Abstract:
A replacement device of a processing apparatus includes a gripping device having a single first support member positionally fixed, a first gripping portion provided on the first support member to grip a holder not to rotate in a releasing direction when the processing member is removed from the holder, and a second gripping portion provided on the first support member apart from the first gripping portion to grip the holder not to rotate in a restricting direction when the processing member is attached to the holder, and a holding device having a single movable second support member, plural first holding portions provided on the second support member to respectively accommodate the processing member removed from the holder, and plural second holding portions provided on the second support member apart from the first holding portions to respectively accommodate the processing member that is to be attached to the holder.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a processing apparatus, and more particularly relates to a processing apparatus including a replacement device that can freely and automatically replace a processing member. 
         [0002]    In recent years, in addition to general arc welding and the like, there has been proposed a friction stir welding apparatus that performs friction stir on a predetermined weld portion in a processing target component formed from a plurality of metal plates such as aluminum plates by using a probe rotating at a high speed, and that welds the metal plates to each other. A configuration including a weld portion welded by the friction stir welding apparatus has been realized even in strength components of a mobile object such as an automobile. 
         [0003]    In such a friction stir welding apparatus, it is necessary to move the probe and the processing target component relatively to each other, and precisely weld the predetermined weld portion. Therefore, in a case where some material of the processing target component sticks onto and smears the probe or where the probe is worn down, it is desirable to realize a configuration in which the probe can be replaced simply. Furthermore, other processing apparatuses including a processing member such as a probe have the same circumstances as described above. 
         [0004]    Under the circumstances, Japanese Patent Application Laid-open Publication No. 2006-116644 relates to an automatic perforating apparatus, and discloses a configuration in which a collet chuck  3  is provided at a distal end of a spindle  1 , and an inner diameter of the collet chuck  3  is automatically increased or decreased, thereby replacing a rotary tool  8  in an unmanned manner. 
         [0005]    Further, Japanese Patent Application Laid-open Publication No. 2007-7781 relates to an automatic tool exchanger, and discloses a configuration in which the automatic tool exchanger includes a tool chucking unit  41  and a tool unchucking unit  51  that are provided so as to be advanceable and retractable between a tool storage device  31  and a tool exchanging position P 2 , thereby exchanging tools to a spindle including a tool chucking mechanism  24 . 
       SUMMARY OF THE INVENTION 
       [0006]    However, according to the studies by the present inventors, Japanese Patent Application Laid-open Publication No. 2006-116644 has a configuration in which, in a state where any one of a plurality of holding notches  18  provided on a tool magazine  4  is advanced to a position immediately below the collet chuck  3 , and where a spindle head  2  is lowered, a locking protruding portion  25  provided on an upper surface of the tool magazine  4  is engaged with a locking recessed portion  17  formed on a lower-end outer-peripheral surface of an outer cylinder  6  of the collet chuck  3 , and in a state where the outer cylinder  6  is stopped from rotating, the spindle  1  is rotated to increase or decrease the inner diameter of the collet chuck  3 . Therefore, it is necessary to precisely align the locking protruding portion  25  provided on the upper surface of the tool magazine  4  with the locking recessed portion  17  formed on the lower-end outer-peripheral surface of the outer cylinder  6  of the collet chuck  3  to engage them with each other. Accordingly, such a configuration is complicated. Furthermore, it is necessary to provide the locking protruding portion  25  for each of the holding notches  18  on the tool magazine  4 . Therefore, such a configuration is more complicated. Accordingly, both of these configurations have a room for improvement. 
         [0007]    Further, according to the studies by the present inventors, in Japanese Patent Application Laid-open Publication No. 2007-7781, at the time of a tool-unchucking operation, it is necessary to advance the tool unchucking unit  51  to the tool exchanging position P 2  and also to move a spindle head  21  (a spindle  23 ) toward the tool unchucking unit  51 , thereby holding the tool chucking mechanism  24  within a tool loosening mechanism  52  of the tool unchucking unit  51 , and loosening the tool chucking mechanism  24  by the tool loosening mechanism  52 . In contrast, at the time of a tool-chucking operation, after a designated tool T is moved from the tool storage device  31  and held within a tool fastening mechanism  42  of the tool chucking unit  41 , it is necessary to advance the tool chucking unit  41  to the tool exchanging position P 2 , and also to move the spindle head  21  (the spindle  23 ) toward the tool chucking unit  41 , thereby holding the tool chucking mechanism  24  within the tool fastening mechanism  42  of the tool chucking unit  41 , and fastening the tool chucking mechanism  24  by the tool fastening mechanism  42 . That is, in this configuration, many movable members are used, and high-precision alignment is required for these individual members. Therefore, such a configuration is complicated, and accordingly has a room for improvement. 
         [0008]    Therefore, a processing apparatus is currently expected which includes a replacement device that can freely and automatically replace a plurality of processing members continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. 
         [0009]    The present invention has been achieved to solve the above problems, and an object of the present invention is to provide a processing apparatus including a replacement device that can freely and automatically replace a plurality of processing members continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. 
         [0010]    To achieve the above object, a first aspect of the present invention is to provide a processing apparatus comprising: a processing tool that includes a drive mechanism, a processing member that is vertically movable to a processing-target member and rotatable to the processing-target member by utilizing a driving force of the drive mechanism, and a holder that detachably holds the processing member through a restricting portion; a moving mechanism that includes an arm to which the processing tool is attached, and that can freely move the processing tool to the processing-target member by moving the arm; and a replacement device that can freely replace the processing member, wherein the replacement device has: a gripping device that includes a single first support member in which a position thereof is fixed, a first gripping portion that is provided on the first support member, and can freely grip the holder not to rotate in a releasing direction when the processing member is removed from the holder, and a second gripping portion that is provided on the first support member apart from the first gripping portion, and can freely grip the holder not to rotate in a restricting direction when the processing member is attached to the holder; and a holding device that includes a single movable second support member, a plurality of first holding portions that are provided on the second support member, and can freely and respectively accommodate the processing member removed from the holder, and a plurality of second holding portions that are provided on the second support member apart from the first holding portions, and can freely and respectively accommodate the processing member to be attached to the holder, and wherein when the processing member is detached from the holder to replace the processing member, the second support member of the holding device is moved, thereby positioning the first support member of the gripping device to extend across both a corresponding one of the first holding portions and a corresponding one of the second holding portions, arranging the corresponding one of the first holding portions vertically below the first gripping portion, and arranging the corresponding one of the second holding portions vertically below the second gripping portion. 
         [0011]    According to a second aspect of the present invention, in addition to the first aspect, the first gripping portion and the second gripping portion of the gripping device, and the processing-target member placed on a placement member are disposed within a movable range of the processing tool, which is defined by movement of the arm by the moving mechanism. 
         [0012]    According to a third aspect of the present invention, in addition to the first or second aspect, the processing apparatus is a friction stir welding apparatus, and the restricting direction is a rotation direction of the friction stir welding apparatus at a time of friction stir welding. 
         [0013]    According to a fourth aspect of the present invention, in addition to any of the first to third aspects, the second support member of the holding device is rotatable about a center axis thereof and is disk-shaped, the first holding portions are disposed on a first circumference to form a first circular line, the second holding portions are disposed on a second circumference to form a second circular line, and when the processing member is detached from the holder to replace the processing member, the second support member is rotated in a state where the first line is positioned vertically below the first gripping portion, and where the second line is positioned vertically below the second gripping portion, thereby feeding each of the first holding portions successively to be positioned vertically below the first gripping portion, and feeding each of the second holding portions successively to be positioned vertically below the second gripping portion. 
         [0014]    According to a fifth aspect of the present invention, in addition to the fourth aspect, a straight line, connecting the first gripping portion and the second gripping portion, is displaced not to pass through a center axis of the second support member. 
         [0015]    According to a sixth aspect of the present invention, in addition to any of the first to fifth aspects, each of the first gripping portion and the second gripping portion grips the holder according to an operation of a ratchet. 
         [0016]    According to a seventh aspect of the present invention, in addition to any of the first to sixth aspects, the gripping device is elastically supported. 
         [0017]    According to an eighth aspect of the present invention, in addition to any of the first to seventh aspects, the processing apparatus further comprises a pressing device that presses at least one of the processing member when the processing member is released from the holder and the processing member when the processing member is attached to the holder. 
         [0018]    According to a ninth aspect of the present invention, in addition to any of the first to eighth aspects, the moving mechanism is an industrial robot. 
         [0019]    According to the first aspect of the present invention, the replacement device of the processing apparatus includes the gripping device that includes the single first support member in which the position thereof is fixed, the first gripping portion that is provided on the first support member, and can freely grip the holder not to rotate in the releasing direction when the processing member is removed from the holder, and the second gripping portion that is provided on the first support member apart from the first gripping portion, and can freely grip the holder not to rotate in the restricting direction when the processing member is attached to the holder, and the holding device that includes the single movable second support member, the first holding portions that are provided on the second support member, and can freely and respectively accommodate the processing member removed from the holder, and the second holding portions that are provided on the second support member apart from the first holding portions, and can freely and respectively accommodate the processing member to be attached to the holder, wherein when the processing member is detached from the holder to replace the processing member, the second support member of the holding device is moved, thereby positioning the first support member of the gripping device to extend across both the corresponding one of the first holding portions and the corresponding one of the second holding portions, arranging the corresponding one of the first holding portions vertically below the first gripping portion, and arranging the corresponding one of the second holding portions vertically below the second gripping portion. Therefore, in a state where the processing member attached to the holder, the first gripping portion, and the corresponding one of the first holding portions are aligned vertically downward in this order, and where the holder having the processing member attached thereto is gripped by the first gripping portion not to rotate, the restricting portion is rotated in the releasing direction, thereby releasing the processing member from the holder, and accommodating the processing member in the corresponding one of the first holding portions. Thereafter, in a state where the holder to which the processing member is not attached, the second gripping portion, and the corresponding one of the second holding portions are aligned vertically downward in this order without moving the support member of the gripping portion, and where the holder to which the processing member is not attached is gripped by the second gripping portion not to rotate, and the processing member held in the corresponding one of the second holding portions is connected to the restricting portion, the restricting portion is rotated in the restricting direction opposite to the releasing direction, thereby attaching the processing member to the holder. Accordingly, the processing members can automatically be replaced continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. 
         [0020]    According to the second aspect of the present invention, the first gripping portion and the second gripping portion of the gripping device, and the processing-target member placed on the placement member are disposed within the movable range of the processing tool, which is defined by movement of the arm by the moving mechanism. Therefore, the overall configuration of the processing apparatus can be kept compact, and also the processing member that requires replacement can automatically be replaced immediately in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. 
         [0021]    According to the third aspect of the present invention, the processing apparatus is the friction stir welding apparatus, and the restricting direction is the rotation direction of the friction stir welding apparatus at the time of friction stir welding. Therefore, even when the processing apparatus is the friction stir welding apparatus to be used at a high rotation speed with a high pressure force, the processing members can automatically be replaced continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced, while realizing high reliability in which the processing member does not come off, for example, at the time of friction stir welding. 
         [0022]    According to the fourth aspect of the present invention, the second support member of the holding device is rotatable about the center axis thereof and is disk-shaped, the first holding portions are disposed on the first circumference to form the first circular line, the second holding portions are disposed on the second circumference to form the second circular line, and when the processing member is detached from the holder to replace the processing member, the second support member is rotated in a state where the first line is positioned vertically below the first gripping portion, and where the second line is positioned vertically below the second gripping portion, thereby feeding each of the first holding portions successively to be positioned vertically below the first gripping portion, and feeding each of the second holding portions successively to be positioned vertically below the second gripping portion. Therefore, while the configuration of the replacement device is made compact, the processing members can automatically be replaced continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. 
         [0023]    According to the fifth aspect of the present invention, the straight line, connecting the first gripping portion and the second gripping portion, is displaced not to pass through the center axis of the second support member. Therefore, the number of the first holding holes to be disposed and the number of the second holding holes to be disposed can be respectively increased, and the number of the processing members to be continuously replaced can be increased. 
         [0024]    According to the sixth aspect of the present invention, each of the first gripping portion and the second gripping portion grips the holder according to an operation of the ratchet. Therefore, the holder can be reliably gripped with a simple configuration, and the processing members can automatically be replaced continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. 
         [0025]    According to the seventh aspect of the present invention, the gripping device is elastically supported. Therefore, while a positional tolerance between the holder and the first and second gripping portions is absorbed, the occurrence of misalignment or the like between them, caused by an unwanted impact on them, can be reduced. 
         [0026]    According to the eighth aspect of the present invention, the processing apparatus further includes the pressing device that presses at least one of the processing member when the processing member is released from the holder and the processing member when the processing member is attached to the holder. Therefore, the pressing member presses the processing member when the processing member is released from the holder, and can encourage detachment of the processing member from the holder. Also the pressing member presses the processing member when the processing member is attached to the holder, and can encourage insertion of the processing member into the restricting portion within the holder. 
         [0027]    According to the ninth aspect of the present invention, the moving mechanism is the industrial robot. Therefore, the processing members can automatically be replaced continuously in a manner of high-precision alignment between constituent components with a more general and simple configuration in which the number of components is reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a side view of an overall configuration of a friction stir welding apparatus according to an embodiment of the present invention; 
           [0029]      FIG. 2  is a top view of a replacement device in the friction stir welding apparatus according to the embodiment; 
           [0030]      FIG. 3  is a schematic top view showing a range where the replacement device in the friction stir welding apparatus according to the embodiment is disposed; 
           [0031]      FIGS. 4A to 4C  are process diagrams showing an operation of the replacement device in the friction stir welding apparatus according to the embodiment; and 
           [0032]      FIGS. 5A to 5C  are process diagrams showing an operation of the replacement device in the friction stir welding apparatus according to the embodiment, and show steps subsequent to those shown in  FIGS. 4A to 4C . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0033]    A processing apparatus according to an embodiment of the present invention is explained in detail below with reference to the accompanying drawings while exemplifying a friction stir welding apparatus. In the drawings, an x-axis, a y-axis, and a z-axis constitute a three-axis orthogonal coordinate system. A plane defined by the x-axis and the y-axis is parallel to a horizontal plane. The direction of the z-axis is a vertical direction, and the positive direction of the z-axis is a vertically upward direction. The processing apparatus of the present invention is also applicable to processing apparatuses including a rotatable processing member that performs mechanical processing such as cutting, drilling, and grinding, in addition to the friction stir welding apparatus explained in the present embodiment. 
         [0034]      FIG. 1  is a side view of an overall configuration of the friction stir welding apparatus according to the present embodiment.  FIG. 2  is a top view of a replacement device in the friction stir welding apparatus according to the present embodiment.  FIG. 3  is a schematic top view showing a range where the replacement device in the friction stir welding apparatus according to the present embodiment is disposed. 
         [0035]    As shown in  FIGS. 1 to 3 , a friction stir welding apparatus  1  includes a replacement device  10  that is fixedly provided on a floor F, a welding tool  30  that can be freely arranged above and opposite to the replacement device  10 , and a robot  50  that is fixedly provided on the floor F and holds the welding tool  30  by an attachment jig  52 . 
         [0036]    Specifically, the replacement device  10  includes a gripping device  12  and a holding device  20 . The gripping device  12  is disposed above the holding device  20 . 
         [0037]    The gripping device  12  includes support legs  14  that are fixedly provided on the floor F, and a support plate  16  that is fixedly provided on the support legs  14 . On the support plate  16 , gripping holes  16   a  and  16   b  are provided, each of which passes through an upper surface and a lower surface of the support plate  16 . A ratchet  16   c  is disposed for the gripping hole  16   a , and a ratchet  16   f  is disposed for the gripping hole  16   b . The support plate  16  is typically made of metal such as steel. However, the support plate  16  is not limited to having a plate shape, and can have other shapes, as long as the support plate  16  has necessary and sufficient strength and rigidity. 
         [0038]    Specifically, the ratchet  16   c  includes a rotary member  16   d  that is rotatable only in a clockwise direction on the x-y plane as viewed in the negative direction of the z-axis (hereinafter, “clockwise direction”), and that includes the gripping hole  16   a  as its inner peripheral hole, and a locking member  16   e  that can freely lock the rotary member  16   d . That is, when the rotary member  16   d  is to rotate in the clockwise direction, the locking member  16   e  does not lock the rotary member  16   d  including the gripping hole  16   a , and allows them to rotate. In contrast, when the rotary member  16   d  is to rotate in a counterclockwise direction on the x-y plane as viewed in the negative direction of the z-axis (hereinafter, “counterclockwise direction”), the locking member  16   e  locks the rotary member  16   d  including the gripping hole  16   a , thereby prohibiting them from rotating. 
         [0039]    The ratchet  16   f  includes a rotary member  16   g  that is rotatable only in the counterclockwise direction, and that includes the gripping hole  16   b  as its inner peripheral hole, and a locking member  16   h  that can freely lock the rotary member  16   g . That is, when the rotary member  16   g  is to rotate in the counterclockwise direction, the locking member  16   h  does not lock the rotary member  16   g  including the gripping hole  16   b , and allows them to rotate. In contrast, when the rotary member  16   g  is to rotate in the clockwise direction, the locking member  16   h  locks the rotary member  16   g  including the gripping hole  16   b , thereby prohibiting them from rotating. 
         [0040]    In the gripping device  12 , it is preferable to dispose an elastic member  18  between the support legs  14  and the support plate  16 . In such a case, the support plate  16  is elastically supported by the support legs  14 . The elastic member  18  can be formed of a rubber member, or can be formed of a spring member and a damper member. 
         [0041]    The holding device  20  includes a shaft member  22  that is fixedly provided on the floor F, and a disk-shaped support plate  24  that is supported on the shaft member  22  to be rotatable about a center axis Z 2  parallel to the z-axis by the driving of a motor or the like (not shown). On the support plate  24 , a plurality of holding holes  24   a  and  24   b  are provided, each of which passes through an upper surface and a lower surface of the support plate  24 . The support plate  24  is typically made of metal, such as steel. However, the support plate  24  is not limited to having a plate shape, and can have other shapes, as long as the support plate  24  has necessary and sufficient strength and rigidity. 
         [0042]    Specifically, the holding holes  24   a  are disposed in a circular line at equal spacing on the outer peripheral side of the support plate  24  on a circumference parallel to the outer periphery of the support plate  24 . This circular line is arranged immediately vertically below the gripping hole  16   a . When the support plate  24  is rotated about the center axis Z 2 , each of the holding holes  24   a  is fed to be successively positioned immediately vertically below the gripping hole  16   a  of the gripping device  12 . 
         [0043]    Furthermore, the holding holes  24   b  are disposed in a circular line at equal spacing on the inner peripheral side of the support plate  24  on a circumference parallel to the outer periphery of the support plate  24 . This circular line is arranged immediately vertically below the gripping hole  16   b . When the support plate  24  is rotated about the center axis Z 2 , each of the holding holes  24   b  is fed to be successively positioned immediately vertically below the gripping hole  16   b  of the gripping device  12 . 
         [0044]    The support plate  16  of the gripping device  12  is positioned to extend across and vertically above the circular line formed by the holding holes  24   a  and the circular line formed by the holding holes  24   b.    
         [0045]    It is preferable to provide a straight line, connecting the center of the gripping hole  16   a  and the center of the griping hole  16   b , to be displaced from the radial direction of the support plate  24  in order not to pass through the center axis Z 2  of the support plate  24 . The reason for this is as follows. In a case where the straight line, connecting the center of the gripping hole  16   a  and the center of the gripping hole  16   b , passes through the center axis Z 2  of the support plate  24 , the gripping hole  16   a  and the gripping hole  16   b  are arranged in the radial direction of the support plate  24 . Therefore, it is necessary to also arrange the holding hole  24   a  and the holding hole  24   b  in the radial direction of the support plate  24 . However, when the straight line, connecting the center of the gripping hole  16   a  and the center of the gripping hole  16   b , is provided to be displaced from the radial direction of the support plate  24  in order not to pass through the center axis Z 2  of the support plate  24 , it is not necessary to arrange the holding hole  24   a  and the holding hole  24   b  in the radial direction of the support plate  24 . Therefore, the line formed by the holding holes  24   a  and the line formed by the holding holes  24   b  are provided close to each other in the radial direction of the support plate  24  by, for example, arranging one holding hole  24   b  between two holding holes  24   a , and both the holding holes  24   a  and the holding holes  24   b  can be provided on an outer peripheral-end side of the support plate  24  in a concentrated manner. As a result, the number of the holding holes  24   a  to be disposed and the number of the holding holes  24   b  to be disposed can be respectively increased, and the number of probes  32  to be continuously replaced can be increased. 
         [0046]    From the viewpoint of the simplicity of making the configuration of the holding device  20  compact, the shape of the support plate  24  is preferably a disk shape. However, the shape of the support plate  24  is not limited to a disk shape, and can be a rectangular plate shape, for example. In a case where the support plate  24  has a rectangular plate shape, the holding holes  24   a  and the holding holes  24   b  are respectively disposed at equal spacing to form lines parallel to each other. In such a case, the support plate  24  is moved in a direction parallel to the horizontal plane by the driving of the motor or the like, and each of the holding holes  24   a  is fed to be successively positioned immediately vertically below the gripping hole  16   a  of the gripping device  12 , and also each of the holding holes  24   b  is fed to be successively positioned immediately vertically below the gripping hole  16   b  of the gripping device  12 . 
         [0047]    In the drawings, each of the holding holes  24   a  and  24   b  is shown in a mode of a through hole. However, each of them can be a recessed bottomed hole with its lower end closed. By providing a flange (not shown) on the probe  32 , and setting the flange to be locked by an upper-end peripheral portion of each of the holding holes  24   a  and  24   b , the probe  32  can be reliably held even when each of the holding holes  24   a  and  24   b  is a through hole. 
         [0048]    Preferably, the replacement device  10  further includes a pressing device  26 . The pressing device  26  is fixed relative to the floor F by, for example, fixedly providing the pressing device  26  between the support legs  14  of the gripping device  12 , and includes pressing members  26   a  and  26   b , each of which is advanceable and retractable. The pressing device  26  does not necessarily include both the pressing members  26   a  and  26   b , and can include either one of them. 
         [0049]    The welding tool  30  that is a processing tool is typically a cylindrical member made of metal, such as iron and extending in the vertical direction. The welding tool  30  includes the probe  32  that is rotatable about a center axis Z 1  parallel to the z-axis and is vertically movable, and that serves as a processing member, a holder  34  that holds the probe  32 , and a drive mechanism  33  that vertically moves the probe  32  held by the holder  34 , and that rotates the probe  32  about the center axis Z 1 . 
         [0050]    The probe  32  is attached to the holder  34  through a restricting portion  32   a  that is coupled with a driving force of the drive mechanism  38 . At the time of a normal operation of the friction stir welding apparatus  1  that performs friction stir welding, the probe  32  is vertically movable and rotatable with the holder  34  and the restricting portion  32   a . In contrast, at the time of replacing the probe  32 , the probe  32  is rotatable relative to the holder  34  through the restricting portion  32   a.    
         [0051]    That is, at the time of the normal operation of the friction stir welding apparatus  1  that performs friction stir welding, the holder  34  and the restricting portion  32   a  do not rotate relative to each other, and a driving force of the drive mechanism  38  is transmitted to the probe  32  through the restricting portion  32   a . The probe  32  rotates in the clockwise direction at the time of friction stir welding. In contrast, at the time of replacing the probe  32 , the holder  34  and the restricting portion  32   a  rotate relative to each other. Therefore, according to the direction of their relative rotations, the probe  32  is fastened to/loosened from the restricting portion  32   a , and is attached to/detached from the holder  34 . The restricting portion  32   a  typically has a chuck structure such as a collet chuck structure. The drive mechanism  38  has a motor, a shaft, and the like (all not shown) incorporated in its casing  38   a.    
         [0052]    The diameter of the gripping hole  16   a  of the gripping device  12  is set to provide a predetermined fastening margin relative to the diameter of the holder  34 . When the holder  34  is inserted into the gripping hole  16   a , the holder  34  is gripped by the gripping hole  16   a  without slipping through. 
         [0053]    Therefore, when the holder  34  with the probe  32  attached is inserted into the gripping hole  16   a , and is to rotate in the clockwise direction, and accordingly the rotary member  16   d  is to rotate in the clockwise direction, the locking member  16   e  does not lock the rotary member  16   d . Consequently, the gripping hole  16   a  that is the inner peripheral hole of the rotary member  16   d  is not locked, and is allowed to rotate, and thus the holder  34  is rotatable in the clockwise direction with the probe  32  and the restricting portion  32   a . In contrast, when the holder  34  with the probe  32  attached is to rotate in the counterclockwise direction, and accordingly the rotary member  16   d  is to rotate in the counterclockwise direction, the locking member  16   e  locks the rotary member  16   d . Consequently, the gripping hole  16   a  that is the inner peripheral hole of the rotary member  16   d  is locked, and is prohibited from rotating, and thus the holder  34  cannot rotate in the counterclockwise direction with the probe  32  and the restricting portion  32   a . As a result, relative rotations are generated between the holder  34 , and the probe  32  and the restricting portion  32   a , and the probe  32  weakens the restricted state between the probe  32  and the restricting portion  32   a , while rotating in the counterclockwise direction with the restricting portion  32   a.    
         [0054]    Furthermore, when the holder  34  with the probe  32  not attached is inserted into the gripping hole  16   b , and is to rotate in the counterclockwise direction, and accordingly the rotary member  16   g  is to rotate in the counterclockwise direction, the locking member  16   h  does not lock the rotary member  16   g . Consequently, the gripping hole  16   b  that is the inner peripheral hole of the rotary member  16   g  is not locked, and is allowed to rotate, and thus the holder  34  is rotatable in the counterclockwise direction. In contrast, when the holder  34  with the probe  32  not attached is to rotate in the clockwise direction, and accordingly the rotary member  16   g  is to rotate in the clockwise direction, the locking member  16   h  locks the rotary member  16   g . Consequently, the gripping hole  16   b  that is the inner peripheral hole of the rotary member  16   g  is locked, and is prohibited from rotating, and thus the holder  34  cannot rotate in the clockwise direction. As a result, relative rotations are generated between the holder  34  and the restricting portion  32   a , and the probe  32 , to be accommodated in and connected to the restricting portion  32   a , strengthens the restricted state between the probe  32  and the restricting portion  32   a.    
         [0055]    At the time of replacing the probe  32 , the support plate  24  of the holding device  20  is rotated about the center axis Z 2 , and therefore the support plate  16  of the gripping device  12  is positioned to extend across and vertically above a corresponding one of the holding holes  24   a  and a corresponding one of the holding holes  24   b . As a result, the corresponding one of the holding holes  24   a  is positioned immediately vertically below the gripping hole  16   a , and also the corresponding one of the gripping holes  24   b  is positioned immediately vertically below the gripping hole  16   b.    
         [0056]    The robot  50  is a moving mechanism that can freely move the welding tool  30 , and is typically an industrial robot. Specifically, the robot  50  includes the attachment jig  52  that attaches the welding tool  30  thereto, an arm  54  that is typically a multijoint manipulator and has the attachment jig  52  attached thereto, and a robot body  56  that has a drive mechanism that moves the arm  54 , a computing processing device, a memory, and the like (all not shown) incorporated therein. The casing  38   a  of the drive mechanism  38  of the welding tool  30  is attached and fixed to the attachment jig  52 . 
         [0057]    As shown in  FIG. 3 , the gripping holes  16   a  and  16   b  of the gripping device  12 , and a processing-target member W placed on a placement table  40  are arranged within a movable range L defined by the movement of the arm  54  of the robot  50  and showing a limited range where the probe  32  and the holder  34  of the welding tool  30  can be positioned. 
         [0058]    Various corresponding constituent elements in the friction stir welding apparatus  1  receive a control signal transmitted from a controller C, and are appropriately controlled, and also operate to perform friction stir welding on the processing-target member W, while automatically replacing the probe  32  as necessary. The controller C has a computing processing device, a memory, and the like (all not shown) incorporated therein. In the memory, a control program for replacing the probe  32  and performing friction stir welding, data regarding a predetermined processing direction, and the like are stored. 
         [0059]    Next, in the friction stir welding apparatus  1  having the above configuration, a replacement operation for automatically replacing the probe  32  is explained below in detail also with reference to  FIGS. 4 and 5 . 
         [0060]      FIGS. 4A to 4C  are process diagrams showing an operation of the replacement device in the friction stir welding apparatus according to the present embodiment.  FIGS. 5A to 5C  are also process diagrams showing an operation of the replacement device in the friction stir welding apparatus according to the present embodiment, and show steps subsequent to those shown in  FIGS. 4A to 4C . 
         [0061]    First, when the probe  32  is worn down or smeared after repeating a friction-stir welding step a predetermined number of times, the arm  54  of the robot  50  is moved to position the probe  32  of the welding tool  30  and the holder  34  with the probe  32  attached vertically above the gripping hole  16   a  of the gripping device  12 , as shown in  FIG. 4A . At this time, the support plate  24  of the holding device  20  is rotated to position an empty holding hole  24   a , in which nothing is held, vertically below the gripping hole  16   a , and also to position the holding hole  24   b , in which a new probe  32  is held, vertically below the gripping hole  16   b.    
         [0062]    Next, as shown in  FIG. 4B , the drive mechanism  38  of the welding tool  30  is driven to vertically lower the probe  32  and the holder  34  with the probe  32  attached. After the probe  32  passes through the gripping hole  16   a , the holder  34  enters into the gripping hole  16   a  to be gripped by the gripping hole  16   a . In this state, when a driving force for generating rotations in the counterclockwise direction is applied to the probe  32  from the drive mechanism  38  through the restricting portion  32   a , the holder  34  is gripped by the gripping hole  16   a , and is prohibited from rotating. Therefore, the restricting portion  32   a  weakens the restricted state of the probe  32  relative to the restricting portion  32   a , while rotating in the counterclockwise direction. When such a restricted state is then weakened completely, a driving force from the drive mechanism  38  is not coupled to the probe  32 . Thereafter, the probe  32  drops off the holder  34  vertically downward by its weight. 
         [0063]    At this time, when the pressing member  26   a  of the pressing device  26  is advanced toward the probe  32  to press the probe  32 , the probe  32  easily comes off the holder  34 . 
         [0064]    Next, as shown in  FIG. 4C , the probe  32  drops vertically downward by its weight, and is caught by an empty holding hole  24   a  of the holding device  20 , and held therein. Simultaneously, the drive mechanism  38  of the welding tool  30  is driven to remove the holder  34  with the probe  32  detached from the gripping hole  16   a , and to raise the holder  34 . At this time, when the restricting portion  32   a  is first rotated in the clockwise direction, and is then rotated in the counterclockwise direction to apply an impact force to the holder  34 , the holder  34  is easily removed from the gripping hole  16   a.    
         [0065]    Next, as shown in  FIG. 5A , the arm  54  of the robot  50  is moved to position the holder  34  with the probe  32  detached vertically above the gripping hole  16   b  of the gripping device  12 . At this time, the holding hole  24   b  in which a new probe  32  is held is positioned vertically below the gripping hole  16   b.    
         [0066]    Next, as shown in  FIG. 5B , the drive mechanism  38  of the welding tool  30  is driven to vertically lower the holder  34  with the probe  32  detached to enter the holder  34  into the gripping hole  16   b  to be gripped by the gripping hole  16   b . Also, the probe  32  held in the holding hole  24   b  is accommodated inside of the holder  34 , and is connected to the restricting portion  32   a  to enter a state where a driving force from the drive mechanism  38  is coupled to the probe  32 . In this state, when a driving force for generating rotations in the clockwise direction is applied to the probe  32  through the restricting portion  32   a , the holder  34  is gripped by the gripping hole  16   b , and is prohibited from rotating. Therefore, the restricting portion  32   a  strengthens the restricted state of the probe  32  relative to the restricting portion  32   a , while rotating in the clockwise direction. After such a restricted state is strengthened completely, a driving force from the drive mechanism  38  is shut off to completely attach the probe  32  to the holder  34  through the restricting portion  32   a.    
         [0067]    At this time, when the pressing member  26   b  of the pressing device  26  is advanced toward the probe  32  to press the probe  32 , the probe  32  is reliably connected to the restricting portion  32   a  easily. 
         [0068]    Next, as shown in  FIG. 5C , the drive mechanism  38  of the welding tool  30  is driven to raise the holder  34  with the probe  32  attached, in order to be prepared for the next friction stir welding. At this time, when the restricting portion  32   a  is first rotated in the counterclockwise direction, and is then rotated in the clockwise direction to apply an impact force to the holder  34 , the holder  34  is easily removed from the gripping hole  16   b.    
         [0069]    Furthermore, when the probe  32  is worn down and smeared after repeating the friction-stir welding step a predetermined number of times, the support plate  24  of the holding device  20  is rotated to position an empty holding hole  24   a , in which nothing is held, vertically below the gripping hole  16   a , and also to position the holding hole  24   b , in which a new probe  32  is held, vertically below the gripping hole  16   b , in order to repeat the above step of replacing the probe  32 . 
         [0070]    In the present invention, the shape, the arrangement, the number, and the like of the members are not limited to those in the embodiment explained above, and it is needless to mention that the constituent elements can be modified as appropriate without departing from the scope of the invention, such as appropriately replacing these elements by other ones having identical operational effects. 
         [0071]    As described above, the present invention can provide a processing apparatus including a replacement device that can freely and automatically replace a plurality of processing members continuously in a manner of high-precision alignment between constituent components with a simple configuration in which the number of components is reduced. Therefore, because of its general purposes and universal characteristics, applications of the present invention are expected in a wide range in the field of machine processing such as friction stir welding of a strength member of a movable body such as an automobile.