hereinafter , preferred embodiments of an endoscope according to the invention will be described in detail with reference to the accompanying drawings . fig1 is an entire configuration diagram of an endoscope according to a first embodiment of the invention , and fig2 is a partially cutaway perspective view of an operating portion shown in fig1 . in addition , description will be made with the same reference numerals being given to the same members as the members shown in fig1 . an endoscope 100 includes an operating portion 41 , and an insertion portion 43 connected to the operating portion 41 and inserted into an abdominal cavity . a universal cable 45 is connected to the operating portion 41 , and a light guide connector ( not shown ) is provided at the tip of the universal cable 45 . the light guide connector is detachably connected to a light source , and illumination light is sent to an illumination optical system at a tip 43 a of the insertion portion . additionally , an electrical connector is connected to the light guide connector , and this electrical connector is detachably connected to a processor . an air supply / water supply button 47 , a suction button 49 , a shutter button 51 , and a function switching button 53 are provided in parallel in the operating portion 41 , and angle knobs 55 a and 55 b that are a pair of operating means are provided in the operating portion . the operating portion 41 is formed with a connecting portion 59 connected to the insertion portion 43 , and the connecting portion 59 has a forceps insertion portion 61 . by inserting a treatment instrument , such as forceps , into forceps insertion portion 61 , this treatment instrument is led out from a forceps port ( not shown ) of the tip 43 a of the insertion portion . a pulley 13 is provided inside the operating portion 41 , and the pulley 13 is fixed to one , for example , angle knob 55 a coaxially with a rotary shaft 15 . a pair of operating wires 17 a and 17 b that are bending operating wires is wound around the pulley 13 , and the operating wires 17 a and 17 b are connected to angular pipe - shaped sleeves 21 a and 21 b that are wire - connecting members 21 arranged on the side of the insertion portion 43 . fig3 is an enlarged plan view of the inside of the operating portion shown in fig2 . slip - off preventing members 23 are respectively housed inside the sleeves 21 a and 21 b so as to be movable in an axial direction , and the slip - off preventing members are respectively connected to ends of the operating wires 17 a and 17 b . that is , the operating wires 17 a and 17 b are connected to the sleeves 21 a and 21 b with the play equivalent to the movement of the slip - off preventing members 23 . ends of driving wires 25 a and 25 b that are bending operating wires are respectively fixed to the other ends of the sleeves 21 a and 21 b . here , the wire connection structure by the sleeves 21 a and 21 b will be described in more detail . fig4 is a sectional view of a sleeve . since the connection structures of the sleeves 21 a and 21 b are the same , one sleeve 21 a will be described here as an example . the sleeve 21 a is angular pipe - shaped , and has inside dimensions such that the sleeve may house the slip - off preventing member 23 . an opening at one end of the sleeve 21 a is made narrower than the slip - off preventing member 23 , and the operating wire 17 a may be inserted through the opening , but the slip - off preventing members 23 does not slip off . the operating wire 17 a is connected to the sleeve 21 a by such a slip - off preventing mechanism without being separated from the sleeve . the operating wire 17 a becomes movable in the axial direction within the sleeve 21 a . a threaded portion 63 is formed in an inner wall of the sleeve 21 a opposite the aforementioned slip - off preventing mechanism . the tip of the driving wire 25 a is anchored to an engaging tube 65 by soldering or the like . the engaging tube 65 is inserted into a screw member 67 , and the screw member 67 is screwed to the threaded portion 63 of the sleeve 21 a . the end of the engaging tube 65 opposite the sleeve 21 a protrudes from the screw member 67 , and a threaded groove is formed at an outer periphery of the protruding portion . the engaging tube 65 is fixed to the screw member 67 as a nut 69 is screwed to the threaded groove . on the other hand , the end of the engaging tube 65 on the side of the sleeve 21 a is prevented from slipping out by making its enlarged diameter portion abut on a stepped portion of the screw member 67 . by adopting the above configuration as the connection structure of the operating wire 17 a and the driving wire 25 a , the driving wire 25 a is fixed to the sleeve 21 a , the operating wire 17 a becomes movable with respect to the sleeve 21 a . as a result , the driving wire 25 a and the operating wire 17 a are connected with the play equivalent to the movement of the slip - off preventing member 23 . a bracket 29 shown in fig3 is fixed to the portion of the operating portion 41 on the side of the insertion portion 43 , and the bracket 29 fixes wire - receiving members 31 a and 31 b which allow the driving wires 25 a and 25 b to be movably inserted therethrough . the driving wires 25 a and 25 b fixed to the sleeves 21 a and 21 b , respectively , are inserted through the wire - receiving members 31 a and 31 b , respectively , push in the direction of the tip through a flexible portion 33 ( refer to fig1 ) of the insertion portion 43 , and are connected to a bending portion 71 at their ends . thereby , when the angle knob 55 a is rotated , the operating wires 17 a and 17 b are pushed or pulled by the pulley 13 , the driving wires 25 a and 25 b are pushed or pulled via the sleeves 21 a and 21 b correspondingly , and the bending portion 71 of the insertion portion 43 is bent in a predetermined direction . the angle knob 55 a bends the bending portion 71 right and left . on the other hand , the angle knob 55 b bends the bending portion 71 up and down . the pulley , operating wire , sleeve , and driving wire ( not shown ) as the above ones are connected to the angle knob 55 b , and these wire - connecting members are disposed at a lower layer of the connection structure shown in fig2 ( not shown ). in such connection structure , the slip - off preventing member 23 moves to a range within the sleeve 21 a , for example , when the operating wire 17 a is pushed toward the insertion portion 43 . this movement becomes a play , and consequently the smooth bending of the bending portion 71 is enabled . a coil spring 73 a or 73 b which cover wire surfaces are externally inserted onto the driving wire 25 a or 25 b between the wire - receiving member 31 a or 31 b and the sleeve 21 a or 21 b . as the coil springs 73 a and 73 b , for example , coil springs obtained by spirally winding a wire rod with a circular cross - section may be used . in this embodiment , the ends of the coil springs 73 a and 73 b become free ends which are not fixed only by covering the coil springs on the outer peripheries of the driving wires 25 a and 25 b . it is preferable that the internal diameter of the coil springs 73 a and 73 b be larger than a wire diameter to such an extent that sliding resistance with the driving wires 25 a and 25 b is not produced . additionally , it is preferable that a gap be formed between pitches of wound wire rods , i . e ., a structure where the springs may be retracted in an axial direction . fig5 is an explanatory view of the operation of the first embodiment . in the above configuration , for example , when the angle knob 55 a is operated and the pulley 13 is rotated counterclockwise , the lower operating wire 17 b is delivered to the right of fig5 , and the slip - off preventing members 23 moves to the right , and the sleeve 21 b moves to the right . at this time , the bending portion is bent , and accordingly , the upper operating wire 25 a is pulled from the insertion portion 43 ( refer to fig1 and 2 ). thereby , the driving wire 25 a pressed by the sleeve 21 a is introduced into the wire - receiving member 31 a , and is pushed to the insertion portion 43 . in this case , even if the reaction force of the push in the insertion portion 43 acts on the driving wire 25 a , and the driving wire 25 a is going to deflect , the outer periphery of the wire is covered with the coil spring 73 a between the wire - receiving member 31 a and the sleeve 21 a , and the deflection is regulated . if the distance between the wire - receiving member 31 a and the sleeve 21 a becomes shorter than the total length of the coil spring 73 a , the coil spring 73 a will cover the total length of the driving wire 25 a while being compressed . accordingly , according to the above endoscope 100 , the coil springs 73 a and 73 b are externally inserted onto the driving wires 25 a and 25 b between the wire - receiving members 31 a and 31 b , which are fixed to the portion of the operating portion 41 on the side of the insertion portion 43 and allows the driving wires 25 a and 25 b to be movably inserted therethrough , and the sleeves 21 a and 21 b . thus , when any one of the operating wires 17 a and 17 b on the side of the operating portion 41 is pushed toward the insertion portion 43 , the deflection is regulated because the outer peripheries of the wires are covered with the coil springs 73 a and 73 b even if the reaction force of the push acts on the driving wires 25 a and 25 b and any one of the driving wires 25 a and 25 b is going to deflect . thereby , with simple structure , meandering of the driving wires 25 a and 25 b may be prevented , and any damage of the wires may be prevented . next , a second embodiment of the endoscope according to the invention will be described . fig6 is an enlarged plan view of the inside of an operating portion according to the second embodiment to which coil springs are fixed , and fig7 is an explanatory view of the operation of the second embodiment . in addition , in the following respective embodiments , the same reference numerals will be given to the same members as the members shown in fig1 to 5 , and duplicate description will be omitted . in this endoscope , one ends ( left ends ) 73 a l and 73 b l of the coil springs 73 a and 73 b are fixed to the wire - receiving members 31 a and 31 b , respectively , and the other ends ( right ends ) 73 a r and 73 b r thereof are fixed to the sleeves 21 a and 21 b , respectively . according to this endoscope , both ends of the coil springs 73 a and 73 b are fixed to the wire - receiving members 31 a and 31 b and the sleeves 21 a and 21 b . thereby , even if the distance between the wire - receiving members 31 a and 31 b and the sleeves 21 a and 21 b changes with the push and pull operations of the wires , the length of the coil springs 73 a and 73 b makes a resilient change with this change , and the total wire lengths between the wire - receiving members 31 a and 31 b and the sleeves 21 a and 21 b are always covered with the coil springs 73 a and 73 b . in this embodiment , the fixation may be made with an initial tension being further given to the coil springs 73 a and 73 b . that is , both the coil springs 73 a and 73 b are made to have an initial tension and are fixed in an equilibrium state shown in fig6 such that the sleeves 21 a and 21 b are drawn toward the wire - receiving member 31 a and 31 b . in this case , as shown in fig7 , when the angle knob 55 a is operated and the operating wire 17 a is pushed to the left , the sleeve 21 a is pulled toward the wire - receiving member 31 a by the initial tension of the coil springs 73 a and 73 b , and the sleeve 21 a moves to the left . then , the slip - off preventing member 23 is kept abutting on the right end of the sleeve 21 a . thereby , a tension always acts on the operating wire 17 a , and thus , any deflection is not produced and meandering of the operating wire 17 a is prevented . in addition , although the coil spring 73 b pulls the sleeve 21 b in a direction reverse to its pushed direction , the operating force by the angle knob 55 a is sufficiently larger than this pull force , and therefore , there is no particular hindrance . next , a third embodiment of the endoscope according to the invention will be described . fig8 is an enlarged plan view the inside of an operating portion according to the third embodiment in which compression spring members are provided inside sleeves , respectively , fig9 is an explanatory view of the operation of the third embodiment , and fig1 is an explanatory view showing the operation of a compression spring member . in this endoscope , as shown in fig8 , compression spring members 75 a and 75 b which biases the slip - off preventing members 23 toward the operating wires 17 a and 17 b are provided inside the sleeves 21 a and 21 b , respectively . the compression spring members 75 a and 75 b may be coil springs which are housed in a compressed state . a left end of each spring member abuts on the engaging tube 65 , and the other end thereof abuts on the slip - off preventing member 23 . the compression spring members 75 a and 75 b may be proper spring members , such as leaf springs , besides the coil springs . according to this endoscope , as shown in fig9 , for example , when the operating wire 17 a is delivered and the driving wire 25 a is pushed via the sleeve 21 a , the slip - off preventing member 23 of the operating wire 17 a presses the compression spring member 75 a within the sleeve 21 a . when a pressing force on the side of the insertion portion ( left direction ) is applied to the slip - off preventing member 23 as shown in fig1 a , the driving wire 25 a is pushed while the compression spring member 75 a is once compressed as shown in fig1 b . almost simultaneously with stop of the extension , the sleeve 21 a is pulled back to the insertion portion ( left side ) as shown in fig1 c by the restoring force of the compression spring member 75 a , and a gap is eliminated between the slip - off preventing member 23 and the sleeve 21 a . thereby , as shown in fig1 d , the response when the operating wire 17 a is pulled toward the operating portion ( right side ) is increased . additionally even by this configuration , the sagging amount of the operating wire 17 a which is caused when the operating wire 17 a is pushed toward the insertion portion ( left side ) is absorbed as the slip - off preventing members 23 moves within the sleeve 21 a . in addition , although coil spring formed by spirally winding wire rods with a circular cross - section are used as the coil springs 73 a and 73 b in the above embodiment , the invention is not limited thereto , and other types of springs may also be applied . fig1 is a side view showing a modification of the coil spring . the coil spring may also be , for example , a coil spring 77 formed by spirally winding a strip material having a spring property shown in fig1 . by using the coil spring 77 made of such a strip material , the area of contact with the driving wires 25 a and 25 b may be increased , thereby guiding the driving wires 25 a and 25 b so as to more hardly deflect , and consequently , making it harder to cause meandering .
an endoscope includes an insertion portion which has a bending portion , a wire which is fixed to an end of a distal side of the bending portion and is pushed along the insertion portion , an operating portion which is provided on a proximal side of the insertion portion opposite to the bending portion , and a wire - connecting member which is interposed in the wire between the insertion portion and the operating portion to form an allowance in a in which the wire is pushed and pulled , wherein a portion of the wire between the wire - receiving member and the wire - connecting member is inserted into the coil spring so that the coil covers a surface of the portion of the wire .