller  37  rolls along the cam face  450 , while the driving shaft  41  and the cam  45  are rotationally driven in one direction (in the direction of an arrow RD in  FIG.  3   ) around the axis A 3  by the motor  20 . 
     More specifically, the wedge  3  is held in a rearmost position (hereinafter also referred to as a first position) within its movable range as shown in  FIGS.  2  and  3   , while the minimum-diameter part  451 ) is in abutment (contact) with the roller  37 . The wedge  3  moves forward from the first position, while the diameter-varying part  452  is in abutment (contact) with the roller  37 . As shown in  FIGS.  5  and  6   , when the maximum-diameter part  453  abuts on the roller  37 , the wedge  3  reaches a frontmost position (hereinafter also referred to as a second position) within its movable range. When the roller  37  passes the maximum-diameter part  453  as the cam  45  rotates, the minimum-diameter part  451  faces the roller  37 , and the wedge  3  is moved rearward from the second position to the first position by the biasing force of the biasing spring  48 . 
     Thus, in this embodiment, one cycle of reciprocating movement of the wedge  3  is defined by (i) a waiting phase in which the wedge  3  is held in the first position, (ii) a movement phase (hereinafter referred to as an forward movement phase) in which the wedge  3  moves from the first position to the second position, and (iii) a movement phase (hereinafter referred to as a backward movement phase) in which the wedge  3  moves from the second position to the first position. 
     The structure of the jaw assembly  5  is now described in detail. 
     As shown in  FIGS.  2 ,  3  and  8   , the jaw assembly  5  of this embodiment includes the jaws  51  and a cap  55 . The jaw assembly  5  may also be referred to as an expansion head. The jaws  51  may also be referred to as chucks or claws. The cap  55  may also be referred to as a collar or a jaw holder. 
     The jaws  51  have substantially the same shape and are arranged around the driving axis A 1 . In this embodiment, six jaws  51  are provided. A front end portion (a distal end portion) of each jaw  51  is substantially shaped like a fan that has a central angle of 60 degrees as viewed from the front. A projection  511  is provided on a rear end of each of the jaws  51  and protrudes radially outward. A groove  512  having a circular arc section is formed in a protruding end (outer edge) of the projection  511 . Further, the rear end of the jaw  51  has a recess  515  that is recessed forward from the rear end of the jaw  51 . 
     The cap  55  is configured to hold the jaws  51  to be rotatable around the driving axis A 1  and to be movable in the radial direction relative to the driving axis A 1 . The cap  55  is basically a cylindrical member. The cap  55  is removably connected to a front end portion of the housing  10  (the body part  11 ). In this embodiment, the cap  55  is screwed onto the front end portion of the body part  11 . Alternatively, the cap  55  may be connected to the body part  11  in a different manner. 
     An annular recess  551  is formed in the inside of the cap  55 . The jaws  51  are held by the cap  55  with their respective projections  511  within the recess  551 . The recess  551  provides a space that is large enough for the projections  511  to move in the radial direction within the recess  551 . An annular elastic member  553  is fitted in the grooves  512  of the projections  511  such that the elastic member  553  surrounds all the jaws  51 . Thus, the jaws  51  are always biased radially inward (toward the driving axis A 1  and the wedge  3 ). 
     Owing to such a structure, the jaws  51  move in the radial direction as the wedge  3  reciprocates along the driving axis A 1 . More specifically, as shown in  FIGS.  2  and  3   , when the wedge  3  is at (in) the first position (the rearmost position), the jaws  51  are closest to the driving axis A 1  in the radial direction, owing to the biasing force of the elastic member  553 . This position of the jaws  51  in the radial direction is hereinafter also referred to as a closed position. 
     When the wedge  3  moves forward from the first position to the second position, an outer peripheral surface of the conical part  31  of the wedge  3  abuts on inner peripheral surfaces of the jaws  51  halfway in the forward movement phase of the wedge  3 , and moves the jaws  51  radially outward. As shown in  FIGS.  5  and  6   , when the wedge  3  is at (in) the second position, the jaws  51  are farthest from the driving axis A 1  in the radial direction. This position of the jaws  51  in the radial direction is hereinafter also referred to as an open position. 
     Further, when the wedge  3  moves rearward from the second position to the first position, the jaws  51  are biased by the elastic member  553  to move radially inward as the wedge  3  moves rearward, and return to the closed position halfway in the backward movement phase of the wedge  3 . 
     The structure of the rotating mechanism  6  for the jaws  51  is now described in detail. 
     As shown in  FIGS.  2 ,  4  and  9   , the rotating mechanism  6  of this embodiment includes a fixed shaft  63 , a rotary shaft  60 , a biasing spring  65 , a one-way clutch  66 , a driving gear ring  67  and the driven gear ring  68 . 
     The fixed shaft  63  is supported to be substantially immovable relative to the housing  10  (the body part  11 ). The fixed shaft  63  extends along the axis A 2  parallel to the driving axis A 1 . More specifically, a rear end of the fixed shaft  63  is press-fitted into a support hole of a support plate  630 , which is fixedly supported by the body part  11 , and thus fixed. The fixed shaft  63  extends in the front-rear direction directly below the wedge  3 . Two cam grooves  631  are formed in an outer peripheral surface of the fixed shaft  63 . The cam grooves  631  are symmetrically arranged relative to the longitudinal axis of the fixed shaft  63  (the axis A 2 ). Each of the cam grooves  631  extends obliquely (spirally, helically) relative to the axial direction and the circumferential direction of the fixed shaft  63 . 
     The rotary shaft  60  is coaxial with the fixed shaft  63  and supported to be rotatable around the axis A 2  relative to the fixed shaft  63 . In this embodiment, the rotary shaft  60  includes a first member  61  and a second member  62  that are coaxial with each other and operably connected to each other. 
     The first member  61  includes a cylindrical part  611  and a flange part  615  that is formed on one axial end of the cylindrical part  611 . The first member  61  is fitted onto (around) the fixed shaft  63  with the flange part  615  on the rear side. A portion of the flange part  615  is always located directly in front of the lower end portion of the pin  36  (specifically, a portion protruding downward from the lower protruding part  34  of the wedge  3 ). Thus, a line that extends parallel to the axis A 2  (in the front-rear direction) passes through the portion of the flange part  615  and the lower end portion of the pin  36 . Further, two circular ball holding holes  612  are formed in the cylindrical part  611 . The ball holding holes  612  are symmetrically arranged relative to the axis of the first member  61 . Two balls  64  are rollably fitted and held in the ball holding holes  612 , respectively. The balls  64  are partially within the respective cam grooves  631  of the fixed shaft  63  to be rollable within the cam grooves  631 . 
     Owing to such a structure, the first member  61  is coupled to the fixed shaft  63  via the balls  64 . The first member  61  can rotate around the axis A 2  while moving in the front-rear direction relative to the housing  10  (the body part  11 ) within a range in which the balls  64  can roll along the cam grooves  631 . Thus, the fixed shaft  63  and the first member  61 , which is operably engaged with the fixed shaft  63  via the balls  64 , form a motion converting mechanism  600  that is configured to convert linear motion into rotation (rotary motion). 
     The second member  62  includes a bottomed (cup-shaped) cylindrical part  621  and a shaft part  625  protruding from a central portion of a bottom of the cylindrical part  621 . The second member  62  is supported to be rotatable relative to the housing  10  (the body part  11 ) and substantially immovable in the front-rear direction, with the cylindrical part  621  on the rear side and the shaft part  625  protruding forward. Further, the second member  62  is coupled to the first member  61  such that the second member  62  rotates integrally with the first member  61  relative to the fixed shaft  63  while allowing the first member  61  to move in the front-rear direction relative to the second member  62 . 
     More specifically, a support plate  620  with a support hole is fixedly held in front of the support plate  630  within the body part  11 . The shaft part  625  is inserted through the support hole of the support plate  620  and rotatably supported by the support plate  620 . A portion of the shaft part  625  protrudes forward of the support plate  620 . The inner diameter of the cylindrical part  621  of the second member  62  is larger than the outer diameter of the cylindrical part  611  of the first member  61 , and a portion of the cylindrical part  621  is disposed around (radially outside of) the cylindrical part  611 . Two ball guide grooves  622  are formed in an inner peripheral surface of the cylindrical part  621 . The ball guide grooves  622  are symmetrically arranged relative to the axis of the second member  62  (the axis A 2 ), and extend linearly in the axial direction (see  FIG.  10   ). The balls  64  held in the ball holding holes  612  of the cylindrical part  611  partially protrude radially outward from the cylindrical part  611  and are engaged with the ball guide grooves  622 . 
     Owing to such a structure, the second member  62  is coupled to the first member  61  via the balls  64 . When the first member  61  rotates around the axis A 2  while moving in the front-rear direction relative to the fixed shaft  63 , the second member  62  rotates integrally with the first member  61  while allowing the first member  61  to move in the front-rear direction relative to the second member  62 . 
     he biasing spring  65  is a compression coil spring. The biasing spring  65  is disposed between the support plate  620  and the first member  61  in the front-rear direction in a slightly compressed state (loaded state). More specifically, front and rear ends of the biasing spring  65  abut on a rear surface of the support plate  620  and a front surface of the flange part  615 , respectively. The biasing spring  65  biases the first member  61  away from the support plate  620  (i.e. rearward relative to the fixed shaft  63  and the second member  62 ). Therefore, in an initial state in which a forward external force is not applied to the first member  61 , the first member  61  is held in a rearmost position (hereinafter also referred to as an initial position) where a rear surface of the flange part  615  abuts on a front surface of the support plate  630 . It is preferable that the biasing spring  65  is in a slightly compressed state in the initial state, but the biasing spring  65  may be disposed between the support plate  620  and the first member  61  in a substantially non-compressed state. 
     The coil diameter of the biasing spring  65  is slightly larger than the outer diameter of the cylindrical part  621  of the second member  62 . The biasing spring  65  is disposed around (radially outside of) the cylindrical part  621 . Thus, the cylindrical part  611  of the first member  61 , the cylindrical part  621  of the second member  62  and a portion of the fixed shaft  63  are inside (radially inside) of the biasing spring  65 . Owing to such a structure, a space occupied by the fixed shaft  63 , the rotary shaft  60  and the biasing spring  65  can be relatively small, so that the relatively compact rotating mechanism  6  is achieved. 
     The one-way clutch  66  is configured to transmit rotation only in one direction and to idle in an opposite direction. The one-way clutch  66  of this embodiment is a general purpose one-way clutch, which includes a cylindrical outer ring and a plurality of rolling elements (clutch members) disposed within the outer ring. Rollers (specifically, needle rollers) are employed as the rolling elements in this embodiment. However, any one-way clutch having a structure different from this may be employed. The one-way clutch  66  is between the rotary shaft  60  and the driving gear ring  67 , and configured to transmit only rotation of the rotary shaft  60  in one prescribed direction to the driving gear ring  67 . 
     The driving gear ring  67  is an annular or ring-like (cylindrical) member having a gear. More specifically, the driving gear ring  67  includes a cylindrical part  671  and a gear teeth  675  protruding radially outward from an outer peripheral surface of the cylindrical part  671 . The outer ring of the one-way clutch  66  is press-fitted into and fixed to an inner peripheral surface of the cylindrical part  671  of the driving gear ring  67 . Further, the portion of the shaft part  625  of the second member  62  that protrudes forward of the support plate  620  is inserted through the one-way clutch  66 . 
     The driven gear ring  68  is an annular or ring-like (cylindrical) member having a gear. The driven gear ring  68  is disposed around the wedge  3  to be coaxial with the wedge  3 , as described above. The driven gear ring  68  is operably engaged with the driving gear ring  67  and the jaws  51 . The driven gear ring  68  is configured to be rotated by the driving gear ring  67  to rotate integrally with the jaws  51 . In this embodiment, the driven gear ring  68  includes a first ring  681  and a second ring  685  that are coaxially connected to each other such that the first ring  681  and the second ring  685  integrally rotate. 
     The first ring  681  is a gear ring (an annular (cylindrical) member having a gear). Specifically, the first ring  681  includes a cylindrical part  682  and a gear teeth  683  formed around a rear end of the cylindrical part  682 . The gear teeth  683  mesh (is engaged) with the gear teeth  675  of the driving gear ring  67 . 
     The second ring  685  is an annular (cylindrical) member having a flange. Specifically, the second ring  685  includes a cylindrical part  686 , a flange  687  formed around a front end of the cylindrical part  686 , and a plurality of projections  688  protruding forward from a front end of the cylindrical part  686 . The projections  688  are arranged at equal intervals in the circumferential direction. In this embodiment, the number of projections  688  is six, corresponding the number of the jaws  51 . Each of the projections  688  is configured to engage with the recess  515  formed at the rear end of the jaw  51 . The second ring  685  and the jaws  51  are connected to each other to be integrally rotatable by engagement between the projections  688  and the recesses  515  of the jaws  51 . 
     The first ring  681  and the second ring  685  are connected such that the first ring  681  and the second ring  685  rotate integrally (in one piece) as the driven gear ring  68  by engagement between teeth formed in a front end of the first ring  681  and teeth formed in a rear end of the second ring  685  (see  FIG.  4   ). The driven gear ring  68  is supported to be rotatable around the driving axis A 1  relative to the housing  10  (the body part  11 ) by the common bearing  111  that is disposed between the gear teeth  683  of the first ring  681  and the flange  687  of the second ring  685  in the front-rear direction. The bearing  111  is fixed to an inner peripheral surface of a holding sleeve  112 , which is fixedly supported within the body part  11 . The driven gear ring  68  is supported to be substantially immovable in the front-rear direction relative to the housing  10  (the body part  11 ) by the holding sleeve  112  and the guide frame  113 . 
     As described above, the driven gear ring  68  of this embodiment is formed by the two separate members (the first and second rings  681 ,  685 ) for ease of assembly, but the driven gear ring  68  may be formed as a single (inseparable) member. 
     The rotating mechanism  6  having the above-described structure rotates the jaws  51  only in one direction around the driving axis A 1  by the elastic force (elastic energy, restoring force) of the biasing spring  65 . Operation of the rotating mechanism  6  is now described. 
     When a forward external force (a pressing force) is applied to the first member  61 , the first member  61  of the rotary shaft  60  rotates in a prescribed direction around the axis A 2  while moving forward from the initial position relative to the fixed shaft  63 , while compressing (elastically deforming) the biasing spring  65 . In the meantime, the second member  62  rotates together with the first member  61  in the prescribed direction while allowing the forward movement of the first member  61 , without moving in the front-rear direction relative to the fixed shaft  63 . The direction in which the rotary shaft  60  rotates when the first member  61  moves forward relative to the fixed shaft  63  and the housing  10  is hereinafter referred to as a first direction. The first member  61  causes the biasing spring  65  to store (accumulate) an elastic force (elastic energy) (i.e., the first member  61  applies elastic load to the biasing spring  65 ) by compressing (elastically deforming) the biasing spring  65  while moving forward from the initial position. 
     The one-way clutch  66  idles relative to the shaft part  625  of the second member  62  and does not transmit rotation to the driving gear ring  67  when the rotary shaft  60  rotates in the first direction. In other words, even if the rotary shaft  60  rotates in the first direction, the driving gear ring  67  is not rotated. Thus, the driven gear ring  68  and the jaws  51  are not rotated either. 
     When the forward external force (pressing force) against the first member  61  is released after the first member  61  is moved forward from the initial position, the first member  61  is biased rearward by the elastic force (elastic energy, restoring force) stored in the biasing spring  65 . Thus, the first member  61  rotates around the axis A 2  in a second direction, which is opposite to the first direction, while moving rearward. In the meantime, the second member  62  rotates together with the first member  61  in the second direction while allowing rearward movement of the first member  61 , without moving in the front-rear direction relative to the fixed shaft  63 . In this manner, the rotary shaft  60  is rotated in the second direction by the elastic force stored in the biasing spring  65 . 
     When the rotary shaft  60  rotates in the second direction, the one-way clutch  66  is locked to the shaft part  625  of the second member  62  and rotates integrally with the rotary shaft  60 , thereby transmitting rotation to the driving gear ring  67 . In other words, the driving gear ring  67  rotates integrally with the rotary shaft  60  in the second direction. Thus, the driven gear ring  68  and the jaws  51  are rotated around the driving axis A 1  relative to the housing  10  as the driving gear ring  67  rotates. In this manner, the driven gear ring  68  and the jaws  51  are rotated in one specific direction around the driving axis A 1  only when the rotary shaft  60  is rotated in the second direction by the elastic force stored in the biasing spring  65 . 
     Further, in this embodiment, the rotating mechanism  6  is configured such that the movement of the first member  61  in the front-rear direction partly corresponds to the movement of the wedge  3  in the front-rear direction. The correspondence between operation of the reciprocating mechanism  4  and the wedge  3  and the operation of the rotating mechanism  6  is now described. 
     While the cam  45  is rotated by the motor  20  and the diameter-varying part  452  of the cam face  450  is in abutment with the roller  37 , the cam  45  moves the wedge  3  from the first position (the rearmost position) to the second position (the frontmost position) via the roller  37  and the pin  36 . As described above, in a portion (i.e., not an entirety) of this forward movement phase, the wedge  3  moves the jaws  51  from the closed position to the open position (see  FIGS.  5  and  6   ). 
     Further, corresponding to a portion of the forward movement phase of the wedge  3 , the lower end portion of the pin  36  abuts on (comes into contact with) the rear surface of the flange  615  of the first member  61  and moves the first member  61  forward. Specifically, as shown in  FIGS.  2  and  4   , when the wedge  3  is at the first position, the lower end portion of the pin  36  is spaced apart rearward from the first member  61  located at the initial position. This position of the pin  36  in the front-rear direction is hereinafter referred to as a separate position. When the wedge  3  moves a prescribed distance forward from the first position in the forward movement phase, the lower end portion of the pin  36  abuts on the rear surface of the flange  615  from the rear. This position of the pin  36  in the front-rear direction is hereinafter referred to as an abutting position. Thereafter, as shown in  FIGS.  5  and  7   , as the wedge  3  moves forward to the second position, the pin  36  moves the first member  61  forward while moving forward from the abutting position. In the meantime, as described above, the rotary shaft  60  rotates in the first direction and thus the one-way clutch  66  is not actuated, so that the jaws  51  are not rotated. 
     When the cam  45  is further rotated by the motor  20  and the roller  37  passes the maximum-diameter part  453  of the cam face  450 , the minimum-diameter part  451  faces the roller  37 , so that the wedge  3  moves rearward from the second position to the first position. As described above, in a portion of this backward movement phase of the wedge  3 , the jaws  51  move from the open position to the closed position (see  FIGS.  2  and  3   ). 
     Further, corresponding to a portion of the backward movement phase of the wedge  3 , the first member  61  is moved rearward by the elastic force of the biasing spring  65 . Specifically, the forward pressing force of the lower end portion of the pin  3  applied to the first member  61  is released substantially simultaneously when the minimum-diameter part  451  faces the roller  37 . Therefore, the first member  61  is rotated in the second direction while being moved rearward by the elastic force stored in the biasing spring  65 , and thus the second member  62  is also rotated in the second direction. Thus, as described above, the one-way clutch  66  is actuated, and the jaws  51  are rotated via the driving gear ring  67  and the driven gear ring  68 . 
     An angle by which the jaws  51  are rotated (a rotation angle of the jaws  51 ) while the first member  61  moves rearward along the cam grooves  631  is indirectly defined by the cam grooves  631 . More specifically, the rotation angle of the driving gear ring  67  is directly defined by the cam grooves  631 . The driving gear ring  67  and the driven gear ring  68  form a speed reducing mechanism, so that the rotation angles of the driven gear ring  68  and the jaws  51  become smaller than the rotation angle of the driving gear ring  67  according to the gear ratio of the speed reducing mechanism. 
     Thus, in this embodiment, the rotary shaft  60  and thus the driven gear ring  68  and the jaws  51  are rotated in the second direction, not by the force applied by the cam  45  and the pin  36 , but by the elastic force of the biasing spring  65 . Further, in the backward movement phase of the wedge  3 , the rearward movement of the wedge  3  is simply caused by the elastic force of the biasing spring  48 , although the rearward movement of the wedge  3  is synchronized with the rotation of the cam  45 . The rotation of the driven gear ring  68  and the jaws  51  is caused in a portion of the backward movement phase of the wedge  3 , but not mechanically interlocked with the rearward movement of the wedge  3 . 
     As described above, in the pipe expanding tool  1  of this embodiment, the rotating mechanism  6  includes the driven gear ring  68  that is rotated by the elastic force (elastic energy, restoring force) of the biasing spring  65 , and causes the jaws  51  to rotate via the driven gear ring  68 . Therefore, even if the driven gear ring  68  is forced to rotate the jaws  51  while the jaws  51  cannot be rotated for some reason, any force that exceeds the elastic force of the biasing spring  65  is not applied to the driven gear ring  68  and other members of the rotating mechanism  6 . This effectively reduces the possibility of damage to the rotating mechanism  6  due to excessive load thereon. Further, a mechanical clutch mechanism may be employed as a countermeasure when the jaws  51  cannot be rotated for some reason. However, in such a mechanical clutch mechanism, torque for interrupting transmission needs to be strictly adjusted. On the contrary, the rotating mechanism  6  of this embodiment does not require such troublesome adjustment. 
     In this embodiment, the rotating mechanism  6  rotates the jaws  51 , corresponding to a portion of the backward movement phase of the wedge  3  in which the wedge  3  moves from the second position to the first position. Therefore, after expanding an end of a pipe, the jaws  51  rotate while returning from the open position to the closed position (i.e., while moving away from an inner peripheral surface of the expanded pipe). Thus, the possibility that the jaws  51  are affected by the inner peripheral surface of the pipe can be reduced, so that the rotating mechanism  6  can smoothly rotate the jaws  51 . 
     In this embodiment, the rotating mechanism  6  causes the biasing spring  65  to store the elastic force, corresponding to a portion of the forward movement phase of the wedge  3  in which the wedge  3  moves from the first position to the second position. Further, the rotating mechanism  6  rotates the jaws  51  by the elastic force stored in the biasing spring  65 , corresponding to a portion of the backward movement phase of the wedge  3  in which the wedge  3  moves from the second position to the first position. Thus, the phase of storing the elastic force in the biasing spring  65  and the phase of rotating the jaws  51  by the elastic force stored in the biasing spring  65  rationally correspond to the two different movement phases of the wedge  3 , respectively. 
     In this embodiment, the first member  61  elastically deforms the biasing spring  65  by moving, corresponding to a portion of the forward movement phase of the wedge  3 , thereby efficiently causing the biasing spring  65  to store the elastic force. Particularly, the pin  36 , which is linearly moved by the power of the motor  20 , is utilized to move the first member  61  forward. The pin  36  also serves to move the wedge  3  forward. Thus, the structure for moving the first member  61  is achieved without increasing the number of parts (parts count). 
     Further, in this embodiment, the rotary shaft  60  rotates in the first direction, corresponding to a portion of the forward movement phase of the wedge  3 , and rotates in the second direction, corresponding to a portion of the backward movement phase of the wedge  3 . The one-way clutch  66  disposed between the rotary shaft  60  and the driving gear ring  67  transmits to the jaws  51  only the rotation of the rotary shaft  60  in the second direction and does not transmit the rotation of the rotary shaft  60  in the first direction. Thus, while utilizing the rotary shaft  60  that is rotatable in two opposite directions (i.e., the first and second directions) around the axis A 2 , the one-way clutch  66  can achieve the rotating mechanism  6  with a rational structure that rotates the jaws  51  only while the rotary shaft  60  rotates in the second direction by the elastic force of the biasing spring  65 , corresponding to a portion of the backward movement phase. 
     In this embodiment, the fixed shaft  63  and the rotary shaft  60  (specifically, the first member  61 ) that is operably engaged with the fixed shaft  63  via the balls  64  form the motion converting mechanism  600  that converts linear motion into rotation. The motion converting mechanism  600  is actuated by the elastic force of the biasing spring  65  to cause the driven gear ring  68  and the jaws  51  to rotate, corresponding to at least a portion of the backward movement phase of the wedge  3 . Thus, the jaws  51  are efficiently rotated by the elastic force of the biasing spring  65  by utilizing the motion converting mechanism  600 . Particularly, in this embodiment, linear motion of the first member  61  is converted into rotation of the first member  61 , so that the motion converting mechanism  600  is compact in the axial direction. 
     In this embodiment, the rotary shaft  60  includes the first member  61  and the second member  62  that are coupled to each other such that the first member  61  and the second member  62  are integrally rotatable around the axis A 2  and are movable relative to each other in the extending direction of the axis A 2  (i.e., in the front-rear direction). Owing to this structure, both the first member  61  and the second member  62  can be integrally rotated by simply moving only the first member  61  in the front-rear direction without moving the second member  62 . Therefore, the second member  62  can rotate the driven gear ring  68  in a stable state via the driving gear ring  67 . 
     The first member  61  not only causes the driven gear ring  68  and the jaws  51  to rotate by being rotated by the elastic force of the biasing spring  65 , corresponding to a portion of the backward movement phase of the wedge  3 , but also elastically deforms the biasing spring  65  by moving in the front-rear direction, corresponding to a portion of the forward movement phase of the wedge  3 . Thus, the first member  61  with multiple functions achieves the rational rotating mechanism  6  that can cause the biasing spring  65  to store the elastic force and that can rotate the driven gear ring  68  and the jaws  51  by the stored elastic force. 
     Correspondences between the features of the above-described embodiment and the features of the present disclosure are as follows. The features of the above-described embodiment are merely exemplary and do not limit the features of the present disclosure. 
     The pipe expanding tool  1  is an example of a “pipe expanding tool”. The wedge  3  is an example of a “wedge”. The driving axis A 1  is an example of a “first axis”. The first (rearmost) position and the second (frontmost) position of the wedge  3  are examples of a “first position” and a “second position”, respectively. The jaw  51  is an example of a “jaw”. The closed position and the open position of the jaws  51  are examples of a “closed position” and a “open position”, respectively. The biasing spring  65  is an example of a “spring”. The driven gear ring  68  is an example of a “first rotary member”. The backward movement phase of the wedge  3  is an example of a “first movement phase of the wedge in which the wedge moves from the second position to the first position”. The forward movement phase of the wedge  3  is an example of a “second movement phase of the wedge in which the wedge moves from the first position to the second position”. 
     The first member  61  is an example of a “movable member”. The rotary shaft  60  is an example of a “second rotary member”. Each of the first member  61  and the second member  62  is also an example of the “second rotary member”. The one-way clutch  66  is an example of a “transmitting member”. The motion converting mechanism  600  is an example of a “motion converting mechanism”. The fixed shaft  63  is an example of a “fixed member”. The balls  64  and the cam grooves  631  are examples of a “cam part”. The first member  61  and the second member  62  of the rotary shaft  60  are examples of a “first part of the second rotary member” and a “second part of the second rotary member”, respectively. 
     The above-described embodiment is a mere example and a pipe expanding tool according to the present disclosure is not limited to the pipe expanding tool  1  of the above-described embodiment. For example, the following non-limiting modifications may be made. At least one of these modifications may be employed in combination with at least one of the features of the pipe expanding tool  1  or at least one of the claimed features. 
     For example, the wedge  3  need not be driven by the motor  20 . Similarly, in the rotating mechanism  6  for the jaws  51 , the power for elastically deforming the biasing spring  65  is not limited to the power of the motor  20 . Thus, the pipe expanding tool  1  need not include the motor  20 . Instead, the pipe expanding tool may include a mechanism that is configured to move the wedge  3  forward and a mechanism that is configured to move the first member  61  in response to manual operation performed by a user. In another modification, a motor with a brush or an AC motor may be employed, in place of the brushless DC motor. 
     In the above-described embodiment, the pin  36 , which is driven by the motor  20 , has the function of moving the wedge  3  forward and the function of moving the first member  61  forward. Alternatively, a member that is configured to move the wedge  3  forward may be a different member from a member that is configured to abut on the first member  61  to move it forward. The shapes of these members and manners of connection, engagement and/or action between these members and the motor  20 , the wedge  3  and the first member  61  may be appropriately changed. 
     The correspondence between the rearward movement of the wedge  3  and the rearward movement of the first member  61  caused by the elastic force of the biasing member  65  may be appropriately changed. In other words, the driven gear ring  68  and the jaws  51  may be rotated, corresponding to a different portion or an entirety of the backward movement phase of the wedge  3 . For example, the first member  61  may be rotated while being moved rearward by the elastic force of the biasing member  65 , corresponding to the middle or the latter half of the backward movement phase of the wedge  3 , or the entirety of the backward movement phase of the wedge  3 . 
     It may be sufficient for the reciprocating mechanism  4  for the wedge  3  to be configured to cause the wedge  3  to reciprocate. For example, a known crank mechanism including a crank shaft may be employed. Further, any kind of face (plane) cam (e.g., a face grooved cam) or a solid cam (e.g., a cylindrical grooved cam, a barrel cam) may be employed in place of a plate cam as the cam  45 . 
     The structure of the jaw assembly  5  may be appropriately changed. For example, the shape and number of the jaws  51  and the manner in which the cap  55  holds the jaws  51  may be arbitrarily selected. Further, in order to allow replacement of the jaws  51  according to the kind of a pipe, like in this embodiment, it is preferable that the jaws  51  are part of the jaw assembly  5  that is removable from the housing  10 . 
     Any modification may be made to the rotating mechanism  6 , as far as it includes at least a spring and a rotary member that is engaged with the jaws such that the rotary member is integrally rotatable with the jaws and is configured to be rotated only in one direction around the driving axis A 1  by the elastic force of the spring. 
     For example, in place of the biasing spring  65  (compression coil spring), any kind of spring (e.g., a tension spring, a torsion spring, a disc spring and a spiral spring) may be employed. Further, the movable member that acts on the spring to elastically deform (load) the spring and cause the spring to store (accumulate) the elastic force (elastic energy) is not limited to the first member  61 . For example, the movable member may be a member that is configured to be driven and moved independently from the motion converting mechanism  600  by a motor or in response to manual operation by a user. 
     A motion converting mechanism having a different structure from the motion converting mechanism  600  of the above-described embodiment may be employed. For example, the motion converting mechanism may utilize a cam part of a different type (e.g., an inclined surface that is inclined relative to the extending direction of the axis A 2  and the circumferential direction), in place of the balls  64  and the cam grooves  631 . 
     In the above-described embodiment, the rotary shaft  60  that is rotatable in the two opposite directions (the first and second directions) around the axis A 2  and the one-way clutch  66  are utilized to rotate the driven gear ring  68  only in one direction. Instead, the driven gear ring  68  may be rotated, for example, by a rotary member that does not rotate while the spring elastically deforms, corresponding to at least a portion of the forward movement phase of the wedge  3 , but is rotated by the elastic force of the spring, corresponding to at least a portion of the backward movement phase or the waiting phase of the wedge  3 . 
     Further, in view of the nature of the present disclosure and the above-described embodiment, the following aspects can be provided. At least one of the following aspects can be employed in combination with at least one of the pipe expanding tool  1  of the above-described embodiment and its modifications or the claimed features. 
     (Aspect 1) 
     The pipe expanding tool further comprises: 
     a housing that defines the first axis; and 
     a motor that is housed within the housing, 
     wherein the wedge is configured to be driven by the motor to be reciprocated. 
     According to this aspect, an efficient pipe expanding tool with the motor is provided. The housing  10  (the body part  11 ) and the motor  20  are examples of a “housing” and a “motor”, respectively, in this aspect. 
     (Aspect 2) 
     The pipe expanding tool further comprises a cam that is operably coupled to the motor and configured to be rotationally driven by the motor to reciprocate the wedge along the first axis. 
     According to this aspect, rotation of the motor can be converted into linear motion to reciprocate the wedge with a simple structure. The cam  45  is an example of a “cam” in this aspect. 
     (Aspect 3) 
     The movable member is configured to be moved by power of the motor. 
     According to this aspect, an efficient structure is provided in which the motor moves the wedge and the movable member. 
     (Aspect 4) 
     The pipe expanding tool further comprises an abutting member that is configured to selectively come into contact with the movable member and move the movable member, corresponding to at least a portion of the second movement phase of the wedge. 
     According to this aspect, by utilizing the abutting member that is driven by the motor, the elastic force can be efficiently stored in the spring, corresponding to at least a portion of the second movement phase of the wedge in which the wedge moves from the first position to the second position. The pin  36  is an example of an “abutting member” in this aspect. 
     (Aspect 5) 
     The motion converting mechanism is configured to be selectively actuated by the motor, corresponding to at least a portion of the second movement phase of the wedge. 
     According to this aspect, a rational structure is provided that can convert linear motion into rotation by power of the motor in the second movement phase of the wedge, and that can convert linear motion into rotation by the elastic force of the spring in the first movement phase of the wedge. 
     (Aspect 6) 
     The movable member is included in the motion converting mechanism and is configured to elastically deform the spring by linearly moving along the second axis while rotating around the second axis. 
     According to this aspect, the movable member provides a function of elastically deforming the spring while operating as a portion of the motion converting mechanism, so that an efficient mechanism is provided without increasing the number of parts. 
     (Aspect 7) 
     The second rotary member also serves as the movable member. 
     (Aspect 8) 
     The pipe expanding tool further comprises: 
     a housing that defines the first axis; and 
     a cap that is removably coupled to the housing and holds the jaws to be movable between the closed position and the open position and to be rotatable around the first axis, 
     wherein the jaws and the cap form a jaw assembly. 
     The cap  55  and the jaw assembly  5  are examples of a “cap” and a “jaw assembly”, respectively, in this aspect. 
     (Aspect 9) 
     The jaws are biased toward the closed position by an elastic member, and the wedge is configured to move in abutment with the jaws to thereby move the jaws from the closed position to the open position in at least a portion of the second movement phase. 
     (Aspect 10) 
     The pipe expanding tool further comprises: 
     a third rotary member that is operably coupled to the transmitting member and the first rotary member, 
     wherein the first rotary member and the third rotary member are gear rings that mesh with each other. 
     The driving gear ring  67  is an example of a “third rotary member” in this aspect. 
     (Aspect 11) 
     The transmitting member comprises a one-way clutch. 
     According to this aspect, a simple and rational structure for rotating the first rotary member only in one direction is achieved by a common, general-purpose one-way clutch. 
     (Aspect 12) 
     The cam part includes: 
     a cam groove that is formed in a first one of the fixed member and the second rotary member and that extends obliquely or helically (spirally) around the second axis, and 
     a follower that is engaged with the cam groove and operably coupled to a second one of the fixed member and the second rotary member. 
     The cam groove  631  and the ball  64  are examples of a “cam groove” and a “follower”, respectively, in this aspect. 
     (Aspect 13) 
     The first part of the second rotary member is operably engaged with the fixed member via the cam part. 
     (Aspect 14) 
     The fixed member is a shaft extending along the second axis, and the second rotary member is at least partially arranged around the fixed member. 
     (Aspect 15) 
     The first axis and the second axis extend in parallel and are spaced apart from each other. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
       1 : pipe expanding tool,  10 : housing,  11 : body part,  111 : bearing,  112 : holding sleeve,  113 : guide frame,  114 : protruding part,  115 : guide groove,  16 : grip part,  161 : lever,  163 : switch,  164 : plunger,  18 : controller housing part,  181 : battery mounting part,  185 : battery,  20 : motor,  201 : output shaft,  23 : speed reducer,  27 : controller,  3 : wedge,  31 : conical part,  32 : cylindrical part,  33 : flange part,  34 : protruding part,  36 : pin,  37 : roller,  4 : reciprocating mechanism,  41 : driving shaft,  411 : bearing,  412 : bearing,  45 : cam,  450 : cam face,  451 : minimum-diameter part,  452 : diameter-varying part,  453 : maximum-diameter part,  48 : biasing spring,  5 : jaw assembly,  51 : jaw,  511 : projection,  512 : groove,  515 : recess,  55 : cap,  551 : recess,  553 : elastic member,  6 : rotating mechanism,  600 : motion converting mechanism,  60 : rotary shaft,  61 : first member,  611 : cylindrical part,  612 : ball holding hole,  615 : flange part,  62 : second member,  620 : support plate,  621 : cylindrical part,  622 : ball guide groove,  625 : shaft part,  63 : fixed shaft,  630 : support plate,  631 : cam groove,  64 : ball,  65 : biasing spring,  66 : one-way clutch,  67 : driving gear ring,  671 : cylindrical part,  675 : gear teeth,  68 : driven gear ring,  681 : first ring,  682 : cylindrical part,  683 : gear teeth,  685 : second ring,  686 : cylindrical part,  687 : flange,  688 : projection, A 1 : driving axis, A 2 : axis, A 3 : axis