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 fig1 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 fig1 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 fig5 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 fig2 ) as the coil 7 is viewed along its cross section in the longitudinal direction . as shown in fig6 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 fig7 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 fig3 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 fig9 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 fig4 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 fig4 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 fig1 on the other hand , the operating section 3 is composed of an operating section body 19 and a slider 43 . as shown in fig1 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 fig1 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 fig1 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 fig1 ) 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 fig1 . 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 fig2 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 fig1 , 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 fig1 , 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 fig1 ) 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 fig2 , 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 .
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 .