Abstract:
An endoscopic instrument of the present invention comprises a flexible insert section capable of being passed through a forceps channel of an endoscope, an operating wire located in a bore of the insert section and movable in the axial direction of the insert section, an operating section connected to the proximal end side of the insert section and used to move the operating wire forward and backward, and a treatment section attached to the distal end of the insert section and adapted to be operated as the operating wire is moved forward and backward. The operating wire is composed of at least one wire member, a resin member is located on or adhered to at least a part of the outer surface of the operating wire, at least the inner surface of the insert section is formed of a metallic coil, and a micro-flat portion is provided at least on that surface portion of an element wire of the coil which faces the operating wire.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-145528, filed May 17, 2000, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an endoscopic instrument capable of being introduced into the human body through a forceps channel of an endoscope and used for medical treatment. 
     Conventionally, there is an endoscopic instrument  110  that comprises an elongated insert section  102  capable of being passed through a forceps channel  100  of an endoscope  101 , a treatment section  104  attached to the distal end of the insert section  102 , and an operating section  106  on the proximal end side of the insert section  102 , as shown in FIG. 23. A desired treatment is conducted as the distal treatment section  104  is operated by pushing or pulling an operating wire, which is movably passed through the insert section  102 , by means of the operating section  106 . In the insert section  102  of the endoscopic instrument  110 , as shown in FIG. 24, for example, a plastic tube  112  is located in a coil  108  that is formed of an element wire having a circular cross section, and a pair of operating wires  114 , 115  are passed through the tube  112  (cf. PCT National Publication No. 9-507420 (Symbiosis) or U.S. Pat. No. 5,133,727 (Symbiosis)). 
     In some endoscopic instruments such as biopsy forceps in which the distal treatment section  104  requires a force in carrying out treatment, a force of 10 kgf or more may be applied to the operating section  106  on the proximal end side. In this case, a similar force acts on the operating wires  114 , 115  that are passed through the coil  108  of the insert section  102 . In the endoscopic instrument (see FIG. 24) having the construction described in PCT National Publication No. 9-507420 or U.S. Pat. No. 5,133,727, therefore, the force that is directed toward the center of the curvature acts on the operating wires  114 ,  115  when the operating section  106  is operated with the endoscope  101  curved, as shown in FIG.  23 . As shown in FIGS. 24 and 25, moreover, the plastic tube  112 , which is designed to smoothen the slide of the wires  114 ,  115 , bites into the grooves  120  between the element wires of the coil  108 , so that the force of the operating section  106  cannot be efficiently transmitted to the distal treatment section. In this case, the wires  114 ,  115  and the tube  112  are not fixed. Since the sliding resistance between the coil  108  and the tube  112  is higher than the resistance between the tube  112  and the wires  114 , 115 , however, the wires  114 , 115  and the tube  112  move as one body in the coil  108  when the wires  114 , 115  are slid. If the movement of the plastic tube  112  is prevented, therefore, the force that is transmitted to the operating wires  114 , 115  attenuates. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an endoscopic instrument capable of efficiently transmitting an operating force to a treatment section without being influenced by the curved state of an endoscope. 
     The above object of the present invention is achieved by the following endoscopic instrument. The endoscopic instrument according to the invention comprises a flexible insert section capable of being passed through a forceps channel of an endoscope, an operating wire located in a bore of the insert section and movable in the axial direction of the insert section, an operating section connected to the proximal end side of the insert section and used to move the operating wire forward and backward, and a treatment section attached to the distal end of the insert section and adapted to be operated as the operating wire is moved forward and backward. The operating wire is composed of at least one wire member, a resin member is located on or adhered to at least a part of the outer surface of the operating wire, at least the inner surface of the insert section is formed of a metallic coil, and a micro-flat portion is provided at least on that surface portion of an element wire of the coil which faces the operating wire. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is a general view of an endoscopic biopsy forceps (endoscopic instrument) according to an embodiment of the present invention; 
     FIG. 2A is a side view, partially in section, showing biopsy cups of the endoscopic biopsy forceps of FIG. 1 in a closed state; 
     FIG. 2B is an axial front view of the biopsy cups of the biopsy forceps of FIG. 2A; 
     FIG. 3 is a side view, partially in section, showing the biopsy cups of the endoscopic biopsy forceps of FIG. 1 in an open state; 
     FIG. 4 is a sectional view taken along line  4 — 4  of FIG. 2A; 
     FIG. 5 is an enlarged sectional view showing an example of the profile of a coil; 
     FIG. 6 is an enlarged sectional view showing another example of the profile of a coil; 
     FIG. 7 is an enlarged sectional view showing still another example of the profile of a coil; 
     FIG. 8 is an enlarged sectional view showing a further example of the profile of a coil; 
     FIG. 9 is an enlarged sectional view showing a modification of an inner tube through which an operating wire is passed; 
     FIG. 10 is a detailed view of a portion indicated by arrow X in FIG. 1, the upper half of which is sectional; 
     FIG. 11 is a sectional view taken along line  11 — 11  of FIG. 10; 
     FIG. 12 is a sectional view taken along line  12 — 12  of FIG. 11; 
     FIG. 13 is a sectional view taken along line  13 — 13  of FIG. 11; 
     FIG. 14 is an enlarged view of a portion indicated by arrow XIV in FIG. 12; 
     FIG. 15 is a detailed view of a portion indicated by arrow XV in FIG. 1, the upper half of which is sectional; 
     FIG. 16 is a sectional view taken along line  16 — 16  of FIG. 15; 
     FIG. 17 is a sectional view taken along line  17 — 17  of FIG. 15; 
     FIG. 18 is a sectional view taken along line  18 — 18  of FIG. 15; 
     FIG. 19 is a sectional view taken along line  19 — 19  of FIG. 15; 
     FIG. 20 is a perspective view showing convex characters formed on the outer surface of a body lid of an operating section of the biopsy forceps of FIG. 1; 
     is FIG. 21 is a perspective view showing concave characters formed on the outer surface of the body lid of the operating section of the biopsy forceps of FIG. 
     FIG. 22 is a sectional view for illustrating the function of a configuration according to the one embodiment of the invention; 
     FIG. 23 is a view showing an endoscopic instrument in a general working state; 
     FIG. 24 is a sectional view showing a state of an insert section of the endoscopic instrument in a curved endoscope; and 
     FIG. 25 is an enlarged sectional view showing the state of the insert section of the endoscopic instrument in the curved endoscope. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention will now be described with reference to the accompanying drawings. Although a biopsy forceps will be described as an example of an endoscopic instrument according to this embodiment, it is to be understood that the invention may be applied to any other instruments such as a grasping forceps, thread cutting forceps, scissor-type forceps, hot-biopsy forceps, high-frequency snare, rotary clip device, ligature device, lithotripter, stone collecting basket, cytological brush, papillotome, etc. 
     As shown in FIG. 1, the endoscopic biopsy forceps  1  comprises a flexible insert section  2 , which can be passed through a forceps channel of an endoscope, and an operating section  3 . As shown in FIGS. 1 to  4 , the insert section  2  includes a coil  7  having a bore, an outer tube  10  formed covering the outer surface of the coil  7  by tubing or a heat-shrinkable tube, an inner tube  11  located in the bore of the coil  7 , two operating wires  8  and  9  each formed of a solid or stranded wire movable in a bore of the inner tube  11 . The insert section  2  further includes a cup holding member  6  fitted on and fixed to the distal end of the coil  7  by laser welding, brazing, soldering, or caulking, a pair of biopsy cups  4  and  5  for use as treatment sections rotatably mounted near the distal end of the cup holding member  6  by means of a pin  12 , and a needle  13 . The distal end side of the needle  13  is fixed between the biopsy cups  4  and  5  by means of the pin  12 , while the proximal side of the needle  13  is fitted in a hole  47  that is formed near the proximal side of the cup holding member  6 . 
     As shown in FIG. 5, an axially extending micro-flat portion  7 ′ is formed on the inner surface of the coil  7 , covering its overall length or at least a part thereof. In this case, the length of the micro-flat portion  7 ′ for the cross section of each element wire that extends in the longitudinal direction of the coil  7  is adjusted to 0.02 to 0.3 mm (see FIG. 22) as the coil  7  is viewed along its cross section in the longitudinal direction. As shown in FIG. 6, moreover, an axially extending micro-flat portion  7 ″ may be also formed on the outer surface of the coil  7 . In order to further improve the transmissibility of the operating wires  8  and  9  that are pulled to the proximal end side, a micro-flat portion  7 ″′ that is inclined at an angle θ′ to the axial direction may be formed on the inner surface of the coil  7  so that the bore of the coil  7  is tapered toward the proximal ens side, as shown in FIGS. 7 or  8 . Preferably, in this case, the angle θ′ should be adjusted to 45° or more. If the micro-flat portion  7 ″′ inclined at the angle θ′ is formed on the inner surface of the coil  7  in this manner, the operating wires  8  and  9  slide along the gradient with reduced resistance when they are pulled to the proximal end side. When the wires  8  and  9  are pushed to the distal end side, on the other hand, they move resisting the gradient. In this case, however, no force is generated to press the wires  8  and  9  against the coil  7 , so that the gradient never causes the resistance to increase. 
     Those portions of the operating wires  8  and  9  which are located in the coil  7  are passed substantially entirely through the inner tube  11 . As shown in FIG. 3, they are only passed through the bore of the inner tube  11  without being fixed to the tube  11 . Thus, the wires  8  and  9  can move back and forth in the tube  11 . Further, the outer surface of the inner tube  11  is embossed to reduce the area of contact between the tube  11  and the coil  7 , thereby improving the transmissibility and operating efficiency. It is to be desired, in this case, that the embossed roughness should preferably be adjusted to 200 μm or less, and further preferably to 13 to 20 μm, in terms of the width of irregularities. In order to smoothen the movement of the operating wires  8  and  9 , moreover, at least a part of the coil  7 , wires  8  and  9 , and/or inner tube  11  is coated with silicone oil as lubricant, and the surface roughness of the element wires of the coil is adjusted to 0.8 S (JIS). 
     As shown in FIG. 9, moreover, the inner tube  11  may be formed by coating the respective surfaces of the operating wires  8  and  9  with resin members  45  and  45 ′ by tubing, heat-shrinking, dipping, or spraying, in order to improve the assembly efficiency and lower the parts cost. It is to be understood, in this case, that the tube  11  may be embossed and coated with silicone oil in the same manner as previously. 
     In order to further improve the capability of the needle  13  to puncture tissue, the thickness of the needle  13  should preferably be adjusted to between 0.02 mm and 0.3 mm, and further preferably to 0.15 mm. The needle  13  may be fabricated by pressing, cold forging, or photo-etching. 
     As is clearly shown in FIG. 4, the respective distal end portions of the operating wires  8  and  9  are bent once substantially at right angles, and are inserted individually into holes  15  in the respective proximal end side portions of the biopsy cups  4  and  5 . In order to prevent the operating wires  8  and  9  from slipping out of the holes  15 , the respective distal ends of the wires  8  and  9 , bent substantially at right angles, are formed with a stopper portion  14 . The stopper portion  14  is crushed under pressure in the axial direction of the wires or perpendicular to their axes. As shown in FIG. 4, one end of the pin  12  is countersunk, and the other end is fixed to the cup holding member  6  by laser welding or caulking. 
     As shown in FIG. 1, on the other hand, the operating section  3  is composed of an operating section body  19  and a slider  43 . As shown in FIGS. 10 and 11, a cylindrical stopper  26  is fixed to the proximal side of the coil  7  by auto-slicing, caulking, brazing, soldering, or ultrasonic welding. The proximal side of the insert section  2  that includes the stopper  26  is located in the operating section body  19 , and can be fixed to the body  19  as a body lid  22  is depressed in the direction indicated by arrow T in FIG. 12 so that its click portions  28  are fitted individually in grooves  27  that are formed on the body  19 . With this arrangement, the operating section body  19  and the body lid  22  can be assembled with improved efficiency. 
     Further, the body lid  22  may be fixed to the operating section body  19  in a manner such that it is slid in the direction of arrow U in FIGS. 10 and 11 with the click portions  28  guided along the grooves  27 . In this case, the body lid  22  can be prevented from being easily disengaged from the body  19  if it is designed so that recesses  41  (see FIG. 13) therein individually engage retaining portions  40  on the body  19  after the retaining portions  40  are cleared by a taper portion  39  of the lid  22 . 
     In order to improve the strength of fixation between the operating section body  19  and the body lid  22 , the plane on which the grooves  27  and the click portions  28  engage one another is inclined at θ° (0°≦θ°&lt;90°) lest the lid  22  be easily disengaged from the body  19 , as shown in FIG.  14 . 
     Further, the body lid  22  may be colored so that it can be identified corresponding to the bore of the forceps channel of the endoscope. As shown in FIG. 20 or  21 , moreover, convex characters  200  or concave characters  300  that are indicative of a product name or the like may be put on the outer surface of the lid  22 . 
     As shown in FIGS. 15,  16  and  18 , the respective proximal end portions of the operating wires  8  and  9  are located in an operating pipe  25  that has a bore. Further, the proximal end portion of the pipe  25  is fitted in a side hole  44  of a stopper  30 , and is screwed to the stopper  30  as the pipe  25  including the wires  8  and  9  is deformed by means of a screw  31 . Thus, the fixing strength of the wires  8  and  9  is improved. The proximal end portions of the operating wires  8  and  9  including the operating pipe  25 , stopper  30 , and screw  31  are arranged in a manner such that the stopper  30  engages recesses  34  in slider members  20  and  20 ′ that constitute the slider  43 . As shown in FIGS. 15,  17  and  19 , moreover, the slider members  20  and  20 ′ are bonded to each other by ultrasonic welding or the like in a manner such that projections  36  of the slider member  20 ′ is individually in engagement with recesses  35  of the slider member  20 . In the ultrasonic welding operation, two pairs of symmetrical projections  32  on the slider members  20  and  20 ′ are melted so that the members  20  and  20 ′ are welded to each other. In this case, recesses  33  are escapes that prevent formation of gaps in junctions when the projections  32  are melted. Further, the slider members  20  and  20 ′ are composed of two symmetrical components of the same shape, so that they can be assembled without directivity, and the parts cost can be lowered. An escape  37  is a depression for preventing external projection that is attributable to pin-gate processing. 
     A stopper  21  (see FIG. 1) functions as a regulating member for the slide of the slider  43  between slits  24  that are formed extending in the longitudinal direction of the operating section body  19 . With use of the stopper  21 , the operating pipe  25  can be prevented from being disengaged from the coil  7  when the slider  43  is slid at a fixed stroke, and the distance between the slider  43  and a thumb ring  23  on the proximal end of the body  19  can be adjusted to facilitate the operation. 
     In the present embodiment, the outer tube  10 , inner tube  11 , and resin members  45  and  45 ′ are formed of the following plastic materials and their combinations. The plastic materials include, for example, polyolefin plastic materials such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), etc., fluoroplastic materials such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro-alkoxy-ethylene resin (PFA), tetrafluoroethylene-hexafluoropropylene resin (FEP), tetrafluoroethylene-ethylene (ETFE), etc., plastic materials such as polyamide (PA), polyacetal (POM), polyether-ether-ketone (PEEK), polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS), etc. 
     Further, the biopsy cups  4  and  5  and the cup holding member  6  are formed of the following metal or plastic materials. The metal materials include, for example, stainless steel, aluminum, nickel, brass, titanium, iron, phosphor bronze, tungsten, gold, silver, copper, SF 20 T (ferrite-based stainless steel, chemical components: C≦0.05 wt %, Si≦1 wt %, Mn≦2 wt %, P≦0.05 wt %, S≧0.15 wt %, Cr=19 to 21 wt %, Mo=1.5 to 2.5 wt %, Pb=0.1 to 0.3 wt %, and Te=0.01 to 0.07 wt %), etc. or alloys of these metals. The plastic materials include, for example, polyolefin plastic materials, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), etc., fluoroplastic materials, such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoro-alkoxy-ethylene resin (PFA), tetrafluoroethylene-hexafluoropropylene resin (FEP), tetrafluoroethylene-ethylene (ETFE), etc., polyamide (PA), polyacetal (POM), polyether-ether-ketone (PEEK), polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS), liquid crystal polymers, etc. 
     Furthermore, the coil  7 , operating wires  8  and  9 , and needle  13  are formed of metal materials, such as stainless steel, aluminum, nickel, brass, titanium, iron, phosphor bronze, tungsten, gold, silver, copper, etc. or alloys of these metals or high-tensile-strength materials (materials having high resistance to tension) based on these metals. 
     In the arrangement of the present embodiment described above, the operating wires  8  and  9  are slid in the bore of the coil  7  by means of the slider  43  that can slide on the operating section body  19 . As this is done, the biopsy cups  4  and  5  that are connected to the respective distal ends of the operating wires  8  and  9  are opened or closed, whereupon tissue in an organism is biopsied by means of the cups  4  and  5 . In this case, the micro-flat portion  7 ′, 0.2 to 0.3 mm wide, is formed on the inner surface of the coil  7 . If the coil  7  is curved in the manner shown in FIG. 22, therefore, the plastic tube  11  on the respective outer surfaces of the operating wires  8  and  9  can never get into the spaces between the element wires of the coil  7  and hinder the movement of the wires  8  and  9 . Thus, the force that is applied to the operating section  3  can be efficiently transmitted to the treatment sections  4  and  5  by means of the wires  8  and  9 , respectively, so that a strong force can be generated during treatment. 
     According to the endoscopic biopsy forceps  1  of the present embodiment, as described above, the force that is applied to the operating section  3  can be efficiently transmitted to the biopsy cups  4  and  5  without being influenced by the curved state of the endoscope, so that tissue can be easily biopsied with a light force. Thus, a doctor or care assistant can be eased of his/her burden during treatment operation. Since the inside diameter of the coil  7  can be made greater than that of a conventional coil, moreover, a generous clearance can be secured between the operating wires  8  and  9 , so that the operating efficiency of the wires  8  and  9  can be raised. Furthermore since the forceps  1  requires no substantial change in construction, its function can be improved without entailing any increase in cost. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.