Abstract:
The endoscope treatment system includes an endoscope treatment tool that has an operating part having a distal end and a proximal end, and a sheath that is connected to the distal end of the operating part and is formed with a lumen through that enables a guide wire to be inserted therethrough; a guide wire holder around which a tube member housing the guide wire is wound circumferentially; and a fixing member that couples the operating part to the guide wire holder such that the distal end and the proximal end of the operating part are located outside the circumference of the guide wire holder.

Description:
[0001]    This application is a continuation claiming priority on the basis of U.S. Patent Application No. 61/805,256 provisionally applied in US on Mar. 26, 2013 and based on PCT/JP2014/057878 filed on Mar. 20, 2014. The contents of both the PCT application and the U.S. Provisional application are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a treatment tool. 
       BACKGROUND ART 
       [0003]    In the related art, treatment tools having a movable part at a distal end of a bendable elongated insertion part are known as surgical equipment for performing surgical procedures, such as excision of lesions. Additionally, treatment tools which actuate the movable part provided at the distal end of the insertion part with a driving force exerted from a driving source, such as a servo motor, are known. The treatment tools that actuate the movable part with the driving force exerted from the driving source are configured such that the driving force is transmitted to the movable part by a power-transmitting member, such as a wire disposed along the insertion part. The movable part is controlled to make a desired movement on the basis of the amount of displacement of the movable part detected by a detecting part. 
         [0004]    U.S. Pat. No. 8,105,338 discloses a treatment tool in which a treatment-tool-side unit and a drive-unit-side unit having a driving source are detachably coupled together. In the treatment tool described in U.S. Pat. No. 8,105,338, an output part of a driving source and an input part to which the output of the driving source is input to the power-transmitting member are detachably coupled together via a coupling. 
       SUMMARY OF THE INVENTION 
       [0005]    According to a first aspect of the present invention, a treatment tool includes a treatment tool unit having a treatment tool body part and a treatment tool base part; and a drive unit that is detachably combined with the treatment tool base part of the treatment tool unit. The treatment tool body part includes a movable part that is displaced; an insertion part having the movable part; and a driving force transmission member that has a distal end coupled to the movable part, has a proximal end guided to a proximal end side of the insertion part along the insertion part, and transmits a driving force to the movable part to displace the movable part by the driving force being input from the outside to the proximal end; and a displacement amount transmission member that has a distal end coupled to at least one of the driving force transmission member and the movable part, has a proximal end guided to the proximal end side of the insertion part along the insertion part, and transmits the amount of displacement thereof to the proximal end when the movable part has been displaced. The treatment tool base part includes a treatment-tool-unit-side base member that has the proximal end side of the insertion part combined therewith; a driving force input part that is provided in a treatment-tool-unit-side base member, and inputs the driving force from the outside for displacing the movable part to the proximal end of the driving force transmission member; and a displacement amount detected part that is provided at the proximal end of the displacement amount transmission member and is displaced along a given direction by an amount according to the amount of displacement transmitted to the proximal end of the displacement amount transmission member. The drive unit includes a driving source that generates a driving force that actuates the movable part; and a drive-unit-side base member that supports the driving source and has the treatment-tool-unit-side base member of the treatment tool base part detachably coupled thereto. A power transmission joint that detachably couples an output part of the driving source and the driving force input part in a state where power transmission is allowed from the output part of the driving source to the driving force input part when the treatment-tool-unit-side base member is coupled to the drive-unit-side base member, and a displacement amount detecting part that is brought into a state where the amount of displacement of the displacement amount detected part is detectable and that is brought into a state where a detection signal is outputtable from the drive unit side when the treatment-tool-unit-side base member is coupled to the drive-unit-side base member are provided between the treatment tool unit and the drive unit. 
         [0006]    According to a second aspect of the present invention based on the first aspect, the displacement amount detected part may be provided so as to be movable along a direction parallel to a combined surface of the treatment-tool-unit-side base member combined with the drive-unit-side base member, and the displacement amount detecting part may be provided as a displacement amount detecting part for detecting the amount of displacement of the displacement amount detected part in a contactless manner with respect to the displacement amount detected part, at a position on the drive unit side that faces the displacement amount detected part when the treatment-tool-unit-side base member and the drive-unit-side base member are coupled together. 
         [0007]    According to a third aspect of the present invention based on the second aspect, the treatment tool unit may be provided with a positioning portion that positions the displacement amount detecting part with respect to the displacement amount detected part, and the drive unit may be provided with a biasing part for biasing and positioning the displacement amount detecting part provided in the drive unit to the positioning portion provided in the treatment tool unit when the treatment-tool-unit-side base member and the drive-unit-side base member are coupled together. 
         [0008]    According to a fourth aspect of the present invention based on the second aspect, the treatment tool unit may be provided with a positioning portion that positions the displacement amount detecting part with respect to the displacement amount detected part as the displacement amount detecting part provided in the drive unit is fitted to the positioning portion when the treatment-tool-unit-side base member and the drive-unit-side base member are coupled together. 
         [0009]    According to a fifth aspect of the present invention based on the second aspect, the size of the displacement amount detected part may be set to be greater than an expected connection error in a direction along combined surfaces of the treatment-tool-unit-side base member and the drive-unit-side base member when the treatment-tool-unit-side base member and the drive-unit-side base member are coupled together. 
         [0010]    According to a sixth aspect of the present invention based on the first aspect, the displacement amount detecting part may be provided at the position of the treatment tool unit that faces the displacement amount detected part, the treatment tool unit may be provided with a transmitting unit for the detection signal from the displacement amount detecting part, and a receiving unit capable of receiving the detection signal of the displacement amount detecting part from the transmitting unit and outputting the received detection signal to the position of the drive unit where transfer of the detection signal with the transmitting unit is allowed when the treatment-tool-unit-side base member and the drive-unit-side base member are coupled together. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is a configuration view schematically showing the general outline of a treatment tool of a first embodiment of the present invention. 
           [0012]      FIG. 2  is a perspective view showing the relationship between a displacement amount detected part and displacement amount detecting part in the treatment tool of the first embodiment of the present invention. 
           [0013]      FIG. 3  is a configuration view schematically showing the general outline of the treatment tool of the first embodiment of the present invention. 
           [0014]      FIG. 4  is a cross-sectional view as seen from arrow A-A of  FIG. 3 . 
           [0015]      FIG. 5  is a perspective view showing the relationship between the displacement amount detected part and the displacement amount detecting part in the treatment tool of the first embodiment of the present invention. 
           [0016]      FIG. 6  is a cross-sectional view as seen from arrow B-B of  FIG. 5 . 
           [0017]      FIG. 7  is a configuration view of essential parts in a treatment tool of a second embodiment of the present invention. 
           [0018]      FIG. 8  is a configuration view of essential parts in a treatment tool of a third embodiment of the present invention. 
           [0019]      FIG. 9  is a configuration view of essential parts in a treatment tool of a fourth embodiment of the present invention. 
           [0020]      FIG. 10  is a configuration view of essential parts in a treatment tool of a fifth embodiment of the present invention. 
           [0021]      FIG. 11  is a configuration view schematically showing the general outline of a treatment tool of a sixth embodiment of the present invention. 
           [0022]      FIG. 12  is a perspective view showing the relationship between the displacement amount detected part and the displacement amount detecting part in the treatment tool of the sixth embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       [0023]    A treatment tool of a first embodiment of the present invention will be described. 
         [0024]      FIG. 1  is a configuration view schematically showing the general outline of the treatment tool of the first embodiment of the present invention.  FIG. 2  is a perspective view showing the relationship between a displacement amount detected part and a displacement amount detecting part of the treatment tool.  FIG. 3  is a configuration view schematically showing the entire general outline of the treatment tool.  FIG. 4  is a cross-sectional view as seen from arrow A-A of  FIG. 3 . 
         [0025]    As shown in  FIGS. 1 and 3 , a treatment tool M 1  of the present embodiment includes a treatment tool unit  1  and a drive unit  50 . The treatment tool unit  1  includes a treatment tool body part  10  and a treatment tool base part  20 . The treatment tool base part  20  of the treatment tool unit  1  is detachably combined with the drive unit  50 . 
         [0026]    The treatment tool body part  10  has an insertion part  11  having a bendable flexible structure. The insertion part  11  has, for example, a plurality of joints and is freely bent as a whole by being bent in the respective joints. A movable part  12  is provided at the distal end of the insertion part  11 . In the present specification, a description will be made with a side where the movable part  12  is provided being defined as a distal end side, and a treatment tool base part  20  side being defined a proximal end side. 
         [0027]    As shown in  FIG. 3 , the movable part  12  in the present embodiment is displaced (is operated to rotate in a direction of arrow X 10 ) with respect to a central axis of the insertion part  11  by the movement (directions of arrows X 1  and X 2 ) of a driving wire  31  to be described below. As the movable part  12  is displaced in this way, the insertion part  11  is operated for bending. The movable part  12  is provided with forceps having a gripping part  12 A and a link  13 . The gripping part  12 A of the forceps performs the opening/closing operation (directions of arrows X 5  and X 6 ) in accordance with the movement in central axis directions (directions of arrows X 3  and X 4  direction) of the insertion part  11  using a wire  13 A connected to a proximal end of the link  13 . The wire  13 A is operated by well-known mechanisms, such as a motor (not shown). 
         [0028]    The driving wire  31  and a sensing wire  32  are inserted into the insertion part  11 . The driving wire  31  and the sensing wire  32  are movable back and forth along a longitudinal axis of the insertion part  11  by being guided by wire guides  33  and  34 , respectively. 
         [0029]    The driving wire  31  is a driving force transmission member for bending a distal end portion of the insertion part  11 . In the present embodiment, two driving wires  31  are inserted into the insertion part  11 . A distal end  31   a  of each driving wire is fixed to the movable part  12  at the distal end of the insertion part  11 . A proximal end  31   b  of each driving wire  31  is fixed to an outer peripheral surface of a pulley  35  provided in the treatment tool base part  20 . The driving wire  31  may have a U shape in which both ends are fixed to the movable part  12  at the distal end of the insertion part  11  and an intermediate portion is disposed in the treatment tool base part  20  via the pulley  35 . 
         [0030]    The distal end  31   a  of each driving wire  31  is fixed to a position where this distal end faces the movable part  12  at the distal end of the insertion part  11  in a radial direction of the insertion part  11 , and if one of the two driving wires  31  is pulled to the proximal end side, the distal end of the insertion part  11  is bent toward the pulled driving wire  31  side. 
         [0031]    The sensing wire  32  is a displacement amount transmission member provided to detect the displacement amount of a distal end portion (a portion having the joints) of the movable part  12 , that is, the bending amount of the insertion part  11 . A distal end  32   a  of the sensing wire  32  is fixed to the movable part  12  at the distal end of the insertion part  11 , and a proximal end of the sensing wire  32  is connected to a displacement amount detected part  40  in the treatment tool base part  20 . 
         [0032]    The sensing wire  32  has a configuration in which the sensing wire does not receive an unnecessary external force as the elongation of the sensing wire  32  does not influence a proximal end  32   b  side of the sensing wire  32  to the utmost. For example, the sensing wire  32  may be fixed only to two places of the movable part  12  at the distal end of the insertion part  11  and the displacement amount detected part  40 , and portions other than both ends of the sensing wire  32  may have a coating for reducing sliding resistance. 
         [0033]    The wire guide  33  is a tubular member having flexibility that defines a path for the driving wire  31  and guides the driving wire  31 . The wire guide  33  of the driving wire  31  is formed from, for example, a coil pipe. The wire guide  34  is a tubular member having flexibility that defines a path for the sensing wire  32  and guides the sensing wire  32 . 
         [0034]    The wire guide  34  of the sensing wire  32  is formed from, for example, a coil pipe or a metallic pipe. Additionally, an inner surface of the wire guide  34  and an outer surface of the sensing wire  32  may be subjected to surface treatment or the like such that the friction therebetween becomes small. 
         [0035]    The treatment tool base part  20  includes a treatment-tool-unit-side base member  21  with which the proximal end side of the insertion part  11  of the treatment tool body part  10  is combined. The proximal end  31   b  of the driving wire  31  is delivered onto the treatment tool base part  20  from the wire guide  33 . The treatment-tool-unit-side base member  21  is provided with the pulley (driving force input part)  35  with which the respective proximal ends  31   b  of the respective driving wires  31  are wound. The pulley  35  is a driving force input part that receives a force (for example, a rotational driving force from the outside) used as a pulling force for the movable part  12  at the distal end of the insertion part  11  and inputs the force to the proximal end  31   b  of the driving wire  31 . 
         [0036]    As shown in  FIG. 4 , the pulley  35  is rotatably supported by the treatment-tool-unit-side base member  21  via a bearing  37 . As the pulley  35  rotates, as shown in  FIG. 3 , the driving wire  31  is pushed in the direction of arrow X 1 , or is pulled in the direction of arrow X 2 . 
         [0037]    Additionally, as shown in  FIG. 3 , the proximal end  32   b  of the sensing wire  32  is delivered on the treatment tool base part  20  from the wire guide  34 . The displacement amount detected part  40  is coupled to the proximal end  32   b  of the sensing wire  32 . The displacement amount detected part  40  is a member that is displaced by the amount of displacement transmitted to the proximal end  32   b  of the sensing wire  32 . The displacement amount detected part  40  is slidably supported by the treatment-tool-unit-side base member  21  so as to be displaced in a given direction by a sliding guide mechanism  45 . 
         [0038]    The drive unit  50  has a drive-unit-side base member  51 . The drive-unit-side base member  51  is provided with a drive motor (driving source)  55  that generates a driving force for actuating the movable part  12  of the treatment tool unit  1 . 
         [0039]    The drive-unit-side base member  51  is provided with a combined surface  51   a  where the drive-unit-side base member  51  and the treatment-tool-unit-side base member  21  are combined together when the treatment tool unit  1  is coupled to the drive unit  50 . Similarly, the treatment-tool-unit-side base member  21  is provided with a combined surface  21   a  where the drive-unit-side base member  51  and the treatment-tool-unit-side base member  21  are combined together when the treatment tool unit  1  is coupled to the drive unit  50 . 
         [0040]    The drive unit  50  and the treatment tool unit  1  are combined together with bolts or clamp mechanisms (not shown) in a state where the combined surfaces  51   a  and  21   a  of the drive-unit-side base member  51  and the treatment-tool-unit-side base member  21  are combined together. 
         [0041]    The drive unit  50  is provided with a displacement amount detecting part  60  that is brought into a state where the amount of displacement of the displacement amount detected part  40  can be detected in a contactless manner when the treatment-tool-unit-side base member  21  is coupled to the drive-unit-side base member  51 . The displacement amount detecting part  60  outputs a signal, which is obtained by detecting the amount of displacement of the displacement amount detected part  40 , from the drive unit  50  side. For example, the displacement amount detecting part  60  has an optical encoder. 
         [0042]    As shown in  FIG. 2 , the displacement amount detecting part  60  is provided at a position where the displacement amount detecting part faces a detected surface  40   a  of the displacement amount detected part  40  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. The displacement amount detected part  40  is provided so as to be slidable in a direction parallel to the combined surface  21   a  of the treatment-tool-unit-side base member  21 . The detected surface  40   a  of the displacement amount detected part  40  is formed as a flat surface parallel to the combined surface  21   a  of the treatment-tool-unit-side base member  21 . 
         [0043]    The detected surface  40   a  of the displacement amount detected part  40  is provided with a high-reflection portion  40   b  from which detection light  61  is strongly reflected and a low-reflection portion  40   c  from which the detection light is weakly reflected when the displacement amount detecting part  60  irradiates the detected surface  40   a  with the detection light  61 . The high-reflection portion  40   b  and the low-reflection portion  40   c  are alternately arrayed at regular pitches in a sliding direction of the displacement amount detected part  40 . Therefore, the displacement amount detecting part  60  can detect the amount of displacement of the displacement amount detected part  40  by counting the intensity of the reflected light when the displacement amount detected part  40  slides. 
         [0044]    As shown in  FIG. 4 , a coupling (power transmission joint)  70 , which detachably couples an output shaft (output part)  55   a  of the drive motor  55  with a rotating shaft  35   a  of the pulley  35 , is provided between the drive unit  50  and the treatment tool base part  20 . The coupling  70  is, for example, a concavo-convex fitting type coupling that can transmit rotary power. The coupling  70  is constituted of a first coupling portion  56  that is provided on the output shaft  55   a  side of the drive motor  55 , and a second coupling portion  36  that is provided on the rotating shaft  35   a  side of the pulley  35 . When the treatment-tool-unit-side base member  21  is coupled to the drive-unit-side base member  51 , the first coupling portion  56  and the second coupling portion  36  are fitted to each other, and are brought into a state where rotational power can be transmitted from the output shaft  55   a  of the drive motor  55  to the pulley  35 . 
         [0045]      FIG. 5  is a perspective view showing the relationship between the displacement amount detected part  40  and the displacement amount detecting part  60  in the treatment tool M 1  of the embodiment.  FIG. 6  is a cross-sectional view as seen from arrow B-B of  FIG. 5 . As shown in  FIGS. 5 and 6 , the treatment-tool-unit-side base member  21  is provided with a bracket  46 . A sliding member  41  is attached to the bracket  46  via a sliding guide mechanism  45 . The displacement amount detected part  40  is provided parallel to the sliding direction of the sliding member  41  and parallel to the combined surface  21   a  of the treatment-tool-unit-side base member  21 , in the sliding member  41 . 
         [0046]    The sliding guide mechanism  45  is constituted of a linear guide mechanism  44  having a guide rail  42  that is fixed to the bracket  46  and a slider  43  that is linearly guided along the guide rail  42 . The sliding member  41  provided with the displacement amount detected part  40  is attached to the slider  43  of the linear guide mechanism  44 . Accordingly, the sliding member  41  is slidably supported by the treatment-tool-unit-side base member  21  via the sliding guide mechanism  45  in directions (directions of arrows X 7  and X 8 ) in which the guide rail  42  of the linear motion guide mechanism  44  extends. 
         [0047]    Additionally, a pulling spring  49  is provided between a pin  47  fixed to the bracket  46  and a pin  48  fixed to the sliding member  41 . Accordingly, the sliding member  41  is always biased such that the sensing wire  32  is pulled to the proximal end side (direction of arrow X 8 ). The proximal end  32   b  of the sensing wire  32  is coupled to an end portion of the sliding member  41  on the distal end side (arrow X 7  side). The sensing wire  32  is held in a state where loosening is removed due to the pulling force of the pulling spring  49 . The magnitude of the pulling force of the pulling spring  49  is set to such a degree that the sliding member  41  can move to the distal end side along the guide rail  42  with the pulling force transmitted via the driving wire  31 , the movable part  12 , the sensing wire  32 , and the sliding member  41  from the drive motor  55 . 
         [0048]    The displacement amount detecting part  60  is attached to the drive-unit-side base member  51  via a bracket  52 . A detecting part (part that emits the detection light  61  and receives reflected light) of the displacement amount detecting part  60  can irradiate the detected surface  40   a  (refer to  FIG. 2 ) of the displacement amount detected part  40  with the detection light  61  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. 
         [0049]    The operation of the treatment tool M 1  of the present embodiment will be described. 
         [0050]    When the treatment tool M 1  is used, a user combines the treatment tool base part  20  of the treatment tool unit  1  with the drive unit  50 . This combination is performed in a state where the combined surface  21   a  of the treatment-tool-unit-side base member  21  and the combined surface  51   a  of the drive-unit-side base member  51  are combined together. If the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together, the first coupling portion  56  and the second coupling portion  36  of the coupling  70  are coupled together. Accordingly, a state where the rotational driving force of the drive motor  55  can be transmitted to the pulley  35  is brought about. 
         [0051]    Additionally, if the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together, the detecting part of the displacement amount detecting part  60  on the drive unit  50  side faces the displacement amount detected part  40  of the treatment tool base part  20 . Therefore, the displacement amount detecting part  60  is brought into a state where the amount of displacement of the displacement amount detected part  40  in the sliding direction can be detected. 
         [0052]    In this state, if the drive motor  55  rotates, the rotation of the drive motor  55  is transmitted to the pulley  35 . If the pulley  35  rotates, the driving wire  31  is operated to move back and forth in the direction of arrow X 1  and X 2  of  FIG. 3 . If the driving wire  31  is operated to move back and forth, the distal end portion of the insertion part  11  is operated for bending in the direction of arrow X 10 . 
         [0053]    On the other hand, if the distal end portion of the insertion part  11  is operated for bending in the direction of arrow X 10 , the sliding member  41  and the displacement amount detected part  40  are displaced in the directions of arrows X 7  and X 8  together with the proximal end  32   b  of the sensing wire  32 . When the displacement amount detected part  40  is displaced, the amount of displacement is detected by the displacement amount detecting part  60 . A detection signal of the amount of displacement detected by the displacement amount detecting part  60  is output to the outside if necessary. 
         [0054]    In the present embodiment, although the distal end of the wire guide  34  of the sensing wire  32 , as shown in  FIG. 3 , is located at a position up to the vicinity of a joint on the proximal end side among the plurality of joints and is adapted to detect the bending amount of a portion in front of this position, the distal end of the wire guide  34  may be extended to the distal end side and be adapted to detect the amount of displacement in front of this distal end side. For example, the distal end of the wire guide  34  is located at a position up to the vicinity of the movable part  12 , and detects the amount of rotation of the movable part  12  in front thereof. 
         [0055]    In the treatment tool M 1  of the present embodiment, the displacement amount detected part  40  is provided on the treatment tool unit  1  side. Meanwhile, the displacement amount detecting part  60  is provided on the drive unit  50  side. Therefore, when the treatment tool unit  1  and the drive unit  50  are coupled together, deviation may occur in the correspondence relationship between the displacement amount detected part  40  and the displacement amount detecting part  60 . 
         [0056]    However, in the treatment tool M 1  of the present embodiment, the sliding direction of the displacement amount detected part  40  is set to the direction parallel to the combined surface  21   a  of the treatment-tool-unit-side base member  21 . Additionally, the displacement amount detecting part  60  can detect the amount of displacement of the displacement amount detected part  40  in a contactless manner. Therefore, even if there is an error, deviation, or the like in a direction along the combined surface  21   a , the displacement amount detecting part  60  can precisely detect the amount of displacement of the displacement amount detected part  40  simply by origin adjustment being performed. 
         [0057]    Therefore, according to the present treatment tool M 1 , attachment and detachment of the treatment tool unit  1  with respect to the drive unit  50  can be performed without degrading the detection precision of the amount of displacement of the movable part  12 . 
         [0058]    In the above embodiment, an example of the displacement amount detected part  40  in which the high-reflection portion  40   b  and the low-reflection portion  40   c  are alternately arrayed at regular pitches is shown as an example of the displacement amount detected part  40 . However, other displacement amount detected parts can also be adopted. For example, a displacement amount detected part in which slits are formed instead of the high-reflection portion  40   b  and the low-reflection portion  40   c  can also be adopted. 
         [0059]    Additionally, in the above embodiment, the optical encoder is mentioned as an example of the non-contact type displacement amount detecting part  60 . However, a sensor that magnetically detects the amount of displacement can be used as another detecting part. When the magnetic sensor that magnetically detects the amount of displacement is used, a sensor in which magnets are arrayed is used instead of the array of the high-reflection portion  40   b  and the low-reflection portion  40   c  of the displacement amount detected part. 
         [0060]    Additionally, in the above embodiment, the combination in which the amount of displacement is detected in a digital manner is used as the combination of the displacement amount detected part  40  and the displacement amount detecting part  60 . However, the combination of the displacement amount detected part  40  and the displacement amount detecting part  60  that detects the amount of displacement in an analog manner may be used. 
       Second Embodiment 
       [0061]    Next, a treatment tool M 2  of a second embodiment of the present invention will be described. In respective embodiments to be described below, the same constituent elements as those of the above-described first embodiment will be designated by the same reference numerals, and duplicate description will be omitted. 
         [0062]      FIG. 7  is a configuration view of essential parts in the treatment tool of the second embodiment of the present invention. 
         [0063]    As shown in  FIG. 7 , in the present treatment tool M 2 , the displacement amount detecting part  60  is provided so as to be movable with respect to the combined surface  51   a  of the drive-unit-side base member  51  with a spring  68  of which one end is fixed to the drive-unit-side base member  51 . That is, the one end of the spring  68  is fixed to the drive-unit-side base member  51 , and the other end of the spring  68  is fixed to the displacement amount detecting part  60 . Additionally, the displacement amount detecting part  60  is pressed against an end surface of the bracket  46  by the spring  68 . The end surface of the bracket  46  defines the distance between the displacement amount detecting part  60  and the detected surface  40   a . The other configuration is the same as that of the first embodiment. 
         [0064]    The same effects as those of the above-described first embodiment can also be exhibited even in the present embodiment. 
         [0065]    Moreover, in the treatment tool M 2  of the present embodiment, the displacement amount detecting part  60  on the drive unit  50  side is pressed against the combined surface  21   a  of the treatment-tool-unit-side base member  21  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. Therefore, the present treatment tool M 2  can prevent any deviation from occurring in the positional relationship between the displacement amount detecting part  60  and the displacement amount detected part  40  in the direction orthogonal to the combined surface  21   a . Therefore, the detection precision of the amount of displacement of the movable part  12  does not easily degrade. 
         [0066]    In the above embodiment, the displacement amount detecting part  60  is pressed against the combined surface  21   a  of the treatment-tool-unit-side base member  21  with a biasing force of the spring  68 . However, the displacement amount detecting part  60  may be pressed against the combined surface  21   a  of the treatment-tool-unit-side base member  21  with a magnetic force of a magnet. 
       Third Embodiment 
       [0067]    Next, a treatment tool M 3  of a third embodiment of the present invention will be described. 
         [0068]      FIG. 8  is a configuration view of essential parts in the treatment tool of the third embodiment of the present invention. As shown in  FIG. 8 , in the present treatment tool M 3 , similar to the second embodiment, the displacement amount detecting part  60  is provided so as to be movable in the direction orthogonal to the combined surface  51   a  of the drive-unit-side base member  51 . One end of the spring  68  is fixed to the drive-unit-side base member  51 . The displacement amount detecting part  60  is fixed to the other end of the spring  68 , and is movable with respect to the drive-unit-side base member  51 . Moreover, the displacement amount detecting part  60  is housed in a sliding hole  58  of the drive-unit-side base member  51 . 
         [0069]    The displacement amount detecting part  60  is biased toward the displacement amount detected part  40  of the treatment tool base part  20  by the spring  68  provided in the drive unit  50 . Additionally, a positioning hole  63  of which an inlet is formed as a taper  62  is provided in the treatment tool base part  20  as a positioning portion of the displacement amount detecting part  60 . An abutment wall  64  is provided at a deep end of the positioning hole  63 . The abutment wall  64  is provided with a through-hole  65 . 
         [0070]    The same effects as those of the above-described first embodiment can also be exhibited even in the present embodiment. 
         [0071]    Moreover, in the treatment tool M 3  of the present embodiment, the displacement amount detecting part  60  on the drive unit  50  side is inserted into the positioning hole  63  of the treatment tool base part  20  while being guided by the taper  62  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. The inserted displacement amount detecting part  60  is positioned in a plane parallel to the combined surface  21   a  of the treatment-tool-unit-side base member  21  with respect to the displacement amount detected part  40  by the position thereof being regulated by a peripheral wall of the positioning hole  63 . Additionally, as the distal end of the displacement amount detecting part  60  bumps against an abutment wall  64 , the displacement amount detecting part is positioned in the direction orthogonal to the combined surface  21   a  of the treatment-tool-unit-side base member  21 , with respect to the displacement amount detected part  40 . 
         [0072]    Therefore, the present treatment tool M 3  can prevent any positional deviation from occurring between the displacement amount detecting part  60  and the displacement amount detected part  40  in the direction parallel to the combined surface  21   a  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. Additionally, the present treatment tool M 3  can prevent any positional deviation from occurring between the displacement amount detecting part  60  and the displacement amount detected part  40  in the direction orthogonal to the combined surface  21   a . Therefore, degradation of the detection precision of the amount of displacement of the movable part  12  is prevented. 
       Fourth Embodiment 
       [0073]    Next, a treatment tool M 4  of a fourth embodiment of the present invention will be described.  FIG. 9  is a configuration view of essential parts in the treatment tool of the fourth embodiment of the present invention. As shown in  FIG. 9 , in the present treatment tool M 4 , similar to the second and third embodiments, the displacement amount detecting part  60  is provided so as to be movable in the direction orthogonal to the combined surface  51   a  of the drive-unit-side base member  51 . 
         [0074]    The displacement amount detecting part  60  is biased toward the displacement amount detected part  40  of the treatment tool base part  20  by the spring  68  provided in the drive unit  50 . Additionally, a tapered polygonal positioning hole  63  of which an inlet is widened is provided in the treatment tool base part  20  as a positioning portion of the displacement amount detecting part  60 . Additionally, the shape of an outer peripheral surface of the displacement amount detecting part  60  is formed in a tapered shape that is fitted to the positioning hole  63  with no gap. 
         [0075]    The same effects as those of the above-described first embodiment can also be exhibited even in the present embodiment. 
         [0076]    Moreover, in the treatment tool M 4  of the present embodiment, the displacement amount detecting part  60  on the drive unit  50  side is fitted to the positioning hole  63  of the treatment tool base part  20  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. The fitted displacement amount detecting part  60  is positioned in the plane parallel to the combined surface  21   a  of the treatment-tool-unit-side base member  21  with respect to the displacement amount detected part  40  by the position thereof being regulated by the peripheral wall of the positioning hole  63 . Additionally, the displacement amount detecting part  60  is positioned in the direction orthogonal to the combined surface  21   a  of the treatment-tool-unit-side base member  21 , with respect to the displacement amount detected part  40 . 
         [0077]    Therefore, the present treatment tool M 4  can prevent any positional deviation from occurring between the displacement amount detecting part  60  and the displacement amount detected part  40  in the direction parallel to the combined surface  21   a  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together. Additionally, the present treatment tool M 4  can prevent any positional deviation from occurring between the displacement amount detecting part  60  and the displacement amount detected part  40  in the direction orthogonal to the combined surface  21   a . Therefore, degradation of the detection precision of the amount of displacement of the movable part  12  is prevented. 
       Fifth Embodiment 
       [0078]    Next, a treatment tool M 5  of a fifth embodiment of the present invention will be described.  FIG. 10  is a configuration view of essential parts in the treatment tool of the fifth embodiment of the present invention. As shown in  FIG. 10 , the present treatment tool M 5  has a feature in terms of the size of the rectangular detected surface  40   a  of the displacement amount detected part  40 . For example, when the size of the detected surface  40   a  in the sliding direction (directions of arrows X 7  and X 8 ) of the displacement amount detected part  40  is defined as a dimension  40 X and the size of the detected surface  40   a  in a direction (direction of arrow Y) orthogonal to the sliding direction of the displacement amount detected part  40  is defined as a dimension  40 Y, the dimensions  40 X and  40 Y are sets to be greater than an expected connection error in a direction along the combined surfaces  21   a  and  51   a  when combining the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  together. 
         [0079]    In the present treatment tool M 5 , even in a case where any deviation occurs in the direction along the combined surfaces  21   a  and  51   a  when the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51  are coupled together, the displacement amount detected part  40  and the displacement amount detecting part  60  appropriately correspond to each other. That is, even if any deviation occurs in the direction along the combined surfaces  21   a  and  51   a , the displacement amount detected part  40  is configured such that the detection light  61  from the displacement amount detecting part  60  reaches a suitable position. Therefore, even in the present embodiment, the position detection of the movable part  12  is allowed without being influenced by the positional deviation between the treatment-tool-unit-side base member  21  and the drive-unit-side base member  51 . 
       Sixth Embodiment 
       [0080]    Next, a treatment tool M 6  of a sixth embodiment of the present invention will be described. 
         [0081]      FIG. 11  is a configuration view schematically showing the general outline of the treatment tool of the sixth embodiment of the present invention.  FIG. 12  is a perspective view showing the relationship between the displacement amount detected part and the displacement amount detecting part of the treatment tool. 
         [0082]    In the above first to fourth embodiments, the displacement amount detecting part  60  is provided on the drive unit  50  side. In contrast, as shown in  FIGS. 11 and 12 , in a treatment tool unit  101  of the treatment tool M 6  of the present embodiment, the displacement amount detecting part  60  is provided not in a drive unit  150  side but in a treatment tool base part  120 . Additionally, the treatment tool base part  120  is provided with a transmitting unit  160  that transmits a signal to the displacement amount detecting part  60 . Meanwhile, the drive unit  150  is provided with a receiving unit  170  that can receive a detection signal output from the transmitting unit  160  and can take out the detection signal to the outside. 
         [0083]    The transmitting unit  160  and the receiving unit  170  are brought into a receivable state when the treatment-tool-unit-side base member  21  is coupled to the drive-unit-side base member  51 . A cable type having contact points that are electrically connected to each other when the treatment-tool-unit-side base member  21  is coupled to the drive-unit-side base member  51  can be adopted as the transmitting unit  160  and the receiving unit  170 . In addition to this, a wireless type can also be adopted as the transmitting unit  160  and the receiving unit  170 . 
         [0084]    In the treatment tool M 6  of the present embodiment, since both the displacement amount detecting part  60  and the displacement amount detected part  40  are provided in the treatment tool base part  120 , a fixed correspondence relationship is obtained regardless of the combination of the treatment tool unit  101  and the drive unit  150 . Therefore, the displacement amount detecting part  60  can precisely detect the amount of displacement of the movable part  12 , without being influenced by an error or deviation caused by the combination of the treatment tool unit  101  and the drive unit  150 . 
         [0085]    Although a case where the bending as the displacement of the movable part  12  is taken as an example has been described in the above embodiments, the present invention is not limited to this, and for example, the amount of opening and closing of the gripping part  12 A provided in the movable part  12  may be detected as the displacement. In this case, it is preferable to couple the distal end  32   a  of the sensing wire  32  to the vicinity of the wire  13 A of the link  13 . Moreover, the displacements of both the bending and the opening and closing may be detected by coupling the distal end  32   a  of the sensing wire  32  to the movable part  12  (the distal end of the insertion part  11 ) and the wire  13 A, respectively. 
         [0086]    Additionally, a mechanism for the movable part  12  may be, for example, a linear motion without being limited to the bending and the opening and closing. Moreover, the position of the movable part  12  is not limited to the distal end of the insertion part  11 , and for example, a linear motion mechanism may also be located in the middle of the insertion part  11 . 
         [0087]    While the preferred embodiments of the present invention have been described and shown above, it should be understood that these are exemplary of the present invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications of components can be made without departing from the concept of the present invention. 
         [0088]    Additionally, the present invention is not to be considered as being limited by the foregoing description, and is limited only by the scope of the appended claims.