Patent Publication Number: US-10772486-B2

Title: Endoscope

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2015-209125, filed on Oct. 23, 2015. The above application is hereby expressly incorporated by reference, in its entirety, into the present application. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an endoscope, and more particularly to an endoscope including an insertion section whose leading end is provided with a treatment tool elevator (hereinafter referred to simply as an elevator) that controls a leading direction of a treatment tool. 
     Description of the Related Art 
     In conventional endoscopes, there are known an ultrasound endoscope and a side-viewing endoscope each of which includes a treatment tool leading section through which various treatment tools inserted from a treatment tool inlet provided in an operation section lead out from their leading ends, and an elevator provided in the treatment tool leading section to control a leading direction of a treatment tool. 
     Japanese Patent Application Laid-Open No. 2013-183964 (Patent Literature 1) provides a treatment tool leading section that includes an elevator whose leading end is widened to reduce a gap portion where an operation wire for driving an elevator is disposed to prevent a treatment tool from dropping into a side of the elevator, or the gap portion. 
     Conventionally, a cleaning brush is used to clean the treatment tool leading section provided with the elevator, and thus if a gap portion on a side of the elevator (particularly a leading end thereof) in the treatment tool leading section is reduced as described in Patent Literature 1 to prevent the treatment tool from dropping into the gap portion, bristles of the cleaning brush also tend to be difficult to enter the gap portion. In Patent Literature 1, even if a raising angle of the elevator is changed, a size of the gap portion on a side of the elevator as well as easiness of cleaning does not change because the whole of the elevator is buried in a recessed portion. Thus, there is a problem of requiring time and effort for cleaning operation. 
     The present invention is made in light of the above-mentioned circumstances, and has an object to provide an endoscope capable of reducing time and effort required for cleaning operation of an elevator. 
     SUMMARY OF THE INVENTION 
     To achieve the object described above, an endoscope in accordance with an aspect of the present invention includes: an insertion section having a leading end and a base end; an operation section provided at the base end of the insertion section; a leading end body provided at the leading end of the insertion section; an elevator accommodation groove provided in the leading end body, the groove having an opening in a side face of the leading end body; a treatment tool insertion channel provided in the insertion section, the channel communicating with the elevator accommodation groove; and a treatment tool elevator provided in the elevator accommodation groove to be rotatable around a rotation axis in a direction including a component of a direction orthogonal to a longitudinal axis of the insertion section, the base guiding a treatment tool led through the treatment tool insertion channel. In the endoscope, the treatment tool elevator has a proximal end portion, a distal end portion with a radial distance from the rotation axis more than a radial distance to the proximal end portion from the rotation axis, a treatment tool guiding face provided between the proximal end portion and the distal end portion, and an elevator side face adjacent to the treatment tool guiding face, the side face having a direction including an axial component of the rotation axis, the direction being a normal direction. The elevator accommodation groove has an elevator accommodation groove side face facing the elevator side face across a gap portion. In a state where the treatment tool elevator is lying, the gap portion has: a narrow gap portion formed between a distal end portion side face positioned on a distal end portion side in the elevator side face, and the elevator accommodation groove side face; and a wide gap portion formed between a proximal end portion side face closer to the proximal end portion than the distal end portion side face in the elevator side face, and the elevator accommodation groove side face, the wide gap portion being wider axially than the narrow gap portion. In a state where the treatment tool elevator rises, the distal end portion side face projects outside from the opening of the elevator accommodation groove. 
     According to the present aspect, in a state where the elevator is lying, the narrow gap portion is provided between the distal end portion side face of the elevator, and elevator accommodation groove side face to prevent a treatment tool from dropping into the gap portion from the elevator. When the elevator rises, the distal end portion side face of the elevator projects outside from the opening of the elevator accommodation groove to allow also the distal end portion side face of the elevator, adjacent to the narrow gap portion, to be easily cleaned by using a cleaning brush. 
     In another aspect of the present invention, the treatment tool elevator may include a wide body portion that projects outside from the opening of the elevator accommodation groove when the treatment tool elevator provided on the distal end portion side rises, and a narrow body portion that is provided closer to the proximal end portion than the wide body portion, and is narrower axially than the wide body portion. 
     In yet another aspect of the present invention, the wide body portion may have a longitudinal section with a rounded shape with respect to an axial direction of the wide body portion. 
     In yet another aspect of the present invention, the wide body portion may have a cross section with a rounded shape with respect to the axial direction of the wide body portion. 
     In yet another aspect of the present invention, in a state where the treatment tool elevator is lying, the elevator accommodation groove may include a narrow groove that is provided on the distal end portion side, and a wide groove that is provided closer to the proximal end portion than the narrow groove and is wider axially than the narrow groove. 
     In yet another aspect of the present invention, the elevator accommodation groove may include a leading portion that increases in axial width toward the opening. 
     In yet another aspect of the present invention, the leading portion may be an edge of the elevator accommodation groove on an opening side, the edge having a cross section with a rounded shape. 
     In yet another aspect of the present invention, a back face of the treatment tool elevator, the back face being opposite to the treatment tool guiding face, may have a longitudinal section with a rounded shape with respect to the axial direction. 
     In yet another aspect of the present invention, the endoscope may include a raising lever that is provided in the leading end body and is coupled to the treatment tool elevator to turn the treatment tool elevator around the rotation axis, and a transfer member that is provided from the operation section to the leading end body through the insertion section and transfers displacement generated in the operation section to the raising lever. 
     According to the present invention, time and effort required for cleaning operation of the elevator can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a general structural view of an ultrasound inspection system including an ultrasound endoscope to which the present invention is applied; 
         FIG. 2  is a perspective view illustrating a leading end section of the ultrasound endoscope to which the present invention is applied; 
         FIG. 3  is a plan view illustrating the leading end section of the ultrasound endoscope to which the present invention is applied; 
         FIG. 4  is a perspective view illustrating the whole of an elevator assembly viewed from the left side; 
         FIG. 5  is a perspective view illustrating the whole of the elevator assembly viewed from the right side; 
         FIG. 6  is an exploded perspective view of the elevator assembly; 
         FIG. 7  is a sectional view viewed from a direction of arrows  7 - 7  in  FIG. 3 ; 
         FIG. 8  is a front view of an elevator and a raising lever in a coupling mechanism that couples the elevator and the raising lever to each other; 
         FIG. 9  is a sectional view of the coupling mechanism in the elevator assembly, taken along a plane including an axis of an elevator rotation shaft portion, the plane being perpendicular to an axis of an insertion section; 
         FIG. 10  is an enlarged perspective view illustrating an elevator body; 
         FIG. 11  is an enlarged front view illustrating the elevator body; 
         FIG. 12  is a sectional view of the elevator rotation shaft portion in the leading end section with respect to a direction orthogonal to a direction of the axis of the elevator rotation shaft portion in a state where the elevator is lying; 
         FIG. 13  is a sectional view of the elevator rotation shaft portion in the leading end section with respect to the direction orthogonal to the direction of the axis of the elevator rotation shaft portion in a state where the elevator rises; 
         FIG. 14  is a top view illustrating a peripheral portion of the elevator in the leading end section in a state where the elevator is lying; 
         FIG. 15  is a front view illustrating the peripheral portion of the elevator in the leading end section in a state where the elevator rises most; and 
         FIG. 16  is a top view illustrating a peripheral portion of the elevator in another embodiment in a state where the elevator is lying. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferable embodiments of the present invention will be described in detail with reference to accompanying drawings. 
       FIG. 1  is a general structural view of an ultrasound inspection system  1 . 
     The ultrasound inspection system  1  includes an ultrasound endoscope  2  that takes an endoscope image and an ultrasound image in the body, an ultrasound processor unit  3  that generates the ultrasound image, an endoscope processor unit  4  that generates the endoscope image, a light source device  5  that supplies illumination light to the ultrasound endoscope  2  to illuminate the inside of the body, and a monitor  6  that displays the endoscope image and the ultrasound image. 
     The ultrasound endoscope  2  is a convex type ultrasound endoscope, and includes an insertion section  10  to be inserted into the body, the insertion section  10  having a leading end and a base end, an operation section  11  provided at the base end of the insertion section  10 , and a universal cord  14  whose base end is connected to the operation section  11 . The universal cord  14  is provided at its leading end with connectors  14 A,  14 B, and  14 C to connect the ultrasound endoscope  2  to the ultrasound processor unit  3 , the endoscope processor unit  4 , and the light source device  5 , respectively. 
     The insertion section  10  includes a flexible portion  15 , a curvature portion  16 , and a leading end section  20 , which are provided in the order from the base end to the leading end. 
     The flexible portion  15  has flexibility to curve in any direction along an insertion route of the insertion section  10 . The curvature portion  16  curves in each of directions of up and down, and right and left, by operating an angle knob  21  of the operation section  11 . 
     The leading end section  20  is provided at its leading end with an ultrasound observation section  100  that receives and transmits ultrasound, and converts received ultrasound into an ultrasound signal being an electric signal to output the ultrasound signal. The ultrasound signal outputted by the ultrasound observation section  100  is transmitted to the ultrasound processor unit  3  connected through the universal cord  14 . Then, the ultrasound processor unit  3  generates a tomographic image, as an ultrasound image, of cellular tissue existing in a depth direction of a body wall portion irradiated with ultrasound. 
     In addition, the leading end section  20  includes an optical observation section that takes an image of an observed site in the body, and an illumination section that irradiates the observed site with illumination light, each of which is provided at a portion closer to the base end than the ultrasound observation section  100 . The image taken by the optical observation section is transmitted to the endoscope processor unit  4  connected through the universal cord  14 , as an observation image (endoscope image), and the illumination light emitted by the illumination section is propagated from the light source device  5  connected through the universal cord  14  by passing through a light guide in the ultrasound endoscope  2 . 
     Further, the leading end section  20  includes a treatment tool leading section  41  that is provided at a portion closer to the base end than the ultrasound observation section  100 . The treatment tool leading section  41  allows a treatment tool  150  inserted into the treatment tool insertion channel in the insertion section  10  from a treatment tool inlet  25  of the operation section  11  to be led outside the insertion section  10 . The treatment tool leading section  41  is provided with an elevator  50  described later to adjust a leading direction of the treatment tool  150 . 
     Next, structure of the leading end section  20  will be described.  FIGS. 2 and 3  are a perspective view and a plan view (top view), respectively, illustrating an appearance of the leading end section  20 . 
     The leading end section  20  includes a leading end body  30  that is provided at the leading end of the insertion section  10  to form an outer wall and an inner partition wall of the leading end section  20 , a plurality of accommodation sections defined by the leading end body  30 , and various components accommodated and held in the accommodation sections. 
     While detailed description is omitted, a part of the leading end body  30  is detachable as a separate block, and thus each of the components can be assembled in a predetermined accommodation section while the separate block is detached. Attaching the separate block to the leading end body  30  after each of the components is assembled in the corresponding accommodation section allows each of the components to be accommodated and held in the corresponding accommodation section to be fixed to the leading end section  20 . 
     The leading end body  30  is formed of insulating material with insulation, for example, resin material, such as plastic like methacrylate resin and polycarbonate. 
     The leading end section  20 , as illustrated in  FIGS. 2 and 3 , includes a base section  32  on a base end side, and an extension section  33  extending from the base section  32  to a leading end side. 
     The extension section  33  is provided with the ultrasound observation section  100  described above on an upper face side of the extension section  33 . The ultrasound observation section  100  includes a convex type ultrasound transducer  102  in which a large number of ultrasound vibrators for receiving and transmitting ultrasound are arranged in a convex shape. 
     When an axial direction of the insertion section  10  is viewed from the base end side of the insertion section  10  to the leading end side thereof, a direction in which the ultrasound observation section  100  and the treatment tool leading section  41  are disposed is referred to as “upper”, and a direction opposite to the direction is referred to as “lower”, in a direction perpendicular to the axis of the insertion section  10 , for terms that indicate up, down, left and right directions. 
     The base section  32  includes a left inclined face  40 L and a right inclined face  40 R, extending toward the leading end obliquely upward, and a recessed treatment tool leading section  41  provided in a central portion between the left inclined face  40 L and the right inclined face  40 R. 
     The left inclined face  40 L includes an observation window  42 , an illumination window  43 L, and an air-and-water supply nozzle  44 . The right inclined face  40 R includes an illumination window  43 R. 
     The observation window  42  is provided to acquire an optical image of a subject, and is a component of the optical observation section described above that acquires an image of an observed site as an observation image. In the base section  32  behind the observation window  42 , there is accommodated and disposed an imaging system unit that is a component of the optical observation section, and is formed by integrally assembling an imaging optical system and a solid imaging element. The imaging system unit is electrically connected to the endoscope processor unit  4  connected to the universal cord  14 . 
     The illumination windows  43 R and  43 L each are a component of the illumination section described above that irradiates an observed site with illumination light. In the base section  32  behind the illumination windows  43 R and  43 L, there is accommodated and disposed a light emission section that is a component of the illumination section, and emits illumination light through the illumination windows  43 R and  43 L. The light emission section is optically connected to the light source device  5  connected to the universal cord  14 , through the light guide. 
     The air-and-water supply nozzle  44  sprays water and air to the observation window  42  by operating an air-and-water supply button  22  (refer to  FIG. 1 ) of the operation section  11  to perform cleaning of the observation window  42  and the like. 
     In the treatment tool leading section  41 , the elevator  50  is disposed, and an elevator accommodation groove  45  having an opening  45 A in a side face (upper side) of the leading end body  30  is formed as a slit-like elevator accommodation space in which the elevator  50  is disposed, the elevator accommodation groove  45  being provided on its base end side with a treatment tool insertion hole  55 A. 
     The treatment tool insertion hole  55 A communicates with the treatment tool inlet  25  (refer to  FIG. 1 ) of the operation section  11  through the treatment tool insertion channel (pipe conduit) formed through the inside of the insertion section  10 . Thus, the treatment tool inserted from the treatment tool inlet  25  is guided from the treatment tool insertion hole  55 A to the elevator accommodation groove  45 . Then, the elevator  50  in the elevator accommodation groove  45  bends a leading direction (leading angle) of the treatment tool so that the treatment tool is led toward a side (upper side) of the insertion section  10  from the treatment tool leading section  41 . 
     The treatment tool insertion channel is also coupled to a suction channel, and body fluid or the like is sucked through the treatment tool insertion hole  55 A by operating a suction button  23  (refer to  FIG. 1 ) of the operation section  11 . 
     The elevator  50  includes a guide face  50 A that is rotatable provided around a rotation axis in an axial direction including a component of a direction orthogonal to a longitudinal axis of the insertion section  10 , and that is a treatment tool guiding face for guiding the treatment tool led from the treatment tool insertion channel. The guide face  50 A is formed in a concave shape (arc-like shape) in an upper face of the elevator  50  so as to curve upward from a base end side of the leading end section  20  toward a leading end side thereof. 
     The treatment tool led to the elevator accommodation groove  45  through the treatment tool insertion hole  55 A curves upward with respect to an axial direction (longitudinal axis direction of the insertion section  10 ) of the leading end section  20  along the guide face  50 A to be led outside through the opening  45 A on an upper side of the elevator accommodation groove  45 , the opening  45 A being a treatment tool outlet. 
     Since the elevator  50  is configured to rise and lie by operating a raising operation lever  24  (refer to  FIG. 1 ) of the operation section  11 , adjusting a raising angle from a lying state by allowing the elevator  50  to rise or lie enables adjustment of a leading direction (leading angle) of the treatment tool to be led from the treatment tool leading section  41 . 
     Subsequently, there will be described an elevator assembly  49  that supports and drives the elevator  50  in the leading end section  20 . 
       FIG. 4  is a perspective view illustrating the elevator assembly  49  viewed from the left side,  FIG. 5  is a perspective view illustrating the whole of the elevator assembly  49  viewed from the right side, and  FIG. 6  is an exploded perspective view of the elevator assembly  49 .  FIG. 7  is a sectional view viewed from a direction of arrows  7 - 7  in  FIG. 3 . 
     The elevator assembly  49  is integrally assembled as illustrated in  FIGS. 4 and 5 , and is accommodated and held in a predetermined accommodation section of the leading end body  30  to be fixed in the leading end section  20  as illustrated in  FIG. 7 . 
     As illustrated in  FIGS. 4 to 7 , the elevator assembly  49  is an elevator accommodation case, and includes an assembly body  51  that supports components, the elevator  50  supported by the assembly body  51 , a raising lever  52  that allows the elevator  50  to rise and lie, and the like. In  FIGS. 5 and 6 , there is omitted a lid member  56 B (refer to  FIG. 7 ) with which a lever accommodation space  56 A for accommodating the raising lever  52  is covered. 
     The assembly body  51 , as illustrated in  FIGS. 4 to 6 , includes a base portion  53  that constitutes a lower portion of the assembly body  51 , a partition  54  that constitutes an upper right portion of the assembly body  51  and serves as a partition wall between the elevator  50  and the raising lever  52 , along with the base portion  53 , and a treatment tool insertion portion  55  that constitutes a base end portion. While these components are integrally formed, separated components may be coupled to each other. 
     The base portion  53  is disposed below the elevator accommodation groove  45  with respect to an area of the elevator accommodation groove  45  in a state where the base portion  53  is accommodated in the leading end section  20  (the predetermined accommodation section of the leading end body  30 ) as the elevator assembly  49  as illustrated in  FIGS. 2 and 3  (and  FIG. 7 ). 
     In an area along a left face of the base portion  53 , there is formed a recessed portion  53 B for rotatable accommodating a support portion  61  of the elevator  50 , the recessed portion  53 B having an opened left face. 
     The partition  54  extends upward at a position along a right edge of a top face  53 A of the base portion  53 , and a left face  54 A of the partition  54  constitutes a right wall face of the elevator accommodation groove  45 . 
     The leading end body  30  (a partition wall  30 A in  FIG. 7 ) constitutes a left wall face of the elevator accommodation groove  45 . 
     A lever accommodation section  56  is provided in an area along the base portion  53  and a right face of the partition  54  (refer to  FIG. 5 ) to constitute the lever accommodation space  56 A for rotatable accommodating the raising lever  52 . The lever accommodation space  56 A is provided with a cylindrical bearing hole  57  (refer to  FIGS. 6  and  7 ) that penetrates to the recessed portion  53 B of the base portion  53  to rotatable support the elevator  50  and the raising lever  52 . 
     The treatment tool insertion portion  55  is connected to a base end side of each of the base portion  53  and the partition  54 , and the treatment tool insertion portion  55  is disposed on a base end side of the elevator accommodation groove  45 . 
     The treatment tool insertion portion  55  is provided with the treatment tool insertion hole  55 A that opens toward the elevator accommodation groove  45 . A pipe conduit member  110  constituting the treatment tool insertion channel is connected to a base end side of the treatment tool insertion portion  55  to allow the treatment tool insertion hole  55 A to communicate with the treatment tool insertion channel. 
     The assembly body  51  includes a partition wall between the elevator  50  and the raising lever  52 , the partition wall being composed of the base portion  53  and the partition  54 , and the partition wall is provided with the bearing hole  57  for supporting the elevator  50  and the raising lever  52 . The assembly body  51  also includes an open portion  58  opened toward an opposite side to the partition wall with respect to the elevator  50 , and the open portion  58  is formed in an area including the elevator  50  as viewed from an axial direction of the bearing hole  57 . 
     In  FIG. 7 , reference numeral  120  designates the imaging optical system constituting the optical observation section, and in the leading end section  20 , the accommodation section for accommodating the elevator assembly  49  and an accommodation section for accommodating an imaging-system assembly in which components of the optical observation section are integrally assembled are separated by the partition wall  30 A being a part of the leading end body  30 . That is, when viewed from the leading end side along the longitudinal axis of the insertion section  10 , the optical observation section is provided on a side where the open portion  58  of the elevator assembly  49  is provided. In a state where the elevator assembly  49  and the optical observation section are assembled in the leading end body  30 , the optical observation section is provided in an area overlapping with at least an elevator rotation shaft portion  62  (described later) of the elevator  50  as viewed from an axial direction of the bearing hole  57 . 
     The elevator  50  includes the elevator body  60  with a bilaterally symmetrical shape that is provided with the arc-like guide face  50 A as described above, the support portion  61  that extends downward from a base end portion of the elevator body  60  and has a lateral width less than that of the elevator body  60 , and the elevator rotation shaft portion  62  that is formed to project from the support portion  61  in a direction including a component of a direction orthogonal to the longitudinal axis of the insertion section  10 , the elevator rotation shaft portion  62  being formed as a first rotation shaft portion. 
     The elevator rotation shaft portion  62  is inserted into the bearing hole  57  of the assembly body  51  from a recessed portion  53 B side, and is rotatable supported in the bearing hole  57 . 
     Accordingly, the support portion  61  of the elevator  50  is accommodated in the recessed portion  53 B to be rotatable around an axis of the elevator rotation shaft portion  62 , or around an axis of the bearing hole  57 . 
     The elevator body  60  is accommodated at a position facing the treatment tool insertion hole  55 A of the elevator accommodation groove  45  to be rotatable around the axis of the bearing hole  57 , or to be able to rise and lie. 
     The raising lever  52  is formed in the shape of an elongated plate, and includes a lever rotation shaft portion  80  as a second rotation shaft portion that projects from one end side (base end side) of the raising lever  52  in a longitudinal direction. At the other end (leading end side), a wire coupling portion  81  to which an operation wire  113  is to be coupled is formed. 
     The lever rotation shaft portion  80  is inserted into the bearing hole  57  of the assembly body  51  from the lever accommodation space  56 A side to be coupled to the elevator rotation shaft portion  62  of the elevator  50 , and is fixed to the elevator rotation shaft portion  62  with a screw  90 . 
     Accordingly, the lever rotation shaft portion  80  is formed coaxially with the elevator rotation shaft portion  62  to be coupled to the elevator rotation shaft portion  62 , and thus the lever rotation shaft portion  80  is rotatably supported in the bearing hole  57  to be rotated integrally with the elevator rotation shaft portion  62 . Details of a coupling mechanism of the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  will be described later. 
     The raising lever  52  is accommodated in the lever accommodation space  56 A to be rotatable around an axis of the lever rotation shaft portion  80 , or around the axis of the bearing hole  57 . 
     Meanwhile, as illustrated in  FIG. 5 , a control cable  112  including a guide tube  114  and the operation wire  113  inserted into the guide tube  114  is connected to a base end side of the lever accommodation section  56  in a base end portion of the treatment tool insertion portion  55  of the assembly body  51 . One end (base end) of the operation wire  113  is coupled to the raising operation lever  24  of the operation section  11 , and the operation wire  113  is pushed and pulled by operating the raising operation lever  24 . The other end (leading end) of the operation wire  113  is inserted into the lever accommodation space  56 A to be coupled to the wire coupling portion  81  of the raising lever  52  through a connection member  116 . 
     According to the elevator assembly  49  described above, when the operation wire  113  is pushed or pulled by operating the raising operation lever  24 , the raising lever  52  turns around the axis of the lever rotation shaft portion  80 . Then, the elevator rotation shaft portion  62  turns in conjunction with turning of the raising lever  52  so that the elevator  50  rises and lies. 
     While an aspect of a transfer member for transferring displacement generated by the operation section  11  to the raising lever  52  is the operation wire  113  that is provided from the operation section  11  to the leading end body  30  through the insertion section  10 , another aspect is available. 
     Subsequently, a coupling mechanism for coupling the elevator  50  and the raising lever  52  to each other (hereinafter, referred to as an elevator-lever coupling mechanism) will be described. 
       FIG. 8  is a front view of the elevator  50  and the raising lever  52  in the elevator-lever coupling mechanism of the present embodiment, and  FIG. 9  is a sectional view of the elevator-lever coupling mechanism of the present embodiment in the elevator assembly  49 , taken along a plane including the axis of the elevator rotation shaft portion  62  (bearing hole  57 ), the plane being perpendicular to an axis of the leading end section  20  (longitudinal axis of the insertion section  10 ). 
     As illustrated in the (A) portion of  FIGS. 8 and 9 , the elevator rotation shaft portion  62  of the elevator  50  projects from the support portion  61 , and includes a large diameter portion  63 , a small diameter portion  64 , and a rotation regulation portion  65  in order from the support portion  61 . 
     The large diameter portion  63  is formed like a column, and has an outer diameter that is substantially equal to an inner diameter of the bearing hole  57  of the assembly body  51 . 
     The small diameter portion  64  is provided adjacent to the large diameter portion  63  on a side facing the raising lever  52 , and is formed like a column. In addition, the small diameter portion  64  has an outer diameter smaller than the outer diameter of the large diameter portion  63 , and is provided with a seal member  92  (refer to  FIG. 9 ) that is fit around the small diameter portion  64 . 
     The rotation regulation portion  65  extends from the small diameter portion  64 , and is formed like a quadrangular prism. In addition, the rotation regulation portion  65  like a quadrangular prism has a diagonal length (diameter of a circumscribed cylinder) smaller than the outer diameter of the small diameter portion  64 . 
     In addition, a screw hole  66  (refer to  FIG. 9 ) is formed from a leading end face of the rotation regulation portion  65  toward an opposite face thereof, along an axis of the elevator rotation shaft portion  62 . 
     Meanwhile, as illustrated in the (B) portion of  FIGS. 8 and 9 , the lever rotation shaft portion  80  of the raising lever  52  is formed like a column, and has an outer diameter that is substantially equal to the inner diameter of the bearing hole  57  of the assembly body  51 . 
     A fitting hole  83  like a quadrangular prism is formed in a leading end face of the lever rotation shaft portion  80  toward an opposite face thereof along the axis of the lever rotation shaft portion  80  so that the rotation regulation portion  65  of the elevator rotation shaft portion  62  can be fitted into the fitting hole  83  substantially without a gap. 
     The fitting hole  83  has an axial length that is substantially equal to an axial length of the rotation regulation portion  65 . 
     In addition, a screw insertion hole  84  having a diameter smaller than a diagonal length of the fitting hole  83  is formed in a bottom face of the fitting hole  83  toward a face opposite to the bottom face, along the axis of the lever rotation shaft portion  80 . Then, a counterbore hole  85  having an inner diameter larger than an inner diameter of the screw insertion hole  84  is formed while communicating with the screw insertion hole  84 , and penetrates to a face opposite to the leading end face of the lever rotation shaft portion  80 . 
     The elevator  50  and the raising lever  52  in the elevator-lever coupling mechanism of a first embodiment described above allow the elevator rotation shaft portion  62  of the elevator  50  to be inserted from the recessed portion  53 B in the assembly body  51  of the elevator assembly  49 , and allow the lever rotation shaft portion  80  of the raising lever  52  to be inserted into the bearing hole  57  from the lever accommodation space  56 A opposite to the recessed portion  53 B. 
     The rotation regulation portion  65  of the elevator rotation shaft portion  62  is fitted into the fitting hole  83  of the lever rotation shaft portion  80 , and the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  are coupled to each other at a predetermined rotation angle. Then, the screw  90  with a head part is inserted into the counterbore hole  85  of the raising lever  52  to be screwed into the screw hole  66  of the elevator rotation shaft portion  62 . 
     As a result, the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  are coupled to each other. 
     In a state where the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  are coupled to each other as described above, the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  are fixed while the leading end face of the lever rotation shaft portion  80  is in contact with a stepped face formed in a step between the small diameter portion  64  and the rotation regulation portion  65  of the elevator rotation shaft portion  62 . Then, a seal groove  91  along a circumferential direction, as a position regulation groove of the seal member  92 , is formed between a first regulation face that is a stepped face formed in a step between the large diameter portion  63  and the small diameter portion  64  of the elevator rotation shaft portion  62 , and a second regulation face that is the leading end face of the lever rotation shaft portion  80  and faces the first regulation face. The first regulation face and the second regulation face each have a normal direction that is an axial direction of the elevator rotation shaft portion  62 . 
     Meanwhile, before the elevator rotation shaft portion  62  is inserted into the bearing hole  57  of the assembly body  51 , the seal member  92  such as an O-ring is fitted around an outer peripheral surface of the small diameter portion  64 . Thus, when the elevator rotation shaft portion  62  is inserted into the bearing hole  57  to couple the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  to each other, the seal groove  91  serves as a positioning portion for positioning the seal member  92  in the axial direction of the bearing hole  57  to allow the seal member  92  to be disposed in the seal groove  91  while the seal member  92  is positioned. Then, the seal member  92  is brought into close contact with an internal wall face of the bearing hole  57 . 
     Accordingly, the lever accommodation space  56 A of the lever accommodation section  56  is airtightly sealed from the elevator accommodation groove  45  to prevent blood, water, or the like, from entering the lever accommodation space  56 A from the elevator accommodation groove  45 . 
     In addition, since a coupled position of the elevator rotation shaft portion  62  and the lever rotation shaft portion  80  is positioned closer to the raising lever  52  than the seal member  92 , blood, water, or the like cannot enter the lever accommodation space  56 A from the elevator accommodation groove  45  or a gap in a coupling portion of the elevator rotation shaft portion  62  and the lever rotation shaft portion  80 . Further, there is no coupling portion between members through which blood, water, or the like enters, in a portion closer to the elevator accommodation groove  45  than the seal member  92 . 
     The elevator accommodation groove  45  has the open portion  58  on a side opposite to the partition wall of the assembly body  51  with respect to the elevator  50 , and thus when the elevator assembly  49  is assembled, the elevator  50  can be inserted into the elevator accommodation groove  45  from the open portion  58  to be disposed, and the elevator rotation shaft portion  62  can be inserted into the bearing hole  57  from the open portion  58  to be disposed. Thus, no extra space is needed to dispose the elevator  50  in the elevator accommodation groove  45 , and a width of the elevator accommodation groove  45  can be substantially equal to a width of the elevator body  60 , whereby the leading end section  20  is prevented from increasing in size. 
     Instead of the seal groove  91  of the present embodiment, as the seal groove for disposing the seal member  92 , for example, a groove in a circumferential direction may be formed in the elevator rotation shaft portion  62  or the lever rotation shaft portion  80 , or a groove in a circumferential direction is formed in the internal wall face of the bearing hole  57 , and the groove may serve as a seal groove (position regulation groove). 
     Unfortunately, since it is not easy to form a groove in the circumferential direction in the elevator rotation shaft portion  62  formed integrally with the elevator body  60  and the like, or in the bearing hole  57 , forming the seal groove  91  by combination with lever rotation shaft portion  80  like the present embodiment enables the elevator  50  and the like to be easily worked. 
     While the raising lever  52  has the lever rotation shaft portion  80  as the second rotation shaft portion in the elevator-lever coupling mechanism, the raising lever  52  may not have the lever rotation shaft portion  80 . In this case, the elevator rotation shaft portion  62  of the elevator  50  is configured to be directly coupled to a body portion (plate-shaped portion) of the raising lever  52 . 
     The elevator-lever coupling mechanism is not limited to the present embodiment, and can use appropriate structure. 
     Next, the elevator  50  and its peripheral components for improving easiness of cleaning operation of the elevator  50  will be described in detail. 
       FIGS. 10 and 11  are enlarged perspective and front views, respectively, illustrating the elevator body  60  of the elevator  50 . The front view of  FIG. 11  illustrates the elevator body  60  viewed from a direction in which the elevator body  60  is the base end of the leading end section  20 . 
     As illustrated in these drawings, the elevator body  60  has a bilaterally symmetrical shape, and includes a proximal end portion  70 , a distal end portion  71  that has a distance from the axis of the elevator rotation shaft portion  62  (hereinafter referred to as a rotation axis of the elevator  50 , or simply a rotation axis) in a radial direction of the rotation axis, the distance being more than a distance therefrom to the proximal end portion  70 , the guide face  50 A provided between the proximal end portion  70  and the distal end portion  71 , and elevator side faces  72 R and  72 L each of which is adjacent to the guide face  50 A, and has a normal direction to be a direction including a component of a direction of the rotation axis. 
     The elevator body  60  also includes a wide body portion  73  on its distal end portion  71  side, and a narrow body portion  74  that is formed closer to the proximal end portion  70  than the wide body portion  73 , and has a width in the direction of the rotation axis less than that of the wide body portion  73 . 
     In addition, the wide body portion  73  of the elevator body  60  has rounded cross sectional and longitudinal sectional shapes with respect to the direction of the rotation axis. In this case, the entire section may be rounded, or may have a shape chamfered to a level without an acute edge. Such a shape may not damage the inside of the body regardless of a position of the elevator  50 . 
       FIGS. 12 and 13  each are a sectional view of the leading end section  20  with respect to a direction orthogonal to the direction of the rotation axis, the sectional view being taken along a line passing through the center of the elevator body  60  in its width direction (the direction of the rotation axis). 
       FIG. 12  illustrates a state where the elevator  50  is lying, and  FIG. 13  illustrates a state where the elevator  50  rises most. 
       FIG. 14  is a top view illustrating a peripheral portion of the elevator  50  in the leading end section  20  in a state where the elevator  50  is lying, and  FIG. 15  is a front view illustrating the peripheral portion of the elevator  50  in the leading end section  20  in a state where the elevator  50  rises most. A state where the elevator  50  rises as illustrated in  FIGS. 13 and 15  represents the state where the elevator  50  rises most, however, the elevator  50  may not necessarily rise most. 
     As illustrated in  FIG. 14 , the elevator accommodation groove  45  includes the elevator side faces  72 R and  72 L, and the elevator accommodation groove side faces  47 R and  47 L facing each other across the gap portions  46 R and  46 L, as right and left side wall faces. 
     In a state where the elevator  50  is lying as illustrated in  FIGS. 12 and 14 , the whole of the elevator body  60  is accommodated in the elevator accommodation groove  45 . In the present embodiment, while the elevator accommodation groove side faces  47 R and  47 L are formed along a plane, the elevator body  60  includes the wide body portion  73  and the narrow body portion  74 . Thus, in a state where the elevator  50  is lying, the gap portions  46 R and  46 L respectively include: narrow gap portions  46 RF and  46 LF formed between distal end portion side faces  72 RF and  72 LF in the elevator side faces  72 R and  72 L, positioned on the distal end portion  71  side, and the elevator accommodation groove side faces  47 R and  47 L; and wide gap portions  46 RN and  46 LN formed between proximal end portion side faces  72 RN and  72 LN in the elevator side faces  72 R and  72 L, positioned closer to the proximal end portion  70  than the distal end portion side faces  72 RF and  72 LF, and the elevator accommodation groove side faces  47 R and  47 L, the wide gap portions  46 RN and  46 LN each having a width in the direction of the rotation axis more than that of each of the narrow gap portions  46 RF and  46 LF. 
     Thus, a treatment tool led to the elevator accommodation groove  45  from the treatment tool insertion hole  55 A of the treatment tool leading section  41  is prevented from dropping into the gap portions  46 R and  46 L each in a side of the elevator body  60  by the wide body portion  73  of the elevator body  60 , or by the narrow gap portions  46 RF and  46 LF. 
     Meanwhile, in a state where the elevator  50  rises most as illustrated in  FIGS. 13 and 15 , the wide body portion  73  of the elevator body  60  projects outside through the opening  45 A of the elevator accommodation groove  45 . Since the wide body portion  73  of the elevator body  60  has a rounded shape, no special attention is needed even if the wide body portion  73  projects outside through the opening  45 A. 
     The elevator accommodation groove  45  includes leading portions  48 R and  48 L that are formed in a rounded shape in cross section by chamfering an edge of the opening  45 A of the elevator accommodation groove  45 . The leading portions  48 R and  48 L each increase in width in the direction of the rotation axis toward the opening  45 A. 
     Since a size of a chamfer of each of the leading portions  48 R and  48 L is twice or more a wire diameter of each of bristles of a cleaning brush to be used for cleaning the elevator  50 , the bristles of the cleaning brush are led to a gap between the elevator body  60  and each of the elevator accommodation groove side faces  47 R and  47 L. 
     Since a back face  60 B opposite to the guide face  50 A of the elevator body  60  has an rounded shape in longitudinal section with respect to the direction of the rotation axis, the bristles of the cleaning brush are led to a gap between the back face  60 B and each of the elevator accommodation groove side faces  47 R and  47 L. 
     Thus, time and effort required for cleaning operation of the elevator  50  is reduced when the elevator  50  (and its peripheral portion) is cleaned with a cleaning brush, because raising the elevator  50  exposes the side faces (distal end portion side faces  72 RF and  72 LF) of the wide body portion  73  of the elevator body  60 , and bristles of the cleaning brush is easily led into a gap between the elevator body  60  and each of the elevator accommodation groove side faces  47 R and  47 L, the gap being difficult to be cleaned. 
     In the embodiment describe above, while the narrow gap portion  46 RF and  46 LF, and the wide gap portions  46 RN and  46 LN are acquired by using the wide body portion  73  and the narrow body portion  74  of the elevator body  60  in a state where the elevator  50  is lying (refer to  FIG. 14 ), structure is not limited to the above. 
     For example, as illustrated in  FIG. 16 , while the elevator side faces  72 R and  72 L is formed along a plane, the elevator accommodation groove  45  may include a narrow groove  200  provided on a distal end portion  71  side of the elevator  50 , and a wide groove  202  that is provided closer to the proximal end portion  70  than the narrow groove  200 , and has a width in the direction of the rotation axis more than that of the narrow groove  200 , in a state where the elevator  50  is lying. 
     Accordingly, as with the embodiment described above, the gap portions  46 R and  46 L respectively include the narrow gap portions  46 RF and  46 LF on their leading end sides, and the wide gap portions  46 RN and  46 LN on their base end sides. The narrow groove  200  is adjacent to the narrow gap portions  46 RF and  46 LF, and the wide groove  202  is adjacent to the wide gap portions  46 RN and  46 LN. 
     In the embodiment described above, while there is described the case where the present invention is applied to the ultrasound endoscope  2  including the ultrasound observation section  100  and the elevator  50  in the leading end section  20 , the present invention can be applied to even an endoscope without an ultrasound observation section, such as a side-viewing endoscope including an elevator.