Patent Publication Number: US-2019191965-A1

Title: Endoscope

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT/JP2017/015437 filed on Apr. 17, 2017 and claims benefit of Japanese Application No. 2016-173836 filed in Japan on Sep. 6, 2016, the entire contents of which are incorporated herein by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope provided with a pulling wire to cause a bending portion to bend. 
     2. Description of the Related Art 
     An endoscope has an elongated insertion portion and is provided with an observation optical system and the like for picking up an observation image of an observed region on a distal end side of the insertion portion. Among endoscopes, some endoscopes are provided with a bending portion on a distal end portion side of the insertion portion. In an endoscope provided with the bending portion on the insertion portion, insertion into a depth can be easily performed, and it becomes possible to direct the observation optical system located on the distal end side in a desired direction. 
     The bending portion is configured mainly with a bending tube and bending rubber covering the bending tube. The bending tube is, for example, a bending piece set configured with a plurality of bending pieces that are turnably and continuously provided or a rigid pipe for bending portion that is bendably configured by providing a plurality of slots on a rigid pipe. The bending tube is configured to bend in two directions of upward and downward directions or four directions of upward, downward, left and right directions. 
     In the bending tube, a plurality of pulling wires corresponding to the bending directions are inserted. Distal ends of the pulling wires are fixed to a distal end nodal ring or the like constituting a most distal end of the bending tube. Proximal ends of the pulling wires are fixed to a bending operation apparatus arranged in an operation portion provided on a proximal end side of the insertion portion. According to the configuration, the bending portion bends by a user operating the bending operation apparatus to pull or loosen the pulling wires. 
     FIG. 7 of Japanese Patent Application Laid-Open Publication No. 2001-149307 discloses that distal ends of pulling wires are fixed to a connection member.  FIG. 9  discloses a technique for directly laser-welding the connection member to an inner circumferential face of a nodal ring to join the connection member. 
       FIG. 18( a )  of Japanese Patent Application Laid-Open Publication No. 2002-236260 shows a wire fixing portion provided by cutting and bending a side wall of a distal end piece. Distal ends of pulling wires are fixed to the wire fixing portion by solder or the like.  FIG. 18( b )  of Japanese Patent Application Laid-Open Publication No. 2002-236260 shows a notch portion for confirming the wire fixing portion. 
     SUMMARY OF THE INVENTION 
     An endoscope of an aspect of the present invention is provided with: a wire including a first end portion and a second end portion, the wire being inserted in an endoscope insertion portion; a tubular member, the first end portion side of the wire being arranged along an inner circumferential face of the tubular member, the first end portion side of the wire being joined at a predetermined position on a distal end of the tubular member by welding, the wire being arranged immediately below a first through hole including openings at predetermined positions on the inner circumferential face and an outer circumferential face of the tubular member; a distal end member including a small diameter portion arranged to be fitted in a distal end side inner circumferential face of the tubular member and a large diameter portion provided on a distal end side of the small diameter portion, the large diameter portion having a diameter larger than a diameter of the small diameter portion; an accommodating portion formed on an outer circumferential face side of the small diameter portion, the first end portion of the wire being accommodated in the accommodating portion; and a relief portion formed by the accommodating portion extending to the large diameter portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an endoscope having a bending portion as a part of an insertion portion; 
         FIG. 2  is a diagram illustrating a configuration of a distal end face, and a relationship between a distal end rigid member and a distal end nodal ring; 
         FIG. 3  is a longitudinal cross-sectional view illustrating a configuration of a distal end side of the insertion portion; 
         FIG. 4A  is a plan view of the distal end rigid member seen from upward; 
         FIG. 4B  is a cross-sectional view along a line shown by arrows Y 4 B in  FIG. 4A ; 
         FIG. 4C  is a rear view of the distal end rigid member seen from a proximal end face side; 
         FIG. 5  is a cross-sectional view illustrating the distal end nodal ring; 
         FIG. 6A  is a diagram illustrating joining of a pulling wire to the distal end nodal ring and is a diagram illustrating the pulling wire and the distal end nodal ring and the distal end rigid member; 
         FIG. 6B  is a diagram in which the distal end nodal ring is fitted to a small diameter portion and is a diagram illustrating a state in which an inner circumferential face of the distal end nodal ring is in contact with the pulling wire in an accommodating groove  30 ; 
         FIG. 6C  is a diagram in which the pulling wire is arranged along the inner circumferential face of the distal end nodal ring and is a diagram showing a state in which the pulling wire is located immediately below a first through hole; 
         FIG. 6D  is a diagram of the distal end rigid member and the distal end nodal ring seen from a direction shown by an arrow Y 6 D in  FIG. 6C ; 
         FIG. 6E  is a diagram illustrating welding by laser light and is a diagram illustrating a state in which laser light is radiated to a first through hole side surface of the distal end nodal ring; 
         FIG. 6F  is a diagram showing a state in which one end side end portion of the pulling wire is joined to the distal end nodal ring by a joining portion obtained by radiating the laser light; and 
         FIG. 7  is a diagram illustrating the distal end nodal ring provided with first through holes and second through holes. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     An embodiment of the present invention will be described below with reference to drawings. 
     Note that, on each drawing used in the description below, a reduced scale may be different for each component so that the component is in a size recognizable on the drawing. That is, the present invention is not limited only to the number of components, shapes of the components, a size ratio among the components, and a relative positional relationship among the respective components illustrated on the drawings. 
     An endoscope  1  shown in  FIG. 1  is mainly provided with an endoscope insertion portion (hereinafter abbreviated as an insertion portion)  2 , an endoscope operation portion (hereinafter abbreviated as an operation portion)  3  and a universal cord  4 . The insertion portion  2  has a small diameter and is configured with a distal end portion  5 , a bending portion  6  and a flexible tube portion  7  continuously provided in that order from a distal end side. 
     On a distal end face  5   a  of the distal end portion  5 , for example, an observation window  5   b , two illumination windows  5   c , a treatment instrument opening  5   d  and the like are provided as shown in  FIGS. 2 and 3 . 
     The bending portion  6  is provided in the middle of the insertion portion  2  and is configured to bend, for example, in upward and downward directions. As shown in  FIG. 3 , the bending portion  6  is configured, mainly including bending rubber  11  and a bending tube  12 . Pulling wires  13  are inserted in the bending tube  12 . 
     The flexible tube portion  7  is a tube body having flexibility and is configured to passively bend. 
     As shown in  FIG. 1 , the operation portion  3  is provided on a proximal end side of the flexible tube portion  7 . The operation portion  3  is provided with a bending operation apparatus  8 , a treatment instrument insertion slot  9 , a plurality of remote switches  10 , a suction slot (not shown) and the like. The plurality of remote switches  10  are switches for stopping an endoscopic image displayed on a screen of a display apparatus (not shown) or performing recording, enlargement of an image, switching of illumination light and the like. 
     The bending operation apparatus  8  is, for example, an L-shaped lever and is turnably shaft-fixed relative to the operation portion  3 . The bending operation apparatus  8  is operated when the user causes the bending portion  6  to bend. The pulling wires  13  are pulled or loosened, accompanying an operation of the bending operation apparatus  8 , and the bending portion  6  bends in the upward or downward direction. 
     Note that the bending portion  6  described above is configured to bend in the upward and downward directions. The bending portion  6  may be, however, configured to bend in four directions of upward, downward, left and right directions. In that case, the operation portion  3  is provided with a lever for the left and right directions in addition to the lever for the upward and downward directions. By a turning operation of the operation lever for the left and right directions being performed, a pulling wire for the left or right direction is pulled or loosened, and the bending portion  6  bends in the left direction or the right direction. The bending operation apparatus  8  is not limited to the L-shaped lever but may be a circular-shaped turning knob, a joystick-type stick-shaped lever which is tilt-operated, or the like. 
     The universal cord  4  extends from a side portion of the operation portion  3 . A proximal end portion of the universal cord  4  is provided with an endoscope connector (not shown). The endoscope connector is connected to a light source apparatus which is an external apparatus. 
     As shown in  FIGS. 2 to 4C , the distal end portion  5  is provided with a distal end rigid member  20  which is a frame member. The distal end rigid member  20  is a rigid member made of metal or resin. The distal end rigid member  20  is provided with an image pickup apparatus hole  24 , a treatment instrument/suction hole  25 , a first illumination hole  26 , a second illumination hole  27  and the like which are through holes in an axial direction. Note that it becomes easy to use a high-frequency treatment instrument by causing the distal end rigid member  20  to be made of resin. 
     As shown in  FIG. 3 , an image pickup apparatus  28  is arranged in the image pickup apparatus hole  24 . Reference numeral  28   a  indicates a signal cable, which extends from the image pickup apparatus  28 . A connection pipe  29  is arranged in the treatment instrument/suction hole  25 . Reference numeral  29   a  indicates a treatment instrument channel tube, and a tube distal end side of the treatment instrument channel tube  29   a  is fixed to a pipe proximal end side of the connection pipe  29 . Illumination fibers (not shown) with distal end faces arranged facing the illumination windows  5   c  are arranged in the first illumination hole  26  and the second illumination hole  27 , respectively. 
     The bending portion  6  is configured mainly including the bending rubber  11  and the bending tube  12 . In the present embodiment, the bending tube  12  is a bending piece set configured with a plurality of bending pieces that are turnably coupled. Therefore, the bending tube  12 , which is a bending piece set, is configured by turnably coupling a distal end tubular member (hereinafter referred to as a distal end nodal ring)  14 , a plurality of intermediate tubular members (hereinafter referred to as intermediate nodal rings)  15  and a proximal end tubular member (not shown), which are tubular members, from a distal end side in that order. The distal end nodal ring  14  is fixed to a proximal end side of the distal end rigid member  20 . 
     In the bending tube  12 , the pulling wires  13  are inserted along a longitudinal axis a 2  of the insertion portion  2 . Each pulling wire  13  is provided with one end and the other end, and the one end side is joined to a predetermined position on the distal end nodal ring  14  by welding. Reference numeral  16  indicates a joining portion. 
     The other end of the pulling wire  13  passes through the insertion portion  2  and is extended into the operation portion  3 . The other end is fixed to a pulley (not shown) constituting the bending operation apparatus  8  arranged in the operation portion  3 . 
     Note that reference numeral  17  indicates wire guides provided on the intermediate nodal rings  15 , and each pulling wire  13  is inserted through the wire guides  17 . The bending tube  12  is not limited to a bending piece set but may be a rigid pipe for bending portion that is bendably configured by providing a plurality of slots on a rigid pipe as described before. The longitudinal axis a 2  includes the longitudinal axis of the insertion portion  2 , a central axis of the distal end rigid member  20  and a central axis of each nodal ring. 
     The distal end rigid member  20  and the distal end nodal ring  14  will be described with reference to  FIGS. 4A to 5 . 
     The distal end rigid member  20  shown in  FIGS. 4A, 4B and 4C  is in a stepped shape and is provided with, for example, a large diameter portion  21 , an intermediate portion  22  and a small diameter portion  23  from the distal end face  5   a  side in that order. The large diameter portion  21  is an exterior portion and constitutes a distal end outer surface exposed outside the distal end portion  5 . 
     The intermediate portion  22  is a bending rubber covered portion, which is covered with a distal end portion of the bending rubber  11 . A bobbin adhesive portion  18  is provided on a distal end side outer circumferential face of the bending rubber  11 . The bobbin adhesive portion  18  firmly and closely fixes the distal end portion of the bending rubber  11  to an outer circumferential face of the intermediate portion  22 . 
     The small diameter portion  23  is a distal end nodal ring fixing portion and is arranged being fitted to a distal end side of the distal end nodal ring  14 . In an arranged state, an inner circumferential face  14   i  of the distal end nodal ring  14  and an outer circumferential surface  23   f , which is an outer circumferential face of the small diameter portion  23 , are integrally fixed by adhesion, joining or the like. 
     In the present embodiment, the large diameter portion  21  has a diameter larger than a diameter of the intermediate portion  22  by a predetermined dimension, and the intermediate portion  22  has a diameter larger than a diameter of the small diameter portion  23  by a predetermined dimension. 
     As shown in  FIGS. 4B and 4C , on a proximal end face side of the distal end rigid member  20  of the present embodiment, two accommodating grooves  30 , which are groove portions, are provided in an opposing positional relationship. The accommodating grooves  30  of the present embodiment correspond to upward and downward directions of the bending portion  6  and are provided at predetermined positions. 
     One end side portions of the pulling wires  13  are accommodated in the accommodating grooves  30 , respectively. As shown in  FIG. 4A , each accommodating groove  30  is a stop groove set to a predetermined length and extending along the central axis of the distal end rigid member  20  from the proximal end face of the distal end rigid member  20 . In the present embodiment, a terminal end portion of each accommodating groove  30  is located in the middle of the intermediate portion  22 . Therefore, each accommodating groove  30  of the present embodiment is provided with a wire accommodating portion  31  provided on the small diameter portion  23  and a relief portion  32  provided on the intermediate portion  22 . 
     A width of the wire accommodating portion  31  is set larger than a dimension of an outer diameter of the pulling wires  13  by a predetermined dimension. In comparison, a depth of the wire accommodating portion  31 , that is, a distance from the outer circumferential surface  23   f  of the small diameter portion  23  to a groove bottom face is set to a same dimension as the outer diameter of the pulling wires  13  or smaller than the outer diameter by a predetermined dimension. On the other hand, a width of the relief portion  32  is a same dimension as the width of the wire accommodating portion  31  or larger than the width of the wire accommodating portion  31 . A depth of the relief portion  32  is set to a same dimension as the depth of the wire accommodating portion  31  or set larger than the depth of the wire accommodating portion  31 . Note that the depth and width of the wire accommodating portion  31  are set according to the outer diameter of the pulling wires  13 . 
     A configuration of the distal end nodal ring  14  will be described with reference to  FIG. 5 . 
     The distal end side of the distal end nodal ring  14  is arranged being fitted to the small diameter portion  23 . That is, the inner circumferential face  14   i  of the distal end nodal ring  14  is arranged on the outer circumferential surface  23   f  of the small diameter portion  23 . 
     At predetermined positions of the distal end nodal ring  14  of the present embodiment, first through holes  14   h , each of which has openings on the inner circumferential face  14   i  and an outer circumferential face  14   o , respectively, are formed. Each first through hole  14   h  is used as both of a window for visually confirming whether a pulling wire  13  is arranged or not and an indicator to specify a range within which laser light is to be radiated at the time of welding the pulling wire  13  to the distal end nodal ring  14 . Note that a diameter of the first through holes  14   h  is appropriately set in consideration of the diameter of the pulling wires  13 . Note that, in  FIG. 5 , central axes of the first through holes  14   h  are assumed to be axes orthogonal to a central axis a 14  of the distal end nodal ring  14 . 
     In the present embodiment, the first through holes  14   h  are provided in an opposing positional relationship similarly to the accommodating grooves  30  of the distal end rigid member  20  and provided corresponding to the upward direction and downward direction of the bending portion  6 . A state in which the accommodating grooves  30  and the first through holes  14   h  are arranged on straight lines, respectively, along the longitudinal axis a 2  of the insertion portion  2  in a state of the distal end nodal ring  14  being arranged in the small diameter portion  23  of the distal end rigid member  20  is an appropriate attachment state. 
     Here, joining of a pulling wire  13  to the distal end nodal ring  14  by welding will be described with reference to  FIGS. 6A to 6F . 
     At the time of joining the pulling wire  13  to the distal end nodal ring  14 , an operator prepares the distal end rigid member  20  in addition to the pulling wire  13  and the distal end nodal ring  14  shown in  FIG. 6A . 
     First, as shown by an arrow Y 6 A in  FIG. 6A , the operator moves one end side of the pulling wire  13  toward a corresponding accommodating groove  30  of the distal end rigid member  20 . Then, while a most distal end portion on the one end side of the pulling wire  13  is accommodated in the relief portion  32 , a proximal end side of the most distal end portion of the pulling wire  13  is accommodated in the wire accommodating portion  31 . 
     Next, as shown in  FIG. 6B , the operator arranges the distal end nodal ring  14  on the small diameter portion  23  of the distal end rigid member  20  in the state of the pulling wire  13  being accommodated in the accommodating groove  30 . At this time, a distal end face of the distal end nodal ring  14  is caused to face a proximal end face of the small diameter portion  23  of the distal end rigid member  20  so that the first through hole  14   h  and the accommodating groove  30  shown in  FIG. 6A  are arranged on one straight line. 
     Then, as shown in  FIG. 6B , the operator fits the distal end nodal ring  14  to the small diameter portion  23 . Then, the inner circumferential face  14   i  of the distal end nodal ring  14  comes into contact with the pulling wire  13  accommodated in the accommodating groove  30 , and the pulling wire  13  is in a stably held state by being sandwiched between an inner face of the wire accommodating portion  31  of the distal end rigid member  20  and the inner circumferential face  14   i  of the distal end nodal ring  14 . Thus, by setting the depth and width of the wire accommodating portion  31  according to the outer diameter of the pulling wires  13 , a stably held state can be certainly obtained. 
     Next, as shown in  FIG. 6C , the operator causes the pulling wire  13  to be arranged along the inner circumferential face  14   i  of the distal end nodal ring  14 . At this time, the operator performs adjustment so that the pulling wire  13  passes immediately below the first through hole  14   h.    
     Then, the operator performs positional adjustment to obtain an appropriate arrangement position and arranges the pulling wire  13  so that the pulling wire  13  can be visually confirmed through the first through hole  14   h  as shown in  FIG. 6D . 
     In the appropriate arrangement state, the operator performs laser welding work. That is, as shown in  FIG. 6E , the operator radiates laser light onto a surface of the distal end nodal ring  14  on the first through hole  14   h  side to start welding, and increases a welding range toward the accommodating groove  30  as indicated by an arrow Y 6 E. 
     As a result, as shown in  FIG. 6F , the distal end nodal ring  14  on which the laser light has been radiated and one end side end portion of the pulling wire  13  can be joined and fixed by a joining portion  16 . That is, as shown in  FIG. 3 , the bending portion  6  in which the one end side of each pulling wire  13  is fixed to the inner circumferential face  14   i  of the distal end nodal ring  14  is obtained. 
     As described above, the distal end rigid member  20  is provided with the accommodating grooves  30  capable of accommodating end portions of the pulling wires  13 , respectively; the one end side end portions of the pulling wires  13  are accommodated in the accommodating grooves  30 ; and, after that, the distal end nodal ring  14  is fitted to the small diameter portion  23  provided with the accommodating grooves  30 . Consequently, one end portion of each pulling wire  13  can be sandwiched and held between the small diameter portion  23  and the distal end nodal ring  14 . 
     In the held state, the accommodating grooves  30  of the distal end rigid member  20  and the first through holes  14   h  of the distal end nodal ring  14  are arranged on straight lines, respectively, along the longitudinal axis a 2 . Consequently, at the time of causing each pulling wire  13  to extend to the nodal ring proximal end side along the inner circumferential face  14   i , it is possible to visually confirm the pulling wire  13  by causing the pulling wire  13  to pass immediately below a corresponding first through hole  14   h  and grasp that the one end portion side of the pulling wire  13  is accommodated at a predetermined position. 
     After that, the operator can grasp a position of the pulling wire  13  arranged on the inner circumferential face  14   i  side of the distal end nodal ring  14  from positions of a corresponding accommodating groove  30  and first through hole  14   h  to perform welding work. That is, the operator can grasp the arrangement position of the pulling wire  13  and efficiently and certainly perform welding work for welding the pulling wire  13  to the distal end nodal ring  14  with a high accuracy. 
     Moreover, since a jig for connecting the pulling wire  13  to the distal end nodal ring  14  becomes unnecessary, manufacturing costs can be further reduced. 
     Since the one end side of each pulling wire  13  can be directly joined to the inner circumferential face  14   i  of the distal end nodal ring  14  by welding, a connection member or a wire fixing portion that can cause an internal space on a central axis side of the insertion portion  2  in which the pulling wire  13  is inserted to be narrow become unnecessary, so that the diameter of the insertion portion  2  can be reduced. 
     By each accommodating groove  30  being configured with the wire accommodating portion  31  provided in the small diameter portion  23  and the relief portion  32  provided in the intermediate portion  22 , it is possible to conveniently accommodate the one end side end portions of the pulling wires  13  into the accommodating grooves  30  without performing end portion processing of the pulling wire  13 . 
     Note that each accommodating groove  30  may be configured only with the wire accommodating portion  31  provided in the small diameter portion  23 . In this case, after newly performing end portion processing work for processing the end portion of each pulling wire  13 , the processed one end side end portion of the pulling wire  13  is accommodated into the wire accommodating portion  31 . 
     In the embodiment described above, the first through holes  14   h  are formed in the distal end nodal ring  14 . However, as shown in  FIG. 7 , second through holes  14   k  may be formed in the distal end nodal ring  14  on a distal end side or proximal end side of the first through holes  14   h , respectively, in addition to the first through holes  14   h . Then, the distal end nodal ring  14  including the first through holes  14   h  and the second through holes  14   k  is provided on the distal end rigid member  20 . 
     Note that each second through hole  14   k  is used as both of a window for visually confirming whether a pulling wire  13  is arranged or not and an indicator to specify a range within which laser light is to be radiated at the time of welding the pulling wire  13  to the distal end nodal ring  14  similarly to each first through hole  14   h . The first through holes  14   h  and the second through holes  14   k  provided on the distal end nodal ring  14  are provided being separated by a predetermined distance L along a nodal ring center, respectively. The distance L is a length required for welding fixation. 
     According to the configuration, by arranging the pulling wires  13  immediately below the first through holes  14   h  and the second through holes  14   k , respectively, it is possible to more certainly grasp a position of the pulling wire  13  arranged on the inner circumferential face  14   i  side of the distal end nodal ring  14  and more easily and certainly grasp a welding range to perform welding work. 
     As a result, it is possible to firmly join and fix the one end side end portion of the pulling wire  13  to the distal end nodal ring  14  without measuring length dimensions of the joining portion  16 . 
     Note that when the bending portion  6  is configured using the distal end nodal ring  14  shown in  FIG. 7 , the accommodating grooves  30  of the distal end rigid member  20  may be unnecessary. In this case, after arranging the end portion of each pulling wire  13  in a corresponding second through hole  14   k , the pulling wire  13  is temporarily fixed to the distal end nodal ring  14  by welding. After that, the pulling wire  13  is caused to pass immediately below a corresponding first through hole  14   h . While the state is being kept, welding between the first through hole  14   h  and the second through hole  14   k  is performed to provide the joining portion  16  described above, and the pulling wire  13  is fixed to the distal end nodal ring  14 . 
     After that, the distal end nodal ring  14  to which the pulling wires  13  are joined is arranged on the small diameter portion  23  of the distal end rigid member  20  and fixed. Consequently, it is possible to provide the endoscope  1  provided with the bending portion  6  having operation and effects similar to the operation and effects of the embodiment described above. 
     According to the present invention, it is possible to, while reducing a diameter of an endoscope insertion portion, provide such an endoscope that pulling wires are efficiently welded with a high accuracy at predetermined positions of a tubular member constituting a bending portion, and cost reduction is realized. 
     The present invention is not limited to only the embodiment described above, but various modifications can be implemented within a range not departing from the spirit of the invention.