Patent Publication Number: US-2009227842-A1

Title: Angle wire fixing structure of endoscope

Description:
BACKGROUND OF THE INVENTION 
     The disclosure of Japanese Patent Applications Nos. 2,008-057146 and 2008-057147, filed on Mar. 7, 2008, including its specification, claims and drawings, is incorporated herein by reference in its entirety. 
     1. Field of the Invention 
     The present invention relates to an angle wire fixing structure for fixing an angle wire that effects a bending operation of a distal end portion and an angle portion of an endoscope to an angle ring at a distal end side of an endoscope. 
     2. Description of the Related Art 
     The endoscope comprises a distal end portion in which an objective optical system is arranged, an angle portion (bending portion) including an angle ring in an exterior body, and an operation portion having a bending operation knob and the like, and a plurality of wires are disposed from a wire winding-up portion coupled to the bending operation knob to a distal-end ring of the angle ring. By executing a pulling operation of the plurality of wires with the bending operation knob, the distal end portion and the angle portion can be bent vertically and horizontally. 
       FIG. 14  illustrates a configuration of the distal end side of the conventional endoscope, and as shown in the figure, the distal end side of an endoscope  1  is constructed so that an angle ring  3  is attached on a distal-end portion main body  2 . The angle ring  3  is a ring coupled body constituting a multi-nodal mechanism by pivotally attaching a large number of rings alternately in vertical and horizontal directions, and a wire  5  is attached and fixed to a attaching portion  4  provided at the distal-end ring  3 . That is, the attaching portion  4  has a through hole, for example, and the wire  5  is fixed by inserting the wire  5  through the through hole and bending its distal end and then, by brazing or soldering the through hole portion. 
     SUMMARY OF THE INVENTION 
     However, in the conventional endoscope, as described in  FIG. 14 , the wire  5  for the bending operation of the distal end portion and the angle portion is fixed by brazing or soldering to the angle ring  3 , which causes a problem that replacement of the wire  5  is difficult. That is, in the wire  5  of the endoscope for which a diameter is to be reduced, the diameter is small and its attaching is precise, which might cause cut-off or removal at the attaching portion. In this case, in the replacement and repair of the wire  5  in  FIG. 14 , it is difficult to remove only the wire  5  for replacement but the entire angle portion including the angle ring  3  should be replaced at the same time, which makes the repair cumbersome. Also, since the entire angle portion is expensive, the repair cost is high, which is another problem. 
     Paying attention to these problems, conventional arts in the following Patent Literature 1 to 3 are proposed. Patent Literature 1 (Japanese Utility Model Laid-Open No. 3-78504) is configured such that a locking hole and a slit are provided at a locking tube arranged between a distal end portion and a distal end portion of a bending portion constituting ring, and a fixing member of a wire is inserted through the slit up to the locking hole so as to fit and lock the fixing member at the locking hole. However, with Patent Literature 1, there is a possibility that the wire fixing member is moved in an outer circumferential direction, for example, and is removed from the locking hole. 
     Patent Literature 2 (Japanese Patent Laid-Open No. 62-186836) has a configuration in which a groove is formed on an outer circumference of a distal-end portion main body of an endoscope, a stopper portion at a distal end of a wire is fitted in this groove, and the outside thereof is covered by a sheath tube. Since a lens assembly, a CCD and the like for an observation optical system are arranged at the distal-end portion main body in general, there is no allowance of space in the inner circumference portion, and it is difficult to fix the wire on the inner circumference side of the distal-end portion main body. Also, the distal-end portion main body is constituted by solid portions, and a hole for arranging the observation optical system, a light guide and the like is worked afterwards. Thus, if the wire is fixed on the inner circumference, a hole for the wire needs to be worked, and a structure for fixing is further made complicated. Therefore, in order to fix the wire distal end to the distal-end portion main body, a structure to fix it to the outer circumference is generally used as in Patent Literature 2. 
     However, since in Patent Literature 2, a groove is formed on the outer circumference of the distal-end portion main body, a thickness for the groove is needed and the diameter of the distal-end portion main body can not be reduced, and narrowing of the diameter of the endoscope is prevented. On the other hand, since the inside of the angle ring is hollow for the entirety, a space other than the space for arranging the contents such as light guide, electric cables and the like becomes a dead space, which has some allowances as compared with the distal-end portion main body, and if the wire is fixed on the angle ring side, it can be fixed on the inner circumference side and that does not enlarge the outer circumference. Thus, the wire is preferably fixed on the angle ring side. 
     Patent Literature 3 (Japanese Patent Laid-Open No. 59-228620) is configured such that an emboss portion using a shape memory metal is provided at a nodal ring constituting a bending portion, and a wire is attached at the time of transition of a high-temperature phase of the shape memory metal while the wire is removed at the time of transition of a low-temperature phase. However, in Patent Literature 3, since the shape memory metal is used, transition work of the high-temperature phase and the low-temperature phase is complicated, and a manufacturing costs and a repair cost are high. 
     The present invention was made in view of the above problems and has an object to provide an angle wire fixing structure of an endoscope in which fixing in attaching a wire is surely carried out if the wire is detachable with respect to an angle ring and moreover, the wire is not largely moved at an attaching and fixing portion in a distal-end direction, wire replacement is facilitated, a repair cost can be reduced, and narrowing of the diameter of the endoscope is not prevented. 
     In order to achieve the above object, an angle wire fixing structure of an endoscope according to the present invention comprises a fixing member (stopper) to which a wire for bending an angle portion is attached and in which a groove is formed on a side face thereof and an attaching hole (opening) formed on a side face of an angle ring and having a locking portion (notched portion) by which the groove of the fixing member is locked in a state where the wire is arranged on an inner circumferential face side of the angle ring, characterized in that the fixing member is detachably attached and fixed to the attaching hole. 
     The attaching hole is formed as a T-shaped hole with a T-shaped perpendicular portion serving as the locking portion, and the grooves formed on both side faces of the fixing member can be locked by the T-shaped perpendicular portion. 
     According to the above configuration, the grooves are formed on both sides of the fixing member, for example, and the T-shaped attaching hole with the T-shaped perpendicular portion serving as the locking portion is provided in the angle ring, and by inserting the fixing member from a T-shaped horizontal portion to the T-shaped perpendicular locking portion of the attaching hole and by locking the grooves on the both sides by the locking portion, the fixing member is fixed to the attaching hole. 
     According to the present invention as above, even if the wire is made detachable with respect to the angle ring, there is an effect that fixing in attaching of the wire can be surely carried out, and thus, wire replacement is facilitated, and the repair cost can be lowered. Also, since the wire is not attached on the distal-end portion main body of the endoscope, there is an advantage that narrowing of the diameter of the endoscope is not prevented. 
     In the fixing member, a screw hole is formed, and a screw can be inserted through the screw hole and the attaching hole so as to screw the fixing member into the distal-end portion main body. According to this, the fixed state can be made firmer by the screwing. 
     In the locking portion by which the groove of the fixing member is locked, a projection portion projecting in the perpendicular direction from the side face of the angle ring may be provided. This has an advantage that the locking portion at the attaching hole provided at the angle ring can be prevented from being widened by a frequent pulling operation of the wire. 
     Also, a portion of the attaching hole may be recessed on the inward side of the angle ring so that the outer circumference of the fixing member attached to the attaching hole substantially matches an outer circumferential circle of the angle ring. According to this, there are advantages that increase in the outer circumference of the attaching portion of the fixing member in the angle ring can be prevented, and the narrowing of the diameter of the endoscope is not obstructed. 
     Also, the angle wire fixing structure of the endoscope of another invention is provided with a wire having a small body (small mass) for locking formed at a distal end and arranged on an inner circumferential face side of an angle ring for bending an angle portion, a wire fixing portion provided for attaching a wire on the angle ring and having a locking hole for detachably locking the small body for locking formed, and a distal-end portion main body fitted and connected to the angle ring of the angle portion and having a rear end in contact with or in proximate to a distal end portion of the small body for locking, the small body for locking being arranged in a locking hole of the wire fixing portion, wherein the small body for locking is detachably attached on the locking hole of the wire fixing portion, and an operation of the small body for locking is regulated by the rear end of the distal-end portion main body. 
     According to the configuration of the above another invention, the wire fixing portion is integrally or detachably attached to a side face of the angle ring, the small body of the wire distal end is inserted into and locked by the locking hole (two-staged hole) of the wire fixing portion, and then, the distal-end portion main body is fitted with the angle ring and arranged so that the rear end of the distal-end portion main body is in contact with or in proximate to the distal end portion of the small body and the wire is attached and fixed to the angle ring. 
     The wire fixing portion may be constituted by the fixing member to which wire is attached and in which the locking hole is formed and the groove is formed on the side face and by the attaching hole formed on the side face of the angle ring and having the locking portion by which the groove of the fixing member is locked in a state where the wire is arranged on the inner circumferential face side of the angle ring, and the wire fixing portion may be constructed so that the fixing member is detachably attached to the attaching hole. 
     According to the above another invention, even if the wire is made detachable with respect to the angle ring, not only that the fixing at wire attachment is carried out surely but also there is an effect that the wire is not removed from the attaching and fixing portion or the wire is not elongated or cut off, either since the wire is not largely moved in the distal-end direction at the fixing portion. Therefore, the wire replacement is facilitated, and the repair cost can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a distal end portion and an angle portion illustrating an angle wire fixing structure of an endoscope according to a first embodiment of the present invention; 
         FIG. 2A  is a front view of a fixing member in the first embodiment; 
         FIG. 2B  is a sectional view illustrating a configuration of the distal end portion and the angle portion when a wire is attached in the first embodiment; 
         FIG. 3  is a diagram illustrating a variation of the fixing member and an attaching hole of the first embodiment; 
         FIG. 4  is an exploded perspective view of the angle portion illustrating the angle wire fixing structure of the endoscope in a second embodiment; 
         FIG. 5  is a sectional view illustrating a configuration of the distal end portion and the angle portion when the wire is attached in the second embodiment; 
         FIG. 6  is an exploded perspective view of the angle portion illustrating the angle wire fixing structure of the endoscope in a third embodiment; 
         FIG. 7A  is a sectional view when a perpendicular projection portion in the third embodiment is fitted in a groove of the fixing member; 
         FIG. 7B  is a sectional view illustrating a variation of the perpendicular projection portion and the groove of the fixing member in the third embodiment; 
         FIG. 8A  is an exploded perspective view of the angle portion illustrating the angle wire fixing structure of the endoscope of a fourth embodiment; 
         FIG. 8B  is a sectional view when the fixing member of the fourth embodiment is attached to the attaching hole; 
         FIG. 9A  is a front view of an angle ring in the angle wire fixing structure of the endoscope according to a fifth embodiment of the present invention; 
         FIG. 9B  is a side view of the angle ring and the wire in the fifth embodiment; 
         FIG. 9C  is a perspective view of the distal-end portion main body in the fifth embodiment; 
         FIG. 10  is a sectional view illustrating the configuration of the distal end portion and the angle portion when the wire is attached in the fifth embodiment; 
         FIG. 11  is a sectional view illustrating a variation of the fifth embodiment; 
         FIG. 12  are exploded perspective views of the angle portion illustrating the angle wire fixing structure of the endoscope of a sixth embodiment; 
         FIG. 13  is a sectional view illustrating the configuration of the distal end portion and the angle portion when the wire is attached in the sixth embodiment; and 
         FIG. 14  is a sectional view illustrating a configuration of the distal end portion and the angle portion of a conventional endoscope. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
       FIGS. 1 and 2  illustrate an angle wire fixing structure of an endoscope according to a first embodiment, and the endoscope comprises an insertion portion including a distal end portion and an angle portion (bending portion) and an operation portion and the like in general. In  FIG. 1 , a main body  10  of the distal end portion is configured to be coupled to an angle ring (the most distal end ring)  12  constituting the angle portion, and at this distal-end portion main body  10 , openings  10   a,    10   b  for an irradiation window and a light guide, an opening  10   c  for an observation window and an objective optical system, an opening  10   d  for a treatment instrument insertion channel and the like are provided. 
     In the first embodiment, as shown in  FIG. 1  or  2 A, a fixing member (stopper)  14  having a wire  13  fixed in a through hole at a lower part is provided, and the wire  13  is disposed to a winding-up wheel coupled to an angle operation knob of the operation portion. The fixing member  14  has its upper face formed in a columnar face in which grooves  16  for fixing with a width corresponding to a thickness of the angle ring  12  are formed on both side faces, and the fixing member  14  is provided at each of the four wires  13 . 
     On the other hand, on the side face of the angle ring  12  at the most distal end, a T-shaped attaching hole (attachment/detachment hole)  18  is provided at four spots at every 90 degrees on the outer circumferential circle, and the attaching hole  18  has such a size that a T-shaped horizontal portion (front side portion)  18   a  can accommodate insertion of the fixing member  14 , and a T-shaped perpendicular portion cut on the rear side thereof serves as a locking portion  18   b  by which the groove  16  for fixing is locked. 
     According to the first embodiment with the above configuration, in a state where the wire  13  is inserted into the angle ring  12 , the fixing member  14  is inserted into the T-shaped horizontal portion  18   a  of the attaching hole  18  as shown in  FIG. 1  and made to slide rearward while the locking portion  18   b  as the T-shaped perpendicular portion is fitted in the grooves  16  for fixing on the both sides (right side in the figure) so that the groove  16  for fixing is locked by the locking portion  18   b,  and the fixing member  14  is attached and fixed to the attaching hole  18 . After that, by inserting the distal-end portion main body  10  into the angle ring  12  through the distal-end opening thereof, the state shown in  FIG. 2B  is realized, and the wire  13  is attached and fixed to the angle ring  12 . In this case, since the fixing member  14  is not brazed or soldered to the attaching hole  18 , the wire  13  is made detachable with respect to the angle ring  12 , and replacement of only the wire  13  is made possible. 
     Moreover, in the first embodiment, since the groove  16  of the fixing member  14  is fitted in the locking portion  18   b  (wall body of the angle ring  12 ) of the attaching hole  18 , a firmly fixed state can be obtained. Also, as shown in  FIG. 2B , the distal-end portion main body  10  in the embodiment (length of the angle ring fitting portion) is set to a length brought into contact with the distal end face of the fixing member  14  having a rear end face  10 R thereof attached to the attaching hole  18 , thereby a possibility of removal of the fixing member  14  due to forward movement thereof is avoided. 
       FIG. 3  shows a variation of the first embodiment, and in this variation, as shown in  FIG. 3 , a groove  19   k  for fixing is formed on the rear side of a fixing member  19  to which the wire  13  is fixed, and an attaching hole  20 , which is a square hole with a size capable of accommodating insertion of the fixing member  19  and has a rear-side edge portion that serves as a locking portion  20   b,  is provided at the angle ring  12 . With this configuration, too, by fitting the locking portion  20   b  of the attaching hole  20  in the groove  19   k  for fixing and by locking the fixing member  19  by the locking portion  20   b,  a firmly fixed state can be obtained. 
     Second Embodiment 
       FIGS. 4 and 5  show an angle wire fixing structure of an endoscope of a second embodiment, and this second embodiment is configured to be screwed. As shown in the figure, the T-shaped attaching hole  18  having a T-shaped perpendicular portion as the locking portion  18   b  is provided in the angle ring  12  similarly to the first embodiment, a projection portion (a flange portion)  22 F is integrally formed on a fixing member  22  having the groove  16  formed so as to protrude to the front side above it, and a screw hole  24  through which a screw  23  is inserted is formed on the projection portion  22 F. 
     According to the configuration of the second embodiment, as shown in  FIG. 5 , in a state where the locking portion  18   b  is fitted in the groove  16  of the fixing member  14 , the fixing member  22  is attached to the attaching hole  18 , and the screw  23  can be screwed and fixed to the distal-end portion main body  10  through the screw hole  24  and the attaching hole  18  ( 18   a ). Therefore, in the second embodiment, not only that the fixing member  22  is fixed by the locking between the groove  16  thereof and the locking portion  18   b  but also the member is screwed, and the fixing member  22  and hence the wire  13  are firmly fixed. On the other hand, replacement of only the wire  13  is made possible by removing the screw  23 . 
     Third Embodiment 
       FIGS. 6 and 7  show an angle wire fixing structure of an endoscope of a third embodiment, and in the third embodiment, a perpendicular projection portion is provided at a locking and fixing portion of an attaching hole. As shown in  FIG. 6 , the attaching hole  18  similar to that in the first embodiment is provided at the angle ring  12  in the third embodiment, but in an edge of the locking portion (T-shaped perpendicular portion)  18   b  (longitudinal direction) of the attaching hole  18 , a perpendicular projection portion  26  having an edge portion thereof folded outward in the perpendicular direction is formed. On the other hand, in a fixing member  27 , as also shown in  FIG. 7A , a groove  28  for fixing with an L-shaped section is formed. 
     According to the configuration of the third embodiment, as shown in  FIG. 7A , by fitting the L-shaped locking portion  18   b  including the perpendicular projection portion  26  in the L-shaped groove  28  of the fixing member  27 , the wire  13  (distal-end fixing member  27 ) can be detachably attached to the angle ring  12  (attaching hole  18 ). Moreover, since the perpendicular projection portion  26  is provided in the L-shape, strength of the locking portion  18   b  itself is enhanced, and even in the frequent pulling operation of the wire  13 , the locking portion  18   b  would not be widened open. 
       FIG. 7B  shows a variation of the third embodiment, and as shown in the figure, in this variation, a perpendicular projection portion  29  having an edge portion thereof folded inward in the perpendicular direction is provided at the locking portion  18   b  of the attaching hole  18 , and a groove  30  for fixing in an inverted L-shape is formed in the fixing member  27 . With this configuration, too, the same effect as above can be obtained. 
     Fourth Embodiment 
       FIG. 8  shows an angle wire fixing structure of an endoscope of a fourth embodiment, and the fourth embodiment is configured so that an outer circumference of the fixing member complies with an outer circumferential circle of the angle ring. As shown in  FIG. 8 , in the fourth embodiment, a portion of the attaching hole  18  similar to that in the first embodiment (portion including the periphery) is recessed inward and formed into a flat face, and a sectional outer circumferential line (outer circumferential curved face)  31 S of a fixing member  31  is formed so as to become the same (radius) as a sectional outer circumferential circle (outer circumferential curved face) of the angle ring  12 . 
     According to the fourth embodiment, as shown in  FIG. 8B , the outer circumferential line  31 S of the fixing member  31  matches an outer circumferential circle C s  of the angle ring  12 , the fixing member  31  does not protrude from the outer circumference of the angle ring  12 , and thus, there is an advantage that the wire  13  is made detachable and a firm fixed state can be obtained without preventing narrowing of the diameter of the angle portion (insertion portion) and hence, the endoscope. 
     Fifth Embodiment 
       FIGS. 9 and 10  show an angle wire fixing structure of an endoscope according to a fifth embodiment, and the endoscope comprises an insertion portion including a distal end portion and an angle portion (bending portion) and an operation portion and the like in general. That is, a main body  50  at the distal end portion in  FIG. 9C  is configured to be coupled to an angle ring (most distal end ring)  52  in  FIG. 9B  constituting the angle portion, and the distal-end portion main body  50  has openings  50   a,    50   b  for an irradiation window and a light guide, an opening  50   c  for an observation window and an objective optical system, and an opening  50   d  for a treatment instrument insertion channel and the like. 
     In the fifth embodiment, as shown in  FIG. 9 , a cylindrical small body (stopper)  54  for locking is fixed to a distal end of a wire  53  by brazing, soldering and the like, and the wire  53  is disposed up to a winding-up wheel coupled to an angle operation knob of the operation portion. The small body  54  may be a small mass obtained by folding and brazing the wire distal end. On the other hand, on the inner circumference of the angle ring  52  at the most distal end, wire fixing portions  56  are provided at four spots at every 90 each (they are depicted in a larger way than they actually are), for example, and in the wire fixing portion  56 , a locking hole (through hole)  57  constituted by a small-diameter rear-side tube portion on which the wire  53  is arranged and a large-diameter front-side tube portion communicating with the tube portion and provided with a step for locking the small body  54  is formed. A length of the front-side tube portion (length in the axial direction) of the locking hole  57  is formed substantially the same as the length of the small body  54 . 
     A length L 1  [ FIG. 9C ] of a fitting portion  50 K into an angle ring on the rear side of the distal-end portion main body  50  is set substantially the same length as a length L 2  [ FIG. 9B ] from the distal end of the angle ring  52  to the wire fixing portion  56  (L 1 ≈L 2 ), by which movement (position) of the small body  54  can be regulated by the rear end of the distal-end portion main body  50 . 
     According to the fifth embodiment with the above configuration, as shown in  FIG. 10 , the wire  53  is inserted through the locking hole  57  of the wire fixing portion  56  in the angle ring  52  and arranged, the small body  54  at the distal end of the wire  53  is locked by the locking hole  57 , and then, the distal-end portion main body  50  is fitted through the distal-end opening of the angle ring  52  so as to attach the wire  53 . At this time, the rear end of the distal-end portion main body  50  (fitting portion  50 K) is brought into contact with the distal end portion of the small body  54  and holds the small body  54  so that the movement of the small body  54  in the distal-end direction is regulated. 
     As mentioned above in the fifth embodiment, since the small body  54  is not brazed or soldered to the locking hole  57  of the fixing portion  56 , by removing the distal-end portion main body  50  from the angle ring  52 , the wire  53  is made detachable with respect to the angle ring  52 , and replacement of only the wire  53  is made possible. Also, since the small body  54  is held by the rear end of the fitting portion  50 K (distal-end portion main body  50 ) having substantially the same length as the length from the distal end of the angle ring  52  to the wire fixing portion  56  (L 1 ≈L 2 ), removal of the wire  53  from the fixing portion  56  or elongation or cut-off in the wire  53  is not caused. 
       FIG. 11  shows a variation of the fifth embodiment, in which the length of the small body  54  is longer than the depth of the locking hole  57 . In this case, by setting a length L 3  from the distal end of the angle ring  52  to the distal end of the small body  54  substantially the same as a length L 1  of the fitting portion  50 K to the angle ring of the distal-end portion main body  50  (L 1 ≈L 3 ), the movement of the small body  54  in the distal-end direction can be regulated. 
     Sixth Embodiment 
       FIGS. 12 and 13  show an angle wire fixing structure of an endoscope of a sixth embodiment, and in the sixth embodiment, the wire fixing portion is made detachable. As shown in the figure, in the sixth embodiment, as shown in  FIG. 12 , similarly to the above embodiments, a fixing member  60  having the locking hole  57  formed in which a rear-side tube portion on which the wire  53  is arranged and a front-side tube portion provided with a step for locking the small body  54  is provided, and the small body  54  of the wire  53  is locked by the locking hole  57  of the fixing member  60 . The fixing member  60  has its upper face as a columnar face and has a groove  61  for fixing formed with a width corresponding to the thickness of the angle ring  52  on both side faces and arranged at each of the four wires  53 . 
     On the other hand, on the side face of the angle ring  52  at the most distal end, a T-shaped attaching hole (attachment/detachment hole)  63  is provided at four spots at every 90 degrees on the outer circumferential circle, and in the attaching hole  63 , a T-shaped horizontal portion (front side portion)  63   a  is of the size through which the fixing member  60  can be inserted, and a T-shaped perpendicular portion cut-in on the rear side serves as a locking portion  63   b  for locking the groove  61  for fixing. The configurations of the distal-end portion main body  50 , the lengths L 1 , L 2  of the angle ring  52  and the like are the same as those in the fifth embodiment. 
     According to the sixth embodiment with the above configuration, as shown in  FIG. 13 , in a state where the small body  54  of the wire  53  is locked by the locking hole  57  of the fixing member  60 , the fixing member  60  is inserted into the T-shaped horizontal portion  63   a  of the attaching hole  63 , and the locking portion  63   b  as the T-shaped perpendicular portion is made to slide rearward (right side in the figure) while being fitted in the groove  61  on the both sides so that the groove  61  for fixing is locked by the locking portion  63   b  and the fixing member  60  is attached and fixed to the attaching hole  63 . After that, by inserting the distal-end portion main body  50  into the angle ring  52  through the distal-end opening, the wire  53  is attached and fixed to the angle ring  52 . 
     In this case, too, by removing the distal-end portion main body  50  from the angle ring  52 , the wire  53  is made detachable with respect to the angle ring  52 , and replacement of only the wire  53  is made possible. Also, since the movement of the small body  54  is regulated by the rear end of the distal-end portion main body  50 , removal, elongation or cut-off of the wire  53  is not caused. Moreover, there is an advantage that, even in the case where the fixing member  60  is broken, repair is possible by replacing only the fixing member  60 . 
     
       
         
           
               
             
               
                   
               
               
                 Description of Symbols 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 2, 10, 50 
                 distal-end portion main body 
               
               
                   
                 3, 12, 52 
                 angle ring 
               
               
                   
                 5, 13, 53 
                 wire 
               
               
                   
                 14, 19, 22, 27, 31, 60 
                 fixing member 
               
               
                   
                 16, 28, 30, 61 
                 groove 
               
               
                   
                 18, 20, 63 
                 attaching hole 
               
               
                   
                 23 
                 screw 
               
               
                   
                 24 
                 screw hole 
               
               
                   
                 26, 29 
                 perpendicular projection portion 
               
               
                   
                 31S 
                 sectional outer circumferential line 
               
               
                   
                 50K, 56 
                 fitting portion 
               
               
                   
                 54 
                 small body 
               
               
                   
                 57 
                 locking hole