Patent Publication Number: US-2009234188-A1

Title: Medical apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation Application of PCT Application No. PCT/JP2007/072306, filed Nov. 16, 2007, which was published under PCT Article 21(2) in Japanese. 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2006-315721, filed Nov. 22, 2006; No. 2006-327417, filed Dec. 4, 2006; and No. 2006-333533, filed Dec. 11, 2006, the entire contents of all of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a medical apparatus including a hollow member with inner surface parts configured to be brought into contact with each other through deformation of the hollow member. 
     2. Description of the Related Art 
     In a medical apparatus, various hollow members are used whose inner surface parts are configured to be bought into contact with each other through deformation thereof. As the hollow member, there is a fluid transferring tube disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-308786. The fluid transferring tube is configured to be closed when it is pressed in a valve and opened when the pressing is released. Moreover, as the hollow member, there is a balloon of an insertion instrument for an endoscope disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-301019. The insertion instrument for the endoscope is adapted to assist an insertion of the endoscope into a cavity in the body. An insertion instrument main part has a shape of a sheath, and the endoscope is inserted through the inner cavity of the insertion instrument main part so as to be movable forward and backward. The balloon is provided on the outside of the distal end portion of the insertion instrument main part, and it is possible for the balloon to hold the inner surface of the cavity in the body by expanding the balloon. 
     BRIEF SUMMARY OF THE INVENTION 
     In an aspect of the present invention, a medical apparatus includes a hollow member whose inner surface parts are configured to be brought into contact with each other through deformation of the hollow member, and the hollow member includes a convex and concave portion formed on the inner surface parts configured to be brought into contact with each other. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a view showing a medical apparatus according to a first embodiment of the present invention; 
         FIG. 2  is a view showing an endoscope and an insertion instrument according to the first embodiment of the present invention; 
         FIG. 3A  is a view showing the inner surface of a balloon according to the first embodiment of the present invention; 
         FIG. 3B  is a longitudinal cross sectional view showing the balloon according to the first embodiment of the present invention; 
         FIG. 4A  is a view showing the inner surface of the balloon according to a first variation example of the first embodiment of the present invention; 
         FIG. 4B  is a longitudinal cross sectional view showing the balloon according to the first variation example of the first embodiment of the present invention; 
         FIG. 5A  is a view showing the inner surface of a balloon according to a second variation example of the first embodiment of the present invention; 
         FIG. 5B  is a longitudinal cross sectional view showing the balloon according to the second variation example of the first embodiment of the present invention; 
         FIG. 6A  is a view showing the inner surface of a balloon according to a third variation example of the first embodiment of the present invention; 
         FIG. 6B  is a transverse cross sectional view showing the balloon according to the third variation example of the first embodiment of the present invention; 
         FIG. 7  is a view showing the inner surface of a balloon according to a fourth variation example of the first embodiment of the present invention; 
         FIG. 8  is a schematic view showing a method for producing a balloon according to the first embodiment of the present invention; 
         FIG. 9A  is a perspective view showing the balloon in an expanding state according to the first embodiment of the present invention; 
         FIG. 9B  is a perspective view showing the balloon in a contracting state according to the first embodiment of the present invention; 
         FIG. 9C  is a transverse cross sectional view showing the balloon in the contracting state according to the first embodiment of the present invention; 
         FIG. 10  is a perspective view showing a tube according to the first embodiment of the present invention; 
         FIG. 11  is a transparent perspective view showing a tube according to a variation example of the first embodiment of the present invention; 
         FIG. 12A  is a cross sectional view showing a electromagnetic valve in the state where the electromagnetic valve closes an air discharging pass according to the first embodiment of the present invention; 
         FIG. 12B  is a cross sectional view showing the electromagnetic valve in the state where the electromagnetic valve closes an air supplying pass according to the first embodiment of the present invention; 
         FIG. 13  is a longitudinal cross sectional view showing a balloon according to a third embodiment of the present invention; 
         FIG. 14  is a longitudinal cross sectional view showing a balloon according to a variation example of the third embodiment of the present invention; 
         FIG. 15A  is a schematic view showing a supplying and discharging apparatus according to a fourth embodiment of the present invention; 
         FIG. 15B  is a schematic view showing a supplying and discharging apparatus according to a variation example of the fourth embodiment of the present invention; 
         FIG. 16  is a schematic view showing a supplying and discharging apparatus according to a fifth embodiment of the present invention; 
         FIG. 17  is a partially cross sectional side view showing an insertion instrument according to a sixth embodiment of the present invention; 
         FIG. 18A  is a partially cross sectional side view showing a proximal end portion of an insertion instrument according to the sixth embodiment of the present invention; 
         FIG. 18B  is a partially cross sectional side view showing a proximal end portion of an insertion instrument according to a comparison embodiment with the sixth embodiment of the present invention; 
         FIG. 19  is a partially cross sectional side view showing an insertion instrument according to a first variation example of the sixth embodiment of the present invention; 
         FIG. 20  is a perspective view showing an insertion instrument according to a second variation example of the sixth embodiment of the present invention; 
         FIG. 21  is a partially cross sectional side view showing an insertion instrument according to a seventh embodiment of the present invention; 
         FIG. 22A  is a longitudinal cross sectional view showing a distal end portion of an insertion instrument according to a reference embodiment of the present invention; 
         FIG. 22B  is a front view showing the distal end portion of the insertion instrument according to a reference embodiment of the present invention; 
         FIG. 23  is partially cross sectional side view showing an endoscope and an insertion instrument according to an eighth embodiment of the present invention; 
         FIG. 24  is a partially cross sectional side view showing an endoscope and an insertion instrument according to a ninth embodiment of the present invention; 
         FIG. 25  is a partially cross sectional side view showing an endoscope and an insertion instrument according to a tenth embodiment of the present invention; 
         FIG. 26  is a side view showing an endoscope and an insertion instrument according to an eleventh embodiment of the present invention; 
         FIG. 27  is a perspective view showing a proximal end portion of an insertion instrument according to a twelfth embodiment of the present invention; 
         FIG. 28  is a perspective view showing a proximal end portion of an insertion instrument according to a thirteenth embodiment of the present invention; and 
         FIG. 29  is a perspective view showing a proximal end portion of an insertion instrument according to a fourteenth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a first to a fourth embodiment of the present invention will be described referring to the drawings. 
       FIGS. 1 to 12B  show the first embodiment of the present invention. 
     Referring to  FIGS. 1 and 2 , an endoscope  30  of an endoscope apparatus according to the present embodiment includes an elongate insertion portion  31  configured to be inserted into a cavity in the body. The insertion portion  31  is formed of a distal end rigid portion  32  having rigidity, a bending portion  33  configured to be operated to be bent and an insertion tube portion  34  being long and flexible coupled to each other in the order from the distal end side. The proximal end portion of the insertion portion  31  is coupled to an operation portion  36  through a bending preventing portion  35 , and the operation portion  36  is configured to be held and operated by an operator. The bending preventing portion  35  is configured to prevent the insertion portion  31  from bending in the coupling part between the insertion portion  31  and the operation portion  36 , and has a tapering shape whose outer diameter is reduced from the proximal end side to the distal end side. The operation portion  36  is provided with a bending operation knob to operate the bending portion  33 , and the like. A universal cable  38  extends from the operation portion  36 , and the extended end portion of the universal cable  38  is provided with a light source connecter  39  and an electric connecter  42 . The light source connecter  39  is configured to be connected to a light source apparatus  40 , and illumination light from the light source apparatus  40  is to be transmitted through a light guide extending from the light source connecter  39  to the distal end portion of the endoscope  30  and emitted from the distal end portion of the endoscope  30 . The electric connecter  42  is configured to be connected to a video processor  46  through an electric cable  44 , and an image signal obtained in an image pick-up unit in the distal end portion of the endoscope  30  is output to the video processor  46  through a signal cable and the electric cable  44  extending from the distal end portion of the endoscope  30  to the electric connecter  42 . The video processor  46  is configured to process the input image signal and displays an observation image in a monitor  48 . The operation portion  36  of the endoscope  30  is provided with various kinds of switch  50  to operate the video processor  46 . 
     On the other hand, an insertion instrument  52  of the endoscope apparatus according to the present embodiment includes an insertion instrument main part  53  being soft and having a shape of a sheath. The insertion portion  31  of the endoscope  30  is to be inserted through the inner cavity of the insertion instrument main part  53  from the proximal end opening to the distal end opening so as to be movable forward and backward. The distal end portion of the insertion instrument main part  53  is provided with a distal end cap  54 . The distal end portion of the insertion portion  31 , which is consisted of the distal end rigid portion  32  and the bending portion  33 , is to be projected from the distal end opening of the insertion instrument main part  53 . A tapering portion  55  is formed in the proximal end portion of the inner cavity of the insertion instrument main part  53 , and the inner diameter of the tapering portion  55  is reduced from the proximal end side to the distal end side. When the insertion portion  31  and then the bending preventing portion  35  of the endoscope  30  are inserted into the proximal end opening of the insertion instrument main part  53  and the tapering portion  55  of the insertion instrument main part  53  and the bending preventing portion  35  of the endoscope  30  are fitted to each other, the insertion instrument  52  and the endoscope  30  are fixed to each other. 
     The proximal end portion of the insertion instrument main part  53  is provided with a liquid connecter  56 , and a liquid supplying pass  57  as a liquid transferring pass extends from the liquid connecter  56  to the inner cavity of the insertion instrument main part  53 . A cylinder  51  and so on as a liquid transfer apparatus is configured to supply a lubricant from the liquid connecter  56  through the liquid supplying pass  57  to the inner cavity of the insertion instrument main part  53 . The lubricant is adapted to improve a sliding capability between the inner peripheral surface of the insertion instrument  52  and the outer peripheral surface of the insertion portion  31 . 
     The proximal end portion of the insertion instrument main part  53  is provided with the gas connecter  58 , a gas supplying and discharging pass  59  as a gas transferring pass extends from the gas connecter  58  to a balloon  60  as a hollow member, and the balloon  60  is provided on the outside of the distal end portion of the insertion instrument main part  53 . The balloon  60  has a substantially cylindrical shape, and both the end parts  61   a  of the balloon  60  is bonded and fixed to the outer peripheral surface of the insertion instrument main part  53 . The middle part  61   b  of the balloon  60  is configured to be expanded and contracted by supplying and discharging a gas from and to the gas connecter  58  through the gas supplying and discharging pass  59  to and from the balloon  60 . 
     One end portion of an outer tube  62  as a fluid transferring tube and a gas tube is detachably connected to the gas connecter  58 , and the other end portion of the outer tube  62  is detachably connected to a supplying and discharging apparatus  63  as a gas transferring apparatus. An inner tube  64  as a fluid transferring tube is provided within the supplying and discharging apparatus  63 . The outer tube  62  and the inner tube  64  are made of material having elasticity, for example, silicon, polyurethane, or vinyl chloride. One end side of the inner tube  64  forms a common pass  64   a  and is fluidly communicated to the outer tube  62 . On the other hand, the other end side of the inner tube  64  is branched into an air supplying pass  64   b  and an air discharging pass  64   c . The air supplying pass  64   b  and the air discharging pass  64   c  are configured to be selectively opened and closed by an electromagnetic valve  65 . The air supplying pass  64   b  is connected to an air supplying pump of a pump unit  66  and the air discharging pass  64   c  is connected to an air discharging pump of the pump unit  66 . The electromagnetic valve  65  and the pump unit  66  are controlled by a control circuit  67 , and a remote controller  68  is connected to the supplying and discharging apparatus  63  and configured to input an operation signal to the control circuit  67 . 
     Referring to  FIGS. 3A to 8 , the balloon  60  provided on the outside of the distal end portion of the insertion instrument main part  53  will be explained in detail. 
     A convex and concave portion  70  is formed on the inner surface of the middle part  61   b  of the balloon  60  configured to be expanded and contracted. When the balloon  60  is contracted and the inner surface parts of the balloon  60  are brought into contact with each other, the convex and concave portion  70  reduces contact area to prevent adhesion between the inner surface parts of the balloon  60 . The convex and concave shape of the convex and concave portion  70  may be any shape adapted to reduce the contact area between the inner surface parts of the balloon  60 . Hereinafter, examples of the convex and concave shape will be described. 
     In a balloon  60  as shown in  FIGS. 3A and 3B , a large number of semi-spherical convex shapes  72   a  are formed on the inner surface of the middle part  61   b  of the balloon  60 . 
     In a balloon  60  as shown in  FIGS. 4A and 4B , elongate convex shapes  72   b  are formed into a grid pattern on the inner surface of the middle part  61   b  of the balloon  60 . 
     In a balloon  60  as shown in  FIGS. 5A and 5B , regular quadrangular pyramid-like convex shapes  72   c  are arranged side by side longitudinally and transversely on the inner surface of the middle part  61   b  of the balloon  60 . 
     In a balloon  60  as shown in  FIGS. 6A and 6B , elongate convex shapes  72   d  are arranged side by side and extend in the longitudinal direction on the inner surface of the middle part  61   b  of the balloon  60 . 
     In a balloon  60  as shown in  FIG. 7 , a pear-skin-like convex and concave portion  70  is formed on the inner surface of the middle part  61   b  of the balloon  60 . 
     Referring to  FIG. 8 , a method for producing a balloon  60  will be explained. 
     A case will be explained as an example, where a balloon  60  as shown in  FIGS. 3A and 3B  is produced through dip molding. A die  74  is prepared, whose shape of the outer surface corresponds to the shape of the inner surface of the balloon  60 . That is, the die  74  is formed of both circularly columnar portions  75  on both end parts thereof and an expanding portion  76  whose outer diameter is increased on a middle part thereof. In the expanding portion  76 , a large number of semi-spherical concave shapes  77  corresponding to the convex shapes  72   a  of the balloon  60  are formed, and the convex and concave shape obtained by reversing the convex and concave shape of the balloon  60  is formed. The die  74  is dipped into liquid silicon rubber  79  and then taken out, and the liquid silicon rubber  80  attached to the outer surface of the die  74  is dried. After that, the die  74  is taken from the dried silicon rubber, and the balloon  60  is formed where the convex and concave shape is transferred to the inner surface of the middle part  61   b  of the balloon  60 . Other than such dip molding, the convex and concave shape may be transferred to the inner surface of the balloon  60  through pressing. 
     Next, an adhesion preventing function of the balloon  60  will be explained. 
     As is shown in  FIG. 9A , when the balloon  60  is expanded, the inner surface parts of the balloon  60  are separated from each other. On the other hand, as is shown in  FIGS. 9B and 9C , when the balloon  60  is contracted, the outer wall parts of the balloon  60  are overlapped with each other to form overlaped parts  85 , the overlaped parts  85  are arranged side by side in the peripheral direction and extend in the longitudinal direction, and the inner surface parts of the balloon  60  are brought into contact with each other in the overlapping parts  85 . Therefore, there is a possibility that the inner surface parts of the balloon  60  are adhered to each other. In particular, the balloon  60  is kept contracted for a long time while the medical apparatus is not used, the inner surface parts of the balloon  60  are kept in contact with each other for a long time, and there is a high possibility of adhesion. In the balloon  60  according to the present embodiment, the convex and concave portion  70  is formed on the inner surface parts configured to be brought into contact with each other when the balloon  60  is contracted, and therefore, contact area of the inner surface parts is reduced, whereby preventing adhesion. 
     Referring to  FIGS. 10 and 11 , the outer tube  62  and the inner tube  64  will be explained in detail. 
     A convex and concave portion  70  is formed on the inner surface of the tube  62  or  64 . The convex and concave portion  70  is configured to reduce contact area to prevent the inner surface parts of the tube  62  or  64  from being adhered to each other when the tube  62  or  64  is closed and the inner surface parts of the tube  62  or  64  are brought into contact with each other. The convex and concave shape of the convex and concave portion  70  may be any shape adapted to reduce contact area between the inner surface parts of the tube  62  or  64 . Hereinafter, examples of the convex and concave shape will be described. 
     In a tube  62  or  64  as shown in  FIG. 10 , a large number of elongate convex shapes  84   a  extend in the longitudinal direction and arranged side by side in the peripheral direction. 
     In a tube  62  or  64  as shown in  FIG. 11 , elongate convex shapes  84   b  helically extend in the longitudinal direction. 
     Next, an adhesion preventing function of the outer tube  62  or the inner tube  64  will be explained. 
     The outer tube  62  is located outside, and therefore, the outer tube  62  may be bent or crushed to be closed and the inner surface parts of the outer tube  62  may be brought into contact with each other. Therefore, there is a possibility that the inner surface parts of the outer tube  62  are adhered to each other. In particular, in the case where the outer tube  62  is kept in storage in the state where the outer tube  62  is bent or crushed while the medical apparatus is not used, the inner surface parts of the outer tube  62  is kept in contact with each other for a long time, and therefore, there is a high possibility of adhesion. In the outer tube  62  according to the present embodiment, the convex and concave portion  70  is formed on the inner surface parts configured to be brought into contact with each other when the outer tube  62  is closed, and therefore, contact area between the inner surface parts is reduced, whereby preventing adhesion. 
     As is shown in  FIG. 12A , when expanding the balloon  60 , in the supplying and discharging apparatus  63 , a pressing portion  86  of the electromagnetic valve  65  presses the air discharging pass  64   c  of the inner tube  64  to be closed, while the air supplying pass  64   b  of the inner tube  64  is kept opened. On the other hand, as is shown in  FIG. 12B , when contracting the balloon  60 , in an supplying and discharging apparatus  63 , the pressing portion  86  of the electromagnetic valve  65  presses the air supplying pass  64   b  of the inner tube  64  to be closed, while the air discharging pass  64   c  of the inner tube  64  is kept opened. 
     Here, when the air discharging pass  64   c  of the inner tube  64  is closed, the inner surface parts of the inner tube  64  are brought into contact with each other in the air discharging pass  64   c , and also, when the air supplying pass  64   b  of the inner tube  64  is closed, the inner surface parts of the inner tube  64  are brought into contact with each other in the air supplying pass  64   b . Therefore, there is a possibility that the inner surface parts of the inner tube  64  are adhered to each other. In particular, the air supplying pass  64   b  is closed to contract the balloon  60  at the end of using of the medical apparatus, and therefore, while the medical apparatus is not used, the air supplying pass  64   b  is kept closed and the inner surface parts of the inner tube  64  are in contact with each other in the air supplying pass  64   b  for a long time. Therefore, there is a high possibility of adhesion. In the inner tube  64  according to the present embodiment, the convex and concave portion  70  is formed on the inner surface parts configured to be brought into contact with each other when the inner tube  64  is closed, and therefore, contact area between the inner surface parts is reduced, whereby preventing adhesion. 
     The medical apparatus according to the present embodiment exhibits the following effects. 
     In the medical apparatus according to the present embodiment, the convex and concave portion  70  formed on the inner surface parts of the balloon  60 , the outer tube  62  and the inner tube  64  reduces contact area between the inner surface parts, whereby preventing adhesion between the inner surface parts. 
     In particular, the balloon  60  tends to adhere because the balloon  60  is made of elastic material which tends to adhere, for example, silicon, polyurethane or vinyl chloride and also the inner surface parts of the balloon  60  are brought into contact with each other when the balloon  60  is contracted. The outer tube  62  tends to adhere because the outer tube  62  is made of material which tends to adhere as is similar to the balloon  60  and also the outer tube  62  is soft and has a small diameter, and is configured to be easily closed to bring the inner surface parts of the outer tube  62  in contact with each other. The inner tube  64  tends to adhere because the inner tube  64  is made of material which tends to adhere as is similar to the balloon  60  and the outer tube  62  and also the inner surface parts of the inner tube  64  is configured to be pressed to each other by the electromagnetic valve  65 . The convex and concave portion  70  is applied to such balloon  60 , outer tube  62  and inner tube  64 , and therefore, the adhesion preventing effect is remarkably exhibited. 
     Moreover, the convex and concave portion  70  is applied to the inner tube  64  within the supplying and discharging apparatus  63  to prevent adhere, which it is troublesome to exchange in the case of adhesion, and therefore, it is easy to maintain the supplying and discharging apparatus  63 . 
     Referring again to  FIGS. 1 and 2 , the second embodiment of the present invention will be explained. 
     In a medical apparatus according to the present embodiment, a convex and concave portion  70  is formed over the whole inner surface of an insertion instrument main part  53  as a hollow member. The insertion instrument main part  53  is elongate and soft, and therefore, the insertion instrument main part  53  may be bent or crushed to be closed to bring the inner surface parts thereof into contact with each other to be adhered. In particular, in the case where the insertion instrument main part  53  is kept in storage in the state where the insertion instrument main part  53  is bent or crushed while the medical apparatus is not used, the inner surface parts of the insertion instrument main part  53  is kept in contact with each other for a long time, and therefore, it is a high possibility of adhesion. In the present embodiment, the convex and concave portion  70  is formed on the inner surface parts of the insertion instrument main part  53  configured to be brought into contact with each other when the insertion instrument main part  53  is closed, and therefore, contact area between the inner surface parts is reduced, whereby preventing adhesion. In addition, when inserting an insertion portion  31  of an endoscope  30  through the insertion instrument main part  53  and moving forward and backward the insertion portion  31 , the convex and concave portion  70  of the inner surface of the insertion instrument main part  53  reduces contact area and therefore friction resistance between the inner surface of the insertion instrument main part  53  and the outer surface of the insertion portion  31 , and therefore, it is possible to smoothly move forward and backward the insertion portion  31 . 
     Moreover, in the case where the insertion portion  31  and then a bending preventing portion  35  of the endoscope  30  is inserted into the proximal end opening of the insertion instrument main part  53  and the bending preventing portion  35  is fitted to a tapering portion  55  of the proximal end portion of the insertion instrument main part  53 , the inner surface of the tapering portion  55  and the outer surface of the bending preventing portion  35  is kept pressed, and therefore, there is a possibility of adhesion. In particular, in the case where an insertion instrument  52  and the endoscope  30  is kept in standby for a long time in the state where the insertion instrument  52  and the endoscope  30  are fixed to each other, the inner surface of the tapering portion  55  and the outer surface of the bending preventing portion  35  is kept pressed for a long time, and therefore, there is a high possibility of adhesion. In the present embodiment, the convex and concave portion  70  is formed on the tapering portion  55  at the proximal end portion of the insertion instrument main part  53 , and therefore, contact area between the inner surface of the tapering portion  55  and the outer surface of the bending preventing portion  35  is reduced, whereby preventing adhesion. 
       FIG. 13  shows a third embodiment of the present invention. 
     As is mentioned above, adhesion between the inner surface parts is prevented in the case where a convex and concave portion  70  is formed on the inner surface parts configured to be brought into contact with each other, on the other hand, a bonding effect is improved in the case where the convex and concave portion  70  is formed on a surface to be bonded. Referring to  FIGS. 1 ,  2  and  13 , in a balloon  60  according to the present embodiment, the convex and concave portion  70  is also formed on the inner surface  88  of both end parts  61   a  configured to be bound to be fixed to an insertion instrument main part  53  as well as the inner surface of a middle part  61   b  configured to be expanded and contracted, whereby improving a bonding effect between the insertion instrument main part  53  and the balloon  60 . 
       FIG. 14  shows a variation example of the third embodiment of the present invention. 
     Referring to  FIGS. 1 ,  2  and  14 , in a balloon  60  according to the present embodiment, both end parts  61   a  of a balloon  60  are fitted on the outside of the insertion instrument main part  53 , silk gut  91  is wound around and fixed to by bonding agent the outer peripheral surface of both the end parts  61   a  of the balloon  60 , and both the end portions of the balloon  60  are fixed to the insertion instrument main part  53 . Here, a convex and concave portion  70  is formed on the outer peripheral surface  90  of both the end portions of the balloon  60 , whereby improving a bonding effect between the balloon  60  and the silk gut  91 . 
       FIG. 15A  shows a fourth embodiment of the present invention. 
     In a medical apparatus according to the present embodiment, a convex and concave portion  70  is not formed on the inner surface of an outer tube  62 , differing from the first embodiment. The outer tube  62  is connected to an inner tube  64  through a liquid saving tank  92  adapted to collect a contamination as a contamination removing mechanism. The liquid saving tank  92  may be replaced by a filter adapted to separate a gas and a liquid. The inner tube  64  is put out of the liquid saving tank  92  and put into a supplying and discharging apparatus  63  through a connecting portion  93 . In the supplying and discharging apparatus  63 , a main pass  94  of the inner tube  64  branches into a first branch pass  94   a  and further branches into a second branch pass  94   b . A pressure sensor  96  is interposed into the main pass  94  more downstream than the second branch pass  94   b . Furthermore, the main pass  94  branches into a third branch pass  94   c  and a fourth branch pass  94   d . The third branch pass  94   c  is connected to a pump unit  66 , and a fifth branch pass  94   e  is branched from the third branch pass  94   c  on the upper side of the pump unit  66 . On the other hand, the fourth branch pass  94   d  is connected to the pump unit  66 , and the sixth branch pass  94   f  is branched from the fourth branch pass  94   d  on the upper side of the pump unit  66 . A first to a sixth electromagnetic valve  65   a ,  65   b ,  65   c ,  65   d ,  65   e ,  65   f  is interposed into the first to the sixth branch pass  94   a  . . .  94   f , respectively. 
     The medical apparatus according to the present embodiment, even when the supplying and discharging apparatus  63  suctions a contamination by mistake, the liquid saving tank  92  collects the contamination, and therefore, the contamination is prevented from entering into the inner tube  64 . Therefore, the inner tube  64  is not contaminated and it is enough to exchange the only outer tube  62 . That is, it is unnecessary to frequently exchange the inner tube  64  whose inner surface is provided with the convex and concave portion  70  and which is relatively expensive in comparison with the outer tube  62  whose inner surface is not provided with the convex and concave portion  70  and which is relatively inexpensive, and it is possible to inexpensively maintain the medical apparatus. 
     As shown in  FIG. 15B , a liquid saving tank  92  and a supplying and discharging apparatus  63  may be connected to each other through a connecting tube  97 , and the one end portion of the connecting tube  97  may be configured to be attached to and detached from a connecting portion  93  to the supplying and discharging apparatus  63 . Here, a convex and concave portion  70  is not formed on the inner surface of the connecting tube  97 , and the convex and concave portion  70  is formed on the only inner surface of the inner tube  64  within the supplying and discharging apparatus  63 . 
       FIG. 16  shows a fifth embodiment of the present invention. 
     In a supplying and discharging apparatus  63  according to the present embodiment, a convex and concave portion  70  is formed on the inner surface of a processed tube  98 , and the processed tube  98  is used in an only part configured to be closed by the electromagnetic valve  65 . Both the end portions of the processed tube  98  are connected through the coupling tube  100  to normal tubes  102  whose inner surface is not provided with the convex and concave portion  70 , respectively. Instead of using the coupling tube  100 , the processed tube  98  and the normal tube  102  may be bonded or welded to each other. 
     In the present embodiment, the processed tube  98  whose inner surface is provided with the convex and concave portion  70  and which is relatively expensive is used in the only part configured to be closed by the electromagnetic valve  65 , the normal tubes  102  whose inner surface are not provided with the convex and concave portion  70  and which are relatively inexpensive are used in the other parts, and therefore, it is possible to inexpensively form the whole medical apparatus. 
     Hereinafter, a sixth and a seventh embodiment of the present invention, and a reference embodiment thereof will be explained referring to the drawings. 
     The sixth and the seventh embodiment relates to an insertion instrument adapted to assist an insertion of the endoscope into a cavity in the body. 
     When an insertion portion of an endoscope is inserted into a cavity in the body, an insertion instrument adapted to assist the insertion of the insertion portion is used. 
     In Jpn. Pat. Appln. KOKAI Publication No. 2004-329720, an overtube as the insertion instrument is disclosed. The insertion portion of the endoscope is inserted through the overtube so as to be movable forward and backward. When inserting the insertion portion into the overtube, water as a lubricant is injected into the inner cavity of the overtube from a water injecting inlet on the proximal end portion of the overtube whereby improving a sliding capability between the inner surface of the overtube and the outer surface of the insertion portion to improve an inserting capability. Then, in the state where the insertion portion is inserted through the overtube, the overtube and the insertion portion are inserted into a cavity in the body, and then, the overtube and the insertion portion are alternately moved forward to be inserted into a deep portion of the cavity in the body. If necessary, air is supplied to and discharged from a balloon provided on the distal end portion of the overtube through an air supplying tube extending in the longitudinal direction of the overtube from and to an air sending inlet provided on the proximal end portion of the overtube, and therefore, the balloon is expanded to hold the inner surface of the cavity in the body and contracted to release the holding. 
     In the insertion instrument disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2004-329720, water is to be supplied into the inner cavity from the water injection inlet, and also, air is to be supplied to and discharged from the balloon from and to the air sending inlet. In order to smoothly and easily carry out the transfer of the fluid, it is preferable that resistance in the transfer of the fluid is small. 
     The sixth and the seventh embodiment have been made in view of the above mentioned problem and are directed to provide an insertion instrument wherein it is possible to transfer a fluid at small resistance. 
     An endoscope apparatus and an insertion instrument according to the sixth and the seventh embodiment, and the reference embodiment thereof include substantially similar structures to those of the endoscope apparatus according to the first embodiment as shown in  FIGS. 1 and 2 , and the insertion instrument according to the second embodiment explained referring to  FIGS. 1 and 2 . Hereinafter, configurations differing from the first and the second embodiment will be explained in details. 
       FIGS. 17 to 18B  show the sixth embodiment of the present invention. 
     Referring to  FIG. 17 , a liquid connecter  56  and a gas connecter  58  will be explained in detail. 
     A protruding direction R of the liquid connecter  56  forms a first inclination angle θ 1  with respect to the longitudinal direction P of an insertion instrument main part  53  of the insertion instrument  52  toward the distal end side. On the other hand, a protruding direction T of the gas connecter  58  forms a second inclination angle θ 2  with respect to the longitudinal direction P of the insertion instrument main part  53  toward the distal end side. The second inclination angle θ 2  of the gas connecter  58  is smaller than the first inclination angle θ 1  of the liquid connecter  56 . That is, regarding a liquid supplying pass  57 , the inclination angle θ 1  of the liquid connecter  56  is relatively large, the total length of the liquid supplying pass  57  having a shape of a substantially straight line and extending from the protruding end of the liquid connecter  56  to the inner cavity of the insertion instrument main part  53  is short, and conduit resistance over the whole liquid supplying pass  57  is small. On the other hand, a gas supplying and discharging pass  59  extends along the longitudinal direction (the protruding direction) of the gas connecter  58 , and then, extends along the longitudinal direction of the insertion instrument main part  53  to reach a balloon  60 . That is, the gas supplying and discharging pass  59  forms a bending part  103  from the root end portion of the gas connecter  58  to the insertion instrument main part  53 . Here, the inclination angle θ 2  of the gas connecter  58  is relatively small, and therefore, the bending part  103  is gentle, and conduit resistance over the whole gas supplying and discharging pass  59  is small. 
     Furthermore, the inner diameter φ 1  of the liquid supplying pass  57  is larger than the inner diameter φ 2  of the gas supplying and discharging pass  59 . That is, regarding the liquid supplying pass  57 , the inner diameter φ 1  is relatively large, conduit resistance over the whole liquid supplying pass  57  is further small. 
     Next, a method for using the insertion instrument according to the present embodiment will be explained. 
     When inserting an endoscope  30  into a cavity in the body, an insertion portion  31  of the endoscope  30  is inserted into a proximal end opening of the insertion instrument main part  53 , and then, while a lubricant is supplied from the liquid connecter  56  through the liquid supplying pass  57  to the inner cavity of the insertion instrument main part  53  of the insertion instrument  52  using a cylinder  51  and so on, the insertion portion  31  is inserted through the insertion instrument main part  53 . The lubricant supplied to the inner cavity of the insertion instrument main part  53  is carried by the insertion portion  31  to be spread to the distal end side following the insertion of the insertion portion  31 , and the lubricant improves a sliding capability between the inner peripheral surface of the insertion instrument  52  and the outer peripheral surface of the insertion portion  31 . 
     Here, as is mentioned above, the conduit resistance of the liquid supplying pass  57  is small, and therefore, resistance in supplying the lubricant through the liquid supplying pass  57  is sufficiently small. Hydrochloric acid lidocaine jelly or glycerol jelly which has large viscosity is used as the lubricant, and therefore, the resistance reducing effect is remarkably exhibited. 
     Moreover, referring to  FIGS. 18A and 18B , when supplying the lubricant by the cylinder  51 , force F, F′ is applied to the liquid connecter  56  in a direction along the liquid supplying pass  57 , that is, in the longitudinal direction of the liquid connecter  56  toward the insertion instrument main part  53 . The force F, F′ may be resolved into component force F 1 , F 1 ′ in the longitudinal direction of the insertion instrument main part  53  and component force Fv, Fv′ in a direction perpendicular to the longitudinal direction. The component force F 1 , F 1 ′ in the longitudinal direction of the insertion instrument main part  53  is to push forward the insertion instrument  52  with respect to the endoscope  30  and is to function to displace the insertion instrument  52  with respect to the endoscope  30 . Here, as shown in  FIG. 18B , in the case where an inclination angle θ 2  of the gas connecter  58  is larger than an inclination angle θ 1  of the liquid connecter  56 , the inclination angle on of the liquid connecter  56  is relatively small, the component force F 1 ′ in the longitudinal direction of the insertion instrument main part  53  is large, and therefore, the insertion instrument  52  is easily displaced with respect to the endoscope  30  due to supplying of the lubricant. In the present embodiment, as shown in  FIG. 18A , the inclination angle θ 1  of the liquid connecter  56  is relatively large, the component force F 1  in the longitudinal direction of the insertion instrument main part  53  is small, and therefore, it is prevented that the insertion instrument  52  is displaced with respect to the endoscope  30  due to supplying of the lubricant. 
     After the insertion instrument  52  and the endoscope  30  is inserted into the cavity in the body together with each other, the insertion instrument  52  and the endoscope  30  is alternately moved forward to be inserted into a deep portion of the cavity in the body. 
     If necessary, a supplying and discharging apparatus  63  is operated through the remote controller  68 , air is supplied through an outer tube  62 , a gas connecter  58  and a gas supplying and discharging pass  59  to the balloon  60  to expand the balloon  60  to hold the inner surface of the body wall. Moreover, air is discharged from the balloon  60  through the gas supplying and discharging pass  59 , the gas connecter  58  and the outer tube  62  to contract the balloon  60  to release the holding to the inner surface of the body wall. Here, as is mentioned above, the conduit resistance of the gas supplying and discharging pass  59  is small, and therefore, resistance in supplying and discharging air through the gas supplying and discharging pass  59  is sufficiently small. 
     Furthermore, referring to  FIGS. 18A and 18B , the outer tube  62  connected to the gas connecter  58  extends toward the proximal end side to the supplying and discharging apparatus  63  and is configured to be moved following movement of the insertion instrument  52 , and therefore, the outer tube  62  may hamper an operation of the insertion instrument  52  and the endoscope  30 . As shown in  FIG. 18B , in the case where an inclination angle θ 2  of the gas connecter  58  is larger than an inclination angle θ 1  of the liquid connecter  56 , the inclination angle θ 2  of the gas connecter  58  is relatively large, an inclination angle of the outer tube  62  is large, and therefore, the outer tube  62  tends to hamper an operation. In the present embodiment, as shown in  FIG. 18A , the inclination angle θ 2  of the gas connecter  58  is relatively small, and therefore, an inclination angle of the outer tube  62  is small and the insertion instrument  52  and the outer tube  62  has an integrated form along the longitudinal direction of the insertion instrument  52 , whereby preventing the outer tube  62  from hampering an operation. 
     As is mentioned above, in the insertion instrument  52  according to the present embodiment, the inclination angle θ 1  of the liquid connecter  56  is relatively large, and therefore, the length of the liquid supplying pass  57  extending from the protruding end of the liquid connecter  56  to the inner cavity of the insertion instrument main part  53  is short, the total length of the liquid supplying pass  57  is short, and the conduit resistance over the whole liquid supplying pass  57  is small. Moreover, the inclination angle θ 2 of the gas connecter  58  is relatively small, and therefore, the bending part  103  of the gas supplying and discharging pass  59  formed from the root end portion of the gas connecter  58  to the insertion instrument main part  53  is gentle, the conduit resistance in the bending part  103  is small, and the conduit resistance over the whole gas supplying and discharging pass  59  is small. Therefore, it is possible to supply the lubricant and supply to and discharge from air at the small resistance. 
     Moreover, the inner diameter φ 1  of the liquid supplying pass  57  is large and the conduit resistance thereof is small, and therefore, regarding the lubricant wherein the viscosity is relatively large and the resistance in supplying tends to be large, it is possible to supply the lubricant at the small resistance. 
     Furthermore, the inclination angle θ 1  of the liquid connecter  56  is large, and therefore, regarding the force applying to the liquid connecter  56  when inserting the endoscope  30  through the insertion instrument  52  and supplying the lubricant to the liquid connecter  56  of the insertion instrument  52 , the component force in the longitudinal direction of the insertion instrument  52  is small, and the insertion instrument  52  is prevented from being displaced with respect to the endoscope  30 . 
     In addition, the inclination angle θ 2  of the gas connecter  58  is small, and therefore, while the outer tube  62  is connected to the gas connecter  58 , the inclination angle of the outer tube  62  is small and the insertion instrument  52  and the outer tube  62  have the integrated form along the longitudinal direction of the insertion instrument  52 , whereby preventing the outer tube  62  from hampering an operation. 
       FIG. 19  shows a first variation example of the sixth embodiment of the present invention. 
     In an insertion instrument  52  according to the variation example, a first and a second balloon  60   a ,  60   b  are arranged side by side in the longitudinal direction of the insertion instrument  52  on the distal end portion of the insertion instrument  52 . A gas supplying and discharging pass  59  is fluidly communicated with the first and the second balloon  60   a ,  60   b.    
       FIG. 20  shows a second variation example of the sixth embodiment of the present invention. 
     In an insertion instrument  52  according to the variation example, as is similar to the first variation example shown in  FIG. 19 , a first and a second balloon  60   a ,  60   b  is provided. A first and a second gas connecter  58   a ,  58   b  is provided on the proximal end portion of the insertion instrument  52 , and the first and the second gas connecter  58   a ,  58   b  is fluidly communicated with the first and the second balloon  60   a ,  60   b  through a first and a second gas supplying and discharging pass  59   a ,  59   b , respectively. 
       FIG. 21  shows a seventh embodiment of the present invention. 
     In the present embodiment, a first to a third balloon  60   a ,  60   b ,  60   c  is arranged side by side in the longitudinal direction of an insertion instrument  52  from the proximal end side to the distal end side on the distal end portion of the insertion instrument  52 . A first to a third gas connecter  58   a ,  58   b ,  58   c  is provided on the proximal end portion of the insertion instrument  52 , and the first to the third gas connecter  58   a ,  58   b ,  58   c  is fluidly communicated with the first to the third balloon  60   a ,  60   b ,  60   c  through a first to a third gas supplying and discharging pass  59   a ,  59   b ,  59   c , respectively. Here, the first to the third gas connecter  58   a ,  58   b ,  58   c  forms a first to a third inclination angle α 1 , α 2 , α 3 , and the second inclination angle α 2  is smaller than the first inclination angle α 1  and the third inclination angle α 3  is smaller than the second inclination angle α 2 . That is, the inclination angle α 2 , α 3  of the gas connecter  58   b ,  58   c  corresponding to the balloon  60   b ,  60   c  on more distal end side is smaller. 
     As is mentioned above, regarding the gas supplying and discharging pass  59   b ,  59   c  which extends to more distal end side, whose total length is larger and whose conduit resistance is larger amoung the gas supplying and discharging passes  59   a ,  59   b ,  59   c  corresponding to the balloons  60   a ,  60   b ,  60   c , the inclination angle α 2 , α 3  of the gas connecter  58   b ,  58   c  is smaller, the bending part  103   b ,  103   c  is gentler, and therefore, the inclination angles α 1 , α 2 , α 3  of the gas connecters  58   a ,  58   b ,  58   c  are optimally set. 
       FIGS. 22A and 22B  show a reference embodiment of the sixth and the seventh embodiment. 
     A distal end cap  54  is provided on the distal end portion of an insertion instrument main part  53 , and protruding portions  104  extend in the longitudinal direction and are arranged side by side at certain intervals over the whole periphery on the inner surface of the distal end cap  54 . In the protruding portion  104 , an apex portion  106  is located on the center line extending in the longitudinal direction. In the transverse cross section cutting the protruding portion  104  perpendicularly to the center line, tapers are formed from the center to both the sides, respectively, and, in the longitudinal cross section cutting the protruding portion  104  along the center line, tapers  105   a ,  105   b  are formed from the apex portion to the distal end side and the proximal end side, respectively. A direction Va extending along the taper  105   a  from the apex portion  106  to the distal end side forms a first taper angle β 1  with respect to a longitudinal direction Ua toward the distal end side, and a direction Vb extending along the taper  105   b  from the apex portion  106  to the proximal end side forms a second taper angle β 2  with respect to a longitudinal direction Ub toward the distal end side. The first taper angle β 1  is larger than the second taper angle β 2 . 
     From the perspective of reducing friction resistance in an insertion of the insertion portion  31  of the endoscope  30 , it is preferable that the inner diameter of the distal end cap  54  of the insertion instrument  52  is sufficiently larger than the outer diameter of an insertion portion  31  of an endoscope  30 . However, in the case where a large clearance is formed between the inner peripheral surface of the distal end cap  54  and the outer peripheral surface of the insertion portion  31 , there is a possibility that a mucosa and the like is drawn into when drawing the insertion portion  31  into the distal end cap  54 . In the reference embodiment, the only apex portion  106  of the protruding portion  104  of the distal end cap  54  is brought into contact with the insertion portion  31  when moving forward and backward the insertion portion  31  of the endoscope  30  with respect to the distal end cap  54 , and therefore, friction resistance between the distal end cap  54  and the insertion portion  31  is sufficiently small. Moreover, when drawing the insertion portion  31  into the distal end cap  54 , the protruding portion  104  prevents the mucosa from being drawn into. Furthermore, in the reference embodiment, the taper angle β 1  on the distal end side of the protruding portion  104  is relatively large, and the apex portion  106  is arranged on the relatively distal end side, and therefore, the mucosa is effectively prevented from being drawn into at the relatively distal end side of the distal end cap  54 . Moreover, in the case where the taper  105   a  is not formed on the distal end side of the protruding portion  104 , there is a possibility that unnecessary force applies to the mucosa while the mucosa is securely prevented from being drawn into, but such a situation is prevented in the reference embodiment. 
     Hereinafter, a eighth to a fourteenth embodiment of the present invention will be explained referring to the drawings. 
     The eighth to the fourteenth embodiment relates to an endoscope apparatus including an endoscope configured to be inserted into a cavity in the body and an insertion instrument adapted to assist an insertion of the endoscope into the cavity in the body. 
     When inserting an insertion portion of an endoscope into a cavity in the body, an insertion instrument adapted to assist an insertion of the insertion portion into the cavity in the body is used. 
     In the endoscope apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2005-118115, an insertion portion of an endoscope is configured to be inserted through an insertion instrument main part having a shape of a sheath so as to be movable forward and backward. When inserting the insertion portion into a deep portion of a complexly bending cavity in the body, the insertion portion is moved forward with respect to the insertion instrument to be passed through a bending portion, and then, the insertion instrument is moved forward along the insertion portion to be passed through the bending portion, and the bending portion is kept in shape by the insertion instrument wherein an insertion can be easily carrid out, after that, the insertion portion is moved forward with respect to the insertion instrument. Furthermore, these operations are repeated. Here, balloons having a doughnut shape are provided on the distal end portion and the proximal end portion of the inner cavity of the insertion instrument coaxially with an insertion instrument main part, respectively. When the balloons are expanded and a liquid is filled into space closed tightly by the inner peripheral surface of the insertion instrument, both the balloons and the outer peripheral surface of the insertion portion to form a liquid layer, the insertion instrument and the insertion portion are scarcely brought into contact with each other, whereby reducing friction resistance between the insertion instrument and the insertion portion. 
     Moreover, in the endoscope apparatus, the insertion portion and an operation portion on the proximal end portion of the endoscope are coupled to each other through a coupling portion and the coupling portion has a larger diameter than that of the insertion portion. When the coupling portion is arranged at the position of the balloon on the proximal end portion of the insertion instrument and the balloon is expanded to tighten the coupling portion, the insertion instrument and the endoscope are fixed to each other. 
     In the endoscope apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2005-118115, the insertion instrument and the endoscope are fixed to each other by expanding the balloon to tighten the insertion portion, and therefore, it is difficult to sufficiently fix the insertion instrument and the endoscope to each other. 
     Moreover, the balloon is provided in the inner cavity of the insertion instrument, and therefore, when inserting the endoscope into the insertion instrument, the balloon and the insertion portion are interfered with each other even when the balloon is contracted and it is impossible to smoothly carry out the insertion of the endoscope. 
     The eighth to the fourteenth embodiment has been made in view of the above mentioned problem and is directed to provide an endoscope apparatus wherein it is possible to sufficiently fix an endoscope and an insertion instrument to each other and smoothly insert the endoscope into the insertion instrument. 
     An endoscope apparatus and an insertion instrument according to the eighth to the fourteenth embodiment have similar structures to those of the endoscope apparatus according to the first embodiment as shown in  FIGS. 1 and 2  and the insertion instrument according to the second embodiment explained referring to  FIGS. 1 and 2 . Hereinafter, configurations differing from the first and the second embodiment are explained in detail. 
       FIG. 23  shows the eighth embodiment of the present invention. 
     Referring to  FIG. 23 , a bending preventing portion  35  of an endoscope  30  has an outer diameter reducing from the proximal end side to the distal end side, and the outer peripheral surface  107  of the bending preventing portion  35  has a tapering shape. The inner diameter of an insertion instrument main part  53  of an insertion instrument  52  is larger than the outer diameter of an insertion portion  31  of the endoscope  30  or the outer diameter of the distal end portion of the bending preventing portion  35 , and is smaller than the outer diameter of the proximal end portion of the bending preventing portion  35 . Therefore, when the insertion portion  31  and then the bending preventing portion  35  are inserted into a proximal end opening of the insertion instrument main part  53  of the insertion instrument  52  and the bending preventing portion  35  is pressed into the insertion instrument main part  53 , the outer peripheral surface  107  of the bending preventing portion  35  is fitted on an edge portion  108  of the proximal end opening of the insertion instrument main part  53 . The diameter of the proximal end opening of the insertion instrument main part  53  of the insertion instrument  52  is larger than the outer diameter of the insertion portion  31 , and therefore, the edge portion  108  of the proximal end opening is not fitted on the insertion portion  31 . 
     That is, in the present embodiment, the outer peripheral surface  107  of the bending preventing portion  35  forms an endoscope fitting portion as an endoscope engagement portion, and the edge portion  108  of the proximal end opening of the insertion instrument main part  53  forms an insertion instrument fitting portion as an insertion instrument engagement portion. 
     Next, a method for using an endoscope apparatus according to the present embodiment will be explained. 
     The endoscope  30  is inserted through the insertion instrument  52 , and the insertion instrument  52  and the endoscope  30  are fixed to each other to be integrated. That is, the insertion portion  31  of the endoscope  30  is inserted into a proximal end opening of the insertion instrument main part  53 , and the insertion portion  31  is inserted through the inner cavity of the insertion instrument main part  53 . In this time, the edge portion  108  of the proximal end opening of the insertion instrument main part  53  does not hamper the insertion of the insertion portion  31 . Next, following the insertion portion  31 , the bending preventing portion  35  is inserted into the proximal end opening of the insertion instrument main part  53 , the bending preventing portion  35  is pressed into the insertion instrument main part  53 , the outer peripheral surface  107  of the bending preventing portion  35  is fitted onto the edge portion  108  of the proximal end opening of the insertion instrument main part  53 . In this way, the insertion instrument  52  and the endoscope  30  is fixed to each other. 
     The insertion instrument  52  and the endoscope  30  are inserted into a cavity in the body together with each other, and when the insertion instrument  52  and the endoscope  30  are reached to the shallow side of a bending part of the cavity in the body, the endoscope  30  is moved backward with respect to the insertion instrument  52 , whereby releasing the fixing between the edge portion  108  of the proximal end opening of the insertion instrument main part  53  of the insertion instrument  52  and the outer peripheral surface  107  of the bending preventing portion  35  of the endoscope  30 . In this way, the fixing between the insertion instrument  52  and the endoscope  30  is released. 
     A supplying and discharging apparatus  63  supplies a gas from the gas connecter  58  through the gas supplying and discharging pass  59  to the balloon  60 , and the balloon  60  is expanded to hold the inner surface of the body wall. In this state, the insertion instrument  52  is moved backward, the body wall is hauled and the bending cavity in the body is made into a shape of a straight line, and then the endoscope  30  is moved forward with respect to the insertion instrument  52  to be passed through the parts of the cavity in the body, which has been bent. Then, when the endoscope  30  is moved forward to reach the shallow side of a next bending part of the cavity in the body, the supplying and discharging apparatus  63  discharge the gas from the balloon  60  of the insertion instrument  52 , and the balloon  60  is contracted to release the holding to the inner surface of the body wall. Next, the insertion instrument  52  is moved forward along the endoscope  30  to the shallow side of the bending part, and the balloon  60  is expanded again to hold the inner surface of the body wall. Here, the cavity in the body is kept in the shape wherein the insertion can be easily carried out, within the range into which the insertion instrument  52  was inserted. After that, similar operations are repeated, and the endoscope  30  is inserted into the deep portion of the complexly bending cavity in the body. If necessary, the insertion instrument  52  and the endoscope  30  are fixed to each other and the fixing is released. 
     The endoscope apparatus according to the present embodiment exhibits the following effect. 
     In the endoscope apparatus according to the present embodiment, it is possible to sufficiently securely fix the endoscope  30  and the insertion instrument  52  to each other by fitting the outer peripheral surface  107  of the bending preventing portion  35  of the endoscope  30  and the edge portion  108  of the proximal end opening of the insertion instrument main part  53  of the insertion instrument  52 . Moreover, it is impossible to fit the edge portion  108  of the proximal end opening of the insertion instrument main part  53  on the insertion portion  31  of the endoscope  30 , and therefore, the edge portion  108  scarcely hampers an insertion when inserting the insertion portion  31  into the insertion instrument  52 , and it is possible to smoothly insert the insertion portion  31  into the insertion instrument  52 . 
       FIG. 24  shows the ninth embodiment of the present invention. 
     In an insertion instrument  52  of an endoscope apparatus according to the present embodiment, a tapering portion  109  is formed on the inner peripheral surface side of the proximal end portion of an insertion instrument main part  53 . The tapering portion  109  has an inner diameter reducing from the proximal end side to the distal end side, and corresponds to a tapering shape of an outer peripheral surface  107  of a bending preventing portion  35  of an endoscope  30 . Therefore, when an insertion portion  31  and then the bending preventing portion  35  are inserted into the proximal end opening of the insertion instrument main part  53 , the outer peripheral surface  107  of the bending preventing portion  35  is fitted on the tapering portion  109  of the proximal end portion of the insertion instrument main part  53 . Moreover, the inner diameter of the distal end portion of the tapering portion  109  is larger than the outer diameter of the insertion portion  31  of the endoscope  30 , and the tapering portion  109  does not fit on the insertion portion  31 . 
     A method for using the endoscope apparatus according to the present embodiment is similar to the method for using the endoscope apparatus according to the eighth embodiment. That is, when fixing the insertion instrument  52  and the endoscope  30  to each other, the insertion portion  31  and then the bending preventing portion  35  is inserted into the proximal end opening of the insertion instrument main part  53  of the insertion instrument  52 , and the outer peripheral surface  107  of the bending preventing portion  35  is fitted onto the tapering portion  109  of the proximal end portion of the insertion instrument main part  53 . Here, the tapering portion  109  of the proximal end portion of the insertion instrument main part  53  does not hamper an insertion of the insertion portion  31 . 
     In the endoscope apparatus according to the present embodiment, the outer peripheral surface  107  of the bending preventing portion  35  which is generally used in the endoscope  30  is utilized for fitting with the insertion instrument  52 , and therefore, it is unnecessary to additionally process the endoscope  30 , and it is possible to inexpensively embody. 
     Moreover, the tapering portion  109  of the proximal end portion of the insertion instrument main part  53  of the insertion instrument  52  and the outer peripheral surface  107  of the bending preventing portion  35  of the endoscope  30  are fitted on each other, and therefore, it is possible to securely fix the insertion instrument  52  and the endoscope  30  to each other in comparison with the endoscope apparatus according to the eighth embodiment. 
       FIG. 25  shows the tenth embodiment of the present invention. 
     In an endoscope apparatus according to the present embodiment, a fitting convex portion  110  is formed on the inner peripheral surface side of the proximal end portion of an insertion instrument main part  53  of an insertion instrument  52  and protrudes radially inwardly. On the other hand, a fitting concave portion  111  is formed on the outer peripheral surface portion of a bending preventing portion  35  of an endoscope  30 , depresses radially inwardly and corresponds to the fitting convex portion  110 . Therefore, when the insertion portion  31  and then the bending preventing portion  3  are inserted into a proximal end opening of the insertion instrument main part  53 , the fitting convex portion  110  of the proximal end portion of the insertion instrument main part  53  is fitted on the fitting concave portion  111  of the bending preventing portion  35 . Moreover, the inner diameter at the radially inwardly end portion of the fitting convex portion  110  is larger than the outer diameter of the insertion portion  31  of the endoscope  30 , and the fitting convex portion  110  is not fitted on the insertion portion  31 . 
     A method for using the endoscope apparatus according to the present embodiment is similar to the method for using the endoscope apparatus according to the eighth embodiment. That is, when fixing the insertion instrument  52  and the endoscope  30  to each other, the insertion portion  31  and then the bending preventing portion  35  are inserted into the proximal end opening of the insertion instrument main part  53  of the insertion instrument  52 , and the fitting convex portion  110  of the proximal end portion of the insertion instrument main part  53  is fitted on the fitting concave portion  111  on the outer peripheral portion of the bending preventing portion  35 . Here, the fitting convex portion  110  of the proximal end portion of the insertion instrument main part  53  does not hamper an insertion of the insertion portion  31 . 
     In the endoscope apparatus according to the present embodiment, the fitting convex portion  110  of the proximal end portion of the insertion instrument main part  53  of the insertion instrument  52  and the fitting concave portion  111  of the outer peripheral portion of the bending preventing portion  35  of the endoscope  30  are fitted on each other, and therefore, it is possible to further securely fix the insertion instrument  52  and the endoscope  30  in comparison with the endoscope apparatus according to the ninth embodiment. 
       FIG. 26  shows the eleventh embodiment of the present invention. 
     In an endoscope apparatus according to the present embodiment, the inner diameter of an insertion instrument main part  53  of an insertion instrument  52  is larger than the outer diameters of an insertion portion  31  of an endoscope  30 , a bending preventing portion  35  and the distal end portion of an operation portion  36 . A pin  112  protrudes radially outwardly from the distal end portion of the operation portion  36  of the endoscope  30 . On the other hand, an engagement groove portion  113  having a shape of a through groove is formed on the proximal end portion of the insertion instrument main part  53  of the insertion instrument  52 , and the pin  112  is slidable in the engagement groove portion  113 . In the engagement groove portion  113 , a guide portion  114  configured to guide the pin  112  extends in the longitudinal direction from the proximal end of the insertion instrument main part  53  and then a holding portion  115  configured to hold the pin  112  extends in the peripheral direction. 
     A method for using the endoscope apparatus according to the present embodiment is similar to the method for using the endoscope apparatus according to the eighth embodiment. However, when fixing the insertion instrument  52  and the endoscope  30  to each other, after the insertion portion  31  and the bending preventing portion  35  are inserted into a proximal end opening of the insertion instrument main part  53 , the insertion instrument  52  is rotated with respect to the endoscope  30  and the pin  112  on the distal end portion of the operation portion  36  of the endoscope  30  is positioned to the inlet of the engagement groove portion  113 . Then, the endoscope  30  is moved forward with respect to the insertion instrument  52  and the pin  112  is slid along the guide portion  114  of the engagement groove portion  113 , and then, the endoscope  30  is rotated with respect to the insertion instrument  52  and the pin  112  is put into and held in the holding portion  115  of the engagement groove portion  113 . As a result, the endoscope  30  is fixed with respect to the insertion instrument  52  so as to be unmovable forward and backward. When releasing the fixing between the insertion instrument  52  and the endoscope  30 , the endoscope  30  is rotated with respect to the insertion instrument  52  and the pin  112  is put into the guide portion  114  from the holding portion  115  of the engagement groove portion  113 , and then, the endoscope  30  is moved backward with respect to the insertion instrument  52  and the pin  112  is slid along the guide portion  114  of the engagement groove portion  113  and pulled out the engagement groove portion  113 . 
     In the endoscope apparatus according to the present embodiment, it is possible to securely fix the endoscope  30  with respect to the insertion instrument  52  so as to be unmovable forward and backward by holding the pin  112  in the holding portion  115  of the engagement groove portion  113 . Moreover, the insertion instrument  52  and the endoscope  30  is fixed and the fixing is released by moving forward and backward and rotating the endoscope  30  with respect to the insertion instrument  52  to guide the pin  112  to and form the holding portion  115  through the guide portion  114  of the engagement groove portion  113 , and therefore, it is possible to easily fix and release at a relatively small amount of operation force in comparison with the case where the fixing is carried out by fitting. 
       FIG. 27  shows the twelfth embodiment of the present invention. 
     In the case where an insertion instrument  52  and an endoscope  30  are fixed to each other through fitting as the ninth embodiment shown in  FIG. 24 , there is a possibility that a fitting surface of the insertion instrument  52  and a fitting surface of the endoscope  30  are adhered to each other when they are kept fitted for a long time. For example, in the case where both the fitting surfaces are made of material which tends to adhere such as silicon, when humor and so on interposed between both the fitting surfaces is dried and hardened, there is a possibility of adhesion. 
     Referring to  FIG. 27 , in the present embodiment, an adhesion preventing mechanism adapted to prevent such adhesion is formed on an insertion instrument fitting portion. That is, a large diameter portion  116  having a large outer diameter is formed on the proximal end portion of the insertion instrument  52 , and a tapering portion  109  similar to that according to the eleventh embodiment is formed on the inner peripheral surface side of the large diameter portion  116 . In the tapering portion  109 , an adhesion preventing groove portion  117  extends in the longitudinal direction. 
     In an endoscope apparatus of the present embodiment, the adhesion preventing groove portion  117  prevents an outer peripheral surface  107  of a bending preventing portion  35  of an endoscope  30  and the tapering portion  109  of the insertion instrument  52  from being adhered to each other, and therefore, it is prevented that releasing the fixing between the insertion instrument  52  and the endoscope  30  is made impossible. 
       FIG. 28  shows the thirteen embodiment of the present invention. 
     In the present embodiment, an adhesion releasing mechanism adapted to release adhesion between a fitting surface of an insertion instrument  52  and a fitting surface of an endoscope  30  is formed on an insertion instrument fitting portion. That is, perforations  121  is formed on the peripheral wall of a large diameter portion  116  of the proximal end portion of an insertion instrument  52 , similar to that according to the twelfth embodiment. The perforations  121  extend from the proximal end of the large diameter portion  116  in the longitudinal direction and then extend in the peripheral direction. A grasping portion  118  is formed on the region surrounded by the perforations  121  on the proximal end of the large diameter portion  116 . When the tapering portion  109  of the large diameter portion  116  of the insertion instrument  52  and an outer peripheral surface  107  of a bending preventing portion  35  of an endoscope  30  are adhered to each other, the grasping portion  118  of the large diameter portion  116  is grasped and pulled up, and the peripheral wall of the large diameter portion  116  is tear along the perforations  121  while cutting the perforations  121 , whereby releasing the adhesion between both the fitting surfaces. 
     That is, in the present embodiment, a breaking mechanism adapted to break the large diameter portion  116  forms an adhesion releasing mechanism. It is noted that the large diameter portion  116  may be configured to be attached to and detached from an insertion instrument main part  53  and the broken large diameter portion  116  may be exchanged for a new large diameter portion  116 . 
     In an endoscope apparatus according to the present embodiment, it is possible to release adhesion between the tapering portion  109  of the large diameter portion  116  of the insertion instrument  52  and the outer peripheral surface  107  of the bending preventing portion  35  of the endoscope  30  by breaking the large diameter portion  116  of the proximal end portion of the insertion portion  31 , and therefore, it is possible to easily release the fixing between the insertion instrument  52  and the endoscope  30  even when the tapering portion  109  and the outer peripheral surface  107  are adhered. 
       FIG. 29  shows the fourteenth embodiment of the present invention. 
     In the present embodiment, a plane surface portion  119  is formed on a bending preventing portion  35  of an endoscope  30  and is configured not to be brought into contact with a tapering portion  109  of an insertion instrument  52 . Therefore, when an outer peripheral surface  107  of the bending preventing portion  35  is fitted on the tapering portion  109 , deformation space is formed between the tapering portion  109  and the plane surface portion  119  of the bending preventing portion  35  and the peripheral wall of a large diameter portion  116  is radially inwardly deformable into the deformation space. In the case where the tapering portion  109  and the outer peripheral surface  107  of the bending preventing portion  35  are adhered to each other, the peripheral wall of the large diameter portion  116  is radially inwardly deformed into the deformation space and the whole peripheral wall of the large diameter portion  116  is deformed into a shape of an ellipse, and the tapering portion  109  and the outer peripheral surface  107  of the bending preventing portion  35  are separated form each other, whereby releasing the adhesion. That is, in the present embodiment, a deformation mechanism adapted to deform the large diameter portion  116  forms an adhesion releasing mechanism. 
     In an endoscope apparatus according to the present embodiment, adhesion is released by deforming the large diameter portion  116  to separate the tapering portion  109  and the outer peripheral surface  107  of the bending preventing portion  35  from each other, and therefore, it is possible to easily and inexpensively release the fixing in comparison with the case where the large diameter portion  116  is broken as the seventh embodiment. 
     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.