Abstract:
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.

Description:
The present invention claims priority from Japanese Patent Application No. 2008-011323 filed on Jan. 22, 2008, the entire content of which is incorporated herein by reference. 
     BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope having a bending portion capable of being bent by wires, and particularly, to an improved technique of preventing meandering of the wires. 
     2. Description of the Related Art 
     An endoscope is composed roughly of an insertion portion inserted into an abdominal cavity or the like, and an operating portion to which a proximal end of this insertion portion is connected. In the insertion portion, a distal end including an image pick-up unit or the like, a bending portion which may be bent, and a long flexible portion which constitutes the proximal end of the insertion portion and is connected to the operation portion are sequentially connected toward the operating portion from the distal side. An operating mechanism for operating the bending portion provided in the insertion portion operates the bending portion by push and pull of wires which are arranged in a pair. As for the pair of wires, typically, a driving wire from the insertion portion and an operating wire from an angle knob that is an operating means are connected together within the operating portion (refer to JP-A-7-23892 JP-A-2003-290138). 
       FIG. 12  is a sectional view of an operating portion showing a connection structure in an endoscope. 
     A pulley  13  is provided inside an operating portion  11 , and the pulley  13  is fixed to an angle knob (not shown), which is rotatably provided at a side portion of the operating portion  11 , coaxially with a rotary shaft  15 . A pair of operating wires  17   a  and  17   b  is wound around the pulley  13 , and the operating wires  17   a  and  17   b  are pushed in the direction of the insertion portion  19 , and are connected to one ends of angular pipe-shaped sleeves  21   a  and  21   b  that are wire-connecting members  21 . Slip-off preventing members  23  (refer to  FIGS. 13A and 13B ) are respectively housed inside the sleeves  21   a  and  21   b  so as to be movable in an axial direction, and ends of the operating wires  17   a  and  17   b  are respectively connected to the slip-off preventing members  23 . 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  are respectively fixed to the other ends of the sleeves  21   a  and  21   b  by nut members  27 . A bracket  29  is fixed to the portion of the operating portion  11  on the side of the insertion portion  19 , 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  of the insertion portion  19 , and are connected to a bending portion (not shown) which becomes a distal end of the insertion portion  19 . Thereby, when the angle knob 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 of the insertion portion  19  is bent in a predetermined direction. 
     However, since the driving wires  25   a  and  25   b  and the operating wires  17   a  and  17   b  in the endoscope are connected via the sleeves  21   a  and  21   b  in the insertion portion  19 , and the wires are exposed as they are between the wire-receiving members  31   a  and  31   b  and the sleeves  21   a  and  21   b  and between the sleeves  21   a  and  21   b  and the pulley  13 , this connection structure is vulnerable to an axial compressive force. That is, as shown in  FIG. 13A , when delivery resistance is stronger at the insertion portion  19  than the wire-receiving members  31   a  and  31   b , the driving wires  25   a  and  25   b  between the wire-receiving member  31   a  and the sleeves  21   a  meandered due to deflection. On the other hand, as shown in  FIG. 13B , when the movement resistance of the sleeves  21   a  and  21   b  is great, the operating wire  17   a  between the sleeve  21   a  and the pulley  13  meandered due to deflection. If such meandering is repeated frequently, there is a probability that the wires may be damaged by fatigue. In contrast, it is also conceivable that the wires are housed in tubes having rigidity in order to regulate meandering. However, when regions where the wires become naked are eliminated, play may not be given to wire length, and the flexibility of the insertion portion  19  may not be maintained. Additionally, if the sleeves  21   a  and  21   b  are interposed, the lengths of the driving wires  25   a  and  25   b  between the wire-receiving members  31   a  and  31   b  and the sleeves  21   a  and  21   b  change with the movement of the sleeves  21   a  and  21   b . Therefore, the structure becomes complicated. 
     SUMMARY OF INVENTION 
     The invention is made in consideration of the above situations, and an object of the invention is to provide an endoscope capable of preventing meandering of a bending operating wire by simple structure, and thereby, preventing any damage of the wire. 
     The above object according to the invention is achieved by the following configurations. 
     According to a first aspect of the invention, 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, the operating portion configured to perform a push and pull operation of the wire, 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, a wire-receiving member which is arranged on an insertion-portion side of the operating portion, the wire being movably inserted through the wire-receiving member to be movable, and a coil spring, 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. 
     According to this endoscope, even if one of wires on the operating portion is pushed toward the insertion portion and the reaction force of the push acts on the wire, and the wire is going to deflect, the deflection of the wire is regulated because the outer periphery of the wire is covered with the coil spring between the wire-receiving member and the wire-connecting member. Thereby, meandering of the wire between the wire-receiving member and the wire-connecting member is prevented. 
     According to a second aspect of the invention, one end of the coil spring is fixed to the wire-receiving member, and the other end of the coil spring is fixed to the wire-connecting member. 
     According to this endoscope, both ends of the coil spring are fixed to the wire-receiving member and the wire-connecting member. Thereby, even if the distance between the wire-receiving member and the wire-connecting member changes with the push and pull operations of the wire, the length of the coil spring makes a resilient change with this change, and the total wire length between the wire-receiving member and the wire-connecting member is always covered with the coil spring. 
     According to a third aspect of the invention, the coil spring is fixed in a state where an initial tension is given thereto. 
     According to this endoscope, the wire-connecting member is pulled toward the wire-receiving member by the initial tension of the coil spring, and a tension always acts on the wire on the side of the operating portion, thereby eliminating any deflection in the wire. This prevents meandering of the operating wire. 
     According to a forth aspect of the invention, the wire-connecting member connects a driving wire portion that is the wire on the insertion-portion side, and an operating wire portion that is the wire on an operating-portion side together, and wherein the wire-connecting member includes, a sleeve connected to an end of the driving wire portion, and a slip-off preventing member that is connected to the operating wire, is movable in the direction of push and pull within the sleeve, and is accommodated in the sleeve, and the sleeve and the split-off preventing member form a slip-off preventing structure that prevents the operating wire from slipping off from the sleeve. 
     According to this endoscope, the slip-off preventing member moves to a range within the sleeve when the operating wire is pushed toward the insertion portion. This movement becomes a play, and consequently the flexibility of the insertion portion is maintained. 
     According to a fifth aspect of the invention, a compression spring member arranged within the sleeve and biased the slip-off preventing member toward the operating wire. 
     According to this endoscope, when the operating wire is pushed, and the driving wire is pushed via the wire-connecting member, the slip-off preventing member of the operating wire presses and compresses the compression spring member within the wire-connecting member. Additionally, since the compression spring member pushes the slip-off preventing member back to the operating portion by its restoring force when operation is stopped, a gap is eliminated between the slip-off preventing member and the wire-connecting member. This enhances the response when the operating wire is pulled. Additionally, even when the operating wire is pushed toward the insertion portion, the slip-off preventing member may move within the wire-connecting member to absorb the amount of sagging of the driving wire. 
     According to the endoscope related to the invention, when a wire on the operating portion is pushed toward the insertion portion, the deflection of the wire is regulated because the outer periphery of the wire is covered with the coil spring between the wire-receiving member and the wire-connecting member even if the reaction force of the extension acts on the wire, and the wire is going to deflect. Thereby, with simple structure, meandering of the bending operating wire may be prevented, and any damage of the wire may be prevented. 
     Other aspects and advantages of the invention will be apparent from the following description and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an entire configuration diagram of an endoscope according to a first embodiment of the invention; 
         FIG. 2  is a partially cutaway perspective view of an operating portion shown in  FIG. 1 ; 
         FIG. 3  is an enlarged plan view of the inside of the operating portion shown in  FIG. 2 ; 
         FIG. 4  is a sectional view of a sleeve; 
         FIG. 5  is an explanatory view of the operation of the first embodiment; 
         FIG. 6  is an enlarged plan view of the inside of an operating portion according to a second embodiment to which coil springs are fixed; 
         FIG. 7  is an explanatory view of the operation of the second embodiment; 
         FIG. 8  is an enlarged plan view of the inside of an operating portion according to a third embodiment in which compression spring members are provided inside sleeves, respectively; 
         FIG. 9  is an explanatory view of the operation of the third embodiment; 
         FIG. 10A  is an explanatory view showing the operation of a compression spring member; 
         FIG. 10B  is an explanatory view showing the operation of a compression spring member; 
         FIG. 10C  is an explanatory view showing the operation of a compression spring member; 
         FIG. 10D  is an explanatory view showing the operation of a compression spring member; 
         FIG. 11  is a side view showing a modification of the coil spring; 
         FIG. 12  is a plan view of the inside of an operating portion in an endoscope; 
         FIG. 13A  is a plan view of the inside of the operating portion, showing a wire meandering situation; and 
         FIG. 13B  is a plan view of the inside of the operating portion, showing a wire meandering situation. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferred embodiments of an endoscope according to the invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is an entire configuration diagram of an endoscope according to a first embodiment of the invention, and  FIG. 2  is a partially cutaway perspective view of an operating portion shown in  FIG. 1 . In addition, description will be made with the same reference numerals being given to the same members as the members shown in  FIG. 12 . 
     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 . 
       FIG. 3  is an enlarged plan view of the inside of the operating portion shown in  FIG. 2 . 
     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. 
       FIG. 4  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  FIG. 3  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  FIG. 1 ) 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  FIG. 2  (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. 
       FIG. 5  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  FIG. 5 , 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  FIGS. 1 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. 
       FIG. 6  is an enlarged plan view of the inside of an operating portion according to the second embodiment to which coil springs are fixed, and  FIG. 7  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  FIGS. 1 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  FIG. 6  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  FIG. 7 , 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. 
       FIG. 8  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,  FIG. 9  is an explanatory view of the operation of the third embodiment, and  FIG. 10  is an explanatory view showing the operation of a compression spring member. 
     In this endoscope, as shown in  FIG. 8 , 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  FIG. 9 , 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  FIG. 10A , the driving wire  25   a  is pushed while the compression spring member  75   a  is once compressed as shown in  FIG. 10B . 
     Almost simultaneously with stop of the extension, the sleeve  21   a  is pulled back to the insertion portion (left side) as shown in  FIG. 10C  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  FIG. 10D , 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.  FIG. 11  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  FIG. 11 . 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.